• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.494-501
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• 1999

In this research, ANN modeling method of SMES unit is developed for stability analysis, and the optimal site is selected to maximize stabilization effect of SMES unit. The ANN is trained by learning data which is obtained through the application of complex test function into the traditional mathematical mode. In order to verify the validity of proposed modeling method, fault data of sample power system is applied to both the traditional and the ANN models. When the response of traditional and proposed models are compared, the average error for the active and reactive power are 2.51[%], and 0.24[%], respectively. From the comparison, the relevance of proposed method is validated. For the transient stability analysis, an application method of the proposed model is presented, and the transient stability performance index, which describes system stabilization effect of SMES at disturbance, is also suggested, and optimal site selection method of SMES is presented. In the viewpoint of the voltage stability, system stabilization criterion of local bus is presented from P­V curve, and then optimal site which can maximize the voltage stabilization of the whole power system, is decided from the proposed voltage stability performance index.

• Physical Therapy Korea
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• v.23 no.4
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• pp.38-46
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• 2016

Background: Shoulder stabilization commonly involves two components: the glenohumeral stabilization exercise (GSE) and scapular stabilization exercise (SSE). Despite the fact that the shoulder stabilization has advantageous merit, to our knowledge, only a few studies have compared the superior of the GSE and the SSE. Objects: The purpose of this study was to assess the effects of GSE in patients with nonspecific shoulder pain. Methods: Thirty subjects with nonspecific shoulder pain were randomly divided into an experimental group and control group, each with 15 patients. The experimental group used an GSE, whereas the control group did SSE. All subjects were measured in shoulder stability, scapular symmetric alignment, pain, muscle power, and range of motion before and after the intervention. Results: GSE resulted in significantly better shoulder stability (p=.046, from $8.67{\pm}7.54$ score to $13.93{\pm}9.40$) in the experimental group compared with SSE in the control group. However, no significant effects were observed for scapular symmetric alignment including the angles of inferior scapular distance (p=.829) and inferior scapular height difference (p=.735), pain (p=.113), muscle power including shoulder flexion (p=.723) and abduction (p=.897) and range of motion including shoulder flexion (p=.853) and abduction (p=.472). Conclusion: These findings suggest that GSE may be more effective in increasing the shoulder stability than the SSE in patients with nonspecific shoulder pain, probably through a centralization effect on the shoulder mechanism.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.432-437
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• 1998

Power systems have uncertain dynamics due to a variety of effects such as lightning, severe storms and equipment failures. The variation of the effective reactance of a transmission line due to a fault is an example of uncertainty in power system dynamics. Hence, a robust controller to cope with these uncertainties is needed. Recently fuzzy controllers have become quite popular for robust control due to its capability of dealing with unstructured uncertainty. Thus in this paper we design an adaptive fuzzy controller using an input-output linearization approach for the transient stabilization and voltage regulation of a power system under a sudden fault. Simulation results show that satisfactory performance is achieved by the proposed controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.11
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• pp.1555-1561
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• 2018

Tracking and detecting targets by the millimeter wave seeker is affected by movement of platform. Stabilization equipments use an inertial sensor to compensate for disturbance of stabilizing gimbal or platform. In the direct line of sight stabilization system, an inertial sensor is mounted on inner gimbal to compensate the disturbance directly, so the performance is excellent and the implementation method is simple. However gimbal design requires somewhat larger volume. Since an inertial sensor is mounted on gimbal base in the indirect line of sight stabilization system, additional space of gimbal is not required for the gimbal design. However, this method does not directly compensate for the disturbance of the line of sight stabilization axis, which can degrade performance. In order to perform the tracking performance, two methods are analyzed for line of sight stabilization performance based on direct and indirect of a 2-axis gimbaled servo system for millimeter wave seeker in this study. The simulation and experimental results validate the performance comparison of two methods.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.2
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• pp.47-54
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• 2015

Purpose: This study was to investigate the effects of lumbar stabilization exercise and lower extremity strengthening program on pain, lower extremity muscle in patients with chronic low back pain. Method: The subject were randomly divided two groups. 15 people who were conducted lower extremity exercises and lumbar stabilization exercises called the combined exercise group and other(15 people) who were only conducted lower extremity exercise group. The assessment tools were the pain level and the led muscle power. Exercise was conducted for eight weeks. Result: Pain of the combined exercise group showed significant differences in the change in pain level(p<.05). The leg muscle power showed significant differences within group which hip flexor, extensor muscles and abductor muscles. there were significant differences within combined exercise group (p<.05). But the knee joint in each group showed a significant difference within group (p<.05). Conclusion: This study suggest that the lumbar stabilization exercises and lower extremity exercises showed more efficient results in the pain levels and leg muscles power than only the lower extremity exercise for patients with lumbar instability.

• Proceedings of the KIEE Conference
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• 2005.11c
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• pp.131-135
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• 2005

Stabilization of electric power is the most important thing is such place as computing center having business critical equipment. However, ability to cope with electrical quality shift and power failure is very weak from UPS output side to load in those electricity system, though UPS is generally used for power stabilization. this problem can be solved by duplication of power source using newly configured UPS and small sized transfer switch even in case of UPS failure.

• International Journal of Control, Automation, and Systems
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• v.3 no.spc2
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• pp.308-314
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• 2005

Transient stabilization with voltage regulation is investigated for a synchronous generator when the mechanical power is perturbed to any unknown value within its physical bounds so that the operating point of the system shifts to an unknown point. An adaptive excitation controller is designed based on the backstepping method with tuning functions. It will be shown that the adaptive control law proposed can achieve the convergence of the system states to the new equilibrium point in correspondence with the real value of the unknown mechanical power and the regulation of the terminal voltage to the required value. Simulation results are given to demonstrate the effectiveness of the proposed controller for the transient stabilization and voltage regulation.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.875-879
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• 1998

A fault on the transmission line results in the variation of reactance and parametric uncertainties in the power system dynamics. In this case, we need a robust control to cope with these uncertainties. A sliding mode control, a sort of robust control, is known to be robust to parametric or state-dependent uncertainties if the bounding function of uncertain terms is determined a priori. However, in general, we can not readily determine the bounding function for the complex systems. Hence, in this paper we introduce a fuzzy system which can estimate the bounding function in relatively simple way. By the use of the proposed fuzzy system, determination of bounding function is made easier. We applied the proposed scheme to the stabilization of power system under the sudden fault on the transmission lines. The simulation result verifies the effectiveness of the scheme.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1178-1179
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• 2008

This paper describes a modeling of fixed speed wind power generation system which comprise of wind turbine, generator and grid. The wind turbine is based on MOD-2, which is IEEE standard wind turbine, and includes a component using wind turbine characteristic equation. Fixed speed induction generator is directly connected to grid, so the variation of wind speed has effects on the electrical torque and electrical output power. Therefore the power control mode pitch control system is necessary for aerodynamic control of the blades. But the power control mode does not operate at the fault condition. So it is required some methods to control the rotor speed at transient state for stabilization of wind power system. In this paper, simulation model of a fixed speed wind power generation system based on the PSCAD/EMTDC is presented and implemented under the real weather conditions. Also, a new pitch control system is proposed to stabilize the wind power system at the fault condition. The validity of the stabilization method is demonstrated with the results produced through sets of simulation.

• Journal of Korea Entertainment Industry Association
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• v.14 no.3
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• pp.475-482
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• 2020

The abdominal drawing-in maneuver(ADIM), which is performed to strengthen the stabilization muscles of the lumbar, is an exercise method that selectively contracts the TrA and IO by increasing intra-abdominal pressure. In order to check the effect of ADIM in sitting position, which is the most frequently used posture in everyday life, on how to grip power, ADIM was conducted in a sitting position for 30 healthy adults, and then the state was not performed. In each, the grip power was measured to determine how ADIM performed in the sitting position had an effect on grip power and which muscles had the most influence. The muscles mobilized for the electromyography(EMG) measurement were RA, EO, IO/TrA, and ES, which were the most activation lumbar stabilization muscles when ADIM was applied. As a result of the study, the activity on muscles of the lumbar stabilization was significantly increased and the grip power of the muscles was significantly increased than the ADIM in the sitting position. By comparing the measured difference value of each muscle, it was found that any muscle had a greater effect on grip power, but no muscle showed a significant correlation. It is thought that the increase of intra-abdominal pressure did not affect the grip power of a specific muscle. Therefore, if ADIM is performed in a sitting position that is frequently used in everyday life through this study, it will be more effective in increasing the grip power and lumbar stabilization.