반복적인 손목 및 손가락 작업에서의 수작업 부하 평가

권오채,윤명환,Gwon, O-Chae,Yun, Myeong-Hwan 대한인간공학회 1999 大韓人間工學會誌 Vol.18 No.2

The purpose of this study was to evaluate the manual workload in repetitive wrist and finger motion. To evaluate manual workload, angular displacement of the joint, EMG of the muscle and subjective rating were studied. Both wrist motion and finger motion were studied. A screw-driving task was used for the wrist motion experiment. A keyboard typing task was used for the finger motion experiment. All finger joint angles and wrist angles were measured by an angle-measuring glove($CyberGlove^{TM}$, Virtual Technologies, Inc.). Surface EMG was recorded from FCU muscle and FDS muscle simultaneously with the angle measurement. Subjective ratings of exertion were also recorded using the modified Borg's CR-10 scale. Repetition rates of 0.5, 1, 2 motions per second were used with each task. As a result, manual workload increased with increasing repetitiveness. Peak spectral magnitude and frequency components corresponded closely with joint angular displacement amplitudes and repetition rates. Results of the correlation analysis showed that there were significant correlation among EMG, frequency-weighted motion and subjective measurement. Both EMG and frequency-weighted filtering showed consistent workload estimation with increasing task frequency. Subjective ratings showed slight over-estimation of the workload as the task frequency is increased.

손측정변수들 간의 연관성 분석을 통한 장갑설계의 중요변수 결정 및 치수체계 적용

권오채,정기효,선미선,유희천,김희은,Gwon, O-Chae,Jeong, Gi-Hyo,Seon, Mi-Seon,Yu, Hui-Cheon,Kim, Hui-Eun 대한인간공학회 2004 大韓人間工學會誌 Vol.23 No.3

Selection of a key dimension (s) by considering the characteristics of hand dimensions is needed to design gloves and construct a sound sizing system for gloves The present study identified key dimensions of glove design by analyzing the relationships between hand dimensions and demonstrated the construction process of a glove sizing system. By conducting correlation and regression analyses on 70 hand dimensions including 3 key dimension candidates (hand length; hand circumference; hand breadth) with the 1988 US Army data, hand length and hand circumference were selected as key dimensions for glove design. Glove sizing systems were constructed for males and females by applying the selected key dimensions, 0.5 inch of sizing intervals, and 2% of presence rate criterion to the US Army data. This study suggests that glove sizing systems for males and females be very different from each other and a glove sizing system for males include more sizes than that for females.

수작업의 반복성 평가 방법 비교 및 분석

권오채,선미선,유희천 대한산업공학회 2003 대한산업공학회 춘계학술대회논문집 Vol.2003 No.5

수작업의 반복성 평가 방법 조사

권오채,유희천,Gwon, O-Chae,Yu, Hui-Cheon 대한인간공학회 2003 大韓人間工學會誌 Vol.22 No.3

Evaluation of repetitiveness for hand-intensive tasks is essential to determine the level of risk for upper-extremity musculoskeletal disorders at the workplace. Many measures and methods have been introduced for repetitiveness assessment: however, our understanding of the differences among these measures and methods is lacking. The present study compared the repetitiveness measures and measurement/analysis methods to help practitioners apply the proper repetitiveness assessment methodology in the workplace. By reviewing 51 studies of repetitiveness assessment, measures and corresponding measurement/analysis methods were surveyed. Of the repetitiveness measures, two types of dimensions (frequency and time) and corresponding types of analysis scopes were identified. According to the dimensional and analysis-scope types. the repetitiveness measures were categorized and then the surveyed studies were counted for each measure. It is identified that frequency measures have used 2.7 times higher than time measures and the frequency of wrist motions has been most frequently used in repetitiveness assessment. Furthermore, the measurement methods were categorized into objective and subjective methods, and the analysis methods into statistical and spectral methods. Lastly, eight factors (accuracy, reliability. sensitivity. efficiency. ease of use. applicability. interference. and robustness) were listed to be considered in selecting the appropriate assessment methodology.

천장 크레인 운전 작업부하 평가모델 개발

권오채,이상기,조영석,박정철,정기효,유희천,한성호,Kwon, O-Chae,Lee, Sang-Ki,Cho, Young-Seok,Park, Jung-Chul,Jung, Ki-Hyo,You, Hee-Cheon,Han, Sung-H. 대한인간공학회 2007 大韓人間工學會誌 Vol.26 No.2

The operating tasks of overhead crane have caused undue stress to the operators from physical, mental, and environmental workload. Existing workload assessment models for musculoskeletal disorders such as OWAS, RULA, and QEC have limited applicability to the crane operating tasks because they focus mainly on physical factors and do not consider the relative importance of each factor. The present study was to develop a workload assessment model customized to overhead crane operation, following a systematic process: (1) analyzing task characteristics, (2) selecting workload factors, (3) developing assessment methods, (4) establishing action levels, and (5) computerizing the assessment model. Based on literature review, worksite survey, and focus group interview, 4 physical factors (awkward posture, static posture, repetitive motion, and excessive force), 6 mental factors (visual demand, auditory demand, task complexity and difficulty, time urgency, work schedule related stress, and safety related stress), and 4 environmental factors (noise, vibration, dust, and temperature) were selected and their rating scales and relative weights were determined. Then, based on the workload assessment results of 8 overhead cranes operated at different workplaces, the action levels of each factor category were established. Finally, the crane operation assessment model was computerized for effective analysis and report preparation. The present approach is applicable to develop a customized workload assessment model for an operating task under consideration.

2 차원 동적 모델을 이용한 키보드 기울기와 타이핑 속도의 인체역학적 평가

권오채,류태범,윤명환 대한산업공학회 1998 대한산업공학회 추계학술대회논문집 Vol.1998 No.10

장갑 설계 적용을 위한 손동작에 따른 손체표의 길이변화 분석

권오채,선미선,정기효,이민정,연수민,유희천,김희은,Kwon, O-Chae,Sun, Mee-Sun,Jung, Ki-Hyo,Lee, Min-Jeong,Yeon, Soo-Min,You, Hee-Cheon,Kim, Hee-Eun 대한인간공학회 2005 大韓人間工學會誌 Vol.24 No.4

A glove design which reflects the changes in hand surface by hand motion can reduce the undesirable effects of use of gloves on hand performance. The present study examined changes in hand length dimensions due to hand motion and identified significant factors affecting the length changes. Recruiting 120 males and females in their 20s and 30s having various hand lengths, this study measured 10 hand length dimensions, defined at 2 hand areas(phalangeal and metacarpal areas) for 5 digits, when the hand is stretched and in fist, and then calculated the percentage of length increase for each dimension. ANOVA and simple-effect analyses showed the length change percentages were mainly different depending on digit and hand area: 111-127% at the phalangeal area and 112-116% at the metacarpal area. The length change percentages of the index, middle, ring, and little fingers in the phalangeal area ascended in order and showed a high correlation(r = 0.94)with the ranges of motion of the fingers.

앉은 자세에서 힘 수준에 따른 상지관절 동작별 최대 수용 반복 빈도수 분석

권오채,유희천,정기효,Kwon, O-Chae,You, Hee-Cheon,Jung, Ki-Hyo 대한인간공학회 2005 大韓人間工學會誌 Vol.24 No.2

Evaluation of repetitiveness for upper extremity intensive tasks is essential to determine the level of risk for upper extremity musculoskeletal disorders at the workplace. However, experimental data available to establish the acceptable levels of repetitiveness for various postures and forces is lacking. The present study examined the maximum acceptable frequencies(MAFs; motions/min.) of shoulder, elbow, wrist, and index finger motions at different forces(1kgf and 4kgf for shoulder, elbow, and wrist; 0.25kgf and 1 kgf for index finger) in sitting. Seventeen right-handed males in 20s without having any history musculoskeletal disorders participated in the MAF experiment. The participants determined their MAFs for the upper extremity motions by using the self-adjustment method and their work pulse(increase in heart rate; beats/min.) and rating of perceived exertion(RPE) were measured when working at MAF. The MAFs of elbow, wrist, and index finger motions for each force level were about 2, 3, and 6 times the corresponding MAF(9 at the high force and 24 at the low force) of shoulder motion and the MAFs at the low force increased about 2 times those at the high force. The work pulses of elbow, wrist, and index finger motions for each force level were 70%, 50%, and 30% of the corresponding work pulse(17 at the high force and 12 at the low force) of shoulder motion and the work pulses at the low force were about 70 % of those at the high force. Lastly, the RPEs of the upper extremity regions were about level 3(moderate) or below.

수작업의 반복성 평가 척도 및 측정 방법 분석

권오채,선미선,유희천 대한인간공학회 2002 대한인간공학회 학술대회논문집 Vol.- No.-

반복성의 평가는 수작업으로 인해 발생 가능한 근골격계 질환의 위험정도를 분석하기 위한 중요한 부문이다. 본 연구에서는 수작업의 반복성 평가에 사용되어지는 평가 척도들과 측정 방법들을 분석하였다. 이를 위해, 기존 수작업의 반복성 연구에서 사용되어진 여러 가지 평가 척도와 측정 방법들을 조사하여 공통 요소들을 추출하였다. 결과적으로 반복성의 평가 척도들은 시간, 빈도수, 그리고 속도 측면에서 분석되었으며, 이에 따라 관련된 측정 방법들은 주관적 측정법과 객관적 측정법으로 분류되었다. 마지막으로 실험연구가 현장적용 시 반복성의 평가 척도 및 측정 방법들의 특성을 파악하기 위한 8개의 항목(정확성, 신뢰성, 민감성, 강건성, 간섭성, 효율성, 사용용이성, 적용범위)을 선정하였다.

손동작에 따른 손체표 길이 변화를 적용한 장갑 설계 평가

권오채,선미선,정기효,이민정,연수민,유희천,김희은,Kwon, O-Chae,Sun, Mee-Sun,Jung, Ki-Hyo,Lee, Min-Jeong,Yeon, Soo-Min,You, Hee-Cheon,Kim, Hee-Eun 대한인간공학회 2005 大韓人間工學會誌 Vol.24 No.4

Use of a glove made of materials with a low elasticity decreases the performance of the hand such as agility, dexterity, range of motion, and grip strength. The present study examined if the adverse effects of a low-elastic glove can be reduced by a design which accommodates the changes of hand surface lengths by hand motion. Two glove designs which provide patches of elastic cloth and pleats at the finger joints and knuckle were developed by considering the hand surface length changes, and then compared with two conditions(bare hand and conventional glove design that does not consider the dynamic characteristics of the hand dimensions) in terms of completion time in peg board insertion task, maximum grip strength, discomfort in hand motion, discomfort in force exertion, and overall discomfort by 24 right-handed participants. The test results confirmed that wearing of a glove significantly reduced the agility and grip strength capability of the hand and indicated that the novel designs were effective to lessen the performance decreases compared to the conventional design. Also, of the glove designs, the pleat glove design was found most preferred for both better hand performance and less subjective discomfort.