• IE interfaces
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• v.13 no.3
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• pp.539-547
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• 2000

An architecture of a Web-based Decision Support system for mathematical analysis is presented. Front-end modules provide web-client GUI environment for mathematical analysis. The networking architecture is built upon client/server system by Java socket and accesses database by JDBC in WWW. Back-end modules provide decision supporting service and data management for mathematical programming analysis. In the back-end any analysis tools, such as mathematical optimizer, simulation package, or statistics package can be used. As an application example for this implementation, optimal facility replacement decision problem is selected. In the implementation the optimal facility replacement decision problem is formulated as a shortest path problem. It uses Oracle DB and CPLEX package as the mathematical optimizer. While ORAWeb is designed and implemented on the optimal facility replacement problem, it can easily be extended to any decision supporting problems that would require mathematical optimization process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.538-543
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• 2011

In this paper, optimal spot weld layout design of the shock tower structure is performed for increasing fatigue life of spot weld and fatigue life of shock tower simultaneously. To predict the fatigue life, linear static analysis is conducted then fatigue analysis is performed by applying random vibration load. To optimize the spot weld layout, design variables that have an effect on spot weld fatigue life are selected. Based on the DOE table, spot weld fatigue analysis is conducted. Finally, response surface model is made from fatigue analysis results and optimized spot weld layout model which increases fatigue life of sport weld and fatigue life of shock tower is determined.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.170-179
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• 2007

This paper introduces the optimal disposition of direction finder using EM(Electro-magnetic) wave propagation analysis which is based on LR(Longley-Rice) propagation model and the characteristics of direction finder, emitter and terrain. Initial model is simulated and modified to minimize propagation error as a result of the field trials. Proposed analysis used line-of-sight analysis and mountain-top extraction algorithm to optimize the disposition in the assigned area and the result can be displayed in the 3D map in order of the percentage coverage for direction finding possibility area.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.345-352
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• 2014

In this paper, the CAD data for the optimal shape design obtained by isogeometric shape optimization is directly used to fabricate the specimen by using 3D printer for the experimental validation. In a conventional finite element method, the geometric approximation inherent in the mesh leads to the accuracy issue in response analysis and design sensitivity analysis. Furthermore, in the finite element based shape optimization, subsequent communication with CAD description is required in the design optimization process, which results in the loss of optimal design information during the communication. Isogeometric analysis method employs the same NURBS basis functions and control points used in CAD systems, which enables to use exact geometrical properties like normal vector and curvature information in the response analysis and design sensitivity analysis procedure. Also, it vastly simplify the design modification of complex geometries without communicating with the CAD description of geometry during design optimization process. Therefore, the information of optimal design and material volume is exactly reflected to fabricate the specimen for experimental validation. Through the design optimization examples of elasticity problem, it is experimentally shown that the optimal design has higher stiffness than the initial design. Also, the experimental results match very well with the numerical results. Using a non-contact optical 3D deformation measuring system for strain distribution, it is shown that the stress concentration is significantly alleviated in the optimal design compared with the initial design.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.353-359
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• 2009

This paper proposes a novel technique for calculating the security costs that properly includes ramping constraints in the operation of a deregulated power system. The ramping process is modeled by a piecewise linear function with certain assumptions. During this process, a ramping cost is incurred if the permissible limits are exceeded. The optimal production costs of the power producers are calculated with the ramping cost included, considering a time horizon with N-1 contingency cases using contingency constrained optimal power flow (CCOPF), which is solved by the primal-dual interior point method (PDIPM). A contingency analysis is also performed taking into account the severity index of transmission line outages and its sensitivity analysis. The results from an illustrative case study based on the IEEE 30-bus system are analyzed. One attractive feature of the proposed approach is that an optimal solution is more realistic than the conventional approach because it satisfies physical constraints, such as the ramping constraint.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.96-111
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• 1995

A bellows is a component installed in the automobile exhaust system to reduce the impact from an engine. It's stiffness has a great influence on the natural frequency of the system. Therefore, it must be designed to keep the specified stiffness that requires in the system. This study present the finite element analysis of U-typed bellows using a curved conical frustum element and the shape optimal design with specified stiffness. The finite element analysis is verified by comparing with the experimental results. In the shape optimal design, the weight is considered as the cost function. The specified stiffness from the system design is transformed to equality constraints. The formulation has inequality constraints imposed on the fatigue limit, the natural frequencies, the buckling load and the manufacturing conditions. A procedure for shape optimization adopts a thickness, a corrugation radius, and a length of annular plate as optimal design variables. The external loading conditions include the axial and lateral loads with a boundary condition fixed at an end of the bellows. The recursive quadratic programming algorithm is selected to solve the problem. The result are compared with the existing bellows, and the characteristics of the bellows is investigated through the optimal design process. The optimized shape of the bellows are expected to give quite a good guideline to the practical design.

• Korean Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.201-209
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• 1998

To develop timely an optimal fan, a design system and a new manufacturing process used step by step have to be integrated. A small sized optimal fan for refrigerators, that was the goal on this project, was developed by the following principal processes. All processes are technologically linked in many directions: The existing fan was measured through reverse engineering. The measured data was used for the basic source of 3D design. The performance tests were carried and used as the data for the evaluation of the existing fan. Flow analysis by FANS-3D/sup [1]/ was performed at the given information (pressure drop and flow rate) to find out the configuration of optimal fan design. The flow patterns were investigated to measure the performance of fan through numerical experiment. The grid point data obtained by the above analysis turned into 3D high efficiency fan model by using CATIA. The product was manufactured by RP process (SLS, SLA) and tested the characteristic curves of the developed fan to compare with the existing fan. The modification of fan design were all examined to see any change in performance and checked to find any deficiency in assembling the fan into a duct. After the plastics flow analysis of the injection molding cycle to ensure acceptable quality fan, an optimal mold was processed by using tool-path for the newly designed fan.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.987-994
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• 2008

The optimal structure of the Tonpilz transducer was designed. First, the FE model of the transducer was constructed, that included all the details of the transducer which used practical environment. The validity of the FE model was verified through the impedance analysis of the transducer. Second, the resonance frequency, the sound pressure, the bandwidth, and the impulsive shock pressure of the transducer in relation to its structural variables were analyzed. Third, the design method of $2^n$ experiments was employed to reduce the number of analysis cases, and through statistical multiple regression analysis of the results, the functional forms of the transducer performances that could consider the cross-coupled effects of the structural variables were derived. Based on the all results, the optimal geometry of the Tonpilz transducer that had the highest sound pressure level at the desired working environment was determined through the optimization with the SQP-PD method of a target function composed of the transducer performance. Furthermore, for the convenience of a user, the automatic process program making the optimal structure of the acoustic transducer automatically at a given target and a desired working environment was made. The developed method can reflect all the cross-coupled effects of multiple structural variables, and can be extended to the design of general acoustic transducers.

• Journal of Korean Society of Transportation
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• v.18 no.2
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• pp.91-101
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• 2000

The optimal congestion charge in transportation economics corresponds to the solution to the welfare maximization Problem for users of a certain road link where congestion takes Place. This congestion charge is in nature the optimal Price of the transportation facility, which is derived by the Partial equilibrium analysis on that facility. Therefore it is not certain that this congestion charge can maximize the well-being of all the users of the total transportation network, since the analysis does not count the impact of the congestion charge on traffic volumes of other links. This study suggests an alternative approach to estimate the optimal congestion charge. The key difference of this study from Previous ones is to derive the solution through the general equilibrium analysis on a market where several transportation facilities as well as Private goods are available to consumers. This approach shows a set of solutions a little different from the Previous one, which are explained below. The optimal congestion charge is derived for two different cases. One is the situation of which the congestion charge is levied on every transportation facility In this case, the optimal solution of each facility should equate the marginal utility of every user to the marginal cost of the corresponding facility. This analysis result in general equilibrium coincides with the Previous analysis result in partial equilibrium. However this result cannot apply to another case of which the charge is imposed only on a certain transportation facility. In this case, the optimal charge on a certain transportation facility should be less than the optimal congestion charge of partial equilibrium analysis.

• The KIPS Transactions:PartB
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• v.10B no.3
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• pp.311-320
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• 2003

The Optimal filter yielding optimal texture feature separation is a most effective technique for extracting the texture objects from multiple textures images. But, most optimal filter design approaches are restricted to the issue of supervised problems. No full-unsupervised method is based on the recognition of texture objects in image. We propose a novel approach that uses unsupervised learning schemes for efficient texture image analysis, and the band-pass feature of Gabor-filter is used for the optimal filter design. In our approach, the self-organizing neural network for multiple texture image identification is based on block-based clustering. The optimal frequency of Gabor-filter is turned to the optimal frequency of the distinct texture in frequency domain by analyzing the spatial frequency. In order to show the performance of the designed filters, after we have attempted to build a various texture images. The texture objects extraction is achieved by using the designed Gabor-filter. Our experimental results show that the performance of the system is very successful.