• Title/Summary/Keyword: maintenance & repair

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Optimal Periodic Replacement Policy Under Discrete Time Frame (이산 시간을 고려한 시스템의 교체와 수리 비용 최적화 연구)

  • Lee, Jinpyo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.43 no.1
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    • pp.61-69
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    • 2020
  • Systems such as database and socal network systems have been broadly used, and their unexpected failure, with great losses and sometimes a social confusion, has received attention in recent years. Therefore, it is an important issue to find optimal maintenance plans for such kind of systems from the points of system reliability and maintaining cost. However, it is difficult to maintain a system during its working cycle, since stopping works might incur users some troubles. From the above viewpoint, this paper discusses minimal repair maintenance policy with periodic replacement, while considering the random working cycles. The random working cycle and periodic replacement policies with minimal repair has been discussed in traditional literatures by usually analyzing cases for the nonstopping works. However, maintenance can be more conveniently done at discrete time and even during the working cycle in real applications. So, we propose that periodic replacement is planned at discrete times while considering the random working cycle, and moreover provide a model in which system, with a minimal repair at failures between replacements, is replaced at the minimum of discrete times KT and random cycles Y. The average cost rate model is used to determine the optimal number of periodic replacement.

무작위 초 보유 자원을 이용한 신뢰성 모델

  • Kim, Songkyoo
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2001.10a
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    • pp.199-202
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    • 2001
  • This article deals with stochastic reliability systems that include a repair facility and unreliable machines: the main facility of working and an auxiliary facility of "super-reserve" machines. The number of super-reserve machines are random number with a arbitrarily distribution and working machines break down exponentially. Defective machines line up for repair, whose durations are arbitrarily distributed. Refurbished machines return to the main facility. If the main facility is restored to its original quantity, the repair facility leaves on routine maintenance until all of super-reserve machines are exhausted. Then, the busy period is regenerated. The whole system also falls into the category of closed queues, with more options than those of basic models. The techniques include two-variate Markov and semi-regenerative processes, and a duality principle, to find the probability distribution of the number of intact machines. Explicit formulas obtained demonstrate a relatively effortless use of functionals of the main stochastic characteristics (such as expenses due to repair, maintenance, waiting, and rewards for higher reliability) and optimization of their objective function. Applications include computer networking, human resources, and manufacturing processes.

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A decision support system for diagnosis of distress cause and repair in marine concrete structures

  • Champiri, Masoud Dehghani;Mousavizadegan, S.Hossein;Moodi, Faramarz
    • Computers and Concrete
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    • v.9 no.2
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    • pp.99-118
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    • 2012
  • Marine Structures are very costly and need a continuous inspection and maintenance routine. The most effective way to control the structural health is the application of an expert system that can evaluate the importance of any distress on the structure and provide a maintenance program. An extensive literature review, interviews with expert supervisors and a national survey are used to build a decision support system for concrete structures in sea environment. Decision trees are the main rules in this system. The system input is inspection information and the system output is the main cause(s) of distress(es) and the best repair method(s). Economic condition, severity of distress, distress situation, and new technologies and the most repeated classical methods are considered to choose the best repair method. A case study demonstrates the application of the developed decision support system for a type of marine structure.

A Study on the Construction Methods of Sealer of Injection Type for Leakage Maintenance for Water Leakage and Cracks in Concrete (콘크리트 누수균열의 유지관리를 위한 누수보수용 주입형 실링재 시공방법 연구)

  • Kwon Shi-Won;Oh Mi-Hyun;Kwak Kyu-Sung;Oh Sang-Keun
    • Journal of the Korea Institute of Building Construction
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    • v.6 no.1 s.19
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    • pp.87-91
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    • 2006
  • Since water leakage and cracks are not the source of serious problems such as long-term lowering of performance and durability of a stricture, including damages to operating facilities of a structure, damages to internal finishing materials, exhibition, and goods, and pollution of residential environment, they might have led to development of positive coping skills; however, an instant loss of lives or property due to earthquake, explosion, typhoon, or a fire was indeed neglected. In these days, repair materials for leakage cannot help but being taken in temporary way without any noticeable countermeasure. This kind of repair is socially criticized many times that is defective construction even if this costs a lot. It was not arrange the standard for construction methods of sealer of injection type for leakage maintenance, even it has been used various type of construction methods for leakage part. In conclusion, we suggest that the construction methods of sealer of injection type for leakage maintenance for leakage to establish the leakage repairing technology as increase of structure demand. Therefore, it would be possible to provide a stage-by-stage solution by developing systematic research activities among the industry, schools, and research institutes to spread maintenance management techniques globally through technical solution to water leakage and cracks, acquisition of structural safety with prolonged durability for life cycle, reduction of water leakage repair expense s, and so on.

Repair Cost Estimation Model of the Building Exterior and Outdoor Facilities in Apartment Housing (공동주택 건물 외부공간 및 옥외시설의 공종별 수선비용 산정모델)

  • Lee, Kang-Hee;Chae, Chang-U
    • KIEAE Journal
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    • v.16 no.3
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    • pp.129-135
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    • 2016
  • Purpose: Building figuration is imperative to perceive the its value, environmental clean status and form. Therefore, maintenance activities of the building exterior are required to keep the housing condition and value. Each household should pay the repair cost which is brought out in the future. For this repair cost, the estimation model would needed to forecast and provide the required cost. This study aimed at providing the estimation model of the repair cost, using the repair survey data between the 2011 and 2014 in Seoul. Method: For these, it took various estimation function of repair cost such as 1st function, inverse function and so on. These above functions would be applied into the building exterior and outdoor facilities which figure the building shape and characteristics. Result: Results of this study are shown ; First, among 11 estimation models, the power function has a better statistics and goodness-of-fit than any other models. Second, the estimation model with a variable of household has a pattern in upward to the right. On the contrary, the model with management area is little downward to the right. Both of them are depended on the estimated parameter of the power function and the parameter smaller than 1.

Structural Characteristics of Reinforced Concrete Beam-Column Joints Repaired and Restrengthening (재보수-보강된 철근콘크리트 보-기둥 접합부의 구조특성)

  • Cho, Chang-Ho;Kim, Jeong-Sup
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.2
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    • pp.231-238
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    • 2003
  • Reinforced concrete buildings damaged by earthquake which can be reused can ensure the stability in its structure by repair-restrengthening, but when such a repair-restrengthening is conducted inappropriately or its structural strength is greatly reduced by earthquake again, it should have repair-restrengthening. This study selects beam-column joints which are vulnerable to earthquake as the object of experiment, performs repair-restrengthening after applying the first and the second dynamic loading to the objects of experiment, examines the capacity of restrengthening according to structural characteristics and loading velocity and verifys the validity of repair-restrengthening.

Establishment of the Service Life of the Education Fcilities - Focused on the Roof water-proof and Floor finishings - (교육시설 내용년한 산정 연구 - 옥상방수와 바닥마감재를 대상으로 -)

  • Lee, Kang-Hee;Chae, Chang-U
    • Journal of the Korean Institute of Educational Facilities
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    • v.24 no.6
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    • pp.27-36
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    • 2017
  • Educational facilities have an affect to make a decently learning environment. After constructed, it needs a maintenance plan to keep the performance or function which provide the repair time, repair scope and ratio. But the fundamental data are so insufficient that the field worker can't provide the maintenance plan and has no choice use the other data which concerned with apartment or office building. Above all, the service life is indispensible to make a repair plan because the repair time and scope would be provided within the service life. This study aimed at providing the method to make a service life of component in educational facilities and applying the method into the roof proof and floor finishing. Results are shown that first, it is important to set the $1^{st}$ repair time after constructed. when it proposes the three ways with the probability approach, choice probability model and cumulative cost function. Second, the service life of roof proof is provided with about 35 years. In addition, the service life of the floor finishing is about 40 years. These result would be utilized to conduct the repair plan under the service life.

Determining Major Items of Scheduled Maintenance for Apartment through Case Data: Focused on Improving the Establishment Standard for Long-term Repair Program (사례 데이터 분석을 통한 공동주택 계획수선 주요 항목 도출: 법령 상의 장기수선계획 수립기준 현실화를 중심으로)

  • Song, Sanghoon;Lee, Seok-Je;Park, Seong-Sik
    • Land and Housing Review
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    • v.7 no.1
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    • pp.43-51
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    • 2016
  • The long-term repair program is significant as the execution standard for apartment in repair construction, and provides the basis for effective facility management through appropriation reserve and preventive maintenance. Considering its importance, the government legislates the items, cycle, and ratio for long-term repair. However, the frequent changes, controversies on repair, and difficulties in using appropriation reserve are caused as the items have not been revised on time reflecting up-to-date construction technologies. In order to resolve these problems, it is required to improve the standard by evaluating the appropriateness of repair items throughout the analysis of actual conditions. This study aims to suggest the revision plan for the criteria with the major items based on the status identified by the actual long-term repair programs and historical repair construction data. To do this, the adoption ratios of items to program are reviewed by collecting the real cases of the long-term repair programs. Developing improvement plan was approached in two ways such as "exclusion method" deleting minimum unnecessary items and "selection method" sorting out items with high adoption ratio and evidence of repair in a positive manner. Aa a result, the major items were identified as 118 items and 73 items by exclusion method and selection method respectively from the current 147 items. The outcomes of this study are expected to contribute enhancing the practicality of the standard in that the regulation for long-term repair program should periodically reflect the status of currently applied construction methods and materials.

The Study on Application of Advanced Maintenance and RePairBudgeting Model for Domestic Military Facilities (국방시설에 적합한 선진 유지관리예산모델의 적용에 관한 연구)

  • Park Chan-Sik;Hong Sung-Ho
    • Korean Journal of Construction Engineering and Management
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    • v.3 no.4 s.12
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    • pp.123-131
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    • 2002
  • The M&R(Maintenance & Repair) budgeting system for domestic military facilities based incremental budgeting model has caused many problems due to the difference between M&R requirement and budget, so military facility become early deterioration. this study proposes the application method of foreign M&R budgeting model for domestic military facility to improve current M&R budgeting system. In order to investigate the current status and problem of M&R budgeting system, this study reviewed various literature related characteristics and types of the foreign M&R budgeting model. The interview was performed for domestic military facility official. The model would greatly improve the current M&R budgeting process for the domestic military facilities.

Prediction of UDPSC Bridge's Maintanence Cost based on Life Cycle Cost Analysis (LCC 분석에 기초한 UDPSC 교량의 유지관리비 예측에 관한 연구)

  • Shim, Bo-Hyun;Lee, Heung-Chol;Woo, Sung-Kwon
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.638-641
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    • 2006
  • In this paper, A calculating cost method of maintenance and repair for bridge which is built up by new construction technique named Up-Down Precast Concrete(UDPSC). After 2000, 109 Bridges which are using UDPSC technique have been built up, 37 bridges's construction work are processing, and 194 designs are presented for construction. Because this technology has developed recently, there are few field data for analyzing the maintenance and repair cost. Therefore, the maintenance and repair cost is computed using Construction and Transportation Ministry's guide line for computation and former research's data.

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