Applied Mechanics and Materials Vols. 130-134

Abstract: A new image digital watermarking algorithm based on DWT is proposed, by which Arnold scrambling is firstly processed followed by wavelet decomposition in images. Then the watermark information is embedded in the processed digital images according to certain rules. The experimental results show that the algorithm has a better robustness against common attacks of JPEG and median filtering.

Abstract: Different behaviors of image information and noise in sparse decomposition were studied to identify the differences between image information and noise. According to the different coherences between image (or residual image), noise and over-complete dictionary, image information and noise are distinguished. One image adaptive filtering is realized by taking coherent ratio threshold as the constraints of extracting available information.

Abstract: High phase noise and low phase noise have been consideration in CO-OFDM systems, respectively. The hybrid mitigation algorithm is optimized to approach to high phase noise and low phase noise environment, and a hybrid half-blind phase noise compensation algorithm is proposed, which could be suitable to shifty DFB laser linewidth. 4QAM and 16QAM are used to modulate binary signal. The new proposed phase noise compensation algorithm is considered a mitigation method which has the ability of half-blind self-adaptation. It deduces the coefficient matrix in high and low phase noise compensation matrix and could improve performance under high or low modulation index situation.

Abstract: Aiming at the uplink multi-user STBC-MIMO system, we adopted the combination of the detection scheme about the linear MMSE interference suppression and symbol estimation, and the receiver maintained decoding simplicity. Theory analysis and simulation results reveal that the proposed scheme can suppress and cancel the interference from co-channel users effectively without increasing the complexity significantly.

Abstract: The Digital Signal Processors of TI C6000 series, have a structure called VLIW and a Harvard structure, and a electron system based on DSPs can meet the real-time requirement depending on making full use of the structures by its software. Therefore the executing efficiency of software will directly affect the real-time character of the whole system. In this article, several methods of software optimization for C6000 DSPs are summarized, including the use of intrinsics, data accessing band-width and software pipelining etc. Using these methods to optimize the C code software can mostly solve the bad real-time problems in processing and then the system can meet the real-time requirement.

Abstract: Reactive power compensation of distribution network is an important method to improve power quality and voltage stability, while reducing the power loss of the distribution network. In this paper the objective function is built to minimize all the costs which include power loss costs and investment of the dynamic reactive power compensation device divided into each year. The actual operation of the distribution network is simulated considering light, normal and heavy load operation conditions. Bacterial colony chemotaxis (BCC) algorithm is used to determine which nodes to install the compensation devices. The calculation of reactive power compensation is done with the back/forward sweep algorithm adapting to the radial distribution system. In order to compensate three different load conditions separately, the fixed part and the switching part of the dynamic reactive power compensation device are used. This method applies to 28-node system, the result demonstrates that the method is feasible and effective.

Abstract: This paper introduced the principle of DES encryption algorithm, designed and realized the DES encryption algorithm with verilog hardware description language, realized module simulation with Quartus II. Two comprehensive considerations from the resources and performance, one pipeline stage control is set in round function to improve the processing speed, Synchronous pipeline architecture of data XOR key round function and Key transformation function is realized on hardware to reducing logic complexity of the adjacent pipeline, round function multiplexing is realized by setting the round counter and controlling the data selector.

Abstract: Based on the principle of microwaves transmission, a novel method of tri-frequency ranging measurement is proposed. When the wavelength of the transmission signal is between 0.47m and 0.57m, the transmitter generates three signals that are co-prime in the wavelength and the interval of the neighboring wavelength is less than or equal to 0.01m. Tri-frequency method can achieve 50m-1000m unambiguous ranging detection. The maximum precision of measurement can reach 10^-6. The result is simulated by a program written in C language. In this way, the purpose of high-precision and long-distance measurement is realized.

Abstract: With the rapid development of networks and communications technology, the modern remote control technique has widely been used in many fields. By the Web technology, the local equipments can be connected with outside and enable monitoring the equipments in remote clients' space. At present many products adopt Embedded Chip to which an operating system is ported as a Web Server. This product has several advantages such as low power consumption, low cost, reduced size and better performance. This paper introduces a solution for embedded system access to Internet, through which we can remote access, monitor, and maintain conveniently. The solution which is based on Web and embedded technology adopts the way of human computer interface interaction to realize remote control to the equipment. The realization of this method for users provides a convenient, flexible and effective control method.

Abstract: The CO-OFDM single-mode optical fiber system is constructed by the Matlab coupled with the Optisystem. And the influence of different channel algorithm on the receiver of system is researched. The simulation results show that the system performance is improved by using LS or LMMSE channel algorithm. And the LMMSE channel algorithm can provide better performance than the LS channel algorithm. Compared with LS algorithm, the required receiver OSNR is reduced by about 1 dB using improved LMMSE algorithm at bit-error-rate (BER) =10^-4 in the CO-OFDM single-mode optical fiber system.