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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 34, Issue 4 - Dec 2009
Volume 34, Issue 3 - Sep 2009
Volume 34, Issue 2 - Jun 2009
Volume 34, Issue 1 - Mar 2009
Selecting the target year
An Analysis on M&A Performance of Global Steel Companies through Competitiveness Variables
Huh, Kwang-Sook ; Kim, Jin-Han ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 1~14
This study empirically tests post-M&A performance through competitiveness variables based on extensive firm-based panel data over the past 26 years in the world steel industry. Different measures of profitability, productivity, efficiency, market share, and growth rate which are considered as critical factors of competitiveness are used in the analysis. In particular, this paper tries to separate M&A samples into two cases; horizontal integration (between steel makers) and vertical integration (between steel makers and iron ore suppliers/steel consuming firms). Merged firms show significant improvement in competitiveness relative to other individual firms in the steel industry.
Two Pieces Extension of the Bass Diffusion Model
Hong, Jung-Sik ; Eom, Seok-Jun ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 15~26
Bass diffusion model have played a central role in studying the diffusion of the new products since 1969, the year of publication of Bass model. Almost 750 publications based on the Bass diffusion model have explored extensions and applications. Extension models can be divided into two types. One is the model containing marketing-mix variables and the other is the model containing additional parameters. This paper presents another extension model of the latter type. Our model allows the time varying coefficients of innovation and imitation. Two pieces approximation of time varying coefficients is introduced and it's parameters are estimated based on NLS(Non-Linear Mean Square) method. Empirical studies are performed and the results show that our model is superior to the basic Bass model and the NUI(Non-Uniform Influence) model which is the well-known extension of the Bass model. The model developed in this paper is, also, transformed into the Bass model with the ready potential adopters in order to enhance the descriptive power.
Factors Affecting Awareness and Usage of Government Export Marketing Assistance Programs and Their Relationships
Lee, Chol ; Kim, Sang-Yong ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 27~42
The research aims to identify factors affecting the use of government export marketing assistance programs and future improvements of the programs. 500 Korean exporting firms were used as a sample and research hypotheses were tested by the structural equation modeling using AMOS 7.0. The empirical findings are as follows. First, exporting firms' awareness of export marketing assistance programs showed a positive impact on their use of the programs. Second, small exporters showed higher awareness and use of the programs than large ones. Third, the firms with low export intensity showed higher awareness and use of the programs than those with high export intensity. Fourth, exporters having high orientations for overseas market showed higher awareness and use of the programs than those with low international orientations. Fifth, exporters having high proportion of direct exports showed higher awareness and use of the programs than those with low proportion of direct exports. Also, the effects of these firm-specific characteristics on the use of the programs were found to be done indirectly, in other words, through the awareness of the programs. Therefore, it was concluded that export marketing assistance program would be differentiated and specialized to fit in with exporters' different exporting stages and needs. Also, in order to increase the use of the programs, exporters' awareness and knowledge of the programs have to be increased in advance.
The Optimal Allocation Model for SAM Using Multi-Heuristic Algorithm : Focused on Aircraft Defense
Kwak, Ki-Hoon ; Lee, Jae-Yeong ; Jung, Chi-Young ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 43~56
In korean peninsular, aircraft defense with SAM (Surface-to-Air Missile) is very important because of short range of combat space in depth. Effective and successful defense operation largely depends on two factors, SAM's location and the number of SAM for each target based on missile's availability in each SAM's location. However, most previous papers have handled only the former. In this paper, we developed Set covering model which can handle both factors simultaneously and Multi-heuristic algorithm for solving allocation problem of the batteries and missile assignment problem in each battery. Genetic algorithm is used to decide optimal location of the batteries. To determine the number of SAM, a heuristic algorithm is applied for solving missile assignment problem. If the proposed model is applied to allocation of SAM, it will improve the effectiveness of air defense operations.
Product Network Analysis to Analyze the Purchase Behavior of Customers
Choi, II-Young ; Kim, Jae-Kyeong ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 57~72
As development of information technologies, customer retention has been an important issue in the competing environment. A lot of researches focus on prediction of the churning customers and seeking their characteristics. However, relationships among customers or products have not been considered in existing researches. In this study, product networks are proposed and analyzed to investigate the differences of network characteristics of products purchased by potential churning customers and those of loyal customers. The product networks are constructed from real product purchase data collected from a Korean department store. We investigated the characteristic differences, such as the degree centrality, degree centralization, and density, of two product networks constructed by potential churning customers and the loyal customers. The results indicate that degree centrality, density and degree centralization of the product network of the loyal customers are higher than those of the potential churning customers. And the promotional products of the department store are resulted to be effective in attracting the loyal customers.
An Optimization Model for Resolving Circular Shareholdings of Korean Large Business Groups
Park, Chan-Kyoo ; Kim, Dae-Lyong ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 73~89
Circular shareholdings among three companies are formed when company A owns stock in company B, company B owns stock in company C, and company C owns stock in company A. Since circular shareholdings among large family-controlled firms are used to give the controlling shareholder greater control or more opportunities to expropriate minority investors, the government has encouraged large business groups to gradually remove their circular shareholdings. In this paper, we propose a combinatorial optimization model that can answer the question, which equity investments among complicated investment relationships of one large business group should be removed to resolve its circular shareholdings. To the best knowledge of the authors, our research is the first one that has approached the circular shareholding problem in respect of management science. The proposed combinatorial optimization model are formulated into integer programming problem and applied to some Korean major business groups.
Developing the Bullwhip Effect Measure in a Supply Chain Considering Seasonal Demand and Stochastic Lead Time
Cho, Dong-Won ; Lee, Young-Hae ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 91~112
The bullwhip effect means the phenomenon of increasing demand variation as moving UP to the upstream in the supply chain. Therefore, it is recognized that the bullwhip effect is problematic for effective supply chain operations. In this paper, we exactly quantifies the bullwhip effect for the case of stochastic lead time and seasonal demand in two-echelon supply chain where retailer employs a base-stock policy considering SARMA demand processes and stochastic lead time. We also investigate the behavior of the proposed measurement for the bullwhip effect with autoregressive and moving average coefficient, stochastic lead time, and seasonal factor.
A Study of Departure Process on the Open and Nested Population Constrained Tandem Queueing Network with Constant Service Times
Rhee, Young ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 113~121
In this paper, we consider the departure process from the open and nested tandem Queueing network with population constraint and constant service times. It is known that the Queueing network can be transformed into a simple Queueing network which can be easy to analyze. Using this simple Queueing network, upper and lower bounds on the interdeparture time are obtained. We prove that the variance of the interdeparture time is bounded within these two bounds. Validation against simulation data is shown that how it works the variance of the interdeparture time within two bounds. These bounds can be applied to obtain the better variance of the interdeparture time using a suitable method.
First- and Second-best Pricing in Stable Dynamic Models
Park, Koo-Hyun ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 123~138
This study examined the first- and second-best pricing by stable dynamics in congested transportation networks. Stable dynamics, suggested by Nesterov and de Palma (2003), is a new model which describes and provides a stable state of congestion in urban transportation networks. The first-best pricing in user equilibrium models introduces user-equilibrium in the system-equilibrium by tolling the difference between the marginal social cost and the marginal private cost on each link. Nevertheless, the second-best pricing, which levies the toll on some, but not all, links, is relevant from the practical point of view. In comparison with the user equilibrium model, the stable dynamic model provides a solution equivalent to system-equilibrium if it is focused on link flows. Therefore the toll interval on each link, which keeps up the system-equilibrium, is more meaningful than the first-best pricing. In addition, the second-best pricing in stable dynamic models is the same as the first-best pricing since the toll interval is separately given by each link. As an effect of congestion pricing in stable dynamic models, we can remove the inefficiency of the network with inefficient Braess links by levying a toll on the Braess link. We present a numerical example applied to the network with 6 nodes and 9 links, including 2 Braess links.
Production and Shipment Lot Sizing in a Vendor-Buyer Supply Chain with Freight Cost Discounts
Kim, Chang-Hyun ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 139~151
Based on single-vendor single-buyer integrated production-inventory problem, a model considering freight costs discounts is suggested when the cargo capacity is constrained. With the cost function formulated, several properties of the model are derived and analyzed. An efficient algorithm to find solutions such as shipment lot size, number of shipments and number of full truckloads using properties derived is suggested. Numerical results are provided to illustrate the proposed solution procedures and to provide additional insights.
An Efficient Algorithm to Find Portfolio Weights for the First Degree Stochastic Dominance with Maximum Expected Return
Ryu, Choon-Ho ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 153~163
Unlike the mean-variance approach, the stochastic dominance approach is to form a portfolio that stochastically dominates a predetermined benchmark portfolio such as KOSPI. This study is to search a set of portfolio weights for the first-order stochastic dominance with maximum expected return by managing the constraint set and the objective function separately. A nonlinear programming algorithm was developed and tested with promising results against Korean stock market data sets.
The Effects of Servicescape and Service Process Quality on Employee and Customer Satisfaction : An Empirical Investigation of the Golf Course Business in Korea
Lim, Jae-Poung ; Lee, Youn-Suk ; Park, Myung-Sub ; Shin, Ho-Jung ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 165~183
In a service process, the customer typically experiences two types of interactions; one is interaction with the physical ambiance (servicescape) and the other is with employees who may be responsible for the service process quality. The literature in general supports that process quality is a critical determinant for overall service quality and customer satisfaction. In this paper, we primarily examine how the servicescape intervenes the association between process quality and employee/customer satisfaction. The proposed models are tested. using the data collected from the major golf courses in Korea. The results suggest that improving process quality and servicescape have a positive influence on employee/customer satisfaction directly and/or indirectly, but the effect of servicescape may be stronger in the case of golf course businesses. Servicescape also contributes to improving process quality by enhancing employee satisfaction. These results collectively indicate that management emphasis on improving service quality without renovating physical surroundings may results in unsatisfactory outcome.
An Optimal Strategy of 3G Mobile Handset Distribution by 3-Person Game
Joo, Young-Jin ; Moon, Hyoung-Don ;
Journal of the Korean Operations Research and Management Science Society, volume 34, issue 4, 2009, Pages 185~204
The USIM(universal subscriber identity module)-unlock introducing in July 1, 2008 might be led to a significant change that mobile service provider's dominance is considerably dispersed to the handset manufacturer and distributor. Under USIM-unlock environment, mobile service provider, handset manufacturer, and distributor have to make their decisions on their handset distribution channel strategies: the closed distribution channel strategy or the open distribution channel strategy. The change of distribution channel strategy between members in distribution channel can be understood as a matter of strategy choice, and we have developed a theoretical model and analyzed how to make a decision for the member's optimal distribution strategy based on 3-person game model between members of mobile phone distribution channel, under both of '1 subscriber-1 handset' and '1 subscriber-multiple handset' assumptions. Under '1 subscriber-1 handset' assumption, the closed strategy controlled by mobile service provider is all players' optimal solution because the maximum size of the mobile phone market is limited by subscribers. But, as total expected profit by the handset and distribution subsides is a deficit, mobile service provider have to choose the open strategy and consider the conversion to MNO(mobile network operator). Under '1 subscriber-multiple handset' assumption, mobile service provider is trying to find the way how to lock-in its service and mobile phone and how to maximize ARPU(average revenue per unit), while handset manufacturer and distributor have to look for the way how to maximize the mobile phone market using their own marketing efforts, because it is expected that total mobile handset demand for the open market is bigger than demand for the closed market under '1 subscriber-multiple handset' assumption.