• 경영과학
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• 제24권2호
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• pp.143-155
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• 2007

The purpose of this paper is to develop a new method for information system sizing and selection based on a hybrid mixture of simulation and genetic algorithm, and to show its cost-effectiveness by applying it to a real world problem. To serve this purpose, we propose an operational model which identifies a set of system alternatives using simulation, and determines the optimal one using genetic algorithm. Specifically, with simulation, we generate probability distributions describing real data gathered from actual system, which can overcome the major weakness of the existing methodology that normally employs point estimates of the actual data and constant correction factors without theoretical rationale. We next search for the optimal combination of H/W, the number of CPUs, and S/W, which meets both of our business goals of incurring low TCO(total cost of ownership) and maintaining a good level of transaction processing performance. Experimental result shows the proposed method in this paper saves the cost while it preserves the system's capacity within allowable performance range.

• 대한인간공학회지
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• 제23권3호
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• pp.25-38
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• 2004

Selection of a key dimension (s) by considering the characteristics of hand dimensions is needed to design gloves and construct a sound sizing system for gloves The present study identified key dimensions of glove design by analyzing the relationships between hand dimensions and demonstrated the construction process of a glove sizing system. By conducting correlation and regression analyses on 70 hand dimensions including 3 key dimension candidates (hand length; hand circumference; hand breadth) with the 1988 US Army data, hand length and hand circumference were selected as key dimensions for glove design. Glove sizing systems were constructed for males and females by applying the selected key dimensions, 0.5 inch of sizing intervals, and 2％ of presence rate criterion to the US Army data. This study suggests that glove sizing systems for males and females be very different from each other and a glove sizing system for males include more sizes than that for females.

• Journal of Electrical Engineering and Technology
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• 제11권3호
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• pp.551-559
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• 2016

The present trend of increasing the penetration levels of Distributed Generator (DG) in the distribution network has made the issue of Islanding crucial for the reliable operation of the network. The islanding, if not detected early may lead to the collapse of the system as it can drive the distribution system to the cascaded failure. In this paper, an extensive study of the effect of DG placement and sizing is performed by dividing the system into different zones to obtain a reduced effect of islanding. The siting and sizing of DG is carried out to improve the overall voltage profile or/and reduction in active power loss using two stage Genetic Algorithm (GA). In the first stage a basic knockout selection is considered and the best population is taken for next stage, where roulette selection for crossover and mutation is performed for optimal placement and sizing of DGs. The effect of the islanding, due to load variations is reduced by optimal siting and sizing of DG. The effectiveness of the proposed scheme is tested on the IEEE 33 and 69 radial bus systems and the results obtained are promising.

• 항공우주기술
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• 제11권1호
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• pp.1-6
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• 2012

인공위성의 전력 시스템을 보호하기 위해서 퓨즈나 LCL (Latching Current Limiter) 등을 부하와 전원 공급 장치 사이에 연결한다. 본 논문에서는 인공위성에서 장착되는 퓨즈의 용량 선정 기법에 대해 논하였다. 퓨즈 용량 선정 방법에 대해 기술하였고, 병렬 (Parallel) 퓨즈 연결 방식을 수학식으로도 단일 (Single) 퓨즈 연결 방식으로 나타낼 수 있음을 보였다. 또한, 퓨즈에 연결되는 부하의 정확한 전류 특성이 알려지지 않은 상태에서 적절한 퓨즈 선정 기법을 새롭게 제시하였다.

• 한국의류산업학회지
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• 제20권4호
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• pp.464-473
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• 2018

The objective of this study is to develop a sizing system of fitness clothing that can properly accommodate various body sizes of Korean senior women. The sizing system of upper and lower fitness clothing was developed in the present study by selection of key variables, identification of size category candidates, and determination of an optimal sizing system. First, key anthropometric dimensions (stature and bust circumference for upper clothing and stature; waist circumference for lower clothing) were identified by factor analysis on the direct body measurements (n = 272) and 3D whole-body scan data (n = 271) of Korean senior women in Size Korea. Second, sizing system candidates based on the key dimensions of upper and lower clothing were explored using a grid method and an optimization method. Lastly, among the sizing system candidates, optimal sizing systems of upper and lower clothing were selected in terms of accommodation rate. Five size categories (short/small, short/medium, tall/small, tall/medium, and tall/large) were selected as the optimal sizing systems of upper and lower clothing with 89% and 78% of accommodation rate, respectively, for the Korean senior women. The anthropometric characteristics of the representative humans of the optimal size categories would be of use in the design of fitness compressive wear for the better fit and effectiveness of exercise and health of Korean senior women.

• 한국의류산업학회지
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• 제16권5호
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• pp.766-775
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• 2014

This study is aimed to research the actual wearing condition of ballet dancewear of girls aged between 2 and 6 years on its design, size and fit. Survey data were collected from 171 mothers who have a girl learning ballet dance. The questionnaire was composed with ballet education, ballet dancewear purchasing, preference on design, size selection, and fitting. The collected data were analyzed with frequencies statistics, ${\chi}^2$-test, ANOVA using the SPSS WIN 20.0. The results are as follows; High rate of respondents said that the purpose of ballet education was for good body balance, leisure activity, and height growth. The main method of purchase was online shopping. The design, price, size and fit were identified as important ballet dancewear attributes for girls. The most preferred style of ballet dancewear were 'short sleeve skirted leotard' and 'camisole skirted leotard' which look like dress. The respondents reported slight satisfaction with size and fit, price, convenience in action, sewing and durability. The most preferred sizing system was code by height but any ballet dancewear makers don't use code by height. Therefore it is difficult for consumers to select size. Retailers and manufacturers could potentially use the results of this study to improve the sizing system and fit for children's ballet dancewear.

• 한국압력기기공학회 논문집
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• 제4권2호
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• pp.1-6
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• 2008

Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. A co-axial double-tube primary hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the VHTR. In this study, a preliminary design analysis for the primary HGD of the nuclear hydrogen system was carried out. These preliminary design activities include a determination of the size, a strength evaluation and an appropriate material selection. The determination of the size was undertaken based on various engineering concepts, such as a constant flow velocity model, a constant flow rate model, a constant hydraulic head model, and finally a heat balanced model.

• 대한기계학회논문집A
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• 제33권10호
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• pp.1108-1118
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• 2009

A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

• 항공우주기술
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• 제1권2호
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• pp.57-65
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• 2002

위성의 전력시스템은 임무기간 동안, 성공적인 임무수행을 위하여 위성의 탑재체와 위성버스에 충분한 전력을 공급하여야 한다. 전력시스템의 설계는 위성이 임무를 수행할 우주환경, 임무기간, 임무특성, 그리고 할당된 예산 등에 따라 설계의 방향이 결정된다. 즉, 1차 전력원으로 사용할 태양전지의 선정, 2차 전력원인 배터리의 선정, 그리고 각 전장품의 사양이 임무특성과 예산에 따라 결정된다. 위성의 전력시스템 설계는 다른 시스템의 설계에 큰 영향을 미칠 수 있다. 보다 많은 전력을 공급하기 위하여, 일차 및 이차 전력원을 크게 설계하는 것은 바람직하지 못하다. 위성의 필요한 전력보다 크게 설계된 전력시스템은 1차 및 2차 전력원의 잉여전력에 따른 열 발생문제, 임무수행에 따른 자세제어 문제, 각 전장품의 전력 용량 문제, 그리고 발사체의 선정 및 발사비용 등의 문제를 일으킨다. 특히, 저궤도의 경우에는 orbit drag 현상에 따른 위성의 궤도 유지보수를 위하여 추진제의 용량설계에 큰 영향을 줄 수 있다. 따라서, 전력시스템의 최적설계와 효율적인 운용을 위한 여러 기술이 개발되고 있다.

• 한국의류산업학회지
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• 제14권2호
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• pp.286-293
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• 2012

The purpose of this study was conducted to provide basic information on developing highschool-uniform pants with more suitable fit. To carry out this study, questionnaires were administered to 187 students in high schools in Gwangju. The collected data were analyzed with frequencies statistics, t-test, ANOVA using the SPSS WIN 18.0. The results are as follows; As results of research on highschool-uniform regulation, 88% of the highschool in Gwangju allowed their students to wear school uniform pants. As results of investigation on the school-uniform pants sizing system of manufacturing firm, it was found that there's a trend towards increasing a large size with the change body type. The size labelling for school uniform pants was waist circumference-stature. There were differences in pants sizes according to the manufacturing firm and body measurements such as hip circumference, in seam length, pants length. As results of survey on wearing conditions, the selection of school uniform pants has increased in winter season. The most important body measurement in the choice of purchase was thigh circumference. In fit of uniform pants, respondents answered that waist circumference and hip circumference became smaller according to the physical growth.