Faculty Profiles - FUJII Keisuke

Papers - FUJII Keisuke

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Player evaluation in a racket sport via deep reinforcement learning with technical and tactical contexts Reviewed Open Access

DING Ning, TAKEDA Kazuya, FUJII Keisuke

Proceedings of the Annual Conference of JSAI Vol. JSAI2022 ( 0 ) page： 1S1IS304 - 1S1IS304 2022

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japanese Society for Artificial Intelligence

<p>Evaluating the performance of players in dynamic competition plays a vital role in effective sports coaching. However, the evaluation of players in racket sports has been still difficult in a quantitative manner, because it is derived from the integration of complex tactical and technical (i.e., whole-body movement) performances. In this paper, we propose a new evaluation method for racket sports based on deep reinforcement learning, which can analyze the player's motion in more detail than the results (i.e., scores). Our method uses historical data including players' tactical and technical performance information to learn the next score probability as Q function, which is used to value players’ actions. We verified our approach by comparing various models and present the effectiveness of our method through use cases that analyze the performance of the top badminton players in world-class events.</p>

DOI： 10.11517/pjsai.jsai2022.0_1s1is304

Open Access

CiNii Research

Analysis of group behavior based on sharing heterogeneous roles in a triad using a coordinated drawing task Reviewed Open Access

Jun Ichikawa, Keisuke Fujii

Frontiers in Psychology 2022

Cooperative play classification in team sports via semi-supervised learning, International Journal of Computer Science in Sport Reviewed

Ziyi Zhang, Kazuya Takeda, Keisuke Fujii

International Journal of Computer Science in Sport 2022

Frechet and Hausdorff Kernels for Trajectory Data Analysis Reviewed

Koh Takeuchi, Masaaki Imaizumi, Shunsuke Kanda, Keisuke Fujii, Masakazu Ishihata, Takuya Maekawa, Ken Yoda, Yasuo Tabei

29th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL 2021) 2021.11

Skill Differences in a Discrete Motor Task Emerging From the Environmental Perception Phase Reviewed Open Access

Yumiko Hasegawa, Ayako Okada, Keisuke Fujii

Frontiers in Psychology Vol. 12 2021.10

Authorship：Last author Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers Media SA

Because of the challenges associated with measuring human perception and strategy, the process of human performance from perception to motion to results is not fully understood. Therefore, this study clarifies the phase at which errors occur and how differences in skill level manifest in a motor task requiring an accurate environmental perception and fine movement control. We assigned a golf putting task and comprehensively examined various errors committed in five phases of execution. Twelve tour professionals and twelve intermediate amateur golfers performed the putting task on two surface conditions: flat and a 0.4-degree incline. The participants were instructed to describe the topographical characteristics of the green before starting the trials on each surface (environmental perception phase). Before each attempt, the participants used the reflective markers to indicate their aim point from which the ball would be launched (decision-making phase). We measured the clubface angle and impact velocity to highlight the pre-motion and motion errors (pre-motion and motion phase). In addition, mistakes in the final ball position were analyzed as result errors (post-performance phase). Our results showed that more than half of the amateurs committed visual–somatosensory errors in the perception phase. Moreover, their aiming angles in the decision-making phase differed significantly from the professionals, with no significant differences between slope conditions. In addition, alignment errors, as reported in previous studies, occurred in the pre-motion phase regardless of skill level (i.e., increased in the 0.4-degree condition). In the motion phase, the intermediate-level amateurs could not adjust their clubhead velocity control to the appropriate level, and the clubhead velocity and clubface angle control were less reproducible than those of the professionals. To understand the amateur result errors in those who misperceived the slopes, we checked the individual results focusing on the final ball position. We found that most of these participants had poor performance, especially in the 0.4-degree condition. Our results suggest that the amateurs’ pre-motion and strategy errors depended on their visual–somatosensory errors.

DOI： 10.3389/fpsyg.2021.697914

Open Access

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Supervised sequential pattern mining of event sequences in sport to identify important patterns of play: An application to rugby union Reviewed Open Access

Rory Bunker, Keisuke Fujii, Hiroyuki Hanada, Ichiro Takeuchi

PLOS ONE Vol. 16 ( 9 ) page： e0256329 - e0256329 2021.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Public Library of Science (PLoS)

Given a set of sequences comprised of time-ordered events, sequential pattern mining is useful to identify frequent subsequences from different sequences or within the same sequence. However, in sport, these techniques cannot determine the importance of particular patterns of play to good or bad outcomes, which is often of greater interest to coaches and performance analysts. In this study, we apply a recently proposed supervised sequential pattern mining algorithm called safe pattern pruning (SPP) to 490 labelled event sequences representing passages of play from one rugby team’s matches in the 2018 Japan Top League season. We obtain patterns that are the most discriminative between scoring and non-scoring outcomes from both the team’s and opposition teams’ perspectives using SPP, and compare these with the most frequent patterns obtained with well-known unsupervised sequential pattern mining algorithms when applied to subsets of the original dataset, split on the label. From our obtained results, line breaks, successful line-outs, regained kicks in play, repeated phase-breakdown play, and failed exit plays by the opposition team were found to be the patterns that discriminated most between the team scoring and not scoring. Opposition team line breaks, errors made by the team, opposition team line-outs, and repeated phase-breakdown play by the opposition team were found to be the patterns that discriminated most between the opposition team scoring and not scoring. It was also found that, probably because of the supervised nature and pruning/safe-screening mechanisms of SPP, compared to the patterns obtained by the unsupervised methods, those obtained by SPP were more sophisticated in terms of containing a greater variety of events, and when interpreted, the SPP-obtained patterns would also be more useful for coaches and performance analysts.

DOI： 10.1371/journal.pone.0256329

Open Access

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Flexible prediction of opponent motion with internal representation in interception behavior Reviewed Open Access

Kazushi Tsutsui, Keisuke Fujii, Kazutoshi Kudo, Kazuya Takeda

Biological Cybernetics 2021.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

<title>Abstract</title>Skilled interception behavior often relies on accurate predictions of external objects because of a large delay in our sensorimotor systems. To deal with the sensorimotor delay, the brain predicts future states of the target based on the current state available, but it is still debated whether internal representations acquired from prior experience are used as well. Here we estimated the predictive manner by analyzing the response behavior of a pursuer to a sudden directional change of the evasive target, providing strong evidence that prediction of target motion by the pursuer was incompatible with a linear extrapolation based solely on the current state of the target. Moreover, using neural network models, we validated that nonlinear extrapolation as estimated was computationally feasible and useful even against unknown opponents. These results support the use of internal representations in predicting target motion, suggesting the usefulness and versatility of predicting external object motion through internal representations.

DOI： 10.1007/s00422-021-00891-9

Open Access

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Other Link： https://link.springer.com/article/10.1007/s00422-021-00891-9/fulltext.html

Understanding Others' Roles Based on Perspective Taking in Coordinated Group Behavior Reviewed

Jun Ichikawa, Keisuke Fujii

Proceedings of the Annual Meeting of the Cognitive Science Society Vol. 43 page： 1285 - 1291 2021.8

Extraction of swing motion contributing to prediction of shuttle drop position in badminton Reviewed

Tatsuya Yoshikawa, Kazushi Tsutsui, Kazuya Takeda, Keisuke Fujii

30th International Joint Conference on Artificial Intelligence (IJCAI-21) workshop on AI for Sports Analytics (AISA) 2021.8

Investigation of roles in group behavior using a coordinative drawing task Reviewed Open Access

Ichikawa Jun, Fujii Keisuke

Cognitive Studies: Bulletin of the Japanese Cognitive Science Society Vol. 28 ( 1 ) page： 170 - 173 2021.3

Quantitative analysis of spontaneous sociality in children's group behavior during nursery activity. Reviewed International journal Open Access

Jun Ichikawa, Keisuke Fujii, Takayuki Nagai, Takashi Omori, Natsuki Oka

PloS one Vol. 16 ( 2 ) page： e0246041 2021.2

Language：English Publishing type：Research paper (scientific journal)

Sociality is the tendency to spontaneously interact with others to establish and maintain relationships. Some approaches, including questionnaires, tests, controlled experiments, and qualitative field research, cannot capture complex social interactions, such as in children during nursery activities, because of problems with ecological validity and the labor cost of analysis. Here, we introduced a new methodology for the quantitative analysis of spontaneous social movement and investigated children's group behavior using position data. We periodically visited a nursery and recorded videos of eurhythmics, in which children move in tune with music, in different classes. The results revealed that children in the six-year-old class approached others in a short period of time (within one second) and established group behavior like that in a game of tag. It can be interpreted that such social behavior may include actions related to the cognition of anticipating others' behaviors in a complex situation. Although only a small amount of data could be acquired, this study suggests one of the characteristics of social behaviors in the classroom considering an ecological approach.

DOI： 10.1371/journal.pone.0246041

Trajectory prediction with imitation learning reflecting defensive evaluation in team sports. Reviewed

Masakiyo Teranishi, Keisuke Fujii, Kazuya Takeda

IEEE 9th Global Conference on Consumer Electronics (GCCE 2020) page： 124 - 125 2020.12

Cognition and interpersonal coordination of patients with schizophrenia who have sports habits. Reviewed International journal Open Access

Keisuke Fujii, Yujiro Yoshihara, Yukiko Matsumoto, Keima Tose, Hideaki Takeuchi, Masanori Isobe, Hiroto Mizuta, Daisuke Maniwa, Takehiko Okamura, Toshiya Murai, Yoshinobu Kawahara, Hidehiko Takahashi

PloS one Vol. 15 ( 11 ) page： e0241863 2020.11

Language：English Publishing type：Research paper (scientific journal)

Team sports activities are effective for improving the negative symptoms and cognitive functions in patients with schizophrenia. However, the interpersonal coordination during the sports and visual cognition of patients with schizophrenia who have team sports habits are unknown. The main objectives of this study were to test two hypotheses: first, patients with schizophrenia perform the skill requiring ball passing and receiving worse than healthy controls; and second, the patients will be impaired in these functionings in accordance with the previous studies regarding schizophrenia in general. Twelve patients with schizophrenia and 15 healthy controls, who had habits in football, participated in this study. The participants performed three conventional cognitive tests and a 3-vs-1 ball possession task to evaluate their interpersonal coordination. The results showed that in the 3-vs-1 possession task, the displacement in the pass angle for the patients was significantly smaller than that for the control. The recall in the complex figure test, the performance in the trail making test, and that in the five-choice reaction task for the patients were worse than those for the control. Moreover, we found the significant partial correlations in the patients between the extradimensional shift error and the pass angle as well as between the time in the trail making test and the displacement in the pass angle, whereas there was no significant correlation in the control group. This study clarified the impaired interpersonal coordination during team sports and the visual cognition of patients with schizophrenia who have team sports habits.

DOI： 10.1371/journal.pone.0241863

Succinct Trit-array Trie for Scalable Trajectory Similarity Search. Reviewed

Shunsuke Kanda, Koh Takeuchi, Keisuke Fujii, Yasuo Tabei

Proceedings of 28th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL 2020) page： 518 - 529 2020.11

Proposal of a research approach for discussion of a dynamic coordination mechanism: Investigation of anticipating others' behaviors and adaptation through quantitative analysis of group behavior Reviewed Open Access

Ichikawa Jun, Fujii Keisuke

Cognitive Studies: Bulletin of the Japanese Cognitive Science Society Vol. 27 ( 3 ) page： 377 - 385 2020.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japanese Cognitive Science Society

<p>In this paper, we propose a research approach that is used in cognitive science to investigate more complex coordination mechanisms between three or more people. That is, we propose an approach that uses position data to quantitatively analyze group behavior and to link these characteristics with the cognition of anticipating others' behaviors. It is important for coordination to anticipate others' behaviors and to adapt one's own body movement to others based on anticipation. We highlight previous studies on problem solving and learning in cognitive science which have investigated interaction processes from verbal protocols during task implementation and indicated the importance of understanding others' perspectives. Additionally, recent cognitive models of estimating others' intentions and anticipating others' behaviors during interactions using non-verbal information such as eye movement, posture, and gesture, have been investigated. Considering these previous studies, we focus on group behavior and propose to apply the new approach mentioned above to discuss a mechanism of more complex coordination. We also refer to some studies of biological group behaviors in biology, artificial life, and sports science, and demonstrate a potential issue that such papers did not focus on the cognition related to coordinative group behaviors. This paper illustrates an example of discussing interactions with others, to which the new approach is applied. Our previous study here analyzed children's group behavior during nursery activities using position data and linked these characteristics with the cognitive development of anticipating others' behaviors based on spontaneous sociality. However, it is difficult to investigate some details of group behavior due to the limitation of field measurement, for example, the accuracy of a child's anticipation and whether a child moved based upon anticipation. In future work, it is important to analyze controlled group behavior and to indicate accuracy of individuals' anticipation from movement data to solve these problems.</p>

DOI： 10.11225/cs.2020.026

Open Access

CiNii Research

COGNITION AND SOCIAL BEHAVIORS IN SPORTS FOR PATIENTS WITH SCHIZOPHRENIA ENGAGED IN SPORTS HABITS Reviewed

Yoshihara Yujiro, Fujii Keisuke, Murai Toshiya, Takahashi Hidehiko

SCHIZOPHRENIA BULLETIN Vol. 46 page： S128 - S128 2020.4

Practice Motions Performed During Preperformance Preparation Drive the Actual Motion of Golf Putting Reviewed Open Access

Yumiko Hasegawa, Akito Miura, Keisuke Fujii

Frontiers in Psychology Vol. 11 page： Article 513 2020.3

Practice Motions Performed During Preperformance Preparation Drive the Actual Motion of Golf Putting Reviewed Open Access

Yumiko Hasegawa, Akito Miura, Keisuke Fujii

Frontier in Psychology Vol. 11 ( 513 ) page： https://doi.org/10.3389/fpsyg.2020.00513 2020.3

Dynamic mode decomposition via dictionary learning for foreground modeling in videos Reviewed

Israr Ul Haq, Keisuke Fujii, Yoshinobu Kawahara

15th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISAPP'20) Vol. 5 ( - ) page： 476-483 2020.3

Physically-interpretable classification of network dynamics for complex collective motions Reviewed Open Access

Keisuke Fujii, Naoya Takeishi, Motokazu Hojo, Yuki Inaba, Yoshinobu Kawahara

Scientific Reports Vol. 10 ( 3005 ) page： https://doi.org/10.1038/s41598-020-58064-w 2020.2

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Papers - FUJII Keisuke