Faculty Profiles - FUNABIKI Nobuo

MISC - FUNABIKI Nobuo

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A Web Recipe Conversion Algorithm for Cooking-Step Scheduling

ZHANG Yijia, FUNABIKI Nobuo, NAKANISHI Toru

Technical report of IEICE. SS 113 ( 422 ) 11 - 16 2014.1

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

Previously, we have proposed the cooking-step scheduling algorithm to assist home-made cooking by busy people such as working persons and students. When a cooking-step schedule of applying the cooking procedures in recipes in a Web site is generated by this algorithm, their conversion into the unique input form to the algorithm is required. In this paper, we propose a Web-recipe conversion algorithm that converts cooking procedures in a recipe into six types of cooking-steps and estimates the corresponding cooking time by extracting keywords in the recipe that correspond to the cooking-step types. We verified the effectiveness of the proposed algorithm through applying it to 100 recipes.

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A Clue Function Using Javadoc for Code Writing Problem in Java Programming Learning Assistant System

NAKAMURA Takuya, FUNABIKI Nobuo, NAKANISHI Toru, AMANO Noriki

IEICE technical report. Education technology 113 ( 377 ) 115 - 120 2014.1

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 Javadoc-based hint function in the code design learning function of JPLAS to let such students learn how to collect the necessary information for a source code from a test code easily. It helps students to understand the whole structure of the source code and complete more accurate code design. We verify the effectiveness of our proposal through applications to 10 students in our laboratory.

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Implementation of Anonymous Credential System with Efficient Proofs for Monotone Formulas on Attributes Excluding Restriction

Shahidatul Sadiah, Toru Nakanishi, Nobuo Funabiki

2014 SECOND INTERNATIONAL SYMPOSIUM ON COMPUTING AND NETWORKING (CANDAR) 531 - 535 2014

Language：English Publisher：IEEE

An anonymous credential system allows a user to convince a service provider anonymously that he/she owns certified attributes. Previously, we proposed an anonymous credential system to prove user's attributes to satisfy a monotone formula, i.e., a logic relation with any combination of AND/OR relations. However, this system has a restriction that the user can prove the monotone formula when only one attribute is true for any OR relation. Recently, we proposed the improved system to overcome the restriction, by adopting Linear Homonorphic (LH) signature scheme to generate a certificate that contains the minimum attribute set as required in the verification. However, the improved system has never been implemented, and thus the practicality is not evaluated. In this paper, we implement the system using a fast pairing library, and measure the processing times and data sizes, when changing the number of user's attributes and the size of the proved relation.

DOI： 10.1109/CANDAR.2014.35

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A Proposal of Routing Algorithm under Practical Conditions for Wireless Internet-Access Mesh Networks

Nobuo Funabiki, Toru Nakanishi, Wataru Maruyama

2014 IEEE INTERNATIONAL CONFERENCE ON CONSUMER ELECTRONICS - TAIWAN (ICCE-TW) 27 - 28 2014

Authorship：Lead author Language：English Publisher：IEEE

A Wireless Internet-access Mesh NETwork (WIMNET) can provide an expandable Internet-access network by flexibly adopting multiple Access-Points (APs) that have wireless connections in the field. Previously, we proposed a routing algorithm for generating an optimal routing path between the hosts and one Internet Gateway (GW). However, in practical situations, multiple GWs are usually necessary for scalability. Beside, in the high-speed IEEE802.11ac protocol, the link speed drastically decreases as the distance increases due to the lowered receiving signal quality. Furthermore, commercial APs implementing them have the limitation on the number of hops between a GW and a host. In this paper, we propose a routing algorithm to consider these practical conditions for large-scale WIMNET. We verify the effectiveness through simulating three topologies using the WIMNET simulator.

DOI： 10.1109/ICCE-TW.2014.6904085

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Extensions of Active Access-Point Selection Algorithm for Wireless Mesh Networks Using IEEE802.11ac Protocol

Chang Choon Chew, Nobuo Funabiki, Sho Fujita

2014 SECOND INTERNATIONAL SYMPOSIUM ON COMPUTING AND NETWORKING (CANDAR) 310 - 314 2014

Language：English Publisher：IEEE

A wireless Internet-access mesh network (WIMNET) provides a scalable Internet-access network by flexibly allocating access points (APs) in the field that are connected by wireless links. Previously, we proposed an active AP selection algorithm to select the APs to be activated among the redundantly allocated APs for WIMNET that has a single Internet gateway (GW). However, in practical implementations of large-scale WIMNET, multiple GWs are usually necessary to increase the capacity of Internet connections. Besides, the number of hops between a GW and a host is limited for stable multihop communications, and the transmission speed of a wireless link is dynamically changed by the link condition such as the distance in the high-speed IEEE802.11ac protocol. Furthermore, the minimum throughput should be provided to a host as QoS (Quality of Service) when it is exclusively connected with the GW. In this paper, we propose extensions of the active AP selection algorithm to consider these conditions. We verify the effectiveness of our proposal through simulations in three topologies using the WIMNET simulator.

DOI： 10.1109/CANDAR.2014.29

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A Frame Aggregation Extension of Routing Algorithm for Wireless Mesh Networks

Nobuo Funabiki, Yuuma Tani, Shigeto Tajima

2014 SECOND INTERNATIONAL SYMPOSIUM ON COMPUTING AND NETWORKING (CANDAR) 238 - 242 2014

Authorship：Lead author Language：English Publisher：IEEE

As a scalable Internet-access network, an Wireless Internet-access Mesh NETwork (WIMNET) consists of multiple wireless access-points (APs) that are connected through wireless links. At least one AP acts as a gateway (GW) to the Internet where any host must reach there through multi-hop communications between APs. To handle large traffics, the latest highspeed IEEE 802.11ac protocol should be adopted for scalable WIMNET, where the routing path determines the performance under its practical implementations using commercial products. Therefore, we have proposed a routing algorithm considering 1) multiple GWs, 2) the link speed change, and 3) the limited number of hops. In this paper, to further improve the performance, we extend the routing algorithm to efficiently consider the frame aggregation in IEEE802.11ac. We verify the effectiveness of our proposal through simulating two topologies using the extended WIMNET simulator.

DOI： 10.1109/CANDAR.2014.28

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An extended active access-point selection algorithm for link speed changes in wireless mesh networks

International Journal Space-Based and Situated Computing 4 ( 3 ) 184 - 193 2014

A Proposal of Javadoc Hint Function for Java Programming Learning Assistant System

Nobuo Funabiki, Takuya Nakamura, Wen-Chung Kao

2014 IEEE 3RD GLOBAL CONFERENCE ON CONSUMER ELECTRONICS (GCCE) 304 - 308 2014

Authorship：Lead author Language：English Publisher：IEEE

As a reliable, portable, and practical programming language, Java has been educated in many universities and professional schools. To assist Java educations, we have developed a Web-based Java Programming Learning Assistant System (JPLAS) to help students studying Java programming by themselves through automatic testing of Java source codes using the test-driven development (TDD) method. Unfortunately, JPLAS is not suitable for novice students taking basic Java classes, because they need to extract necessary information such as the names of classes and methods from a test code for automatic testing before writing a source code. Previously, we implemented the code design learning function in JPLAS to assist such students. In this paper, we propose a Javadoc hint function in JPLAS to further assist students by showing the detailed information that is automatically generated from the reference code by a teacher for the assignment. We verify the effectiveness of our proposal through an experimental use by 41 students in our department.

DOI： 10.1109/GCCE.2014.7031127

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An Extension of Access-Point Allocation Algorithm for Adapting Link Speed Change in Wireless Mesh Network

FARAG Tamer, FUNABIKI Nobuo, HASSAN Walaa

IEICE technical report 113 ( 360 ) 137 - 142 2013.12

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

As an inexpensive, scalable Internet-access wireless network, we have studied design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET). WIMNET uses multiple access-points (APs) that are connected by wireless links. In WIMNET, the proper allocation of APs is essential to ensure the communication quality of hosts and to minimize the installation and management cost. Previously, we have proposed an AP allocation algorithm for WIMNET assuming that every link has a constant speed regardless of the condition. However, our preliminary experiments found that the link speed is greatly affected by the distance and interferences in high-speed IEEE802.11n/ac protocols that have recently become popular. In this paper, we propose an extension of our AP allocation algorithm to adapt to this link speed change where the maximum link distance between two APs that has been fixed in the previous algorithm is optimized to provide the highest performance. We verify the effectiveness of our extended algorithm through simulations in simple topology instances using the WIMNET simulator.

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A Proposal of Routing Tree Algorithm for Scalable Wireless Mesh Networks Under Practical Conditions

MARUYAMA Wataru, FUNABIKI Nobuo, NAKANISHI Toru

Technical report of IEICE. RCS 113 ( 361 ) 249 - 254 2013.12

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

As a flexible cost-efficient Internet access network, we have studied the Wireless Internet-access Mesh NETwork (WIMNET) that is composed of multiple access points (APs) connected through wireless links. We have proposed a routing tree algorithm to find a routing path between one Internet gateway (GW) and the hosts. However, normally, several GWs exist in practical implementations of WIMNET. The number of hops between a GW and a host is limited for commercial APs. Furthermore, the communication speed is dynamically changed by the link distance for the new high-speed communication protocol IEEE802.11ac. In this study, we propose a new routing tree algorithm considering these conditions for WIMNET. We verify the effectiveness of our proposal through simulating two instances using the WIMNET simulator.

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An Extension of Access-Point Allocation Algorithm for Adapting Link Speed Change in Wireless Mesh Network

FARAG Tamer, FUNABIKI Nobuo, HASSAN Walaa

Technical report of IEICE. RCS 113 ( 361 ) 255 - 260 2013.12

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

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Evaluation and Improvement of Credibility-based Voting for Volunteer Computing Systems with Dynamic Error Rate

2013 ( 26 ) 1 - 8 2013.12

An Implementation of Volunteer Computing System with Credibility-based voting

2013 ( 19 ) 1 - 7 2013.12

Efficient Proofs for CNF Formulas on Attributes in Pairing-Based Anonymous Credential System

Nasima Begum, Toru Nakanishi, Nobuo Funabiki

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E96A ( 12 ) 2422 - 2433 2013.12

Language：English Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

To enhance user privacy, anonymous credential systems allow the user to convince a verifier of the possession of a certificate issued by the issuing authority anonymously. In the systems, the user can prove relations on his/her attributes embedded into the certificate. Previously, a pairing-based anonymous credential system with constant-size proofs in the number of attributes of the user was proposed. This system supports the proofs of the inner product relations on attributes, and thus can handle the complex logical relations on attributes as the CNF and DNF formulas. However this system suffers from the computational cost: The proof generation needs exponentiations depending on the number of the literals in OR relations. In this paper, we propose a pairing-based anonymous credential system with the constant-size proofs for CNF formulas and the more efficient proof generation. In the proposed system, the proof generation needs only multiplications depending on the number of literals, and thus it is more efficient than the previously proposed system. The key of our construction is to use an extended accumulator, by which we can verify that multiple attributes are included in multiple sets, all at once. This leads to the verification of CNF formulas on attributes. Since the accumulator is mainly calculated by multiplications, we achieve the better computational costs.

DOI： 10.1587/transfun.E96.A.2422

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A Proposal of Extended Anonymous Credential Scheme with Efficient Proof of Age Inequality (Information Security)

SADIAH Shahidatul, NAKANISHI Toru, WATANABE Kan, FUNABIKI Nobuo

Technical report of IEICE. ISEC 113 ( 217 ) 21 - 28 2013.9

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

An anonymous credential system on attributes allows a user to convince a service provider anonymously that he/she owns a certified attribute. Previously, an anonymous credential system to prove that user attributes satisfy a CNF formula on attributes was proposed. However, the system needs a large public key (PK) size and thus the large computation times, when proving the age in equation using the birthday attribute, because each birthday is assigned to one attribute and each attribute is mapped to one public parameter. In this paper, to reduce the PK size and computation times, we use the idea of dividing the birthday (year/month/day) attribute into the year, the month, and the day attributes. Consequently, the PK size is decreased, since the number of attributes is reduced to approximately 0.3%. In case of proving the age in equation, these attributes have to be expressed using monotone logic formulas. To adopt this idea on previous system, we extend the accumulator in the previous system and we propose an anonymous credential system to prove monotonic formulas. Also, we show the effectiveness of proposed system by measuring the process times for the implementation.

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A Clustering Algorithm Considering Link Speed for Wireless Mesh Networks

TAJIMA Shigeto, FUNABIKI Nobuo, HIGASHINO Teruo

IEICE technical report 113 ( 129 ) 155 - 160 2013.7

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

A Wireless Internet-access Mesh Network (WIMNET) can provide a scalable Internet-access network by using multiple access point (APs) connected through wireless communications. In previous studies, we proposed a clustering algorithm for efficiently composing large scale WIMNET by partitioning the APs into a set of clusters. For this algorithm, we assume that any link has a constant speed, although our preliminary experiments found that the link speed is greatly changed by the link distance and interferences for the new high-speed IEEE802.11n protocol that has recently become popular. In this paper, we extend the clustering algorithm in considering the link speed change for effectively introducing IEEE802.11n to WIMNET. We verify the effectiveness of our proposal through simulations in grid topology instances using the WIMNET simulator.

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A Fixed Backoff-Time Switching Method for CSMA/CA Protocol in Wireless Mesh Networks

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

IEICE TRANSACTIONS ON COMMUNICATIONS E96B ( 4 ) 1019 - 1029 2013.4

Language：English Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

As a flexible and cost-efficient scalable Internet access network, we studied architectures, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET). WIMNET is composed of multiple access points (APs) connected through multihop wireless communications on IEEE 802.11 standards. The increasing popularity of real-time applications such as IF-phones and IP-TV means that they should be supported in WIMNET. 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. In this paper, we propose a 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. We implement our proposal on the QualNet simulator, and verify its effectiveness through simulations on three network topologies with four scenarios.

DOI： 10.1587/transcom.E96.B.1019

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BS-1-26 A Design for OpenFlow lmplementation of Fixed Backoff-time Switching Method in Wireless Mesh Networks

Sukaridhoto Sritrusta, Funabiki Nobuo, Nakanishi Toru, Watanabe Kan

Proceedings of the IEICE General Conference 2013 ( 2 ) "S - 50"-"S-51" 2013.3

D-9-27 AN EXPERIMENTAL EVALUATION OF COOKING-STEP SCHEDULING ALGORITHM IN COOKING FOUR DISHES

Matsushima Yukiko, Okada Tomoya, Funabiki Nobuo, Nakanishi Toru, Watanabe Kan

Proceedings of the IEICE General Conference 2013 ( 1 ) 125 - 125 2013.3

BS-1-2 AN IMPROVED HOST ASSOCIATION OPTIMIZATION STAGE IN ACCESS-POINT AGGREGATION ALGORITHM FOR WIRELESS LOCAL AREA NETWORKS

Islam Ezharul, Funabiki Nobuo, Nakanishi Toru, Watanabe Kan

Proceedings of the IEICE General Conference 2013 ( 2 ) "S - 3"-"S-4" 2013.3

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