휴대용 위상배열 초음파 레일 탐상 장치

이행섭,온진호,전승룡,임재천 한국철도학회 2019 철도저널 Vol.22 No.5

8호선 전동차 무인화 시스템 적용 방안에 관한 연구

이행섭(H. S. Lee),이희성(H. S. Lee) 한국도시철도학회 2014 한국도시철도학회논문집 Vol.2 No.2

The vehicle of Sub Line No.8 is running automatically based on ATC/ATO system. However, in spite of the choosing vehicle considered for driverless driving, the vehicle cannot drive without a man. So this paper covers considering the devices for driverless driving of Sub Line No. 8 and which interface is needed for the driverless driving for the vehicle(Sub Line No.8) to contribute secure use of driverless driving through the analyzing pros and cons of RF-CBTC driverless system of Shinbundang Line and Fixed Block system of Sub Line No.8

내림 경사로 보행 시 전족부 탈-부착형 아웃솔의 각도 및 형태 변화가 하지 근활성도에 미치는 영향

이행섭 ( Haeng-seob Lee ),정재후 ( Jae-hu Jung ),채원식 ( Woen-sik Chae ) 한국스포츠과학원 2017 체육과학연구 Vol.28 No.2

[Purpose] The purpose of this study was to evaluate the effect of detachable forefoot outsole on muscle activity of the lower extremity during downhill walking. [Methods] Thirteen male university students (age: 23.5±2.1 yrs, height: 175.7±4.6 cm, weight: 651.9±55.5 N) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked down 20° ramp with forefoot`s design for the detachable outsole`s angle(5°, 10° and 20°) and type(A and B). To assess the myoelectric activities of selected muscles, six of surface EMG(QEMG8, Laxtha Inc. korea, sampling frequency = 1,024 Hz, gain = 1,000, input impedance > 1012 Ω, CMRR > 100 dB) electrodes with on-site pre-amplification circuitry were attached to ES, RF, BF, TA, LG, and MG. For each dependent variable, two-way ANOVA with repeated measures was used to determine whether there were significant differences among forefoot`s design for the detachable outsole`s angle and type (p<.05). When correlation effect was not statistically significant, post hoc analyses were performed using the multiple comparison through bonferroni, and if correlation effect was statistically significant, one-way ANOVA was performed as for the form of outsole which is an inter-group variable in order to find out simple main effect, and the paired t-test was performed to find out the angle of outsole, which is an intra-group variable. [Results] In IDLS phase, In terms of Rectus Femoris, 10°-B outsole showed statistically higher muscle movement than 5°-B, 5°-A outsole showed statistically higher muscle movement than 5°-B, 20°-A outsole showed statistically higher muscle movement than 20°-B. Among these outsoles, [Conclusion] 5°-B outsole was found to the most useful outsole for improving stability and controlling the bodily movement due to the body weight load when walking down the ramp.

배드민턴 포핸드 헤어핀 동작 시 숙련 정도에 따른 손가락 압력 및 운동학적 변인 비교 분석

이행섭 ( Haeng Seob Lee ),채원식 ( Woen Sik Chae ),정재후 ( Jea Hu Jung ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.4

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±0.8 yrs, height: 176.8±1.5 cm, weight: 640.9±48.6 N) with minimum of 6 years of experience and eight recreational players (age: 27.9±1.6 yrs, height: 177.1±6.1 cm, weight: 820.5±62.8 N) 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.

고등학생의 성별에 따른 수직점프 유형별 운동역학적 분석

이행섭 ( Haeng Seob Lee ),주명덕 ( Myung Duck Ju ) 한국운동역학회 2006 한국운동역학회지 Vol.16 No.4

내리막 보행시 발 전족부 부착형 아웃솔의 각도 변화가 척추기립근과 하지근의 근활성도에 미치는 영향

이행섭 ( Haeng Seob Lee ),채원식 ( Woen Sik Chae ),정재후 ( Jea Hu Jung ),김동수 ( Dong Soo Kim ),임영태 ( Young Tae Lim ),장재익 ( Jea Ik Jang ) 한국운동역학회 2014 한국운동역학회지 Vol.24 No.2

The purpose of this study was to evaluate the effect of angle change of forefoot`s adhesive outsole on the electromyographic activity (EMG) of the erector spinae and selected lower limbs muscle during downhill walking over -20o ramp. Thirteen male university students (age: 25.4±3.9 yrs, height: 176.2±5.1 cm, weight: 717.4±105.0 N) who have no musculoskeletal disorder were recruited as the subjects. To assess the myoelectric activities of selected muscles, six of surface EMG electrodes with on-site preamplification circuitry were attached to erector spinae (ES), rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), lateral gastrocnemius (LG), and medial gastrocnemius (MG). To obtain maximum EMG levels of the selected muscles for normalization, five maximum effort isometric contraction were performed before the experimental trials. Each subject walked over 0o and 20o ramp with three different forefeet`s EVA outsole (0, 10, 20o) in random order at a speed of 1.2±0.1 m/s. For each trial being analyzed, five critical instants and four phases were identified from the recording. The results of this study showed that the average muscle activities of MG and LG decreased in 20o shoes compared to 0o and 10o ones in the initial double limb stance (IDLS). In initial single limb stance (ISLS) phase, the average muscle activities of ES increased with the angle of forefoot`s adhesive outsole, indicating that the increment of shoes` angle induce upper body to flex anteriorly in order to maintain balance of trunk. In terminal double limb stance (TDLS) phase, average muscle activities of TA significantly increased in 20o outsole compared to 0o and 10o ones. There was no external forces acting on the right foot other than the gravity during terminal single limb stance (TSLS) phase, all muscles maintained moderate levels of activity.

Rotation of Irregularly Shaped Liposome using Optical Tweezers

하청일,박혁규,이행섭 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.II

In recent years, optical tweezers have been used in various fields as attractive tools for trapping and manipulating small particles such as colloidal particles, bacteria, red blood cells, etc. However, most theories and experiments relating to optical tweezers mainly focus on the function of trapping and transferring objects spatially. In this work, we study the rotational motion of irregularly shaped biological material which is not birefringent, in terms of forming birefringence and optical torque.

내림 경사로 보행시 배낭 무게에 따른 하지 움직임의 운동역학적 분석

채원식 ( Woen Sik Chae ),이행섭 ( Haeng Seob Lee ),정재후 ( Jae Hu Jung ),김동수 ( Dong Soo Kim ) 한국운동역학회 2015 한국운동역학회지 Vol.25 No.2

Objective: The purpose of this study was to conduct biomechanical analysis of varying backpack loads on the lower limb movements during downhill walking over -20° ramp. Method: Thirteen male university students (age: 23.5±2.1 yrs, height: 175.7±4.6 cm, weight: 651.9±55.5 N) who have no musculoskeletal disorder were recruited as the subjects. Each subject walked over 20° ramp with four different backpack weights (0%, 10%, 20% and 30% of body weight) in random order at a speed of 1.0±0.1 m/s. Five digital camcorders and two force plates were used to obtain 3-d data and kinetics of the lower extremity. For each trial being analyzed, five critical instants were identified from the video recordings. Ground reaction force, loading rate, decay rate, and resultant joint moment of the ankle and the knee were determined by the inverse dynamics analysis. For each dependent variable, one-way ANOVA with repeated measures was used to determine whether there were significant differences among four different backpack weight conditions ( p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: The results of this study showed that the medio-lateral GRFs at RHC in 20% and 30% body weight were significantly greater than the corresponding value in 0% of body weight. A consistent increase in the vertical GRFs as backpack loads increased was observed. The valgus joint movement of the knee at RTO in 30% body weight was significantly greater than the corresponding values in 0% and 10% body weight. The increased valgus moment of 30% body weight observed in this phase was associated with decelerating and stabilizing effects on the knee joint. The results also showed that the extension and valgus joint moments of the knee were systematically affected by the backpack load during downhill walking. Conclusion: Since downhill walking while carrying heavy external loads in a backpack may lead to excessive knee joint moment, damage can occur to the joint structures such as joint capsule and ligaments. Therefore, excessive repetitions of downhill walking should be avoided if the lower extremity is subjected to abnormally high levels of load over an extended period of time.

윗몸일으키기 운동 시 싯업보드의 각도변화에 따른 근육활동 분석

박정호(JungHoPark),정재후(JaeHuJung),김동수(DongSooKim),이행섭(HaengSeobLee),채원식(WoenSikChae) 한국체육학회 2013 한국체육학회지 Vol.52 No.6

The purpose of this study was to investigate the effects of different sit-up bench angles on trunk and leg muscle activity. Eleven male students who did not have any musculoskeletal disorder related with one`s upper or lower limb were selected for subjects. To assess the myoelectrical activities of selected muscles, wireless and wired electromyograph devices were used. Average and peak nEMG levels of different muscles in different sit-up bench angles were determined for each participant. For each variable, a one-way of variance with repeated measures(p<.05) was used to determined whether there were significant differences among different sit-up bench angles. The results showed that all muscle activities except the erector spinae increased with increasing sit-up bench angle. In general, muscle activity recorded in the right side of trunk was greater than the corresponding value in the left one when sit-up bench angle increased. Since the subjects tend to sit up twisting their body rightwards at greater sit-up bench angles, it is possible that the initiation of the trunk flexion was mainly caused by the right side of trunk muscles. This study also found that muscle activity of the rectus femoris was significantly increased at 30° incline sit-up board. Since an increase in muscle activity of the rectus femoris may cause the pelvic malalignment, this phenomenon causes excessive stresses to the spine, which potentially increased injury in spinal columns. Therefore, this study suggested that sit-up workouts performed with 20° incline sit-up board or greater may not be suitable for ordinary people or patients. Additionally, it is considered that sit-up workouts on a highly inclined sit-up board is not suitable for bilaterally symmetric abdominal muscle training.

드롭 착지동작 시 마우스가드 착용이 운동역학적 변인에 미치는 영향

채원식 ( Woen Sik Chae ),이규복 ( Kyu Bok Lee ),정재광 ( Jae Kwang Jung ),이행섭 ( Haeng Seob Lee ),김동수 ( Dong Soo Kim ),정재후 ( Jae Hu Jung ) 한국운동역학회 2013 한국운동역학회지 Vol.23 No.4

The purpose of this study was to determine the biomechanical effect of wearing the mouthguard on the lower limb during drop landing. Nine male university students who have no musculoskeletal disorder were recruited as the subjects. Linear velocity, angular velocity, vertical GRF, loading rate, joint moment, and lower extremity muscle activity were determined for each subject. For each dependent variable, paired t-test was performed to test if significant difference existed between with mouthguard (WM) and without mouthguard (WOM) conditions (p<.05). The results showed that linear velocity, angular velocity, vertical GRF and loading rate were no significant difference between the two groups. The inversion moment of the ankle joint was increased in WM compared to WOM. Average IEMG values from BF, TA, and LG in WM were significantly greater than corresponding values in WOM during IP phase. This indicates that wearing mouthguard played a vital role in muscle tuning for maintaining joint stability of the lower limb and preventing injury.