• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.49-58
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• 2009

This study aims to analyze the association between the center of mass(C.O.G) and ocular movement(E.O.G) according to the success and failure in the left turn motion on the balance beam, targeting three female gymnasts. When successful, the left-right C.O.G was moved to the left, which was a rotational direction until such time as the body rotated $180^{\circ}$, whereas there appeared to be a greater movement during failure; thus, it was shown to affect the maintenance of dynamic postural control. In case of the subsequent left-right turning motion of E.O.G, this matches the previous theory that the eyeball moves against the direction of rotation of the body. However, there was a difference at the time of movement, and a clear difference emerged in the success and failure in this study. Also, in the E.O.G in the up-down direction, a movement during failure showed a pattern of down direction in most cases; thus, it is deemed to affect the failure. Therefore, the kinetic postural control and E.O.G are supposed to affect the success and failure in a landing, which is the most importantly evaluated movement on the balance beam, in mutual association.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.493-498
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• 2004

A novel approach for path planning of a polygonal robot is presented. Traditional path planners perform extensive geometric searching to find the optimal path or to prove that there is no solution. The computation required to prove that there is no solution is equivalent to exhaustive search of the motion space, which is typically very expensive. Humans seems to use a set of several different path planning strategies to analyse the situation of the obstacles in the environment, and quickly recognize whether the path-planning problem is easy to solve, hard to solve or has no solution. This human path-planning strategies have motivated the development of the presented algorithm that combines qualitative shape reasoning and exhaustive geometric searching to speed up the path planning process. It has three planning stages consisting of identification of no-solution cases based on an enclosure test, a qualitative reasoning stage, and finally a complete search algorithm in case the previous two stages cannot determine of the existence of a solution path.

• Physical Therapy Korea
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• v.17 no.3
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• pp.11-19
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• 2010

The purpose of the study was to determine the effects of balance training with 'TETRAX' system, a balance training and assessment tool, on balance and mobility in acute hemiplegic patients. Nineteen matched subjects were assigned randomly into either an experimental group or a control group. An experimental group with 10 subjects received balance training with 'TETRAX' exercise program and conventional physical therapy interventions 5 times per week during 4 weeks. A control group with 9 subjects received conventional physical therapy interventions 5 times per week during 4 weeks. Outcome measures were taken before and after 4 weeks of interventions using the Stroke Rehabilitation Assessment of Movement (STREAM), the Berg Balance Scale (BBS), gait speed, and the fall down index. Results indicated that both exercise groups improved significantly in STREAM, BBS, and gait speed (p<.05). The experimental group had a little improvement than the control group. Both exercise groups did not show statistical significance in fall down index (p<.05). Following 4 weeks of intervention, except gait speed there was no statistically significant difference between two groups. However, these findings suggest that conventional physical therapy interventions with visual feedback training could be effective on improving balance and mobility than conventional physical therapy alone in acute hemiplegic patients.

• PNF and Movement
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• v.20 no.1
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• pp.41-49
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• 2022

Purpose: The aim of this study was to examine the effects of vibration exercise on balance control ability, gait ability, and depression in the elderly. Methods: A total of 24 elderly subjects were recruited and randomized into an experimental (n = 12) or a control (n = 12) group. The experimental group performed both a vibration and a stabilization exercise, and the control group performed a stabilization exercise alone. Balance ability was measured using the functional reach test (FRT), gait ability was measured using the timed up and go test (TUGT), and depression was measured using the Center for Epidemiologic Studies Depression Scale (CES-D). Results: The experimental and control groups showed significant differences for all pre- and post-experiment FRT, TUGT, and CES-D measurements (p <0.05). In a comparison between the two groups, the experimental group in which vibration exercise was applied showed more significant difference in FRT, TUGT, and CES-D than the control group (p <0.05). Conclusion: This study showed vibration exercise to be effective in balance control ability, gait ability, and depression in the elderly.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.89-89
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• 2017

해양경찰 소형 경비정에 주로 장착되었던 물분사(water jet type) propeller가 중대형 경비함으로 점차 확대되고 있으며, 축 형식은 2~4축, 유동을 제어하는 bucket 유형도 DRB, CSU(SRB) 방식으로 나뉘어져 있다. 그러나, W/Jet 추진기 고유의 운동 특성이 반영된 조함법의 연구가 부족한 편이다. 여기서는 함정에 장착된 W/Jet 유형별 SHS를 통하여 직접 구현해 보고, SHS 구현이 현실적으로 어려운 함정은 해양경찰 함정장들의 면담을 통하여 습득한 것을 이론적으로 구현 제시하여, 함정 조함시 지식적인 인적오류를 최소화하여 W/jet 추진기가 장착된 함정 승조원의 조함 능력 향상 및 안전운항에 기여하고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.33-43
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• 2001

The design and construction of special purpose vessels such as drillship and shuttle tankers have been increased. These vessels install the DPS(dynamic positioning systems) to maintain the position and heading for long-time operation. This paper deals with the experimental method for model-based DP system and the control theory and filter algorithms. In this experiment, the length of model ship is 4 meters and it has three thrusters to maintain the position. The ability of tracking along the given course and keeping of heading in waves are confirmed. For the calculation of thruster input the PID control theory are adopted and the effects of PID gain were investigated. To estimate the low frequency motions Kalman filter and digital filter were used and their effects were investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.139-146
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• 2023

Maritime object detection systems, which detects small maritime obstacles such as fish farm buoys and visualizes distance and direction, is equipped with a 3-axis gimbal to compensate for errors caused by hull motion, but there is a limit to distance error corrections necessitated by the vertical movement of the camera and the maritime object due to wave motions. Therefore, in this study, the distance error of maritime object detection systems caused by the movement of the water surface according to the external environment is analyzed and corrected using average filter and moving average filter. Random numbers following a Gaussian standard normal distribution were added to or subtracted from the image coordinates to reproduce the rise or fall of the buoy under irregular waves. The distance calculated according to the change of image coordinates, the predicted distance through the average filter and the moving average filter, and the actual distance measured by laser distance meter were compared. In phases 1 and 2, the error rate increased to a maximum of 98.5% due to the changes of image coordinates due to irregular waves, but the error rate decreased to 16.3% with the moving average filter. This error correction capability was better than with the average filter, but there was a limit due to failure to respond to the distance change. Therefore, it is considered that use of the moving average filter to correct the distance error of the maritime object detection system will enhance responses to the real-time distance change and greatly improve the error rate.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.69-77
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• 1991

A collision-free trajectory planning algorithm using an iterative learning concept is proposed for dual robot arms in a 3-D common workspace to accurately follow their specified paths with constant velocities. Specifically, a collision-free trajectory minimizing the trajectory error is obtained first by employing the linear programming technique. Then the total operating time is iteratively adjusted based on the maximum trajectory error of the previous iteration so that the collision-free trajectory has no deviation from the specified path and also that the operating time is near-minimal. To show the validity of the proposed algorithm, a numerical example is presented based on two planar robots.

• Science of Emotion and Sensibility
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• v.8 no.1
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• pp.37-45
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• 2005

This paper reports the remedial effect measurement of an obesity remedy machine for home use which has been developed by H Co. and the authors. It is expected that the machine enhances it's remedial effect and usability by utilizing medium frequency and thermotherapy belt etc. In order to measure it's remedial effect, a clinical experiment, which participates eight young female subjects, has been conducted for one month. The experiment includes the measurements on the changes of Gas-Exchange Responses of subjects through Cardio-Pulmonary Exercise Testing. The experimental results show that the obesity remedy machine helps the subjects to reduce their weights, fat rates, and $VCO_2s$. Thus, it turns out that the machine can be a good candidate for medical treatment on the obesity.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.245-255
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• 2009

The purpose of this study is to analyzed the coordination of lower limb of elderly women who experienced a fall to present basic information for sports science and to deal with the factors that make elderly women fall more effectively. Twenty elderly women were divided into two groups of 10. The mechanisms of balancing lower limb during walk and differences were compared and analyzed using motion analysis and electromyography. The findings of this study are as follows. The first, walking patterns of these women were unstable as their hip joints did not provide sufficient support because of aging. Second, the left and right knee joints showed different walking patterns. The third, the motions of ankle joints became abnormal with increased age. As for the activation of major lower limb muscles, rectus fermois muscle and biceps fermois muscle contracted more to prevent the bending of knees and moved forward while anterior tibial muscle and inner gastrocnemius muscle were demanded highly during walk and the rate of plantar flexion was reduced.