• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.463-470
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• 1999

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effect of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• 한국운동역학회지
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• 제24권3호
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• pp.209-216
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• 2014

The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.549-551
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• 1998

This paper deals with the new gait implementation of biped walking robot(IWR-III). In the case of using old gait. The trunk should be stopped during the phase changing time. But using new gait, the trunk moves continuously for all walking time. As a result, IWR-III has a walking gait similar to human being, and the motion of balancing joints can be reduced by the trunk ahead effect in the double support phase, moreover, ZMP tracking is improved, therefore the stability of IWR-III is improved. The trajectory is planned with a 5th order spline interpolation and stability of IWR-III is certified with a biped simulator.

• 디지털융복합연구
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• 제15권6호
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• pp.457-466
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• 2017

본 연구는 비만여성들의 모션비트 리듬운동의 실효성을 극대화하고 생활체육 현장에 적용을 기대하고자하며 지속적인 운동건강관리의 조성방안을 제시하는데 그 목적이 있다. 비만여성들에게 8주간 모션비트와 리듬운동을 융복합하여 건강증진행위의 변화를 분석하고자 하였으며 결과는 다음과 같다. 비만여성들의 8주간 주 3회 모션비트 리듬운동 적용에 따른 건강증진행위의 변화에서는 스트레스관리 요인에서 모션비트 적용이 효과가 나타나는 결과를 도출하였다. 8주간 주 3회 리듬운동 프로그램과 모션비트의 융복합된 중재효과를 통해 건강증진행위에 직접적인 영향에 기여하였으며, 비만인들의 모션비트를 적용한 운동 관리는 스트레스 대처에 긍정적인 수용과 자신감을 확보할 수 있었다. 아울러 모션비트를 적용한 운동은 재미와 흥미를 극대화시켜줌으로서 비만여성들을 위해 적절하고 효율적인 생활체육 프로그램으로 활용할 수 있으며, 지속적인 운동 참가의 조성방안으로 제시될 수 있다.

• 대한안전경영과학회지
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• 제24권3호
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• pp.47-53
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• 2022

In order to conduct a study on the importance of the wrist joint, which causes a lot of pain among middle-aged people, in relation to work related to musculoskeletal disorders, the effect of stretching on grasping power was studied. In order to compare the grasping power of the wrist for middle-aged people in their 50s, the experiment was conducted by comparing before and after the wrist joint motion stretching. According to the experimental results of wrist gripping power for the control group and the experiment group on wrist gripping power, it was investigated that stretching did not change much in increasing wrist gripping power, but stretching application had an effect on wrist gripping power. In terms of preventing musculoskeletal accidents, reducing pain due to degenerative diseases, and preventing accidents, stretching seems to have an effect when approaching, so it is considered that continuous stretching before and after work is necessary. Therefore, it is suggested that stretching time secured quantitatively through safety and health education before work is necessary.

• Structural Engineering and Mechanics
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• 제46권2호
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• pp.179-196
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• 2013

An experimentally measured single footfall trace (SFT) from a walking subject needs to be extended into a continuous force curve, which can then be used as load for floor vibration serviceability assessment, or on which further analysis like discrete Fourier transform can be conducted. This paper investigates the accuracy, applicability and parametrical sensitivity of four extension methods, Methods I to IV, which extends the SFT into a continuous time history by the walking step rate, stride time, double support proportion and the double support time, respectively. Performance of the four methods was assessed by comparing their results with the experimentally obtained reference footfall traces in the time and frequency domain, and by comparing the vibrational response of a concrete slab subjected to the extended traces to that of reference traces. The effect of the extension parameter on each method was also explored through parametrical analysis. This study finds that, in general, Method I and II perform better than Method III and IV, and all of the four methods are sensitive to their extension parameter. When reliable information of walking rate or gait period is available in the test, Methods I or II is a better choice. Otherwise, Method III, with the suggested extension parameter of double support time proportion, is recommended.

• Structural Engineering and Mechanics
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• 제43권5호
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• pp.679-690
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• 2012

A new concept sea-floating port called mobile harbor has been introduced, in order to resolve the limitation of current above-ground port facilities against the continuous growth of worldwide marine transportation. One of important subjects in the design of a mobile harbor is to secure the dynamic stability against wave-induced excitation, because a relatively large-scale heavy crane system installed at the top of mobile harbor should load/unload containers at sea under the sea state up to level 3. In this context, this paper addresses a two-step sequential analytical-numerical method for analyzing the structural dynamic response of the mobile harbor crane system to the wave-induced rolling excitation. The rigid ship motion of mobile harbor by wave is analytically solved, and the flexible dynamic response of the crane system by the rigid ship motion is analyzed by the finite element method. The hydrodynamic effect between sea water and mobile harbor is reflected by means of the added moment of inertia.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.18-23
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• 2012

The purpose of this study is to visually confirm on variation of temperature changes according to the basic of Kumdo by using infrared rays camera and to obtain the difference of temperature distribution according to the warm up procedure. We selected randomly two Kumdo players, and recorded twice continuously their actions of three basic(Head Hitting, Wrist Hitting, Waist Hitting) motions of Kumdo. In other to obtain the effect of warm up procedure, we recorded again their actions including warm-up motions. Four measuring points on the body were selected in each motion considering the error on continuous recoding. Temperature distributions of the before and after warming up procedure were analyzed at two measuring point. Skin temperature distributions of the players's body in two cases are shown a similar tendency. It can be predicted that the parts of large physical movement result in the large changes of temperature according to the warm up motion.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.31-37
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• 2012

The purpose of this study is to visually confirm on variation of temperature changes according to the basic of Taekgyoen by using infrared rays camera and to obtain difference of temperature distribution according to the warm up procedure. We selected randomly two Taekgyeon players, and recorded twice continuously their actions of three basic motions of Taekgyeon. In other to obtain effect of warm up procedure, we recorded again their actions including warm-up motions. Four measuring points on the body were selected in each motion considering the error on continuous recoding. Temperature distributions of the before and after warming up procedure were analyzed at two measuring point. Temperature distributions of skin of players body in two cases are shown a similar tendency. It can be predicted that the parts of large physical movement result in the large changes of temperature according to the warm up motion.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.384-388
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• 2007

Aerodynamic characteristics of Coleoptera species of Epilachna quadricollis and Allomyrina dichotoma are experimentally and numerically investigated. Using digital high speed camera and smoke wire technique, we visualized the continuous wing kinematics and the flight motion of free-flying coleoptera. The experimental visualization shows that the elytra flapped concurrently with the main wing both in the downstroke and upstroke motions. The wing motion of Epilachna quadricollis was captured and analyzed frame by frame to identify the kinematics of the wings and to implement it in the movement of a model wing (thin plate) in the simulation. The two-dimensional simulation of Epilachna quadricollis hovering flight was performed by assuming the wing cross section shape as a thin plate, even though most of insect's wings are made of curved corrugated membrane. The effect of Reynolds number are investigated by the simulation. Meanwhile, in order to investigate the role and effect of elytra, the flow visualization of Allomyrina dichotoma was carried on using smoke wire visualization technique. Here, we confirmed that the vortex generated by elytra due to its movement is strongly influence the vortex dynamic generated by hind wings.