• 한국철도학회논문집
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• 제12권6호
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• pp.936-943
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• 2009

본 연구에서는 철도사고 위험분석 및 위험도 평가절차에 따라 철도건널목사고에 대한 정량적인 위험도평가를 위한 모델을 사건수목 및 고장수목 분석기법을 이용하여 개발하였다. 위험사건이 발생하여 인명피해로 결과하는 과정에서의 영향인자들을 분석하여 사고진전 시나리오를 구성하였으며, 고장수목분석(FTA, Fault Tree Analysis)을 이용하여 시나리오 경로별 발생확률을 산정하고, 사건수목분석(ETA, Event Tree Analysis)을 이용하여 심각도 값을 산정함으로써 이들의 조합으로 위험도를 산정하는 위험도 평가 모델을 제시하였다. 또한 실제발생한 위험도값과 개발모델을 이용하여 산정된 위험도값의 비교를 통하여 개발모델의 신뢰성 및 타당성을 검증하였다.

• 신재생에너지
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• 제9권2호
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• pp.40-50
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• 2013

Government spending on research and development increased continuously is much more important to decision-making methodology for rational investment. Rely on a group of minority experts in the application of a general methodology, a tipping effect occur in specific technology field or difficult balanced procedure and objective control to maintain. This paper presents a qualitative-quantitative methodology to avoid such risks by utilizing Technology-Tree pertaining to energy R&D planning of the government Energy Technology Development program. Especially Energy Technology Development program "energy storage system" is applied to the analysis of Technology-Tree, mapping and analysis of existing government-supported projects during the recent 5 years, is derived essential missing elements of the technology value chain. This study suggests that significant evidence is utilized for improving efficiency of government R&D budget considering the importance of technology, domestic research-based and so forth, could be used to implement the R&D project planning.

• 전자공학회논문지CI
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• 제45권5호
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• pp.56-62
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• 2008

의사결정나무를 구성하여 강판튜브 비파괴평가에 사용하는 산업용 CR영상의 측정 패턴인식을 도모한다. 본래 비파괴평가는 기계학습기법에 의한 패턴식별과 그 분류에 적합한 분야이다. 의사결정나무의 속성들은 비파괴평가 테스트 절차로부터 취한다. 방사선조사 입사각, 경사도 및 거리 둥의 기하학적 특성들은 입력 영상 데이터 분석으로부터 추정한다. 이 요소들은 대상 입력을 의사결정나무에서 미리 정해진 분류에로 정확히 그리고 쉽게 분류가 이루어지도록 한다. 이 알고리즘은 비파괴평가 결과의 특성화를 간단히 하며 특성 결정을 간편하게 한다. 실험 결과는 제안한 알고리즘의 유용성을 보였다.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2238-2249
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• 2020

In a seismic PSA, dependency among seismic failures of components has not been explicitly modeled in the fault tree or event tree. This dependency is separately identified and assigned with numbers that range from zero to unity that reflect the level of the mutual correlation among seismic failures. Because of complexity and difficulty in calculating combination probabilities of correlated seismic failures in complex seismic event tree and fault tree, there has been a great need of development to explicitly model seismic correlation in terms of seismic common cause failures (CCFs). If seismic correlations are converted into seismic CCFs, it is possible to calculate an accurate value of a top event probability or frequency of a complex seismic fault tree by using the same procedure as for internal, fire, and flooding PSA. This study first proposes a methodology to explicitly model seismic dependency by converting correlated seismic failures into seismic CCFs. As a result, this methodology will allow systems analysts to quantify seismic risk as what they have done with the CCF method in internal, fire, and flooding PSA.

• 한국경영과학회지
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• 제25권3호
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• pp.17-33
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• 2000

We consider the Steiner tree packing problem. For a given undirected graph G =(V, E) with positive integer capacities and non-negative weights on its edges, and a list of node sets(nets), the problem is to find a connection of nets which satisfies the edge capacity limits and minimizes the total weights. We focus on the switchbox routing problem in knock-knee model and formulate this problem as an integer programming using Steiner tree variables. The model contains exponential number of variables, but the problem can be solved using a polynomial time column generation procedure. We test the algorithm on some standard test instances and compare the performances with the results using cutting plane approach. Computational results show that our algorithm is competitive to the cutting plane algorithm presented by Grotschel et al. and can be used to solve practically sized problems.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2003년도 Proceeding
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• pp.50-56
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• 2003

In the development of complex software system, it is important to use hierarchical use case model due to the complex scope of development procedure. The use case model is core factor of the OMG (Object Management Group)'s UML (Unified Modeling Language) diagrams. In this paper, we propose a novel method to check syntactic consistency automatically in use case models at the different level of abstraction. This method is a rule-based approach which utilizes actor tree, use case tree and use case description. The proposed method is simulated on ITS (Intelligent Transportation System) architecture for the verification.

• Communications for Statistical Applications and Methods
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• 제3권3호
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• pp.125-133
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• 1996

In this paper, we present a algebraic technique for computing system reliability for complex system. The method was originally developed as an aid to fault tree analysis but it applies to general problems of reliability assessment. A success expression which directly gives the reliability expression is formed and simplified by the procedure. Several algorithms and examples are illustrated.

• 산업경영시스템학회지
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• 제42권4호
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• pp.183-193
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• 2019

Process mining is an analytical technique aimed at obtaining useful information about a process by extracting a process model from events log. However, most existing process models are deterministic because they do not include stochastic elements such as the occurrence probabilities or execution times of activities. Therefore, available information is limited, resulting in the limitations on analyzing and understanding the process. Furthermore, it is also important to develop an efficient methodology to discover the process model. Although genetic process mining algorithm is one of the methods that can handle data with noises, it has a limitation of large computation time when it is applied to data with large capacity. To resolve these issues, in this paper, we define a stochastic process tree and propose a tabu search-genetic process mining (TS-GPM) algorithm for a stochastic process tree. Specifically, we define a two-dimensional array as a chromosome to represent a stochastic process tree, fitness function, a procedure for generating stochastic process tree and a model trace as a string of activities generated from the process tree. Furthermore, by storing and comparing model traces with low fitness values in the tabu list, we can prevent duplicated searches for process trees with low fitness value being performed. In order to verify the performance of the proposed algorithm, we performed a numerical experiment by using two kinds of event log data used in the previous research. The results showed that the suggested TS-GPM algorithm outperformed the GPM algorithm in terms of fitness and computation time.

• 대한안전경영과학회지
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• 제6권2호
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• pp.211-229
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• 2004

The basis of cyber trading has been sufficiently developed with innovative advancement of Internet Technology and the tendency of stock market investment has changed from long-term investment, which estimates the value of enterprises, to short-term investment, which focuses on getting short-term stock trading margin. Hence, this research shows a Short-term Stock Price Forecasting System on Learning Agent System using DTA(Decision Tree Algorithm) ; it collects real-time information of interest and favorite issues using Agent Technology through the Internet, and forms a decision tree, and creates a Rule-Base Database. Through this procedure the Short-term Stock Price Forecasting System provides customers with the prediction of the fluctuation of stock prices for each issue in near future and a point of sales and purchases. A Human being has the limitation of analytic ability and so through taking a look into and analyzing the fluctuation of stock prices, the Agent enables man to trace out the external factors of fluctuation of stock market on real-time. Therefore, we can check out the ups and downs of several issues at the same time and figure out the relationship and interrelation among many issues using the Agent. The SPFA (Stock Price Forecasting System) has such basic four phases as Data Collection, Data Processing, Learning, and Forecasting and Feedback.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.435-440
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• 2018

본 연구의 목적은 기존의 심전도 측정 방법과 새로 발명된 일체형 심전도의 효과에 대한 비교분석을 시행하여 실행효과를 확인하기 위함이다. 이를 위해 46세의 건강한 남성모델을 대상으로 연구에 대한 정보가 없는 심전도 측정 유경험자를 대상으로 진행하였다. 기간은 2018년 6월 1일에서 6월 15일까지 한 기관에 연구와 회의로 내방한 인원 중에서 참여자를 선발하였고 이들에게 12리드형 기존 심전도(C)와 새로 개발된 심전도 방법인 SIM-Tree(SIM)를 간단한 교육 후 시행하여 참가자의 특성, 시행만족도, 각 단계별 시간, 그리고 연구에 대한 정보가 없는 순환기내과 교수의 일치도를 측정 비교하였다. 연구결과, 전체 참여자는 104명이었으며, 전체 시행시간은 SIM이 평균 65.39초로 C의 평균 94.38초에 비해서 통계적으로 빨랐다(p<0.05). 참가자의 만족도 조사에서 SIM이 평균 97.69로 C의 평균 68.5초에 비해서 높게 나타났다(p<0.05). 순환기 내과 교수를 통한 일치도 분석에서 급내상관계수(Intra-class correlation coefficient, ICC)점수가 0.959점으로 충분히 높게 나타났다(p<0.05). 결론적으로 새로 개발 된 SIM-Tree는 시술시간과 만족도에서 기존방법에 비해 효과적으로 나타났고 측정결과에서 기존방법과 높은 일치도를 보였다.