• 대한안전경영과학회지
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• 제8권3호
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• pp.103-114
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• 2006

A cross docking operation involves multiple trucks (known as inbound trucks) that deliver items from suppliers to a distribution center and multiple trucks (known as outbound trucks) that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. A unique characteristic of a cross docking system is the absence or prohibition of long term storage of items at the distribution center. Items delivered to the distribution center from suppliers are shipped to customers as soon as possible without being placed in storage in the distribution center. The objective of this paper is to develop the optimal operational strategy for finding the best truck docking sequence for both inbound and outbound trucks in order to minimize total operation time where a temporary storage area is not available in a cross docking system.

• 전기학회논문지
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• 제58권10호
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• pp.1869-1880
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• 2009

Distribution line fault has been reduced gradually by the efforts on improving the quality of electrical materials and distribution system maintenance. However faults caused by medium voltage customers have been increased gradually even though we have done many efforts. The problem is that we don't know which customer will cause the fault. This paper presents the concept to find these customers using data mining techniques, which is based on accumulated fault records of medium voltage customers in the past. It also suggests the prediction model construction of medium voltage customers causing distribution line fault and methods to enhance the reliability of distribution system. We expect that we can effectively reduce faults resulted from medium voltage customers, which is 30% of total faults.

• 산업공학
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• 제12권2호
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• pp.222-236
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• 1999

This paper presents a design and implementation of an intelligent-integrated production-logistics systems. The situation considered here is that there are multiple manufacturing plants and multiple distribution centers. Effective distribution resource and production planning are required to reduce inventory cost and to avoid inventory shortage. We propose an intelligent forecasting scheme of each distribution centers, adaptive inventory replenishment planning, distribution resource planning, and integrated production planning system. In forecasting a huge number of on-line model identification is performed using neural network approximation capability. An efficient adaptive replenishment planning and distribution resource planning are also presented in connection with forecasting scheme. An appropriate production is also requested based on production lead-time and the results of distribution planning. Experimental simulations are presented to verify the proposed approach using real data.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1438-1440
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• 2005

A power control and distribution unit(PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU scheme for the small LEO Satellite applications. The main constitutes of the PCDU are the battery interface module, the auxiliary supply modules, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation. and instrument power distribution modules.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.822-828
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• 2001

Three-phase four-wire electrical distribution systems are widely employed in manufacturing plants, commercial and residential buildings. Due to the nonlinear loads connected to the distribution system, the neutral conductor carries excessive harmonic currents even under balanced loading since the triplen harmonics in phase currents do not cancel each other. This may result in wiring failure of the neutral conductor and overloading of the distribution transformer. In response to these concerns, a cost-effective neutral current harmonic suppressor system has been proposed [6]. This paper proposes an improved control method for the harmonic suppressor system under unbalanced load conditions. The proposed control method compensates for only the harmonic components in the neutral conductor, and the zero-sequence fundamental component due to unbalanced loading is prevented from flowing through the harmonic suppressor system. This remedies overloading and power loss of the system. The experimental results on a prototype validate the proposed control approach.

• 한국분무공학회지
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• 제1권1호
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• pp.85-91
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• 1996

This experiment was undertaken to investigate spray characteristics of the conventional inject ion system and the ultrasonic energy added inject ion system. Sauter mean diameter was mesured under the variation of inject ion pressure and the spray distance. To measure the droplet size we used the Malvern system 2600C. The spray angle and mass distribution was analyzed to the CCD camera and the patternater. After experiment, it was found that the ultrasonic energy added injection system had smaller sauter men diameter of droplet, wider mass distribution and wider spray angle than the conventional inject ion system had.

• 설비공학논문집
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• 제16권6호
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• pp.556-565
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• 2004

We have experimented an actual solar water heating system acquiring real data for one year period. On the basis of the operation data, it is necessary to predict the system performance such as collector efficiency and solar fraction, and to analyze the economical efficiency for system optimal design. To estimate the performance of actual systems through simulation, valid modelling for components consisting of the system should be accompanied. The present study is focused on the modelling for load patterns and operating control conditions. We proposed two load models: concentration model which gathers real loads as a meaningful group and distribution model which disperses real loads with time. If grouping of the load distribution is suitable, the predicted values by the concentration model approaches to those by the distribution model close to actual load pattern apparently. As a result, both of them are in good agreement with those by experiment.

• 에너지공학
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• 제8권1호
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• pp.76-84
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• 1999

The demand of Small Self-generating System (SSS) including Small Cogeneration System (SCS) is constantly increasing with the need of electricity and/or thermal in office, hospital, hotel, and small factory, etc. It is especially recommended to operate SCS in the heat-following mode to maximize the efficiency of generator. In case of the heat-following mode SCS has got to be connected to distribution system so as to send surplus power to the utility or receive the short power from utility. But the interconnection of SSS with distribution system causes a few problems such as the bad power quality, and low security. If SSS is not promptly disconnected after faults occur (Islanding of SSS), it can not only damage equipment of utility and adjacent customers but also endanger life of human due to overvoltage or overcurrent. In this paper it has been deeply discussed if interconnection of engine self-generator/control system satisfies the protective requirement for SSS or not. 500 kW engine generator running in the Jodo island has been used to perform the analysis of interconnection.

• 대한전기학회논문지:전력기술부문A
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• 제49권1호
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• pp.1-5
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• 2000

This paper presents a new algorithm to restore the de-energized loads in electric power distribution systems for restoration by utilizing object-based structure and heuristic rules without branch and feeder overloading. In order to cope with a complex network configuration and frequent breaker switching operations in distribution systems, the component of power system is described as objects and the information of system configuration is constructed by connecting objects each other. Such a strategy is developed mainly based on the object search algorithm to increase computation efficiency. As a result, the proposed system has been implemented to efficiently deal with large distribution systems by reducing computational burden remarkably compared with the conventional methods.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.550-551
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• 2000

This paper suggests the system which monitors and diagnoses the distribution transformers. Moreover, this paper has established the system for the multi diagnoses by all the informations. Through the proven oil sensor, the oil temperature, capacitance and $tan{\delta}$ could be measured throughly, and followed by these informations, detected problems of the distribution transformers, using wireless data communication, could directly reported to the main host. For this, the proposed system is divided into sensor part and controller part. To prove the usefulness of the system, the paper compared and analyzed the system with the existing one, and after studying the correlation of the both, the result proved its goodness.