Abstract:A kind of viscoelastic spectral stochastic finite element method (VSSFEM) was developed and stochastic analysis of solid rocket motor grains was presented. Considering the randomness of solid propellant Poisson's ratio, viscoelastic spectral stochastic finite element formulations were derived from the incompressible or nearly incompressible viscoelastic incremental finite element method and orthogonal expansion theory. Finally, stochastic analysis of a hollow cylindrical grain with elastic restraint was presented. Analysis of examples indicates that this method is efficient and effective for stochastic analysis of viscoelastic body.

Abstract:The dimensionless equations of motion for mid-course of the boost-glide trajectory are presented and the trajectory optimization problems are solved with nonlinear programming method (NLP). Firstly, the maximum range trajectories with varied initial velocity, inclination of the velocity and maximum lift-to-drag ratio of the vehicle were generated. Then the minimal accumulated heating load and the maximum range trajectories with stagnation heating rate and load factor constraints were investigated. The numerical results of first kind trajectories show the influence of initial condition on the maximum range trajectories. The second kind of the optimal glide trajectory was compared with the pure ballistic trajectory under the same condition. The results show that the maximum heating rate of glide reentry declines while the heat load of the glide trajectory increases. Furthermore, the flight time of the glide is within the tolerance of the Thermo Protection System (TPS) of conical shape maneuver reentry vehicles.

Abstract:The equation for calculating Bladder dimension is derived based on the relationship between bladder pressure and the inner diameter of composite bearing cylinder. Effects of bladder pressure on the thickness, fiber volume fraction and bending properties of composite bearing cylinder were investigated. The composite bearing cylinder was manufactured by bladder-assisted resin transfer molding(BARTM) process. The experimental result shows that higher bladder pressure decreases thickness of composite bearing cylinder, increases fiber volume fraction and improves the bending properties. This indicates that composite bearing cylinder can be manufactured with precise inner diameter by BARTM process with a proper bladder pressure.

Abstract:3-amino-6-(3,5-dimethylpyrazol-1-yl)-S-tetrazine(ADMPT), 3-hydrazino -6-(3,5-dimethylpyrazol-1-yl)-S-tetrazine(HDMPT), 3,6-diamino-S-tetrazine(DATz), 3,6-dihydrazino-S-tetrazine(DHTz), 3,3'-azobis(6- amino-S-tetrazine) (DAAT) and some S-tetrazine high-nitrogen energetic compounds were synthesized. The structures of these compounds were represented and confirmed by IR, element analysis, 1H NMR and 13CNMR spectra. The thermal decomposition performance of DAAT and DHTz was investigated. Kinetic parameters of decomposition were obtained by DSC at different heating rates. The results show that DAAT is stable up to 283℃, with maxima exotherm at 330℃ and ΔH of 1974.33J/g. DHTz is stable up to 120℃, with maxima exotherm at 159℃ and ΔH of 1843.23J/g. The explosive power performance of DAAT and DHTz was calculated by VLW EOS.

Abstract:The air curing kinetics of PCS fiber was investigated by multi-curve integral method of thermogravimetric analysis. The PCS fiber was obtained by melt spinning of PCS which was synthesized at high temperature under high pressure. The results show that the apparent active energy of curing reaction of the PCS fiber is about 60～70 kJ/mol. The relationships between the mechanism functions and the curing temperature were studied. The results show that the air curing reaction of PCS fiber is controlled by the surface reaction of random nucleation and growth mechanism (n=3). According to the reaction mechanism, the apparent active energy of curing reaction of PCS fiber is also found to be about 60～70 kJ/mol. As a consequence, the exponential coefficient, A, is about 77.64.

Abstract:By orthogonal design strategy, PCS with a super high molecule weight was synthesized under high pressure from the PCS with a low/middle molecule weight synthesized under normal pressure. Its structure and performance were characterized by FTIR、GPC and NMR. It was found that suitable reaction condition should be 6 hours at 460℃ to 470℃ and under 1MPa to 2MPa beforehand. Average molecule weight of the synthesized PCS was 6400 to 8500. Both its degree of branching and its content of Si-H bond decreased slightly compared with the material PCS. The average molecule weight of PCS with a super high molecule weight could be adjusted preferably by means of controlling reaction time.

Abstract:The present paper deals with the long-time behavior of a non-autonomous evolution equations with quasi-periodic term. Firstly the existence of the inertial manifold with delay of the system was proved by transferring the non-autonomous system to an autonomous system through extending the phase plane. Then the approximate inertial manifold of the system was constructed.

Abstract:The multi-impulse rendezvous problem is a key research field of astronautics. Firstly, based on the operational research, this problem was converted to a multi-phase-multi- dimension dynamic programming question. Then the multi-phase-two-dimension dynamic programming problem was emphatically analyzed, and the state transfer equations and recursion equations of the performance function were deduced. The solution to the two-impulse and three-impulse problem and the validating examples were given later. ln the end, the dynamic programming idea which uses the evolution algorithm to reduce the dimension of the multi-dimension question was introduced.

Abstract:A time domain singularity extraction technique is presented to calculate singular integrals in time domain electric field integral equation solver. In singularity extraction procedure, the time-retardation effects in time domain integrals are included. Numerical examples demonstrate that the presented method can greatly increase the accuracy of calculation of the self-interaction and near-interaction impedance matrix elements.

Abstract:The MPSTD algorithm is applied to model compound slot coupler in the broad face of standard X-band rectangular waveguide. The slot resonant length and S parameters of the coupler are analyzed by MPSTD. The simulated results show that the MPSTD algorithm is accurate and efficient in the analysis of the waveguide coupling slot.

Abstract:A novel method for image enhancement, which exploits the properties of the double-density dual-tree DWT and the statistical characters of visual representation, is proposed. The double-density dual-tree DWT combines the characteristics and advantages of the double-density DWT and the complex dual-tree DWT. This allows the transform to provide approximate shift invariance and directional selectivity and is well suited for image enhancement. The algorithm corrects the global dynamic range (brightness) and adjusts local contrast in the new complex-directional wavelet transform domain. Comparisons with some popular image enhancement methods are made, showing the effectiveness of the proposed algorithm.

Abstract:Based on Litschitz infimum estimate and the technology of branch-bound, the global optimization algorithm for one-dimension finite wavelet filter approach is presented, Taking advantage of the peculiarity of this filter approach problem，the convergence rate of Lipschitz algorithm was improved from linear to second-order.

Abstract:A 3D statistical channels model for mobile frequency selective fading MIMO channels was proposed and a new joint space-time-frequency correlation function was derived. The 3D channels model integrates many known channel models and the new space-time-frequency correlation function takes into account such parameters of MIMO system as the Doppler spread, the 3D angle spread, and antenna array configuration. Furthermore, the impact of nonuniform angle spread and antenna array configuration on the Cross-correlation Performance of channels were analyzed based on the new correlation function.

Abstract:To analyze the transient scattering of homogeneous dielectric bodies, the Müller equations with MOT method were chosen. A singularity-extraction technique was presented to calculate the integrals of matrix elements, which considers the time delay effect. It could reduce the approximate value and improve the accuracy. The calculation specifies that the new method has lower-level errors in near singularity than the common method.

Abstract:A fast recognition and acquisition algorithm of the received signal of the satellite-based direct sequence spread spectrum/phase modulation(DS/PM) dual-mode transponder is put forward and the performance of the algorithm is analyzed. Compared with the traditional method, the algorithm improves the system performance, optimizes the system structure and reduces size of the hardware requirements by multiplexing the common processing unit(FFT/IFFT). The contradiction between the acquisition speed and detection performance with the high dynamic, low SNR and large Doppler shift is resolved. This research will be useful to the development of DS/PM dual-mode transponder.

Abstract:Auto-compensating the drift in optical gyros by IMU rotating mechanism is an important way to enhance the navigation precision. The theory of auto-compensating can be clarified in the navigation error propagating functions. Because the attributes of optical gyro determines that rotation of gyro will inevitably bring extra error, the rotaion of the whole IMU is the only mechanism, An eight-180-degree rotating mechanism of IMU was proposed and illustrated in detail. Analyses and simulation show that errors from long term drift can be highly restrained, thus navigation accuracy of both position and attitude can be greatly enhanced.

Abstract:A technical architecture for user preference model is presented, and the nature of the problem represented within a Markov Decision Process(MDP) combined with adaptive reinforcement learning algorithm is displayed. We provided a possible candidate solution for user modeling dynamically to satisfy the user's expected preference based on minimal or missing information. It is also a exploration for the evaluation of the user experience when selecting service providers. Simulations of the user models show that the MDP model is effective for learning the user preference with multi-state profiles.

Abstract:In the content-based retrieval, the conventional approach to the retrieval algorithms is to conduct the feature extraction and similarity match on the basis of single feature and then to conduct multi-feature extraction under the condition of weighting the result of single feature extraction. Such an approach incurs large amount of calculation and lacks flexibility. Therefore, a new architecture to organize different retrieval algorithms in content-based retrieval is proposed. It appears as a hierarchical architecture, which is able to acquire a gradually accurate result. The transfer factor, priority factor and complexity factor are defined in this architecture, which can help to combine different feature-oriented retrieval algorithms flexibly. Experiment shows that this architecture improves the retrieval efficiency, resulting in a reduction of 40% of the retrieval time.

Abstract:An information hiding technology is presented in this paper, in which the 3-D landform data is protected and the information of elevation is hidden in the texture. In keeping the terrain figure and hypsography, the terrain information is compressed in low bit ratio and least memory by using improved line-based code approach. A method to build the wavelet coefficient set which can be embedded into the hided information is provided. The strength of the embedding data is image-adaptive according to the wavelet quantization noise, achieving the maximum strength of Just Noticeable Distortion (JND) tolerance of Human Visual System (HVS). Since hiding process is accomplished by using Rijndael code to construct Hash one-way function, the proposed algorithm has very high safety and its arithmetic can be public.

Abstract:For the problem of semantic content sharing of information resources in P2P networks, this paper first proposes a multiple-ontology based resource metadata description framework, which divides resource metadata into core metadata and extensional metadata. Then, based on the metadata framework, this paper places emphasis upon the research of indexing strategy of resource metadata. A hybrid indexing architecture is provided. It uses community strategy to organize core metadata element and uses DHT and semantic association to index extensional metadata element, which combines local indexing and global indexing. Based on this indexing strategy, the work flow of resource discovery and the load balance strategy are designed. Compared with the related current systems, this indexing architecture will greatly improve the efficiency of resource discovery and the system's scalability.

Abstract:Random network for Lanchester combat, a novel theoretical model for combat is put forward based on the definition of random mapping. The model is an ER random sub-graph of directed bipartite graph, or a series of random mapping with the decreased size of mapping domains, in which the relationship of local interaction and the system behavior have been formally and explicitly represented. The results obtained mainly by simulation and analysis show that the efficiency of the whole combat network follows the Lanchester's square-law, and that the topological structure of the network generated by the model is heterogenous, following exponential-law of degree distribution. Finally, the influence from the factors of globe information on the efficiency of the whole warfare system is studied through data experiments for both “symmetric” and “asymmetric” combat cases. It ends up with a discussion on the significance of network modeling in the combat modeling theory, experiments and methods of calculation.

Abstract:It is only a tentative attempt to analyze motion trajectory data in the data mining style. This paper proposes an algorithm based on Apriori, a conventional data mining method, for mining frequent trajectory patterns of moving objects from surveillance video. Firstly, feature points are extracted for presenting continuous trajectories. Then a trajectory similarity measure is designed to obtain the frequency of trajectories. Finally, based on the values, Apriori algorithm is applied to automatic finding of interesting patterns in 2D object trajectories. Experiments on real life and man-made trajectory data set show the validity of the algorithm.

Abstract:k-NN query based on multi-autonomous spatial data source is widely used in spatial information realm. In this paper, incorporating existing k-NN query algorithm, a new k-NN query framework for multi-autonomous spatial data sources and its implement algorithm, is proposed. The experiment results show that the method performs well both in data transmission volume and corresponding time of the k-NN query system.

Abstract:The BOM-based simulation model component is the implementation of the description of BOM, which is regarded as the reusable interplay information package for rapidly building simulations or federation. With the introduction of XMI standard provided by MDA to interchange models, it is possible for the interchange of HLA simulation model components to be applied to different platforms, different programming languages and various domains on the two levels of simulation components modeling and implementation. So the reusability and interoperability of HLA can be expanded into other domains besides the distributed simulation domain.

Abstract:An algorithm named Lanet whereby the overlay network construction is based on the location information of underlying physical topology is presented. Each peer is connected to a small subset of the other peers which are close in the physical network. The peers that are close in the logical network are also close in the physical network. As a result, the expected delay of each hop in the routing path is very low. This leads to low latency stretch of the overlay network. This algorithm is scalable and distributing for a fixed subset of nodes act as landmarks is not required. Simulation results indicate that the latency of data location in these location-aware systems that are constructed with Lanet can be significantly decreased.

Abstract:The macroscopical properties and the changing of microscopical performances of artificial fog have been studied. In terms of the discussion of the forming theory of fog, the difference between experimental results and the theoretical calculation was compared. The results showed that the granularity and liquid water content of artificial fog droplet were a few less than that of the natural fog while the droplet concentration of artificial fog was higher than that of natural fog. Furthermore, the fog size distribution was different between them.

Abstract:By analyzing the auscultation flaws of traditional heart and respiratory sounds, especially the problem caused by the occurrence of SARS, a wireless heart sounds and respiratory sounds auscultation and monitoring system was proposed. The Bluetooth, data process and analyzing techniques were adopted. The mutual infections between the doctor and the patients were avoided and the system is useful for fulminating infections diseases.