Updated on 2024/05/11

写真a

 
HIGUCHI Tomoyuki
 
Organization
Faculty of Science and Engineering Professor
Other responsible organization
Data Science for Business Innovation Course of Graduate School of Science and Engineering, Master's Program
Data Science for Business Innovation Course of Graduate School of Science and Engineering, Doctoral Program
Contact information
The inquiry by e-mail is 《here
Profile

Professor, Department of Data Science for Business Innovation, Faculty of Science and Engineering, Chuo University. I specialize the Bayesian modeling, including data assimilation. I am currently focusing my research on the formulation of deep probabilistic computation, which integrates deep learning and state space modeling. In simulation science, deductive (forward type) reasoning is dominating, where complex phenomena can be described and predicted by elaborating elementary processes. I would like to change the simulation science by promoting the concept of data assimilation. My lifelong research goal is to embed real space into computers, or in other words, to make the matrix of everyday life (← the matrix of the movies).

External link

Degree

  • 理学博士 ( 東京大学 )

  • 理学修士 ( 東京大学 )

Education

  • 1989.3
     

    The University of Tokyo   doctor course   completed

  • 1986.3
     

    The University of Tokyo   master course   completed

  • 1984.3
     

    The University of Tokyo   graduated

Research History

  • 2019.5 - Now

    National Institute of Advanced Industrial Science and Technology   Artificial Intelligence Research Center   Research Emeritus Advisor

  • 2019.4 - Now

    The Graduate University for Advanced Studies   School of Multidisciplinary Sciences Department of Statistical Science   Emeritus Professor

  • 2019.4 - Now

    The Institute of Statistical Mathematics   Emeritus Professor

  • 2019.4 - Now

    Bridgestone Corporation   Digital Solution Center   Distinguished Technical Advisor

  • 2019.4 - Now

    Chuo University   Faculty of Science and Engineering, Department of Data Science for Business Innovation   Professor

  • 2019.4 - 2023.6

    BrainPad Inc.   Advisor

  • 2020.4 - 2023.3

    Chuo University   AI and Data Science Center   Director

  • 2016.4 - 2019.3

    The Graduate University for Advanced Studies, SOKENDAI   Education and Research Council   Education and Research Council

  • 2011.10 - 2019.3

    Research Organization of Information and Systems

  • 2011.4 - 2019.3

    The Institute of Statistical Mathematics   Director in General

  • 2005 - 2019.3

    The Institute of Statistical Mathematics   Department of Statistical Modeling   Professor

  • 2010 - 2011

    The Institute of Statistical Mathematics   Department of Statistical Modeling

  • 2005 - 2010

    Research Organization of Information and Systems

  • 2004 - 2010

    The Institute of Statistical Mathematics

  • 2002 - 2005

    The Institute of Statistical Mathematics   Professor

  • 1994 - 2002

    The Institute of Statistical Mathematics   Department of Prediction and Control   Associate Professor

  • 1989 - 1994

    The Institute of Statistical Mathematics   Research Assistant

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Professional Memberships

  • THE JAPAN SOCIETY FOR INDUSTRIAL AND APPLIED MATHEMATICS

  • Japanese Society for Computational Statistics

  • Japan Society of Applied Statistics

  • American Statistical Association

  • International Statistical Institute

  • Japanese Society for Artificial Intelligence

  • The Institute of Electronics, Information and Communication Engineers (IEICE)

  • Japan Statistical Society

  • Japan Geoscience Union (JpGU)

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Research Interests

  • State space representation

  • Soft computing

  • Spectral Discrimination

  • Generalized State Space Model

  • Seasonal variation

  • Sampling

  • Count data

  • Spectral analysis

  • Bayesian statistics

  • Graphical models

  • Monte Carlo methods

  • Multivariate time series

  • Genetic algorithms

  • Simulations

  • Satellite

  • Spatio-temporal models

  • Hyperparameter

  • Bayesian inference

  • Markov Switching

  • Kullback-Librar Kernel

  • Seasonal adjustment method

  • Particle filter

  • Target tracking

  • Hierarchical Bayes

  • Discovery Science

  • Self-organizing models

  • Non-Gaussian

  • Modeling

  • Non-Gaussian filter

  • General state space model

  • Non-stationary time series

  • Model Integration

  • Prediction

  • Nonparametric

  • Kalman filter

  • Time series

  • Ultra-multivariate time series

  • State space models

  • Bayesian model

  • Time series analysis

  • Self-organization

  • Nonlinear

  • Parallel computing

  • Trend

  • FoS

  • Self-organizing time series models

  • Seasonal component

Research Areas

  • Life Science / Genome biology

  • Life Science / System genome science

  • Informatics / Intelligent informatics

  • Informatics / Statistical science

  • Natural Science / Space and planetary sciences

  • Informatics / Life, health and medical informatics

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Papers

  • 生産ラインにおける異常検知・非定常サイクル同定のオンラインシステム Reviewed

    石曽根 毅, 樋口 知之, 中村 和幸

    計測自動制御学会論文集   59 ( 7 )   342 - 352   2023.7

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    Language:Japanese   Publisher:公益社団法人 計測自動制御学会  

    DOI: 10.9746/sicetr.59.342

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  • Ensemble kalman variational objective: a variational inference framework for sequential variational auto-encoders Reviewed

    Tsuyoshi Ishizone, Tomoyuki Higuchi, Kazuyuki Nakamura

    Nonlinear Theory and Its Applications, IEICE   14 ( 4 )   691 - 717   2023

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Institute of Electronics, Information and Communications Engineers (IEICE)  

    DOI: 10.1587/nolta.14.691

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  • The Occurrence of Embedded Region 1 and 2 Currents Depends on Geomagnetic Activity Level Reviewed International journal

    Jiang Liu, T. Higuchi, L. R. Lyons, Shinichi Ohtani, Jiashu Wu, Ying Zou, V. Angelopoulos, Chih‐Ping Wang

    Journal of Geophysical Research: Space Physics   127 ( 11 )   2022.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union (AGU)  

    DOI: 10.1029/2022ja030539

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  • An Online System of Detecting Anomalies and Estimating Cycle Times for Production Lines Reviewed International journal

    Tsuyoshi Ishizone, Tomoyuki Higuchi, Kosuke Okusa, Kazuyuki Nakamura

    IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society   2022.10

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/iecon49645.2022.9969061

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  • Occupancy Detection for General Households by Bidirectional LSTM with Attention Reviewed International journal

    Hisashi Oshima, Tsuyoshi Ishizone, Kazuyuki Nakamura, Tomoyuki Higuchi

    IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society   2022.10

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    DOI: 10.1109/iecon49645.2022.9968594

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  • 家庭用スマートメータへの適用を目的とする世帯の在宅推定手法の開発 Reviewed

    大島悠, 石曽根毅, 樋口知之

    情報処理学会論文誌 デジタルプラクティス   51   2022.7

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  • 隣接領域との競争と共創が促す統計学の力強い発展 Reviewed

    樋口 知之

    日本統計学会誌   51 ( 2 )   213 - 244   2022.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:一般社団法人日本統計学会  

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  • Data-Driven Road Condition Forecasting with High Spatial Resolution: Utilizing Tire-Centric Road Condition Monitoring Technology Reviewed International journal

    Teppei Mori, Tomonori Ohiro, Yasushi Hanatsuka, Tomoyuki Higuchi

    2020 IEEE 23rd International Conference on Intelligent Transportation Systems (ITSC)   2020.9

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    DOI: 10.1109/itsc45102.2020.9294592

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  • モデリング変革の4半世紀を振り返って Invited Reviewed

    樋口 知之

    統計数理   67 ( 2 )   157 - 164   2019.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:統計数理研究所  

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  • Reconstructing the transmission dynamics of rubella in Japan, 2012-2013 Reviewed International journal

    Masaya M. Saito, Hiroshi Nishiura, Tomoyuki Higuchi

    PLOS ONE   13 ( 10 )   e0205889 - e0205889   2018.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Public Library of Science (PLoS)  

    BACKGROUND: Japan experienced a nationwide rubella epidemic from 2012 to 2013, mostly in urban prefectures with large population sizes. The present study aimed to capture the spatiotemporal patterns of rubella using a parsimonious metapopulation epidemic model and examine the potential usefulness of spatial vaccination. METHODOLOGY/PRINCIPAL FINDINGS: A metapopulation epidemic model in discrete time and space was devised and applied to rubella notification data from 2012 to 2013. Employing a piecewise constant model for the linear growth rate in six different time periods, and using the particle Markov chain Monte Carlo method, the effective reproduction numbers were estimated at 1.37 (95% CrI: 1.12, 1.77) and 1.37 (95% CrI: 1.24, 1.48) in Tokyo and Osaka groups, respectively, during the growing phase of the epidemic in 2013. The rubella epidemic in 2012 involved substantial uncertainties in its parameter estimates and forecasts. We examined multiple scenarios of spatial vaccination with coverages of 1%, 3% and 5% for all of Japan to be distributed in different combinations of prefectures. Scenarios indicated that vaccinating the top six populous urban prefectures (i.e., Tokyo, Kanagawa, Osaka, Aichi, Saitama and Chiba) could potentially be more effective than random allocation. However, greater uncertainty was introduced by stochasticity and initial conditions such as the number of infectious individuals and the fraction of susceptibles. CONCLUSIONS: While the forecast in 2012 was accompanied by broad uncertainties, a narrower uncertainty bound of parameters and reliable forecast were achieved during the greater rubella epidemic in 2013. By better capturing the underlying epidemic dynamics, spatial vaccination could substantially outperform the random vaccination.

    DOI: 10.1371/journal.pone.0205889

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  • 災害時におけるリアルタイムな広域人流推定のための高精度な粒子フィルタの提案 Reviewed

    須藤明人, 樫山武浩, 矢部貴大, 樋口知之, 中野慎也, 斎藤正也, 関本義秀

    交通工学論文集   3 ( 2 )   A_76 - A_83   2017.3

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    Language:Japanese  

    DOI: 10.14954/jste.3.2_A_76

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  • Bayesian Inference of Forces Causing Cytoplasmic Streaming in Caenorhabditis elegans Embryos and Mouse Oocytes Reviewed

    Ritsuya Niwayama, Hiromichi Nagao, Tomoya S. Kitajima, Lars Hufnagel, Kyosuke Shinohara, Tomoyuki Higuchi, Takuji Ishikawa, Akatsuki Kimura

    PLOS ONE   11 ( 7 )   2016.7

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    Cellular structures are hydrodynamically interconnected, such that force generation in one location can move distal structures. One example of this phenomenon is cytoplasmic streaming, whereby active forces at the cell cortex induce streaming of the entire cytoplasm. However, it is not known how the spatial distribution and magnitude of these forces move distant objects within the cell. To address this issue, we developed a computational method that used cytoplasm hydrodynamics to infer the spatial distribution of shear stress at the cell cortex induced by active force generators from experimentally obtained flow field of cytoplasmic streaming. By applying this method, we determined the shear-stress distribution that quantitatively reproduces in vivo flow fields in Caenorhabditis elegans embryos and mouse oocytes during meiosis II. Shear stress in mouse oocytes were predicted to localize to a narrower cortical region than that with a high cortical flow velocity and corresponded with the localization of the cortical actin cap. The predicted patterns of pressure gradient in both species were consistent with species-specific cytoplasmic streaming functions. The shear-stress distribution inferred by our method can contribute to the characterization of active force generation driving biological streaming.

    DOI: 10.1371/journal.pone.0159917

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  • データサイエンティスト育成と人材利活用のベスト・プラクティス Invited

    丸山宏, 神谷直樹, 樋口知之, 竹村彰通, 大西立顕

    デジタルプラクティス   6 ( 3 )   223 - 229   2016.7

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  • 非線形埋込み型特徴量選択のための単結合ニューラルネットワークの提案

    須藤明人, 樋口知之, 中野慎也, 斎藤正也, 矢部貴大, 関本義秀

    電子情報通信学会技術研究報告   116 ( 121 )   127 - 131   2016.6

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  • A sequential Bayesian approach for the estimation of the age-depth relationship of the Dome Fuji ice core Reviewed

    Shin'ya Nakano, Kazue Suzuki, Kenji Kawamura, Frederic Parrenin, Tomoyuki Higuchi

    NONLINEAR PROCESSES IN GEOPHYSICS   23 ( 1 )   31 - 44   2016

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:COPERNICUS GESELLSCHAFT MBH  

    A technique for estimating the age-depth relationship in an ice core and evaluating its uncertainty is presented. The age-depth relationship is determined by the accumulation of snow at the site of the ice core and the thinning process as a result of the deformation of ice layers. However, since neither the accumulation rate nor the thinning process is fully known, it is essential to incorporate observational information into a model that describes the accumulation and thinning processes. In the proposed technique, the age as a function of depth is estimated by making use of age markers and delta O-18 data. The age markers provide reliable age information at several depths. The data of delta O-18 are used as a proxy of the temperature for estimating the accumulation rate. The estimation is achieved using the particle Markov chain Monte Carlo (PMCMC) method, which is a combination of the sequential Monte Carlo (SMC) method and the Markov chain Monte Carlo method. In this hybrid method, the posterior distributions for the parameters in the models for the accumulation and thinning process are computed using the Metropolis method, in which the likelihood is obtained with the SMC method, and the posterior distribution for the age as a function of depth is obtained by collecting the samples generated by the SMC method with Metropolis iterations. The use of this PMCMC method enables us to estimate the age-depth relationship without assuming either linearity or Gaussianity. The performance of the proposed technique is demonstrated by applying it to ice core data from Dome Fuji in Antarctica.

    DOI: 10.5194/npg-23-31-2016

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  • Particle Filter for Real-time Human Mobility Prediction following Unprecedented Disaster Reviewed

    Akihito Sudo, Takehiro Kashiyama, Takahiro Yabe, Hiroshi Kanasugi, Xuan Song, Tomoyuki Higuchi, Shin'ya Nakano, Masaya Saito, Yoshihide Sekimoto

    24TH ACM SIGSPATIAL INTERNATIONAL CONFERENCE ON ADVANCES IN GEOGRAPHIC INFORMATION SYSTEMS (ACM SIGSPATIAL GIS 2016)   2016

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:ASSOC COMPUTING MACHINERY  

    Real-time estimation of human mobility following a massive disaster will play a crucial role in disaster relief. Because human mobility in massive disasters is quite different from their usual mobility, real-time human location data is necessary for precise estimation. Due to privacy concerns, real-time data is anonymized and a popular form of anonymization is population distribution. In this paper, we aim to estimate human mobility following an unprecedented disaster using such population distribution data. To overcome technical obstacles including high dimensionality, we propose novel particle filter by devising proposal distribution. Our proposal distribution provides states considering both prediction model and acquired observation. Therefore, particles maintain high likelihood. In the experiments, our methods realized more accurate estimation than the baselines, and its estimated mobility was consistent with the survey researches. The computational cost is significantly low enough for real-time operations. The GPS data collected on the day of the Great East Japan Earthquake is used for the evaluation.

    DOI: 10.1145/2996913.2997000

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  • Elevated β-catenin pathway as a novel target for patients with resistance to EGF receptor targeting drugs. Reviewed International journal

    Asuka Nakata, Ryo Yoshida, Rui Yamaguchi, Mai Yamauchi, Yoshinori Tamada, Andre Fujita, Teppei Shimamura, Seiya Imoto, Tomoyuki Higuchi, Masaharu Nomura, Tatsuo Kimura, Hiroshi Nokihara, Masahiko Higashiyama, Kazuya Kondoh, Hiroshi Nishihara, Arinobu Tojo, Seiji Yano, Satoru Miyano, Noriko Gotoh

    Scientific reports   5   13076 - 13076   2015.8

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    There is a high death rate of lung cancer patients. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are effective in some lung adenocarcinoma patients with EGFR mutations. However, a significant number of patients show primary and acquire resistance to EGFR-TKIs. Although the Akt kinase is commonly activated due to various resistance mechanisms, the key targets of Akt remain unclear. Here, we show that the Akt-β-catenin pathway may be a common resistance mechanism. We analyzed gene expression profiles of gefitinib-resistant PC9M2 cells that were derived from gefitinib-sensitive lung cancer PC9 cells and do not have known resistance mechanisms including EGFR mutation T790M. We found increased expression of Axin, a β-catenin target gene, increased phosphorylation of Akt and GSK3, accumulation of β-catenin in the cytoplasm/nucleus in PC9M2 cells. Both knockdown of β-catenin and treatment with a β-catenin inhibitor at least partially restored gefitinib sensitivity to PC9M2 cells. Lung adenocarcinoma tissues derived from gefitinib-resistant patients displayed a tendency to accumulate β-catenin in the cytoplasm. We provide a rationale for combination therapy that includes targeting of the Akt-β-catenin pathway to improve the efficacy of EGFR-TKIs.

    DOI: 10.1038/srep13076

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  • Developing data analytics skills in Japan: status and challenge Reviewed

    H. Maruyama, N. Kamiya, T. Higuchi, A. Takemura

    J. Jpn. Ind. Manage. Assoc.   Vol.65 ( No.4E )   334 - 339   2015.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Japan Industrial Management Association  

    Japan needs to develop data analytics talent quickly in order to catch up with the trend of using data for making business decisions. The Ministry of Education, Culture, Sports, Science and Technology started a three-year project to develop so-called data scientists. This paper reviews the findings of the first year of the project, and discusses future challenges.

    DOI: 10.11221/jima.65.334

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  • ROAD CONDITION CLASSIFICATION USING A NEW GLOBAL ALIGNMENT KERNEL Reviewed

    Takato Goto, Yasushi Hanatsuka, Tomoyuki Higuchi, Tomoko Matsui

    2015 IEEE INTERNATIONAL WORKSHOP ON MACHINE LEARNING FOR SIGNAL PROCESSING   1 - 6   2015

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    The development of the so-called intelligent tire has changed the role of the tire. Here we discuss a real-time road condition classification system that employs monitoring tire acceleration. Because the tire acceleration is non-stationary and is warped non-linearly in the time domain, we applied the time alignment algorithm to it similarly to speech recognition. High accuracy classification systems robust against tire-size range variations have been achieved in previous studies, in which the same pattern tires with prescribed pressure and several vehicles were used. However, there is no discussion on the execution speed of such a system. Therefore, we validated the algorithm and improved it for use in real-time applications. Specially, the calculation time was reduced by limiting the path of the global alignment kernel, which handles a sequence with time warping. Furthermore, we used SVM with L1 norm regularization instead of L2 norm regularization. We succeeded in achieving a real-time road condition classification system, which was verified in a vehicle test.

    DOI: 10.1109/MLSP.2015.7324381

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  • Atom Environment Kernels on Molecules Reviewed

    Hiroshi Yamashita, Tomoyuki Higuchi, Ryo Yoshida

    JOURNAL OF CHEMICAL INFORMATION AND MODELING   54 ( 5 )   1289 - 1300   2014.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER CHEMICAL SOC  

    The measurement of molecular similarity is an essential part of various machine learning tasks in chemical informatics. Graph kernels provide good similarity measures between molecules. Conventional graph kernels are based on counting common subgraphs of specific types in the molecular graphs. This approach has two primary limitations: (i) only exact subgraph matching is considered in the counting operation, and (ii) most of the subgraphs will be less relevant to a given task. In order to address the above-mentioned limitations, we propose a new graph kernel as an extension of the subtree kernel initially proposed by Ramon and Gartner (2003). The proposed kernel tolerates an inexact match between subgraphs by allowing matching between atoms with similar local environments. In addition, the proposed kernel provides a method to assign an importance weight to each subgraph according to the relevance to the task, which is predetermined by a statistical test. These extensions are evaluated for classification and regression tasks of predicting a wide range of pharmaceutical properties from molecular structures, with promising results.

    DOI: 10.1021/ci400403w

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  • Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images Reviewed

    S. Nakano, M-C. Fok, P. C. Brandt, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 5 )   3708 - 3723   2014.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    We have developed a technique for estimating the temporal evolution of the plasmaspheric helium ion density based on a sequence of extreme ultraviolet (EUV) data obtained from the IMAGE satellite. In the proposed technique, the estimation is obtained by incorporating EUV images from IMAGE into a two-dimensional fluid model of the plasmasphere using a data assimilation approach based on the ensemble transform Kalman filter. Since the motion and the spatial structure of the helium plasmasphere is strongly controlled by the electric field in the inner magnetosphere, the electric field around the plasmapause can also be estimated using the ensemble transform Kalman filter. We performed an experiment using synthetic images that were generated from the same numerical model under a certain condition. It was confirmed that the condition that generated the synthetic images was successfully reproduced. We also present some results obtained using real EUV imaging data. Finally, we discuss the possibility of estimating the density profile along a magnetic field line. Since each EUV image was taken from a different direction due to the motion of the IMAGE satellite, we could obtain the information on the density profile along a field line by combining multiple images.

    DOI: 10.1002/2013JA019734

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  • Estimation of the helium ion density distribution in the plasmasphere based on a single IMAGE/EUV image Reviewed

    S. Nakano, M. -C. Fok, P. C. Brandt, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 5 )   3724 - 3740   2014.5

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    We have developed a technique by which to estimate the spatial distribution of plasmaspheric helium ions based on extreme ultraviolet (EUV) data obtained from the IMAGE satellite. The estimation is performed using a linear inversion method based on the Bayesian approach. The global imaging data from the IMAGE satellite enable us to estimate a global two-dimensional distribution of the helium ions in the plasmasphere. We applied this technique to a synthetic EUV image generated from a numerical model. This technique was confirmed to successfully reproduce the helium ion density that generated the synthetic EUV data. We also demonstrate how the proposed technique works for real data using two real EUV images.

    DOI: 10.1002/2013JA019733

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  • Field-aligned currents during the extreme solar minimum between the solar cycles 23 and 24 Reviewed

    Simon Wing, Shinichi Ohtani, Jay Johnson, Gordon R. Wilson, Tomoyuki Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 4 )   2466 - 2475   2014.4

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    The solar minimum between solar cycles 23 and 24 was unusually long and deep. The upward region-1 (R1) field-aligned current (FAC) response to this extreme solar minimum was investigated using Defense Meteorological Satellite Program observations. The solar cycle responses on the dayside are different than those on the nightside. The field-aligned current density (J(//)) on the dayside, at 12-17 magnetic local time (MLT), peaks in the declining phase of the solar cycle, in 2003, when the solar wind speed also peaks, whereas J(//) on the nightside, at 18-23 MLT, appears insensitive to the solar cycle. In 1995-2010, J(//) at 15-17 MLT reaches the lowest value during the extreme solar minimum in 2009, when the solar wind speed also reaches the lowest value. At 12-17 MLT, R1 is located mostly on open field lines or at the boundary layer, where the current is driven mostly by the velocity shear at the magnetopause boundary. However, on the nightside, R1 is located mostly on the closed field lines where J(//) is not driven directly and immediately by the solar wind. The nightside current width () exhibits a solar cycle effect such that is smaller at the solar minimum and smallest in 2009. However, the dayside exhibits little solar cycle effect. As a result, the FAC intensity (latitudinally integrated J(//)) exhibits a solar cycle variation at all local times and the FAC intensity is lower during the extreme solar minimum than that of the previous solar minimum.

    DOI: 10.1002/2013JA019452

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  • Solar cycle dependence of nightside field-aligned currents: Effects of dayside ionospheric conductivity on the solar wind-magnetosphere-ionosphere coupling Reviewed

    S. Ohtani, S. Wing, V. G. Merkin, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   119 ( 1 )   322 - 334   2014.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    In the present study we observationally address the role of ionospheric conductivity in the solar wind-magnetosphere coupling in terms of global field-aligned currents (FACs). Solar EUV irradiance changes during a solar cycle and so does its contribution to the ionospheric conductivity. We statistically examine how, under fixed external conditions, the intensities of the R1 and R2 currents and their demarcation latitude depend on solar activity (F-10.7). An emphasis is placed on nightside FACs in the dark hemisphere. The result shows that for fixed ranges of interplanetary electric field, the nightside FACs are more intense for higher solar activity irrespective of their polarities or local times. It is also found that the R1-R2 pair, therefore the auroral oval, moves equatorward as the solar activity increases. For both current intensity and latitude, the dependence on F-10.7 is more sensitive at smaller F-10.7 and it levels off with increasing F-10.7. The intensities of dayside FACs reveal similar F-10.7 dependence as expected from the enhancement of the local ionospheric conductance. Interestingly, they also move equatorward with increasing F-10.7. It is expected from force balance that as the dayside R1 current becomes more intense with increasing solar activity, the magnetosphere shrinks on the day side and expands on the night side. This configurational change of the magnetosphere presumably affects the energy transport from the solar wind to the magnetosphere, although its details still remain to be understood. We conclude that the ionospheric conductivity plays an active role in the solar wind-magnetosphere-ionosphere coupling.

    DOI: 10.1002/2013JA019410

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  • Parameter estimation in multi-compartment SIR model Reviewed

    Masaya M. Saito, Seiya Imoto, Rui Yamaguchi, Satoru Miyano, Tomoyuki Higuchi

    2014 17TH INTERNATIONAL CONFERENCE ON INFORMATION FUSION (FUSION)   2014

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    Sentinel observations of influenza epidemic in each prefecture indicates basically unimodal trend but with irregular shocks, which are synchronous among prefectures. In this study, we have confirmed that the the strength of inter-regional connection and local probabilistic fluctuation are separately identifiable in a multi-compartment SIR model.

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  • Solar cycle dependence of nightside field-aligned currents: Effects of dayside ionospheric conductivity on the solar wind-magnetosphere-ionosphere coupling Reviewed

    S. Ohtani, S. Wing, V. G. Merkin, T. Higuchi

    Journal of Geophysical Research: Space Physics   119 ( 1 )   322 - 334   2014

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Blackwell Publishing Ltd  

    In the present study we observationally address the role of ionospheric conductivity in the solar wind-magnetosphere coupling in terms of global field-aligned currents (FACs). Solar EUV irradiance changes during a solar cycle and so does its contribution to the ionospheric conductivity. We statistically examine how, under fixed external conditions, the intensities of the R1 and R2 currents and their demarcation latitude depend on solar activity (F 10.7). An emphasis is placed on nightside FACs in the dark hemisphere. The result shows that for fixed ranges of interplanetary electric field, the nightside FACs are more intense for higher solar activity irrespective of their polarities or local times. It is also found that the R1-R2 pair, therefore the auroral oval, moves equatorward as the solar activity increases. For both current intensity and latitude, the dependence on F 10.7 is more sensitive at smaller F10.7 and it levels off with increasing F10.7. The intensities of dayside FACs reveal similar F10.7 dependence as expected from the enhancement of the local ionospheric conductance. Interestingly, they also move equatorward with increasing F10.7. It is expected from force balance that as the dayside R1 current becomes more intense with increasing solar activity, the magnetosphere shrinks on the day side and expands on the night side. This configurational change of the magnetosphere presumably affects the energy transport from the solar wind to the magnetosphere, although its details still remain to be understood. We conclude that the ionospheric conductivity plays an active role in the solar wind-magnetosphere-ionosphere coupling. Key Points Nightside R1 and R2 currents become more intense with increasing solar activity The auroral oval moves equatorward as solar activity increases The dayside conductivity affects the SW-M-I coupling through the R1 system. ©2013. American Geophysical Union. All Rights Reserved.

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  • Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images Reviewed

    S. Nakano, M. C. Fok, P. C. Brandt, T. Higuchi

    Journal of Geophysical Research: Space Physics   119 ( 5 )   3708 - 3723   2014

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    We have developed a technique for estimating the temporal evolution of the plasmaspheric helium ion density based on a sequence of extreme ultraviolet (EUV) data obtained from the IMAGE satellite. In the proposed technique, the estimation is obtained by incorporating EUV images from IMAGE into a two-dimensional fluid model of the plasmasphere using a data assimilation approach based on the ensemble transform Kalman filter. Since the motion and the spatial structure of the helium plasmasphere is strongly controlled by the electric field in the inner magnetosphere, the electric field around the plasmapause can also be estimated using the ensemble transform Kalman filter. We performed an experiment using synthetic images that were generated from the same numerical model under a certain condition. It was confirmed that the condition that generated the synthetic images was successfully reproduced. We also present some results obtained using real EUV imaging data. Finally, we discuss the possibility of estimating the density profile along a magnetic field line. Since each EUV image was taken from a different direction due to the motion of the IMAGE satellite, we could obtain the information on the density profile along a field line by combining multiple images. Key Points A data assimilation approach is applied for modeling the plasmasphere The proposed technique allows us to estimate the evolution of He+ distribution The parameter for the profile along a field line could also be estimated ©2014. American Geophysical Union. All Rights Reserved.

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  • Estimation of the helium ion density distribution in the plasmasphere based on a single IMAGE/EUV image Reviewed

    S. Nakano, M. C. Fok, P. C. Brandt, T. Higuchi

    Journal of Geophysical Research: Space Physics   119 ( 5 )   3724 - 3740   2014

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    We have developed a technique by which to estimate the spatial distribution of plasmaspheric helium ions based on extreme ultraviolet (EUV) data obtained from the IMAGE satellite. The estimation is performed using a linear inversion method based on the Bayesian approach. The global imaging data from the IMAGE satellite enable us to estimate a global two-dimensional distribution of the helium ions in the plasmasphere. We applied this technique to a synthetic EUV image generated from a numerical model. This technique was confirmed to successfully reproduce the helium ion density that generated the synthetic EUV data. We also demonstrate how the proposed technique works for real data using two real EUV images. Key Points A technique to estimate the plasmaspheric He+ density distribution is proposed The estimation is based on EUV data from the IMAGE satellite The uncertainty and sensitivity of the estimate are also evaluated ©2014. American Geophysical Union. All Rights Reserved.

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  • Field-aligned currents during the extreme solar minimum between the solar cycles 23 and 24 Reviewed

    Simon Wing, Shinichi Ohtani, Jay Johnson, Gordon R. Wilson, Tomoyuki Higuchi

    Journal of Geophysical Research: Space Physics   119 ( 4 )   2466 - 2475   2014

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    The solar minimum between solar cycles 23 and 24 was unusually long and deep. The upward region-1 (R1) field-aligned current (FAC) response to this extreme solar minimum was investigated using Defense Meteorological Satellite Program observations. The solar cycle responses on the dayside are different than those on the nightside. The field-aligned current density (J//) on the dayside, at 12-17 magnetic local time (MLT), peaks in the declining phase of the solar cycle, in 2003, when the solar wind speed also peaks, whereas J// on the nightside, at 18-23 MLT, appears insensitive to the solar cycle. In 1995-2010, J// at 15-17 MLT reaches the lowest value during the extreme solar minimum in 2009, when the solar wind speed also reaches the lowest value. At 12-17 MLT, R1 is located mostly on open field lines or at the boundary layer, where the current is driven mostly by the velocity shear at the magnetopause boundary. However, on the nightside, R1 is located mostly on the closed field lines where J// is not driven directly and immediately by the solar wind. The nightside current width (Λ) exhibits a solar cycle effect such that Λ is smaller at the solar minimum and smallest in 2009. However, the dayside Λ exhibits little solar cycle effect. As a result, the FAC intensity (latitudinally integrated J//) exhibits a solar cycle variation at all local times and the FAC intensity is lower during the extreme solar minimum than that of the previous solar minimum. Key Points Upward R1 responds to solar cycle differently in the closed than open field line Dayside R1 J// has a strong solar cycle variation which can be attributed to Vsw R1 FAC intensity exhibits a solar cycle variation at 1200-2300 MLT ©2014. American Geophysical Union. All Rights Reserved.

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  • Data assimilation system for seismoacoustic waves-verification by atwin experiment- Reviewed

    Nagao H, Higuchi T

    The institute of statistical mathematics   61巻 ( 2号 )   257 - 270   2013.12

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  • Extension and verification of the SEIR model on the 2009 influenza A (H1N1) pandemic in Japan Reviewed

    Masaya M. Saito, Seiya Imoto, Rui Yamaguchi, Hiroki Sato, Haruka Nakada, Masahiro Kami, Satoru Miyano, Tomoyuki Higuchi

    MATHEMATICAL BIOSCIENCES   246 ( 1 )   47 - 54   2013.11

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    In order to understand the evolution of the 2009 influenza A (H1N1) pandemic within local regions of Japan, we studied the significance of regional migration between these regions. For this purpose, we have employed an extended SEIR model to describe the immigration of infected people and the stochastic variation of the infectious efficiency. We then applied a data assimilation technique in order to study how the agreement of the simulation results with the observed data depends on the presence/absence of immigration and the degree of variation of the infectious efficiency. Reproducibility is evaluated by log-likelihood values. The log-likelihood does not indicate the significance of immigration. Although there are multiple waves in the time course of the number of reported infected individuals, these waves could be explained by the stochastic nature of infectious events. (C) 2013 Elsevier Inc. All rights reserved.

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  • Enhancement of Collective Immunity in Tokyo Metropolitan Area by Selective Vaccination against an Emerging Influenza Pandemic Reviewed

    Masaya M. Saito, Seiya Imoto, Rui Yamaguchi, Masaharu Tsubokura, Masahiro Kami, Haruka Nakada, Hiroki Sato, Satoru Miyano, Tomoyuki Higuchi

    PLOS ONE   8 ( 9 )   e43923   2013.9

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    Vaccination is a preventive measure against influenza that does not require placing restrictions on social activities. However, since the stockpile of vaccine that can be prepared before the arrival of an emerging pandemic strain is generally quite limited, one has to select priority target groups to which the first stockpile is distributed. In this paper, we study a simulation-based priority target selection method with the goal of enhancing the collective immunity of the whole population. To model the region in which the disease spreads, we consider an urban area composed of suburbs and central areas connected by a single commuter train line. Human activity is modelled following an agent-based approach. The degree to which collective immunity is enhanced is judged by the attack rate in unvaccinated people. The simulation results show that if students and office workers are given exclusive priority in the first three months, the attack rate can be reduced from 30% in the baseline case down to 1-2%. In contrast, random vaccination only slightly reduces the attack rate. It should be noted that giving preference to active social groups does not mean sacrificing those at high risk, which corresponds to the elderly in our simulation model. Compared with the random administration of vaccine to all social groups, this design successfully reduces the attack rate across all age groups.

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  • Data assimilation system for seismoacoustic waves Reviewed

    Nagao H, Higuchi T

    Proceedings of 16th International Conference on Information Fusion   1372 - 1377   2013.7

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  • An Analysis of Purchase History Data by a Brand Choice Model Considering the Change of Market Structure Reviewed

    Vol.21 ( No.1 )   37 - 59   2013.7

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    DOI: 10.11295/marketingscience.210103

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  • Data scientist: a key factor in innovation driven by big data

    Higuchi T

    Journal of Information Processing and Management   Vol.56 ( No.1 )   2 - 11   2013.4

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    To develop an efficient way of generating innovation driven by big data is a central issue in academia as well as industry. Although such a demand grows rapidly, a human resource development that is a key factor for realizing it remains the rarely-discussed problem. A data scientist with sufficient knowledge in statistics and machine learning is exactly a right person who plays a crucial role in making effective use of big data. In fact, the business community, in particular, social network game company has made significant efforts to attract them. In this paper, we address a problem in developing data scientists in Japan, and give a brief introduction of interesting internship program for PhD candidate or post-doctoral researcher which the Silicon Valley technology companies initiated in summer, 2012. Its program is designed to bridge a gap between academia and a career data science. Finally, we consider how to increase the data scientist in Japan effectively, and propose to realize a Japanese version of that program as soon as possible with a financial support of Japanese government.

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  • Time-series modeling of tide gauge records for monitoring of the crustal activities related to oceanic trench earthquakes around Japan Reviewed

    Hiromichi Nagao, Tomoyuki Higuchi, Satoshi Miura, Daisuke Inazu

    Computer Journal   56 ( 3 )   355 - 364   2013.3

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    Tide gauge observations along the coastline of Japan have recorded the land sinking due to the continuous subduction of the oceanic plates, indicating that stress and strain energies have been accumulating at the plate boundary, which would eventually cause large oceanic trench earthquakes like the 2011 Great East Japan Earthquake. The proposed method extracts such long-term activities of the Earth's crust together with rapid displacements related to earthquakes, even before the establishment of the global positioning system, from monthly mean data of the sea levels. A state space model decomposes the tide gauge time series into trend, seasonal, autoregressive and observation noise components, each of which are estimated using the particle filter algorithm. The spatial and temporal distributions of the extracted trend component clearly indicate high-risk regions, near which giant earthquakes have occurred or are predicted to occur. A multivariate analysis of the observatories located at the northeast coast of Japan successfully determines the past crustal displacement in the case of the 1978 Off-Miyagi Earthquake. The proposed method has the potential application for monitoring crustal activities related to the accumulation of earthquake energy. © 2012 The Author 2012.

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  • MCMC Algorithm to Estimate Physical Parameters of a Fracture from Tracer Tests Reviewed

    Nagao H, Sato K, Higuchi T

    Journal of the Japanese Association for Petroleum Technology   第78巻 ( 第2号 )   197 - 209   2013.3

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    A tracer test is a powerful experiment to identify fractures in underground reservoirs, which significantly affect fluid flow in a porous medium. The complex variable boundary element method (CVBEM) is capable of simulating time-series of the tracer concentration at a producer when the physical properties of the medium and the tracer injection plan are given. Several studies have proposed inversion procedures to identify physical parameters of a fracture in a homogeneous porous medium, using such as the genetic algorithm (GA) or the ensemble Kalman filter (EnKF) combined with iterative computations of CVBEM. The present paper proposes, for this inversion problem, a Markov chain Monte Carlo (MCMC) algorithm, which enables us to obtain a posterior probability density function (PDF) as well as an optimum value for each model parameter that characterizes the fracture. The proposed algorithm is performed to twin experiments that confirm whether properties of a synthetically-assumed fracture are reproduced from time-series of tracer concentration at a producer, which CVBEM has computed in advance. A clustering result of the K-means, which is applied to the samples obtained by MCMC, provides candidate solutions corresponding to local maximums of the posterior PDF. The candidate solutions are ranked by the posterior PDF at the centroid of each cluster. Especially in the case of the two-directional tracer test, in which two pairs of injector and producer are located, the optimum parameter set that maximizes the posterior PDF successfully reproduces both the fracture properties and the concentration curves.

    DOI: 10.3720/japt.78.197

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  • データ同化−モデルパラメータの分布推定−

    長尾 大道, 樋口 知之

    日本機械学会誌   Vol.116 ( No.1131 )   23 - 26   2013.2

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  • データ解析の神髄とは

    樋口 知之

    DIAMONDハーバード・ビジネス・レビュー   2013.2   98 - 108   2013.1

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  • Estimation of Abrupt Changes in Sentinel Observation Data of Influenza Epidemics in Japan Reviewed

    Masaya M. Saito, Seiya Imoto, Rui Yamaguchi, Satoru Miyano, Tomoyuki Higuchi

    2013 16TH INTERNATIONAL CONFERENCE ON INFORMATION FUSION (FUSION)   1385 - 1390   2013

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    Sentinel observations of influenza epidemic in each prefecture indicates basically unimodal trend but with irregular shocks, which are synchronous among prefectures. In this study, we have examined the possibility that the observed treads can be modeled by SIR with stochastic outer force added. The result shows that this is formally possible but large outer forces are needed in some prefecture.

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  • High Accuracy Spectrum Classification with Kernel Method

    ISHIGAKI Tsukasa, HIGUCHI Tomoyuki

    76 ( 12 )   741 - 743   2012.12

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  • 事例研究「状態空間モデルによるインターネット広告のクリック率予測 Reviewed

    本橋 永至, 磯崎 直樹, 長尾 大道, 樋口 知之

    オペレーションズ・リサーチ   Vol.57 ( No.10 )   574 - 583   2012.10

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  • Particle filter algorithm to analyze long-term tide gauge records for monitoring of the earth's crustal activities Reviewed

    Nagao H, Higuchi T, Miura S, Inazu D

    Journal of the japan statistical society   Vol.42 ( No.1 )   119 - 133   2012.9

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    The 140 tide gauge observatories located along the coastline of Japan have measured the sea levels for more than 100 years. A number of tide gauge records provide the information of the Earth's crustal activities associated with great earthquakes, e.g., the 2011 Great East Japan Earthquake, that occur periodically at the oceanic plate boundaries. The present paper develops an analysis procedure using the particle filter algorithm, which enables us to extract the crustal displacements from monthly means of the tide gauge records. The proposed method results that the plate boundary called "Nankai Trough" offshore west Japan has been rapidly accumulating the stress and strain energies, which will cause a great earthquake eventually. This result supports the hypothesis that the Tokai-Tonankai-Nankai Earthquake may occur in near future.

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  • ビッグデータと個人化技術

    樋口 知之

    月刊誌「統計」   9月号   2 - 9   2012.9

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  • Epidermal Growth Factor Receptor Tyrosine Kinase Defines Critical Prognostic Genes of Stage I Lung Adenocarcinoma Reviewed

    Mai Yamauchi, Rui Yamaguchi, Asuka Nakata, Takashi Kohno, Masao Nagasaki, Teppei Shimamura, Seiya Imoto, Ayumu Saito, Kazuko Ueno, Yousuke Hatanaka, Ryo Yoshida, Tomoyuki Higuchi, Masaharu Nomura, David G. Beer, Jun Yokota, Satoru Miyano, Noriko Gotoh

    PLOS ONE   7 ( 9 )   e43923   2012.9

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    Purpose: To identify stage I lung adenocarcinoma patients with a poor prognosis who will benefit from adjuvant therapy.
    Patients and Methods: Whole gene expression profiles were obtained at 19 time points over a 48-hour time course from human primary lung epithelial cells that were stimulated with epidermal growth factor (EGF) in the presence or absence of a clinically used EGF receptor tyrosine kinase (RTK)-specific inhibitor, gefitinib. The data were subjected to a mathematical simulation using the State Space Model (SSM). "Gefitinib-sensitive" genes, the expressional dynamics of which were altered by addition of gefitinib, were identified. A risk scoring model was constructed to classify high- or low-risk patients based on expression signatures of 139 gefitinib-sensitive genes in lung cancer using a training data set of 253 lung adenocarcinomas of North American cohort. The predictive ability of the risk scoring model was examined in independent cohorts of surgical specimens of lung cancer.
    Results: The risk scoring model enabled the identification of high-risk stage IA and IB cases in another North American cohort for overall survival (OS) with a hazard ratio (HR) of 7.16 (P = 0.029) and 3.26 (P = 0.0072), respectively. It also enabled the identification of high-risk stage I cases without bronchioalveolar carcinoma (BAC) histology in a Japanese cohort for OS and recurrence-free survival (RFS) with HRs of 8.79 (P = 0.001) and 3.72 (P = 0.0049), respectively.
    Conclusion: The set of 139 gefitinib-sensitive genes includes many genes known to be involved in biological aspects of cancer phenotypes, but not known to be involved in EGF signaling. The present result strongly re-emphasizes that EGF signaling status in cancer cells underlies an aggressive phenotype of cancer cells, which is useful for the selection of early-stage lung adenocarcinoma patients with a poor prognosis.

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  • Identifiability of local transmissibility parameters in agent-based pandemic simulation Reviewed

    Saito M, Imoto S, Yamaguchi R, Miyano S, Higuchi T

    Proceedings of 15th International Conference on Information Fusion   2466 - 2471   2012.7

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  • Weight adjustment of the particle filter on distributed computing systems Reviewed

    Nakano S, Higuchi T

    Proceedings of 15th International Conference on Information Fusion   2480 - 2485   2012.7

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  • Data assimilation of the earth's atmospheric and ionospheric oscillations excited by large earthquakes Reviewed

    Nagao H, Higuchi T

    Proceedings of 15th International Conference on Information Fusion   2472 - 2779   2012.7

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  • Classification of Road-Surface Condition by Tire Acceleration Waveform Analysis Based on HMM Reviewed

    HANATSUKA Yasushi, HIGUCHI Tomoyuki, MATSUI Tomoko

    The IEICE transactions on information and systems (Japanese edetion)   Vol.J95-D ( No.3 )   570 - 577   2012.3

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  • A High-Resolution Shape Fitting and Simulation Demonstrated Equatorial Cell Surface Softening during Cytokinesis and Its Promotive Role in Cytokinesis Reviewed

    Hiroshi Koyama, Tamiki Umeda, Kazuyuki Nakamura, Tomoyuki Higuchi, Akatsuki Kimura

    PLOS ONE   7 ( 2 )   e31607.   2012.2

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    Different models for animal cell cytokinesis posit that the stiffness of the equatorial cortex is either increased or decreased relative to the stiffness of the polar cortex. A recent work has suggested that the critical cytokinesis signaling complex centralspindlin may reduce the stiffness of the equatorial cortex by inactivating the small GTPase Rac. To determine if such a reduction occurs and if it depends on centralspindlin, we devised a method to estimate cortical bending stiffness with high spatio-temporal resolution from in vivo cell shapes. Using the early Caenorhabditis elegans embryo as a model, we show that the stiffness of the equatorial cell surface is reduced during cytokinesis, whereas the stiffness of the polar cell surface remains stiff. The equatorial reduction of stiffness was compromised in cells with a mutation in the gene encoding the ZEN-4/kinesin-6 subunit of centralspindlin. Theoretical modeling showed that the absence of the equatorial reduction of stiffness could explain the arrest of furrow ingression in the mutant. By contrast, the equatorial reduction of stiffness was sufficient to generate a cleavage furrow even without the constriction force of the contractile ring. In this regime, the contractile ring had a supportive contribution to furrow ingression. We conclude that stiffness is reduced around the equator in a centralspindlin-dependent manner. In addition, computational modeling suggests that proper regulation of stiffness could be sufficient for cleavage furrow ingression.

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  • Generating artistic character facial animation based on motion capture data Reviewed

    Hirose K, Higuchi T

    Proceedings of International Workshop on Advanced Image Technology   240 - 245   2012.1

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  • Parallel Agent-Based Simulator for Influenza Pandemic Reviewed

    Masaya M. Saito, Seiya Imoto, Rui Yamaguchi, Satoru Miyano, Tomoyuki Higuchi

    ADVANCED AGENT TECHNOLOGY   7068   361 - +   2012

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    We have developed a parallel agent-based influenza pandemic simulator, in order to study the influenza spread in a city. In the simulator, the city consists of several towns connected tightly by trains. Residents of the towns walk around places such as corporations and schools using trains by need, following to own schedulers. The influenza spread in these congested places is simulated as stochastic processes. We have demonstrated simulations with a realistic scale of population (an order of million) and showed that one simulation run is completed around one hour.

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  • Creating facial animation of characters via MoCap data Reviewed

    Kei Hirose, Tomoyuki Higuchi

    JOURNAL OF APPLIED STATISTICS   39 ( 12 )   2583 - 2597   2012

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    We consider the problem of generating 3D facial animation of characters. An efficient procedure is realized by using the motion capture data (MoCap data), which is obtained by tracking the facial markers from an actor/actress. In some cases of artistic animation, the MoCap actor/actress and the 3D character facial animation show different expressions. For example, from the original facial MoCap data of speaking, a user would like to create the character facial animation of speaking with a smirk. In this paper, we propose a new easy-to-use system for making character facial animation via MoCap data. Our system is based on the interpolation: once the character facial expressions of the starting and the ending frames are given, the intermediate frames are automatically generated by information from the MoCap data. The interpolation procedure consists of three stages. First, the time axis of animation is divided into several intervals by the fused lasso signal approximator. In the second stage, we use the kernel k-means clustering to obtain control points. Finally, the interpolation is realized by using the control points. The user can easily create a wide variety of 3D character facial expressions by changing the control points.

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  • Non-storm irregular variation of the D-st index Reviewed

    S. Nakano, T. Higuchi

    ANNALES GEOPHYSICAE   30 ( 1 )   153 - 162   2012

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    The D-st index has a long-term variation that is not associated with magnetic storms. We estimated the long-term non-storm component of the D-st variation by removing the short-term variation related to magnetic storms. The results indicate that the variation of the non-storm component includes not only a seasonal variation but also an irregular variation. The irregular long-term variation is likely to be due to an anti-correlation with the long-term variation of solar-wind activity. In particular, a clear anti-correlation is observed between the non-storm component of D-st and the long-term variation of the solar-wind dynamic pressure. This means that in the long term, the D-st index tends to increase when the solar-wind dynamic pressure decreases. We interpret this anti-correlation as an indication that the long-term non-storm variation of D-st is influenced by the tail current variation. The long-term variation of the solar-wind dynamic pressure controls the plasma sheet thermal pressure, and the change of the plasma sheet thermal pressure would cause the non-storm tail current variation, resulting in the non-storm variation of D-st.

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  • Modeling Human Behavior Selection under Environmental Subsidy Policy by Multi-agent Simulation Reviewed

    Tomoko Imoto, Shin'ya Nakano, Tomoyuki Higuchi

    ADVANCED AGENT TECHNOLOGY   7068   350 - 358   2012

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    In recent years. the importance of environment is widely recognized and various kinds of environmental policies have been implemented. However. when one establishes a policy, there are few cases that the contents and the period of the policy are evaluated by using prediction method for its effect. In this study, we aim to predict the effects of a policy in micro-level by using agent simulations and estimate the optimal period of the policy implementation by totally evaluating its effect. For sugarcane farmer of an area in Japan. we performed 200 thousand patterns of simulations in order to optimize the subsidy of green manure and its implementation period. In particular, when the values of the parameters in the simulation model are not clearly defined, we are able to show various futures caused by the policy implementation of interest based on large-scale simulations with a huge variety of the parameter values.

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  • A study of latitudinal dependence of Pc 3-4 amplitudes at 96° magnetic meridian stations in Africa Reviewed

    Takla EM, Yumoto K, Cardinal MG, Abe S, Fujimoto A, Ikeda A, Tokunaga T, Yamazaki Y, Uo-zumi T, Mahrous A, Ghamry E, Mengistu G, Afullo T, Macamo JA, Joao L, Mweene H, Mwiinga N, Uiso C, Baki P, Kianji G, Badi K, Sutcliffe P, Palangio P. Terumasa Tokunaga, Daisuke Ikeda, Kazuyuki Nakamura, Tomoyuki Higuchi, Akimasa Yoshikawa, Teiji Uozumi, Akiko Fujimoto, Akira Morioka, Kiyohumi Yumoto

    Sun and Geosphere   6 ( 2 )   65 - 70   2011.12

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  • Onset time determination of precursory events in time series data by an extension of Singular Spectrum Transformation Reviewed

    Tokunaga T, Ikeda D, Nakamura K, Higuchi T, Yoshikawa A, Uozumi T, Fujimoto A, Morioka A, Yumoto K

    International Journal of Circuits, Systems and Signal Processing   5 ( 1 )   46 - 60   2011.10

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    To predict an occurrence of extraordinary phenomena, such as earthquakes, failures of engineering systems and financial market crushes, it is important to identify precursory events in time series. However, existing methods are limited in their applicability for real world precursor detections. Recently, Ide and Inoue [1] have developed an SSA-based change-point detection method, called singular spectrum transformation (SST). SST is suitable for detecting various types of change-points, but real world precursor detections can be far more difficult than expected. In general, precursory events are observed as minute and less-visible fluctuations preceding an onset of massive fluctuations of extraordinary phenomena and therefore they are easily over-looked. To overcome this point, we extend the conventional SST to the multivariable SST. The originality of our strategy is in focusing on synchronism detections of precursory events in multiple sequences of univariate time series. We performed some experiments by using artificial data and showed the superiority of multivariable SST in detecting onset of precursory events. Furthermore, the superiority is also shown statistically in determi

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  • Solar wind driving of dayside field-aligned currents Reviewed

    Simon Wing, Shin-ichi Ohtani, Jay R. Johnson, Marius Echim, Patrick T. Newell, Tomoyuki Higuchi, Genta Ueno, Gordon R. Wilson

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   116   A08208   2011.8

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    Variations in the dayside field-aligned current (FAC) density (J(//)), field-aligned parallel potential drop (Delta phi(//)), peak precipitating electron energy (peak E(e)), and precipitating electron energy flux (epsilon) as functions of solar wind (SW) and interplanetary magnetic field (IMF) are investigated with Defense Meteorological Satellite Program observations and a quasi-stationary low-latitude boundary layer (LLBL)-FAC coupling model. Region 1 (R1) J(//) responses to variations in SW velocity (V(sw)) and density (n(sw)) at 8-16 magnetic local time (MLT) suggest that R1 at these local times is frequently open while R1 at 6-08 and 17-18 MLT is frequently closed. R2 is located mostly on closed field lines. In the afternoon open R1 at 12-16 MLT, an increase in n(sw) increases J(//), decreases maximum peak Ee (proxy for Delta phi(//)), but has little effect on maximum epsilon. In the same R1 region, an increase in V(sw) increases J(//), maximum peak E(e), and maximum epsilon. The dependencies of J(//), maximum peak E(e), and maximum epsilon are consistent with the Knight relation and the voltage generator at the magnetopause boundary in the afternoon open R1. In the midmorning and midafternoon, the response of J(//) to V(sw) is higher for southward than for northward IMF. This can be attributed to the higher-velocity shear at the magnetopause boundary due to higher sunward convection in the LLBL inside the magnetopause. R1 in the closed-field lines near dawn and dusk appears to be more sensitive to merging rate (d Phi/dt = V(4/3)(sw) B(T)(2/3) sin(8/3)(theta(c)/2)) than to SW dynamic pressure.

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  • An algorithm for detecting precursory events from time series data Reviewed

    Tokunaga T, Ikeda D, Nakamura K, Higuchi T, Yoshikawa A, Uozumi T, Fujimoto A, Morioka A, Yumoto K

    Information Processing Society of Japan   Vol. 4 ( No. 3 )   14 - 34   2011.7

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  • Effect prediction and comparison of agricultural environmental policies by agent simulations Reviewed

    Imoto T, Nakano S, Higuchi T

    Japanese journal of food, agricultural and resource economics   第6巻 ( 第1号 )   89 - 101   2011.7

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  • Estimation of macroscopic parameter in agent-based pandemic simulation Reviewed

    Saitoh M, Imoto S, Yamaguchi R, Miyano S, Higuchi T

    Proceedings of 14th International Conference Fusion   2011.7

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  • Fault parameter estimation with data assimilation on infrasound variations due to big earthquakes Reviewed

    Nagao H, Kobayashi N, Nakano S, Higuchi T

    Proceedings of 14th International Conference Fusion   2011.7

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  • Embedding reality in a numerical simulation with data assimilation Reviewed

    Higuchi T

    Proceedings of 14th International Conference Fusion   2011.7

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  • Displacement of conjugate points during a substorm in a global magnetohydrodynamic simulation Reviewed

    S. Saita, A. Kadokura, N. Sato, S. Fujita, T. Tanaka, Y. Ebihara, S. Ohtani, G. Ueno, K. Murata, D. Matsuoka, A. Kitamoto, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   116   A06213   2011.6

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    We reproduce a magnetospheric reconfiguration under southward interplanetary magnetic field (IMF) conditions using numerical magnetohydrodynamic simulations. To investigate the relative displacements of the geomagnetic conjugate points, we trace both footprints of the geomagnetic field lines during the magnetospheric reconfiguration under positive and negative IMF B-y conditions. Several substormlike features, namely, the formation of a near-Earth neutral line, a fast earthward flow, and tailward releases of the plasmoid, occur about 1 h after a southward turning of the IMF. The surveyed field line traced from the near-Earth magnetotail was strongly distorted duskward in the north and south after the substorm onset for positive and negative IMF B-y, respectively. The maximum of the relative longitudinal displacement of both footprints is 4.5 and 5.5 h in magnetic local time for positive and negative IMF B-y, respectively. While observational studies have indicated that the IMF orientation is the main factor controlling the relative displacement of the conjugate points, the present simulation-based study with a constant IMF orientation shows for the first time that the combined effects of plasma pressure, magnetic field intensity, and the field-aligned current density distribution along the field line are likely to be major factors controlling the relative displacement of conjugate points.

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  • Dynamic Brand Choice Modeling Based on the State-space Approach Reviewed

    Eiji Motohashi, Tomoyuki Higuchi

    Data Mining for Marketing   48-54   2011.4

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  • Displacement of conjugate points during a substorm in a global magnetohydrodynamic simulation Reviewed

    S. Saita, A. Kadokura, N. Sato, S. Fujita, T. Tanaka, Y. Ebihara, S. Ohtani, G. Ueno, K. Murata, D. Matsuoka, A. Kitamoto, T. Higuchi

    Journal of Geophysical Research: Space Physics   116 ( 6 )   2011

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    We reproduce a magnetospheric reconfiguration under southward interplanetary magnetic field (IMF) conditions using numerical magnetohydrodynamic simulations. To investigate the relative displacements of the geomagnetic conjugate points, we trace both footprints of the geomagnetic field lines during the magnetospheric reconfiguration under positive and negative IMF By conditions. Several substormlike features, namely, the formation of a near-Earth neutral line, a fast earthward flow, and tailward releases of the plasmoid, occur about 1 h after a southward turning of the IMF. The surveyed field line traced from the near-Earth magnetotail was strongly distorted duskward in the north and south after the substorm onset for positive and negative IMF By, respectively. The maximum of the relative longitudinal displacement of both footprints is 4.5 and 5.5 h in magnetic local time for positive and negative IMF By, respectively. While observational studies have indicated that the IMF orientation is the main factor controlling the relative displacement of the conjugate points, the present simulation-based study with a constant IMF orientation shows for the first time that the combined effects of plasma pressure, magnetic field intensity, and the field-aligned current density distribution along the field line are likely to be major factors controlling the relative displacement of conjugate points. Copyright 2011 by the American Geophysical Union.

    DOI: 10.1029/2010JA016155

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  • Solar wind driving of dayside field-aligned currents Reviewed

    Simon Wing, Shin-Ichi Ohtani, Jay R. Johnson, Marius Echim, Patrick T. Newell, Tomoyuki Higuchi, Genta Ueno, Gordon R. Wilson

    Journal of Geophysical Research: Space Physics   116 ( 8 )   2011

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    Variations in the dayside field-aligned current (FAC) density (J //), field-aligned parallel potential drop (δφ //), peak precipitating electron energy (peak Ee), and precipitating electron energy flux (ε) as functions of solar wind (SW) and interplanetary magnetic field (IMF) are investigated with Defense Meteorological Satellite Program observations and a quasi-stationary low-latitude boundary layer (LLBL)-FAC coupling model. Region 1 (R1) J// responses to variations in SW velocity (Vsw) and density (nsw) at 8-16 magnetic local time (MLT) suggest that R1 at these local times is frequently open while R1 at 6-08 and 17-18 MLT is frequently closed. R2 is located mostly on closed field lines. In the afternoon open R1 at 12-16 MLT, an increase in nsw increases J//, decreases maximum peak Ee (δφ//), but has little effect on maximum ε. In the same R1 region, an increase in Vsw increases J//, maximum peak Ee, and maximum ε. The dependencies of J//, maximum peak Ee, and maximum ε are consistent with the Knight relation and the voltage generator at the magnetopause boundary in the afternoon open R1. In the midmorning and midafternoon, the response of J// to Vsw is higher for southward than for northward IMF. This can be attributed to the higher-velocity shear at the magnetopause boundary due to higher sunward convection in the LLBL inside the magnetopause. R1 in the closed-field lines near dawn and dusk appears to be more sensitive to merging rate (dΦ/dt = Vsw4/3 BT2/3 sin8/3(θc/2)) than to SW dynamic pressure. Copyright 2011 by the American Geophysical Union.

    DOI: 10.1029/2011JA016579

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  • Dayside field-aligned current source regions Reviewed

    Simon Wing, Shin-ichi Ohtani, Patrick T. Newell, Tomoyuki Higuchi, Genta Ueno, James M. Weygand

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115   2010.12

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    The source regions of region-0 (R0), region-1 (R1), and region-2 (R2) field-aligned currents (FACs) were statistically determined using DMSP particle precipitation and magnetometer data. Each FAC sheet originates from more than one region in the magnetosphere, depending on the latitude and the magnetic local time (MLT). R2 originates mostly from the central plasma sheet (CPS) and boundary plasma sheet (BPS) in the morning and from the CPS, BPS, and inner magnetosphere in the afternoon, all of which are on closed field lines. Near noon, some R2 may originate from the low-latitude boundary layer (LLBL), which is located near the magnetopause and can be open or closed. R1 mostly maps to the BPS, hence on closed field lines, in morning and afternoon, but near noon, it maps mostly to the LLBL. The LLBL source region can be found more frequently in the dawn-noon sector than in the noon-dusk sector. On the other hand, R0 is located mostly on open field lines and is associated mostly with mantle precipitation. However, the mantle precipitation has a dependency on the polarity of R0. Within up-flowing R0, sometimes an upward field-aligned electric field, which accelerates electron downward and retards ion precipitation, modifies mantle distribution to look more like those of polar rain or BPS. This electric field has the opposite polarity to the background electric field that maintains charge-quasi-neutrality and that limits some solar wind electrons from entering the magnetosphere in the mantle and polar rain regions. Implications to current generation mechanisms are discussed.

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  • Locations of night-side precipitation boundaries relative to R2 and R1 currents Reviewed

    S. Ohtani, S. Wing, P. T. Newell, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   115 ( A10233 )   2010.10

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    The present study statistically examines the location of various precipitation boundaries introduced by Newell et al. (1996) relative to R2 and R1 currents on the night side. Results are summarized as follows: (1) The electron and ion zero-energy boundaries, b1e and b1i, are located mostly inside the R2 current at dusk-to-midnight and near the equatorward boundary of the R2 current or farther equatorward at midnight-to-dawn. (2) The maximum energy flux of ion precipitation (b2i) occurs inside the R2 current irrespective of magnetic local time. (3) The occurrence distributions of the most equatorward (b3a) and poleward (b3b) electron acceleration events indicate that mono-energetic electron precipitation is mostly confined in the upward R1 current at dusk-to-midnight, whereas at midnight-to-dawn, it is more widely distributed including the downward R1 current. (4) The transition between structured and unstructured electron precipitation (b4s) tends to occur around the R2/R1 demarcation, but its occurrence distribution has extending tails. (5) The distributions of the poleward boundaries of the electron and ion auroral ovals, b5e and b5i, are centered around the poleward boundary of the R1 current but have extending tails especially at midnight-to-dawn. Result 1 suggests that the overlap between the ring current and the plasmasphere is more significant at dusk than at dawn. Result 2 indicates that the b2i boundary can be used as an identifier of the R2 current. Results 3-5 suggest that the R1 current is more structured than the R2 current and that the field-aligned current structure is more complex at midnight-to-dawn than at dusk-to-midnight.

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  • Fault detection of a vibration mechanism by spectrum classification with a divergence-based kernel Reviewed

    T. Ishigaki, T. Higuchi, K. Watanabe

    IET SIGNAL PROCESSING   4 ( 5 )   518 - 529   2010.10

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    The present study describes a frequency spectrum classification method for fault detection of the LP gas pressure regulator using support vector machines (SVMs). Conventional diagnosis methods are inefficient because of problems such as significant noise and non-linearity of the detection mechanism. In order to address these problems, a machine learning method with a divergence-based kernel is introduced into spectrum classification. The authors use the normalised frequency spectrum directly as input with the divergence-based kernel. The proposed method is applied to the vibration spectrum classification of the rubber diaphragm in a pressure regulator. As a result, the classification performance using the divergence-based kernel is shown to be better than when using common kernels such as the Gaussian kernel or the polynomial kernel. The high classification performance is achieved by using an inexpensive sensor system and the machine learning method. The proposed method is widely applicable to other spectrum classification applications without limitation on the generality if the spectra are normalised.

    DOI: 10.1049/iet-spr.2008.0195

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  • Special section on data mining and statistical science Reviewed

    Masashi Sugiyama, Tomoyuki Higuchi, Tsuyoshi Ide, Akihiro Inokuchi, Toshihiro Kamishima, Hiroyuki Minami, Shinichi Nakajima, Atsuyoshi Nakamura, Koichi Shinoda, Koji Tsuda, Takashi Washio

    IEICE Transactions on Information and Systems   E93-D ( 10 )   2671   2010.10

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  • Bayesian experts in exploring reaction kinetics of transcription circuits Reviewed

    Ryo Yoshida, Masaya M. Saito, Hiromichi Nagao, Tomoyuki Higuchi

    BIOINFORMATICS   26 ( 18 )   i589 - i595   2010.9

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    Motivation Biochemical reactions in cells are made of several types of biological circuits. In current systems biology, making differential equation ( DE) models simulatable in silico has been an appealing, general approach to uncover a complex world of biochemical reaction dynamics. Despite of a need for simulation-aided studies, our research field has yet provided no clear answers: how to specify kinetic values in models that are difficult to measure from experimental/theoretical analyses on biochemical kinetics.
    Results: We present a novel non-parametric Bayesian approach to this problem. The key idea lies in the development of a Dirichlet process (DP) prior distribution, called Bayesian experts, which reflects substantive knowledge on reaction mechanisms inherent in given models and experimentally observable kinetic evidences to the subsequent parameter search. The DP prior identifies significant local regions of unknown parameter space before proceeding to the posterior analyses. This article reports that a Bayesian expert-inducing stochastic search can effectively explore unknown parameters of in silico transcription circuits such that solutions of DEs reproduce transcriptomic time course profiles.

    DOI: 10.1093/bioinformatics/btq389

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  • Bayesian experts in exploring reaction kinetics of transcription circuits Reviewed

    Ryo Yoshida, Masaya M. Saito, Hiromichi Nagao, Tomoyuki Higuchi

    BIOINFORMATICS   26 ( 18 )   i589 - i595   2010.9

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    Motivation Biochemical reactions in cells are made of several types of biological circuits. In current systems biology, making differential equation ( DE) models simulatable in silico has been an appealing, general approach to uncover a complex world of biochemical reaction dynamics. Despite of a need for simulation-aided studies, our research field has yet provided no clear answers: how to specify kinetic values in models that are difficult to measure from experimental/theoretical analyses on biochemical kinetics.
    Results: We present a novel non-parametric Bayesian approach to this problem. The key idea lies in the development of a Dirichlet process (DP) prior distribution, called Bayesian experts, which reflects substantive knowledge on reaction mechanisms inherent in given models and experimentally observable kinetic evidences to the subsequent parameter search. The DP prior identifies significant local regions of unknown parameter space before proceeding to the posterior analyses. This article reports that a Bayesian expert-inducing stochastic search can effectively explore unknown parameters of in silico transcription circuits such that solutions of DEs reproduce transcriptomic time course profiles.

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  • A Multivariable Detection Device Based on a Capacitive Microphone and Its Application to Security Reviewed

    Kajiro Watanabe, Tsukasa Ishigaki, Tomoyuki Higuchi

    IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT   59 ( 7 )   1955 - 1963   2010.7

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    Any sensor for detecting a certain physical variable is more or less influenced by other physical variables, which are designated as "noise." The objective in conventional sensor design has been to minimize the noise. In this paper, however, we make use of sensing devices that are easily influenced by multiple physical variables andmake full use of their multisensing characteristic. We consider such devices as multiple-input-single-output sensors. First, the output signal derived from multiple input signals must be dissociated. The input signals resulting from physical phenomena have inherent characteristics and can mathematically be modeled. Application of a Kalman filter realized by such models can provide estimates of the state variables of all input models, and thus, the input signals are dissociated. As an example, a novel sensor based on a microphone is presented. This sensor can detect various variables such as pressure and acceleration in the frequency range of 0.1 Hz to 10 kHz, temperature, and even light emission. We apply the sensor to monitor the symptoms of fire, earthquake, and break-in by an intruder from within a house.

    DOI: 10.1109/TIM.2009.2030716

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  • Web application for time-series analysis based on particle filter available on cloud computing system Reviewed

    Nagao, H, T. Higuchi

    The Proceedings of 13th International Conference on Information Fusion   2010.7

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    DOI: 10.1109/ICIF.2010.5712015

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  • Maximum likelihood estimation of error covariances in ensemble-based filters and its application to a coupled atmosphere-ocean model Reviewed

    Genta Ueno, Tomoyuki Higuchi, Takashi Kagimoto, Naoki Hirose

    QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY   136 ( 650 )   1316 - 1343   2010.7

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    We propose a method for estimating optimal error covariances in the context of sequential assimilation, including the case where both the system equation and the observation equation are nonlinear. When the system equation is nonlinear, ensemble-based filtering methods such as the ensemble Kalman filter (EnKF) are widely used to deal directly with the nonlinearity. The present approach for covariance optimization is a maximum likelihood estimation carried out by approximating the likelihood with the ensemble mean. Specifically, the likelihood is approximated as the sample mean of the likelihood of each member of the ensemble. To evaluate the sampling error of the proposed ensemble-approximated likelihood, we construct a method for examining the statistical significance using the bootstrap method without extra ensemble computation. We apply the proposed methods to an EnKF experiment where TOPEX/POSEIDON altimetry observations are assimilated into an intermediate coupled model, which is nonlinear, and estimate the optimal parameters that specify the covariances of the system noise and observation noise. Using these optimal covariance parameters, we examine the estimates by the EnKF and the ensemble Kalman smoother (EnKS). The effect of smoothing decreases by 1/e approximately one year after the filtering step. One of the properties of the smoothed estimate is that westerly wind anomalies over the western Pacific are not reproduced around the period of an El Nino event, while those over the central Pacific are strengthened. From additional experiments, we find that (1) the westerly winds in the western Pacific are phenomena outside of the coupled model and are not necessary to model El Nino, (2) the model El Nino is maintained by the westerlies over the central Pacific, and (3) the modelled evolution process of the sea-surface temperature (SST) requires improvement to reproduce the westerly winds over the western Pacific. Copyright (C) 2010 Royal Meteorological Society

    DOI: 10.1002/qj.654

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  • A state space representation of VAR models with sparse learning for dynamic gene networks. Reviewed

    Kojima K, Yamaguchi R, Imoto S, Yamauchi M, Nagasaki M, Yoshida R, Shimamura T, Ueno K, Higuchi T, Gotoh N, Miyano S

    Genome informatics. International Conference on Genome Informatics   22   56 - 68   2010.1

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    We propose a state space representation of vector autoregressive model and its sparse learning based on L1 regularization to achieve efficient estimation of dynamic gene networks based on time course microarray data. The proposed method can overcome drawbacks of the vector autoregressive model and state space model; the assumption of equal time interval and lack of separation ability of observation and systems noises in the former method and the assumption of modularity of network structure in the latter method. However, in a simple implementation the proposed model requires the calculation of large inverse matrices in a large number of times during parameter estimation process based on EM algorithm. This limits the applicability of the proposed method to a relatively small gene set. We thus introduce a new calculation technique for EM algorithm that does not require the calculation of inverse matrices. The proposed method is applied to time course microarray data of lung cells treated by stimulating EGF receptors and dosing an anticancer drug, Gefitinib. By comparing the estimated network with the control network estimated using non-treated lung cells, perturbed genes by the anticancer drug could be found, whose up- and down-stream genes in the estimated networks may be related to side effects of the anticancer drug.

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  • Locations of night-side precipitation boundaries relative to R2 and R1 currents Reviewed

    S. Ohtani, S. Wing, P. T. Newell, T. Higuchi

    Journal of Geophysical Research: Space Physics   115 ( 10 )   2010

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    The present study statistically examines the location of various precipitation boundaries introduced by Newell et al. (1996) relative to R2 and R1 currents on the night side. Results are summarized as follows: (1) The electron and ion zero-energy boundaries, b1e and b1i, are located mostly inside the R2 current at dusk-to-midnight and near the equatorward boundary of the R2 current or farther equatorward at midnight-to-dawn. (2) The maximum energy flux of ion precipitation (b2i) occurs inside the R2 current irrespective of magnetic local time. (3) The occurrence distributions of the most equatorward (b3a) and poleward (b3b) electron acceleration events indicate that mono-energetic electron precipitation is mostly confined in the upward R1 current at dusk-to-midnight, whereas at midnight-to-dawn, it is more widely distributed including the downward R1 current. (4) The transition between structured and unstructured electron precipitation (b4s) tends to occur around the R2/R1 demarcation, but its occurrence distribution has extending tails. (5) The distributions of the poleward boundaries of the electron and ion auroral ovals, b5e and b5i, are centered around the poleward boundary of the R1 current but have extending tails especially at midnight-to-dawn. Result 1 suggests that the overlap between the ring current and the plasmasphere is more significant at dusk than at dawn. Result 2 indicates that the b2i boundary can be used as an identifier of the R2 current. Results 3-5 suggest that the R1 current is more structured than the R2 current and that the field-aligned current structure is more complex at midnight-to-dawn than at dusk-to-midnight. Copyright 2010 by the American Geophysical Union.

    DOI: 10.1029/2010JA015444

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  • Dayside field-aligned current source regions Reviewed

    Simon Wing, Shin-Ichi Ohtani, Patrick T. Newell, Tomoyuki Higuchi, Genta Ueno, James M. Weygand

    Journal of Geophysical Research: Space Physics   115 ( 12 )   2010

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    The source regions of region-0 (R0), region-1 (R1), and region-2 (R2) field-aligned currents (FACs) were statistically determined using DMSP particle precipitation and magnetometer data. Each FAC sheet originates from more than one region in the magnetosphere, depending on the latitude and the magnetic local time (MLT). R2 originates mostly from the central plasma sheet (CPS) and boundary plasma sheet (BPS) in the morning and from the CPS, BPS, and inner magnetosphere in the afternoon, all of which are on closed field lines. Near noon, some R2 may originate from the low-latitude boundary layer (LLBL), which is located near the magnetopause and can be open or closed. R1 mostly maps to the BPS, hence on closed field lines, in morning and afternoon, but near noon, it maps mostly to the LLBL. The LLBL source region can be found more frequently in the dawn-noon sector than in the noon-dusk sector. On the other hand, R0 is located mostly on open field lines and is associated mostly with mantle precipitation. However, the mantle precipitation has a dependency on the polarity of R0. Within up-flowing R0, sometimes an upward field-aligned electric field, which accelerates electron downward and retards ion precipitation, modifies mantle distribution to look more like those of polar rain or BPS. This electric field has the opposite polarity to the background electric field that maintains charge-quasi-neutrality and that limits some solar wind electrons from entering the magnetosphere in the mantle and polar rain regions. Implications to current generation mechanisms are discussed. Copyright 2010 by the American Geophysical Union.

    DOI: 10.1029/2010JA015837

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  • A dynamic grouping strategy for implementation of the particle filter on a massively parallel computer Reviewed

    S. Nakano, T. Higuchi

    Proceedings of the 13th International Conference on Information Fusion   2010

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    DOI: 10.1109/ICIF.2010.5712049

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  • A new particle filter for high-dimensional state-space models based on intensive and extensive proposal distribution.

    Viet Phuong Nguyen, Takashi Washio, Tomoyuki Higuchi

    International Journal of Knowledge Engineering and Soft Data Paradigms   2 ( 4 )   284 - 311   2010

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    DOI: 10.1504/IJKESDP.2010.037492

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  • Detecting Precursory Events in Time Series Data by an Extension of Singular Spectrum Transformation Reviewed

    Terumasa Tokunaga, Tomoyuki Higuchi, Akiko Fujimoto, Daisuke Ikeda, Akimasa Yoshikawa, Akira Morioka, Kazuyuki Nakamura, Teiji Uozumi, Kiyofumi Yumoto

    SELECTED TOPICS IN APPLIED COMPUTER SCIENCE   366 - +   2010

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:WORLD SCIENTIFIC AND ENGINEERING ACAD AND SOC  

    To predict an occurrence of extraordinary phenomena, such as earthquakes, failures of engineering system and financial market crushes, it is important to identify precursory events in time series. However, existing methods are limited in their applicability for real world precursor detections. Recently, Ide and Inoue [1] have developed an SSA-based change-point detection method, called singular spectrum transformation (SST). In this paper, we extend the SST so that it is applicable for real world precursor detections, focusing on the wide applicability of the conventional SST. Although the SST is suitable for detecting various types of change-points, detecting precursors can be far more difficult than expected because, in general, real world time series contains measurement noise and non-stationary trends. Furthermore, precursory events are usually observed as minute and less-visible fluctuations preceding an onset of massive fluctuations of extraordinary phenomena and therefore they are easily over-looked. To overcome this, we extend the conventional SST to the multivariable SST, focusing on the synchronism detection of precursory events in multiple sequences of univariate time series. First, we would like to define the problem setting of real world precursory detections and consider its difficulties. Second, the multivariable SST is introduced. Third, we apply SST to geomagnetic time series data and show the multivariable SST is more suitable than the conventional SST for real world precursor detections. Finally, we show further experimental results using artificial data to evaluate the reliability of SST-based precursor detections.

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  • Optimization of boundary condition and physical parameter in an ocean tide model using an evolutionary algorithm Reviewed

    Inazu D, Higuchi T, Nakamura K

    Theoretical and Applied Mechanics Japan   58   101 - 112   2010

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    DOI: 10.11345/nctam.58.101

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  • Dependence of premidnight field-aligned currents and particle precipitation on solar illumination Reviewed

    S. Ohtani, S. Wing, G. Ueno, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   114   2009.12

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    The present study statistically addresses the dependence of large-scale field-aligned currents (R1/R2) and particle precipitation in the premidnight sector on solar illumination at the ionosphere. The energy flux and average energy of precipitating electrons and ions are examined for downward R2 and upward R1 currents. Results are summarized as follows: (1) The R1 current density is larger in the dark hemisphere, whereas the dependence of R2 density on solar illumination is unclear. (2) For R1 currents the electron energy flux is larger and the average electron energy is higher in the dark hemisphere. (3) For R2 currents, a similar preference for the dark hemisphere is found for the electron energy flux, which, however, is significantly lower than for R1 currents. The average electron energy is similar between the two hemispheres. (4) For both R1 and R2 currents, ion precipitation is more intense and energetic in the dark hemisphere. (5) For a given field-aligned current density, whether R1 or R2 currents, both electron and ion precipitation is more intense and energetic in the dark hemisphere. The Pedersen conductivity is estimated from electron precipitation and solar illumination. The result suggests that in the dark hemisphere the absence of solar illumination is often overcompensated by more intense and energetic electron precipitation. The interhemispheric difference in electron acceleration may be interpreted in terms of plasma density in the acceleration region, which is known to be significantly lower in the dark hemisphere, and therefore electrons need to be more accelerated along the field line to carry imposed currents.

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  • Estimation of a Long-Term Variation of a Magnetic-Storm Index Using the Merging Particle Filter Reviewed

    Shin'ya Nakano, Tomoyuki Higuchi

    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS   E92D ( 7 )   1382 - 1387   2009.7

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    The D(st) index is the most popular measure of a scale of magnetic storms, and it is widely used as a monitor of the conditions of the Earth's magnetosphere. Since the D(st) index contains contributions from multiple magnetospheric phenomena, it is important to distinguish each of the contributions in order to obtain meaningful information about the conditions of the magnetosphere. There have been several efforts which modeled temporal evolution of the D(st) index empirically. and these empirical models considers some contributions separately. However, they take only short-term varations into accout, and contributions from phenomena which show long-term variations are neglected. In the present study, we have developed a technique for estimating the component of long-term variations of the D(st) index using solar wind data and a nonlinear empirical model. The newly-developed technique adopts an algorithm which is similar to the particle filter. This algorithm allows an on-line processing of a long sequence of D(st) data, which would enable a real-time estimation of system variables in a nonlinear system model. The estimates of the long-term variations can be used for accurate estimation of other contributions to the D(st) index, which would provide credible information about the conditions of the magnetosphere. The framework proposed in the present study could be applied for the purpose of continuous real-time monitoring of the environment of the magnetosphere.

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  • Accurate ocean tide modeling in southeast Alaska and large tidal dissipation around Glacier Bay Reviewed

    Daisuke Inazu, Tadahiro Sato, Satoshi Miura, Yusaku Ohta, Kazuyuki Nakamura, Hiromi Fujimoto, Christopher F. Larsen, Tomoyuki Higuchi

    JOURNAL OF OCEANOGRAPHY   65 ( 3 )   335 - 347   2009.6

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    An accurate prediction of ocean tides in southeast Alaska is developed using a regional, barotropic ocean model with a finite difference scheme. The model skill is verified by the observational tidal harmonics in southeast Alaska including Glacier Bay. The result is particularly improved in Glacier Bay compared to the previous model described by Foreman et al. (2000). The model bathymetry dominates the model skill. We re-estimate tidal energy dissipation in the Alaska Panhandle and suggest a value for tidal energy dissipation of 3.4 GW associated with the M(2) constituent which is 1.5 times the estimation of Foreman et al. (2000). A large portion of the M(2) energy budget entering through Chatham Strait is dissipated in the vicinity of Glacier Bay. Moreover, it is shown that the developed model has the potential to correct the ocean tide loading effect in geodetic data more efficiently than the model of Foreman et al. (2000), especially around Glacier Bay.

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  • 細胞内生化学反応経路のグラフィカルモデリングと統計的推測手法の新展開 Reviewed

    吉田 亮, 樋口 知之

    日本統計学会誌   Vol.38 ( No.2 )   213 - 236   2009.3

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  • Impact of the solar wind dynamic pressure on the Region 2 field-aligned currents Reviewed

    S. Nakano, G. Ueno, S. Ohtani, T. Higuchi

    Journal of Geophysical Research: Space Physics   114 ( 2 )   2009.2

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    The relationship between the Region 2 field-aligned currents and the solar wind dynamic pressure is investigated using magnetic field data from Defense Meteorological Satellite Program-F13 (DMSP-F13). The generation of the Region 2 currents is associated with the direction of the magnetic pressure gradient in the magnetosphere, in relation to that of the thermal pressure gradient. Past spacecraft observations have suggested that the spatial distribution of the magnetic pressure in the magnetosphere varies with the solar wind dynamic pressure. Therefore, we can expect that the Region 2 currents would depend on the solar wind dynamic pressure. We compared the Region 2 field-aligned current intensity at the altitude of the ionosphere, as derived using magnetic field data from DMSP-F13, with the solar wind dynamic pressure derived from 0MNI2 hourly data. It was confirmed that the Region 2 current intensity depends on the solar wind dynamic pressure during magnetic storms. During nonstorm times, however, the correlation between the Region 2 currents and the solar wind dynamic pressure is weak. The weak correlation during nonstorm times suggests that the plasma pressure in the ring current region is also essential for the effect of the solar wind dynamic pressure on the Region 2 currents. © 2009.

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  • 動的個人モデルによる購買生起行動の解析 Reviewed

    佐藤 忠彦, 樋口 知之

    マーケティング・サイエンス   Vol.16 ( No.1・2 )   49 - 73   2009.2

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  • Impact of the solar wind dynamic pressure on the Region 2 field-aligned currents Reviewed

    S. Nakano, G. Ueno, S. Ohtani, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   114   A02221   2009.2

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    The relationship between the Region 2 field-aligned currents and the solar wind dynamic pressure is investigated using magnetic field data from Defense Meteorological Satellite Program-F13 (DMSP-F13). The generation of the Region 2 currents is associated with the direction of the magnetic pressure gradient in the magnetosphere, in relation to that of the thermal pressure gradient. Past spacecraft observations have suggested that the spatial distribution of the magnetic pressure in the magnetosphere varies with the solar wind dynamic pressure. Therefore, we can expect that the Region 2 currents would depend on the solar wind dynamic pressure. We compared the Region 2 field-aligned current intensity at the altitude of the ionosphere, as derived using magnetic field data from DMSP-F13, with the solar wind dynamic pressure derived from OMNI2 hourly data. It was confirmed that the Region 2 current intensity depends on the solar wind dynamic pressure during magnetic storms. During nonstorm times, however, the correlation between the Region 2 currents and the solar wind dynamic pressure is weak. The weak correlation during nonstorm times suggests that the plasma pressure in the ring current region is also essential for the effect of the solar wind dynamic pressure on the Region 2 currents.

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  • 粒子フィルタによる地盤解析のデータ同化 Reviewed

    村上 章, 西村 伸一, 藤澤 和謙, 中村 和幸, 樋口 知之

    応用力学論文集   12   99 - 105   2009

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  • Particle filtering in data assimilation and its application to boundary condition of tsunami simulation model Reviewed

    Nakamura K, Hirose N, Choi B.H Y, Higuchi T

    Data Assimilation for Atmospheric, Oceanic and Hydrologic Applications   353 - 366   2009

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  • Dynamic spectrum classification by Kernel classifiers with divergence-based Kernels and its applications to acoustic signals Reviewed

    Ishigaki T, Higuchi T

    International Journal of Knowledge Engineering and Soft Data Paradigms   1873 - 1876   2009

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  • PARAMETER ESTIMATION OF IN SILICO BIOLOGICAL PATHWAYS WITH PARTICLE FILTERING TOWARDS A PETASCALE COMPUTING Reviewed

    Kazuyuki Nakamura, Ryo Yoshida, Masao Nagasaki, Satoru Miyano, Tomoyuki Higuchi

    PACIFIC SYMPOSIUM ON BIOCOMPUTING 2009   227 - +   2009

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    The aim of this paper is to demonstrate the potential power of large-scale particle filtering for the parameter estimations of in silico biological pathways where time course measurements of biochemical reactions are observable. The method of particle filtering has been a popular technique in the field of statistical science, which approximates posterior distributions of model parameters of dynamic system by using sequentially-generated Monte Carlo samples. In order to apply the particle filtering to system identifications of biological pathways, it is often needed to explore the posterior distributions which are defined over an exceedingly high-dimensional parameter space. It is then essential to use a fairly large amount of Monte Carlo samples to obtain an approximation with a high-degree of accuracy. In this paper, we address some implementation issues on large-scale particle filtering, and then, indicate the importance of large-scale computing for parameter learning of in silico biological pathways. We have tested the ability of the particle filtering with 10(8) Monte Carlo samples on the transcription circuit of circadian clock that contains 45 unknown kinetic parameters. The proposed approach could reveal clearly the shape of the posterior distributions over the 45 dimensional parameter space.

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  • PARAMETER ESTIMATION OF IN SILICO BIOLOGICAL PATHWAYS WITH PARTICLE FILTERING TOWARDS A PETASCALE COMPUTING Reviewed

    Kazuyuki Nakamura, Ryo Yoshida, Masao Nagasaki, Satoru Miyano, Tomoyuki Higuchi

    PACIFIC SYMPOSIUM ON BIOCOMPUTING 2009   227 - +   2009

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    The aim of this paper is to demonstrate the potential power of large-scale particle filtering for the parameter estimations of in silico biological pathways where time course measurements of biochemical reactions are observable. The method of particle filtering has been a popular technique in the field of statistical science, which approximates posterior distributions of model parameters of dynamic system by using sequentially-generated Monte Carlo samples. In order to apply the particle filtering to system identifications of biological pathways, it is often needed to explore the posterior distributions which are defined over an exceedingly high-dimensional parameter space. It is then essential to use a fairly large amount of Monte Carlo samples to obtain an approximation with a high-degree of accuracy. In this paper, we address some implementation issues on large-scale particle filtering, and then, indicate the importance of large-scale computing for parameter learning of in silico biological pathways. We have tested the ability of the particle filtering with 10(8) Monte Carlo samples on the transcription circuit of circadian clock that contains 45 unknown kinetic parameters. The proposed approach could reveal clearly the shape of the posterior distributions over the 45 dimensional parameter space.

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  • Dependence of premidnight field-aligned currents and particle precipitation on solar illumination Reviewed

    S. Ohtani, S. Wing, G. Ueno, T. Higuchi

    Journal of Geophysical Research: Space Physics   114 ( 12 )   2009

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    The present study statistically addresses the dependence of large-scale field-aligned currents (R1/R2) and particle precipitation in the premidnight sector on solar illumination at the ionosphere. The energy flux and average energy of precipitating electrons and ions are examined for downward R2 and upward Rl currents. Results are summarized as follows: (1) The Rl current density is larger in the dark hemisphere, whereas the dependence of R2 density on solar illumination is unclear. (2) For Rl currents the electron energy flux is larger and the average electron energy is higher in the dark hemisphere. (3) For R2 currents, a similar preference for the dark hemisphere is found for the electron energy flux, which, however, is significantly lower than for Rl currents. The average electron energy is similar between the two hemispheres. (4) For both Rl and R2 currents, ion precipitation is more intense and energetic in the dark hemisphere. (5) For a given field-aligned current density, whether Rl or R2 currents, both electron and ion precipitation is more intense and energetic in the dark hemisphere. The Pedersen conductivity is estimated from electron precipitation and solar illumination. The result suggests that in the dark hemisphere the absence of solar illumination is often overcompensated by more intense and energetic electron precipitation. The interhemispheric difference in electron acceleration may be interpreted in terms of plasma density in the acceleration region, which is known to be significantly lower in the dark hemisphere, and therefore electrons need to be more accelerated along the field line to carry imposed currents. Copyright 2009 by the American Geophysical Union.

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  • Merging Particle Filter and Its Characteristics Reviewed

    Vol.56 ( No.2 )   225 - 234   2008.12

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  • Bayesian learning of biological pathways on genomic data assimilation Reviewed

    Ryo Yoshida, Masao Nagasaki, Rui Yamaguchi, Seiya Imoto, Satoru Miyano, Tomoyuki Higuchi

    BIOINFORMATICS   24 ( 22 )   2592 - 2601   2008.11

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    Motivation: Mathematical modeling and simulation, based on biochemical rate equations, provide us a rigorous tool for unraveling complex mechanisms of biological pathways. To proceed to simulation experiments, it is an essential. first step to. find effective values of model parameters, which are difficult to measure from in vivo and in vitro experiments. Furthermore, once a set of hypothetical models has been created, any statistical criterion is needed to test the ability of the constructed models and to proceed to model revision.
    Results: The aim of our research is to present a new statistical technology towards data-driven construction of in silico biological pathways. The method starts with a knowledge-based modeling with hybrid functional Petri net. It then proceeds to the Bayesian learning of model parameters for which experimental data are available. This process exploits quantitative measurements of evolving biochemical reactions, e. g. gene expression data. Another important issue that we consider is statistical evaluation and comparison of the constructed hypothetical pathways. For this purpose, we have developed a new Bayesian information-theoretic measure that assesses the predictability and the biological robustness of in silico pathways.

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  • Rejoinder(<Special Section>Commemoration of the 75th Anniversary of the Japan Statistical society (III)) Reviewed

    Sato Tadahiko, Higuchi Tomoyuki

    Journal of the Japan Statistical Society Japanese issue   38 ( 1 )   31 - 38   2008.9

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  • An analysis of shopping trip behavior using dynamic individual model(<Special Section>Commemoration of the 75th Anniversary of the Japan Statistical society (III)) Reviewed

    Sato Tadahiko, Higuchi Tomoyuki

    Journal of the Japan Statistical Society Japanese issue   38 ( 1 )   1 - 19   2008.9

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    In the marketing field, activities such as One-to-One Marketing and Customer Relationship Management (CRM) have gotten a lot of attention for its effectiveness. The concept of those activities is based on the notion of consumer heterogeneity in the marketing. It is necessary to incorporate consumer heterogeneity and dynamic trait into a statistical model for evaluating the activities adequately. In this paper, we propose dynamic individual models for analyzing the shopping trip behavior individually. We formulate the model with framework of a general state space model. We realize an estimation of the model by using particle filter/fixed lag smoother. We show that the proposed model allow us to discriminate an individual's shopping trip behavior correctly using frequent shoppers data.

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  • A method for estimating the ring current structure and the electric potential distribution using energetic neutral atom data assimilation Reviewed

    S. Nakano, G. Ueno, Y. Ebihara, M. C. Fok, S. Ohtani, P. C. Brandt, D. G. Mitchell, K. Keika, T. Higuchi

    Journal of Geophysical Research: Space Physics   113 ( 5 )   5208   2008.5

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    We present a technique for estimating ring current ion distributions and electric potential in the inner magnetosphere by incorporating data from the High-Energy Neutral Atom (HENA) imager on the IMAGE satellite into a kinetic ring current model in the context of data assimilation. Data assimilation is an approach which adjusts a physicsbased model according to differences with observations. We perform the data assimilation using the particle filter (PF) which is applicable to high-dimensional systems and observations with relatively low computational cost. In the present technique, the magnetospheric electric potential distribution is represented by the sum of a Volland-Stern field and a deviation, and the deviation is improved in the assimilation process. The ring current ion distribution is then determined from the electric potential distribution. The method is tested by assimilating artificial data generated by another simulation. The results demonstrate that the ring current ion distribution is successfully reconstructed by the proposed algorithm and that the distorted structures of the electric potential distribution are also well reproduced. An example to illustrate how the present technique could be applied for assimilating a real IMAGE/HENA data set is also demonstrated. This technique provides a useful tool for investigating the global dynamic structure of ring current and electric potential. Copyright 2008 by the American Geophysical Union.

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  • Detection of Worn-out Banknote by Using Acoustic Signals : Time-varying Spectrum Classification by Divergence-based Kernel Machines Reviewed

    ISHIGAKI Tsukasa, HIGUCHI Tomoyuki

    44 ( 5 )   444 - 449   2008.5

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    DOI: 10.9746/ve.sicetr1965.44.444

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  • A method for estimating the ring current structure and the electric potential distribution using energetic neutral atom data assimilation Reviewed

    S. Nakano, G. Ueno, Y. Ebihara, M. -C. Fok, S. Ohtani, P. C. Brandt, D. G. Mitchell, K. Keika, T. Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   113 ( A5 )   A05208   2008.5

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    We present a technique for estimating ring current ion distributions and electric potential in the inner magnetosphere by incorporating data from the High-Energy Neutral Atom (HENA) imager on the IMAGE satellite into a kinetic ring current model in the context of data assimilation. Data assimilation is an approach which adjusts a physics-based model according to differences with observations. We perform the data assimilation using the particle filter (PF) which is applicable to high-dimensional systems and observations with relatively low computational cost. In the present technique, the magnetospheric electric potential distribution is represented by the sum of a Volland-Stern field and a deviation, and the deviation is improved in the assimilation process. The ring current ion distribution is then determined from the electric potential distribution. The method is tested by assimilating artificial data generated by another simulation. The results demonstrate that the ring current ion distribution is successfully reconstructed by the proposed algorithm and that the distorted structures of the electric potential distribution are also well reproduced. An example to illustrate how the present technique could be applied for assimilating a real IMAGE/HENA data set is also demonstrated. This technique provides a useful tool for investigating the global dynamic structure of ring current and electric potential.

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  • Geodetic inversion for space-time distribution of fault slip with time-varying smoothing regularization Reviewed

    Jun'ichi Fukuda, Shin'ichi Miyazaki, Tomoyuki Higuchi, Teruyuki Kato

    GEOPHYSICAL JOURNAL INTERNATIONAL   173 ( 1 )   25 - 48   2008.4

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    We have developed a new geodetic inversion method for space-time distribution of fault slip velocity with time-varying smoothing regularization in order to reconstruct accurate time histories of aseismic fault slip transients. We introduce a temporal smoothing regularization on slip and slip velocity through a Bayesian state space approach in which the strength of regularization (temporal smoothness of slip velocity) is controlled by a hyperparameter. The time-varying smoothing regularization is realized by treating the hyperparameter as a time-dependent stochastic variable and adopting a hierarchical Bayesian state space model, in which a prior distribution on the hyperparameter is introduced in addition to a conventional Bayesian state space model. We have tested this inversion method on two synthetic data sets generated by simulated aseismic slip transients. Results show that our method reproduces well both rapid changes of slip velocity and steady-state velocity without significant oversmoothing and undersmoothing, which has been hard to overcome by the conventional Bayesian approach with time-independent smoothing regularization. Application of this method to transient deformation in 2002 caused by a silent earthquake off the Boso peninsula, Japan, also shows similar advantages of this method over the conventional approach.

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  • Statistical inference of transcriptional module-based gene networks from time course gene expression profiles by using state space models Reviewed

    Osamu Hirose, Ryo Yoshida, Seiya Imoto, Rui Yamaguchi, Tomoyuki Higuchi, D. Stephen Charnock-Jones, Cristin Print, Satoru Miyano

    BIOINFORMATICS   24 ( 7 )   932 - 942   2008.4

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    Motivation: Statistical inference of gene networks by using time-course microarray gene expression profiles is an essential step towards understanding the temporal structure of gene regulatory mechanisms. Unfortunately, most of the current studies have been limited to analysing a small number of genes because the length of time-course gene expression profiles is fairly short. One promising approach to overcome such a limitation is to infer gene networks by exploring the potential transcriptional modules which are sets of genes sharing a common function or involved in the same pathway.
    Results: In this article, we present a novel approach based on the state space model to identify the transcriptional modules and module-based gene networks simultaneously. The state space model has the potential to infer large-scale gene networks, e.g. of order 10(3), from time-course gene expression profiles. Particularly, we succeeded in the identification of a cell cycle system by using the gene expression profiles of Saccharomyces cerevisiae in which the length of the time-course and number of genes were 24 and 4382, respectively. However, when analysing shorter time-course data, e.g. of length 10 or less, the parameter estimations of the state space model often fail due to overfitting. To extend the applicability of the state space model, we provide an approach to use the technical replicates of gene expression profiles, which are often measured in duplicate or triplicate. The use of technical replicates is important for achieving highly-efficient inferences of gene networks with short time-course data. The potential of the proposed method has been demonstrated through the time-course analysis of the gene expression profiles of human umbilical vein endothelial cells (HUVECs) undergoing growth factor deprivation-induced apoptosis.

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  • Parameter identification of a pressure regulator with a nonlinear structure using a particle filter based on the nonlinear state space model Reviewed

    Tsukasa Ishigaki, Tomoyuki Higuchi

    Proceedings of the 11th International Conference on Information Fusion, FUSION 2008   886 - 891   2008

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    Fusion of a simulation model and observation data has been investigated extensively for the purpose of data assimilation in geophysics. The inaccuracy of the parameters, initial conditions, or boundary conditions causes a discrepancy in the simulation results and the actual phenomenon. The present paper describes the parameter identification of a pressure regulator with a nonlinear structure by sequential Bayes estimation in the framework of data assimilation. A damping coefficient of feedback system in the pressure regulator that cannot be observed directly is estimated using a particle filter and a nonlinear state space model. The data assimilation concept is demonstrated using a pressure regulator as an engineering application.

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  • Dynamic spectrum classification by divergence-based kernel machines and its application to the detection of worn-out banknotes Reviewed

    Tsukasa Ishigaki, Tomoyuki Higuchi

    2008 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-12   1873 - +   2008

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    In the kernel method, the appropriate selection or design of the kernel function is important for the construction of a high-performance classifier. The present paper describes a dynamic spectrum classification method using kernel classifiers with the divergence-based kernel and its application to the detection of worn-out banknotes. We introduce the divergence-based kernel that was proposed as a measure between two probability distributions into the dynamic spectrum classification. The present method is applied to the detection of worn-out banknotes by using acoustic signals for the facilitation of identifying counterfeit banknotes. As a result, the classification performance using the divergence-based kernel is shown to have better performance than those using common kernels such as the Gaussian kernel or the polynomial kernel.

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  • PREDICTING DIFFERENCES IN GENE REGULATORY SYSTEMS BY STATE SPACE MODELS Reviewed

    Rui Yamaguchi, Seiya Imoto, Mai Yamauchi, Masao Nagasaki, Ryo Yoshida, Teppei Shimamura, Yosuke Hatanaka, Kazuko Ueno, Tomoyuki Higuchi, Noriko Gotoh, Satoru Miyano

    GENOME INFORMATICS 2008, VOL 21   21   101 - +   2008

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    We propose a statistical strategy to predict differentially regulated genes of case and control samples from time-course gene expression data by leveraging unpredictability of the expression patterns from the underlying regulatory system inferred by a state space model. The proposed method can screen out genes that show different patterns but generated by the same regulations in both samples, since these patterns can be predicted by the same model. Our strategy consists of three steps. Firstly, a gene regulatory system is inferred from the control data by a state space model. Then the obtained model for the underlying regulatory system of the control sample is used to predict the case data. Finally, by assessing the significance of the difference between case and predicted-case time-course data of each gene, we are able to detect the unpredictable genes that are the candidate as the key differences between the regulatory systems of case and control cells. We illustrate the whole process of the strategy by an actual example, where human small airway epithelial cell gene regulatory systems were generated from novel time courses of gene expressions following treatment with (case)/without(control) the drug gefitinib, an inhibitor for the epidermal growth factor receptor tyrosine kinase. Finally, in gefitinib response data we succeeded in finding unpredictable genes that are candidates of the specific targets of gefitinib. We also discussed differences in regulatory systems for the unpredictable genes. The proposed method would be a promising tool for identifying biomarkers and drug target genes.

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  • PREDICTING DIFFERENCES IN GENE REGULATORY SYSTEMS BY STATE SPACE MODELS Reviewed

    Rui Yamaguchi, Seiya Imoto, Mai Yamauchi, Masao Nagasaki, Ryo Yoshida, Teppei Shimamura, Yosuke Hatanaka, Kazuko Ueno, Tomoyuki Higuchi, Noriko Gotoh, Satoru Miyano

    GENOME INFORMATICS 2008, VOL 21   21   101 - +   2008

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    We propose a statistical strategy to predict differentially regulated genes of case and control samples from time-course gene expression data by leveraging unpredictability of the expression patterns from the underlying regulatory system inferred by a state space model. The proposed method can screen out genes that show different patterns but generated by the same regulations in both samples, since these patterns can be predicted by the same model. Our strategy consists of three steps. Firstly, a gene regulatory system is inferred from the control data by a state space model. Then the obtained model for the underlying regulatory system of the control sample is used to predict the case data. Finally, by assessing the significance of the difference between case and predicted-case time-course data of each gene, we are able to detect the unpredictable genes that are the candidate as the key differences between the regulatory systems of case and control cells. We illustrate the whole process of the strategy by an actual example, where human small airway epithelial cell gene regulatory systems were generated from novel time courses of gene expressions following treatment with (case)/without(control) the drug gefitinib, an inhibitor for the epidermal growth factor receptor tyrosine kinase. Finally, in gefitinib response data we succeeded in finding unpredictable genes that are candidates of the specific targets of gefitinib. We also discussed differences in regulatory systems for the unpredictable genes. The proposed method would be a promising tool for identifying biomarkers and drug target genes.

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  • ハリウッド映画に見る近未来の情報技術:パーソナライゼーション技術

    樋口 知之

    日本知能情報ファジー学会   Vol.20 ( No.2 )   1   2008

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  • Analyzing time course gene expression data with biological and technical replicates to estimate gene networks by state space models Reviewed

    Osamu Hirose, Ryo Yoshida, Rui Yamaguchi, Seiya Imoto, Tomoyuki Higuchi, Satoru Miyano

    Proceedings - 2nd Asia International Conference on Modelling and Simulation, AMS 2008   940 - 946   2008

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    In order to estimate accurate gene networks from time course gene expression data, replicated time course data are useful. However, existing methods do not clearly distinguish between biological and technical replicates, while these two kinds of replicates have different features. In this paper, we propose a statistical model based on state space models to use biologically and technically replicated time course data and show an algorithm to estimate a gene network that is a graphical representation of gene-gene regulation. To our knowledge, for estimating gene networks, the proposed model is the first model that can simultaneously use two types of replicated time course data. We show the effectiveness of the proposed method through the analysis of the microarray human T-cell data. © 2008 IEEE.

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  • Deterioration diagnosis of pressure regulator for high pressure gas by spectrum classification with the Kullback-Leibler Kernel Reviewed

    Ishigaki T, Higuchi T, Watanabe K

    The Journal of the Institute of Electronics, Information and Communication Engineers   Vol.J90-D ( No.10 )   2787 - 2797   2007.10

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  • Particle precipitation characteristics in the dayside four-sheet field-aligned current structure Reviewed

    Genta Ueno, Tomoyuki Higuchi, Shin-Ichi Ohtani, Patrick T. Newell

    Journal of Geophysical Research: Space Physics   112 ( 6 )   2007.6

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    We study the statistical characteristics of four-sheet structures of large scale field-aligned currents (FACs) with an emphasis on particle precipitation collocated with each FAC sheet observed in dayside using magnetic field and particle precipitation data from the Defense Meteorological Satellite Program (DMSP). A total of 3247 four-sheet events were identified by applying an automatic procedure to the magnetic field data. The occurrence frequency of the events was less than 10% in each magnetic local time (MLT) sector for both hemispheres. The selected events were classified into two groups (type W and type M) with respect to the polarity of FACs. The polarity of the most equatorward type W (type M) FAC sheet is upward (downward). Type W (type M) events are observed predominantly in the morning (evening) sector and display a clear interplanetary magnetic field (IMF) BY dependence. Type W (type M) events appear for negative (positive) IMF BY in the Northern Hemisphere with the opposite dependence in the Southern Hemisphere. For each FAC sheet for type W events, we examined the occurrence of different precipitation regions identified with another automatic procedure. The most equatorward FAC sheet is collocated predominantly with central plasma sheet precipitation except for the prenoon sector, where boundary plasma sheet (BPS) precipitation has the highest occurrence. For the second and the third equatorward sheets, boundary layer-like precipitation, BPS near dawn and low-latitude boundary layer near noon, is dominant. In the most poleward sheet, mantle precipitation was observed frequently near noon, while BPS precipitation was dominant at earlier MLTs. These results, especially precipitation characteristics near noon, are consistent with our interpretation of the four-sheet structures, which is based on IMF BY dependence of convection patterns consisting of lobe, merging, and viscous cells. Copyright 2007 by the American Geophysical Union.

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  • Particle precipitation characteristics in the dayside four-sheet field-aligned current structure Reviewed

    Genta Ueno, Tomoyuki Higuchi, Shin-ichi Ohtani, Patrick T. Newell

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   112 ( A6 )   A06242   2007.6

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    We study the statistical characteristics of four-sheet structures of large scale field-aligned currents (FACs) with an emphasis on particle precipitation collocated with each FAC sheet observed in dayside using magnetic field and particle precipitation data from the Defense Meteorological Satellite Program (DMSP). A total of 3247 four-sheet events were identified by applying an automatic procedure to the magnetic field data. The occurrence frequency of the events was less than 10% in each magnetic local time (MLT) sector for both hemispheres. The selected events were classified into two groups (type Wand type M) with respect to the polarity of FACs. The polarity of the most equatorward type W (type M) FAC sheet is upward (downward). Type W (type M) events are observed predominantly in the morning (evening) sector and display a clear interplanetary magnetic field (IMF) B-Y dependence. Type W (type M) events appear for negative (positive) IMF B-Y in the Northern Hemisphere with the opposite dependence in the Southern Hemisphere. For each FAC sheet for type W events, we examined the occurrence of different precipitation regions identified with another automatic procedure. The most equatorward FAC sheet is collocated predominantly with central plasma sheet precipitation except for the prenoon sector, where boundary plasma sheet (BPS) precipitation has the highest occurrence. For the second and the third equatorward sheets, boundary layer-like precipitation, BPS near dawn and low-latitude boundary layer near noon, is dominant. In the most poleward sheet, mantle precipitation was observed frequently near noon, while BPS precipitation was dominant at earlier MLTs. These results, especially precipitation characteristics near noon, are consistent with our interpretation of the four-sheet structures, which is based on IMF B-Y dependence of convection patterns consisting of lobe, merging, and viscous cells.

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  • Information fusion-based multiobjective security system with a multiple-input/single-output sensor Reviewed

    Tsukasa Ishigaki, Tomoyuki Higuchi, Kajiro Watanabe

    IEEE SENSORS JOURNAL   7 ( 5-6 )   734 - 742   2007.5

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    In the framework of sensor fusion, multiple sensors corresponding to the number of physical variables that must be measured are used. In this paper, we propose a novel sensing approach that simultaneously deals with heterogeneous physical variables with a sensor. It is fundamentally different from sensor fusion. The proposed approach takes into consideration the fact that any sensor that detects a certain physical variable is influenced to a degree by other physical variables, which are designated as noise. The objective in conventional sensor design has been the minimization of noise. In contrast, the proposed approach takes advantage of sensors that are easily influenced by many physical variables and makes full use of the multisensing characteristics of these sensors. The system designed using this concept has advantages in terms of cost performance and system simplification compared to existing approaches. This concept can be realized by developing a novel multiple-input/single-output sensor that can detect various variables, including pressure, acceleration, temperature and incandescent light emission, by a single device. We apply the sensor to monitor the symptoms of fire, earthquakes, and break-ins for the purpose of home security. The proposed security system is realized through statistical signal processing and machine learning techniques.

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  • Finding module-based gene networks with state-space models Reviewed

    Rui Yamaguchi, Ryo Yoshida, Seiya Imoto, Tomoyuki Higuchi, Satoru Miyano

    IEEE SIGNAL PROCESSING MAGAZINE   24 ( 1 )   37 - 46   2007.1

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  • Merging particle filter for sequential data assimilation Reviewed

    S. Nakano, G. Ueno, T. Higuchi

    NONLINEAR PROCESSES IN GEOPHYSICS   14 ( 4 )   395 - 408   2007

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    A new filtering technique for sequential data assimilation, the merging particle filter (MPF), is proposed. The MPF is devised to avoid the degeneration problem, which is inevitable in the particle filter (PF), without prohibitive computational cost. In addition, it is applicable to cases in which a nonlinear relationship exists between a state and observed data where the application of the ensemble Kalman filter (EnKF) is not effectual. In the MPF, the filtering procedure is performed based on sampling of a forecast ensemble as in the PF. However, unlike the PF, each member of a filtered ensemble is generated by merging multiple samples from the forecast ensemble such that the mean and covariance of the filtered distribution are approximately preserved. This merging of multiple samples allows the degeneration problem to be avoided. In the present study, the newly proposed MPF technique is introduced, and its performance is demonstrated experimentally.

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  • A knowledge discovery from POS data using state space models: An analysis of change in price elasticities by new product's entry to market Reviewed

    Tadahiko Sato, Tomoyuki Higuchi

    Transactions of the Japanese Society for Artificial Intelligence   22 ( 2 )   200 - 208   2007

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    The number of competing-brands changes by new product's entry. The new product introduction is endemic among consumer packaged goods firm and is an integral component of their marketing strategy. As a new product's entry affects markets, there is a pressing need to develop market response model that can adapt to such changes. In this paper, we develop a dynamic model that capture the underlying evolution of the buying behavior associated with the new product. This extends an application of a dynamic linear model, which is used by a number of time series analyses, by allowing the observed dimension to change at some point in time. Our model copes with a problem that dynamic environments entail: changes in parameter over time and changes in the observed dimension. We formulate the model with framework of a state space model. We realize an estimation of the model using modified Kalman filter/fixed interval smoother. We find that new product's entry (1) decreases brand differentiation for existing brands, as indicated by decreasing difference between cross-price elasticities
    (2) decreases commodity power for existing brands, as indicated by decreasing trend
    and (3) decreases the effect of discount for existing brands, as indicated by a decrease in the magnitude of own-brand price elasticities. The proposed framework is directly applicable to other fields in which the observed dimension might be change, such as economic, bioinformatics, and so forth.

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  • Spectrum classification for early fault diagnosis of the LP gas pressure regulator based on the Kullback-Leibler kernel Reviewed

    Tsukasa Ishigaki, Tomoyuki Higuchi, Kajiro Watanabe

    Proceedings of the 2006 16th IEEE Signal Processing Society Workshop on Machine Learning for Signal Processing, MLSP 2006   453 - 458   2007

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    The present paper describes a frequency spectrum classification method for fault diagnosis of the LP gas pressure regulator using Support Vector Machines. Conventional diagnosis methods are not efficient because of problems such as significant noise and nonlinearity of the detection mechanism. In order to solve these problems, a machine learning method with the Kullback-Leibler (KL) kernel based on the KL divergence is introduced into spectrum classification. We use the normalized frequency spectrum directly as input with the KL kernel. The proposed method demonstrates a higher accuracy than popular kernels, such as polynomial or Gaussian kernels, or the conventional fault diagnosis method and Gaussian Mixture Model with the KL kernel for the examined problem. The high classification performance is achieved by using an inexpensive sensor system and the machine learning method. This method is widely applicable to other spectrum classification applications without limitation on the generality if the spectrums are normalized.

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  • Application of the Ensemble Kalman Filter and Smoother to a Coupled Atmosphere-ocean Model Reviewed

    Genta Ueno, Tomoyuki Higuchi, Takashi Kagimoto, Naoki Hirose

    SOLA   3   5 - 8   2007

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    We report an application of the ensemble Kalman filter (EnKF) and smoother (EnKS) to an intermediate coupled atmosphere-ocean model of Zebiak and Cane, into which the sea surface height (SSH) anomaly observations by TOPEX/POSEIDON (T/P) altimetry are assimilated. Smoothed estimates of the 54,403 dimensional state are obtained from 1,981 observational points with 2,048 ensemble members. While assimilated data are SSH anomalies alone, the estimated sea surface temperature (SST) anomalies reproduce primary temporal characteristics of the actual SST. The smoothed estimate of the zonal wind anomalies is also consistent with the observation except for the westerly anomalies in the western Pacific.

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  • Clustering samples characterized by time course gene expression profiles using the mixture of state space models Reviewed

    Osamu Hirose, Ryo Yoshida, Rui Yamaguchi, Seiya Imoto, Tomoyuki Higuchi, Satoru Miyano

    GENOME INFORMATICS 2007, VOL 18   18   258 - +   2007

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    We propose a novel method to classify samples where each sample is characterized by a time course gene expression profile. By exploiting the mixture of state space model, the proposed method addresses the following tasks: (1) clustering samples according to temporal patterns of gene expressions, (2) automatic detection of genes that discriminate identified clusters, (3) estimation of a restricted autoregressive coefficient for each cluster. We demonstrate the proposed method along with the cluster analysis of 53 multiple sclerosis patients under recombinant interferon beta therapy with the longitudinal time course expression profiles.

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  • POSデータの時系列モデリングによる知識発見 : 新製品投入の消費者価格反応変化に及ぼす影響の解析 Reviewed

    佐藤忠彦, 樋口知之

    人工知能学会論文誌   22 ( 2 )   200 - 208   2007

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    The number of competing-brands changes by new products entry. The new product introduction is endemic among consumer packaged goods firm and is an integral component of their marketing strategy. As a new products entry affects markets, there is a pressing need to develop market response model that can adapt to such changes. In this paper, we develop a dynamic model that capture the underlying evolution of the buying behavior associated with the new product. This extends an application of a dynamic linear model, which is used by a number of time series analyses, by allowing the observed dime...

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  • Graph Mining and Its Application to Statistical Modeling

    54 ( 2 )   315 - 331   2006.12

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  • Automatic Online Detection and Classification of Occurring Disaster with a Multivariable Detecting Sensor for Home Security System Reviewed

    ISHIGAKI Tsukasa, HIGUCHI Tomoyuki, WATANABE Kajiro

    The IEICE transactions on information and systems   89 ( 11 )   2404 - 2412   2006.11

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  • ArrayCluster: an analytic tool for clustering, data visualization and module finder on gene expression profiles Reviewed

    Ryo Yoshida, Tomoyuki Higuchi, Seiya Imoto, Satoru Miyano

    BIOINFORMATICS   22 ( 12 )   1538 - 1539   2006.6

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    One of the significant challenges in gene expression analysis is to find unknown subtypes of several diseases at the molecular levels. This task can be addressed by grouping gene expression patterns of the collected samples on the basis of a large number of genes. Application of commonly used clustering methods to such a dataset however are likely to fail owing to over-learning, because the number of samples to be grouped is much smaller than the data dimension which is equal to the number of genes involved in the dataset. To overcome such difficulty, we developed a novel model-based clustering method, referred to as the mixed factors analysis. The ArrayCluster is a freely available software to perform the mixed factors analysis. It provides us some analytic tools for clustering DNA microarray experiments, data visualization and an automatic detector for module transcriptional of genes that are relevant to the calibrated molecular subtypes and so on.

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  • Adjustment of sampling locations in rail-geometry datasets: Using dynamic programming and nonlinear filtering Reviewed

    Masako Kamiyama, Tomoyuki Higuchi

    Systems and Computers in Japan   37 ( 1 )   61 - 70   2006.1

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    A track inspection car, which measures the shape of railway tracks (hereafter, rail geometry) while it is running on rails, discretizes the measurement results at nearly fixed spatial intervals. However, the distance between the discretized locations (spatial sampling intervals) may shorten or lengthen locally due to slipping or sliding of the car wheel, and this prevents the sampling locations from aligning with those of a dataset obtained with another measuring run. The authors developed an algorithm for approximately aligning the sampling locations of the measurement datasets obtained with different runs. First, they considered this problem as the selection of the series of data corresponding to each supervised data from a training dataset, which was constructed by interpolation in order to minimize the evaluation function of a number sequence representing data points. Next, they used the maximum likelihood method to identify the unknown parameters contained in the evaluation function. This problem uses two features of the evaluation function. The first is that the evaluation function is minimized by dynamic programming, and the obtained optimum sequence is equivalent to a maximum a posteriori (MAP) estimate in the Bayesian framework. The second is that by converting the evaluation function to a general state space representation, the log likelihood of the model that includes the parameters is obtained by a nonlinear filtering method. Also, to simplify the search for the identification, they devised a parameter search procedure for the parameters in the autoregressive (AR) model. © 2005 Wiley Periodicals, Inc.

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  • Error tolerant model for incorporating biological knowledge with expression data in estimating gene networks Reviewed

    Seiya Imoto, Tomoyuki Higuchi, Takao Goto, Satoru Miyano

    Statistical Methodology   3 ( 1 )   1 - 16   2006.1

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    We propose a novel statistical method for estimating gene networks based on microarray gene expression data together with information from biological knowledge databases. Although a large amount of gene regulation information has already been stored in some biological databases, there are still errors and missing facts due to experimental problems and human errors. Therefore, we cannot blindly use them for understanding gene regulation and a robust procedure with a statistical model for using such database information is required. By using gene expression data, we provide a probabilistic framework of a joint learning model for repairing database information and for estimating a gene network based on dynamic Bayesian networks, simultaneously. To show the effectiveness of the proposed method, we analyze Saccharomyces cerevisiae cell-cycle gene expression data together with KEGG information. © 2005 Elsevier B.V. All rights reserved.

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  • Application of the ensemble Kalman filter to atmosphere-ocean coupled model Reviewed

    G. Ueno, T. Higuchi, T. Kagimoto, N. Hirose

    NSSPW: NONLINEAR STATISTICAL SIGNAL PROCESSING WORKSHOP   125 - +   2006

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    We report the first application of the ensemble Kalman filter (EnKF) to an intermediate coupled atmosphere-ocean model by [1], into which the sea surface height (SSH) anomaly observations by TOPEX/POSEIDON (T/P) altimetry are assimilated. Smoothed estimates of the 54,403 dimensional state are obtained from 1981 observational points with 2048 ensemble members. While data assimilated are SSH anomalies alone, an ensemble experiment of 2002/03 El Ni (n) over tildeo event based on the EnKF can predict consistent Ni (n) over tildeo 3 sea surface temperature (SST) anomalies about 5 months in advance.

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  • State-space approach with the maximum likelihood principle to identify the system generating time-course gene expression data of yeast Reviewed

    Rui Yamaguchi, Tomoyuki Higuchi

    INTERNATIONAL JOURNAL OF DATA MINING AND BIOINFORMATICS   1 ( 1 )   77 - 87   2006

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    We use linear Gaussian state-space models to analyse time-course gene expression data of yeast. They are modelled to be generated from hidden state variables in a system. To identify the system, we estimate parameters of the model by EM algorithm and determine the dimension of the state variable by BIC.

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  • Sequential data assimilation: Information fusion of a numerical simulation and large scale observation data Reviewed

    Kazuyuki Nakamura, Tomoyuki Higuchi, Naoki Hirose

    JOURNAL OF UNIVERSAL COMPUTER SCIENCE   12 ( 6 )   608 - 626   2006

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    Data assimilation is a method of combining an imperfect simulation model and a number of incomplete observation data. Sequential data assimilation is a data assimilation in which simulation variables are corrected at every time step of observation. The ensemble Kalman filter is developed for a sequential data assimilation and frequently used in geophysics. On the other hand, the particle filter developed and used in statistics is similar in view of ensemble-based method, but it has different properties. In this paper, these two ensemble based filters are compared and characterized through matrix representation. An application of sequential data assimilation to tsunami simulation model with a numerical experiment is also shown. The particle filter is employed for this application. An erroneous bottom topography is corrected in the numerical experiment, which demonstrates that the particle filter is useful tool as the sequential data assimilation method.

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  • A multi-variable detecting sensor and its application Reviewed

    Kenji Koyama, Kajiro Watanabe, Kazuyuki Kobayashi, Tosuke Kurihara, Tsukasa Ishigaki, Tomoyuki Higuchi

    2006 SICE-ICASE INTERNATIONAL JOINT CONFERENCE, VOLS 1-13   1004 - +   2006

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    Any sensor to detect a certain physical variable is influenced to some degree by other physical variables designated as "noise". The objective in conventional sensor design is to minimize such noise. In this study, conversely we welcome sensing devices that are easily influenced by many physical variables and make full use of their multi-sensing characteristic. We consider such devices as multiple-inputs and single-output sensors. The output signal derived from multiple input signals must be dissociated. The input signals resulting from physical realities have inherent characteristics and can be mathematically modeled. Application of a Kalman filter realized by such models can provide estimates of state variables of all input models, and thus the input signals can be dissociated. As an example, a novel sensor based on a microphone is presented. It can detect various variables such as pressure and acceleration in the frequency range of 0.1 Hz to 10 kHz, temperature, and even light emission. We use the sensor to monitor the symptoms of fire, earthquake and break-in by intruders from within a house.

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  • Online detection and classification of disasters by a multiple-input/single-output sensor for a home security system Reviewed

    Tsukasa Ishigaki, Tomoyuki Higuchi, Kajiro Watanabe

    2006 IEEE INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORK PROCEEDINGS, VOLS 1-10   3136 - +   2006

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    Conventional sensors have been designed to minimize noise effects. Any sensor that is designed to detect a certain physical variable is influenced to a certain degree by other physical variables. This suggests that any sensor is potentially capable of detecting multiple physical variables. In the present study, we consider sensing devices that are easily influenced by several physical variables and make full use of their multi-sensing characteristics through statistical signal processing and machine learning techniques with a wide variety of prior information. The proposed sensor design approach is completely different from the conventional approach with respect to system design and has advantages in terms of cost and system simplification compared to existing approaches. This new idea can be realized by developing a novel multiple-input/single-output sensor that can detect various variables such as pressure, acceleration, temperature and light emission by a single device. The sensor is applied to monitor the symptoms of fire, earthquake and break-in for the purpose of home security. The proposed security system consists of the following three steps: (1) Detection of disaster by a probabilistic outlier detection procedure using an auto-regressive model, (2) Disaster feature extraction by Kaiman filter on a state space model, and (3) Disaster classification by multiclass support vector machine.

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  • From closed tree mining towards closed DAG mining Reviewed

    Alexandre TermierYoshinori TamadaSeiya ImotoTakashi WashioTomoyuki Higuchi

    Proc. DMSS2006 : The Int. Workshop on Data-Mining and Statistical Science   1 - 7   2006

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  • Genomic data assimilation for estimating hybrid functional Petri net from time-course gene expression data. Reviewed

    Nagasaki, M., Yamaguchi, R., Yoshida, R., Imoto, S., Doi, A., Tamada, Y., Matsuno, H., Miyano, S., Higuchi, T.

    Genome informatics. International Conference on Genome Informatics   17 ( 1 )   46 - 61   2006

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  • Modeling and estimation of dynamic EGFR pathway by data assimilation approach using time series proteomic data. Reviewed

    Tasaki S, Nagasaki M, Oyama M, Hata H, Ueno K, Yoshida R, Higuchi T, Sugano S, Miyano S

    Genome informatics. International Conference on Genome Informatics   17 ( 2 )   226 - 238   2006

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    Cell Illustrator is a model building tool based on the Hybrid Functional Petri net with extension (HFPNe). By using Cell Illustrator, we have succeeded in modeling biological pathways, e.g., metabolic pathways, gene regulatory networks, microRNA regulatory networks, cell signaling networks, and cell-cell interactions. The recent development of tandem mass spectrometry coupled with liquid chromatography (LC/MS/MS) technology has enabled researchers to quantify the dynamic profile of a wide range of proteins within the cell. The proteomic data obtained by using LC/MS/MS has been considerably useful for introducing dynamics to the HFPNe model. Here, we report the first introduction of the time-series proteomic data to our HFPNe model. We constructed an epidermal growth factor receptor signal transduction pathway model (EFGR model) by using the biological data available in the literature. Then, the kinetic parameters were determined in the data assimilation (DA) framework with some manual tuning so as to fit the proteomic data published by Blagoev et al. (Nat. Biotechnol., 22:1139-1145, 2004). This in silico model was further refined by adding or removing some regulation loops using biological background knowledge. The DA framework was used to select the most plausible model from among the refined models. By using the proteomic data, we semi-automatically constructed a well-tuned EGFR HFPNe model by using the Cell Illustrator coupled with the DA framework.

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  • Statistical Inference using Stochastic Switching Models for the Discrimination of Unobserved Non-Price Promotion Reviewed

    Sato Tadahiko, Higuchi Tomoyuki, Kitagawa Genshiro

    Transactions of the Japan Society for Industrial and Applied Mathematics   15 ( 4 )   537 - 570   2005.12

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    It is known that an execution of price and/or a non-price promotion has a strong influence on the sales of a brand sold in a supermarket. Usually, we can easily obtain information on a price promotion from a POS data. On the other hand, unless investigator collects information on an execution of non-price promotion in every retail store, we can not obtain such information. In this paper, we consider a problem to identify whether or not non-price promotion is conducted. We treat a non-price promotion execution/non-execution as a state variable. An unknown stationary probability matrix is assumed to describe the probability of a transition between states. Each state is characterized by a different stationary time series model with unknown parameters. An objective of the analysis is to identify the model and to assign a probability model for each state at each time instant. Finally, we give a high precision estimator of a past non-price promotion based on the proposal model.

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  • Particle Filter Invited

    HIGUCHI Tomoyuki

    The Journal of the Institute of Electronics, Information and Communication Engineers   88 ( 12 )   989 - 994   2005.12

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  • Missing Region Modeling and the Multivariate Normal Mixture Model Reviewed

    NAKAMURA Nagatomo, UENO Genta, HIGUCHI Tomoyuki, KONISHI Sadanori

    Ouyou toukeigaku   34 ( 2 )   57 - 73   2005.12

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    A dataset that contains missing regions is assumed to arise from two or more populations. In order to decompose the data into meaningful component distributions, a normal mixture model can be applied. A problem with this approach is that the estimated parameters are biased by fitting the standard normal mixture model. To correct the bias, a log-likelihood function for missing region probabilities is constructed, and the maximum likelihood estimators of the parameters - i.e. mix-ing proportions, mean vectors, and variance-covariance matrixes - are derived in the context of the EM algorithm. The performance of the model is verified by numerical experiments, and the model is applied to plasma velocity data.

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  • Comparison of large-scale field-aligned currents under sunlit and dark ionospheric conditions Reviewed

    S Ohtani, G Ueno, T Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   110 ( A9 )   2005.9

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    [1] The present study statistically compares large-scale field-aligned currents (FACs) under sunlit and dark ionospheric conditions. A total of similar to 74,000 auroral oval crossings are selected from magnetic field measurements from the DMSP F7 and F12 to F15 satellites. For the dayside FAC it is reconfirmed that both current intensity and density are statistically larger in the illuminated events than in the unilluminated events. As for the nightside FAC, in contrast, a few important features become clear for the first time, which can be summarized as follows: ( 1) At 20 &lt;= MLT &lt; 02 both R1 and R2 intensities tend to be larger when the ionosphere is dark than when it is sunlit. ( 2) Although dependence on the ionospheric condition is less clear for the FAC density, a systematic preference of the occurrence of strong FACs for the dark ionosphere can be found for both R1 and R2 currents in the dusk-to-premidnight ( 16 &lt;= MLT &lt; 22) sector and for the R1 current in the postmidnight sector ( 00 &lt;= MLT &lt; 02). ( 3) For both FAC intensity and density the difference between the illuminated and unilluminated events tends to increase with increasing geomagnetic activity as measured by the IMF B-Z component. Result 1 can be partially explained in terms of the interhemispheric asymmetry of the magnetospheric configuration, which, however, should not affect the FAC density. Therefore result 2 strongly suggests that the solar-induced conductivity controls the M-I coupling in a different way in certain nightside MLT sectors than in dayside sectors.

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  • Annual and semiannual variations of the location and intensity of large-scale field-aligned currents Reviewed

    S Ohtani, G Ueno, T Higuchi, H Kawano

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   110 ( A1 )   2005.1

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    [ 1] The present study examines seasonal variations of large- scale field- aligned current ( FAC) systems in terms of the dipole tilt and clock angles. Magnetic field measurements from the DMSP F7 and F12- F15 satellites are used. This data set consists of a total of similar to 185,000 auroral oval crossings, out of which similar to 121,000 crossings were selected for the present analysis. Focus is placed on the latitude at the demarcation between the region 2 ( R2) and region 1 ( R1) currents and the intensities of these currents. It is found that the dayside FAC moves poleward and equatorward in the summer and winter hemispheres, respectively, and the nightside FAC has the opposite seasonal dependence. In the midday sector the peak- to- peak variation of the FAC latitude over the entire range of the dipole tilt is similar to5degrees, whereas it is similar to4degrees around midnight. In the flank sectors the average FAC latitude is higher around the solstices than around the equinoxes irrespective of hemisphere. The corresponding dependence on the dipole clock angle can actually be found for almost all local time sectors, although the peak- to- peak variation of the expected semiannual variation, 2 degrees around noon and &lt; 1 &DEG; in other local time sectors, is smaller than that of the annual variation except for the flank sectors. A comparison with a model magnetic field strongly suggests that the dipole tilt effect on the magnetospheric configuration is the primary cause of the annual variation, whereas the semiannual variation is inferred to reflect the fact that geomagnetic activity tends to be higher around the equinoxes. The average dayside FAC intensity is larger in the summer hemisphere than in the winter hemisphere, which can be explained in terms of the seasonal variation of the ionospheric conductivity. The dayside R1 current intensity depends more strongly on the dipole tilt than the dayside R2 current intensity, and it changes by a factor of 2 - 3 over the entire range of the dipole tilt angle. In contrast, the annual variation of the nightside FAC intensity is more complicated, and the nightside R2 current seems to be more intense in the winter hemisphere than in the summer hemisphere. The dependence of the FAC intensity on the dipole clock angle is less significant especially for the R1 system. Nevertheless, the result suggests that the FAC tends to be more intense around the equinoxes, which is consistent with the semiannual variation of geomagnetic activity.

    DOI: 10.1029/2004JA010634

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  • データ同化:その概念と計算アルゴリズム Reviewed

    中村和幸, 上野玄太, 樋口知之

    統計数理   53 ( 2 )   211 - 229   2005

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  • Comparison of large-scale field-aligned currents under sunlit and dark ionospheric conditions Reviewed

    S. Ohtani, G. Ueno, T. Higuchi

    Journal of Geophysical Research: Space Physics   110 ( 9 )   2005

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    The present study statistically compares large-scale field-aligned currents (FACs) under sunlit and dark ionospheric conditions. A total of ∼74,000 auroral oval crossings are selected from magnetic field measurements from the DMSP F7 and F12 to F15 satellites. For the dayside FAC it is reconfirmed that both current intensity and density are statistically larger in the illuminated events than in the unilluminated events. As for the nightside FAC, in contrast, a few important features become clear for the first time, which can be summarized as follows: (1) At 20 ≤ MLT &lt
    02 both R1 and R2 intensities tend to be larger when the ionosphere is dark than when it is sunlit. (2) Although dependence on the ionospheric condition is less clear for the FAC density, a systematic preference of the occurrence of strong FACs for the dark ionosphere can be found for both R1 and R2 currents in the dusk-to-premidnight (16 ≤ MLT &lt
    22) sector and for the R1 current in the postmidnight sector (00 ≤ MLT &lt
    02). (3) For both FAC intensity and density the difference between the illuminated and unilluminated events tends to increase with increasing geomagnetic activity as measured by the IMF BZ component. Result I can be partially explained in terms of the interhemispheric asymmetry of the magnetospheric configuration, which, however, should not affect the FAC density. Therefore result 2 strongly suggests that the solar-induced conductivity controls the M-I coupling in a different way in certain nightside MLT sectors than in dayside sectors. Copyright 2005 by the American Geophysical Union.

    DOI: 10.1029/2005JA011057

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  • Estimating time-dependent gene networks from time series microarray data by dynamic linear models with Markov switching Reviewed

    R Yoshida, S Imoto, T Higuchi

    2005 IEEE Computational Systems Bioinformatics Conference, Proceedings   289 - 298   2005

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    In gene network, estimation from time series microarray data, dynamic models such as differential equations and dynamic Bayesian networks assume that the network structure is stable through all time points, while the real network might changes its structure depending on time, affection of some shocks and so on. If the true network structure underlying the data changes at certain points, the fitting of the usual dynamic linear models fails to estimate the structure of gene network and we cannot obtain efficient information from data. To solve this problem, we propose a dynamic linear model with Markov switching for estimating time-dependent network-struture from time series gene expression data. Using our proposed method, the network structure between genes and its change points are autoniatically estimated We demonstrate the effectiveness of the proposed method through the analysis of Saccharomyces cerevisiae cell cycle time series data.

    DOI: 10.1109/CSB.2005.32

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  • Estimating time-dependent gene networks from time series microarray data by dynamic linear models with Markov switching Reviewed

    R Yoshida, S Imoto, T Higuchi

    2005 IEEE Computational Systems Bioinformatics Conference, Proceedings   289 - 298   2005

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    In gene network, estimation from time series microarray data, dynamic models such as differential equations and dynamic Bayesian networks assume that the network structure is stable through all time points, while the real network might changes its structure depending on time, affection of some shocks and so on. If the true network structure underlying the data changes at certain points, the fitting of the usual dynamic linear models fails to estimate the structure of gene network and we cannot obtain efficient information from data. To solve this problem, we propose a dynamic linear model with Markov switching for estimating time-dependent network-struture from time series gene expression data. Using our proposed method, the network structure between genes and its change points are autoniatically estimated We demonstrate the effectiveness of the proposed method through the analysis of Saccharomyces cerevisiae cell cycle time series data.

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  • Annual and semiannual variations of the location and intensity of large-scale field-aligned currents Reviewed

    S. Ohtani, G. Ueno, T. Higuchi, H. Kawano

    Journal of Geophysical Research: Space Physics   110 ( 1 )   2005

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    The present study examines seasonal variations of large-scale field-aligned current(FAC) Systems in terms of the dipole tilt and clock angles. Magnetic field measurements from the DMSP F7 and F12-F15 satellites are used. This data set consists of a total of ∼185,000 auroral oval crossings, out of which ∼121,000 crossings were selected for the present analysis. Focus is placed on the latitude at the demarcation between the region 2 (R2) and region 1 (R1) currents and the intensities of these currents. It is found that the dayside FAC moves poleward and equatorward in the summer and winter hemispheres, respectively, and the nightside FAC has the opposite seasonal dependence. In the midday sector the peak-to-peak variation of the FAC latitude over the entire range of the dipole tilt is ∼5°, whereas it is ∼4° around midnight. In the flank sectors the average FAC latitude is higher around the solstices than around the equinoxes irrespective of hemisphere. The corresponding dependence on the dipole clock angle can actually be found for almost all local time sectors, although the peak-to-peak variation of the expected semiannual variation, 2° around noon and &lt
    1° in other local time sectors, is smaller than that of the annual variation except for the flank sectors. A comparison with a model magnetic field strongly suggests that the dipole tilt effect on the magnetospheric configuration is the primary cause of the annual variation, whereas the semiannual variation is inferred to reflect the fact that geomagnetic activity tends to be higher around the equinoxes. The average dayside FAC intensity is larger in the summer hemisphere than in the winter hemisphere, which can be explained in terms of the seasonal variation of the ionospheric conductivity. The dayside R1 current intensity depends more strongly on the dipole tilt than the dayside R2 current intensity, and it changes by a factor of 2-3 over the entire range of the dipole tilt angle. In contrast, the annual variation of the nightside FAC intensity is more complicated, and the nightside R2 current seems to be more intense in the winter hemisphere than in the summer hemisphere. The dependence of the FAC intensity on the dipole clock angle is less significant especially for the R1 system. Nevertheless, the result suggests that the FAC tends to be more intense around the equinoxes, which is consistent with the semiannual variation of geomagnetic activity. Copyright 2005 by the American Geophysical Union.

    DOI: 10.1029/2004JA010634

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  • A penalized likelihood estimation on transcriptional module-based clustering Reviewed

    R Yoshida, S Imoto, T Higuchi

    COMPUTATIONAL SCIENCE AND ITS APPLICATIONS - ICCSA 2005, PT 3   3482   389 - 401   2005

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    In this paper, we propose a new clustering procedure for high dimensional microarray data. Major difficulty in cluster analysis of microarray data is that the number of samples to be clustered is much smaller than the dimension of data which is equal to the number of genes used in an analysis. In such a case, the applicability of conventional model-based clustering is limited by the occurence of overlearning. A key idea of the proposed method is to seek a linear mapping of data onto the low-dimensional subspace before proceeding to cluster analysis. The linear mapping is constructed such that the transformed data successfully reveal clusters existed in the original data space. A clustering rule is applied to the transformed data rather than the original data. We also establish a link between this method and a probabilistic framework, that is, a penalized likelihood estimation of the mixed factors model. The effectiveness of the proposed method is demonstrated through the real application.

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  • Residual bootstrapping and median filtering for robust estimation of gene networks from microarray data Reviewed

    S Imoto, T Higuchi, SY Kim, E Jeong, S Miyano

    COMPUTATIONAL METHODS IN SYSTEMS BIOLOGY   3082   149 - 160   2005

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    We propose a robust estimation method of gene networks based on microarray gene expression data. It is well-known that microarray data contain a large amount of noise and some outliers that interrupt the estimation of accurate gene networks. In addition, some relationships between genes are nonlinear, and linear models thus are not enough for capturing such a complex structure. In this paper, we utilize the moving boxcel median filter and the residual bootstrap for constructing a Bayesian network in order to attain robust estimation of gene networks. We conduct Monte Carlo simulations to examine the properties of the proposed method. We also analyze Saccharomyces cerevisiae cell cycle data as a real data example.

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  • Two Methods of Pi2 Onset Time Determination with Information Criterion Based on the State Space and Bayesian Modelings Reviewed

    FUKUYAMA Keiko, HIGUCHI Tomoyuki, UOZUMI Teiji, KAWANO Hideaki, YUMOTO Kiyohumi

    The Transactions of the Institute of Electronics, Information and Communication Engineers A   87 ( 12 )   1502 - 1510   2004.12

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  • A new approach to time-dependent inversion of geodetic data using a Monte Carlo mixture Kalman filter Reviewed

    J Fukuda, T Higuchi, S Miyazaki, T Kato

    GEOPHYSICAL JOURNAL INTERNATIONAL   159 ( 1 )   17 - 39   2004.10

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    In the last decade, continuous Global Positioning System (GPS) networks have observed transient crustal deformation associated with various types of aseismic fault-slip event in many subduction zones. It is important to precisely clarify the entire time history of these events to understand the physical process of earthquake generation. For this purpose, we have developed a new time-dependent inversion method for imaging transient fault slips from geodetic data. Segall & Matthews (1997) presented a time-dependent inversion method to infer the spatiotemporal distribution of fault slip from geodetic data. They modelled a transient crustal deformation associated with fault-slip events using a linear Gaussian state space model and employed a Kalman filter. They introduced a scaling parameter that represents the temporal smoothness of the fault slip, and assumed that the scaling parameter is constant over the observation period. Under this assumption, abrupt changes of slip have been overly smoothed, whereas estimated slips in a 'quiet' steady-state period have been oscillatory. To improve the method, we developed a new filtering technique, a Monte Carlo mixture Kalman filter (MCMKF), and apply it to time-dependent inversion. The MCMKF allows variations of the temporal smoothness of slips by regarding it as a stochastic variable. The MCMKF is based on a Monte Carlo method in which conditional probability density functions of the stochastic variable are estimated recursively. We examine the validity of the introduced MCMKF-based inversion scheme through numerical experiments using simulated displacement time-series. Then, the results are compared with those obtained by a conventional Kalman filter-based scheme. In all cases, MCMKF gives a significantly smaller Akaike information criterion (AIC) values than the Kalman filter. This indicates that MCMKF yields better state estimates than the Kalman filter. We also find that MCMKF is capable of imaging the initiation process of transient slip events in cases with a high signal-to-noise ratio, while the Kalman filter is not. Furthermore, MCMKF is superior to the Kalman filter in detecting small signals from noisy data sets. From all of the results above, we conclude that the new filtering approach introduced here may provide a powerful tool for imaging the time history of fault slips.

    DOI: 10.1111/j.1365-246X.2004.02383.x

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  • Adjustment of Sampling Locations in Rail-Geometry Datasets : Using Dynamic Programming and Non-linear Filtering Reviewed

    KAMIYAMA Masako, HIGUCHI Tomoyuki

    The Transactions of the Institute of Electronics,Information and Communication Engineers.   87 ( 6 )   1199 - 1207   2004.6

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  • 状態空間モデルを用いた飲食店売上の要因分解 Reviewed

    山口類, 土屋映子, 樋口知之

    オペレーションズ・リサーチ : 経営の科学   49 ( 5 )   316 - 324   2004.5

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  • Combining microarrays and biological knowledge for estimating gene networks via Bayesian networks Reviewed

    Seiya Imoto, Tomoyuki Higuchi, Takao Goto, Kousuke Tashiro, Satoru Kuhara, Satoru Miyano

    Journal of Bioinformatics and Computational Biology   2 ( 1 )   77 - 98   2004.3

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    We propose a statistical method for estimating a gene network based on Bayesian networks from microarray gene expression data together with biological knowledge including protein-protein interactions, protein-DNA interactions, binding site information, existing literature and so on. Microarray data do not contain enough information for constructing gene networks accurately in many cases. Our method adds biological knowledge to the estimation method of gene networks under a Bayesian statistical framework, and also controls the trade-off between microarray information and biological knowledge automatically. We conduct Monte Carlo simulations to show the effectiveness of the proposed method. We analyze Saccharomyces cerevisiae gene expression data as an application. © Imperial College Press.

    DOI: 10.1142/S021972000400048X

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  • Statistical inference using stochastic switching models for the discrimination of unobserved display promotion from POS data Reviewed

    T Sato, T Higuchi, G Kitagawa

    MARKETING LETTERS   15 ( 1 )   37 - 60   2004.2

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    The execution of price and/or display promotion has a significant effect on the sales of a brand sold in a supermarket. Information on price and/or sales is available from POS data. However, unless an investigator collects information on the execution of display promotions from every retail store, such information is unavailable. This paper presents a method of identifying whether display promotion has been executed without having to visit individual stores. We treat the execution/non-execution of a display promotion as a state variable. An unknown stationary probability matrix is assumed to describe the probability of a transition between states. Each state is characterized by a different stationary time series model with unknown parameters. The objective of the analysis is to identify the model and to assign a probability model for each state at each time instant. Finally, we provide a high precision estimator of a past execution/non-execution of a display promotion based on the proposed model.

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  • A mixed factors model for dimension reduction and extraction of a group structure in gene expression data Reviewed

    R Yoshida, T Higuchi, S Imoto

    2004 IEEE COMPUTATIONAL SYSTEMS BIOINFORMATICS CONFERENCE, PROCEEDINGS   161 - 172   2004

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    When we cluster tissue samples on the basis of genes, the number of observations to be grouped is much smaller than the dimension of feature vector In such a case, the applicability of conventional model-based clustering is limited since the high dimensionality of feature vector leads to overfitting during the density estimation process. To overcome such difficulty, we attempt a methodological extension of the factor analysis. Our approach enables us not only to prevent from the occurrence of overfitting, but also to handle the issues of clustering, data compression and extracting a set of genes to be relevant to explain the group structure. The potential usefulness are demonstrated with the application to the leukemia dataset.

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  • A mixed factors model for dimension reduction and extraction of a group structure in gene expression data Reviewed

    R Yoshida, T Higuchi, S Imoto

    2004 IEEE COMPUTATIONAL SYSTEMS BIOINFORMATICS CONFERENCE, PROCEEDINGS   161 - 172   2004

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE COMPUTER SOC  

    When we cluster tissue samples on the basis of genes, the number of observations to be grouped is much smaller than the dimension of feature vector In such a case, the applicability of conventional model-based clustering is limited since the high dimensionality of feature vector leads to overfitting during the density estimation process. To overcome such difficulty, we attempt a methodological extension of the factor analysis. Our approach enables us not only to prevent from the occurrence of overfitting, but also to handle the issues of clustering, data compression and extracting a set of genes to be relevant to explain the group structure. The potential usefulness are demonstrated with the application to the leukemia dataset.

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  • Lower mantle conductivity anomalies estimated from geomagnetic jerks

    NAGAO H, IYEMORI T, HIGUCHI T, ARAKI T

    J Geophys Res   108 ( B5 )   EPM8.1-EPM8.18   2003.5

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  • Lower mantle conductivity anomalies estimated from geomagnetic jerks Reviewed

    H Nagao, T Iyemori, T Higuchi, T Araki

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   108 ( B5 )   2003.5

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    [1] The occurrence epochs and duration periods of the 1969, 1978, and 1991 geomagnetic jerks are estimated for 65 geomagnetic observatories by applying a statistical time series model to monthly means of the geomagnetic eastward component. It is found for every jerk that the occurrence epochs around South Africa and South Pacific Ocean are delayed several years from those in other regions. Moreover, it is found for the 1969 and 1978 jerks that the duration times around South Africa, which are defined as the lengths of the duration periods, are longer than those in other regions. The distribution of these anomalous regions of the jerks (i.e., South Africa and South Pacific Ocean) may imply the existence of higher conductivities in the lower mantle beneath these regions, which possibly relates to the fact that the velocity of a seismic S wave in the D" layer beneath these regions is slower than that in other regions. The mantle conductivities beneath South Africa, South Pacific Ocean, and other regions are estimated through a numerical simulation; the magnetic diffusion equation in the mantle is solved for an abrupt magnetic change generated at the core-mantle boundary. Comparing the results obtained by the simulation with those obtained by the data analysis, it is plausible that the mantle conductivities beneath South Africa and South Pacific Ocean are higher than that beneath other regions, although there is an ambiguity in the estimated magnitudes of the mantle conductivity.

    DOI: 10.1029/2002JB001786

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  • Smoothness prior approach to explore mean structure in large-scale time series Reviewed

    G Kitagawa, T Higuchi, FN Kondo

    THEORETICAL COMPUTER SCIENCE   292 ( 2 )   431 - 446   2003.1

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    This article is addressed to the problem of modeling and exploring mean value structure of large-scale time series data and time-space data. A smoothness prior modeling approach (Smoothness Prior Analysis of Time Series, Lecture Notes in Statistics, vol. 116, Springer, New York, 1996.) is taken. In this approach, the observed series are decomposed into several components each of which are expressed by smoothness priors models. In the analysis of POS and GPS data, various useful information were extracted by this decomposition, and result in discoveries in these areas. (C) 2002 Elsevier Science B.V. All rights reserved.

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  • Combining microarrays and biological knowledge for estimating gene networks via Bayesian networks Reviewed

    S Imoto, T Higuchi, T Goto, K Tashiro, S Kuhara, S Miyano

    PROCEEDINGS OF THE 2003 IEEE BIOINFORMATICS CONFERENCE   2   104 - 113   2003

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    We propose a statistical method for estimating a gene network based on Bayesian networks from microarray gene expression data together with biological knowledge including protein-protein interactions, protein-DNA interactions, binding site information, existing literature and so on. Unfortunately, microarray data do not contain enough information for constructing gene networks accurately in many cases. Our method adds biological knowledge to the estimation method of gene networks under a Bayesian statistical framework; and also controls the trade-off between microarray information and biological knowledge automatically. We conduct Monte Carlo simulations to show the effectiveness of the proposed method We analyze Saccharomyces cerevisiae gene expression data as an application.

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  • Local time features of geomagnetic jerks Reviewed

    H Nagao, T Iyemori, T Higuchi, S Nakano, T Araki

    EARTH PLANETS AND SPACE   54 ( 2 )   119 - 131   2002

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    The geomagnetic jerk amplitudes, which are defined as abruptness of changes in the trends of geomagnetic time series, are investigated with geomagnetic monthly means computed from hourly mean values at each local time. A statistical time series model in which the trend component is expressed by a second order spline function with variable knots is constructed for each time series. The optimum parameter values of the model including positions of knots are estimated by the maximum likelihood method, and the optimum number of parameters including the number of knots are determined based on the Akaike Information Criterion (AIC). The jerks are detected objectively and automatically by regarding the optimized positions of knots as the occurrence epochs. This analysis reveals that the spatial distributions of jerk amplitudes essentially do not depend on the local time, which indicates that the jerks cannot be explained by abrupt changes in intensities of latitudinally flowing external currents such as the field-aligned currents. Longitudinally flowing currents, on the other hand, such as the ring current could explain the distributions. The abrupt changes of the ring current intensity are estimated from the distributions of jerk amplitudes in the eastward component in 1969, 1978, and 1991 supposing that an abrupt change in the ring current intensity causes a jerk. However those estimated changes cannot consistently explain the distributions of the jerks in the northward and downward components. Therefore it is plausible that the jerks which occur-red in 1969, 1978, and 1991 are not caused by external sources but internal ones. It is also confirmed that the occurrence epochs of jerks in the southern hemisphere are a few years after those of the 1969 and 1978 jerks in the northern hemisphere. and it is also found that the jerk in the southern hemisphere occurred a few years after the occurrence of the 1991 jerk in Europe. Taking these time tags in occurrence epochs into account, it can be said that the 1969, 1978, and 1991 jerks are global phenomena.

    DOI: 10.1186/BF03351712

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  • Maneuvering target tracking by using particle filter method with model switching structure Reviewed

    N Ikoma, T Higuchi, H Maeda

    COMPSTAT 2002: PROCEEDINGS IN COMPUTATIONAL STATISTICS   431 - 436   2002

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    Tracking problem of maneuvering target is treated with assumption that the maneuver is unknown and its acceleration has abrupt changes sometimes. To cope with unknown maneuver, Bayesian switching structure model, which includes a set of possible models and switches among them, is used. It can be formalized into general (nonlinear, non-Gaussian) state space model where system model describes the target dynamics and observation model represents a process to observe the target position. Heavy-tailed uni-modal distribution, e.g. Cauchy distribution, is used for the system noise to accomplish good performance of tracking both for constant period and abrupt changing time point of acceleration. Monte Carlo filter, which is a kind of particle filter that approximates state distribution by many particles in state space, is used for the state estimation of the model. A simulation study shows the efficiency of the proposed model by comparing with Gaussian case of Bayesian switching structure model.

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  • Monte Carlo Strategies in Scientific Computing

    Higuchi Tomoyuki

    Bulletin of the Japan Society for Industrial and Applied Mathematics   12 ( 2 )   216 - 217   2002

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    DOI: 10.11540/bjsiam.12.2_216

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  • Computational methods for time series analysis Reviewed

    G Kitagawa, T Higuchi, S Sato

    COMPSTAT 2002: PROCEEDINGS IN COMPUTATIONAL STATISTICS   15 - 24   2002

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    By the progress of fast computing facilities and various computing technologies, it becomes realistic to apply computer intensive methods to statistical analysis. In time series analysis, sequential Monte Carlo methods was developed for general state space models which enables to consider very complex nonlinear non-Gaussian models.
    In this paper, we show algorithms, implementations and parameter estimation for Monte Carlo filter and smoother. Various ways of the use of parallel computer. are also discussed. The usefulness of the general state space modeling is illustrated with several examples.

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  • Application of multivariate Maxwellian mixture model to plasma velocity distribution Reviewed

    Ueno, Genta, Nagatomo Nakamura, Tomoyuki Higuchi, Takashi Tsuchiya, Shinobu Machida, Tohru Araki

    Progress in Discovery Science, (Lecture Notes in Computer Science)   2281   372 - 383   2002

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    DOI: 10.1007/3-540-45884-0_27

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  • Automatic detection of geomagnetic jerks by applying a statistical time series model to geomagnetic time series Reviewed

    Nagao, H, T. Higuchi, T. Iyemori, T. Araki

    Lecture Notes in Artificial Intelligence   2281   360 - 371   2002

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    DOI: 10.1007/3-540-45884-0_26

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  • Application of multivariate Maxwellian mixture model to plasma velocity distribution function Reviewed

    G Ueno, N Nakamura, T Higuchi, T Tsuchiya, S Machida, T Araki, Y Saito, T Mukai

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   106 ( A11 )   25655 - 25672   2001.11

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    Recent space plasma observations have provided us with three-dimensional velocity distributions having multiple peaks. We propose a method for analyzing such velocity distributions via a multivariate Maxwellian mixture model where each component of the model represents each of the multiple peaks. The parameters of the model are determined through an iterative nonlinear optimization technique, specifically the expectation-maximization (EM) algorithm. For the automatic judgment of the preferable number of components in the mixture model, we introduce a method of examining the number of extrema of a resulting mixture model. We show applications of our method to ion observations in the plasma sheet boundary layer (PSBL) and in the central plasma sheet (CPS) of the Earth's magnetotail. From an analysis of the PSBL and CPS, low-energy ions that have properties similar to those of lobe ions were detected also in the PSBL and CPS. In the PSBL, middle-energy ion component which is flowing dawnward and directed the neutral sheet was extracted. We suggested that magnetic field fluctuations in the PSBL can be explained only when the two ion components were properly treated.

    DOI: 10.1029/2001JA900079

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  • Evolutionary Time Series Model With Parallel Computing

    Tomoyuki Higuchi

    The Third JAPAN-US Joint Seminar on Statistical Time Series Analysis   183 - 190   2001

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    In this study,we consider a time series model which combines the partial nonGaussian state space model and self-organizing state space model (SOSSM), where the SOSSM has been proposed to an extension of the generalized state space model. The competing different system/observation models for the state vector can be simultaneously dealt in this model as introducing a switching structure, and appropriate system/observation models among them is automatically determined as a function of time. As a result, we are free from a procedure of selecting models among competing models. Of course, this model allows us to consider an inclusion of two system/observation models which conflicts each other in some sense. Namely,we need not havewell-organized knowledge about modeling of the time series. We therefore call this model the evolutionary time series model. We regard the approach based on the evolutionary time series model as one of the machine learning approaches. The evolutionary time series model can be formulated within a framework of an extension of SOSSM whichtakes a convenient form from a computational point of view.

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  • Separation of photoelectrons via multivariate Maxwellian mixture model Reviewed

    Genta Ueno, Nagatomo Nakamura, Tomoyuki Higuchi

    The proceedings of The Forth International Conference on Discovery Science,   2226   470 - 475   2001

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    Abstract. Electron velocity distribution obtained by direct spacecraft observation in space is contaminated by photoelectrons. The photoelectrons are generated due to the solar ultraviolet ray, and are regarded as artificial noise from a viewpoint of scientific research. We propose a method for separating photoelectron component from ambient electron component. Our method uses multivariate normal mixture model, whose parameters are determined via the Expectation-Maximization (EM) algorithm. Initial parameters of the EM algorithm are computed through the classification of the velocity space by a spherical surface of some arbitrary radius. 1

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  • Automatic identification of large-scale field-aligned current structures Reviewed

    T Higuchi, S Ohtani

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   105 ( A11 )   25305 - 25315   2000.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    The study of large-scale field-aligned currents (LSFACs) has depended on visual inspection of data plots, which is often subjective and time-consuming, and therefore limits the efficiency of analyses. The present paper reports a new procedure to automatically identify the spatial structure of LSFACs from satellite magnetic field measurements. The procedure is based on the concept of the first-order B spline fitting with variable node positions, which may be envisioned as fitting line segments to a line plot. The fitting is made for the maximum variance component of magnetic variations in the plane perpendicular to the background magnetic field. If the distribution of LSFACs can be approximated as an infinite sheet, each slope of the plot corresponds to the crossing of a FAC sheet. The number of node points, which determines the number of FAC sheets, is one of the fitting parameters and is optimized for each orbit so that the Akaike information criterion (AIC) is minimized. Whereas other methods, such as a spherical harmonic fitting, seek to obtain two-dimensional distributions of FACs from assembled data, the present method is basically the automation of the way we visually examine a plot of satellite magnetic field data, and it can be applied even to a single satellite pass. Therefore the procedure can be implemented to real-time data processing and now-casting. The procedure should also provide a powerful tool for data mining. Magnetic field data from the Defense Meteorological Satellite Program-F7 (DMSP-F7) were used for demonstration, and the present paper reports the initial results.

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  • Four-sheet structures of dayside field-aligned currents: Statistical study Reviewed

    S Ohtani, T Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   105 ( A11 )   25317 - 25324   2000.11

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    The present study investigates the statistical characteristics of four-sheet structures of large-scale field aligned currents (FACs) observed by the Defense Meteorological Satellite Program-F7 (DMSP-F7) satellite in the dayside high-latitude region. A total of 495 four-FAG-sheet events were selected from the entire set of DMSP-F7 magnetometer data. With respect to the polarity of FACs, the selected events are classified into two groups, which are named type M and type W after the shape of a plot of the azimuthal magnetic component. The polarity of the equatorward most FAC is downward for the type M structure, whereas it is upward for the type W structure. Type W and type M events tend to take place in the prenoon and postnoon sectors, respectively, but the transition takes place slightly before noon. The type W structure tends to be observed for negative and positive interplanetary magnetic field (IMF) B-y,in the Northern and Southern Hemispheres, respectively. For a given hemisphere, the favorable sign of IMF B-Y, for the type M structure is opposite to that for the type W structure. It is also found that both types occur more often when the IMF B-Z, is northward than when it is southward. The four-sheet structure can be interpreted in terms of two zonal ionospheric convection flows separated in latitude. The equatorward one is a part of the viscous cell and, possibly, also the merging cell, whereas the poleward one is a part of the lobe cell. The direction (of the major cell) of the lobe convection is determined by the sign of IMF By and is different in different hemispheres, explaining the discovered IMF B-Y dependence. The preference for northward IMF B-Z, is consistent with the required development of the lobe convection. It is inferred from the expected polar distribution of FACs that the four-sheet structure is a superposition of a pair of midday region 0 and region 1 currents and a pair of conventional region 1 and region 2 currents.

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  • Application of Multivariate Maxwellian Mixture Model to Plasma Velocity Distribution Function Reviewed

    Genta Ueno, Nagamoto Nakamura, Tomoyuki Higuchi, Takashi Tuschiya, Shinobu Machida, Tohru Araki

    Progresses in Discovery Sience, Final Report of the Japanese Discovery Science Project   1967   382 - 383   2000

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  • Automatic identification of large-scale field-aligned current structures and its application to night-side current systems Reviewed

    T Higuchi, S Ohtani

    MAGNETOSPHERIC CURRENT SYSTEMS   118   389 - 394   2000

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:AMER GEOPHYSICAL UNION  

    The present paper reports a newly developed procedure to automatically identify : a spatial structure of large-scale field-aligned currents (FACs) from satellite magnetic field measurements. The procedure is based on the concept of the first-order B-spline fitting with variable (i.e., movable) node positions, which may be envisioned as fitting line segments to a,plot of a magnetic field component. The number of node points is optimized for each current sheet crossing so that a certain information criterion is minimized. The properties of a FAC system such as its location and intensity can be easily calculated from the information of node points. The procedure is applied to the entire set of nightside magnetic field measurements (1339 days) made by the DMSP-F7 satellite and for demonstration, the intensity of nightside region-1 FACs is examined as a function of magnetic latitude. The results not only confirm the general expectation that intense region 1 currents tend to be observed at lower latitudes but also quantify the relationship between the current intensity and latitude. The capability of such quantification should be useful for future studies including practical applications such as space weather forecast.

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  • Disappearance of large-scale field-aligned,current systems: Implications for the solar wind-magnetosphere coupling Reviewed

    S Ohtani, T Higuchi

    MAGNETOSPHERIC CURRENT SYSTEMS   118   253 - 259   2000

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    Large-scale field-aligned current (FAC) systems occasionally disappear in the midday sector (9 &lt; MLT &lt; 13), even though this is the local time sector where FACs tend to be most intense. The present study investigates 26 such events observed by the DMSP-F7 satellite. It is found that the events tend to occur in the winter hemisphere in a certain UT range when the dipole axis was inclined most antisunward and therefore the contribution of solar illumination to the ionospheric conductivity is minimum. Before most events, IMF B(Z) was positive, and the solar wind bulk flow momentum was below the average. Although one might expect to see such events when the sign of B(X) was unfavorable for merging at the high-latitude tail magnetopause in the winter hemisphere, no clear preference for IMF B(X) was found. It was also found that the asymmetry of the ionospheric conductivity between the summer and winter hemispheres suppresses the IMF-dependent characteristics of particle precipitation in the polar cap. These results suggest that ionospheric conductivity not only determines the intensity of FACs for the convection electric field imposed by the solar wind-magnetosphere interaction, but also affects how the magnetosphere interacts with the solar wind.

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  • Detection of the structure of particle velocity distribution by finite mixture distribution model Reviewed

    G Ueno, S Machida, N Nakamura, T Higuchi, T Araki

    DISCOVERY SCIENCE, PROCEEDINGS   1721   366 - 368   1999

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG BERLIN  

    DOI: 10.1007/3-540-46846-3_51

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  • Smoothness prior approach to explore the mean structure in large time series data Reviewed

    G Kitagawa, T Higuchi, FN Kondo

    DISCOVERY SCIENCE, PROCEEDINGS   1721   230 - 241   1999

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG BERLIN  

    This article is addressed to the problem of modeling and exploring time series with mean value structure of large scale time series data and time-space data. A smoothness priors modeling approach [11] is taken and applied to POS and GPS data. In this approach, the observed series are decomposed into several components each of which are expressed by smoothness priors models. In the analysis of POS and GPS data, various useful information were extracted by this decomposition, and result in some discoveries in these areas.

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  • Automatic transaction of signal via statistical modeling Reviewed

    G Kitagawa, T Higuchi

    DISCOVERY SCIENCE   1532   375 - 386   1998

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER-VERLAG BERLIN  

    The statistical information processing can be characterized by using the Likelihood function defined by giving an explicit form for an approximation to the true distribution from which the data are generated. This mathematical representation as an approximation, which is usually called a model, is built based on not only the current data but also prior knowledge on the object and the objective of the analysis. Akaike ([2] and [3]) showed that the log-likelihood can be considered as an estimate of the Kullback-Leibler information which defines the similarity between the predictive distribution of the model and the true distribution and proposed the Akaike information criterion (AIC). By the use of this AIC, it becomes possible to evaluate and compare the goodness of many models objectively and it enables us to select the best model among many candidates. In consequence, the minimum AIC procedure allows us to develop automatic modeling and signal extraction procedures. In this study, we give a simple explanation of statistical modeling based on the AIC and demonstrate four examples of applying the minimum AIC procedure to an automatic transaction of signals observed in the earth sciences. In each case, the AIC plays an important role in making the procedure automatic and objective, and promises to realize a detail examination of a large amount of data sets, which provides us with an opportunity to discover new information.

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  • A generalization of the minimum variance analysis method Reviewed

    H. Kawano, T. Higuchi

    Annales Geophysicae   14 ( 10 )   1019 - 1024   1996

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:European Geosciences Union  

    In order to determine the normal direction of the magnetopause, the minimum variance analysis technique is frequently used: it is applied to the magnetic field data of a magnetopause crossing observed by a satellite, and provides the direction along which the magnetic field variation is minimum. In this study we propose a method to extend naturally the framework of the minimum variance analysis so that it includes all continuity conditions across a planar magnetopause, so that we could use all physical quantities observed by the spacecraft. We first extend it to the electric field: we discuss how to determine the normal direction and the speed of the magnetopause along the normal by using both the magnetic and electric field data. We next discuss the full extension to all continuity conditions across the magnetopause. Finally, we discuss how to extend our method further so that it can deal with the magnetopause which is accelerating. A discussion of application to observations will appear separately.

    DOI: 10.1007/s00585-996-1019-1

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  • The bootstrap method in space physics: Error estimation for the minimum variance analysis Reviewed

    H. Kawano, T. Higuchi

    Geophysical Research Letters   22 ( 3 )   307 - 310   1995

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    The minimum variance analysis technique introduced by Sonnerup and Cahill (1967) is a useful tool in space physics. However the statistical errors appearing in this method are difficult to estimate accurately because of the complicated form of the eigenvalue decomposition. To deal with this problem, this paper introduces the bootstrap method (Efron, 1979) which replaces analytical solutions with repeated simple calculations. We apply this method to the estimation of the statistical errors in the minimum variance direction and the average component in the minimum variance direction, and show that this method accurately estimates the errors. Copyright 1995 by the American Geophysical Union.

    DOI: 10.1029/94GL02969

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  • Self-organizing time series model Reviewed

    Tomoyuki Higuchi

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    1.1 Generalized state space model The generalized state space model (GSSM) that we deal with in this study is de ned by a set of two equations system model xt = f(xt;1 � vt) � and (1.1)

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Books

  • 予測にいかす統計モデリングの基本 改訂第2版 ベイズ統計入門から応用まで (KS理工学専門書)

    樋口 知之( Role: Sole author)

    講談社  2022.7  ( ISBN:4065285704

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    Total pages:176   Language:Japanese  

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  • 教養としてのデータサイエンス (データサイエンス入門シリーズ)

    内田 誠一, 川崎 能典, 孝忠 大輔, 佐久間 淳, 椎名 洋, 中川 裕志, 樋口 知之, 丸山 宏, 樋口, 知之, 丸山, 宏

    講談社  2021.6  ( ISBN:4065238099

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    Total pages:240   Language:Japanese  

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  • ベイズモデリングの世界

    樋口 知之( Role: Joint author全体モデルから局所モデルへ)

    岩波書店  2018.1  ( ISBN:9784000247986

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    Total pages:14   Responsible for pages:pp.55-68   Language:Japanese  

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  • ブランド評価手法: ―マーケティング視点によるアプローチ― (シリーズ“マーケティング・エンジニアリング”)

    守口 剛, 佐藤 忠彦, 里村 卓也, 樋口 知之, 鶴見 裕之, 佐藤 栄作( Role: Joint authorベイジリアン・モデリングによる動的ブランド診断)

    朝倉書店  2014.12  ( ISBN:4254295057

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    Total pages:170   Responsible for pages:pp.122-145   Language:Japanese  

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  • 現象数理学入門

    斎藤正也, 樋口知之, 三村 昌泰( Role: Contributor伝播の現象数理-インフルエンザ・パンデミック)

    東京大学出版会  2013.9  ( ISBN:4130629166

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    Total pages:203   Responsible for pages:pp145-168  

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  • ビッグデータ時代のマーケティング―ベイジアンモデリングの活用 (KS社会科学専門書)

    佐藤忠彦, 樋口知之

    講談社  2013.2  ( ISBN:9784061573024

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    Total pages:209  

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  • サービス工学の技術 : ビッグデータの活用と実践

    本村陽一, 竹中毅, 石垣司, 樋口知之( Role: Contributor第6章 データ同化によるシミュレーション計算と大規模データ解析の融合)

    東京電機大学出版局  2012.11  ( ISBN:9784501551001

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    Total pages:xii, 204p   Language:Japanese  

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  • データ同化入門 (予測と発見の科学)

    樋口知之, 樋口知之( Role: Edit)

    朝倉書店  2011.9  ( ISBN:4254127863

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    Total pages:256  

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  • 予測にいかす統計モデリングの基本―ベイズ統計入門から応用まで (KS理工学専門書)

    樋口 知之

    講談社  2011.4  ( ISBN:4061557955

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    Total pages:158  

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  • 超多自由度系の新しい科学

    笹井 理生, 樋口知之( Role: Contributor第5章 何を計算するか)

    共立出版  2010.11  ( ISBN:9784320122758

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    Total pages:x, 323p, 図版 [2] p   Language:Japanese  

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  • 動的売上モデルによる小売価格戦略の評価−状態空間モデルの適用−、 シリーズ ビジネスの数理第7巻 マーケティング・経営戦略の数理

    佐藤 忠彦, 樋口 知之

    朝倉書店  2009 

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  • パターン認識と機械学習 下 - ベイズ理論による統計的予測

    C. M. ビショップ

    シュプリンガー・ジャパン株式会社  2008.7  ( ISBN:4431100318

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    Total pages:433  

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  • パターン認識と機械学習 上 - ベイズ理論による統計的予測

    C. M. ビショップ

    シュプリンガー・ジャパン株式会社  2007.12  ( ISBN:443110013X

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    Total pages:349  

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  • 統計数理は隠された未来をあらわにする―ベイジアンモデリングによる実世界イノベーション

    樋口 知之, 照井 伸彦, 井元 清哉, 北川 源四郎, 石井 信

    東京電機大学出版局  2007.6  ( ISBN:4501543302

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    Total pages:136  

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  • モデルヴァリデーション (データサイエンス・シリーズ)

    北川 源四郎, 樋口 知之, 川崎 能典, 岸野 洋久, 山下 智志

    共立出版  2005.3  ( ISBN:4320120043

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    Total pages:210  

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  • ゆらぎの科学と技術 : フラクチュオマティクス入門

    山本 光璋, 鷹野 致和, 樋口知之( Role: Contributor組織的な発見への期待と予感)

    東北大学出版会  2004.9  ( ISBN:4925085905

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    Total pages:vii, 262p   Language:Japanese  

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  • Self-organizing Time Series Model

    Tomoyuki HIGUCHI( Role: Joint authorSequential Monte Carlo Methods in Practice)

    Springer-Verlag New York  2001 

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    Responsible for pages:pp429-444   Language:English  

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  • The Practice of Time Series Analysis (Information Science and Statistics)

    H. Akaike, G. Kitagawa, T. Higuchi( Role: ContributorProcessing of Time Series Data Obtained by Satellites)

    Springer-Verlag New York  1999 

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  • 時系列解析の実際II

    赤池 弘次, 北川 源四郎, 樋口 知之( Role: Contributor人工衛星時系列データの処理)

    朝倉書店  1995.1  ( ISBN:9784254122473

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    Total pages:2冊   Language:Japanese  

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MISC

  • AI・データサイエンス全学プログラム Invited

    樋口 知之

    大学時報   404   54 - 59   2022.5

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (bulletin of university, research institution)   Publisher:一般財団法人 日本私立大学連盟  

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  • 感染症とデータ駆動型社会 Invited

    樋口知之

    月刊 統計   71 ( 12 )   2 - 3   2020.12

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (other)   Publisher:一般財団法人 日本統計協会  

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  • ムーアの法則を超える論文数 Invited

    樋口 知之

    化学と工業   72 ( 9 )   747 - 747   2019.9

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  • Possibility for Technological Innovation in Construction Employing Statistical Mathematics Approaches Invited

    Tomoyuki HIGUCHI

    STEEL CONSTRUCTION TODAY & TOMORROW   ( 54 )   15 - 18   2018.8

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    Language:English   Publishing type:Article, review, commentary, editorial, etc. (other)  

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  • 地震予測と「第4の科学」-データに駆動された新たなアプローチへ(後編) Invited

    尾池和夫, 金田義行, 北川源四郎, 鳥海光弘, 樋口知之

    科学   88 ( 6 )   563 - 569   2018.6

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  • 地震予測と「第4の科学」-データに駆動された新たなアプローチへ(前編) Invited

    尾池和夫, 金田義行, 北川源四郎, 鳥海光弘, 樋口知之

    科学   88 ( 5 )   489 - 498   2018.5

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  • データ関連の数理技術の変遷:深層学習は春秋戦国時代の秦となるのか? Invited

    樋口 知之

    人工知能   33 ( 2 )   116 - 123   2018.3

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  • 爆速化する研究スピード Invited

    樋口 知之

    数学セミナー   56 ( 12 )   1   2017.12

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  • ビッグデータ時代に対応した高度人材育成を牽引 Invited

    樋口知之, 神谷直樹

    文部科学教育通信   ( 426 )   22 - 24   2017.12

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  • シミュレーション,データ同化,そしてエミュレーション Invited

    樋口知之

    岩波データサイエンス   6   98 - 105   2017.6

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  • 人工知能と教育 Invited

    樋口知之

    数学セミナー   56 ( 6 )   1   2017.4

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  • Citizen Science: Mutual surveillance or co-evolution? Invited

    HIGUCHI Tomoyuki

    Journal of Information Processing and Management   59 ( 9 )   629 - 635   2016.12

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (other)   Publisher:Japan Science and Technology Agency  

    DOI: 10.1241/johokanri.59.629

    CiNii Books

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    Other Link: http://search.jamas.or.jp/link/ui/2017054109

  • 人工知能はみようみまねマシンの究極形

    樋口知之

    情報管理   59 ( 5 )   331 - 335   2016.8

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (other)  

    DOI: 10.1241/johokanri.59.331

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  • Interview データで見えないものを知る 人工知能の背後に統計あり! 樋口知之 統計数理研究所所長 (特集 ビジネス数学の最終兵器 確率・統計入門) -- (もっと使える! 確率・統計 魔法の「べイズ統計」)

    樋口 知之

    週刊ダイヤモンド   104 ( 26 )   55 - 55   2016.7

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    Language:Japanese   Publisher:ダイヤモンド社  

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  • 集計位置データからの人流のリアルタイム推定のための粒子フィルタの提案と東日本大震災への応用

    須藤明人, 樫山武浩, 矢部貴大, 金杉洋, SONG Xuan, 樋口知之, 中野慎也, 斎藤正也, 関本義秀

    情報処理学会シンポジウムシリーズ(CD-ROM)   2016 ( 1 )   922‐924   2016.6

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    J-GLOBAL

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  • Scientific senses and skills necessary for promoting the data-driven science and technology : Stochastic modeling, Statistical thinking, and Inverse analysis Invited

    HIGUCHI Tomoyuki

    Journal of Information Processing and Management   59 ( 1 )   53 - 56   2016.4

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (scientific journal)   Publisher:Japan Science and Technology Agency  

    DOI: 10.1241/johokanri.59.53

    CiNii Books

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    Other Link: https://jlc.jst.go.jp/DN/JLC/20022241236?from=CiNii

  • スモールデータ、ビッグデータ、そしてスマートデータ-人工知能ブームの中での統計学- Invited

    樋口知之

    統計   67 ( 1 )   9 - 14   2016.1

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  • Big Impact of Big Data on Our Daily Life Invited

    99 ( 1 )   30 - 35   2016.1

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  • リアルタイムな広域人流推定のための高速で高精度な粒子フィルタの提案

    須藤明人, 樫山武浩, 矢部貴大, 樋口知之, 中野慎也, 斎藤正也, 関本義秀

    交通工学研究発表会論文集(CD-ROM)   36th   ROMBUNNO.88 - 578   2016

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  • 肺腺癌におけるβカテニンの活性化はイレッサ(gefitinib)への耐性に寄与する

    中田 飛鳥, 吉田 亮, 山口 類, 玉田 嘉紀, 藤田 アンドレ, 島村 徹平, 井元 清哉, 樋口 知之, 野村 将春, 木村 達郎, 軒原 浩, 東山 聖彦, 近藤 和也, 西原 広史, 東條 有伸, 矢野 聖二, 宮野 悟, 後藤 典子

    日本生化学会大会・日本分子生物学会年会合同大会講演要旨集   88回・38回   [3P1117] - [3P1117]   2015.12

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  • 機械エンジニアのためのビッグデータの基礎知識 Invited

    樋口 知之

    日本機械学会誌   118 ( 1163 )   610 - 615   2015.10

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  • 肺腺癌におけるβカテニンの活性化はイレッサ(gefitinib)への耐性に寄与する

    中田 飛鳥, 吉田 亮, 山口 類, 玉田 嘉紀, 藤田 アンドレ, 島村 徹平, 井元 清哉, 樋口 知之, 野村 将春, 木村 達郎, 軒原 浩, 東山 聖彦, 近藤 和也, 西原 広史, 東條 有伸, 矢野 聖二, 宮野 悟, 後藤 典子

    日本分子腫瘍マーカー研究会プログラム・講演抄録   35回   72 - 73   2015.9

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  • インフルエンザ流行対策への計算機シミュレーション活用へ向けての取り組み

    斎藤正也, 井元清哉, 山口類, 坪倉正治, 上昌広, 中田はる佳, 佐藤弘樹, 宮野悟, 樋口知之

    日本衛生学雑誌   70 ( Supplement )   S141   2015.3

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  • 統計学からのロボティクス研究への期待

    樋口 知之

    日本ロボット学会誌   33 ( 2 )   68 - 71   2015.3

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    DOI: 10.7210/jrsj.33.68

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  • Elevated β-catenin pathway as a novel target for patients with resistance to EGF receptor targeting drugs

    Nakata Asuka, Kimura Tatsuo, Nokihara Hiroshi, Higashiyama Masahiko, Kondoh Kazuya, Nishihara Hiroshi, Tojo Arinobu, Yano Seiji, Miyano Satoru, Gotoh Noriko, Yoshida Ryo, Yamaguchi Rui, Tamada Yoshinori, Fujita Andre, Shimamura Teppei, Imoto Seiya, Higuchi Tomoyuki, Nomura Masaharu

    Japan Journal of Molecular Tumor Marker Research   31 ( 0 )   46 - 47   2015

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    DOI: 10.11241/jsmtmr.31.46

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  • A developement of snowfall estimation model for Antarctica Part2. - Case studies for 2009 -

    鈴木香寿恵, 本山秀明, 本山秀明, 山内恭, 山内恭, 平沢尚彦, 平沢尚彦, 榎本浩之, 榎本浩之, 田村岳史, 田村岳史, 飯塚芳徳, 的場澄人, 樋口知之, 樋口知之

    雪氷研究大会講演要旨集(Web)   2015   63(J‐STAGE) - 63   2015

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    DOI: 10.14851/jcsir.2015.0_63

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  • Simulation and Big Data in Geosciences:Data Assimilation and Emulation

    Nakano S, Higuchi T

    The journal of institute of electronics, information and communication engineers   Vol.97 ( No.10 )   869 - 875   2014.10

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  • 南極氷床に適応した降雪量推定モデルの開発―降雪をもたらす大気循環場の特徴―

    鈴木香寿恵, 本山秀明, 山内恭, 榎本浩之, 田村岳史, 飯塚芳徳, 樋口知之

    雪氷研究大会講演要旨集   2014   235   2014.9

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  • Seeing Both the Forest and the Trees : Techniques for Analyzing Big Data

    ( 146 )   16 - 26   2014.8

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  • Estimation of the helium ion density distribution in the plasmasphere based on a single IMAGE/EUV image

    Nakano Shin'ya, Fok Mei-Ching, Brandt Pontus C son, Higuchi Tomoyuki

    Journal of Geophysical Research   119 ( 5 )   3724 - 3740   2014.5

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  • Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images

    Nakano Shin'ya, Fok Mei-Ching, Brandt Pontus C son, Higuchi Tomoyuki

    Journal of Geophysical Research   119 ( 5 )   3708 - 3723   2014.5

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  • The birth of statistical mathematics and its expanding world Invited

    Higuchi T

    Journal of transdisciplinary federation of science and technology   第8巻 ( 第1号 )   14 - 21   2014.4

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    This document gives a brief explanation for what is "Statistical Mathematics," and describeshow its notion has been expanding to a wide variety of research fields. The recent interests ofstatistical mathematics are focused on generating more flexible mathematical models for describingcomplex phenomena in terms of data generation mechanism and/or its function. Such efforts demandcollaborative works with the machine learning community in a big data era which we are now facedwith.

    DOI: 10.11487/trafst.8.1_14

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  • ビッグデータビジネス:新ビジネス創出の牽引者に Invited

    樋口 知之

    月刊金融ジャーナル   vol.55 ( No.1(689号) )   82 - 83   2014.1

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  • 南極氷床における降雪量推定モデルの開発―その1―

    鈴木香寿恵, 本山秀明, 平沢尚彦, 山内恭, 榎本浩之, 田村岳史, 飯塚芳徳, 的場澄人, 樋口知之

    極域科学シンポジウム講演予稿集(CD-ROM)   5th   ROMBUNNO.OM,12GATSU2NICHI,11:15   2014

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  • Marketing Models for Big Data : -Applicability of Data Assimilation Technique(<Special Feature>Big Data and Data Assimilation)

    Sato Tadahiko, Higuchi Tomoyuki

    Journal of the Japan Society for Simulation Technology   32 ( 4 )   306 - 312   2013.12

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  • Big Data and Data Assimilation(Review,<Special Feature>Big Data and Data Assimilation)

    Higuchi Tomoyuki, Nagao Hiromichi

    Journal of the Japan Society for Simulation Technology   32 ( 4 )   272 - 273   2013.12

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  • Design of Influenza Mitigation Program : Enhancement of Collective Immunity by Selective Distribution of Vaccines

    Saito Masaya M, Imoto Seiya, Yamaguchi Rui, Sato Hiroki, Nakada Haruka, Kami Masahiro, Tsubokura Masaharu, Miyano Satoru, Higuchi Tomoyuki

    シミュレーション   32 ( 4 )   281 - 286   2013.12

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  • カルマンフィルターを用いたドームふじ氷床コア年代決定モデルの開発

    鈴木香寿恵, 川村賢二, 中野慎也, FREDRIC PARRENIN, 阿部彩子, 齋藤冬樹, 樋口知之

    雪氷研究大会講演要旨集   2013   153 - 153   2013.9

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    DOI: 10.14851/jcsir.2013.0_153

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  • 2009年の日本におけるインフルエンザ動向における地域間相互作用の影響

    斎藤正也, 樋口知之, 井元清哉, 山口類, 坪倉正治, 上昌広, 中田はる佳, 宮野悟, 佐藤弘樹

    統計関連学会連合大会講演報告集   2013   281   2013.9

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  • Interview お粗末な「数字で語る」経営 経営者に統計リテラシーは必須 (特集 最強の武器「統計学」 : 宝くじの当選からビッグデータの予測まで) -- (統計の基礎知識)

    樋口 知之

    週刊ダイヤモンド   101 ( 13 )   50 - 51   2013.3

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  • Data Assimilation : Bayesian Inference on Probability Distribution Functions of Model Parameters

    NAGAO Hiromichi, HIGUCHI Tomoyuki

    Journal of the Japan Society of Mechanical Engineers   116 ( 1131 )   89 - 92   2013.2

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  • A dating method for Dome Fuji Ice Core using Sequential Data Assimilation

    SUZUKI KAZUE, KAWAMURA KENJI, NAKANO SHIN'YA, PARRENIN FREDRIC, ABE-OUCHI AYAKO, SAITO FUYUKI, HIGUCHI TOMOYUKI

    極域科学シンポジウム講演予稿集(CD-ROM)   4th   ROMBUNNO.IC,SUZUKIKAZUE,1   2013

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  • データ同化によるオンラインセンシングの高度化

    樋口 知之, 中村 和幸

    計測自動制御学会誌   51巻 ( 9号 )   800 - 807   2012.9

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  • インフルエンザ介入政策における集団免疫を高めるワクチン接種対象群の選択

    斎藤正也, 樋口知之, 井元清哉, 山口類, 坪倉正治, 上昌広, 中田はる佳, 宮野悟, 佐藤弘樹

    統計関連学会連合大会講演報告集   2012   280   2012.9

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  • 南極内陸調査ルート上の年間涵養量と大気輸送の関係

    鈴木香寿恵, 本山秀明, 山内恭, 川村賢二, 樋口知之

    日本気象学会大会講演予稿集   101 ( 101 )   344 - 344   2012.4

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  • Adaptive Simulation of Turbulence Flow by using Data Assimilation

    加藤 博司, 大林 茂, 橋本 敦, 吉澤徴, 上野玄太, 樋口知之

    Journal of Japan Society of Fluid Mechanics   31 ( 2 )   165 - 173   2012.4

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    Other Link: https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=377136

  • EGF receptor tyrosine kinase defines critical prognostic genes of stage IA lung adenocarcinoma

    Asuka Nakata, Mai Yamauchi, Rui Yamaguchi, Takashi Kohno, Masao Nagasaki, Teppei Shimamura, Seiya Imoto, Ayumu Saito, Kazuko Ueno, Yousuke Hatanaka, Ryo Yoshida, Tomoyuki Higuchi, Masaharu Nomura, David G. Beer, Jun Yokota, Satoru Miyano, Noriko Gotoh

    CANCER RESEARCH   72   2012.4

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    DOI: 10.1158/1538-7445.AM2012-LB-99

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  • 菅平微気圧変動とその初期解析 Reviewed

    長尾大道, 富澤一郎, 家森俊彦, 金尾政紀, 徳永旭将, 樋口知之

    月刊地球   34 ( 10 )   580 - 584   2012

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  • 不確実性と予測 : 受益者・生活者の視点と目線にたつシミュレーション研究へ (特集 シミュレーションの数理) -- (気象・自然災害に関するシミュレーション編)

    樋口 知之

    数学セミナー   50 ( 12 )   8 - 12   2011.12

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  • Real and virtual world integration by data assimilation : Online information fusion between big data, database, and computation

    HIGUCHI Tomoyuki

    Technical report of IEICE. PRMU   111 ( 222 )   3 - 3   2011.9

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  • Creating high quality animation of 3D characters via kernel k-means

    HIROSE Kei, HIGUCHI Tomoyuki

    110 ( 476 )   23 - 28   2011.3

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    We propose a new system which enables us to generate a high quality animation of 3D characters via Motion Capture (MoCap) Data. The MoCap Data allows us to create an animation which resembles the motion in a video recording. In some cases of artistic animation, however, the motion capture actor/actress and the 3D character facial animation shows different expressions. The proposed procedure enables us to edit the facial expressions flexibly to generate an artistic animation, while making good use of the original facial motion capture data.

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  • Timing relation between positive bay onsets, Pi 2 onsets, auroral initial brightenings and auroral breakups

    TOKUNAGA Terumasa, NAKAMURA Kazuyuki, HIGUCHI Tomoyuki, UOZUMI Teiji, YOSHIKAWA Akimasa, MORIOKA Akira, YUMOTO Kiyohumi, YUMOTO Kiyohumi

    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)   130th   2011

  • 変化点検出を応用した時系列データからの突発現象の前兆検出アルゴリズム

    徳永 旭将, 池田 大輔, 中村 和幸, 樋口 知之, 吉川 顕正, 魚住 禎司, 藤本 晶子, 森岡 昭, 湯元 清文, CpmnGroup

    研究報告数理モデル化と問題解決(MPS)   2010 ( 14 )   1 - 6   2010.12

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    一般に,前兆現象は突発現象にそのものに比べて非常に目立ちにくく,その開始時刻は曖昧である.従来よく用いられてきた変化点検出法を適用した場合,このような微小で緩慢な変化は見逃されやすい.Tokunaga et al.1) では,Ide and Inoue2) の提案した特異スペクトル分析を応用した変化点検出法 (SST) を,多次元データを用いたアルゴリズム (MSST) へと拡張することで,鋭敏に前兆現象の開始時刻を推定出来ることを示した.MSST は,緩慢な変化も検出できる鋭敏な手法であるが,実データへの適用では誤検出が問題になる.本稿では,突発現象の大まかな開始時刻を予め検出し,さらに検出された時刻の前後で前兆現象の開始時刻と終了時刻を個別に探索することで,誤検出を劇的に減少させることができることを示す.

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  • 座談会 いまモデル化が求められる理由—特集 モデル化 変化する現実認識

    合原 一幸, 今井 浩, 樋口 知之

    科学   80 ( 12 )   1176 - 1186   2010.12

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    Other Link: http://id.ndl.go.jp/bib/10887823

  • W201 Data Assimilation : Synthesis Tool for Fusion of Heterogeneous Information Sources

    Higuchi Tomoyuki

    Fluids engineering conference ...   2010   607 - 608   2010.10

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    Data Assimilation (DA) is a technique for a synthesis of information from a dynamic numerical model and observation data. In statistical methodology, DA can be formulated in the generalized state space model. We briefly explain a recent advancement in the ensemble-based sequential DA (EnSDA), and discuss on how EnSDA is employed in combining CFD and EFD.

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  • データ同化による都市間移動を考慮したインフルエンザA(H1N1)パンデミックシミュレーション

    斎藤正也, 井元清哉, 山口類, 佐藤弘樹, 中田はる佳, 上昌広, 宮野悟, 樋口知之

    統計関連学会連合大会講演報告集   2010   106   2010.9

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  • Critical prognostic genes for stage I lung cancer are identified from normal growth factor-regulated gene network by overcoming cancer heterogeneity

    Noriko Gotoh, Mai Yamauchi, Rui Yamauchi, Masao Nagasaki, Teppei Shimamura, Seiya Imoto, Ayumu Saito, Kazuko Ueno, Yousuke Hatanaka, Ryo Yoshida, Tomoyuki Higuchi, Masaharu Nomura, Takashi Kohno, Jun Yokota, David G. Beer, Satoru Miyano

    CANCER RESEARCH   70   2010.4

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    DOI: 10.1158/1538-7445.AM10-LB-132

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  • 高次元状態空間に対する粒子フィルタIEPFの提案

    グエン ベトフォン, 鷲尾 隆, 樋口 知之

    全国大会講演論文集   72   249 - 250   2010.3

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  • STPデータからの異常検出法の開発: Substorm precursor検出への応用—Development of a method for detecting anomalies from STP data: Application to detecting substorm precursor

    徳永, 旭将, 中村, 和幸, 樋口, 知之, 吉川, 顕正, 魚住, 禎司, 池田, 大輔, 藤本, 晶子, 森岡, 昭, 湯元, 清文, Tokunaga, Terumasa, Nakamura, Kazuyuki, Higuchi, Tomoyuki, Yoshikawa, Akimasa, Uozumi, Teiji, Ikeda, Daisuke, Fujimoto, Akiko, Morioka, Akira, Yumoto, Kiyofumi

    宇宙航空研究開発機構特別資料: 第6回「宇宙環境シンポジウム」講演論文集 = JAXA Special Publication: Proceedings of the 6th Spacecraft Enivironment Symposium   JAXA-SP-09-006   260 - 265   2010.2

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    第6回宇宙環境シンポジウム (2009年2月29日-30日. 北九州国際会議場)
    6th Spacecraft Enivironment Symposium (February 29-30, 2009. Kitakyushu International Conference Center)
    形態: カラー図版あり
    Physical characteristics: Original contains color illustrations
    資料番号: AA0064542030
    レポート番号: JAXA-SP-09-006

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  • STPデータからの異常検出法の開発~substorm precursor検出への応用

    徳永旭将, 中村和幸, 樋口知之, 吉川顕正, 魚住禎司, 池田大輔, 藤本晶子, 森岡昭, 湯元清文

    宇宙航空研究開発機構特別資料 JAXA-SP-   ( 09-006 )   260 - 265   2010.2

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  • A parameter estimation for Biological pathway model using GPGPU

    HAYASHI KEISUKE, SAITO MASAYA, YOSHIDA RYO, HIGUCHI TOMOYUKI

    2009 ( 19 )   1 - 3   2009.12

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  • Graphical modeling of intercellular biochemical pathways and statistical inferences(<Special Section>Bioinformatics)

    Yoshida Ryo, Higuchi Tomoyuki

    Journal of the Japan Statistical Society Japanese issue   38 ( 2 )   213 - 236   2009.3

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    States of living cells are controlled by a series of biochemical reactions, e.g. binding and phosphorylation of protein molecules, gene expressions intermediated by transcription factors. In systems biology, mathematical modeling and simulation, based on biochemical rate equations, have proved to be an efficient approach for unraveling complex cellular mechanisms of the biological pathways. The aim of this paper is to show some recent developments of statistical technologies for the data-driven construction of in silico biological pathways, which are referred to as Genomic Data Assimilation (GDA). The proposed method involves the following protocols: (1) Knowledge-based model construction of biological pathway based on rate equations, (2) Estimation of model parameters (e.g. kinetic rate constants), (3) Statistical evaluation and comparison of hypothetical models, (4) Remodeling where needed. After showing a brief review, we point out some issues to be addressed from statistical points of view. We also report our recent developments in this area.

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  • An evolutionary algorithm optimizes boundary bathymetric condition in an ocean tide model

    INAZU Daisuke, HIGUCHI Tomoyuki, NAKAMURA Kazuyuki

    IPSJ SIG Notes   2009 ( 19 )   29 - 32   2009.2

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    An evolutionary algorithm (EA) is applied to a regional ocean tide model to optimize a boundary condition and a physical parameter in the model. The bathymetry is one of the boundary conditions in ocean models and is frequently given by global sea depth data based on estimation derived from the satellite gravity observation. Accuracy of the satellite-derived depth data is often insufficient for accurate ocean tide simulations. We apply the EA to modify the mean depth in specific regions in the Alaska Panhandle, U.S. The mean depth in those regions is optimized to be close to the multibeam-derived depth data which is generally accurate further more than the satellite-derived data but its spatial coverage is sparse. Also, a region with large errors of the satellite-derived data is successfully found through the optimization. The EA has a prospect of correction of erroneous boundary conditions for accurate ocean modeling.

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    Other Link: http://id.nii.ac.jp/1001/00061902/

  • 地上観測されたPi2型地磁気脈動のグローバルな波動特性解析のための周波数領域独立成分分析の応用

    徳永旭将, 吉川顕正, 魚住禎司, 樋口知之, 中村和幸, 湯元清文

    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)   126th   ROMBUNNO.B006-P018   2009

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  • Recent Advances and Applications on Bayesian Theory [II] : Sequential Bayesian Estimation and Data Assimilation

    NAKAMURA Kazuyuki, HIGUCHI Tomoyuki

    The Journal of the Institute of Electronics, Information and Communication Engineers   92 ( 12 )   1062 - 1067   2009

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  • A detection of substorm precursors on geomagnetic data at auroral latitudes by SSA-based change-point analysis

    TOKUNAGA Terumasa, NAKAMURA Kazuyuki, HIGUCHI Tomoyuki, YOSHIKAWA Akimasa, UOZUMI Teiji, MORIOKA Akira, YUMOTO Kiyohumi, YUMOTO Kiyohumi

    地球電磁気・地球惑星圏学会総会及び講演会予稿集(CD-ROM)   126th   2009

  • On the Special Issue "Data Mining and Statistical Mathematics"

    56 ( 2 )   167 - 168   2008.12

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  • Preface: Featured section on data-mining and statistical science

    Tomoyuki Higuchi, Takashi Washio

    ANNALS OF THE INSTITUTE OF STATISTICAL MATHEMATICS   60 ( 4 )   697 - 698   2008.12

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    DOI: 10.1007/s10463-008-0208-y

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  • 動的ネットワーク構造探索の計算イニシアティブ バイオマーカー・分子標的探索のための動的ネットワークを予測する計算科学的方法の開発

    井元 清哉, 山口 類, 島村 徹平, 玉田 嘉紀, 長崎 正朗, 斉藤 あゆむ, 植野 和子, 畑中 洋亮, 吉田 亮, 樋口 知之, 山内 麻衣, 後藤 典子, 宮野 悟

    日本生化学会大会・日本分子生物学会年会合同大会講演要旨集   81回・31回   4S8 - 4   2008.11

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  • 統計的モデリングとしてのデータ同化と工学シミュレーションへの応用(特別セッション 複雑系データの分析)

    中村 和幸, 樋口 知之

    日本行動計量学会大会発表論文抄録集   36   105 - 106   2008.9

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  • ペトリネットによる転写制御ネットワークのモデリングと統計的推測

    吉田 亮, 長崎 正郎, 山口 類, 井元 清哉, 宮野 悟, 樋口 知之

    情報処理学会研究報告. BIO, バイオ情報学   13   9 - 11   2008.6

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  • Graphical modeling and statistical inferences of transcription regulatory networks using hybrid functional Petri net

    YOSHIDA Ryo, NAGASAKI Masao, YAMAGUCHI Rui, IMOTO Seiya, MIYANO Satoru, HIGUCHI Tomoyuki

    IPSJ SIG technical reports   2008 ( 58 )   9 - 11   2008.6

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    Building in silico simulation models of genetic regulatory networks provides a rigorous tool for unraveling complex machinery of biological pathways. To proceed to in silico simulations, it is an essential first step to find the effective values of kinetic rate constants, which are difficult to measure directly from in vivo and in vitro experiments. The aim of this research is to present a new statistical technology, called Genomic Data Assimilation, for the data-driven construction of in silico simulation models.

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  • ハリウッド映画に見る近未来の情報技術 : パーソナライゼーション技術

    樋口知之

    知能と情報 : 日本知能情報ファジィ学会誌 : journal of Japan Society for Fuzzy Theory and Intelligent Informatics   20 ( 2 )   153 - 153   2008.4

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  • D-12-105 Acoustic Spectrum Classification by Divergence-based Kernel Clssifiers

    Ishigaki Tsukasa, Higuchi Tomoyuki

    Proceedings of the IEICE General Conference   2008 ( 2 )   236 - 236   2008.3

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  • An analysis of POS data using dynamic market response models

    Journal of marketing science   15 ( 1 )   1 - 26   2008.3

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  • 全体モデルから局所モデルへ--状態空間モデルとシミュレーション (特集 統計科学のすすめ(その2))

    樋口 知之

    数学セミナー   46 ( 11 )   30 - 36   2007.11

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  • 新しい科学の「かたち」(特集:赤池統計学の世界 / Part3 赤池弘次博士に聞く)

    樋口 知之, Tomoyuki HIGUCHI, ヒグチ トモユキ

    総研大ジャーナル = Sokendai journal   ( 12 )   25 - 25   2007.9

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  • データ同化 : 複雑システム理解の新しい道具(セッションS-11(MK203) 特別セッション 複雑系データの解析)

    樋口知之, データ同化チーム

    日本行動計量学会大会発表論文抄録集   35   217 - 218   2007.9

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  • On the Special Issue "Prediction and Knowledge Discovery"

    54 ( 2 )   209 - 210   2006.12

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  • Mining Closed Frequent DAGs from Gene Network Data with Dryade

    20   1 - 3   2006

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  • DryadeによるGene Network DAGデータからの飽和頻出木マイニング

    ターミエ アレックサンドル, 鷲尾 隆, 樋口 知之, 玉田 嘉紀, 井元 清哉, 大原 剛三, 元田 浩

    人工知能学会全国大会論文集   6 ( 0 )   7 - 7   2006

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    本研究ではバイオインフォマティクスのデータから飽和頻出木をマイニングすることを試みる。対象データの構造はDAGなので、我々のツリーマイニングアルゴリズムDryadeをDAGに適用可能なように改良した。実験でこの効果を確かめる。

    DOI: 10.11517/pjsai.JSAI06.0.7.0

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  • Automatic Online Detection and Classification of Occuring Disaster with a Multivariable Detecting Sensor for Home Security System

    WATANABE Kajiro, Tsukasa Ishigaki, Tomoyuki,Higuchi

    I-89D ( 11 )   2404 - 2412   2006

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  • State space model approach to analyse cDNA microarray time course data of yeast

    YAMAGUCHI Rui, HIGUCHI Tomoyuki

    IPSJ SIG technical reports   2005 ( 128 )   67 - 73   2005.12

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    In this study, we apply a state space model to time course gene expression data of yeast (Saccharomyces cerevisiae). We estimate parameters characterizing the system by using EM algorithm and determine the optimal dimension of hidden state variable by an information criterion. Then we compare the result with those in other papers using the same model and the same data but with different methods to estimate the parameters and to determine the internal dimension.

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  • ジオスペース探査衛星ERG(Energization and Radiation in Geospace)について

    塩川和夫, 関華奈子, 三好由純, 家田章正, 西谷望, 品川裕之, 寺田直樹, 小野高幸, 飯島雅英, 熊本篤志, 長妻努, 小原隆博, 菊池崇, 島津浩哲, 高島健, 浅村和史, 笠羽康正, 松岡彩子, 齋藤義文, 齋藤宏文, 五家建夫, 平原聖文, 利根川豊, 遠山文雄, 能勢正仁, 家森俊彦, 大村善治, 笠原禎也, 湯元清文, 河野英昭, 吉川顕正, 田中高史, 海老原祐輔, 行松彰, 佐藤夏雄, 石坂圭吾, 三宅壮聡, 岡田敏美, 渡辺重十, 樋口知之

    宇宙航空研究開発機構特別資料 JAXA-SP-   ( 04-010 )   2005

  • Identification of time-dependent and -independent factors based on decomposition of daily sales of a restaurant

    HIGUCHI Tomoyuki

    IEICE technical report. Neurocomputing   104 ( 349 )   39 - 43   2004.10

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    Daily sales of a catering establishment is affected by several factors: A day of the week, national holidays, weather, events taken place near the site, etc. Therefore, it is no doubt beneficial to make a model decomposing a time series of the sales into such factors. Then the model allows us to predict the future sales with a good accuracy in order to plan various levels of management strategies such as purchase, staff assignments, new store openings, etc. In this study, we have proposed a prediction method for daily sales of a catering establishment based on a state space model framework in which an optimal model chosen by an information criterion; we have applied it to daily sales data for two years of a restaurant which is adjacent to a large-scale convention center and office buildings.

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  • Decomposition of daily sales of a restaurant based on the state space modeling

    20   549 - 554   2004.6

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  • Ionospheric conductivity dependence of dayside region-0, 1, and 2 field-aligned current systems: statistical study with DMSP-F7

    K Haraguchi, H Kawano, K Yumoto, S Ohtani, T Higuchi, G Ueno

    ANNALES GEOPHYSICAE   22 ( 8 )   2775 - 2783   2004

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    The present study statistically examines the dependence of the intensities of dayside (MLT = 8-12 h) large-scale field-aligned currents (FACs) on the ionospheric conductance using the summary data of DMSP-F7 constructed by the procedure of Higuchi and Ohtani (2000). We have found that, in the dayside region, R1 and R0 have a higher correlation between ionospheric conductivity and FAC intensity than R2, suggesting that R0 and R1 are driven by a more voltage-like source than R2. This result is consistent with the idea that R1 and R0 are driven by the interaction between the solar wind and the open magnetospheric magnetic field. We have also found that dayside FAC intensities are latitudinally well balanced when they have a three sheet structure (R0, R1 and R2); on the other hand, for a two sheet structure (R1 and R2), the intensity of R1 is larger than that of R2, so that the net current has the polarity of R1.

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  • 公開講演会要旨(統計数理研究所研究活動) データに潜む知を引き出すモデルと予測

    樋口 知之

    統計数理   52 ( 1 )   189 - 195   2004

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  • Adjustment of Non-Uniform Sampling Locations in Spatial Datasets with Dynamic Programming and Non-Linear Filtering

    Masako Kamiyama, Tomoyuki Higuchi

    IEEE Signal Processing Magazine   47 - 56   2004

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  • 観測されない非価格プロモーション実施の有無のPOSデータからの統計的推測法

    佐藤 忠彦, 樋口 知之, 北川 源四郎

    日本統計学会講演報告集   71   335 - 336   2003.9

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  • 遺伝子発現データと生物学的知識からの遺伝子ネットワークの推定

    井元 清哉, 樋口 知之, 後藤 多嘉緒, 田代 康介, 久原 哲, 宮野 悟

    日本統計学会講演報告集   71   143 - 144   2003.9

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  • ベイジアンネットワークと測定ノイズロバストな遺伝子ネットワークの推定

    樋口 知之, 井元 清哉, 金 順暎, 宮野 悟

    日本統計学会講演報告集   71   139 - 140   2003.9

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  • DNAアレイデータ概説

    井元 清哉, 樋口 知之

    日本統計学会講演報告集   71   131 - 132   2003.9

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  • 測定誤差の特性を考慮したサンプリング間不均一性の補正

    神山 雅子, 樋口 知之

    日本統計学会講演報告集   71   509 - 510   2003.9

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  • 状態空間モデルによる飲食店売上げ予測

    山口 類, 土屋 映子, 樋口 知之

    日本統計学会講演報告集   71   331 - 332   2003.9

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  • 観測不能領域を含むデータに対する混合分布モデルの適用

    中村 永友, 上野 玄太, 樋口 知之, 小西 貞則

    日本統計学会講演報告集   71   503 - 504   2003.9

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  • Error Evaluation of Planetary Atmospheric Motion Vectors by Statistical Presumption Technique

    Murachi Tetsunori, Imamura Takeshi, Higuchi Tomoyuki

    125   1 - 25   2003.9

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    The purpose of this study is to establish the error evaluation of Atmospheric Motion Vectors (AMVs) which reflects influence of the image spatial resolution and the change of cloud shape that are the essential primary factor of AMVs' error. In past meteorological researches AMVs' error is defined as the standard deviation of neighboring AMVs. In this definition, however, the AMVs' error is larger than the target physical phenomenon. In this study, by statistical presumption technique, which presumes the detail information from the limited information, we evaluate the AMVs' error which reflects influence of the image spatial resolution and the change of cloud shape. In order to verify this method, we make simple and fractal cloud patterns, and calculate the AMVs and the error estimated by statistical presumption technique and the error by past error evaluation. The result is that the error by statistical presumption technique is as small as a quarter of the error by past error evaluation. In this study, by statistical presumption technique the error evaluation of AMVs that reflects influence of the image spatial resolution and the change of cloud shape is established.

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    Other Link: http://repository.tksc.jaxa.jp/pl/dr/IS0200054000

  • C-5 観測されない非価格プロモーション実施の有無のPOSデータからの統計的推測法(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    佐藤 忠彦, 樋口 知之, 北川 源四郎

    日本統計学会誌   33 ( 3 )   406 - 406   2003

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    Other Link: http://id.nii.ac.jp/1141/00024500/

  • 地磁気ジャークから推定される下部マントル電気伝導度不均一性 (電場観測および大規模電気伝導度構造)

    長尾 大道, 家森 俊彦, 樋口 知之

    Conductivity anomaly研究会論文集   82 - 89   2003

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  • D-3 観測不能領域を含むデータに対する混合分布モデルの適用(統計モデル)(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    中村 永友, 上野 玄太, 樋口 知之, 小西 貞則

    日本統計学会誌   33 ( 3 )   418 - 418   2003

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    Other Link: http://id.nii.ac.jp/1141/00024580/

  • D-6 測定誤差の特性を考慮したサンプリング間不均一性の補正(統計モデル)(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    神山 雅子, 樋口 知之

    日本統計学会誌   33 ( 3 )   418 - 418   2003

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    Other Link: http://id.nii.ac.jp/1141/00024583/

  • B-1 DNAアレイデータ概説(企画セッション:DNAアレイデータ解析に関する統計的諸問題)(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    井元 清哉, 樋口 知之

    日本統計学会誌   33 ( 3 )   392 - 392   2003

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    Other Link: http://id.nii.ac.jp/1141/00024405/

  • B-7 遺伝子発現データと生物学的知識からの遺伝子ネットワークの推定(企画セッション:DNAアレイデータ解析に関する統計的諸問題)(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    井元 清哉, 樋口 知之, 後藤 多嘉緒, 田代 康介, 久原 哲, 宮野 悟

    日本統計学会誌   33 ( 3 )   393 - 393   2003

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    Other Link: http://id.nii.ac.jp/1141/00024411/

  • B-5 ベイジアンネットワークと測定ノイズロバストな遺伝子ネットワークの推定(企画セッション:DNAアレイデータ解析に関する統計的諸問題)(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    樋口 知之, 元 清哉, 金 順暎, 宮野 悟

    日本統計学会誌   33 ( 3 )   393 - 393   2003

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  • C-3 状態空間モデルによる飲食店売上げ予測(2003年度統計関連学会連合大会記録(日本統計学会第71回大会))

    山口 類, 土屋 映子, 樋口 知之

    日本統計学会誌   33 ( 3 )   406 - 406   2003

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  • Knowledge Discovery by Model-based Prediction Approach

    HIGUCHI Tomoyuki

    Journal of the Japan Society of Mechanical Engineers   105 ( 1009 )   800 - 801   2002.12

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  • モンテカルロ混合カルマンフィルタと平滑化アルゴリズム

    樋口 知之

    日本統計学会講演報告集   70   317 - 318   2002.9

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  • プラズマ速度分布データへの正規混合分布モデルの応用

    上野 玄太, 中村 永友, 樋口 知之

    日本統計学会講演報告集   70   321 - 322   2002.9

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  • マルコフ切り換え回帰モデルのよるPOSデータの解析

    佐藤 忠彦, 樋口 知之, 北川 源四郎

    日本統計学会講演報告集   70   174 - 175   2002.9

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  • 動的計画法と非線形フィルタリング : 鉄道線路形状データの前処理

    神山 雅子, 樋口 知之

    日本統計学会講演報告集   70   319 - 320   2002.9

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  • 混合分布モデルによるプラズマ粒子速度データの分析

    中村 永友, 上野 玄太, 樋口 知之

    日本統計学会講演報告集   70   323 - 324   2002.9

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  • Pi2 onset time determination with information criterion

    T Higuchi, SI Ohtani, T Uozumi, K Yumoto

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   107 ( A7 )   2002.7

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    [1] The present study proposes a new method to identify ground Pi2 onsets. The Pi2 wave is usually examined by applying a linear band-pass filter or something equivalent, such as wavelet convolution, to ground magnetometer data, and its onset is determined based on the amplitude of the extracted wave component. The proposed method is distinguished from such conventional methods in terms of the following points. First the proposed method does not filter or smooth data, rather it analyzes the original data. Second the proposed method determines the Pi2 onset so that the intervals before and after the onset can be optimally described by different time series models. The optimal partition is determined by minimizing the Akaike information criterion (AIC). The time series models adopted are general enough to apply to any nonstationary time series irrespective of its waveform, frequency, amplitude, and signal-to-noise ratio. As a result, the proposed procedure is free from the choice of a threshold and is therefore objective. The procedure is applied to simulation data, and it is confirmed that the procedure can determine the onset with the precision of the data's time resolution. An application to magnetic field data from 210degrees magnetic meridian (MM) stations suggests that our procedure can be used for examining the latitudinal and longitudinal dependence of the onset time. The proposed procedure is expected to be useful for examining issues that have been difficult to address with conventional methods because of the precision required for determining Pi2 onset.

    DOI: 10.1029/2001JA003505

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  • A-4 プラズマ粒子速度データの混合分布モデルによる分析

    中村 永友, 上野 玄太, 樋口 知之

    日本統計学会誌   32 ( 3 )   370 - 370   2002

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    Other Link: http://id.nii.ac.jp/1141/00024248/

  • B-4 マルコフ切り換え回帰モデルによるPOSデータの解析

    佐藤 忠彦, 樋口 知之, 北川 源四郎

    日本統計学会誌   32 ( 3 )   361 - 361   2002

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    Other Link: http://id.nii.ac.jp/1141/00024196/

  • A-2 動的計画法と非線形フィルタリング : 鉄道線路形状データの前処理

    神山 雅子, 樋口 知之

    日本統計学会誌   32 ( 3 )   369 - 369   2002

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  • A-3 プラズマ速度分布データへの正規混合分布モデルの応用

    上野 玄太, 中村 永友, 樋口 知之

    日本統計学会誌   32 ( 3 )   370 - 370   2002

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  • 自己調節・進化する時系列モデル

    樋口 知之

    日本統計学会講演報告集   69   243 - 244   2001.9

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  • 等間隔サンプリングで計測設計された空間系列データ中の不均一サンプリング区間の同定

    神山 雅子, 樋口 知之

    日本統計学会講演報告集   69   339 - 340   2001.9

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  • KNOWLEDGE DISCOVERY FROM LARGE-SCALE GEOPHYSICAL DATASET BASED ON A STATISTICAL MODELING

    Higuchi Tomoyuki

    Proceedings of the Society Conference of IEICE   2001   378 - 379   2001.8

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  • Four-sheet structures of dayside field-aligned currents: Statistical study (vol 105, pg 25, 2000)

    S Ohtani, T Higuchi

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   106 ( A5 )   8489 - 8489   2001.5

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  • Special issue on nonlinear non-gaussian models and related filtering methods

    G Kitagawa, T Higuchi

    ANNALS OF THE INSTITUTE OF STATISTICAL MATHEMATICS   53 ( 1 )   III - III   2001.3

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    Web of Science

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  • A-4 等間隔サンプリングで計測設計された空間系列データ中の不均一サンプリング区間の同定(時系列解析・制御理論(2))(日本統計学会第69回大会記録)

    神山 雅子, 樋口 知之

    日本統計学会誌   31 ( 3 )   410 - 410   2001

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    Other Link: http://id.nii.ac.jp/1141/00024088/

  • C-4 準周期的な波動現象観測開始時刻の精密推定(日本統計学会第68回大会記録 : 時系列解析・制御理論 (3))

    樋口知之

    日本統計学会誌   30 ( 3 )   344 - 344   2000.12

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  • 準周期的な波動現象観測開始時刻の精密推定

    樋口 知之

    日本統計学会講演報告集   68   92 - 93   2000.7

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  • Automatic Identification of the Large Scale Field Aligned Current Systems as an Example of Knowledge Discovery from the Large Database

    47 ( 2 )   291 - 306   1999.12

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  • 自動平滑化法によるGPS日データの平均的時空間構造の抽出

    樋口 知之

    人工知能基礎論研究会   ( 37 )   119 - 122   1999.7

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  • 低高度周回人工衛星によって観測された空間系列デ-タの自動特徴抽出

    樋口 知之

    人工知能基礎論研究会   ( 35 )   71 - 74   1998.12

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  • 予測とモデル (<特集>モデルとモデリング モデル論の構築をめざして)

    北川 源四郎, 樋口 知之

    数理科学   36 ( 9 )   11 - 18   1998.9

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  • 可変節点 Linear Spline を用いた時系列データの自動構造抽出

    樋口 知之

    日本統計学会講演報告集   66   162 - 162   1998.7

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  • 離散時系列データの季節調整法

    樋口 知之

    日本統計学会講演報告集   66   204 - 204   1998.7

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  • A Seasonal Adjustment Designed to Deal with the Time Series Observed in the Natural Phenomena

    45 ( 2 )   319 - 328   1997.12

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  • Genetic Algorithm and Monte Carlo Filter

    44 ( 1 )   19 - 30   1996.6

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  • IMPROVEMENTS ON THE ESTIMATION OF THE LOG - LIKELIHOOD OBTAINED THROUGH THE MONTE CARLO FILTER

    Higuchi Tomoyuki

    IPSJ SIG Notes   94 ( 108 )   7 - 14   1994.12

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    The algorithm with a name of "Monte Carlo Filter" (MCF) has been presented for the non-Gaussian state space model. In this study, we investigate the connections between the Genetic Algorithm (GA) and MCF. One of the objectives of this paper is to cast the GA into the Bayesian framework by its interpretation from a viewpoint of the MCF. Several ideas to improve an original MCF algorithm are shown based on a numerical experience to estimate the log-likelihood more accurately.

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  • A Method to Separate the Spin Synchronized Signals Using a Bayesian Approach

    41 ( 2 )   115 - 130   1993.12

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  • An Interpretation of Auto-regression (AR) Model by Using a Linear Algebra

    38 ( 1 )   31 - 45   1990.6

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  • Fractal Analysis of Time Series

    37 ( 2 )   209 - 233   1989.12

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  • Adjustment of Sampling Locations in Rail-Geometry Datasets: using Dynamic Programming and Non-Linear Filtering

    Masako Kamiyama, Tomoyuki Higuchi

    Systems and Computers in Japan   J87-D-II ( 6 )   1199 - 1207  

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Presentations

  • 注意機構を用いた準周期信号のオンライン周期推定と異常値同定の同時実現 Invited

    石曽根毅, 樋口知之, 大草孝介, 中村和幸

    Prof. Toshinari Kamakura’s Retirement Commemoration Symposium  ( 宜野湾市、沖縄 )   2024.3 

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  • 人流ビッグデータを内包する感染症モデルのデータ同化による新型コロナウイルス感染動態の解析

    荒井智史, 大野航太, 樋口知之

    日本応用数理学会 若手の会 第9回学生研究発表会  ( 長岡市 )   2024.3  日本応用数理学会

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    Language:Japanese   Presentation type:Poster presentation   Country:Japan  

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  • Domain Adaptation for Application to Smart Meters of Electricity Usage in Each Household Invited International conference

    Hisashi Oshima, Tomoyuki Higuchi, Tsuyoshi Ishizone

    Statistical Computing And Robust Inference For High Dimensional Data(SCRI2023)  ( Taipei, Taiwan )   2023.12 

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    Event date: 2023.12    

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  • 生成AIの登場により データサイエンスで学ぶことは 変わるのか? Invited

    樋口知之

    長崎大学 情報データ科学部 特別講演会  ( 長崎 )   2023.11  長崎大学情報データ科学部

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  • ChatGPT: 連想ゲームつぶやきマシンだけどものすごい性能と 私たちはどうつきあうか? Invited

    樋口 知之

    日本経営工学会(JIMA)関東支部主催 2023年度 第1回講演会  ( 東京都文京区 )   2023.6  日本経営工学会(JIMA)関東支部

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  • AIとDXが促す組織構造と企業文化の変化 Invited

    樋口知之

    公開講座 未来展望セミナー2022(第七回)  ( 大阪 )   2023.1  大阪成蹊大学

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  • Occupancy Detection for General Households by Bidirectional LSTM with Attention International conference

    Hisashi Oshima, Tsuyoshi Ishizone, Kazuyuki Nakamura, Tomoyuki Higuchi

    48th Annual Conference of the IEEE Industrial Electronics Society (IECON 2022)  ( Brussels )   2022.10 

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    Language:English   Presentation type:Oral presentation (general)   Country:Belgium  

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  • An Online System of Detecting Anomalies and Estimating Cycle Times for Production Lines International conference

    Tsuyoshi Ishizone, Tomoyuki Higuchi, Kosuke Okusa, Kazuyuki Nakamura

    48th Annual Conference of the IEEE Industrial Electronics Society Conference(IECON 2022)  ( Brussels )   2022.10 

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    Language:English   Presentation type:Oral presentation (general)   Country:Belgium  

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  • いよいよ動き出した地震ビッグデータ解析の中核をなす機械学習技術 Invited

    樋口 知之

    2022年度統計関連学会連合大会  ( 東京 オンライン ハイブリッド開催 )   2022.9  統計関連学会連合 応用統計学会 日本計算機統計学会 日本計量生物学会 日本行動計量学会 日本統計学会 日本分類学会

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  • 帰納と演繹の融合: データ同化と深層学習 Invited

    樋口 知之

    応⽤統計学フロンティアセミナー  ( 東京 オンライン ハイブリッド開催 )   2022.1  応用統計学会

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  • データサイエンスとは何か?統計学、AIとの違いと共通点を理解することで深まる総合教育の理想像 Invited

    樋口知之

    宮崎大学数理・データサイエンス・AI教育強化事業 令和3年度シンポジウム「宮崎大学におけるデータサイエンス教育のこれまでとこれから」  ( オンライン )   2021.12  宮崎大学

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  • Ensemble Kalman Filter を活用した時系列モデルの変分推論フレームワーク

    石曽根 毅, 樋口 知之, 中村 和幸

    2021年度統計関連学会連合大会  ( 長崎 )   2021.9  統計関連学会連合 応用統計学会 日本計算機統計学会 日本計量生物学会 日本行動計量学会 日本統計学会 日本分類学会

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  • 隣接領域との競争と共創が促す統計学の力強い発展 Invited

    樋口 知之

    2021年度統計関連学会連合大会  ( オンライン )   2021.9  統計関連学会連合 応用統計学会 日本計算機統計学会 日本計量生物学会 日本行動計量学会 日本統計学会 日本分類学会

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  • 変分推論・非線形フィルタリングを駆使した時系列データの潜在モデルの推論・予測

    石曽 根毅, 樋口 知之, 中村 和幸

    情報処理学会 第83回全国大会  ( 大阪大学 豊中キャンパス=>オンライン開催 )   2021.3  一般社団法人情報処理学会

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  • 一般家庭用電力スマートメーターへの適用を目的とする世帯の在宅推定手法の開発

    大島 悠, 石曽根 毅, 樋口 知之

    第15回日本統計学会春季集会  ( オンライン )   2021.3  日本統計学会 統計数理研究所

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  • 機械学習の基礎 Invited

    樋口 知之

    機械学習×熱・流体工学の最先端  ( オンライン )   2021.3  日本機械学会

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  • 知能革命 Invited

    樋口知之

    日経イベント&セミナー 大学の約束2020オンラインカンファレンス  ( 東京 オンライン )   2020.12  日本経済新聞社

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  • Latent Trajectory Estimation with Ensemble Kalman Filter and Neural Network

    石曽根 毅, 樋口 知之, 中村 和幸

    数学数理科学専攻若手研究者のための 研究交流会 異 分 野・異 業 種 2020  ( オンライン )   2020.10  日本数学会 日本応用数理学会

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  • ビッグデータ環境下の統計学の姿 Invited

    樋口知之

    日本SASユーザー会フォーラム2020  ( オンライン )   2020.10  SASユーザー会世話人会

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  • 汽水型人材育成: 製造業におけるAI/DS人材育成の課題と加速 Invited

    樋口知之

    【統計数理研究所オープンハウス連携イベント】データサイエンスの現在と未来を解剖する!~企業向け産学連携シンポジウム~  ( 立川 オンライン )   2020.10  情報・システム研究機構 統計数理研究所

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  • AI・データサイエンス人材育成の産業界との協働 Invited

    樋口知之

    第11回横幹連合コンファレンス  ( 立川 オンライン )   2020.10  特定非営利活動法人横断型基幹科学技術研究団体連合

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  • 今後の社会とデータサイエンティスト養成:世界の動向と日本 Invited

    樋口知之

    2050技術・マネジメント知の育成研究会(TM研究会) 第 2 回研究交流会  ( 東京 )   2020.7  TM研究会

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    Event date: 2020.7    

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  • データ駆動科学の発展とインパクト Invited

    樋口 知之

    TFC Online Seminar Series 1st Seminar 実験家のためのデータ駆動科学オンラインセミナー  2020.5  東北大学 研究推進・支援機構知の創出センター

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    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech   Country:Japan  

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  • DX化の鍵:データサイエンス・リテラシー Invited

    樋口 知之

    第1回DX特別経営セミナー デジタルトランスフォーメーションが創る未来と戦略 -産官学連携のKOBEモデルの構築-  ( 神戸市 )   2019.12  一般社団法人デジタルトランスフォーメーション研究機構、神戸大学数理・データサイエンスセンター

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  • ベイズモデリングと歩んだ30年 Invited

    樋口 知之

    統計数理研究所 樋口前所長退任記念シンポジウム 「データ駆動型研究を先導するベイズモデリング」 ~ モデリングは人がやるのか、AIが代替するのか ~  ( 東京都千代田区 )   2019.11  情報・システム研究機構 統計数理研究所

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  • データサイエンスが誘うメゾスコピックHPC Invited

    樋口 知之

    科学技術計算分科会 2019年度会合「HPC道 ~われわれの進むべき道は?~」  ( 神戸市 )   2019.10  サイエンティフィック・システム研究会

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  • AIとデータサイエンス:共通の軸と違いを知ることでわかる未来の扉 Invited

    樋口 知之

    数理・データサイエンス教育中部・東海ブロックワークショップ  ( 名古屋 )   2019.9  滋賀大学

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  • データ駆動型推論とシミュレーション計算の融合と将来像 Invited

    樋口 知之

    兵庫県立大学神戸情報科学キャンパスシンポジウム  ( 神戸市 )   2019.9  兵庫県立大学

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  • データサイエンスが育む新たな価値創造 Invited

    樋口 知之

    住友グループ一水会例会  ( 大阪市 )   2019.9  一水会

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  • データ駆動型研究開発のTIPSと組織内での人材育成策 Invited

    樋口 知之

    豊田自動織機-産総研連携研究室主催 アドバンスト・ロジスティクス講演会  ( 産総研臨海副都心センター 江東区 )   2019.8  豊田自動織機-産総研連携研究室

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  • 成熟期にはいったデータ同化計算技術 Invited

    樋口 知之

    日本シミュレーション学会総会  ( 文京区 )   2019.8  日本シミュレーション学会

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  • AI時代におけるモデリング研究の変容と次の一手 Invited

    樋口 知之

    計測自動制御学会オープンライフデータ委員会  ( 東京 )   2019.6 

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  • AIとデータサイエンスが誘う文理融合を超えた学術研究のミライ形 Invited

    樋口 知之

    中央大学理工学部「研究教育 クラスター」1周年記念シンポジウム  ( 東京 )   2019.3 

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  • 人工知能とデータサイエンティストの役回り Invited

    樋口 知之

    公開講座 新潟県立大学 国際産業経済セミナー 「データサイエンスとイノベーション」  ( 新潟 )   2019.3 

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  • AIと統計的モデリングのはざまで~次の世代に期待する事

    樋口 知之

    統合的都市インフラサービスのため の自律的な情報基盤のありかた~ポストAI・スマートシティを見据えて  ( 東京 )   2019.2 

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  • Statistical Machine Learning in the Era of Big Data snd AI Invited International conference

    Tomoyuki HIGUCHI

    Roundtable Discussion on "New Global Era of Digital Economies"~T20Japan Associated Event~  ( Jakarta, Indonesia )   2019.1  ERIA, IDE-JETRO

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  • Weather prediction Review International conference

    Tomoyuki HIGUCHI

    CREST International symposium on big data application  2019.1 

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  • 分野をつなぎ、イノベーションを生み出すデータサイエンスの力 Invited

    樋口 知之

    神戸大学 数理・データサイエンスセンター 1周年記念シンポジウム  ( 神戸市 )   2018.12  国立大学法人神戸大学数理・データサイエンスセンター

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  • 人工知能により激変する職業選択:今、安定な職でも5年後には消滅!? Invited

    樋口 知之

    宮崎県立大宮高等学校「大宮ハローワーク」  2018.9 

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  • 情報モデリングの輪廻転生 Invited

    樋口 知之

    京都大学情報学研究科創立20周年記念シンポジウム  ( 京都市 )   2018.9  京都大学大学院情報科学研究科

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  • 社内のデータサイエンティストやAI人材を育てる, 増やすTIPS Invited

    樋口 知之

    統計数理研究所創立75周年記念 産学連携シンポジウム 企業における デジタルトランスフォーメーションとデータサイエンティスト育成の最前 線,  ( 立川、東京 )   2018.6 

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  • Smart simulation and Smart experimental design Invited International conference

    Tomoyuki HIGUCHI

    NTNU-ISM Joint Workshop on Sustainability and Statistical Machine Learning  ( NTNU(Norway) )   2018.6 

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  • 深層学習による生成モデルの自動構築 Invited

    樋口 知之

    日本地球惑星科学2018年大会  ( 千葉県 幕張メッセ )   2018.5  公益社団法人日本地球惑星科学連合

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  • マシンのためのビッグデータ可視化技術:特徴ベクトルの自動選択とデータ解析法の野蛮化 Invited

    樋口 知之

    日本地球惑星科学2018年大会  ( 千葉県 幕張メッセ )   2018.5  公益社団法人日本地球惑星科学連合

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  • ビッグデータ、AI、IoT時代のオートメーションとその先 Invited

    樋口 知之

    アズビル・アカデミー講演会  ( 神奈川県藤沢市 )   2018.4  アズビル株式会社技術開発本部

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  • 深層学習はすべてを解決できるのか? Invited

    樋口 知之

    データサイエンティスト協会 セミナー2018 第1回  ( 東京 ユビキタス協創広場 CANVAS )   2018.4  一般社団法人データサイエンティスト協会

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  • 統計数理アプローチによる建設分野の技術革新の可能性 ~維持管理/防災・減災へのビッグデータ、AIの活用 Invited

    樋口 知之

    第22回土木鋼構造研究シンポジウム  2018.3 

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  • 超スマート社会に向けたデータサイエンス人材育成 Invited

    樋口 知之

    日経ユニバーシティ・コンソーシアム データサイエンスが拓く未来フォーラム2018  ( 大手町フィナンシャルシティ カンファレンスセンターホール )   2018.3 

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    ~スマートソサエティーを担う産学連携人材育成と経営視点からの最新ビジネスソリューション~

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  • ビッグデータ、AI時代に必要とされる統計的推論法の習得に必要な数学教育 Invited

    樋口 知之

    「教育数学」第3回シンポジウム  ( 京都大学数理解析研究所 )   2018.2  RIMS研究集会

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  • ものづくりにおける情報科学の基礎と応用 ~AI・IoT時代を見据えたデータ活用~ Invited

    樋口 知之

    住友ゴム工業株式会社タイヤテクニカルセンター講演会  ( 兵庫県神戸市 )   2018.2  住友ゴム工業株式会社タイヤテクニカルセンター

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  • Role of Statistical Mathematics in the Era of Big Data and AI Invited

    Tomoyuki HIGUCHI

    The 2nd JAIST-ISM symposium+KIST  2018.1 

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  • データ同化による携帯電話データを用いた大規模災害時の不規則な移動行動の予測

    須藤明人, 矢部貴大, 樫山武浩, 関本義秀, 樋口知之, 中野慎也, 齋藤正也

    第8回データ同化ワークショップ  2018.1 

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  • 生き残るのは誰だ!? ~統計数理からみる近未来~ Invited

    樋口 知之

    東京立川ロータリークラブ第2766回例会  2017.10 

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  • ニーズ駆動型イノベーションと気象ビジネス Invited

    樋口 知之

    日本気象協会 技術研究会  2017.10 

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  • 親のすすめる仕事は10年後には消滅!? Invited

    樋口知之

    宮崎県立大宮高等学校「大宮ハローワーク」  2017.9 

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  • データサイエンスが担うニーズ駆動型イノベーション Invited

    樋口知之

    山口大学データサイエンス講演会『人工知能とデータサイエンスによる新しい社会の創造』  2017.9 

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  • Smart Simulation with Sparse Modeling and Deep Learning International conference

    T. Higuchi

    MOU SIGNING CEREMONY & SEMINAR ISM^2  2017.9 

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  • 粒子フィルタと深層学習が拓くエミュレーション技術 Invited

    樋口知之

    第35回日本ロボット学会学術講演会(RSJ2017)  2017.9 

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  • シミュレーションをAIにつなぐ形 Invited

    樋口知之

    第64回理論応用力学講演会  2017.8 

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  • Smart simulation and smart experimental design Invited International conference

    T. Higuchi

    Conference of the International Federation of Classification Societies (IFCS-2017)  2017.8 

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  • データサイエンスを超えるヒント:内挿と外挿

    樋口知之

    岩波書店『岩波データサイエンスVol.6』刊行記念イベント  2017.7 

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  • 統計学と人工知能

    樋口知之

    島根大学医学部情報科学概論講義  2017.7 

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  • 人工知能の数理的基盤

    樋口知之

    平成29年度文部科学省関係機関職員研修生実地研修  2017.6 

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  • データサインエス:不確実な時代の羅針盤

    樋口知之

    滋賀大学データサイエンス教育ワークショップDS学部開設記念「高等教育におけるデータサイエンス教育の新たな展開」  2017.5 

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  • AIと外挿

    樋口知之

    さきがけ「計測技術と高度情報処理の融合によるインテリジェント計測・解析手法の開発と応用」第2回領域会議  2017.5 

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  • データサイエンスと巨大自然災害

    樋口知之

    第2回巨大自然災害の情報発信と人工知能フォーラム  2017.4 

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  • ビッグデータ時代に生きる力を育む情報デザイン学

    樋口知之

    工学院大学情報学部「情報学概論」  2017.4 

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  • 機械学習をより研究開発に活かすには Invited

    樋口知之

    コニカミノルタ講演会  2017.3 

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  • データサイエンス教育と臨床統計家育成コースへの期待

    樋口知之

    京都大学臨床統計家育成コースキックオフシンポジウム 医療系データサイエンス教育の新展開  2017.3 

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  • 異分野融合・新分野創成を担うデータサイエンティストの育成基盤

    樋口知之

    情報・システム研究機構シンポジウム「分野を超えたデータサイエンスの広がり」  2017.2 

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  • ISM's next challenge for big data and AI International conference

    T. Higuchi

    ISM-ZIB-IMI Joint Workshop on Optimization and Data-intensive High Performance Computing  2017.1 

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  • 機械学習をより実務に活用するためには Invited

    樋口知之

    MUFG勉強会  2016.12 

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  • ★これでいいのかデータサイエンス? Invited

    樋口知之

    SPC Open Reseach Forum 2016  2016.11  慶応義塾大学

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  • Particle filter for real-time human mobility prediction following unprecedented disaster International conference

    A. Sudo, T. Kashiyama, T. Yabe, H. Kanasugi, X. Song, T. Higuchi, S. Nakano, M. Saito, Y. Sekimoto

    24th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL 2016)  2016.11 

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  • 背景・状態空間モデルとカルマンフィルタ

    樋口知之

    平成28年度統計数理研究所公開講座「粒子フィルタとその応用」  2016.9 

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  • 実世界データの機械学習 Invited

    樋口知之

    センサエキスポジャパン2016-SICE計測部門・システムインテグレーション部門共催セミナー  2016.9 

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  • 社会で求められるデータサイエンス Invited

    樋口知之

    滋賀大学データサインエスシンポジウム  2016.9 

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  • 人工知能とビッグデータ 文系の仕事は無くなる!? Invited

    樋口知之

    宮崎大宮高校ハローワーク  2016.9 

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  • データ同化入門 Invited

    樋口知之

    iTHESデータ同化スクール  2016.9 

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  • 眼光紙背:ベイズ統計モデリングと人工知能 Invited

    樋口知之

    東京大学地震研究所金曜セミナー  2016.9 

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  • リアルタイムな広域人流推定のための高速で高精度な粒子フィルタの提案

    須藤明人, 樫山武浩, 矢部貴大, 樋口知之, 中野慎也, 斎藤正也, 関本義秀

    第36回交通工学研究発表会  2016.8 

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  • 社会で求められるデータサイエンス Invited

    樋口知之

    滋賀大学データサインエスシンポジウム  2016.7 

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  • モノづくりのスマート化の基盤と駆動力:ビッグデータと機械学習 Invited

    樋口知之

    JOEM Workshop'16「ビッグデータ・人工知能時代の機能性材料開発とは?」  2016.7 

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  • 非線形埋込み型特徴量選択のための単結合ニューラルネットワークの提案

    須藤明人, 樋口知之, 中野慎也, 斎藤正也, 矢部貴大, 関本義秀

    第25回情報論的学習理論と機械学習研究会  2016.7 

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  • メゾスコピック・モデリングに必要な技巧と教練 Invited

    樋口知之

    CREST「生命動態の理解と制御のための基盤技術の創出」第6回デザイン道場  2016.6 

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  • ビッグデータ、人工知能、そしてセレンディピティ Invited

    樋口知之

    第81回形の科学シンポジウム「量子科学とかたち」  2016.6 

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  • 予測とモデリング

    樋口知之

    島根大学医学部情報科学概論講義  2016.5 

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  • シミュレーションとデータ解析の融合計算の基礎

    樋口知之

    第1回MI^2I チュートリアルセミナー  2016.3 

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  • ビッグデータ、CPS、IoTを貫くもの Invited

    樋口知之

    SIP常設型モニタリング会議  2016.3 

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  • 今後の展望

    樋口知之

    文部科学省委託事業「データサイエンティスト育成ネットワークの形成」最終年度報告シンポジウム  2016.3 

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  • 日本におけるビッグデータ時代の人材ビッグバン計画 Invited

    樋口知之

    第10回日本統計学会春季集会  ( 東北大学 )   2016.3 

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  • 物理モデルと実験モデルの統合 Invited

    樋口知之

    第34回自動車制御とモデル研究専門委員会  2016.2 

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  • 簡便エミュレーションによる実験計画のスマート化 Invited

    樋口知之

    数学協働プログラムワークショップ-MI^2 (情報統合型物質・材料開発) と数学連携による新展開-  2016.2 

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  • 大規模観測科学と「知」のPDCAサイクル創り Invited

    樋口知之

    海洋研究開発機構 CEISTセミナー  2016.2 

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  • ICE-Xによるice coreの年代推定

    中野慎也, 鈴木香寿恵, 川村賢二, F. Parrenin, 樋口知之

    JAIST-ISMシンポジウム「データ同化・シミュレーション・乱数とHPCの新展開」  2016.1 

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  • データ駆動型イノベーションの神髄 Invited

    樋口知之

    第9回The KAITEKI講演会  2015.12 

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  • Data Assimilation: Challenge for Big Data through Numerical Simulation Invited International conference

    T. Higuchi

    2015 Taiwan-Japan Joint Workshop on Inverse Problems  2015.11 

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  • 人工知能とデータサイエンティストの役回り Invited

    樋口知之

    数理システムユーザーコンファレンス2015  2015.11 

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  • 逆解析数理とシミュレーションの融合による「ものづくり」の高度化 Invited

    樋口知之

    武蔵野大学数理工学シンポジウム2015  2015.11 

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  • 統計科学とビッグデータの利活用 Invited

    樋口知之

    国東市偉人顕彰プロジェクト・武蔵フォーラム  ( 大分県国東市 )   2015.11  武蔵中央公民館

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  • データ同化によるものづくり・サービスの革新 Invited

    樋口知之

    オムロン株式会社技術講演会  2015.11 

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  • ビッグデータを生かすデータサイエンス

    樋口知之

    リコー中央研究所講演会  2015.10 

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  • ビッグデータ時代に生きる力を育む情報デザイン学

    樋口知之

    工学院大学情報学部講義  2015.10 

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  • ビッグデータと人工知能

    樋口知之

    茨城大学理学部「情報数理特論III」講義  2015.10 

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  • 人工知能とビッグデータ 文系の仕事は無くなる!? Invited

    樋口知之

    宮崎大宮高校ハローワーク  2015.9 

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  • Road condition classification using a new global alignment Kernel International conference

    T. Goto, Y. Hanatsuka, T. Higuchi, T. Matsui

    IEEE International Workshop on Machine Learning for Signal Processing (MLSP)2015  ( Boston, USA )   2015.9 

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  • 南極氷床に適応した降雪量推定モデルの開発その2 -2009年の事例解析-

    鈴木香寿恵, 本山秀明, 山内恭, 平沢尚彦, 榎本浩之, 田村岳史, 飯塚芳徳, 的場澄人, 樋口知之

    雪氷研究大会  2015.9 

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  • 時系列モデルを用いた家庭の電力需要予測

    高橋久尚, 樋口知之, 今井純志, 志賀孝広

    2015年度統計関連学会連合大会  ( 岡山 )   2015.9 

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  • Simulation, Data Assimilation and Emulation Invited International conference

    T. Higuchi

    Asia Oceania Geosciences Society 2015 (AOGS)  ( Singapore )   2015.8 

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  • ビッグデータを取り巻く課題と公共インフラ構築・社会サービスのイノベーション Invited

    樋口知之

    中国地域ICT利活用研究会  ( 広島 )   2015.7  中国経済連合会

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  • 簡便エミュレーションによる実験計画の高速化 Invited

    樋口知之

    第1回設計に活かすデータ同化研究会  ( 立川市 )   2015.7  日本機械学会計算力学部門

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  • シミュレーションとエミュレーション:データ同化を超えて

    樋口知之

    ものづくり企業に役立つ応用数理手法の研究会 第6回技術セミナー  2015.6 

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  • Interaction, Integration, and Design: Key elements for success on promoting the interdisciplinary research Invited

    樋口知之

    iTHES理論科学セミナー  2015.6 

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  • システム科学技術に期待するもの Invited

    樋口知之

    第10回システム科学技術推進会議  2015.5 

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  • 予測とモデリング

    樋口知之

    島根大学医学部情報科学概論講義  2015.5 

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  • Estimation of the age-depth relationship of Dome Fuji Ice Core using a sequential Bayesian approach

    中野慎也, 鈴木香寿恵, 川村賢二, F. Parrenin, 樋口知之

    日本地球惑星科学連合2015年大会  2015.5 

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  • エミュレーション技術によるパーソナライゼーションの実現

    樋口 知之

    応用統計学フロンティアセミナー-社会科学型ビッグデータにおける応用統計学の活躍の場拡大を目指して-  2015.5 

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  • Big Data and Personalization Technology:Augmentation and Reduction Invited International conference

    Higuchi T

    Department of Mathematic, Hong Kong Baptist University  ( Hong Kong )   2015.4 

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  • Data Assimilation: Challenge for Big Data through Numerical Simulation Invited International conference

    Higuchi T

    Department of Mathematic, Hong Kong Baptist University  ( Hong Kong )   2015.4 

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  • A method for estimating the age-depth relationship of Dome Fuji Ice Core ushing a sequential Monte Carlo method International conference

    S. Nakano, K.Suzuki, K. Kawamura, F. Parrenin, T. Higuchi

    European Geosciences Union General Assembly 2015 (EGU)  ( Viena )   2015.4 

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  • 分野の壁を突き崩すビッグデータ

    樋口 知之

    平成27年度総合研究大学院大学フレッシュマン・コース“知のフロンティア”  2015.4 

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  • エミュレータ・デザインの基礎数理1:データ同化とスパース回帰

    樋口 知之

    電子情報通信学会東京支部シンポジウム「実験計画、データ同化、そしてエミュレータ・デザインへ」  2015.3 

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  • 磁力線固有振動数とTECの統合インバージョンによる磁気圏密度分布推定-経過報告-

    河野 英昭, 上野 玄太, 才田 聡子, 中野 慎也, 樋口 知之

    共同研究集会「電離圏・磁気圏モデリングとデータ同化」  ( 立川市 日本 )   2015.1 

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  • 低軌道デブリの突発的軌道減衰現象の全球構造を推定するための状態空間モデルの検討

    上津原正彦, 中野慎也, 樋口 知之

    共同研究集会「電離圏・磁気圏モデリングとデータ同化」  ( 立川 日本 )   2015.1 

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  • プラズマ圏の密度緯度分布パラメータの最尤法による推定

    中野慎也, Fok, Mei-Ching, Brandt, Pontus C, 樋口知之

    共同研究集会「電離圏・磁気圏モデリングとデータ同化」  ( 立川市 日本 )   2015.1 

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  • 機能のモデル化と真理の探求のバランス感覚

    樋口 知之

    「新学術領域研究」スパースモデリングの深化と高次元データ駆動科学の創生  ( 横浜市 日本 )   2014.12 

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  • ビッグデータ時代にマネジメントはどう向き合うべきか

    樋口 知之

    モノづくりにおける問題解決のためのデータサイエンス講演会  ( 東京都 日本 )   2014.12 

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  • わが国におけるデータ分析人材の育成と活用

    丸山宏, 神谷直樹, 樋口知之, 竹村彰通

    第5回横幹連合総合シンポジウム  ( 東京都 日本 )   2014.11 

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  • ビッグデータ奔流が破壊する理系・文系の壁

    樋口 知之

    2014年度(秋学期)文化情報学研究科シンポジウム  ( 京田辺市 日本 )   2014.11 

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  • 賢く増やすと減らすはビッグデータ解析の基本

    樋口 知之

    データサイエンティスト協会 1stシンポジウム~実務者が集うデータサイエンスの最前線~  ( 東京都 日本 )   2014.11 

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  • Stream computing and emulation in a world of the edge heavy data International conference

    T. Higuchi

    International Conference for Mathematics, Statistics and Financial Mathematics (ICMSFM2014)  2014.11 

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  • Simulation, Data assimilation, and Emulation International conference

    T. Higuchi

    Big Data Research Mission to UK  2014.11 

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  • Big data and personalization technology: Imputation, Linkage, and Stream computing Invited International conference

    Higuchi T

    International Conference on Statistical Analysis of Large Scale High Dimensional Socio-Economics Data  ( Sendai, Japan )   2014.11 

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  • Estimating the latitudinal dependence of plasmaspheric helium ion density based on data assimilation of the IMAGE/EUV data

    2014.10 

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  • Merging particle smootherによる南極氷床コアの年代推定

    中野慎也, 鈴木香寿恵, 樋口知之, 川村賢二

    パーティクルフィルタ研究会「データ同化と粒子フィルタの接点」  ( 東京都 日本 )   2014.10 

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  • GPS時系列データに基づく断層すべりの時空間変化の推定

    福田淳一, 樋口知之, 宮崎真一

    パーティクルフィルタ研究会「データ同化と粒子フィルタの接点」  ( 東京都 日本 )   2014.10 

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  • 連結SIRモデルのパラメータ推定

    齋藤正也, 樋口知之, 井元清哉, 山口類, 宮野悟

    パーティクルフィルタ研究会「データ同化と粒子フィルタの接点」  ( 東京都 日本 )   2014.10 

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  • ビッグデータがせまる社会の本格的な知能化 Invited

    樋口 知之

    地球環境カレッジ第131回定例講演会  ( 東京都 日本 )   2014.10 

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  • 連結SIRモデルを使った日本のインフルエンザ流行における地域間相互作用の推定

    齋藤 正也, 井元 清哉, 山口 類, 宮野 悟, 樋口 知之

    第63回理論応用力学講演会  ( 東京都 日本 )   2014.9 

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  • データ同化技術を用いた投薬・治療の未来像 Invited

    樋口 知之

    第18回関東ハートセミナー  ( 東京都 日本 )   2014.9 

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  • 「個客」マーケティングのためのベイジアンモデリング入門 Invited

    樋口 知之, 佐藤 忠彦

    ビッグデータカンファレンス 2014 Autumn  ( 東京都 日本 )   2014.9 

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  • Evaluation of the Reliability and Validity of Magnetosphere-ionosphere Coupling Process in the Global Mhd Simulation Based on the Ionospheric Plasma Drift Obtained from SuperDARN Measurements

    Saita S, Fujita S, Kadokura A, Tanaka T, Yukimatsu A, Tanaka Y, Ohtani S, Murata T, Higuchi T

    AOGS2014  2014.7 

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  • Temporal evolution of helium lon density distribution estimated by assimilation of IMAGE/EUV data into a plasmasphere model International conference

    Nakano S, Fok, M-C, Bra, t, P. C, Higuchi T

    AOGS2014  2014.7 

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  • Evaluation of the reliability and validity of Magnetosphere-Ionosphere coupling process in the global MHD Simulation for the Earth's Magnetosphere International conference

    Saita S, Fujita S, Kadokura A, Tanaka T, Yukimatsu A, Tanaka Y, Ohtani S, Murata T, Higuchi T

    2014 Chinese Institute of Probability and Statistics Annual Meeting  ( Taiwan )   2014.6 

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  • データ同化によるエミュレータ・デザイン学の創設 Invited

    樋口 知之

    バイオスーパーコンピューティング東北2014  ( 仙台市 日本 )   2014.6 

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  • 木を見て森も見るビッグデータ解析技術 Invited

    樋口 知之

    第68回技研公開2014  ( 東京 日本 )   2014.5 

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  • 人への投資を触媒とするビッグデータからの価値創出 Invited

    樋口 知之

    サイエンティフィック・システム研究会第36回通常総会  ( 東京 日本 )   2014.5 

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  • プラズマ対流速度の磁気圏電離圏結合シミュレーションから得られる計算値とSuperDARNHFレーダーデータから得られる観測値の比較

    才田 聡子, 藤田 茂, 門倉 昭, 田中 高史, 行松 彰, 田中 良昌, 大谷 晋一, 村田 健史, 樋口 知之

    日本地球惑星科学連合2014年大会  ( 横浜市 日本 )   2014.4 

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  • Inversion method for estimating the helium ion density distribution in the plasmasphere based on IMAGE/EUV data

    中野 慎也, Fok M-C, Bra, dt P. C, 樋口 知之

    日本地球惑星科学連合2014年大会  ( 横浜市 日本 )   2014.4 

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  • 同床異夢のビッグデータ Invited

    樋口 知之

    日経ビッグデータ創刊記念フォーラム  ( 東京 日本 )   2014.4 

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  • 次世代磁気圏−電離圏結合系シミュレーションとIUGONET開発ツール(UDAS)との連携による電離圏プラズマ対流速度の計算値と観測値の比較

    才田 聡子, 藤田 茂, 門倉 昭, 田中 高史, 行松 彰, 田中 良昌, 大谷 晋一, 村田 健史, 樋口 知之

    平成25年度名古屋大学太陽地球環境研究所 研究集会 「太陽地球環境メタデータ・データベースによる時空間変動の学際研究」  ( 名古屋 日本 )   2014.3 

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  • Sequential data assimilation and stream computing for big data Invited International conference

    Higuchi T

    UK-Japan Big Data Research Workshop&Seminar  2014.2  Tokyo, Japan

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  • 「データサイエンティスト育成ネットワークの形成」事業の概要

    丸山 宏, 樋口 知之, 竹村 彰通

    第5回横幹連合コンファレンス  ( 高松市 日本 )   2013.12 

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  • ビジネスにおけるビッグデータと統計学〜受益者起点と予測モデル〜 Invited

    樋口 知之

    日経産業新聞フォーラム2013「今、注目されるデータサイエンスを経営に活かす〜ビッグデータ時代のデータオリエンテッドな企業経営〜」  ( 東京 日本 )   2013.12 

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  • データ同化によるエミュレータ・デザイン

    樋口 知之

    第18回先端的データベースとWeb技術動向講演会  ( 東京 日本 )   2013.12 

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  • ビッグデータがせまる人への投資とサービスの高度化 Invited

    樋口 知之

    ビッグデータ&オープンデータ研究会 in 九州  ( 福岡 日本 )   2013.12 

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  • ビッグデータ時代にマネジメントはどう向き合うべきか Invited

    樋口 知之

    クオリティフォーラム2013  ( 東京 日本 )   2013.11 

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  • ビッグデータが促す統計学の大飛躍 Invited

    樋口 知之

    日本計算機統計学会第27回シンポジウム  ( 熊本市 日本 )   2013.11 

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  • 逆推論とデータサイエンティスト

    樋口 知之

    京都大学国際高等教育院  ( 京都市 日本 )   2013.11 

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  • 不確実な情報下における予測戦略

    樋口 知之

    第72回日本公衆衛生学会総会  ( 三重 日本 )   2013.10 

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  • ビッグデータビジネスの現状と今後の展望-双方向性、受益者起点、そして制御可能性- Invited

    樋口 知之

    産業研究会講演会  ( 東京 日本 )   2013.10 

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  • Panel Disccusion "Key Issues in Big Data" International conference

    T. Higuchi

    IEEE International Conference on Big Data 2013  ( Santa Clara U.S.A. )   2013.10 

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  • システムののスマート化を支える数理基盤技術 Invited

    樋口 知之

    計測自動制御学会スマートセンシングシステム部会 SICE計測部門セミナー  ( 東京 日本 )   2013.9 

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  • ビッグデータと統計学をつなぐもの Invited

    樋口 知之

    第11回地球シミュレータシンポジウム−さらなる社会・未来・安心への貢献を目指して−  ( 東京都 日本 )   2013.9 

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  • 2009年の日本におけるインフルエンザ動向における地域間相互作用の影響

    齋藤 正也, 井元 清哉, 山口 類, 坪倉 正治, 上 昌広, 中田 はる佳, 佐藤 弘樹, 宮野 悟, 樋口 知之

    2013年度統計関連学会連合大会  ( 大阪市 日本 )   2013.9 

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  • 地震音波データ同化システムの開発

    長尾 大道, 樋口 知之

    2013年度統計関連学会連合大会  ( 大阪市 日本 )   2013.9 

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  • ビッグデータを活用したビジネス戦略:何が技術者に足りないのか? Invited

    樋口 知之

    第2回日立辺仁会フォーラム  ( 京都市 日本 )   2013.8 

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  • 公共サービスにおけるビッグデータの利活用の問題点と心構え

    樋口 知之

    海上保安庁交通部企画課  ( 東京都 日本 )   2013.7 

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  • Estimation of abrupt changes in sentinel observation data of influenza epidemics in Japan International conference

    Saito M, Imoto S, Yamaguchi R, Miyano S, Higuchi T

    16th International Conference on Information FUSION  ( Istanbul Turkey )   2013.7 

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  • Data assimilation system for seismoacoustic waves International conference

    Nagao H, Higuchi T

    16th International Conference on Information FUSION  ( Istanbul Turkey )   2013.7 

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  • ビッグデータ時代にマネジメントはどう向き合うべきか Invited

    樋口 知之

    アナリティクス・カンファレンス2013  ( 東京 日本 )   2013.6 

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  • グローバルMHDシミュレーションモデルの磁気圏?電離圏結合領域におけるパラメータ感受性

    才田 聡子, 門倉 昭, 藤田 茂, 樋口 知之

    日本地球惑星科学連合2013年大会  ( 千葉 日本 )   2013.5 

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  • IMAGE/EUVデータの同化によって推定したプラズマ圏イオン分布

    中野 慎也, Fok, M-C, Br, P. C, 樋口 知之

    日本地球惑星科学連合2013年大会  ( 千葉 日本 )   2013.5 

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  • クラウドコンピューティングシステムを利用した地球物理データの多変量時系列解析

    長尾 大道, 樋口 知之

    日本地球惑星科学連合2013年大会  ( 千葉 日本 )   2013.5 

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  • ビッグデータが開く新しい科学像 Invited

    樋口 知之

    日本地球惑星科学連合2013年大会  ( 千葉 日本 )   2013.5 

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  • ビッグデータで改めて浮き彫りとなった日本のシステム科学の課題

    樋口 知之

    横断型基幹科学技術研究団体連合2013年度定時総会  ( 東京 日本 )   2013.4 

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  • データを駆使する企業に生まれ変わるには Invited

    樋口 知之

    Bigdata Innovation Comference  ( 東京都 日本 )   2013.4 

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  • データ同化を用いた線虫C. elegans における細胞質流動を引き起こす細胞内力分布の推定

    庭山 律哉, 長尾 大道, 樋口 知之, 木村 暁

    第62 回理論応用力学講演会(NCTAM2013)  ( 東京 日本 )   2013.3 

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  • マルコフ連鎖モンテカルロ法を利用したトレーサー試験からフラク チャーの物理パラメータを推定する方法

    長尾 大道, 佐藤 光三, 樋口 知之

    第62 回理論応用力学講演会(NCTAM2013)  ( 東京 日本 )   2013.3 

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  • 地球磁気圏MHD シミュレーションモデルのモデルパラメータ最適値推定

    才田 聡子, 門倉 昭, 藤田 茂, 田中 高史, 大谷 晋一, 樋口 知之

    第62 回理論応用力学講演会(NCTAM2013)  ( 東京都 日本 )   2013.3 

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  • グローバルMHDシミュレーションで再現される電離圏電位分布のモデルパラメータ依存性について

    才田 聡子, 門倉 昭, 藤田 茂, 田中 高史, 行松 彰, 大谷 晋一, 村田 健史, 樋口 知之

    名古屋大学太陽地球環境研究所・研究集会「地域ネットワークによる宇宙天気の観測・教育活動に関する研究集会」  ( 福岡市 日本 )   2013.3 

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  • データ同化によるモデルの高度化〜物質材料研究への応用〜 Invited

    樋口 知之

    「データを活用した機能に基づく新物質・材料の設計(マテリアルインフォマティクス)」分科会  ( 東京都 日本 )   2013.2 

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  • ビッグデータが拓く新しい情報通信の世界(〜サイバーとリアルの間を取り持つデータ同化技術を中心として〜)

    樋口 知之

    電子情報通信学会 東京支部講演会「ビッグデータが拓く新しい情報通信の世界」  ( 東京都 日本 )   2012.12 

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  • Development of the roadsurface condition classification system International conference

    Hanatsuka Y, Higuchi T, Matsui T

    2012 IET International Conference on Information Science and Control Engineering (ICISCE)  ( Shenzhen China )   2012.12 

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  • Time-Series Modeling of Tide Gauge Records for Monitoring of the Crustal Activities Related to Oceanic Trench Earthquakes around Japan International conference

    Nagao H, Higuchi T, Miura S, Inazu D

    AGU Fall Meeting 2012  ( San Francisco U.S.A. )   2012.12 

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  • Towards efficient improvement of transcriptional circuit models by Life Science Data Assimilation System (LiSDAS) Invited International conference

    4th Biosupercomputing Symposium  2012.12 

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  • Prediction, Design, and Data assimilation Invited International conference

    Higuchi T

    2012 International Conference on Modeling, Analysis and Simulation (ICMAS)  ( Tokyo Japan )   2012.11 

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  • 予測と計測デザインを高度化するデータ同化 Invited

    樋口 知之

    第21回 Future of Radiology  ( 東京都 日本 )   2012.11 

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  • グローバルMHDシミュレーションを用いたオーロラの形状と動きの南北両半球非対称性の研究

    才田 聡子, 門倉 昭, 佐藤 夏雄, 藤田 茂, 田中 高史, 海老原 祐輔, Ohtani Shinichi, 村田 健史, 樋口 知之

    第132回 地球電磁気・地球惑星圏学会  ( 札幌市 日本 )   2012.10 

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  • Two-dimensional structure of the plasmasphere estimated by the ensemble transform Kalman filter

    2012.10 

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  • Coseismic atmospheric and ionospheric variations detected at the Sugadaira Space Radio Observatory

    2012.10 

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  • 出口指向のビッグデータ研究開発 Invited

    樋口 知之

    ビッグデータと統計学研究集会第1回研究集会  ( 札幌市 日本 )   2012.10 

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  • Data Assimilation: Challenge for Big Data through Numerical Simulation Invited International conference

    Higuchi T

    Ninth International Conference on Flow Dynamics (ICFD2012)  ( Sendai, Japan )   2012.9 

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  • インフルエンザ介入制作における集団免疫を高めるワクチン接種対象群の選択

    齋藤 正也, 井元 清哉, 山口 類, 坪倉 正治, 上 昌広, 中田 はる佳, 佐藤 弘樹, 宮野 悟, 樋口 知之

    統計関連学会連合大会  ( 札幌市 日本 )   2012.9 

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  • クラウドコンピューティングを利用したデータ同化システムの開発(II)

    長尾 大道, 本橋 永至, 樋口 知之

    統計関連学会連合大会  ( 札幌市 日本 )   2012.9 

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  • 潮位解析による過去のプレート境界型地震に伴う地殻変動の検出

    長尾 大道, 樋口 知之, 三浦 哲, 稲津 大祐

    統計関連学会連合大会  ( 札幌市 日本 )   2012.9 

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  • 時系列モデルを用いたインターネット広告の効果予測

    本橋 永至, 磯崎 直樹, 長尾 大道, 樋口 知之

    統計関連学会連合大会  ( 札幌市 日本 )   2012.9 

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  • Spatial and temporal variability of snow accumulation rate and air transports at East Antarctic ice sheet in 1993-2010 International conference

    Suzuki K, Motoyama H, Yamanouchi T, Kawamura K

    XXXII SCAR  ( Portland U.S.A. )   2012.7 

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  • Weight adjustment of the particle filter on distributed computing systems International conference

    Nakano S, Higuchi T

    15th International Conference on Information Fusion  ( Singapore )   2012.7 

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  • Data assimilation of the earth's atmospheric and ionospheric oscillations excited by large earthquakes International conference

    Nagao H, Higuchi T

    15th International Conference on Information Fusion  ( Singapore )   2012.7 

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  • Identifiability of local transmissibility parameters in agent-based pandemic simulation International conference

    Saito M, Imoto S, Yamaguchi R, Miyano S, Higuchi T

    15th International Conference on Information Fusion  ( Singapore )   2012.7 

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  • Data assimilation and sequential Bayes filters: Information fusion with numerical simulation Invited International conference

    Higuchi T

    ISBA2012  ( Kyoto, Japan )   2012.6 

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  • ビッグデータが照らす新しい研究道

    樋口 知之

    統計数理研究所オープンハウス  ( 立川市 日本 )   2012.6 

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  • 高速な生命体データ同化システムの開発とパスウェイ・モデル探索への応用

    齋藤 正也, 吉田 亮, 長尾 大道, 中野 慎也, 樋口 知之

    京コンピュータ・シンポジウム2012  ( 神戸市 日本 )   2012.6 

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  • アンサンブルベース逐次データ同化とHPC

    樋口 知之

    CPSセミナー  ( 神戸市 日本 )   2012.6 

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  • Estimation of the spatial structure of the plasmasphere using a data assimilation technique

    Nakano S, Fok M-C, Bra, dt P. C, Higuchi T

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • 地上磁場観測とGPS TEC観測からのプラズマ圏密度推定に向けて

    河野 英昭, 才田 聡子, 上野 玄太, 樋口 知之, 中野 慎也, 湯元 清文

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • ドームふじアイスコアの年代補正モデルによる年代軸決定の試み

    鈴木 香寿恵, 川村 賢二, Frederic P, 阿部 彩子, 齋藤 冬樹, 藤田 秀二, 樋口 知之

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • 夜側中緯度静穏時地磁気H成分の長期変動

    中野 慎也, 長尾 大道, 樋口 知之

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • 地殻活動起源の大気変動をモニタリングするための微気圧連続観測

    長尾 大道, 冨澤 一郎, 家森 俊彦, 金尾 政紀, 徳永 旭将, 樋口 知之

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • 大地震によって励起される大気変動および電離層変動のモデリング

    長尾 大道, 小林 直樹, 深尾 良夫, 冨澤 一郎, 樋口 知之

    日本地球惑星科学連合2012年大会  ( 千葉市 日本 )   2012.5 

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  • ビッグデータが迫る研究開発の変革 Invited

    樋口 知之

    経済産業研究所BBLセミナー  ( 東京都 日本 )   2012.5 

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  • Fault parameter estimation from coseismic infrasound variation excited by a large earthquake International conference

    ( Vienne Austria )   2012.4 

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  • Applicability of the particle filter for high-dimensional problems using a massively parallel computer International conference

    Nakano S, Higuchi T

    ( Vienne Austria )   2012.4 

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  • Modeling of atmospheric and ionospheric disturbances excited by a large earthquake - In the case of the 2008 Iwate-Miyagi Nairiku earthquake - International conference

    Nagao H, Kobayashi N, Fukao Y, Tomizawa I, Higuchi T

    ( Vienne Austria )   2012.4 

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  • Estimation of the long-term component of the variation in geomagnetic data International conference

    Nakano S, Higuchi T

    ( Vienne Austria )   2012.4 

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  • Generating Artistic Character Facial Animation Based on Motion Capture Data International conference

    Hirose K, Higuchi T

    The 2012 International Workshop on Advanced Image Technology  ( Ho Chi Minh Vietnam )   2012.1 

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  • LiSDAS:データ同化計算技術に基づく生体情報シミュレーション

    樋口 知之

    ISLiM成果報告会2011  ( 東京都 日本 )   2011.12 

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  • データ同化を利用した乱流の適応型シミュレーション

    加藤 博司, 大林 茂, 橋本 敦, 吉澤 徴, 上野 玄太, 樋口 知之

    第25回数値流体力学シンポジウム  ( 吹田市 日本 )   2011.12 

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  • データ同化とスーパーコンピュータ「京」−個別化医療サービスの実現に向けた計算技術の開発ー

    樋口 知之

    科学研究費によるシンポジューム「生物統計における統計的推測とその応用」  ( 宮崎市 日本 )   2011.12 

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  • An approach for exploring the dynamics of the plasmasphere using data assimilation of IMAGE/EUV data International conference

    Nakano S, Fok M-C, Bra, dt P. C, Higuchi T

    AGU Fall Meeting 2011  ( San Francisco U.S.A. )   2011.12 

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  • 市場反応の構造的変化を仮定したブランド選択行動の解析

    本橋 永至, 樋口 知之

    第90回日本マーケティング・サイエンス学会  ( 東京 日本 )   2011.12 

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  • Modeling of the plasmasphere using data assimilation of IMAGE/EUV data International conference

    中野 慎也, Fok M-C, Br, dt P. C, Higuchi T

    第130回SGEPSS総会  ( 神戸 日本 )   2011.11 

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  • FLR地上磁場観測とTEC観測からのプラズマ圏3次元密度分布推定法 International conference

    河野 英昭, 才田 聡子, 上野 玄太, 樋口 知之, 中野 慎也, 湯元 清文

    第130回SGEPSS総会  ( 神戸 日本 )   2011.11 

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  • Timing relation between positive bay onsets, Pi2 onsets, auroral initial brightenings and auroral breakups International conference

    徳永 旭将, 中村 和幸, 樋口 知之, 魚住 禎司, 吉川 顕正, 森岡 昭, 湯元 清文, MAGDAS, CPMNグループ

    第130回SGEPSS総会  ( 神戸 日本 )   2011.11 

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  • データ同化による半現実世界の実現〜オンライン情報統合とアンサンブル予測の計算基盤〜

    樋口 知之

    電子情報通信学会パターン認識とメディア理解研究会(PRMU研究会)  ( 千葉市 日本 )   2011.10 

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  • 基調講演【開設記念市民講演会】 Invited

    樋口 知之

    明治大学先端数理科学研究科開設記念シンポジウム  ( 東京都 日本 )   2011.10 

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  • 階層ベイズ状態空間モデルを用いた消費者来店行動の解析

    佐藤 忠彦, 樋口 知之

    マーケティングの統計モデリング研究部会  ( 仙台 日本 )   2011.9 

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  • 市場反応の構造的変化を仮定したブランド選択行動の解析

    本橋 永至, 樋口 知之

    マーケティングの統計モデリング研究部会  ( 仙台 日本 )   2011.9 

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  • 大地震によって励起される地震音波の伝搬特性

    長尾 大道, 小林 直樹, 深尾 良夫, 樋口 知之, 石原 靖, 坪井 誠司

    電離圏・磁気圏モデリングとデータ同化研究集会  ( 名古屋 日本 )   2011.9 

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  • 極端紫外光データを用いたプラズマ圏構造の推定?現状あるいは課題

    中野 慎也, Fok M-C, Bra, dt P. C, 樋口 知之

    電離圏・磁気圏モデリングとデータ同化研究集会  ( 名古屋 日本 )   2011.9 

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  • 減災とデータ同化

    樋口 知之

    電離圏・磁気圏モデリングとデータ同化研究集会  ( 名古屋 日本 )   2011.9 

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  • Merging particle filterによる地磁気長期変動成分の抽出

    中野 慎也, 樋口 知之

    統計関連学会連合大会  ( 福岡市 日本 )   2011.9 

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  • クラウドコンピューティングを利用したデータ同化システムの開発 (序)

    長尾 大道, 樋口 知之

    統計関連学会連合大会  ( 福岡市 日本 )   2011.9 

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  • A state-space approach to capturing market dynamics for frequently purchased products International conference

    Motohashi E, Higuchi T

    2011 Joint Statistical Meetins (JSM)  ( Florida U.S.A. )   2011.8 

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  • A State-Space Approach to Capturing Market Dynamics for Frequently Purchased Products International conference

    Motohashi E, Higuchi T

    2011 Joint Statistical Meetings  ( Florida U.S.A. )   2011.8 

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  • Estimation of macroscopic parameter in agent-based pandemic simulation International conference

    Saito M, Imoto S, Yamaguchi R, Miyano S, Higuchi T

    FUSION2011  ( Chicago U.S.A. )   2011.7 

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  • Fault parameter estimation with data assimilation on infrasound variations due to big earthquakes International conference

    Nagao H, Kobayashi N, Nakano S, Higuchi T

    FUSION2011  ( Chicago U.S.A. )   2011.7 

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  • Embedding reality in a numerical simulation with data assimilation International conference

    Higuchi T

    FUSION2011  ( Chicago U.S.A. )   2011.7 

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  • Anti-correlation between the quiet-time level of mid-latitude magnetic field and long-term solar-wind activity International conference

    Nakano S, Nagao H, Higuchi T

    IUGG 2011  ( Melborne Australia )   2011.7 

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  • Displacement of conjugate point during a substorm in a global MHD simulation International conference

    Saita S, Kadokura A, Sato N, Fujita S, Tanaka T, Ebihara Y, Ohtani S, Ueno G, Murata K, Higuchi T

    IUGG 2011  ( Melborne Australia )   2011.7 

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  • Data Assimilation of EUV Imaging Data into a Plasmasphere Model International conference

    Nakano S, Fok M-C, Bra, dt P. C, Higuchi T

    IUGG 2011  ( Melborne Australia )   2011.7 

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  • Massively parallel particle filter and a grouping strategy International conference

    Nakano S, Higuchi T

    IUGG2011  ( Melborne Australia )   2011.7 

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  • 市場のダイナミクスと消費者の購買特性を考慮したプロモーション効果測定

    本橋 永至, 樋口 知之

    第42回消費者行動研究コンファレンス「消費者行動研究のクロスボーダー」  ( 東京 日本 )   2011.6 

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  • Dynamic Bayesian modelling of biological pathways and decoupling of hidden regulatory signals using nonlinear state space models International conference

    Yoshida R, Nagao H, Saitoh M, Higuchi T

    Yeditepe International Research Conference on Bayesian Learning (YIRCoBL'11)  ( Istanbul Turkey )   2011.6 

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  • Hybrid Bayesian filter algorithm for multivariate time-series modellings on cloud computing systems International conference

    Nagao H, Yoshida R, Higuchi T

    YIRCoBL'11  ( Istanbul Turkey )   2011.6 

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  • Modeling dynamics of consumer preference and promotion effect in brand choices International conference

    Motohashi E, HiguchiT

    33rd INFORMS Marketing Science Conference  ( Texas U.S.A. )   2011.6 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Estimation of temporal evolution of the plasmasphere using IMAGE/EUV data International conference

    樋口 知之, 中野 慎也, Fok M-C, B, P. C

    日本地球惑星科学連合大会  ( 千葉 日本 )   2011.5 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 静穏時地磁気H成分と太陽風活動長期変動との関係

    中野 慎也, 長尾 大道, 樋口 知之

    日本地球惑星科学連合2011年大会  ( 千葉市 日本 )   2011.5 

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    Language:Japanese   Presentation type:Poster presentation  

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  • Singular Value Transformation を用いた地上磁場からのサブストームオンセットの同定 International conference

    徳永 旭将, 湯元 清文, 魚住 禎司, 吉川 顕正, 中村 和幸, 樋口 知之, 池田 大輔, MAGDAS, CPMNグループ

    日本地球惑星科学連合2011年大会  ( 千葉市 日本 )   2011.5 

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  • グローバルMHDシミュレーションによるサブストーム時の磁気圏近尾部磁場構造の再現

    才田 聡子, 門倉 昭, 佐藤 夏雄, 藤田 茂, 田中 高史, 海老原 祐輔, 大谷 晋一, 上野 玄太, 村田 健史, 松岡 大祐, 樋口 知之

    日本地球惑星科学連合2011年大会  ( 千葉市 日本 )   2011.5 

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  • 地上磁場と GPS TEC の同時観測データを用いるプラズマ圏密度分布推定 International conference

    河野 英昭, 才田 聡子, 上野 玄太, 樋口 知之, 中野 慎也, 湯元 清文

    日本地球惑星科学連合2011年大会  ( 千葉市 日本 )   2011.5