• Journal of KSNVE
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• v.10 no.3
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• pp.437-443
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• 2000

The optimal design problem for increasing dynamic stiffness using hybrid model which composed of original detailed BIW(body in white) and impinged beam elements is investigated. Using the characteristics of the beam elements and design sensitivity analysis this approach utilizes an optimization technique to determine the optimal section properties of beam elements. The constraint is to increase the first natural frequency by five percent compared with original one. The results show that the first torsion and bending natural frequencies are increased by five percent using hybrid model and optimization. These results indicate that this optimization method can be employed to enhance the dynamic stiffness of vehicle body structure in design concept stage.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.209-219
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• 2000

A method is developed to evaluate machining process and to determine the optimal machining conditions considering the environmental effects. The method Is based on the evaluation attributes from the general LCA programs and the analysis technique of AHP from HHS. To assist the analysis. the mass models of cutting energy, tools, and fluids are developed. The models may be used for both quantitative prediction of the uses and disposed masses of materials and optimization of the machining conditions. The algorithm with the mass models is applied to the milling process planning. The process to survey the environmental data, calculate the used mass, and evaluate the alternatives is demonstrated. This demonstration illustrates the of the change of process conditions of the decision making.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.2
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• pp.127-139
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• 1998

The objectives of this study is at the development of the channel routing model which can be used for flood prediction. Among the routing models, the hydraulic technique of the implicit scheme in the dynamic equation is selected to route the unsteady varied flow in the open channel. The channel routing model is catchment runoff which computed by the conceptual and transfer function model. The conceptual and transfer function model can simulate the catchment runoff accurately. As a result of investigating the channel routing model, the optimal weighting factor ${\theta}$ which fixes two points between time line is chosen, and also, the optimal error tolerance which satisfies computing time and converge of solution is determined in this study.

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.177-186
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• 2004

Decision analysis has becomes an important technique for decision making in the face of uncertainty. It is characterized by enumerating all the available courses of action, identifying the payoffs for all possible outcomes, and quantifying the subjective probabilities for the all possible random events. When the data are available, decision analysis becomes a powerful tool for determining an optimal course of action. We study the multi-attribute decision making in a compensatory models. In this paper, we use the entropy methods in weights calculating. For the purpose of making optimal decision, the data of five different car models are used. For computing, we used Visual Numerica Version 1.0 software package.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1307-1311
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• 2004

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. They can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. Especially in die design module an optimal design technique and horizontal split die were investigated for determining appropriate dimensions of components of multi-former die set. It is constructed that the proposed method can be beneficial for improving the tool life of die set at practice.

• The Korean Journal of Ecology
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• v.8 no.3
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• pp.147-152
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• 1985

The forest vegetation of natural reserve area (175ha) at north-eastern slope of Solibong (537m), Gwangneung, was studied by plant sociological method and two dimensional ordination technique. In the area dominated by Carpinus laxiflora, from the lower site to peak of Solibong, a zonal distribution of C. laxiflora-Quercus mongolic forest, C. laxiflora-C. cordata forest, C. laxiflora-Q. serrata forest, C. laxiflora forest and C. laxiflora-Rhododendron schlippenbachii forest were recognized by the plant sociological survey. It is seem that the optimal range of Carpinus laxiflora forest occur in mesic-warm site by two dimensiional ordination with thermal condition and soil moisture condition. The optimal range (over 100 in importance value) was the range of 76~89。C.month in warmth index and 18~45% in soil water content.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.162-164
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• 1994

This paper presents the optimal design method of an induction motor for electric vehicle which minimizes the weight of motor and satisfies maximum power rating at the same time. Effects of motor parameters on the dimensions and weight of motor is investigated. Optimal routine which is used in this paper is simulated annealing technique.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.321-322
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• 2008

Co-optimization of Gen. Speed Governor & AGC are essential to control proper Frequency control & Economic Dispatch. Improper AGC Control result in the decrease of Electricity frequency quality & Generator Life cycle by over-regulating each Generator. This paper presents a number of AGC Area/PLC parameter tuning technique & better performance results. This optimal tuning was studied & implemented by System Operation Dept Korea Power Exchange in 2007.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.345-347
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• 2008

Available transfer capability(ATC) is an important indicator of the usable amount of transmission capacity accessible by several parties for commercial trading in power transaction activities. This paper deals with an application of optimization technique for available transfer capability(ATC) calculation and analyzes the results of ATC by using several variables of optimal power flow. The method proposed is applied to the modified IEEE 14 buses model system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.825-830
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• 2006

Capacity-approaching codes using iterative decoding have been the main subject of research activities during past decade. Especially, LDPC codes show the best asymptotic performance and density evolution has been used as a powerful technique to analyze and design good LDPC codes. In this paper, we apply density evolution with a Gaussian approximation to the concatenated zigzag (CZZ) codes by considering both flooding and two-way schedulings. Based on this density evolution analysis, the threshold values are computed for various CZZ codes and the optimal structure of CZZ codes for various code rates are obtained. Also, simulation results are provided to conform the analytical results.