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As the generalization of using computer and the internet, most people, who would decide the acceptance of new information technology (IT), may consider the current systems which have been used so far. The objective of this study was to analyze the relationships between technology acceptance model (TAM) and the switching costs which may incur during switching from the current system into another on. For this purpose, this study suggested the hypotheses, in which continuity cost and setup cost, two types of switching costs in IT adoption, would influence perceived usefulness and perceived ease of use respectively. Moreover, the moderation effects of system types, hedonic system and utilitarian system, on the relationships between switching costs and TAM, were also suggested as the hypotheses.In order to prove the validity of the hypotheses, two groups were surveyed. Before surveying, to the one group who were believed to be a user of 'Cyworld', a new blog service, Naver Blog, was introduced. Similarly, to another group, Google Docs was introduced. The analysis by Partial Least Square (PLS) approach showed that most hypotheses in this study were statistically supported.

As concern about limited energy is gradually growing and wind energy is regarded as one of the best solutions, research on the wind turbine system has been vigorously accomplished. The commercial tools to simulate the non-linear dynamic characteristics of the wind turbine system are various, but the tools take a significant amount of time to simulate the control algorithm and require many input variables. In this paper, the procedures to simulate and examine the controller of wind turbines at the initial design stage are proposed by a 4 degrees of freedom mathematical model of wind turbine, and methodology to make the turbine model is also proposed by effective mass and stiffness defined in the modal domain. The proposed method in this paper is simpler than other methods. The simulations by the three kinds of models for the 2-MW wind turbine are accomplished to discuss the simulation results: a 2 degrees of freedom wind turbine model without considering tower and blade behavior, a 4 degrees of freedom model considering tower and blade behavior modeled by mode shape function, and a 4 degrees of freedom model by the suggested method.

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