• 한국지반공학회논문집
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• 제19권1호
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• pp.221-228
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• 2003

해성점토를 이용한 준설매립공사에 있어서 준설매립 지반의 자중압밀현상을 예측하기 위해 준설점토의 간극비-유효응력-투수계수의 관계인 구성관계 산정은 가장 중요한 사항이다. 그러나 준설매립 지반은 고함수비의 재료특성으로 인해 실험을 통한 구성관계의 산정에 많은 어려움이 발생하게 된다. 이를 위해 저응력 압밀시험기 등을 이용한 실험을 통해 산정하고자 하는 연구들이 진행되고 있다. 본 연구에서는 저응력 압밀시험기를 이용하여 구성관계를 산정하였고, 저응력 압밀시험기를 이용한 실험시 많은 시간이 소요되는 단점을 극복하고자 준설점토를 이용한 컬럼실험에서 얻어진 변수들을 바탕으로 초연약 준설매립점토의 구성관계를 산정할 수 있는 산정식에 대한 연구를 실시하였다 저응력 압밀 및 투수실험을 통해 준설점토의 구성관계를 파악할 수 있었고, 또한 침강 및 자중압밀 실험결과를 이용하는 구성관계 산정식을 통해 저응력 단계에 대한 구성관계를 얻을 수 있었으며, 저응력 압밀시험에서 얻어진 결과와의 연속성을 확인할 수 있었다. 따라서 본 연구의 산정식을 이용하여 간편하게 구성관계를 파악할 수 있었다. 본 연구의 구성관계 산정식을 이용하여 준설매립지반의 자중압밀현상을 예측에 이용할 수 있으리라고 판단된다.

• Journal of Forest and Environmental Science
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• 제33권4호
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• pp.305-314
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• 2017

This study aimed to predict changes in forest area using a probability density function, in order to promote effective forest management in the area north of the civilian control line (known as the Minbuk area) in Korea. Time series analysis (2010 and 2016) of forest area using land cover maps and accessibility expressed by distance covariates (distance from buildings, roads, and civilian control line) was applied to a probability density function. In order to estimate the probability density function, mean and variance were calculated using three methods: area weight (AW), area rate weight (ARW), and sample area change rate weight (SRW). Forest area increases in regions with lower accessibility (i.e., greater distance) from buildings and roads, but no relationship with accessibility from the civilian control line was found. Estimation of forest area change using different distance covariates shows that SRW using distance from buildings provides the most accurate estimation, with around 0.98-fold difference from actual forest area change, and performs well in a Chi-Square test. Furthermore, estimation of forest area until 2028 using SRW and distance from buildings most closely replicates patterns of actual forest area changes, suggesting that estimation of future change could be possible using this method. The method allows investigation of the current status of land cover in the Minbuk area, as well as predictions of future changes in forest area that could be utilized in forest management planning and policymaking in the northern area.

• Journal of the Korean Data and Information Science Society
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• 제12권2호
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• pp.1-10
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• 2001

신경망은 점차 분류 및 함수추정을 위한 현대 통계적 방법론으로 부각되고 있다. 신경망은 특히 선형 회귀함수를 일반화시키는 유연한(flexible) 방법을 제공하며 일반적 비선형 함수를 모수화하는 방법으로 간주된다. 본 논문에서는 함수추정을 위한 신경망을 생각한다. 신경망이 훈련자료를 과대적합하는 것을 피할 수 있도록 하는 간단한 방법은 정칙화(regularization)이다. 신경망에서는 정칙화를 위해 주로 가중치 감소법(weight decay method)을 사용한다. 함수추정을 위해 가중치감소 신경망을 사용할 때 은닉노드수, 가중치모수, 학습률 및 학습반복회수가 중요한 모수이다. 본 논문에서는 유전자 알고리즘을 사용하여 가중치감소 신경망의 중요한 모수들을 자동으로 최적화하는 방법을 제안하고 결과적으로 가중치감소 신경망을 자동학습하는 방법을 설명한다. 그리고 다른 함수추정방법들과 자동학습된 가중치감소 신경망을 비교분석한다.

• Environmental Analysis Health and Toxicology
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• 제2권1_2호
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• pp.43-53
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• 1987

Among the environmental toxic metals, cadmium and lead compounds are very hazard for human health because these may affect the biological function of human body and furthermore enhance the cause of various disease. In recent years, as the view of environmental toxicology, the combination of toxic metals suffering human health is especially significant cadmium chloride (10 mg/kg P. 0., 1 mg/kg I.P.) and lead acetate (20 mg/kg P.O., 2 mg/kg I.P.) were administered to rats for 4 weeks on alternate days and then examined the effect of these on body weight, tissue weight and also biochemical function in blood and tissue were investigated and comparision of the two experimental groups such as single and combined administration. According to the results of this experiment, accumulation of heavy metals increased and biological metabolic function grew worse but, in tissue, toxic effect decreased by combined administration and intraperitoneal administration was more toxic than per OS.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.122-130
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• 2001

In this paper, an operational algorithm for a 2-shaft parallel hybrid electric vehicle is suggested for the minimization of operation cost. The operation cost is obtained as a summation of the engine fuel cost and the motor electricity cost. The electrical cost function is estimated in case of motoring, and generating when the recuperation is carried out during the braking. In addition, weight function is introduced in order to maintain the battery state of charge. Based on the operation algorithm, the optimal engine operation point that minimizes the operation cost is obtained with respect to the required vehicle power for every state of charge of battery. The optimal operation point provides the optimal power distribution of the engine and the motor for a required vehicle power Simulation was performed and the fuel economy of the hybrid vehicle was compared to that of the conventional vehicle. Simulation results showed that hybrid vehicle's fuel economy can be improved as much as 45∼48% compared to the conventional vehicle's.

• 대한수학회보
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• 제54권6호
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• pp.2155-2163
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• 2017

Zwegers showed that a mock theta function can be completed to form essentially a real analytic modular form of weight 1/2 by adding a period integral of a certain weight 3/2 unary theta series. This theta series is related to the holomorphic modular form called the shadow of the mock theta function. In this paper, we discuss the computation of shadows of the second order mock theta functions and show that they share the same shadow with a mock theta function which appears in the Mathieu moonshine phenomenon.

• 제어로봇시스템학회논문지
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• 제2권3호
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• pp.142-147
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• 1996

In this paper, we describe the algorithm which controls an unknown nonlinear system with multilayer neural network. The multilayer neural network can be used to approximate any continuous function to any desired degree of accuracy. With the former fact, we approximate unknown nonlinear function on the nonlinear system by using of multilayer neural network. The weight-update rule of multilayer neural network is derived to satisfy Lyapunov stability. The whole control system constitutes controller using feedback linearization method. The weight of neural network which is used to implement nonlinear function is updated by the derived update-rule. The proposed control algorithm is verified through computer simulation.

• 산업경영시스템학회지
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• 제25권4호
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• pp.40-45
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• 2002

An AS/RS construction cost minimization model under throughput rate requirement constraint has been developed, whose objective function includes S/R machine cost, storage rack cost, and interrace conveyor cost. S/R machine cost is a function of the storage rack height, the unit load weight, and the control logic used by the system, while storage rack cost is a function of the storage rack height, the weight and the volume of the unit load. Since the model is a nonlinear integer programming problem which is very hard to solve exactly with large problem size, a solution procedure is developed to determine the height and the length of the storage rack with a fixed number of S/R machines, while increasing the number of S/R machines one by one to meet the throughput rate requirement.

• Communications for Statistical Applications and Methods
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• 제1권1호
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• pp.27-32
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• 1994

We propose a robust regression estimator which has both a high breakdown point and a bounded influence function. The main contribution of this article is to present a weight function in the generalized M (GM)-estimator. The weighting schemes which control leverage points only without considering residuals cannot be efficient, since control leverage points only without considering residuals cannot be efficient, since these schemes inevitably downweight some good leverage points. In this paper we propose a weight function which depends both on design points and residuals, so as not to downweight good leverage points. Some motivating illustrations are also given.

• Journal of applied mathematics & informatics
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• 제29권3_4호
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• pp.547-562
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• 2011

We establish a new formalism of the non-periodic autocorrelation function (NPAF) of two sequences, which is suitable for the computation of the NPAF of any two sequences. It is shown, that this encoding of NPAF is efficient for sequences of small weight. In particular, the check for two sequences of length n having weight w to have zero NPAF can be decided in $O(n+w^2{\log}w)$. For n > w^2{\log}w$, the complexity is O(n) thus we cannot expect asymptotically faster algorithms.