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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 12, Issue 2 - Dec 1987
Volume 12, Issue 1 - Apr 1987
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The (S -1 , S) Inventory Model with Drder Size Dependent Dilivery Times
Kang, SukHo ; Park, Jeonghun ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 1~9
This paper considers (S -1, S) inventory models which have wide applications in reparable spare parts inventory systems and multi-echelon systems. We assume a discrete compounds Poisson demand and order size dependent delivery times ; when the replenishment order size is n, we assume the delivery time distribution is arbitrary with finite mean
. On the basis of the fact the outstanding orders follow a certain queueing process, we introduce the results of Fakinos (1982). We develop the efficient recursive formulae to find the optimal
under several performance measures as a function of the decision variable S. The results of this paper can be applied to the multi-echelon systems such as MEETRIC.C.
Algorithmic Properties of Isotone Complementarity Problems
Ahn, Byong-Hun ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 10~18
This paper discusses algorithmic properties of a class of complementarity programs involving strictly diagonally isotone and off-diagonally isotone functions, i. e., functions whose Jacobian matrices have positive diagonal elements and nonnegative off-diagonal elements, A typical traffic equilibrium under elastic demands is cast into this class. Algorithmic properties of these complementarity problems, when a Jacobi-type iteration is applied, are investigated. It is shown that with a properly chosen starting point the generated sequence are decomposed into two converging monotonic subsequences. This and related will be useful in developing solution procedures for this class of complementarity problems.
An Adaptive Structural Model When There is a Major Level Change
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 19~26
In analyzing time series, estimating the level or the current mean of the process plays an important role in understanding its structure and in being able to make forecasts. The studies the class of time series models where the level of the process is assumed to follow a random walk and the deviation from the level follow an ARMA process. The estimation and forecasting problem in a Bayesian framework and uses the Kalman filter to obtain forecasts based on estimates of level. In the analysis of time series, we usually make the assumption that the time series is generated by one model. However, in many situations the time series undergoes a structural change at one point in time. For example there may be a change in the distribution of random variables or in parameter values. Another example occurs when the level of the process changes abruptly at one period. In order to study such problems, the assumption that level follows a random walk process is relaxed to include a major level change at a particular point in time. The major level change is detected by examining the likelihood raio under a null hypothesis of no change and an alternative hypothesis of a major level change. The author proposes a method for estimation the size of the level change by adding one state variable to the state space model of the original Kalman filter. Detailed theoretical and numerical results are obtained for th first order autoregressive process wirth level changes.
An One-for-One Ordering Inventory Policy with Poisson Demands and Losses with Order Dependent Leadtimes
Choi, Jin-Yeong ; Kim, Man-Sik ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 27~33
A stochastic model for an inventory system in which depletion of stock takes place due to random demand as well as random loss of items is studied under the assumption that the intervals between cussessive unit demands as well as those between cussessive unit losses, are independently and identically distributed random variables having negative exponential distributions with respective parameters .mu. and .lambda. It is further assumed that leadtime for each order is an outstanding-order-dependent random variable. The steady state probability distribution of the net inventory level is derived under the continuous review (S -1, S) inventory policy, from which the total expected coast expression is formulated.
An Exact Algorithm for the Asymmetrical Vehicle Routing Problem
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 34~44
The general vehicle routing problem has been studied by many researchers such as Christofides, et al. and Laporte, et al., but only limited effort has been devoted to developing the optimal algorithms. The purpose of this paper is to develop a branch and bound algorithm which determines the optimal vechicle routes and the optimal number of vehicles concurrenetly for the asymmetrical vehicle routing problem. In order to enhance the efficiency, this algorithm emphasizes the followings ; First, an efficient primal-dual approach is developed to solve subproblems which are called the specialized transportation problem, formed by relaxing the illegal subtour constraints from the vehicle routing problem, second, an improved branching scheme is developed to reduce the number of candidate subproblems by adequate utilization of vehicle capacity restrictions.
A Study on the establishment of EDI System in Korea sea trade
최상모 ; 장병만 ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 95~95
The purpose of this research is to suggest a desirable framework to promote EDI system in the Korean trade and transportation industries. First, this thesis reviews the trend of introduction of EDI systems in foreign countries and investigates their characteristics by examining some cases. Then the problems, which the Korean industries would be confronted with during the course of introduction of EDI system, are identified and discussed. Finally, this thesis suggests that the logistics network should be developed as a main system of EDI to which sub-networks of trade and custom service are linked. This leading role of logistics metwork is necessary to the EDI system because logistics tasks for international movement of goods are expected to increase while tasks related to trade and custom services will decrease in view of recent changes in the world trade environments warning the unbounded competition in the global marketplace without border.
SUPPLEMENTARY ANALYSES OF ECONOMIC X CHART MODEL
Jeon,Tae Bo ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 111~111
With the increasing interest of reducing process variation, statistical process control has served the pivotal tool in most industrial quality programs. In this study, system analyses have been performed associated with a cost incorporated version of a process control, a quadratic loss-based X over bar control chart model. Specifically, two issues, the capital/research investments for improvement of a system and the precision of a parameter estimation, have been addressed and discussed. Through the analysis of experimental results, we show that process variability is seen to be one of the most important sources of loss and quality improvement efforts should be directed to reduce this variability. We further derive the results that, even if the optimal designs may be sensitive, the model appears to be robust with regard to misspecification of parameters. The approach and discussion taken in this study provide a meaningful guide for proper process control. We conclude this study with providing general comments.
Design and Implementation of Mathematical Programming Software-LinPro
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 139~139
This study addresses basic requirements for mathematical programming software, discusses considerations in designing these software, implementation issues facing in these types of applications development, and shows some examples of codes being developed in the course. This type of projects requires long and ever-changing evolutionary phases. The experience is therefore, valuaable in suggesting some useful hints which may be salvaged for similar projects as well as providing reusable codes. In particular, scanning and parsing the free-format inputs, symbol table management, mixed-language programming, and data structures dealing with large sparse matrices are indispensable to many management science software development. Extensions to be made are also discussed.
A Framework for Investment Justification and Economic Operation-
이승규 ; 박용삼 ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 157~157
Hydro-electric power generation from multi-purpose dams has been playing important roles in the electric power supply network in Korea. Although the total share of hydro power in national electricity supply now becomes very small, the peak-shaving and frequency control capability of hydro power helps the power company enormously in maintaining the quality of power. But since the company that builds and operates the multi-purpose dams in Korea has to sell all the electricity produced to the monopolistic utility, there have been various problems in justifying the investment, designing pricing mechanism, and controlling operations of the power plants. In addition, economic evaluation of the hydro power has been distorted by a variety of reasons and hence it has been very difficult to encourage effective development and utilization of national water resources. To make the problem worse, both parties are public companies with X-inefficiency problems. Thus, changing environment requires to reengineer the system that governs hydro power generation. We address the problems of Korean hydro-electric power generation system in four areas: the investment justification process, the operations decison right of the hydro power plants, the pricing of the purchased-power, and the negotiation of contract revision. Then we propose improvement directions of new hydro-electric power system in view of static and dynamic efficiency, X-inefficiency and equity.
Business Reengineering of Order-Taking and Purchasing Processes : A Case Study
최무진 ; 장상구 ;
Journal of the Korean Operations Research and Management Science Society, volume 12, issue 1, 1987, Pages 175~175
Business reengineering (BR) is an emerging idea that attempts to restructure inefficient, current business processes through redesigning jobs and exploiting new information technology (IT), and helps achieving significant improvements in white-collar productivity and returns of IT investment. This research analyzed order-taking and purchasing processes of a company (a coil distributor) using BR concepts, models and principles. We also made proposals for reengineering the present business processes. For this, BR literatures were reviewed to derive BR models and principles to be used for analyses. We applied these ideas to six(6) types of order-taking and purchasing processes of Company T. For each type, current processes, BR analyses, and proposals for BR were described. Finally, findings were summarized and discussed.