Extraction and Evaluation of Kinematic Feature Values of Batting Motion from Top of Swing to Ball Impact

2021 ◽  
Vol 141 (3) ◽  
pp. 258-263
Author(s):  
Hiroyuki Sogo ◽  
Tomohiro Henmi ◽  
Kousei Yoshizawa ◽  
Gou Saziki ◽  
Yuma Iwai ◽  
...  
Keyword(s):  
Ball Impact ◽  
Kinematic Feature ◽  
Feature Values

scholarly journals EXPERIMENTAL DISCUSSION ABOUT THE INFLUENCE OF THE PROFICIENCY IN TANKENDO IN THE FOOT POSTURE

2019 ◽  
Vol 7 (5) ◽  
pp. 296-305 ◽  
Author(s):  
Maki Nakamura ◽  
Kiyoshi Hoshino
Keyword(s):  
Negative Correlation ◽  
The Body ◽  
Years Of Experience ◽  
Strong Negative Correlation ◽  
Martial Art ◽  
Jump Distance ◽  
Foot Posture ◽  
Kinematic Feature ◽  
Feature Values ◽  
The Right

Purpose: In martial-art plays using a weapon, the length and weight of the used weapon determine the timing of attacking the opponent and playing strategies, which may be in turn reflected on the body posture and foot posture of a player. The objective of this study is to analyze the features of the food posture of a skilled player in Tankendo, in which players play using a short and light bamboo knife-like sword in order to consider an effective playing strategy. Methodology: In our experiment, the subjects were asked to take the foot posture at the temporal and spatial timing kept to measure and quantify kinematic feature quantities, weight distribution between both the feet placed in the front and rear, respectively and favorite jump distance of them. Then, a one-to-one correlation analysis was conducted among all the feature values. Main Findings: The result of the analysis demonstrated that a strong negative correlation was observed between the number of years of experience in Tankendo and the favorite jump distance. Similarly, a strong negative correlation was observed between the number of years of experience in Jukendo and favorite jump distance. On the other hand, in the case of Kendo, a strong negative correlation was observed between the number of years of experience in Kendo and the width between the feet placed on the right and left sides.     Implications/Applications: A series of results obtained from the study suggests that in Tankendo and Jukendo, players have such a tendency that they first would take a position near the opponent and then jump there up to strike the opponent. In contrast, in case of Kendo focusing on a thrusting technique, such a tendency was observed that with a narrow width between both the feet, players stroke their opponent so that speedy footwork might be achieved, despite easily losing body balance.

SMART IDENTIFICATION OF POWER QUALITY EVENTS USING NEW STOCKWELL TRANSFORM AND MACHINE LEARNING ALGORITHM

2019 ◽  
Vol XVI (4) ◽  
pp. 95-113
Author(s):  
Muhammad Tariq ◽  
Tahir Mehmood
Keyword(s):  
Machine Learning ◽  
Power Quality ◽  
Learning Algorithm ◽  
Machine Learning Algorithm ◽  
Noisy Environments ◽  
Satisfactory Performance ◽  
Feature Values ◽  
Learning Machine ◽  
Stockwell Transform ◽  
Electrical Utilities

Accurate detection, classification and mitigation of power quality (PQ) distortive events are of utmost importance for electrical utilities and corporations. An integrated mechanism is proposed in this paper for the identification of PQ distortive events. The proposed features are extracted from the waveforms of the distortive events using modified form of Stockwell’s transform. The categories of the distortive events were determined based on these feature values by applying extreme learning machine as an intelligent classifier. The proposed methodology was tested under the influence of both the noisy and noiseless environments on a database of seven thousand five hundred simulated waveforms of distortive events which classify fifteen types of PQ events such as impulses, interruptions, sags and swells, notches, oscillatory transients, harmonics, and flickering as single stage events with their possible integrations. The results of the analysis indicated satisfactory performance of the proposed method in terms of accuracy in classifying the events in addition to its reduced sensitivity under various noisy environments.

scholarly journals Ball Impact Position in Recreational Male Padel Players: Implications for Training and Injury Management

2021 ◽  
Vol 18 (2) ◽  
pp. 435
Author(s):  
Bernardino Javier Sánchez-Alcaraz ◽  
Rafael Martínez-Gallego ◽  
Salvador Llana ◽  
Goran Vučković ◽  
Diego Muñoz ◽  
...  
Keyword(s):  
Motion Tracking ◽  
Center Of Gravity ◽  
Musculoskeletal Injuries ◽  
Ball Impact ◽  
Video System ◽  
Injury Management ◽  
Racket Sports ◽  
Impact Position ◽  
Proper Training

Racket sports such as padel are characterized by the repetition of unilateral gestures, which can lead to negative adaptations like asymmetries or overuse musculoskeletal injuries. The purpose of this study was to determine the differences in ball impact positions (i.e., forward or backward of the center of gravity) in nine stroke types in a sample of forty-eight recreational male padel players. The sample included 14,478 shots corresponding to 18 matches from six tournaments. Forty-eight male padel players were classified into two groups according to their level: trained (n = 24) and novice (n = 24). Type of stroke and ball impact position were registered using a computerized motion tracking video system. The ball impact position was computed from the distance (cm) between the coordinates of the ball and the player’s center of gravity. Results show that trained players hit the ball in a more backward position (from 11 to 25 cm, compared to novice) in serve and offensive strokes (volleys, trays, and smashes) but used more forward strokes (from 7 to 32 cm, compared to novice) in defensive shots (groundstrokes, wall strokes, and lobs). Because the current differential variables are trainable and demonstrated to be of relevance for performance, the findings of this study may assist padel coaches in designing proper training plans to improve effectiveness and to prevent musculoskeletal injuries regarding the type of stroke and ball impact position. Such knowledge may constitute a very important factor affecting technique, biomechanics, and injury management in padel players of different competitive levels.

scholarly journals Impact cratering in sand: comparing solid and liquid intruders

Soft Matter ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 120-125
Author(s):  
Rianne de Jong ◽  
Song-Chuan Zhao ◽  
Diana Garcia-Gonzalez ◽  
Gijs Verduijn ◽  
Devaraj van der Meer
Keyword(s):  
Impact Cratering ◽  
Ball Impact ◽  
Solid Ball ◽  
Impact Energies

Crater characteristics are compared for droplet and solid ball impact on a granular target at the same effective impact energies.

scholarly journals Robustness of radiomic features in CT images with different slice thickness, comparing liver tumour and muscle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lorena Escudero Sanchez ◽  
Leonardo Rundo ◽  
Andrew B. Gill ◽  
Matthew Hoare ◽  
Eva Mendes Serrao ◽  
...  
Keyword(s):  
Large Fraction ◽  
Therapy Response ◽  
Response Assessment ◽  
Ct Images ◽  
Optimal Number ◽  
Image Features ◽  
Liver Tumour ◽  
Slice Thickness ◽  
Invasive Method ◽  
Feature Values

AbstractRadiomic image features are becoming a promising non-invasive method to obtain quantitative measurements for tumour classification and therapy response assessment in oncological research. However, despite its increasingly established application, there is a need for standardisation criteria and further validation of feature robustness with respect to imaging acquisition parameters. In this paper, the robustness of radiomic features extracted from computed tomography (CT) images is evaluated for liver tumour and muscle, comparing the values of the features in images reconstructed with two different slice thicknesses of 2.0 mm and 5.0 mm. Novel approaches are presented to address the intrinsic dependencies of texture radiomic features, choosing the optimal number of grey levels and correcting for the dependency on volume. With the optimal values and corrections, feature values are compared across thicknesses to identify reproducible features. Normalisation using muscle regions is also described as an alternative approach. With either method, a large fraction of features (75–90%) was found to be highly robust (< 25% difference). The analyses were performed on a homogeneous CT dataset of 43 patients with hepatocellular carcinoma, and consistent results were obtained for both tumour and muscle tissue. Finally, recommended guidelines are included for radiomic studies using variable slice thickness.

HUMAN FACE RECOGNITION FROM A SINGLE FRONT VIEW

1992 ◽  
Vol 06 (04) ◽  
pp. 571-593 ◽  
Author(s):  
CHING-WEN CHEN ◽  
CHUNG-LIN HUANG
Keyword(s):  
Face Recognition ◽  
Active Contour Model ◽  
Facial Feature ◽  
Recognition System ◽  
Facial Features ◽  
Human Face Recognition ◽  
Front View ◽  
Deformable Template ◽  
Face Recognition System ◽  
Feature Values

This paper presents a face recognition system which can identify the unknown identity effectively using the front-view facial features. In front-view facial feature extractions, we can capture the contours of eyes and mouth by the deformable template model because of their analytically describable shapes. However, the shapes of eyebrows, nostrils and face are difficult to model using a deformable template. We extract them by using the active contour model (snake). After the contours of all facial features have been captured, we calculate effective feature values from these extracted contours and construct databases for unknown identities classification. In the database generation phase, 12 models are photographed, and feature vectors are calculated for each portrait. In the identification phase if any one of these 12 persons has his picture taken again, the system can recognize his identity.

Ball Impact Dynamics of Instep Soccer Kicking

2009 ◽  
Vol 41 (4) ◽  
pp. 889-897 ◽  
Author(s):  
HIRONARI SHINKAI ◽  
HIROYUKI NUNOME ◽  
MASANORI ISOKAWA ◽  
YASUO IKEGAMI
Keyword(s):  
Impact Dynamics ◽  
Ball Impact
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