Learning new motor tasks from physical interactions is an important goal for both robotics and machine learning. However, when moving beyond basic skills, most monolithic machine learning approaches ...fail to scale. For more complex skills, methods that are tailored for the domain of skill learning are needed. In this paper, we take the task of learning table tennis as an example and present a new framework that allows a robot to learn cooperative table tennis from physical interaction with a human. The robot first learns a set of elementary table tennis hitting movements from a human table tennis teacher by kinesthetic teach-in, which is compiled into a set of motor primitives represented by dynamical systems. The robot subsequently generalizes these movements to a wider range of situations using our mixture of motor primitives approach. The resulting policy enables the robot to select appropriate motor primitives as well as to generalize between them. Finally, the robot plays with a human table tennis partner and learns online to improve its behavior. We show that the resulting setup is capable of playing table tennis using an anthropomorphic robot arm.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Action recognition is one of the challenging video understanding tasks in computer vision. Although there has been extensive research in the task of classifying coarse-grained actions, existing ...methods are still limited in differentiating actions with low inter-class and high intra-class variation. Particularly, the table tennis sport that involves shots of high inter-class similarity, subtle variations, occlusion, and view-point variations. While a few datasets have been available for event spotting and shot recognition, these benchmarks are mostly recorded in a constrained environment with a clear view/perception of shots executed by players. In this paper, we introduce a Table tennis shots 1.0 dataset consisting of 9000 videos of 6 fine-grained actions collected in an unconstrained manner to analyze the performance of both players. To effectively recognize these different types of table tennis shots, we propose an adaptive temporal aggregation method that can handle the temporal interactions concerning the subtle variations among shots and low inter-class variations. Our method consists of two components, namely, (i) feature extraction module and (ii) temporal aggregation network. The feature extraction module is a 3D convolutional neural network (3D-CNN) that captures the spatial and temporal characteristics of table tennis shots. Here we propose to replace the final global average pooling layer (GAP) with the temporal aggregation network to overcome the loss of motion information due to averaging of temporal features. This temporal aggregation network utilizes the attention mechanism of bidirectional encoder representations from Transformers (BERT) to model the significant temporal interactions among the shots effectively. We demonstrate that our proposed approach improves the performance of existing 3D-CNN methods by ≈10% on the Table tennis shots 1.0 dataset.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Motor expertise acquired during long-term training in sports enables top athletes to predict the outcomes of domain-specific actions better than nonexperts do. However, whether expert players encode ...actions, in addition to the concrete sensorimotor level, also at a more abstract, conceptual level, remains unclear. The present study manipulated the congruence between body kinematics and the subsequent ball trajectory in videos of an expert player performing table tennis serves. By using functional magnetic resonance imaging, the brain activity was evaluated in expert and nonexpert table tennis players during their predictions on the fate of the ball trajectory in congruent versus incongruent videos. Compared with novices, expert players showed greater activation in the sensorimotor areas (right precentral and postcentral gyri) in the comparison between incongruent vs. congruent videos. They also showed greater activation in areas related to semantic processing: the posterior inferior parietal lobe (angular gyrus), middle temporal gyrus, and ventromedial prefrontal cortex. These findings indicate that action anticipation in expert table tennis players engages both semantic and sensorimotor regions and suggests that skilled action observation in sports utilizes predictions both at motor-kinematic and conceptual levels.
•Involvement of the semantic network in skilled action anticipation was examined.•Table tennis expert and nonexpert players predicted congruent or incongruent action sequences.•Functional magnetic resonance imaging assessed brain activation during an action anticipation task.•Predicting domain-specific actions involves both semantic and sensorimotor networks in experts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The learning of the table tennis course is a practical course where the characteristics are unique so that mastery of basic techniques is highly dependent on doing more repetitions. The correct ...movement will appear along with the automation of the motion. The purpose of the research and development of this table tennis throwing device is to (1) develop a table tennis throwing tool for the process of implementing table tennis learning, (2) obtain empirical data about the feasibility of the table tennis throwing tool that has been developed. The ultimate goal of this development research is to produce a product in the form of learning media, namely a table tennis ejection tool that can provide meaningful movement experiences and can help improve basic technical skills to the ability to play table tennis. The method used Research and Development (R&D) methods from Borg and Gall. The research subjects are college students of Sports Education at Universitas Bina Darma. Instrument test used observation and questionnaires. Data analysis techniques were carried out with qualitative and quantitative approaches. This product is produced through the research and development stage. The resulting product is a table tennis ball. Based on the product trial analysis phase, the resulting product answers the needs and becomes a solution for lecturers and students in the implementation of table tennis course learning. Based on the results of validation tests, instrument reliability tests, small group try-out and field try group, this table tennis ejection tool is feasible and can be used in learning table tennis theory and practice courses.
This research is a research activity testing the effectiveness of table tennis digital teaching materials, which previously this product has gone through a development process (expert judgment, ...small-scale field tests and large-scale field tests). This study aims to obtain teaching material products that are effectively used by students in learning table tennis. The method used in this research is the experimental method. The subjects involved in this study were 30 experimental groups and 30 control groups. The subjects of this study were students who were taking table tennis courses at the Physical Health and Recreation Education Study Program, Medan State University. The data analysis technique used in this study is the feasibility percentage technique. Based on the results of data analysis, it can be described that the results of the research can be seen from the results of the pretest, the two groups have almost the same percentage of learning outcomes. where the experimental group's pretest results were 41.92% while the control group was 42.50% with a difference of 0.88%. Based on this percentage, it can be categorized that student learning outcomes in the cognitive aspect have not been completed. Furthermore, the results of the post-test of the two groups experienced an increase from the results of the pre-test, where the experimental group achieved a completeness percentage of 92.2% while the control group was 82.1%, this percentage can be categorized as complete classically, but in the post-test results the percentage of the experimental group was higher than with the percentage of the control group. Based on this research data, it can be concluded that the digital materials developed in this study are suitable for use by educators as teaching materials in table tennis lectures.
In all professional sports, performance pressure is high at the top level. Therefore, rules are defined and controlled to keep sports fair in accordance e.g. with the Agenda 21 of the International ...Olympic Committee. However, it’s about money and honour and as a consequence it is obvious that the athletes will go to the limits at all levels or even beyond. This is not only true for performance-enhancing substances to improve the physical capacity but – when sports equipment is involved – also for their optimisation. Thus, rules and related controls are necessary with regard to fairness between competitors but also with regard to their health when chemicals are involved. In table tennis, such chemicals (so-called boosters) are used occasionally – but against the rules – to improve the performance of the rackets. In the present study, several boosters were analysed as well as numerous common racket coverings using ion mobility spectrometry coupled to gas-chromatographic pre-separation. After optimisation of sampling with regard to improving reproducibility, characteristic patterns of volatiles for booster compounds and for racket coverings with different characteristics were developed successfully. In particular, signals related to particular softening agents could be identified and detected even in the untreated coverings. The patterns of volatiles were found to be characteristic for the particular boosters investigated as well as for the particular coverings. Furthermore, those patterns enable a differentiation between booster and covering or – in other words – between rule-consistent racket coverings and rule violation by after treatment of the rubber with a booster. After adaptation of the entire procedure to realistic competition situations, the method could be used for proving an infringement against the prohibition of applying such compounds.
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•Ion mobility coupled to gas chromatography (GC-IMS) enables booster control in table tennis.•Characteristic VOC patterns of table tennis coverings and from boosters can be differentiated.•Quantitative and selective determination of relevant compounds by calibration.•Short analysis time (1–2 min) using mobile GC-IMS allows booster monitoring on-site.•This analytical tool GC-IMS could help keeping sports fair and equitable.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aims to determine the effect of multiball training on forehand accuracy in table tennis extracurricular students. This research was conducted at SMA Negeri 7 Bengkulu City. In this study ...using a Quasi experimental method (quasi experimental). The design used was one group pretest posttest design, that is, pretest was done before treatment and posttest was done after treatment. The treatment given was multiball training with various variations. This design requires a group without comparison. The population in this study amounted to 16 students, the sample selection used a total sampling technique where the entire population was taken as the research sample. The data collection technique in this study was the direct test method, namely using the 1x pretest, 14x trials and 1x posttest in table tennis. The statistical prerequisite test fulfills the requirements that the data is normally distributed based on statistical counts. The results obtained from the data t count 142.13 and t table 2.13145 with a level of = 0.05. The results of this study indicate that there is an effect of multiball training on forehand accuracy in table tennis extracurricular students at SMA Negeri 7 Bengkulu City, so it can be concluded that multiball training affects the improvement of forehand accuracy in table tennis extracurricular students.
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