• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.834-839
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• 2004

In this paper, we investigate the optimal base position and joint configuration of a planar wheeled mobile manipulator in terms of manipulability measure. Taking into account the level of coordination between a manipulator and a platform, both local and global optimization problems are considered. First, based on the kinematic models of a mobile manipulator, the manipulability measures are expressed along with the analysis of the configurational dependency. Second, the geometric symmetry of a mobile manipulator in view of manipulability measure is analyzed, and for some base positions, the best and worst joint configurations are determined, Third, with reverence to the maximum, minimum, and average manipulability measures, the optimal base positions are determined, and the percent improvements due to the base relocation are discussed considering the relative scales among the platform size, the wheel radius, and the link length.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.15 no.2
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• pp.113-122
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• 1993

In recent years the relationship between occlusal stability, mandibular position and temporomandibular joint function has been greatly emphasized. Anterior repositiong splint has been used for the purpose of correcting a disk-condyle in coordination, so we have usually wed it in ease of the click of the temporpmandibular joint. We have used anterior repositioning splint in 28 patients who have chief-complain of click in symptoms of the temporomandibular joint arthrosis. At the patients who had long-lasting symptom and sign, late click or degenerative change of the temporomandibular joint, the anterior repositioning splint had less effect on than we had expected. So we are now to report that we must pay attention to use of anterior repositioning spint.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.39-50
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• 2016

Objective: The purposes of this study were to compare the kinematics of a two-arm kettlebell swing between experts and beginners and to identify the correct postures and biomechanical key points in an attempt to prevent sports injuries induced by a kettlebell swing. Methods: Four experts (height, $169.7{\pm}1.5cm$; weight, $70.5{\pm}1.8kg$; age, $32.0{\pm}1.0years$) licensed to teach kettlebell exercises and three beginners (height, $173.7{\pm}4.1cm$; weight, $78.3{\pm}3.8kg$; age, $30.0{\pm}1.4years$) with no kettlebell exercise experience participated in this study. Each participant performed 15 repetitions of a two-arm kettlebell swing using a 16-kg weight. Joint angles, angular velocities, and peak angular velocity sequences were calculated and compared between the two groups. Results: Large ranges of motion (ROM) of the pelvic angle and hip joints were detected in the experts, while beginners showed greater ROM of the shoulder joint. Peak angular velocity magnitudes and sequences were significantly different between the two groups. Experts lifted the kettlebell upward using the hip joints, pelvis, and shoulder joints (proximal to distal order) sequentially and lowered it using the reverse order of peak angular velocities from the shoulder to hip joints. Conclusion: Mobility of the pelvic segment and hip joint are required, while stability of the other joints is needed to produce appropriate two-arm kettlebell swings. The activation and coordination of the gluteal and hamstring muscles are key points in kettlebell exercises.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.147-153
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• 2016

The aims of this study were to evaluate the joint coordination between hip and knee joints in the transfemoral amputees, and its symmetry between sound and prosthetic limbs. Seven transfemoral amputees ($46.4{\pm}10.7-year-old$, $174.8{\pm}3.5cm$, $78.3{\pm}9.7kg$) and 7 able bodies ($24.0{\pm}4.5-year-old$, $174.5{\pm}5.9cm$, $66.9{\pm}9.4Kg$) participated in this study. They walked at a self-selected walking speed across a 10m level ground. Simultaneously angle and angular velocity in the hip and knee joint were measured by motion analysis system. Then continuos relative phase(CRP), standard deviations of CRP (CRP_SD) and symmetry index(SI) were calculated. In able bodies, there were no differences of the parameters between left and right limb(all p>0.05). However, significant differences between sound and prosthetic limb in most of the parameters, except for CRP for stance phase were shown (all p<0.05). There were differences in all SI between transfemoral amputees and able bodies (p<0.05). In conclusion, joint coordination was altered in transfemoral amputee during level walking and shown in interlimb asymmetry.

• Journal of muscle and joint health
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• v.18 no.1
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• pp.83-92
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• 2011

Purpose: The purpose of this study was to identify the changes of physical function, perceptual and cognitive function, emotional function, and functional independence in the institutionalized aged according to functional group activity program (self help Tai Chi exercise plus functional task). Methods: Study subjects were 20 institutionalized aged from June to October in 2010. The subjects received functional group activity program two times a week for 15 weeks. Physical function (grip strength, coordination, lower extremity strength, balance, gait, trunk flexibility), perceptual and cognitive function, emotional function(depression, social skill), and functional independence were measured before and after the program. Results: The subjects showed significantly increased physical function (coordination, lower extremity strength, gait, trunk flexibility), perceptual and cognitive function, emotional function (depression, social skill), and functional independence. The functional group activity program may be an effective strategy for institutionalized elders to enhance their functions. Conclusion: The functional group activity program may be effective on elderly institutions which have limitation in human, material, environmental resources.

• Journal of Oral Medicine and Pain
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• v.23 no.3
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• pp.281-288
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• 1998

The authors treated a 30-years old female patient who visited the Department of Oral Medicine, PNUH due to the chief complaint of limitation of mouth opening. The magnetic resonance imaging following clinical examination was used for establishing an accurate and reliable diagnosis and the patient was diagnosed as having anterior disc displacement without reduction in the right joint and anterior disc displacement with reduction in the left joint. For managing acute anterior disc displacement without reduction, mandible manipulation was applied first focusing on pain control and then stabilization appliance was used for maintenance of joint stabilization. With time, the sign and symptom was remarkably reduced and an active exercise program was recommended to maintain of normal muscle length, increase joint range of motion and develop normal coordination arthrokinematics. As a result of treatment, the patient did not complain discomfort of normal daily activities and it was difficult to consider that the displace disc was not reduced completely, but the improvement in range of motion and joint mobility were remarkably found. Therefore, an exercise program should be considered to maintain joint mobility and be effective as a self-care.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.23-27
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• 2009

The joint dispatch of regional electricity markets can improve the overall economic efficiency of interconnected markets by increasing the combined social welfare of the interconnected markets. This paper presents a new decentralized optimization technique based on Augmented Lagrangian Relaxation (ALR) to perform the joint dispatch of interconnected electricity markets. The Block Coordinate Descent (BCD) technique is applied to decompose the inseparable quadratic term of the augmented Lagrangian equation into individual market optimization problems. The Interior Point/Cutting Plane (IP/CP) method is used to update the Lagrangian multiplier in the decomposed market optimization problem. The numerical example is presented to validate the effectiveness of the proposed decentralized method.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.474-474
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• 2000

This paper shows that a system with two-link arm can obtain hand reaching movement to a target object projected on a visual sensor by reinforcement learning using a layered neural network. The reinforcement signal, which is an only signal from the environment, is given to the system only when the hand reaches the target object. The neural network computes two joint torques from visual sensory signals, joint angles, and joint angular velocities considering the urn dynamics. It is known that the trajectory of the voluntary movement o( human hand reaching is almost straight, and the hand velocity changes like bell-shape. Although there are some exceptions, the properties of the trajectories obtained by the reinforcement learning are somewhat similar to the experimental result of the human hand reaching movement.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.2
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• pp.161-170
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• 2014

PURPOSE: This study concerns the wheelchair-based rehabilitation of elderly people, investigating muscle activity and coordination of upper limbs during wheelchair-based new millennium health gymnastics with varying elbow exercise velocity. METHODS: Twelve elderly people participated in new millennium gymnastics twice per week during 12-weeks. The group was separated into 0.4, 1.0, and 1.6 Hz groups (controlled by the metronome speed). Range of motion was measured by electrogoniometer, electromyography signals used root mean square values. The data application was normalized using reference voluntary contraction (%RVC). Upper limb (wrist and elbow joint) data gathered while standing up after the "falling on hips" was investigated in terms of coordination of angle-angle plots. One-way ANOVA, paired t-test and Scheffe's post hoc comparisons, were used for statistical analyses. RESULTS: There were results taken before and after the experiments. The results demonstrated a significant improvement in the triceps brachii and flexor carpi radialis of the 0.4 Hz group (p<.05). There was significant difference in the triceps brachi of the 1 Hz group. No significant differences were found in all muscles of the 1.6 Hz group. Muscle co-activation indexes of the 0.4 Hz group were larger than the others. The 0.4 Hz graph was turning point synchronized clockwise. The 1 Hz graph was out of phase with the negative slope. The 1.6 Hz graph was turning point synchronized counterclockwise, and uncontrolled factor phase was offset on angle-angle plots. CONCLUSION: It is found that improvement of muscle activity and upper limbs coordination of elderly people using wheelchair-based new millennium gymnastics is optimal with elbow exercise velocity with a frequency of 0.4 Hz.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.204-209
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• 2004

This paper describes dynamic manipulability analysis of robotic arms moving in viscous fluid. The Manipulability is a functionality of manipulator system in a given configuration and under the limits of joint ability with respect to the tasks required to bt performed. To investigate the manipulability of underwater robotic arms, a modeling and analysis method are presented. The dynamic equation of motion of underwater manipulator is derived from the Lagrange - Euler equation considering with the hydraulic forces caused by added mass, buoyancy and hydraulic drag. The hydraulic drag term in the equation: is established as analytical form using Denavit - Hartenberg (D-H) link coordination of manipulator. Two analytical approaches based on Manipulability Ellipsoid are presented to visualize the manipulability of robotic arm moving in viscous fluid. The one is scaled ellipsoid which transforms the boundary of joint torque to acceleration boundary of end-effector by normalizing the torque in joint space while the other is shifted ellipsoid which depicts total acceleration boundary of end-effector by shifting the ellipsoid in work space. An analysis example of 2-link manipulator with proposed analysis scheme is presented to validate the method.