• 응용통계연구
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• 제1권2호
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• pp.27-33
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• 1987

감마분포에 따르는 K($\geq$2)개의 처리들 중에서 최대 척도모수를 갖는 처리를 선택하는 제거형 이단 선택방법을 제안하고 주어진 $(\delta^*, p^*)$에 대하여 Kim(1985)이 제안한 선택확률의 하한을 만족할때 설계상수(nr, mr, c)와 총실험횟수의 평균을 Monte Carlo 방법으로 구하였다. 또한 총실험횟수를 작게한다는 점에서 일단 선택방법보다 유용함을 밝혔다.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.126-132
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• 2012

본 연구에서는 강인한 성능을 가지는 모델추종형 H${\infty}$ 제어기의 설계법을 제시한다. 이를 위해 강인한 성능을 보장하는 해집단내에서 기준모델의 출력을 최적으로 추종하도록 유전 알고리즘을 사용하여 가중치 함수와 설계 파라미터 ${\gamma}$를 동시에 최적화한다. 설계된 H${\infty}$ 제어기는 강인한 성능에 관한 필요충분조건식을 만족함은 물론 설계사양에 따른 만족스러운 응답특성을 가진다. 제시된 방법을 보일러-터빈 제어 시스템에 적용하여 그 유용성을 확인한다.

• 한국농공학회지
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• 제35권3호
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• pp.100-116
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• 1993

It is experienced fact that unreasonable design criterion and unsitable operation management for the agricultural structures including reservoirs based on short terms data of monthly flows have been brought about not only loss of lives, but also enormous property damage. For the solution of this point at issue, this study was conducted to simulate long series of synthetic monthly flows by multi-season first order Markov model with selection of best fitting frequency distribution and to make a comparison of statistical parameters between observed and synthetic flows of six watersheds in Yeong San and Seom Jin river systems. The results obtained through this study can be summarized as follows. 1.Both Gamma and two parameter lognormal distribution were found to be suitable ones for monthly flows in all watersheds by Kolmogorov-Smirnov test while those distributions were judged to be unfitness in Nam Pyeong of Yeong San and Song Jeong and Ab Rog watersheds of Seom Jin river systems in the $\chi$$^2$ goodness of fit test. 2.Most of the arithmetic mean values for synthetic monthly flows simulated by Gamma distribution are much closer to the results of the observed data than those of two parameter lognomal distribution in the applied watersheds. 3.Fluctuation for the coefficient of variation derived by Gamma distribution was shown in general as better agreement with the results of the observed data than that of two parameter lognormal distribution in the applied watersheds both in Yeong San and Seom Jin river systems. Especially, coefficients of variation calculated by Gamma distribution are seemed to be much closer to those of the observed data during July and August. 4.It can be concluded that synthetic monthly flows simulated by Gamma distribution are seemed to be much closer to the observed data than those by two parameter lognormal distribution in the applied watersheds. 5.It is to be desired that multi-season first order Markov model based on Gamma distribution which is confirmed as a good fitting one in this study would be compared with Harmonic synthetic model as a continuation follows.

• ETRI Journal
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• 제31권5호
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• pp.604-606
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• 2009

The primary dose effects on an insulated gate bipolar transistor (IGBT) irradiated with a $^{60}Co$ gamma-ray source are found in both of the components of the threshold shifting due to oxide charge trapping in the MOS and the reduction of current gain in the bipolar transistor. In this letter, the IGBT macro-model incorporating irradiation is implemented, and the electrical characteristics are analyzed by SPICE simulation and experiments. In addition, the collector current characteristics as a function of gate emitter voltage, VGE, are compared with the model considering the radiation damage of different doses under positive biases.

• 한국지능시스템학회논문지
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• 제14권3호
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• pp.316-323
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• 2004

이 논문에서는 특이섭동 T-S 퍼지시스템의 $H_{\infty}$ 출력 궤환 제어기의 설계를 취급한다. 특이섭동 시스템에서 저속 부시스템과 고속 부시스템의 $H_{\infty}$ 노옴이 각각 ${\gamma}$ 보다 적다면 충분히 적은 ${\varepsilon}$>0에 대해서 특이섭동 퍼지시스템의 $H_{\infty}$ 노옴이 ${\gamma}$보다 적음을 증명한다. 이러한 사실을 이용하여 특이섭동 파라메터 ${\varepsilon}$과 무관한 선형 행렬부등식을 기반으로하는 제어기 설계법을 제시한다. 제시된 설계법의 효용성을 입증하기 위하여 수치예를 보여준다.

• 한국주조공학회지
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• 제31권4호
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• pp.186-190
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• 2011

A new Cu-Hf-Al-Be monolithic bulk amorphous alloy was developed utilizing minimal use of toxic and expensive Be. The developed alloy exhibits a large glass forming ability (GFA) (${\Phi}8$ mm). The possible mechanisms underlying the enhancement of the glass forming ability by this alloy are discussed based on the dimensionless parameter ${\gamma}$. In addition, alloy design strategy for the improvement of GFA is proposed in the viewpoint of heat of mixing (${\Delta}H_{mix}$)difference and atomic packing state.

• 대한전기학회논문지:전력기술부문A
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• 제48권2호
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• pp.127-135
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• 1999

Multivarialbe Boiler-Turbine H_\infty Control System Genetic Algorithm Weighting Functions $W_1$(s), $W_2$(s), and design parameter $\gamma$ that are given by Glover-Doyle algorithm, to optimally follow the output of reference model. The first method to do this is that the gains of weighting functions $W_1$(s), $W_2$(s), and design parameter are optimized simultaneously by genetic algorithm with the tournament method that can search more diversely, in the search domain which guarantees the robust stability of system. And the second method is that not only by genetic algorithm with the roulette-wheel method that can search more fast, in that search domain. The boiler-turbine H_\infty control system designed by theabove second method has not only the robust stability to a modeling error but also the the better command tracking preformance than those of the H_\infty control system designed by trial-and-error method and the above first method. Also, this boiler-turbine H_\infty control system has the better performance than that of the LQG/LTR contro lsystem. The effectiveness of this boiler-turbineH_\infty control system is verified by computer simulation.

• 한국지능시스템학회논문지
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• 제19권6호
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• pp.840-847
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• 2009

This paper deals with an $H_{\infty}$ output feedback controller design for uncertain singularly perturbed T-S fuzzy systems. Integral quadratic constraints are used to describe various kinds of uncertainties of the plant. It is shown that the $H_{\infty}$ norm of the uncertain singularly perturbed fuzzy system is less than $\gamma$ for a sufficiently small $\varepsilon$ > 0 if the $H_{\infty}$ norms of both the slow and fast subsystem are less than $\gamma$. Using this fact, we develop a linear matrix inequality based design method which is independent of the singular perturbation parameter $\varepsilon$. A numerical example is provided to demonstrate the efficacy of the proposed design method.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4102-4111
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• 2023

In order to better perform thermal hydraulic calculation and analysis of supercritical water reactor, based on the experimental data of supercritical water, the model training and predictive analysis of the heat transfer coefficient of supercritical water were carried out by using the support vector machine (SVM) algorithm. The changes in the prediction accuracy of the supercritical water heat transfer coefficient are analyzed by the changes of the regularization penalty parameter C, the slack variable epsilon and the Gaussian kernel function parameter gamma. The predicted value of the SVM model obtained after parameter optimization and the actual experimental test data are analyzed for data verification. The research results show that: the normalization of the data has a great influence on the prediction results. The slack variable has a relatively small influence on the accuracy change range of the predicted heat transfer coefficient. The change of gamma has the greatest impact on the accuracy of the heat transfer coefficient. Compared with the calculation results of traditional empirical formula methods, the trained algorithm model using SVM has smaller average error and standard deviations. Using the SVM trained algorithm model, the heat transfer coefficient of supercritical water can be effectively predicted and analyzed.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권4호
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• pp.220-224
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• 2014

A Bayesian zero-failure reliability demonstration test method for products with Weibull lifetime distribution is presented. Inverted gamma prior distribution for the scale parameter of the Weibull distribution is used to design the Bayesian test plan and selecting a prior distribution using a prior test information is discussed. A test procedure with zero-failure acceptance criterion is developed that guarantee specified reliability of a product with given confidence level. An example is provided to illustrate the use of the developed Bayesian reliability demonstration test method.