• 대한토목학회논문집
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• 제12권4호
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• pp.129-134
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• 1992

본 논문은 도시유역의 최적 배수관망설계를 위한 위험도-안전도계수 관계를 설정하는 것이다. 배수관망의 신뢰도 분석을 위하여는 하수관의 용량과 하중을 결정하는 식을 구성하는 여러가지 매개변수들의 불확실성이 고려되어야 하며, 이에 따른 위험도를 결정하게 된다. 본 연구에서는 신뢰도 분석기법을 유역면적 $381,000m^2$인 성산 유수지 유역에 적용하였다. 하수관망의 용량을 결정하는 식으로는 Darcy-Weisbach식을, 하중을 결정하는 식으로는 합리식을 사용하였으며, 하수관의 용량과 설계유량과의 비로 나타나는 안전도계수를 구하여 이를 하수관망의 위험도와 상관시켰다. 이에 따라 재현기간별 위험도-안전도계수를 얻었으며, 이는 배수관망의 최적설계에 이용될 수 있다.

• 한국진공학회지
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• 제16권6호
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• pp.458-462
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• 2007

타원편광분석법은 반도체 물질의 광 특성과 전이점 연구에 유용하게 쓰이는 기술이다. 측정된 유전율 함수로부터 전이점을 구하기 위해서 전통적으로 이차 미분스펙트럼을 이용하여 분석하는데, 이 방법은 high frequency 의 잡음을 크게 증폭시키는 단점이 있다. 본 연구에서는 역 공간 푸리에 변환 (Fourier transform)을 이용하여 low-, medium-, high-index 의 푸리에 계수로부터 baseline, 정보, high frequency 잡음을 분리하는 방법을 소개하고자 한다. 이 방법을 이용하여 광전자소자에 폭넓게 사용되는 ZnCdSe 화합물 반도체의 $E_1,\;E_1+{\Delta}_1$ 전이점에 대한 연구를 하여 전통적인 이차 미분법과 비교해 보았다.

• Computers and Concrete
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• 제9권2호
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• pp.81-97
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• 2012

This paper presents development of double-K fracture model for the split-tension cube specimen for determining the unstable fracture toughness and initial cracking toughness of concrete. There are some advantages of using of split-tension cube test like compactness and lightness over the existing specimen geometries in practice such as three-point bend test, wedge splitting test and compact tension specimen. The cohesive toughness of the material is determined using weight function having four terms for the split-tension cube specimen. Some empirical relations are also suggested for determining geometrical factors in order to calculate stress intensity factor and crack mouth opening displacement for the same specimen. The results of double-K fracture parameters of split-tension cube specimen are compared with those obtained for compact tension specimen. Finally, the influence of the width of the load-distribution of split-tension cube specimen on the double-K fracture parameters for laboratory size specimens is investigated. The input data required for determining double-K fracture parameters for both the specimen geometries are obtained using well known version of the Fictitious Crack Model.

• International Journal of Aeronautical and Space Sciences
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• 제4권2호
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• pp.1-8
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• 2003

Satellite formation flying is the placing micro-satellites with the same mission into nearby orbits to form a cluster. Clohessy-Wiltshire equations are used to describe the relative motion and control strategies between satellites within a cluster, which are known as Hill's equations. Even though Hill's equations are powerful in determining initial conditions for the satellite formation flying, they can not accurately express the relative motion under J2 perturbation. Some methods have been developed for the determination of initial conditions to avoid limits of Hill's equation. This paper gives a new method of determining initial conditions using mean elements. For this research mean elements were transformed to osculating elements using Brouwer's theory and the orbit was propaeated with the consideration of J2-J8 to get a relative position. The results show that satellites within a cluster are maintained in the desired boundary for long period and the method is effective on a fuel saving for satellite formation flying.

• Journal of Information Technology Applications and Management
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• 제11권1호
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• pp.137-159
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• 2004

In the past days, most of studies about website and Online behavior have been mainly focused on the adoption of website and internet shopping or internet shopping mall. But the model of website revisit behavior has not been made and the leading theory of website usage behavior has not been existed. Lately, many researches on commercial website revisiting behavior are emphasizing the role of intention, attitude, satisfaction in online visiting behavior such as Jarvenpaa et al. [1997, 1999, 2000], Wang et al. [2001], Moon & Kim [2001], Heijden[2003], Sultan et al. [2002], Yoon [2000], Shankar et al. [2002a, 2002b], Mcknight et al. [2002], Chen & Dhillon [2003] and so on. The purpose of this paper is two-folds. The one is to find the affecting factors on the website users' revisit behavior in commercial website and the other is to search more influencing ones on the determinant factors, to analyze research model using in LISREL. The EFA and reliability test was executed by for finding the validity and reliability, covariance matrix analysis was executed for the purpose of testing the 13 hypotheses. The major finding of this paper would be summarized as followed : (1) The roles of satisfaction and attitude to the revisit behavior are very important and both variables have determining effects in commercial website revisit behavior. (2) The determining factors in positively affecting website users' satisfaction are attitude, perceived usefulness, design. (3) The determining factors in positively affecting website users' attitude are perceived usefulness, design, perceived ease of use, and negatively affecting factor was perceived risk in website.

• 대한임베디드공학회논문지
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• 제12권3호
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• pp.159-167
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• 2017

Software safety is a key issue in embedded system of automotive and aviation industries. Various software testing approaches have been proposed to achieve software safety like ISO26262 Part 6 in automotive environment. In spite of one of the classic and basic approaches, stack memory is hard to estimating exactly because of uncertainty of target code generated by compiler and complex nested interrupt. In this paper, we propose an approach of analyzing the maximum stack usage statically from target binary code rather than the source code that also allows nested interrupts for determining the exact stack memory size. In our approach, determining maximum stack usage is divided into three steps: data extraction from ELF file, construction of call graph, and consideration of nested interrupt configurations for determining required stack size from the ISR (Interrupt Service Routine). Experimental results of the estimation of the maximum stack usage shows proposed approach is helpful for optimizing stack memory size and checking the stability of the program in the embedded system that especially supports nested interrupts.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2004년도 The 3rd Annual Conference for The Korean Society for Bioinformatics Association of Asian Societies for Bioinformatics 2004 Symposium
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• pp.124-130
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• 2004

Microarray expression datasets are incessantly cumulated with the aid of recent technological advances. One of the first steps for analyzing these data under various experimental conditions is determining differentially expressed genes (DEGs) in each condition. Reasonable choices of thresholds for determining differentially expressed genes are used for the next -step-analysis with suitable statistical significances. We present a model for identifying DEGs using pathway information based on the global connectivity structure. Pathway information can be regarded as a collection of biological knowledge, thus we are tying to determine the optimal threshold so that the consequential connectivity structure can be the most compatible with the existing pathway information. The significant feature of our model is that it uses established knowledge as a reference to determine the direction of analyzing microarray dataset. In the most of previous work, only intrinsic information in the miroarray is used for the identifying DEGs. We hope that our proposed method could contribute to construct biologically meaningful network structure from microarray datasets.

• 대한예방한의학회지
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• 제15권3호
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• pp.115-125
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• 2011

Objectives : The aim of this study is to investigate the relevant factors which determine the use of oriental healthcare services among subjects with chronic illnesses. Method : This study utilized the data from the Korean National Health and Nutrition Examination Survey in 2005. Out of all the participants of the survey, 11,665 individuals who are older than 19 years old and have one or more chronic diseases were included in this study. Results : The factors that affect utilization of oriental healthcare services were significantly associated with gender, educational level, job, personal income, the number of chronic illnesses, experiences of nontreatment or delayed treatment and admission experiences for the last one year(p<.001). Although some of these factors need further studies, the determining factors for the use of oriental healthcare services are the presence of chronic illness and the number of chronic disease. That is, the chronically ill are more likely to seek oriental healthcare services. And the more chronic diseases the clients have the higher probability of seeking oriental healthcare services was found. Conclusions : The results suggest that the national integrated care services should be established for diverse development of policy regarding the quality of care of chronic illness and cost-effectiveness.

• Structural Engineering and Mechanics
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• 제65권1호
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• pp.111-120
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• 2018

This paper presents a new and simple solution for determining the natural frequencies of framed tube combined with shear-walls and tube-in-tube systems. The novelty of the presented approach is based on the bending moment function approximation instead of the mode shape function approximation. This novelty makes the presented solution very simpler and very shorter in the mathematical calculations process. The shear stiffness, flexural stiffness and mass per unit length of the structure are variable along the height. The effect of the structure weight on its natural frequencies is considered using a variable axial force. The effects of shear lag phenomena has been investigated on the natural frequencies of the structure. The whole structure is modeled by an equivalent non-prismatic shear-flexural cantilever beam under variable axial forces. The governing differential equation of motion is converted into a system of linear algebraic equations and the natural frequencies are calculated by determining a non-trivial solution for the system of equations. The accuracy of the proposed method is verified through several numerical examples and the results are compared with the literature.

• 한국철도학회논문집
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• 제14권3호
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• pp.216-221
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• 2011

수리 가능한 시스템의 신뢰성 분석에 중요한 문제 중의 하나는 유지보수 효과를 모델링하는 것이다. 현재까지 많은 연구들은 유지보수 후 시스템의 상태가 새것과 같이 된다는 완전유지보수 또는 유지보수 바로 직전의 상태로 된다는 최소유지보수 모형을 사용하였다. 그러나 국내운영기관에서 시행하는 유지보수 형태는 완전유지보수와 최소유지보수의 사이의 효과를 가지는 불완전유지보수 형태로 시행하는 경우가 많다. 본 연구에서는 이와 같이 불완전 유지보수가 수행되는 전동차의 장치들 중에서 승객용 도어시스템(PDS:passenger door system)의 고장데이터를 분석하고 유지보수 효과 수준을 적용하여 불완전유지보수 주기를 결정하는 문제를 다루었다.