start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=4 article-no= start-page=191 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240330 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Study of Learning Environment for Initiating Flutter App Development Using Docker en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=AungSoe Thandar en-aut-sei=Aung en-aut-mei=Soe Thandar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=AungLynn Htet en-aut-sei=Aung en-aut-mei=Lynn Htet kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KinariSafira Adine en-aut-sei=Kinari en-aut-mei=Safira Adine kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MentariMustika en-aut-sei=Mentari en-aut-mei=Mustika kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=WaiKhaing Hsu en-aut-sei=Wai en-aut-mei=Khaing Hsu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=2 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=3 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=4 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=5 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=6 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= en-keyword=Flutter kn-keyword=Flutter en-keyword=Dart kn-keyword=Dart en-keyword=app kn-keyword=app en-keyword=Docker kn-keyword=Docker en-keyword=Visual Studio Code kn-keyword=Visual Studio Code en-keyword=environment kn-keyword=environment en-keyword=code modification kn-keyword=code modification END start-ver=1.4 cd-journal=joma no-vol=24 cd-vols= no-issue=7 article-no= start-page=2173 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240328 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Application of Throughput Request Satisfaction Method for Maximizing Concurrent Throughput in WLAN for IoT Application System en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=WuBin en-aut-sei=Wu en-aut-mei=Bin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=RoySujan Chandra en-aut-sei=Roy en-aut-mei=Sujan Chandra kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=RahmanMd. Mahbubur en-aut-sei=Rahman en-aut-mei=Md. Mahbubur kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KongDezheng en-aut-sei=Kong en-aut-mei=Dezheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=FangShihao en-aut-sei=Fang en-aut-mei=Shihao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Raspberry Pi kn-keyword=Raspberry Pi en-keyword=WLAN kn-keyword=WLAN en-keyword=traffic shaping kn-keyword=traffic shaping en-keyword=access point kn-keyword=access point en-keyword=target throughput kn-keyword=target throughput en-keyword=throughput maximization kn-keyword=throughput maximization en-keyword=high-density IoT networks kn-keyword=high-density IoT networks END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=3 article-no= start-page=153 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240309 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Survey of AI Techniques in IoT Applications with Use Case Investigations in the Smart Environmental Monitoring and Analytics in Real-Time IoT Platform en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=PandumanYohanes Yohanie Fridelin en-aut-sei=Panduman en-aut-mei=Yohanes Yohanie Fridelin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FajriantiEvianita Dewi en-aut-sei=Fajrianti en-aut-mei=Evianita Dewi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FangShihao en-aut-sei=Fang en-aut-mei=Shihao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SukaridhotoSritrusta en-aut-sei=Sukaridhoto en-aut-mei=Sritrusta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya kn-affil= en-keyword=Internet of Things kn-keyword=Internet of Things en-keyword=AI kn-keyword=AI en-keyword=integration kn-keyword=integration en-keyword=survey kn-keyword=survey en-keyword=application server platform kn-keyword=application server platform en-keyword=SEMAR kn-keyword=SEMAR END start-ver=1.4 cd-journal=joma no-vol=24 cd-vols= no-issue=4 article-no= start-page=1161 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2024 dt-pub=20240209 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Enhancement of Outdoor Location-Based Augmented Reality Anchor Precision through VSLAM and Google Street View en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=BrataKomang Candra en-aut-sei=Brata en-aut-mei=Komang Candra kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=PandumanYohanes Yohanie Fridelin en-aut-sei=Panduman en-aut-mei=Yohanes Yohanie Fridelin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FajriantiEvianita Dewi en-aut-sei=Fajrianti en-aut-mei=Evianita Dewi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=location-based kn-keyword=location-based en-keyword=augmented reality kn-keyword=augmented reality en-keyword=SLAM kn-keyword=SLAM en-keyword=cloud-based matching kn-keyword=cloud-based matching en-keyword=Android kn-keyword=Android END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue=2 article-no= start-page=274 end-page=296 dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230403 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=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 en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=RoySujan Chandra en-aut-sei=Roy en-aut-mei=Sujan Chandra kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=RahmanMd. Mahbubur en-aut-sei=Rahman en-aut-mei=Md. Mahbubur kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=WuBin en-aut-sei=Wu en-aut-mei=Bin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department Electrical and Electronic Engineering, Jatiya Kabi Kazi Nazrul Islam University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=Internet of Things kn-keyword=Internet of Things en-keyword=WLAN kn-keyword=WLAN en-keyword=access-points configuration kn-keyword=access-points configuration en-keyword=dual interface kn-keyword=dual interface en-keyword=channel bonding kn-keyword=channel bonding en-keyword=WIMNET kn-keyword=WIMNET en-keyword=Raspberry Pi 4B kn-keyword=Raspberry Pi 4B en-keyword=IEEE802.11n kn-keyword=IEEE802.11n en-keyword=11ac kn-keyword=11ac END start-ver=1.4 cd-journal=joma no-vol=23 cd-vols= no-issue=14 article-no= start-page=6367 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230713 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Interface Setup Optimization Method Using a Throughput Estimation Model for Concurrently Communicating Access Points in a Wireless Local Area Network en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=AkhterFatema en-aut-sei=Akhter en-aut-mei=Fatema kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HtetEi Ei en-aut-sei=Htet en-aut-mei=Ei Ei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=WuBin en-aut-sei=Wu en-aut-mei=Bin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KongDezheng en-aut-sei=Kong en-aut-mei=Dezheng kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=FangShihao en-aut-sei=Fang en-aut-mei=Shihao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=wireless local area network kn-keyword=wireless local area network en-keyword=signal-to-interference ratio kn-keyword=signal-to-interference ratio en-keyword=interface setup optimization kn-keyword=interface setup optimization en-keyword=throughput estimation model kn-keyword=throughput estimation model en-keyword=channel bonding kn-keyword=channel bonding END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=7 article-no= start-page=359 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230624 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=INSUS: Indoor Navigation System Using Unity and Smartphone for User Ambulation Assistance en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=FajriantiEvianita Dewi en-aut-sei=Fajrianti en-aut-mei=Evianita Dewi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SukaridhotoSritrusta en-aut-sei=Sukaridhoto en-aut-mei=Sritrusta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=PandumanYohanes Yohanie Fridelin en-aut-sei=Panduman en-aut-mei=Yohanes Yohanie Fridelin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=DezhengKong en-aut-sei=Dezheng en-aut-mei=Kong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ShihaoFang en-aut-sei=Shihao en-aut-mei=Fang kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=Surya Pradhana Anak Agung en-aut-sei=Surya Pradhana en-aut-mei= Anak Agung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Indonesian Institute of Business and Technology (INSTIKI) kn-affil= en-keyword=indoor navigation system kn-keyword=indoor navigation system en-keyword=INSUS kn-keyword=INSUS en-keyword=unity kn-keyword=unity en-keyword=QR code kn-keyword=QR code en-keyword=smartphone kn-keyword=smartphone en-keyword=SEMAR kn-keyword=SEMAR END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=6 article-no= start-page=312 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230529 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Edge Device Framework in SEMAR IoT Application Server Platform en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=PandumanYohanes Yohanie Fridelin en-aut-sei=Panduman en-aut-mei=Yohanes Yohanie Fridelin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ItoSho en-aut-sei=Ito en-aut-mei=Sho kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HusnaRadhiatul en-aut-sei=Husna en-aut-mei=Radhiatul kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=OkayasuMitsuhiro en-aut-sei=Okayasu en-aut-mei=Mitsuhiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ShimazuJunya en-aut-sei=Shimazu en-aut-mei=Junya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=SukaridhotoSritrusta en-aut-sei=Sukaridhoto en-aut-mei=Sritrusta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=8 en-affil=Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya kn-affil= en-keyword=Internet of Things kn-keyword=Internet of Things en-keyword=edge device kn-keyword=edge device en-keyword=framework kn-keyword=framework en-keyword=application server platform kn-keyword=application server platform en-keyword=SEMAR kn-keyword=SEMAR END start-ver=1.4 cd-journal=joma no-vol=14 cd-vols= no-issue=6 article-no= start-page=300 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230523 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Web-Based Docker Image Assistant Generation Tool for User-PC Computing System en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=AungLynn Htet en-aut-sei=Aung en-aut-mei=Lynn Htet kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=AungSoe Thandar en-aut-sei=Aung en-aut-mei=Soe Thandar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=ZhouXudong en-aut-sei=Zhou en-aut-mei=Xudong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=XiangXu en-aut-sei=Xiang en-aut-mei=Xu kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=Docker kn-keyword=Docker en-keyword=automatic generation kn-keyword=automatic generation en-keyword=Angular kn-keyword=Angular en-keyword=Laravel kn-keyword=Laravel en-keyword=MySQL kn-keyword=MySQL en-keyword=Shell scripting kn-keyword=Shell scripting en-keyword=image update kn-keyword=image update en-keyword=UPC system kn-keyword=UPC system END start-ver=1.4 cd-journal=joma no-vol=16 cd-vols= no-issue=1 article-no= start-page=45 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2023 dt-pub=20230109 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Three Diverse Applications of General-Purpose Parameter Optimization Algorithm en-subtitle= kn-subtitle= en-abstract= kn-abstract=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 ℃. en-copyright= kn-copyright= en-aut-name=HuoYuanzhi en-aut-sei=Huo en-aut-mei=Yuanzhi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=PuspitaningayuPradini en-aut-sei=Puspitaningayu en-aut-mei=Pradini kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HamazakiKazushi en-aut-sei=Hamazaki en-aut-mei=Kazushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ZhaoYihan en-aut-sei=Zhao en-aut-mei=Yihan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KojimaKazuyuki en-aut-sei=Kojima en-aut-mei=Kazuyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=2 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=3 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=4 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=5 en-affil=Department of Information and Communication Systems, Okayama University kn-affil= affil-num=6 en-affil=Department of Mechanical Engineering, Shonan Institute of Technology kn-affil= affil-num=7 en-affil=Department of Mechanical Engineering, Shonan Institute of Technology kn-affil= en-keyword=parameter optimization kn-keyword=parameter optimization en-keyword=application kn-keyword=application en-keyword=indoor localization kn-keyword=indoor localization en-keyword=face contour model kn-keyword=face contour model en-keyword=computational fluid dynamics kn-keyword=computational fluid dynamics END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=12 article-no= start-page=471 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221211 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Proposal of Printed Table Digitization Algorithm with Image Processing en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=ShiChenrui en-aut-sei=Shi en-aut-mei=Chenrui kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HuoYuanzhi en-aut-sei=Huo en-aut-mei=Yuanzhi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MentariMustika en-aut-sei=Mentari en-aut-mei=Mustika kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SugaKohei en-aut-sei=Suga en-aut-mei=Kohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=ToshidaTakashi en-aut-sei=Toshida en-aut-mei=Takashi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Department of Information and Communication Systems, Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Department of Information Technology, State Polytechnic of Malang kn-affil= affil-num=5 en-affil=Astrolab kn-affil= affil-num=6 en-affil=Astrolab kn-affil= en-keyword=digitization kn-keyword=digitization en-keyword=printed table kn-keyword=printed table en-keyword=OCR kn-keyword=OCR en-keyword=Python kn-keyword=Python en-keyword=OpenCV kn-keyword=OpenCV en-keyword=Tesseract kn-keyword=Tesseract END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=22 article-no= start-page=8823 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221115 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Throughput Request Satisfaction Method for Concurrently Communicating Multiple Hosts in Wireless Local Area Network en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=RahmanMd Mahbubur en-aut-sei=Rahman en-aut-mei=Md Mahbubur kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MuneneKwenga Ismael en-aut-sei=Munene en-aut-mei=Kwenga Ismael kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=RoySujan Chandra en-aut-sei=Roy en-aut-mei=Sujan Chandra kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=GuloMelki Mario en-aut-sei=Gulo en-aut-mei=Melki Mario kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Department of Informatics and Computer Engineering, Politeknik Elektronika Negeri Surabaya kn-affil= affil-num=7 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=Raspberry Pi kn-keyword=Raspberry Pi en-keyword=WLAN kn-keyword=WLAN en-keyword=traffic shaping kn-keyword=traffic shaping en-keyword=access point kn-keyword=access point en-keyword=fairness kn-keyword=fairness en-keyword=throughput request kn-keyword=throughput request END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue=10 article-no= start-page=369 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20221007 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Static Assignment Algorithm of Uniform Jobs to Workers in a User-PC Computing System Using Simultaneous Linear Equations en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=ZhouXudong en-aut-sei=Zhou en-aut-mei=Xudong kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HtetHein en-aut-sei=Htet en-aut-mei=Hein kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KamoyedjiAriel en-aut-sei=Kamoyedji en-aut-mei=Ariel kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=AnggrainiIrin Tri en-aut-sei=Anggraini en-aut-mei=Irin Tri kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=HuoYuanzhi en-aut-sei=Huo en-aut-mei=Yuanzhi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=SyaifudinYan Watequlis en-aut-sei=Syaifudin en-aut-mei=Yan Watequlis kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Information Technology Department, State Polytechnic of Malang kn-affil= en-keyword=UPC kn-keyword=UPC en-keyword=distributed computing platform kn-keyword=distributed computing platform en-keyword=uniform job kn-keyword=uniform job en-keyword=static assignment kn-keyword=static assignment en-keyword=linear equations kn-keyword=linear equations END start-ver=1.4 cd-journal=joma no-vol=20 cd-vols= no-issue= article-no= start-page=100583 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=202211 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=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 en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=MuneneKwenga Ismael en-aut-sei=Munene en-aut-mei=Kwenga Ismael kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=RahmanMd. Mahbubur en-aut-sei=Rahman en-aut-mei=Md. Mahbubur kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=BriantoroHendy en-aut-sei=Briantoro en-aut-mei=Hendy kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=RoySujan Chandra en-aut-sei=Roy en-aut-mei=Sujan Chandra kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Internet of Things kn-keyword=Internet of Things en-keyword=WLAN kn-keyword=WLAN en-keyword=partially overlapping channel kn-keyword=partially overlapping channel en-keyword=access point kn-keyword=access point en-keyword=transmission power kn-keyword=transmission power en-keyword=channel bonding kn-keyword=channel bonding en-keyword=non-channel bonding kn-keyword=non-channel bonding en-keyword=throughput drop kn-keyword=throughput drop END start-ver=1.4 cd-journal=joma no-vol=22 cd-vols= no-issue=17 article-no= start-page=6436 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220826 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Design and Implementation of SEMAR IoT Server Platform with Applications en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=PandumanYohanes Yohanie Fridelin en-aut-sei=Panduman en-aut-mei=Yohanes Yohanie Fridelin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=PuspitaningayuPradini en-aut-sei=Puspitaningayu en-aut-mei=Pradini kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=SukaridhotoSritrusta en-aut-sei=Sukaridhoto en-aut-mei=Sritrusta kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Department of Informatic and Computer, Politeknik Elektronika Negeri Surabaya kn-affil= affil-num=6 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=Internet of Things kn-keyword=Internet of Things en-keyword=server platform kn-keyword=server platform en-keyword=SEMAR kn-keyword=SEMAR en-keyword=IoT application system kn-keyword=IoT application system en-keyword=sensor kn-keyword=sensor en-keyword=MQTT kn-keyword=MQTT en-keyword=REST API kn-keyword=REST API END start-ver=1.4 cd-journal=joma no-vol=13 cd-vols= no-issue=5 article-no= start-page=211 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2022 dt-pub=20220420 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Proposal of the Fingerprint Optimization Method for the Fingerprint-Based Indoor Localization System with IEEE 802.15.4 Devices en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=HuoYuanzhi en-aut-sei=Huo en-aut-mei=Yuanzhi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=PuspitaningayuPradini en-aut-sei=Puspitaningayu en-aut-mei=Pradini kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HamazakiKazushi en-aut-sei=Hamazaki en-aut-mei=Kazushi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KojimaKazuyuki en-aut-sei=Kojima en-aut-mei=Kazuyuki kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=2 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=4 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=5 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=6 en-affil=Mechanical Engineering, Shonan Institute of Technology kn-affil= en-keyword=indoor localization kn-keyword=indoor localization en-keyword=fingerprint kn-keyword=fingerprint en-keyword=IEEE802.15.4 kn-keyword=IEEE802.15.4 en-keyword=LQI kn-keyword=LQI en-keyword=parameter optimization kn-keyword=parameter optimization END start-ver=1.4 cd-journal=joma no-vol=17 cd-vols= no-issue=2 article-no= start-page=140 end-page=152 dt-received= dt-revised= dt-accepted= dt-pub-year=2021 dt-pub=202145 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A proposal of recommendation function for element fill-in-Blank problems in java programming learning assistant system en-subtitle= kn-subtitle= en-abstract= kn-abstract=Purpose
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.

Design/methodology/approach
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.

Findings
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.

Originality/value
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. en-copyright= kn-copyright= en-aut-name=WintSu Sandy en-aut-sei=Wint en-aut-mei=Su Sandy kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=SyaifudinYan Watequlis en-aut-sei=Syaifudin en-aut-mei=Yan Watequlis kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=AungShune Lae en-aut-sei=Aung en-aut-mei=Shune Lae kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KaoWen-Chun en-aut-sei=Kao en-aut-mei=Wen-Chun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=2 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=4 en-affil=Department of Computer Studies, University of Yangon kn-affil= affil-num=5 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=JavaScript kn-keyword=JavaScript en-keyword=Java programming kn-keyword=Java programming en-keyword=JPLAS kn-keyword=JPLAS en-keyword=Element fill-in-blank problem kn-keyword=Element fill-in-blank problem en-keyword=Offline answering function kn-keyword=Offline answering function en-keyword=Recommendation function kn-keyword=Recommendation function END start-ver=1.4 cd-journal=joma no-vol=16 cd-vols= no-issue=2 article-no= start-page=137 end-page=149 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191023 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A proposal of calligraphy learning assistant system with letter portion practice function using projection mapping en-subtitle= kn-subtitle= en-abstract= kn-abstract=Purpose
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.
Design/methodology/approach
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.
Findings
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.
Originality/value
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. en-copyright= kn-copyright= en-aut-name=HudaSamsul en-aut-sei=Huda en-aut-mei=Samsul kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=2 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=4 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=Raspberry Pi kn-keyword=Raspberry Pi en-keyword=Calligraphy kn-keyword=Calligraphy en-keyword=Learning assistant system kn-keyword=Learning assistant system en-keyword=Projection mapping kn-keyword=Projection mapping END start-ver=1.4 cd-journal=joma no-vol=16 cd-vols= no-issue=1 article-no= start-page=115 end-page=135 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191003 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A proposal of Android Programming Learning Assistant System with implementation of basic application learning en-subtitle= kn-subtitle= en-abstract= kn-abstract=Purpose
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.
Design/methodology/approach
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.
Findings
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.
Originality/value
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. en-copyright= kn-copyright= en-aut-name=SyaifudinYan Watequlis en-aut-sei=Syaifudin en-aut-mei=Yan Watequlis kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=2 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=4 en-affil=National Taiwan Normal University kn-affil= en-keyword=Android application kn-keyword=Android application en-keyword=APLAS kn-keyword=APLAS en-keyword=JUnit kn-keyword=JUnit en-keyword=Learning system kn-keyword=Learning system en-keyword= Learning system kn-keyword= Learning system en-keyword=Test-driven development method kn-keyword=Test-driven development method en-keyword=Index terms APLAS kn-keyword=Index terms APLAS en-keyword=Java kn-keyword=Java END start-ver=1.4 cd-journal=joma no-vol=15 cd-vols= no-issue= article-no= start-page=2069 end-page=2080 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191128 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Near-Optimal Detection for Binary Tardos Code by Estimating Collusion Strategy en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=Yasui Tatsuya en-aut-sei=Yasui en-aut-mei= Tatsuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=EchizenIsao en-aut-sei=Echizen en-aut-mei=Isao kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Graduate School of Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=National Institute of Informatics kn-affil= en-keyword=fingerprinting code kn-keyword=fingerprinting code en-keyword=optimal detector kn-keyword=optimal detector en-keyword=collusion strategy kn-keyword=collusion strategy en-keyword=number of colluders kn-keyword=number of colluders en-keyword=estimator kn-keyword=estimator END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=855 end-page=864 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180719 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Proposal of Code Completion Problem for Java Programming Learning Assistant System en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Htoo Htoo Sandi Kyaw en-aut-sei=Htoo Htoo Sandi Kyaw en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Shwe Thinzar Aung en-aut-sei=Shwe Thinzar Aung en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=Hnin Aye Thant en-aut-sei=Hnin Aye Thant en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Information Science and TechnologyUniversity of Technology Yatanarpon Cyber City kn-affil= affil-num=2 en-affil=Department of Information Science and TechnologyUniversity of Technology Yatanarpon Cyber City kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering Okayama University kn-affil= affil-num=4 en-affil=Department of Electrical and Communication Engineering Okayama University kn-affil= END start-ver=1.4 cd-journal=joma no-vol=9 cd-vols= no-issue=1 article-no= start-page=47 end-page=59 dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20190528 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Enhancements of minimax access-point setup optimisation approach for IEEE 802.11 WLAN en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Kyaw Soe Lwin en-aut-sei=Kyaw Soe Lwin en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=Sumon Kumar Debnath en-aut-sei=Sumon Kumar Debnath en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Ismael Munene Kwenga en-aut-sei=Ismael Munene Kwenga en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=Rahardhita Widyatra Sudibyo en-aut-sei=Rahardhita Widyatra Sudibyo en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=3 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=4 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=5 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=6 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=7 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=wireless local area network kn-keyword=wireless local area network en-keyword=WLAN kn-keyword=WLAN en-keyword=access-point setup kn-keyword=access-point setup en-keyword=throughput estimation model kn-keyword=throughput estimation model en-keyword=parameter optimisation kn-keyword=parameter optimisation en-keyword=multiple-input multiple-output kn-keyword=multiple-input multiple-output en-keyword=MIMO kn-keyword=MIMO END start-ver=1.4 cd-journal=joma no-vol=8 cd-vols= no-issue=1 article-no= start-page=50 end-page=58 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180410 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A holding access-point assignment algorithm for IEEE802.11 wireless local-area networks en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=TajimaShigeto en-aut-sei=Tajima en-aut-mei=Shigeto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Engineering Science, Osaka University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Information Science and Technology, Osaka University en-keyword=wireless local-area network kn-keyword=wireless local-area network en-keyword=WLAN kn-keyword=WLAN en-keyword=holding access-point kn-keyword=holding access-point en-keyword=partially overlapping channel kn-keyword=partially overlapping channel en-keyword=assignment algorithm kn-keyword=assignment algorithm en-keyword=combinatorial optimisation problem kn-keyword=combinatorial optimisation problem END start-ver=1.4 cd-journal=joma no-vol=3 cd-vols= no-issue=1 article-no= start-page=30 end-page=37 dt-received= dt-revised= dt-accepted= dt-pub-year=2018 dt-pub=20180130 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Test Code Generation Method for Coding Standard Input/Output with Exception Handling in Java Programming Learning Assistant System en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Ei Ei Mon en-aut-sei=Ei Ei Mon en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KusakaRyota en-aut-sei=Kusaka en-aut-mei=Ryota kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Khin Khin Zaw en-aut-sei=Khin Khin Zaw en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Okayama University, Department of Electrical and Communication Engineering kn-affil= affil-num=2 en-affil=Okayama University, Department of Electrical and Communication Engineering kn-affil= affil-num=3 en-affil=Okayama University, Department of Electrical and Communication Engineering kn-affil= affil-num=4 en-affil=Okayama University, Department of Electrical and Communication Engineering kn-affil= affil-num=5 en-affil=National Taiwan Normal University, Department of Electrical Engineering kn-affil= en-keyword=Java programming kn-keyword=Java programming en-keyword=JPLAS kn-keyword=JPLAS en-keyword=Test code kn-keyword=Test code en-keyword=Test case kn-keyword=Test case en-keyword=Automatic generation kn-keyword=Automatic generation en-keyword=JUnit kn-keyword=JUnit END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=3 article-no= start-page=145 end-page=154 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20171229 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A design-aware test code approach for code writing problem in Java programming learning assistant system en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Khin Khin Zaw en-aut-sei=Khin Khin Zaw en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= affil-num=1 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= affil-num=2 en-affil=Graduate School of Natural Science and Technology, Okayama University kn-affil= en-keyword=Java programming learning assistant system kn-keyword=Java programming learning assistant system en-keyword=JPLAS kn-keyword=JPLAS en-keyword=design-aware test code kn-keyword=design-aware test code en-keyword=JUnit kn-keyword=JUnit en-keyword=metric plugin kn-keyword=metric plugin en-keyword=breadth-first-search kn-keyword=breadth-first-search en-keyword=BFS kn-keyword=BFS END start-ver=1.4 cd-journal=joma no-vol=2 cd-vols= no-issue=1 article-no= start-page=116 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20170727 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A software architecture for Java programming learning assistant system en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=IshiharaNobuya en-aut-sei=Ishihara en-aut-mei=Nobuya kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=2 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=3 en-affil=Department of Electrical and Communication Engineering, Okayama University kn-affil= affil-num=4 en-affil=Department of Electrical Engineering, National Taiwan Normal University kn-affil= en-keyword=JPLAS kn-keyword=JPLAS en-keyword=Java programming education kn-keyword=Java programming education en-keyword=Web application kn-keyword=Web application en-keyword= MVC model kn-keyword= MVC model en-keyword=Software architecture kn-keyword=Software architecture END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=2 article-no= start-page=248 end-page=270 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20171004 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Channel Assignment Extension of Active Access-Point Configuration Algorithm for Elastic WLAN System and Its Implementation Using Raspberry Pi en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Md. Selim Al Mamun en-aut-sei=Md. Selim Al Mamun en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=Kyaw Soe Lwin en-aut-sei=Kyaw Soe Lwin en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Md. Ezharul Islam en-aut-sei=Md. Ezharul Islam en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil=Okayama University kn-affil= affil-num=2 en-affil=Okayama University kn-affil= affil-num=3 en-affil=Okayama University kn-affil= affil-num=4 en-affil=Okayama University kn-affil= affil-num=5 en-affil=National Taiwan Normal University kn-affil= en-keyword=Elastic WLAN system kn-keyword=Elastic WLAN system en-keyword=interference minimization kn-keyword=interference minimization en-keyword=channel assignment kn-keyword=channel assignment en-keyword=active access-point configuration algorithm kn-keyword=active access-point configuration algorithm en-keyword=testbed kn-keyword=testbed en-keyword=Raspberry Pi kn-keyword=Raspberry Pi END start-ver=1.4 cd-journal=joma no-vol=7 cd-vols= no-issue=2 article-no= start-page=187 end-page=207 dt-received= dt-revised= dt-accepted= dt-pub-year=2017 dt-pub=20171004 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Minimax Approach for Access Point Setup Optimization in IEEE 802.11n Wireless Networks en-subtitle= kn-subtitle= en-abstract= kn-abstract= 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. en-copyright= kn-copyright= en-aut-name=Kyaw Soe Lwin en-aut-sei=Kyaw Soe Lwin en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=TaniguchiChihiro en-aut-sei=Taniguchi en-aut-mei=Chihiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=Khin Khin Zaw en-aut-sei=Khin Khin Zaw en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=Md. Selim Al Mamun en-aut-sei=Md. Selim Al Mamun en-aut-mei= kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=KuribayashiMinoru en-aut-sei=Kuribayashi en-aut-mei=Minoru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KaoWen-Chung en-aut-sei=Kao en-aut-mei=Wen-Chung kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= affil-num=1 en-affil=Okayama University kn-affil= affil-num=2 en-affil=Okayama University kn-affil= affil-num=3 en-affil=Okayama University kn-affil= affil-num=4 en-affil=Okayama University kn-affil= affil-num=5 en-affil=Okayama University kn-affil= affil-num=6 en-affil=Okayama University kn-affil= affil-num=7 en-affil=National Taiwan Normal University kn-affil= en-keyword=Wireless local area network kn-keyword=Wireless local area network en-keyword=access point setup kn-keyword=access point setup en-keyword=MIMO kn-keyword=MIMO en-keyword=throughput estimation model kn-keyword=throughput estimation model en-keyword=parameter optimization kn-keyword=parameter optimization END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=430 end-page=436 dt-received= dt-revised= dt-accepted= dt-pub-year=2001 dt-pub=20019 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A global routing technique for wave-steered design methodology en-subtitle= kn-subtitle= en-abstract= kn-abstract=

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 μm CMOS technology

en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SinghAmit en-aut-sei=Singh en-aut-mei=Amit kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=MukherjeeArindam en-aut-sei=Mukherjee en-aut-mei=Arindam kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SadowskaMalgorzata Marek en-aut-sei=Sadowska en-aut-mei=Malgorzata Marek kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=University of California affil-num=3 en-affil= kn-affil=University of California affil-num=4 en-affil= kn-affil=University of California en-keyword=binary decision diagrams kn-keyword=binary decision diagrams en-keyword=circuit layout CAD kn-keyword=circuit layout CAD en-keyword=flip-flops kn-keyword=flip-flops en-keyword=integrated circuit layout kn-keyword=integrated circuit layout en-keyword=network routing kn-keyword=network routing END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue= article-no= start-page=999 end-page=1004 dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=20053 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Optical-drop wavelength assignment problem for wavelength reuse in WDM ring metropolitan area networks en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IsogaiMegumi en-aut-sei=Isogai en-aut-mei=Megumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NakanishiToru en-aut-sei=Nakanishi en-aut-mei=Toru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Department of Communication Network Engineering, Okayama University affil-num=2 en-affil= kn-affil=Department of Communication Network Engineering, Okayama University affil-num=3 en-affil= kn-affil=Department of Communication Network Engineering, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Information Science and Technology, Osaka University en-keyword=metropolitan area networks kn-keyword=metropolitan area networks en-keyword=optical fibre networks kn-keyword=optical fibre networks en-keyword=telecommunication network topology kn-keyword=telecommunication network topology en-keyword=telecommunication traffic kn-keyword=telecommunication traffic en-keyword=wavelength division multiplexing kn-keyword=wavelength division multiplexing END start-ver=1.4 cd-journal=joma no-vol=1 cd-vols= no-issue= article-no= start-page= end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=200511 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Compact tree plus algorithms for application-level multicast communications in multihome networks en-subtitle= kn-subtitle= en-abstract= kn-abstract=

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.

en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=IsogaiMegumi en-aut-sei=Isogai en-aut-mei=Megumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NakanishiToru en-aut-sei=Nakanishi en-aut-mei=Toru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Osaka University, Osaka en-keyword=multicast communication kn-keyword=multicast communication en-keyword=queueing theory kn-keyword=queueing theory en-keyword=telecommunication network routing kn-keyword=telecommunication network routing END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=229 end-page=232 dt-received= dt-revised= dt-accepted= dt-pub-year=2003 dt-pub=20033 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A proposal of a minimal-state processing search algorithm for isochronous channel reuse problems in DQDB networks en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=SuganoAyako en-aut-sei=Sugano en-aut-mei=Ayako kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Communication Network Engineering, Okayama University affil-num=2 en-affil= kn-affil=Department of Communication Network Engineering, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Information Science and Technology, Osaka University en-keyword=IEEE standards kn-keyword=IEEE standards en-keyword=access protocols kn-keyword=access protocols en-keyword=channel allocation kn-keyword=channel allocation en-keyword=metropolitan area networks kn-keyword=metropolitan area networks en-keyword=performance evaluation kn-keyword=performance evaluation en-keyword=telecommunication standards kn-keyword=telecommunication standards END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=304 end-page=307 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20063 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A LECCS model parameter optimization algorithm for EMC designs of IC/LSI systems en-subtitle= kn-subtitle= en-abstract= kn-abstract=

<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>

en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NomuraYohei en-aut-sei=Nomura en-aut-mei=Yohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawashimaJun en-aut-sei=Kawashima en-aut-mei=Jun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MinamisawaYuichiro en-aut-sei=Minamisawa en-aut-mei=Yuichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=WadaOsami en-aut-sei=Wada en-aut-mei=Osami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Okayama University affil-num=5 en-affil= kn-affil=kyoto University en-keyword=RLC circuits kn-keyword=RLC circuits en-keyword=electromagnetic compatibility kn-keyword=electromagnetic compatibility en-keyword=electromagnetic interference kn-keyword=electromagnetic interference en-keyword=equivalent circuits kn-keyword=equivalent circuits en-keyword=integrated circuit design kn-keyword=integrated circuit design en-keyword=large scale integration kn-keyword=large scale integration en-keyword=linear network analysis kn-keyword=linear network analysis END start-ver=1.4 cd-journal=joma no-vol= cd-vols= no-issue= article-no= start-page=304 end-page=307 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=20063 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A LECCS model parameter optimization algorithm for EMC designs of IC/LSI systems en-subtitle= kn-subtitle= en-abstract= kn-abstract=

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.

en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=NomuraYohei en-aut-sei=Nomura en-aut-mei=Yohei kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KawashimaJun en-aut-sei=Kawashima en-aut-mei=Jun kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=MinamisawaYuichiro en-aut-sei=Minamisawa en-aut-mei=Yuichiro kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=WadaOsami en-aut-sei=Wada en-aut-mei=Osami kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Okayama University affil-num=5 en-affil= kn-affil=Kyoto University en-keyword=RLC circuits kn-keyword=RLC circuits en-keyword=electromagnetic compatibility kn-keyword=electromagnetic compatibility en-keyword=electromagnetic interference kn-keyword=electromagnetic interference en-keyword=equivalent circuits kn-keyword=equivalent circuits en-keyword=integrated circuit design kn-keyword=integrated circuit design en-keyword=large scale integration kn-keyword=large scale integration en-keyword=linear network analysis kn-keyword=linear network analysis END start-ver=1.4 cd-journal=joma no-vol=4 cd-vols= no-issue= article-no= start-page=2769 end-page=2774 dt-received= dt-revised= dt-accepted= dt-pub-year=2001 dt-pub=200110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A minimal-state processing search algorithm for satisfiability problems en-subtitle= kn-subtitle= en-abstract= kn-abstract=

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

en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=YokohiraTokumi en-aut-sei=Yokohira en-aut-mei=Tokumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=NakanishiToru en-aut-sei=Nakanishi en-aut-mei=Toru kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=TajimaShigeto en-aut-sei=Tajima en-aut-mei=Shigeto kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Okayama University affil-num=2 en-affil= kn-affil=Okayama University affil-num=3 en-affil= kn-affil=Okayama University affil-num=4 en-affil= kn-affil=Osaka University affil-num=5 en-affil= kn-affil=Osaka University, Osaka en-keyword=SAT kn-keyword=SAT en-keyword=heuristic algorithm kn-keyword=heuristic algorithm en-keyword=optimization kn-keyword=optimization en-keyword=DIMACS kn-keyword=DIMACS en-keyword= MIPS_SAT. kn-keyword= MIPS_SAT. END start-ver=1.4 cd-journal=joma no-vol=40 cd-vols= no-issue=1 article-no= start-page=78 end-page=82 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=200601 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=An Eye-Contour Extraction Algorithm from Face Image usingDeformable Template Matching en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=FunabikiNobuo en-aut-sei=Funabiki en-aut-mei=Nobuo kn-aut-name=船曳信生 kn-aut-sei=船曳 kn-aut-mei=信生 aut-affil-num=1 ORCID= en-aut-name=IsogaiMegumi en-aut-sei=Isogai en-aut-mei=Megumi kn-aut-name=磯貝愛 kn-aut-sei=磯貝 kn-aut-mei=愛 aut-affil-num=2 ORCID= en-aut-name=HigashinoTeruo en-aut-sei=Higashino en-aut-mei=Teruo kn-aut-name=東野輝夫 kn-aut-sei=東野 kn-aut-mei=輝夫 aut-affil-num=3 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=OdaMasashi kn-aut-sei=Oda kn-aut-mei=Masashi aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Grad. School of Natural Science & Tech. Okayama University affil-num=2 en-affil= kn-affil=Grad. School of Natural Science & Tech. Okayama University affil-num=3 en-affil= kn-affil=Grad. School of Inform. Science & Tech. Osaka University affil-num=4 en-affil= kn-affil=Grad. School of Inform. Science & Tech. Osaka University END