• Journal of the Korean housing association
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• v.16 no.5
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• pp.67-74
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• 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.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.717-723
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• 2008

Many of the domestic PC manufactures and professional PC repair shops are suffering from lack of efficient diagnostic database systems or CAD tools for diagnosis and repair of PCs. In order to solve this problem, a new diagnostic database system for PC maintenance and repair is presented in this paper. We can perform accurate and rapid diagnosis for the PCs with software and hardware troubles by using proposed database system and thus the number of customers who are satisfied with service results are to be increased. Furthermore our research outputs make it possible the experts in PC repair field accumulate maintenance techniques and enhance the reliability of performance evaluated by customers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.69-77
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• 2009

An underwater structure is made to put with serious damage state by special environmental factors. If this damage phenomena persist, as for the structure, it is generated a structural serious problem because of the corrosion of a reinforcing bar and the loss of the concrete cut end. Repair work of an underwater structure is very harder than repair work in land, and it is actual that certification about a maintenance effect is uncertain. And the existing repair method is applied to a structure damaged with you without verification of a repair effect by a foreign reward and experience. In this study, a repair method about an underwater structure was proposed and observed a behavior characteristic and interface failure of an specimens. and comparison analyzed an effect of a proposed maintenance method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.247-254
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• 2019

Recently, in designing military equipment, considerable attention has been paid to maintaining operations, including reliability, maintenance, and maintenance time of equipment, from the early stages of development. Therefore, both users and developers stress the importance of design considering the maintenance time. This study evaluated the specific methodologies for predicting the realistic maintenance time, such as the access complexity of equipment, other than the standard maintenance time provided by the conventional method mil-hdbk-470a at the beginning of the design, and applied the time conversion factor using a measure of the maintenance complexity. In addition, the actual maintenance time reflecting the actual maintenance time of the developed equipment and the time-conversion factor applied was compared/verified to confirm the reliability of the data. In a study to set a target for repair and the repair of equipment design in the future, it is expected that the maintenance time of equipment that fails to measure the maintenance time for the initial actual equipment will be reflected as a more realistic time. Moreover, activities, such as research and design reflection activities, will be performed to reduce the maintenance time, operational maintenance cost, etc.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.176-181
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• 2018

Concrete structures are degraded physically and chemically due to various reasons after construction. Because the deterioration of concrete structure reduces the service life, reasonable repair and maintenance techniques are needed. Recently, in order to efficiently repair concrete structures, many researches on hybrid repair materials having improved adhesion performance have been carried out actively. In this study, we developed a hybrid repair material containing rapid hardening cement, PVA powder, nylon fiber, and latex to improve adhesion and water-tightness of existing concrete. The compressive strength, drying shrinkage and the adhesion strength test were carried out to evaluate the performance of the repair material. In addition, the flexure bond performance was evaluated before and after repair. From the results, the bending strength was 110% ~ 150% in all specimens except for the specimen containing only the rapid hardening cement, and all the specimens behaved with the existing concrete in the crack pattern generated by the bending strength.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.95-103
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• 2023

Aircraft engine parts repair is a field belonging to the lowest level in the hierarchy of the aircraft industry, and it is marginalized in terms of research, compared to aircraft manufacturing or maintenance that belong to the upper level. On the other hand, in 2019, Korean Air's Powerplant Maintenance Center paid USD $130 million to foreign countries for engine parts repair, making it an industry with great need for localization. To achieve the goal of localizing engine parts repair, a certification system is needed that can perform independent repairs based on the development of repair technology, aligning contractual relationships with engine manufacturers, and free from dependence on engine manufacturers or foreign repair companies. The purpose of this study is to provide a basis for subsequent research to secure an actual certification system by suggesting the need for securing such a certification system.

• Journal of the military operations research society of Korea
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• v.24 no.1
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• pp.98-109
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• 1998

This study develops a maintenance strategy for a reparable 2-unit standby system. The maintenance strategy implies the waiting time to call the repair facility when the unit-1 fails. Almeida and Souza set up the multi-attribute utility function consisting of system availability and repair cost for several maintenance strategies and decide the optimal maintenance strategy that maximize the expected value of the utility function. We decide the optimal maintenance strategy satisfying the following two criteria about the utility function : maximum variance using Almeida and Souza's utility function. It both criteria are not satisfied at the same time for every strategies, the strategy maximizing the lower confidence limit for expected utility function is regarded as an optimal one.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.286-289
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• 2004

The purpose of this study is to investigate maintenance states and problems analysis of permanent rental housing. The research method of this study includes a survey of maintenance states and an interview with facility managers who have enough practical experience. The results of this study are as follows: (1) the repair rates for the items which are within the required maintenance cycle are investigated $25\%$ on average. (2) the current regulation of maintenance cycles and repair rates are not adequate to Permanent Rental Housing.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.495-500
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• 2001

After the completion of an apartment housing project, deterioration of building materials will commence over time. Building maintenance consists of short-time and long-term repair projects. A long-term repair plan for organized maintenance management should be developed and implemented to maintain the longevity of the building. When forming such a plan, one should carefully predict when each part of the building will need repairs and how often subsequent repairs of each part will occur. The plan should be based on these predictions. Many apartment buildings in Korea have poor long-term maintenance management plans. This is because many of these plans are developed as mere legal formalities rather than as serious attempts to maintain the longevity of buildings. In this study, the materials used in the construction of each part of an apartment building we selected are taken into account to predict when the repairs will be required and how frequently subsequent repairs will be required. Furthermore, We suggest a long-term maintenance management plan for elongation so that apartment house managers can use to periodically check, diagnose, and replace old or malfunctioning parts using a web-based maintenance calender.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.2
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• pp.267-275
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• 2023

As aged infrastructures have been increased, the importance of accurate maintenance costs and proper budget allocation for infrastructure become prominent under limited resources. This study proposed a mapping algorithm between representative defects, repair methods, and the estimated maintenance costs for concrete bridges. In this regard, using BMS (Bridge Management System) data analysis, bridge repair methods were classified and matched with defects according to their locations, types, and sizes. In addition, the maintenance costs were estimated based on the amount of work-load and quantity per unit using CSPR (Cost Standard Production Rate). As a result, the level of accuracy was an average of 85.1 % compared with the actual bill of quantity for Seoul bridge maintenance. The accuracy of maintenance costs is expected to be enhanced by considering the various site conditions such as pier height, extra charge conditions, additional equipment, etc.