• Proceedings of the KSR Conference
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• 2005.05a
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• pp.453-458
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• 2005

Weight minimization of double-deck train carbody is imperative to reduce cost and extend life-time of train. It is required to decide 36 thickness of aluminum extruded panels. However, the design variables are two many to tract. moreover, one execution of structural analysis of double-deck carbody is time-consuming. Therefore, we adopt approximation technique to save computational cost of optimization process. Response surface model is used to apporximate static response of double-deck carbody. To obtain plausible response surface model, orthogonal array is empolyed as design of experiment(DOE). Design improvement by approximate model-based optimization is described. Accuracy and efficiency of optimization by using response surface model are discussed.

• Proceedings of the Korea Society for Simulation Conference
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• 1992.10a
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• pp.8-8
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• 1992

Through a simulation experiment, often an experimenter is concerned with estimating the system parameters of the linear model consisting of m design points from the outputs oft the simulation model. To improve the estimation of the system parameters and reliability of these estimators, appropriate simulation techniques have been developed. For the first order linear model, Schruben and Margolin (1978) exploited the random number assignment rules which uses a combination of common random numbers and antithetic streams in a simulation experiment designed to estimate the system parameters when the design matrix of simulation model admits orthogonal blocking into two blocks. Nozari, Arnold and Pegden (1984) developed a method for appliying the method of control variates to the situation of the linear model having multiple design points. This talk deals with a different way of utilizing controls under the correlation induction strategy of Schruben and Margolin's to improve the simulation efficiency, and presents a procedure for obtaining the estimators of the system parameters analytically. Simulation results on a selected simulation model indicate a promising evidence that a proposed method may yield better results than Schruben and Margolin's method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.630-639
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• 1998

The present research aimed at development of a computer code for the optimal design of ventilation system based on one-dimensional analysis of the air flow. Model experiment and three-dimensional flow analysis have been implemented to determine loss coefficients that were needed for the optimization technique. A research on optimum shape of ventilation shaft has been also carried out through the three-dimensional analysis of the flow.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.77-80
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• 1997

In this paper presented is a temperature controller for a semiconductor test handler. Using ARMAX model and least square method, the chamber model for the design of a controller is identified through experiment. With the identified model an LQG/LTR controller is designed. Experiment with a real test handler demonstrated good performance in that its overshoot is small and response time is fast.

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.187-196
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• 2021

The paper deals with comparative study for characteristics of approximation of design space according to various approximate models and sensitivity analysis using orthogonal array experiments in structure design of active type DSF which was developed for float-over installation of offshore plant. This study aims to propose the orthogonal array experiments based design methodology which is able to efficiently explore an optimum design case and to generate the accurate approximate model. Thickness sizes of main structure member were applied to the design factors, and output responses were considered structure weight and strength performances. Quantitative effects on the output responses for each design factor were evaluated using the orthogonal array experiment. Best design case was also identified to improve the structure design with weight minimization. From the orthogonal array experiment results, various approximate models such as response surface model, Kriging model, Chebyshev orthogonal polynomial model, and radial basis function based neural network model were generated. The experiment results from orthogonal array method were validated by the approximate modeling results. It was found that the radial basis function based neural network model among the approximate models was able to approximate the design space of the active type DSF with the highest accuracy.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.385-389
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• 2003

Three-dimensional experimental analysis was conducted in the pulverizer simplified isothermal model. The experiment model was constructed on a 1/3.5 scale of 500MW pulverizer. The purpose of this study is to investigate the effect of design parameters on the pulverized coal separator efficiency. Where used pulverized coal separator design parameters are guide vane angle, static classifier angle, dynamic classifier rpm. Taguchi method was used to find the effective design parameters related to pulverized coal separator efficiency. The results of the experiment showed that guide vane angle and dynamic classifier rpm were the design key parameters. In addition to the total number of experiment cases were reduced by Taguchi method.

• The Journal of Information Technology and Database
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• v.6 no.2
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• pp.45-57
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• 1999

This paper makes an attempt to find a systematic portion of the database design process, especially using the Entity-Relationship(E-R) model. Basically, we consider three aspects as a systematic portion of the database design process. They are, the strategy that a designer selects to design an E-R diagram, designer's cognitive style, and the knowledge and preference of the database designer. An experiment has been carried out in order to verify the systematic relationship between above-mentioned three aspects and the E-R modeling performance. The target system is a professional baseball system. A normative E-R diagram was constructed based upon 48 E-R diagrams produced during the experiment. The ANOVA process has been used to analyze the results. It has been found that there exist significant differences in query-answering capacity and the completeness of the E-R model among design methods. Individual differences in cognitive styles has not been found to be significantly related to the modeling performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.787-793
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• 2006

Recently kriging model has been widely used in the DACE (Design and Analysis of Computer Experiment) because of prominent predictability of nonlinear response. Since DACE has no random or measurement errors contrast to physical experiment, space filling experimental design that distributes uniformly design points over whole design space should be employed as a sampling method. In this paper, we examine the maximum entropy experimental design that reveals the space filling strategy in which defines the maximum entropy based on Gaussian or exponential. The influence of these two correlation functions on space filling design and their model parameters are investigated. Based on the exploration of numerous numerical tests, enhanced maximum entropy design based on exponential correlation function is suggested.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.51-59
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• 2017

In the early design stage of underwater vehicles, it is important to estimate the vehicle's underwater motion performance. The key design elements for the motion are propellers, battery power, and underwater resistance of the vehicle. Small thrusters with motor and propeller are usually used for the UUV(unmanned underwater vehicles). In this study, a multiphysics thruster model combining electro-mechanical and hydrodynamics characteristics was proposed to estimate the thruster performance. To show the applicability of the mathematical model, an sample thruster was used for the derive the unknown parameters of thruster. Hydrodynamic parameters were calculated for a 3D geometry model of the propeller by ANSYS/CFX program. Finally, Matlab/simulink program was used for the numerical simulation to predict the thruster performance from the given voltage/current input to the motor. Also, proved validity of simulation model by experiment test. Test were done by 2 mode(middle/high speed, reverse). The thruster performance curves obtained from this simulation were confirmed to be similar with experiment results.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1818-1822
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• 2008

Generally, not only in order to design three dimensional hydraulic structures such a spillway and to investigate the hydraulic phenomena concerning hydraulic facilities, but also to grasp shape and stability, we simulate actuality phenomenon through hydraulic model experiments. However, it requires too much times, expense and space to perform hydraulic model experiments, as well as it is very difficult to measure reduced scale of actual hydraulic structures. Besides, surface tension can exert fair effect in experiment result, and occasionally an experiment of various case is impossible actually. Therefore, there is necessity to draw proper early result through numerical analysis, and if decide the case of a hydraulic model experiment through the numerical analysis and compare the result, finally economical and reasonable design hydraulic structures are available. This study performs numerical analysis of overflow spillway and an experimental study of hydraulic model tests to design the optimal spillway and suggest a better design to improve hydraulic conditions. From the measurements, revised designs for an hydraulic structure are suggested and consequent improvement effects by the new design are also investigated.