Abstract:The air ejector test facility was established to investigate the start performance of supersonic annular ejector. The investigation indicates that the higher the mach number in pipe, the higher start pressure and vacuum in cavity, and that the mixing room contraction ratio and the pipe configuration of the system deeply influence the start performance, but they have little influence on the vacuum in cavity.

Abstract:The dynamic problem of constrained layer damping (CLD) plate was investigated with the transfer function method in this paper. The equations of motion and the boundary conditions were derived by using the Hamilton principle. Then the unknown displacements were expressed in Fourier series. With the introduction of the state vector, the governing equation in state space was established by the distributed parameter transfer function method. The closed-form solutions of natural frequencies, loss factors and curves of frequency response of a simply supported CLD plate were obtained. Numerical predictions of this paper agreed very well with the results of NASTRAN.

Abstract:Based on the characteristics of launch window, an algorithm to calculate the launch window for space rescue mission was deduced. The problem of the launch window was divided into the plane window problem and the phase window problem. Analytical models of the two problems were established, and the analytical result of launch window was obtained. The launch windows of launch points with different latitudes in the same longitude were described with visualization curves, which served as the basis to calculate and analyze the launch window for space rescue mission.

Abstract:Cohesive cavities often occur in the solid missile motor grain. The strain field analysis of the cohesive cavity is an important problem to the evaluation of grain structural integrity. In this paper, a method to analyze the cohesive cavity's strain field is presented. With accelerated aging test, the variation law of the extensibility of propellant in the storage period was obtained. Using three-dimension viscoelastic finite element method, the Von Mises strain of the grain with cohesive cavities under internal pressure and axial acceleration loading was analyzed. In comparing the extensibility of propellant and the Von Mises strain of the grain in different storage period, the allowable maximum diameter of the cohesive cavity in different storage period was determined by the maximum Von Mises strain criterion. The analysis of a practical motor shows that the analytical method and these conclusions are available for using solid motor with cohesive cavities.

Abstract:A new method of landing position and attitude measurement of UAV using only one runway image, which is proved applicable to such circumstance as UAV approaching to the ground while the runway width is known, is proposed in this paper. Firstly, the relation between the attitude and the vanishing point of runway was analyzed. Then, the collinearity equation was transformed by the runway line and the image line equations coefficients. Furthermore, the position along runway and the bank angle was simplified on the basis of the reasonable assumption. In so doing, the landing position and attitude of UAV was calculated by previous relations. Simulate experiment results show that the new way is easy to realize and can satisfy the application requirement of autonomous landing.

Abstract:The estimation of system accuracy is an important part in designing the satellite navigation system and a major indicator in assigning the large-scale system as well. Thus, much attention should be paid to simulating, computing and analyzing characteristics of all the error sources and their influences on system accuracy in designing satellite navigation system. This paper induces the covariance estimating expression of system positioning accuracy by differentiating the measure equations and the set of theory and method for controlling the critical error sources, which apply to engineering, is provided.

Abstract:An innovative igniter based on catalytic decomposition of H₂O₂ was designed and manufcatured. With this igniter, an H₂O₂/HTPB hybrid rocket engine was tested. The experiment results demonstrate that this new igniter can successfully start the H₂O₂/HTPB hybrid rocket engine with 　combustion stability and good performance. The experiment results also show that the combustion efficiency will achieve the highest level when the hybrid ratio deviates from the best ratio of oxidizer.

Abstract:Newly-emerging high performance processors for intensive computing generally use distributed register files to support ALU array and to explore instruction level parallelism (ILP) by VLIW. Research of the VLIW compiler for distributed register file has been a hotspot. KernelC compiler ISCD developed by Stanford University was the first of its kind to deal with VLIW schedule for distributed register file and the only compiler actually applied as well. However, it limited the program for its weakness of scheduling the code with heavy workload. Based on ISCD, this paper presents a new VLIW schedule strategy. Experimental results show that it can deal with distributed register file allocation with heavy workload very well.

Abstract:A new programming model-the stream programming model is presented on the basis of the stream computing model. A new memory consistency model, named stream consistency for the stream programming model is proposed. In comparison with the traditional release consistency, the stream consistency is more relaxed. The requirements of the stream consistency for the program and system designs are discussed and a correct implementation is presented. The programmability and system overhead of the Stream Consistency is analyzed.

Abstract:A new channel estimator is proposed for Turbo receiver in MIMO-OFDM systems. The channel estimation error was taken into account in the evaluation of the extrinsic information for the coded bits. With the help of the candidates list of the list sphere decoder (LSD) and a prior information from the decoder, the approximation of the soft information in the conventional EM channel estimator was amended, and the statistic information of the soft symbols was improved for channel estimation. A new Bayesian EM channel estimation algorithm, which considers the autocorrelation of the soft symbols, was obtained. The simulation results show that the newly proposed algorithm has better performance in terms of both BER and mean square estimation error in comparison with the conventional EM algorithm.

Abstract:Based on the characteristic of GIS Web Service and dynamic Web Services Composition, this paper proposes the implementation mechanism of dynamic GIS Web Services Composition, which can effectively adapt to the dynamic characteristics of GIS Web Services and have vast data and CPU-intensive computing for the concept of Service Group(SG). According to the mechanism, the paper proposes the technical architecture of GIS Web Services composition, providing holistic framework and top-level guidance for studying dynamic GIS Web Services composition technology. Based on the results of workflow research, this paper puts forward Dynamic Service Composition Reference Model (DSCRM), which builds the framework for the development of dynamic services composition system and the development of dynamic services composition application. The ideas of this paper have been used in city emergency disposal project successfully.

Abstract:BPSK signal has been widely applied in new radar systems. The obtainment of Doppler frequency rate-of-change from BPSK coherent pulse signal is a key technology in the passive locating and tracking system of single observation. The influence of phase modulation is dismissed by square method and DFT (Discrete Fourier Transform) is used to realize the coherent integration between the pulses. This algorithm has small computation and high estimation precision of Doppler frequency rata-of-change. The computer simulation results show that the precision of parameter estimation meets the needs for passive locating and tracking system of single observer.

Abstract:The group delay of the Archimedean-spiral antenna was cataloged into the dispersion part and the constant part. Then a geometrical analysis was used to reveal the inherent dispersion property of the antenna's group delay. As a result, it effectively compensated the unknown antenna with its geometry measured. The constant group delay of the antenna was added into the system delay as a whole, and the whole delay was estimated through the Hough transformation of the hyperbola of a calibration marker (e.g. trihedral), as one of the curve parameters is the system delay. By an estimation of the azimuth location of the nadir of the curve using its symmetrical property, the dimension of the Hough transformation is further eliminated, so the method is efficient. Rail Ultra Wide Band SAR (UWB-SAR) data processing result verified the compensation method.

Abstract:In the sphere decoding (SD) algorithm, the strategy of initial radius selection and assignment has significant impact on the performance and complexity of the algorithm. In order to reduce the prohibitive complexity of conventional SD algorithm at low signal-to-noise ratios (SNRs), a novel strategy of initial radius selection and (quasi-) linear assignment is proposed based on V-BLAST signal model. The method of analyzing the performance and complexity of SD algorithm applying the proposed scheme is suitable for any nonuniform radius assignment strategy. Analysis and simulation show that, compared with the conventional SD algorithm, the complexity is reduced significantly by the proposed scheme at low SNRs, and the bit-error-rate performance is close to that of maximum likelihood detection in a relatively large SNR range.

Abstract:Area-ratio matrix, a new point-set distribution descriptor, is given in the paper, which is an invariance under affine transformation. Based on this, the paper reasoned out why the classic eigenvector approach (EA) matching algorithm has inferior anti-noise ability. To solve the problem, the paper proposesan algorithm of weighted eigenvector point matching algorithm based on area-ratio matrix (WEA-ARM). The algorithm enhances the EA's anti-noise ability, and can match point sets under not only the equilong transformation but also affine transformation. Experiments on both synthetic point sets and real images show the practicability of the algorithm and the correctness of the conclusions in the paper.

Abstract:A new framework for classifying human errors is presented on basis of the existing frameworks. The human error taxonomies derived from this framework are more comprehensive and consistent. In this framework, the seminal framework of “Commission/Omission” is branched out, and five basic human error types are derived. The five human error types can be used as primitives and combined with cognitive model in order to identify the human error modes at various cognitive modules. The process of human error identification is illustrated by an artificial example. The results show that this framework is effective.

Abstract:The application scopes of complex shape and structure units are becoming much wider. The problem is that these units are both complex in shapes and micro in structures. In order to mach complex form parts with high efficiency, the characteristics of fast tool servo process were analyzed in this paper, and a fast tool servo (FTS) system was developed, driven by voice coil motor. The characteristics of dynamics and electromagnetics were thoroughly analyzed, the transfer function model of FTS system was founded, and the control method was designed. On the basis of the above work, the performance of FTS system was tested. The result shows that the FTS system works with high resolution, good locating accuracy and high response, and it can act as fast feeding device of tool in fast tool servo process.

Abstract:A new seamless integrated navigation algorithm was proposed on the basis of ANFIS in order to enhance the performance of GPS/INS integrated navigation system during GPS outages. The algorithm adopted Kalman filter with pseudorange and pseudorange rate observations when the number of GPS satellites was not less 4. Otherwise, ANFIS was used to estimate the navigation errors and restrain the increasing INS errors. Experiments show that the new algorithm can improve the performance of integrated system effectively and enhance the horizontal position accuracy than traditional tight integration algorithms.

Abstract:How to perform the composability checking between models is one crucial issue in the composable simulation development. In light of this, the reference model of composability checking problem was proposed，then an approach to semantic representation of simulation models based on Hoare Logic was presented. As the compatibility and substitutability are the two flip sides of composability coin, the rules to check the compatibility and substitutability between semantics of simulation models were constructed, and the formal approach to semantic composability checking was established. Finally, the relations between the semantic compatibility and substitutability were analyzed.

Abstract:Accelerated life testing (ALT) of a product or material can obtain information quickly on its life or reliability information. Products or materials with operational period are often sampled and tested to evaluate their residual life. However, it is a main challenge how to deal with the operational period in statistical analysis for ALT application. The products are often treated as “new after operation” or “memoryless” and their operational period is ignored in residual-life evaluation on the assumption that their failure times follow exponential distribution. Since failure times of many mechatronic products follow Weibull distribution, the estimated precision of residual life of the products is low in the way mentioned above. This paper presents a novel approach based on equivalent time to statistically analyze ALT data of products or material with operational period. Estimated precision of the approach was studied by Monte Carlo simulation method. Results show that the approach can effectively estimate the residual life of the products and is more precise than that adopted previously.

Abstract:Diagnostic strategy design is an important task in the design for testability(DFT). In light of the fact that the practical tests are non-independency or costs of the texts are precedence-dependent, tests were considered to be distributed among multiple modes, and additional transition costs were considered if a test sequence involved mode changes. Then test costs and mode transition costs were combined to establish a heuristic evaluation function(HEF). Based on this HEF, a suboptimal diagnostic strategy searching algorithm was presented. Several cases were used to verify this method, and the experimental results show that this method efficiently solves the problem of diagnostic strategy generation with non-independent tests.

Abstract:The mechanism of opto-electrical stabilization is widely used in the field of observation and measurement of the armament. Its pointing accuracy relates the realization of function as target realization or tracking. As the important source of pointing error, the geometric error of the mechanism is inevitable. So the paper develops the model of pointing error using the method of multi-body system error's development, which adopts the azimuth-elevation mechanism as the example. The effects of error sources are also compared according to the statistical and sensitivity analysis. The research can be applied not only to the estimation of pointing error during designing, but also to the allocation and calibration of errors.

Abstract:Based on TMS320L F2407, a micro-computer control system used for an active heave compensation crane is designed. The working principle and function request of the control system is analyzed. The designing of the kernel of the DSP control system and the peripheral circuit were described in detail. The foreword channel, RS-224 serial man-machine interface, backward channel and the whole DSP control system software were designed, and the simulations were done with the MATLAB. The control system was implemented in a reduce-scaled prototype of the active heave compensation crane, and the test results show that the prototype works with a stable state of the active compensation character.

Abstract:Line segments are ordinary in man-made targets and matching line segments is the first step in a lot of fields, such as 3D reconstruction. Because of occlusion, the question of matching individual line segments is difficult to figure out with the traditional methods, and a novel approach based on epipolar-line constraint and the RANSAC algorithm is presented. Firstly, the points on line segments between image pairs are matched by epipolar-line constraint；Secondly, the RANSAC algorithm is used to estimate a straight line model fit to a set of 2D points, so the line segments of occlusion is matched availably. The result of the synthetic and real images is accurate and reliable.

Abstract:A transformation-competent artificial chromosome (TAC) library was constructed from the genomic DNA of orazy.mimuta. This library is composed of 5,000 clones while the average insertion fragment size is 45 kb. Stability test indicated that genome DNA of Orazy.mimuta was stably existence in the pYLTAC27 carrier. A probe was designed according to the sequences of cloned resistance gene. With the colony hybridization method, the genome library was screened. The result shows that resistance gene can be screened in this library.

Abstract:Three kinds of equivalent ciphers of AES are presented by separating S-box's affine transformation. Results from research showed that MixColumn matrix influenced the separation of S-box's affine transformation to a great extent. As a result, suggestions to the improvement of MixColumn algorithms were made.

Abstract:In 1966, Rosa conjectured that all trees are graceful, which has ever since been considered the famous Graceful Tree Conjecture (GTC). Now the conjecture still remains to be an open problem, and only a few kinds of trees are proved to be graceful. The number, however, can be enlarged by the approach presented in the paper. For any integer k∈｛0，1，2，…，n｝and 4k≠n，3n, there exists a bipartited labeling f of path P_n=v₀v₁…v_nsuch that f(v₀)=k . Based on this, a method for constructing bigger graceful trees by joining a path to a graceful tree is given and this makes much more trees to be graceful.