Applied Mechanics and Materials Vols. 347-350

Abstract: A relay selection criteria was proposed based on time division non-orthogonal cooperation, aiming at solving the problem of relay selection in the two-hop multi-relay cooperative communication to predigest the system design. The system BER (bit error rate) expression was obtained with its performance analysis under the condition of high SNR. Furthermore, computer simulations was conducted to show that the system diversity order is increased with the increase of the relay number under the condition of the distributed relay selection criterion, and diversity gain can be obtained significantly with the BER of the system significant decreasing.

Abstract: Distinctive dynamic traits of wireless self-organizing network make traditional layered protocol design method unsuitable, so a novel cross-layer protocol design and optimization method should be adopted. In this paper research backgrounds and motivations of cross-layer design method are introduced firstly. Then, cross-layer design policies, forms and methods are expatiated. On the basis of above explanations, a kind of general cross-layer architecture is proposed and analyzed. In the end, existent problems of cross-layer design method are pointed out.

Abstract: The space network is a new generation technology of satellites information transmission. It is a fully space based information system which owns the abilities including information automatic connection and retransmission, multiple nodes interconnection. The accessing resource plays an important role in the nodes interconnection. How to efficiently allocate the limited resource of links in space network is an important research subject in this area. This article proposes an improved genetic algorithm to solve the problem. The predictable orbit parameters of satellites are used to optimize the algorithm. The simulation results show that the algorithm achieves a higher user access rate and a lower link switching rate.

Abstract: A scheme of HARQ re-sending nodes selection for relay network is purposed in this paper. The study is focused on how to select relay node with minimum resending power under the particular required receiving performance of the destination node. The candidate relay nodes are divided into several regions according to the difference of resending power required. With this selection scheme, the diversity gain and high system power efficiency can all be achieved. The effectiveness of this scheme is proved by the simulation results.

Abstract: To improve the systems anti-jamming capability by making full use of distributing information of background signals spectrum for basis function (BF) of transform domain communication system (TDCS), a method of basis function design using M-ary sequence to express spectrum amplitude is proposed. The short-time spectrum characteristic of modulated and demodulated signal of single-chip waveform coded basis function is analysed with jamming coexistence. Then the analytic expression of system bit error rate (BER) is derived and the optimization problem of solving the BER analytic expression is converted into the problem of solving maximum signal-to-interference-plus noise ratio (SINR). The problem is solved by utilizing the uniform distribution characteristic of random phase. Then the M-ary basis function is obtained. The simulation result shows that the designed system has better anti-jamming capability than conventional binary basis function system, especially in the condition of high interference-to-signal ratio.

Abstract: A new video watermarking scheme against geometric distortions is proposed, which is most suitable for DCT-encoded compressed video, like MPEG-2, MPEG-4, H.264, etc. To lower the computational cost, 2-D DFT coefficients are constructed directly from the block DCTs by exploiting a fast inter-transformation. Then a watermark is embedded in a RST (rotation, scaling, and translation) invariant domain generated by performing the Fourier-Mellin transform (FMT) on the 2-D DFT magnitudes. For resisting different video format conversion, the watermark detection is performed in the spatial domain. The experimental results show that the proposed scheme is transparent and robust to typical signal processing attacks, lots of commonly geometric distortions including scaling, rotation and some combination of several attacks, and frame dropping.

Abstract: This paper discusses the neural network application for the information processing in the netted radar tracking systems compared with the problems of the conventional radar information processing. And then test the neural network using simulation method. The simulation result shows that the neural network method can perfectly solve the target tracking problems in the netted radar systems.

Abstract: Constructing virtual battlefield terrain is a very important subject in military simulation. In allusion to the shortcoming of actual triangulated irregular network, an adaptive triangular irregular network is proposed in this paper, and the 3D modeling of the battlefield terrain is built. Effectiveness and speediness of the proposed method was demonstrated by the experiment result, and the details and precision of terrain mode1 is better than others.

Abstract: This paper designs and realizes algorithm of symbol synchronization for LTE system. In order to validate the feasibility of symbol timing synchronization algorithm, a series of simulations are performed with LTE channel models and the simulation results are analyzed carefully. Simulation shows that this algorithm has a great advantage of system implementation. It can be found the symbol start position within the shortest time.

Abstract: Retracted paper: Accidents to pipelines have been recorded and they often result in catastrophic consequences for environment and society with a great deal of economic loss. Standard methods of evaluating pipeline risk have stressed index-based and conditional based data assessment processes. Data mining represents a shift from verification-driven data analysis approaches to discovery-driven methods in risk assessment.