• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.9
• /
• pp.868-877
• /
• 2001

This study is to present the typical energy consumption criteria and $CO_2$ exhaust rate in multi-family housing complex by analyzing the energy consumption characteristics. The contents and methodology of this study are as follows; -Examining the documents of maintenance accounts, investigate the cost and its items expended by the annual maintenance in multi-family housing complex. -Survey each consumption of energy sources, maintenance area, location of multi-family housing complex, heating type, and so forth. -After classifying with heating type of multi-family housing complex investigated, Scrutinize the energy consumption by each source. -Analyze the characteristics of energy consumption and $CO_2$ exhaust through multiple regression analyses of maintenance property. -Suggest the typical energy consumption criteria (Mcal/$m^2$.year, Mcal/house.year) and $CO_2$ exhaust rate (kg-c/$m^2$.year, Kg-c/house.year) in multi-family housing complex. the results will come into basic data for estimating energy consumption in multi-family housing complex according to maintenance characteristics.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.765-770
• /
• 2005

This paper presents a development and evaluation of a spring type tensioning device for Korea railroad. The wheel type tensioning device used in the Korea railroad requires much time and labor for maintenance including wire replacement and oil application. So, we found it necessary to develop a new type of maintenance-free tensioning device. In this paper, we introduced a spring type tensioning device for Korea railroad.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.771-776
• /
• 2005

This paper presents field test results of a spring type tensioning device for Korea railroad. The wheel type tensioning device used in the Korea railroad requires much time and labor for maintenance including wire replacement and oil application. So, we found it necessary to develop a new type of maintenance-free tensioning device. In this paper, we introduced field test results of spring type tensioning devices for Korea railroad.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.277-278
• /
• 2023

The need for maintenance of bridge infrastructure is increasing due to aging, and the cost of maintaining the infrastructure must be calculated for effective budget distribution. Therefore, in this study, representative defects according to bridge superstructure type are derived to calculate the cost for each repair method. First of all, the representative bridges, PSCI girder bridge, Rahmen bridge, Steel box girder bridge, and RC slab bridge, were selected as superstructures using BMS data, and repair methods for defects were presented. In addition, the cost of the repair method by superstructure type was compared. This result is expected to predict total maintenance costs in consideration of the maintenance cycle.

• Journal of Information Technology Applications and Management
• /
• v.19 no.2
• /
• pp.181-196
• /
• 2012

The cost of software maintenance occupies about two thirds in the software lifecycle. However, it is not easy to estimate the cost of software maintenance because of various viewpoints about software maintenance, unclear estimation methods, and complex procedures. Until now, the cost estimation model has used compensation factors for software characteristic and environment on the basis of program size. Especially, most of existing models use maintenance rate of total software cost as a main variable. This paper suggests the software maintenance cost estimation model that uses the result of calculating real maintenance efforts. In this paper, we classify functional maintenance and non-functional maintenance as software maintenance activity type. For functional maintenance, present function point of target software is needed to evaluate. The suggested maintenance cost evaluation model is applied to a software case in public sector. This paper discusses some differences between our model and other modes.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.4
• /
• pp.187-198
• /
• 2022

This paper addresses the maintenance optimization problem in multi-component systems in which parts are connected in series, carrying out several missions interspersed with scheduled finite breaks. Due to limited time or resources, maintenance actions can be only carried out on a limited set of components. The decision maker then has to decide which components to maintain to ensure a pre-specified performance level during next mission. Most of the existing models in the literature usually assume only one system and enough spare parts. However, there are situations in which maintenance is required for multiple systems of the same type. To overcome this restrictive assumption, this study optimizes the maintenance problem considering the lack of repair parts and cannibalism for many identical systems. This study presents two optimization models with different objectives to solve the problem and analyzes the results so that the decision maker can decide. The results of this study are expected to be used for the maintenance of multiple systems of the same type, such as swarm drones.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1998.04a
• /
• pp.229-236
• /
• 1998

Port structures are one of the important infrastructure of the nation. To ensure safety and extend lifetime of the existing port structures, it is necessary to develop proper maintenance program. In this study, port inspection manual for pier type structure are developed. The flow of inspection program is designed and defect type for each component of wharf is classified. Also systematic method of rating and evaluation is developed together with conceptual design of port maintenance data base system.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.6 no.2
• /
• pp.7-11
• /
• 1981

An inspection-maintenance policy is investigated for a system having various states. A policy is characterized by the type of maintenance and the next inspection time. Maintenance actions are classified into various types according to the depth of maintenance. Policy evaluation criterion is the expected cost accumulated up to the failure of the system. The problem is formulated as a Markov decision process and an optimal policy is found by using a policy improvement procedure. A numerical example illustrates the policy for a system having five states.

• Industrial Engineering and Management Systems
• /
• v.7 no.2
• /
• pp.113-125
• /
• 2008

This paper presents a model for designing cellular manufacturing systems (CMS) by integrating system cost, machine reliability, and preventive maintenance (PM) planning. In a CMS, a part is processed using alternative process routes, each consisting of a sequence of visits to machines. Thus, a level of 'system reliability' is associated with the machines along the process route assigned to a part type. Assuming machine reliabilities to follow the Weibull distribution, the model assigns the machines to cells, and selects, for each part type, a process route which maximizes the overall system reliability and minimizes the total costs of manufacturing operations, machine underutilization, and inter-cell material handling. The model also incorporates a reliability based PM plan and an algorithm to implement the plan. The algorithm determines effective PM intervals for the CMS machines based on a group maintenance policy and thus minimizes the maintenance costs subject to acceptable machine reliability thresholds. The model is a large mixed integer linear program, and is solved using LINGO. The results point out that integrating PM in the CMS design improves the overall system reliability markedly, and reduces the total costs significantly.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.219-226
• /
• 2002

To systematic maintenance and record 10,000 port structures, under Ministry of Maritime and Fisheries, data base management system is required. In this study, POMIS(Port Maintenance and Information System) program is developed for this Purpose. In this program, records for inspection and repair for the various type of port structures can be maintained and operated through internet. Thus ministry can efficiently maintenance and repair port structures and systematically manage computerized maintenance and repair data.