• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.355-358
• /
• 2004

Currently, to overcome the limit of a 14V power supply system and to enhance the stability of this system high and to make the fuel efficiency better, a research development of a 42V power supply system is actively the progress. As an intermediate step to change into an unity power supply system, a 42V/14V dual power supply system uses a DC/DC Converter as one of structure elements. Considering the main electric power sources in the next generation of the car is a 42V system a 14V power supply system has advantages as follows : In be managed efficiently and to increase the redundancy at start, to jump start with any vehicles, etc. We need the introduction of a hi-directional converter that can flow the energy each other in a dual 42V-l2V system. This paper proposed the ZVS hi-directional CUK DC/DC converter which decrease the weight with the size of the DC/DC Converter and minimize the loss when the switching happen. In this paper, a circuit design method and an action principle of the circuit was proposed. To verify the proposed circuit, a comprehensive evaluation with theoretical analysis, simulation results is presented.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.53 no.4
• /
• pp.190-194
• /
• 2004

In this paper, UPS, which is embedded in computer power supply, is developed against the poor utility power system. In the developed system, PIC16C54 is used as the main controller, and UPS system consists of micom control module, power failure detecting module, charging module, power module, synchronous transfer module, and GUI module. Additionally, GUI module consists of battery charging state unit, power operating unit and operating state unit. The effectiveness of the developed system has been verified by the experimental results.

• Journal of Power System Engineering
• /
• v.11 no.3
• /
• pp.3-8
• /
• 2007

The emergency AC power supply system of the nuclear power plant is designed to supply the power to the nuclear reactor at the emergency operating condition. The safety function of the diesel generator at the nuclear power plant is to supply AC electric power to the plant safety system whenever the preferred AC power supply is unavailable. The reliable operation of onsite emergency diesel generator should be ensured by a conditioning monitoring system designed to maintain and monitor and forecast the reliability level of diesel generator. To do this kind of diesel generator condition monitoring we reviewed several operating factors and history of the wolsong unit 3 diesel generator and selected the proper conditioning monitoring operating factors.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.806-812
• /
• 2005

This paper proposes a new reliability evaluation for traction power system. The electric railway consists of traction power systems, various vehicles, operating equipment, track, overhead line and electric equipment. It is a fundamental function of traction power systems that supply customers with reasonable price, acceptable reliability and high quality power. In a general way, the power system reliability deals with the ability to satisfy load demands in supply capability or rating of every factor. On the other hand, the reliability of traction power systems has been focused on train time delay caused by power outage. In this paper, we make a selection optimum reliability indices for the reliability evaluation of electric traction power systems. The reliability study not only applies a plan for traction supply system after detecting the vulnerable point of existing traction supply systems but also makes a role in stable operating railway.

• Journal of Dairy Science and Biotechnology
• /
• v.19 no.1
• /
• pp.30-38
• /
• 2001

The most important task in Korean dairy industry is to keep the seasonal and annual balance of raw milk supply and demand. Too much surplus milk supply which causes dumping sale of market milk makes dairy industries get in trouble of management, and eventually affects to farmers and consumers economically. As balancing of supply and demand is so important in the fee economic market system, the adaption of the quota system of milk production and seasonal price differentiation has been recommended very often as a method of controlling the milk supply and demand. However, this recommendation did not go through successfully due to the strong objection of dairy farmers. Recently, the voice of consumer's requirement for safer and more hygienic, and high protein, low fat level dairy product is getting stronger. By knowledge of this kind changes, quality improvement in nutrients and hygiene is the most positive way to expand the volume of milk consumption. To meet the consumer's demand, therefore, it is necessary to revise the level of milk fat content and the hygienic grading system for the payment system of raw milk.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 2007.02a
• /
• pp.122-130
• /
• 2007

On the basis of analysis of the characteristic of production operations in tobacco enterprise, this paper explores the social environment and basic conditions of Tobacco Sales Enterprise, the system architecture and function module of the Supply Chain System of the Tobacco Sales Enterprise are described and it also discusses the application and management of supply chain system.

• The Journal of Society for e-Business Studies
• /
• v.7 no.2
• /
• pp.129-141
• /
• 2002

This paper deals with the collaborative procurement process in a two-echelon supply chain that a manufacturing company and a contractor are connected through the information system. The real time information about inventory and production processing becomes available through this information system. We raise two issues related to the collaborative procurement process. First, we propose a VMI(Vendor-Managed Inventory) type of the procurement policy which focuses on the cost minimization for the total supply chain rather than individual companies. Second, based on the simulation study, we demonstrate that a collaborative procurement process is more cost-effective over classical procurement processes such as (Q, r). The result obtained in this paper can be applied to the quantitative evaluation of the cost saving effect when companies build the information sharing based, collaborative procurement system.

• Korean System Dynamics Review
• /
• v.12 no.3
• /
• pp.67-86
• /
• 2011

This study shows the reduction effect of freight volume by the supply chain redesign for the alliance of distributors with system dynamics simulation. The as-is model is composed of 3 independent companies which one has 3 distribution centers (DCS) and 24 agents, another has 1 dc and 9 agents, the other has 3 DCS and 15 agents each. The to-be model is an integrated logistics model and composed of 1 company having 5 areal DCS and 38 agents. Each agent in the same area is integrated with each other. Two models have same demands but very different result. As a result, the freight volume between DCS and agents is reduced by 33.55%. This case study will be useful to analyze the similar cases about the logistics integration by supply chain redesign.

• The Journal of Information Systems
• /
• v.17 no.3
• /
• pp.135-152
• /
• 2008

Basically within a special regional area, a regional cluster seems to be based on core competencies of individual intra-cluster companies and collaboration among them. Information infrastructure has been emphasized as on one of competitive factors of a regional cluster, and it can be organized using collaboration system architecture integrated with each company's internal systems for efficient supply chain operation. As one of technical methods to prepare the system infrastructure supporting the collaboration of companies in a regional cluster, the Web Services can be effectively used. In this paper, a collaborative information system infrastructure for a regional cluster is suggested within the scope of supply chain management. And the efficiency of the proposed alternative is appraised with the features of a regional cluster.

• Journal of Power System Engineering
• /
• v.17 no.4
• /
• pp.31-35
• /
• 2013

The emergency AC power supply system of the nuclear power plant is designed to supply the power to the nuclear power plant at the emergency operating condition. The safety function of the diesel generator at the nuclear power plant is to supply AC electric power to the safety system whenever the preferred AC power supply is unavailable. The reliable operation of onsite standby diesel generator should be ensured by a condition monitoring system designed to maintain, monitor and forecast the reliability level of diesel generator. The purpose of this paper is to improve the existing ultrasonic sensor used for condition diagnosis of engine fuel pump and cylinder head for the accurate diagnosis in actual engine condition of emergency diesel generator(EDG). As a result of this study, we could design and develop much more reliable ultrasonic sensor than existing ones.