• 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.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.153-159
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• 2018

Many researches have been carried out on carbonation, a representative deterioration in underground structure. The carbonation of RC (Reinforced Concrete) structure can cause steel corrosion through pH drop in concrete pore water. However extension of service life in RC structures can be obtained through simple surface protection. Unlike the conventional deterministic maintenance technique, probabilistic technique can consider a variation of service life but it deals with only normal distributions. In the work, life time-probability distributions considering not only normal but also log distributions are induced, and repair cost estimation technique is proposed based on the induced model. The proposed technique can evaluate the repair cost through probabilistic manner regardless of normal or log distribution from initial service life and extended service life with repair. When the extended service life through repair has log distribution, repair cost is effectively reduced. The more reasonable maintenance strategy can be set up though actual determination of life-probability distribution based on long term tests and field investigations.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.83-94
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• 2022

The number of public rental housing has increased according to the government's 「Housing Welfare Roadmap (2017)」, and facility maintenance costs for the demand of improvement of performance and residential standards due to the aging of long-term public housing are significantly increasing. Consequently, the financial burden of public housing rental business for maintaining stocked housing is aggravated. However, there is a lack of objective data to analyze the size of the maintenance costs that are executed by the type of repair work, and the elapsed years of the aged long-term public rental housing. This study analyzes the execution status of 33 long-term public rental housing complexes located in Seoul for 14 to 28 years of elapsed years based on the data of maintenance costs. In addition, this study proposes a model to predict the maintenance costs by elapsed years by dividing 'Long-term Repair Plan Work and Government-Funded Project [Y₁]', 'Planned Repair Work and General & Unplanned Repair Work [Y₂]', and 'Total maintenance costs [Y₃]'. It is intended to be used as basic data for the establishment of the maintenance plan at the stage of setting up the budget and the establishment of the sustainable operation plan for public rental housing

• 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.

• 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.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.861-872
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• 2021

An efficient cost management is important for the domestic social overhead capital(SOC) based on a long lifecycle after 30 years since completion. Maintenance in South Korea have had the restrictions of consistency and suitability of decision-making by the establishment of a budget plan based on the company estimate and repair and reinforcement methods determined by the inspection and diagnosis engineers' subjective determination for each facility. To resolve this issue, the Korea Institute of Civil Engineering and Building Technology is currently in development of a methodology to propose an optimum maintenance method according to the damage of components by artificial intelligence. This study has deduced the primary factors by analyzing information generated during bridge maintenance and management as a prior step for the development of technologies, and conducted a preliminary analysis to select the optimum artificial intelligence technology.

• 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.

• 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.

• The Journal of Sustainable Design and Educational Environment Research
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• v.9 no.2
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• pp.1-8
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• 2010

This study is to present an engineering solution for the repair frequency and repair rates of a building. The existing data for the repair frequency and repair rates are used to draw the probability distribution for the generalized repair frequency and repair rate in a building. The suggested methodology can be widely used for most buildings to estimate the legal repair frequency and repair rates. Also, the methodology can be applied to resolve the risks on the maintenance costs in LC (Life Cycle) plans or LCC (Life Cycle Cost) analysis. As the future studies, there are the multiple regression analysis including the parameters on incurred costs and the decision methods on efficient repair and replacement.

• 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.