• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.313-318
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• 1994

It is well known that the neural network can be used as an universal approximater for functions and functionals. But these theoretical results are just an existence theorem and do not lead to decide the suitable network structure. This doubfulness whether a certain network can approximate a given function or not, brings about serious stability problems when it is used to identify a system. To overcome the stability problem, We suggest successive identification and control scheme with supervisory controller which always assures the identification process within a basin of attraction of one stable equilibrium point regardless of fittness of the network.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1992년도 춘계공동학술대회 발표논문 및 초록집; 울산대학교, 울산; 01월 02일 May 1992
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• pp.403-412
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• 1992

This note examines a situation where a risk-neutral insurer and a risk-averse individual (prospective insured) negotiate to reach an arbitration point of the price of insurance over the terms of an insurance contract in order to maximize their respective self-interests. The situation is modeled as a Nash bargaining problem. We analyze the dependence of the price of insurance, which is determined by the Nash solution, on the parameters such as the size of insured loss, the probability of a loss, the degree of risk-aversion of the insured, and the riskiness of loss distribution.

• 한국경영과학회지
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• 제11권2호
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• pp.7-12
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• 1986

The problem of strategic R & D investment is formulate as a differential game model and solved explicity for a special case. It is shown that, at equilibrium, an increase in the intensity of market competition or a decrease in the role of technology transfer results in an increase in the initial rate of investment by competing tfirms. The increased initial investment rate may enhance the rate of technology development. This dynamic model can be used to propose non cooperative R & D investment policies in technologically competitive situation.

• 응용통계연구
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• 제3권1호
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• pp.47-58
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• 1990

로보트화된 좌표측정기에 사용됨에 따라, 직교 회귀가 이제는 단순히 흥미로운 수학문제로 그치지 않게 되었다. 특히, 공학 전공 학생을 대상으로 하는 기초 통계학 과목에서 간단히나마 다룰만한 문제가 되었다고 본다. 직교 회귀의 핵심 개념을 간략히 정리한다. 아울러 직교 회귀의 기하학적 구조를 공학 전공 학생들이 잘 알고 있는 역학적 개념으로 설명함으로써 학생들이 쉽게 이해하고 또한 사고의 폭을 넓히는데 도움이 되고자 한다.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제3권2호
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• pp.99-112
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• 1999

In this paper, we represent the Piagetian reversible thinking by using the concept of fuzzy complements. In this case the turning point to the reversible thinking can be corre-sponded to the equilibrium points of a fuzzy set, which are shown through some examples. On the other hand, Piaget considered disequilibrium in the theory of equi-libration as a stimulus for students' cognitive structure, furthermore as the driving forces behind intellectual growth. But we suggest a di erent application o Piagetian equi-librium in another point of view as a tool understanding students' psychological stability in problem solving activity.

• 대한수학회지
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• 제35권1호
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• pp.135-148
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• 1998

We propose the new controls constructed via the second or direct method of Liapunov to solve the collision avoidance control problems for moving objects and a robot arm in the plane. We also explicate the controlling effect by the simulations.

• Journal of Mechanical Science and Technology
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• 제16권12호
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• pp.1687-1692
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• 2002

The problem analyzed here is a sheet metal forming process which requires a drawbead. The drawbead provides the sheet metal enough tension to be deformed plastically along the punch face and consequently, ensures a proper shape of final products by fixing the sheet to the die. Therefore, the optimum design of drawbead is indispensable in obtaining the desired formability. A static-explicit finite element analysis is carried out to provide a perspective tool for designing the drawbead. The finite element formulation is constructed from static equilibrium equation and takes into account the boundary condition that involves a proper contact condition. The deformation behavior of sheet material is formulated by the elastic-plastic constitutive equation. The finite element formulation has been solved based on an existing method that is called the static-explicit method. The main features of the static-explicit method are first that there is no convergence problem. Second, the problem of contact and friction is easily solved by application of very small time interval. During the analysis of drawbead processes, the strain distribution and the drawing force on drawbead can be analyzed. And the effects of bead shape and number of beads on sheet forming processes were investigated. The results of the static explicit analysis of drawbead processes show no convergence problem and comparatively accurate results even though severe high geometric and contact-friction nonlinearity. Moreover, the computational results of a static-explicit finite element analysis can supply very valuable information for designing the drawbead process in which the defects of final sheet product can be removed.

• 대한수학회보
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• 제47권4호
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• pp.675-685
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• 2010

In this paper, we consider a new class of regularized (nonconvex) generalized mixed variational inequality problems in real Hilbert space. We give the concepts of partially relaxed strongly mixed monotone and partially relaxed strongly $\theta$-pseudomonotone mappings, which are extension of the concepts given by Xia and Ding [19], Noor [13] and Kazmi et al. [9]. Further we use the auxiliary principle technique to suggest a two-step iterative algorithm for solving regularized (nonconvex) generalized mixed variational inequality problem. We prove that the convergence of the iterative algorithm requires only the continuity, partially relaxed strongly mixed monotonicity and partially relaxed strongly $\theta$-pseudomonotonicity. The theorems presented in this paper represent improvement and generalization of the previously known results for solving equilibrium problems and variational inequality problems involving the nonconvex (convex) sets, see for example Noor [13], Pang et al. [14], and Xia and Ding [19].

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1992년도 봄 학술발표회 논문집
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• pp.58-64
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• 1992

It is usual that underground structures are constructed within multi-layered medium. In this paper, an efficient numerical model ling of multi-layered structural systems is studied using coupled analysis of finite elements and boundary elements. The finite elements are applied to the area in which the material nonlinearity is dominated, and the boundary elements are applied to the far field area where the nonlinearity is relatively weak. In the boundary element model 1 ins of the multi-layered medium, fundamental solutions are restricted. Thus, methods which can utilize existing Kelvin and Melan solution are sought for the interior multi-layered domain problem and semi infinite domain problem. Interior domain problem which has piecewise homogeneous layers is analyzed using boundary elements with Kelvin solution; by discretizing each homogeneous subregion and applying compatibility and equilibrium conditions between interfaces. Semi-infinite domain problem is analyzed using boundary elements with Melan solution, by superposing unit stiffness matrices which are obtained for each layer by enemy method. Each methodology is verified by comparing its results which the results from the finite element analysis and it is concluded that coupled analysis using boundary elements and finite elements can be reasonable and efficient if the superposition technique is applied for the multi-layered semi-infinite domain problems.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.249-257
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• 2007

A high resolution numerical method aimed at solving gas-liquid two-phase flow is proposed and applied to gas-liquid two-phase shock tube problem. The present method employs a finite-difference 4th-order Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL TVD scheme. By applying the homogeneous equilibrium cavitation model, the present density-based numerical method permits simple treatment of the whole gas-liquid two-phase flow field, including wave propagation and large density changes. The speed of sound for gas-liquid two-phase media is derived on the basis of thermodynamic relations and compared with that by eigenvalues. By this method, a Riemann problem for Euler equations of one dimensional shock tube was computed. Numerical results such as detailed observations of shock and expansion wave propagations through the gas-liquid two-phase media and some data related to computational efficiency are made. Comparisons of predicted results and exact solutions are provided and discussed.