• 전기의세계
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• v.24 no.5
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• pp.21-30
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• 1975

These studies aim to support technically the National Rural Electrification Program now in progress by analyzing several engineering problems in regard to the program and then suggesting some appropriate solutions or measures. The contents of these studies are divided into three categories; (1)optimized distribution systems for the rural electrification, (2)optimized rural illumination and (3)single-phase operation of three-phase motors.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.390-399
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• 2011

Generally the life-cycle cost of complex systems composed of several sub systems or equipments such as train, aircraft weapon systems is spent much more during operation and maintenance phase than development phase. The maintenance cost for maintaining the availability and extending the life span of systems comprise a large proportion of systems operation cost. The cycle of preventive maintenance affects operation and maintenance cost a lot. In this study we introduce a way minimizing life-cycle cost of systems by calculating more reliable preventive maintenance period than the results of previous study using systems reliability data considered the reliability and failure effect ratio of sub-systems or components. We can solve the preventive maintenance period problem known as NP-Hard as quick as possible by using modified genetic algorithm than using other models introduced in previous study.

• Journal of the Korean Institute of Navigation
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• v.23 no.4
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• pp.63-76
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• 1999

This paper aims at developing an integrated fleet management support system for industrial carriers who usually control the vessels of their own or on a time charter to minimize the cost of shipping their cargoes. The work is mainly concerned with the operational management problem of the fleet owned by a major oil company, a typical industrial carrier. The optimal fleet management problem for the major oil company can be divided into two phase problem. The front end corresponds to the production operation problem of the transportation of crude oil, the refinery operation, and the distribution of product oil to comply with the demand of the market. The back end is to tackle the fleet scheduling problem to meet the seaborne transportation demand derived from the front end. Relevant optimization models for each phase are proposed and described briefly. Then a user-friendly integrated fleet management support system is built based on the proposed optimization models for both ends under Windows environment. A case study reflecting the practices of fleet management problem for the major oil company is carried out by using the system.

• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.29-32
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• 1999

Korea Multi-Purpose SATellite(KOMPSAT) is scheduled to be launched by TAURUS launch vehicle in November, 1999. Tracking, Telemetry and Command(TT&C) operation and the flight dynamics support should be performed for the successful Launch and Early Orbit Phase(LEOP) operation. After the first contact of the KOMPSAT spacecraft, initial orbit determination using ground based tracking data should be performed for the acquisition of the orbit. Although the KOMPSAT is planned to be directly inserted into the Sun- synchronous orbit of 685 km altitude, the orbit maneuvers are required fur the correction of the launch vehicle dispersion. Flight dynamics support such as orbit determination and maneuver planning will be performed by using KOMPSAT Mission Analysis and Planning Subsystem(MAPS) in KOMPSAT Mission Control Element(MCE). The KOMPSAT MAPS have been jointly developed by Electronics and Telecommunications Research Institute(ETRI) and Hyundai Space & Aircraft Company(HYSA). The KOMPSAT MCE was installed in Korea Aerospace Research Institute(KARI) site for the KOMPSAT operation. In this paper, the orbit determination and maneuver planning are introduced and simulated for the KOMPSAT spacecraft in LEOP operation. Initial orbit determination using short arc tracking data and definitive orbit determination using multiple passes tracking data are performed. Orbit maneuvers for the altitude correction and inclination correction are planned for achieving the final mission orbit of the KOMPSAT.

• Journal of Applied Reliability
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• v.7 no.3
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• pp.101-110
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• 2007

The works of defence reliability have begun since the ILS team was organized in ROKA on March 2003. After that DAPA was opened at January 1st 2006 and those of defence reliability were reinforced. But the present of defence reliability is not enough. Many development and changes are required in the following area. The first is Master-plan making of defence reliability, and the second is making of the process of reliability. And then we have to enhance reliability of weapon system in the operation and support phase. The last is that policy is firmly executed among the defence organizations.

• Journal of Information Technology Applications and Management
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• v.12 no.4
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• pp.59-70
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• 2005

Flash memories are one of best media to support portable computer's storages in mobile computing environment. The features of non-volatility, low power consumption, and fast access time for read operations are sufficient grounds to support flash memory as major database storage components of portable computers. However, we need to improve traditional transaction management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. in order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient transaction processing. F2Pl improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process. We also propose a simulation model to show the performance of F2PL. Based on the results of the performance evaluation, we conclude that F2PL scheme outperforms the traditional scheme.

• The Bulletin of The Korean Astronomical Society
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• v.24 no.2
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• pp.83-83
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• 1999

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.271-274
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• 1996

Since the primary purpose of information Engineering focuses on transaction or operation processing, various information needs acquired in Information Strategy Planning phase are not properly utilized from the viewpoint of decision support systems development. In this research, we suggest a case-based reasoning application that supports initial Data Warehouse Modeling by expanding the activities in Information Strategy Planning.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.191-193
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• 2005

Flash memories are one of best media to support portable computer's storages. However, we need to improve traditional data management scheme due to the relatively slow characteristics of flash operation as compared to RAM memory. In order to achieve this goal, we devise a new scheme called Flash Two Phase Locking (F2PL) scheme for efficient data processing. F2PL improves transaction performance by allowing multi version reads and efficiently handling slow flash write/erase operation in lock management process.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.43-61
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• 2008

Performance based logistics(PBL) is recently studied and applied for enhancing the combat readiness and reducing the life-cycle cost for weapon system in the United States. Therefore, in this paper, we review the issues of logistic support and suggest alternatives to effectively manage the logistic support for weapon system by using performance based logistics, especially during operation and support phase of weapon systems.