MDPI AG Acta Medica Okayama 1424-8220 26 5 2026 A Proposal of Secure and Automated Over-the-Air Firmware Update Mechanism for IoT Devices Using Continuous Integration and Continuous Delivery 1535 EN Noprianto Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University Komang Candra Brata Department of Information and Communication Systems, Okayama University I Nyoman Darma Kotama Department of Information and Communication Systems, Okayama University The Internet of Things (IoT) technology has grown rapidly over the past decade, resulting in deployments of thousands of IoT devices around the world. Then, managing firmware updates for these numerous devices poses significant challenges. Firmware updates face issues such as version rollback, modified firmware files, and potential man-in-the-middle (MITM) attacks, highlighting the need for a secure over-the-air (OTA) firmware update mechanism. In this paper, we propose an automated OTA firmware update mechanism, integrated with continuous integration (CI) and continuous delivery (CD) to ensure trusted sources for firmware origins. It offers security, error handling during firmware updates, and monitoring of the update process. For evaluations, we implemented the proposal with the SEMAR IoT application server that has been implemented in our previous studies. Then, we verified the integrity and authentication, measured the performance and resource utilization, and performed benchmarking tests to assess the efficiency. The results demonstrate that the proposal is sufficiently reliable and efficient. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 1424-8220 26 4 2026 A Generative AI–Based Technical Data Extraction Tool for IoT Application Systems 1081 EN Dezheng Kong Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University I Nyoman Darma Kotama Department of Information and Communication Systems, Okayama University Zihao Zhu Department of Information and Communication Systems, Okayama University Alfiandi Aulia Rahmadani Department of Information and Communication Systems, Okayama University Nowadays, Internet of Things (IoT) application systems play an essential role in smart cities, industry, healthcare, agriculture, and smart homes. For non-expert users, designing and implementing IoT application systems remains challenging, especially when configuring sensors, edge devices, and server platforms. To support configuration tasks of IoT application systems, we have developed an AI-based setup assistance tool. However, AI models still fail to reliably support newly released or previously unseen devices, sometimes producing incomplete or erroneous outputs that may lead to configuration failures. Incorporating their technical-document information into Retrieval-Augmented Generation (RAG) is an effective way to supplement AI knowledge and improve reliability. In this paper, we propose a generative AI-based technical data extraction tool to address the challenges. It extracts essential technical information using the schema-based extraction from given PDF or HTML datasheets and converts it into a structured format suitable for AI-supported configurations. A local vector database is used to enable semantic similarity retrieval and provide document-grounded evidence for RAG-based answering, ensuring consistent support for previously unseen IoT devices. For evaluations, we applied the proposal to several sensor and device datasheets and compared extracted specifications with ground-truth values to measure accuracy and completeness. Then, we compared end-to-end configuration QA reliability against a commercial baseline (ChatPDF) using the golden benchmark. The results show that the proposed tool reliably acquires key specifications and significantly improves end-to-end configuration QA reliability. Across 960 golden QA pairs, the proposed method improves Recall from 0.636 to 0.926 and Accuracy from 0.595 to 0.807 compared with ChatPDF. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 1999-4893 19 2 2026 A Slide Annotation System with Multimodal Analysis for Video Presentation Review 110 EN Amma Liesvarastranta Haz Department of Information and Communication Systems, Okayama University Komang Candra Brata Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University Evianita Dewi Fajrianti Human Centric Multimedia Research Laboratory, Department of Informatic and Computer Engineering, Politeknik Elektronika Negeri Surabaya Sritrusta Sukaridhoto Human Centric Multimedia Research Laboratory, Department of Informatic and Computer Engineering, Politeknik Elektronika Negeri Surabaya With the rapid growth of online presentations, there has been an increasing need for efficient review of recorded materials. In typical presentations, speakers verbally elaborate on each slide, providing details not captured in the slides themselves. Automatically extracting and embedding these verbal explanations at their corresponding slide locations can greatly enhance the review process for audiences. This paper presents a Slide Annotation System that employs a robust hybrid two-stage detector to identify slide boundaries, extracts slide text through Optical Character Recognition (OCR), transcribes narration, and employs a multimodal Large Language Model (LLM) to generate concise, context-aware annotations that are added to their corresponding slide locations. For evaluations, the technical performance was validated on five recorded presentations, while the user experience was assessed by 37 participants. The results showed that the system achieved a macro-average 𝐹1 score of 0.879 (𝑆𝐷=0.024, 95% 𝐶𝐼[0.849,0.909]) for slide segmentation and 90.0% accuracy (95% 𝐶𝐼[74.4%,96.5%]) for annotation alignment. Subjective evaluations revealed high annotation validity and usefulness as rated by presenters, and a high System Usability Scale (SUS) score of 80.5 (𝑆𝐷=6.7, 95% 𝐶𝐼[78.3,82.7]). Qualitative feedback further confirmed that the system effectively streamlined the review process, enabling users to locate key information more efficiently than standard video playback. These findings demonstrate the strong potential of the proposed system as an effective automated annotation system. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2078-2489 17 1 2026 An SQL Query Description Problem with AI Assistance for an SQL Programming Learning Assistant System 65 EN Ni Wayan Wardani Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Htoo Htoo Sandi Kyaw Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Zihao Zhu Graduate School of Environmental, Life, Natural Science and Technology, Okayama University I Nyoman Darma Kotama Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Putu Sugiartawan Graduate School of Environmental, Life, Natural Science and Technology, Okayama University I Nyoman Agus Suarya Putra Faculty of Business and Creative Design, Indonesian Institute of Business and Technology Today, relational databases are widely used in information systems. SQL (structured query language) is taught extensively in universities and professional schools across the globe as a programming language for its data management and accesses. Previously, we have studied a web-based programming learning assistant system (PLAS) to help novice students learn popular programming languages by themselves through solving various types of exercises. For SQL programming, we have implemented the grammar-concept understanding problem (GUP) and the comment insertion problem (CIP) for its initial studies. In this paper, we propose an SQL Query Description Problem (SDP) as a new exercise type for describing the SQL query to a specified request in a MySQL database system. To reduce teachers’ preparation workloads, we integrate a generative AI-assisted SQL query generator to automatically generate a new SDP instance with a given dataset. An SDP instance consists of a table, a set of questions and corresponding queries. Answer correctness is determined by enhanced string matching against an answer module that includes multiple semantically equivalent canonical queries. For evaluation, we generated 11 SDP instances on basic topics using the generator, where we found that Gemini 3.0 Pro exhibited higher pedagogical consistency compared to ChatGPT-5.0, achieving perfect scores in Sensibleness, Topicality, and Readiness metrics. Then, we assigned the generated instances to 32 undergraduate students at the Indonesian Institute of Business and Technology (INSTIKI). The results showed an average correct answer rate of 95.2% and a mean SUS score of 78, which demonstrates strong initial student performance and system acceptance. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2813-2203 5 1 2025 A Threshold Selection Method in Code Plagiarism Checking Function for Code Writing Problem in Java Programming Learning Assistant System Considering AI-Generated Codes 2 EN Perwira Annissa Dyah Permatasari Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Mustika Mentari Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Safira Adine Kinari Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Soe Thandar Aung Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Htoo Htoo Sandi Kyaw Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Khaing Hsu Wai Graduate School of Engineering Science, Akita University To support novice learners, the Java programming learning assistant system (JPLAS) has been developed with various features. Among them, code writing problem (CWP) assigns writing an answer code that passes a given test code. The correctness of an answer code is validated by running it on JUnit. In previous works, we implemented a code plagiarism checking function that calculates the similarity score for each pair of answer codes based on the Levenshtein distance. When the score is higher than a given threshold, this pair is regarded as plagiarism. However, a method for finding the proper threshold has not been studied. In addition, AI-generated codes have become threats in plagiarism, as AI has grown in popularity, which should be investigated. In this paper, we propose a threshold selection method based on Tukey’s IQR fences. It uses a custom upper threshold derived from the statistical distribution of similarity scores for each assignment. To better accommodate skewed similarity distributions, the method introduces a simple percentile-based adjustment for determining the upper threshold. We also design prompts to generate answer codes using generative AI and apply them to four AI models. For evaluation, we used a total of 745 source codes of two datasets. The first dataset consists of 420 answer codes across 12 CWP instances from 35 first-year undergraduate students in the State Polytechnic of Malang, Indonesia (POLINEMA). The second dataset includes 325 answer codes across five CWP assignments from 65 third-year undergraduate students at Okayama University, Japan. The applications of our proposals found the following: (1) any pair of student codes whose score is higher than the selected threshold has some evidence of plagiarism, (2) some student codes have a higher similarity than the threshold with AI-generated codes, indicating the use of generative AI, and (3) multiple AI models can generate code that resembles student-written code, despite adopting different implementations. The validity of our proposal is confirmed. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2079-9292 14 24 2025 An AI-Driven System for Learning MQTT Communication Protocols with Python Programming 4967 EN Zihao Zhu Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University I Nyoman Darma Kotama Department of Information and Communication Systems, Okayama University Anak Agung Surya Pradhana Department of Information and Communication Systems, Okayama University Alfiandi Aulia Rahmadani Department of Information and Communication Systems, Okayama University Noprianto Department of Information and Communication Systems, Okayama University With rapid developments of wireless communication and Internet of Things (IoT) technologies, an increasing number of devices and sensors are interconnected, generating massive amounts of data in real time. Among the underlying protocols, Message Queuing Telemetry Transport (MQTT) has become a widely adopted lightweight publish–subscribe standard due to its simplicity, minimal overhead, and scalability. Then, understanding such protocols is essential for students and engineers engaging in IoT application system designs. However, teaching and learning MQTT remains challenging for them. Its asynchronous architecture, hierarchical topic structure, and constituting concepts such as retained messages, Quality of Service (QoS) levels, and wildcard subscriptions are often difficult for beginners. Moreover, traditional learning resources emphasize theory and provide limited hands-on guidance, leading to a steep learning curve. To address these challenges, we propose an AI-assisted, exercise-based learning platform for MQTT. This platform provides interactive exercises with intelligent feedback to bridge the gap between theory and practice. To lower the barrier for learners, all code examples for executing MQTT communication are implemented in Python for readability, and Docker is used to ensure portable deployments of the MQTT broker and AI assistant. For evaluations, we conducted a usability study using two groups. The first group, who has no prior experience, focused on fundamental concepts with AI-guided exercises. The second group, who has relevant background, engaged in advanced projects to apply and reinforce their knowledge. The results show that the proposed platform supports learners at different levels, reduces frustrations, and improves both engagement and efficiency. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2078-2489 16 10 2025 A Comparative Study of Authoring Performances Between In-Situ Mobile and Desktop Tools for Outdoor Location-Based Augmented Reality 908 EN Komang Candra Brata Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University Prismahardi Aji Riyantoko Department of Information and Communication Systems, Okayama University Noprianto Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University In recent years, Location-Based Augmented Reality (LAR) systems have been increasingly implemented in various applications for tourism, navigation, education, and entertainment. Unfortunately, the LAR content creation using conventional desktop-based authoring tools has become a bottleneck, as it requires time-consuming and skilled work. Previously, we proposed an in-situ mobile authoring tool as an efficient solution to this problem by offering direct authoring interactions in real-world environments using a smartphone. Currently, the evaluation through the comparison between the proposal and conventional ones is not sufficient to show superiority, particularly in terms of interaction, authoring performance, and cognitive workload, where our tool uses 6DoF device movement for spatial input, while desktop ones rely on mouse-pointing. In this paper, we present a comparative study of authoring performances between the tools across three authoring phases: (1) Point of Interest (POI) location acquisition, (2) AR object creation, and (3) AR object registration. For the conventional tool, we adopt Unity and ARCore SDK. As a real-world application, we target the LAR content creation for pedestrian landmark annotation across campus environments at Okayama University, Japan, and Brawijaya University, Indonesia, and identify task-level bottlenecks in both tools. In our experiments, we asked 20 participants aged 22 to 35 with different LAR development experiences to complete equivalent authoring tasks in an outdoor campus environment, creating various LAR contents. We measured task completion time, phase-wise contribution, and cognitive workload using NASA-TLX. The results show that our tool made faster creations with 60% lower cognitive loads, where the desktop tool required higher mental efforts with manual data input and object verifications. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2078-2489 16 1 2025 Relay Node Selection Methods for UAV Navigation Route Constructions in Wireless Multi-Hop Network Using Smart Meter Devices 22 EN Shuto Ohkawa Graduate School of Engineering, Nihon University Kiyoshi Ueda Graduate School of Engineering, Nihon University Takumi Miyoshi College of Systems Engineering and Science, Shibaura Institute of Technology Taku Yamazaki College of Systems Engineering and Science, Shibaura Institute of Technology Ryo Yamamoto Graduate School of Informatics and Engineering, The University of Electro-Communications Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Unmanned aerial vehicles (UAVs) offer solutions to issues like traffic congestion and labor shortages. We developed a distributed UAV management system inspired by virtual circuit and datagram methods in packet-switching networks. By installing houses with wireless terminals, UAVs navigate routes in a multi-hop network, communicating with ground nodes. UAVs are treated as network packets, ground devices are treated as routers, and their connections are treated as links. Activating all nodes as relays increases control message traffic and node load. To optimize connectivity, we minimize relay nodes, connecting non-relay nodes to the nearest relay. This study proposes four relay node selection methods: random selection, two adjacency-based methods, and our innovative approach using Multipoint Relay (MPR) from the Optimized Link State Routing Protocol (OLSR). We evaluated these methods according to their route construction success rates, relay node counts, route lengths, and so on. The MPR-based method proved most effective for UAV route construction. However, fewer relay nodes increase link collisions, and we identify the minimum relay density needed to balance efficiency and conflict reduction. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2073-431X 14 10 2025 A Guided Self-Study Platform of Integrating Documentation, Code, Visual Output, and Exercise for Flutter Cross-Platform Mobile Programming 417 EN Safira Adine Kinari Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Soe Thandar Aung Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Information and Communication Systems, Okayama University Nowadays, Flutter with the Dart programming language has become widely popular in mobile developments, allowing developers to build multi-platform applications using one codebase. An increasing number of companies are adopting these technologies to create scalable and maintainable mobile applications. Despite this increasing relevance, university curricula often lack structured resources for Flutter/Dart, limiting opportunities for students to learn it in academic environments. To address this gap, we previously developed the Flutter Programming Learning Assistance System (FPLAS), which supports self-learning through interactive problems focused on code comprehension through code-based exercises and visual interfaces. However, it was observed that many students completed the exercises without fully understanding even basic concepts, if they already had some knowledge of object-oriented programming (OOP). As a result, they may not be able to design and implement Flutter/Dart codes independently, highlighting a mismatch between the system’s outcomes and intended learning goals. In this paper, we propose a guided self-study approach of integrating documentation, code, visual output, and exercise in FPLAS. Two existing problem types, namely, Grammar Understanding Problems (GUP) and Element Fill-in-Blank Problems (EFP), are combined together with documentation, code, and output into a new format called Integrated Introductory Problems (INTs). For evaluations, we generated 16 INT instances and conducted two rounds of evaluations. The first round with 23 master students in Okayama University, Japan, showed high correct answer rates but low usability ratings. After revising the documentation and the system design, the second round with 25 fourth-year undergraduate students in the same university demonstrated high usability and consistent performances, which confirms the effectiveness of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2624-831X 6 3 2025 An Extension of Input Setup Assistance Service Using Generative AI to Unlearned Sensors for the SEMAR IoT Application Server Platform 52 EN I Nyoman Darma Kotama Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Yohanes Yohanie Fridelin Panduman Graduate School of Information Science and Technology, The University of Osaka Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University Anak Agung Surya Pradhana Graduate School of Natural Science and Technology, Okayama University Noprianto Graduate School of Natural Science and Technology, Okayama University Nowadays, Internet of Things (IoT) application systems are broadly applied to various sectors of society for efficient management by monitoring environments using sensors, analyzing sampled data, and giving proper feedback. For their fast deployment, we have developed Smart Environmental Monitoring and Analysis in Real Time (SEMAR) as an integrated IoT application server platform and implemented the input setup assistance service using prompt engineering and a generative AI model to assist connecting sensors to SEMAR with step-by-step guidance. However, the current service cannot assist in connections of the sensors not learned by the AI model, such as newly released ones. To address this issue, in this paper, we propose an extension to the service for handling unlearned sensors by utilizing datasheets with four steps: (1) users input a PDF datasheet containing information about the sensor, (2) key specifications are extracted from the datasheet and structured into markdown format using a generative AI, (3) this data is saved to a vector database using chunking and embedding methods, and (4) the data is used in Retrieval-Augmented Generation (RAG) to provide additional context when guiding users through sensor setup. Our evaluation with five generative AI models shows that OpenAI’s GPT-4o achieves the highest accuracy in extracting specifications from PDF datasheets and the best answer relevancy (0.987), while Gemini 2.0 Flash delivers the most balanced results, with the highest overall RAGAs score (0.76). Other models produced competitive but mixed outcomes, averaging 0.74 across metrics. The step-by-step guidance function achieved a task success rate above 80%. In a course evaluation by 48 students, the system improved the student test scores, further confirming the effectiveness of our proposed extension. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2078-2489 16 7 2025 A Fundamental Statistics Self-Learning Method with Python Programming for Data Science Implementations 607 EN Prismahardi Aji Riyantoko Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Komang Candra Brata Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University Aviolla Terza Damaliana Department of Data Science, Universitas Pembangunan Nasional Veteran Jawa Timur Dwi Arman Prasetya Department of Data Science, Universitas Pembangunan Nasional Veteran Jawa Timur The increasing demand for data-driven decision making to maintain the innovations and competitiveness of organizations highlights the need for data science educations across academia and industry. At its core is a solid understanding of statistics, which is necessary for conducting a thorough analysis of data and deriving valuable insights. Unfortunately, conventional statistics learning often lacks practice in real-world applications using computer programs, causing a separation between conceptual knowledge of statistics equations and their hands-on skills. Integrating statistics learning into Python programming can convey an effective solution for this problem, where it has become essential in data science implementations, with extensive and versatile libraries. In this paper, we present a self-learning method for fundamental statistics through Python programming for data science studies. Unlike conventional approaches, our method integrates three types of interactive problems—element fill-in-blank problem (EFP), grammar-concept understanding problem (GUP), and value trace problem (VTP)—in the Programming Learning Assistant System (PLAS). This combination allows students to write code, understand concepts, and trace the output value while obtaining instant feedback so that they can improve retention, knowledge, and practical skills in learning statistics using Python programming. For evaluations, we generated 22 instances using source codes for fundamental statistics topics, and assigned them to 40 first-year undergraduate students at UPN Veteran Jawa Timur, Indonesia. Statistics analytical methods were utilized to analyze the student learning performances. The results show that a significant correlation (𝜌<0.05) exists between the students who solved our proposal and those who did not. The results confirm that it can effectively assist students in learning fundamental statistics self-learning using Python programming for data science implementations. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2078-2489 16 7 2025 A Map Information Collection Tool for a Pedestrian Navigation System Using Smartphone 588 EN Kadek Suarjuna Batubulan Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University I Nyoman Darma Kotama Graduate School of Natural Science and Technology, Okayama University Htoo Htoo Sandi Kyaw Graduate School of Natural Science and Technology, Okayama University Shintami Chusnul Hidayati Department of Informatics, Institut Teknologi Sepuluh Nopember Nowadays, a pedestrian navigation system using a smartphone has become popular as a useful tool to reach an unknown destination. When the destination is the office of a person, a detailed map information is necessary on the target area such as the room number and location inside the building. The information can be collected from various sources including Google maps, websites for the building, and images of signs. In this paper, we propose a map information collection tool for a pedestrian navigation system. To improve the accuracy and completeness of information, it works with the four steps: (1) a user captures building and room images manually, (2) an OCR software using Google ML Kit v2 processes them to extract the sign information from images, (3) web scraping using Scrapy (v2.11.0) and crawling with Apache Nutch (v1.19) software collects additional details such as room numbers, facilities, and occupants from relevant websites, and (4) the collected data is stored in the database to be integrated with a pedestrian navigation system. For evaluations of the proposed tool, the map information was collected for 10 buildings at Okayama University, Japan, a representative environment combining complex indoor layouts (e.g., interconnected corridors, multi-floor facilities) and high pedestrian traffic, which are critical for testing real-world navigation challenges. The collected data is assessed in completeness and effectiveness. A university campus was selected as it presents a complex indoor and outdoor environment that can be ideal for testing pedestrian navigations in real-world scenarios. With the obtained map information, 10 users used the navigation system to successfully reach destinations. The System Usability Scale (SUS) results through a questionnaire confirms the high usability. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2079-9292 14 11 2025 An Automatic Code Generation Tool Using Generative Artificial Intelligence for Element Fill-in-the-Blank Problems in a Java Programming Learning Assistant System 2261 EN Zihao Zhu Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University Soe Thandar Aung Department of Information and Communication Systems, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Yi-Fang Lee Department of Industrial Education, National Taiwan Normal University Presently, Java is a fundamental object-oriented programming language that can be mastered by any student in information technology or computer science. To assist both teachers and students, we developed the Java Programming Learning Assistant System (JPLAS). It offers several types of practice problems with different levels and learning goals for step-by-step self-study, where any answer is automatically marked in the system. One challenge for teachers that is addressed with JPLAS is the generation of proper exercise problems that meet learning requirements. We implemented programs for generating new problems from given source codes, as collecting and evaluating suitable codes remains time-consuming. In this paper, we present an automatic code generation tool using generative AI to solve this challenge. Prompt engineering is used to help generate an appropriate source code, and the quality is controlled by optimizing the prompt based on the outputs. For applications in JPLAS, we implement a web application system to automatically generate an element fill-in-the-blank problem (EFP) in JPLAS. For evaluation, we select the element fill-in-the-blank problem (EFP) as the target type in JPLAS and generate several instances using this tool. The results confirm the validity and effectiveness of the proposed method. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 1999-5903 17 8 2025 A Verilog Programming Learning Assistant System Focused on Basic Verilog with a Guided Learning Method 333 EN Pin-Chieh Hsieh Department of Electronic Engineering, National Taipei University of Technology Tzu-Lun Fang Department of Electronic Engineering, National Taipei University of Technology Shaobo Jin Department of Information and Communication Systems, Okayama University Yuyan Wang Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Yu-Cheng Fan Department of Electronic Engineering, National Taipei University of Technology With continuous advancements in semiconductor technology, mastering efficient designs of high-quality and advanced chips has become an important part of science and technology education. Chip performances will determine the futures of various aspects of societies. However, novice students often encounter difficulties in learning digital chip designs using Verilog programming, a common hardware design language. An efficient self-study system for supporting them that can offer various exercise problems, such that any answer is marked automatically, is in strong demand. In this paper, we design and implement a web-based Verilog programming learning assistant system (VPLAS), based on our previous works on software programming. Using a heuristic and guided learning method, VPLAS leads students to learn the basic circuit syntax step by step, until they acquire high-quality digital integrated circuit design abilities through self-study. For evaluation, we assign the proposal to 50 undergraduate students at the National Taipei University of Technology, Taiwan, who are taking the introductory chip-design course, and confirm that their learning outcomes using VPLAS together are far better than those obtained when following a traditional method. In our final statistics, students achieved an average initial accuracy rate of over 70% on their first attempts at answering questions after learning through our website’s tutorials. With the help of the system’s instant automated grading and rapid feedback, their average accuracy rate eventually exceeded 99%. This clearly demonstrates tha No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 1999-5903 17 5 2025 An Improved Reference Paper Collection System Using Web Scraping with Three Enhancements 195 EN Tresna Maulana Fahrudin Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Komang Candra Brata Department of Information and Communication Systems, Okayama University Inzali Naing Department of Information and Communication Systems, Okayama University Soe Thandar Aung Department of Information and Communication Systems, Okayama University Amri Muhaimin Department of Data Science, Universitas Pembangunan Nasional Veteran Jawa Timur Dwi Arman Prasetya Department of Data Science, Universitas Pembangunan Nasional Veteran Jawa Timur Nowadays, accessibility to academic papers has been significantly improved with electric publications on the internet, where open access has become common. At the same time, it has increased workloads in literature surveys for researchers who usually manually download PDF files and check their contents. To solve this drawback, we have proposed a reference paper collection system using a web scraping technology and natural language models. However, our previous system often finds a limited number of relevant reference papers after taking long time, since it relies on one paper search website and runs on a single thread at a multi-core CPU. In this paper, we present an improved reference paper collection system with three enhancements to solve them: (1) integrating the APIs from multiple paper search web sites, namely, the bulk search endpoint in the Semantic Scholar API, the article search endpoint in the DOAJ API, and the search and fetch endpoint in the PubMed API to retrieve article metadata, (2) running the program on multiple threads for multi-core CPU, and (3) implementing Dynamic URL Redirection, Regex-based URL Parsing, and HTML Scraping with URL Extraction for fast checking of PDF file accessibility, along with sentence embedding to assess relevance based on semantic similarity. For evaluations, we compare the number of obtained reference papers and the response time between the proposal, our previous work, and common literature search tools in five reference paper queries. The results show that the proposal increases the number of relevant reference papers by 64.38% and reduces the time by 59.78% on average compared to our previous work, while outperforming common literature search tools in reference papers. Thus, the effectiveness of the proposed system has been demonstrated in our experiments. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2227-7080 13 4 2025 An Implementation of Creep Test Assisting System with Dial Gauge Needle Reading and Smart Lighting Function for Laboratory Automation 139 EN Dezheng Kong Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Shihao Fang Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Noprianto Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Mitsuhiro Okayasu Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Pradini Puspitaningayu Department of Electrical Engineering, Universitas Negeri Surabaya For decades, analog dial gauges have been essential for measuring and monitoring data at various industrial instruments including production machines and laboratory equipment. Among them, we focus on the instrument for creep test in a mechanical engineering laboratory, which evaluates material strength under sustained stress. Manual reading of gauges imposes significant labor demands, especially in long-duration tests. This burden further increases under low-lighting environments, where poor visibility can lead to misreading data points, potentially compromising the accuracy of test results. In this paper, to address the challenges, we implement a creep test assisting system that possesses the following features: (1) to save the installation cost, a web camera and Raspberry Pi are employed to capture images of the dial gauge and automate the needle reading by image processing in real time, (2) to ensure reliability under low-lighting environments, a smart lighting mechanism is integrated to turn on a supplementary light when the dial gauge is not clearly visible, and (3) to allow a user to stay in a distant place from the instrument during a creep test, material break is detected and the corresponding message is notified to a laboratory staff using LINE automatically. For evaluations, we install the implemented system into a material strength measuring instrument at Okayama University, Japan, and confirm the effectiveness and accuracy through conducting experiments under various lighting conditions. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2227-7080 13 4 2025 An Implementation of Creep Test Assisting System with Dial Gauge Needle Reading and Smart Lighting Function for Laboratory Automation 139 EN Dezheng Kong Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Shihao Fang Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Mitsuhiro Noprianto Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Mitsuhiro Okayasu Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Pradini Puspitaningayu Department of Electrical Engineering, Universitas Negeri Surabaya For decades, analog dial gauges have been essential for measuring and monitoring data at various industrial instruments including production machines and laboratory equipment. Among them, we focus on the instrument for creep test in a mechanical engineering laboratory, which evaluates material strength under sustained stress. Manual reading of gauges imposes significant labor demands, especially in long-duration tests. This burden further increases under low-lighting environments, where poor visibility can lead to misreading data points, potentially compromising the accuracy of test results. In this paper, to address the challenges, we implement a creep test assisting system that possesses the following features: (1) to save the installation cost, a web camera and Raspberry Pi are employed to capture images of the dial gauge and automate the needle reading by image processing in real time, (2) to ensure reliability under low-lighting environments, a smart lighting mechanism is integrated to turn on a supplementary light when the dial gauge is not clearly visible, and (3) to allow a user to stay in a distant place from the instrument during a creep test, material break is detected and the corresponding message is notified to a laboratory staff using LINE automatically. For evaluations, we install the implemented system into a material strength measuring instrument at Okayama University, Japan, and confirm the effectiveness and accuracy through conducting experiments under various lighting conditions. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1999-4893 18 3 2025 A Hair Drawing Evaluation Algorithm for Exactness Assessment Method in Portrait Drawing Learning Assistant System 143 EN Yue Zhang Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Erita Cicilia Febrianti Department of Electrical Engineering, Politeknik Elektronika Negeri Surabaya Amang Sudarsono Department of Electrical Engineering, Politeknik Elektronika Negeri Surabaya Chenchien Hsu Department of Electrical Engineering, National Taiwan Normal University Nowadays, portrait drawing has become increasingly popular as a means of developing artistic skills and nurturing emotional expression. However, it is challenging for novices to start learning it, as they usually lack a solid grasp of proportions and structural foundations of the five senses. To address this problem, we have studied Portrait Drawing Learning Assistant System (PDLAS) for guiding novices by providing auxiliary lines of facial features, generated by utilizing OpenPose and OpenCV libraries. For PDLAS, we have also presented the exactness assessment method to evaluate drawing accuracy using the Normalized Cross-Correlation (NCC) algorithm. It calculates the similarity score between the drawing result and the initial portrait photo. Unfortunately, the current method does not assess the hair drawing, although it occupies a large part of a portrait and often determines its quality. In this paper, we present a hair drawing evaluation algorithm for the exactness assessment method to offer comprehensive feedback to users in PDLAS. To emphasize hair lines, this algorithm extracts the texture of the hair region by computing the eigenvalues and eigenvectors of the hair image. For evaluations, we applied the proposal to drawing results by seven students from Okayama University, Japan and confirmed the validity. In addition, we observed the NCC score improvement in PDLAS by modifying the face parts with low similarity scores from the exactness assessment method. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 16 2 2025 Implementation of Sensor Input Setup Assistance Service Using Generative AI for SEMAR IoT Application Server Platform 108 EN I. Nyoman Darma Kotama Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University Anak Agung Surya Pradhana Graduate School of Natural Science and Technology, Okayama University Noprianto Graduate School of Natural Science and Technology, Okayama University I. Gusti Made Ngurah Desnanjaya Department of Computer System Engineering, Institute of Business and Technology Indonesia For rapid deployments of various IoT application systems, we have developed Smart Environmental Monitoring and Analytical in Real-Time (SEMAR) as an integrated server platform. It is equipped with rich functions for collecting, analyzing, and visualizing various data. Unfortunately, the proper configuration of SEMAR with a variety of IoT devices can be complex and challenging for novice users, since it often requires technical expertise. The assistance of Generative AI can be helpful to solve this drawback. In this paper, we present an implementation of a sensor input setup assistance service for SEMAR using prompt engineering techniques and Generative AI. A user needs to define the requirement specifications and environments of the IoT application system for sensor inputs, and give them to the service. Then, the service provides step-by-step guidance on sensor connections, communicating board configurations, network connections, and communication protocols to the user, which can help the user easily set up the configuration to connect the relevant devices to SEMAR. For evaluations, we applied the proposal to the input sensor setup processes of three practical IoT application systems with SEMAR, namely, a smart light, water heater, and room temperature monitoring system. In addition, we applied it to the setup process of an IoT application system for a course for undergraduate students at the Insitut Bisnis dan Teknologi (INSTIKI), Indonesia. The results demonstrate the effectiveness of the proposed service for SEMAR. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 16 2 2025 An Application of SEMAR IoT Application Server Platform to Drone-Based Wall Inspection System Using AI Model 91 EN Yohanes Yohanie Fridelin Panduman Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Radhiatul Husna Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Noprianto Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Shunya Sakamaki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatics and Computer, Politeknik Elektronika Negeri Surabaya Yan Watequlis Syaifudin Department of Information Technology, State Polytechnic of Malang Alfiandi Aulia Rahmadani Department of Electrical Engineering, State Polytechnic of Malang Recently, artificial intelligence (AI) has been adopted in a number of Internet of Things (IoT) application systems to enhance intelligence. We have developed a ready-made server with rich built-in functions to collect, process, display, analyze, and store data from various IoT devices, the SEMAR (Smart Environmental Monitoring and Analytics in Real-Time) IoT application server platform, in which various AI techniques have been implemented to enhance its capabilities. In this paper, we present an application of SEMAR to a drone-based wall inspection system using an object detection AI model called You Only Look Once (YOLO). This system aims to detect wall cracks at high places using images taken via a camera on a flying drone. An edge computing device is installed to control the drone, sending the taken images through the Kafka system, storing them with the drone flight data, and sending the data to SEMAR. The images are analyzed via YOLO through SEMAR. For evaluations, we implemented the system using Ryze Tello for the drone and Raspberry Pi for the edge, and we evaluated the detection accuracy. The preliminary experiment results confirmed the effectiveness of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2224-2708 14 1 2024 Enhancing Campus Environment: Real-Time Air Quality Monitoring Through IoT and Web Technologies 2 EN Alfiandi Aulia Rahmadani Department of Electrical Engineering, State Polytechnic of Malang Yan Watequlis Syaifudin Department of Information Technology, State Polytechnic of Malang Budhy Setiawan Department of Electrical Engineering, State Polytechnic of Malang Yohanes Yohanie Fridelin Panduman Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Nowadays, enhancing campus environments through mitigations of air pollutions is an essential endeavor to support academic achievements, health, and safety of students and staffs in higher educational institutes. In laboratories, pollutants from welding, auto repairs, or chemical experiments can drastically degrade the air quality in the campus, endangering the respiratory and cognitive health of students and staffs. Besides, in universities in Indonesia, automobile emissions of harmful substances such as carbon monoxide (CO), nitrogen dioxide (NO2), and hydrocarbon (HC) have been a serious problem for a long time. Almost everybody is using a motorbike or a car every day in daily life, while the number of students is continuously increasing. However, people in many campuses including managements do not be aware these problems, since air quality is not monitored. In this paper, we present a real-time air quality monitoring system utilizing Internet of Things (IoT) integrated sensors capable of detecting pollutants and measuring environmental conditions to visualize them. By transmitting data to the SEMAR IoT application server platform via an ESP32 microcontroller, this system provides instant alerts through a web application and Telegram notifications when pollutant levels exceed safe thresholds. For evaluations of the proposed system, we adopted three sensors to measure the levels of CO, NO2, and HC and conducted experiments in three sites, namely, Mechatronics Laboratory, Power and Emission Laboratory, and Parking Lot, at the State Polytechnic of Malang, Indonesia. Then, the results reveal Good, Unhealthy, and Dangerous for them, respectively, among the five categories defined by the Indonesian government. The system highlighted its ability to monitor air quality fluctuations, trigger warnings of hazardous conditions, and inform the campus community. The correlation of the sensor levels can identify the relationship of each pollutant, which provides insight into the characteristics of pollutants in a particular scenario. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2073-431X 14 1 2025 An Investigation of Hand Gestures for Controlling Video Games in a Rehabilitation Exergame System 25 EN Radhiatul Husna Department of Information and Communication Systems, Okayama University Komang Candra Brata Department of Information and Communication Systems, Okayama University Irin Tri Anggraini Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Alfiandi Aulia Rahmadani Department of Electrical Engineering, State Polytechnic of Malang Chih-Peng Fan Department of Electrical Engineering, National Chung Hsing University Musculoskeletal disorders (MSDs) can significantly impact individuals' quality of life (QoL), often requiring effective rehabilitation strategies to promote recovery. However, traditional rehabilitation methods can be expensive and may lack engagement, leading to poor adherence to therapy exercise routines. An exergame system can be a solution to this problem. In this paper, we investigate appropriate hand gestures for controlling video games in a rehabilitation exergame system. The Mediapipe Python library is adopted for the real-time recognition of gestures. We choose 10 easy gestures among 32 possible simple gestures. Then, we specify and compare the best and the second-best groups used to control the game. Comprehensive experiments are conducted with 16 students at Andalas University, Indonesia, to find appropriate gestures and evaluate user experiences of the system using the System Usability Scale (SUS) and User Experience Questionnaire (UEQ). The results show that the hand gestures in the best group are more accessible than in the second-best group. The results suggest appropriate hand gestures for game controls and confirm the proposal's validity. In future work, we plan to enhance the exergame system by integrating a diverse set of video games, while expanding its application to a broader and more diverse sample. We will also study other practical applications of the hand gesture control function. No potential conflict of interest relevant to this article was reported.

MDPI AG Acta Medica Okayama 2079-9292 14 2 2025 A Proposal of In Situ Authoring Tool with Visual-Inertial Sensor Fusion for Outdoor Location-Based Augmented Reality 342 EN Komang Candra Brata Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Yohanes Yohanie Fridelin Panduman Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University Yan Watequlis Syaifudin Department of Information Technology, Politeknik Negeri Malang Alfiandi Aulia Rahmadani Department of Information Technology, Politeknik Negeri Malang In location-based augmented reality (LAR) applications, a simple and effective authoring tool is essential to create immersive AR experiences in real-world contexts. Unfortunately, most of the current tools are primarily desktop-based, requiring manual location acquisitions, the use of software development kits (SDKs), and high programming skills, which poses significant challenges for novice developers and a lack of precise LAR content alignment. In this paper, we propose an intuitive in situ authoring tool with visual-inertial sensor fusions to simplify the LAR content creation and storing process directly using a smartphone at the point of interest (POI) location. The tool localizes the user’s position using smartphone sensors and maps it with the captured smartphone movement and the surrounding environment data in real-time. Thus, the AR developer can place a virtual object on-site intuitively without complex programming. By leveraging the combined capabilities of Visual Simultaneous Localization and Mapping(VSLAM) and Google Street View (GSV), it enhances localization and mapping accuracy during AR object creation. For evaluations, we conducted extensive user testing with 15 participants, assessing the task success rate and completion time of the tool in practical pedestrian navigation scenarios. The Handheld Augmented Reality Usability Scale (HARUS) was used to evaluate overall user satisfaction. The results showed that all the participants successfully completed the tasks, taking 16.76 s on average to create one AR object in a 50 m radius area, while common desktop-based methods in the literature need 1–8 min on average, depending on the user’s expertise. Usability scores reached 89.44 for manipulability and 85.14 for comprehensibility, demonstrating the high effectiveness in simplifying the outdoor LAR content creation process. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2079-9292 13 24 2024 An Implementation of Web-Based Answer Platform in the Flutter Programming Learning Assistant System Using Docker Compose 4878 EN Lynn Htet Aung Department of Information and Communication Systems, Okayama University Soe Thandar Aung Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Htoo Htoo Sandi Kyaw Department of Computer and Information Science, Tokyo University of Agriculture and Technology Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Programming has gained significant importance worldwide as societies increasingly rely on computer application systems. To support novices in learning various programming languages, we have developed the Programming Learning Assistant System (PLAS). It offers several types of exercise problems with different learning goals and levels for step-by-step self-study. As a personal answer platform in PLAS, we have implemented a web application using Node.js and EJS for Java and Python programming. Recently, the Flutter framework with Dart programming has become popular, enabling developers to build applications for mobile, web, and desktop environments from a single codebase. Thus, we have extended PLAS by implementing the Flutter environment with Visual Studio Code to support it. Additionally, we have developed an image-based user interface (UI) testing tool to verify student source code by comparing its generated UI image with the standard one using the ORB and SIFT algorithms in OpenCV. For efficient distribution to students, we have generated Docker images of the answer platform, Flutter environment, and image-based UI testing tool. In this paper, we present the implementation of a web-based answer platform for the Flutter Programming Learning Assistant System (FPLAS) by integrating three Docker images using Docker Compose. Additionally, to capture UI images automatically, an Nginx web application server is adopted with its Docker image. For evaluations, we asked 10 graduate students at Okayama University, Japan, to install the answer platform on their PCs and solve five exercise problems. All the students successfully completed the problems, which confirms the validity and effectiveness of the proposed system. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 12 2024 A Yoga Pose Difficulty Level Estimation Method Using OpenPose for Self-Practice System to Yoga Beginners 789 EN Cheng-Liang Shih Department of Electrical Engineering, National Chung Hsing University Jun-You Liu Department of Electrical Engineering, National Chung Hsing University Irin Tri Anggraini Department of Electrical and Communication Engineering, Okayama University Yanqi Xiao Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Chih-Peng Fan Department of Electrical Engineering, National Chung Hsing University Yoga is an exercise preferable for various users at different ages to enhance physical and mental health. To help beginner yoga self-practitioners avoid getting injured by selecting difficult yoga poses, the information of the difficulty level of yoga poses is very important to provide an objective metric to assist yoga self-practitioners in selecting appropriate exercises on the basis of their skill level by using the yoga self-practice system. To enhance the developed yoga self-practice system, the yoga difficulty level estimation function will enable users to clearly understand whether the selected yoga poses are suitable for them. In this paper, the newest difficulty level estimation method of yoga poses is proposed by using and analyzing OpenPose two-dimensional (2D) human body keypoints. The proposed method effectively uses the selected six keypoints areas of the upper and lower body, body support types, center of gravity calculations, and body tilt angles and slopes to produce estimations. Firstly, the method calculates the weighted centers of the upper and lower human body for each pose by using keypoints. Secondly, it refers the slope of the centroid line between the two centers and infers the body's balance state. Lastly, the system estimates the difficulty level by additionally considering the keypoints of the body to contact the ground. For evaluations of the proposal, more than one hundred yoga poses are collected from the Internet and applied to classify them into five difficulty levels. Through comparisons with subjective levels from one instructor and 10 users, the validity of the estimation results is confirmed, a comparison is performed with existing designs, and it is implemented in embedded systems. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 10 2024 A Study of Exergame System Using Hand Gestures for Wrist Flexibility Improvement for Tenosynovitis Prevention 622 EN Yanqi Xiao Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Irin Tri Anggraini Department of Information and Communication Systems, Okayama University Cheng-Liang Shih Department of Information and Communication Systems, Okayama University Chih-Peng Fan Department of Information and Communication Systems, Okayama University Currently, as an increasing number of people have been addicted to using cellular phones, smartphone tenosynovitis has become common from long-term use of fingers for their operations. Hand exercise while playing video games, which is called exergame, can be a good solution to provide enjoyable daily exercise opportunities for its prevention, particularly, for young people. In this paper, we implemented a simple exergame system with a hand gesture recognition program made in Python using the Mediapipe library. We designed three sets of hand gestures to control the key operations to play the games as different exercises useful for tenosynovitis prevention. For evaluations, we prepared five video games running on a web browser and asked 10 students from Okayama and Hiroshima Universities, Japan, to play them and answer 10 questions in the questionnaire. Their playing results and System Usability Scale (SUS) scores confirmed the usability of the proposal, although we improved one gesture set to reduce its complexity. Moreover, by measuring the angles for maximum wrist movements, we found that the wrist flexibility was improved by playing the games, which verifies the effectiveness of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 10 2024 An Independent Learning System for Flutter Cross-Platform Mobile Programming with Code Modification Problems 614 EN Safira Adine Kinari Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Soe Thandar Aung Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Khaing Hsu Wai Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Mustika Mentari Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Pradini Puspitaningayu Department of Electrical Engineering, Universitas Negeri Surabaya Nowadays, with the common use of smartphones in daily lives, mobile applications have become popular around the world, which will lead to a rise in Flutter framework. Developed by Google, Flutter with Dart programming provides a cross-platform development environment to create visually appealing and responsive user interfaces across mobile, web, and desktop platforms using a single codebase. However, due to time and staff limitations, the Flutter/Dart programming course is not included in curricula, even in IT departments in universities. Therefore, independent learning environments for students are essential to meet this growing popularity. Previously, we have developed programming learning assistant system (PLAS) as a web-browser-based self-learning platform for novice students. PLAS offers various types of exercise problems designed to cultivate programming skills step-by-step through a lot of code reading and code writing practices. Among them, one particular type is the code modification problem (CMP), which asks to modify the given source code to satisfy the new specifications. CMP is expected to be solved by novices with little effort if they have knowledge of other programming languages. Thus, PLAS with CMP will be an excellent platform for independent learning. In this paper, we present PLAS with CMP for the independent learning of Flutter/Dart programming. To improve the readability of the source code by students, we provided rich comments on grammar or behaviors. Besides, the code can be downloaded so that students can check and run it on an IDE. For evaluations, we generated 38 CMP instances for basic and multimedia/storage topics in Flutter/Dart programming and assigned them to 21 master students at Okayama University, Japan, who have never studied it. The results confirm the validity of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2673-8732 4 3 2024 A User Location Reset Method through Object Recognition in Indoor Navigation System Using Unity and a Smartphone (INSUS) 295 312 EN Evianita Dewi Fajrianti Graduate School of Natural Science and Technology, Okayama University Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Amma Liesvarastranta Haz Graduate School of Natural Science and Technology, Okayama University Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya To enhance user experiences of reaching destinations in large, complex buildings, we have developed a indoor navigation system using Unity and a smartphone called INSUS. It can reset the user location using a quick response (QR) code to reduce the loss of direction of the user during navigation. However, this approach needs a number of QR code sheets to be prepared in the field, causing extra loads at implementation. In this paper, we propose another reset method to reduce loads by recognizing information of naturally installed signs in the field using object detection and Optical Character Recognition (OCR) technologies. A lot of signs exist in a building, containing texts such as room numbers, room names, and floor numbers. In the proposal, the Sign Image is taken with a smartphone, the sign is detected by YOLOv8, the text inside the sign is recognized by PaddleOCR, and it is compared with each record in the Room Database using Levenshtein distance. For evaluations, we applied the proposal in two buildings in Okayama University, Japan. The results show that YOLOv8 achieved mAP@0.5 0.995 and mAP@0.5:0.95 0.978, and PaddleOCR could extract text in the sign image accurately with an averaged CER% lower than 10%. The combination of both YOLOv8 and PaddleOCR decreases the execution time by 6.71s compared to the previous method. The results confirmed the effectiveness of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2073-431X 13 9 2024 A Study of a Drawing Exactness Assessment Method Using Localized Normalized Cross-Correlations in a Portrait Drawing Learning Assistant System 215 EN Yue Zhang Graduate School of Environmental, Life, Natural Sciences and Technology, Okayama University Zitong Kong Graduate School of Environmental, Life, Natural Sciences and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Sciences and Technology, Okayama University Chen-Chien Hsu Department of Electrical Engineering, National Taiwan Normal University Nowadays, portrait drawing has gained significance in cultivating painting skills and human sentiments. In practice, novices often struggle with this art form without proper guidance from professionals, since they lack understanding of the proportions and structures of facial features. To solve this limitation, we have developed a Portrait Drawing Learning Assistant System (PDLAS) to assist novices in learning portrait drawing. The PDLAS provides auxiliary lines as references for facial features that are extracted by applying OpenPose and OpenCV libraries to a face photo image of the target. A learner can draw a portrait on an iPad using drawing software where the auxiliary lines appear on a different layer to the portrait. However, in the current implementation, the PDLAS does not offer a function to assess the exactness of the drawing result for feedback to the learner. In this paper, we present a drawing exactness assessment method using a Localized Normalized Cross-Correlation (NCC) algorithm in the PDLAS. NCC gives a similarity score between the original face photo and drawing result images by calculating the correlation of the brightness distributions. For precise feedback, the method calculates the NCC for each face component by extracting the bounding box. In addition, in this paper, we improve the auxiliary lines for the nose. For evaluations, we asked students at Okayama University, Japan, to draw portraits using the PDLAS, and applied the proposed method to their drawing results, where the application results validated the effectiveness by suggesting improvements in drawing components. The system usability was also confirmed through a questionnaire with a SUS score. The main finding of this research is that the implementation of the NCC algorithm within the PDLAS significantly enhances the accuracy of novice portrait drawings by providing detailed feedback on specific facial features, proving the system's efficacy in art education and training. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2073-8994 16 8 2024 An Enhanced Active Access-Point Configuration Algorithm Using the Throughput Request Satisfaction Method for an Energy-Efficient Wireless Local-Area Network 1005 EN Bin Wu Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Dezheng Kong Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Xuan Wang Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Taishiro Seto Graduate School of Environmental, Life, Natural Science and Technology, Okayama University Yu-Cheng Fan Department of Electronic Engineering, National Taipei University of Technology Wireless Local-Area Networks (WLANs), as a popular internet access solution, are widely used in numerous places, including enterprises, campuses, and public venues. As the number of devices increases, large-scale deployments will cause the problem of dense wireless networks, including a lot of energy consumption. Thus, the optimization of energy-efficient wireless AP devices has become a focal point of attention. To reduce energy consumption, we have proposed the active access-point (AP) configuration algorithm for WLANs using APs with a dual interface. This uses the greedy algorithm combined with the local search optimization method to find the minimum number of activated APs while satisfying the minimum throughput constraint. However, the previous algorithm basically satisfies only the average throughput among the multiple hosts associated with one AP, wherein some hosts may not reach the required one. In this paper, to overcome this limitation, we propose an enhanced active AP configuration algorithm by incorporating the throughput request satisfaction method that controls the actual throughput at the target value (target throughput) for every host by applying traffic shaping. The target throughput is calculated from the single and concurrent communicating throughput of each host based on channel occupancy time. The minimum throughput constraint will be iteratively adjusted to obtain the required target throughput and achieve the fair throughput allocation. For evaluations, we conducted simulations using the WIMNET simulator and experiments using the testbed system with a Raspberry Pi 4B for APs in four topology cases with five APs and ten hosts. The results show that the proposed method always achieved the required minimum throughput in simulations as well as in experiments, while minimizing the number of active APs. Thus, the validity and effectiveness of our proposal were confirmed. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 8 2024 An Image-Based User Interface Testing Method for Flutter Programming Learning Assistant System 464 EN Soe Thandar Aung Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Lynn Htet Aung Department of Information and Communication Systems, Okayama University Safira Adine Kinari Department of Information and Communication Systems, Okayama University Khaing Hsu Wai Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University Flutter has become popular for providing a uniform development environment for user interfaces (UIs) on smart phones, web browsers, and desktop applications. We have developed the Flutter programming learning assistant system (FPLAS) to assist its novice students' self-study. We implemented the Docker-based Flutter environment with Visual Studio Code and three introductory exercise projects. However, the correctness of students' answers is manually checked, although automatic checking is necessary to reduce teachers' workload and provide quick responses to students. This paper presents an image-based user interface (UI) testing method to automate UI testing by the answer code using the Flask framework. This method produces the UI image by running the answer code and compares it with the image made by the model code for the assignment using ORB and SIFT algorithms in the OpenCV library. One notable aspect is the necessity to capture multiple UI screenshots through page transitions by user input actions for the accurate detection of changes in UI elements. For evaluations, we assigned five Flutter exercise projects to fourth-year bachelor and first-year master engineering students at Okayama University, Japan, and applied the proposed method to their answers. The results confirm the effectiveness of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2079-9292 13 15 2024 Performance Investigations of VSLAM and Google Street View Integration in Outdoor Location-Based Augmented Reality under Various Lighting Conditions 2930 EN Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Prismahardi Aji Riyantoko Graduate School of Natural Science and Technology, Okayama University Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Mustika Mentari Graduate School of Natural Science and Technology, Okayama University The growing demand for Location-based Augmented Reality (LAR) experiences has driven the integration of Visual Simultaneous Localization And Mapping (VSLAM) with Google Street View (GSV) to enhance the accuracy. However, the impact of the ambient light intensity on the accuracy and reliability is underexplored, posing significant challenges in outdoor LAR implementations. This paper investigates the impact of light conditions on the accuracy and reliability of the VSLAM/GSV integration approach in outdoor LAR implementations. This study fills a gap in the current literature and offers valuable insights into vision-based approach implementation under different light conditions. Extensive experiments were conducted at five Point of Interest (POI) locations under various light conditions with a total of 100 datasets. Descriptive statistic methods were employed to analyze the data and assess the performance variation. Additionally, the Analysis of Variance (ANOVA) analysis was utilized to assess the impact of different light conditions on the accuracy metric and horizontal tracking time, determining whether there are significant differences in performance across varying levels of light intensity. The experimental results revealed that a significant correlation (p < 0.05) exists between the ambient light intensity and the accuracy of the VSLAM/GSV integration approach. Through the confidence interval estimation, the minimum illuminance 434 lx is needed to provide a feasible and consistent accuracy. Variations in visual references, such as wet surfaces in the rainy season, also impact the horizontal tracking time and accuracy. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2079-9292 13 14 2024 A Reference Paper Collection System Using Web Scraping 2700 EN Inzali Naing Department of Information and Communication Systems, Okayama University Soe Thandar Aung Department of Information and Communication Systems, Okayama University Khaing Hsu Wai Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Collecting reference papers from the Internet is one of the most important activities for progressing research and writing papers about their results. Unfortunately, the current process using Google Scholar may not be efficient, since a lot of paper files cannot be accessed directly by the user. Even if they are accessible, their effectiveness needs to be checked manually. In this paper, we propose a reference paper collection system using web scraping to automate paper collections from websites. This system can collect or monitor data from the Internet, which is considered as the environment, using Selenium, a popular web scraping software, as the sensor; this examines the similarity against the search target by comparing the keywords using the Bert model. The Bert model is a deep learning model for natural language processing (NLP) that can understand context by analyzing the relationships between words in a sentence bidirectionally. The Python Flask is adopted at the web application server, where Angular is used for data presentations. For the evaluation, we measured the performance, investigated the accuracy, and asked members of our laboratory to use the proposed method and provide their feedback. Their results confirm the method’s effectiveness. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 4 2024 A Study of Learning Environment for Initiating Flutter App Development Using Docker 191 EN Soe Thandar Aung Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Lynn Htet Aung Department of Information and Communication Systems, Okayama University Safira Adine Kinari Department of Information and Communication Systems, Okayama University Mustika Mentari Department of Information and Communication Systems, Okayama University Khaing Hsu Wai Department of Information and Communication Systems, Okayama University 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1424-8220 24 7 2024 An Application of Throughput Request Satisfaction Method for Maximizing Concurrent Throughput in WLAN for IoT Application System 2173 EN Bin Wu Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Sujan Chandra Roy Graduate School of Natural Science and Technology, Okayama University Md. Mahbubur Rahman Graduate School of Natural Science and Technology, Okayama University Dezheng Kong Graduate School of Natural Science and Technology, Okayama University Shihao Fang Graduate School of Natural Science and Technology, Okayama University 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 15 3 2024 A Survey of AI Techniques in IoT Applications with Use Case Investigations in the Smart Environmental Monitoring and Analytics in Real-Time IoT Platform 153 EN Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Evianita Dewi Fajrianti Graduate School of Natural Science and Technology, Okayama University Shihao Fang Graduate School of Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1424-8220 24 4 2024 An Enhancement of Outdoor Location-Based Augmented Reality Anchor Precision through VSLAM and Google Street View 1161 EN Komang Candra Brata Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Evianita Dewi Fajrianti Graduate School of Natural Science and Technology, Okayama University 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2624-6120 4 2 2023 A Study of the Active Access-Point Configuration Algorithm under Channel Bonding to Dual IEEE 802.11n and 11ac Interfaces in an Elastic WLAN System for IoT Applications 274 296 EN Sujan Chandra Roy Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Md. Mahbubur Rahman Department Electrical and Electronic Engineering, Jatiya Kabi Kazi Nazrul Islam University Bin Wu Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Currently, Internet of Things (IoT) has become common in various applications, including smart factories, smart cities, and smart homes. In them, wireless local-area networks (WLANs) are widely used due to their high-speed data transfer, flexible coverage ranges, and low costs. To enhance the performance, the WLAN configuration should be optimized in dense WLAN environments where multiple access points (APs) and hosts exist. Previously, we have studied the active AP configuration algorithm for dual interfaces using IEEE802.11n and 11ac protocols at each AP under non-channel bonding (non-CB). In this paper, we study the algorithm considering the channel bonding (CB) to enhance its capacity by bonding two channels together. To improve the throughput estimation accuracy of the algorithm, the reduction factor is introduced at contending hosts for the same AP. For evaluations, we conducted extensive experiments using the WIMENT simulator and the testbed system using Raspberry Pi 4B APs. The results show that the estimated throughput is well matched with the measured one, and the proposal achieves the higher throughput with a smaller number of active APs than the previous configurations. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1424-8220 23 14 2023 An Interface Setup Optimization Method Using a Throughput Estimation Model for Concurrently Communicating Access Points in a Wireless Local Area Network 6367 EN Fatema Akhter Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Ei Ei Htet Graduate School of Natural Science and Technology, Okayama University Bin Wu Graduate School of Natural Science and Technology, Okayama University Dezheng Kong Graduate School of Natural Science and Technology, Okayama University Shihao Fang Graduate School of Natural Science and Technology, Okayama University The IEEE 802.11 wireless local-area network (WLAN) has been deployed around the globe as a major Internet access medium due to its low cost and high flexibility and capacity. Unfortunately, dense wireless networks can suffer from poor performance due to high levels of radio interference resulting from adjoining access points (APs). To address this problem, we studied the AP transmission power optimization method, which selects the maximum or minimum power supplied to each AP so that the average signal-to-interference ratio (SIR) among the concurrently communicating APs is maximized.However, this method requires measurements of receiving signal strength (RSS) under all the possible combinations of powers. It may need intolerable loads and time as the number of APs increases. It also only considers the use of channel bonding (CB), although non-CB sometimes achieves higher performance under high levels of interference. In this paper, we present an AP interface setup optimization method using the throughput estimation model for concurrently communicating APs. The proposed method selects CB or non-CB in addition to the maximum or minimum power for each AP. This model approach avoids expensive costs of RSS measurements under a number of combinations. To estimate the RSS at an AP from another AP or a host, the model needs the distance and the obstacles between them, such as walls. Then, by calculating the estimated RSS with the model and calculating the SIR from them, the AP interface setups for a lot of APs in a large-scale wireless network can be optimized on a computer in a very short time. For evaluation, we conducted extensive experiments using Raspberry Pi for APs and Linux PCs for hosts under 12 network topologies in three buildings at Okayama University, Japan, and Jatiya Kabi Kazi Nazrul Islam University, Bangladesh. The results confirm that the proposed method selects the best AP interface setup with the highest total throughput in any topology. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 14 7 2023 INSUS: Indoor Navigation System Using Unity and Smartphone for User Ambulation Assistance 359 EN Evianita Dewi Fajrianti Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Kong Dezheng Graduate School of Natural Science and Technology, Okayama University Fang Shihao Graduate School of Natural Science and Technology, Okayama University Anak Agung Surya Pradhana Indonesian Institute of Business and Technology (INSTIKI) Currently, outdoor navigation systems have widely been used around the world on smartphones. They rely on GPS (Global Positioning System). However, indoor navigation systems are still under development due to the complex structure of indoor environments, including multiple floors, many rooms, steps, and elevators. In this paper, we present the design and implementation of the Indoor Navigation System using Unity and Smartphone (INSUS). INSUS shows the arrow of the moving direction on the camera view based on a smartphone's augmented reality (AR) technology. To trace the user location, it utilizes the Simultaneous Localization and Mapping (SLAM) technique with a gyroscope and a camera in a smartphone to track users' movements inside a building after initializing the current location by the QR code. Unity is introduced to obtain the 3D information of the target indoor environment for Visual SLAM. The data are stored in the IoT application server called SEMAR for visualizations. We implement a prototype system of INSUS inside buildings in two universities. We found that scanning QR codes with the smartphone perpendicular in angle between 60 degrees and 100 degrees achieves the highest QR code detection accuracy. We also found that the phone's tilt angles influence the navigation success rate, with 90 degrees to 100 degrees tilt angles giving better navigation success compared to lower tilt angles. INSUS also proved to be a robust navigation system, evidenced by near identical navigation success rate results in navigation scenarios with or without disturbance. Furthermore, based on the questionnaire responses from the respondents, it was generally found that INSUS received positive feedback and there is support to improve the system. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 14 6 2023 An Edge Device Framework in SEMAR IoT Application Server Platform 312 EN Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Sho Ito Graduate School of Natural Science and Technology, Okayama University Radhiatul Husna Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University Mitsuhiro Okayasu Graduate School of Natural Science and Technology, Okayama University Junya Shimazu Graduate School of Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 14 6 2023 A Web-Based Docker Image Assistant Generation Tool for User-PC Computing System 300 EN Lynn Htet Aung Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Soe Thandar Aung Graduate School of Natural Science and Technology, Okayama University Xudong Zhou Graduate School of Natural Science and Technology, Okayama University Xu Xiang Graduate School of Natural Science and Technology, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Currently, we are developing the user-PC computing (UPC) system based on the master-worker model as a scalable, low-cost, and high-performance computing platform. To run various application programs on personal computers (PCs) with different environments for workers, it adopts Docker technology to bundle every necessary software as one image file. Unfortunately, the Docker file/image are manually generated through multiple steps by a user, which can be the bottleneck. In this paper, we present a web-based Docker image assistant generation (DIAG) tool in the UPC system to assist or reduce these process steps. It adopts Angular JavaScript for offering user interfaces, PHP Laravel for handling logic using RestAPI, MySQL database for storing data, and Shell scripting for speedily running the whole program. In addition, the worker-side code modification function is implemented so that a user can modify the source code of the running job and update the Docker image at a worker to speed up them. For evaluations, we collected 30 Docker files and 10 OpenFOAM jobs through reverse processing from Docker images in Github and generated the Docker images using the tool. Moreover, we modified source codes for network simulations and generated the Docker images in a worker five times. The results confirmed the validity of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1999-4893 16 1 2023 Three Diverse Applications of General-Purpose Parameter Optimization Algorithm 45 EN Yuanzhi Huo Department of Information and Communication Systems, Okayama University Pradini Puspitaningayu Department of Information and Communication Systems, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Okayama University Kazushi Hamazaki Department of Information and Communication Systems, Okayama University Minoru Kuribayashi Department of Information and Communication Systems, Okayama University Yihan Zhao Department of Mechanical Engineering, Shonan Institute of Technology Kazuyuki Kojima Department of Mechanical Engineering, Shonan Institute of Technology Parameters often take key roles in determining the accuracy of algorithms, logics, and models for practical applications. Previously, we have proposed a general-purpose parameter optimization algorithm, and studied its applications in various practical problems. This algorithm optimizes the parameter values by repeating small changes of them based on a local search method with hill-climbing capabilities. In this paper, we present three diverse applications of this algorithm to show the versatility and effectiveness. The first application is the fingerprint-based indoor localization system using IEEE802.15.4 devices called FILS15.4 that can detect the location of a user in an indoor environment. It is shown that the number of fingerprints for each detection point, the fingerprint values, and the detection interval are optimized together, and the average detection accuracy exceeds 99%. The second application is the human face contour approximation model that is described by a combination of half circles, line segments, and a quadratic curve. It is shown that the simple functions can well approximate the face contour of various persons by optimizing the center coordinates, radii, and coefficients. The third application is the computational fluid dynamic (CFD) simulation to estimate temperature changes in a room. It is shown that the thermal conductivity is optimized to make the average temperature difference between the estimated and measured 0.22 &#8451;. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1999-4893 15 12 2022 A Proposal of Printed Table Digitization Algorithm with Image Processing 471 EN Chenrui Shi Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University Yuanzhi Huo Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University Mustika Mentari Department of Information Technology, State Polytechnic of Malang Kohei Suga Astrolab Takashi Toshida Astrolab Nowadays, digital transformation (DX) is the key concept to change and improve the operations in governments, companies, and schools. Therefore, any data should be digitized for processing by computers. Unfortunately, a lot of data and information are printed and handled on paper, although they may originally come from digital sources. Data on paper can be digitized using an optical character recognition (OCR) software. However, if the paper contains a table, it becomes difficult because of the separated characters by rows and columns there. It is necessary to solve the research question of "how to convert a printed table on paper into an Excel table while keeping the relationships between the cells?" In this paper, we propose a printed table digitization algorithm using image processing techniques and OCR software for it. First, the target paper is scanned into an image file. Second, each table is divided into a collection of cells where the topology information is obtained. Third, the characters in each cell are digitized by OCR software. Finally, the digitalized data are arranged in an Excel file using the topology information. We implement the algorithm on Python using OpenCV for the image processing library and Tesseract for the OCR software. For evaluations, we applied the proposal to 19 scanned and 17 screenshotted table images. The results show that for any image, the Excel file is generated with the correct structure, and some characters are misrecognized by OCR software. The improvement will be in future works. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1424-8220 22 22 2022 A Throughput Request Satisfaction Method for Concurrently Communicating Multiple Hosts in Wireless Local Area Network 8823 EN Md Mahbubur Rahman Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Kwenga Ismael Munene Graduate School of Natural Science and Technology, Okayama University Sujan Chandra Roy Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University Melki Mario Gulo Department of Informatics and Computer Engineering, Politeknik Elektronika Negeri Surabaya Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University 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. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1999-4893 15 10 2022 A Static Assignment Algorithm of Uniform Jobs to Workers in a User-PC Computing System Using Simultaneous Linear Equations 369 EN Xudong Zhou Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Hein Htet Graduate School of Natural Science and Technology, Okayama University Ariel Kamoyedji Graduate School of Natural Science and Technology, Okayama University Irin Tri Anggraini Graduate School of Natural Science and Technology, Okayama University Yuanzhi Huo Graduate School of Natural Science and Technology, Okayama University Yan Watequlis Syaifudin Information Technology Department, State Polytechnic of Malang 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. No potential conflict of interest relevant to this article was reported.

Elsevier BV Acta Medica Okayama 2542-6605 20 2022 A throughput drop estimation model and its application to joint optimization of transmission power, frequency channel, and channel bonding in IEEE 802.11n WLAN for large-scale IoT environments 100583 EN Kwenga Ismael Munene Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Md. Mahbubur Rahman Graduate School of Natural Science and Technology, Okayama University Hendy Briantoro Graduate School of Natural Science and Technology, Okayama University Sujan Chandra Roy Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University The concept of Internet of Things (IoT) has been widely studied in smart home networks, smart city networks, smart grid systems, autonomous driving systems, and smart healthcare systems. In IoT, the IEEE 802.11n wireless local-area network (WLAN) is used as a common communication technology due to its exibility and low cost. Then, the high performance WLAN is required to enhance quality of service (QoS) of large-scale IoT applications connecting a number of devices or sensors allocated in wide areas. WLAN can use the limited number of partially overlapping channels (POCs) at 2.4 GHz band. The WLAN performance can be degraded by interfered signals from other WLANs. Then, to optimize the POC assignment by reducing interferences, we have proposed the throughput drop estimation model for concurrently communicating multiple links under interferences. Unfortunately, the 40 MHz channel bonding (CB) and the 20 MHz non-CB are considered separately, while the transmission power is always fixed to the maximum. In this paper, we study the throughput drop estimation model under coexistence of CB and non-CB while the transmission power is changed. Then, we present its application to the joint optimization of assigning the transmission power, the frequency channel, and the channel bonding to enhance the throughput performance of IEEE 802.11n WLAN. For evaluations, we compare estimated throughputs by the model with measured ones in various network topologies to verify the model accuracy. Then, we apply the model to the joint assignment optimization in them, and confirm the effectiveness through simulations and experiments using the testbed system. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 1424-8220 22 17 2022 Design and Implementation of SEMAR IoT Server Platform with Applications 6436 EN Yohanes Yohanie Fridelin Panduman Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Pradini Puspitaningayu Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University Sritrusta Sukaridhoto Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Nowadays, rapid developments of Internet of Things (IoT) technologies have increased possibilities of realizing smart cities where collaborations and integrations of various IoT application systems are essential. However, IoT application systems have often been designed and deployed independently without considering the standards of devices, logics, and data communications. In this paper, we present the design and implementation of the IoT server platform called Smart Environmental Monitoring and Analytical in Real-Time (SEMAR) for integrating IoT application systems using standards. SEMAR offers Big Data environments with built-in functions for data aggregations, synchronizations, and classifications with machine learning. Moreover, plug-in functions can be easily implemented. Data from devices for different sensors can be accepted directly and through network connections, which will be used in real-time for user interfaces, text files, and access to other systems through Representational State Transfer Application Programming Interface (REST API) services. For evaluations of SEMAR, we implemented the platform and integrated five IoT application systems, namely, the air-conditioning guidance system, the fingerprint-based indoor localization system, the water quality monitoring system, the environment monitoring system, and the air quality monitoring system. When compared with existing research on IoT platforms, the proposed SEMAR IoT application server platform offers higher flexibility and interoperability with the functions for IoT device managements, data communications, decision making, synchronizations, and filters that can be easily integrated with external programs or IoT applications without changing the codes. The results confirm the effectiveness and efficiency of the proposal. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2078-2489 13 5 2022 A Proposal of the Fingerprint Optimization Method for the Fingerprint-Based Indoor Localization System with IEEE 802.15.4 Devices 211 EN Yuanzhi Huo Department of Electrical and Communication Engineering, Okayama University Pradini Puspitaningayu Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Kazushi Hamazaki Department of Electrical and Communication Engineering, Okayama University Minoru Kuribayashi Department of Electrical and Communication Engineering, Okayama University Kazuyuki Kojima Mechanical Engineering, Shonan Institute of Technology Nowadays, human indoor localization services inside buildings or on underground streets are in strong demand for various location-based services. Since conventional GPS cannot be used, indoor localization systems using wireless technologies have been extensively studied. Previously, we studied a fingerprint-based indoor localization system using IEEE802.15.4 devices, called FILS15.4, to allow use of inexpensive, tiny, and long-life transmitters. However, due to the narrow channel band and the low transmission power, the link quality indicator (LOI) used for fingerprints easily fluctuates by human movements and other uncontrollable factors. To improve the localization accuracy, FILS15.4 restricts the detection granularity to one room in the field, and adopts multiple fingerprints for one room, considering fluctuated signals, where their values must be properly adjusted. In this paper, we present a fingerprint optimization method for finding the proper fingerprint parameters in FILS15.4 by extending the existing one. As the training phase using the measurement LQI, it iteratively changes fingerprint values to maximize the newly defined score function for the room detecting accuracy. Moreover, it automatically increases the number of fingerprints for a room if the accuracy is not sufficient. For evaluations, we applied the proposed method to the measured LQI data using the FILS15.4 testbed system in the no. 2 Engineering Building at Okayama University. The validation results show that it improves the average detection accuracy (at higher than 97%) by automatically increasing the number of fingerprints and optimizing the values. No potential conflict of interest relevant to this article was reported.

Emerald Acta Medica Okayama 1744-0084 17 2 2021 A proposal of recommendation function for element fill-in-Blank problems in java programming learning assistant system 140 152 EN Su Sandy Wint Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Yan Watequlis Syaifudin Department of Electrical and Communication Engineering, Okayama University Shune Lae Aung Department of Computer Studies, University of Yangon Wen-Chun Kao Department of Electrical Engineering, National Taiwan Normal University Purpose<br> 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.<br> <br> Design/methodology/approach<br> 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.<br> <br> Findings<br> 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.<br> <br> Originality/value<br> 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. No potential conflict of interest relevant to this article was reported.

Emerald Acta Medica Okayama 1744-0084 16 2 2019 A proposal of calligraphy learning assistant system with letter portion practice function using projection mapping 137 149 EN Samsul Huda Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Minoru Kuribayashi Department of Electrical and Communication Engineering, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University Purpose</br> For several decades, calligraphy has been popular among people in Japan, China, and even in the world. Traditionally, a teacher teaches how to write letters on a paper with a brush, and a student will imitate them by referring to the model letters. However, if a teacher is not available, this method will not be applicable either. This study aims to propose a calligraphy learning assistant system (CLAS) using projection mapping, which allows a student to learn calligraphy by him/herself.</br> Design/methodology/approach</br> By following the letter writing video of a teacher that is directly projected on the paper, a student is able to learn the stroke order and writing speed in addition to the letter shape. Moreover, the letter portion practice function is incorporated in CLAS to allow a learner to repeat practicing hard portions of each letter.</br> Findings</br> For evaluations, the authors implemented CLAS using Raspberry Pi and open-source software and asked students to use it. The results confirmed that CLAS is effective in improving calligraphy skills of novice students.</br> Originality/value</br> With CLAS, a student can practice calligraphy using a conventional brush, ink and paper at a desk while looking at the model letter writing of a teacher projected on the paper using projection mapping. No potential conflict of interest relevant to this article was reported.

Emerald Acta Medica Okayama 17440084 16 1 2019 A proposal of Android Programming Learning Assistant System with implementation of basic application learning 115 135 EN Yan Watequlis Syaifudin Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Minoru Kuribayashi Department of Electrical and Communication Engineering, Okayama University Wen-Chung Kao National Taiwan Normal University Purpose</br> With rapid increase of Android devices and application systems, there is a strong demand for Android application programmers. A lot of schools are offering Android programming courses to meet this demand. However, Android programming can be different from the conventional one because it needs interactive functions through interfaces with users, which makes the study more difficult. This paper aims to propose an Android Programming Learning Assistance System, namely, APLAS, to assist the Java-based Android programming study and education.</br> Design/methodology/approach</br> By adopting the test-driven development method, APLAS is designed to achieve independent learning without the presence of teachers. Using JUnit and Robolectric, the answers from the students are automatically marked in APLAS. To cover extensive materials in Android programming, APLAS offers four stages where each stage involves several topics.</br> Findings</br> To evaluate the effectiveness of APLAS, we implemented the Unit Converter assignment that covers the first two topics, namely, Basic user interface in the first stage and basic activity in the second stage. Through solving the assignment, it is expected to learn basic application development. Forty novice students of an IT department in Indonesia were asked to solve both topics separately.</br> Originality/value</br> The results show that APLAS is useful and helpful for the self-study of Android programming, as they could complete codes with good execution performances. No potential conflict of interest relevant to this article was reported.

Institute of Electrical and Electronics Engineers Acta Medica Okayama 15566013 15 2019 Near-Optimal Detection for Binary Tardos Code by Estimating Collusion Strategy 2069 2080 EN Tatsuya Yasui Graduate School of Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Isao Echizen National Institute of Informatics A previously proposed optimal detector for bias-based fingerprinting codes such as Tardos and Nuida requires two kinds of important information: the number of colluders and the collusion strategy used to generate the pirated codeword. An estimator has now been derived for these two parameters. The bias in the pirated codeword is measured by observing the number of zeros and ones and compared with possible bias patterns calculated using information about the collusion strategy and number of colluders. Computer simulation demonstrated that the collusion strategy and number of colluders can be estimated with high probability and that the traceability of a detector using the proposed estimator is extremely close to being optimal. No potential conflict of interest relevant to this article was reported.

Springer Acta Medica Okayama 2194-5357 2018 A Proposal of Code Completion Problem for Java Programming Learning Assistant System 855 864 EN Htoo Htoo Sandi Kyaw Department of Information Science and TechnologyUniversity of Technology Yatanarpon Cyber City Shwe Thinzar Aung Department of Information Science and TechnologyUniversity of Technology Yatanarpon Cyber City Hnin Aye Thant Department of Electrical and Communication Engineering Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering Okayama University 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. No potential conflict of interest relevant to this article was reported.

Inderscience Enterprises Ltd. Acta Medica Okayama 20444893 9 1 2019 Enhancements of minimax access-point setup optimisation approach for IEEE 802.11 WLAN 47 59 EN Kyaw Soe Lwin Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University Sumon Kumar Debnath Graduate School of Natural Science and Technology, Okayama University Ismael Munene Kwenga Graduate School of Natural Science and Technology, Okayama University Rahardhita Widyatra Sudibyo Graduate School of Natural Science and Technology, Okayama University Minoru Kuribayashi Graduate School of Natural Science and Technology, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University As a flexible and cost-efficient internet access network, the IEEE 802.11 wireless local-area network (WLAN) has been broadly deployed around the world. Previously, to improve the IEEE 802.11n WLAN performance, we proposed the four-step minimax access-point (AP) setup optimisation approach: 1) link throughputs between the AP and hosts in the network field are measured manually; 2) the throughput estimation model is tuned using the measurement results; 3) the bottleneck host suffering the least throughput is estimated using this model; 4) the AP setup is optimised to maximise the throughput of the bottleneck host. Unfortunately, this approach has drawbacks: 1) a lot of manual throughput measurements are necessary to tune the model; 2) the shift of the AP location is not considered; 3) IEEE 802.11ac devices at 5 GHz are not evaluated, although they can offer faster transmissions. In this paper, we present the three enhancements: 1) the number of measurement points is reduced while keeping the model accuracy; 2) the coordinate of the AP setup is newly adopted as the optimisation parameter; 3) the AP device with IEEE 802.11ac at 5 GHz is considered with slight modifications. The effectiveness is confirmed by extensive experiments in three network fields. No potential conflict of interest relevant to this article was reported.

INDERSCIENCE ENTERPRISES Acta Medica Okayama 2044-4893 8 1 2018 A holding access-point assignment algorithm for IEEE802.11 wireless local-area networks 50 58 EN Shigeto Tajima Nobuo Funabiki Teruo Higashino Nowadays, various types of access-points (APs) and hosts such as dedicated APs, laptop personal computers (PCs), and mobile terminals have been used in IEEE802.11 wireless local-area networks (WLANs). As a result, the optimal assignment of holding APs with different types into the network field, depending on the host type distribution, has become another important task to design high-performance WLANs. In this paper, we first define this holding access-point assignment problem as a combinatorial optimisation problem and propose its two-phase heuristic algorithm. Then, since plural partially overlapping channels are available in IEEE802.11 WLANs, we present the channel assignment extension to the APs such that the communication time of the APs is minimised, and the model to estimate the communication time increase by interferences. The effectiveness of our proposal is verified through simulations in six instances using the WIMNET simulator. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 24156698 3 1 2018 A Test Code Generation Method for Coding Standard Input/Output with Exception Handling in Java Programming Learning Assistant System 30 37 EN Ei Ei Mon Okayama University, Department of Electrical and Communication Engineering Nobuo Funabiki Okayama University, Department of Electrical and Communication Engineering Ryota Kusaka Okayama University, Department of Electrical and Communication Engineering Khin Khin Zaw Okayama University, Department of Electrical and Communication Engineering Wen-Chung Kao National Taiwan Normal University, Department of Electrical Engineering To advance Java programming educations, we have developed the Java Programming Learning Assistant System (JPLAS) that provides the code writing problem. This problem asks a student to write a source code to satisfy the specification of a given assignment, where the correctness is verified by running test code on JUnit. For a novice student, a code of implementing the standard input/output with the exception handling should be mastered at the early stage as the first step programming for human interfaces. However, for a teacher, it is not easy to write the test code for it. In this paper, we propose a test code generation method to generate the test code using the reference source code for the assignment. In the evaluation of this proposal, all the students completed the codes using the generated test codes for exception handling, although the use of exception handling functions was sometimes insufficient or incorrect. No potential conflict of interest relevant to this article was reported.

INDERSCIENCE ENTERPRISES Acta Medica Okayama 2044-4893 7 3 2017 A design-aware test code approach for code writing problem in Java programming learning assistant system 145 154 EN Khin Khin Zaw Graduate School of Natural Science and Technology, Okayama University Nobuo Funabiki Graduate School of Natural Science and Technology, Okayama University To advance Java programming educations, we have developed the web-based Java programming learning assistant system (JPLAS) that provides the code writing problem. This problem asks a student to write a source code for a given assignment, where the correctness is verified by running the test code on JUnit. In this paper, we propose a design-aware test code approach for the code writing problem. The design-aware test code tests any important method in the model source code that has the advisable design for the assignment. Thus, by writing a code that can pass it, a student is expected to implement the code with the proper classes/methods in the model code. In evaluations of the proposal, all the students could complete highly qualitative codes for five graph algorithms using the design-aware test codes, where the code quality metrics were measured by metrics plugin for Eclipse. No potential conflict of interest relevant to this article was reported.

Graphy Publications Acta Medica Okayama 2456-4451 2 1 2017 A software architecture for Java programming learning assistant system 116 EN Nobuya Ishihara Department of Electrical and Communication Engineering, Okayama University Nobuo Funabiki Department of Electrical and Communication Engineering, Okayama University Minoru Kuribayashi Department of Electrical and Communication Engineering, Okayama University Wen-Chung Kao Department of Electrical Engineering, National Taiwan Normal University For advancements of Java programming educations, we have developed a Web-based Java Programming Learning System (JPLAS). JPLAS provides four problems with different levels, namely, element fill-inblank problem, value trace problem, statement fill-in-blank problem, and code writing problem, to cover students at different learning stages. Unfortunately, since JPLAS has been implemented by a number of students who studied in our group at different years, the code has become complex and redundant, which makes further extensions of JPLAS extremely hard. In this paper, we propose a software architecture for JPLAS to avoid redundancy. Based on the MVC model, our proposal uses Java for the model (M), HTML/CSS/JavaScript for the view (V), and JSP for the controller (C). Besides, adopting a design pattern, the marking functions of the four problems are implemented uniformly. For evaluations, after JPLAS is implemented with this architecture, the number of code files is compared with that of the previous implementation, and the number of additional files is examined for two new functions. No potential conflict of interest relevant to this article was reported.

IJNC Editorial Committee Acta Medica Okayama 2185-2839 7 2 2017 A Channel Assignment Extension of Active Access-Point Configuration Algorithm for Elastic WLAN System and Its Implementation Using Raspberry Pi 248 270 EN Md. Selim Al Mamun Okayama University Nobuo Funabiki Okayama University Kyaw Soe Lwin Okayama University Md. Ezharul Islam Okayama University Wen-Chung Kao National Taiwan Normal University Recently, Wireless Local-Area Network (WLAN) has become prevailing as it provides flexible Internet access to users with low cost through installation of several types of access points (APs) in the network. Previously, we proposed the active AP configuration algorithm for the elastic WLAN system using heterogeneous APs, which dynamically optimizes the configuration by activating or deactivating APs based on traffic demands. However, this algorithm assumes that any active AP may use a different channel from the other ones to avoid interferences, although the number of non-interfered channels in IEEE 802.11 protocols is limited. In this paper, we propose the extension of the AP configuration algorithm to consider the channel assignment to the active APs under this limitation. Besides, AP associations of the hosts are modified to improve the network performance by averaging loads among channels. The effectiveness of our proposal is evaluated using the WIMNET simulator in two topologies. Finally, the elastic WLAN system including this proposal is implemented using Raspberry Pi for the AP. The feasibility and performance of the implementation are verified through experiments using the testbed. No potential conflict of interest relevant to this article was reported.

IJNC Editorial Committee Acta Medica Okayama 21852847 7 2 2017 A Minimax Approach for Access Point Setup Optimization in IEEE 802.11n Wireless Networks 187 207 EN Kyaw Soe Lwin Okayama University Nobuo Funabiki Okayama University Chihiro Taniguchi Okayama University Khin Khin Zaw Okayama University Md. Selim Al Mamun Okayama University Minoru Kuribayashi Okayama University Wen-Chung Kao National Taiwan Normal University Recently, an IEEE 802.11n access point (AP) prevailed over the wireless local area network (WLAN) due to the high-speed data transmission using the multiple input multiple output (MIMO) technology. Unfortunately, the signal propagation from the 802.11n AP is not uniform in the circumferential and height directions because of the multiple antennas for MIMO. As a result, the data transmission speed between the AP and a host could be significantly affected by their relative setup conditions. In this paper, we propose a minimax approach for optimizing the 802.11n AP setup condition in terms of the angles and the height in an indoor environment using throughput measurements. First, we detect a bottleneck host that receives the weakest signal from the AP in the field using the throughput estimation model. To explore optimal values of parameters for this model, we adopt the versatile parameter optimization tool. Then, we optimize the AP setup by changing the angles and the height while measuring throughput. For evaluations, we verify the accuracy of the model using measurement results and confirm the throughput improvements for hosts in the field by our approach. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2001 A global routing technique for wave-steered design methodology 430 436 EN Nobuo Funabiki Amit Singh Arindam Mukherjee Malgorzata Marek Sadowska <p>Wave-Steering is a new circuit design methodology to realize high throughput circuits by embedding layout friendly structures in silicon. Latches guarantee correct signal arrival times at the input of synthesized modules and maintain the high throughput of operation. This paper presents a global routing technique for networks of wave-steered blocks. Latches can be distributed along interconnects. Their number depends on net topologies and signal ordering at the inputs of wave steered blocks. here, we route nets using Steiner tree heuristics and determine signal ordering and latch positions on interconnect. The problem of total latch number minimization is solved using SAT formulation. Experimental results on benchmark circuits show the efficiency of our technique. We achieve on average a 40% latch reduction at minimum latency over un-optimized circuits operating at 250 MHz in 0.25 &#956;m CMOS technology</p> No potential conflict of interest relevant to this article was reported.

IEEE Computer Society Acta Medica Okayama 1550-445X 1 2005 Optical-drop wavelength assignment problem for wavelength reuse in WDM ring metropolitan area networks 999 1004 EN Nobuo Funabiki Megumi Isogai Toru Nakanishi Teruo Higashino This paper presents a formulation of the optical-drop wavelength assignment problem (ODWAP) and its heuristic algorithm for WDM ring networks. 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 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 tunable transmitter so that a lightpath can be established between any pair of nodes without wavelength conversions. In this paper, we formulate ODWAP for efficient wavelength reuse under heterogeneous traffic in this network. Then, we propose a simple heuristic algorithm for 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. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 1 2005 Compact tree plus algorithms for application-level multicast communications in multihome networks EN Nobuo Funabiki Megumi Isogai Toru Nakanishi Teruo Higashino <p>Application-level multicast (ALM) communications replicate packets on host level to deliver them from a single source to multiple clients, so that it can efficiently realize a variety of network applications using moving pictures such as video conferences, distance learning, and video-on-demands. In this paper, we propose the CT+ (compact tree plus) algorithm for finding a better ALM routing tree in terms of delay minimization between hosts. CT+ consists of a tree construction stage from the existing CT algorithm, and a newly added iterative tree improvement stage. Then, we define the extended ALM routing problem and its heuristic algorithm ExCT+, to optimize the effectiveness of the multihome network in ALM communications by selecting multihomed hosts and connections in the ALM routing tree simultaneously. For their evaluations, we construct a network simulation model named MINET (multiple-ISP network simulator), where the topology is composed of multiple ISP backbone networks with IX connections, and the network traffic is generated by following the M/M/1 queuing process. The simulation results using MINET verify the effectiveness of our algorithms.</p> No potential conflict of interest relevant to this article was reported.

IEEE Computer Society Acta Medica Okayama 2003 A proposal of a minimal-state processing search algorithm for isochronous channel reuse problems in DQDB networks 229 232 EN Nobuo Funabiki Ayako Sugano Teruo Higashino The IEEE 802.6 MAC standard protocol defines the distributed-queue dual bus (DQDB) for metropolitan area networks (MANs). The isochronous channel reuse problem (ICRP) has been studied for the efficient use of DQDB. Given a set of established connections and a set of connection requests, the goal of ICRP is to maximize the number of satisfied requests by finding a proper channel assignment, such that no established connection is not only reassigned a channel, but also any pair of active connections does not interfere each other. We propose a minimal-state processing search algorithm for ICRP (MIPS/sub -/ICRP). The simulation results show that MIPS/sub -/ICRP always provides near-optimum solutions. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2006 A LECCS model parameter optimization algorithm for EMC designs of IC/LSI systems 304 307 EN Nobuo Funabiki Yohei Nomura Jun Kawashima Yuichiro Minamisawa Osami Wada <p>&lt;p&gt;In this paper, we propose a parameter optimization algorithm for EMC macro-modeling of IC/LSI power currents called the LECCS (linear equivalent circuit and current source) model. The unnecessary electro-magnetic wave from a digital electronics device may cause the electromagnetic interference (EMI) to other apparatus. Thus, its reduction has been regarded as one of the highest priority issues in digital electronics device designs. In order to accurately simulate high-frequency currents from power-supply sources that are the primary sources of EMI, the LECCS model has been proposed as a linear macromodel of a power-supply circuit. A LECCS model consists of multiple RLC-series circuits in parallel to represent the equivalent circuit between the voltage source and the ground. Given a set of measured impedances at various frequencies, our proposed algorithm first finds the number of RLC-series circuits corresponding to the number of valleys. Then, it searches optimal values of RLC parameters by a local search method. The effectiveness of our algorithm is verified through applications to a real system, where the accuracy and the required processing time by our algorithm are compared with the conventional method.&lt;/p&gt;</p> No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 2006 A LECCS model parameter optimization algorithm for EMC designs of IC/LSI systems 304 307 EN Nobuo Funabiki Yohei Nomura Jun Kawashima Yuichiro Minamisawa Osami Wada <p>In this paper, we propose a parameter optimization algorithm for EMC macro-modeling of IC/LSI power currents called the LECCS (linear equivalent circuit and current source) model. The unnecessary electro-magnetic wave from a digital electronics device may cause the electromagnetic interference (EMI) to other apparatus. Thus, its reduction has been regarded as one of the highest priority issues in digital electronics device designs. In order to accurately simulate high-frequency currents from power-supply sources that are the primary sources of EMI, the LECCS model has been proposed as a linear macromodel of a power-supply circuit. A LECCS model consists of multiple RLC-series circuits in parallel to represent the equivalent circuit between the voltage source and the ground. Given a set of measured impedances at various frequencies, our proposed algorithm first finds the number of RLC-series circuits corresponding to the number of valleys. Then, it searches optimal values of RLC parameters by a local search method. The effectiveness of our algorithm is verified through applications to a real system, where the accuracy and the required processing time by our algorithm are compared with the conventional method.</p> No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 4 2001 A minimal-state processing search algorithm for satisfiability problems 2769 2774 EN Nobuo Funabiki Tokumi Yokohira Toru Nakanishi Shigeto Tajima Teruo Higashino <p>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</p> No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 40 1 2006 An Eye-Contour Extraction Algorithm from Face Image usingDeformable Template Matching 78 82 EN Nobuo Funabiki Megumi Isogai Teruo Higashino 10.18926/14125 A variety of studies on face components such as eyes, lips, noses, and teeth have been proceeding in medicine, psychology, biometrics authentication, and other areas. In this paper, we present an algorithm of extracting eye contours from a face image using the deformable template matching method. Our template for an eye contour is composed of three quadratic functions for the perimeter and one circle for the pupil. In our algorithm, a digital color face image is rst converted to a binary image of representing eyes, after the region around eyes is identied on the face image by using hues and values of the color image. Then, parameters in the template are optimized by a local search method with a tabu period and a hill-climbing, so as to t the template to the eye contour in the binary image. The accuracy of our algorithm is evaluated through sample face images of students. In addition, the application of our proposal to eye shape indices is investigated in a face image database "HOIP", where recognizable dierence exists in index distributions between males and females. No potential conflict of interest relevant to this article was reported.