• Journal of the Korean Society of Industry Convergence
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• v.12 no.1
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• pp.35-42
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• 2009

In Taguchi's quadratic expected loss function used as robustness metric of performance characteristics, the mean and variance contributions are confounded. The consolidation of the mean and variance in the expected loss function may not always be the ideal approach. This paper presents a procedure for multi-attributes design optimization, where the mean and variance of performance characteristics are considered as separate attributes having designer's relative preferences for them and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) is introduced to attain robust optimal design. The effectiveness of proposed approach is shown with an example of a weld line minimization problem in the injection molding process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.129-138
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• 1999

The aim of this research is the development of an automated fixture planning system for prismatic parts using the case-based reasoning (CBR). CBR is the problem solving paradigm that uses the similarity between a new problem and old cases to solve the new problem. This research uses CBR for the fixture planning. A case is composed with the information of the part, the components of fixture and the method of fixing for the part. The basic procedure is the retrieval and adaptation for the case, and this research presents the method of retrieval that selects most similar case to the new situation. The retrieval-step is divided into an index matching and an aggregated matching. The adaptation is accomplished by the modification, which transforms the selected case to the solution of the situation of the input part by the specified CBR algorithm. The components of fixture and the method of fixing are determined for a new part by the procedure.

• The Pure and Applied Mathematics
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• v.6 no.2
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• pp.113-120
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• 1999

This paper studies the problem of an infinite confined aquifer which at time t ＜ 0 is assumed motionless. At time t = 0 crude oil seeps into the aquifer, thereby contaminating the valuable drinking water. Since the crude oil and water are im-miscible, the problem is posed as a one-dimensional two-phase unsteady moving boundary problem. A similarity solution is developed in which the moving front parameter is obtained by Newton-Ralphson iteration. A numerical scheme, involving the front tracking method, is devised employing the fourth order Runge-Kutta method. Comparison of the exact and numerical schemes shows an error of only 3%. Thus the developed numerical scheme is quite accurate in tackling more realistic problems where exact solutions are not possible.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.2
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• pp.56-62
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• 2005

In this study, we first define user requirements to fulfill the reconnaissance and the search missions, by analyzing the system characteristics and operation environment. By investigating the design technology level, the development and procurement costs, the strong system design concepts and possible alternatives will be proposed. To analyze the system requirements, the Quality Function Deployment of the systems engineering approach will be implemented. The promising design alternatives that satisfy the user requirements are extracted by constructing the Morphological Matrix, then the best design concept will be obtained using the Pugh Concept Selection Matrix and the TOPSIS(Technique of Order Preference by Similarity to Ideal Solution).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.991-997
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• 2003

A flow field around a disc in an optical disc drive is invested using numerical methods. The high-speed rotating disc induces a strong flow field around the disc, which causes the pressure distribution on the surfaces of the disc. The pressure difference between the upper and the lower surfaces causes the deformation of the disc. In the first part of this study, flow fields around a rotating disc and a stationary wall are investigated using a similarity solution method, in order to identify the effect of the distance between the disc and the wall on the pressure distribution on the surfaces of the disc. In the second part, flow field in a slim-type optical disc drive is studied using a commercial code in order to consider the effect of the vortices generated by the local geometry of the drive.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.4
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• pp.215-221
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• 1991

Laminar film condensation of a saturated vapor in forced flow over a flat plate is analyzed by using integral method. Laminar condensate film is so thin that the inertia and thermal convection terms in liquid flow can be neglected. Approximate solutions for water are presented and well agreed with the similarity solutions over the wide range of physical parameter, Cp1(Ts-Tw)/Pr.hfg. For the strong condensation case, it is found that magnitude of the interfacial shear stress at the liquid-vapor interphase boundary is approximately equal to the momentum transferred by condensation, i.e., ${\tau}_i{\simeq}\dot{m}(U_O-U_i)$.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.555-567
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• 2014

Biometric performance improvement is a challenging task. In this paper, a hierarchical strategy fusion based on multimodal biometric system is presented. This strategy relies on a combination of several biometric traits using a multi-level biometric fusion hierarchy. The multi-level biometric fusion includes a pre-classification fusion with optimal feature selection and a post-classification fusion that is based on the similarity of the maximum of matching scores. The proposed solution enhances biometric recognition performances based on suitable feature selection and reduction, such as principal component analysis (PCA) and linear discriminant analysis (LDA), as much as not all of the feature vectors components support the performance improvement degree.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.587-592
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• 2000

The optimization method based on an enhanced genetic algorithms is proposed for multimodal function optimization in this paper. This method is consisted of two main steps. The first step is global search step using the genetic algorithm(GA) and function assurance criterion(FAC). The belonging of an population to initial solution group is decided according to the FAC. The second step is to decide the similarity between individuals, and to research the optimum solutions by simplex method in reconstructive search space. Two numerical examples are also presented in this paper to comparing with conventional methods.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.241-241
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• 2016

최근 기후변화로 인한 극한강우현상의 강도가 증가함에 따라 유출량과 첨두유량이 급격하게 증가하고 도달시간이 짧아지고 있어 홍수에 대한 피해가 증가하고 있다. 이와 더불어 도심지에서는 불투수면적 비율이 늘어나 수문순환에 큰 영향을 보이고 있다. 특히, 우리나라는 도시지역에 인구의 91.58%가 거주하고 있음에 따라 도시집중현상이 나타나고 있어 도심지의 홍수피해는 더욱 심각한 상황이다. 이에 본 연구에서는 서울의 청계천 유역을 대상으로 도시홍수 위험도 분석을 실시한다. SWMM을 이용하여 청계천 유역을 구성하고 소유역으로 나누어 재현기간에 따른 유출량에 대한 분석을 실시하고, 홍수 피해에 영향을 줄 수 있는 인문, 사회적인 자료를 수집한다. 소유역별로 수집된 자료를 바탕으로 TOPSIS(Technique for Order of Preference by Similarity to Ideal Solution)을 통해 도시홍수에 대한 위험도 분석을 실시하였다.

• Journal of Korea Multimedia Society
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• v.21 no.12
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• pp.1467-1472
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• 2018

For the problem that the face image of surveillance video cannot be accurately identified due to the low resolution, this paper proposes a low resolution face recognition solution based on convolutional neural network model. Convolutional Neural Networks (CNN) model for multi-scale input The CNN model for multi-scale input is an improvement over the existing "two-step method" in which low-resolution images are up-sampled using a simple bi-cubic interpolation method. Then, the up sampled image and the high-resolution image are mixed as a model training sample. The CNN model learns the common feature space of the high- and low-resolution images, and then measures the feature similarity through the cosine distance. Finally, the recognition result is given. The experiments on the CMU PIE and Extended Yale B datasets show that the accuracy of the model is better than other comparison methods. Compared with the CMDA_BGE algorithm with the highest recognition rate, the accuracy rate is 2.5%~9.9%.