• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.93-113
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• 1997

In studying an EOQ-like inventory model for a manufacturing process, a number of findings were made. The system can "go out of control" resulting in a relatively minor problem state or "break-down". When the production system is in the minor problem statei produces a number of defective items. It is assumed that each defective piece requires rework cost and related operations. Once the machine breakdown takes place, the production system produces severely defective items that are completely unusable. Each completely unusuable item is immediately discarded and incurs handling cost, scrapped raw material cost and related operations. Two investment options in improving the production process are introduced : (1) reducing the probability of machine breakdown, breakdowns, and (2) simultaneously reducing the probability of machine breakdowns and setup costs. By assuming specific forms of investment cost function, the optimal investment policies are obtained explicitly. Finally, to better understand the model in this paper, the sensitivity of these solutions to changes in parameter values and numerical examples are provided.amples are provided.

• Journal of environmental and Sanitary engineering
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• v.15 no.2
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• pp.85-94
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• 2000

The comparative evaluation is the most effective method for site selection because the selection of waste treatment facility is to determine the optimum site out of limited candidate sites. This study adopted the ordinal scale evaluation, one of methods of comparative evaluation. The ordinal scale evaluation aims to determine the investigating items referring to the character of sites, to determine the importance factors for investigating items, and to determine the optimum site according to the quantitative evaluation. This study has focussed on reflecting the opinion of residents to the maximum extent with a weight on social and economic aspects, considering the state of confrontation against each other between the autonomous government organization and local residents, which is being emerged as a social issue relating to the evaluation rating on each item of site selection of an optimum site. Therefore, rational, and clear validity investigations and proper reduction of both time and expenses in site selection as well through this a study.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.97-110
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• 2000

Production schedule and realization quantity of Large type bus [929(HD), 928, 928-A(SD), 937E/L, 937/L,] were analyzed in order to intruoduce FMS(Flexible Manufacturing System) appropriate for varities of customer desire and multi-item, small lot production. And this paper is aimed to propose introduction method of FMS, analyzing zig tools change times and idle times with production line and workers as an object. According to analysis results, only simple spec., depending on bus type, changed with decrease in production. For 929(HD), 928,928-A(SD), 937Eh, 937/L bus type, there was no harmony between schdule and realization. Therefore, it caused many difficulties in part supply. And there was loss of manpower and reduction of productibility due to idle time of process with bus type change. Production processes were operated inefficiently because tact time exceeded or shortaged of allow time.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.09a
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• pp.183-192
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• 2001

1- Buildup PCB technology is utilized to a bare chip attach substrate technology for packaging of semiconductor chip 2- Requirement for the substrate design rule is described in SIA International Technology Roadmap for Semiconductor. 3- There are seven fabrication methods of build-up technology. 4- Coating and lamination for resin and photo, and laser for micro via hope processes are available. Below $50\mu\textrm{m}$ in diameter is possible. 5- Fine pitch lines down to $30\mu\textrm{m}$ can be achieved by pattern plating with better electrical property. 6- Dielectric loss reduction is a key material improvement item for next generation build-up technology. 7- High band width up to 512 GB/s is possible with current wiring groundrule.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.113-114
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• 2016

This paper proposes a technical requirements analysis of implementation of multi-trade prefabrication. Recently, there has been a rise in the use of prefabrication to minimize on-site work for time reduction to increase productivity. Prefabrication technique is evolved into multi-trade prefabrication combining other trades from single-trade prefabrication. For implementation of new technique, not only itself but complementary techniques have to be prepared. In this paper, MEP corridor rack, a major item of multi-trade prefabrication, was implemented in the test bed and its process was analyzed to find out technical requirements. As a result, comparatively high level of IT technique was required for efficient use of multi-trade prefabrication in design, lifting and construction phase. In design phase, component level of BIM library was needed for manufacturing; and in lifting phase, BIM-based site logistics process was required. Also in construction phase, laser scanning was implemented for gathering shape and geometry of the wall and slab that were attached to multi-trade prefabrication module.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2382-2386
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• 2008

Due to the reduction of greenhouse gases and a sharp increase in the energy prices the world over, there is a growing interest in the railroad transport. In particular, in the case of containers which are the major item of railroad transport, a need for the switchover from the road transport to the railroad transport is being suggested, however, it is understood that the extent of the switchover occurring is only marginal. There exist many causes that account for the marginal extent of the switchover to the railroad transport. Some of them have to be dealt with at the policy level and efforts are needed to make it more efficient to use the railroad than other means of transport by improving railroad logistics facilities. Thus, the present study seeks to examine the possible measures for improving the railroad logistics facilities to promote the railroad transport.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.123-128
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• 2012

This paper deals with the productivity increment through construction of HT8 production system for automobile factory in China. HT8 production system start to build up several management indices. The important management indices consists of organization management, location management, management of order, management of defective item, management of delivery information, and warehouse management. This HT8 production system is expected to obtain the improvement for overall organization management and reduction by 50% in warehouse cost.

• Korean Journal of Computational Design and Engineering
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• v.8 no.2
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• pp.101-108
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• 2003

Presented in this paper is the development of an product cost estimation system at the product design stage. The efficient cost estimation function at the design stage is essential for the cost reduction activities through the entire product life cycle. For this purpose, it is necessary to establish a systematic working procedure, and to develop information system for managing a great deal of production and product-related data required for the cost estimation. The developed system has the capability of estimating a cost of assembly type products as well as unit-item type products. As proposed system is based on the variant approach, it can be used easily at an early design stage without the need for detail design information. Also, this system is integrated with legacy PDM (Product Data Management) and ERP (Enterprise Resource Planning) system for fast. accurate and easy product cost estimation. The estimated cost includes material cost, overhead cost as well as labor cost.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.322-328
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• 2007

Highly standardized products are suitable for automated purchasing using electronic commerce technology, where the price becomes the most important factor. Suppliers can change the prices dynamically based on the inventory level and market situation in order to maximize the sales and profit. In the virtual marketplace where multiple customers purchase multiple standardized products from multiple suppliers repetitively, customers can purchase the required amount of each item as a dynamic bidding by allocating purchase orders to the suppliers based on the current price. Customers need a method to quickly determine the optimal allocation of orders to the suppliers using the dynamically changing data to minimize the total cost. We present a LP model which minimizes the sum of the total price plus transportation cost for this problem. Simulation results using random data show meaningful reduction of the total cost.

• International Journal of Reliability and Applications
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• v.5 no.2
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• pp.47-57
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• 2004

The market for used products is becoming more competitive and dealers of used products use warranty to promote sales as well as to provide assurance to customers. Offering warranty results in additional costs associated with warranty servicing. This cost can be reduced through actions such as overhaul and upgrade that improves the reliability of the item. This is worthwhile only if the cost of improvement is less than the reduction in the warranty servicing cost. This paper deals with two models to decide on the reliability improvement strategies for used items sold with FRW policy.