Abstract:One model of random media is presented according to the theory of spectral factorization in stochastic process and Hudson's model of cracked medium. The advantage of Hudson's model is to make contact between the crack's micro-parameters (crack number density) with the macro-properties (elastic constants) of cracked media. Using this advantage, we present an ellipsoidal random model. The results show that the model outline the relationship between micro-properties and the macro-properties of random media, and can flexibly and effectively describe real cracked media, and the crack number density has different effect on the elastic constants of random cracked media.

Abstract:Based on the distributed parellel computing platform with the LINUX+MPI parellel environment, a parellel numerical computing method with finite volume method(FVM), OC-TVD scheme, B-L turbulence model and domain decomposition method was developed to solve the 3-D compressible Reynolds-averaged N-S equations. This method was used to simulate the flow field of the hypersonic waverider shape vehicle. The numerical results indicate that the shock across the zone boundary is continuous and the parellel speedup ratio reachs 6.8 when 8 cpu is in using.

Abstract:The trajectory model and the mass model of SSTO reusable vehicle and the performance model of tripropellant liquid rocket engine are established. Optimal analysis whose objective is minimizing the vehicle gross mass is performed to attain the engine parameters. Results show that the performance of tripropellant engine is 10% higher than that of LH/LOX engine. This research is the basis of design and analysis of tripropellant propulsion system.

Abstract:The performance of the solid rocket ramjet and missile influence each other greatly. Integral system project design of missile propelled by unchoked solid rocket ramjet can bring the performance of the solid rocket ramjet and missile into play and make them work in harmony，and improve the performance of the missile and ramjet. Multimethod collaborative optimization algorithm based on genetic algorithm、Powell method and pattern searching method is used to find the best parameters of the system project of the missile propelled by the unchoked rocket ramjet. Using the optimized parameters, the missile can get better system performance.

Abstract:The theory of relative positioning and attitude determination using GPS was expounded in detail, then the model of positioning and attitude determination was constructed. The model errors was discussed in detail. An experimenal system was established to validate the algorithms. Finally several aspect of researching formation flying was put forward.

Abstract:During the development of the rocket engine, the new engine is coming from the fault analysis and the removal of its predecessors. In this paper, the concept of equivalent test data is presented. Then, using the Bayesian method, with a few field test examples, the reliability of new products are evaluated. With the result of the stage reliability evaluation, the reliability growth of the system can be evaluated. A sample is given to illustrate the method.

Abstract:Three-dimensional braided carbon fiber (3D-B CF) reinforced SiC composites were fabricated via infiltration and pyrolysis of polycarbosilane(PCS)/divinylbenzene (DVB). The results show that increasing pyrolysis heating rates can reduce cycle time of manufacturing. At the same time, it can increase the density of C_f/SiC materials and improve the interface between carbon fiber and SiC matrix. The flexural strength of C_f/SiC materials reachs 556.7MPa.

Abstract:In the paper, two common types of heat-treatment furnaces (vertical curing furnace and tunnel curing furnace) were studied as influence factors on the uniformity of polycarbosilane fibers. Results show that, the furnace structures have a great influence on the curing uniformity of PCS fibers, with a remarkably better uniformity of the tunnel furnace than that of the vertical furnace.

Abstract:The crosslinked products of polycarbosilane were heated between 200-400℃ before pyrolysis in order to investigate their effects on conversation of ceramic. It was shown that 73.9% ceramic yield was raised when heated two hours at 400℃.The dominating defects in structure of its product pyrolysed were pores,not cracks in structure of that without heat-treatment.The damage of fiber could be decreased significantly if such ceramic were used as base.

Abstract:This paper discusses how to develop adjoint model(ADM) and tangent linear model(TLM) of the parallel model based on shallow water equation.The parallel strategy of TLM is the same as the original parallel model.Parallel strategy of ADM is different.The three adopt uniform domain decomposition in order to improve the parallel efficiency.One domain decomposition is adopted on cluster parallel computer system.The computing cost of TLM is about as double as the original model and ADM's is about 3 times as that.The communication cost of ADM is about as double as the original parallel model.The speed-up of TLM is the best among three models.

Abstract:The observation of low-SNR moving targets has been a hot spot for a long time. A dynamic programming (DP) and track matching algorithm has been developed for the detection of subpixel-sized, low-SNR targets observed by mosaic imaging sensors. The primary advantages of this technique are its sensitivity to weak targets along with its robustness to target maneuvers and sensor instabilities. Enhancement is achieved by performing directional weight operation precede to DP and target data association. Experiments have been conducted and it is shown that low-SNR moving targets with maneuver and maximum speed of 1 pixel/frame can be detected with high probability.

Abstract:This paper puts forward a recognition method based on the parameter of the moving target that the missile-borne-pulsed Doppler radar can achieve and the HMM, and then analyzes the limited performance of the method under different circumstances.

Abstract:Mesoscale numerical weather prediction model is the efficient way to the weather forecast. MM5 model is the most popular mesoscale model in the world. It is necessary to implement by means of high performance distributed parallel computation because of the large amount of calculation. This paper analyzed the sequential algorithm, studied the implement of the parallel algorithm, discussed some improvements, and presented some results of the experiment of MM5 implemented on the distributed parallel computer.

Abstract:A dynamic network security model to solve the limitations of classic static network security model is proposed. This security model makes use of all kinds of security components to construct a five-layer defense architecture whose defensive ability can upgrade dynamically.

Abstract:IPSec is the only security technology that can be used pervasively in the Internet. Through analyzing the process of IPSec, we point out that network security processor is the key component to implement IPSec protocol efficiently. The architecture and application of the security processor state-of-arts are introduced in detail. Because the processing power of the network security processor of the shelf can not satisfy the requirement of the ports with OC-48 speed or higher,the analysis and forecast of the next generation network security processor architecture is given at the end of the paper.

Abstract:A general framework is presented for evaluating the availability on the network performances in a logistics network. The evaluation is based on mission-oriented rerouting strategies. As a representative,the availability on the traffic delay of some logistics flow is studied with different rerouting strategies and the graph on traffic delay is made. In the graph, the delays are analyzed by comparison.

Abstract:The paper applies the standing-traveling wave boundary condition to the PSTD method to replace the PML.In this boundary condition,electric or magnetic walls are placed around the domain to be calculated,and the reflection field is removed from the scattering incident wave.The formulation for the method in the condition of 2D is given. The method can save more memory and time than that of the PML when their results are compared. The numerical result shows that the new method is feasible.

Abstract:Photonic crystals have been extensively used in microwave and millimeter wave application,and that kind of photonic crystal whose structure is integrated into microstrip circuits have a good future.Microstrip structure periodically loaded with rectangular metal patches can be designed to be an excellent photonic crystal with a planar topology.Surface wave in certain frequency band will not be permitted to propagate.In this paper,Green's function plus method of moments is introduced to analyze this kind of photonic crystal.The propagation constant of surface wave for this microstrip structure is obtained by solving the characteristic equation.Proper parameters are chosen to get expected surface wave bandgap.This microstrip structure is valuable to microwave circuits and phased array antennas.

Abstract:Multicast can improve efficiently RTI's performance.We introduce general theories and implementation scheme of multicast assignment,display the multicast assignment strategy in KD-RTI, and discuss relevant problems in the process of using multicast, and give a resolution.

Abstract:The low speed maglev train which will be used in Badaling traveling line is regarded as the research object. On the basis of building the model of maglev control system and by analyzing the reciprocity between the maglev train and the rail, the designation of maglev train controller under the periodical irregularity of the rail is discussed. Two control schemes are also compared in this paper, one of which uses the relative displacement, the absolute velocity and the absolute acceleration as the feedback, the other uses the relative displacement, the relative velocity and the relative acceleration. The simulation results under different velocity and different bridge span are given in order to provide reference to the designation of the maglev control system and to the designation and construction of the rail track.

Abstract:Induction radio,different not only from the wire communication, but also from the wireless communication, will be widely used as a new communication mode in the field of the rail traffic and the military affairs in the future. The basal principle of the induction radio and the characteristics of the induction communication are emphasized. The ways of modulation and demodulation are analyzed. The circuit of the system is also provided. Based on the above analyses, and taking the current status of maglev in our country into account, solutions of communication at current stage is provided and the test results are put forward.

Abstract:The method which adopts FPGA chip to design for asynchronism latching accumulator of SINS is introduced. The accumulator's performance is analyzed and tested.

Abstract:The concept and description of the ownership management in the distributed collaboration system were proposed. The basic properties of objects /attributes ownership were summarized systematically. Then based on this knowledge, categories of the ownership management methods from different aspects were obtained. We discussed the limitation of HLA ownership management and improved the scheme. In our scheme, we proposed two new ownership management methods, provided the support to the object ownership management and solved the problem of atom attributes ownership management.

Abstract:A new method of measuring linearity of deep hole is put forward. Accordingly, the physical and mathematical model is established. Then the system error of measuring model function is analyzed. It is proved effective in practical application with the experiment of three-coordinated instrument.