掲載種別：研究論文（学術雑誌）  

In a lot of universities across the world, C programming is taught to novice students in the first programming course. To assist their self-studies, we have developed C programming learning assistant system (CPLAS) that offers various programming problems with different learning goals where any answer from a student is automatically marked at the system. In this paper, we studied the phrase fill-in-blank problem (PFP) in CPLAS for learning basic C programming. A PFP instance gives a source code where several key phrases (set of elements) are blanked and requests to fill in them by a student. The correctness of answers is checked through string matching with the original ones. For evaluations, we generated 22 PFP instances for learning basic grammar topics and logic functions and assigned them with previous 15 instances for recursive functions to 21 students in Okayama University. The results confirmed the correctness of the generated instances and found the weakness of students in C programming study.

DOI： 10.18178/ijiet.2023.13.9.1948

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掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/s23146367

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掲載種別：研究論文（学術雑誌）  

Nowadays, the Internet of Things (IoT) has become widely used at various places and for various applications. To facilitate this trend, we have developed the IoT application server platform called SEMAR (Smart Environmental Monitoring and Analytical in Real-Time), which offers standard features for collecting, displaying, and analyzing sensor data. An edge device is usually installed to connect sensors with the server, where the interface configuration, the data processing, the communication protocol, and the transmission interval need to be defined by the user. In this paper, we proposed an edge device framework for SEMAR to remotely optimize the edge device utilization with three phases. In the initialization phase, it automatically downloads the configuration file to the device through HTTP communications. In the service phase, it converts data from various sensors into the standard data format and sends it to the server periodically. In the update phase, it remotely updates the configuration through MQTT communications. For evaluations, we applied the proposal to the fingerprint-based indoor localization system (FILS15.4) and the data logging system. The results confirm the effectiveness in utilizing SEMAR to develop IoT application systems.

DOI： 10.3390/info14060312

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掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/signals4020015

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掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/a16010045

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掲載種別：研究論文（国際会議プロシーディングス）  

Nowadays, Java programming is used in a variety of application systems as a highly portable object-oriented programming language. To assist its self-studies by novice students, we have developed the Java programming learning assistant system (JPLAS), and implemented the personal answer platform on Node.js. JPLAS offers several types of exercise problems at different learning levels, including the grammar-concept understanding problem (GUP), the value trace problem (VTP), the mistake correction problem (MCP), the element fill-in-blank problem (EFP), the code completion problem (CCP), and the phase fill-in-blank problem (PFP). Any answer is automatically marked by string matching with the correct one on the platform. In this paper, we present an implementation of the six problem types in a Java programming course in Okayama University. We generated 109 problem instances by following its curriculum and assigned them to 58 third-year students as homework before the final examination. Their solution results reveal the difficulty difference among the problem types and confirm the validity in the Java programming course.

DOI： 10.1109/ICIET56899.2023.10111422

Scopus

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掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/ICCE-Taiwan58799.2023.10226698

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その他リンク： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2023.html#LuFUK23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1145/3617733.3617736

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その他リンク： https://dblp.uni-trier.de/db/conf/icccm/icccm2023.html#LuFUK23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315417

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#PandumanFS23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315422

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#ZhangKHFH23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315351

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#KongZFHKH23

掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/info14070359

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掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/info14060300

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掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1145/3628454.3631856

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その他リンク： https://dblp.uni-trier.de/db/conf/iait/iait2023.html#LuFWAMK23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315512

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#NaingFWA23

掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315607

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#AnggrainiXFHSF23

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：MDPI AG  

Nowadays, the IEEE 802.11 wireless local area network (WLAN) has been widely used for Internet access services around the world. Then, the unfairness or insufficiency in meeting the throughput request can appear among concurrently communicating hosts with the same access point (AP), which should be solved by sacrificing advantageous hosts. Previously, we studied the fairness control method by adopting packet transmission delay at the AP. However, it suffers from slow convergence and may not satisfy different throughput requests among hosts. In this paper, we propose a throughput request satisfaction method for providing fair or different throughput requests when multiple hosts are concurrently communicating with a single AP. To meet the throughput request, the method (1) measures the single and concurrent throughput for each host, (2) calculates the channel occupying time from them, (3) derives the target throughput to achieve the given throughput request, and (4) controls the traffic by applying traffic shaping at the AP. For evaluations, we implemented the proposal in the WLAN testbed system with one Raspberry Pi AP and up to five hosts, and conducted extensive experiments in five scenarios with different throughput requests. The results confirmed the effectiveness of our proposal.

DOI： 10.3390/s22228823

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担当区分：責任著者   記述言語：英語  

掲載種別：研究論文（学術雑誌）  

—Currently, C programming is taught as the first programming language in many universities around the world due to the easy-to-learn and middle-level nature. However, the confusing concepts of keywords and unfamiliar formality make it difficult for students to study. Therefore, we have previously developed C programming learning assistance system (CPLAS) for self-studies of novice students. CPLAS offers several types of exercise problems with the automatic answer marking by string matching. In this paper, we propose a mistake correction problem (MCP) for code debugging study as a new problem type in CPLAS. MCP requests to answer every mistaken element and its correction in a given corrupt source code. We list up reserved words and common library functions in C programming for candidates of mistaken elements, and implement the MCP instance generation algorithm. To help solving MCP instances by a student, we implement the answer interface that shows the line number of each mistake, the corrupt code and answer forms in parallel, and the hint of suggesting the first character of each answer. For evaluations of the proposal, we generate 20 instances with 91 mistakes for basic grammars, and assign them to 18 university students in Japan, China, and Indonesia. Their answer results confirm the effectiveness of MCP.

DOI： 10.18178/ijiet.2022.12.11.1733

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掲載種別：研究論文（学術雑誌）  

At present, web-client programming using HTML, CSS, and JavaScript is essential in web application systems to offer dynamic behaviors in web pages. With rich libraries and short coding features, it becomes common in developing user interfaces. However, the teaching course is not common in universities due to limited time. Therefore, self-study tools are strongly desired to promote it in societies. Previously, we have studied the programming learning assistant system (PLAS) as a programming self-study platform. In PLAS, among several types of programming problems, the element fill-in-blank problem (EFP) has been implemented for code understanding study of C and Java programming. In an EFP instance, the blank elements in a source code should be filled in with the proper words, where the correctness is checked by string matching. In this paper, we implement EFP for web-client programming in PLAS. In a web page, HTML and CSS define the components with tags in the document object model (DOM), and JavaScript offers their dynamic changes with libraries, which are blanked in EFP. Besides, a set of web page screenshots are given to help the solution. For evaluations, the generated 21 EFP instances were assigned to 20 master students in Okayama University. By analyzing their solution results, the effectiveness was confirmed for JavaScript programming learning.

DOI： 10.18178/ijiet.2022.12.11.1736

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語  

掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/s22176436

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語  

担当区分：責任著者   記述言語：英語  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754790

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#PuspitaningayuF22

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754807

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#HtetFKZSAK22

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754593

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#LuCFKU22

掲載種別：研究論文（学術雑誌）  

DOI： 10.3390/info13050211

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754593

その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#LuCFKU22

掲載種別：研究論文（学術雑誌）  

DOI： 10.12720/jcm.17.8.592-599

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掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1007/978-3-031-14463-9_16

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その他リンク： https://dblp.uni-trier.de/db/conf/cdmake/cdmake2022.html#KuribayashiKF22

掲載種別：研究論文（学術雑誌）  

DOI： 10.4018/ijmcmc.301275

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掲載種別：研究論文（学術雑誌）  

C programming is taught in introductory programming courses in many universities across the world. To assist self-studies of novice students, we have developed C programming learning assistant system (CPLAS). In this paper, we study the grammar-concept understanding problem (GUP) in CPLAS for first-step studies of understanding grammar concepts in C programming. Each question describes the definition of a keyword in a source code and requests to answer it. Any answer is verified through string matching. If a student cannot answer questions, he/she does not understand basic concepts and may be lost in C programming study. For GUP, we selected 66 keywords with questions, and generated 35 instances that cover them. The assignment results to 130 undergraduate students in Okayama and Nihon Universities revealed the difficult keywords and learning progresses of students.

DOI： 10.3169/mta.10.198

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掲載種別：研究論文（国際会議プロシーディングス）  

To assist self-studies of C programming at home by novice students, we have studied the grammar-concept under-standing problem (GUP), the value trace problem (VTP), and the phase fill-in-blank problem (PFP) as introductory programming exercise problems. A GUP instance asks the keyword in a given source code that corresponds to the grammar concept described in the question. A VTP instance asks the value of an important variable or message in the code. A PFP instance asks a set of elements or a message to be filled in for each blank in the code. In any instance, the correctness of an answer is marked through string matching with the correct one. In this paper, we present a study of three introductory problems to novice students. We generated GUP/VTP/PFP instances by following the C programming course curriculum in Nihon University, Japan, and assigned them to its first-year undergraduate students who solved them at home for the course review before the final examination. The solution results reveal difficulty differences among the three introductory problems and three student groups in terms of solution performances.

DOI： 10.1109/ICIET55102.2022.9778953

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記述言語：英語   出版者・発行元：The Institute of Image Information and Television Engineers  

C programming is taught in introductory programming courses in many universities across the world. To assist self-studies of novice students, we have developed C programming learning assistant system (CPLAS). In this paper, we study the grammar-concept understanding problem (GUP) in CPLAS for first-step studies of understanding grammar concepts in C programming. Each question describes the definition of a keyword in a source code and requests to answer it. Any answer is verified through string matching. If a student cannot answer questions, he/she does not understand basic concepts and may be lost in C programming study. For GUP, we selected 66 keywords with questions, and generated 35 instances that cover them. The assignment results to 130 undergraduate students in Okayama and Nihon Universities revealed the difficult keywords and learning progresses of students.

DOI： 10.3169/mta.10.198

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

An effective way to defend against adversarial examples (AEs), which are used, for example, to attack applications such as face recognition, is to detect in advance whether an input image is an AE. Some AE defense methods focus on the response characteristics of image classifiers when denoising filters are applied to the input image. However, several filters are required, which results in a large amount of computation. Because JPEG compression of AEs effectively removes adversarial perturbations, the difference between the image before and after JPEG compression should be highly correlated with the perturbations. However, the difference should not be completely consistent with adversarial perturbations. We have developed a filtering operation that modulates this difference by varying their magnitude and positive/negative sign and adding them to an image so that adversarial perturbations can be effectively removed. We consider that adversarial perturbations that could not be removed by simply applying JPEG compression can be removed by modulating this difference. Furthermore, applying a resizing process to the image after adding these distortions enables us to remove perturbations that could not be removed otherwise. The filtering operation will successfully remove the adversarial noise and reconstruct the corrected samples from AEs. We also consider a simple but effective reconstruction method based on the filtering operations. Experiments in which the adversarial attack used was not known to the detector demonstrated that the proposed method could achieve better performance in terms of accuracy with reasonable computational complexity. In addition, the percentage of correct classification results after applying the proposed filter for non-targeted attacks was higher than that of JPEG compression and scaling. These results suggest that the proposed method effectively removes adversarial perturbations and is an effective filter for detecting AEs.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Advances in machine learning technologies, such as convolutional neural networks, have helped identify individuals using face recognition and identification techniques. A system can be constructed to detect the presence of specific features in an object. However, if the technologies are abused, individuals can be tracked automatically and their privacy would be violated. Therefore, it is necessary to develop a technique for avoiding automated human tracking systems that use facial identification. Conventional methods study adversarial noise to avoid recognition and face identification. However, they do not investigate the geometrical changes in the patch area. Here, we compared the performance of a non-transparent patch with that of a transparent patch and proposed a method for improving robustness against changes in position. Our experiments demonstrated that the non-transparent patch does not significantly affect the success rate of a face-identification system. The proposed method improves robustness against changes in the patch position.

Web of Science

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/CANDARW53999.2021.00051

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その他リンク： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021w.html#KamoyedjiFHK21

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/GCCE59613.2023.10315660

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#MonQWFK23

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/GCCE53005.2021.9621949

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その他リンク： https://dblp.uni-trier.de/db/conf/gcce/gcce2021.html#LuQFAHLK21

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Emerald  

<sec>
<title content-type="abstract-subheading">Purpose</title>
This study aims to present the value trace problem (VTP) for Python programming self-study, by extending the works for Java programming learning assistant system. In total, 130 VTP instances are generated using Python codes in textbooks and websites that cover basic/advanced grammar topics, fundamental data structures and algorithms and two common library usages. Besides, assisting references on Python programming topics related to the VTP instances are introduced to assist novice learners in solving them efficiently.


</sec>
<sec>
<title content-type="abstract-subheading">Design/methodology/approach</title>
PyPLAS offers the VTP to study grammar topics and library usage through code reading. A VTP instance asks a learner to trace the actual values of important variables or output messages in the given source code. The correctness of any answer is checked through string matching.


</sec>
<sec>
<title content-type="abstract-subheading">Findings</title>
The applications to 48 undergraduate students in Myanmar and Indonesia confirm the validity of the proposal in Python programming self-studies by novice learners.


</sec>
<sec>
<title content-type="abstract-subheading">Originality/value</title>
The applications to 48 undergraduate students in Myanmar and Indonesia confirm the validity of the proposal in Python programming self-studies by novice learners.


</sec>

DOI： 10.1108/ijwis-03-2021-0025

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その他リンク： https://www.emerald.com/insight/content/doi/10.1108/IJWIS-03-2021-0025/full/html

担当区分：筆頭著者,　責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/ICCE-TW52618.2021.9603085

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その他リンク： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#FunabikiLSHKUK21

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/ICCE-TW52618.2021.9603037

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その他リンク： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#PuspitaningayuF21

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：NEWSWOOD LTD  

Currently, Android smartphones have dominated the distribution of mobile devices around the world. Then, with high demands for Android programming jobs, large numbers of schools, universities, and professional training institutions offer related courses. The Android Programming Learning Assistance System (APLAS) has been developed to accommodate independent and automatic assisting learning for students to learn Android programming by adopting test-driven development (TDD) method. APLAS offers learning materials to systematically study Android programming through solving topics with four stages and provides features for automatic validation of the student's answers by running given test codes. However, a platform to support various activities of teachers for handling a lot of students in the courses is not implemented yet, and it made their load become very high. This paper presents the proposal of online platform in APLAS for distributing the learning materials, collecting the student's answers, and validating them, based on a web application system. By using Gradle, a validator program was developed for running the test codes automatically in the server when a new answer is submitted. A comprehensive evaluation has been applied by asking 60 undergraduate students in an Indonesian university to use the online platform, solve three APLAS learning topics, and submit the answers. The results showed that the three functions worked properly, and the validation process of 183 submissions from all students delivered correct results on the server. The stability, robustness, effectiveness, performance, and security of the online platform were confirmed by analyzing the data of users' activities and validation results. The significant reduction in processing time on all three functions also confirmed its effectiveness and improvement. Finally, the students' feedback proved its usability.

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ACM  

DOI： 10.1145/3479162.3479176

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その他リンク： https://dblp.uni-trier.de/db/conf/icccm/icccm2021.html#HtetFKZK21

担当区分：責任著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER INTERNATIONAL PUBLISHING AG  

Currently, the IEEE 802.11n wireless local-area network (WLAN) has been broadly deployed world-wide for flexible and high-speed Internet access communications. Since it uses the limited number of partially overlapping channels (POCs) at 2.4 GHz band, the throughput performance is often degraded by interferences from signals of other WLANs. Thus, we have studied throughput drop estimation models for concurrently communicating multiple links under interferences, where the 40 MHz channel bonding (CB) and 20 MHz non-CB are considered separately. We have observed that the simultaneous use of CB and non-CB can improve the performance by enhancing the channel capacity while reducing the interference. In this paper, we study the throughput drop estimation model for concurrently communicating links under coexistence of CB and non-CB in IEEE 802.11n WLAN. The model accuracy is verified by comparing the estimated throughput with the measured one under various network topologies.

DOI： 10.1007/978-3-030-79725-6_71

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

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その他リンク： https://dblp.uni-trier.de/db/journals/ieicetd/ieicetd104.html#MuneneFBRAKK21

掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

DOI： 10.1007/s42979-021-00580-1

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その他リンク： http://link.springer.com/article/10.1007/s42979-021-00580-1/fulltext.html

担当区分：責任著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Emerald  

<sec>
<title content-type="abstract-subheading">Purpose</title>
To advance Java programming educations, the authors have developed a Web-based Java programming learning assistant system (JPLAS). It offers the element fill-in-blank problem (EFP) for novice students to study Java grammar and basic programming skills by filling in the missing elements in a source code. An EFP instance can be generated by selecting an appropriate code, and applying the blank element selection algorithm. As it is expected to cover broad grammar topics, a number of EFP instances have been generated. This paper aims to propose a recommendation function to guide a student solving the proper EFP instances among them.


</sec>
<sec>
<title content-type="abstract-subheading">Design/methodology/approach</title>
This function considers the difficulty level of the EFP instance and the grammar topics that have been correctly answered by the student, and is implemented at the offline answering function of JPLAS using JavaScript so that students can use it even without the Internet connections.


</sec>
<sec>
<title content-type="abstract-subheading">Findings</title>
To evaluate the effectiveness of the proposal, 85 EFP instances are prepared to cover various grammar topics, and are assigned to a total of 92 students in two universities in Myanmar and Indonesia to solve them using the recommendation function. Their solution results confirmed the effectiveness of the proposal.


</sec>
<sec>
<title content-type="abstract-subheading">Originality/value</title>
The concept of the difficulty level for an EFP instance is newly defined for the proper recommendation, and the accuracy in terms of the average numbers of answer submission times among the students is verified.


</sec>

DOI： 10.1108/ijwis-11-2020-0070

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その他リンク： https://www.emerald.com/insight/content/doi/10.1108/IJWIS-11-2020-0070/full/html

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

C programming has been the fundamental subject to a lot of university students for studying programming languages, algorithms, and computer architecture. Currently, we are developing C programming learning assistant system (CPLAS) for its self-study by extending our works of JPLAS for Java programming. JPLAS provides the code completion problem (CCP) to offer practical programming exercises. A CCP instance asks the completion of the given source code by filling in the missing elements. The correctness of the answer is marked through string matching by comparing each answer statement with the correct one. In this paper, we present the CCP by extending our works of the element fill-in-blank problem (EFP) in CPLAS. For evaluations, we generated 10 CCP instances and assigned them to 54 undergraduate students in Myanmar and Japan. Their solution results show that the CCP instances are generally suitable for C programming study by novice students, but those on pointer need improvements for better solutions.

DOI： 10.1109/ICIET51873.2021.9419621

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391784

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#LuFKAD21

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391812

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#LuAKFAS21

担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

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その他リンク： https://dblp.uni-trier.de/db/journals/ijnc/ijnc11.html#BriantoroFRMKK21

掲載種別：研究論文（学術雑誌）  

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その他リンク： https://dblp.uni-trier.de/db/journals/corr/corr2107.html#abs-2107-02961

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391894

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その他リンク： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#KyawFK21

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ACM  

DOI： 10.1145/3437880.3460402

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その他リンク： https://dblp.uni-trier.de/db/conf/ih/ihmmsec2021.html#KuribayashiTSYF21

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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その他リンク： https://dblp.uni-trier.de/rec/conf/apsipa/2021

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

Photographs taken by smartphones and camera devices are generally compressed using JPEG by default when they are saved. If such an image is edited, it is decompressed and processed, and then recompressed through JPEG. Therefore, an edited image must be compressed by JPEG more than once. Using this characteristic, a forensic technique has been studied to detect image tampering by detecting distortions caused by double compression. In our previous study, to analyze the JPEG compression history using a convolutional neural network and (CNN), we observed a histogram calculated from the low-frequency components in 8 x 8 sized blocks of images having a pixel resolution of 512 x 512. However, there have been no detailed considerations regarding the range of observed histograms or the selection of DCT coefficients used to extract the features from a given image. In this study, we first examine the range of histograms to measure the usefulness of the classification of double JPEG-compressed images, and then examine the classification accuracy by increasing the number of DCT coefficients observed in the low-to mid-frequency components. Our experiment results indicate that [-40, 40] is an appropriate range for observing a histogram, and the selection of DCT coefficients strongly depends on the image size because of the difference in the amount of useful statistical information available.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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掲載種別：研究論文（国際会議プロシーディングス）  

Nowadays, C programming is educated in many universities as the first computer language. It is also essential for studying algorithms and computer architecture. However, a lot of students find difficulty in the study, since it is not familiar to read and understand a C source code. Previously, Java programming learning assistant system (JPLAS) has been developed to assist Java programming study. It offers the value trace problem (VTP) for code reading study. A VTP instance consists of a source code and a set of questions, where each question asks the value of an important variable or the output message in the code. The correctness of an answer is marked through string matching with the correct one. In this paper, we study the value trace problem (VTP) for C programming. 40 VTP instances are generated using source codes for basic grammar concepts, fundamental data structures and algorithms in textbooks or websites. The application results to 25 students using the offline answering function confirm the effectiveness in detecting understanding levels of students and hard problems for them.

DOI： 10.1109/CANDARW51189.2020.00093

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担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）  

DOI： 10.4018/IJMCMC.2020100101

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：責任著者   掲載種別：研究論文（学術雑誌）  

Due to pandemic spreads of COVID-19 and increasing populations of seniors, exercises or performance practices at home have become important to maintain healthy lives around the world. World Health Organization (WHO) has announced the physical health determines the Quality of Life (QoL) of a human. Unfortunately, a lot of people have no exercise and may be in unhealthy conditions. In this paper, we propose an Exercise and Performance Learning Assistant System (EPLAS) to assist people practicing exercises or learning performances by themselves at home. EPLAS adopts inexpensive devices and free software for low-cost implementation. It offers a video content of model actions by an instructor to be followed by the user, where the reaction is rated by comparing the feature points of the human bodies extracted by an open-source software OpenPose. For evaluations, we conduct experiments of applying EPLAS with five Yoga poses to 41 persons in Indonesia, Japan, and Taiwan, and confirm the effectiveness of the proposal.

DOI： 10.25046/aj0505145

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.4018/IJMCMC.2020040102

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：ASSOC COMPUTING MACHINERY  

With the growing popularity of smartphone devices, the demand for mobile application programmers has been increasing, particularly for the most popular mobile platform Android. Then, Android application programming has become one of the most important subjects that students should learn in professional schools and universities in IT departments. To assist self-studies of students, we have developed Android Programming Learning Assistance System (APLAS). To guide students to reach correct answers for given assignments, APLAS adopts the Test-Driven Development (TDD) method to validate student answers automatically using JUnit and Robolectric. The learning model for APLAS consists of four stages where each stage has several topics. In this paper, we implement Advanced Widgets as the second topic in the Interactive Application stage and evaluate it through applications to students in an IT department in Indonesia.

DOI： 10.1145/3395245.3396198

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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その他リンク： https://dblp.uni-trier.de/conf/apsipa/2020

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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その他リンク： https://dblp.uni-trier.de/conf/apsipa/2020

掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

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その他リンク： https://dblp.uni-trier.de/conf/apsipa/2020

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/CANDARW51189.2020.00015

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その他リンク： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#BriantoroFMRAKK20

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Springer  

DOI： 10.1007/978-3-030-61108-8_15

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その他リンク： https://dblp.uni-trier.de/db/conf/bwcca/bwcca2020.html#HudaFKSIK20

掲載種別：研究論文（学術雑誌）   出版者・発行元：Institute of Electrical and Electronics Engineers ({IEEE})  

DOI： 10.1109/tifs.2019.2956587

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1108/IJWIS-07-2019-0032

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/978-3-030-29029-0_23

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/CANDARW51189.2020.00066

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その他リンク： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#AkhterTNKF20

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

For decades, Calligraphy has been a popular artistic activity in Japan, China, and some countries. To assist its self-learning, we have proposed the Calligraphy Learning Assistant System (CLAS) using projection mapping, where a learner can practice it by following the letter writing video of a teacher projected on the paper. In this paper, we newly implement a letter portion practice function in CLAS, such that learners may practice their weak portions with the video showing the writing by a teacher. It is expected that to repeat practicing weak portions is useful in improving the whole letter writing. Through applications to 12 novice students from Indonesia, Myanmar, China, and Kenya, we confirm the effectiveness of this function, where each student has significantly improved the calligraphy skill.

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掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

DOI： 10.1109/CANDARW51189.2020.00093

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その他リンク： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#XiqinFKAD20

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

To advance Java programming educations, Java Programming Learning Assistant System (JPLAS) has been developed and used in universities in Japan and Myanmar. JPLAS offers several types of programming exercises to cover different learning levels, including the element fill-in-blank problem (EFP) and the code completion problem (CCP). In CCP, an incomplete source code made by removing some elements is given to a student, and its completion is requested by filling in the missing elements properly. The answer is marked by comparing each statement with the corresponding one in the original code. In contrast to EFP, CCP does not show the locations of missing elements. In the trial, CCP has been implemented on offline JPLAS. Data exchange between a teacher and students in a Java programming course is made using USB memories, which takes large loads. In this paper, we implement CCP on the Web server for online JPLAS by extending the implementation of EFP. As well, the evaluations have confirmed the effectiveness of this implementation.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1504/IJSSC.2019.100017

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1108/IJWIS-08-2019-0038

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.25046/aj040411

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.25046/aj040602

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掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE  

DOI： 10.1108/IJWIS-07-2019-0032

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1587/transinf.2018MUP0003

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.12720/jcm.14.11.1009-1016

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掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE  

DOI： 10.1017/ATSIP.2018.28

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.17706/jsw.14.5.200-208

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

J-GLOBAL

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

An optimal detector known as MAP detector has been proposed for the probabilistic fingerprinting codes such as Tardos and Nuida codes. However, it needs two kinds of important information. One is the collusion strategy which is used at the generation of a pirated codeword from colluders' codewords, and the other is the number of colluders. In this study, we propose an estimator which outputs these two parameters from a pirated codeword. At the estimation, we measure a bias in the pirated codeword by observing the number of symbols "0" and "1", and compare with possible bias patterns calculated from collusion strategies and number of colluders. As a result of computer simulation, it is confirmed that a collusion strategy and number of colluders can be estimated with high probability. In addition, it is revealed that the traceability of the detector using the proposed estimator is extremely close to the optimal detector.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1587/transfun.E101.A.119

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Smart Innovation, Systems and Technologies  

DOI： 10.1007/978-3-319-63856-0_47

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1504/IJSSC.2018.097286

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出版者・発行元：IEEE  

DOI： 10.1109/ITW.2018.8613319

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jisa.2018.06.002

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掲載種別：研究論文（学術雑誌）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER INTERNATIONAL PUBLISHING AG  

An aesthetic 2D-barcode, e.g. QR code, carries a given message in the payload and yet its visual appearance resembles another given logo image. The requirement of embedding a message in a "cover" image is similar to digital watermarking but with a crucial difference that, for the aesthetic 2D-barcode, the decoder is predetermined and fixed. Hence the designs and performances of the aesthetic 2D-barcode heavily rely on the predetermined decoder. In this paper, we focus on the underlying systematic encoding function in QR code. We first formulate a framework that optimizes the visual appearance of the codeword and yet meets the coding requirement. Since finding such an optimal codeword is computationally expensive, we next propose a heuristic to search for a feasible solution, and incorporate image processing operations to enhance the visual appearance. Although our method is designed for QR code, our approach can be applied to other 2D-barcodes that employ similar coding mechanisms of error correction code.

DOI： 10.1007/978-3-319-53465-7_28

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出版者・発行元：IEEE  

DOI： 10.1109/APSIPA.2017.8282268

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

In Indonesia, river water plays important roles in human life; for example, for transportation and economic activities of the inhabitants. However, industrial, agricultural and domestic water is discarded into rivers directly in many developing countries, since drainage systems have not been completely constructed. Water quality monitoring using radio-controlled submarine provide an opportunity to develop baseline monitoring system for river water ecosystem health indicator. We propose a design modification of radio-controlled submarine for river water quality monitoring. Our design consists of modification for navigation system by added external motor, IMU and GPS; modification of processing and control system by added micro controllers and mini pc, and modification of water sensors system.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER-VERLAG BERLIN  

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 computational time in case of lots of OR literals in the formula. One of the example formulas consists of lots of birthdate attributes to prove age. This greatly increases the public parameters correspondent to attributes, which causes a large delay in the accumulator computation due to multiplications of lots of parameters. In this paper, we propose an anonymous credential system with constant-size proofs for monotone formulas on attributes, in order to obtain more efficiency in the proof generation. The monotone formula is a logic formula that contains any combination of AND and OR relations. Our approach to prove the monotone formula is that the accumulator is extended to be adapted to the tree expressing the monotone formula. Since the use of monotone formulas increases the expression capability of the attribute proof, the number of public parameters multiplied in the accumulator is greatly decreased, which impacts the reduction of the proof generation time.

DOI： 10.1007/978-3-319-22425-1_16

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

For ubiquitous network services, wireless local-area network (WLAN) systems using plural access-points (APs) are often deployed in a network field. Then, a host may detect signals from multiple APs that are interfered. This redundancy can cause performance degradations and energy wastes if a small number of hosts participates the network. On the other hand, if many hosts participate there, the number of APs should be increased so that the sufficient communication quality is provided for each host. Thus, the WLAN system is expected to be adaptive and elastic to changes of host loads. In this paper, we present an idea of the elastic WLAN system and its implementation design using Linux-PCs. The key technology for this system is the use of the AP aggregation algorithm that has been proposed to minimize the number of active APs in the field by aggregating APs using the virtual AP technology. By using Linux tools and commands, this system collects necessary information for the algorithm input, and controls the APs based on the algorithm output. The implementation and evaluation of our proposal will be in future works.

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER INT PUBLISHING AG  

In anonymous reputation systems, where after an interaction between anonymous users, one of the user evaluates the peer by giving a rating. Ratings for a user are accumulated, which becomes the reputation of the user. By using the reputation, we can know the reliability of an anonymous user. Previously, anonymous reputation systems have been proposed, using an anonymous e-cash scheme. However, in the e-cash-based systems, the bank grasps the accumulated reputations for all users, and the fluctuation of reputations. These are private information for users. Furthermore, the timing attack using the deposit times is possible, which makes the anonymity weak. In this paper, we propose an anonymous reputation system, where the reputations of users are secret for even the reputation manager such as the bank. Our approach is to adopt an anonymous credential certifying the accumulated reputation of a user. Initially a user registers with the reputation manager, and is issued an initial certificate. After each interaction with a rater, the user as the ratee obtains an updated certificate certifying the previous reputation summed up by the current rating. The update protocol is based on the zero-knowledge proofs, and thus the reputations are secret for the reputation manager. On the other hand, due to the certificate, the user cannot maliciously alter his reputation.

DOI： 10.1007/978-3-319-12160-4_22

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：SPRINGER INT PUBLISHING AG  

Group signatures allow a group member to anonymously sign a message on behalf of the group. One of the important issues is the revocation, and lots of revocable schemes have been proposed so far. The scheme recently proposed by Libert et al. achieves that O(1) or O(log N) efficiency except for the revocation list size (also the revocation cost), for the total number of members N and the number of revoked members R. However, since a signature is required for each subset in the used subset difference method, the size is about 900R Bytes in the 128-bit security. In the case of R = 100,000, it amounts to about 80 MB. In this paper, we extend the scheme to reduce the revocation list (also the revocation cost). In the proposed scheme, an extended accumulator accumulates T subsets, which is signed for the revocation list. The revocation list size is reduced by 1/T, although the public key size, membership certificate size and the cost of a witness computation needed for signing increase related to T.

DOI： 10.1007/978-3-319-12160-4_26

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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. © 2013 Springer-Verlag.

DOI： 10.1007/978-3-642-37682-5_35

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掲載種別：論文集(書籍)内論文   出版者・発行元：Springer Netherlands  

DOI： 10.1007/978-94-007-5651-9_3

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

With the advancement of communication technologies, multiple wireless local area networks (WLANs) have been often deployed in the same building for the Internet access services. Usually, their wireless access-points (APs) have been independently managed and operated by different groups such as departments or laboratories in a university or a company. Then, a WLAN user host can detect signals from multiple APs, which may increase the interference and the operation cost, and degrade the communication performance. As a result, the number of active APs should be minimized by aggregating the physical APs allocated in the field into limited ones by introducing virtual APs. In this paper, we define this AP aggregation problem for WLANs that aggregates the APs into the minimum number of active APs, and prove the NP-completeness of its decision problem. Then, we propose the heuristic algorithm that is composed of five phases. The effectiveness of our proposal has been verified through simulations in two instances. © 2012 Crown Copyright.

DOI： 10.1109/CISIS.2012.121

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記述言語：英語   出版者・発行元：Springer New York  

DOI： 10.1007/978-1-4614-1695-1_10

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出版者・発行元：IEEE  

DOI： 10.1109/BWCCA.2012.91

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記述言語：英語   出版者・発行元：Information and Media Technologies 編集運営会議  

Recently, ubiquitous Internet-access services have been provided by Internet service providers (ISPs) by deploying wireless local area networks (LANs) in public spaces including stations, hotels, and coffee shops. The IEEE802.1X protocol is usually used for user authentications to allow only authorized users to access services. Then, although user personal information of access locations, services, and operations can be easily collected by ISPs and thus, their strict management has been demanded, it becomes very difficult when multiple ISPs provide roaming services by their corporations. In this paper, we present an anonymous IEEE802.1X authentication system using a group signature scheme to allow user authentication without revealing their identities. Without user identities, ISPs cannot collect personal information. As an efficient revocable group signature scheme, we adopt the verifier-local revocation (VLR) type with some modifications for use of the fast pairing computation. We show the implementation of our proposal and evaluation results where the practicality of our system is confirmed for up to 1, 000 revoked users.

DOI： 10.11185/imt.5.751

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Information Processing Society of Japan  

Recently, ubiquitous Internet-access services have been provided by Internet service providers (ISPs) by deploying wireless local area networks (LANs) in public spaces including stations, hotels, and coffee shops. The IEEE802.1X protocol is usually used for user authentications to allow only authorized users to access services. Then, although user personal information of access locations, services, and operations can be easily collected by ISPs and thus, their strict management has been demanded, it becomes very difficult when multiple ISPs provide roaming services by their corporations. In this paper, we present an anonymous IEEE802.1X authentication system using a group signature scheme to allow user authentication without revealing their identities. Without user identities, ISPs cannot collect personal information. As an efficient revocable group signature scheme, we adopt the verifier-local revocation (VLR) type with some modifications for use of the fast pairing computation. We show the implementation of our proposal and evaluation results where the practicality of our system is confirmed for up to 1,000 revoked users.

DOI： 10.2197/ipsjjip.18.63

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/ISCE.2009.5156917

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/ISCE.2009.5156885

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Information Processing Society of Japan  

Group signature schemes with membership revocation have been intensively researched. In this paper, we propose revocable group signature schemes with less computational costs for signing/verification than an existing scheme without the update of the signer's secret keys. The key idea is the use of a small prime number embedded in the signer's secret key. By using simple prime integer relations between the secret prime and the public product of primes for valid or invalid members, the revocation is efficiently ensured. To show the practicality, we implemented the schemes and measured the signing/verification times in a common PC (Core2 DUO 2.13 GHz). The times are all less than 0.5 seconds even for relatively large groups (10,000 members), and thus our schemes are sufficiently practical.

DOI： 10.2197/ipsjjip.16.110

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記述言語：英語   出版者・発行元：Information and Media Technologies 編集運営会議  

Group signature schemes with membership revocation have been intensively researched. In this paper, we propose revocable group signature schemes with less computational costs for signing/verification than an existing scheme without the update of the signer's secret keys. The key idea is the use of a small prime number embedded in the signer's secret key. By using simple prime integer relations between the secret prime and the public product of primes for valid or invalid members, the revocation is efficiently ensured. To show the practicality, we implemented the schemes and measured the signing/verification times in a common PC (Core2 DUO 2.13GHz). The times are all less than 0.5 seconds even for relatively large groups (10, 000 members), and thus our schemes are sufficiently practical.

DOI： 10.11185/imt.3.768

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

In group signature schemes, a signature is anonymous for a verifier, while only a designated Privacy Manager (PM) can identify the signer. This identification is used for tracing a dishonest anonymous signer in case of an illegal act using the signature. However, PM can violate signers' anonymity. Recently, Brickell and Li propose a novel countermeasure for the anonymous dishonest signer without PM in the setting of the direct anonymous attestation. Here, we call the generalized group signature version anonymously revocable group signature scheme. In this scheme, after an illegal act using a group signature was found, the membership of the dishonest signer can be anonymously revoked for excluding the signer without the help of any PM. However, since the Brickell-Li scheme is based on the RSA assumption and the DDH assumption, the signature is long. In this paper, we propose a short anonymously revocable group signature scheme from supersingular curves, where we adopt the decision linear (DLIN) assumption. Compared to the simple adoption of the Brickell-Li DDH-based revoking approach to supersingular curves, the length of our signature is reduced to about from 30% to 60%. Copyright 2008 ACM.

DOI： 10.1145/1368310.1368359

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Springer-Verlag  

DOI： 10.1007/978-3-540-79549-0_28

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Studies of facial parts have been conducted in recent years in various fields of medical science and psychology, including studies of the lip contour and location. In fact, in the treatment of cleft lip patients in oral surgery, it is desirable to extract the precise lip contour and to identify its location on the face in order to plan the plastic surgery procedure and to follow up the site after surgery. Aiming at applications to dental treatment, in this study we attempt to extend the lip contour extraction procedure based on the deformable template to the case of a template with left-right asymmetry. An algorithm is also proposed for adjusting the hue and value thresholds in order to improve extraction accuracy and reduce the burden on the user. The proposal is evaluated using sample images of normal subjects and cleft lip patients. It is shown that the shape and location of the lip can be extracted precisely and automatically by the proposed method. In connection with application to dental clinics, we present an example of a quantitative evaluation of the lip shape by using the parameters extracted by the proposed method. © 2007 Wiley Periodicals, Inc.

DOI： 10.1002/scj.10668

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

In wavelength division multiplexing (WDM) technology, high-speed large-capacity communication is realized by transmitting multiple optical signals with different wavelengths in parallel on an optical fiber. In WDM technology, the logical topology of the network can generally be modified by changing the wavelength assignment to the transmitters and receivers. Thus it is important to develop an algorithm that derives the wavelength assignment that maximizes the transmission efficiency of the network. This paper considers a bidirectional Manhattan street network which has a regular topology, and proposes a hierarchical two-stage heuristic algorithm. In the first stage, the initial solution is derived by hierarchical region division and node assignment to the regions. In the second stage, the solution is improved by simulated annealing (SA). The proposed algorithm is evaluated by simulations of random instances and instances for which optimal solutions are already known. The effectiveness of the proposed algorithm is demonstrated through comparisons to the existing one. © 2007 Wiley Periodicals, Inc.

DOI： 10.1002/scj.10534

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE  

For a flexible and inexpensive large-scale access network to the Internet, we have studied the wireless mesh network composed of access points (APs) as wireless routers. Each AP has multihop wireless connections with the others by the wireless distribution system (WDS). In this network, communications around Internet gateways are usually very crowded and become the bottleneck of performance, because most traffic go through there for access to the Internet. To avoid this problem, the proper channel configurations of APs concerning multiple network interface cards (NICs) and their channel assignments are essential, where for the given network and traffics, the throughput should be maximized while the cost for channel configurations be minimized. In this paper, we formulate this channel configuration problem for AP communications in the wireless mesh network, and present its two-stage heuristic algorithm. The effectiveness of our approach is verified through extensive simulations.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/ietfec/e89-a.5.1275

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER-VERLAG BERLIN  

Previously Verifier-Local Revocation (VLR) group signature schemes from bilinear maps were proposed. In VLR schemes, only verifiers are involved in the revocation of a member, while signers are not involved in the revocation. Thus, the schemes are suitable for mobile environments. Furthermore, the previously proposed schemes satisfy an important property, the backward unlinkability. It means that even after a member is revoked, signatures produced by the member before the revocation remain anonymous. This property is needed in case a member leaves voluntarily or in case of a stolen key. In this paper an improved scheme is proposed, where the group signatures are shorter. This is achieved using a different assumption, DLDH assumption, and improving zero-knowledge proofs in the group signatures. The length of the proposed group signatures is about 53% of that of the previous ones.

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/ietfec/e88-a.5.1234

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

An approach of membership revocation in group signatures is verifier-local revocation (VLR for short). In this approach, only verifiers are involved in the revocation mechanism, while signers have no involvement. Thus, since signers have no load, this approach is suitable for mobile environments. Although Boneh and Shacham recently proposed a VLR group signature scheme from bilinear maps, this scheme does not satisfy the backward unlikability. The backward unlikability means that even after a member is revoked, signatures produced by the member before the revocation remain anonymous. In this paper, we propose VLR group signature schemes with the backward unlinkability from bilinear maps. © International Association for Cryptologic Research 2005.

DOI： 10.1007/11593447_29

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1109/ICON.2004.1409241

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The specification for a communication protocol is generally represented by a finite-state machine, and the operation of the machine is represented by transitions among states. The device implementing such specification is called the implementation under test (IUT). It is important for the IUT that its operation should be verified for all state transitions on the finite-state machine given in the specification. This test is called the conformance testing. In such testing it is important to generate efficiently a route containing all state transitions from the initial state. This problem is called the test sequence generation problem. This paper considers the test sequence generation problem for a communication protocol and proposes an application of an algorithm for satisfiability problem (SAT) that can flexibly handle various constraints, such as the order constraint and the time constraint among multiple constraints. The proposed method is applied to the dynamic host configuration protocol (DHCP) and its effectiveness is demonstrated. © 2003 Wiley Periodicals, Inc.

DOI： 10.1002/scj.10482

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCRIPTA TECHNICA-JOHN WILEY & SONS  

The radio network is a large-scale communication network in which a large number of stations are distributed over a wide area. Each station can communicate directly by radio packets only with neighborhood stations. Packet communication between stations which cannot communicate directly is realized by passing packets through multiple stations between them. For this purpose, when a packet communication request arises, the route for the packet and the transfer timing must be chosen so that the total transfer time is minimized and the efficiency of the radio network is maximized. It should be noted that the reliability, representing the probability that the required performance is achieved, fluctuates among the stations in the network due to the differences in the time of installation, the designed performance, and communication congestion. Consequently, this paper proposes a two-stage algorithm in which the route is assigned so that its reliability is larger than the required value. The proposed algorithm is composed of the iterative reliability satisfaction extraction procedure, in which a set of path candidates satisfying the reliability condition for the given transfer request, and the greedy neural network procedure, in which the route minimizing the cost is selected from the set of path candidates. The effectiveness of the proposed algorithm is demonstrated by simulation for networks with up to 500 stations. (C) 2002 Scripta Technica.

DOI： 10.1002/ecjc.1102

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1109/ICSMC.2001.972986

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scripta Technica Inc  

In this paper, we propose a neural network algorithm that uses the expanded maximum neuron model to solve the channel assignment problem of cellular radio networks, which is an NP-complete combinatorial optimization problem. The channel assignment problem demands minimizing the total interference between the assigned channels needed to satisfy all of the communication needs. The proposed expanded maximum neuron model selects multiple neurons in descending order from the neuron inputs in each neuron group. As a result, the constraints will always be satisfied for the channel assignment problem. To improve the accuracy of the solution, neuron fixing, which is a heuristic technique used in the binary neuron model, a hill-climbing term, a shaking term, and an Omega function are introduced. The effectiveness of these additions to the expanded maximum neuron model algorithm is demonstrated. Simulations of benchmark problems demonstrate the superior performance of the proposed algorithm over conventional algorithms in finding the solution.

DOI： 10.1002/(SICI)1520-6440(200011)83:11<11::AID-ECJC2>3.0.CO;2-D

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SCRIPTA TECHNICA-JOHN WILEY & SONS  

In a multicast packet switching system, multiple output ports can send out packets simultaneously by means of the packet copying function. In realizing such a switching system, the transmission pattern must be determined for successively arising transfer requests, so that the number of transmitted packets is maximized, while satisfying the constraints. This paper considers the one-shot scheduling problem formulated by Chen and colleagues, where all copies of the same packet are sent at the same time, and proposes a new solution method using a neural network. In the proposed solution method using the neural network, the binary neuron, which is suited to the digital techniques and hardware implementation, is employed together with the synchronous update scheme. In order to improve the convergence performance and the accuracy of the solution, an operational equation with an additional heuristic term and a coefficient setting procedure taking account of transfer requests are proposed. By simulations for cases of up to 1000 ports, it is shown that the proposed solution method using the neural network is better in deriving the solution than the conventional method. It is also shown that the considered problem is NP-hard. (C) 1999 Scripta Technica.

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記述言語：日本語   出版者・発行元：一般社団法人情報処理学会  

本論文では マキシマムニューロンを用いたN-Queen問題の解法を提案する. マキシマムニューロンは ニューラルネットワークによる組合せ最適化問題の効率的解法を目的として Takefujiらによって提案されたニューロンモデルである. マキシマムニューロンでは 解空間を構成するニューロンをグループに分割し 各グループ内でただ1つのニューロンのみが発火する. これにより 探索空間の大幅な縮小 ニューロン状態更新に必要な計算量の減少を実現している. 本論文では シミュレーションにより マキシマムニューロンによる解法が 従来のニューラルネットワーク解法より優れた求解性能を有することを示す. 特に 本解法が準同期式並列計算に非常に適した方法であることを明らかにする.This paper presents maximum neural network algorithms for N-queen problems using the maximum neuron model. The maximum neuron model is proposed by Takefuji et al. in order to provide efficient neural network solutions for combinatorial optimization problems. In this model, one and only one neuron id always fired in each group of neurons, which can not only reduce the searching space drastically but also save the computation load. The simulation results show that the performance of our maximum neural network surpasses the existing neural network for the same problem. Particularly, the maximum neural network in shown to be much suitable for the semi-synchronous computation.

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その他リンク： http://id.nii.ac.jp/1001/00013567/

記述言語：英語   出版者・発行元：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

This paper presents a binary neural network approach for link activation problems in multihop radio networks. The goal of the NP-complete problems is to find a conflict-free link activation schedule with the minimum number of time slots for specified communication requirements. The neural network is composed of NxM binary neurons for scheduling N links in M time slots. The energy functions and the motion equations are newly defined with heuristic methods. The simulation results through 14 instances with up to 419 links show that the neural network not only surpasses the best existing neural network in terms of the convergence rate and the computation time, but also can solve large scale instances within a constant number of iteration steps.

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記述言語：英語  

&lt;p&gt;A novel computational model for large-scale maximum clique problems is proposed and tested. The maximum clique problem is first formulated as an unconstrained quadratic zero-one programming and it is solved by minimizing the weight summation over the same partition in a newly constructed graph. The proposed maximum neural network has the following advantages: (1) coefficient-parameter tuning in the motion equation is not required in the maximum neural network while the conventional neural networks suffer from it; (2) the equilibrium state of the maximum neural network is clearly defined in order to terminate the algorithm, while the existing neural networks do not have the clear definition; and (3) the maximum neural network always allows the state of the system to converge to the feasible solution, while the existing neural networks cannot guarantee it. The proposed parallel algorithm for large-size problems outperforms the best known algorithms in terms of computation time with much the same solution quality where the conventional branch-and-bound method cannot be used due to the exponentially increasing computation time.&lt;/p&gt;

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記述言語：英語  

&lt;p&gt;The max cut problem, one of the NP-complete problems, was chosen to test the capability of an artificial neural network. The algorithm based on the maximum neural network was tested by 1000 randomly generated examples, including up to 300 vertex problems. The simulation result shows that the proposed parallel algorithm using the maximum neural network generates better solutions than Hsu&#039;s algorithm within one hundred iteration steps, regardless of the problem size.&lt;/p&gt;

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記述言語：英語  

&lt;p&gt;The circuit of the maximum neural network based on the switched capacitor technique is proposed. The performance of the proposed circuit was derived from SPICE simulation. The bipartite subgraph problem is solved by using the proposed circuit. The SPICE simulation result confirms the function of the network. Because the complexity of the proposed analog circuit is so small, it is possible to fabricate an optimization system in a single chip.&lt;/p&gt;

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担当区分：責任著者   掲載種別：研究発表ペーパー・要旨（全国大会，その他学術会議）  

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本グループでは，Javaプログラミング教育の高度化を狙いとして，Webを用いたJavaプログラミング学習支援システムJPLASを開発している．JPLASでは，学習者の作成した解答コードに対し，テストコードを用いたソフトウェアテストによる自動採点を行っている．その際，学習者は，テストコード中の情報（クラス，メソッド，変数の名称，アクセス修飾子，データ型など）を読み取り，解答コードに反映する必要がある．そのため，テストコードと誤りのある問題コードを与え，後者の修正を求める，コード修正問題を提案している．また，問題コード生成のために，ソースコードに誤りを施すアルゴリズムを提案している．本研究では，コード修正問題において，1)問題コードの多様化のための誤り情報の追加，2)テストコードを用いた問題コードの検証による正当性検証，3)問題コードの難易度の制御機能，の3つの改良を提案する．それらをJPLASに実装し，本学科Javaプログラミング授業での利用により，本提案の有効性を検証する．
To enhance Java programming educations, we have developed the Web-based Java Programming Learning Assistant System (JPLAS). JPLAS automatically marks the answer code of a student through software test using the test code. Thus, a student has to extract the necessary information from the test code to implement the answer code. To help a novice student, we proposed the code correction problem in the previous study, where a source code with errors, called a problem code, is given to a student with a test code, and is requested to be corrected to pass the test. We also proposed the algorithm to generate the problem code by making errors in the source code. In this study, we propose three improvements in the code correction problem: 1) to allow additional code items for errors for variation of the problem code, 2) to verify the correctness of the problem code by testing it, and 3) to implement the problem difficulty control function. We verify the effectiveness through applications in the Java programing course in our department.

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記述言語：日本語  

Javaは，可搬性，堅牢性，安全性に優れたプログラミング言語として，業務系システム，組み込みシステムなどに幅広く利用されており，そのプログラミング教育が重要である．そこで本研究室では，Webを用いたJavaプログラミング学習支援システムJPLAS（Java Programming Learning Assistant System）を開発し，授業での運用を行っている．現状のJPLASでは，教員がそれぞれの学生の問題解答状況を一覧で把握するための機能を有していない．また，全学生に同一の問題が出されており，個々の学生の学習レベルに適した問題が出題されていない．本発表では，以上の課題を解決するために，JPLASにおいて，エレメント補充問題を対象として，学生の解答状況の可視化機能，および，各学生に次に解くべき問題の推薦機能を実装する．特に後者では，これまでの学生の解答結果の分析により，各問題の難易度の算出法を提案し，各学生の解答履歴から，その学生に適した難易度の問題を次に解くべき問題として推薦する．評価として，教員に対して，解答状況可視化機能を用いたプログラミング演習を行ってもらう．また，学生に対して，問題推薦機能を用いた問題演習を行ってもらう．その後，アンケートの実施および解答結果の分析を行い，有効性を検証する．今後の課題として，問題難易度設定方法の再検討，エレメント補充問題以外の問題も対応可能な問題推薦機能への拡張があげられる．
As a portable, solid, secure programming language, Java is used widely such as business system and embedded system, thus its programming education is important. Therefore, we have developed the Web-based Java Programming Learning Assistant System (JPLAS) and used it in the Java programming course. JPLAS has no function which teacher can follow answering status of problems for each student. Additionally, it set the same problems to all of students, thus, it doesn't set the suitable problems corresponding to learning level for each student. In this presentation, we implement the answering status visualization function for each student and the recommendation function which recommend problems each student should solve the next for element fill in blank problems in JPLAS. In particular in the latter one, according to analysis of students' answering results so far, we propose the calculation method of problem difficulty and the system recommend the suitable problem to solve the next with learning level and answering history of each student. As an evaluation, we apply the answering status visualization function to the teacher in the programming exercise. Furthermore, we inspect the effectiveness by conducting a questionnaire survey and analyzing the answering results after students solve some of problems using problem recommendation function. In the future works, revision of the way to set up the problem level of difficulty and extension of problem recommendation function to follow other type of problems are some important tips.

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記述言語：日本語   出版者・発行元：映像情報メディア学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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その他リンク： https://astesj.com/v03/i01/p05/

担当区分：筆頭著者   記述言語：英語  

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.1109/GCCE.2017.8229400

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記述言語：英語  

DOI： 10.1109/ICCSN.2017.8230137

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.2197/ipsjjip.25.949

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：電子情報通信学会  

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記述言語：英語   出版者・発行元：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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担当区分：筆頭著者   記述言語：英語  

DOI： 10.1109/ICCE-China.2017.7991085

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記述言語：日本語   出版者・発行元：電子情報通信学会  

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.1587/transfun.E100.A.944

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記述言語：英語   出版者・発行元：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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記述言語：英語  

DOI： 10.1007/s11276-017-1462-9

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DOI： 10.1109/CANDAR.2017.20

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記述言語：英語   出版者・発行元：IJNC編集委員会  

Recently, an IEEE 802.11n access point (AP) prevailed over the wireless local area network (WLAN) due to the high-speed data transmission using the multiple input multiple output (MIMO) technology. Unfortunately, the signal propagation from the 802.11n AP is not uniform in the circumferential and height directions because of the multiple antennas for MIMO. As a result, the data transmission speed between the AP and a host could be significantly affected by their relative setup conditions. In this paper, we propose a minimax approach for optimizing the 802.11n AP setup condition in terms of the angles and the height in an indoor environment using throughput measurements. First, we detect a bottleneck host that receives the weakest signal from the AP in the field using the throughput estimation model. To explore optimal values of parameters for this model, we adopt the versatile parameter optimization tool. Then, we optimize the AP setup by changing the angles and the height while measuring throughput. For evaluations, we verify the accuracy of the model using measurement results and confirm the throughput improvements for hosts in the field by our approach.

DOI： 10.15803/ijnc.7.2_187

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記述言語：英語   出版者・発行元：IJNC編集委員会  

Recently, Wireless Local-Area Network (WLAN) has become prevailing as it provides flexible Internet access to users with low cost through installation of several types of access points (APs) in the network. Previously, we proposed the active AP configuration algorithm for the elastic WLAN system using heterogeneous APs, which dynamically optimizes the configuration by activating or deactivating APs based on traffic demands. However, this algorithm assumes that any active AP may use a different channel from the other ones to avoid interferences, although the number of non-interfered channels in IEEE 802.11 protocols is limited. In this paper, we propose the extension of the AP configuration algorithm to consider the channel assignment to the active APs under this limitation. Besides, AP associations of the hosts are modified to improve the network performance by averaging loads among channels. The effectiveness of our proposal is evaluated using the WIMNET simulator in two topologies. Finally, the elastic WLAN system including this proposal is implemented using Raspberry Pi for the AP. The feasibility and performance of the implementation are verified through experiments using the testbed.

DOI： 10.15803/ijnc.7.2_248

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記述言語：英語   出版者・発行元：IJNC編集委員会  

Recently, an IEEE 802.11n access point (AP) prevailed over the wireless local area network (WLAN) due to the high-speed data transmission using the multiple input multiple output (MIMO) technology. Unfortunately, the signal propagation from the 802.11n AP is not uniform in the circumferential and height directions because of the multiple antennas for MIMO. As a result, the data transmission speed between the AP and a host could be significantly affected by their relative setup conditions. In this paper, we propose a minimax approach for optimizing the 802.11n AP setup condition in terms of the angles and the height in an indoor environment using throughput measurements. First, we detect a bottleneck host that receives the weakest signal from the AP in the field using the throughput estimation model. To explore optimal values of parameters for this model, we adopt the versatile parameter optimization tool. Then, we optimize the AP setup by changing the angles and the height while measuring throughput. For evaluations, we verify the accuracy of the model using measurement results and confirm the throughput improvements for hosts in the field by our approach.

DOI： 10.15803/ijnc.7.2_187

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記述言語：英語   出版者・発行元：Emerald Group Publishing Ltd.  

Purpose-To advance Java programming educations, the authors have developed a Java Programming Learning Assistant System (JPLAS) as a web application system. JPLAS provides fill-in-blank problems for novices to study the grammar and basic programming skills through code reading. Design/methodology/approach-To select the blank elements with grammatically correct and unique answers from a given Java code, the authors have proposed the graph-based blank element selection algorithm. Then, the code for this problem should be highly readable to encourage novice students to study it. Because code readability can be improved by proper names for identifiers, the authors have also proposed the naming rule testing algorithm to identify codes with correct names. Findings-In this paper, the authors present a fill-in-blank problem workbook by collecting suitable Java codes from textbooks and Web sites and applying these algorithms with several extensions. The workbook consists of 16 categories with a considerable number of problems that follow the conventional learning order of Java programming. Originality/value-The proper set of ready-made fill-in-blank problems is effective in enhancing the usability of JPLAS both for teachers and students. For the preliminary evaluation, the authors assign a few problems to students. In coming semesters, the authors will use this workbook in the course to verify the adequacy of the proposal for novices.

DOI： 10.1108/IJWIS-12-2016-0076

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記述言語：英語  

DOI： 10.1109/AINA.2017.56

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その他リンク： https://www.graphyonline.com/journal/journal_article_inpress.php?journalid=IJCSE

担当区分：筆頭著者   記述言語：英語  

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記述言語：英語   出版者・発行元：IJNC編集委員会  

Recently, Wireless Local-Area Network (WLAN) has become prevailing as it provides flexible Internet access to users with low cost through installation of several types of access points (APs) in the network. Previously, we proposed the active AP configuration algorithm for the elastic WLAN system using heterogeneous APs, which dynamically optimizes the configuration by activating or deactivating APs based on traffic demands. However, this algorithm assumes that any active AP may use a different channel from the other ones to avoid interferences, although the number of non-interfered channels in IEEE 802.11 protocols is limited. In this paper, we propose the extension of the AP configuration algorithm to consider the channel assignment to the active APs under this limitation. Besides, AP associations of the hosts are modified to improve the network performance by averaging loads among channels. The effectiveness of our proposal is evaluated using the WIMNET simulator in two topologies. Finally, the elastic WLAN system including this proposal is implemented using Raspberry Pi for the AP. The feasibility and performance of the implementation are verified through experiments using the testbed.

DOI： 10.15803/ijnc.7.2_248

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DOI： 10.1108/IJWIS-12-2016-0076

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担当区分：筆頭著者   記述言語：英語  

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DOI： 10.1109/AINA.2017.56

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.1109/AINA.2017.60

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