• 대한전기학회논문지:전력기술부문A
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• 제54권9호
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• pp.457-460
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• 2005

This paper proposes a new Interior Point Method algorithm to improve the computation speed and solution stability, which have been challenging problems for employing the nonlinear Optimal Power Flow. The proposed algorithm is different from the tradition Interior Point Methods in that it adopts the Predictor-Corrector Method. It also accommodates the five minute dispatch, which is highly recommenced in modern electricity market. Finally, the efficiency and applicability of the proposed algorithm is demonstrated with a case study.

• Journal of applied mathematics & informatics
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• 제4권1호
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• pp.167-178
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• 1997

In this paper we present an application to airfoil design of an optimum design method based on optimal control theory. The method used here transforms the design problem by way of a change of variable into an optimal control problem for a distributed system with Neumann boundary control. This results in a set of variational inequalities which is solved by adding a penalty term to the differential equation. This si inturn solved by a finite element method.

• Journal of applied mathematics & informatics
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• 제30권1_2호
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• pp.1-14
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• 2012

In this paper, the problem of determining the optimal car-deriving strategy has been examined. In order to find the optimal driving strategy, we have modified a method based on measure theory. Further, we demonstrate that the modified method is an efficient and practical algorithm for dealing with optimal control problems in a canonical formulation.

• 제어로봇시스템학회논문지
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• 제18권12호
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• pp.1086-1089
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• 2012

We propose a near optimal controller design method for ramp metering based on SDRE (State Dependent Riccati Equation) approach. We parameterize the optimal nonlinear controller in terms of the solution matrices of an SDRE. We also give a simple algorithm to obtain the controller gain. Finally we give numerical results to show the effectiveness of the proposed near optimal traffic controller design method.

• 대한수학회지
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• 제47권1호
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• pp.83-100
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• 2010

In this article, an optimal control problem associated with convection-diffusion equation is considered. Using Lagrange multiplier, the optimality system is obtained. The derived optimal system becomes coupled, non-symmetric partial differential equations. For discretizations and implementations, the finite element multigrid V-cycle is employed. The convergence analysis of finite element multigrid methods for the derived optimal system is shown. Some numerical simulations are performed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권6호
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• pp.421-430
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• 2000

This paper describes an optimal design method which is applied a weighted least square (WLS) method for Magnetic Resonance Imaging (MRI) system. An optimal design approach is presented for a homogeneity superconducting magnet with the superconducting active shield especially for a magnetic resonance imaging system. The WLS is used to obtain the optimal configurations using the least amount and minimum volume of conductor, exhibiting the smallest level of field inhomogeneity and resulting in the least level of stray field. The proposed model is used to design a multiple-shield configuration for a 1.5 T MRI magnet. The field homogeneity is required less than 5 gauss stray field contour within 4m axially and 3m radially from origin. The designed magnet with the actively magnetic shielding coil out of main coils is analyzed by FEM and theoretical analysis method, investigated the field homogeneity.

• Journal of Magnetics
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• 제18권4호
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• pp.454-459
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• 2013

This paper deals with an optimal angle error reduction method of magnetic position sensor using hall effect elements. The angle detection simulation for the magnetic position sensor is performed by 3 dimensional finite element method and Taguchi method, one of the design of experiments. The magnetic position sensor is required to generate ideal sine and cosine waveforms from its hall effect elements according to rotation angle for precise angle information. However, the output signals are easy to include harmonics due to uneven magnetic field distribution from permanent magnet in the air-gap in the vicinity of hall effect elements. For the Taguchi method, three design parameters related to position of hall effect elements and shape of back yoke are selected. The characteristics of optimal magnetic position sensor are compared with those of original one in terms of simulation as well as experiment. Finally, the performances of the motor adopting original model and optimal model are represented for the purpose of verification of motor performance due to signals from magnetic position sensor.

• 한국컴퓨터산업학회논문지
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• 제2권9호
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• pp.1155-1162
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• 2001

본 논문은 UNIX 시스템의 최적 이용률(Optimal Utilization)을 결정하는 방법을 제시한다. 제시된 방법은 사용자가 인내할 수 있는 응답시간(Tolerable Response Time)을 제공하는 범위에서 사용자에게 허용될 수 있는 최대 이용률이 최적 이용률이 된다는 정의(Definition)를 근거로 하여 개발되었다. 인내할 수 있는 응답시간이 길어지면 최적 이용률도 높아지므로 최적 이용률은 인내할 수 있는 응답시간의 최대값에서 구해진다. 인내할 수 있는 응답시간은 서비스 목표(Service Objective)가 주어지면 도출해 낼 수 있다. 본 논문에서는 인내할 수 있는 응답시간이 0.24초라는 것과 최적 이용률의 세 가지 구성요소는 %wio, %sys, %usr 이라는 것을 보여준다. 또한 최적 이용률을 결정하는 실제의 과정을 예시하기 위하여 UNIX 운영체제를 사용하는 IBM 컴퓨터의 최적 이용률을 구하는 과정을 예시한다.

• 한국정보처리학회논문지
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• 제2권5호
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• pp.807-813
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• 1995

본 논문은 UNIX 시스템의 최적 이용율(Optimal Utilization)을 결정하는 방법을 제시한다. 제시된 방법은 사용자가 인내할 수 있는 응답시간(Tolerable Response Time) 을 제공하는 범위에서 사용자에게 허용될 수 있는 최대 이용율이 최적 이용율이 된다 는 정의(Definition)를 근거로하여 개발되었다. 인내할 수 있는 응답시간이 길어지면 최적 이용율도 높아지므로 최적 이용율은 인내할 수 있는 응답시간의 최대값에서 구해 진다. 인내할 수 있는 응답시간은 서비스 목표(Service Objective) 가 주어지면 도출 해낼 수 있다. 본 논문에서는 인내할 수 있는 응답시간이 0.24초라는 것과 최적 이용 율의 세가지 구성요소는 %wio, %sys, %usr이라는 것을 보여준다. 또한 최적 이용율을 결정하는 실제의 과정을 예시하기 위하여 UNIX 운영체제를 사용하는 IBM 3081 컴퓨터 의 최적 이용율을 구하는 과정을 보여준다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2528-2533
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• 2007

Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature..