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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 32, Issue 4 - Dec 2007
Volume 32, Issue 3 - Sep 2007
Volume 32, Issue 2 - Jun 2007
Volume 32, Issue 1 - Mar 2007
Selecting the target year
Applying Ubi-SERVQUAL to Assessing the Quality of Ubiquitous Service Scenarios
Kwon, Oh-Byung ; Kim, Ji-Hoon ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 1~13
Nowadays, ubiquitous computing services begin to be suggested from a few domains such as supply chain, logistics, and location-based services. However, to what extent the services will be successful is hard to be estimated, mainly because a sophisticated service evaluation method focusing on the ubiquitous computing perspective has not been supplied. Hence, this paper alms to build a model to assess the quality of ubiquitous computing service. To do so, an amended model, Ubi-SERVQUAL, is applied to assess the service quality mentioned in ubiquitous computing scenarios. According to the Ubi-SERVQUAL, we found that an actual service with higher quality should consider reliability. responsiveness, assurance and empathy in order to increase customer satisfaction, computer system's intimacy with users and trust.
Sellers' Strategies in Online Auctions : Effect of Starting Bids and Buy-It-Now Options on Auction Outcomes
Lee, Ho-Mu ; Yoo, Ji-Hye ; Ahn, Byong-Hun ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 15~26
This study analyzes revenue-maximizing strategies of online auction sellers in terms of setting up starting bids and buy-it-now options. To this end, a series of field experiments is conducted where women's hair accessories of unique designs are listed in an established online auction site. The results of the experiments argue that high starting bids could increase sellers' revenue while buy-it-now options have no significant effects. Our findings suggest that online auction sellers listing items with uncertain demand - mainly individual sellers - should be cautious with auction tips which generally support low starting buds.
Effects of Adoption of the Buy-price, Setting the Starting Bid Price, and Adoption of 'the Effective Fixed Price' on the Final Bid Prices in Internet Auctions
Lee, Yong-Seon ; Ahn, Byong-Hun ; Jang, Dae-Chul ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 27~51
We analyze the effects of the sellers' strateiges on the final bid prices in internet auctions. We focus on the following three strategies of the seller adoption of the buy-price, setting the starting bid price, and adoption of 'the effective fixed price' which means that the starting bid price is set near the buy-price. In addition, the number of units sold single-unit or multi-unit, and item characteristics, such as whether the food is a search product (functional product) or an experience product (non-functional product), are also considered. We use real data on bids for 4 items from an online auction site. We find that in an auction for experience products when sold as single units, adopting the buy-price strategy raises the final bid price. We also find that in multi-unit auctions, starting the auction at 'the effective fixed price' raises the final bid price.
Heuristic Approach to the Mean Waiting Time of
Vacation Queues with N-policy and Setup Time
Lee, Sung-Hee ; Kim, Sung-Jin ; Chae, Kyung-Chul ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 53~60
We consider the discrete-time
queues under N-policy with multiple vacations (a single vacation) and setup time. In this queueing system, the server takes multiple vacations (a single vacation) whenever the system becomes empty, and he begins to serve the customers after setup time only if the queue length is at least a predetermined threshold value N. Using the heuristic approach, we derive the mean waiting time for both vacation models. We demonstrate that the heuristic approach is also useful for the discrete-time queues.
Design and Performance Measurement of a Genetic Algorithm-based Group Classification Method : The Case of Bond Rating
Min, Jae-H. ; Jeong, Chul-Woo ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 61~75
The purpose of this paper is to develop a new group classification method based on genetic algorithm and to com-pare its prediction performance with those of existing methods in the area of bond rating. To serve this purpose, we conduct various experiments with pilot and general models. Specifically, we first conduct experiments employing two pilot models : the one searching for the cluster center of each group and the other one searching for both the cluster center and the attribute weights in order to maximize classification accuracy. The results from the pilot experiments show that the performance of the latter in terms of classification accuracy ratio is higher than that of the former which provides the rationale of searching for both the cluster center of each group and the attribute weights to improve classification accuracy. With this lesson in mind, we design two generalized models employing genetic algorithm : the one is to maximize the classification accuracy and the other one is to minimize the total misclassification cost. We compare the performance of these two models with those of existing statistical and artificial intelligent models such as MDA, ANN, and Decision Tree, and conclude that the genetic algorithm-based group classification method that we propose in this paper significantly outperforms the other methods in respect of classification accuracy ratio as well as misclassification cost.
A Symbiotic Evolutionary Algorithm for Multi-objective Optimization
Shin, Kyoung-Seok ; Kim, Yeo-Keun ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 77~91
In this paper, we present a symbiotic evolutionary algorithm for multi-objective optimization. The goal in multi-objective evolutionary algorithms (MOEAs) is to find a set of well-distributed solutions close to the true Pareto optimal solutions. Most of the existing MOEAs operate one population that consists of individuals representing the entire solution to the problem. The proposed algorithm has a two-leveled structure. The structure is intended to improve the capability of searching diverse and food solutions. At the lower level there exist several populations, each of which represents a partial solution to the entire problem, and at the upper level there is one population whose individuals represent the entire solutions to the problem. The parallel search with partial solutions at the lower level and the Integrated search with entire solutions at the upper level are carried out simultaneously. The performance of the proposed algorithm is compared with those of the existing algorithms in terms of convergence and diversity. The optimization problems with continuous variables and discrete variables are used as test-bed problems. The experimental results confirm the effectiveness of the proposed algorithm.
An Integrated Control Problem of Secondary Sourcing and Inventory in A Supply Chain
Kim, Sung-Chul ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 93~104
We consider a supply chain where products are shipped to warehouse from manufacturing system to customers. Products are supplied from either in-house regular manufacturing or the secondary source such as subcontractor. The inventory in warehouse is controlled by base-stock policy, that is, whenever a demand arrives from customer, an order is released to the manufacturing system. Unsatisfied demand is backlogged. The manufacturing system is modeled as M/M/s+1/c queueing system, and the orders exceeding the given limit care blocked and lost. The steady state distribution of the outstanding orders and the throughput of the manufacturing system are functions of the level of engagement In the secondary source. There is a profit obtained from throughput and cost not only due to the engagement of the secondary source in the manufacturing system but also inventory positions. We want to maximize the total production profit minus the total cost of the production system by simultaneously determining the optimal level of engagement of the secondary source and the optimal base-stock level of the inventory. We develop two algorithms : one without guarantee of the optimal solution but with the small number of computations, the other optimal but with more computations.
A Study on the Current Customer's Defection Due to Promotions Focused on New Customer Acquisition
Lee, Ki-Soon ; Kim, Sang-Yong ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 105~124
CRM (Customer Relationship Management) becomes a crucial paradigm as the environment of the market changes. About the CRM actively maintaining and managing customers that have been already acquired, the research has been done as a plan to lure loyal customers who bring lucrative profits in the long term for the company in order to increase the value to the customers. However, in practice, the focus is on putting spurs to attracting new customers in a short term rather than retaining existing customers who give profitable revenues. If the company puts high emphasis on drawing the new customers, in a CRM's point of view in relation to the value of the customers, it can incur a loss in the long run. The reason is that if the firm conducts discriminative sales promotion, the existing clients with high loyalty will feel relatively treated inappropriately and they will have negative feelings such as being betrayed from the company they prefer. This occurrence of negative emotion can in-crease the possibility of highly profitable clients' secession. In consequence, this paper focusing on the process of the client segmentation at the mobile telecommunication services shows that the sales promotion strategy for the new customer attraction can lead to negative effect on the loyalty of the existing customers.
Relaxing Queries by Combining Knowledge Abstraction and Semantic Distance Approach
Shin, Myung-Keun ; Park, Sung-Hyuk ; Lee, Woo-Key ; Huh, Soon-Young ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 125~136
The study on query relaxation which provides approximate answers has received attention. In recent years, some arguments have been made that semantic relationships are useful to present the relationships among data values and calculating the semantic distance between two data values can be used as a quantitative measure to express relative distance. The aim of this article is a hierarchical metricized knowledge abstraction (HiMKA) with an emphasis on combining data abstraction hierarchy and distance measure among data values. We propose the operations and the query relaxation algorithm appropriate to the HiMKA. With various experiments and comparison with other method, we show that the HiMKA is very useful for the quantified approximate query answering and our result is to offer a new methodological framework for query relaxation.
Order Based Performance Evaluation of a CONWIP System with Compound Poisson Demands
Park, Chan-Woo ; Lee, Hyo-Seong ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 137~146
In this study we consider a CONWIP system studied in Park and Lee  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 using the results in  we develop an approximation method to calculate order based performance measures such as the mean time of fulfilling a customer order and the mean number of customer orders. 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 have shown that the approximate method provides fairly good results.
The Decision Making Strategy for Determining the Optimal Production Time : A Stochastic Process and NPV Approach
Choi, Jong-Du ;
Journal of the Korean Operations Research and Management Science Society, volume 32, issue 1, 2007, Pages 147~160
In this paper, the optimal decision making strategy for resource management is viewed in terms of a combined strategy of planting and producing time. A model which can be used to determine the optimal management strategy is developed, and focuses on how to design the operation of a Markov chain so as to optimize its performance. This study estimated a dynamic stochastic model to compare alternative production style and used the net present value of returns to evaluate the scenarios. The managers in this study may be able to increase economic returns by delaying produce in order to market larder, more valuable commodities.