• 대한기계학회논문집A
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• 제39권11호
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• pp.1169-1174
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• 2015

위험도 평가 기술은 주로 플랜트의 많은 운영설비 중 대형사고나 피해를 유발할 수 있는 위험설비를 선별하는 목적으로 개발되었다. 현재 발전소에 설치되어 있는 설비관리시스템에는 초기 버전의 위험도 평가 모듈이 설치되어 있으나 문진 위주로 구성되어 통계적 기법에 기반을 둔 고장 확률 평가보다는 평가자의 주관적인 판단에 따라 평가 결과가 좌우되었다. 또한 발전회사 서버에 기반하였기 때문에 평가자가 공간 및 시간의 제약을 받을 수 밖에 없고 현장 활용에 한계가 있었다. 본 논문에서는 문진 대신 해석적 분석을 이용한 기본 고장확률을 계산하고 현장 검사 결과 및 검사 효용도를 분석할 수 있는 독립형 위험도 평가 소프트웨어를 개발하였다. 독립형으로 현장 운용이 가능하며 최적 정비주기 예측 및 현장검사 결과에 대한 입출력 기능이 있기 때문에 정비에 직접 참여하는 현장 사용자뿐만 아니라 발전 설비의 수명연장 및 교체를 결정해야 하는 엔지니어에게 유용한 정보를 제공할 것이다.

• 플랜트 저널
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• 제8권2호
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• pp.70-81
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• 2012

The study aims to supplement facility management plan and safety regulations & standard of oil pipeline by searching and reviewing related regulation & standard inside and outside of the country. Korean regulation & standard is reviewed based on harbor and fishery design standard of the ministry of maritime affairs and fisheries, general technology standard of oil pipeline safety regulation, gas excavation construction and safety maintenance indicator of Korea gas corporation. Global regulation & standard is reviewed based on U.S standard inspection for offshore pipeline and Europe/Mexico standard inspection for offshore pipeline. The contents of offshore pipeline installation is inserted into pipeline sector for objected facilities of safety inspection regulation & standard and, the standard of safety inspection for offshore pipeline is newly presented into pipeline maintenance part of the planning facilities management with its inspection period and method.

• Journal of applied mathematics & informatics
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• 제41권6호
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• pp.1155-1171
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• 2023

This paper investigates a non Markovian M/G/1 queue with retrial policy, different kind of service rates as well as unsatisfied clients which is inspired by an example of a transmission medium access control in wireless communications. The server tends to work continuously until it finds at least one client in the system. The server will begin its maintenance tasks after serving all of the clients and if the system becomes empty. Provisioning periods in regular working periods and maintenance service periods should be evenly divided. Using supplementary variable technique, the amount of clients in the system as well as in the orbit were found. Further few performance measures of the system were demonstrated numerically.

• 한국철도학회논문집
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• 제4권4호
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• pp.138-146
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• 2001

For the purpose of the effective maintenance of surface irregularities of rail, this paper investigates the rail service life to a bending fatigue failure of welding parts of rail on the slab track by the structures laboratory testing to derive S-N curves, a GTDAP(General Track Dynamic Analysis Program) to calculate the stresses and a modified Miner's rule to predict a fatigue life. The useful guides for maintenance of rail welded parts on the slab track are proposed in terms of a grinding period and the depth of rail surface irregularities. This study also proposed the guides for maintenance of rail welded part on the ballast track. The effects of fatigue service lives are compared one another.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.230-231
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• 2015

Recently, although researching and developing of safety and maintenance on domestic infrastructure facilities in KOREA are important, there has been very little research regarding on a comprehensive and integrated survey of actual condition. Therefore this study asserts the necessity of the survey process of actual condition by period planning(short-term, middle-term, long-term). The purpose of this study is to investigate current situation and to suggest the whole process method, and to establish survey process of actual condition on domestic infrastructure facilities.

• 한국구조물진단유지관리공학회 논문집
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• 제19권3호
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• pp.64-72
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• 2015

고속도로교량을 위한 위험도기반점검주기를 제안하였다. 고속도로 교량유지관리시스템에서 얻은 상태데이터를 분석하여 교량상태 열화에 영향을 주는 위해성인자를 찾았다. 그러한 인자와 상태열화사이의 특정한 상관성을 찾았다. 이들을 이용하여 위해성점수를 평가하는데 이용하였다. 여러 가지 위해성 인자들을 종합하여 최종 위해성을 높음, 보통, 낮음의 세 단계로 구분하였다. 취약성은 교량의 현재상태로 평가하였다. 위험도행렬을 점검주기를 위해 제안하였다. C, D, E등급 교량의 점검주기는 현행대로 유지하였다. 그러나, 보통과 높음으로 위해성이 평가된 A 및 B 등급교량은 점검주기를 최대 6년까지 연장하였고 최소주기는 현행과 같이 3년으로 하였다. 위험도 평가에 따라 점검주기를 보정하므로써 평균 점검인력을 27% 절약할 수 있었다.

• 품질경영학회지
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• 제17권1호
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• pp.1-10
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• 1989

In general, the characteristics of components which consist of multi-component system can not be the same. This paper proposes a maintenance model of multi-component system considering the characteristics of each component. In this paper, multi-component system is divided into three components-critical unit, major unit and minor unit, respectively. This paper determines the optimal replacement time of the system which minimizes total maintenance cost, optimal replacement period of major unit and initial stock quantity of minor unit within this optimal replacement time. Numerical examples are shown when the failure times of each unit have gamma distribution.

• 한국구조물진단유지관리공학회 논문집
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• 제6권2호
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• pp.127-133
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• 2002

Most structures are constantly influenced by repeated weathering phenomena and load action during a period of its utilization, and their component materials become superannuated and their design performance becomes slowly lost. Therefore, it is thought that it is necessary to develop the online monitoring system that can make a great contribution to the maintenance management and disaster prevention of the building structure by sensing any slight change of the entire structure regardless of its inside and outside. Especially, this study was intended to explain the entire system of the online structure by interpreting welded built-up H-beams, of structural steel members having many advantages in terms of the qualities of structural materials, through limit state design, and presenting the basic plan to apply it to the structure.

• 한국전문물리치료학회지
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• 제3권1호
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• pp.73-79
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• 1996

Photochemotherapy(UVA with 8-methoxypsoralen) was given to 30 patients with systemic psoriasis. The results of clearing and long-term(6-month) interval maintenance were reported. Clearing requirements were in general similar to these reported by Melski and Burger. The skin of the 14 patients (46.6%) recovered good skin condition by a once weekly maintenance dose. This result was better than that reported by other authors. 1. During initial treatment period, average number of treatment was 27.3 and average duration treatment was 24.8 weeks. 2. The factors to quit treatment were motion decrease, moving to the remote area, complications, etc. 3. Number of patient who received maintenance treatment was 14. 4. The complications reported from the patients were hyperpigmentation, nausea, headache, pruritis, vomiting, gastritis.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.719-726
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• 2005

The optimal design was performed for the bridge superstructure composed of steel box girders and concrete deck considering life cycle cost. The service life of the superstructure was estimated, after load carry capacity curves for steel girder and concrete deck were derived on the basis of condition grade curves and maintenance histories. The object function was determined as life cycle cost, including initial cost, total maintenance cost, disposal cost and user cost, for a period of the estimated service life. The optimal design of the superstructure was performed for the various service lifes. The annual costs were used to compare calculated results and to get the most economical design. Also this paper presents reasonable idea for the use of user cost with uncertainty.