• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1009-1012
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• 1995

This paper presents an example of the development of motor drives for machine tools. Machine tools need motor drives with high control precision and performance. We developed a motor drive system that meets these requirements. The converter, the one component of drive system, adopts modular structure and high DC-link voltage. The drive which consists rest part of drive system is developed based on TMS320C32 DSP and state-of-the-art circuit technology. In this paper each developed parts are described in terms of its structure, specification and features.

• Journal of Power Electronics
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• v.10 no.1
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• pp.58-64
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• 2010

In this paper, the dynamic performance of oscillating linear motors, which are used in household refrigerators, is improved by means of efficient parameter identification. Oscillating linear motor parameters are identified as a function of the piston position and the motor current. They are stored in a ROM table and used later for an accurate estimation of piston position. The identified motor parameters are also approximated to the $2^{nd}$-order surface functions, which are divided into 2 or 4 subsections in order to decrease identification errors. Experimental results are given to show that the proposed control scheme can provide oscillating linear motors with high dynamic performance.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1007-1014
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• 2015

An optimally designed six-phase induction motor (6PIM) is compared with an initial design induction motor having the same ratings. The Genetic Algorithm (GA) method is used for optimization and multi objective function is considered. Comparison of the optimum design with the initial design reveals that better performance can be obtained by a simple optimization method. Also in this paper each design of 6PIM, is simulated by MAXWELL_2D. The obtained simulation results are compared in order to find the most suitable solution for the specified application, considering the influence of each design upon the motor performance. Construction a 6PIM based on the information obtained from GA method has been done. Quality parameters of the designed motors, such as: efficiency, power losses and power factor measured and optimal design has been evaluated. Laboratory tests have proven the correctness of optimal design.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1027-1028
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• 2007

In this paper, the variation of air-gap field intensity caused by the slot-opening in interior permanent magnet (IPM) motor is investigated, which is for predicting the instantaneous magnetic field more preciously in analytical method further. It is different with the approach of dealing the slot-opening effect on the air-gap field distribution with the "relative permeance" function in surface permanent magnet (SPM) motor. The prediction of the air-gap field in IPM motor is much more complex than SPM motor. In this study, an approximate estimation method is adopted based on analyzing the changing of flux path in both the IPM rotor part and stator part, and in additional an analytical function defined as "relative pole-arc" is built. The finite element method(FEM) is used for confirming the slot-opening effect on the field prediction.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.2
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• pp.74-80
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• 2003

In this paper, a robust two-degree-of-freedom(TDF) the speed control system using $H_{\infty}$ optimization method and real genetic algorithm is proposed for the robust stability and the robust performance in dc servo motor system. This control system composed of feedback and feedforward controller. The feedback(FB) controller with $H_{\infty}$ optimization method is designed for real genetic algorithm that is model matching problem using mixed sensitivity function. The feedforward(FF) controller with $H_{\infty}$optimization method is minimized the error between transfer function of the optimal model and the overall transfer function. The proposed robust two-degree-of-freedom speed control system is simulated to the dc servo motor. By the simulation, feedback controller can obtain the robust stability property and feedforward controller can obtain the robust performance property under modelling error. The performance of the dc servo motor is analyzed by the experiment setting. The validity of the proposed method is verified through being compared with pid(proportional integrated differential)control system design method for the dc servo motor.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.2
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• pp.281-288
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• 2010

Purpose : The purpose of this study was to examine the correlation between Pediatric Balance Scale(PBS) and Gross Motor Function Measurement(GMFM) with cerebral palsy(CP) children. Methods : 31 ambulatory children with CP were recruited for this study. PBS is a modified version of the Berg’s Balance Scale to access the children with motor impairments. To access the motor functions that directly influence to the functional independence of the ambulatory CP children, total scores of standing category and walking/running/jumping category of GMFM were selectively compared with PBS score by Spearman correlation coefficient analysis. Results : The results revealed high correlation between PBS and GMFM scores both in standing and walking/running/jumping categories(r=.9). Conclusions : Therefore, this study indicates that PBS can be applied not only as a tool to access balance, but also as a measurement to predict and access the level of standing and ambulatory related functions of children with CP.

• Journal of Korean Medicine Rehabilitation
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• v.18 no.3
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• pp.1-17
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• 2008

Objectives : Ohyaksungi-san(Wuyaoshunqi-san) has been used for many years as a treatment for cerebrovascular diseases in Oriental medicine. This study was designed to evaluate the effects of Ohyaksungi-san(Wuyaoshunqi-san) on cognition and motor function recovery after ischemic brain injury, and also the expression of BDNF in hippocampus. Methods : This study was designed with 4 subgroups to evaluate the effects of Ohyaksungi-san(Wuyaoshunqi-san). As control groups, group I has no treatment during 1 week after ischemic brain injury and group II has no treatment during 2 weeks after ischemic brain injury. As experimental groups, group III has been treated with Ohyaksungi-san(Wuyaoshunqi-san) during 1 week after ischemic brain injury and group IV have treated with Ohyaksungi-san(Wuyaoshunqi-san) during 2 week after ischemic brain injury. Each group has been examined by tests as follows, neurological motor behavioral tests, cognitive motor behavior test and histological test. Neurological motor behavior tests consisted of limb placement test, beam-walking test and horizontal wire test. Cognitive motor behavior test was performed by using Morris water maze. In the histological test, TTC(2,3,5-triphenylteterazolium chloride) staining, hematoxylin & eosin staining, and immunohistochemical staining were used. Results : 1. The tests for motor function recovery change had significantly good result in the experimental groups as compared with control groups(p<.05). 2. The Morris water maze test on cognition also had significantly good result in the experimental groups as compared with control groups(p<.05). 3. In the immunohistochemical staining for the expression of BDNF in hippocampus, more immune reaction was investigated in the experimental groups as compared with control groups. Especially group IV has the greatest immune reaction. Conclusions : Ohyaksungi-san(Wuyaoshunqi-san) has good effects on cognition and motor function recovery after ischemic brain injury, and also the expression of BDNF in hippocampus.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.2
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• pp.171-179
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• 2014

PURPOSE: The objectives of this study were to investigate the effects of physical therapy provided at home on the motor function, activity of daily living (ADL), and level of pain in veterans men with disabilities, and to provide the information. METHODS: The participants were 108 patients men with disabilities living in the cities Seoul, Pusan, Daegu, Gwangju and Daejeon; they performed physical therapy at home-provided by physical therapy services- that included therapeutic exercise for 50 minute, 1~2 times a week for 24 weeks. The motor function was measured by using motor assessment scale (MAS) and ADL, the level of pain were recorded both before and after physical therapy. The data form both before and after physical therapy were analyzed by using the paired t-test. All statistical tests in this study were performed with the level of significance set at .05. RESULTS: After 24 weeks of physical therapy, we observed significant improvement in the MAS and ADL scale, as well as significant decrease in the level fo pain in the participants (p<.01). Significant improvement was also observed in the MAS and ADL scale, as well as a decrease in the level of pain among participants with stroke and spinal disease (p<.05). CONCLUSION: The findings of this study show that physical therapy provided at home can lead to an improvement in the motor function as well as improved ADL and pain control; physical therapy also has positive effects in relieving symptoms of veterans with disabilities.

• PNF and Movement
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• v.3 no.1
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• pp.1-15
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• 2005

Objective : The purpose of this study was to evaluate the influence of a community based group exercise intervention on motor functional capacity. To evaluate the immediate(post-treatment) effects after 6-weeks exercise program on the group exercise intervention(PNF and Circuit exercise). Methods : Subjects-Included persons with stroke who were living in the community. Thirty-seven subjects were randomly assigned to the PNF, Circuit exercise and control group participated in a repeated measures design that evaluated the subjects with pre-treatment, post-treatment(6 weeks). Functional ability outcome measures assessed the motor assessment scale(MAS) and EMG. Both treatment groups participated in exercise cJass three times a week for 6 weeks. Group programs focused on balance, functional motor capacity and walking ability. The PNF program was modified PNF pattem and techniques with emphasis on functional tasks when possible, as well as stretching of the more affected limb particularly in the more affected shoulder. The Circuit program with subjects completing practice at a selies of work station as well as participating in walking races and relay with other members of the group. Results : Compared with the control group, the treatment group had larger improvements in the motor function ability after 6 weeks treatment and Post-treatment test scores were more significant than the pre-treatment score. 1. Motor function were assessed by using MAS, sit to stand, walking and upper function were assessed pre-treatment versus post-treatment measures revealed a statically significant(p<.05). There were significant differences between the groups. Compared with the control group, the treatment group had larger improvements. 2. In the treatment groups, demonstrated difference in the electromyographic activation of biceps, triceps, quadriceps and tibialis anterior muscles on the paretic side in the response to the reaching arm movement and stepping motion in stance. The difference in muscle activation improvement were not statically significant. Conclusion : The results of this study showed that the PNF and Circuit group exercise intervention can improve motor functional ability. This study suggests that the PNF and Circuit exercise programs is appropriate for community-based group exercise principles. It leads to gain and maintain potential function for disabled persons after stroke in the community.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.3
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• pp.385-394
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• 2010

Purpose : The present study was to examine the difference and severity of asymmetry in independently ambulating stroke survivors and to establish the association between gait asymmetry, velocity, and the motor function of lower extremity. Methods : The subjects used in this study were 43 subjects with hemiparesis being able to walk independently. Motor function of lower extremity was measured clinically with the Fugl Meyer-Lower /Extremity Assessment. Overground gait velocity and spatia-temporal parameters were collected by the GAITRite system. Results : Thirty(69.77%) patients showed statistically significant temporal asymmetry while 28(65.1%) exhibited statistically significant spatial asymmetry. One-way ANOVA results showed a main effect of temporal asymmetry group(normative, mild, severe) for gait velocity(F=74.129), FM-L/E(F=17.270), swing-stance symmetry(F=66.869, F=13.485, respectively), spatio-temporal asymmetry(F=13.166, F=31.800, respectively) 66, F=31.800, respectively). Gait velocity was negatively associated with temporal asymmetry(r=-.83), spatial asymmetry(r=-.60). Motor function of lower extremity was also associated with temporal asymmetry(r=-.58), and spatial asymmetry(r=-.50). Conclusion : The study attempted to establish the standard assessment of hemiparesis gait symmetry in light of the complex relationship with motor impairment and gait velocity. More future work will need to link the degree of gait asymmetry to clinically relevant outcomes to better establish the clinical significance of such observations.