Faculty Profiles - FUNABIKI Nobuo

MISC - FUNABIKI Nobuo

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Proposal of Reputation System with Strong Secrecy for Managers

NOMURA Tomoya, NAKANISHIV Toru, FUNABIKI Nobuo

Technical report of IEICE. ISEC 111 ( 337 ) 15 - 20 2011.12

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

In a P2P service such as Internet auctions, there is need for keeping users anonymous, but, in this case, misbehaving user becomes a problem. So, the anonymous users use a reputation system to evaluate each other, where the user can decide whether the other user is misbehaving user or not. However, in the system, the administrator can grasp the change of user's reputation point, it becomes a problem of privacy. In this study, we propose a reputation system with the anonimity even for the administrator by user's managing reputation points in the anonymous certificate. We evaluate the proposed system by processing time of the implementation.

Modeling and Performance Evaluation of Colluding Attack in Volunteer Computing

WATANABE Kan, FUNABIKI Nobuo, NAKANISHI Toru, FUKUSHI Masaru

IEICE technical report. Dependable computing 111 ( 252 ) 25 - 30 2011.10

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

This paper proposes a model of a colluding attack in Volunteer Computing (VC), where some of participants are unreliable and may return incorrect results. The colluding attack is one of the most important issues to realize reliable VC because it may ruin the most basic requirement, i.e. "the majority in voting is correct". It is used in most current sabotage-tolerance techniques such as M-first voting. Especially, checkbyvoting archives the largest efficiency in current sabotage-tolerance techniques by using the technique called "check by voting" (using the result of a voting as a check). Thus, if some results of votings have been incorrect by colluding attack, it may have significant impacts on checkbyvoting. In this paper, we perform a Monte Carlo simulation of VC using the proposed model and evaluate the sabotage-tolerance performance for both checkbyvoting and M-first voting.

An Implementation of an Anonymous Authentication System with Exclusion of Illegal Users in the Web Services

2011 ( 3 ) 66 - 71 2011.10

An Implementation of Anonymous Attributes Authentication System for Web Services

2011 ( 3 ) 60 - 65 2011.10

An Improvement of Active Access-Point Selection Algorithm for Throughput Maximization in Wireless Mesh Networks

SHIMIZU Junki, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan

IEICE technical report 111 ( 232 ) 25 - 30 2011.10

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

The wireless Internet-access mesh network (WIMNET) has been studied to realize the inexpensive, scalable Internet-access network by adopting multiple access points (APs) connected by wireless links. WIMNET can improve the dependability to failures of APs and/or links by allocating APs redundantly, whereas redundant APs may cause the increase of the operational cost and the degradation of the throughput due to increasing radio interferences. Therefore, we have formulated the active AP selection problem of selecting the minimum number of active APs among redundant APs in WIMNET and proposed its heuristic algorithm. The simulation results indicated the existence of an active AP selection maximizing the throughput whose number of active APs is larger than the minimum. In this paper, we improve this algorithm for the throughput maximization. We verify the effectiveness of our algorithm improvement through simulations in three instances.

An Improvement of Code Verifications in Java Programming Learning System Using Test-Driven Development Method

FUKUYAMA Yuki, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan, AMANO Noriki

IEICE technical report 111 ( 213 ) 13 - 18 2011.9

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

For the enhancement of the Java programming education by assisting self-studies of students and reducing loads of teachers, we have proposed and developed a Web-based Java programming learning system using the test-driven development method. In this system, the teacher first registers an exercise subject, a model source code, and a test code. Then, the student submits the test code and the answer code, which are verified by the verification tool at the server. Unfortunately, the current system cannot detect an incomplete test code from a student that does not contain necessary test procedures if it has no grammatical error. In this paper, we introduce a code coverage verification tool into the system in order to find an incomplete test code. After implementing this proposal, we evaluate the effectiveness of the improved system through experiments to 11 students who have studied Java.

An Implementation and Evaluation of Fixed Backoff-time Switching Method on QualNet for Wireless Mesh Network

SUKARIDHOTO Sritrusta, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan, TAJIMA Shigeto

IEICE technical report 111 ( 91 ) 33 - 38 2011.6

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

As an inexpensive and scalable access network to the Internet, we have studied the architecture, protocols, and design optimizations of Wireless Internet access Mesh Network (WIMNET). WIMNET is composed of multiple access points (APs) connected through wireless links. Previously, we have proposed the CSMA -based Fixed Backoff-time Switching (CSMA-FBS) method for WIMNET to improve the performance by giving necessary link activation chances for multi-hop communications. In this study, we implement the CSMA-FBS method on the QualNet simulator for evaluations in more realistic network environments. The simulation results in three network topologies confirm the effectiveness of our proposal.

A WDS Clustering Algorithm for Wireless Mesh Network with Gateway using MIMO Channel

TAJIMA Shigeto, FUNABIKI Nobuo, TOMISATO Shigeru, HATA Masaharu, HIGASHINO Teruo

IEICE technical report 111 ( 8 ) 55 - 60 2011.4

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

We have studied the Wireless Internet-access Mesh NETwork (WIMNET) as a scalable wireless local area network that is composed of multiple access points (APs) connected through the Wireless Distribution System (WDS). To avoid the performance degradation due to traffic overloads, the number of APs in a single WDS is limited. Hence, we have proposed a WDS clustering algorithm to partition a given set of APs into a disjoint set of WDS clusters where the APs in one WDS cluster shares a single gateway (GW) to the Internet and are connected by a single WDS. As all the traffics from/to the Internet pass through the GW in a WDS cluster, links incident to the GW can be bottlenecks of whole communications. In this paper, in order to increase the throughput there by adopting the MIMO channel at the GW, we propose an extension of the WDS clustering algorithm to the WIMNET with the MIMO channel GW. Through simulations using several instances, we verify the effectiveness of our algorithm extension.

An Implementation of an Online Fill-in-the-blank Problem Function for Learning Reserved Words in Java Programming

KORENAGA Yousuke, MATSUSHIMA Yukiko, FUNABIKI Nobuo, NAKANISHI Toru, AMANO Noriki

IEICE technical report 110 ( 453 ) 125 - 130 2011.2

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

The Java programming has been educated to students in a lot of universities and professional schools due to its reliability, portability, and easy learning. To assist the education, our group has developed a Java programming education assistant system based on the test-driven development method. However, this system targets students who have studied Java to some extent. In this paper, we propose the online fill-in-the-blank problem function for this Web system to assist the learning of the reserved words of Java for Java beginners. This function consists of the teacher service function and the student service function. By the former function, a teacher can generate a fill-in-the-blank problem automatically by removing the specified reserved words randomly from a sample Java code in the database. By the latter function, a student can repeatedly submit answers of a problem until all the answers are correct for self-study. The function is implemented at the existing system and is applied to students who are Java beginners, where the questionnaire result confirms the effectiveness of our proposal.

An Implementation of a Web-based Assistance System for Computer-Scored Tests

KAWANO Hiroki, FUNABIKI Nobuo, NAKANISHI Toru, AMANO Noriki

IEICE technical report 110 ( 453 ) 193 - 198 2011.2

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

Mini-exams and quizzes during classes can be effective to enhance their educational effects to students in universities. However, teachers may have to spend much time to prepare test materials before classes, and grade the test papers from students after them. In this paper, we propose a Web-based assistance system for computer-scored tests in order to reduce these loads by teachers. Our system consists of the question generation & management function, the test generation & management function, the subject generation & management function, the test grading function, and the learning history management function. By treating questions and tests separately such that one test is composed of individual questions, this system makes it possible to reuse existing questions and tests in various subjects by sharing them among teachers. Besides, by automatically generating test papers containing randomly shuffled options, it can prevent students from cheating by peeking at papers of other students at neighbor seats. To evaluate the efficiency, we implemented the system by extending the existing learning management system NOBASU, and applied it to one class in our department.

An Implementation of Menu Planning and Cooking Step Optimization Functions in a Web-based Homemade Cooking Assistance System for Busy Persons

OKADA Tomoya, MATUSHIMA Yukiko, TANIGUCHI Shiho, FUNABIKI Nobuo, NAKANISHI Toru

IEICE technical report 110 ( 453 ) 205 - 210 2011.2

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

For busy persons such as workers, students, and child-growing families, preparations of dishes by homemade cooking may become heavy burdens on weekdays. To solve this problem, our group has developed a Web-based homemade cooking assistance system composed of four main functions. In this paper, we implement the two functions of the menu planning and the cooking step optimization for this system. The first function helps a user to generate a menu manually, or automatically by using the menu selection algorithm. Besides, it allows the user to register the menu information into Google calendar so that the information can be accessed even from a mobile terminal. The second function optimizes the schedule of the cooking steps by using the cooking step optimization algorithm. By outputting the result into a PDF file, the user can use it at cooking. The effectiveness of these functions is confirmed through questionnaire results by 16 students in our department.

A Proposal of a Management System for Open Source Software Usage Manuals Using Content Management System

RI Denzai, MURAKAMI Yukikazu, FUNABIKI Nobuo

IEICE technical report 110 ( 453 ) 187 - 192 2011.2

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

Recently, the Open Source Software (OSS) has become used at many places. Even the installation and initial configuration of an OSS can be difficult for novice users, because there are few documents and manuals. To address this problem, we have proposed an automatic generation method of installation/configuration manuals for OSS However, this method has another problem of requiring different manuals even for the same OSS, because installation commands or configuration parameters can be different depending on OS distributions and OS/OSS versions. In this paper, we propose an OSS manual management system using a content management system "Joomla!" so that the manuals can be consolidated in a community. We implement the system composed of the four functions for general users, manual creators, community managers, and system managers, and show the effectiveness through usability evaluations using a questionnaire.

Development of an Automatic Generation System of Configuration Manuals for Open Source Software

KAGAWA Erina, MURAKAMI Yukikazu, FUNABIKI Nobuo

IEICE technical report 110 ( 448 ) 247 - 252 2011.2

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

Recently, Open Source Software (OSS) has become used at many places. However, the use of an OSS is hard for its novice users, because many OSSes have few good manuals. To solve this problem, we have proposed a method of automatically generating a web manual for installing an OSS by editing the log information recorded during the installation process by a skilled user. However, many OSS require to make changes the configuration file. In addition to that more systems are adopting OSS as middlewares such as application servers and DBMSs (Database Management Systems). For these OSS middlewares, it is known that even the processing performance is low under their default settings a great improvement is seen by optimizing their system setting. Therefore, in this research, aiming at accumulation of system optimizing technology, an automatic generation of web-based configuration manual is proposed.

An Application of the WEB Page Layout Optimization Method for Integration of Open Source Software Heterogeneous Manuals

HORI Yuki, MURAKAMI Yukikazu, FUNABIKI Nobuo

IEICE technical report 110 ( 448 ) 241 - 246 2011.2

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

Recently, the Open Source Software (OSS) has become used at many places. Even the installation and initial configuration of an OSS can be difficult for novice users, because there are few documents and manuals. To address this problem, we have proposed an automatic generation method of installation/configuration manuals for OSS. However, in the conventional system, an installation manual and a configuration manual are managed as an individual file. Therefore, the conventional system had bad convenience. We integrate an installation manual and a configuration manual and define this as an OSS usage manual. When integrate manuals, it is necessary to give a priority and to show information. When the size of a Web manual is changed by the user, a layout changes and visibility falls. In order to solve this problem, we applied to the web-page layout optimization method to proposed manuals.

A Proposal of Cooking Model and Cooking Step Scheduling Algorithm for Multiple Dishes

MATSUSHIMA Yukiko

IMECS 2011 127 - 131 2011

An active access-point selection approach for dependable wireless mesh networks

Nobuo Funabiki, Junki Shimizu, Masaharu Hata, Shigeru Tomisato, Toru Nakanishi, Kan Watanabe

Journal of Interconnection Networks 12 ( 3 ) 137 - 154 2011

Authorship：Lead author Language：English Publisher：World Scientific Publishing Co. Pte Ltd

As an inexpensive, flexible, and scalable Internet-access wireless network, we have studied the architecture, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET) that adopts multiple access-points (APs) connected through wireless links. WIMNET can improve the dependability to failures of APs and/or their links by allocating APs redundantly in the network field. Because redundant APs may increase the operational cost and degrade the throughput due to increasing radio interferences, only the necessary APs for connectivity between the hosts and the Internet gateway should be activated in communications. In this paper, we first define the active AP selection problem of selecting the minimum number of active APs, and prove the NP-completeness of its decision version through reduction from the known minimum set cover problem. Then, we propose an active AP selection algorithm of deactivating APs one by one until no more AP can be deactivated. Due to the limited transmission capacity in WIMNET, we further present an algorithm extension for throughput maximization. We verify the effectiveness of our proposal through simulations in three instances, where the number of active APs is reduced by more than 40% and the throughput is improved by more than 10% from the original in any instance. © 2011 World Scientific Publishing Company.

DOI： 10.1142/S0219265911002915

An implementation of fixed backoff-time switching method on IEEE 802.11 MAC protocol for wireless Internet-access mesh network

Nobuo Funabiki, Sritrusta Sukaridhoto, Zhe Wang, Toru Nakanishi, Kan Watanabe, Shigeto Tajima

The 2011 International Workshop on Smart Info-Media System in Asia (SISA 2011) 67 - 72 2011

A proposal of an active access-point selection algorithm in wireless mesh networks

Nobuo Funabiki, Junki Shimizu, Toru Nakanishi, Kan Watanabe

Proceedings - 2011 International Conference on Network-Based Information Systems, NBiS 2011 112 - 117 2011

Authorship：Lead author Language：English

The wireless Internet-access mesh network (WIMNET) has been studied to offer an inexpensive, scalable Internetaccess wireless network by adopting multiple access points (APs) connected by wireless links. WIMNET can improve the dependability to failures of links and/or APs by allocating APs redundantly in the network field. However, redundant APs may increase the operational cost and degrade the throughput due to increasing radio interferences. One solution to this problem is to activate only the necessary APs to provide the connectivity to the hosts while maximizing the throughput. In this paper, we first define this active AP selection problem of selecting the activated APs for communications, and propose its heuristic algorithm. The simulation results in three instances confirm the effectiveness of the proposed algorithm, and indicate the existence of an active AP selection that maximizes the throughput. Then, we present the average hop count and the traffic bias as the indices to seek the active AP selection with the maximal throughput, and the extension of our active AP selection algorithm using them. © 2011 IEEE.

DOI： 10.1109/NBiS.2011.26

A smart access-point selection algorithm for scalable wireless mesh networks

Nobuo Funabiki, Sritrusta Sukaridhoto, Masaharu Hata, Shigeru Tomisato, Toru Nakanishi, Kan Watanabe, Shigeto Tajima

IAENG International Journal of Computer Science 38 ( 3 ) 260 - 267 2011

Efficient Proofs of Attributes in Pairing-Based Anonymous Credential System

Amang Sudarsono, Toru Nakanishi, Nobuo Funabiki

PRIVACY ENHANCING TECHNOLOGIES 6794 246 - 263 2011

Language：English Publisher：SPRINGER-VERLAG BERLIN

An anonymous credential system allows the user to convince a verifier of the possession of a certificate issued by the issuing authority anonymously. One of the applications is the privacy-enhancing electronic ID (eID). A previously proposed anonymous credential system achieves constant complexity in the number of finite-set attributes of the user. However, the system is based on the RSA. In this paper, we show how to achieve the constant complexity in a pairing-based anonymous credential system excluding the RSA. The key idea of the construction is the use of a pairing-based accumulator. The accumulator outputs a constant-size value from a large set of input values. Using zero-knowledge proofs of pairing-based certificates and accumulators, we can prove AND and OR relations with constant complexity in the number of finite-set attributes.

DOI： 10.1007/978-3-642-22263-4_14

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