• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.999-1007
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• 2009

This paper considers the optimal periodic preventive maintenance (PM) policy following the expiration of free-repair warranty. We assume that two periodic PM models with random maintenance quality which were proposed by Wu and Clements-Croome (2005) and Jung (2006b), respectively. Given the cost structure to the user during the cycle of the product, we derive the expressions for the expected cost rate per unit time. Also, we obtain the optimal PM number and the optimal PM period by minimizing the expected cost rate per unit time. The numerical examples are presented for illustrative purpose.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.775-784
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• 2011

In this paper, we consider the periodic preventive maintenance model for repairable system following the expiration of non-renewing free replacement-repair warranty (NFRRW). Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• Journal of the Korean Institute of Educational Facilities
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• v.16 no.1
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• pp.33-41
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• 2009

The purpose of this study is to provide a basis for calculation of school operation fees for normal functioning of the school facilities, and facility maintenance and repair cost through their life spans, considering remodeling of the facilities and changes of their functions. This study analyzes maintenance and repair records during the three years from 2003 to 2005 in primary, middle and high schools in Incheon Metropolitan city and also the facility management and operation expenditure of the same schools in the city during the year of 2005, and presents quantified unit cost of each item according to the area, the age of the facilities, and the number of classroom, student, and lessons given. The calculation can be a basis for both BTL school facility managers and the general school facility mangers to budget school facility maintenance cost appropriately and the quantity of energy, water, electricity, and telephone fees calculated here can be a criteria for the managers to check the normal maintenance of their facility.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.63-66
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• 2007

In recent years, the concrete cracks in most construction field have been widely presented and developed. Also it is well known the repair cost of the concrete cracks have been rapidly increased in Korea. So the concrete crack expert system was developed to minimize the repair cost and to support the field engineer. The feature of this web based system for diagnosing the causes of concrete cracks is comprised of comfortable user application.

• International Journal of Reliability and Applications
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• v.12 no.1
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• pp.41-48
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• 2011

This paper considers the maintenance model suggested by Jung and Park (2010) to adopt the Bayesian approach and obtain an optimal replacement policy following the expiration of NFRRW. As the criteria to determine the optimal maintenance period, we use the expected cost during the life cycle of the system. When the failure times are assumed to follow a Weibull distribution with unknown parameters, we propose an optimal maintenance policy based on the Bayesian approach. Also, we describe the revision of uncertainty about parameters in the light of data observed. Some numerical examples are presented for illustrative purpose.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.149-150
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• 2012

According to the increase of demand of the deteriorated building. The interest of the building's maintenance is continually increased, so studies about how to increase building's stability & prolonged life span are increased. This study's purpose is to maintain building's function, so we suggest a protocol type system of UI to estimate reasonable planning of demand of repair & replacement and to distribute budget.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.87-88
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• 2016

In order to assess the design value of engineering work from the point of view of LCC (Life Cycle Cost) in Korea, it is mandatory for all construction works that the total construction costs are over 10 billion won. The LCC includes initial construction costs, maintenance & operation costs, energy costs, end-of-life costs, and so on. Among these, the portion for maintenance & operation costs for a building is sizeable, as compared to the initial construction costs. Furthermore, the paradigm for construction industry has rapidly shifted from 2D to BIM, which includes design planning and data management. However, the study of BIM-based LCC analysis is not adequate today, even though all domestic construction projects ordered by the Public Procurement Service have to adopt BIM. Therefore, this study suggests a methodology of BIM-based LCC analysis that is particularly focused on repair and replacement (R&R) cost. For this purpose, we defined requirements of calculating R&R cost and extracted X from the relevant IFC data. Thereafter, we input them to the ontology of calculating the initial construction costs to obtain an objective output. Finally, in order to automatically calculate R&R cost, mapping with R&R criteria was performed. We expect that our methodology will contribute to more efficiently calculate R&R cost and, furthermore, that this methodology will be applicable to all range of total LCC. Thus, the proposed process of automatic BIM-based LCC analysis will contribute to making LCC analysis more fast and accurate than it is at present.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.139-142
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• 2003

As composite materials are gaining wide acceptance in aircraft structure, repair of damaged composite is becoming an important issue. The issues in composite repair include high cost, material interchangeability, water ingression, and structural integrity. To address these problems, researchers have studied on the composite repair in various aspects. In this paper, an Internet-based advisory service (called Repair Advisory Service, RAS) for composite repair is proposed to increase efficiency for repair process. In the RAS system the web browser is used as its user interface, which provides easy access to the service. The RAS server provides web-based tools for failure prediction, Structural Repair Manual (SRM), automated prepreg cutting process, material properties, inventory and knowledge base. The computer codes implemented for repair design estimate the tensile failure and shear failure of repaired structures. The prediction of failure is based on the maximum strain criterion for tensile failure while elastic-perfect plastic shear failure model is applied for interfacial failure. The OEM's SRM is provided in the PDF format for viewing and searching by web browsers instead of looking up paper version SRM. The knowledge base in this site offers a room to share and distribute ideas, memos, publications, or suggestions from the repair engineers. The fabrication tool of RAS reads repair geometry from engineers then generates a CNC toolpath to cut prepreg patches. The RAS service is open to public and available at http://nano.gsnu.ac.kr/. Broad feedback from field technicians and engineers is welcome to improve the usefulness of RAS.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.19-24
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• 2014

This study, the exchange value of the car after the repair, which affects the valuation elements and repair characteristics factors were investigated. Based on this specific accident damaged condition of the car, repair range, repair methods, repair costs, market transactions, taking into account the vehicle's depreciation appraisal method is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.1
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• pp.205-212
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• 2002

The deterioration rate of concrete structures in urban area is accelerated due to rapid urbanization and environmental pollution. Repair materials and methods newly introduced in Korea should be investigated whether they are appropriate for the urban environment in Korea. The creek concrete structures are exposed in severe environmental condition than others. Based on these background in mind, the study is focused on evaluation of performance on repair materials used to rehabilitate creek concrete structures. To evaluate the performance of repair materials, four kinds of repair materials were selected based on polymer emulsion. This experimental study was conducted on fundamental performance such as setting time, compressive strength, bending strength, bonding strength, thermal expansion coefficient, and durability performance such as chloride diffusion, carbonation, chemical attack, and steel corrosion rate. On the basis of this study, the optimal repair material which is proper to the environment condition can be selected and service life of creek concrete structures can be extended. As a result, the life cycle cost can be reduced and the waste of material resources will be cut down.