Advanced Materials Research Vols. 433-440

Abstract: Wireless sensor network (WSN) is a emerging, highly integrated field which involves several subjects and colligate knowledge at present .It contains a large number ,even thousands of nodes concentrating with the monitor that controls wireless communications network systems .The nodes extensively distributed have facility of breaking down because of the diversified environment and exhausting of energy .For the limit of energy and communication capacity, this paper comes up with a new kind of technique that we import the multi-path transmission combined with network coding into WSN to balance network load, reduce energy consumption integrally and extend network life cycle.

Abstract: Based on the system hardware structure and the function of ARM system and the function of FPGA circuit, the realization of gray led controller is put forward. This way not only enables the developing work to be devided clearly, but also enhances the expansibility of the controller, sustains complex show, and makes the realization simply. This system has been realized and the effect is right. Keywords-component; formatting; style; styling; insert (key words)

Abstract: An image encryption algorithm by scrambling both the pixel location and the pixel value with sudoku grids matrix is proposed in this paper. As there is a certain mapping mode Between the Natural order and the numeric order in the row, line and block in sudoku grids, the proposed algorithm adopts the sudoku grids as secret key and scrambles the image according to the certain mapping mode. The algorithm is suitable for image with any size. The simulation experiments show that it has good encryption efficiency and perfect encryption effects. Also the transferring attack can be distributed equally by the algorithm which has high robustness, and good restoration result is produced.

Abstract: This paper proposes an intelligent video analysis technology for elevator cage abnormality detection in computer vision. By collecting, processing, and analyzing video images in real time, the feature vectors including the variation of foreground pixels, the variation of length and width of foreground region’s enclosing rectangle and the variation of foreground region’s center of mass are obtained. The background is modeled by the Codebook Subtraction algorithm，these feature data are processed via K-Means clustering to get observation sequences, which are used to model a Hidden Markov Model (HMMs) for the normal activity. Last, the abnormalities are identified by the difference, which is predetermined by observing the normal and abnormal activity testing sequences, from normal activity model

Abstract: We present a staggered-grid finite difference scheme for velocity-stress equations to simulate the elastic wave propagating in transversely isotropic media. Instead of the widely used temporally second-order difference scheme, a temporally fourth-order scheme is obtained in this paper. We approximate the third-order spatial derivatives with 2N-order difference rather than second-order or other fixed order difference as before. Thus, it could be possible to make a balanced accuracy of O (Δt4+Δx2N) with arbitrary N. Related issues such as stability criterion, numerical dispersion, source loading and boundary condition are also discussed in this paper. The numerical modeling result indicates that the scheme is reliable.

Abstract: This paper considers the optimal output tracking control problem for nonlinear systems affected by external disturbances based on stability degree constraint. The objective is to find an optimal output tracking controller, by which the cost function minimum and the state with the optimal having a higher mean-square convergence rate can be obtained. An optimal output tracking law is derived from a Riccati equation and Matrix equations. We give the existence and uniqueness conditions of the control law. Finally, a practical example is given to illustrate the effectiveness of the theory.

Abstract: In order to improve the real-time and flexible of FIR digital filter, a reconfigurable FIR filter system based on FPGA is designed. According to the filter specialties, the filter coefficients are calculated by the computer. And the configured coefficients of the multistage FIR filter are downloaded to the chip. The filtering computing is completed by the FPGA. The filtered data is transmitted to the computer through the USB2.0 interface for further processing, such as displaying, analyzing and storing. The states conversion between coefficients configuring mode and filtering mode is finished by FSM (Finite State Machine), which ensures the system to work orderly. The experimental results demonstrated that the coefficients configuring of the system is easy, which can adjust the filter coefficients flexibly according to the actual demand, and the filter is effective，that it can effectively filter out the noise signals.

Abstract: Pitch detection in noisy environment plays an important role in speech analyzing and recognition. In the light of the properties of Hilbert-Huang transform and the EMD soft-threshold de-noising method, an effective pitch detection method for noisy speech signal is proposed in this paper. Firstly, the EMD soft-threshold de-noising method is applied to realize the background noise reduction, secondly, using the Hilbert-Huang transform to detect the pitch period of the de-noising speech signal. The analysis proposed in this paper show that, compared with the conventional methods of the pitch detection of the noisy speech, especially for the low signal to noise ratio (SNR), this approach has a higher accuracy.

Abstract: This paper proposes a novel enhanced transmission line pilot impedance algorithm based on parameter identification, which is defined by the fault component sampling values of voltages and currents at both terminals of this line, and is used to distinguish the internal faults from the external faults. For the external fault, the magnitude of the computing inductance or resistance are greater than the determining data based on the series positive sequence inductance or resistance of the protected line, whereas they are smaller than the aforesaid setting values for the internal faults. The algorithm eliminates the inter-phase coupling caused by the unbalanced grounding fault, so it is the individual phase protection algorithm and possesses the high stability and reliability and immunes to the influence of load state and fault resistance. Performance analysis shows that the algorithm can be used various length lines through the line capacitances time domain compensation and may directly apply the line including the series compensating capacitors. Because the algorithm uses the short data window criterion, it has the short operating time and the little influence of transient components. It builds 1000kV 500km line model on EMTP, uses a laboratory model simulation data of a power system from Lan Zhou Dong to Xian Yang 750kV, executes the simulations under each fault. The simulation results indicate the fact that this algorithm can judge the aforesaid various fault state.

Abstract: Safety-critical software often includes some rarely executed critical operations that are often inadequately tested in statistical testing based reliability estimation. However, it is necessary to assess the reliability of safety-critical software to a high degree of confidence before it is deployed in the field. This paper discusses how to reduce safety-critical software statistical testing cost based on importance sampling technique. When both the critical operations and the entire software are adequately tested, the method can still compute the unbiased software reliability from the test results with much less test cases. Thus, the statistical testing cost of safety-critical software can be reduced effectively The simulated annealing algorithm for calculating optimum transition probabilities of the Markov chain usage model for reducing software statistical testing cost is also presented.