• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.561-568
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• 1994

A man model can be used as an effective tool to design ergonomically sound products and workplaces, and subsequently evaluate them properly. For a man model to be truly useful, it must be integrated with a posture prediction model which should be capable of representing the human arm reach posture in the context of equipments and workspaces. Since the human movement possesses redundant degrees of freedom, accurate representation or prediction of human movement was known to be a difficult problem. To solve this redundancy problem, a psychophysical cost function was suggested in this study which defines a cost value for each joint movement angle. The psychophysical cost function developed integrates the psychophysical discomfort of joints and the joint range availability concept which has been used for redundant arm manipulation in robotics to predict the arm reach posture. To properly predict an arm reach posture, an arm reach posture prediction model was then developed in which a posture configuration that provides the minimum total cost is chosen. The predictivity of the psychophysical cost function was compared with that of the biomechanical cost function which is based on the minimization of joint torque. Here, the human body is regarded as a two-dimensional multi-link system which consists of four links ; trunk, upper arm, lower arm and hand. Real reach postures were photographed from the subjects and were compared to the postures predicted by the model. Results showed that the postures predicted by the psychophysical cost function closely simulated human reach postures and the predictivity was more accurate than that by the biomechanical cost function.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.336-343
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• 2015

One of various main jobs in the design of a new tactical vehicle is to develop the lightest chassis parts satisfying the required durability target. In this study, the analytic methods to reduce the size and weight of a lower control arm and chassis frame of a Korean light tactical vehicle are presented. Topology optimization by ATOM (Abaqus Topology Optimization Module) is applied to find the optimal design of the suspension arm with volume and displacement constraints satisfied. In case of chassis frame, the light-weight optimization process associated with design sensitivity method is developed using Isight and ABAQUS. By these analytic methods we can provide design engineers with guides to where and how much the design changes should be made.

• Earthquakes and Structures
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• v.23 no.6
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• pp.535-547
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• 2022

Handball sport, as its name postulates, is a team sport which highly physical workout. During a handball play, several ball impacts are applied on the hands resulting vibration in the forearm, upper arm, shoulders and in general in whole body. Hand has important role in the handball's game. So, understanding about the dynamics and some issues that improve the stability of the hand is important in the sport engineering field. Ulna and radius are two parallel bones in lower arm of human hand which their ends are located in elbow and wrist joint. The type of the joint provides the capability of rotation of the lower arm. These two bones with their ends conditions in the joints constructs a 4-link frame. The ulna is slightly thinner than radius. So, understanding about hand kinematics in handball's game is an important thing in the engineering field. So, in the current work with the aid of a multi-physics simulation, dynamic stability analysis of the ulna and radius bones will be presented in detail.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.385-386
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• 2007

• Journal of information and communication convergence engineering
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• v.9 no.6
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• pp.743-746
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• 2011

An implementation for surface EMG network analysis and vertical control system of robotic arm is presented in this paper. The transmembranes are simulated by equivalent circuit and cable equation for propagation to be converted to circuit networks. The implementation is realized to be derived from the detecting EMG signal from 3 electrodes, and EMG transmembrane signals of human arm muscles are detected by several surface electrodes, high performance amplifier and filtering, converting analog to digital data and driving a servomotor for spontaneous robotic arm. The system is experimented by monitoring multiple steps vertical control angles corresponding to biceps muscle movement. The experimental results are that the vertical moving control level is measured to around 2 degrees and mean error ranges are lower 5%.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.62-69
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• 1996

Lateral arm flap has been used for the reconstruction of the various defects in hand, head and neck region. This flap is highly dependable as a free flap because of its thin flap thickness, constant vascular anatomy and possibility of osteocutaneous flap and fascial flap. Recently, many authors tried extended approach for vascular pedicle and distal flap extension for bigger defects. In this study, we review previous articles and 14 cases used lateral arm flaps for coverage of the varying defect on head and neck, upper and lower extremities succesfully. In conclusion, lateral arm flap has constant anatomical structure and can overcome the disadvantages such as short pedicle length and limited flap size, then the range of its application can be very widened.

• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.1-5
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• 2020

In this paper, a predictive maintenance of the robot trouble using the machine learning method, so called MT(Mahalanobis Taguchi), was studied. Especially, 'MD(Mahalanobis Distance)' was used to compare the robot arm motion difference between before the maintenance(bearing change) and after the maintenance. 6-axies vibration sensor was used to detect the vibration sensing during the motion of the robot arm. The results of the comparison, MD value of the arm motions of the after the maintenance(bearing change) was much lower and stable compared to MD value of the arm motions of the before the maintenance. MD value well distinguished the fine difference of the arm vibration of the robot. The superior performance of the MT method applied to the prediction of the robot trouble was verified by this experiments.

• International Journal of Safety
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• v.10 no.1
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• pp.32-35
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• 2011

Lifting capacity and difficulty of task are influenced by body posture. In RULA and REBA, the body was divided into segments which formed two groups, A and B. Group A includes the upper and lower arm and wrist while group B includes the neck, trunk and legs. This ensures that whole body posture is recorded so that any awkward or constrained posture of the legs, trunk or neck which might influence the posture of the upper limb. This study aimed to measure MVC (maximum voluntary contraction) and subjective judgment in psychophysical method (Borg's scale) according to trunk and upper arm angle and to analyze results statistically. The results of this study were that lifting capacity was more influenced by interaction of body posture rather than angles of each part, and MVC variation according to trunk and upper arms angles should different patterns. This means that we consider the interaction of trunk angles and upper arm angles when we access risk factors of the postures. This survey would be also the basic data to evaluate difficulty of lifting tasks according to body postures ergonomically.

• Korean Journal of Computational Design and Engineering
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• v.11 no.1
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• pp.49-56
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• 2006

In this study, the modeling support system was developed which can make easy and fast FE-modeling and verify the results of static and durability analysis for the lower arm, one of the important parts in automobile suspension module. It took into account of the whole complicated design processes verifying the durability coefficients evaluated by fatigue analysis, which should be used to satisfy a design criteria. To guide the FE-modeling the drive page was constructed by using HTML and XML, which was based on expert's know-hows. It is able to integrate the processes to design the lower arm in practice, so that the standardization of its FE-Modeling is achieved, consequently. The 3 dimensional CAD's geometrical data were changed automatically into pre-defined shell elements under the concept of mesh-offset technique, and then welding elements were treated to connect between target and basic surfaces constructed by the shell elements. This system has also a user interface to control boundary and load ing conditions applied in performing of the static and durability analysis, in which many load cases can be applied simply with the MPCs driven by just few mouse clicks. These were implemented on the platform of MSC.Patran and utilized ANSYS, MSC.Nastran and MSC.Fatigue as the solver of the analysis performed. The developed system brings not only significant decreasing of man-hours required in FE-modeling process, but also obtaining of satisfied qualities in analyzed results. It will be integrated in a part of virtual prototyping module of the developing e-engineering framework.

• Journal of the Korean Society of Costume
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• v.54 no.1
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• pp.69-81
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• 2004

The purpose of this study was to find out apparel fit satisfaction according to item(jacket, pants, skirt) by body perception and body satisfaction. This research was done by a survey method. Descriptive Statistics, Pearson's Correlation, Crosstabs were used for data analysis. The results of this study are as follows. 1) Correlation between body perception and body satisfaction : The subjects were less satisfied with larger or thicker girth of upper body. The subjects were less satisfied with thicker upper arm, lower arm, waist and lower abdomen. The subjects were more satisfied with taller height. The subjects were less satisfied with larger or thicker girth of lower body. The subjects were less satisfied with thicker hips. thighs, calves, ankles, and longer crotch length. However, they were more satisfied with longer legs. 2) Apparel fit by body perception and body satisfaction: The subjects who were less satisfied with thicker upper arm, waist, thighs and wider hips were less satisfied with the upper arm area, waist area. hip area of jacket. The subjects who were more satisfied with longer arms were more satisfied with the sleeve length of jacket. The subjects who were less satisfied with wider shoulder width were less satisfied with the upper back width of jacket. It means the shoulder width affected more the upper back width of jacket than shoulder width of jacket. The subjects who were less satisfied with wider hips were less satisfied with the hip area of pants and skirt. The subjects who were less satisfied with thicker thighs were less satisfied with the thigh area and the hip area of pants and skirt. The subjects who were less satisfied with longer crotch length were less satisfied with the crotch length of pants. 3) Difference between actual body and perceived body by Rohrer Index: Rohrer Index 109 calculated by average of the ideal height(165.83cm) and weight(49.78kg) of the subjects ranged in thin body type(below 120). The subjects tended to perceived their bodies fatter than their actual bodies. Also, the subjects tended to perceived their lower bodies fatter than upper bodies.