Abstract:A binocular visual relative positioning system based on CMOS vision camera chips is presented. The hardware structure of the system, selection of components and design of corresponding interface circuits are described. The hardware system includes: image collecting equipments, memories, a controller, a DSP and external interface circuits. An example is given. Being compact and highly integrated, the system has flexible interfaces, consumes low power and is of high precision. It can be easily installed in equipments, especially in embedded systems. So it have applications in many fields.

Abstract:Taking both computing and storage cost for query processing into consideration, we propose the multi-step implementation algorithm of distance-associated join indices (DJI) to efficiently support online spatial distance queries. The algorithm computes DJI in a stepwise strategy in which only a part of join indices is computed dynamically according to the user's query condition. Experiment shows that the proposed multi-step implementation algorithm of DJI has considerable performance advantage over the traditional methods.

Abstract:The design extraction from HDL description has been greatly needed in modern VLSI design process,such as the design verification，low power analysis，test generation and so on.This paper presents a new circuit extraction method using program slicing technique,and develops an elegant theoretical basis, based on program slicing, for circuit extraction from Verilog description. With the technique we can obtain a “chaining slice” for each given signal of interest.Our method has advantage in its fine grain,without writing-style limitation and in dealing with more Verilog components characteristics.The technique has been used in the design process and the results show its convenience，efficiency and good practicability.

Abstract:NIDSs deal with the problem of data reduction before analyzing the events. Two important measures used in ANIDS are proposed: FSS and new feature construction. A novel algorithm named SRRW is put forward first, which can produce OFS by recognizing all strongly relevant features and restrict them in searching process. A feature construction method is used to get the OFS. The correlations between the original features can be analyzed by factor loading matrix.

Abstract:Virtual studio is a new application of virtual reality in TV program production. Unlimited blue-box technique is the way to cover the scenery out of blue-box with an external chroma-key signal. It extends the movement of the camera in virtual studio. A universal unlimited blue-box technique is proposed based on the perspective projection. It can be applied to all kinds of blue-box structures and varied camera movements. The experiment result demonstrates that this technique is accurate and robust, and is sufficient to the requirements of virtual studio.

Abstract:Three-dimensional carbon fiber reinforced mullite composites (3D-B C_f/mullite) are fabricated via Al₂O₃ Sol-gel and polysiloxane infiltration-pyrolysis technology. The results show that nanometer γ-Al₂O₃ powders can be prepared through sol-gel using AlCl₃·6H₂O and (CH₂)₆N₄ as starting materials. Mullite can be synthesized by co-pyrolysis reaction between polysiloxane and sol-gel derived γ-Al₂O₃ at 1400℃ under N₂. The density, flexural strength, and fracture toughness of 3D-B C_f/mullite composites are 1.784g/cm₃, 282.5MPa and 17.7MPa·m^1/2, respectively. It is the large quantities of pores in composites that result in low density and flexural strength of 3D-B C_f/mullite composites.

Abstract:Low dielectric constant material which substitutes for conventional SiO₂ thin film as intermetal dielectric (IMD) is imperative for the reduction of interconnect resistance/capacitance(RC), cross talk and power consumption. SiO₂ aerogel film with unique properties such as ultra-low dielectric constant, low density and high thermal stability is one of the most possible candidates as IMD. SiO₂ aerogel films on a silicon wafer have been synthesized via a process of sol-gel, spin coating and supercritical drying. SiO₂ sol is prepared using a two-step procedure with acid/base as catalyst to investigate the effect of different amount of isopropanol(IPA) and NH₄OH on sol viscosity which is important for　spin coating and the microstructure of SiO₂ aerogel film. The optimized viscosity of SiO₂ sol is in the range of 9～15 mPa·s. It is found that the time of viscosity in 9～15 mPa·s becomes longer as IPA increases or NH₄OH decreases.

Abstract:Vanadium oxide thin films with nanostructure have been prepared on slide glass by sol-gel method. The resulting films are characterized by using scanning electron microscopy(SEM) and XRD. The influence of solvent and H₂O on the Sol-gel process is studied. And the effect of heat treatment condition on the valence of the films is also discussed.

Abstract:Currently there exist three multisensor measurement fusion methods, namely, augmented method, pseudo-sequential filtering method, and combined measurement filtering method. Accuracy of these algorithms are compared by a covariance analysis method, and a conclusion is drawn that they can all obtain LMMSE (Linear Minimum Mean-Square Error) estimation under some assumptions. Other performance of these algorithms, such as computation cost and flexibility, is compared by Monte-Carlo simulation. Results show that augmented method based on information filter has the lowest computation cost and highest flexibility, augmented method based Kalman filter and pseudo-sequential filter have higher computation cost, and the two combined measurement filters are less flexible because they demand that sensor measurement matrixes satisfy some additive conditions. These conclusions are valuable in practical engineering applications.

Abstract:Tatical data link system is an information system combining communications, navigation and identification, intended to exchange surveillance and command and control (C²) information among various C² platforms and weapons platforms to carry out varied missions of each service. Tatical data link terminals operate in the 960～1215 MHz band, which is reserved on a worldwide basis for the safe operation of aeronautical radionavigation equipment. The tatical data link system must be planned carefully before the operation. However several restrictions or limitations must be placed on operations. The typical constraints among different platforms are discussed in this paper. Then the tatical data link planning problems are modeled. Finally a greedy algorithm is described.

Abstract:Great capacity of operations and truncation error are the shortcomings of DCT in video codec recommendation H.263. An integer transform that is suitable for H.263 is designed based on lifting scheme, float-point DCT being replaced by integer DCT,and the measure of quantization being modified. The structure and performance are compared among integer transform、float-point DCT and fixed-point DCT,showing that integer transform is a nice transform with the advantage of perfect compression effect, free of float-point operations and fewer arithmetic operations.

Abstract:An analysis of time-domain scattering field has been given in soil with 2-D FDTD, and the numerical results are verified by comparing with the theory.The detecting of the underground pipe was simulated by using GPML absorbing boundary condition,numerical results of scattering of pipe are given in different sizes and different depths.

Abstract:It is crucial that how to accomplish dynamic weapon-target assignment (DWTA) efficiently to win the tank warfare. A model of DWTA in tank warfare is built and also a simple solution to it is proposed. The experiment results show that the solution is valid.

Abstract:A conceptual model of the command and control object (C²O) is described using the formal language LOTOS(Language of Temporal Ordering Specification), and the main properties of C²O and C²O-based systems are defined using ACTL(Action Based Temporal Logical). Then a model-based-verification approach is provided aiming at the above key properties verification. The practical example shows that the new approach is viable.

Abstract:The authors investigate the almost periodic solution of neutral functional equation with infinite delay of the following d/dt[x(t)-∫⁰_-∞q(s)x(t+s)ds］=A(t,x)x(t)+f(t,x_t) Some results on the existence and uniqueness of almost periodic solutions are obtained by use of C_h space, matrix measure and Krasnoselskii's fixed theorem. Especially, whenq(s)is zero matrix, we derive sufficient conditions for the existence of a unique and uniformly stable almost periodic solution, which generalizes several results in references［1～5］.

Abstract:SAR images generated on the basis of FFT suffer the poor resolution. In super-resolution algorithms of SAR/ISAR image the modern spectral estimation technique is usually used, such as Minimum Variance Method (MVM), AR model, eigen-vector, MUSIC and maximum entropy, to improve the resolution of the image. High-resolution spectral estimation of finite length sample is considered an underdetermined problem. In the framework of Bayesian criteria, a prior probability density function (pdf) of the spectra is included as a regular term in the cost function for MAP estimation. To improve the efficiency of calculation in 2-D case, fast algorithm is derived. The better resolution is achieved by the method while the method is applied to SAR image peak feature extraction.

Abstract:The finite-element method(FEM) is a popular technique for analyzing electromagnetic scattering, radiation, and penetration. Far-field radiation pattern of circular waveguide bevel cut and fields in the waveguide are analysed with three-dimensional FEM. Results of X band are compared with related documents and FEM follows the main beam very well but disagrees more with the measurements away from the main beam. The theoretical analysis shows that the main beam of far-field radiation pattern shifts from axis direction about 27°～42° and the gain is about 11～14dB with 30° the bevel cut angle in C-band, it can be applied to high power microwave.

Abstract:Virtual cathode oscillator (vircator) with electron beam (e-beam) modulated was studied using an improved “cellular conveyer” model and particle in cell (PIC) simulation. It is shown that the variation of the e-beam modulation parameters result in the change of vircator character, and microwave efficiency can be increased in proper e-beam modulation.

Abstract:An advanced Borris rotation method is proposed to solve the relativistic Lorentz equation. The method can describe the dynamic behavior of particles in intense magnetic field accurately. It is especially adaptive to simulate the interaction of ultra-intense laser and plasmas by using the advanced Borris rotation method in particle simulation.

Abstract:The combination of dynamic FEM and SPH method was applied to simulate the concrete target penetrated by high-velocity rigid projectile. The HJC constitutive model was applied to describe the behavior of concrete material. The numerical results are in good agreement with recent experimental results obtained from φ57 gas gun, and reproduce the details of the movement of projectile, the scattering of concrete, the propagation of stress wave in the target. The feasibility and validity of applying the newly obtained method and HJC concrete model to simulate such problems as the high-velocity impact and penetration in concrete have been also proved.

Abstract:This paper deals with the numerical simulation of stochastic resonance (SR) for detection weak signal. SR is a nonlinear phenomenon generally occurring in dynamical bistable systems excited by noisy periodic signals. Through SR, weak signals immerged in heavy noise can be amplified and optimized by assistance of noise, due to the interplay between noise sources and nonlinearity of the system. We present the numerical method to solve the bistable SR model based on Runge-Kutta algorithm, and propose a new kind of approach for detecting weak signal, which can effectively detect both period and aperiodic weak signals corrupted by the strong noise background.

Abstract:To get the optimal flight routes which satisfy constraints such as mission request, navigation and security in large scope and real terrain important to enhance the unmanned aerial vehicle (UAV)'s weapon system efficiency. An improved genetic algorithm which based on direct encoding method of individual and local optimization operator is represented to solve the route planning problem. By applying the complex constraints to the evolutionary process, the algorithm can overcome the drawbacks of canonical GA. The control parameters are selected by the uniform design of the experimental method, and the result of examples has proved that the algorithm is effective.

Abstract:The wind tunnel tests (in the case of suction plate and normal plate) and numerical simulations of longitudinal aerodynamic force of the 200km/h EMU's traction car are performed, and the longitudinal aerodynamic force coefficients are obtained respectively when the traction car is the front and rear one. The results show that, in the case of suction plate, the aerodynamic drag of the front car and the rear car increase evidently, and the negative lift of the front car increases while the positive lift of the rear decreased; the aerodynamic drag of the sub-floor contributes to the total drag by 25.9 percent. So to decrease drag the emphasis is the sub-floor.

Abstract:Based on the condition of constant distribution and const logarithmic standard deviation for Lognormal distribution, the Bayes method is used to analyse the accelerated factor of accelerated life test. Firstly, according to the complete life test data and the theory of distribution for function of the random variable, the prior distribution of accelerated factor is presented. Then, combined with a small amount of field type Ⅱ test data, the Bayes formula is used to calculate the accelerate factor. An example is given to illustrate this method.