• Journal of Information Technology Applications and Management
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• v.15 no.1
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• pp.243-260
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• 2008

To prevent low yields in the semiconductor industry is crucial to the success of that industry. However, to prevent low yields is difficult because of too many factors to affect yield variation and their complex relation in the semiconductor manufacturing process. This study presents a new efficient detection methodology for detecting abnormal yields including high and low yields, which can forecast the yield level of a production unit (namely a lot) based on yield-related feature variables' behaviors. In the methodology, we use C5.0 to identify the yield-related feature variables that are the combination of correlated process variables associated with yield, use SOM (Self-Organizing Map) neural networks to extract and classify significant patterns of past abnormal yield lots and finally use C5.0 to generate classification rules for detecting abnormal yield lot. We illustrate the effectiveness of our methodology using a semiconductor manufacturing company's field data.

• KDI Journal of Economic Policy
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• v.40 no.1
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• pp.1-30
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• 2018

Ongoing demographic changes have brought about a substantial shift in the size and age composition of the population, which are having a significant impact on the global economy. Despite potentially grave consequences, demographic changes usually do not take center stage in many macroeconomic policy discussions or debates. This paper illustrates how demographic variables move over time and analyzes how they influence macroeconomic variables such as economic growth, inflation, savings and investment, and fiscal balances, from an empirical perspective. Based on empirical findings-particularly regarding inflation-we discuss their implications on macroeconomic policies, including monetary policy. We also highlight the need to consider the interactions between population dynamics and macroeconomic variables in macroeconomic policy decisions.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1443-1450
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• 2015

Wastewater treatment plant(WWTP) has been recognized as a high energy consuming plant. Usually many WWTPs has been operated in the excessive operation conditions in order to maintain stable wastewater treatment. The energy required at WWTPs consists of various subparts such as pumping, aeration, and office maintenance. For management of energy comes from process operation, it can be useful to operators to provide some information about energy variations according to the adjustment of operational variables. In this study, multiple regression analysis was used to establish an energy estimation model. The independent variables for estimation energy were selected among operational variables. The $R^2$ value in the regression analysis appeared 0.68, and performance of the electric power prediction model had less than ${\pm}5%$ error.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.198-201
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• 2002

It has been well-blown that sandwich structures are efficient to resist bending loads by increasing the moment of inertia of the panel. However, the accurate theoretical prediction of failure load and its optimization of sandwich beams for strength under concentrated loads were so complicated. Moreover, the appropriate selection of the variables, such as face thickness, core density and core thickness of the sandwich beam with many theories has continuously researched to satisfy for the given strength to weight structural requirement. There will be interesting to investigate the effect of those variables with its optimization for the load resistance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.42-45
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• 2003

The purpose of this study is the development or the extensive Rapid Prototyping Technique. which can resolve the long-term manufacturing process, shrinkage and deformation occurring rapid prototyping technique. To begin with. the various specimens for tensile were manufactured on the basis of this modeling technology. Then, many kinds of the laminate pieces for the test were made by using the sheet metals lmm and 1.5mm thickness which is composed of the same ingredient. The tensile specimen were manufactured by changing the process variables, Such as electric current, pressure and resistance welding time for the Rapid Prototyping with metal sheet. And then by using the Taguchi method. The interrelation between the specimen and mechanical properties were determined and the system for the optimum process variable organized.

• International Commerce and Information Review
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• v.10 no.2
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• pp.433-453
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• 2008

Customer satisfaction and loyalty are becoming an increasing salient topic in many firms and in academic research. This study places significance in establishing corporate marketing strategy via analyzing and understanding purchasing by Korean and Chinese customer, especially those for service store, who serve as the core in marketing activities. To objectives of this study are to investigate which antecedent variables have significant effects on consumer perceived satisfaction or loyalty and to examine whether these factors have differences between Korean and Chinese customer. To test the hypotheses, such antecedent variables as the product quality, service quality, store reputation, store image. All variables are significant factors in both Korean and Chinese customer. Under the current increasingly rapid competitive market, product/service quality, store reputation/image can provide customer satisfaction and loyalty, can generate continual customer expansion of current customer through the reuse intention and can contribute to the expansion of new customers.

• Journal of Distribution Research
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• v.4 no.1
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• pp.1-16
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• 1999

Although many studies have emphasized the importance of a saleperson's effort in the area of service marketing, no one has studied the variables which may influence, or may be influenced by salesperson's effort by customers. This study investigates the effects of percieved salesperson's effort on some performance variables and the effects of some selected variables on perceived salesperson's effort. Two sets of data were collected - one on the service of beauty hair shops and the other on that in fast food restaurants. The results indicate that empathy of employees is positively related to perceived effort, and perceived effort has the positive effects on satisfaction, trust, and long term relationship. However, the relationships between store image and perceived effort, and that between trust and long term relationship are only partly supported and the effects of perceived effort on long term relationship are not supported in our empirical tests.

• Korean Management Science Review
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• v.11 no.1
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• pp.165-186
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• 1994

The increasing importance of end-user computing(EUC) is reflected in the proliferation of academic and practitioner literature on the subject. However, much of this literature assumes widely differing dimensions of EUC, which tends to make many researchers suggest different success factors for managing EUC. Moreover, the variables regarding EUC management have been considerably restricted in previous research. In order to overcome these problems, this study focuses on identifying EUC dimensions theoretically and deriving generic variables representing the mode of EUC management by factor analysis first. Then, based on these EUC dimensions and generic variables for EUC management, effective ways of managing EUC are hypothesized and tested empirically through a mail survey of end-users in 83 Korean business organizations. The results suggest that effective management of EUC should be different depending upon which dimension more importance is attached to in implementing EUC.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.338-341
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• 2004

The dimension of forged part is different with the die dimension by the various effects, such as, elastic deformation and thermal effect. And, the difference amounts are not same according to the forging conditions, for example, forging mode, flow stress, etc. Therefore, the use of FEA is effective to predict and update the required die dimension. However, the variables for FE simulation are also as many as variables in the experiment. The variables give very much effect to the accuracy of FE results. At first, the material model is very deeply affected to the estimated dimension of forged part. And the considering of loading and ejecting stages is also important to increase the dimensional accuracy. The experiment and FEA are performed to investigate the dimensional changes and accuracy in cold forging. Two types of upsetting are used to survey the effects of forging mode and stages.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.64-72
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• 1991

This paper deals with the state estimator and controller. All state variables' feedback in the system were used to improve electro hydraulic servo sysem were used to improve electro hydraulic servo system's responese charact- eristics. Many gains of the state variables'and estimator's are produced by the algebraic Riccati equation, and every state variables'optimal gain and estimator gain is selected by trial and error method. For the designed estimator performance's examination, this paper simulate the time response for the step input, the reduced velocity output in subjected to load torque, and the time response for the step input in changing the inertiamoment.