研究等業績 - 原著論文 - 藤原 克哉
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磁気式モーションキャプチャ装置を用いた没入型VR向けタンジブル手書きシステムの開発と評価
藤原 克哉, 安藤 遼馬, 水戸部 一孝
ヒューマンインタフェース学会論文誌 ( ヒューマンインタフェース学会 ) 26 ( 2 ) 263 - 272 2024年05月 [査読有り]
研究論文（学術雑誌） 国内共著
<p>We have developed a Tangible Hand-writing System for VR using a magnetic motion capture device and an immersive HMD, which can be operated intuitively by finger touch. In order to evaluate the usability of this system in comparison with a tablet device, we constructed two types of tracing measurement systems, a tangible-type system and a tablet-type system. We conducted an experiment to measure the tracing task of Kanji characters at two different writing speeds. The results showed that the tangible system was superior in subjective evaluation by the participants and in a comparison between starting point gaps.</p>
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Development of a VR Training System for Saito's Music Conducting Method
Fujiwara Katsuya, Sano Fumiya, Mitobe Kazutaka
IEEJ Transactions on Electrical and Electronic Engineering ( IEEJ Transactions on Electrical and Electronic Engineering ) 19 ( 2 ) 187 - 192 2024年02月 [査読有り]
研究論文（学術雑誌） 国内共著
It is important for university students studying elementary music education to master basic conducting gestures. We have developed a VR training system for self‐study of Saito's music conducting method. The system uses a depth camera and magnetic motion capture system to measure hand movements, and an HMD to superimpose the teacher's hand on the trainee's own hand. With the system, trainee can self‐study while visually and three‐dimensionally checking the motion and timing of the teacher's and the trainee's own hand gestures. In this paper, we describe an evaluation experiment with our system. The results showed that the VR environment is effective for learning three‐dimensional movements, and that the addition of a visual line display function for trajectories, a function to display trajectories from different viewpoints, and a replay function improves the learning effect. Specifically, the results of a short training session of 5 min revealed that the developed system was effective in bringing 75% of the trainees closer to the teacher's gesture. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.
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Yo Sasaki, Katsuya Fujiwara, Kazutaka Mitobe
Accident Analysis & Prevention ( Accident Analysis and Prevention ) 194 2024年01月 [査読有り]
研究論文（学術雑誌） 国内共著
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Detection of Mild Cognitive Impairment Using a Spiral Drawing Test
Katsuya Fujiwara, Kenta Matsuhashi, Kazutaka Mitobe
Journal of Advanced Computational Intelligence and Intelligent Informatics ( Fuji Technology Press Ltd. ) 27 ( 5 ) 907 - 914 2023年09月 [査読有り]
研究論文（学術雑誌） 国内共著
Information and communication technology-based monitoring services for the elderly can be improved by using a monitoring function that automatically detects cognitive decline. Therefore, we developed a system that provides a brief screening for mild cognitive impairment (MCI). This screening is performed by measuring the performance of two tasks completed simultaneously on a tablet device, such as drawing a spiral and counting color changes. First, we used this system to measure and analyze three groups: elderly persons suspected of having MCI, elderly persons with no cognitive impairment, and healthy young adults. We extracted evaluation parameters relevant for determining MCI through analysis. Furthermore, we developed a detection method using the evaluation parameters and performed an evaluation. Cross-validation revealed that the sensitivity and specificity of this method were 90.0% and 75.0%, respectively.
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Sachiko Makabe, Katsuya Fujiwara, Yu Kume, Midori Kaga, Nobuko Munemura, Shoko Kemuyama, Kazutaka Mitobe
SN Social Sciences ( Springer Science and Business Media LLC ) 2 ( 5 ) 2022年05月 [査読有り]
研究論文（学術雑誌）
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Development of a Roadway-Crossing simulator for actual walking and evaluation of pedestrian behavior
Yuta Uchibori, Naoto Handa, Katsuya Fujiwara, Kazutaka Mitobe
IEEJ Transactions on Electrical and Electronic Engineering ( IEEJ Transactions on Electrical and Electronic Engineering ) 16 ( 12 ) 1612 - 1617 2021年08月 [査読有り]
研究論文（学術雑誌） 国内共著
Pedestrians accounted for 36.6% of traffic accident fatalities in Japan (2019). Elderly pedestrians are often involved in such accidents while crossing a road. In order to investigate the characteristics of pedestrians who are prone to such accidents, we developed a ‘Roadway-Crossing Simulator for actual walking’. The simulator projects a virtual traffic environment that is accurately reproduced in size and shape by eight projectors on 8.0-m-wide screens placed on both sides of a pedestrian. The simulator can motion-capture the head, center of the scapula, and hips of a crossing pedestrian. In this study, we measured and analyzed the crossing behaviors of 10 young and 20 elderly people in a 7.5-m section from a roadside zone before entering the road to the other end of the crosswalk. We report from this virtual traffic scenario the ‘Traffic accident incidence rate’, ‘Walking speed’, ‘Distance to pedestrians and vehicles’, ‘Inter-vehicle selection ratio’ and ‘Elapsed time at roadside zone and roadway’. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
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Reliability and validity of the electronic version of the short questionnaire to assess health-enhancing physical activity (E-SQUASH)
Sachiko Makabe, Hidetomo Saito, Katsuya Fujiwara, Yu Kume, Yuko Akagawa, Wanda Wendel-Vos and Kazutaka Mitobe
International Journal of Science and Research Archive ( GSC Online Press ) 2 ( 1 ) 039 - 046 2021年02月 [査読有り]
研究論文（学術雑誌） 国際共著
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Development of a VR Simulator for Training of Posterior Cervical Spine Fusion Surgery
Katsuya FUJIWARA, Tomoya OIKAWA, Yoshinori ISHIKAWA, Kazutaka MITOBE
IEEJ Transactions on Electrical and Electronic Engineering ( IEEJ Transactions on Electrical and Electronic Engineering ) 15 ( 8 ) 1242 - 1243 2020年08月 [査読有り]
研究論文（学術雑誌） 国内共著
It is important to avoid iatrogenic injuries of nerves and blood vessels during the pedicle screw insertion stage of posterior cervical spine decompression and fusion surgery. First, it is necessary to determine the length and angulation of the pedicle screws for safety and stability. Second, it is necessary to drill precise preparation holes for the pedicle screws using a pedicle probe. In this work, we developed a VR training system for pedicle screw planning and basic drilling skills. The VR system was built with a pen-style haptic device and a head-mounted display. Trainees used the haptic pen as a virtual pedicle probe. In order to simulate bone hardness and stress accumulation at the virtual pedicle probe tip in the virtual surgery, we developed a voxel-based bone drilling simulator. To reduce the heavy load required for voxel processing, the simulator was constructed as a hybrid system that included a removal volume voxel model for drilling areas and a fixed polygonal mesh model for other areas. 3D models of a cervical spine were generated from CT scan images of a patient. This paper evaluated the system through a subjective evaluation by a specialist and via the training results for novice trainees. We discuss the evaluation results and training effectiveness with the simulator. (c) 2020 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.
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Universal Testing for Linear Feed-Forward/Feedback Shift Registers
Hideo FUJIWARA, Katsuya FUJIWARA, Toshinori HOSOKAWA
IEICE Transactions on Information and Systems ( The Institute of Electronics, Information and Communication Engineers ) E103D ( 5 ) 1023 - 1030 2020年05月 [査読有り]
研究論文（学術雑誌） 国内共著
<p><i>Linear feed-forward/feedback shift registers</i> are used as an effective tool of testing circuits in various fields including built-in self-test and secure scan design. In this paper, we consider the issue of testing linear feed-forward/feedback shift registers themselves. To test linear feed-forward/feedback shift registers, it is necessary to generate a test sequence for each register. We first present an experimental result such that a commercial ATPG (automatic test pattern generator) cannot always generate a test sequence with high fault coverage even for 64-stage linear feed-forward/feedback shift registers. We then show that there exists a <i>universal</i> test sequence with 100% of fault coverage for the class of linear feed-forward/feedback shift registers so that no test generation is required, i.e., the cost of test generation is zero. We prove the existence theorem of universal test sequences for the class of linear feed-forward/feedback shift registers.</p>
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Feature Extraction of Mild Cognitive Impairment Using a Dual-Task of Drawing and Counting Test
Katsuya FUJIWARA, Hidenori KANO, Kazutaka MITOBE
Journal of Advanced Computational Intelligence and Intelligent Informatics ( Journal of Advanced Computational Intelligence and Intelligent Informatics ) 23 ( 5 ) 874 - 882 2019年09月 [査読有り]
研究論文（学術雑誌） 国内共著
From the perspective of preventive care, a monitoring function that detects a decline in cognitive function would be useful as an information and communications technology (ICT) based service for watching over elderly people. We developed a system that evaluates cognitive functioning by simultaneously measuring dual tasks using a tablet computer. The tasks comprised a spiral drawing task and a color change counting task. The objective of this research is feature extraction of mild cognitive impairment (MCI) using this system. To do so, we compared the results of dual task tests for three participant groups: elderly people with suspected MCI, healthy elderly people, and healthy young people. The analyses were based on the amount of time required for drawing each section and the drawing velocity. The results indicate a significant difference between the MCI elders and the other two groups regarding the amount of time required for drawing the section close to the center of the spiral if the difficulty of the test’s sub-task is adjusted.
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Synthesis and Enumeration of Generalized Shift Registers for Strongly Secure SR-Equivalents
Hideo FUJIWARA, Katsuya FUJIWARA
IEICE Transactions on Information and Systems ( The Institute of Electronics, Information and Communication Engineers ) E100D ( 9 ) 2232 - 2236 2017年09月 [査読有り]
研究論文（学術雑誌） 国内共著
In our previous work, we introduced new concepts of secure scan design; shift register equivalent circuits (SR-equivalents, for short) and strongly secure circuits, and also introduced generalized shift registers (GSRs, for short) to apply them to secure scan design. In this paper, we combine both concepts of SR-equivalents and strongly secure circuits and apply them to GSRs, and consider the synthesis problem of strongly secure SR-equivalents using GSRs. We also consider the enumeration problem of GSRs that are strongly secure and SR-equivalent, i.e., the cardinality of the class of strongly secure SR-equivalent GSRs to clarify the security level of the secure scan architecture.
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Using Finger Dexterity in Elderly and Younger People to Detect Cognitive Decline
Katsuya Fujiwara, Hiroyuki Fujii, Kazutaka Mitobe
Journal of Advanced Computational Intelligence and Intelligent Informatics ( Journal of Advanced Computational Intelligence and Intelligent Informatics ) 21 ( 2 ) 330 - 336 2017年03月 [査読有り]
研究論文（学術雑誌） 国内共著
Because the number of elderly people is rapidly growing, using information and communication technology (ICT) for services to watch single-elder-person households has been attracting attention. Most of these services are aimed at detecting elders' abnormalities. They could become more effective, from the preventive-medicine point of view, if additional functions were added to watch for any decline in the elders' cognitive functions. In this paper, we describe a method for detecting minor declines in elders' cognitive functions, which they may not be aware of, by measuring and analyzing their spiral-tracing ability using a tablet device. We developed such a measurement/ analysis system and applied it to three groups of test participants: young, non-frail elders, and frail elders. This paper first describes the method for analyzing the numbers of out-of-orbit tracing attempts, the numbers of uncompleted attempts, the required time, and the angular velocities, and then refers to these tasks to reveal the elders' characteristics from the analytic results.
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若年者と高齢者を対象とした描画・計数作業の二重課題による評価手法の提案
藤原克哉, 狩野秀典, 水戸部一孝
ヒューマンインタフェース学会論文誌 19 ( 1 ) 25 - 29 2017年02月 [査読有り]
研究論文（学術雑誌） 国内共著
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Realization of SR-Equivalents Using Generalized Shift Registers for Secure Scan Design
Hideo Fujiwara, Katsuya Fujiwara
IEICE Transactions on Information and Systems E99.D ( 8 ) 2182 - 2185 2016年08月 [査読有り]
研究論文（学術雑誌） 国内共著
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Properties of Generalized Feedback Shift Registers for Secure Scan Design
Hideo Fujiwara, Katsuya Fujiwara
IEICE Transactions on Information and Systems E99.D ( 4 ) 1255 - 1258 2016年04月 [査読有り]
研究論文（学術雑誌） 国内共著
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Strongly Secure Scan Design Using Generalized Feed Forward Shift Registers
Hideo Fujiwara, Katsuya Fujiwara
IEICE Transactions on Information and Systems 98(10) 1852-1855 98 ( 10 ) 1852 - 1855 2015年10月 [査読有り]
研究論文（学術雑誌） 国内共著
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Generalized Feed Forward Shift Registers and their Application to Secure Scan Design
Katsuya Fujiwara, Hideo Fujiwara
IEICE Transactions on Information and Systems E96-D ( 5 ) 1125 - 1133 2013年05月 [査読有り]
研究論文（学術雑誌） 国内共著
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Secure and Testable Scan Design Utilizing Shift Register Quasi-Equivalents
Katsuya Fujiwara, Hideo Fujiwara, Hideo Tamamoto
IPSJ Transactions on System LSI Design Methodology 6 27 - 33 2013年02月 [査読有り]
研究論文（学術雑誌） 国内共著
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Differential Behavior Equivalent Classes of Shift Register Equivalents for Secure and Testable Scan Design
Katsuya FUJIWARA, Hideo FUJIWARA, Hideo TAMAMOTO
IEICE TRANSACTIONS on Information and Systems E94-D ( 7 ) 1430 - 1439 2011年07月 [査読有り]
研究論文（学術雑誌） 国内共著
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セキュアスキャン設計のためのシフトレジスタ等価回路の列挙と合成
藤原 克哉, 藤原 秀雄, オビエン マリー エンジェリン, 玉本 英夫
電子情報通信学会論文誌D-I J93-D ( 11 ) 2426 - 2436 2010年11月 [査読有り]
研究論文（学術雑誌） 国内共著