• IE interfaces
• /
• v.16 no.4
• /
• pp.441-449
• /
• 2003

In this paper we propose a distribution planning method aiming the use in the real-life situations. The assumed form of the distribution network is arborescence. At every node in the distribution network, orders are placed periodically. At each renewal of planning horizon, demand informations of periods in the horizon are updated. The objective of the problem is to minimize the total cost, which is the sum of holding and backorder costs of all sites during planning horizon. For such a situation, this study addressed an effective distribution plan when demands for demand-sites are provided for a given planning horizon.

• Journal of Korean Institute of Industrial Engineers
• /
• v.28 no.4
• /
• pp.443-453
• /
• 2002

Many firms are trying to optimize their production and distribution systems separately, but possible profit increase by this approach is limited. Nowadays, it is more important to analyze these two systems simultaneously for the integrated supply chain management. This paper is a computational study to investigate the effectiveness of integrating production and distribution scheduling. We are interested in a multi-plant, multi-retailer, multi-product and multi-period industrial problem where the objective in solving production and distribution scheduling problem is to maximize the total net profit. Computational results on test problems of various sizes using the heuristic we developed show a substantial advantage of the integrated scheduling approach over the decoupled scheduling process. Sensitivity analysis on the parameter values indicates that, under the right conditions, the effectiveness of integrating production and distribution functions can be extremely high.

• Journal of the Korean Data and Information Science Society
• /
• v.17 no.3
• /
• pp.687-705
• /
• 2006

In this paper we consider GPH distribution that is defined as a distribution for sum of random number of random variables following exponential distribution. We establish approximation process of general distributions to GPH distributions and offer numerical results for various cases to show the accuracy of the approximation. We also propose analysis method of delay distribution of queueing systems using approximation to GPH distributions and offer numerical results for various queueing systems to show applicability of GPH approximation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.9
• /
• pp.2253-2260
• /
• 2009

The typical distribution systems have the power flow from distribution substations (sources) to customers (load) only as one direction. However, in the case where new energy power sources are connected to distribution systems, the output variations of new energy sources to distribution systems, which is so called reverse power flow, may cause the bi-directional power flow. So, the reverse power flow has severe impacts on typical power system, for example power quality problems, protection coordination problems, and so on. Therefore, this paper proposes the algorithm for Multi-functional protection devices in distribution systems in the case where new energy sources are interconnected. The proposed algorithm is verified to show the effectiveness by simulating and experimenting the prototype systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 1987.10b
• /
• pp.619-624
• /
• 1987

A study on distribution automation system suitable to distribution system of KEPCO has started since 1984, and the field trial system for ADS will be operated for testing. This paper will describe project and planning for field trial of KEPCO.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.11
• /
• pp.3130-3136
• /
• 2009

This paper deals with the optimal on-line real time voltage regulation methods in power distribution systems interconnected with the Distributed Generation(DG) systems. In order to deliver suitable voltage to as many customers as possible, the optimal sending voltage should be decided by the effective voltage regulation method by using artificial neural networks to consider the rapid load variation and random operation characteristics of DG systems. The results from a case study show that the proposed method can be a practical tool for the voltage regulation in distribution systems including many DG systems.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.864-868
• /
• 2008

Water transmission and distribution systems play a important role to deliver safe and clean water and are responsible for the most direct impacts of water utilities to customers. Although the performance of WDS(Water Distribution Systems) should be evaluated by a certain standards, interests has not been in WDS and developed due to invisible, hard-working and insufficient information in the evaluation process in Korea till now. The investigations and researches were carried out to develop software to assist the evaluation of WDS with respects to hydraulics, water quality and structural analysis methods. The methodologies have been developed which can be used to estimate the performance to water distribution network and software are implemented by the process. Developed systems are consisted with database, analysis techniques, simulation models, decision support systems and other tools. The concepts and functions are introduced in this paper and the performance index are discussed for accurate assessment of water distribution systems.

• Applied Science and Convergence Technology
• /
• v.23 no.6
• /
• pp.357-365
• /
• 2014

A non-invasive method for ion energy distribution measurement at a RF biased surface is proposed for monitoring the property of ion bombardments in capacitively coupled plasma sources. To obtain the ion energy distribution, the measured electrode voltage is analyzed based on the circuit model which is developed with the linearized sheath capacitance on the assumption that the RF driven sheath behaves like a simple diode for a bias power whose frequency is much lower than the ion plasma frequency. The method is verified by comparing the ion energy distribution function obtained from the proposed model with the experimental result taken from the ion energy analyzer in a dual cathode capacitively coupled plasma source driven by a 100 MHz source power and a 400 kHz bias power.

• Korean Journal of Hydrosciences
• /
• v.8
• /
• pp.31-40
• /
• 1997

Flow carrying capacity of water distribution systems is getting reduced by deterioration of pipes in the systems. The objective of this paper is to present a managerial decision-making model for the rehabilitation of water distribution systems with a mininum cost. The decisions made by the model also satisfy the requirements for discharge and pressure at demanding nodes in the systems. Replacement cost, pipe break repair cost, and pumping cost are considered in the economic evaluation of the decision along with the break rate and the interest rate to determine the optimal replacement time for each pipe. Then, the hydraulic integrity of the water distribution system is checked for the decision by a pipe network simulator, KYPIPE, if discharge and pressure requirements are satisfied. In case the system does not satisfy the hydraulic requirements, the decision made for the optimal replacement time is revised until the requirments are satisfied. The model is well applied to an existing water distribution system, the Seoul Metropolitan Water Supply System (1st Phase). The results show that the decisions for the replacement time determined by the economic analysis are accepted as optimal and hydraulic integrity of the system is in good condition.

• 전기의세계
• /
• v.18 no.6
• /
• pp.23-32
• /
• 1969

The thesis has derived the formulas and computational algorithms useful for predicting and constraining the potential rises on the neutral line in 3-phase, 4-wire distribution line systems in the case of contact faults and single-line grounding faults. In addition it has suggested economically optimal designing conditions herewith of the distribution line systems in conduction with the potential restraining cost functions.