• Journal of Korean Society for Quality Management
• /
• v.15 no.1
• /
• pp.76-81
• /
• 1987

Past treatment of the single machine maintenance problem has shown that preventive maintenance may be desirable for equipment for which failures are caused at least partially by wear-out factors. In all previous treatment, however, the size of the maintenance-repair crew has been held constant and the optimal maintenance period has then been determined. This paper suggests a simultaneous solution for the maintenance-repair crew size and the optimal maintenance period. The optimal maintenance period is seen to shift as the size of the maintenance-repair crew varies.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.72-73
• /
• 2019

As the physical functions of school buildings and the changes in the functions of educational facilities due to social change are increasing, the demand for fundamental and long-term measures for the maintenance of educational facilities is expanding. However, depending on the function of the facility, the maintenance work has been carried out only when it is directly related to the safety problem, or when the request of the school facility manager is requested, rather than supporting preventive maintenance. In this study, we investigate the maintenance process of educational facilities and propose a method to manage the maintenance process of the educational facilities in the unit of space for establishing an efficient maintenance management system.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• 2006.11a
• /
• pp.692-697
• /
• 2006

The importance about the maintenance consideration of the building has a great impact and regarding the life continuation of the building the many interest is becoming intensively. The housing lot of the heart of urban at the capital region has insufficient recently and the construction of the ground complex building in solution for the insufficiency is increasing at the rapid pace. The ground complex building is brings the maximization of land use from inside the site, but maintenance consideration phase is caused by administration cost share and administration bound limit where person is concerned for a many problem point it contains. The objective of the present paper is that the building is maintain an efficiency initially and is improve in order to develop guide line for a maintenance consideration improvement from design phase. According as literature research and question research is enforce, the paper is escape problem point the maintenance consideration and is bring up guide line for the architectural plan field and the maintenance consideration improvement of the building. Result of the study is expected a help in maintenance consideration improvement during life cycle of the building

• Journal of Convergence for Information Technology
• /
• v.11 no.3
• /
• pp.125-131
• /
• 2021

The problem of determining the maintenance point which minimizes the process-related total cost is called the 'process mean shift problem'. By expanding and integrating the existing maintenance models that have been partially progressed, we present a expanded and integrated maintenance model which reflects the production site where various situations occur. To implement this, we set both the upper and lower limits of the product specification, and adopted the quality loss function for conforming items. Also, we set the process variance of the wear level as a function rather than a constant. In this study, we developed two general functions to the wear level. One is about the production volume and the other is maintenance cost. As a result, this study is expected to be a maintenance model that can be applied to various processes. In the future, this study can be developed as a profit maximization model by adding profit items from product sales, and expansion to a maintenance model that introduces failure to the model of this study can be considered.

• Journal of Korean Institute of Industrial Engineers
• /
• v.40 no.4
• /
• pp.428-434
• /
• 2014

Dry docks are used to repair warships or Merchant ships based on their life cycles. There are the certain number of dry docks in the ROK Navy, However, the ROK Navy force structure has been changing a lot since the Korean War. The focus of this study is to analyze the queueing problem regarding present dry docks capacities and to forecast the appropriate number of dry docks based on future naval ship structure. The study proposes to obtain an efficient dry dock size using queueing problem and simulation.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.784-791
• /
• 2007

Most operational organization and railway authority which conduct scheduled maintenance(SM) have carried out the preventive maintenance(PM) based on the information provided from supplier and manufacturer of railway system. However these activities are far away from reality and low the efficiency, it is because an appropriate methods for system selection didn't take into account for improving maintenance efficiency. Therefore, the current SM tasks and maintenance activities lead to lots of spend on the cost and time. To solve the above problem, this thesis presents new approach methodology. This proposes the criteria for reliability centered maintenance(RCM) system selection through level of quantification of each parameter, i.e, frequency, severity and maintenance cost, etc. To do this, the field operation data and information of maintenance cost are essential. As applying this methodology, we can look forward to improving efficiency of PM/SM, and reducing cost.

• IE interfaces
• /
• v.21 no.3
• /
• pp.254-261
• /
• 2008

Connected-(r,s)-out of-(m,n) : F system is an important topic in redundancy design of the complex system reliability and it's maintenance policy. Previous studies applied Monte Carlo simulation and genetic, simulated annealing algorithms to tackle the difficulty of maintenance policy problem. These algorithms suggested most suitable maintenance cycle to optimize maintenance pattern of connected-(r,s)-out of-(m,n) : F system. However, genetic algorithm is required long execution time relatively and simulated annealing has improved computational time but rather poor solutions. In this paper, we propose the ant colony optimization approach for connected-(r,s)-out of-(m,n) : F system that determines maintenance cycle and minimum unit cost. Computational results prove that ant colony optimization algorithm is superior to genetic algorithm, simulated annealing and tabu search in both execution time and quality of solution.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2020.11a
• /
• pp.57-58
• /
• 2020

Recently, government office buildings have become important in reducing maintenance costs. However, the loss of information raised a problem for maintenance work that could not meet the needs of users. Therefore, this study proposed a BIM-based integrated maintenance system for public offices in Jeju to efficiently maintenance work. The system can be integrated with IoT sensors, big data and artificial intelligence technologies to integrate information that occurs throughout the building's entire life cycle to exchange information. This system is also scalable to buildings, plants, region and urban infrastructure facilities as well as single buildings. It is expected that the system will provide reliable, high-quality, real-time information for efficient maintenance work, thereby supporting decision making and appropriate budget planning.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.44 no.1
• /
• pp.45-50
• /
• 2021

Machines and facilities are physically or chemically degenerated by continuous usage. The representative type of the degeneration is the wearing of tools, which results in the process mean shift. According to the increasing wear level, non-conforming products cost and quality loss cost are increasing simultaneously. Therefore, a preventive maintenance is necessary at some point. The problem of determining the maintenance period (or wear limit) which minimizes the total cost is called the 'process mean shift problem'. The total cost includes three items: maintenance cost (or adjustment cost), non-conforming cost due to the non-conforming products, and quality loss cost due to the difference between the process target value and the product characteristic value among the conforming products. In this study, we set the production volume as a decreasing function rather than a constant. Also we treat the process variance as a function to the increasing wear rather than a constant. To the quality loss function, we adopted the Cpm+, which is the left and right asymmetric process capability index based on the process target value. These can more reflect the production site. In this study, we presented a more extensive maintenance model compared to previous studies, by integrating the items mentioned above. The objective equation of this model is the total cost per unit wear. The determining variables are the wear limit and the initial process setting position that minimize the objective equation.

• Smart Structures and Systems
• /
• v.4 no.5
• /
• pp.641-653
• /
• 2008

This paper proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the lifetime performance and the life-cycle cost as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method using the life-cycle costs and the performance of bridges. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence and a corresponding algorithm has been implemented into the program. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.