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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 39, Issue 4 - Nov 2014
Volume 39, Issue 3 - Sep 2014
Volume 39, Issue 2 - Jun 2014
Volume 39, Issue 1 - Mar 2014
Selecting the target year
A Study on a Way to Utilize Big Data Analytics in the Defense Area
Kim, Seong-Woo ; Kim, Gak-Gyu ; Yoon, Bong-Kyu ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 1~19
DOI : 10.7737/JKORMS.2014.39.2.001
Recently, one of the core keywords in information technology (IT) as well as areas such as business management is big data. Big data is a term that includes technology, personnel, and organization required to gather/manage/analyze collection of data sets so large and complex that it becomes difficult to manage and analyze using traditional tools. The military has been accumulating data for a long period due to the organization`s characteristic in placing emphasis on reporting and records. Considering such characteristic of the military, this study verifies the possibility of improving the performance of the military organization through use of big data and furthermore, create scientific development of operation, strategy, and support environment. For this purpose, the study organizes general status and case studies related to big data, traces back examples of data utilization by Korean`s national defense sector through US military data collection and case studies, and proposes the possibility of using and applying big data in the national defense sector.
Impact of Logistics Costs on Supply-Chain Flexibility Structure
Nam, Jin Mo ; Park, Kun Soo ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 21~35
DOI : 10.7737/JKORMS.2014.39.2.021
As productions and deliveries of multiple products to multiple marketplaces have been increasingly popular, supply chain flexibility, which refers to an ability to deal with demand and capacity uncertainty, becomes an important issue in supply chain management. However, logistics costs have been largely neglected in the literature on supply chain flexibility structure. In this paper, we propose mathematical models to investigate the impact of the logistics costs on the optimal flexibility structure. We also conduct a simulation study and observe that logistics costs have a significant impact on the decision on supply chain flexibility structure. Such conclusion is also supported by the case study of a global car manufacturer, Honda Motors.
A Study of Flight Scheduling Problem on Fighter Squadron
Lee, Moongul ; Seo, Sanghoon ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 37~48
DOI : 10.7737/JKORMS.2014.39.2.037
Fighter squadron flight scheduling is the integrated air operation plan that is an important role for improving pilot`s flight skill and maintaining combat readiness by efficient using available all air resources including pilot, aircrafts, air-weapons, fuel and supporting facilities etc. Korea airforce, however, has a limit as to an effective flight operation due to manual flight scheduling with scheduler`s own experience and intuition. Therefore, in our study, we propose the optimization model of flight scheduling based on mixed integer programming. This model includes several constraints of realistic and essential quantified data related with flight schedule and can assign appropriate pilots optimally which are distinctive three type`s solutions : flight, alert and duty crew schedules. Proposed solution method can be improved pilot`s capability and allocated further air resources systematically and efficiently. In addition, it can be reduced a workload of flight scheduler and minimized obstructed factors of flight safety. Finally, we demonstrate the experiment`s results for the check of efficiency and validity of this model.
Portfolio Management with the Business Cycle and Bayesian Learning
Park, Seyoung ; Lee, Hyun-Tak ; Rhee, Yuna ; Jang, Bong-Gyu ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 49~66
DOI : 10.7737/JKORMS.2014.39.2.049
This paper studies optimal consumption and investment behaviors of an individual when risky asset returns and her income are affected by the business cycle. The investor considers the incomplete information risk of unobservable macroeconomic conditions and updates her belief of expected risky asset returns through Bayesian learning. We find that the optimal investment strategy, certainty equivalent wealth, and portfolio hedging demand significantly depend on the belief about the macroeconomic conditions.
The Relationship between Win-Win Growth Effort and Financial Performance with Time-lag : Development of Win-Win Growth Index using Ordered Probit Model
Min, Jae H. ; Kim, Bumseok ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 67~82
DOI : 10.7737/JKORMS.2014.39.2.067
The purpose of this study is two-fold : the one is to examine the causal relationship between domestic large firms` win-win growth effort and their financial performance by fiscal years; and the other is to develop a quantitative win-win growth index to overcome the limitation of the current one mainly using a survey method developed by NCCP (National Commission for Corporate Partnership). To serve the first purpose, we take a sample of 128 large companies whose win-win growth indices as of year 2011 and 2012 were evaluated by NCCP. We use their respective fiscal year`s financial data to select 62 candidate financial ratios, which are then used in subsequent empirical tests. For the tests, we employ ordered probit model with stepwise selection method and two-way ANOVA with randomized block design to identify which of the 62 financial ratios are statistically significant ones to affect the firms` win-win growth index as well as to determine if the firms` win-win growth effort would cause their financial performance positively. To serve the second purpose, we devise a model using the 123 firms` 45 financial ratios, which employs ordered probit model with stepwise selection, and the validation of the model follows. We claim that the model suggested in this study serve as an alternative complementing the current one as it can produce the index in a more objective and swift manner using the firms` publicized financial statements.
Development and Evaluation of a Portfolio Selection Model and Investment Algorithm in Foreign Exchange Market
Choi, Jaeho ; Jung, Jongbin ; Kim, Seongmoon ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 83~95
DOI : 10.7737/JKORMS.2014.39.2.083
In this paper, we develop a portfolio selection model that can be used to invest in markets with margin requirements such as the foreign exchange market. An investment algorithm to implement the proposed portfolio selection model based on objective historical data is also presented. We further conduct empirical analysis on the performance of a hypothetical investment in the foreign exchange market, using the proposed portfolio selection model and investment algorithm. Using 7 currency pairs that recorded the highest trading volume in the foreign exchange market during the most recent 10 years, we compare the performance of 1) the Dollar Index, 2) a 1/N Portfolio which equally allocates capital to all N assets considered for investment, and 3) a hypothetical investment portfolio selected and managed according to the portfolio selection model and investment algorithm proposed in this paper. Performance is compared in terms of accumulated returns and Sharpe ratios for the 10-year period from January 2003 to December 2012. The results show that the hypothetical investment portfolio outperforms both benchmarks, with superior performance especially during the period following financial crisis. Overall, this paper suggests that a mathematical approach for selecting and managing an optimal investment portfolio based on objective data can achieve outstanding performance in the foreign exchange market.
Managing Inventories of Brand-New and Recovered Products in a Reverse Supply Chain with Downward Demand Substitution
Kim, Eungab ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 97~109
DOI : 10.7737/JKORMS.2014.39.2.097
This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system`s profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.
Development and Application of Effect Measurement Tool for Victory Factors in Offensive Operations Using Big Data Analytics
Kim, Gak-Gyu ; Kim, Dae-Sung ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 111~130
DOI : 10.7737/JKORMS.2014.39.2.111
For the key factors determining victory of combat, many works have been focusing on qualitative analyses in the past. As military training paradigm changes along with technology developments, demands for scientific analysis to prepare future military strength increase regarding military training results, and big data analysis has opened such possibility. We analyze the data from KCTC (Korea Combat Training Center) training to investigate the factors affected victory in offensive operations. In this context, we develop a way to measure the victory and the factors related to it from existing studies and military doctrines. We first identify Independent variables that affect offensive operations through variable selection and propose a mathematical model to explain combat victory by performing multiple regression analysis. We also verify our results with battalion-level live training data as well as previous studies on victory factors in the military doctrines.
The Challenge of Managing Customer Networks under Change : Proving the Complexity of the Inverse Dominating Set Problem
Chung, Yerim ; Park, Sunju ; Chung, Seungwha ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 131~140
DOI : 10.7737/JKORMS.2014.39.2.131
Customer networks go through constant changes. They may expand or shrink once they are formed. In dynamic environments, it is a critical corporate challenge to identify and manage influential customer groups in a cost effective way. In this context, we apply inverse optimization theory to suggest an efficient method to manage customer networks. In this paper, we assume that there exists a subset of nodes that might have a large effect on the network and that the network can be modified via some strategic actions. Rather than making efforts to find influential nodes whenever the network changes, we focus on a subset of selective nodes and perturb as little as possible the interaction between nodes in order to make the selected nodes influential in the given network. We define the following problem based on the inverse optimization. Given a graph and a prescribed node subset, the objective is to modify the structure of the given graph so that the fixed subset of nodes becomes a minimum dominating set in the modified graph and the cost for modification is minimum under a fixed norm. We call this problem the inverse dominating set problem and investigate its computational complexity.
How does Dependence on Portals Help Online Retailers` Growth? : The Moderating Effects of Firm Age and Niche Width Strategy
Park, Kyung Min ; Mun, Hee Jin ; Park, Sunju ; Chung, Seungwha ; Choi, Jeonghye ;
Journal of the Korean Operations Research and Management Science Society, volume 39, issue 2, 2014, Pages 141~154
DOI : 10.7737/JKORMS.2014.39.2.141
It is widely confirmed that online retailers can obtain crucial resources and greater growth potential by depending on the external web portal sites as it is explained in resource dependence theory. Nevertheless, recent studies show that the effect of dependence may not always be beneficial for firms and stress the importance of finding relevant contingent factors. In this study, we identify and suggest that firms` age and niche width strategy, whether generalist or specialist, are contributing factors on moderating the positive relationship between resource dependence and firm growth. To test our hypotheses based on the theory, we have collected monthly web traffic data of online retailers and portals from March 2000 and July 2008. The empirical results lend support to our theory of the firm age having a negative interaction effect on web traffic dependence. Moreover, results verified that positive effect of depending on the portals may become greater if the online retailer is a specialist in terms of niche width.