In order to solve the problems of expensive and non-universal dedicated virtual situational teaching laboratory equipments, this paper proposed to apply Kinect to establish low-cost and strongly-immersive virtual situational teaching system. Figure image matting is a key issue of Kinect-based virtual situational teaching system. So a fast and real-time matting algorithm is hereby put forward with use of Kinect depth map. It adopt improved region growth algorithm to obtain trimap, coupled with the use of a set of shared sample points with low computational complexity. Through weighted filtering, image matting regions are smoothed so as to obtain accurate matting results. Practices in classroom situational teaching for Business English prove this matting method is robust and stable, and almost unaffected by light and complex background. Kinect-based virtual situation and somatosensory interactive technology can better meet the needs of classroom teaching, which is a low-cost and strongly-immersive virtual situational teaching solution.

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This paper analyzes the effect of stable behaviors when amplitude, phase of sine voltage compensation signal are added in the system, reveals that the dynamical behaviors mechanism that sine voltage compensation signal changes feedback voltage-mode controlled buck converter lies in changing the duty cycle without impacting the system stable error via analyzing the change of period multiplier in Monodromy matrix and conditions of period bifurcation, and finally achieves stabilization control for bifurcation and chaotic behaviors. The simulation and experimental results prove the correctness of the theoretical analysis.

In this paper, the authors carry out an introduction to the principles of implementing serial port communication by Android mobile and give a detailed explanation to this implementation process through a case. In other words, through .NET serial port communication realizing serial port communication between PC and control equipment, and then Android mobile delivers control signals to the PC serial port by way of Socket communications.