• Journal of Power System Engineering
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• v.8 no.1
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• pp.69-74
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• 2004

A structure-control combined optimal design problem is discussed taking a 3-D truss structure as a design object. We use descriptor forms for a controlled object and a generalized plant because the structural parameters appear naturally in these forms. We consider not only minimum weight design problem for structure system, but also suppression problem of the effect of disturbances for control system as the purpose of the design. A numerical example shows the validity of combined optimal design of structure and control systems. We also consider the validity of sensor-actuator collocation for control system design in this paper.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.4
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• pp.13-22
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• 1993

The aircraft scheduling, which is used to determine flight frequency, departure times and aircraft type assignments, is main problem of airline's planning. This paper proposes a new algorithm for aircraft scheduling that is to maximize airline profits. This paper proposes a column generation algorithm to get an optimal solution of the continous relaxation not using all the feasible variables, but using only a limited number of variables that is generated whenever it is necessary. Using this algorithm, proposes an optimal algorithm to get an optimal integer solution of aircraft scheduling problem efficiently. The effectiveness of the column generation algorithm and the optimal algorithm is illustrated by the computational results obtained from a series of real airline problems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.68 no.1
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• pp.129-139
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• 2019

In order for a gun-launched guided projectile to glide to the maximum range, when to deploy the fin and start flight with guidance and control should be considered in range optimization process. This study suggests a solution to the optimal guidance problem for flight range maximization of the flight model of a guided projectile in vertical plane considering the aerodynamic properties. After converting the nonlinear Multi-Phase Optimal Control Problem to Two-Point Boundary Value Problem, the optimized guidance command and the best fin deployment timing are calculated by the proposed numerical method. The optimization results of the multiple flight rounds with various initial velocity and launch angle indicate that determining specific launch condition incorporated with the guidance scheme is of importance in terms of mechanical energy consumption.

• Journal of the Korean Mathematical Society
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• v.36 no.1
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• pp.173-192
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• 1999

We study a boundary optimal control problem of the fluid flow governed by the Navier-Stokes equations. the control problem is formulated with the flow through a channel with steps. The first-order optimality condition of the optimal control is derived. Finite element approximations of the solutions of the optimality system are defined and optimal error estimates are derived. finally, we present some numerical results.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.578-583
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• 1992

In this paper, we show that various navigation constant values in PNG law can result in as optimal gains when we introduce proper time-varying weighting functions into the cost function of an optimal control problem. we then apply this idea to the guidance problem where we are required to achieve a given impact angle as well as the zero miss distance. As a result, we obtain a set of optimal guidance laws each of which could be related to a navigation constant in PNG. Some basic properties of these guidance laws are also presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.141-145
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• 2000

A systematic method to find the optimal blank shape for sheet forming is proposed by coupling the numerical simulation technique. A weighted parameter was introduced in order to simplify the multi-variable optimization problem to a single-variable problem. The proposed method has been applied to the blank design of drawing processes to obtain the near-net shape within the required error bound after forming, Excellent results have been obtained between the numerical results and the target contour shapes. Through the investigation the proposed systematic method for optimal blank design is found to be effective in the practical forming processes

• Management Science and Financial Engineering
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• v.22 no.1
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• pp.13-20
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• 2016

We investigate the optimal consumption and investment problem when a working debtor has an option to file for bankruptcy. By applying the duality approach, the closed-form solutions are obtained for the case of CRRA utility function. The optimal bankruptcy time is determined by the first hitting time when the financial wealth hits the wealth threshold derived from the optimal stopping time problem. Moreover, the numerical results show that the investment increases as the wealth approaches the threshold and the value gain from the bankruptcy option is vanished as wealth increases.

• 전기의세계
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• v.26 no.6
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• pp.66-71
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• 1977

In this paper a method is presented for the optimal control of a nuclear reactor at equilibrium state by use of a digital computer. Using the optimal control theory, we formulate the control problem of the reactor as a discrete-time linear regulator problem. A quadratic performance index is defined. The effects of choosing different performance index weighting matrices to the feedback gain matrix and reactor transient responses are studied for the deterministic optimal control with all state variables accessible to measurement.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.134-141
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• 2022

Transportation in urban area has been getting hard to fulfill the demand on time. There are various uncertainties and obstacles related with road conditions, traffic congestions, and accidents to interrupt the on-time deliveries. With this situation, the last mile logistics has been a keen issue for researchers and practitioners to find the best strategy of the problem. A way to resolve the problem is to use parcel lockers. Parcel locker is a storage that customers can pick up their products. Transportation vehicles deliver the products to parcel lockers instead of all customer sites. Using the parcel lockers, the total delivery costs can be reduced. However, the inconvenience of customer has to increase. Thus, we have to optimal solution to balance between the total delivery costs and customers' inconvenience. This paper formulates a mathematical model to find the optimal solution for the vehicle routing problem and the location problem of parcel lockers. Experimental results provide the viability to find optimal strategy for the routing problem as well as the location problem.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.25-29
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• 2003

LQ actuator selection problem for multi-input system discussed in this paper is to determine optimal actuator out of many actuators and input sequences so as to minimize the quadratic control performance. The solution of this problem depends on initial values and has a combinatorial property, so it is extremely difficult to get an optimal solution. For this difficulty, we proposed the concept of comparability of actuators and showed the uniqueness of the solution[1] . Further, to get general optimal solution for LQ problem with actuator selection strategies, we derived the equivalent condition for the comparability of actuator in single-input system . In this paper we extend this result to the case of multi-input system. The derived sufficient condition is applicable in the case of positive semi-definite comparability matrices.