This paper proposed a de-trend method for vibration signal of telemetry based on the empirical mode decomposition (EMD) by correlation coefficient matrix. The signal is decomposed to a series of intrinsic mode component and the remainder item by EMD. It mainly distinguishes between the remainder item and the signal trend, according to the correlation coefficient matrix to determine whether some intrinsic mode component belongs to the trend item or not. The results show that signal trends can be extracted accurately through the effective combination EMD with correlation coefficient matrix and the proposed method has good applicability for different signals and different trends.
A surface position location means based on encode recognition is presented; the design of a new kind of absolute position optical mouse using this technology is completed. The position encode algorithm and the code recognition method based on image acquisition and image process are presented also. The structure of pen-type sensor system and light path design of it are discussed. The coordinate conversation algorithm and the detected technology of pen down and pen up are provided. The advantages of the new kind of mouse are that it can write and draw more easily than traditional mouse.
It is well known that if for a nonlinear system the parameterphas a small change, the multiple non-semi-simple defective eigenvalue can be separated into close eigenvalues, which is known as the near defective eigenvalue. For such a case, although the close eigenvalues are distinct, the system still has bifurcation property in natural. This paper presents the response analysis method at the near critical point of Hopf bifurcation in nonlinear systems. A numerical example is given to illustrate the application of the proposed method.
In this paper, we perform a 3D finite element analysis for the longitudinal settlement of a shield tunnel in soft soil, where a substratum soil contains a soft layer. The Mohr-Coulomb model is used for the substratum soil and soft layer. The longitudinal settlements are calculated for different elastic modulus and longitudinal length of the soft layer. The results show that a softer and longer layer will result in the larger settlement. It is also found that the maximum of the longitudinal settlements is linear function of the elastic modulus of the soft layer.
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