• Nuclear Engineering and Technology
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• 제51권3호
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• pp.702-708
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• 2019

This paper deals with break size estimation of loss of coolant accidents (LOCA) using a nonlinear autoregressive with exogenous inputs (NARX) neural network. Previous studies used static approaches, requiring time-integrated parameters and independent firing algorithms. NARX neural network is able to directly deal with time-dependent signals for dynamic estimation of break sizes in real-time. The case studied is a LOCA in the primary system of Bushehr nuclear power plant (NPP). In this study, number of hidden layers, neurons, feedbacks, inputs, and training duration of transients are selected by performing parametric studies to determine the network architecture with minimum error. The developed NARX neural network is trained by error back propagation algorithm with different break sizes, covering 5% -100% of main coolant pipeline area. This database of LOCA scenarios is developed using RELAP5 thermal-hydraulic code. The results are satisfactory and indicate feasibility of implementing NARX neural network for break size estimation in NPPs. It is able to find a general solution for break size estimation problem in real-time, using a limited number of training data sets. This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr NPP.

• 대한환경공학회지
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• 제29권8호
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• pp.857-863
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• 2007

• Journal of applied mathematics & informatics
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• 제20권1_2호
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• pp.119-132
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• 2006

This paper presents an approach for using right-truncated exponentially distributed random variables to model activity times in stochastic activity networks. The advantages of using the right-truncated exponential distribution are discussed. The moments of a project completion time using the proposed distribution are derived and compared with other estimated moments in literature.

• 경영과학
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• 제12권3호
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• pp.77-95
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• 1995

This paper shows the case study of risk analysis in an weapon system research and development project. For risk analysis, an advanced stochastic networking technique-VERT (Venture Evaluation and Review Technique) is used. Assumptions for activities of network diagram and conversion methods from PERT ( Program Evaluation and Review Technique) to VERT are discussed. Also, simulation result is presented and discussed.

• 디지털융복합연구
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• 제12권8호
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• pp.309-319
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• 2014

국제적으로 논의되고 있는 미래 인터넷의 핵심 특징 중의 하나는 네트워크 가상화 서비스 이다. 최근 논의되고 있는 네트워크 가상화 기술에는 네트워크 기능요소의 가상화와 가상 네트워크 서비스의 두 가지 접근 방법이 있다. 미국의 GENI를 비롯한 여러 국가의 연구망을 중심으로 미래 인터넷 기술을 실험하고 있으며 그 중 가상화 서비스가 주요 이슈에 포함되어 있다. 국내 대표적인 연구망인 KREOENT에서도 미래 인터넷 서비스 도입을 위한 단계로서 미래 인터넷을 위한 핵심 네트워크 모델인 SDN/OpenFlow의 가상화 모델을 사용하여 가상 네트워크 프레임워크 구축을 추진하고 있다. 이를 위해 본 논문에서는 KREONET에서 가상 네트워크 서비스를 도입하기 위한 단계적 모델을 제시한다. 먼저 KREONET 사용자의 가상 네트워크 서비스 요구사항을 분석하고, 요구사항을 만족시킬 수 있는 자원 관리 방안 및 가상 네트워크 구축 방안을 제시한다. 마지막으로 KREONET 가상 네트워크 모델의 타당성을 검증한다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.642-652
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• 2007

Many contracting firms and project managers in the construction industry have started to utilize multi objective optimization methods to handle multiple conflicting goals for completing the project within the stipulated time and budget with required quality and safety. These optimization methods have increased the pressure on decision makers to search for an optimal resources utilization plan that optimizes simultaneously the total project cost, completion time, and crashing cost by considering indirect cost, contractual penalty cost etc., practically charging them in terms of direct cost of the project which is fuzzy in nature. This paper presents a multiple fuzzy goal programming model (MFGP) that supports decision makers in performing the challenging task. The model incorporates the fuzziness which stems from the imprecise aspiration levels attained by the decision maker to these objectives that are quantified through fuzzy linear membership function. The membership values of these objectives are then maximized which forms the fuzzy decision. The problem is solved using LINGO 8 optimization solver and the best compromise solution is identified. Comparison between solutions of MFGP, fuzzy multi objective linear programming (FMOLP) and multiple goal programming (MGP) are also presented. Additionally, an interactive decision making process is developed to enable the decision maker to interact with the system in modifying the fuzzy data and model parameters until a satisfactory solution is obtained. A case study is considered to demonstrate the feasibility of the proposed model for optimization of project network parameters in the construction industry.

• 환경영향평가
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• 제17권1호
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• pp.57-66
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• 2008

Follow-up process consists of two steps. First, it monitors whether project proponents comply with reviews made by KEI. The second steps is to survey environmental impacts during and after implementation of the proposed action. The follow-up requires the proper participation of stakeholders: project proponents, compliance monitors, impact monitors, and environmental agencies approving and reviewing said projects. Currently, follow-up process does not work well because each stakeholder does not play his proper role for various reasons such as mutual distrust among stakeholders and problems associated with institutional settings. This study intends to improve effectiveness of follow-up process and, ultimately, to improve quality of EIA in Korea by devising a follow-up system that delineates clear roles and build a strong network among stakeholders. In order to do so, the study identifies current problems associated with follow-up process and examines basic concepts and procedures involved in it. Secondly, it analyzes relational dynamics among stakeholders to identify what's behind the current mutual distrust. Third, it proposes a way to delineate clear roles to each stakeholder so that follow-up process runs efficient as an organic network.

• 유기물자원화
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• 제23권1호
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• pp.63-69
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• 2015

본 연구는 포항철강산업단지를 대상으로 부산물 발생 현황과 현재까지 구축된 산업공생 네트워크를 분석하는데 목적을 두었다. 포항은 경상북도 시군 중 사업장 폐기물 발생량과 재활용 제외 폐기물 발생량이 모두 가장 높았으며, 대부분이 포항철강산업단지에서 발행하였다. 부산물 발생량을 조사한 결과 재활용을 제외한 폐기물 발생량의 대부분은 광재류가 차지하고 있으며 폐목재류, 분진류, 폐합성수지, 폐합성고무의 순으로 나타났다. 포항철강산업단지 입주기업간 구축된 부산물 거래 공생맵을 작성한 결과 부산물 중 폐내 화물 및 슬래그를 이용한 부산물 거래가 가장 활발하게 이루어지는 것으로 나타났다.

• 한국문헌정보학회지
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• 제34권2호
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• pp.211-232
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• 2000

국가간 자료교환(Exchange)이나 기증에 의존하는 외국정부 간행물의 수집과 검색은 전자정부시대를 맞이하면서 새로운 관리제도가 필요하게 되었다. 그에 대한 대안으로 인터넷상의 외국정부정보에 대한 메타사이트를 만들고, 서브젝트 게이트웨이를 검색모형으로 제시함으로써 외국정보에 관한 정보원개발(Collection Development)과 이용자 서비스로 이용하고자 한다. 우수한 메타사이트를 선정하기 위하여 AltaVista의 anchor 기능과 link 기능을 이용하여 계량적인 평가를 하였으며, 서브젝트 게이트웨이 검색모형으로는 분산 메타데이터베이스의 통합 검색 시스템인 Isaac Network 구조를 제시하였다.

• 한국공간정보시스템학회 논문지
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• 제11권2호
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• pp.63-72
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• 2009

Korean Land Spatialization Program (KLSP) is an R&D program of the National GIS Project for developing ubiquitous GIS technologies under the control of the M inistry of Land, Transport and Maritime Affairs (M LTM). The first program of the KLSP, which lasts from 2006 to 2012, initiated with $132 million of national funds and $42 million of private matching funds. Aiming to develop the 'Innovation of GIS technology for ubiquitous Korean land', the KLSP consists of five core research projects and one research coordination project to practically utilize and commercialize the results of core research projects. The Korean Land Spatialization Group (KLSG) is planning the KLSP Test-Bed for testing, integrating, and exhibiting the KLSP's outcomes. About 40% of the outcomes are related products to geo-sensor and wireless sensor network (W SN). Thus, interoperable, scalable and web accessible frameworks like an OGC SWE (Open Geospatial Consortium Sensor Web Enablement) are mandatory because some of the products must be connected to each other in a KLSG Test-Bed. The main objective of this paper is to introduce the KLSP Test-Bed and the SWE SOS (Sensor Observation Service) prototype, which is developed for interoperable geo-sensor networks of the KLSP.