• Proceedings of the Korean Statistical Society Conference
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• 2003.05a
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• pp.203-206
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• 2003

This paper studies constrained optimization of an M/G/1 queue with a server that can be switched on and off. One criterion is an average number of customers in the system and another criterion is an average operating cost per unit time, where operating costs consist of switching and running costs. With the help of queueing theory, we solve the problems of optimization of one of these criteria under a constraint for another one.

• Bulletin of the Korean Mathematical Society
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• v.45 no.3
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• pp.563-571
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• 2008

We deduce the necessary conditions for the optimality of endpoint constrained optimal control problem. These conditions comprise the adjoint equation, the maximum principle and the transversality condition. We assume that the cost function is merely differentiable. Therefore the technique under Lipschitz continuity hypothesis is not directly applicable. We introduce Fermat's rule and value function technique to obtain the results.

• Journal of applied mathematics & informatics
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• v.28 no.3_4
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• pp.823-835
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• 2010

In this paper, A FSQP algorithm for degenerate inequality constraints optimization problems is proposed. At each iteration of the proposed algorithm, a feasible direction of descent is obtained by solving a quadratic programming subproblem. To overcome the Maratos effect, a higher-order correction direction is obtained by solving another quadratic programming subproblem. The algorithm is proved to be globally convergent and superlinearly convergent under some mild conditions. Finally, some preliminary numerical results are reported.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.27-34
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• 2007

Static or dynamic elastomeric O-ring seals are installed between joining parts, and play key roles of high pressure-tightening. Sealing performance and structural safety of the O-ring are dependent on groove design, plain diameter, squeeze and applications such as pressure and temperature. In this study, to solve O-ring problem squeezed and highly pressurized under laterally one-sided constrained condition, hyperelastic FE analyses are performed, and FE results are compared with measured ones by computer-aided tomography, deformed shape and extrusion depth of the O-ring. Through the comparisons, FE analysis technique was verified. In order to evaluate design sensitivity, Taguchi method was used to select FE analysis cases. Adjustment parameters are clearance gap, groove comer radius, plain diameter and squeeze. By means of verified FE analysis technique, it has been analysed how the parameters have effects on contact stress fields, internal stress fields, and extrusion depths. Sealing performance has been evaluated based on contact stress fields and contact widths, and structural safety on internal stress and strain, extrusion lengths.

• Architectural research
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• v.9 no.1
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• pp.39-45
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• 2007

The static behavior of continuous system is described by the elastic curve method or is approximately analyzed by a finite element method to be modeled as a discrete system. If a continuous system is constrained by linear constraints which restrict its static behavior, its behavior can be approximately described by the finite element method. It is not easy to describe the constrained behavior by continuous coordinate system. Starting from the generalized inverse method provided by Eun, Lee and Chung, this study is to expand the equation to the continuous systems, to perform the structural analysis of the beam under a uniform loading with interior spring supports, and to investigate the validity of the proposed method through applications.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.672-681
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• 2000

Based on the dynamic anti-windup strategy a novel control methodology for state constrained control systems is presented. First a linear controller is designed for an open-loop stable plant to show a desirable nominal performance by ignoring state constraints. And then an additional dynamic compensator is introduced to preserve the nominal performance as closely as possible int he face of state constraints. This paper focuses on the second step under the assumption that a linear controller has already been designed appropriately by using an effective controller design method. By minimizing a reasonable performance index the dynamic compensator is derived explicitly which is expressed int he plant and controller parameters. the proposed method not only guarantees the total stability of the overall resulting systems but also provides desirable output performance because it solves the state-positioning problem completely.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.5
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• pp.511-520
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• 1999

An anti-reset windup (ARW) based compensation method for state constrained control systems is studied. First, a linear controller is constructed to give a desirable nominal performance ignoring state-constraints of a plant. Then, an additional compensator is introduced to provide smooth performance degradation under state-constraints of the plant. This paper focuses on the effective design method of the additional compensator. By minimizing a reasonable performance index, the proposed compensator is expressed in terms of theplant and ocntroller parameters. The resulting dynamics of the compensated controller exhibits the dominant part of the linear closed-loop system which can be seen from the singular perturbation model reducton theory. THe proposed method guarantees total stability of overall resulting systems if linear controllers were constructed to meet certain condition.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2076-2080
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• 2005

Study in this paper concerns the optimal $H_{2}$ integral servo problems for linear crane model systems via the constraints of the derivatives of state variables added to the standard constraints. It is shown in the paper that the derivative state constrained optimal $H_{2}$ integral servo problems can be reduced to the standard optimal $H_{2}$ control problem. The main subject of the paper is to apply the results of derivative state constrained $H_{2}$ integral servo theorem in crane system. The effect of our proposed controller with respect to mitigate an under damping for crane model system is also verified.

• Journal of the Korean Statistical Society
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• v.24 no.2
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• pp.453-470
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• 1995

We describe a constrained optimal classification rule for the case when the prior probability of an observation belonging to one of the two populations is unknown. This is done by suggesting a balanced design for the classification experiment and constructing the optimal rule under the balanced design condition. The rule si characterized by a constrained minimization of total risk of misclassification; the constraint of the rule is constructed by the process of equation between Kullback-Leibler's directed divergence measures obtained from the two population conditional densities. The efficacy of the suggested rule is examined through two-group normal classification. This indicates that, in case little is known about the relative population sizes, dramatic gains in accuracy of classification result can be achieved.

• Communications for Statistical Applications and Methods
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• v.14 no.3
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• pp.531-540
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• 2007

When multiple objectives exist, there are three approaches exist. These are maximin design, compound design, and constrained design. Still, each of three design criteria has its own strength and weakness. In this paper Hybrid approach is suggested when multiple design objectives exist, which is a combination of maximin and constrained design. Sometimes experimenter has several objectives, but he/she has only one or two primary objectives, others less important. A new approach should be useful under this condition. The genetic algorithm is used for few examples. It has been proven to be a very useful technique for this complex situation. Conclusion follows.