• Journal of the Korean Society of Physical Medicine
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• v.9 no.2
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• pp.223-231
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• 2014

PURPOSE: The aim of this study was to investigate the effect of closed and open kinetic exercises on knee extensor strength and balance in patients with early stroke. METHODS: Thirty patients with early stroke participated in the study. Participants were randomly assigned to three groups: an open kinetic chain (OKC) exercise group (n=10), a closed kinetic chain (CKC) exercise group (n=10), and a control group (n=10). All participants received conventional physical therapy for 30 minutes. In addition, the two experimental groups (OKC and CKC) participated in a 30-minute knee strengthening training program. Training for the experimental groups was carried out three times a week for four weeks. Outcomes such as knee extensor strength and balance ability (Tetrax, Functional Reaching Test, Timed Up and Go Test) were measured before and after training. RESULTS: There were significant differences in knee extensor strength and balance ability between the pre- and post-treatment of all groups (p<.05). The improvement of knee extensor strength was significantly higher in the OKC group than in the other groups (p<.05), and the improvement of dynamic balance was significantly higher in the CKC group than in the other groups (p<.05). CONCLUSION: These results showed that both open and closed kinetic chain exercises are effective in the improvement of knee extensor strength and balance ability. This study suggests that open and closed kinetic exercise training is an effective training for strength and balance in patients with early stroke.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.6
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• pp.105-111
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• 1995

The inverse dynamic equations for 5 link robot including a closed chain have been derived. The closed chain is virtually cut open, and the kinematics and dynamics of the virtual open chain robot are analyzed. The constraints are applied to the virtually cut joints by the Jacobian matrix which represents the configuration of the closed chain. The topology of tree structrued open chain robot is described by a FATHER array. The FATHER array of a link indicates the link tha tis connected in the direction of base link. Based on the inverse dynamic equations, the torque sensitivity models of the 5 link robot have been developed. The sensitivity models characterize the sensitivity of the driving torque with respect to the link parameters. All the procedures are illustrated through the 2 link robot.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.29-37
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• 2017

This papers focuses on remanufacturing processes in a closed loop supply chain. The remanufacturing processes is considered as one of the effective strategies for enterprises' sustainability. For this reason, a lot of companies have attempted to apply remanufacturing related methods to their manufacturing processes. While many research studies focused on the return rate for remanufacturing parts as a control parameter, the relationship with demand certainties has been studied less comparatively. This paper considers a closed loop supply chain environment with remanufacturing processes, where highly fluctuating demands are embedded. While other research studies capture uncertainties using probability theories, highly fluctuating demands are modeled using a fuzzy logic based ambiguity based modeling framework. The previous studies on the remanufacturing have been limited in solving the actual supply chain management situation and issues by analyzing the various situations and variables constituting the supply chain model in a linear relationship. In order to overcome these limitations, this papers considers that the relationship between price and demand is nonlinear. In order to interpret the relationship between demand and price, a new price elasticity of demand is modeled using a fuzzy based nonlinear function and analyzed. This papers contributes to setup and to provide an effective price strategy reflecting highly demand uncertainties in the closed loop supply chain management with remanufacturing processes. Also, this papers present various procedures and analytical methods for constructing accurate parameter and membership functions that deal with extended uncertainty through fuzzy logic system based modeling rather than existing probability distribution based uncertainty modeling.

• Journal of the Korean Society of Physical Medicine
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• v.3 no.1
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• pp.11-20
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• 2008

Purpose : This study was to comparison of EMG of an stable exercise group and unstable exercise group on patients who have had anterior cruciate ligament reconstruction(ACL reconstruction). Methods : The subjects of the study were patients who had no less than 4 weeks after ACL reconstruction and could stand on one leg, and they divided into a control group with 9 patients doing closed kinetic chain exercises on the stable floor and an experimental group with 10 patients doing closed kinetic chain exercises on the unstable floor and in order to compare degrees of the muscle activity of the thigh extensor and flexor was tested each before the exercise, in 3 weeks and 6 weeks after doing exercises by using surface electromyography (Surface EMG). The patients made 3 sets of exercises (10 times per set), each of which consisted of exercises using elastic bands and the squat. Results : There was statistic significance about the vastus medialis muscle. Conclusion : It is thought that the closed-chain exercise could be an exercise program through which patients could enhance the muscle activity of the vastus medialis muscle optionally among the quadriceps muscle and the hamstring muscles which should weaken after ACL reconstruction.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1023-1032
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• 1995

The multiple cooperating robot system plays an important role in the research of modern manufacturing system as the emphasis of production automation is more on the side of flexibility than before. While the kinematic and dynamic analysis of a single robot is performed as an open-loop chain, the dynamic formulation of robot in a multiple cooperating robot system differs from that of a single robot when the multiple cooperating robots form a closed kinematic chain holding an object simultaneously. The object may be any type from a rigid body to a multi-joint linkage. The mobility of the system depends on the kinematic configuration of the closed kinematic chain formed by robots and object, which also decides the number of independent input parameters. Since the mobility is not the same as the number of robot joints, proper constraint condition is sought. The constraints may be such that : the number of active robot joints is kept the same as mobility, all robot joints are active and have interrelations between each joint forces/torques, two robots have master-slave relation, or so on. The dynamic formulation of system is obtained. The formulation is based on recursive dual-number screw-calculus Newton-Eulerian approach which has been used for single robot analysis. This new scheme is recursive and compact symbolically and may facilitate the consideration of the object in real time.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.11 no.1
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• pp.7-12
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• 2013

Purpose : The purpose of this study was to identify effects of virtual reality-based closed kinetic chain (CKC) exercise on lower extremity muscle activity in chronic stroke patients Methods : Subjects were assigned randomly either to VR+CKC exercise group (n=15) or the CKC exercise group (n=15). When the study began, both groups received conventional physical therapy five times per week. The VR+CKC exercise group received virtual reality programs and the CKC exercise group received close kinetic chain exercises. Each exercise program was performed for six weeks (5 times per weeks; 20 minutes per time). Participants were measured on lower extremity muscle activity using EMG. Results : There was a significant increase of muscle activity (%RVC) in vastus lateralis and vastus medialis. Conclusion : In this study, the virtual reality-based closed kinetic chain exercise program was an effective exercise for improving lower extremity muscle activity in chronic stroke patients.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.201-203
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• 2022

Increasing global market of used electric vehicle (EV) battery encourages international firms to establish its subsidiary companies or business units specializing in battery recycling. Such kind of companies predominantly use closed loop supply chain (CLSC) for their operations of battery manufacturing and used battery recycling/reusing in global scale. However, EV battery recycling, as a relatively new industry, makes its global CLSC be exposed to various types of risks, which leads to inefficiency of supply processes and makes supply chains more complicated and vulnerable. Identifying, evaluating, and analyzing possible risks in CLSC has a great importance for optimization and increasing effectiveness for the global supply chain of used EV battery. Itwill assist to elaborate the efficient CLSC management and possible risk mitigation strategies to keep the global EV battery supply chain resilient and sustainable. This study aims to develop a conceptual framework for risk assessment in this new sector. Therefore, it will populate the framework with possible failure modes identified from various literature on EV battery recycling and closed loop supply chains so that future research can validate and utilize the conceptual framework.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.485-492
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• 2014

PURPOSE: This study aimed to examine the pain, range of motion (ROM), upper extremity task performance, and functional levels of patients after rotator cuff repair according to the timing of a closed chain exercise thereby presenting basic data for an effective rehabilitation program. METHODS: The intervention was applied three times per week, one hour per day, for four weeks to 40 participants, 78 of whom had undergone rotator cuff repair. The participants were divided into four groups and assigned to usual general physical therapy and an open chain exercise. Group I consisted of the open chain exercise only. The closed chain exercise was applied to group II after the 4 times, group III after the 7 times, group IV after the 10 times. Measurement were used ROM, visual analogue scale (VAS), box and block test (BBT), and shoulder pain and disability index (SPADI). A one-way analysis of variance was conducted to test differences. RESULTS: There were significant differences in the internal/external rotation between group I and group II. The VAS significantly differed between group II and group I, group III, and group IV. The BBT results of group II and group I were significantly different compared to those of group IV. The SPADI significantly differed between group II and group I and between group II and group IV. CONCLUSION: The closed chain exercise was effective for patients following rotator cuff repair from the second week after active exercise was prescribed, verifying its applicability in rehabilitation programs.

• The Journal of Korean Physical Therapy
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• v.27 no.5
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• pp.345-350
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• 2015

Purpose: This study was conducted to determine the effects of ankle joint position during closed kinetic chain (CKC) exercise on knee extensor strength and balance in patients with chronic stroke. Methods: Sixteen patients with chronic stroke participated in the study. Participants were randomly assigned to two groups: $15^{\circ}$ ankle joint plantar flexion group (n=8) and ankle joint neutral group (n=8) during CKC exercise. All participants underwent conventional physical therapy for 30 minutes. In addition, the experimental group ($15^{\circ}$ ankle joint plantar flexion group) and control group (ankle joint neutral group) participated in a 20-minute CKC exercise program. In both groups exercise was performed three times a week for four weeks. Outcomes including knee extensor strength and balance ability (Five times sit-to-stand test, Timed up and go test, and Balancia) were measured before and after exercise. Results: Significant differences in knee extensor strength and balance ability were observed between pre- and post-exercise in all groups (p<0.05). The improvement of knee extensor strength and dynamic balance was significantly higher in the experimental group than in the control group (p<0.05). Conclusion: These findings demonstrated that $15^{\circ}$ ankle joint plantar flexion during closed kinetic chain exercise is effective in improvement of knee extensor strength and dynamic balance in patients with chronic stroke.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.65-70
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• 2016

Purpose: The aim of this study was to determine the effects of electromyographic (EMG)-Biofeedback using closed kinetic chain exercise (EB-CKCE) on quadriceps angle (Q-angle) and quadriceps muscle activation and muscle activation ratio in subjects with patellofemoral pain syndrome and to provide fundamental information on rehabilitation exercise in patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included. The subjects were randomly divided into three groups: control group (Group I, n=10), semi-squat exercise group (Group II, n=10), and EMG-Biofeedback using closed kinetic chain exercise group (Group III, n=10). Intervention was provided to each group for eight weeks (three times per week; 30 minutes per day). Subjects were measured on Q-angle and quadriceps muscle activation. Results: Significant difference in Q-angle and quadriceps muscle activation was observed in groups II and III compared with control group I (p<0.01). Results of post-hoc analysis showed a significant difference in Q-angle and quadriceps muscle activation in on group III compared with groups I and II. Conclusion: Findings of this study suggest that closed kinetic chain exercise using EMG-Biofeedback that provides real-time biofeedback information on muscle contraction may have a beneficial effect on improvement of Q-angle and quadriceps muscle activation in patellofemoral pain syndrome.