• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2006년도 춘계 학술대회 개요집
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• pp.304-306
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• 2006

Positioning the workpiece accurately and preventing the weld distortion, tack welding is often performed before main welding in the construction of welded structures. The weld bead size of the tack weld is determined according to the workpiece thickness, weld length, weld joint type etc. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually adopted for the uniform weld bead profile. In this study, an experimental method for the selection of optimal welding condition was proposed in the fillet weld which was done over the tack weld. This method uses the response surface analysis in which the leg length and the reinforcement height of weld bead were chosen as the quality variables of weld bead profile. The overall desirability function, which was combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. From the result, it was revealed that a uniform weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

• Molecules and Cells
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• 제26권1호
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• pp.1-4
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• 2008

A gene's influence on an organism's Darwinian fitness ultimately determines whether it will be lost, maintained or modified by natural selection, yet biologists have few gene expression systems in which to measure whole-organism gene function. In the Department of Molecular Ecology at the Max Planck Institute for Chemical Ecology we are training "molecularly enabled field biologists" to use transformed plants silenced in the expression of environmentally regulated genes and the plant's native habitats as "laboratories." Research done in these natural laboratories will, we hope, increase our understanding of the function of genes at the level of the organism. Examples of the role of threonine deaminase and RNA-directed RNA polymerases illustrate the process.

• 시스템엔지니어링학술지
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• 제1권2호
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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).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1205-1223
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• 2018

Image enhancement is an emerging method for analyzing the images clearer for interpretation and analysis in the spatial domain. The goal of image enhancement is to serve an input image so that the resultant image is more suited to the particular application. In this paper, a novel method is proposed based on Mamdani fuzzy inference system (FIS) using multiple fuzzy membership functions. It is observed that the shape of membership function while converting the input image into the fuzzy domain is the essential important selection. Then, a set of fuzzy If-Then rule base in fuzzy domain gives the best result in image contrast enhancement. Based on a different combination of membership function shapes, a best predictive solution can be determined which can be suitable for different types of the input image as per application requirements. Our result analysis shows that the quality attributes such as PSNR, Index of Fuzziness (IOF) parameters give different performances with a selection of numbers and different sized membership function in the fuzzy domain. To get more insight, an optimization algorithm is proposed to identify the best combination of the fuzzy membership function for best image contrast enhancement.

• 한국정밀공학회지
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• 제14권12호
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• pp.24-29
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• 1997

Recently, Genetic Algorithm(GA), which is a stochastic direct search strategy that mimics the process of genetic evolution, is widely adapted into a search procedure for structural optimization. Contrast to traditional optimal design techniques which use design sensitivity analysis results, GA is very simple in their algorithms and there is no need of continuity of functions(or functionals) any more in GA. So, they can be easily applicable to wide area of design optimization problems. Also, owing to multi-point search procedure, they have higher porbability of convergence to global optimum compared to traditional techniques which take one-point search method. The methods consist of three genetics opera- tions named selection, crossover and mutation. In this study, a method of finding the omtimum size and topology of drilling machine is proposed by using the GA, For rapid converge to optimum, elitist survival model,roulette wheel selection with limited candidates, and multi-point shuffle cross-over method are adapted. And pseudo object function, which is the combined form of object function and penalty function, is used to include constraints into fitness function. GA shows good results of weight reducing effect and convergency in optimal design of drilling machine.

• 한국의류학회지
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• 제37권4호
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• pp.526-539
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• 2013

This study analyzed the effects of internet fashion consumer's anticipated regret and the selection difficulty on decision making delay and purchase switching intention. The survey was conducted in 2012 on internet fashion consumers in their 20s to 40s from May 1 to June 30; subsequently, 487 responses were used for the data analysis. The anticipated regret of internet fashion consumers was composed of product, service, social psychology, and function-related anticipated regret. The selection difficulty of internet fashion consumers was composed of process, information, and experience-related selection difficulty. There are significant differences in anticipated regret, selection difficulty, decision making delay, and purchase switching intention by gender. The anticipated regret (product, service, and social psychology-related anticipated regret) and selection difficulty effected decision making delay. In addition, the anticipated regret for product and selection difficulty by process or information influenced purchase switching intention. The results of this study provide useful information on the success and efficient operation of internet shopping malls.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.4776-4798
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• 2015

The location selection of virtual machines in distributed cloud is difficult because of the physical resource distribution, allocation of multi-dimensional resources, and resource unit cost. In this study, we propose a multi-object virtual machine location selection algorithm (MOVMLSA) based on group information, doubly linked list structure and genetic algorithm. On the basis of the collaboration of multi-dimensional resources, a fitness function is designed using fuzzy logic control parameters, which can be used to optimize search space solutions. In the location selection process, an orderly information code based on group and resource information can be generated by adopting the memory mechanism of biological immune systems. This approach, along with the dominant elite strategy, enables the updating of the population. The tournament selection method is used to optimize the operator mechanisms of the single-point crossover and X-point mutation during the population selection. Such a method can be used to obtain an optimal solution for the rapid location selection of virtual machines. Experimental results show that the proposed algorithm is effective in reducing the number of used physical machines and in improving the resource utilization of physical machines. The algorithm improves the utilization degree of multi-dimensional resource synergy and reduces the comprehensive unit cost of resources.

• Communications for Statistical Applications and Methods
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• 제7권2호
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• pp.617-631
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• 2000

This paper is concerned with suggesting a Bayesian method for variable selection in generalized logit model. It is based on Laplace-Metropolis algorithm intended to propose a simple method for estimating the marginal likelihood of the model. The algorithm then leads to a criterion for the selection of variables. The criterion is to find a subset of variables that maximizes the marginal likelihood of the model and it is seen to be a Bayes rule in a sense that it minimizes the risk of the variable selection under 0-1 loss function. Based upon two examples, the suggested method is illustrated and compared with existing frequentist methods.

• 대한전자공학회논문지
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• 제17권2호
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• pp.1-9
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• 1980

채널튜닝전압 자체를 기억시키는 종래의 전압합성방식을 개선, 10키이를 통하여 입력시킨 채널번호에 의해 튜닝전압을 계산하여 VHF 및 UHF 전대역에 실제채널번호를 표시하면서 직접접근선국(direct access channel selection)할 수 있는 회로를 설계하였다. 또한 본 회로는 택안(search)에 의한 미세튜닝 및 방송이 없을 경우의 표시를 자동적으로 행하며, 2개의 키이로 채널 전반을 순차적으로 선국할 수 있는 기능도 가지게 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.1006-1010
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• 1995

This paper describes Sexual Reproduction Genetic Algorithm(SRGA) for function optimization. In SRGA, each individual utilize a diploid chromosome structure. Sex cells(gametes) are produced through artificial meiosis in which crossover and mutation occur. The proposed method has two selection operators, one, individual selection which selects the individual to fertilize, and the other, gamete selection which makes zygote for offspring production. We consider the effects of multi-selection and diploidy on search performance. SRGA improves local and global search(exploitation and exploration) and show optimum tracking performance in nonstationary environments. Gray coding is incorporated to transforming the search space and Genic uniform distribution method is proposed to alleviate the problem of premature convergence.