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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Operations Research and Management Science Society
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Journal DOI :
The Korean Operations and Management Science Society
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Volume & Issues
Volume 24, Issue 4 - Dec 1999
Volume 24, Issue 3 - Sep 1999
Volume 24, Issue 2 - Jun 1999
Volume 24, Issue 1 - Mar 1999
Volume 5, Issue 2 - 00 1999
Selecting the target year
An Optimal Algorithm for Repairable-Item Inventory System with Depot Spares
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 1~11
We consider the problem of determining the spare inventory level for a multiechelon repairable-item inventory system. Our model extends the previous results to the system which has an inventory at the central depot as well as bases. We develop an optimal algorithm to find spare inventory leveis, which minimize the total expected cost and simultaneously satisfy a specified minimum service rate. The algorithm is tested using problems of various sizes to verify the efficiency and accuracy.
A Study on Total Quality Evaluation Model of Information System Services
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 13~26
Recently, information technology and information system(IS) are rapidly diffused throughout the world. In the global competitive environment, the success of IS becomes the important one among the critical success factors(CSF) of the firm. For achieving it, the firm must continually involve itself in the quality evaluation and improvement of IS. The quality concept was changed into the customer-oriented quality one. There is no exception to the quality of IS. In the past, IS quality was determined by the IS developer or IS department offering service. Now it is evaluated by the user of IS service, and then the customer-oriented user satisfaction becomes an important issue. The purpose of this study is to develope the total quality evaluation model of IS through TQM approach. First, all success factors of the domestic IS are extracted from the foreign and domestic literatures of IS success factors contained the technical and behavioral aspects. And the extracted factors are classified with evaluation levels for quality evaluation and developed into a total quality evaluation model. Finally the model usefulness is analyzed.
Workload Smoothness in U-Shaped Production Lines Using Genetic Algorithms
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 27~37
In just-in-time production systems, U-shaped production lines rather than traditional straight lines are often adopted since they have some advantages. The advantages of U-lines over straight lines are that the workstations required can be reduced and the necessary number of workers can be easily adjusted when the demand rates are changed. In this paper, we present a new heuristic based on genetic algorithm to improve the workload smoothness in the U-line. In the proposed algorithm, a new genetic representation is developed which is specific to the problem being solved. To enhance the capability of searching good solutions, genetic operators are designed by using the problem-specific information and heuristics. Extensive experiments are carried out on well-known test-bed problems in the literature to verify the performance of our algorithm. The computational results show that our algorithm is a promising alternative to existing heuristics.
Improvement of AS/RS Class-based Storage Policy by Common Zone Allocation
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 39~47
It has been concluded that the performance of class-based storage policy is better than the performance of random storage policy in the literature. However, the rack shortage problem assigned to the 1st class items makes the decision hard to apply the class-based storage policy in practice. In this paper, a new common zone concept is introduced between two classes to resolve the problem with class-based storage policy. The common zone is the area to accept items from both classes. An AS/RS model is developed for computer simulation study and the effect of common area sizes with various AS/RS operation conditions is analyzed.
Structure Design of Artificial Neural Networks using Genetic Algorithm
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 49~62
Artificial Neural Networks(ANN) have been successfully applied to various kinds of business and engineering problems, especially those involved in pattern classification. However, because of the lack of design standard or guidelines, the structure of specific ANN depends on the designer's own experiments or choices. In other words, even though we could construct a better ANN, we often steeled down with just a satisfactory ANN. The purpose of this research is to apply the Genetic Algorithm(GA) to design a structure of ANN that yields better performance compared to the existing test results. For a bankruptcy prediction problem. an exiting research using ANN which consists of 22 input processing elements(PEs) for financial ratios and 5 hidden PEs showed 70% hit ratio. In our research, the input financial ratios and the number of hidden PEs are determined by GA. The best ANN, which consists of 8 input PEs and 6 hidden PEs, shows 78.03% hit ratio. In addition, we compare the performance of two types of reproduction schemes, i.e., generational reproduction and steady-state reproduction.
A Control of Channel Rate for Real-time VBR Video Transmission
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 63~72
Recent studies on the Constant Bit Rate and Variable Bit Rate transmissions have mainly focused on the frame by frame encoder rate control based on the quantization parameter. With the existing approaches it is difficult to guarantee a consistent video quality. Also, the rate control overhead is too high for the real-time video sources. In this paper, a channel rate allocation scheme based on the control period is proposed to transmit a real-time video, in which the control period is defined by a pre-specified number of frames or group of pictures. At each control period, video traffic information is collected to determine the channel rate at the next control period. The channel rate is allocated to satisfy various channel rate constraints such that the buffer occupancy at the decoder is maintained at a target level. If the allocated channel rate approaches the level at which the negotiated traffic descriptions may be violated, the encoder rate is decreased through adjusting quantization parameters in the MPEG encoder. In the experimental results, the video quality and the overflow and underflow probabilities at the buffer are compared at different control periods. Experiments show that the video quality and the utilization of network bandwidth resources can be optimized through the suitable selection of the control period.
A Genetic Algorithm for Single Machine Scheduling with Unequal Release Dates and Due Dates
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 73~82
In this paper, we address a single machine non-preemptive n-job scheduling problem to minimize the sum of earliness and tardiness with different release times and due dates. To solve the problem, we propose a genetic algorithm with new crossover and mutation operators to find the job sequencing. For the proposed genetic algorithm, the optimal pair of crossover and mutation rates is investigated. To illustrate the suitability of genetic algorithm, solutions of genetic algorithm are compared with solutions of exhaustive enumeration method in small size problems and tabu search method in large size problems. Computational results demonstrate that the proposed genetic algorithm provides the near-optimal job sequencing in the real world problem.
ATM Traffic Modeling with Markov Renewal Process and Performance Analysis
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 83~91
In order to build and manage an ATM network effectively under several types of control methods, it is necessary to estimate the performance of the equipments in various viewpoints, especially of ATM multiplexer. As for the method to model the input stream into the ATM multiplexer, many researches have been done to characterize it by, such as, fluid flow, MMPP(Markov Modulated Poisson Process), or MMDP (Markov Modulated Deterministic Process). We introduce an MRP(Markov Renewal Process) to model the input stream which has proper structure to represent the burst traffic with high correlation. In this paper, we build a model for aggregated heterogeneous ON-OFF sources of ATM traffic by MRP. We make discrete time MR/D/1/B queueing system, whose input process is the superposed MRP and present a performance analysis by finding CLP(Cell Loss Probability). A simulation is done to validate our algorithm.
Algorithm for the ATM Switching Node Location Problem
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 93~107
We consider the development of an integer programming model and algorithm for the ATM switching node location problem. There are two kinds of facilities, hub facilities and remote facilities, with different capacities and installation costs. Each customer needs to be connected to one or more hub facilities via remote facilities, where the hub(remote) facilities need to be installed at the same candidate installation site of hub(remote) facility. We are given a set of customers with each demand requirements, a set of candidate installation sites of facilities, and connection costs between facilities, We need to determine the locations to place facilities, the number of facilities for each selected location, the set of customers who are connected to each installed hub facilities via installed remote facilities with minimum costs, while satisfying demand requirements of each customer. We formulate this problem as a general integer programming problem and solve it to optimality. In this paper, we develop a branch-and-cut algorithm with path variables. In the algorithm, we consider the integer knapsack polytope and derive valid inequalities. Computational experiments show that the algorithm works well in the real world situation. The results of this research can be used to develop optimization algorithms to solve capacitated facility location problems.
On Fleet Sizing and Distribution Policy of Transportation Equipments in Pure Hub-and-Spoke Networks : The Case of Compound Poisson Process
Journal of the Korean Operations Research and Management Science Society, volume 24, issue 3, 1999, Pages 109~123
Fleet sizing and empty equipment redistribution are two of the most critical problems in managing a fleet of equipment over a transportation network. Where the demand pattern followed the compound Poisson process(CPP) which can be generated one or more at a time under homogeneous Poisson process(HPP), this paper presented a mathematical model to determine control parameters of a decentralized distribution policy and fleet size in case of the pure hub-and-spoke system, a popular form of a logistics system. and validated this model by simulation. That is, where the number of demanded equipments followed geometric and binomial distributions, respectively, cost models on the pure hub-and-spoke logistics system with deterministic trans-portation times, which could be solved analytically, were established and analyzed. We also compared the deterministic case with stochastic one that the transportation time follows some probability distributions