Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Operations Research and Management Science Society
Journal Basic Information
Journal DOI :
The Korean Operations and Management Science Society
Editor in Chief :
Volume & Issues
Volume 31, Issue 4 - Dec 2006
Volume 31, Issue 3 - Sep 2006
Volume 31, Issue 2 - Jun 2006
Volume 31, Issue 1 - Mar 2006
Selecting the target year
Optimal Soft-combine Zone Configuration in a Multicast CDMA Network
Kim Jae-Hoon ; Myung Young-Soo ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 1~10
In this paper we deal with a cell planning issue arisen in a CDMA based multicast network. In a CDMA based wireless network, a terminal can significantly reduce the bit error rate via the cohesion of data streams from multiple base stations. In this case, multiple base stations have to be operated according to a common time line. The cells whose base stations are operated as such are called soft-combined cells. Therefore, a terminal can take advantage of error rate reduction, if the terminal is in a soft-combined cell and at least one neighboring cell is also soft-combined. However, as soft-combining operation gives heavy burden to the network controller, the limited number of cells can be soft-combined. Our problem us to find a limited number of soft-combined cells such that the benefit of the soft-combining operation is maximized.
Allocating Storage Spaces for Temporary Inventories Considering Handling, Transportation, and Storage Capacities
Won Seung-Hwan ; Kim Kap-Hwan ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 11~25
Space may be a scarce resource in manufacturing shops, warehouses, freight terminals, and container terminals. This Paper discusses how to locate temporary storage Inventories In limited storage areas. A typical inventory is delivered from the location of the preceding process to the storage area and stored In the storage area during the certain period of time. And it may be relocated from the storage position to another. Finally. it is delivered from the final storage area to the location of the next process. Because this logistic process for an inventory requires handling activities, transportation activities, and storage spaces, the limitation in capacities of handling equipment, transportation equipment, and storage space must be considered when allocating spaces to the inventory. This problem Is modeled as a multicommodity minimal cost flow problem. And a heuristic algorithm for the Problem is proposed. Numerical experiments are presented to validate the mathematical model and the heuristic algorithm.
An Adaptive Vendor Managed Inventory Model Using Action-Reward Learning Method
Kim Chang-Ouk ; Baek Jun-Geol ; Choi Jin-Sung ; Kwon Ick-Hyun ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 27~40
Today's customer demands in supply chains tend to change quickly, variously even in a short time Interval. The uncertainties of customer demands make it difficult for supply chains to achieve efficient inventory replenishment, resulting in loosing sales opportunity or keeping excessive chain wide inventories. Un this paper, we propose an adaptive vendor managed inventory (VMI) model for a two-echelon supply chain with non-stationary customer demands using the action-reward learning method. The Purpose of this model is to decrease the inventory cost adaptively. The control Parameter, a compensation factor, is designed to adaptively change as customer demand pattern changes. A simulation-based experiment was performed to compare the performance of the adaptive VMI model.
A Clustering Algorithm Using the Ordered Weight of Self-Organizing Feature Maps
Lee Jong-Sup ; Kang Maing-Kyu ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 41~51
Clustering is to group similar objects into clusters. Until now there are a lot of approaches using Self-Organizing feature Maps (SOFMS) But they have problems with a small output-layer nodes and initial weight. For example, one of them is a one-dimension map of c output-layer nodes, if they want to make c clusters. This approach has problems to classify elaboratively. This Paper suggests one-dimensional output-layer nodes in SOFMs. The number of output-layer nodes is more than those of clusters intended to find and the order of output-layer nodes is ascending in the sum of the output-layer node's weight. We un find input data in SOFMs output node and classify input data in output nodes using Euclidean distance. The proposed algorithm was tested on well-known IRIS data and TSPLIB. The results of this computational study demonstrate the superiority of the proposed algorithm.
Analysis of Pricing Strategies and Business Models in Online Content Market
Chun Se-Hak ; Kim Jae-Cheol ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 53~62
Many information providers in the electronic market struggle to attain revenue from their information goods including contents or other services and they tend to charge for their contents or services since they are confronted with difficulties in attaining revenue from online advertising. This study examines why they begin to charge for their contents or services and explores Pricing strategies for their contents. Also, this paper explores business strategies when conventional offline contents firms enter the online contents market and draws some implications for the condition of entry of offline contents providers into the online market.
Performance Evaluation of a CONWIP System with Compound Poisson Demands and Coxian Processing Times
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 63~79
In this study we consider a CONWIP system in which the processing times at each station follow a Coxian distribution and the demands for the finished products arrive according to a compound Poisson process. The demands that are not satisfied immediately are either backordered or lost according to the number of demands that exist at their arrival Instants. For this system we develop an approximation method to calculate performance measures such as steady state probabilities of the number of parts at each station, proportion of lost demands and the mean number of backordered demands. For the analysis of the proposed CONWIP system, we model the CONWIP system as a closed queueing network with a synchronization station and analyze the closed queueing network using a product-form approximation method. A recursive technique is used to solve the subnetwork in the application of the product-form approximation method. To test the accuracy of the approximation method, the results obtained from the approximation method are compared with those obtained by simulation. Comparisons with simulation show that the approximation method provides fairly good results.
Rental Resource Management Model with Capacity Expansion and Return
Kim Eun-Gab ; Byun Jin-Ho ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 81~96
We consider a rental company that dynamically manages Its capacity level through capacity addition and return While serving customer with its own capacity, the company expands its capacity by renting items from an outside source so that it can avoid lost opportunities of rental which occur when stock is not sufficient. If stock becomes sufficiently large enough to cope with demands, the company returns expanded capacity to the outside source. Formulating the model into a Markov decision problem, we identify an optimal capacity management Policy which states when the company should expand its capacity and when it should return expanded capacity after capacity addition. Since it is intractable to analytically find the optimal capacity management policy and the optimal size of capacity expansion, we present a numerical procedure that finds these optimal values based on the value iteration method. Numerical analysis is implemented and we observe monotonic properties of the optimal performance measures by system parameters, which are meaningful in developing effective heuristic policies
A Dynamic Pricing Model with a Multiplicative Functional Form
Cha Kyoung-Cheon ; Jun Duk-Bin ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 97~105
Brand Pricing is the most important issue for the brand manager in the dynamic market. in the typical dynamic pricing model, a linear function has been used based on the assumption that the non-Price Influences and the price influences were independent. However, to incorporate the characteristics of the dynamic market, it is natural to consider the multiplicative relationship. We are going to try the multiplicative linkage between the non-price Influences and the price influences and suggest a new dynamic pricing model with e multiplicative functional form. An empirical study of 19 brands in the Korean cigarette market shows the feasibility of the suggested model.
A Study on Product Positioning based on Conjoint Analysis in a Competitive Market
Baek Seung-Kee ; Rhim Ho-Sun ; Park Myung-Sub ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 107~125
We introduce a two-stage game theoretic model to support decision making processes for product Positioning and pricing in competitive environment. In the first stage, firms decide on entry and product position, in the second stage, firms compete with price. 'Alpha rule' is used as a choice model. Demand parameters of the choice model are estimated by conjoint analysis. We investigate conditions for the existence of Nash price equilibria in the pricing game. Nash equilibria in the entry and positioning game are produced using a concept of stable sets. An example of the online game industry in Korea is examined.
Self-Directed Learning and e-Learning Environment Satisfaction : Comparison Analysis by Self-Regulated Efficacy
Lee Woong-Kyu ; Lee Jong-Ki ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 127~143
While e-learners' satisfaction would be determined by qualify of e-learning environment including learning management systems, learning contents and interactions, the influence of quality on satisfaction can be changed by e-learners' self-regulated efficacy The objective of this study is to show difference of the relationship between qualify and satisfaction In e-learning by self-regulated efficacy. For this purpose, we propose a research model which consists of five quality factors in e-learning as explaining variables, satisfaction as a result variable and self-regulated efficacy as a control variable. For empirical test of this model, the sample is collected from e-learning classes in a college and divided into two groups by self-regulated efficacy in order to analyze the effects of control variable. By multi-group analysis, we show two groups are different from each other in the relationship between quality and satisfaction of e-learning environment.
Study of Radio Resource Allocation Method for Wireless Broadband Internet System
Kook Kwang-Ho ; Kim Kyung-Hee ; Baek Jang-Hyun ;
Journal of the Korean Operations Research and Management Science Society, volume 31, issue 3, 2006, Pages 145~154
WiBro (Wireless Broadband Internet) system is going to be 9ot down to commercialization. The high portable internet system is able to be connected to the high-speed internet using 2.3 GHz frequency bandwidth, anytime and anywhere. An effective scheduling for UGS, rtPS, nrtPS and BE requiring different QoS, which are service types of the WiBro, is necessary to increase the efficiency of radio channels that are the limiting resource. This paper researches an uplink scheduling that plays a role in assignment for the radio channels from subscribers to base stations. The suggested scheduling provides priorities with each service type considering QoS of them but reserves some bandwidth for lower priory services. After deciding effective amount of bandwidth for reservation, we suggest analytical result on mean delayed time of packet transmission for each terminal, transmission rate for the data, and capacity for uplink. This research can be used as basic data for the standard in the high portable internet system and as data to predict the capacity of base stations.