Faculty Profiles - FUNABIKI Nobuo

MISC - FUNABIKI Nobuo

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Accumulator for monotone formulas and its application to anonymous credential system

Shahidatul Sadiah, Toru Nakanishi, Nasima Begum, Nobuo Funabiki

Journal of Information Processing 25 949 - 961 2017.12

Authorship：Lead author Language：English Publisher：Information Processing Society of Japan

An anonymous credential system allows a user to convince a service provider anonymously that he/she owns certified attributes. Previously, a system to prove AND and OR relations simultaneously by CNF formulas was proposed. To achieve a constant-size proof of the formula, this system adopts an accumulator that compresses multiple attributes into a single value. However, this system has a problem: the proof generation requires a large amount of computational time in the case of lots of OR literals in the formula. Therefore, we convert the attribute relation from the CNF formula to a monotone formula to decrease the number of OR literals. The monotone formula is a logic formula that contains any combination of AND and OR relations. In this paper, we propose an extended accumulator to prove the monotone formula, and apply it to the anonymous credential system. Our approach to prove the monotone formula is that the tag assignment in the accumulator is extended to be adapted to the tree expressing the monotone formula. Using this type of formula, the number of public parameters multiplied in the accumulator is decreased, which greatly impacts the reduction of authentication time.

DOI： 10.2197/ipsjjip.25.949

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A Study of Throughput Estimation Model and Channel Assignment Algorithm for Partially Overlapping Channels in IEEE 802.11n Wireless Local-Area Networks (ネットワークシステム)

イスマエル・ムネネクエンガ, 舩曵信生, セリム・アル・マムンムハマド, ソウ・ルインキョウ, クマル・デブナシュモン

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117 ( 303 ) 23 - 28 2017.11

A Study of Throughput Estimation Model for IEEE 802.11n MIMO Link in Wireless Local-Area Network (ネットワークシステム) Reviewed

クマル・デブナシュモン, 舩曵信生, ソウ・ルインキョウ, セリム・アル・マムンムハマド

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117 ( 303 ) 17 - 22 2017.11

A Study of DCT-OFDM-Based Watermarking Scheme Assisted by Error Correcting Code

重本章吾, 栗林稔, 舩曵信生

電子情報通信学会技術研究報告 117 ( 282(EMM2017 55-65) ) 47 - 52 2017.11

A study of obfuscation for the security enhancement of watermarking schemes

山下晃一郎, 栗林稔, 舩曵信生

電子情報通信学会技術研究報告 117 ( 282(EMM2017 55-65) ) 53 - 58 2017.11

Making of Code Clone Elimination Problem Function for Java Programming Learning Assistant System

石原信也, 舩曵信生, 栗林稔

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117 ( 249 ) 25 - 30 2017.10

An Informative Test Code Approach for Code Writing Problem in Java Programming Learning Assistant System (ソフトウェアサイエンス)

キンゾウキン, 舩曵信生

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117 ( 248 ) 31 - 36 2017.10

An Informative Test Code Approach for Code Writing Problem in Java Programming Learning Assistant System (ディペンダブルコンピューティング)

キンゾウキン, 舩曵信生

電子情報通信学会技術研究報告 = IEICE technical report : 信学技報 117 ( 249 ) 31 - 36 2017.10

A software architecture for Java programming learning assistant system

Ishihara Nobuya, Funabiki Nobuo, Kuribayashi Minoru, Kao Wen-Chung

International Journal of Computer & Software Engineering 2 ( 1 ) 116 - 116 2017.7

Language：English Publisher：Graphy Publications

For advancements of Java programming educations, we have developed a Web-based Java Programming Learning System (JPLAS). JPLAS provides four problems with different levels, namely, element fill-inblank problem, value trace problem, statement fill-in-blank problem, and code writing problem, to cover students at different learning stages. Unfortunately, since JPLAS has been implemented by a number of students who studied in our group at different years, the code has become complex and redundant, which makes further extensions of JPLAS extremely hard. In this paper, we propose a software architecture for JPLAS to avoid redundancy. Based on the MVC model, our proposal uses Java for the model (M), HTML/CSS/JavaScript for the view (V), and JSP for the controller (C). Besides, adopting a design pattern, the marking functions of the four problems are implemented uniformly. For evaluations, after JPLAS is implemented with this architecture, the number of code files is compared with that of the previous implementation, and the number of additional files is examined for two new functions.

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An offline answering function for code writing problem in Java Programming Learning Assistant System

Nobuo Funabiki, Yingxin Wang, Nobuya Ishihara, Wen-Chung Kao

2017 IEEE International Conference on Consumer Electronics - Taiwan, ICCE-TW 2017 241 - 242 2017.7

Authorship：Lead author Language：English Publisher：Institute of Electrical and Electronics Engineers Inc.

In order to promote Java programming educations, the Web-based Java Programming Learning Assistant System (JPLAS) has been implemented. JPLAS provides the code writing problem, where students write Java codes that satisfy the given specifications and submit them to the JPLAS server to obtain the marks using test codes instantly. Unfortunately, JPLAS could be accessed simply when the Internet connections are available. In this study, we perform the offline answering function for the code writing problem for use of JPLAS even in places without the Internet connections. First, the teacher downloads the assignment files from the server and delivers them to the students using USB memories. Next, students solve the assignments on Eclipse including code writing and testing, then submit the results to the teacher. Finally, the teacher uploads the results to the server. To evaluate the proposed function, the questionnaire will be collected after giving five assignments to six students in our group.

DOI： 10.1109/ICCE-China.2017.7991085

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Watermarking Scheme with Large Capacity Considering the Internal Structure of PDF File

福島拓哉, 栗林稔, 舩曵信生

電子情報通信学会技術研究報告 117 ( 39(IT2017 1-15) ) 13 - 18 2017.5

A Proposal of Fingerprinting System for Protection of Sensitive Data from Internal Leakage

上田貴大, 栗林稔, 舩曵信生

電子情報通信学会技術研究報告 117 ( 39(IT2017 1-15) ) 19 - 24 2017.5

DCT-OFDM Watermarking Scheme Based on Communication System Model

Minoru Kuribayashi, Shogo Shigemoto, Nobuo Funabiki

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES E100A ( 4 ) 944 - 952 2017.4

Authorship：Lead author Language：English Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG

In conventional spread spectrum (SS) watermarking schemes, random sequences are used for the modulation of watermark information. However, because of the mutual interference among those sequences, it requires complicated removal operation to improve the performance. In this paper, we propose an efficient spread spectrum watermarking scheme by introducing the orthogonal frequency divisiion multiplexing (OFDM) technique at the modulation of watermark information. The SS sequences in the proposed method are the DCT basic vectors modulated by a pseudo-random number (PN) sequence. We investigate the SS-based method considering the host interference at the blind detection scenario and analyze the noise caused by attacks. Because every operation is invertible, the quantization index modulation (QIM)-based method is applicable for the OFDM modulated signals. We also consider the property of watermark extracting operation in SS-based and QIM-based method and formalize their models of noisy channel in order to employ an error correcting code. The performance of their methods with error correcting code is numerically evaluated under the constraints of same distortion level in watermarked content. The experimental results indicated a criteria for the selection of SS-based and QIM-based methods for given content, which is determined by the amount of host interference. In case that the host interference is 0.8 times smaller than a watermark signal, the SS-based method is suitable. When it is 1.0 times larger, the QIM-based method should be selected.

DOI： 10.1587/transfun.E100.A.944

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A Consideration of Partial Channel Interference in Channel Assignment for Holding Access-Point Assignment Problem in Wireless Local-Area Networks

116 ( 484 ) 457 - 462 2017.3

Cross-layer selective routing for cost and delay minimization in IEEE 802.11ac wireless mesh network

I. W. Lai, Nobuo Funabiki, Shigeto Tajima, Md. Selim Al Mamun, Sho Fujita

Wireless Networks 1 - 13 2017.2

Language：English Publisher：Springer New York LLC

A Wireless Internet-access Mesh NETwork (WIMNET) provides scalable and reliable internet access through the deployment of multiple access points (APs) and gateways (GWs). In this work, we propose a selective routing algorithm aiming at a hierarchical minimization of the operational cost and the maximal end-to-end delay. In particular, by deploying redundant APs/GWs in the network field, the WIMNET becomes robust to the link or AP/GW failure. However, these redundant APs/GWs increase the operational cost like the power consumption. By using Dijkstra algorithm and 2-opt algorithm, the proposed algorithm iteratively deactivates the deployed APs/GWs and performs the routing that reduces the maximal end-to-end delay based on the APs/GWs remaining active. The generated route meets the real-world constraints like fairness criterion. We further propose a cross-layer design to enhance the routing performance by exploiting the MAC-layer frame aggregation technique. The selective routing algorithm is then implemented in the WIMNET simulator proposed by our group. The numerical experiments demonstrate that in both indoor and open space environments, the proposed selective routing greatly reduces the operational cost, i.e., up to (Formula presented.) APs/GWs can be deactivated.

DOI： 10.1007/s11276-017-1462-9

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Cross-layer selective routing for cost and delay minimization in IEEE 802.11ac wireless mesh network

I. W. Lai, Nobuo Funabiki, Shigeto Tajima, Md. Selim Al Mamun, Sho Fujita

Wireless Networks 1 - 13 2017.2

Language：English Publisher：Springer New York LLC

DOI： 10.1007/s11276-017-1462-9

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A Proposal of Code Clone Deletion Problem for Java Programming Learning Assistant System

石原信也, 舩曵信生, 栗林稔