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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

The Flutter framework with Dart programming allows developers to effortlessly build applications for both web and mobile from a single codebase. It enables efficient conversions to native codes for mobile apps and optimized JavaScript for web browsers. Since utilizing a wide range of widgets in Flutter ensures consistent experiences on various devices for users, it becomes crucial in programming education by providing a unified environment for learning app development while reducing the need for platform-specific knowledge. However, the setup of the Flutter environment is challenging for novice students due to its multiple steps, such as installing dependencies and configuring environments. To support independent learning for these students, it is essential to simplify the setup by providing user-friendly instructions and automated tools. In this paper, we present a Docker-based environment for Flutter app developments across Windows, Linux, and Mac through Visual Studio Code, ensuring a unified learning experience. This paper aims to simplify complex configurations and address the obstacles encountered by students when initiating Flutter projects. For the evaluation, we prepared three simple Flutter projects along with the setup environment in a Docker container. Then, we asked 24 Master’s students at Okayama University, Japan, to install the environment and modify the source codes in the projects independently by following the given instructions. The results show that all the students successfully completed the assignments, which confirms the efficiency and validity of our proposal.

DOI： 10.3390/info15040191

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

With the wide applications of the Internet of Things (IoT) in smart home systems, IEEE 802.11n Wireless Local Area Networks (WLANs) have become a frequently chosen communication technology due to their adaptability and affordability. In a high-density network of devices such as the smart home scenerio, a host often meets interferences from other devices and unequal Received Signal Strength (RSS) from Access Points (APs). This results in throughput unfairness/insufficiency problems between hosts communicating concurrently in WLAN. Previously, we have studied the throughput request satisfaction method to address this problem. It calculates the target throughput from measured single and concurrent throughputs of hosts and controls the actual throughput at this target one by applying traffic shaping at the AP. However, the insufficiency problem of maximizing the throughput is not solved due to interferences from other hosts. In this paper, we present an extension of the throughput request satisfaction method to maximize the throughput of a high-priority host under concurrent communications. It recalculates the target throughput to increase the actual throughput as much as possible while the other hosts satisfy the least throughput. For evaluations, we conduct experiments using the test-bed system with Raspberry Pi as the AP devices in several topologies in indoor environments. The results confirm the effectiveness of our proposal.

DOI： 10.3390/s24072173

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/iciet60671.2024.10542804

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

In this paper, we have developed the SEMAR (Smart Environmental Monitoring and Analytics in Real-Time) IoT application server platform for fast deployments of IoT application systems. It provides various integration capabilities for the collection, display, and analysis of sensor data on a single platform. Recently, Artificial Intelligence (AI) has become very popular and widely used in various applications including IoT. To support this growth, the integration of AI into SEMAR is essential to enhance its capabilities after identifying the current trends of applicable AI technologies in IoT applications. In this paper, we first provide a comprehensive review of IoT applications using AI techniques in the literature. They cover predictive analytics, image classification, object detection, text spotting, auditory perception, Natural Language Processing (NLP), and collaborative AI. Next, we identify the characteristics of each technique by considering the key parameters, such as software requirements, input/output (I/O) data types, processing methods, and computations. Third, we design the integration of AI techniques into SEMAR based on the findings. Finally, we discuss use cases of SEMAR for IoT applications with AI techniques. The implementation of the proposed design in SEMAR and its use to IoT applications will be in future works.

DOI： 10.3390/info15030153

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Authorship：Corresponding author  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Outdoor Location-Based Augmented Reality (LAR) applications require precise positioning for seamless integrations of virtual content into immersive experiences. However, common solutions in outdoor LAR applications rely on traditional smartphone sensor fusion methods, such as the Global Positioning System (GPS) and compasses, which often lack the accuracy needed for precise AR content alignments. In this paper, we introduce an innovative approach to enhance LAR anchor precision in outdoor environments. We leveraged Visual Simultaneous Localization and Mapping (VSLAM) technology, in combination with innovative cloud-based methodologies, and harnessed the extensive visual reference database of Google Street View (GSV), to address the accuracy limitation problems. For the evaluation, 10 Point of Interest (POI) locations were used as anchor point coordinates in the experiments. We compared the accuracies between our approach and the common sensor fusion LAR solution comprehensively involving accuracy benchmarking and running load performance testing. The results demonstrate substantial enhancements in overall positioning accuracies compared to conventional GPS-based approaches for aligning AR anchor content in the real world.

DOI： 10.3390/s24041161

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

A web-based Java programming learning assistant system (JPLAS) has been developed for novice students to study Java programming by themselves while enhancing code reading and code writing skills. One type of the implemented exercise problem is code writing problem (CWP), which asks students to create a source code that can pass the given test code. The correctness of this answer code is validated by running them on JUnit. In previous works, a Python-based answer code validation program was implemented to assist teachers. It automatically verifies the source codes from all the students for one test code, and reports the number of passed test cases by each code in the CSV file. While this program plays a crucial role in checking the correctness of code behaviors, it cannot detect code plagiarism that can often happen in programming courses. In this paper, we implement a code plagiarism checking function in the answer code validation program, and present its application results to a Java programming course at Okayama University, Japan. This function first removes the whitespace characters and the comments using the regular expressions. Next, it calculates the Levenshtein distance and similarity score for each pair of source codes from different students in the class. If the score is larger than a given threshold, they are regarded as plagiarism. Finally, it outputs the scores as a CSV file with the student IDs. For evaluations, we applied the proposed function to a total of 877 source codes for 45 CWP assignments submitted from 9 to 39 students and analyzed the results. It was found that (1) CWP assignments asking for shorter source codes generate higher scores than those for longer codes due to the use of test codes, (2) proper thresholds are different by assignments, and (3) some students often copied source codes from certain students.

DOI： 10.3390/analytics3010004

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Publishing type：Research paper (scientific journal)   Publisher：EJournal Publishing  

C programming has been a fundamental subject for a lot of university students studying programming lan guages, algorithms, and computer architecture. To enhance C programming education in schools, we have developed the C Programming Learning Assistant System (CPLAS) which provides a variety of programming assignments to cover different learning stages. The programming assignments offered by CPLAS allow the students to practice writing partial source code to learn grammar, code reading, and code debugging skills. However, the current assignments offered by CPLAS do not cover students to practice writing the whole C source code from scratch. Therefore, in this paper, we propose the Code Writing Problem (CWP) for students to write the C source code from scratch. In a CWP instance, a problem statement, an input list, and an expected output are given to the students. The students need to write the C source code from scratch by referring to the given information. The answer codes are marked through 1) compiling test, 2) execution test, and 3) output test. To avoid cheating by students, we use the random input generation method for each data type. To evaluate the proposal, we generated and assigned 11 CWP instances to the students. From their solution results, 10 out of 11 CWP instances achieved over 78% correct answer rate, and the feedback from the students confirmed the validity of the proposal.

DOI： 10.18178/ijlt.10.2.261-269

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Publishing type：Research paper (scientific journal)  

Nowadays, Java is one of the world’s most used object-oriented programming languages for its dependability and portability. To assist the self-studies of novice students, we have developed the Java programming learning assistance system (JPLAS). JPLAS offers several types of exercise problems for different difficulties, including the grammar-concept understanding problem (GUP), the mistake correction problem (MCP), the element fill-in-blank problem (EFP), and the phrase fill-in-blank problem (PFP), where a question asks to answer the corresponding keyword or phrase in the given source code. Unfortunately, some students cannot solve them well as the difficulty level is ascending. In this paper, to help such students, we propose a hint function that will show the first or more characters of each correct answer word in the answer interface on a web browser for JPLAS, when requested. The use of this function by a student can be traced by a teacher to analyze the performance and problem difficulty. For evaluations, we generated three instances for GUP, MCP, EFP, and PFP respectively, and assigned them to junior students taking the Java programming course in Okayama University, Japan. Their answer results found that the proposal is effective in helping students solve exercise problems in JPLAS, but the thinking time needs to be adjusted for PFP.

DOI： 10.18178/ijiet.2023.13.11.1995

Scopus

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Publishing type：Research paper (scientific journal)  

DOI： 10.17706/jsw.18.4.218-227

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/icvee59738.2023.10348237

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/gcce59613.2023.10315469

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/icce-berlin58801.2023.10375631

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Publishing type：Research paper (scientific journal)  

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

Scopus

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Publishing type：Research paper (scientific journal)  

DOI： 10.3390/s23146367

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Publishing type：Research paper (scientific journal)  

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

Scopus

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Publishing type：Research paper (scientific journal)  

DOI： 10.3390/signals4020015

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Publishing type：Research paper (scientific journal)  

DOI： 10.3390/a16010045

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Publishing type：Research paper (international conference proceedings)  

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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Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/ICCE-Taiwan58799.2023.10226698

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Other Link： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2023.html#LuFUK23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1145/3617733.3617736

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Other Link： https://dblp.uni-trier.de/db/conf/icccm/icccm2023.html#LuFUK23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315422

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#ZhangKHFH23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315351

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#KongZFHKH23

Publishing type：Research paper (scientific journal)  

DOI： 10.3390/info14070359

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Publishing type：Research paper (scientific journal)  

DOI： 10.3390/info14060300

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Publishing type：Research paper (international conference proceedings)  

DOI： 10.1145/3628454.3631856

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Other Link： https://dblp.uni-trier.de/db/conf/iait/iait2023.html#LuFWAMK23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315512

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#NaingFWA23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315607

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#AnggrainiXFHSF23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315417

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#PandumanFS23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/APSIPAASC58517.2023.10317147

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Other Link： https://dblp.uni-trier.de/db/conf/apsipa/apsipa2023.html#AkaiKF23

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/APSIPAASC58517.2023.10317492

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Other Link： https://dblp.uni-trier.de/db/conf/apsipa/apsipa2023.html#UraKF23

Publishing type：Research paper (scientific journal)  

DOI： 10.48550/arXiv.2302.14197

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Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/APSIPAASC58517.2023.10317291

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Other Link： https://dblp.uni-trier.de/db/conf/apsipa/apsipa2023.html#TanakaKF23

Publishing type：Research paper (international conference proceedings)  

In recent years, the utilization of location-based augmented reality (LAR) has gained popularity across various domains, including tourism, education, gaming, and advertising. The advancements in AR technology have made it easier to develop immersive LAR applications. ARCore, a widely adopted AR development library, enables the creation of location-based AR apps on Android devices. However, the implementation of ARCore in real-Time scenarios that demand significant computational resources, like outdoor pedestrian navigation, can vary depending on the chosen development environment. This research aims to explore and compare the running load performance of ARCore implementation in location-based AR applications developed with Unity and Android Native, which are two prevalent AR development platforms. The study involves building a prototype LAR application using both Unity and native Android, followed by comprehensive running load performance evaluations. The findings reveal that while both Unity and native Android apps can deliver compelling location-based AR experiences, native Android apps demonstrate superior performance and resource efficiency in outdoor scenarios, whereas Unity offers the advantage of multi-platform support and ease of development for complex 3D assets. These insights provide valuable guidance to developers in selecting the most suitable approach for developing location-based AR applications for navigation, aligning with their specific needs and requirements.

DOI： 10.1109/ICVEE59738.2023.10348201

Scopus

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：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

Web of Science

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Authorship：Corresponding author   Language：English  

Publishing type：Research paper (scientific journal)  

—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

Scopus

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Publishing type：Research paper (scientific journal)  

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

Scopus

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Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Currently, the User-PC computingsystem (UPC) has been studied as a low-cost and high-performance distributed computing platform. It uses idling resources of personal computers (PCs) in a group. The job-worker assignment for minimizing makespan is critical to determine the performance of the UPC system. Some applications need to execute a lot of uniform jobs that use the identical program but with slightly different data, where they take the similar CPU time on a PC. Then, the total CPU time of a worker is almost linear to the number of assigned jobs. In this paper, we propose a static assignment algorithm of uniform jobs to workers in the UPC system, using simultaneous linear equations to find the lower bound on makespan, where every worker requires the same CPU time to complete the assigned jobs. For the evaluations of the proposal, we consider the uniform jobs in three applications. In OpenPose, the CNN-based keypoint estimation program runs with various images of human bodies. In OpenFOAM, the physics simulation program runs with various parameter sets. In code testing, two open-source programs run with various source codes from students for the Android programming learning assistance system (APLAS). Using the proposal, we assigned the jobs to six workers in the testbed UPC system and measured the CPU time. The results show that makespan was reduced by 10% on average, which confirms the effectiveness of the proposal.

DOI： 10.3390/a15100369

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English  

Publishing type：Research paper (scientific journal)  

DOI： 10.3390/s22176436

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Publishing type：Research paper (international conference proceedings)   Publisher：ACM  

DOI： 10.1145/3556223.3556250

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Publishing type：Research paper (international conference proceedings)   Publisher：ACM  

DOI： 10.1145/3556223.3556227

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/iccci55554.2022.9850241

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English  

Authorship：Corresponding author   Language：English  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Language：English   Publishing type：Research paper (international conference proceedings)  

Publishing type：Research paper (scientific journal)  

DOI： 10.3390/info13050211

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754790

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#PuspitaningayuF22

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754807

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#HtetFKZSAK22

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754593

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#LuCFKU22

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech53646.2022.9754593

Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2022.html#LuCFKU22

Publishing type：Research paper (international conference proceedings)  

DOI： 10.1007/978-3-031-14463-9_16

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Other Link： https://dblp.uni-trier.de/db/conf/cdmake/cdmake2022.html#KuribayashiKF22

Publishing type：Research paper (scientific journal)  

DOI： 10.4018/ijmcmc.301275

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Publishing type：Research paper (scientific journal)  

DOI： 10.12720/jcm.17.8.592-599

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Publishing type：Research paper (scientific journal)  

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

Scopus

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Publishing type：Research paper (international conference proceedings)  

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

Scopus

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Language：English   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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.

Web of Science

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.iot.2022.100583

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Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/CANDARW53999.2021.00051

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2021w.html#KamoyedjiFHK21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1109/GCCE59613.2023.10315660

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2023.html#MonQWFK23

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/GCCE53005.2021.9621949

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Other Link： https://dblp.uni-trier.de/db/conf/gcce/gcce2021.html#LuQFAHLK21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

Recently, Android programming educations have become important in IT departments in universities due to the strong market demands. The Android Programming Learning Assistance System (APLAS) is a self-learning platform for Android programming. It provides assignments to students where the correctness of their answers can be checked automatically using unit testing tools through a web application. For each assignment in APLAS, students need to submit multiple files with the correct configuration as one project. However, many students cause errors in the current implementation of submitting one by one the files in the Android project made using Android Studio. In this paper, we implement two submission methods for reducing errors in APLAS. The zip-file method makes the zipped file of the Android project to be submitted. The GitHub-link method synchronizes the files in the Android project through the URL of the GitHub project. For evaluations, we asked 40 students to solve three assignments in APLAS and submit the answer files by freely choosing one method. The results show that the zip-file method was most popular and the GitHub-link method produced least errors.

DOI： 10.1109/3ICT53449.2021.9581553

Scopus

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：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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Other Link： https://www.emerald.com/insight/content/doi/10.1108/IJWIS-03-2021-0025/full/html

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/ICCE-TW52618.2021.9603085

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Other Link： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#FunabikiLSHKUK21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/ICCE-TW52618.2021.9603037

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Other Link： https://dblp.uni-trier.de/db/conf/icce-tw/icce-tw2021.html#PuspitaningayuF21

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Authorship：Corresponding author   Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：ACM  

DOI： 10.1145/3479162.3479176

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Other Link： https://dblp.uni-trier.de/db/conf/icccm/icccm2021.html#HtetFKZK21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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Other Link： https://dblp.uni-trier.de/db/journals/ieicetd/ieicetd104.html#MuneneFBRAKK21

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s42979-021-00580-1

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Other Link： http://link.springer.com/article/10.1007/s42979-021-00580-1/fulltext.html

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：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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Other Link： https://www.emerald.com/insight/content/doi/10.1108/IJWIS-11-2020-0070/full/html

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391784

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#LuFKAD21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391812

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#LuAKFAS21

Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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Other Link： https://dblp.uni-trier.de/db/journals/ijnc/ijnc11.html#BriantoroFRMKK21

Publishing type：Research paper (scientific journal)  

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Other Link： https://dblp.uni-trier.de/db/journals/corr/corr2107.html#abs-2107-02961

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/LifeTech52111.2021.9391894

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Other Link： https://dblp.uni-trier.de/db/conf/lifetech/lifetech2021.html#KyawFK21

Publishing type：Research paper (international conference proceedings)   Publisher：ACM  

DOI： 10.1145/3437880.3460402

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Other Link： https://dblp.uni-trier.de/db/conf/ih/ihmmsec2021.html#KuribayashiTSYF21

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

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Other Link： https://dblp.uni-trier.de/rec/conf/apsipa/2021

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Publishing type：Research paper (international conference proceedings)  

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

Scopus

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Authorship：Lead author   Publishing type：Research paper (scientific journal)  

DOI： 10.4018/IJMCMC.2020100101

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Institute of Electrical and Electronics Engineers Inc.  

Nowadays, IEEE802.11n wireless local-area networks (WLANs) have been widely deployed due to its high-speed data transmission. The channel bonding is one of the key technologies to realize it. However, the data transmission throughput can be dropped when nearby multiple links are concurrently communicating, caused by interference. Previously, we have studied the throughput-drop estimation model for the links using the channel bonding, which considers the channel distance and the received signal strength (RSS) of the interfered links. In this paper, we further explore the throughput-drop estimation model for concurrently communicating two links without the channel bonding by extending the previous model. The effectiveness of the proposal is confirmed through experiments where the estimated throughput well matches the measured throughput.

DOI： 10.1109/ICCE-Taiwan49838.2020.9258012

Scopus

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)  

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

Scopus

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4018/IJMCMC.2020040102

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ICST  

A programming education is one of the most important fields in Information and Education Technology. Funabiki et al. have developed a Web-based Java Programming Learning Assistant System (JPLAS). JPLAS mainly provides two types of problems, namely the code writing problem and the fill-in-blank problem, to support students' self-studies at various learning levels. Particularly in the fill-in-blank problem (FIBP), the system requires an efficient algorithm to find a maximal clique of the compatibility graph in advance in order to obtain a maximal set of blank elements with unique answers. In this paper, we investigate the performance of a metaheuristic algorithm based on an iterated local search for solving the maximum weight clique problem (MWCP), which is an important generalization of the maximum clique problem, given as an extension of the compatibility graph in the FIBP. Computational results show that our metaheuristic algorithm is capable of finding satisfactory weighted cliques efficiently for well-known benchmark graphs and the performance of our algorithm is comparable to those of state-of-the-art metaheuristics for the MWCP.

DOI： 10.1145/3395245.3396407

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Engineering and Technology Publishing  

Currently, various types of access-points (APs) and hosts can be used in IEEE802.11n/ac wireless local-area networks (WLANs). Previously, we have studied the holding AP assignment algorithm to find an optimal assignment of the holding APs into the network field. Here, the 11n link throughput is obtained by using simple equations, and the 11ac link throughput is obtained by multiplying it with a constant value larger than 1, assuming the former link is faster than the latter one. Unfortunately, our experiments found that the 11ac link throughput is more quickly decreased as the link distance increases than the 11n. Thus, our algorithm may produce incorrect solutions in some cases. In this paper, we adopt the throughput estimation model for the 11ac/n link as the accurate estimation method in the holding AP assignment algorithm, and confirm the effectiveness of improving the total throughput performance through simulations in three instances using the WIMNET simulator.

DOI： 10.12720/jcm.15.1.81-87

Scopus

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

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Other Link： https://dblp.uni-trier.de/conf/apsipa/2020

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

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Other Link： https://dblp.uni-trier.de/conf/apsipa/2020

Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

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Other Link： https://dblp.uni-trier.de/conf/apsipa/2020

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/CANDARW51189.2020.00015

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#BriantoroFMRAKK20

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Springer  

DOI： 10.1007/978-3-030-61108-8_15

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Other Link： https://dblp.uni-trier.de/db/conf/bwcca/bwcca2020.html#HudaFKSIK20

Publishing type：Research paper (scientific journal)   Publisher：Institute of Electrical and Electronics Engineers ({IEEE})  

DOI： 10.1109/tifs.2019.2956587

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1108/IJWIS-07-2019-0032

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Advances in Intelligent Systems and Computing  

DOI： 10.1007/978-3-030-29029-0_23

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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/CANDARW51189.2020.00066

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#AkhterTNKF20

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/CANDARW51189.2020.00093

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Other Link： https://dblp.uni-trier.de/db/conf/ic-nc/candar2020w.html#XiqinFKAD20

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Springer Verlag  

To advance Java programming educations, we have developed a Web-based Java Programming Learning Assistant System (JPLAS). JPLAS offers several types of programming exercises to cover various learning stages of Java programming, where any answer can be marked automatically on the server. The code writing problem requests a student to write a source code satisfying the specifications described in the test code, such as names and data types of classes, methods, and variables, so that the answer code is marked by running the test code on JUnit. However, it appears challenging for a novice student to extract the specifications from the test code properly. In this paper, we propose a code correction problem as a new type programming exercise for reading and debugging codes, which gives a source code with errors called a problem code with the corresponding test code, and requests students to correct the problem code to pass the test code. We also propose the error generation algorithm to generate the problem code from a sample source code automatically. We verify the effectiveness of our proposal through applications of seven assignments of the code correction problem to 45 students in the Java programing class in Okayama University.

DOI： 10.1007/978-3-030-22354-0_60

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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DOI： 10.1504/IJSSC.2019.100017

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1108/IJWIS-08-2019-0038

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.25046/aj040411

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.25046/aj040602

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Publishing type：Research paper (scientific journal)   Publisher：IEEE  

DOI： 10.1108/IJWIS-07-2019-0032

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Publishing type：Research paper (scientific journal)  

DOI： 10.1587/transinf.2018MUP0003

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.12720/jcm.14.11.1009-1016

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Publishing type：Research paper (scientific journal)   Publisher：IEEE  

DOI： 10.1017/ATSIP.2018.28

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.17706/jsw.14.5.200-208

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：Springer Verlag  

To enhance Java programming educations in schools, we have developed a Web-based Java Programming Learning Assistant System (JPLAS) that provides a variety of programming assignments to cover different learning stages. For the first stage, JPLAS offers the element fill-in-blank problem where students study the grammar and code reading through filling the blank elements, composed of reserved words, identifiers, and control symbols, in a high-quality code. Unfortunately, it has been observed that students can fill the blanks without reading the code carefully, because the choice is limited for each blank. In this paper, we propose a code completion problem as a generalization of the element fill-in-blank problem. To solve the drawback, it does not explicitly show blank locations in the code, which expects students to carefully read the code to understand the grammar and code structure. The correctness of the answer is verified through string matching of each statement with the filled elements and the corresponding correct one. Besides, to encourage students to study readable code writing, the correct statement satisfies the coding rules including the spaces. For evaluations, we generated six code completion and element fill-in-blank problems respectively, and asked ten students in two universities to solve them. Their solution results show that the code completion problem is much harder than the element fill-in-blank problem, and requires far deeper code reading and understanding of coding rules.

DOI： 10.1007/978-3-319-93659-8_78

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Language：English   Publishing type：Research paper (international conference proceedings)  

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Universitas Ahmad Dahlan  

The current air quality monitoring system cannot cover a large area, not real-time and has not implemented big data analysis technology with high accuracy. The purpose of an integration Mobile Sensor Network and Internet of Things system is to build air quality monitoring system that able to monitor in wide coverage. This system consists of Vehicle as a Mobile Sensors Network (VaaMSN) as edge computing and Smart Environment Monitoring and Analytic in Real-time (SEMAR) cloud computing. VaaMSN is a package of air quality sensor, GPS, 4G Wi-Fi modem and single board computing. SEMAR cloud computing has a time-series database for real-time visualization, Big Data environment and analytics use the Support Vector Machines (SVM) and Decision Tree (DT) algorithm. The output from the system are maps, table, and graph visualization. The evaluation obtained from the experimental results shows that the accuracy of both algorithms reaches more than 90%. However, Mean Square Error (MSE) value of SVM algorithm about 0.03076293, but DT algorithm has 10x smaller MSE value than SVM algorithm.

DOI： 10.12928/TELKOMNIKA.v16i6.10152

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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Language：English   Publishing type：Research paper (international conference proceedings)  

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DOI： 10.1587/transfun.E101.A.119

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Publishing type：Research paper (scientific journal)   Publisher：Smart Innovation, Systems and Technologies  

DOI： 10.1007/978-3-319-63856-0_47

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1504/IJSSC.2018.097286

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Publisher：IEEE  

DOI： 10.1109/ITW.2018.8613319

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DOI： 10.1016/j.jisa.2018.06.002

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Publisher：IEEE  

DOI： 10.1109/APSIPA.2017.8282268

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer Science and Business Media Deutschland GmbH  

To advance Java programming educations, we have developed a Java Programming Learning Assistant System (JPLAS) as a Web application system. JPLAS provides fill-in-blank problems for novice students to study the grammar and basic programming skills through code reading. To select the blank elements with grammatically correct and unique answers from a given code, we have proposed the graph-based blank element selection algorithm. Then, we generated and assigned fill-in-blank problems to students in Java programming course for two years. Unfortunately, the teacher selected original Java codes rather arbitrarily, which may degrade educational effects. Besides, this algorithm has been continuously extended to enhance the variations of generated problems. In this paper, we present a workbook design for fill-in-blank problems in JPLAS by collecting suitable Java codes from textbooks and Web sites, and applying the extended algorithm, so that they can be instantly and properly assigned to students. This workbook design consists of 15 categories with a considerable number of problems that follow the conventional learning order of Java programming. For the preliminary evaluation, we assign some problems to novice students. In the coming semester, we will use this workbook in the course to verify the adequacy of our proposal for novice students.

DOI： 10.1007/978-3-319-49106-6_31

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (international conference proceedings)  

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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Publishing type：Part of collection (book)   Publisher：Springer Netherlands  

DOI： 10.1007/978-94-007-5651-9_3

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Language：English   Publishing type：Research paper (international conference proceedings)  

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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Language：English  

Nowadays, cooking everyday is hard for busy persons such as workers, students, and child-rearing families, because the time is limited on weekdays. At the same time, it is important for a healthy diet not to rely on eating-out and instant foods heavily. One solution to this situation is to cook dishes for the whole week on the weekend and eat them on the following weekdays. Then, the way of cooking with a good cooking-step schedule for multiple dishes is very important to save the time. In this chapter, we first propose a cooking model to estimate the cooking time accurately under various conditions including the kitchen layout and the number of cooks. Then, using this model, we propose a cooking-step scheduling algorithm for simultaneous cooking of multiple dishes under the cooking time constraint. Through experiments, we verify the effectiveness of our model and algorithm, where the cooking time difference between the model and the real cooking is only 2 min. © 2012 Springer Science+Business Media, LLC.

DOI： 10.1007/978-1-4614-1695-1_10

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Publisher：IEEE  

DOI： 10.1109/BWCCA.2012.91

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Language：English   Publisher：Information and Media Technologies Editorial Board  

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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

Recently, Web-page browsing opportunities at multimodal browsing sizes have increased due to developments of various terminals. Meanwhile, most Web pages have been designed to fit to the standard size. As a result, the screen scroll operation is necessary to access the main content at a small size, whereas the blank space becomes large at a large size. In this paper, we propose a Web-page layout optimization method for multimodal browsing sizes by focusing on the standard Web design style with the separation of the document structure description by an XHTML file and the appearance description by a CSS file. Our method automatically generates a set of CSS files fit to different sizes from the files designed for the standard size by a user. Then, it dynamically switches to the CSS file fit to the current browsing size using JavaScript. We confirm the practicality of our proposal through experiments of the Web page generation and access at various sizes. ©2009 IEEE.

DOI： 10.1109/ISCE.2009.5156917

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Language：English   Publishing type：Research paper (international conference proceedings)  

Currently, several streaming servers are available to provide a variety of multimedia applications such as VoD (Videoon-Demand), IP-phone, and IP-TV. As a result, the provision of multiple streaming servers on a single machine using the virtualization technology has become important in order to save the operational/management costs while enhancing the performance and the reliability of the system. In this paper, we show the performance evaluation of two representative open source softwares for the virtualization technology, Xen and OpenVZ, in various configurations of applications on three open source streaming servers, Red5, Darwin, and VLC. Our experimental results indicate that OpenVZ provides the better performance for streaming applications with Darwin and VLC whereas Red5 can run only on Xen. ©2009 IEEE.

DOI： 10.1109/ISCE.2009.5156885

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publisher：Information and Media Technologies Editorial Board  

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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Language：English   Publishing type：Research paper (international conference proceedings)  

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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Language：English   Publishing type：Research paper (international conference proceedings)  

DOI： 10.1007/978-3-540-79549-0_28

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Language：English   Publishing type：Research paper (scientific journal)  

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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Language：English   Publishing type：Research paper (scientific journal)  

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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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG  

Group signature schemes with membership revocation have been intensively researched. However, signing and/or verification of some existing schemes have computational costs of O(R), where R is the number of revoked members. Existing schemes using a dynamic accumulator or a similar technique have efficient signing and verifications with O(1) complexity. However, before signing, the signer has to modify his secret key with O(N) or O(R) complexity, where N is the group size. Therefore, for larger groups, signers suffer from enormous costs. On the other hand. an efficient scheme for middle-scale groups with about 1,000 members is previously proposed, where the signer need not modify his secret key. However this scheme also suffers from heavy signing/verification costs for larger groups with more than 10,000 members. In this paper, we adapt the middle-scale scheme to larger groups ranging from 1,000 to 1.000.000 members. At the sacrifice of the group manager's slight cost, our signing/verification is sufficiently efficient.

DOI： 10.1093/ietfec/e89-a.5.1275

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Institute of Electronics, Information and Communication, Engineers, IEICE  

The wavelength-division multiplexing (WDM) technology has been popular in communication societies for providing very large communication bands by multiple lightpaths with different wavelengths on a single optical fiber. Particularly, a double-ring optical network architecture based on the packet-over-WDM technology such as the HORNET architecture, has been extensively studied as a next generation platform for metropolitan area networks (MANs). Each node in this architecture is equipped with a wavelength-fixed optical-drop and a fast tunable transmitter so that a lightpath can be established between any pair of nodes without wavelength conversions. In this paper, we formulate the optical-drop wavelength assignment problem (ODWAP) for efficient wavelength reuse under heterogeneous traffic in this network, and prove the JVP-completeness of its decision problem. Then, we propose a simple heuristic algorithm for the basic case of ODWAP. Through extensive simulations, we demonstrate the effectiveness of our approach in reducing waiting times for packet transmissions when a small number of wavelengths are available to retain the network cost for MANs. Copyright © 2005 The Institute of Electronics, Information and Communication Engineers.

DOI： 10.1093/ietfec/e88-a.5.1234

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Language：English   Publishing type：Research paper (international conference proceedings)  

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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Language：English   Publishing type：Research paper (international conference proceedings)  

This paper presents a hierarchical chordal ring network topology (HCRN) as a regular logical topology for multihop WDM networks. In order to minimize the traffic increase and the transmission delay through the network due to packet relays or hops on intermediate nodes in the multihop network, the network topology is hierarchically constructed in HCRN, so that more lightpaths are assigned to connections between nearby nodes than those for distant nodes, while the maximum hop between any pair of nodes is restrained. This hierarchical topology is also beneficial to reduce the number of required wavelengths through increasing their reuses by multiple lightpaths, which is important for cost-conscious metropolitan area networks. Through comparisons on the network diameter and the number of required wavelengths with the original chordal ring network topology, we show the effectiveness of our proposed HCRN. © 2004 IEEE.

DOI： 10.1109/ICON.2004.1409241

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Language：English   Publishing type：Research paper (scientific journal)  

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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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The satisfiability problem (SAT) is a typical NP-complete problem where a wide range of applications has been studied. Given a set of variables U and a set of clauses C, the goal of SAT is to find a truth assignment to variables in U such that every clause in C is satisfied if it exits, or to derive the infeasibility otherwise. This paper presents an approximation algorithm called a minimal-state processing search algorithm for SAT (MIPS_SAT). MIPS_SAT repeatedly transits minimal states in terms of the cost function for searching a solution through a construction stage and a refinement stage. The first stage greedily generates an initial state composed of as many satisfied clauses as possible. The second stage iteratively seeks a solution while keeping state minimality. The performance of MIPS_SAT is verified through solving DIMACS benchmark instances.

DOI： 10.1109/ICSMC.2001.972986

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：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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Language：English   Publishing type：Research paper (scientific journal)   Publisher：John Wiley and Sons Inc.  

The graph partitioning problem is an NP hard problem of deriving the partitioning of each vertex such that the total stun of the edge weights among the groups is minimized and the total sum of the vertex weights in each group is less than the upper limit. In this paper, a neural network solution is proposed in which the binary neurons are used for the graph 2-partitioning problem. In the present neural network, an energy function that is applicable to graphs both with and without edge and vertex weights is defined. For improvement of solution accuracy, shaking terms are introduced into the operating equation. To evaluate the solution search capability of the present method, simulations are carried out for random graphs, together with the KL method proposed by Kernighan and Lin, and the FM method proposed by Fiduccia and Mattheyses. From the simulation results, it is shown that the solutions obtained by the present method are the best. © 1999 Scripta Technica.

DOI： 10.1002/(sici)1520-6440(199912)82:12<34::aid-ecjc4>3.0.co;2-5

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Scripta Technica Inc  

This paper presents an N2 neuron N-parallel computation method for a neural network for the N queens problem. In this method, the N2 neurons are partitioned into N groups of N neurons, where the states of N neurons in N different groups are updated synchronously and the states in the same group are updated sequentially. First, we compare the performance of two existing neural networks for the N queens problem in order to show that Takefuji's neural network is best in the sequential method. Then, we show that even the improved neural network using the N2-parallel method cannot provide the same performance as that using the using sequential method. Lastly, we propose an N-parallel method to achieve high performance and parallel computation simultaneously.

DOI： 10.1002/(SICI)1520-6440(199711)80:11<12::AID-ECJC2>3.0.CO;2-U

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Language：English   Publishing type：Research paper (international conference proceedings)  

An «evolutionary neural network (ENN)» is presented for the max cut problem of an undirected graph G(V, E) in this paper. The goal of the NP-hard problem is to find a partition of V into two disjoint subsets such that the cut size be maximized. The cut size is the sum of weights on edges in E whose endpoints belong to different subsets. The ENN combines the evolutionary initialization scheme of the neural state into the energy minimization criteria of the binary neural network. The performance of ENN is evaluated through simulations in randomly weighted complete graphs and unweighted random graphs with up to 1000 vertices. The results show that the evolutionary initialization scheme drastically improves the solution quality. ENN can always find better solutions than the maximum neural network, the mean field annealing, the simulated annealing, and the greedy algorithm. © 1997 IEEE.

DOI： 10.1109/ICNN.1997.616215

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Language：Japanese   Publisher：Information Processing Society of Japan (IPSJ)  

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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Other Link： http://id.nii.ac.jp/1001/00013567/

Language：English   Publisher：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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&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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&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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&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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Authorship：Corresponding author   Publishing type：Research paper, summary (national, other academic conference)  

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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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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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Other Link： https://astesj.com/v03/i01/p05/

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

To advance Java programming studies, we have developed the Java Programming Learning Assistant System (JPLAS). The test code plays a critical role in verifying the correctness of the source code from a student automatically at the server in the code writing problem in JPLAS. Previously, we proposed the test code generation tool that automatically generates the test code from the given source code containing standard inputs/outputs that novice students are expected to study in advance. In this paper, we extend this tool to handle the source code with file inputs/outputs. By applying the extended tool to three codes containing file inputs/outputs, the correctness of the generated test codes is confirmed.

DOI： 10.1109/GCCE.2017.8229400

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