• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.840-845
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• 2001

Development of a small gas-turbine combustor for 100kW class APU(Auxiliary Power Unit) has been performed. This combustor is a reverse-annular type and has a tangential swirler in the liner head to improve the fuel/air mixing and flame stability. Three main and three pilot fuel injectors of the simplex pressure-swirl type are used. The performance target at the design condition includes a turbine inlet temperature of 1170K, a combustion efficiency of 99%, a pattern factor of 30%, and an engine durability of 3000 hours. Under developing the combustor, we conducted performance test of our first prototype(TS1) with some variants. As a result of the test, the performance targets of the combustor are satisfied except that the pattern factor is about 4% higher than target value. So, we redesigned the second prototype(TS2) and conduct performance test with the critical focus on pattern factor and exit mean temperature. We adopted TS2 four variant to check the improvement of pattern factor. As the result, the pattern factors of several variants were satisfied with the performance target. Finally, We chose the TS2A variant as a final combustor for our APU model.

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.69-81
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• 2020

The objective of this study is to seek ways to maximize learning effects from e-learning by drawing improvement directions through investigating and analyzing an awareness of e-learning among e-learning attendees. The study was conducted among the attendees who are taking the e-learning program operated by K University and collected data from the students taking second semester in 2018 with the use of structured questionnaires. For data processing, SPSS Statistics 22.0 and AMOS were used, along with such analytical methods as frequency anslysis, descriptive statistical analysis, ANOVA (Analysis of Variance), t-analysis and cross tabulation. For significant data, it conducted an analysis by carrying out the Scheffe's test. According to the findings from this study, they showed a significant difference only in gender and curriculum desired to be opened in the question about e-learning participation motives per background factor. As for the learners' motives to study, it was confirmed that they tend to become more biased on time utilization and convenience of learning methods. The analysis of which factor of the three - learning factors, system factors and instructor's factors - has greatest effects on learning satisfaction indicated that learning factors influenced learning satisfaction the most in accordance with values for non-standard coefficient beta, followed by instructor factors which had a direct effect.

• 조명전기설비학회논문지
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• 제18권5호
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• pp.83-89
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• 2004

최근 전력계통의 대형화와 중조류 설비의 증가 등으로 계통내부에서 소모되는 무효전력 급증에 따라 계통전압관리차원에서 부하역률 관리의 중요성이 새롭게 대두되고 있다. 따라서 본 논문에서는 최소자승법(Least Square Method)을 이용하여 변압기 무효전력 손실량을 산출하였으며, 유량평균법(Average Flow Method)을 사용하여 부하특성에 따른 지역별, 계절별, 시간대별 부하역률 대표모델을 수립하였다.

• Journal of Power Electronics
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• 제11권1호
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• pp.37-44
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• 2011

In this paper, a four-phase 8/6-pole 4-kW SR motor drive model is presented. Based on experimental data, the model allows an accurate simulation of a drive in dynamic operation. Simulations are performed and a laboratory type set-up is built based on a TI TMS320F2812 platform to experimentally verify the theoretical results obtained for a SR motor. To reduce acoustic noise and to correct the power factor of this drive, a two-stage power converter is proposed that uses a current source rectifier (CSR) as the input stage for the asymmetrical converter of the studied SRM. Employing the space-vector modulation (SVM) method in matrix converters, the CSR switching allows the dc link's capacitors to be eliminated and the power factor of the SRM drive to be improved. As the electrical motive force (emf) is directly proportional to the rotor speed, the input voltage to the machine can be programmed to be a function of the speed with the modulation index of the CSR, leading to a reduction in the acoustic noise of the SRM drive. Simulation of the whole SRM drive system is performed using MATLAB-Simulink. The results fully comply with the required conditions such as power factor correction with an improvement in the THD.

• 스마트미디어저널
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• 제7권1호
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• pp.24-30
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• 2018

제노테크(주)는 NFC기반 2 factor 전자결제시스템의 보안기능 향상을 위해 FIDO인증기술을 이전받았으며 이를 활용하여 새로운 서비스인 갤러리-옥션을 개발하였고 대구 전시회에서 데모 시연을 진행하였다. 시연 결과 배너 제작 및 설치, UI변경, 동작 순서 변경 등의 개선 요구 사항이 있었으며 요구 사항을 바탕으로 갤러리-옥션을 개선하였다. 이후 개선된 갤러리-옥션의 2차 데모시연을 '아트:광주:17'에서 진행하였고 동시에 '아트:광주:17'의 시간당 입장객 수를 분석 및 시각화를 수행하였다.

• 콘크리트학회논문집
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• 제14권4호
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• pp.474-482
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• 2002

본 연구의 목적은 섬유의 부착시험을 통하여 섬유의 파괴없이 최대 인발저항을 가지고 시멘트 모체 내에서 완전한 정착작용을하는 구조용 합성섬유의 최적형상과 최적형상함수를 도출하는데 있다. 7가지 다른 형상의 구조용 합성섬유를 조사하였고 부착시험을 수행하였다. 부착시험의 변수는 7가지의 다른 형상이고, 2종류의 시멘트 모르타르의 배합이다. 부착시험 결과, 7가지 다른 형상중 crimped type이 계면인성(인발에너지)와 인발하중에서 가장 우수한 성능을 보였다. Crimped type을 기본으로 하여 섬유의 주기와 높이를 바꾸어 부착시험을 실시한 결과 최적형상함수, D= $b^{{\alpha}ο{\alpha}}$ $h^{λ{\beta}}$ 를 도출하였다.

• 대한가정학회지
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• 제41권6호
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• pp.119-129
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• 2003

This study was peformed to establish the standard size system to be required for the production of brassiere. The subject were 155 Korean twenties-aged women and were directly measured anthropometrically. From 27 measurements, 5 factors were extracted through factor analysis. The accumulative contribution ratio is 76.92％. Factor 1 indicates the degree of obesity around the chest, factor 2 is the drooping degree of breast, factor 3 is the contours and prominence, factor 4 is the breast breadth and breadth of bust point, factors 5 is the volume of breast. The subject were classified into 3 cluster as their breast types through cluster analysis. Type 1 is the closest to the ideal breast shape and not too droopy. This group belonged to 75A. Type 2 has small breast and belonged to 70AA group. Type 3 is the obesest and has the biggest and droopy breast. This group belonged to 75B. The distribution of size of brassiere had 3 sections from 70 to 80 showing a rate of 81.94% and the sin of the cup had 4 sections from AAA cup to B cup showing a rate of 89.70％. The production ratio of each brassiere size, it was found that the brassiere size of highest production ratio was 75A(16.39％) in type 1,70AA(16.27%) in type 2, and 75B(13.72％) in type 3. This suggests that it is necessary to adjust for the production rate of brassieres.

• 한국항만경제학회지
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• 제35권3호
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• pp.41-60
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• 2019

본 연구는 의약품 물류업체를 대상으로 물류센터 선정시 고려하는 요인들을 파악하고 그 요인들에 대한 중요도-만족도를 분석함으로 현재의 의약품 물류센터입지의 개선방안을 제공하였다. 첫째, 물류센터선정시 고려요인은 물류요인, 경제요인, 환경요인, 정책요인으로 구분되고 각 요인에 포함된 구체적인 속성들에 대해서는 대부분이 중요도에 비해 만족도가 낮은 것으로 나타났다. 둘째, 의약품 물류센터 이용자들은 생산업체, 유통업체, 병-의원, 약국으로 구분하고 각 이용자별 분석결과, 물류 요인은 개선이 필요하고 환경요인은 과잉투자된 것으로 확인되었다. 이러한 연구 결과는 향후 의약품 유통업체들이 물류센터를 선정하는데 있어 방향성을 제시해 줄 수 있으며, 전략적 시사점을 제공할 수 있을 것으로 기대한다.

• 한국군사과학기술학회지
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• 제19권3호
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• pp.281-287
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• 2016

The purpose of this study is to analyze the vibration characteristics and develop a mounting which can improve the strength safety factor to replace the high failure rate APU(auxiliary power unit) imported metal mounts with rubber mount that can be domestically produced. For this study, we analyzed in 3 kinds of rubber mounts hardness for the natural frequency to avoid the average excited frequency of the APU. In addition, allowed vibration acceleration of rubber mount confirmed to 90.8 g by adding a strength safety factor. To assure the validity of the design, we measure the vibration acceleration equipped with a metal mount and rubber mount 2 species(Hs 50 and 60). As a result, the proposed design method in this study is reasonable because the rubber mounts is excellent strength safety factor and vibration transmissibility than metal mounts.

• 대한안전경영과학회지
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• 제19권4호
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• pp.141-148
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• 2017

This researcher selected basic variable to investigate the effective relations of establishment and management of resting facility on reduction of constructional disasters and safety accidents and improvement of working efficiency for construction workers. Based on the measured variables, this researcher investigated phenomenon, recognition and satisfaction for using and demanding resting facility by long-term construction in construction site for workers of huge construction site in Seoul, conducted survey of total 219 questionnaires so as to grasp implications of workers' resting facility demanded in long-term huge construction site and effects on reduction of disasters and conducted structural equation analysis. As a result, resting faciity factor, management factor, and hygienic service factor were significant and resting and food factors were not significant. Therefore, it's expected to reduce personal disaster by improving quality of constructional resting facility, hygienic service, and resting facility management and especially, resting facility management factor makes lots of effects on prevention of personal disasters, so it was a strongly main factor. By suggesting the guideline of establishment and management service of proper resting facility through this research, positive recognition and constructional disaster reduction can be expected in construction site.