Applied Mechanics and Materials Vols. 543-547

Abstract: Compressive sensing (CS) theory asserts that one can recover original signals from far fewer random samples under the condition of being sparse. CS theory is applied to high resolution imaging of vehicle-mounted stepped-frequency forward-looking ground-penetrating radar. This paper explores an approach of obtaining discrete scattering structure of the metal mine based on CS imaging and extracting geometry parameters to discriminate targets. Real data of vehicle-mounted stepped-frequency forward-looking ground-penetrating radar is processed. High resolution images of the metal mine with double-scattering structure are obtained. The feasibility of the method is tested through these images.

Abstract: A new method based on bi-spectrum for generating random driving signal in time domain is presented for multi shakers in random vibration test. Firstly, the equivalent relationship of amplitudes and phases between auto-spectrum and bi-spectrum are established, Secondly, MIMO linear system are supposed, relations between driving bi-spectrum and response bi-spectrum are set up, inverse operation are used for calculating the driving bi-spectrum, Finally, the equivalent relationship are obtained, random driving signal in time domain according with reference requests are got. A numerical example is done, the result show existence of the equivalents. At the same time, random vibration experiment about cantilever beam is made to prove the effective aspects of the method.

Abstract: Image vectorization plays an important role in the digital image processing. Because the traditional linear vectorization methods have some shortcomings including processing data slowly, being sensitive to noises and being easy to be distorted, this paper proposes an image vectorization method based on mathematical morphology. In the paper we present an improving immune genetic algorithm based on chaos theory. The over-spread character and randomness of chaos can be used to initialize population and improve the searching speed, and the initial value sensitivity of chaos can be used to enlarge the searching space. To avoid the local optimization, the algorithm renews population and enhances the diversity of population by using density calculation of immune theory and adjusting new chaos sequence.

Abstract: In order to improve efficient of compressed sensing image reconstruction, an improved gradient projection algorithm of compressed sensing theory is proposed. In improved Gradient Projection algorithm, the pursuit direction is updated by search at negative gradient direction, thus the gradient direction is a single direction, because the traditional gradient projection algorithm searching at alternating searching method ,the efficient of gradient projection algorithm is higher than the traditional gradient projection algorithm, Experiment results show that, compared with the GPSR algorithm, the IGPSR algorithm improves the signals reconstruction accuracy, improves PSNR of reconstruction signals, and exhibits higher robustness under different noise intensities.

Abstract: This paper presents an indoor positioning system based on RFID, which introduces electronic tag assisted positioning, according to the plurality of the electronic tags which are arranged in the target area as equilateral triangle, and the reader reads the information and Received Signal Strength Indication (RSSI) within its reading range. Sampling and calculation of the positioning result is controlled by the core circuit. Experimental results show that the indoor positioning system has excellent positioning accuracy, with high efficiency and low cost.

Abstract: The first challenging step of the demodulation of the Digital Video Broadcasting Second generation signal is frame synchronization. Physical Layer header is composed of Start of Frame and Physical Layer Signalling code. When the Start of Frame and the structure of Physical Layer Signalling code are known, Choi and Lee, Kim et al denote some Choi Lee Detectors and Post Detection Integration techniques, using the combination of differential detection of header code. In this paper, we present a scheme to achieve frame synchronization on the condition that the Physical Layer header code is uncertain.

Abstract: Based on the research of special new workstation system module, this paper focuses on the solution of key technologies such as high performance computer system integration, high resolution video frame extraction, multi-layer multiple analog video window fusion, independent video input source synchronous, large capacity and high density FPGA design. Using high-performance workstation main control module and video cards as the foundation, develop a variety of sensing information radar display module, a variety of types of high-resolution graphics/image frame extraction module in order to realize the seamless connection with high performance computer.

Abstract: Distributed wind power is a new form of wind power generation, which under a limited transmission grid resources condition can makes full use of small wind resource. Therefore, it has economic and practical value to develop distributed wind farm. However, the SCADA system of distributed wind farm is the basic safeguard to ensure distributed wind farm to be safe, reliable and economical operation. Compared to other SCADA system, the SCADA system of distributed wind farm has difficulties in data transmission and information integration. This paper puts forward information integration technology based on OPC XML and data transmission technology based on the combination of ZigBee and 3G wireless network to solve the above problems.

Abstract: With the development of intelligent vehicle technology, vehicle detection based on vision analysis has become an research hotspot in forward collision warning system development. Aiming to solve the existing problems in the current vehicle detection methods, for example, the detection accuracy is sensitive to the variation of illumination and object angle, we propose a forward moving vehicle detection method according to multiple vision clues fusion. Firstly, we locate the rough position using vehicle bottom shadow detection. The shadow is detected using an adaptive threshold image segmentation approach twice. Secondly, the symmetry of vehicle body and the perspective of camera field of view are both referenced to remove the inaccurate location in the first stage. The proposed method has been tested on several videos recorded in real urban conditions. Experimental results show that our method achieves 93.67% average detection accuracy in daytime, and its processing speed is more than 25fps. The proposed method has certain application prospects for improving the vision based forward collision warning system performance.

Abstract: An algorithm of best view based on occlusion points is proposed for current best vision algorithm. Occlusion area is found through analysis of triangulated depth images, mark diagram and occlusion points direction diagram are set up, and best view is determined according to numbers of occlusion points in mark diagram. Experiment result indicated that the algorithm is feasible and efficient.