Abstract:Research on the ignition and combustion performance of kerosene in a direct-connected scramjet model was conducted. Successful ignition and sustain combustion were achieved in the supersonic combustor. The distribution of wall pressure was measured to validate the combustion performances under different conditions. The test results indicate that kerosene fuel can be self-ignited when the equivalent fuel-air ratio varies from 0.27 to 1.46. The strut and cavity structure are important for the ignition and stable supersonic combustion of kerosene in the model scramjet. When a little hydrogen was injected with kerosene, the ignition and combustion performance was greatly improved. Too thick strut, too high equivalent fuel/air ratio, too much kerosene injected into the first combustor can make the combustor choke, consequently, affect the work of the isolator and air-heater nozzle.

Abstract:The transitional flow over a complicated sphere-bicone figure was simulated by DSMC method. The isotherm and pressure contour were shown in the near-continuum region and the drag coefficient and the pressure coefficient distribution curves of the surface were also presented at different Knudsen numbers and different Mach numbers. Comparison analysis of the drag coefficient was carried out between simulated results and approximation data estimated by the bridging-function formula.

Abstract:Thermal Curing process was adopted to improve the traditional air-process to lower the oxygen content of continuous silican carbide fibers by leading oxygen as little as possible to the fibers during their curing treatment. The influence of the thermal curing process on the oxygen content of the fibers, the structure and properties of fibers were systematically studied by means of IR, EA (Element Analyse), SEM and XRD.

Abstract:The experimental data analysis, feature extraction, fault detection and diagnosis are focuses in recent rocket engine study. However, in practice, because of noises and the mixing of signals due to different components, the signal-to-noise ratio (SNR) is always low, so the signal analysis and the feature extraction are quite difficult. This results in the difficulty of fault detection and diagnosis. By applying independent component analysis (ICA) to the separation of source signals from mixed signals, high quality signals have been extracted for further studies. The example reveals this method is very effective.

Abstract:Fluctuating pressure provides an important basis for the analysis of structure response and for the study of the dynamics environment. A new technical approach is presented, by which numerical simulation of the mean fluid field is integrated with the engineering prediction model based on experiments. For the transonic rotated aircraft, the surface fluctuating pressure environment is analyzed and predicted. And the fluctuating pressure coefficient curves and the power spectral density curves are presented at different transonic Mach numbers and different angles. The results essentially accord with the experiment results.

Abstract:Rayleigh-Taylor instability of fluid interface was simulated by the smoothed particle Hydrodynamics(SPH) method. The growth of the interface instability was presented, and the fungus appearance of the instability was obtained. The characters showed by the numerical results indicate that the numerical results are logical, and the SPH method has the potential to simulate Rayleigh-Taylor instability.

Abstract:Selectivity estimation is crucial in a query optimizer for choosing a good execution plan for a given query. Selectivity estimates of spatial joins can be used as responses to the specialized user queries that seek approximate figures. Spatial join selectivity can also be used for evaluating the correlation between datasets. With the proof that mutually overlapped rectangles are sharing a common region which is also a rectangle, this paper gives a selectivity estimation technique for 3-way clique intersect joins. The efficiency of our algorithm has been validated by us using synthesized and real-world datasets.

Abstract:Many powerful parallelizing compiling techniques rely on the logic structures of arrays. However, in real applications, lots of arrays are flat one-dimensional arrays and hence may disable some compiling optimizations. This paper presents a new framework and algorithms for guessing the logical multi-dimensional array structures from the flat one-dimensional arrays automatically, and makes powerful compiling optimizations possible. We first give a lemma that points out the basic property which the guessed multi-dimensional arrays should satisfy, then based on this lemma we give two basic rules that should be followed in guessing logic structures of arrays, and finally based on the two rules we present the algorithms for guessing logic structures of arrays. The experimental results show the algorithms for guessing the logical multi-dimensional array structures are effective.

Abstract:After analyzing the research situation and the shortcoming of vulnerabilities database system, the distributed computing technology, database technology and Web technology are used to implement NSVADS. Based on Web, it realizes the access and maintaining tool to vulnerabilities database. The solution to vulnerabilities and patches download can be disposed easily, and the cost of system maintainability can be reduced. Patches pushed modular can realize long-range patches pull, vulnerabilities mend, and vulnerabilities detection.It can improve the system's automatical vulnerabilities mend, and provide helpful tool for disposing the network security vulnerabilities.

Abstract:The direction of the motion which blurs the image can be dealt with as unchanging during the short exposing time. If it is identified, the blurred direction can be rotated to the horizontal axis, and the image restoration can be worked out easily in one dimension. An excellent simple model for imagery statistics is that of a spatially isotropic first-order Markov process. The autocorrelation of the original image and its power spectrum are assumed to be approximately isotropic. The motion blurring decreases the original image's high frequency contents in the motion direction. Thus, a derivative of the image in the motion direction would suppress more image intensity than a derivation in other direction. Then the motion direction is identified from the blurred image. The derivation matrix is the key for the identification. We select a propriety unchanging step for the direction derivation, a 3×3 direction derivation matrix is then constructed by using the double line interposition. This 3×3 direction derivation matrix can help to identify any motion directions of the most motion blurred images with high precision. It is steady-going.

Abstract:We present a method to design symmetric orthogonal M-band wavelets with arbitrary regularity by using Grobner basis and syzygy module algorithm in computing algebra to orthogonalize the polyphase matrix. By using the existing methods, the computational process is complicated and the linear-phase can not be achieved. These drawbacks can be overcome by using the new one.

Abstract:Extraction of roads from the high-resolution SAR imagery is described. The method employs Hough Transform to identify roads, followed by a series of pre-processes. Gaussian probability iteration method instead of usually used CFAR detector or threshold segmentation is employed to identify the regions of interest. The generally used Hough Transform is replaced by the average Hough Transform. The peak values in the transform area are detected by a maximum search integrating global CFAR detector. Finally, a unique geometric constraint is used to discriminate the potential roads. High-resolution SAR images of MSTAR Redstone are used to illustrate our method, and the performance is satisfactory.

Abstract:This paper analyzes how the trajectory deviations in the airborne synthetic aperture radar (SAR) can affect the received data. It shows that the range error can be separated into space invariant and variant contributions, which can be compensated by the first-order and second-order motion compensation processing. To realize high resolution SAR image, this paper represents a motion compensation method integrated in range-doppler (RD) algorithm. Finally, the analysis and scheme are validated by the results on simulated data.

Abstract:We study the square-root algorithm for H^∞ filter by introducing the generalized square-root factorization for indefinite matrices. A method to calculate the hyperbolic transformations for triangularizing a given matrix, including the testing of its existence condition, is proposed. The H^∞ generalized square-root filter can thereby be algorithmically realized.

Abstract:The paper presents a newly defined pairwise geometric^［6～8］ invariant relationship of the line segments of the shape targets based on the formal work of this technology. The method recognizes the targets by comparing the multi-dimensional histograms which are formed by the newly defined invariant relationship. The experiments show that the new relationship is more accurate for regular shape recognition than the old methods.

Abstract:The observability problem of the passive location system utilizing the radial acceleration information of the emitter is analyzed. It is proved that the range and speed information of the emitter can be determined from the radial acceleration under certain conditions, so a new target motion analytical technology using bearing and radial acceleration measures is deduced. The observability conditions for this technology are analyzed and verified with the computer simulation.

Abstract:The principles of the particle filter and the representative-points of random distribution are introducedThe number-theoretic method in statistics is applied to the particle filter, The corresponding rep-points algorithms, which include the generation of initial particles, the sampling of the importance density and re-sampling, is given using the MSE rep-points. Then a deterministic particle filter algorithm, with the fewest random operative and unequally weighted particles, can be built. The simulation results show that not only the algorithm is feasible, but the performance and computational efficiency can be also improved to a certain extent.

Abstract:Based on the method of non-uniform grid-FDTD,a monolayer printed PLPDA was analysized.The influence of the single and double coated dielectric cover on the performance of the PLPDA was also discussed.Through electromagnetic simulation to the PLPDA, the standing-wave-ratio and directional-pattern of the antenna were got and the results were validated by experimentation.The analysis and experimental results fit perfectly.

Abstract:After studying the deficiency in C⁴ISR architecture development and research in the field, this paper puts forth the idea of C⁴ISR architecture engineering, i.e. applying the concepts, principles, techniques and methods of engineering to the development and maintenance of C⁴ISR architecture within cost and time constraints. We present the definition of C⁴ISR architecture engineering, and delineate the architecture life-cycle of C⁴ISR system.

Abstract:The BIT technique is an important approach to improve the testability and diagnostic capability of the system. But the high false alarm rate(FAR) is one of the important factors that prevent BIT from wider application. The states of a system are divided into 3 states that include OK state, intermittent state and faulty state. The Markov model is set up, the relation between 3-state model and 2-state model is compared. Theoretical analysis shows that BIT of 3-state model is better than that of 2-state model in reducing FAR as well as increasing false diagnosis rate(FDR).

Abstract:The basic principle and algorithm of the Principal Components Analysis (PCA) are introduced in detail. The debris recognition approach based on the PCA is presented, and the process of using this approach to deal with the debris recognition is described. The validity of the approach is proved and the satisfying effects on improving the veracity of recogniting and decreasing the workload of calculation are also demonstrated by the experiment of classifying a group of typical examples.

Abstract:On the condition of the underwater acoustic signal, the perturbed amplitude would be small, and the general hydrodynamic equation may be linearied. On the basis of this approximation, the horizontal dispersion relation and the form of the water surface are obtained. The results show that the water surface transversal mini-wave has the characteristics of shorter wavelength and lower velocity, therfore it can modulate the light indensity of the incident laser beam on the water surface， which lays the theoretical foundation for the detection of underwater signal.

Abstract:Based on the related knowledge of the functional disassemble in the engneering design. The feedback signal is thought to be classed as positive, zero, negative signal at the port of input by analyszing the working principles and its functional role model construction of feedback system. Then, the technology of the fault transmit analysis about feedback is put forth. The process of the fault analysis is illustrated by the fuel-metering system of the jet plane engine. The research results show this method can resolve a type of fault analysis of the feedback system effectively, and the range of applications of the functional role model is extended along with it.

Abstract:Transfer matrix method (TMM) is used to study the transmission properties of photonic crystals. The Mur absorbing boundary and periodic boundary are used respectively to truncate the computational region in photonic crystals. For two dimensional square lattice photonic crystals, the transmission coefficient versus the frequency of E-polarized incident electromagnetic waves propagating in photonic-band-gap structures is calculated in perfect periodic structures. A model of 2-D square lattice photonic crystals is designed and fabricated in microwave wavelength regions. The results of numerical simulation are in good agreement with experimental results. And also the properties of transmission are studied in 2-D loss, dispersive and absorbing materials of photonic crystals. And how the photonic band gaps are affected by loss and the dispersive absorbing materials of photonic crystals is investigated.