• Advances in Computational Design
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• 제1권4호
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• pp.315-327
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• 2016

Damage detection and localisation in structures is essential since it can be a means for preventive maintenance of those structures under service conditions. The use of structural modal data for detecting the damage is one of the most efficient methods. This paper presents comparative performance of various state-of-the-art meta-heuristics for use in structural damage detection based on changes in modal data. The metaheuristics include differential evolution (DE), artificial bee colony algorithm (ABC), real-code ant colony optimisation (ACOR), charged system search (ChSS), league championship algorithm (LCA), simulated annealing (SA), particle swarm optimisation (PSO), evolution strategies (ES), teaching-learning-based optimisation (TLBO), adaptive differential evolution (JADE), evolution strategy with covariance matrix adaptation (CMAES), success-history based adaptive differential evolution (SHADE) and SHADE with linear population size reduction (L-SHADE). Three truss structures are used to pose several test problems for structural damage detection. The meta-heuristics are then used to solve the test problems treated as optimisation problems. Comparative performance is carried out where the statistically best algorithms are identified.

• 한국운동역학회지
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• 제26권1호
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• pp.51-69
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• 2016

Objective: The purpose of this study is to suggest new terminology for the ninety-five hand techniques based on the significance of their angular momentum, determined by analyzing each technique's influence or impact on the compartmentalized angular momentum of the trunk, upper arm, and forearm in the Taekwondo Poomsae. Method: An athlete who won the 2014 World Taekwondo Poomsae championship was selected and agreed to participate in the data collection phase of our investigation. The video data was collected using eight infrared cameras (Oqus 300, Qualysis, Sweden) and the Qualisys Track Manager software (Qualisys, Sweden). The angular momentum of each movement was then calculated using the Matlab R2009a software (The Mathworks, Inc., USA). Results: The classification of the ninety-five hand techniques in the Taekwondo Poomsae based on the significance of each segment's momentum is as follows. Makgi (blocking) is classified into fourteen categories, jireugi (punching) is classified into three categories, chigi (hitting) was classified into six categories, palgupchigi (elbow hitting) was classified into four categories, and jjireugi (thrusting) was classified two categories. Conclusion: This study offers a new approach, based on a biomechanical method, to the classification of the hand techniques that reflect kinesthetic motions in the Taekwondo Poomsae.

• 한국운동역학회지
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• 제17권1호
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• pp.41-52
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• 2007

The present study analyzed the two hand backhand stroke motion of six female high school tennis players who won the championship at the National Athletic Meeting in 2006, and drew conclusions as follows. The open angle of the racket at the moment of impact was 90 degree without significant difference among the players, making a wide contact between the ball and the racket. The racket angle was 43 degree at take back and 91 at impact, showing a style of holding the racket rather upright in general. In back swing from the top to the impact, the shoulders and the hips turned by 97 degree and 40 degree, respectively. At the moment of impact, the height of the impact was 54%H, and the position of the impact was 10%H ahead of and 37%H left from the central axis of the body. The right hand made a continental grip and the left hand made a Western or semi Western grip. Through the entire swing motion, the grip angle of the left hand was smaller than that of the right hand, and those who maintained a large grip angle of the right hand at the moment of take back put the racket head slightly farther from the body. In the swing of the racket head from the lowest point to the impact, the vertical length of movement was 11%H and the horizontal length of movement was 60%H, quite long.

• 한국운동역학회지
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• 제15권3호
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• pp.133-142
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• 2005

The purpose of this study was to compare of the kinematic variables from takeoff preparation to takeoff used by long jumpers who recorded over 8meters in 2002 Busan Asian Game and 2003 Daegu Universiade and 2001 national championship. The kinematic characteristics from the last three stride to takeoff at the takeoff board were analyzed such as velocities, heights and angles. The conclusion were as follows; In order to record over 8meters the national long jumpers should have under 5cm height variation at the penultimate stride of the run-up. In the approach phase the horizontal velocity of the jumpers should reach to 10m/s in touchdown at takeoff board The vertical velocity must have 3.75m/s simultaneously in order to record 8meters. The jumpers need to continue talent of the horizontal velocity in touchdown at takeoff board and require jumping power of the takeoff leg at takeoff board The appropriate body variation range ratio between takeoff and touchdown should be 1.2 vs 1 and the trunk angle at touch down on the board should be close to the erect posture for higher body flight.

• 한국운동역학회지
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• 제20권4호
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• pp.457-467
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• 2010

This study intends to analyze the projection factors' difference on each record of women's javelin throwing. For this purpose, the research analyzed the best record and the lowest one of athletes in top 1~7 ranks respectively, who participated in 2009 Daegu Pre-Championship Meeting. For analyze kinematic factors, we analyzed their game photos mainly shot by 3 cameras installed in side places. The used analysis program was Kwon3D 3.1. Analysis variables were the projection velocity, angle, height, trunk lean angle, and supporting leg's knee angle. The results concluded as follows: Different record showed statistically significant differences(p<.05) in terms of horizontal velocity and resultant velocity. There were no statistically significant differences in the variables of projection angle, its height, trunk lean angle and knee angle of support leg. But for the analyzed results to each individual characteristics, the horizontal velocity, projection height, knee angle of support leg and trunk lean angle of release event appeared to have influence on record.

• 한국운동역학회지
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• 제28권2호
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• pp.79-85
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• 2018

Objective: This study aimed to create a strategic training method to enhance optimal athletic ability using information from 1H to 10H rhythmic units. Method: Top three world class athletes and three national winners of 110-m hurdle finals from the 2010 Daegu International Athletics Competition and 2017 National Athletics Championship, respectively, were selected. To analyze the kinematic variables, Dartfish 9.0 was used for two-dimensional analysis. Results: Regarding the interval time from the start to the finish line, the national athletes took less time during the pure acceleration phase (start to 1H) than the foreign athletes. The horizontal velocity increase was slower after 1H; the national athletes showed a lack of ability to accelerate at the interval phases. Moreover, the hurdle clearance time between phases was longer in the national athletes than in the foreign athletes and lacked consistency. Conclusion: The national athletes lacked the ability to accelerate at the transition, maximum rhythm, rhythm maintenance, and re-acceleration phases and showed a longer hurdle clearance time. If technical improvements and strategic training methods using rhythmic units are applied for hurdling motions, the national athlete's hurdling abilities, performance, and consistency could improve.

• 운동영양학회지
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• 제13권3호
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• pp.185-192
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• 2009

The aim of this study was to examine the use of such dietary supplementation practices, opinions, taking period for dietary supplement, and among elite Judoists varying in age and gender. Subjects were recruited from Korea National Team Judoists in elite athlete training centers (Taenuing in Seoul, Korea and surrounding area), a total of 223 elite Judoists (2003y n=34, 2005y n=41, 2006y n=101, 2007y n=30, 2008y n=17). Data were collected from personal interviews with Judoists who participated at the Olympic games, Asian game and World Championship game since 2003-2008. Elite Judoists representing mean age of 2003y (men: 23.5±2.7, women: 22.6±2.4), 2005y (men: 23.4±2.6, women: 22.5±2.3), 2006y (men: 20.3±3.2, women: 21.9±2.4), 2007y (men: 25.3±2.6, women: 22.5±2.8) and 2008y (men: 23.9±3.9) completed a validated questionnaire assessing dietary supplementation practices and opinions. Older Judoists were significantly more likely to report greater dietary supplementation usage; to be advised by oneself; health food store and pharmacy retailers; to decrease taking period days per week and past 6 month. Relative to gender, significant differences were observed for the types of dietary supplementation reported; supplementation practice trend; reasons for dietary supplementation use.

• Advances in nano research
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• 제15권4호
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• pp.329-337
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• 2023

Wearing the right sportswear is one of the essential points in exercising, which is mainly neglected. Sportswear should be suitable for the ambient temperature and not cause more heat or cold in the athlete's body. On the other hand, increased sweating and blood circulation during exercise should not cause fatigue or heatstroke in the athlete. Nanotechnology has grown significantly in the field of producing more efficient equipment in the field of sports. The increase in demand in sports for complete sports equipment has revealed the necessity of using the highest quality materials in this sector. In the world of championship sports, a minor change in equipment can lead to significant changes in causing failure and victory. Since the sole is the most critical part of sports shoes, with the introduction of nanotechnology and nanocomposites, it is possible to help athletes rush and increase their sense of calm and satisfaction. Using nanocomposites in the soles of shoes can improve some of their characteristics, prevent the smell and sweat of shoes, and induce water repellency in these shoes. In this research, titanium dioxide (TiO₂) nanocomposite, along with cellulose, has been used to create antibacterial and hydrophobic properties in the soles of sports shoes. The synthesized nanocomposite has been synthesized using the least amount of chemicals, which shows this method's easy and cost-effective synthesis.

• Steel and Composite Structures
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• 제51권4호
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• pp.417-440
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• 2024

Artificial neural networks (ANN) have been the focus of several studies when it comes to evaluating the pile's bearing capacity. Nonetheless, the principal drawbacks of employing this method are the sluggish rate of convergence and the constraints of ANN in locating global minima. The current work aimed to build four ANN-based prediction models enhanced with methods from the black hole algorithm (BHA), league championship algorithm (LCA), shuffled complex evolution (SCE), and symbiotic organisms search (SOS) to estimate the carrying capacity of piles in cold climates. To provide the crucial dataset required to build the model, fifty-eight concrete pile experiments were conducted. The pile geometrical properties, internal friction angle 𝛗 shaft, internal friction angle 𝛗 tip, pile length, pile area, and vertical effective stress were established as the network inputs, and the BHA, LCA, SCE, and SOS-based ANN models were set up to provide the pile bearing capacity as the output. Following a sensitivity analysis to determine the optimal BHA, LCA, SCE, and SOS parameters and a train and test procedure to determine the optimal network architecture or the number of hidden nodes, the best prediction approach was selected. The outcomes show a good agreement between the measured bearing capabilities and the pile bearing capacities forecasted by SCE-MLP. The testing dataset's respective mean square error and coefficient of determination, which are 0.91846 and 391.1539, indicate that using the SCE-MLP approach as a practical, efficient, and highly reliable technique to forecast the pile's bearing capacity is advantageous.

• 한국콘텐츠학회논문지
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• 제8권10호
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• pp.278-286
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• 2008

본 연구는 프로축구 관중의 라이프스타일이 관람유인요인에 미치는 영향을 규명하기 위하여 프로축구 관중의 라이프스타일이 충성도 및 관람유인요인에 미치는 영향을 규명하고자 하였다. 이러한 연구 목적을 달성하기 위하여 성남종합운동장에서 열린 2007 K-리그 챔피언 결정전 관중 500명을 대상으로 유층집락무선 표집법을 이용하여 표본을 추출하였다. 자료처리는 회수된 설문자료 중에서 기재 내용이 부족하거나 자료검색 과정에서 응답 내용의 신뢰성이 없다고 판단된 것은 분석에서 제외시키고 최종 486명의 자료를 SPSS Win. 12.0 프로그램을 이용하여 개별 통계 처리하였다. 구체적인 통계처리 방법은 조사대상의 일반적 특성을 알아보기 위하여 빈도분석을 실시하였고 라이프스타일, 관람유인요인의 영향을 알아보기 위하여 상관관계분석, 중다회귀분석을 실시하였다. 이상의 연구 방법과 절차를 통해 통하여 프로 축구 관중의 라이프스타일이 관람유인요인에 미치는 영향에 관하여 다음과 같은 결론을 도출하였다. 첫째, 프로축구 관중의 라이프스타일은 충성도(행동적, 태도적)에 영향을 미친다. 둘째, 프로축구 관중의 라이프스타일(레저활동형, 유행추구형, 신세대의식형, 출세지향형)은 관람유인요인(경기장요인, 경기상황요인, 관람비용요인, 관람촉진요인, 위락성요인, 선수요인)에 영향을 미친다.