• 교육녹색환경연구
• /
• 제17권2호
• /
• pp.38-47
• /
• 2018

본 연구는 안전성, 노후도, 경제성 등 시설 여건을 종합적으로 고려하여 개선이 필요한 중장기적인 사업물량 및 사업예산 규모를 추정할 수 있도록 하기 위해 국가수준의 시설개선 기준(수선주기)을 설정하여 체계적인 시설개선계획 수립을 통한 적정수준의 교육환경 확보에 기여할 수 있도록 하는 것을 주목적으로 한다. 적정 수선주기는 기본적으로 최근 2년간 교육청에서 실제 집행한 교육환경개선사업의 실적자료를 분석하여 직전 보수년도와 사업시행연도를 근거로 수선주기 기초자료를 산출하였다. 이를 근거로 17개 시도교육청 실무자를 대상으로 델파이 조사를 실시하여 시도교육청의 의견을 수렴하였으며 최종 적정 수선주기는 관련규정과 실적자료, 델파이조사 결과를 종합적으로 검토하여 설정하였다.

• Steel and Composite Structures
• /
• 제27권5호
• /
• pp.633-646
• /
• 2018

This study investigated the seismic performance of a hybrid damper composed of a steel slit plate and friction pads, and an optimum retrofit scheme was developed based on life cycle cost. A sample hybrid damper was tested under cyclic loading to confirm its validity as a damping device and to construct its nonlinear analysis model. The effectiveness of the optimum damper distribution schemes was investigated by comparing the seismic fragility and the life cycle costs of the model structure before and after the retrofit. The test results showed that the damper behaved stably throughout the loading history. Numerical analysis results showed that the slit-friction hybrid dampers optimally distributed based on life cycle cost proved to be effective in minimizing the failure probability and the repair cost after earthquakes.

• 한국안전학회지
• /
• 제24권5호
• /
• pp.48-56
• /
• 2009

This paper presents the procedure for the optimal design of a PSC-I girder bridge considering life cycle cost (LCC). The load carrying capacity curves for the concrete deck, PSC-I girder and $\pi$-type pier were derived and used for the estimate of service lives. Total life cycle cost for the service life was calculated as sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The advanced First Order Second Moment method was used to estimate the damage cost. The optimization method was applied to the design of PSC-I girder bridge. The objective function was set to the annual cost, which is defined by dividing the total life cycle cost by the service life, and constraints were formulated on the basis of Korean Standards. The optimal design was performed for various service lives and the effects of design factors were investigated.

• Journal of Preventive Medicine and Public Health
• /
• 제29권3호
• /
• pp.597-607
• /
• 1996

Genotoxic agents can induce various DNA lesions. DNA-Protein Crosslinks(DPCs) were known as the important DNA lesions which could impair gene expression because DPCs had a high probability of resisting repair and persisting through cell cycle. This repair resistance of DPCs could have biological significance but had not been evaluated clearly yet. Most of the studies that have evaluated the repair of DPCs only compared the extent of DPCs repair with other DNA lesions. We injected $K_2CrO_4$, a genotoxic agent, into Sprague-Dawley rats intraperitoneally(5mg/kg) and isolated blood lymphocytes 12 hours later. These lymphocytes were cultured in the mitogen added growth media and mitogen free media separately. The degree of the repair of DPCs was monitored for 4 days by the K-SDS assay. 4 days later, the amount of DPCs decreased by 4.6% in the mitogen added media high increased by 10.9% in the mitogen free media. These results showed that DPCs induced by $K_2CrO_4$ were not repaired easily and the DPCs were biologically significant DNA lesions. We thought the decrease of DPCs in the mitogen added media was not due to the repair of DPCs, but from the increase of normal cell proliferation. Therefore, it is very important to consider the proliferation of normal cells when estimating the repair of DPCs.

• KIEAE Journal
• /
• 제13권6호
• /
• pp.129-136
• /
• 2013

The rental housing has played a key role to supply a decent living space for the low-income households. The owner of the rental housing should maintain and manage the building physical condition. On the other hand, rents should use the housing without any damage and pay a certain fare for the rent. A rent is classified into two types : private and public. The public rent is mainly to supply a living space for non-available home owner with a low-rent fare. Many of public rent are built and supplied by the public institution or local government. The supplier would take a responsibility to maintain the building and components, reflected by the maintenance plan and repair scope. In this paper, it aimed at providing the repair time in building components of the public rental housing such as lighting, electrical cable, paintings and etc.. The repair time is analyzed with three calculation methods which are solved by the probability and empirical approach. Results are as follows : First, the repair time of the electrical facilities are maintained with 11yr, 10yr and 7 in permanent, public and redevelopment rent respectively. The roof proof has a repair time with 14yr, 11yr and 8 in permanent, public and redevelopment rent housing respectively. Second, Most of the components has a prior length of the repair time in permanent, public and redevelopment rent sequently. There is a difference in repair time according to the rental types. Therefore, it would continue to research the difference in aspect of the living style, building physics, living consciousness and etc.

• 한국주거학회논문집
• /
• 제16권5호
• /
• pp.67-74
• /
• 2005

The performance of building should be deteriorated with time while the building would maintain and manage the function and performance to get a living condition. For the efficient maintenance of the building, the repair cycle would be provided and applied during the service-life time. The service-life time of the building components would be needed to determine the repair time and the repair scope. The service-life time of the building components would be calculated with the 1st repair time and the recovery rate of the performance, considering the recovery rate after repaired. In this paper, the 1st repair time would be estimated with the normal probability distribution, choice probability and 3rd quadratic function. The recovery rate of the building components assumes various level according to the research target and utility area. The results of this study are as follows ; first, most of the components of the building work would range about 30 years in the service-life time and the components of the mechanical works range from 28 years to 37 years, those of the electrical works would be about 31 years.

• Communications for Statistical Applications and Methods
• /
• 제18권6호
• /
• pp.697-705
• /
• 2011

본 논문에서는 수리가 가능한 시스템에 대하여 무료 재생교체-비재생수리보증이 종료된 이후의 최적의 교체정책을 제안한다. 이를 위해서, 무료재생교체-비재생수리보증을 정의하고, 사용자 측면에서 무료재생교체-비재생수리보증이 종료된 이후의 보전모형을 고려한다. 최적의 보전정책을 결정하기 위한 기준으로는 사용자 측면의 단위시간당 기대비용을 사용하는데, 이러한 단위시간당 기대비용을 구하기 위해서 사용자측면의 기대순환길이와 총기대비용을 각각 유도한다. 끝으로 본 논문에서 제안된 무료 재생교체-비재생수리 보증이 종료된 이후의 최적의 교체정책을 설명하기 위해서 수치적 예를 살펴본다.

• International Journal of Computer Science & Network Security
• /
• 제22권4호
• /
• pp.261-273
• /
• 2022

Over the last decade, the scientific community has been actively developing technologies for automated software bug fixes called Automated Program Repair (APR). Several APR techniques have recently been proposed to effectively address multiple classroom programming errors. However, little attention has been paid to the advances in effective APR techniques for software bugs that are widely occurring during the software life cycle maintenance phase. To further enhance the concept of software testing and debugging, we recommend an optimized automated software repair approach based on hybrid technology (OAPR-HOML'1). The first contribution of the proposed OAPR-HOML'1 technique is to introduce an improved grasshopper optimization (IGO) algorithm for fault location identification in the given test projects. Then, we illustrate an opposition learning based artificial neural network (OL-ANN) technique to select AST node-level transformation schemas to create the sketches which provide automated program repair for those faulty projects. Finally, the OAPR-HOML'1 is evaluated using Defects4J benchmark and the performance is compared with the modern technologies number of bugs fixed, accuracy, precession, recall and F-measure.

• 한국전자거래학회:학술대회논문집
• /
• 한국전자거래학회 2001년도 e-Biz World Conference
• /
• pp.499-520
• /
• 2001

◈ B2B e-commerce is set to grow significantly in the next 5 years ◈ There is a growing trend towards leveraging the information asset to win new business in the Maintenance, Repair and Overhaul (MRO) market ◈ After-market service is forecast to be a significant element of the B2B market ◈ Existing standards do not fully address the product support requirement ◈ PLCS standards will allow support information to be aligned with the changing product over its entire life cycle ◈ Adoption of PLCS standard will lead to reduced operating costs and increased product availability.(omitted)

• Journal of applied mathematics & informatics
• /
• 제8권1호
• /
• pp.199-212
• /
• 2001

We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.