• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.3
• /
• pp.78-89
• /
• 2022

The purpose of this study was to propose useful suggestion by analyzing preventive replacement policy under which there are minor and major failure. Here, major failure is defined as the failure of system which causes the system to stop working, however, the minor failure is defined as the situation in which the system is working but there exists inconvenience for the user to experience the degradation of performance. For this purpose, we formulated an expected cost rate as a function of periodic replacement time and the number of system update cycles. Then, using the probability and differentiation theory, we analyzed the cost rate function to find the optimal points for periodic replacement time and the number of system update cycles. Also, we present a numerical example to show how to apply our model to the real and practical situation in which even under the minor failure, the user of system is not willing to replace or repair the system immediately, instead he/she is willing to defer the repair or replacement until the periodic or preventive replacement time. Optimal preventive replacement timing using two variables, which are periodic replacement time and the number of system update cycles, is provided and the effects of those variables on the cost are analyzed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.1
• /
• pp.32-39
• /
• 2018

Repairing timing and the extended service life with repairing are very important for cost estimation during operation. Conventionally used model for repair cost shows a step-shaped cost elevation without consideration of variability of extended service life due to repairing. In the work, RC(Reinforced Concrete) Column is considered for probabilistic evaluation of repairing number and cost. Two mix proportions are prepared and chloride behavior is evaluated with quantitative exterior conditions. The repairing frequency and cost are investigated with varying service life and the extended service life with repairing which were derived from the chloride behavior analysis. The effect of COV(Coefficient of Variation) on repairing frequency is small but the 1st repairing timing is shown to be major parameter. The probabilistic model for repairing cost is capable of reducing the number of repairing with changing the intended service life unlike deterministic model of repairing cost since it can provide continuous repair cost with time.

• Journal of the Korean housing association
• /
• v.14 no.4
• /
• pp.11-19
• /
• 2003

This study intends to predict prospective defects and establish the plan of Preventive Maintenance through research and analysis of defect occurrences and their repair costs in the public equipment of ‘H’ apartment house from 1998 to 2001. According to results of the analysis, more than 90% of defects and their repair costs for 4 years of the building have occurred in heating, hot water and water supply equipments. In case of specific classification in each equipment, more than 60% of defects were found at hot water pipes and heating pipes, and their repair costs covered more than 60% of the total defect costs. After two repairs by ‘Preventive Maintenance’ had been performed in the year 1998, total defects and defects of each equipment each yew have increased in number from 1999 to 2001. But total repair costs and repair costs of each equipment have not increased as time has gone by, because repair costs have relationship with the price of materials and labor, the part of defect and the scale of repair.

• Journal of Korean Society for Quality Management
• /
• v.31 no.1
• /
• pp.142-147
• /
• 2003

Burn-in is a widely used method to eliminate the initial failures. Preventive maintenance policy such as block replacement with minimal repair at failure is often used in field operation. In this, paper burn-in and maintenance policy are taken into consideration at the same time. The cost of a minimal repair is assumed to be a non-decreasing function of its age. The problems of determining optimal burn-in times and optimal maintenance policy are considered.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2010.05a
• /
• pp.235-236
• /
• 2010

Since many structures in the sea environment are damaged by chloride, appropriate repair strategy is required. Therefore in the paper, optimum period for the RC structure's repair is calculated with consideration of economic efficiency. Moreover, when the concrete members are repaired with the other material such as polymer mortar forr section restoration, their expected service life also calculated to predict more accurate repair period during the life span.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.20 no.43
• /
• pp.99-107
• /
• 1997

We consider a multiechelon repairable-item inventory system where several bases are supported by a central depot and the external repair facilities. Unlike METRIC- based models, there are only a finite number of repair channels at each base, central depot and the external repair facilities. It is desired to find repair capacities and spares level which together guarantee a specified service level at minimum cost. Closed queueing network theory is used to model the stochastic process. The purpose of this paper is to derive the steady-state distributions of this system.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.2
• /
• pp.31-38
• /
• 2016

In a construction project, the portion for maintenance costs for a building is considerable compared to the initial construction cost. As such, Life Cycle Cost (LCC) analysis is being increasingly utilized to assess the design value of engineering work in Korea. Additionally, the Public Procurement Service in Korea announced that it will be mandatory for all domestic construction projects to adopt BIM. Furthermore, the paradigm for architectural design has shifted from 2D to 3D, and to BIM, which includes a data management system. Within this background, however, there is currently no adequate BIM-based LCC analysis software and the requirements of cost estimation for repair and replacement cost for a building is not completely adequate in BIM tools such as Revit and Archicad. Therefore, this study suggests a process of cost estimation for repair and replacement (R&R) cost based on IFC data. First, we analyzed existing R&R criteria and defined BIM-based requirements when calculating R&R costs. These requirements were extracted from relevant IFC data. Subsequently, this was saved to a database and a BIM-based database was built for R&R cost estimation. Finally, this database was connected with external databases such as R&R Criteria DB and Cost Information DB to calculate R&R costs. This process is expected to improve upon the traditional process of cost estimation of R&R cost by applying a BIM model. The proposed process can contribute to a further standardizing of BIM-based LCC analysis thru application to initial construction costs, energy costs, and other maintenance costs.

• Fashion & Textile Research Journal
• /
• v.25 no.3
• /
• pp.324-332
• /
• 2023

Consumers are addressing the issue of dimensional dissatisfaction by repairing clothes, experimenting with style changes, and looking for cost-effective solutions that result in better-fitting garments. This study investigated the repair status by type of clothing, analyzed the method and frequency of repair by type of clothing category and season, and analyzed consumer redesign activities. The findings revealed that upper garments, such as T-shirts, jumpers, jackets, dress shirts, and dresses, were frequently repaired. The common modifications to upper garments included(in order of frequency) shortening sleeve length, shortening overall length, reducing garment width, zipper repair, and adjusting sleeve width. Lower garments, such as pants, jeans, skirts, and training pants, followed in terms of repair frequency. The modifications to lower garments included(in order of frequency) shortening length, reducing width, adjusting waist width (both narrowing and widening), replacing elastic bands, zipper repair, and lengthening. Repairs were more frequently conducted in the order of autumn, winter, spring, and summer. Repair methods varied depending on the clothing type and alterations involved to the length and width of garments and the replacement or removal of old sections. Redesigning clothing as a recycling method was found to enhance the cost-effectiveness of the collection. The study further confirmed the sustainability aspect of redesigning and reusing clothing.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.551-556
• /
• 2004

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The life-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.

• Proceedings of the Korean Reliability Society Conference
• /
• 2005.06a
• /
• pp.115-120
• /
• 2005

This paper introduces models for preventive maintenance policies and considers periodic preventive maintenance policy with minimal repair when the failure of system occurs. It is assumed that minimal repairs do not change the failure rate of the system. The failure rate under prevention maintenance received an effect by a previously prevention maintenance and the slope of failure rate increases the model where it considered. Also the start point of failure rate under prevention maintenance considers the degradation of system and that it increases quotient, it assumed. Per unit time it bought an expectation cost from under this prevention maintenance policy. We obtain the optimal period time and the number for the periodic preventive maintenance by using Nakagawa's Algorithm, which minimizes the expected cost rate per unit time. Finally, it suppose that the failure time of a system has a Weibull distribution as an example and we obtain an expected cost rate per unit time the optimal period time and the number when cost of replacement and cost of minimal repair change.