• 대한산업공학회지
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• 제23권1호
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• pp.147-162
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• 1997

When designing workplaces or arranging controls on panel, devices and controls should be placed within the reach of operator's arm or foot to guarantee effective performances. Most of the existing research on the reach volume were based on measurements of a few subject's arm reach, and limited to Caucasian and Chinese populations. Furthermore, reach volume considering foot or trunk motion have not been investigated. Range of human joint motion and that of two degrees of freedom motion are needed to generate reach volume analytically using the sweeping algorithm. However, range of two degrees of freedom motion has not been measured up to now. Therefore, range of two degrees of freedom motion was measured in this research, where 47 college students were participated voluntarily as subjects. The results showed that the motion of one joint can be limited by the motion of another motion, that is to say, the shoulder flexion was decreased significantly when the shoulder was adducted or abducted. Second, new approximate algorithms generating reach volumes were suggested, in which range of two degrees of freedom motion was used as input data. Depending upon the body segment included such as trunk, arm and leg, three types of reach volume were provided, in which the human body was modeled as a multilink system based on the robot kinematics and the sweeping method was employed. Reach volume generated analytically in this study showed statistically reasonable results when compared with that obtained from direct measurement.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1996년도 추계학술대회논문집
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• pp.232-237
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• 1996

When designing workplaces or arranging controls on panel, devices and controls should be placed within the reach of operator's arm or foot to guarantee effective performances. Most of the existing research on the reach volume were based on measurements of a few subject's arm reach, and limited to Caucasian and Chineses populations, and foot reach and trunk motion have been excluded. Range of human joint motion and that of two degrees of freedom motion are needed to generate reach volume analytically using the sweeping algorithm. Therefore, in this research, range of two degrees of reedom motion was measured, in which 47 college students were participated volumtarily as subjects. Second, new approximate algorithms generating reach volumes were suggested based on the robot kinematics, in which range of two degrees of freedom motion was considered. Our analytically generated reach volume showed statistically reasonable results when compared with that obtained from direct measurement.

• 한국CDE학회논문집
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• 제16권4호
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• pp.249-259
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• 2011

In this paper we present our work on the parameterized construction of virtual drivers' reach motion to seat belt, by using motion capture data. A user can generate a new reach motion by controlling a number of parameters. We approach the problem by using multiple sets of example reach motions and learning the relation between the labeling parameters and the motion data. The work is composed of three tasks. First, we construct a motion database using multiple sets of labeled motion clips obtained by using a motion capture device. This involves removing the redundancy of each motion clip by using PCA (Principal Component Analysis), and establishing temporal correspondence among different motion clips by automatic segmentation and piecewise time warping of each clip. Next, we compute motion blending functions by learning the relation between labeling parameters (age, hip base point (HBP), and height) and the motion parameters as represented by a set of PC coefficients. During runtime, on-line motion synthesis is accomplished by evaluating the motion blending function from the user-supplied control parameters.

• 대한인간공학회지
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• 제29권1호
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• pp.73-82
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• 2010

The purpose of this study is to understand motion characteristics of older drivers during reaching seat belt compared to young drivers and to provide design guidelines in order to reduce discomfort for the elderly. The whole body kinematics of each subject was captured using 12-camera motion analysis system. Subjective ratings on discomfort levels were obtained simultaneously using a questionnaire. This paper first presents the result of motion characteristics of elderly drivers' reach motion to seat belt. Compared to young drivers, older drivers performed seat belt reach motions less efficiently and moved slower due to mostly the movement error. Older drivers also made use of reduced joint range of motion in cervical left rotation, lumbar left rotation and right shoulder adduction, which can be explained by their reduced active range of motions (AROMs). To compensate for their reduced joint range of motion, older drivers rotated pelvis more.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.22.1-22.10
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• 2020

Objectives: This study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files. Materials and Methods: A total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy. Results: The TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion. Conclusions: No significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.85-89
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• 1997

We used a three-dimensional motion capture method to measure the grasping reach of Korean. This method was applied well to the grasping reach measurement with low measurement error and high efficiency. We measured the grasping reach of 29 males and 21 females at the different height from seat reference level; -10, 0, 30, 60, and 90cm. The grasping reach data were summarized at each 15 .deg. in polar corrdinates to compare with the former researches. If the number of subjects increases in the supplement research, the grasping reach data will be used in the ergonomic design of the driver's cabin or workstations in industry.

• 대한산업공학회지
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• 제25권3호
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• pp.393-403
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• 1999

In this research, a reach posture prediction based on a two-segment trunk model was made. Recently, reach posture prediction models have used inverse kinematics to provide a single posture that a person naturally takes, with a single segment trunk model that had some shortcomings. A two-segment trunk model was first developed with two links; pelvis link and lumbar-thoracic link. The former refers to the link from the hip joint to L5/S1 joint while the latter does the link from L5/S1 to the shoulder joint. Second, a reach prediction model was developed using the two-segment trunk model. As a result, more reliable equations for two-segment trunk motion were obtained, and the lean direction which refers to the movement direction of the trunk was not found to have a significant effect on the two-segment trunk motion. The results also showed that the hip joint is more preferred over L5/S1 to serve as a reference point for trunk models and the reach prediction model being developed predicted the real posture accurately.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
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• pp.592-601
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• 1992

Reach posture의 정확한 예측은 인간모형이 구현되어 있는 CAD시스템에서 인간공학적 평가를 하는데 있어서 중요한 역할을 한다. 인간 골격구조의 복잡성과 그 행위의 특성에 대한 연구의 부족으로 인해 연구성과가 미미한 어려운 분야라 하겠다. 본 연구에서는 인간을 로보트와 같은 Multi-link system으로 간주하고, 로보트 Kinematics를 적용하여 Reach posture를 예측하고자 한다. 상지는 Hip, 어깨, 팔꿈치와 손목관절로 구성된 8자유도의 Redundant manipulator가 되고, 하지는 Hip, 무릎과 발목관절의 6자유도 link system이 된다. 상지의 Reach posture는 Resolved motion method를 이용하고, 하지는 Pieper's method를 사용하여 예측한다. 상지에 대한 Reach posture예측결과를 인간이 실제로 취하는 자세를 Motion Analysis system으로 검증해 본 결과 유사한 결과를 보였다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.787-796
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• 1995

A man model is a useful design tool for the evaluation of man machine systems and products. An arm reach trajectory prediction for such a model will be specifically useful to present human activities and, consequently, could increase the accuracy and reality of the evaluation. In this study, a three-dimensional reach trajectory prediction model was developed using an inverse kinematics technique. The upper body was modeled as a four link open kinematic chain with seven degrees of freedom. The Resolved Motion Method used for the robot kinematics problem was used to predict the joint movements. The cost function of the perceived discomfort developed using the central composite design was also used as a performance function. This model predicts the posture by moving the joints to minimize the discomfort on the constraint of the end effector velocity directed to a target point. The results of the pairwise t-test showed that all the joint coordinates except the shoulder joint's showed statistically no differences at .alpha. = 0.01. The reach trajectory prediction model developed in this study was found to accurately simulate human arm reach trajectory and the model will help understand the human arm reach movement.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 춘계학술대회논문집
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• pp.18-26
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• 1993

When designing workplaces, controls should be placed within the reach of operator's arm or foot to guarantee effective performance. The aviation industry is perhaps the chief user of anthropometric data for its need to weight minimization and space optimization. In designing a workplace which must cater to a wide range of operator size, it might be sufficient to plan only for the 'average person'. Static arm reach measurements which are taken in conventional, standardized positions provide the necessary information, but they cannot be directly applied to dynamic situations. In this research, an approximate algorithm to generate the workspace of the human body including foot reach and trunk motion is proposed and tested. The robot kinematics was employed to represent the human body as a multi-link system.