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

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Language：Japanese   Publishing type：Research paper (international conference proceedings)  

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

Service providers want to know user attributes and recorded information in order to improve more satisfaction of the people, or the efficiency of their services by offering services specialized to the users' preferences. However, since they choose wrong way to collect, classify, analysis, use or disclose to others, of personal information, it may exceed the explicit or implicit of the user regarding the provision of personal information. So far, many anonymization methods for those data have been proposed to solve this problem. As one of anonymous method, we focus on k-anonymization technique to realize a "'forest from the trees' as described above. In papers in which these methods are proposed, only qualitative analyze or examples are shown that demonstrate the usefulness of anonymized data, which are the outputs of those methods. Since it is generally said that, if the size of data gets bigger, the anonymization of data becomes easier, those methods have not been applied to real huge data. In this paper, we transform the travel records of 722,000 people traveling by train in the Tokyo area with our proposed anonymization methods, analyze the degree to which each of the results is useful, and conclude that the results are useless even when anonymity level is set to low.

DOI： 10.1109/ICSMC.2012.6377859

Web of Science

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Language：English   Publishing type：Research paper (bulletin of university, research institution)  

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

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPRINGER-VERLAG BERLIN  

Efficient object searching mechanisms are essential in large-scale networks. Many studies have been done on distributed hash tables (DHTs), which are a kind of peer-to-peer system. In DHT networks, we can certainly get the desired objects if they exist. However, multi-word searches generate much communication traffic. Many studies have tried to reduce this traffic by using bloom filters, which are space-efficient probabilistic data structures. In using such filters, all nodes in a DHT must share their false positive rate parameter. However, the best false positive rate differs from one node to another. In this paper, we provide a method of determining the best false positive rate, and we use a new filter called a flexible bloom filter, to which each node can set the approximately best false positive rate. Experiments showed that the flexible bloom filter was able to greatly reduce the traffic.

DOI： 10.1007/978-3-642-11368-0_9

Web of Science

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Language：Japanese   Publisher：The Institute of Electronics, Information and Communication Engineers  

CiNii Books

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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

In the near future, applications with location-aware capabilities could be major development targets in the software industry. The current development frameworks rarely pay attention to developing applications for multiple ubiquitous environments. From the perspective of porting or updating applications, there are two dependencies: spatial and localized. These are dependencies on a single environment in which an application is deployed. We propose a new framework that uses a spatio-temporal scope (STS) model to ease deployment of location-aware applications by lessening these dependencies. We describe our model and explain the roles of the STS in the development stages of an application.

DOI： 10.1109/PERCOMW.2007.57

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Language：Japanese  

J-GLOBAL

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Language：Japanese  

J-GLOBAL

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Language：English   Publisher：IEEE Computer Society  

DOI： 10.1109/CIMCA.2006.174

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

In distributed hash tables, much communication traffic comes from multi-word searches. The aim of this work is to reduce the amount of traffic by using a bloom filter, which is a space-efficient probabilistic data structure used to test whether or not an element is a member of a set. However, bloom filters have a limited role if several sets have different numbers of elements. In the proposed method, extra data storage is generated when contents' keys are registered in a distributed hash table system. Accordingly, we propose a "divided bloom filter" to Solve the problem of a normal bloom filter. Using the divided bloom filter, we aim to reduce both the amount of communication traffic and the amount of data storage.

Web of Science

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Language：Japanese  

J-GLOBAL

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

In future ubiquitous environments, contents (data, movie, text, graphics, etc.) will be more sophisticated and context-aware so that they can enrich user experience. We have proposed the Active Contents (AC) framework, which is based on contents encapsulation with program and aspect definition to allow contents to behave actively. AC can be seen as a software component with several viewpoints of contributors (planner, designer, programmer, etc.). The problem is about maintainability of AC which is modified by the contributors based on their own viewpoints.
In this position paper, we propose a mechanism to allow such contributors to modify AC with context-aware aspect. In our mechanism, based on location binding analysis for AC, parallel executions to be performed at a sepaxate location axe detected and automatically executed using workflow-aware communication.

DOI： 10.1007/11575863_7

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Language：English  

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Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publisher：INSTICC Press  

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

We describe a methodology which enables development of flexible and reusable mobile agent applications for location aware indoor environments. The methodology, which is named "Workflow-awareness model" (WFA), is based on a concept where a pair of mobile agents cooperate to perform a given task to realize separation of concerns for software maintenance. The paper outlines the methodology, and shows how the concepts work in the prototype environment. Usefulness of this methodology concerning its efficiency and software engineering aspects are analyzed.

DOI： 10.1007/978-3-540-30178-3_2

Web of Science

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Language：Japanese   Publishing type：Research paper (scientific journal)  

A methodology which enables a flexible and reusable development of mobile agent application to a mobility aware indoor environment is provided in this study. The methodology is named Workflow-awareness model based on a concept of a pair of mobile agents cooperating to perform a given task. A monolithic mobile agent application with numerous concerns in a mobility aware setting is divided into a master agent (MA) and a shadow agent (SA) according to a type of tasks. The MA executes a main application logic which includes monitoring a user's physical movement and coordinating various services. The SA performs additional tasks depending on environments to aid the MA in achieving efficient execution without losing application logic. "Workflow-awareness (WFA) " means that the SA knows the MA's execution state transition so that the SA can provide a proper task at a proper timing. A prototype implementation of the methodology is done with a practical use of AspectJ. AspectJ is used to automate WFA by weaving communication modules to both MA and SA. Usefulness of this methodology concerning its efficiency and software engineering aspects are analyzed. As for the effectiveness, the overhead of WFA is relatively small to the whole expenditure time. And from the view of the software engineering, WFA is possible to provide a mechanism to deploy one application in various situations.

DOI： 10.1527/tjsai.19.311

Scopus

J-GLOBAL

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Language：Japanese  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Event date： 2006.7 　 　

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Event date： 2005.3 　 　

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Event date： 2004.3 　 　

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Event date： 2004.3 　 　

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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