• Journal of the Korean Society of Physical Medicine
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• v.18 no.3
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• pp.47-53
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• 2023

PURPOSE: A visual feedback method was proposed to induce brain stimulation in a stroke patient, and among them, there was a treatment using a mirror. On the other hand, mirror therapy focuses only on the functional changes in body movements, and analysis of neurophysiological mechanisms of brain activity is lacking. In addition, studies on evaluating the activity and response generated in specific brain regions during visual feedback training using mirrors are insufficient. METHODS: Fifteen healthy adults (male: 10, female: 5, Years: 23.33 ± 1.23), who were right-handed were recruited. By attaching the C3, Cz, and C4 channels in the sensorimotor cortex using an electroencephalogram, training was performed under the conditions without mirror-based visual feedback (No-condition) and with visual feedback (Tasks-condition). At this time, the immediate activity of the mu-rhythm in response to training was separated and evaluated. RESULTS: The tasks-condition of C3, Cz, and C4 channels activated the relative mu-rhythm rather than the no-condition, and all showed significant differences (p < .05). In addition, in all channels at the start time, the tasks-condition was more active than the no-condition (p < .05). The activity of the cortical response was higher in the tasks-condition than in the no-condition (p < .05). CONCLUSION: The mu-rhythm activity can be evaluated objectively when visual feedback using a mirror is applied to healthy subjects, and a basic analysis protocol is proposed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.433-436
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• 2009

This study is concerned with an effect of frictional condition in a forward/backward combined extrusion process. Generally, the material flow of the billet is influenced by the corners of the die cavity, the ratio in reduction in area, and thickness ratio of backward can thickness to forward can thickness. In addition, the frictional condition in contact area between the billet and the punch/die also affect the material flow. This paper investigated the effect of frictional condition for variable friction factors. The FEM simulation has been carried out in order to examine the effect of frictional condition. Deformation patterns and flow characteristics were examined in terms of design parameters such as extruded length ratio etc. Die pressure exerted on the die-workpiece interface is calculated by the simulation results and analyzed for safe tooling. Therefore the numerical simulation works provide a combined extrusion process of stable cold forging process planning to avoid the severe damage on the tool.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1508-1512
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• 2012

This paper presents a relaxed stability condition for continuous-time affine fuzzy system using fuzzy Lyapunov function. In the previous studies, stability conditions for the affine fuzzy system based on quadratic Lyapunov function have a conservativeness. The stability condition is considered by using the fuzzy Lyapunov function, which has membership functions in the traditional Lyapunov function. Based on Lyapunov-stability theory, the stability condition for affine fuzzy system is derived and represented to linear matrix inequalities(LMIs). And slack matrix is added to stability condition for the relaxed stability condition. Finally, simulation example is given to illustrate the merits of the proposed method.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.18-21
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• 2001

In this paper, some geometric condition for a stochastic nonlinear system and an adaptive control method for minimum-phase stochastic nonlinear system using neural network me provided. The state feedback linearization is widely used technique for excluding nonlinear terms in nonlinear system. However, in the stochastic environment, even if the minimum phase linear system derived by the feedback linearization is not sufficient to be controlled robustly. In the viewpoint of that, it is necessary to make an additional condition for observation of nonlinear stochastic system, called perfect filtering condition. In addition, on the above stochastic nonlinear observation condition, I propose an adaptive control law using neural network. Computer simulation shoo's that the stochastic nonlinear system satisfying perfect filtering condition is controllable and the proposed neural adaptive controller is more efficient than the conventional adaptive controller.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.380-381
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• 2008

This paper consider the condition monitoring technology of electrical machine in metro substation need for efficient and effective management and diagnosis. Developing management system using condition monitoring system is very competitive field, and still to a great extent seen as an unnecessary cost. There are several approaches to maintenance management in urban transit such as reliability-centered maintenance, availability-target maintenance and preventive maintenance to advanced approaches involving condition monitoring techniques. In this paper we give a brief introduction to condition-based management and diagnosis in metro substation and which management system satisfying various demanding in railway.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.965-969
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• 1997

Due to the high feed rate,high speed machining (HSM) provide a great potential of rationalization for the machining Dies and Moulds. But determination of cutting condition is very difficult, because cutting mechanism of high speed machining is very complicated,especially using ball end-mill. This paoer gives a report on selection of the optimal cutting condition to improve the machining efficiency, And optimal machining condition is determined through the cutting force, FFT analysis of cutting force and surface roughness according to the cutting condition. Based on this experiment result,wear process and machining characteristics are evaluated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.142-148
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• 2008

This study aims to find the optimal cutting conditions, which are obtained by grinding condition, and the grinding characteristics and condition of constant velocity joint were investigated with respect to wheel velocity, depth of cut, feed speed. Grinding machine has been widely used in manufacturing optical reflects of metal. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of grinding conditions makes good surface roughness and the optimal condition of grinding and get the mesh condition. The purpose of this study is to find the optimum grinding wheel characteristics for cutting constant velocity joint.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.141-144
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• 2006

The building construction is an essential field to consider weather condition because construction works are performed in a site. From this reason, this study evaluated the effect of weather condition with work sections in building construction by Analytic Hierarchy Proces (AHP) method. The results of this study as follows : (1) The effect of weather condition with work sections is affected by rainfall in summer season, and by a low temperature in winter season (2) The effect of weather condition with work sections is 0.235 for mold work, 0.210 for concrete work, 0.181 for steel-frame work.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.7-9
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• 2011

In December 2002, International Maritime Organization (IMO) has adopted the Resolution MSA.137(76) Standards for the Ship Maneuverability. For applying the standards, we have to estimate and evaluate the Maneuverability of a ship at the design stage in difference of trim and displacement as accurate as possible. In this paper, the effect of loading condition on the ship Maneuverability was investigated through 3 methods : numerical simulation, free running model ship and real ship data.. Firstly, We carried out numerical simulation, free running model ship experiments and real ship experiments at ballast condition, half loaded condition and full loaded condition with difference of trim.. Secondly, by comparing these results of 3 methods, we draw out the trend of ship Maneuverability due to the change of trim and displacement of a ship.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.729-736
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• 1997

This paper gives the information of field concrete placed under raining condition. Experimental factors in this study are concrete strength, standard deviation and coefficient of variation. The results are as follows: 1. The strength of field concrete placed under raining condition is not largely dependent on the raining condition. 2. But, the quality of concrete is very critical.