• Journal of Power Electronics
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• 제9권3호
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• pp.456-463
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• 2009

The paper presents a method for controlling induction motors using a nonlinear internal model control (IMC) approach. The process model and the inverse model are developed in the rotor flux coordinate. The main advantage of the proposed method is that it easily specifies the performance (steady state error, transient response, etc.) and the robustness of the controller by means of the IMC filters. Simulation results illustrate the effectiveness of the proposed method. Results on a real time system show that the control system has good performance and robustness against changes in motor parameters (rotor and stator resistances, rotor and stator inductances, rotor inertia).

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.515-525
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• 2008

In this paper, the problem of delay-dependent stabilization for singular systems with multiple internal and external incommensurate constant point delays is investigated. The condition when a singular system subject to point delays is regular independent of time delays is given and it can be easily test with numerical or algebraic methods. Based on Lyapunov-Krasovskii functional approach and the descriptor integral-inequality lemma, a sufficient condition for delay-dependent stability is obtained. The main idea is to design multiple memoryless state feedback control laws such that the resulting closed-loop system is regular independent of time delays, impulse free, and asymptotically stable via solving a strict linear matrix inequality (LMI) problem. An explicit expression for the desired memoryless state feedback control laws is also given. Finally, a numerical example illustrates the effectiveness and the availability for the proposed method.

• International Journal of Safety
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• 제5권2호
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• pp.6-11
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• 2006

The time delay in servo control on LonWorks/IP Virtual Device Network (VDN) is highly stochastic in nature. LonWorks/IP VDN induced time delay deteriorates the performance and stability of the real-time distributed control system and hinders an effective preventive and predictive maintenance. Especially in real-time distributed servo applications on the factory floor, timely response is essential for predictive and preventive maintenance. In order to guarantee the stability and performance of the system for effective preventive and predictive maintenance, LonWorks/IP VDN induced time delay needs to be predicted and compensated for. In this paper position control simulation of DC servo motor using Zero Phase Error Tracking Controller (ZPETC) as a feedforward controller, and Internal Model Controllers (IMC) based on Smith predictor with disturbance observer as a feedback controller is performed. The validity of the proposed control scheme is demonstrated by comparing the IMC based on Smith predictor with disturbance observer.

• 대한한방내과학회지
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• 제26권1호
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• pp.156-168
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• 2005

Objective : The purpose of this research is to examine the effects of Pinelliae Rhizoma (PR) extract on immune cells and cytokines in ovalbumin (OVA)-induced asthmatic mice. Methods : In vivo, C57BL/6 mice were sensitized and handicapped by OVA for 12 weeks. During this experiment, the one group was then treated with PR extract for the 8 weeks (3 times per week) and analyzed by ELISA and flow cytometer. Results : In vivo, there were significant decreases in eosinophils, IL-4, IL-5, IL-13, IgE in BALF (bronchoalveolar lavage fluid) compared with that of control group. However, $IFN-{\gamma}$ in BALF of GS group increased significantly, compared with that of control group. Additionally, the population of $CD3e^-/CCR3^+,\;CD69^+/CD3e^+,\;IgE^+/B220^+,\;CD11b^+/Gr-l^+$ cells in the PR group decreased, compared with that of control group. Conclusion : The results of this study support a role for PR as an effective treatment for asthma in its experimental success in significantly decreasing inflammation and asthma reactions, and in increasing $IFN-{\gamma}$, which helps prevent such reactions.

• 동력기계공학회지
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• 제18권1호
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• pp.7-13
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• 2014

• 전산구조공학
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• 제9권3호
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• pp.125-134
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• 1996

건물기초를 지진절연하면 건물뿐만 아니라 그 내부구조물의 지진응답도 크게 감소한다는 사실이 많은 연구를 통해 확인되어 왔다. 그런데 이러한 내부구조물이 유체내에 잠기고 부가질량효과가 크게 작용되는 조건에 놓이는 경우 오히려 지진응답이 증가할 수 있다. 본 논문은 건물 내 수중구조물의 지진해석을 통해 그러한 예를 제시하고자 한다. 해석결과 지진절연된 건물의 경우 이러한 내부 수중구조물의 지진응답이 상당히 증가할 수 있기 때문에 이에 대한 조치가 필요함을 보였고, 적절한 설계에 의하여 부가질량효과를 조절함으로써 어느정도 응답을 줄일 수 있다는 사실을 알 수 있었다.

• 동의신경정신과학회지
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• 제20권4호
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• pp.127-135
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• 2009

Objectives : This study was conducted to assess the effect of Chunwangbosim-dan(CB) on the autonomic nervous system by using heart rate variability measurement. Methods : The eligible subjects were composed of the healthy female group of ages 25 to 30 years. They were divided into two groups, the CB group(n=16) and the control group(n=16). We measured the heart rate variability respectively for 3 times at 14:00, 16:00, and 17:00. In the CB group, subjects were administered CB at 15:00. For the measurement values, Mean Heart Rate and SDNN(standard deviation of the NN intervals) were used as time domain analysis, and HF(high frequency), LF(low frequency), and LF / HF ratio were used as frequency domain analysis. Results : The degree of LF changes in the CB group was significantly lower than control group at 1 hour after administration. Conclusions : We suggest that Chunwangbosim-dan may be useful for stabilization of the autonomic nervous system by controlling sympathetic nerve in healthy people.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.142-147
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• 1988

Free-path-type guidance system does not need a hardwired path in the environment so that it gives a mobile robot a flexible path. ln this study to achieve the free-path-type guidance system for a mobile robot which is steered by the differential steering of both drive forewheels, position recognition systems are constructed using odometer system as an internal position sensor. Two odometer systems, a auxiliary wheel odometer and a 2-encoder odometer system are constructed and path following algorithms using these odometer systems are designed and experimented. PID control type is adopted in the path following algorithms.

• 한국산학기술학회논문지
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• 제10권6호
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• pp.1353-1360
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• 2009

본 논문은 회계부정 등 내부통제의 부실로 인한 외부 정보이용자들과 자본시장의 악영향을 최소화하는 것을 목적으로 하는 회계투명성 방안 중 하나인 내부회계관리제도의 시행실태와 효과를 검증하기 위하여 수행되었다. 2005년부터 2007년까지의 연구기간동안 내부회계관리제도시행에 따른 지적기업과 비지적기업으로 분류하여 재무적인 특성에 차이가 존재하는지 검증하고, 비교적 회계부정이 발생하기 쉬운 지적기업과 표준보고를 한 기업의 발생액 차이를 알아봄으로써 이익조정에 대한 가능성을 예측해 보려하였다. 연구의 결과로서 특성지표 중 코스피시장의 경우는 유동비율과 메출액순이익률만이 유의한 것으로 나타났다. 코스닥시장의 경우는 부채비율과 유동비율이 통계적으로 의미 있는 것으로 나타났다. 이로서 부분적으로 가설1을 지지하는 결과를 보였다. 두 번째 가설도 재량적발생액의 경우 지적기업이 비지적기업보다 더 크게 나옴으로써 지지하는 것을 알 수 있었다.

• 설비공학논문집
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• 제27권6호
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• pp.313-320
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• 2015

In this paper, a method to obtain the probability distribution of room temperature and cooling load is presented, when the internal heat generation is applied to the system as a disturbance in the air conditioning system with slab cooling storage. The probability distribution of room temperature and the cooling load due to the disturbance were examined in one room of an office building. When considering only the electric power consumption as a probability component, it was found that the effect on room temperature and cooling load is small, because the probability component of the measured electric power consumption in the building is small. On the other hand, when considering the stochastic fluctuations of electric power consumption together with the heat generated by human bodies, the mean value of the cooling load was about 2,300 W and the ratio of the standard deviations was 19% (10 o'clock in second day). It was revealed that the stochastic effects of internal heat generation acting on the air conditioning system with slab cooling storage are not small.