• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1999-2004
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• 2004

Collision avoidance for the aircraft can be stated as a problem of maintaining a safe distance between aircrafts in conflict. Optimal collision avoidance problem seeks to minimize the given cost function while simultaneously satisfying the constraints. The cost function can be a function of time or input. This paper addresses the trajectory time-optimization problem for collision avoidance of the unmanned aerial vehicles. The problem is difficult to handle, because it is a two points boundary value problem with dynamic environment. Some simplifying algorithms are used for application in on-line operation. Although there are more complicated problems, by prediction of conflict time and some assumptions, we changed a dynamic environment problem into a static one.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.11 s.254
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• pp.1479-1485
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• 2006

To minimize the leakage of microwave which can occur when one pulls the door of a microwave oven during its operation, shape optimization of the door frame is presented. A numerical optimization is implemented to minimize the dynamic twisting deformation of the door frame. Shape design variables are defined, which represent the dimension of the bead in the flange. Two optimal design problems are established to minimize the maximum twisting deformation from harmonic response analysis. The problems are solved, their results being compared and evaluated.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.7
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• pp.317-322
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• 2005

Advantages of switched reluctance motor(SRM) include a simple structure, the ability of operation in hash environments and under partial hardware failures, and a wide speed range. However design of SRM for industrial applications is very difficult because motor's inherent none-linearity and sensitivity of design parameter. In this paper, an optimal method for determining design parameters of a switched reluctance motor is researched. The dominant design parameters are stator and rotor pole arc and switching on and off angle. The parameters affecting performance are examined and selected using evolutionary computations and commercial CAD Program. The proposed design process is very fast. reliable and easy to access. The simulated design method proposed is compared with conventional procedure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.409-415
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• 2008

This paper proposed a new optimal design method of the electronic ballast with stable run-up current for Metal Halide lamp during the ignition condition. In order to avoid operation in the acoustic resonance frequency band and to supply the optimal ignition current without demage of inverter switching components during the ignition period, the values of the series inductor Ls, the series capacitor Cs, and the parallel capacitor Cp were determined by analysis of characteristics of inverter transfer function depend on Lamp operating power and resistance of ignition condition and steady state operating condition. For the prototype ballast for a 400W Metal Halide Lamp, experimental results are presented in order to validate the proposed method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.369-374
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• 2008

This paper presents the evaluation procedures and the estimation method for the estimation of optimal rebate level for EE(Energy Efficiency) programs. The penetration amount of each appliance is estimated by applying price function to preferred diffusion model resulted from model compatibility test. To estimate the optimal rebate level, two objective functions which express the maximum energy saving and operation benefit are introduced and by multi-objective function which can simultaneously consider two objective functions the optimal rebate level of each appliance is estimated. And then, using the decided rebate level and each penetration amount, the priority order for reasonable investment of each high-efficiency appliance is estimated compared to the results of conventional method. Finally, using a benefit/cost analysis based on California standard practice manual, the economic analysis is implemented for the four perspectives such as participant, ratepayer impact measure, program administrator cost and total resource cost.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.97-102
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• 2001

This paper is concerned with optimal design of a linear DC motor which is steading fast in OA and FA systems due to simplicity in structure high-speed operation and high-precision positioning. The approach is based on the statistic method. In this study, firstly, we determine factors that affect significantly the objective function using 2-level factorial design. And then the Response Surface Methodology was app1ied to optimize these factors. Through this application design factors could be optimized within a short term and low experimental cost.

• Communications of the Korean Mathematical Society
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• v.12 no.3
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• pp.531-538
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• 1997

In this paper, we show how to construct an optimal normal basis over finite field of high degree and compare two methods for fast operations in some finite field $GF(2^n)$. The first method is to use an optimal normal basis of $GF(2^n)$ over $GF(2)$. In case of n = st where s and t are relatively primes, the second method which regards the finite field $GF(2^n)$ as an extension field of $GF(2^s)$ and $GF(2^t)$ is to use an optimal normal basis of $GF(2^t)$ over $GF(2)$. In section 4, we tabulate implementation result of two methods.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1540-1546
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• 2017

In piezoelectric device applications, it is important to improve a system efficiency because of the low generated power. In this paper, an optimal driving method is proposed to improve a system efficiency for a piezoelectric energy harvesting system. The proposed method considers disappear energy in input capacitors and the converter efficiency according to the input voltage magnitude to minimize energy losses. Experimental results based on various energy generation cases verify that the proposed method significantly improves the system efficiency; the efficiency is approximately 9.97% higher than that of the conventional method.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.715-718
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• 2009

The assembly line is one of the typical process hard to analyze with mathematical methods including even stochastic approaches, because it includes many manual operations varying drastically depending on operators' skills. In this paper, we suggest the simulation optimization method to design the optimal assembly line of a gas oven. To achieve the optimal design, firstly, we modeled the real gas oven assembly line with actual data, such as assembly procedures, operation rules, and other input parameters and so on. Secondly, we build some alternatives to enhance the line performance based on business rules and other parameters. The DOE(Design Of Experiment) techniques were used for testing alternatives under various situations. Each alternatives performed optimization process with evolution strategy; one of the GA(Genetic Algorithm) techniques. As a result, we can make about 7% of throughputs up with the same time and cost. By this process, we expect the assembly line can obtain the solution compatible with their own problems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.57-60
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• 2003

As the business dependency to information systems and the frequency of the large scale disasters increase, implementing the disaster recovery center has been a common practice. However, since there has been little quantitative decision method for the distance between the data center and the disaster recovery center, the distance decision has been commonly made by qualitative guidelines. In this research, the decision method for the optimal distance between the data center and the disaster recovery center is developed, using the cost analysis including the operation cost and the expected disaster cost. An illustrative numerical example is provided.