• Proceedings of the KSR Conference
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• 2008.11b
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• pp.2051-2057
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• 2008

This paper is a feasibility study on the calculation of operating cost in regards to the overall operation following the completion of a number of LRT lines currently in progress. Owing to the absence of operating experience in driveless LRT system at home, the difficulties lie in the assumption of the optimal operating budget applying domestic real situation. Nevertheless, with 34 years of accumulated operating experience in heavy rail transit system, Seoul Metro, the nation's biggest urban rail transit operator, performs O&M consultancy services for several on-going projects along with every effort to acquire know-how where the appropriateness of the cost estimation as a required deliverable is reviewed and a more efficient way is provided. The main focus of this study is to seek a method to calculate the optimal amount of operating expenses as well as a cost-effective alternative for possible weaknesses from the standpoint of the operator. The body of this paper discusses the five issues such as personnel cost, overhead, maintenance cost, additional purchase price, alternative investment fee from a more macroscopic point of view, and the conclusion deals with the adequacy of the reason for selection of institutions with various operating know-how.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.81-86
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• 2014

In this paper, a jointly optimal group replacement and spare provisioning policy is presented. Most maintenance policies assume that the spare inventory is always available, but in practice the maintenance schedule is affected by the availability of spare inventory. We present a maintenance-inventory model which jointly optimizes the group replacement interval and spare ordering quantity. Group replacement policy is used when a group of units are put in operation simultaneously. The operating fleet is replaced altogether at a predetermined number of units are failed. A sufficient level of spare inventory is carried to perform a number of group replacement. A cost rate expression which considers the group maintenance cost and inventory holding cost is derived and a heuristic method for searching the optimum value of decision variables is suggested. Numerical examples demonstrate the analytical results and the performance of the presented model.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.31-45
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• 2009

Reliability should be done from the initial stage of development to secure performance and safety of system. To establish and achieve target reliability of a system, reliability should be allocated into the subsystems. In the acquisition and development of a system, frequent failures will cause a negative effect on performing mission and occurs increasing operating cost. This study reviewed and evaluated the existing reliability allocation models using operation and maintenance costs to find the correlation between reliability allocation models and its operating cost. A target system reliability on the diesel engine to be developed for naval vessels is allocated into its subsystem based on the existing reliability allocation models. A selection methodology for reliability allocation models was made to minimize operating cost by using simulation based on the given operating diesel engine data for naval vessels.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.234-240
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• 1999

This paper presents a new approach for large-scale generator maintenance scheduling optimizations. The generator preventive maintenance scheduling problems are typical discrete dynamic n-dimensional vector optimization ones with several inequality constraints. The considered objective function to be minimized a subset of{{{{ { R}^{n } }}}} space is the variance (i.g., second-order momentum) of operating reserve margin to levelize risk or reliability during a year. By its nature of the objective function, the optimal solution can only be obtained by enumerating all combinatorial states of each variable, a task which leads to computational explosion in real-world maintenance scheduling problems. This paper proposes a new priority search mechanism based on each generator's discrete sensitivity value which was analytically developed in this study. Unlike the conventional capacity-based priority search, it can prevent the local optimal trap to some extents since it changes dynamically the search tree in each iteration. The proposed method have been applied to two test systems (i.g., one is a sample system with 10 generators and the other is a real-world lage scale power system with 280 generators), and the results anre compared with those of the conventional capacith-based search method and combinatorial optimization method to show the efficiency and effectiveness of the algorithm.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1144-1148
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• 2007

Seoul Metro is celebrating 32 anniversary this year and through developments over the years it is being evaluated as the 3rd in the world in operational sizes, the 4th in the world in facility sizes, it transports about 4 million passengers per day and it is now a vital public transportation means. However, the track maintenance organization and manpower structures along with technology cooperative office were led by unions that do not like changes and overshadows the trends of changes by expanding organizations and recruiting personnels and it is going against the current of times. Thus, it is time when a break point is required for breaking away from labor-intensive methods of the past that rely on hand works and vertical organizational structures. Therefore, this study investigates the states of national.international track maintenance operations and examines and analyzes the problems so that it can be utilized as base data for efficiently operating the organizations and maintenance works on track fields.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1382-1385
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• 2002

By managing various communication networks collectively, Telecommunication Management Network (TMN) has appeared as a concept to aim for the unified and effective communication network operation and maintenance. IMT-2000 and other network such as PSTN, cellular networks and packet witching network that are integrated with IMT-2000 have been developed in different platforms - hardware and operating system, and a same circumstance will happen in the maintenance in the future. Also, it is difficult to approach to the standard for Ｑ3 interface implementation of the agent in TMN system that may occur in the development or the maintenance for the different platform of IMT-2000 and other networks that are integrated with IMT-2000. In order to solve this kind of Problems, this Paper suggests integrated network management agent of IMT-2000 based on the NTS model and Advanced Intelligent Network(AIN).

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.259-264
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• 2003

Failure code system must include data of maintenance history, classification of failure, affective range and situation when failure occur. But the present failure code system have used a simple code system for classification to include only merchandise and tools. Advantageously, expansional standard code system that will be developed, it make that users can take steps of standardized overhaul and inspection as proposal maintain contents when failure occur or something wrong in vehicle of urban transit. Standardized failure codes must be developed and used that manufacturing companies and urban transit operating companies in order to give effect to maintenance works.

• Industrial Engineering and Management Systems
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• v.2 no.1
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• pp.63-70
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• 2003

In this study, we employed an arithmetic process (AP) approach to resolve gearbox maintenance problems. The approach is realistic and direct in modelling the characteristics of a deteriorating system such as a gearbox since a decreasing AP can model a gearbox's successive operating times and an increasing AP can model the corresponding consecutive repair times. First of all, two test statistics were used to check whether the process is arithmetic or not. Next, model parameters of the AP were estimated using the simple linear regression method. Finally, the optimal replacement policy based on minimising the long-run average cost per day was determined for each type of gearbox.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.91-99
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• 2013

PURPOSES : This study aims at proposing the methodology for benefit evaluations in pavement maintenance methods and timings using KoPMS(Korean Pavement Management System) software which was developed for efficient pavement management. METHODS : This study classified pavement sections into 4 clusters considering AADT(Annual Average Daily Traffic) and ESAL(Equivalent Single-Axle Load) using cluster analysis and used the deterioration models in each cluster. Increased user costs due to pavement deterioration as time goes by and agent costs for maintenance were estimated. Based on deterioration model and KoPMS software, Methodology for benefit evaluation was proposed in pavement maintenance methods and with/without implementation using real pavement section data. RESULTS : This study verified that considering agent costs only would be constrained to decide pavement maintenance methods and timings, and ascertained that decision making with agent and user costs would be effective. In addition, this study revealed that pavement maintenance methods and timings can be affected by AADT and ESAL and frequent pavement maintenances can be more efficient for benefits in pavement sections with more AADT and ESAL. Also this study found that user costs would be more affected to decision making than agent costs. Moreover, Delay of conducting pavement maintenance caused increased vehicle operating costs and environmental costs because of poor conditions of pavements. CONCLUSIONS : This study proposed LCCA and benefit estimation methodology of pavement with considering agent and user costs. The results of this study can be used for baseline data of efficient pavement asset management.

• KIEAE Journal
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• v.17 no.2
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• pp.35-43
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• 2017

Purpose: The purpose of this study is to find out the characteristics of service (landfill) costs (hereinafter, the "landfill costs") applied to the dissolution promotion committee and analyze the characteristics of landfill costs at the time where the dissolution of promotion body is increasing with the authority of the head of local government regarding the territory difficult with the continuous promotion by delaying or suspending the project for a prolonged period or suspending the project through the dissolution of the project body by the promotion committee and cooperative union since the flawless promotion of the maintenance project. Method: After revising the law in February 2012, the survey and analysis is made for the status of applying landfill costs and maintenance project scale of the dissolution promotion committee not confirmed in details around a total of 20 regions, including, 9 regions of redevelopment projects completed with the advance review, 7 regions of re-construction projects and 4 regions of urban environment maintenance projects from the total of 59 regions, Result: The influence on the landfill costs is shown to be greatest in the service expenses and management and supervision on this field has significance for the maintenance project perceived as private project, rather than public project, that the public management is neglected with insufficient presentation of operation criteria and so forth that it displays the tendency to lead to the discrete operation of the project body. In order to enhance the transparency of operating costs for the projects that are led by private capital, it is required to strengthen the role of public sector through enthusiastic intervention by the public sector in standardization of operation criteria, presentation of guideline and so forth.