• 한국항공우주학회지
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• 제39권2호
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• pp.106-113
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• 2011

본 논문에서는 균일 열부가 하중을 받는 사각판의 자유 진동특성을 실험을 통하여 연구하였다. 사각판의 재질은 알루미늄, 강재 및 스테인레스 강이고 사각판의 재원은 0.1 $\times$ 0.1 $\times$ 0.002 m 이다. 열부가 하중을 위해 적외선 석영 램프를 사용하였고, 전력조절을 위해 PCS(Power Control System)을 사용하였으며, 주파수 함수를 얻기 위해 비접촉식 진동측정 장비를 사용하였다. 부가한 온도 조건은 상온에서부터 $300^{\circ}C$까지 $50^{\circ}C$간격으로 부가하였다. 경계조건은 번지코드를 사용하여 자유-자유 조건을 구현하였다. 사각판의 전면 전체를 균일하게 가열하였다.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1686-1693
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• 2014

In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

• 정보처리학회논문지B
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• 제15B권1호
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• pp.1-8
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• 2008

일반적으로 감시영상에서 움직이는 물체들은 배경빼기 혹은 프레임 차를 이용하여 추출된다. 하지만 객체에 의해서 만들어지는 그림자는 심각한 탐지의 오류를 야기시킬 수 있다. 특히, 도로 상에 설치된 감시카메라로부터 획득된 영상으로부터 차량 정보를 분석할 때, 차량에 의해서 생성되는 그림자로 인하여 차량의 모양을 왜곡시켜 부정확한 결과를 만든다. 때문에 그림자의 제거는 감시 영상 내에서의 정확한 객체 추출을 위해서 반드시 필요하다. 본 논문은 도로감시영상 내에서 움직이는 차량의 차종판별 성능을 향상시키기 위한 움직이는 객체 내에 만들어지는 그림자를 제거한다. 제거된 객체의 영역은 소실점을 이용하여 3차원 객체로 피팅(Fitting)한 후 측정된 데이터를 감독 학습하여 원하는 차종 판별결과를 얻는데 사용한다. 실험은 3가지 기계학습 방법{IBL, C4.5, NN(Neural Network)}을 이용하여 그림자의 제거가 차종의 판별성능에 미치는 결과의 평가한다.

• 한국가스학회지
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• 제18권5호
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• pp.6-11
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• 2014

차량용 LNG 연료 용기의 내진동 단열 지지구조 최적화 설계 개발을 위하여 종래의 해외특허구조 설계를 기본으로 한 특성요인도 분석으로 용기의 내조 및 외조 지지부 구조설계의 주요 설계 인자를 도출하였다. 도출된 설계인자 중에서 우선적으로 지지 봉재의 직경과 단열 격판 연결부 곡률을 대상으로 하여 최적화를 수행하였다. 차량용 LNG 연료 용기 설계안에 대한 평가를 위해 설계안을 MSC/MARC 상용유한 요소해석 패키지를 활용하여 유한요소 모델링하여 진동모드해석과 열전달 및 열응력해석을 수행하였다. 최적화 설계 결과를 통하여 도출된 설계안은 고유진동해석을 통한 1차 모드 고유진동수(1st Mode Natural Frequency), 열전달해석을 통한 초저온 용기 내조 외조간 지지부를 통한 총전열량 및 열응력해석을 통한 최대 Von-Mises 응력이 모두 설계 목표치를 만족하였으며, 개발된 설계안에 따라 차량용 LNG 연료 용기의 제작하여 3차원 진동 시험과 단열성능 시험을 통해 설계를 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.993-1002
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• 2016

Hepatitis is a major public health problem all around the world. This paper proposes an automatic disease diagnosis system for hepatitis based on Genetic Algorithm (GA) Wavelet Kernel (WK) Extreme Learning Machines (ELM). The classifier used in this paper is single layer neural network (SLNN) and it is trained by ELM learning method. The hepatitis disease datasets are obtained from UCI machine learning database. In Wavelet Kernel Extreme Learning Machine (WK-ELM) structure, there are three adjustable parameters of wavelet kernel. These parameters and the numbers of hidden neurons play a major role in the performance of ELM. Therefore, values of these parameters and numbers of hidden neurons should be tuned carefully based on the solved problem. In this study, the optimum values of these parameters and the numbers of hidden neurons of ELM were obtained by using Genetic Algorithm (GA). The performance of proposed GA-WK-ELM method is evaluated using statical methods such as classification accuracy, sensitivity and specivity analysis and ROC curves. The results of the proposed GA-WK-ELM method are compared with the results of the previous hepatitis disease studies using same database as well as different database. When previous studies are investigated, it is clearly seen that the high classification accuracies have been obtained in case of reducing the feature vector to low dimension. However, proposed GA-WK-ELM method gives satisfactory results without reducing the feature vector. The calculated highest classification accuracy of proposed GA-WK-ELM method is found as 96.642 %.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.489-494
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• 2004

In this paper, we investigated impurities content and thermal properties showing by changing the content of carbon black which is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens was measured by ICP-AES(Inductively Coupled Plasma Atomic Emission Spectrometer), and density of specimens were measured by density meter. And then heat capacity(${\Delta}H$) and melting temperature(Tm), specific heat(Cp) were measured by DSC(Differential Scanning Calorimetry). The dimension of measurement temperature was $0[^{\circ}C]\;to\;200[^{\circ}C]$, and rising temperature was $4[^{\circ}C/min]$. Impurities content was highly measured according to increasing the content of carbon black from this experimental result also density was increased according to these properties. Specially, impurities content values of the A1 and A2 of existing resins were measured more than 4000[ppm]. Heat capacity, melting temperature, and specific heat from the DSC results were simultaneously decreased according to increasing the content of carbon black. Because metallic impurities of carbon black having Fe, Co, Mn, A1 and Zn are rapidly passed kinetic energy increasing the number of times breaking during the unit time with the near particles according to increasing vibration of particles by the applied heat energy.

• 동의신경정신과학회지
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• 제28권2호
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• pp.61-72
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• 2017

Objectives: The Yin-Yang temperament and the Sasang Personality Questionnaire (SPQ) were reported to have relations with psychopathological problems in adolescents. The purpose of this study was to examine how domains of Yin-Yang temperament influence on problem behaviors in Korean middle school students. Methods: Subjects of 681 Korean middle school students completed the SPQ for measuring Yin-Yang temperament and the Youth Self-Report (YSR) for measuring problem behaviors. The differences of problem behaviors between Yin and Yang temperament groups were tested with T-test and profile analysis. The associations of the SPQ subscales on problem behaviors was also examined with Pearson's correlation and regression analysis. Results: Yang temperament was related to the externalizing problem while Yin temperament to the internalizing problem. The Emotionality and Behavior dimension of Yin-Yang temperament were found to be a factor of susceptibility and resilience for problem behaviors, respectively. Three dimensions of Yin-Yang temperament have different influences on externalizing and internalizing problems depending on the sex and Yin-Yang temperament groups of subjects. Conclusions: The Yin-Yang temperament would be useful for predicting and preventing the problem behaviors of middle school students. This study would be useful for screening the psychopathological problems and helping Korean adolescents to develop healthy character.

• Molecules and Cells
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• 제40권2호
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• pp.117-122
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• 2017

Despite the fact that porcine embryonic stem cells (ESCs) are a practical study tool, in vitro long-term maintenance of these cells is difficult in a two-dimensional (2D) microenvironment using cellular niche or extracellular matrix proteins. However, a three-dimensional (3D) microenvironment, similar to that enclosing the inner cell mass of the blastocyst, may improve in vitro maintenance of self-renewal. Accordingly, as a first step toward constructing a 3D microenvironment optimized to maintain porcine ESC self-renewal, we investigated different culture dimensions for porcine ICM-derived cells to enhance the maintenance of self-renewal. Porcine ICM-derived cells were cultured in agarose-based 3D hydrogel with self-renewal-friendly mechanics and in 2D culture plates with or without feeder cells. Subsequently, the effects of the 3D microenvironment on maintenance of self-renewal were identified by analyzing colony formation and morphology, alkaline phosphatase (AP) activity, and transcriptional and translational regulation of self-renewal-related genes. The 3D microenvironment using a 1.5% (w/v) agarose-based 3D hydrogel resulted in significantly more colonies with stereoscopic morphology, significantly improved AP activity, and increased protein expression of self-renewal-related genes compared to those in the 2D microenvironment. These results demonstrate that self-renewal of porcine ICM-derived cells can be maintained more effectively in a 3D microenvironment than in a 2D microenvironment. These results will help develop novel culture systems for ICM-derived cells derived from diverse species, which will contribute to stimulating basic and applicable studies related to ESCs.

• 한국식생활문화학회지
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• 제10권4호
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• pp.327-337
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• 1995

The purposes of this study were to: (a) identify college students' patronage behaviors, (b) develop an instrument measuring the attitudes of University Students towards university foodservices management practices, (c) determine university students' attitude towards the four types of university foodservices, and (d) provide recommendations on marketing strategies for university foodservice. Questionnaires were hand delivered to 600 Yonsei University students by designated coordinators. A total of 549 questionnaires were usable; resulting in an 93.3% response rate. The survey was conducted between November 28 to December 4, 1995. Statistical data analysis was completed using the SAS Programs for descriptive analysis, T-test, ${\chi}^2$ test, ANOVA, Factor Analysis and Stepwise Multiple Regression. Most (88.3%) of students were patronizing university foodservices for lunch. Underground student foodservice (40.1%) and Restaurants outside the campus (33.7%) were primarily used for lunch and dinner respectively. Eighty six percent of university students had 1 to 2 meals per day at university foodservices. The reasons given by students for patronizing university foodservices were as follows: location, time, price, menu, taste. Most of the respondents were least satisfied with hygiene, taste, menu and atmosphere. Data indicated strong support for eight priori dimensions in terms of food, menu, atmosphere, hygiene, employee attitude, facilities and convenience. After the factor analysis, price, fast service and foodservice location attributes were rearranged, combined and created a new dimension called as 'access'. Three dimensions in terms of menu, hygiene, convenience were important to students although performance was perceived as poor through importance-performance analysis. Most of students were not satisfied with all four types of university foodservices. In terms of food quality and price which university foodservices offer, most of respondents were moderately satisfied. According to multiple regression analysis, 93.31% of the variance respondents' satisfaction score could be explained by food, menu, price, atmosphere, hygiene, employee attitude, facilities, and convenience dimensions.

• 미술이론과 현장
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• 제3호
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• pp.173-192
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• 2005

Yoo Youngkuk started his career as an artist when he entered Bunkagakuin of Tokyo in 1935 he actively participated in the Japanese art scene as a young Korean artist until 1943. In his earliest works, Rhapsody and Work B, Surrealist and abstract influences are manifested as these were prevalent in Japan at the time. With the exception of Rhapsody and Work B, all works available that were executed between 1937 and 1940 are abstract, which points to the fact that Yoo intended abstraction from the beginning. Surviving works in relief suggest his early style was founded on the abstractions similar to Russian Avant-Garde, Neo-plasticism and Bauhaus simplicity. His early abstractions were not the ideational images derived in the process of the abstraction of the representational image, but they arose from the constructive attitude in composing the already stylized non-representational geometries. It is worth noting that his early emphasis was on the pure and absolute geometric abstraction, rather than the images motivated from the figurative representation. Yoo differentiates himself from Kim Whan Ki in the following aspects: one, he eliminated the subject matter i.e. human figures and the nature; two, he maintained the constructivist attitude in creating a strict and absolute abstraction; three, he experimented with different styles without combining them. He manifests direct influences from the prevalent Western art influences, such as Futurism and Russian Avant-Garde, unlike Kim who vaguely references. In both paintings and reliefs, Yoo's attempt in the realization of the pictorial depth and space seems cerebral and conceptualized compared with the other artists of the time who resolved abstraction via the constructive dimension. Uemura, a contemporary critic to the geometric abstractions in Japan, disapproves the stylistic bent in the adaptation of the abstract painting without the comprehension of its spiritual movement. As witnessed in other criticisms as well, contemporary Japanese critics' interest lie mainly in the superficial observation such as the presence of representational elements, composition and use of color. Such formal and superficial understanding of the geometric abstraction resulted in