Faculty Profiles - FUNABIKI Nobuo

MISC - FUNABIKI Nobuo

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A fixed backoff-time switching method for wireless mesh networks: Design and Linux implementation

Sritrusta Sukaridhoto, Nobuo Funabiki, Dadet Pramudihanto, Zainal Arief

Proceedings - 2013 International Conference on Information Technology and Electrical Engineering: "Intelligent and Green Technologies for Sustainable Development", ICITEE 2013 248 - 253 2013

Language：English Publisher：IEEE Computer Society

As a flexible and cost-efficient scalable Internet access network, we have studied architectures, protocols, and design optimizations of the Wireless Internet-Access Mesh NETwork (WIMNET). WIMNET is composed of wirelessly connected access points (APs), where any host can basically access to the Internet through multihop communications between APs with IEEE 802.11 standard. In WIMNET, undesirable situations can often happen such that some links dominate the bandwidth while others become insufficient due to the limited shared bandwidth. However, the contention resolution mechanism using a random backoff-time in the CSMA/CA protocol of 802.11 standards is not sufficient for handling real-time traffic in multihop wireless communications. Previously, we have proposed the concept of 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. We implemented our proposal on the QualNet simulator, and verify its effectiveness through simulations. In this paper, we present an implementation of the FBS method in Linux kernel to show its practicality and investigate the performance in a real network. Our design consists of implementations or modifications of the five programs: Kernel configuration, Debugfs, Minstrel, iw, and FBSdaemon. © 2013 IEEE.

DOI： 10.1109/ICITEED.2013.6676247

An access-point aggregation approach for energy-saving wireless local area networks

Md. Ezharul Islam, Nobuo Funabiki, Toru Nakanishi, Kan Watanabe

IEICE Transactions on Communications E96-B ( 12 ) 2986 - 2997 2013

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

Nowadays, with spreads of inexpensive small communication devices, a number of wireless local area networks (WLANs) have been deployed even in the same building for the Internet access services. Their wireless access-points (APs) are often independently installed and managed by different groups such as departments or laboratories in a university or a company. Then, a user host can access to multiple WLANs by detecting signals from their APs, which increases the energy consumption and the operational cost. It may also degrade the communication performance by increasing interferences. In this paper, we present an AP aggregation approach to solve these problems in multiple WLAN environments by aggregating deployed APs of different groups into limited ones using virtual APs. First, we formulate the AP aggregation problem as a combinatorial optimization problem and prove the NP-completeness of its decision problem. Then, we propose its heuristic algorithm composed of five phases. We verify the effectiveness through extensive simulations using the WIMNET simulator. Copyright © 2013 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1587/transcom.E96.B.2986

An Extension of Credibility Formula in Desktop Grid to Different Workers' Performance

2012 ( 16 ) 1 - 8 2012.12

A Web Service Implementation of ◆ Attribute Authentication

HAMADA Yuji, NAKANISHI Toru, WATANABE Kan, FUNABIKI Nobuo

IEICE technical report. Life intelligence and office information systems 112 ( 306 ) 41 - 46 2012.11

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

Our research group has proposed the anonymous authentication scheme using user's attributes. In this scheme, the user can anonymously convince a verifier of the possession of attributes specified by the service provider with the complexity independent of the number of attributes. Previously, we have implemented Web system where the user proves the AND relations to a verifier. However, we cannot prove CNF fomulas that is the conbination of AND and OR relations at our Web system. In this study, we implemented the anonymous attributes authentication system for CNF fomulas using proxies and a questionnaire service as a Web service. We measured the communication times including the authentication times. The results show that our system is sufficiently practical.

An Implementation of Anonymous Attributes Authentication System on Android Smart Phone

2012 ( 3 ) 146 - 152 2012.10

An Implementation of Reputation System with Secrecy Even for Administrators

2012 ( 3 ) 828 - 834 2012.10

An Extension of Wireless Internet-Access Mesh Network Simulator for Smart Antenna Use and Evaluations Using Simple Topologies

TAJIMA Shigeto, FUNABIKI Nobuo, HIGASHINO Teruo

IEICE technical report 112 ( 231 ) 125 - 130 2012.10

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

As an inexpensive, flexible, and scalable Internet-access network, we have studied architecture, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET). WIMNET consists of multiple access-points (APs) as wireless routers that are connected through wireless links. To improve the performance by realizing high-speed and simultaneous plural link communications, we have considered use of the smart antenna as a generalized technology of the Multiple-Input-Multiple-Output (MIMO) channel and the Adaptive Array Antenna (AAA). In this paper, we present an extension of the WIMNET simulator for the smart antenna use, which has been developed by our group to estimate the throughput in WIMNET. Through simulations in simple topologies, we investigate impacts of two smart antenna use methods and of interval changes between adjacent nodes including APs and hosts, into the performance of WIMNET.

An Implementation of Code Design Learning Function in Java Programming Learning Assistant System

NAKAMURA Takuya, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan, AMANO Noriki

IEICE technical report. Education technology 112 ( 224 ) 17 - 22 2012.9

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

Java has been educated in a lot of universities and professional schools due to the reliability, portability, and easy learning. To assist Java educations, our group has developed a Web-based Java Programming Learning Assistant System (JPLAS) that helps students to study Java programming by themselves through automatic testing of Java codes from students using the test-driven development method. Unfortunately, JPLAS is not suitable for less-experienced students in Java because they have to understand test codes that are necessary in automatic testing before writing source codes. In this paper, we propose a code design learning function in JPLAS to let such students learn how to collect the necessary information for a source code from a test code. A code design result from a student is automatically verified through comparisons with the corresponding model answer from a teacher. We verify the effectiveness of our proposal through applications to 24 students in our department.

A Linux Implementation Design of Fixed Backoff-time Switching Method for Wireless Mesh Networks

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

IEICE technical report 112 ( 208 ) 83 - 88 2012.9

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

As a flexible and cost-efficient scalable Intenet access network, we have studied architectures, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET). WIMNET is composed of wirelessly connected access points(APs), where any host can basically access to the Internet through multihop communications between APs.In WIMNET, undesirable situations can often happen such that some links dominate the bandwidth while others become insufficient due to the limited shared bandwidth. To improve the performance by avoiding them, controls of activation chances for wireless links depending on their traffics are effective. Thus, previously, we have proposed the Fixed Backoff-time Switching (FBS) method for the CSMA/CA protocol, and verified the effectiveness using the QualNet simulator. In this paper, we present an implementation design of the FBS method in Linux kemel to show its practicality and investigate the performance in a real network. Our design consists of implementations or modifications of the five programs:Kernel configuration, Debugfs,Minstrel,iw, and FBSdaemon.

BS-5-29 An Idea of Linux Implementation of Fixed Backoff-time Switching Method for Wireless Mesh Networks(BS-5. Network and Service Design, Control and Management)

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

Proceedings of the Society Conference of IEICE 2012 ( 2 ) "S - 82"-"S-83" 2012.8

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

As a flexible and cost-efficient scalable Internet access network, we have studied architectures,protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET). WIMNET is composed of wireless connected access points. Previously, we proposed the Fixed Backoff-time Switching (FBS) method for the CSMA/CA protocol to improve the real-time traffic performance in WIMNET by giving the necessary activation chances to each link, and verified the effectiveness using the QualNet simulator. In this paper, we present an idea of the FBS method implementation at Linux kernel after quickly reviewing it.

An Extension of Cooking-Step Scheduling Algorithm for Simultaneous Cooking of Multiple Dishes

MATSUSHIMA Yukiko, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan

IEICE technical report. Life intelligence and office information systems 112 ( 188 ) 1 - 6 2012.8

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

To assist homemade cooking of busy persons such as working people and child-growing families, we have proposed a cooking-step scheduling algorithm for multiple dishes. By composing the cooking procedure for each dish as a sequence of cooking-steps, this algorithm generates an optimal schedule of the cooking-steps for multiple dishes to minimize the cooking time while considering the constraints of cooks and instruments as a cooking model. In this paper, to enhance the practicality, we extend the algorithm in 1) accommodating the continuous cooking-steps such as boiling ingredients soon after stirring for a dish cooked by boiling or stewing, 2) suggesting the clearance chance of used instruments at a long waiting time, 3) preferentially assigning any possible cooking-step of the preferred dish to the sub-cook, and 4) considering the skill level of a cook in the operating time of a cooking-step. Through simulations and cooking experiments using five dishes, we verify the effectiveness of our algorithm extensions.

An Extension of Cooking-Step Scheduling Algorithm for Simultaneous Cooking of Multiple Dishes

MATSUSHIMA Yukiko, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan

IEICE technical report. Image engineering 112 ( 189 ) 1 - 6 2012.8

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

To assist homemade cooking of busy persons such as working people and child-growing families, we have proposed a cooking-step scheduling algorithm for multiple dishes. By composing the cooking procedure for each dish as a sequence of cooking-steps, this algorithm generates an optimal schedule of the cooking-steps for multiple dishes to minimize the cooking time while considering the constraints of cooks and instruments as a cooking model. In this paper, to enhance the practicality, we extend the algorithm in 1) accommodating the continuous cooking-steps such as boiling ingredients soon after stirring for a dish cooked by boiling or stewing, 2) suggesting the clearance chance of used instruments at a long waiting time, 3) preferentially assigning any possible cooking-step of the preferred dish to the sub-cook, and 4) considering the skill level of a cook in the operating time of a cooking-step. Through simulations and cooking experiments using five dishes, we verify the effectiveness of our algorithm extensions.

A Pairing-Based Anonymous Credential System with Efficient Attribute Proofs

Amang Sudarsono, Toru Nakanishi, Nobuo Funabiki

53 ( 6 ) 11p 2012.6

A Generalization of WDS Clustering Algorithm Extension to Smart-Antenna in Wireless Mesh Networks

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

IEICE technical report 112 ( 8 ) 37 - 42 2012.4

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

As a scalable inexpensive Internet-access network, we have studied the Wireless Internet-access Mesh Network (WIMNET) that is composed of multiple access point (APs) connected through the Wireless Distribution System (WDS). Because all the traffics pass through an Internet gateway (GW) in WIMNET, the resolution of link congestions around the GW is very important. For this problem, we have proposed a WDS clustering algorithm to partition the APs into a set of WDS clusters where the APs in each cluster shares an GW, and have considered the adoption of a smart antenna for a Smart AP (SAP). Since the smart antenna is usually expensive, we have extended the WDS clustering algorithm to a cluster where only one or two SAPs are used. In this paper, we generalize this extension to a cluster with an arbitrary number of SAPs. Besides, we investigate the priority action of the smart antenna for multiple SAPs in one cluster. We evaluate the effectiveness through simulations using grid topology instances.

BS-3-17 LOAD BALANCING STAGE FOR AN ACCESS-POINT AGGREGATION ALGORITHM IN WIRELESS LOCAL AREA NETWORKS(BS-3. Management and Control Technologies for Innovative Networks)

Islam Md. Ezharul, Funabiki Nobuo, Nakanishi Toru, Watanabe Kan

Proceedings of the IEICE General Conference 2012 ( 2 ) "S - 33"-"S-34" 2012.3

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

Currently, many organizations such as universities and companies are using multiple wireless local area networks (WLANs) even in the same building, where wireless access-points (APs) are independently managed by different groups such as departments or laboratories. As a result, a WLAN user host can detect signals from multiple APs, which may increase the interference and degrade the communication performance. Therefore, we have proposed an AP aggregation algorithm to minimize the number of active physical APs by aggregating the APs in the field by introducing virtual APs. In this paper, we introduce a load balancing stage to this algorithm to maximize the throughput by balancing loads among APs. The effectiveness has been verified through simulations in two instances.

An Extension of Web-based Assistance System for Computer-Scored Paper Tests

TAKAKI Shogo, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan, AMANO Noriki

IEICE technical report. Education technology 111 ( 473 ) 243 - 248 2012.3

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

A frequent application of mini-exams and quizzes during classes can be effective to enhance the educational effects to students in universities. However, teachers may have to spend much time to prepare the test papers before classes, and grade the test papers from students after them. In order to ease such burdens of teachers, we have proposed a Web-based assistance system for computer-scored paper tests in conventional lecture rooms without computers for students. This system supports the test paper generation, the test paper grading, and the score management. In this paper, we extend the system by adding two new question types, implementing the test paper preview function, and providing the data export function to the Web quiz function in an existing learning assistant system. We evaluate the effectiveness of our proposal through an experiment in one class in our department.

An Extension of Fill-in-the-blank Problem Function in Java Programming Learning Assistant System and Its Application to Class

KORENAGA Yousuke, FUNABIKI Nobuo, NAKANISHI Toru, WATANABE Kan, AMANO Noriki

IEICE technical report. Education technology 111 ( 473 ) 7 - 12 2012.3

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

The programming language Java has been educated in a lot of universities and professional schools due to the reliability, portability, and easy learning. To assist this Java education, our group has developed a Web-based Java Programming Learning Assistant System (JPLAS) by supporting self-studies of students. JPLAS has the fill-in-the-blank problem function for Java novice students to study Java reserved words. In this function, a teacher first generates fill-in-the-blank problems automatically by removing the specified reserved words randomly from a sample Java code in the database. Then, a student can repeatedly submit answers to the problems until all the answers are correct as self-studies. In this paper, we implement the score graph function so that the students can complete with each other in solving fill-in-the-blank problems by referring the current scores of other students. We apply the function to students in a Java programming class in our department to evaluate the effectiveness of our proposal.

An Implementation of Erroneous Code Indication Function in Java Programming Learning Assistant System Using Test-Driven Development Method

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

IEICE technical report. Education technology 111 ( 473 ) 1 - 6 2012.3

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

To enhance the effect of the Java programming education by assisting self-studies of students, we have proposed a Web-based Java Programming Learning Assistant System (JPLAS) using the test-driven development (TDD) method. In this system, a teacher first registers an exercise subject, a model source code, and a test code. Then, a student submits the answer code on the subject. The answer code is automatically verified by the verification tool at the server, and the verification result log is returned to the student. However, in the current system, even reading the log to find the errors is actually difficult for a student who is a Java programming beginner. In this paper, we implement an erroneous code indication function in JPLAS of graphically showing the error parts on the code. We evaluate the effectiveness of this function through an experiment to 42 students who are learning Java.

An Internship Instance of Developing an Assistance System for Promoting Group Events Using Ruby

OKADA Tomoya, KORENAGA Yousuke, HAMADA Yuji, IKEDA Daiki, SHIMIZU Junki, TAKEBAYASHI Tatuya, FUNABIKI Nobuo, NAKANISHI Toru, Ishihara HIROYUKI, SATOU Junyuki, OTORI Yoshinori, KOHMOTO Takayuki, OHTA Mayumi

IEICE technical report. Education technology 111 ( 394 ) 35 - 40 2012.1

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

The Graduate School of Natural Science and Technology in Okayama University has offered a special exercise class named "Internship in Engineering and Science" so that the students can experience practical works in companies through long term internships there. In the past two years, we have had the exercise at Systems Nakashima Co., Ltd. in developing a Web application system using Ruby for promoting events such as travels and parties in groups by helping the event planning, the attendance confirmation, and the schedule management. In this paper, we introduce the content of this exercise and the outline of the developed system. Besides, we describe the feedbacks of the students on this exercise.

Training Program for Practical Engineering Design through the Collaboration with Regional Companies

GOFUKU Akio, TABATA Nobuhisa, TOMITA Eiji, FUNABIKI Nobuo

Journal of Jsee 60 ( 1 ) 52 - 57 2012.1

Language：Japanese Publisher：Japanese Society for Engineering Education

An education program to bring up engineering design capabilities through long-term internship by the collaboration with regional companies has been put in practice for five years. The program is composed of two types of long-term internships and several lectures for patent systems and engineering ethics. This paper describes the outline of the program, educational effects, and our experiences. The program was improved into two educational programs in 2011. The one is a special course to educate engineers and scientists who can lead the technologies of their domains. The other is a long-term internship program for master students in engineering divisions of graduate school. This paper also describes the current activities of the latter program.

DOI： 10.4307/jsee.60.1_52

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