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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 23, Issue 4 - Dec 1998
Volume 23, Issue 3 - Sep 1998
Volume 23, Issue 2 - Jun 1998
Volume 23, Issue 1 - Mar 1998
Selecting the target year
Facets of Knapsack Polytopes with Bipartite Precedence Constraints
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 1~10
We consider the precedence-constrained knapsack problem. which is a knapsack problem with precedence constraints imposed on the set of variables. Especially, we focus on the case where the precedence constraints cir be represented as a bipartite graph, which occurs most frequently in applications. Based on the previous studios for the general case, we specialize the polyhedral results on the related polytope and derive stronger results on the facet-defining properties of the inequalities.
A Method for finding the k Most Vital Arcs in the Shortest Path Problem
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 11~20
This paper deals with a mathematical model and an algorithm for the problem of determining k most vital arcs in the shortest path problem. First, we propose a 0-1 integer programming model for finding k most vital arcs in shortest path problem given the ordered set of paths with cardinality q. Next, we also propose an algorithm for finding k most vital arcs ln the shortest path problem which uses the 0-1 Integer programming model and shortest path algorithm and maximum flow algorithms repeatedly Malik et al. proposed a non-polynomial algorithm to solve the problem, but their algorithm was contradicted by Bar-Noy et al. with a counter example to the algorithm in 1995. But using our algorithm. the exact solution can be found differently from the algorithm of Malik et al.
An Efficient Minimum Degree Ordering Method Using the Lower Bounds of Degrees
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 21~31
Ordering is used to reduce the amount of fill-ins in the Cholesky factor of an symmetric definite matrix. One of most efficient ordering methods is the minimum degree ordering method. In this paper. we propose the two techniques to improve the performance of the minimum degree ordering which are implemented using clique storage structure. One is node absorption which is a generalized version of clique absorption. The other technique is using the lower bounds of degree to suspend the degree updates of nodes. finally, we provide computational results on the problems on NETLIB. These results show that the proposed techniques reduce the number of degree updates and the computational time considerably
Operational Optimization Analysis of Industrial Operators' Fleet
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 33~51
The industrial operation is one of the three basic modes of shipping operation with liner and Tramp operations. Industrial operators usually control vessels of their own or on a time charter to minimize the cost of shipping their cargoes. Such operations abound in shipping of bulk commodities, such as oil, chemicals and ores. This work is concerned with an operational optimization analysis of the fleet owned by a major oil company. a typical industrial operator. The operational optimization problem of the fleet of a major oil company is divided Into two phase problem. The front end corresponds to the optimization problem of the transportation of crude oil. product mix. and the distribution of product oil to comply with the demand of the market. The back end tackles the scheduling optimization problem of the fleet to meet the seaborne transportation demand derived from the front end. A case study reflecting the practices of an international major oil company is demonstrated to make clear the underlying ideas.
Analysis of Optimal Kanban Cycle Time
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 53~61
In this paper, we take into consideration the optimal cycle time in a kanban system. Even though there are many studios in the literature published in the past. It is rare to fine a paper dealing with kanban cycle time. We consider manufacturing structure configured in the real field and suggest kanban cycle time for the cases of linear, tree assembled, distributed, general and mixed structures. Also we give numerical example for each structure.
A Study on Even Distribution of Workloads Using Simulated Annealing Method on Integrated Layout Design in Cellular flexible Assembly Systems
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 63~73
With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.
Saving Tool Cost in Flexible Manufacturing Systems: Joint Optimization of Processing Times and Pallet Allocation
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 75~86
We address the problem of determining the optimal processing times and pallet/fixture allocation in Flexible Manufacturing systems in order to minimize tool cost while meeting throughput targets of multiple part types. The problem is formulated as a nonlinear program superimposed on a closed queueing network of the FMSs under consideration. A numerical example reveals the potential of our approach for significant cost saving. We argue that our model can be Integrated Into the process planning system of an FMS to generate efficient process plans quickly.
A Method of Eliminating Exceptional Elements Attaining Minimum Machine Duplications and Intercell Moves In Cellular Manufacturing Systems
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 87~96
Using the concept of cellular manufacturing systems(CMS) in job shop manufacturing system is one of the most innovative approaches to improving plant productivity. However. several constraints in machine duplication cost, machining capability, cell space capacity, intercell moves and exceptional elements(EEs) are main problems that prevent achieving the goal of maintaining an ideal CMS environment. Minimizing intercell part traffics and EEs are the main objective of the cell formation problem because it is a critical point that improving production efficiency. Because the intercell moves could be changed according to the sequence of operation, it should be considered in assigning parts and machines to machine ceil. This paper presents a method that eliminates EEs under the constraints of machine duplication cost and ceil space capacity attaining two goals of minimizing machine duplications and minimizing intercell moves simultaneously. Developing an algorithm that calculates the machine duplications by cell-machine incidence matrix and part-machine Incidence matrix, and calculates the exact intercell moves considering the sequence of operation. Based on the number of machine duplications and exact intercell moves, the goal programming model which satisfying minimum machine duplications and minimum intercell moves is developed. A linear programming model is suggested that could calculates more effectively without damaging optimal solution. A numerical example is provided to illustrate these methods.
An Approximate Analysis of a Stochastic Fluid Flow Model Applied to an ATM Multiplexer
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 97~109
In this paper, we propose a new approach to solve stochastic fluid flow models applied to the analysis of ceil loss of an ATM multiplexer. Existing stochastic fluid flow models have been analyzed by using linear differential equations. In case of large state space, however. analyzing stochastic fluid flow model without numerical errors is not easy. To avoid this numerical errors and to analyze stochastic fluid flow model with large state space. we develope a new computational algorithm. Instead of solving differential equations directly, this approach uses iterative and numerical method without calculating eigenvalues. eigenvectors and boundary coefficients. As a result, approximate solutions and upper and lower bounds are obtained. This approach can be applied to stochastic fluid flow model having general Markov chain structure as well as to the superposition of heterogeneous ON-OFF sources it can be extended to Markov process having non-exponential sojourn times.
Estimating System Reliability under Brown-Proschan Imperfect Repair with Covariates
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 111~130
We propose an imperfect repair model which depends on external effects quantified by covariates. The model is based on the Brown-Proschan imperfect repair model wherefrom the probability of perfect repair is represented by a function of covariates. We are motivated by deficiency of the BP model whose stationarity prevents us from predicting dynamically the time to next failure according to external condition. Five types of function for the probability of perfect repair are proposed. This article also presents a procedure for estimating the parameter of the function for the probability of perfect repair, as well as the inherent lifetime distribution of the system, based on consecutive inter-failure times and the covariates. The estimation procedure is based on the expectation-maximization principle which is suitable to incomplete data problems. focusing on the maximization step, we derive some theorems which guarantee the existence of the solution. A Monte Carlo study is also performed to illustrate the prediction power of the model as well as to show reasonable properties of the estimates. The model reduces significantly the mean square error of the in-sample prediction. so it can be utilized in real fields for evaluating and maintaining repairable systems.
A Study on the Aggregation of Multi-Experts Priorities Using Compatibility in the AHP
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 131~140
The objective of this study is to propose a new procedure to synthesize the multi-experts priorities in AHP. If multi-experts with different expertise are involved in a AHP decision, we need some way to aggregate their opinions. AHP model used to do numerical aggregation by taking only the geometric mean or the weighting geometric mean in past. To aggregate the multi-experts priorities, In this paper. we suggest a way which Decision Maker can exclude outlier matrix from group using the concept of the Compatibility and we Introduce Delphi method to use Compatibility in AHP. A numerical example is shown to illustrate the procedure.
Sensitivity Analysis of Decision Tree's Learning Effectiveness in Boolean Query Reformulation
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 141~149
One of the difficulties in using the current Boolean-based information retrieval systems is that it is hard for a user, especially a novice, to formulate an effective Boolean query. One solution to this problem is to let the system formulate a query for a user from his relevance feedback documents in this research, an intelligent query reformulation mechanism based on ID3 is proposed and the sensitivity of its retrieval effectiveness, i.e., recall, precision, and E-measure, to various input settings is analyzed. The parameters in the input settings is the number of relevant documents. Experiments conducted on the test set of Medlars revealed that the effectiveness of the proposed system is in fact sensitive to the number of the initial relevant documents. The case with two or more initial relevant documents outperformed the case with one initial relevant document with statistical significances. It is our conclusion that formulation of an effective query in the proposed system requires at least two relevant documents in its initial input set.
Atmospheric Clearness Estimation of Major Cities in Korea Using Empirical forecasting Models
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 151~169
Since the atmospheric clearness index is one of the main factors for evaluating atmospheric circumstances, it is necessary to estimate its characteristics all over the cities in Korea. This study was focused on the evaluation of atmospheric condition for each 15 cities in terms of respectively or mutually analyzed clearness factor that was predicted on the assumed clear day with the model using factors such as average global insolation. cloud amount, and duration of sunshine measured for two years between 1996 and 1997. The new clearness index data will be extensively used by atmospheric circumstances analysts as well as by solar application designers or users.
The Impact of Croup Member Characteristics on the Use of GDSS
Park, Moo-Jin ;
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 171~186
While one main stream of research in GDSS (Group Decision Support System) is to investigate how GDSS affects decision-making performances of groups according to task types, support features, meeting facilitation modes and meeting environments. little study h3s been done about how group characteristics affect group decision processes and outcomes depending upon GDSS is provided or not. So far, most GDSS research has considered group characteristics (e.g. personality homogeneity) as given and did not include it as control variables in experiments. Therefore, the objective of this study is to investigate how members of two different groups perceive the use of GDSS in group meetings through lab experiments. The two groups are homogeneous and heterogeneous groups in terms of members' personality mix. This research found that the effect of GDSS is a function of groups' personality homogeneity in regards of the satisfaction on decision process and the communication thoroughness. The support of GDSS and the group homogeneity are proved to influence participant's perception about some dependent variables such as satisfaction on decision process.
A Coevolutionary Algorithm for Working and Backup Virtual Path Routing
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 187~201
In ATM networks with high capacity, the effect of failures on transmission links or nodes can be catastrophic, so that the issue of survivability is of great importance. In this paper. we consider the routing problem for working and backup virtual paths(VPs). To accomplish a higher survivability. routing the two kinds of VPs should be taken into account at the same time because backup VP routing depends on the working VP routing. A coevolutionary algorithm is employed to solve the problem for simultaneously routing of working and backup VPs. To develop an efficient coevolutionary algorithm for the problem. structure of populations, encoding method, neighborhood, and genetic operators are studied in this paper. The results of extensive experiments are reported. The performance comparison of the proposed algorithm with a conventional genetic algorithm and existing heuristics shows that our approach is promising.
A Study on the Inference Mechanism Using a Levelized FCM
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 203~212
A Study on the Investment Strategy Using Neural Network Models in the Korean Stock Market
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 213~224
Since the late 1980s, an Increasing number of neural network models have been studied in the areas of financial prediction and analysis. The purpose of this study is to Investigate the possibility of building a neural network model that is able to construct a profitable trading strategy in the Korean Stock Market. This study classifies stocks into the future market winners and losers from the publicly available accounting information and builds portfolios based on this information. The performances of the winner portfolios and the loser portfolios are compared with each other and against the market index. The empirical result of this research is consistent with the traditional fundamental analysis where it is claimed that the financial statements contain firm values that may not be fully reflected In stock prices without delay. Despite the supporting empirical evidence. It is somewhat Inconclusive as to whether or not the abnormal return in excess of market return is the result of the extra knowledge obtained in the neural network models derived from the historical accounting data. This research attempts to open another avenue using neural network models for searching for evidence against market efficiency where statistics and intuition have played a major role.
An Analysis of the Media Effectiveness for Electronic Democracy
Journal of the Korean Operations Research and Management Science Society, volume 23, issue 4, 1998, Pages 225~234
little attention has been given to the analysis of electronic democracy media, although electronic democracy, if adopted in Korea, is expected to enhance the quality of the political culture to a large extent. This research is to compare electronic democracy media, such as Internet, cable TV, teleconferencing, fax, and ARS and suggest recommendations on the successful Introduction strategy of electronic democracy in Korea. The analysis of collected data yields research findings, such as the fact that internet will be the most effective medium and a strategy for popularizing internet needes to be developed in advance.