• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.4
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• pp.57-72
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• 2009

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.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1047-1052
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• 2011

Various services are created using mobile networks after mobile devices such as smart phones and tablet PCs are propagated rapidly. However, the contents of smart devices are not enough diversity because they depend on games and messaging services primarily. In this paper, we described the study have progressed based on mobile devices and networks using augmented reality technologies about virtual education system.

• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.68-73
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• 2008

Recently, remote observation and control technology has grown gradually. According to use home network system and expand super-highway information network, digital video technology observation system gradually has increased. In order that the user conveniently use better than to use web browser observation system, it uses existing digital observation system, personal digital assistant and control module in the place of internet.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1509-1514
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• 2013

In the distance education system existing, change of content by the content provider has not been performed in real time. But current car model is changed quickly. So it must modifying by contents provider in real-time. In this paper, we implement contents authoring system for modifying E-training contents easily. Especially, it use HTML5 technology. Through it, contents providers can modifying contents in various platforms easily.

• Solar Energy
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• v.19 no.2
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• pp.9-19
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• 1999

For determining solar benefit hour are two different methods required as a direct calculation which is more accurate but too slow, and a computer graphic protration which is less accurate but too fast. To have the later accurate, the hour to hour interpolation is used to provide less visual deviation. With directly pointing the solar location into the screen coordinate the waldram projection and stereographic projection which needs the number of fast algorithms to calculate the coordinates of the sun path and building configuration casting to the space are applied.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.501-506
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• 2001

In the procedure of the hydraulic control system analysis, a linearized approximate equation described by the first order term of Taylor's series has been widely used. Such a linearized equation is effective just near the operating point. In this study, the authors estimate computational errors in the process of applying the existing linearized equation stated above. For evaluating the computational accuracy in practical applications of the linearized equations, dynamic behaviors of hydraulic control systems are investigated through simulations with several kinds of representative hydraulic systems and the linearized equations suggested in this study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.517-523
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• 2003

This paper presents response property of the squeeze mode type mount using Magneto-Rheological fluid (MR fluid) . The MR mount for the isolation of multi-directional vibrations was constructed in this study. Both the mechanism and shape of the mount are the same as squeeze film dampers for a rotor system. In the present work, the performance of the mount was experimentally Investigated according to the magnetic field strength. The experimental results present that the MR mount can effectively reduce the vibration in a wide range of frequency by controlling the applied electromagnetic filed strength. Viscous damping and stiffness coefficients of the MR mount tend to be changed according to the variation of the applied currents In this study.

• Korean Management Science Review
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• v.26 no.2
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• pp.91-112
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• 2009

Recently, the green business/IT-related issues such as $CO_2$ emission and energy consumption have become spread out rapidly through the world. EU, the United States, Japan and other developed countries are using IT-related environmental regulations as trade barriers. Korea which has high rate of IT exports needs to establish systematic strategies to respond to these environmental regulations. However, it is not easy to find the related research about making green business/IT strategies. This research aims to deduce the green business/IT strategy framework and the suitable green business/IT strategies for the Korean situation. The green business/IT strategy framework is constructed from the analysis of preceding researches and those of the green business/IT strategies of Japan, the United States, and EU. The Korean green business/IT strategies are deduced from survey of experts using Delphi method. We expect that the results contribute to establish the systematic policy and action plan to reduce $CO_2$ emission and energy consumption of IT industry.

• Korean Journal of Veterinary Service
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• v.22 no.2
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• pp.151-158
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• 1999

This study was conducted to investigate the biochemical characteristics, the population and antibiotic susceptibility test of Clostridium perfringens isolated from intestinal contents of slaughter cattle in Kyung-ju and Po-hang. 1. In slaughter cattle Cl perfringens were isolated from intestinal contents of 51 of 101 cases(50.4%) and the population were $\leq$$10^5$cfu/ml of 44 cases(86.3%). 2. In antibiotic susceptibility test, ampicillin, bacitracin, cephalothin, penicillin polymyxin B were highly susceptible, ohloramphenicol, erythromycin, tetracycline were lowly susceptible, gentamicin, kanamycin, amikacin, streptomycin, sulfamethoxine, sulfamethazine were resistant. 3. In leaving test intestinal contents leaved for 0, 4, 8, 16, 32 hours in room temperature and population of Cl perfringens were gradually increased.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1996-1998
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• 1998

This paper deals with the tension control of continuous processing line for steel plant. In order to improve the tension control performance, tension control is included in POR. FF compensation is applied to get the same speed characteristics during acceleration and deceleration period. In simulation roll diameter variation and inertia variation are considered. It becomes clear that the proposed tension control system has high accuracy performance.