Applied Mechanics and Materials Vols. 644-650

Abstract: The Turbo coding ingeniously combine two simple component coders, use pseudo random interleaver parallelly to construct long code which obtains random characteristic , and take advantage of iterations between the two input/output (SISO)[1,2] decoder to realize pseudorandom decoding. This paper introduces encoding and decoding principle, design and simulation performance of Turbo codes. The simulation results prove that the design scheme is correct. From the spectral character we are acknowledged: not only can Turbo code effectively against the Gauss noise, but also has strong resistance to fading and interference properties. Based on our resuls, the Turbo code in modern communication has more advantages and will play more important role.

Abstract: In this paper, through the powerful visual programming tool called VC++ in the MFC library, used to achieve a function mapping system, its functions include drawing and linewidth graphics settings, select and text color for drawing. At the same time, a detailed implementation process of drawing system and function of the drawing system expansion, improves the system openness and practicality.

Abstract: Fetal electrocardiogram (FECG) is of great importance due to the potentially precise information that FECG carries could assist clinicians in making more appropriate and timely decisions during pregnancy and labor. In this paper, a method based on combined Stationary Wavelet Transform and Modulus-Maxima (SWT-MM) method is proposed for extracting the complete morphology of the FECG from maternal abdominal ECG (AECG). It particularly provides a different way of constructing the maternal ECG (MECG) template. The Efficacy of the method was validated using real data in Non-Invasive Fetal Electrocardiogram Database. The morphology of the extracted FECG was clearly seen that the fetal R-peak detection by simple differential-threshold method acquired the average accuracy of 96.8%. The method provides additional important benefits of fast speed and automated control for applying into the fetal monitors. Therefore, the method is potentially a strong tool for FECG extraction, especially in real-time use.

Abstract: For nodes’ self-localization in wireless sensor networks (WSN), a new localization algorithm called Sequence Localization algorithm based on 3D Voronoi diagram (SL3V) is proposed, which uses 3D Voronoi diagram to divide the localization space.It uses the polyhedron vertices as the virtual beacon nodes and constructs the rank sequence table of virtual beacon nodes. Then it computes Kendall coefficients of the ranks in the optimal rank sequence table and that of the unknown node. Finally, it realizes the weighted estimate of the unknown node by normalization processing Kendall coefficients. Simulation experiments prove that itcan obviously improve the localization accuracy compared with the traditional 2D sequence-based localization and can satisfy the need of localization for 3D space.

Abstract: Direct Digital Synthesizer （DDS） is a new theory starting from the conceptual phase required for the direct synthesis of waveforms, This system in the FPGA chip and D/A conversion circuit, filter circuit, amplitude amplification circuit and power amplifier circuit's support to achieve a meet scheduled targets multiple waveform output.

Abstract: In order to enhance the image contrast obtained in fog or haze, an optimized algorithm that based on the modified Retinex module is proposed. According to the defects of the traditional Retinex algorithm, such as high complexity and the halo phenomenon, this method enhanced the image global contrast by modifying the illumination component, and corrected the reflection component using nonlinear function. The experimental results showed that it can increase foggy image clearness quickly, adjust the image brightness effectively and overcome time-consuming drawback of original algorithm that greatly improve the efficiency and speed.

Abstract: This paper starts with the principle and operation approaches of Collocation orbit integration method, analyzing the integration process and initialization value of motion equation and variation equation. Through different integration lengths and polynomial degrees, this paper discussed the impact to orbit precision. It also compares the results to the scientific orbit which were offered by GFZ, through the analysis of this method; we also find the appropriate integration length and polynomial degree and validate the validity of this method.

Abstract: Presented to the π / 4 differential quaternary phase shift keying signal (π/4-DQPSK) using the discrete Fourier transform (DFT) for software demodulation algorithm in consideration of the actual received waveform into transition to π/4-DQPSK District and stable region, and only the waveform sampling point DFT transform the region stable recovery decision. simulation gives the demodulation method to achieve the same differential demodulation relatively simple structure, and the anti-noise in the signal to noise ratio greater than 3dB better performance than the differential demodulation performance, expected the algorithm is applied π/4-DQPSK software radio receiver design.

Abstract: Star tracker is an accurate autonomous attitude measurement equipment. Multi-channel star tracker has been widely used and the accuracy of multi-channel star tracker becomes an important issue to study. In order to study this issue, an error model of multi-channel star tracker is established and analysis of accuracy of multi-channel star tracker is carried out with the model. Simulation results show accuracy of multi-channel star tracker is much higher than the single channel ones. There is great potential to develop multi-channel star tracker in the future.

Abstract: To the question that traditional image inpainting methods depend on the structure characteristics of the image .The image inpainting method, on the basis of Bayesian compressive sensing, transforms the sparsity of the damaged image first, then gets the posterior distribution function of the sparse coefficient through Bayesian compressive sensing. At last, the mean and the variance of the distribution function are obtained. The mean can be used as the estimation of the sparse coefficient of the image, and the variance is the estimation of the noise. The emulation results proved that this method can improve the inpainting quality of images.