Applied Mechanics and Materials Vols. 644-650

Abstract: This design is based on Visible Light Communication Technology, to achieve outdoor visible light communications and image recognition etc. through traffic lights. It will play a role on promoting the utilization of traffic lights. The system uses a LED dot matrix to imitate the traffic light, loading QR Code information on the LED dot matrix and then transporting it in a very high-speed flashing. In receiving terminal, first, webcam OV7670 collects information which from the LED dot matrix, then conveys the picture to FPGA, which is the processor. FPGA will handle the picture by gray scale processing, medium filtering and binary processing at last. Thus, the picture from the LED dot matrix will change to ‘0’ and ‘1’ in binary area. Secondly, as there’s a relationship between LED dot matrix and webcam pixels, we can count how many pixels represent one LED. Finally, we can decode the QR Code based on its own style, and display the final result on the TFT screen.

Abstract: As a new teaching assistance system, mobile network teaching system is built for those learners whose learning space position and time are irregular and self-learning requests increase. From the view of expanding the mobile function on the Moodle platform, this paper sets up a mobile network teaching system supporting different mobile devices access the system through wireless communication network, which meet teachers’ and students’ needs to get teaching resources conveniently, fast and efficiently and self-learn anytime, anywhere.

Abstract: This paper analyzes the new challenges that mobile management faces against to variety of access network coexistence and large number of mobile terminal access demanding in the future. According to the existing researches and the typical exemplification, this paper illuminates the definition and classification of location management. Based on this, a model framework of location management cost is proposed and it will have extremely vital significance for guiding 4G and the mobility management in the future. Finally, it points out the new challenges and new topic about mobility management in the future ubiquitous network and heterogeneous network environment.

Abstract: The echo signals of sky-wave over-the-horizon radar involve ionospheric phase contamination with spectrum expansion. The bragg peaks expand and cover the frequency spectrum of low speed target. So ionospheric phase decontamination is necessary before coherent integration. The traditional Hankel Rank Reduction (HRR) phase decontamination method constructs the Hankel matrix by folding the echo signal, estimating instantaneous frequency through singular value decomposition. But HRR method requires the prior information of signal components. The estimation is invalid without priori information. The algorithm presented in this paper does not require the priori information. The algorithm based on matched fourier transform can accurately estimate the phase contamination function for the clutter noise ratio is high. Simulation shows that the proposed algorithm has better performance in phase decontamination.

Abstract: Phased array satellite platform self-tracking system is for the stability between the missiles and other high-speed movement of the platform and the relay satellite two-way information transmission needs to carry out the self-tracking technology research of onboard platform-dimensional active phased array satellite. The system uses a sub-array correlation method for accurate measurement of the angle of the satellite signal. Receiving array is divided into four 4 * 4 sub-array, each antenna signal combining unit 4 sub array for 4-way A / D to be converted, through down-conversion, filtering, extraction and other processes to get a digital baseband signal, the baseband digital signal processing is to extract the angle error information into digital beam orientation system for tracking filtering operation, thereby ensuring that the transceiver has been aligned with the satellite antenna beam direction. In this paper ,phantom-bit technology for satellite tracking system under the condition of minimum beam displacement is researched for satellite tracking system.

Abstract: For the problem of presence fire district network, multi-station with one frequency fire emergency communication network based on TDD-OFDM is proposed. The network mode and the basic structure and operating principle of the receiving and sending equipment from central station, car relay stations, as well as single firefighter piggyback are introduced, as a result ,voice and video data can be high-speed transmitted, thus, the frequency utilization and bandwidth of the broadcast networks are improved.

Abstract: Based on jumping in ten digits, optimization of OSD module in FPGA storage and read. the Chinese character OSD information superimposed on the video, take a transparent overlay mode. OSD information is stored in the FPGA mostly, and communicates with the SRAM, through the OSD information into the SRAM, the program reads the character dot matrix information from the SRAM to improve the function of OSD and beautify the superposition effect.

Abstract: In classic radial sampling scheme, angle intervals between adjacent straight sampling lines are the same. And so the coherence between the sampling matrix and the sparse matrix is high. Many pseudo-shadows will occur on the reconstructed image. For this problem, we put forward a novel sampling scheme in which the scan lines are placed in the manner of golden section angle interval. In the resulting sampling matrix, the scan lines scatter randomly on the whole. Experimental results demonstrate that the algorithm proposed in this paper has lower correlation coefficient between sampling matrix and sparse matrix than classic radial sampling scheme and random radial sampling scheme. Image can be accurately reconstructed by collecting less data than the other two schemes.

Abstract: Total magnetic intensity (TMI) data is an important data for understanding the seafloor spreading of the South China Sea. In this paper, we studied to denoise the TMI data in the ocean subbasin of the SCS by using various filtering techniques. Based on the noise features occured in the data, we utilize the directional filter to reject noise of NS direction, and then apply the anisotropic diffusion filter to further elliminate the bead-like artifacts. The denoised result presents a well conherence of magnetic lineations in the ocean basin. The magnetic lineaments trend to nearly EW in the eastern subbasin while NE in southwestern subbasin. The intensity of the magnetic lineaments in the eastern subbasin is stronger than that in the southwestern subbasin.

Abstract: By the analysis of two filter smooth method principle on the platform of Oasis Montaj software,the author of the thesis selected one dimension nonlinear filter method to remove the noise signal of aeromagnetic vertical first-order derivative data, not only smoothing the contour but also enhancing the geological structure edge signal effectively.