• 한국안전학회지
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• 제27권6호
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• pp.185-191
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• 2012

Rear collisions to expressway work trucks result many casualties these days. But, currently, no special measure are being taken except deploying sign trucks behind the working trucks. In the U.S and Europe, trucks with TMA(Truck Mounted Attenuator) are being deployed behind the working truck, which is regarded as the standard method for work area safety, thereby reducing the fatality rates and property damage tremendously. Also, standard for the performance of TMA are established and TMA can be used in the field only when it satisfies the standard. In Korea, neither the standard for nor any guide to the TMA exists. In the situation some manufacturer developed TMA without proper performance evaluation and marketed limited number of TMAs in the field. In the study, NCHRP350, which is the performance standard of expressway safety features of U.S. and materials related to the TMA standard in Europe have been reviewed to establish the Korean performance criteria. Based on the review, and incorporating existing Korean standard for crash cushions, domestic standard for TMA has been proposed and applied in developing Korean TMA and crash tested it to verify the performance. The original design developed was crash tested and modified. The newly proposed design was studied using impact simulation program several times. Modifications were made after each simulation and prototype was built and crash tested as per the newly established TMA performance criteria.

• 한국정보통신학회논문지
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• 제13권3호
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• pp.505-513
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• 2009

Z. cao는 Relation matrix를 사용한 정밀한 추론이 가능한 NFRM(New fuzzy reasoning method)을 제안하였다. 이는 추론의 규칙 수가 적음에도 불구하고 Mamdani의 퍼지 추론방식에 비하여 좋은 성능을 보였다. 그러나 대부분의 퍼지스템의 경우, MIMO 시스템에 적용 시 퍼지 추론규칙을 도출해 내기 힘들고 많은 규칙의 수가 요구되는 단점을 갖는다. 그러므로 본 연구자에 의하여 과거에 Z. Cao's의 퍼지 추론방법을 MIMO 시스템으로 확장된 MIMO 퍼지추론 방식이 제안되었다. 그러나 정밀한 추론을 위하여 relation matrix는 휴리 스틱 (heuristic)한 방법이나 시행착오법을 사용하여 구하였고, 이는 많은 시간과 노력이 필요하다. 본 연구에서는 이러한 relation matrix를 구하기 위하여 시행 착오법에 의해 소요되는 많은 시간과 노력을 줄이고, 더욱 정밀한 추론 성능의 개선을 위하여 경사감소학습법을 사용한 학습기 능을 갖는 MIMO 퍼지추론 방식을 제안하고자 한다. 모의실험은 2축 로봇의 역기구학 문제를 푸는데 적용하여 제안된 추론방식이 좋은 성능을 보였다.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.104-113
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• 2013

New USNCAP has been carried out by NHTSA including front and side crash from MY2011. In this paper, test results for USNCAP Side crash were reviewed by statistical analysis. This review focused on side crash test results to investigate the effect of changes from new USNCAP side crash test protocol among 30 passenger cars. These results were summarized as followings. Total number of 5 star vehicles on the front seat dummy (16 vehicles, 53.3%) was slightly smaller than the rear seat's (17 vehicles, 56.7%) in MDB test. For the ES-2re dummy, chest injury, ie maximum rib deflection contributed to 66% in the mean value of $P_{joint}$. Pelvis injury was highly dependent upon performance up to 87% in the SID-IIs dummy cited on the rear seat in average $P_{joint}$. For Pole test, pelvis injury made contribution to the average performance to 83%. For standard deviation, it showed the largest value in the same body region as the mean value for each dummy. Overall front seat performance showed 14 vehicles, 44.6% with 5 star vehicles less than each MDB or Pole test result. This result showed that performances in MDB test were different pattern to Pole test on driver position. Number of 5star vehicles for overall side NCAP performance are 18 passenger cars (60%). Curtain airbag and driver thorax airbag were equipped in all test vehicles. One vehicle is equipped with thorax airbag in the rear seat. Results from two side tests considered as reliability problem, ie the cause for large standard deviation in side crash test. Consequently, the countermeasure for new USNCAP side crash test is essential to design the effective side structures for side collision and to control well dummy kinematics with curtain and thorax airbag in order to reduce chest and pelvis injuries.

• 한국운동역학회지
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• 제15권3호
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• pp.9-19
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• 2005

The purpose of this study was to analyze the effects of three different types of preparatory movement(squat, countermovement and hopping) in sideward responsive propulsion movement. 7 healthy subjects performed left and right side movement task by external output signal. 3D kinematics were analyzed The results were followed First, performance time in the countermovement and hopping conditions was shorter(10-20%) than that in the squat condition. The hopping condition that is more related to pre-stretch showed excellent performance. Second, time difference between after turned on the external signal and until take off was the primary factor in performance results among movement conditions. The preparatory phase before the propulsive phase in the squat condition produced more time than that in other conditions. The hopping condition showed the most short time in both the preparatory and the propulsive phase, therefore it was advantage for performance result Third, significant difference was not found in take-off velocity among movement conditions although there was difference of the time required in the propulsive phase. The maximum acceleration in the propulsive phase was larger in order of the hopping. countermovement, and squat condition. The countermovement and hopping conditions showed high take-off velocity although the propulsive phase in those conditions was shorter than that in squat condition. The pre-stretch by preparatory countermovement was considered as the positive factor of producing power in concentric contraction. Fourth, the hopping condition produced large angular velocity of joints. In hopping condition, large amount of moment for rotation movement was revealed in relatively short time and it was considered to cause powerful joint movements. In conclusion, the hopping movement using countermovement is advantage of responsive propulsion movement. It is resulted from short duration until take off and large amount of joint moment and joint power in concentric contraction by pre-stretch.

• 한국운동역학회지
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• 제13권2호
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• pp.89-100
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• 2003

In this research was to analyze 3-D kinematics variables for handspring of basic motion in the heavy gymnastics in order to investigate kinematical difference between expert and novice. Therefore, the purpose of this research was provide quantitative information, systematic provision, rules, establishment of basic skill for improving skill and teaching athletes. And in the research, results were as followings. 1. In the time variables, total time was that expert took 0.745sec and novice took 0.829sec, and as duration time of each event, expert was faster than novice in the all motion event except till second event of the preparation motion. 2. In the center of body variables, vertical direction variables, the displacement of body center hight was that expert showed 61.26% and novice showed 54.48% in the third event of all motion, also all event were showed expert was higher displacement than novice except first of event in preparatory stage. 3. In the angle displacement of main joint, the right direction was that expert showed 154.12degree and novice showed 174.85degree and the left direction was that expert showed 159.29degree and novice showed 171.46degree In the second event of main joint curved point at the same time hand was reached floor. In the angle displacement of knee joint in the third event of all motion, expert showed 155.25degree and novice showed 154.00degree In right, and expert showed 155.24degree and novice showed 154.55degree in left. In this result, both were same motion type. In the angle displacement of hip joint in the third event of the all motion, expert showed 142.80degree and novice showed 134.17degree in right, and expert showed 140.28degree and novice showed 144.94degree in left. In this result, motion pattern of expert was same both sides, but novice was different. According to the results, to increase efficiency of motion and aesthetic effect in the all motion, it should stretch displacement and height of body center and make similarly angle of right and left joint.

• 한국운동역학회지
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• 제22권4호
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• pp.387-394
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• 2012

The purpose of this study was to compare and analyze the finger pressure and kinematic variables in the forehand hairpin net shot between skilled elite players and less skilled recreational players. Eight elite players(age: $18.1{\pm}0.8yrs$, height: $176.8{\pm}1.5cm$, weight: $640.9{\pm}48.6N$) with minimum of 6 years of experience and eight recreational players(age: $27.9{\pm}1.6yrs$, height: $177.1{\pm}6.1cm$, weight: $820.5{\pm}62.8N$) with less than one year experience were recruited in this study. For each trial being analyzed, four critical instants were identified from the video recordings: Right heel contact1 (E1), Right toe-off (E2), Right heel contact2 (E3), and Shuttlecock Impact (E4). Each hairpin net shot was broken into consecutive phases: E1~E2 (Right Landing Phase: RLP), E2~E3 (Sliding Step Phase: SSP), and E3~E4 (Impact Phase: IP). Temporal parameters, shuttlecock speed, linear and angular kinematics of body segments, and finger pressures were computed for this study. The results showed that The finger pressure of the ring finger and the middle finger for the skilled group during an impact had significantly greater than those of unskilled group. It is possible that all fingers were not used in the same manner when the racket was gripped in forehand hairpin. The result also suggested that the ring finger and the middle finger pushed the racket from top to bottom while having the mid-phalanx and proximal phalanx of index finger as an axis.

• 한국운동역학회지
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• 제20권4호
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• pp.437-445
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• 2010

This study was aimed at comparing selected joint angles at the golf address stance by categorizing three different body types. 43 elite male golfers were selected and 9 of them turned out to be the ectoderm while 24 of them to be the mesoderm. The remaining 10 subjects were the endoderm. The measurement was carried out at the address stance with the number 7 iron and the driver. The result showed that the angle of trunk flexion did not different among body types. The trunk tilting angle became more inclined to the right side, which confirmed the guidelines from most of golf lesson books, for bigger people since they tended to put more weight on the right foot. The angle of both knees showed similar but the right knee was bent more than the left knee. The target direction and body alignment faced more to the left side than the target spot because of the influence of open stance and natural aiming position. It seems that pelvis and knees turned a little bit more to the right side than the target direction in order to maintain the parallel. Overall, significant differences among body types were found at the trunk tilting angle and pelvis-target alignment and golf address configuration can be differentiate by these factors.

• 한국운동역학회지
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• 제24권2호
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• pp.121-129
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• 2014

The purpose of this study was to investigate the effect of the toe headings on the biomechanics of knee joint in drop landing in an attempt to find the potential risk of non-contact anterior cruciate ligament (ACL) injury. Seventeen male college students ($20.5{\pm}1.1$ yrs; $175.2{\pm}6.4$ cm; $68.8{\pm}5.8$ kg), having no neuromuscular injury within an year, participated in this study. Three different toe headings such as toe-in (TI), neutral (N), and toe-out (TO) positions were tested. Motion capturing system consisting of eight high speed cameras and two force platforms were used to collect three-dimensional motion data and ground reaction force data during landing. Results indicated joint angles and peak joint moments were significantly affected by the toe headings. TI position produced larger valgus angle due to reduce knee distance in addition to higher flexion and valgus moment than other positions, which was somewhat vulnerable to the potential risk of non-contact ACL injury. TO position caused the largest internal rotation angle with smaller joint moments. Therefore, it is recommended that athletes need to land on the ground with neutral toe-heading position as possible in order to minimize the potential risk of non-contact ACL injury.

• 한국운동역학회지
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• 제24권4호
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• pp.435-443
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• 2014

The purposes of this study was to investigate the physical compensation for gait on induced equinus in normal subjects. Ten subjects were participate in the experiment (age: $23.8{\pm}2.8yrs$, height: $177.3{\pm}4.3cm$, weight: $70.8{\pm}4.6kg$). The study method adopted 3D analysis with six cameras and ground reaction force with two force-plate. Induced equinus were classify as gait pattern on unilateral and bilateral equinus. The results were as follows; In displacement of COM, medio-lateral and anterior-posterior COM were no significant, but in vertical COM, unilateral equinus gait was higher than bilateral equinus gait. In displacement hip joint, left hip joint was more extended in FC1 and FC2 during unilateral equinus gait. In displacement knee joint, left knee joint was more extended in FC2, right knee joint was more extended in all event during unilateral equinus gait. In trunk tilt, unilateral equinus gait was more forward tilt in TO1 and TO2. ROM of each joint was no significant. In Displacement of pelvic tilt angle, X axis of unilateral equinus gait was more increase than bilateral equinus gait at FC2, TO2 and MS2. Y axis of unilateral equinus gait was more increase than bilateral equinus gait at MS1, FC2 and MS2. Z axis was no significant in both equinus gait. In GRF, right Fx and Fy were no significant in both equinus gait, Fz was more bigger vertical force in bilateral equinus gait. Left Fx was more bigger internal force in unilateral equinus gait, Fy and Fz were no significant in both equinus gait.

• 한국운동역학회지
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• 제18권3호
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• pp.11-21
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• 2008

본 연구는 태권도 겨루기 경기에서 많이 사용되고 있는 받아차기 종류 중에서 반달차기 동작을 운동학적 변인과 근전도적 변인들에 대하여 카메라와 근전도 시스템 기법을 통해 분석하여 규명함으로써 태권도 겨루기 선수들과 지도자들에게 경기력 향상을 위하여 보다 효율적인 반달차기 수행능력을 제시함을 연구목적으로 하며 운동학적 및 근전도를 분석한 연구 결과는 다음과 같다. 태권도 겨루기 경기에서 반달차기는 발을 차는 다리의 슬관절 각 변위 변화가 상대를 임팩트 하는 순간 대단히 중요한 요인이 되며, 고관절 각변위는 발을 차는 다리와 상체 젖히기 각변위 변화는 매우 중요한 요인이다. 또한 근전도 변인들 중에서 반달차기 동작 수행 시에 차는 발의 반대쪽에 위치한 왼쪽부분의 척추기립근 근육들이 높은 근활동에 기여되고 있어 경기력 향상을 위한 효율적인 반달차기 수행능력을 위해서는 왼쪽부분에 위치한 척추기립근 근육들의 강화 훈련이 필요하다고 할 수 있으며, 체간운동에 따른 오른발반달차기 동작 시 오른쪽 부분에 위치한 복근이 높은 근활동에 기여함으로서 효과적인 반달차기 수행능력을 발휘 할 수 있을 것이다.