• 한국가스학회지
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• 제16권6호
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• pp.41-47
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• 2012

화학공정을 효율적으로 설계 및 관리하기 위한 도면으로 공정흐름도와 공정배관 계장도가 있다. 본 도면들은 공정의 운전조건 및 설비에 대한 정보를 제공하지만 공정이 정상적으로 운전할 신뢰도는 제공하지 못한다. 따라서 본 연구에서는 유향그래프 분석기법을 이용하여 화학공정의 예방점검 정비주기 및 시점을 결정하기 위한 정보를 제공할 수 있는 신뢰도흐름도를 개발하였다. 유향그래프 분석기법은 화학공정이 정상적으로 작동할 가능성을 평가할 수 있는 기법으로써 노드와 아크를 사용하여 화학공정을 유향그래프로 모델화하고, 이 유향그래프를 순차적으로 해석하여 화학공정의 신뢰도를 평가하는 기법이다. 본 연구에서는 운전시간에 따른 화학공정의 신뢰도를 분석하고, 그 결과를 공정배관 계장도에 삽입하여 신뢰도흐름도를 개발하였다. 본 신뢰도흐름도는 화학공정의 기본 도면인 공정흐름도, 공정배관 계장도와 마찬가지로 화학공정의 설계, 예방점검 등 설비관리에 효율적으로 이용될 수 있을 것이다.

• 전기학회논문지
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• 제60권3호
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• pp.465-470
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• 2011

Recently fault currents are increasing in a network. It is caused by increase in electric demand and high penetration of distributed generation with renewable energy sources. Moreover, distribution network has become more and more complex as mesh network to improve the distribution system reliability and increase the flexibility and agility of network operation. Accordingly, the fault current will exceed capacity of circuit breakers soon and all the various rational solutions to solve this problem are taken into account. Under these circumstances, superconducting fault current limiter(SFCL) is a new alternative in the viewpoint of technical and economic aspects. This study presents operation processes for a resistive-type of SFCL, and it proposes reliability model for the SFCL. When a SFCL is installed into a network, the contribution of decreased fault currents to failure for distribution equipments can be quantified. As a result, it is expected that a SFCL makes the reliability of adjacent equipments on existing network improve and these changes are analyzed. We propose a methodology to evaluate the reliability in the distribution network where a SFCL is installed considering a reliability model for resistive-type of SFCL and reliability changes for adjacent equipments which are proposed in this paper.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.119-120
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• 2020

In order to establish an evaluation method that can quantitatively evaluate the fire safety of existing buildings in Korea, a stochastic approach is needed to consider the extent of damage in the event of actual fire, along with the operation and installation of facilities. Accordingly, as a basic study for the establishment of fire safety assessment methods for buildings, this study aims to analyze the results of safety inspection and the degree of damage caused by the operation of fire doors and fire shutters in order to derive the reliability of fire doors and fire shutters. As a result, the results of inspection of fire shutters and fire doors and the results of operation using fire statisticians are as follows. As a result of the inspection, the positive rate of fire doors was about 82% and 98% of normal operation was derived from the fire investigation.

• KIEE International Transactions on Power Engineering
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• 제5A권1호
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• pp.9-15
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• 2005

In the operation of distribution systems, DGs (Distributed Generations) are installed as an alternative to extension and the establishment of substations, transmission and distribution lines according to the increasing power demand. In the operation planning of DGs, determining optimal capacity and allocation achieves economical profitability and improves the reliability of power distribution systems. This paper proposes a determining method for the optimal number, size and allocation of DGs in order to minimize the operation costs of distribution systems. Capacity and allocation of DGs for economical operation planning duration are determined to minimize total cost composed with power buying cost, operation cost of DGs, loss cost and outage cost using the GA (Genetic Algorithm).

• 한국ITS학회 논문지
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• 제16권6호
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• pp.112-123
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• 2017

정부의 대중교통활성화 정책과 이용자들의 승용차에서 버스나 지하철로의 수단 전환으로, 대중교통의 정확한 배차시간과 도착시간의 확보가 중요해졌다. 서울시에서 제공하는 버스운행관리시스템(BMS : Bus Management System) 자료를 이용하여, 실시간 버스위치, 배차간격, 운행이력 등의 정보를 알 수 있다. 본 연구에서는 BMS 자료를 이용하여 안전운행을 하면서 정시성도 확보할 수 있는 방안을 제안하고자 한다. 다른 연구와는 다르게, 버스 정류장 사이 구간을 5개의 지점과 6개의 시간으로 나누어, 각각의 시간을 BMS 자료를 이용하여 산정하였다. 또한, 각 시간에 영향을 주는 주된 원인을 살펴보고, 요소별 평균, 표준편차, 변동계수를 이용하여 정류장 별 정시성과 안전성, 이동성을 모두 확보한 버스 노선의 적정 운행시간을 제안하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권2호
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• pp.61-73
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• 2008

Reliability program in one of the most efficient tools for cost saving during the acquisition process including alternatives for design configurations, operation concepts, maintenance concepts. Industrial reliability centers have already equipped with infrastructure such as reliability standards, reliability apparatus. In this study revitalizing plans are proposed to apply industrial reliability technology to national defense technology.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 신뢰성해외전문가초청세미나
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• pp.15-25
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• 2004

Inherent reliability depends on decisions made during design and manufacture. Reliability degrades with age and production rate (or usage level/intensity). System design based on some nominal production rate. Actual production rate can differ-depends on commercial considerations.(omitted)

• 한국산업경영시스템학회:학술대회논문집
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• 한국산업경영시스템학회 2002년도 춘계학술대회
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• pp.195-202
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• 2002

The primary objective of Supply Chain Management (SCM) is to optimize the cash, material and information flow for satisfying customer demands through coordinating the relationship between Supply Chain components such as suppliers, manufacturers, and inventories, etc. By Supply Chain Planning (SCP), operation tasks or goals, should be done in specific due date, are ordered to each SC component for achieving such objective. However, the achievement for operation tasks or goals is affected by uncertainties in SC. In general, reliability theory Is explained as the probability that a product or system will perform its specified function under prescribed conditions without failure for a specified period of time. Therefore, the reliability of SC can be defined as the probability that SC will satisfy customer demands until the specific due date. In this paper, a basic framework to evaluate reliability is respectively proposed as supply chain components, and then a overall framework to estimate the reliability for SC is also proposed.

• 시스템엔지니어링학술지
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• 제5권1호
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• pp.43-48
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• 2009

Korean Tilting trains have been tested on conventional lines since the beginning of 2007 for evaluating its reliability. We achieved some major performance tests which are the maximum operation speed, 180km/h test and the maximum curves increasing speed, over 30 percentage comparing with non-tilling operation train. In order to analysis reliability data of tilting train, we have used the special system engineering frame with interfacing between component suppliers effectively. And also we have developed the data aquisition system which consists of monitor, sensors and depot computer etc. As a results of calculation, until now we realized that the reliability are getting more increasing than starting point of running field test.

• Nuclear Engineering and Technology
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• 제29권6호
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• pp.433-443
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• 1997

In this work, an analytic approach to the dependability of software in the operational phase is suggested with special attention to the hardware fault effects on the software behavior : The hardware faults considered are memory faults and the dependability measure in question is the reliability. The model is based on the simple reliability theory and the graph theory which represents the software with graph composed of nodes and arcs. Through proper transformation, the graph can be reduced to a simple two-node graph and the software reliability is derived from this graph. Using this model, we predict the reliability of an application software in the digital system (ILS) in the nuclear power plant and show the sensitivity of the software reliability to the major physical parameters which affect the software failure in the normal operation phase. We also found that the effects of the hardware faults on the software failure should be considered for predicting the software dependability accurately in operation phase, especially for the software which is executed frequently. This modeling method is particularly attractive for the medium size programs such as the microprocessor-based nuclear safety logic program.