• Journal of Korea Society of Industrial Information Systems
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• v.9 no.3
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• pp.32-37
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• 2004

This paper investigates the mathematical model of multi-server retrial queueing system with the Batch Markovian Arrival Process (BMAP), the Phase type (PH) service distribution and the finite buffer. The sufficient condition for the steady state distribution existence and the algorithm for calculating this distribution are presented. Finally, a formula to solve loss probability in the case of complete admission discipline is derived.

• Journal of Distribution Research
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• v.1 no.2
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• pp.199-220
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• 1996

Our courtry's distribrtion business is on the luring point by opening the market to foreign countries from this year. It can be said that industrial goods are intermediated goods for the production of other goods or service So it requires quality and specialty than any other things. But the lack of understanding, small scale and classification by non-productive industry by government bring about difficulty to the distribution itself and other fields. Industrial goods have a long distribution channel. This distribution stracture can be reduce the channel by establishment of distribution complex. Establishment of distribution complex will strengthen the role of quality management and go far toward quality improvement. This study examine the distribution status of industrial goods, problems and study the extablishment of complex and expected affect.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.2
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• pp.117-132
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• 2018

There always exist nonzero inspection errors whether inspectors are humans or automatic inspection machines. Inspection errors can be categorized by two types, type I error and type II error, and they can be regarded as either a constant or a random variable. Under the assumption that two types of random inspection errors are distributed with the "uniform" distribution on a half-open interval starting from zero, it was proved that inspectors overestimate any given fraction defective with the probability more than 50%, if and only if the given fraction defective is smaller than a critical value, which depends upon only the ratio of a type II error over a type I error. In addition, it was also proved that the probability of overestimation approaches one hundred percent as a given fraction defective approaches zero. If these critical phenomena hold true for any error distribution, then it might have great economic impact on commercial inspection plans due to the unfair overestimation and the recent trend of decreasing fraction defectives in industry. In this paper, we deal with the same overestimation problem, but assume a "symmetrical triangular" distribution expecting better results since our triangular distribution is closer to a normal distribution than the uniform distribution. It turns out that the overestimation phenomenon still holds true even for the triangular error distribution.

• IE interfaces
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• v.18 no.1
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• pp.63-72
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• 2005

In this paper, we present a distribution planning method for a supply chain. Like a typical distribution network of manufacturing firms, we have the form of arborescence. To consider more realistic situation, we investigated that an outside supplier has limited capacity. The customer demands are given in deterministic form in finite number of discrete time periods. In this environment, we attempt to minimize the total costs, which is the sum of inventory holding and backorder costs over the distribution network during the planning horizon. To make the best of the restricted capacity, we propose the look-ahead feature. For looking ahead, we convert this problem into a single machine scheduling problem and utilize tabu search approach to solve it. Numerous simulation tests have shown that the proposed algorithm performs quite well.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.3
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• pp.110-116
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• 2008

Operational strategy for inventory control in the distribution system has been given attention. If an individual enterprise implements the strategy, it is not easy to gain scale merits because of limited quantity or burden of inventory. In this study, we propose an operational strategy for inventory control that considers managerial integration of regional distribution centers (RDCs) and present a model of it. In a network of several RDCs, they could share inventory information and supply parts for others in case of an inventory shortage. And a numerical example of the network is illustrated, which compares two operational strategies, integration management of RDCs and individual management of them. The result shows total cost reduction in the strategy of integration management through the efficient inventory control of multi-echelon distribution.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.4
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• pp.256-262
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• 2016

The Weibull is widely used in reliability analysis, and several studies have attempted to improve estimation of the distribution's parameters. least squares estimation (LSE) or Maximum likelihood estimation (MLE) are often used to estimate distribution parameters. However, it has been proven that Bayesian methods are more suitable for small sample sizes than LSE and MLE. In this work, the Weibull parameter estimation accuracy of LSE, MLE, and Bayesian method are compared for sample sets with 3 to 30 data points. The Bayesian method was most accurate for sample sizes under 25, and the accuracy of the Bayesian method was similar to LSE and MLE as the sample size increased.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.201-207
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• 2007

As the power industry moves towards open competition, there has been a need for methodology to evaluate distribution power system reliability by using customer interruption costs, particularly in power supply zones under the competitive electricity market. This paper presents an algorithm to evaluate system average interruption duration index, expected energy not supplied, and system outage cost taking into consideration failure rate of the distribution facility and industrial customer interruption cost. Also, to apply this algorithm to evaluate system outage cost presented in this paper, the distribution arrangement of a dual supply system consisting of mostly high voltage customers in an industrial complex in Korea is used as a sample case study. Finally, evaluation results of system interruption cost, system average interruption duration index, and expected energy not supplied in the sample industrial complex area are shown in detail.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.77-82
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• 2004

Being in an internet era, the rapid transmission of 3D mesh models is getting more important and efforts toward the compression of various aspects of mesh models have been provided. Even though a mesh model usually consists of coordinates of vertices and properties such as colors and normals, topology plays the most important part in the compression of other information in the models. Despite the extensive studies on Edgebreaker, the most frequently used and rigorously evaluated topology compressor, the probability distribution of its five op-codes, C, R, E, S, and L, has never been rigorously analyzed yet. In this paper, we present probability distribution of the op-codes which is useful for both the optimization of the compression performance and a priori estimation of compressed file size.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.23-32
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• 2004

This paper addresses a model for the transportation planning that determines the transportation cycle time and the vehicle size to minimize the cost in a distribution system. The vehicle routing to minimize the transportation distance of the vehicles is also determined. A distribution system is consisted of a distribution center and many retailers. Products are transported from distribution center to retailers according to transportation planning. A model is assumed that the time horizon is continuous and infinite, and the demand of retailers is constant and deterministic. Cost factors are the transportation cost and the inventory cost, which the transportation cost is proportional to the transportation distance of vehicle when products are transported from distribution center to retailers, and the inventory cost is proportional to inventory amounts of retailers. A transportation cycle time and a vehicle size are selected among respective finite alternatives. The problem is analyzed, and a illustrative example is shown.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.33
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• pp.161-171
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• 1995

When physical distribution cost can be correctly measured, its management can also be efficient. Thus the primary objective of the study is to develop systems for measuring correctly physical distribution cost. The systems have two aspects : the One is the consumption of the resourses(materials, labor service, the other services), the other is the creation of physical distribution services(transportation, storage, cargo, packing, distribution conversion, management). By measuring the cost through the systems, the commoditization of the physical distribution services is possible and measurement of the cost and revenue can also be reasonable ,which makes its management efficient.