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Mitigating Self-Turn-On in Scaled CSTBT: A Focus on Poly-Si Resistivity
Get PDFScaled trench IGBTs, especially with carrier stored layer (CSTBT) face self-turn-on challenges at high dVce/dt (or) di/dt due to lower gate threshold voltage Vge(th). This issue is intensified by the poly silicon (poly-Si) resistivity of split gate electrodes. Present work examines the impact of poly-Si resistivity on self-turn-on and proposes a split-less dummy CSTBT to effectively mitigate self-turn-on us-ing TCAD simulation.conference pape
Stray inductance influence on switching waveform design with gate charge control for power MOSFETs
Get PDFActive gate drive (AGD) is a technique to improve the switching behavior of power devices. Digital AGD, which is AGD assisted by digital hardware, enables precise control of the switching waveform of the power device and makes it easy to reach the optimal waveform. However, considerable computational resources and time are required to find a suitable gate drive condition from the exponentially increased number of candidates. A switching waveform design method has been proposed, which solves the gate drive waveform from a designed switching waveform with a deterministic approach. This paper experimentally investigates the influence of stray inductance on the method since the stray inductance cannot be completely eliminated in practical power converters.
A simple and wide-band voltage control current source circuit was built to generate a 100 ns-wide gate charge pulse for measuring the voltage and current responses. The measured switching voltage waveform of a Si MOSFET driven by the gate drive waveform computed using this method demonstrated good agreement with the designed waveform. The impact of stray inductance on the accuracy of the switching waveform design based on the proposed method was examined through simulation. Additionally, the requirements for the performance of digital hardware when the method is implemented into a practical system are estimated.journal articl
Preface to Volume 4: Evolving Personalized Learning Environments
Get PDFA joint international open-access journal, Information and Technology in Education and Learning (ITEL), was launched in 2021 by two academic societies in Japan— the Japan Society for Educational Technology (JSET) and the Japanese Society for Information and Systems in Education (JSiSE). The scope of the journal covers a wide range of disciplines, such as humanities, social sciences, science and engineering, learning sciences, educational psychology, cognitive science, information science, and artificial intelligence (AI). Three years after the journal’s launch, two societies and the editorial board established the ITEL Outstanding Paper Award and presented the first award this year. The award aims to recognize outstanding research, promote various research activities, and encourage the submission of research papers. It is conferred every two years, selecting from papers in the following categories: regular, practice, development, and review. For the inaugural ITEL Outstanding Paper Award, one paper was selected from 13 papers published in Volumes 1 and 2. The awarded paper, title “Teachers’ Autonomy Support in Synchronous Online Learning Environments,”[1] addresses the challenges educators and learners encounter in maintaining autonomous learning and motivation in synchronous online education—a format widely adopted during the COVID-19 pandemic. The paper was endorsed as beneficial in the current era of diverse learning modalities, including face-to-face, online, and hybrid formats, and was recognized as deserving of the award.journal articl
PSPコースへのプロダクトライン技法の適用
Get PDF著者は複数の大学院で個人レベルのソフトウェア開発プロセスPSPのトレーニングコースの講義を担当してきた．例えばその一つの九州工業大学大学院では実践的人材育成の一環として個人/チームの開発プロセスPSP/TSPiの教育を行い，大学院学生レベルでも生産性を落とさずに品質向上を達成するなどの実績をあげている．しかしながらそのようなコースの実施への取り組み方は大学院間で一様ではなく，コロナ禍の影響下での実施方式にも相違があった．さらに，ソフトウェア開発を取り巻く環境，大学に期待される社会的役割の変化などにより，求められるソフトウェアプロセスやその教育の多様性も増している．そのような状況に系統的に対応するために，ソフトウェアプロダクトライン技法をPSPコースに適用する．これまでもソフトウェアプロセスにプロダクトラインの技法を適用する取り組みはなされているが本研究は大学でのプロセスの教育・研究に焦点を当てている点に特徴がある．journal articl
人物の重なりに対する頑健性向上のためのマスク処理を用いた姿勢推定
Get PDF姿勢推定技術は，画像や動画中の人物の骨格を推定する技術であり，単純な物体検出を適用しても解決が困難なタスクへの応用が期待される．本研究では，人物の重なりによって誤った人物へ骨格が出力される問題に対し，姿勢推定により得られた骨格によるマスク処理を用いることで，人物の重なりに頑健な姿勢推定手法を提案する．人物の重なりに着目した姿勢推定用データセットを用いた実験により，提案手法の有効性を確認した．conference pape
Robust Mobility Performance of Lunar Exploration Rovers under Multiple Wheel Failure Scenarios
Get PDFThis paper presents the mobility performance analysis results of two four-wheeled lunar rovers with limited resources. The experiments were conducted using two different wheel designs in rolling and inching locomotion, multiple configurations, and failure scenarios. The results establish a resilience assessment of the robots’ mobility using a one-way clutch mechanism. The study shows results on non-failure, three-wheel, two-wheel, one-wheel, and complete drive actuator failure scenarios. Distance traveled, slip ratio, energy consumption, and the possibility of reconfiguration are evaluated and compared for each case, demonstrating the robots’ resilience in challenging lunar terrains and suitability for forthcoming lunar construction missions.othe
An Efficient State-Saving Mechanism for Out-of-band Container Migration
Get PDFMany clouds provide containers as lightweight virtu-alized environments inside virtual machines (VMs). Containers can be migrated between source and destination VMs for vari-ous reasons such as load balancing. However, the performance of container migration is largely degraded by the load and vir-tualization overhead of VMs because the migration mechanism runs inside VMs. Conversely, the performance of containers is largely affected by the load of container migration. This paper proposes OVmigrate to enable out-of-band container migration, which migrates a container running inside a VM from the outside of the VM. OVmigrate analyzes and obtains the states of a container in the memory of the source VM using a technique called VM introspection. It enables the migration mechanism outside a VM to independently save the states of a container running inside the VM. We have implemented OVmigrate for Linux and KVM and compared the performance of state saving with the existing tool called CRIU running inside the VM.journal articl
Chemical Sensor Technologies for Sustainable Development: Recent Advances, Classification, and Environmental Monitoring
Get PDFOne of the significant issues of concern in recent times is detecting, quantifying, and monitoring various chemical contaminants in the environment. Numerous inorganic and organic substances are discharged into the environment from various anthropogenic activities, thereby polluting the ecosystems' air, water, soil, and other components. These contaminants have been documented to have deleterious effects on humans, animals, and the environment. Therefore, the need for monitoring and continual quantification of the contents of these contaminants in various environmental matrices becomes paramount. Many diverse sensors are fabricated for multiple utilizations, including liquids and gas sensors, wireless sensors, electronic tongues, and noses for detecting volatile airborne substances, pollutants, and effluents. This review focuses on cutting-edge technology used in chemical sensors for environmental protection and sustainable development. It also discusses the fabrication and development of chemical sensors and their working principles. In addition, highlights about the applications of chemical sensors in environmental monitoring are also elaborated. This review article discusses emerging sensor technologies and their application in ecological monitoring. Further, the recognition of chemical warfare agents and homeland security applications with the help of bioelectronic nose and tongue is discussed. Finally, some challenges associated with chemical sensors and future trends are also attempted.journal articl
Proposal of a Method for Measuring Similarity between Swarm Intelligence Optimziation Methods
Get PDFIn this paper, we aim to quantitatively classify the vast number of swarm intelligence optimiza-(breakpoint)tion methods, and propose to express the similarity between two swarm intelligence optimization methods as the quantitative difference between the environments (fitness functions) that make the two solution search processes similar. We also propose a framework for measuring the similarity of methods based on this idea. Furthermore, we use this framework to quantitatively compare the two swarm intelligence opti-(breakpoint)mization methods and quantitatively show the differences between the methods. However, the comparison shows that the similarity is not high between similar methods with slightly different parameter values. The reason for this result is thought to be due to the method for measuring the similarity between the two solution search processes, and we show that improving the method for measuring similarity is a future challenge.journal articl
Real-time Support for Solution Search in Human-based Evolutionary Computation
Get PDFWe propose a method to extract important words common to good solution candidates in human-based evolutionary computation, like building blocks in genetic algorithms, and present them to the participants in a realtime manner. We also propose a method to obtain and present words similar to the important ones. Furthermore, we propose a method to measure the similarity between participants using the important words for each participant and present it to the participants. All of the proposed methods help participants solve problems by reducing the cognitive load of finding key words and persons. We implement those methods into a human-based evolutionary computation system and evaluate the proposed methods through human subject experiments using the system. The experimental results show that although the evaluation result to the outputs from the system incorporating the methods by a third party is not so good, the system is shown to be useful for participants to create solutions.journal articl