• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1229-1232
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• 1996

This paper proposes the passive redundancy algorithm of multi-controller structure applicable to the steam generator level control system in the low power operating range. In the passive redundancy scheme of multi-controller structure, two suitable controllers exist if the plant is strongly stabilizable. One of the two controllers can be selected arbitrarily only if it is stable. In particular, this paper shows that the passive redundancy scheme can be efficiently used with PID and GPC control algorithms through simulation studies on the control of the steam generator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1071-1079
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• 2007

In this paper, a novel space vector control method for isolated multi-level inverter using 3-phase low frequency transformers is proposed. This method is based on the simplification of the space-vector diagram of a five-level inverter using calculated table into fully programming method. The execution time of the proposed method is about same as that of the method using calculated table. Also, the proposed method is easily applied to other case level inverter. We applied this method into the 3-phase IHCML inverter using common arm. It makes possible to use a single DC power source due to employing low frequency transformers. In this inverter, the number of transformers could be reduced compare with an exiting 3-phase multi-level inverter using single phase transformer. In addition, this method generates very low harmonic distortion operation with nearly fundamental switching frequency. Finally, We tested multi-level inverter to clarify electric circuit and reasonableness through Matlab simulation and experiment by using prototype inverter.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.117-124
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• 2002

Fixed distance control system at the railway level crossing have some problem. The problem is especially serious for high speed or low speed train. Therefore present developed device is fixed time control system. But fixed time control system haven't indicate device when train reach at the railway level crossing on alarm. This paper' result in study for train reach spare time indicate device.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.1
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• pp.17-21
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• 2011

This paper presents a real- time detection of on-road succeeding vehicles based on low level edge features and a boosted cascade of Haar-like features. At first, the candidate vehicle location in an image is found by low level horizontal edge and symmetry characteristic of vehicle. Then a boosted cascade of the Haar-like features is applied to the initial hypothesized vehicle location to extract the refined vehicle location. The initial hypothesis generation using simple edge features speeds up the whole detection process and the application of a trained cascade on the hypothesized location increases the accuracy of the detection process. Experimental results on real world road scenario with processing speed of up to 27 frames per second for $720{\times}480$ pixel images are presented.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.203-206
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• 2000

This paper presents a torque ripple reduction technique of direct torque control(DTC) for high power induction motors driven by 3-level inverters with the inverter switching frequency limited around 0.5-1kHz level. It is noted that conventional DTC algorithms to reduce torque ripple are devised for applications with relatively high switching frequency above 2-3kHz. A new DTC algorithms especially for low switching frequency inverter system illustrates relatively reduced torque ripple are devised for applications with relatively high switching frequency above 2-3kHz. Anew DTC algorithm especially for low switching frequency inverter system illustrates relatively reduced torque ripple characteristics Simulation and experimental results show the effectiveness of the proposed control algorithm

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1030-1032
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• 2000

Direct torque control algorithm for 3-level inverter-fed induction motors is proposed. Conventional selection method of the stator voltage vector shows problems of stator flux drooping phenomenon and undesirable torque control appeared especially at the low, speed operation. To overcome these problems, a proposed method uses intermediate voltage vectors, which are inherently generated in 3-level inverters. An adaptive observer is also employed to estimate some state-variables and motor parameters, which takes a deep effect on the performance of the low speed operation. Simulation and experiment results verify effectiveness of the proposed algorithm.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.87-93
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• 2005

This study investigated the response of GLUT -4 and GRP-78 expression in soleus muscle of streptozotocin-induced diabetic rats by imposing different exercise intensities. F344 rats were randomly divided into 4 groups (n=15 in each group): Control (Control), diabetes-operation (DO), diabetes with low intensity exercise (DLE) and diabetes with high intensity exercise (DHE). The rats in DLE and DHE groups were exercised for 8 weeks by treadmill running. Blood glucose levels in DO were significantly higher compared to that in NORMAL whereas DLE showed the most lowest level in blood glucose among diabetic groups. Diabetic groups exhibited significantly lower level in insulin change and DLE showed significantly higher insulin level among diabetic groups. GRP-78 in DO was significantly $(167.05\%)$ higher than that in Control. GRP-78 in DLE was $139.41\%$ which is significantly higher compared to Control but when compared to DO and DHE, it was significant low. GRP-78 in DHE was $194.64\%$ which doubled the protein level in Control and showed the most highest level in all groups. GLUT-4 in DO was significantly $(33.58\%)$ higher compared to Control. GLUT-4 in DLE showed $124.58\%$ which was significant high compared to Control, DO and DHE. GLUT-4 in DHE showed $26.91\%$ compared to Control and was the most lowest level among all groups. It seems clear that chiefly low intensity exercise benefits diabetic patients in controlling blood glucose. It was concluded that low intensity exercise induces translocation of GLUT-4 which results in increased blood inflow, thus GRP-78 expression is decreased.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.1
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• pp.120-127
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• 2007

Purpose: This study was done to identify the level of stress, hardiness, and professional burnout of intensive care unit (ICU) nurses and to provide basic data for the qualitative improvement of nursing work achievement in the workplace. Method: The data were obtained from 129 ICU nurses through a questionnaire. Results: Stress showed positive correlation with the level of professional burnout and there was negative correlation between hardiness and professional burnout. Nurses in the group with a high level of stress, and a high level of hardiness reported a low level of professional burnout compared to those in the group with a lower level of hardiness (t=-2.60, p= .012). Nurses in the group with a low level of hardiness and a low level of stress showed a lower level of professional burnout than those with a high level of stress (t=3.51, p= .001). Conclusion: The results show that the high level of stress when coupled with a low level of hardiness of ICU nurses results in a high level of professional burnout. For this reason, it is important for nursing administration to support nurses to reduce levels of stress and the resulting burnout in ICU nurses.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.38-44
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• 2002

A walking training robot is proposed to provide stable and comfortable walking supports by reducing body weight load partially and a force control of an arm of walking training robot using sliding mode controller is also proposed. The current gait training apparatus in hospital are ineffective for the difficulty in keeping constant unloading level and for the constraint of patients' free walking. The proposed walking training robot effectively unloads body weight during walking. The walking training robot consists of an unloading manipulator and a mobile platform. The manipulator driven by an electro-mechanical linear mechanism unloads body weight in various levels. The mobile platform is wheel type, which allows patients to walt freely. The developed unloading system has advantages such as low noise level, lightweight, low manufacturing cost and low power consumption. A system model fur the manipulator is established using Lagrange's equation. To unload the weight of the patients, sliding mode control with p-control is adopted. Both control responses with a weight and human walking control responses are analyzed through experimental implementation to demonstrate performance characteristics of the proposed force controller.

• The Journal of Korean Physical Therapy
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• v.18 no.6
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• pp.13-21
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• 2006

Purpose: To provide the basic method for physical therapy to contribute to early stage treatment of a burned patients. We investigated whether or not carbon arc lamp treatment and low level laser one among various laser treatments have the effect of reducing Cytokine, and to elucidate the effect of carbon arc lamp treatment and laser one. Methods: The 6-week old BALB/c types of 92 mice were used for the experimental test, and they were burned with $100^{\circ}C$ water, they were divided into 4 groups in accordance with the method of treatment respectively. And the blood and the tissue from the subject of each group were extracted and analyzed each time after they were cured for 3, 6, 9 days. For the analysis of the results, SPSS statistical program was used in this study. Results: The quantity of $TNF-{\alpha}$ and $IL-1{\beta}$ within the blood of a burned mouse increased more than that of a normal mouse(p<0.01). In only a burned mouse, carbon arc lamp treatment gave the effect on the decrease of $TNF-{\alpha}$ thickness the 6th day to the 9th day(p<0.01). $IL-1{\beta}$ quantity was more decreased than that of control group around the 6th day. In comparison with only a control group, low level laser treatment has more significant effect in decreasing the quantity of $TNF-{\alpha}$ a and $IL-1{\beta}$ than the two different methods(p<0.01). In case that the two treatment methods, carbon arc lamp treatment and low level laser, were executed together, there was the effect of decreasing $TNF-{\alpha}$ until the 6th day(p<0.01). Conclusion: Both low level laser treatment and carbon arc lamp one would be able to have an effect on the inflammation inhibition of burned patients and tissues reproduction. However, it must be also considered for the two treatments to be done at the same time.