• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1998년도 추계학술대회 논문집
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• pp.224-227
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• 1998

This paper proposes inter-level causal reasoning to implement synergistic approach. We decompose KOSPI prediction model into economy and industry level. Two kinds of intra-level QCOM are combined in inter-level QCOM via Inter-level relations. Downward reasoning is achieved by propagating the disturbance in the higher level to lower level while upward reasoning is to analyze the reverse cases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.62-65
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• 1989

Optimizing transient response for both tracking reference signals and disturbance rejection is determined by the poles and zeros of the transfer function. Thus, optimal pole assignment and how should weighting matrix for the performance index be chosen is very important to achieve optimum transient response. This paper focus its attention on the choosing and analysis of weighting matrix for optimum pole assignment. Optimum pole assignment is defined for linear time-invariant continuous systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.321-325
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• 1986

A new control scheme for the state space model of the robot system using the theory of optimal multi-variable structure is presented in this paper. It is proposed to optimize multi-dimensional variable structure systems for obtaining the required stabilizing signal by minimizing a performance index with respect to the state vector in the sliding mode. It is concluded the proposed variable structure controller yields better system dynamic performance than that obtained by using the only linear optimal controller inthat responses for a step disturbance have a shorter setting time, no matter what overshoot values and rising time.

• Ecology and Resilient Infrastructure
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• 제3권4호
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• pp.285-293
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• 2016

본 연구는 원주천을 대상으로 하천시설물의 최적 설계를 위한 안정하도 평가와 물리적 교란개선 평가를 수행하였다. 안정하도 설계를 위한 구간별 안정경사를 분석하였으며, 안정경사를 만족하기 위한 하천시설물의 개선 시나리오를 도출하였다. 그에 따라 각 시나리오에 대한 물리적 교란개선 평가를 통해 안정하도 설계와 물리적 교란개선을 위한 최적의 시나리오를 선정하였다. 아울러 안정하도 설계와 물리적 교란개선을 위한 하천시설물의 개선 시 물리 서식처의 변화를 분석하였다. 원주천의 하천 환경조사와 어류의 군집특성을 이용하여 수중 생태계를 대표할 수 있는 복원 목표어종으로 참갈겨니를 선택하였다. 참갈겨니의 서식적합지수를 사용한 서식적합도 분석은 PHABSIM 모형을 이용하였다. 예측 평가를 수행한 결과 서식적합도와 가중가용면적은 소폭 감소하는 것으로 나타났으나, 하천시설물의 개선에 따른 영향은 아닌 것으로 나타났다. 따라서 원주천의 물리적 건전성과 안정성을 제고할 수 있는 하천시설물의 배치 방안을 제시하였으며, 그에 따른 물리 서식처의 변화는 영향이 없는 것을 확인하였다.

• Journal of Astronomy and Space Sciences
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• 제28권2호
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• pp.123-132
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• 2011

It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME)-driven storms, co-rotating interaction region (CIR)-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF $B_y$ and $B_z$ components (in geocentric solar magnetospheric coordinate system coordinate) during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst) index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of $B_z$ < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF $B_z$ (T1~T4) is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0%) under the $B_z$ < 0 condition. It is found that the correlation is highest between the time-integrated IMF $B_z$ and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is found between timeintegrated $B_z$ and time-integrated Dst index. The relationship between storm size and time lag in terms of hours from $B_z$ minimum to Dst minimum values is investigated. For the CME-driven storms, time lag of 26% of moderate storms is one hour, whereas time lag of 33% of moderate storms is two hours for the CIR-driven storms. The average values of solar wind parameters for the CME and CIR-driven storms are also examined. The average values of ${\mid}Dst_{min}{\mid}$ and ${\mid}B_{zmin}{\mid}$ for the CME-driven storms are higher than those of CIR-driven storms, while the average value of temperature is lower.

• Journal of Oral Medicine and Pain
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• 제31권1호
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• pp.91-99
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• 2006

최근까지 수면과 stress 만성 동통에 관한 많은 석학들의 연구가 이루어져 왔다. 만성적인 구강안면 통증의 조절에 있어 단지 치료실내의 치료만으로는 반응하지 않는 치과적 원인만이 아닌 중요한 다른 원인이 존재하는 다양한 임상 증례를 접함에 있어 만성 통증을 유발 할수 있는 수면 장애에 대해 조사하여 구강안면 통증 환자의 진단과 치료에 있어 유용한 정보를 제공하고자 한다. 수면은 극히 개인적인 과정이며 같은 수면 양태를 지닌 사람은 거의 없다. 이렇듯 다양한 수면 양태를 Pittsburgh sleep quality index를 이용하여 주관적 수면의 질, 수면 잠복기, 수면 장애, 수면 효율, 수면제의 사용, 주간 기능 장애를 분석하여 총 수면 지수와 구강 안면 통증 양상을 연구하였다. 101명에게 PSQI 설문지와 behavioral pain scale을 이용하여 수면력과 두경부 통증과 통증의 확산, 두통과 수면, 통증에 대처 하는 방법등에 대해 조사하였다. 이에 본 연구에서 양호한 수면자와 불량 수면자에 따른 수면의 질 통증 환자군, 두통이 있는 군, 전신적 약 복용, 습관적으로 카페인 함유 음료를 마시는 대상에게서 수면 장애가 있음을 보여 주었고 불량 수면자에게서 두경부 통증과 통증의 확산, 운동시 통증 등의 빈도가 더 높았음을 보여주었다. 통증을 해소 하는 방법은 그냥 쉰다 등 으로 적극 적이지 못했으며, 추후 수면이 통증 해소에 도움이 될수 있는 지에 따른 연구가 필요하리라 생각된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3128-3133
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• 2007

The mixing method of water and chemicals is significant in a small-scale water supply system because drinking water should be supplied with a certain quantity of remaining chemicals maintained. In the present study, the concentration distribution and the mixing index were obtained from four models, which were to find out the optimal mixing method of water and chemicals. The two models brought the good mixing effects out of the four, one for providing chemicals from the center of water supply pipe and the other for setting up the semicircle block at the downstream of the chemicals-providing pipe. As a result, the mixing effect was found out to be increased due to the diffusion and the disturbance of flows. In conclusion, these results are expected to contribute to designing the optimal mixing system.

• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.581-589
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• 2009

In a two-inertia motor system with flexible shaft, a torsional vibration is often generated as a quick speed response is required. This vibration makes it difficult to achieve a quick response of speed and disturbance rejection. The objective of this paper is to provide a systematic analysis and design of the three kinds of speed controllers such as I-P, I-PD, and state feedback control by using the weighted ITAE performance index. Some simulation and experiment results verify the effectiveness of the proposed design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1103-1105
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• 1997

Transient stability analysis is concerned with a power system's response to unwanted disturbance. Recently, direct method which utilize the stable region of stable equilibrium point is used to analyze transient stability This paper focuses on the controlling UEP method using the fractal behaviours. In the controlling UEP method, many algorithms are used to find controlling UEP However, the existence of fractal region gives difficulty in finding the controlling UEP. So, this paper observes the fractal feature arid introduce the fractal index to explain how much the fractal region occupies in the entire space. Using an improved algorithm from the view point of fractal index, we are going to find the controlling UEP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.1976-1978
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• 2001

In this paper, a new robust deadbeat minimax FIR filter (DMFF) is proposed for continuous-time state space signal models. Linearity, deadbeat property, FIR structure, and independence of the initial state information will be required in advance, in addition to a performance index of the worst case gain between the disturbance and the current estimation error. The proposed DMFF is obtained by directly minimizing a performance index with the deadbeat constraint. The proposed DMFF is represented first in a standard FIR form and then in an iterative form. The DMFF will be shown to be used also for the IIR structure. It is shown that the DMFF is similar in form to the existing receding horizon unbiased FIR filter (RHUFF) with some noise covariances. The former is a deterministic filter, while the latter is a stochastic filter.