• 소성∙가공
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• 제15권2호
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• pp.153-157
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• 2006

In this study, the die design and die series on the surface residual stress of cold drawn eutectoid steel wire have been investigated. Test pieces were fabricated using die series with different mean and final reduction ratios. Surface residual stresses in the axial direction were measured by X-ray diffraction, Bruker's 2-dimensional GADDS system. The results were compared with stress profiles that were calculated by 3D and 2D finite element simulations, ABAQUS 6.4 program in finite element analysis(FEA). By means of the FEA method, optimal die shape considering delta-parameter were induced and applied in order to determine die sequence designs. Balance of the drawing stresses was also introduced to optimize die sequence.

• 한국의류학회지
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• 제11권3호
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• pp.89-99
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• 1987

The purpose of this present study is not only to investigate mutal relationship between the preference of clothing design and the nature of Reflectiveness-Impulsiveness, but to offer clothing design for desirably developing of child, especially of preschool children. And the practical research was performed for 166 preschool children who are in kindergarten located in Seoul and are selected according to their sex and social class. This study used Kagan's MFFT and Personality Inventory of Hwang Eung-Yeon for the test of Reflectiveness-Impulsiveness, while for the preference of clothing design used the photo deck which is showed to children. The data analysis was based on frequency, percentage, mean, standard deviation, chi-square ($x^2$) test, t-test, F-test, and Duncan's Multiple Range Test. It can be concluded that girls rather than toys, high class children rather than middle or low class children were more reflective as a general trend. The relationship between the preference of clothing design and the nature of Reflectiveness and Impulsiveness is as follows : 1. In color, reflective boy liked blue series and reflective girl liked pastel coloring series, while they disgusted red series and non-coloring series. The group of impulsiveness liked red series, while they disgusted non-coloring series. 2. In color combination, group of reflectiveness liked similar color, while group of impulsiveness liked contrasting color. 3. In texture, group of reflectiveness liked soft and shiny texture, while they disgusted thick and rough texture. Also Group of impulsiveness liked soft texture. 4. In pattern, reflective boy liked lettering pattern and reflective girl liked flower pattern, while she disgusted lettering pattern. Impulsive boy liked stripe pattern and limpulsive girl liked flower pattern. 5. In pattern size, group of reflectivenss liked small size, while group of impulsiveness liked large one. 6. In style, group of reflectiveness liked formal style.

• 대한전기학회논문지
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• 제37권6호
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• pp.376-382
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• 1988

A small-signal low-frequency disturbance of the input line affects the regulated-output voltage of the series resonant converter. To mitigate the detrimental effect, the output feedback PI-controller is employed. Small-signal linear models are represented to characterize the closed loop series resonant converter system. Design equations for the PI-controller which satisfy stability and percent ripple conditions are derived from the closed-loop linear model. Experimental results are presented which show excellent correlation with theory.

• 제어로봇시스템학회논문지
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• 제16권8호
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• pp.804-809
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• 2010

This paper proposes a Taylor-series design method which reduces the height error of the tag when readers are arranged at the same height in 3-dimensional space. The proposed method consists of two steps. Firstly, the planar position is estimated by the Taylor-series method using the TDOA measurement. Next, the height is estimated from the estimated planar position. In order to show the validity of the proposed method, computer simulations were performed for the static case and linear trajectory of the tag. Results show that the proposed method gives convergent estimated position and better height estimate than the Taylor series method.

• 대한두개안면성형외과학회지
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• 제13권1호
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• pp.1-3
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• 2012

The case series is a descriptive study that follows a group of patients who have a similar diagnosis or who are undergoing the same procedure and is the most prevalent type of research in the field of plastic surgery. Results of case series can generate hypotheses that are useful in designing further studies, including randomized controlled trials or a prospective cohort study. However, no causal inferences should be made from case series regarding the efficacy of the investigated treatment. The authors provide a guide to the design and report on the case series.

• Journal of Power Electronics
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• 제9권2호
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• pp.300-307
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• 2009

In this paper, design and control is proposed for a four input-series-output-series-connected ZVS full bridge converter for the photovoltaic power conditioning system (PCS). The novel topology for a photovoltaic (PV) DC/DC converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing PV module characteristics is proposed. The control scheme, including an input voltage controller is proposed to achieve equal sharing of the input voltage as well output voltages by a four series connected module. Design methods for ZVS power stage are also introduced. The total PV system is implemented for a 250-kW PV power conditioning system (PCS). This system has only three DC/DC converters with a 25-kW power rating and uses only one-third of the total PV PCS power. The 25-kW prototype PV DC/DC converter is introduced to verify experimentally the proposed topology. In addition, an experimental result shows that the proposed topology exhibits good performance.

• 대한전기학회논문지
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• 제45권4호
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• pp.517-525
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• 1996

A Simple AC complex circuit analysis for LCL type series resonant converter with phase shift control is proposed. Based on these analyses, a set of characteristic curves which allows a optimal design procedure for this converter is shown, without increasing the volt-ampere rating of tank circuit Especially, inverter output peak current can be minimized in both full load and partial load conditions. The presented design considerations can make the load range wide from full loads to light loads achieving turn-on with zero voltage switching (ZVS) operation. The detailed analysis and experimental results show the effectiveness of the proposed design algorithms. (author). refs., figs., tab.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 1998년도 가을 학술발표대회 논문집 디자인 학 연구
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• pp.46-47
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• 1998

• 대한토목학회논문집
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• 제34권2호
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• pp.469-478
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• 2014

확률수문량을 산정하기 위해서 실무에서 많이 사용하는 연최대치 계열은 자료의 구축이 간편한 장점이 있지만, 우리나라에서 연최대치 계열을 이용하기에는 자료의 수가 매우 제한적이다. 특히, 적은 관측자료를 바탕으로 확률강우량 또는 설계홍수량을 추정할 경우 과다산정을 할 가능성이 매우 높다. 본 연구에서는 기상청에서 제공하는 1973년부터 2012년까지 총 40년간의 관측자료를 대상으로 독립호우사상을 구분하고, 연최대치 계열과 비연초과치 계열을 구성한 후, 연최대치 계열과 비연초과치 계열로부터 산정된 확률강우량의 상관성을 분석하고, 적은 관측자료를 가지고 지점빈도해석을 수행하여 확률강우량을 추정할 수 있는 방법을 제안하였다.

• Journal of applied mathematics & informatics
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• 제5권2호
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• pp.277-284
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• 1998

The reliability and an estimate for it are derived for series-parallel and parallel-deries stress-strength model under assumption that all components are subjected to a common stress. We also obtain the asymptotic normal distribution of the estimate.