Applied Mechanics and Materials Vols. 687-691

Abstract: Digital watermarking is a new information security technology, and it uses the information to protect the security of multimedia data hiding technique. Digital watermarking in wavelet domain can make effective use of the human visual system characteristics, and can be compatible with the international compression standard, and the embedding watermark signal energy can be distributed to all of the pixel space. Based on the characteristic of multi-resolution wavelet decomposition and human visual system model matching, digital watermarking algorithm based on wavelet transform is proposed in this paper. The algorithm for tamper proof is designed by quantifying the significant wavelet coefficients to embed watermark sequence. Preprocessing and quantifying the image of this algorithm are studied, which resolves the rounding error and overflow problem brought by the watermarked image pixel values of wavelet transform. Through various attack test and analysis, the experimentation shows that it has strong robustness, can resist many common image attacks, and has strong practicability.

Abstract: At present, with application scope enlargement of GPS, traditional positioning method can't meet the growing performance requirements more and more. So kalman filtering theory is applied to national defense and civil enterprise in satellite navigation and it has very important significance.

Abstract: The demand for automatic counting of pedestrians at event sites, buildings, or streets has been increased. Existing systems for counting pedestrians in video sequences have a problem that counting accuracy degrades when many pedestrians coexist and occlusion occurs frequently. In this paper, we introduce a method of clustering optical flows extracted from pedestrians in video frames to improve the counting accuracy. The proposed method counts the number of pedestrians by using pre-learned statistics, based on the strong correlation between the number of optical flow clusters and the actual number of pedestrians. Furthermore, we compare the performance of two algorithms that use Harris corner points and lattice points when optical flows are detected. We confirm that the counting accuracy using feature points is higher than that using lattice points especially when the number of occluded pedestrians increases.

Abstract: In the logistics system, the Internet of things information transmission problem is researched. The ZigBee, 3G technologies are fused in the radio frequency identification (RFID), a set of logistics networking platform is designed based on 3G-ZigBee, with the functions such as multipoint automatic identification, real-time positioning, wireless network and RFID. The logistics system is designed, the routing algorithm of logistics system is analyzed, the improved LEACH algorithm is proposed, the NS component is used for the simulation analysis. Through the simulation results, the best balance point between energy consumption and network density is obtained, the parameters of the logistics system are optimized. Finally, software design idea and workflow are presented, the purpose of the remote control is achieved.

Abstract: The final goal of cognitive radio system is to improve the usage of the idle spectrum resource, thus improves the capacity of the cognitive users. However, the capacity of the cognitive radio system is related with the probability of spectrum detection and the signal strength of the secondary users. Aiming at this problem, a cognitive-transmition model is proposed using continuous time Markov chain, and close form solutions of the probability of all states are given theoretically. Furthermore, the mutuality of system detection probability, signal to noise ratio of the cognitive system, capacity of the cognitive system and overall spectrum usage are analyzed synthetically. The analyze results are tested by numerical simulations.

Abstract: Dithering particle swarm optimization (DPSO) algorithm is introduced into adaptive polarization mode dispersion (PMD) compensation in optical communication system. The DPSO algorithm has the merits of rapid convergence to the global optimum, without being trapped in local sub-optima, and good robustness to noise. How to implement DPSO as a component of a control algorithm in adaptive polarization mode dispersion compensation is described. Performance comparisons between PSO and DPSO were carried out theoretically and experimentally.

Abstract: This paper will present a novel wide-band double-ridged standard horn antenna at 0.5~6GHz with the software named Ansoft HFSS, which is mainly used for far-field antenna measurement system. A simulation model of wide-band double-ridged horn antenna and the detailed design of each part of the structure will be given. With optimization in HFSS, the results show that the VSWR in the whole frequency band is below 2.4 and average gain larger than 6 dB. Finally, results of the measurement for VSWR, gain and radiation pattern are presented and discussed, which indicates that the built prototype is consistent with the design goals very well.

Abstract: A reconfigurable wideband Log-Periodic Dipole Array (LPDA) is here in introduced. Built utilizing low cost it can cover frequencies from 0.2GHz to 2GHz, through the discrete adjustment of its elements. The gain of antenna in a given frequency band of operation can also be changed by the reconfiguration of its elements. The design, construction and testing processes are discussed and a performance analysis is made based on computer simulations. In this paper simulation software HFSS is used to get the optimization design of LPDA, and the simulation results are agree with the experimental dates appropriately.

Abstract: This paper brief describes FIR anti-aliasing filters with equiripple pass bands and stop bands. We designed equiripple linear-phase FIR filters with one stage, two stages and three stages. The simulation results of the proposed design scheme are very encouraging as far as robustness and computational complexity are concerned

Abstract: This paper studies a variable rate optical Orthogonal Frequency Division Multiplexing Passive Optical Network (OFDM-PON) real-time access system model, using the signal processing method of oversampling. The basic principle of the model is that the access system uses different oversampling rates according to the allocated bandwidth to different Optical Network Units (ONUs), ensuring that the entire system can utilize the existing hardware conditions to maximum effect. The proposed system uses Xilinx V5 FPGA to generate real-time OFDM signals. MATLAB software is used to recover the signals and calculate the bit error rate (BER). The simulation results are presented and analyzed to verify the performance of the system.