The University of Shiga Prefecture · Faculty of Engineering · 准教授

Research keywordsComputer Vision・Statistical Image Processing・信号処理・統計的画像処理

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• In-vacuum active colour sensor and wireless communication across a vacuum-air interface2021 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Scientific Reports © 2021, The Author(s). In situ sensing with wireless digital-data transfer is a potential processing scheme that works very closely to the location of an event monitored by a sensor and converts the sensor’s raw output into digitized and informative small-volume bits, as suggested by recent proposals for edge computing and the Internet of Things (IoT). Colour perception may be a target of in situ sensor data acquisition; however, in contrast to from other sensing devices, colour sensors that detect visible light signals are usually located away from light-emitting sources, collecting light transmitting through the space and attenuating it in some manner. For example, in a vacuum chamber whose gas pressure is much less than the ambient atmosphere in which the sensors usually work, there are many veiled light sources, such as discharge plasma, for various industrial purposes including nanoscale manufacturing. In this study, we designed an in-vacuum colour sensor that can work with analogue-to-digital conversion and transfer data by wireless communication; this sensor is active in a low-pressure plasma chamber, detecting light signals and transferring them to a personal computer located outside the vacuum chamber. In addition to detecting lights with controlled spectra from outside successfully, we achieved complete operation of our in-vacuum active sensor for plasma emissions generated at 100 Pa. Comparing the signals with data from simultaneous monitoring by a monochromator, we established that the recorded signals arose from the plasma, confirming successful direct detection of low-pressure plasma emissions without any filtering effects between the sensor and the target object. DOI： 10.1038/s41598-020-80501-z Scopus その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85099396381&origin=inward
• Order Estimation of Markov-Chain Processes in Complex Mobility Network Embedded in Vehicle Traces2021 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Studies in Computational Intelligence © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG. Vehicle mobility in urban traffic systems is complex, partly because it reflects mobility of a human who drives a vehicle, and partly because it depends on many roles which the vehicle plays. Previous studies on human mobility revealed that it includes Lévy-flights-like motions and memoryless deterministic walks as well as random walks, but the mobility of vehicles may be more biased due to their functions. Focusing our research target on a sightseeing vehicle with sufficiently limited functions, we show a method to measure regularity of visitation patterns, quantified by order(s) of Markov chains in their mobility. Graphs of higher-order Markov chains, which are representatives of mobility in a network style, possess statistical properties; in our observation dataset, they include degree distributions similar to scale-free networks. The detection of mobility in real social experiments, which is also assumed on these graphs, yields the order of Markov chains inside it with its comparison with the results of agent-based simulations. Centrality indices of the mobility networks well coincide with prediction of these analytical and numerical results. DOI： 10.1007/978-3-030-65351-4_19 Scopus その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85101814485&origin=inward
• Statistics of Growing Chemical Network Originating from One Molecule Species and Activated by Low-Temperature Plasma2021 · 記述言語： 英語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： Studies in Computational Intelligence © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG. Chemistry in plasma is complicated because it has so many reactions in parallel and in series. A complex network is suitable for the visualization and the analysis of its complexity. A numerical calculation based on hundreds of rate equations is a typical tool for plasma chemistry, but such a computational process does not clarify the undergoing physical and chemical properties that stabilize many industrial plasma processes for a number of applications. In this study, we focus on low-temperature plasma in which high-energy electrons are activators for chemical reactions, and investigate the origin of the stability by examining the statistical properties of networks for silane (SiH4 ) plasma. There is only one seed species in the initial space, SiH4, which is surrounded by high-energy electrons. SiH4 is decomposed into several fragments composed of Si and/or H atoms with possible charges, and such radical and ion species are decomposed or synthesized into other species, leading to the formation of temporal reaction networks in chemistry. With the effects of rate constants that determine chemical reaction rates, we create temporal networks and observe preferential attachments that induce a new reaction in a transient state. The centrality indices for participant species and degree distributions reveal what is occurring in this complex system, and during the sequential process we observe an exponential-tail degree distribution, which is a significant source of reaction stability. DOI： 10.1007/978-3-030-65351-4_32 Scopus その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85101815755&origin=inward
• 簡易型嚥下評価システムの構築に向けてー嚥下音と頸部深度画像を併用した嚥下評価手法の開発ー2020 · 記述言語： 日本語 掲載種別： 研究論文（学術雑誌） 出版者・発行元： 北隆館 参加形態： 共同（主担当）

• 距離画像を用いた行動分析2011 · 撮像デバイスの発達により従来のRGBカメラだけでなく，カメラから撮影対象までの距離が測定できるカメラが容易に利用できるようになりました．測定された距離から対象物体の形状が把握でき，その形状がどのように変化するかも捉えることができます．これを利用することにより，画像による人間行動の分析が容易になります．現在歩行者の検出と注視方向の推定を行うアルゴリズムを開発しています．
• センサー情報を用いた行動解析2011 · 現在普及しているスマートフォンには，加速度センサーや角速度センサー，地磁気センサーといった様々なセンサーが搭載されています．これらのセンサー情報を収集・統合することによりスマートフォンを所持している人の行動や置かれている状況が判定できると考えられます．これを応用して異常事態の検出や日常生活での健康管理に役立てていけるシステムの開発を目指しています．
• Kinectによる物体の体積推定2011 · Kinectは距離画像を出力できる安価なデバイスとして普及しています．これを用いて物体の体積をできるだけ正確に測定できる手法を検討しています．一つの応用としては浮腫部分の体積測定が考えられます．従来看護師により巻尺で測定した結果から体積換算を行っていましたが，Kinect一つで自分で浮腫部分の体積測定が可能になり，在宅での治療や手当の効果を継続的に確認していくことができます．
• 信号比によるブラインド信号分離2006 · 2006年4月 - 2010年7月

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