• Proceedings of the KSR Conference
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• 1998.11a
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• pp.71-78
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• 1998

Recently, continuous welded rail (CWR) track has been adopted for railway track structure of great advantages of reducing maintenance costs, and of increasing life time of track components and the comfort of passengers. But, in this case, a temperature or mechanical load will result in high stress and the track breakage or buckling may occur Especially when the CWR is laying on the bridge structure, the relative displacement of these structure can be increased and this results in the instability of track. In this paper, the main factors affect on the longitudinal rail force are discussed and the computer program is developed for the analysis of rail force considering the interactions with sub-structure.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.691-692
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• 2015

Several scholars in South Korea have predicted that maintenance costs of social infrastructure will sharply increase from the mid-2020s, and cause budgetary deficits among facilities management agencies. Interest in infrastructure asset management (IAM) is rising as a solution to such problem. In this study, an information system for asset valuation that reflects the salvage value and deferred cost of social infrastructure based on WBS (work breakdown structure) was developed in consideration of IAM. To reuse the construction cost information such as the acquisition cost, the interconnection between CBS (cost breakdown structure) and WBS was considered. Furthermore, asset valuation information was developed with XML schema to facilitate the exchange and reuse of the information among project participants.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1743-1753
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• 2011

Seoul Metropolitan Government has performed alternative transit system, light rail transit(LRT), for settling the problems of urban public transit system based on conventional bus service and heavy rail transit(HRT). LRT projects of total 8 lines(about 73.6km), including Ui-Sinseol line, have been planned as Build-Transfer-Operate(BTO) projects. For the first LRT, Ui-Sinseol line, however, design of structure had met standard for design of HRT, because of no domestic design code for LRT when participates of Ui-Sinseol project submitted the design proposal. This case study reports a successful example of LRT design minimizing the scale of stations designed in base of HRT code. The problems, like oversized structures compared with LRT vehicles, excessive costs for construction, had been resolved through negotiations with the participates of Ui-Sinseol line. Result suggests that present and future costs for construction and maintenance of the LRT projects in Seoul be considerably reduced in advance.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.47-57
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• 2016

As the inventory costs of repairable items in military logistics continue to increase, many studies for optimal inventory level of these items are being carried out in advanced countries, including the US, to reduce these costs. Research on inventory level optimization for repairable items aimed to achieve the availability goal of a system with a MIME(Multi Indenture Multi Echelon) repair policy structure first began with Sherbrooke's METRIC and developed into various types. This research is to analyze and compare recent V-METRIC related studies to search for another variation in this field. This paper mainly looks at how to determine optimum inventory level for each repairable item to achieve a specific availability target within a limited budget, and also how to minimize inventory cost while achieving its availability target by determining optimal inventory level of each repairable item.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.183-187
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• 2002

The efficient and rational transmission tariff structure is one of the crucial factors in creation of fair and competitive electricity markets. Transmission charge can be largely categorized into the line usage charge, system reliability charge, access charge and others. Any transmission tariff should be able to reflect these cost components reasonably. This paper suggests an approach amenable to allocating the transmission reliability costs reasonably with reflection of line sensitivity and line outage rate.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.269-275
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• 2002

Recently, Korea's electric industry has experienced substantial changes in its structure and function including the introduction of competition in the generation sector. Korea is in the early stages of market competition where the market price is determined by generation costs. In the future, the market Price will be determined by generators'bids. Therefore, the generators'profit is determined by market pool price, the prospects of pool price are very important for new capacity investment decision made by generators and IPPS. This study analyzes hourly marginal costs and LOLP considering basic generation mix and characteristics develops the relationship of pool price and Profit by generation-type using the change in reserve margin, and proposes basic direction for profits variation and supply-demand analysis in the electricity market in future.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.512-514
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• 2001

Recently, Korea's electric industry is in the midst of a period of profound changes in the structure and function, including the introduction of market competition in the generation sector. Korea is in the early stages of market competition, so the market price is chosen by generation costs but will be chosen by bids in future. Therefore, the profits of generators is determined by market pool price and the prospects of pool price are very important for new capacity investment determination of generators and IPPs. This study analyzes hourly marginal costs and LOLP considering basic generation mix and characteristics, develops the relationship of pool price using the above in competition market, and proposes basic direction for profits variation and supply-demand analysis in the electric market in future.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.4
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• pp.103-110
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• 2007

The facility location in designing a supply chain network is an important decision problem that gives form, structure, and shape to the entire supply chain system. Location problems involve determining the location, number, and size of the facilities to be used. The optimization of these location decisions requires careful attention to the inherent trade-offs among service time, inventory costs, facility cost, transportation costs. This paper presents a strategy that provides the best locations of distribution centers using GIS(Geographical Information System) assuming the limitation of delivery time. To get the best strategy of the location of distribution centers, we use the new loss functions as a penalty when the delivery time is violated

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.251-256
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• 2006

In this paper we consider multi-stage, multi-product production, inventory systems which have assembly-tree-structure. We propose a new mathematical model for pull type ordering systems based on JIT manufacturing systems. To apply the model to an actual automobile parts manufacturer, the objective of proposed model is to minimize the sum of inventory and setup costs. Finally, a numerical example and computational results are given to illustrate the proposed model.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.4
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• pp.174-179
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• 2022

Companies are making design changes by improving product quality and function to succeed while meeting customer requirements continuously. Design changes are changing the product BOM's amount, item, specification, and shape while causing a change in the product's structure. At this time, the problem of inventory exhaustion of parts before design change is a big topic. If the inventory exhaustion fails, the pieces before the design change become unused and are discarded, resulting in a decrease in asset value, and the quality cost of the design change affects the company's profits. Therefore, it is necessary to decide to minimize quality costs while minimizing waste inventory costs at the time of application of design changes. According to the analysis, priorities should be prioritized according to urgency because the quantity of items before the design change affects the applied lead time.