• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.65-71
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• 2003

This research deals with how to select connection positions of two substructures to be synthesized. The goal of this research is to find optimal connection positions in order to maximize the fundamental natural frequency of the synthesized structure. The natural frequencies of a connected structure are obtained by modal-force equations. Optimal connection positions can be selected through optimization process. In the optimization process, the natural frequencies of a connected structure are set to object function value and connection positions become design variables. The method described above is applied to synthesis problems of plates, which is initially conducted for FE models and verified through experiments. Especially in experiments, FRE(frequency Response function)s are obtained by means of the Modal Testing technique to be used in modal-force equations for synthesizing. Once the substructures are synthesized, the Modal Testing technique is again applied to spot-welded structure using the result from the optimization procedure. It is found that the fundamental natural frequency of the synthesized structure with the optimized result gives higher value than those with the initially given connection positions.

• Journal of Welding and Joining
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• 제25권4호
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• pp.49-57
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• 2007

The optimization of the cladding parameters was studied to maximize the deposition efficiency in the laser cladding using a low power pulsed Nd:YAG laser. STS304 stainless steel plate and Co alloy powder were used as a substrate and powder for cladding, respectively. The six cladding parameters were selected through preliminary experiments and their effects on the deposition efficiency were analyzed statistically. Experiments were designed and carried out using the Taguchi experimental method using a L18 orthogonal array. It was found from the results of analysis of variance(ANOVA) that the powder feed position and powder feed angle had the most significant effects on the deposition efficiency, but the powder feed rate and laser focal position had nearly no effects. The deposition efficiency could be maximized at 0mm of the powder feed position and 50o of the powder feed angle in the experimental range. From this experimental analysis, a new laser cladding head with 20o of the powder feed angle was designed and manufactured. With a new laser cladding head, the highest deposition efficiency of 12.2% could be obtained.

• 한국추진공학회지
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• 제17권4호
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• pp.10-15
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• 2013

설계 최적화를 위해서 설계자는 우선적으로 설계영역 전반에 걸쳐 정확한 정보를 획득하고, 설계영역 탐색을 실시한 후에 최적화를 실시해야 한다. 최근에 설계영역 탐색을 우선적으로 실행하기 위하여 실험계획법과 반응표면모델에 최적화를 적용하는 통합설계 프레임워크의 적용이 산업체 전반으로 일반화되고 있다. 본 연구에서는 터보팬 엔진 설계점 최적화를 위하여, 설계영역의 정보를 조밀하게 얻을 수 있으며 통계학적인 직교성과 균형성을 모두 만족하는 7 수준 직교배열을 생성한 후에 반응표면모델을 구축한다. 구축된 반응표면모델에 전역 최적값을 찾기 위하여 다목적 유전자알고리즘을 적용하여 주어진 제한조건을 만족하는 최적값을 찾아 GasTurb 결과와 검증을 수행한다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.242-248
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• 2000

This paper has focused on the optimization of the cutting parameters for turning operation based on the Taguchi method. Four cutting parameters, namely, cutting speed, feed, depth of cut and nose radius are optimized with consideration of the surface roughness. The design and analysis of experiments are conducted to study the performance characteristic. The effects of these parameters on the surface roughness have been investigated using the signal-to-noise (S/N) ratio, analysis of variance (ANOVA). The experiments have been peformed using coated tungsten carbide inserts without any cutting fluid. Experimental results illustrate the effectiveness of this approach.

• 한국기계가공학회지
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• 제3권4호
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• pp.13-19
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• 2004

This paper deals with the analysis of geometric error and the optimization of process parameters in surface grinding. Taguchi method which is one of the design of experiments has been introduced in achieving the aims. The process parameters were the grain size, the wheel speed, the depth of cut and the table speed. The effect of the process parameters on the geometric error was examined and an optimal set of the parameters was selected to minimize the geometric error within the controllable range of the used grinding machine. The reliability of the results was evaluated by the ANOVA.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.17-22
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• 2019

The method of electrical discharge machining (EDM), one of the processing methods based on non-traditional manufacturing procedures, is gaining increased popularity, since it does not require cutting tools and allows machining involving hard, brittle, thin and complex geometry. This present investigation details the determination of optimum process parameter to attain the better machining performance in EDM of AISI 4340 steel with graphite as a tool electrode. The experimental combinations are planned and analyzed by Taguchi's design of experiments approach. To predict the optimal condition, the experiments are conducted by using Taguchi's L27 orthogonal array. The influence of process variables such as discharge current, pulse on and pulse off time, voltage and spark speed were investigated to control the various desired performance measures such as surface roughness. Analysis of Variance (ANOVA) has to be performed to know the magnitude of each factor. Investigations indicate that the surface roughness is strongly depend on pulsed current.

• 반도체디스플레이기술학회지
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• 제14권2호
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• pp.47-52
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• 2015

In this paper, the performance of uncoated- and Titanium nitride aluminium TiAlN-PVD coated- carbide twist drills were investigated when drilling aluminium alloy, Al 6061. This research focuses on the optimization of drilling parameters using the Taguchi technique to obtain minimum surface roughness and thrust force. A number of drilling experiments were conducted using the L9 orthogonal array on a CNC vertical machining center. The experiments were performed on Al 6061 material l blocks using uncoated and coated HSS twist drills under dry cutting conditions. Analysis of variance(ANOVA) was employed to determine the most significant control factors. The main objective is to find the important factors and combination of factors influence the machining process to achieve low surface roughness and low cutting thrust force. From the analysis of the Taguchi method indicates that among the all-significant parameters, feed rate are more significant influence on surface roughness and cutting thrust than spindle speed.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (2)
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• pp.697-699
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• 2004

Stochastic Neighbor Embedding(SNE) is a probabilistic method of mapping high-dimensional data space into a low-dimensional representation with preserving neighbor identities. Even though SNE shows several useful properties, the gradient-based naive SNE algorithm has a critical limitation that it is very slow to converge. To overcome this limitation, faster optimization methods should be considered by using trust region method we call this method fast TR SNE. Moreover, this paper presents a couple of useful optimization methods(i.e. conjugate gradient method and Newton's method) to embody fast SNE algorithm. We compared above three methods and conclude that TR-SNE is the best algorithm among them considering speed and stability. Finally, we show several visualizing experiments of TR-SNE to confirm its stability by experiments.

• 산업기술연구
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• 제22권A호
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• pp.83-87
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• 2002

Many industrial products such as paints, ink and adhesives are composed of the ingredients of a mixture. In mixture experiments, the characteristics of quality(response) depends only on the proportions of the ingredients and does not depend on the total amount of the mixture. This article discusses the constrained mixture experimental design, the data analysis, and the optimum formulation of ingredients based on the two quality characteristics - taste and flavor. It IS shown that efficient designs can be constructed from D-optimal criterion. Special cubic models were selected as the final mixture response surfaces for both reponses. The desirability function was used for the optimization of the two responses.

• 한국자동차공학회논문집
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• 제9권3호
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• pp.190-200
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• 2001

The homogenization method is applied to maximize crash energy absorption for a given volume. To obtain the best combination of optimizing factors by resizing and threshold algorithms for an example problem, the sensitivity analysis has been performed using design of experiments. The results show that very little interaction among optimizing factors is found. Optimization analysis of several combination of factors is conducted; and the orignal design and a new design with holes for an example problem are compared for crash energy absorption.