Abstract:Taking symmetric full Navier-Stokes equations as governing equations, using two temperature and 11 species reacting air model, the hypersonic thermochemical nonequilibrium flow is simulated numerically. Then by using the "line-by-line" radiation model to compute radiation characteristics for the flowfield, the emission and absorption coefficients for 40000 wavelength points in 0.15～2μm are calculated. The radiation spectrum of air mixtrue and the main radiation specie NO in high enthalpy wind tunnel experiments is obtained. The calculation results indicate that vibration temperature exerts important effects on radiation.

Abstract:The nonlinear combustion instability process in liquid rocket engine is simulated. The gas controlling Navier-Stokes equations are described under the Euler coordinate.The liquid phase controlling equations are described under the Lagrangian coordinate.The two phase influences of gas and liquid are through the sources of equations.The sequential and parallel codes are written,and the codes are tested in parallel virtual machine environment.The results show that the parallel computation efficiency is reeasonably high.

Abstract:The operating characteristics of the solid ducted rocket are numerically studied.The results show that the performance of the unchoked ducted rocket (UDR)is superior to that of choked one.The unchoked ducted rocket should work with the high burning-rate-exponent fuel-rich propellant.The aluminum-magnesium fuel-rich propellants for the unchoked ducted rocket with high burning rate,exponent and good flammability limits are developed.Through the connected-pipe tests and numerical analysis,the performance of the unchoked ducted rocket engine is investigated.

Abstract:By introducing multiobjective handling mechanism of nondominated sorting and crowding, ability of distributed coevolutionary multidisciplinary design optimization algorithm is extended to multiobjective multidisciplinary design optimization (MDO) problems. The multiobjective distributed coevolutionary MDO approach maintains sufficient disciplinary autonomy, exploits synergism of disciplinary concurrent design optimizations, meanwhile it obtains a set of well distributed Pareto optimal solutions and makes a good approximation of the whole Pareto optimal front in one single run. It is applied to a missile design optimization problem with two system objectives and three disciplines－aerodynamic, engine, and control. Comparison with the results of the constraint method indicates that the multiobjective coevolutionary MDO approach can effectively approximate Pareto optimal front of the ploblem, providing plenty of information for design decision making.

Abstract:This paper describes the research on the pseudorange positioning of Autonomous Formation Flyer (AFF) of two satellites using pseudolites onboard, which is proposed by the NASA's Space Technology (ST-3). We build model and resolve relative position and time bias between satellites using Cartesian coordinate. The solution error covariance is very grave and unstable because observation geometry is very weak. In order to resolve this problem, we change Cartesian coordinate into sphere coordinate. It can be found that in the sphere coordinate system the solution error covariance is stable and can be used for simulation/covariance analysis.

Abstract:The transitional fluid flow in a two-dimension groove is simulated by DSMC method. The velocity vector and isotherm are shown at different Knudsen numbers、different span-chord ratios and different temperature wall. The limitation of the DSMC method in simulating the all-velocity flow field is also discussed.

Abstract:γ-Al₂O₃nanopowder whose specific surface area and average particle diameter is 189.6m²/g and about 9nm, respectively, is synthesized via sol-gel process using AlCl₃?6H₂O and (CH₂)₆N₄ as starting materials. Active Al₂O₃-SiO₂ composite powder is synthesized via diphasic sol-gel process using SiO₂and Al₂O₃ sol. After having been calcined at 1300℃ for an hour, Al₂O₃-SiO₂ composite powders transforms to mullite.

Abstract:Reliability enhancement testing (RET) and accelerated life testing (ALT) are the focus of attention in reliability testing research at present. The basic concepts about RET and ALT are discussed at first. The state-of-the-art in the research concerned is then briefly reviewed. The possible directions for further research in RET and ALT are summarized in the end.

Abstract:Data redistribution is necessary to enhance the algorithm performance in many parallel programs.Since data redistribution is performed at run-time,the cost of redistributing data among processors affects the performance of algorithm.High performance data redistribution is important for the parallel program.Butterfly algorithm for data redistribution of parallel computing is put forward in the paper.We have proved the correctness of the algorithm.Structured data transposition is designed.The performance is analyzed both theoretically and numerically.

Abstract:Some special tasks demand more than one object to be optimized at the same time in the communication network.To satisfy the demand, an interactive QoS routing algorithm based on multi-object decision-making is studied A multi-object nonlinear integer programming model is established which minimizes the delay and loss rate constrained by the bandwidth. According to the character of the model, an interactive algorithm for solving the model is presented. The upper bounds of the objective functions considered are modified in each iteration step to adapt to the decision-maker's information and network needs currently, which compress the solution space. An example demonstrates the interactive algorithm is feasible.

Abstract:Based on investigating immunological principles, the paper presents a multi-agent system for intrusion detection and response in networked computers. The immunity-based agents roam around the nodes, and monitor the situation in the network. These agents can mutually recognize each other's activities, coordinate in a hierarchical fashion, and take appropriate actions according to the underlying security policies. Mobile agents can learn and adapt to the environment dynamically and can detect both known and unknown intrusions. The multi-agent detection system can simultaneously monitor networked computer's activities at different levels, including the user level, system level, process level and packet level. The immunity-based multi-agent intrusion detection system is designed to be flexible, extendible, and adaptable that it can perform real-time monitoring in accordance with the needs and preferences of administrators.

Abstract:In the distributed simulation system, lots of redundant data flowing on the net seriously restricts the system scalability. The relevance filtering base on even-grid reduces the redundant data while it is inaccurate in region matching. Because the sizes of all cells in even-grid are identical, it is difficult to fit all entities in the simulation. A relevance filtering method based on a multi-level grid is put forward which overcomes the above shortcomings and is characterized by agility and speediness.

Abstract:In order to meet the need of the embedded application specific microprocessors development and overcome some disadvantages of current microprocessor simulation tools, a new embedded microprocessor simulation tool — VCPU is introduced in the paper. Being different from other microprocessor simulation tools, VCPU is a flexible full-featured multi-level virtual prototyping. The designer can use VCPU to verify the embedded system, both hardware and software in the early design stage. Errors can be found and corrected before fabrication， thus the design cycle is reduced. VCPU has been used in embedded microprocessor development successfully.

Abstract:Considering the problem of the maneuvering target tracking in the nonlinear system, this paper first proposes a modified algorithm based on “current" statistical model. Then a converted measurement Kalman filter is applied to tracking the target. Simulation results show that the algorithm improves the tracking performance obviously for the poor-maneuver or non-maneuver target, meanwhile it retains high tracking performance for the strong-maneuvering target.

Abstract:In the image recognition,the object's area is a very important characteristic. In this paper, a new and easy realized algorithm for calculating the area is presented. Freeman boundary encode vector is used for analysis. The edge pixels'label is processed Comprehensively. Then, add the edge pixels' coordinate to coefficient we get the object's area.Compared with the old algorithm, its required operations are reduced and its result is good.

Abstract:We present in this paper the production of beat wave using a single L-band travelling-wave tube (TWT) amplifier. The beat wave was first generated in a primary source using power synthesis method, then injected into a TWT amplifier to obtain relatively high power output. This approach is initiated to provide practical beat wave radiant source for high power microwave (HPM) effect research. Experimental results demonstrate that for 1～2GHz carrier frequency, it is quite practical to produce beat frequency ranges from 1MHz to 900MHz at 10kHz repetitive rate using one TWT amplifier. The output parameters of the beat wave are readily adjustable in terms of varying the feeding frequency components' power levels. The production of beat wave using single TWT amplifier takes advantages over some conventional methods since the beat wave can be formed in low power, low cost microwave sources. This method has been successfully used in certain electrical system HPM vulnerability effect experiments.

Abstract:Considering the multi-restraints among sub-tasks in parallel and distributed systems, a coevolutionary genetic algorithm (CGA) for tasks matching and scheduling is proposed based on computational model of cooperative coevolution. Simulation results show that the CGA is more effective than the conventional single population-based genetic algorithm (SGA) for multi-tasks matching and scheduling, and the algorithm is of practical use in engineering.

Abstract:Generally speaking, the spectrum of feeble signal folds the spectrum of sea clutter, and the location discrepancy between the target and its surroundings is small. So it is difficult for the classical processing in the frequency domain or space domain to detect the feeble signal in the ocean. This paper presents a new approach with Wigner-Ville distribution based on the linear frequency modulation signal detection in the ocean whereas WVD has the time-frequency local characteristic for LFM signal. It studies the difference between the new approach and the classical frequency approach for signal detection using the real data of the sea clutter collected by the radar in the condition of the several signal-clutter-ratios. The results show that the new approach has evident advantages compared with the classical approach. When the signal-clutter-ration is -14.3dB, it still detects the target effectively.

Abstract:The confirmation of the inferior distribution is the beginner and keyof Bayes statistical inference. We proposed a new method to confirm the inferior distribution of Bayes analysis based on fiducial inference point of view. The method is helpful to solve the problem of the comfirmation of Bayes inference distribution if we have few or even no inferior information. An example is given for demostrating the application of the method.

Abstract:The queueing model discussed in this paper relaxes the requirement that the service time be independent mutually and have identical distribution in GI/G/1 queue. It only requires that the retriction on service process be reduced to the degree that the service time is independent mutually.It follows that this queueing model is more rational than GI/G/1 queue in stimulating real-world systems. Under the relaxed restriction, the transient distribution of the queue length of the queueing system discussed is obtained by means of supplementary variables.

Abstract:Hybrid Petri Net is one of the extended types of Petri Nets, which is originally prompted to solve the problems of reliability and safety of the complex dynamic system. Definition of structural conflicts in Hybrid Petri Net helps to go deep into the Hybrid Petri Net's semantics. Defining structural conflicts are also very necessary and important when they are applied in analysis of dynamic system reliability and safety.

Abstract:Major issues in integration framework to support the weapon system concept design are discussed. A new architecture based on sharing product model and process model is proposed. Research on implementation of an integration framework is carried out in the light of the concept design of a weapon system. A computing sample is given considering shape design.

Abstract:We study the insurance risk models with varied kinds of general arrivals of claims by using the method of Markov skeleton processes and the supplementary variables technique, and get the distribution of the ruin time and the joint distributions of the ruin time and the surplus assets prior to and at ruin. So much progress has been made in the study of the insurance risk problems with general arrivals of claims.

Abstract:During the course of diagnosing the faults, the time for each testing point to detect the fault may be different. The problem that each testing point can detect once all the fault points that it can detect has been solved. If each testing point can detect only one fault point once, two questions will be discussed. If the sum of all the detection time is required to be minimal, an optimization algorithm is provided；If the maximum detection time is required to be minimal, the problem is proved to be NP-completeness and an approximate algorithm is given. Finally an example is given to explain the algorithms.