Abstract:The inserted-board air flow inlet distortion test shows that dynamic pressure at the engine inlet exit section can be divided into undisturbed, mixing and low pressure areas. The main turbulence flow power is distributed in mixing areas, with the value characteristics of low frequency distribution and wide range. It is basically in a normal distribution. The main power is distributed within 100 Hz. Its scale is 6 times higher than that of low- pressure area, and is the main area that affects the distortion degree. Also, the turbulence distributions of other two areas are analyzed and an analyzed result is obtained. It is discovered that with the inserted-board raised and especially when the engine operation point is moving to surge boundary, many dynamic pressure frequencies will gather to a small range, the low frequency wave power will increase in large scale, and full of all distortion area. At last, it arouses the engine stall. The primary analysis indicates that in air inlet the airflow presents self-excitation vibration during the trouble by strong distortion.

Abstract:The finite volume method is used to solve 3D Reynolds average N-S equation by RNG k-εturbulence model. Flow phenomena in nozzle using secondary flow thrust vector control technology with the change of the jet flow angle are numerically simulated. The result indicates that the vector angle of thrust is maximal with the injection flow plumbing at the wall. The angle of injection flow has a significant effect on the thrust vector angle, and the reversed jet flow can produce greater thrust vector angle and thrust loss than the parallel jet flow.

Abstract:This paper analyzes the aerial combat situation assessment of Multi-group aircraft under Command of AWACS. Combined with the conventional methods in situation assessment, a model integrating with distance - superiority, angle - threaten factor and speed - threaten factor is founded based on Set Pair Analysis. In this method both mutual factors and other factors are taken into account. The combination mode explains that the situation assessment is performed among all the formations. Numerical examples of simulation show that the concept of Potency in SPA can directly reflect the state of aerial combat situation, and the analysis of uncertainty reflects the situation change comprehensively.

Abstract:To build an appropriate mathematic model of the random drift of flexible gyro, two methods are discussed, using non-stationary time series analysis and using stationary time series analysis based on wavelet discomposition. The experimentation results indicate that the two methods are accurate and effective.

Abstract:The potential applications of modeling and simulation on flight supporting process are proposed. Using discrete event simulation (DES) method, the vehicle schedules in Airfield Station Flight Supporting in both active and passive supporting mode are modeled and simulated, based on which, an illustration is given on simulation platform ARENA. According to the simulated results, support time of active supporting mode under network situation can be reduced by 3.25 minutes compared with the traditional passive supporting mode, and the supporting efficiency is improved by 10.6%.

Abstract:Cost prediction of unmanned air vehicle (UAV) is an important and a considerable problem in the design and development phase of equipment. Since the cost prediction of UAV with few observations has some characteristics like uncertainty, etc., a cost prediction model based on least squares support vector machines (LS - SVM) is presented and applied to both the development cost and the maintenance cost prediction problems in this paper. The results show that the model is of better precision in cost prediction.

Abstract:Localization of sensor nodes is an essential requirement for many wireless sensor network applications. As most sensor positioning equipments are complicated and costs prohibitively high, this paper presents a low cost system based on measurements from a pedometer and communication ranging between neighboring nodes. The information is fussed through a probability-based localization algorithm. Unlike most of the existing methods that require good network connectivity, the proposed system works reasonably well in a spare network. An experimental prototype has been developed and the practical results are used to evaluate the system's performance. The results show that the system performs well.

Abstract:A new method of increasing the versatility of the Graphical Computing Method is presented. The disadvantage of changing the size of the viewing volume according to the size of the targets is overcome, the aim that the targets can be shown in the view port absolutely and divided as small as possible is realized, and the versatility of the software is improved. The computation result by using the method presented in this thesis is consistent with the result in the literature, which shows that the method presented in this thesis is feasible.

Abstract:In order to obtain the effectual feature of signals, wavelet packet transform is used. The characters of every wavelet packet basis are different, which can express the main feature of a signal. The local discriminant basis (LDB) is calculated based on the distance criterion, and a feature extraction method is proposed. The feature vector, which expresses the energy of sub-space in LDB, is obtained by using Fisher criterion for feature choice. The classification experiment for three different classes of targets is done. The results of the experiment show that this feature extraction method is effectual in pattern recognition.

Abstract:For passive inter-modulation interference of microwave and RF communication system, the non-linear principal mechanisms due to electron tunnelling of metal oxide are analysed and discussed firstly. Mathematical model of the third order PIMP of Al - Al2O3-Al in antenna is constructed. Based on the results of the third order PIMP, the fifth order PIMP is calculated by using power series, and the comparison among the PIMPs produced by different alumina is done. Numerical and measure results indicate that oxide's PIMP power level increases with the increase of input power, and increases with the increase of oxide's thickness.

Abstract:On the basis of analysing the characteristic of Air-raid target stream, a conclusion is reached that the Air - raid stream can be taken as flow -Palm in research. For the different air -raid modes, relevant models about the interval distributing of air-raid formation are introduced. That provides the basis for quantitative analysis of the air defence deployment and simulation.

Abstract:The optimization on demand of initial spare part in equipment is a complicated nonlinear mixed integral programming problem, and it is a key factor affecting the cost and efficiency of weapon system. In order to reduce the cost and improve the reliability of equipment, a new particle warm optimization (PSO) method, which can be used to find optimal regions of complex search spaces through the interaction of individuals in a population of particles, is constructed to solve this optimization problem and the best scheme is achieved. The test shows that this optimization method is scientific and valid for this problem.

Abstract:In this paper, the feature vectors of the roller bearing signals are extracted on the basis of wavelet analysis and a fault diagnosis experiment is carried through wavelet neural network in detail. The method and the theory of fault diagnosis based on BP neural network and the radial basis function neural network are studied and the results of diagnosis based on relax-type neural - networks and close-type neural-networks are compared.Simulation results indicate that diagnosis based on close-type networks more effective.

Abstract:Most papers on detection intrusion problems made by past researchers usually employ rule portfolio to match attack data packages and appear unable to keep the system in optimized detection status when the detection probability is unknown or varying. In this paper, the method of rule set election is improved and the optimal solution via establishing convex relaxation function is gained, then attack package is matched with it. Finally simulation is done with computer, which shows that the effect is better than that of the BM method.

Abstract:It will reduce the space relativity of original image information and strengthen the randomicity of encrypted information and largely improve the safety of watermarking system if the image had been encrypted during the phase of initializing digital watermarking. Logistic chaotic sequence has been used in shuffling and encrypting the binary image widely, because it sensitively depends upon its initial value and it has the statistical characteristic like which the white noise has. But the original Logistic arithmetic can't encrypt the gray image that can record more information. The paper has designed a new encrypting arithmetic which is based on expanding the bits of mapped sequence and Logistic chaotic sequence. The experiment shows that the new arithmetic is excellent and effective in encrypting the gray image, and also is safer and faster than Arnold arithmetic in encryping the gray image.

Abstract:A method of combining RS frequency coding and LT coding concatenated for wireless data transmitter-receiver is presented in this paper. Its superiority to the traditional LT code in decoding probability is analyzed as well. The proposed method features well in performance in the application of mass data transmission in low signal-to-noise ration environment. The results of simulation indicate that this method can recover the transmitted information efficiently and improve the quality of the received image even under the condition of low signal-to-noise ratio.

Abstract:The channel model of MIMO system is introduced first, then the effect of Rayleigh fading on the symbol error probability for 16-QAM and the performance on the capacity of MIMO system are analyzed based on this. The performance of MIMO system in slow flat Rayleigh fading channel is studied from these two aspects including spatial multiplexing and spatial diversity. The results of analysis and simulation show that the symbol error probabilities of spatial multiplexing system realized by V-BLAST algorithm increase with the increase of the number of transmitting and receiving antennas. And different diversity combing techniques have different influence on the system performance in which MRC is the best, EGC takes second place and SC is bad; and the symbol error probabilities of spatial diversity system decrease with the increase of the number of transmitting and receiving antennas.

Abstract:This paper presents a chaotic neural network (CNN) model through adding chaotic control quantities to each neuron. The chaotic control quantities are used to control the neural network energy function increasing, decreasing or keeping unchanged which can help the neural network to enlarge searching space to get optimal solutions and avoid local minima or invalid solutions. In order to study the delay bound and the least cost multicast routing problem, a new algorithm based on CNN is proposed to optimize the multicast tree with delay bound, and the energy function is defined to represent the cost of optimal path with the delay bound. Through the comparative simulation with other algorithms, the results show that the proposed algorithm is both efficient and feasible in constructing the optimal delay bound multicast tree.

Abstract:Grey theory is applied in evaluation of electronic equipment succession degree, the evaluation system based on stratification structure is established. At the same time, more stratification evaluation models and algorithms are discussed. In the end, a simulation evaluation example is given, which shows that the model is effective and feasible.

Abstract:Based on I - V characteristics of single-electron transistor and the idea of MOS digital circuit design, an inverter using the single-electron and MOS transistors is proposed and some other logic gate circuits are educed. Finally a novel half adder circuit is realized using these logic circuits. The half adder circuit, in comparison with the pure CMOS circuit, has the advantages that the number of transistor is decreased, the structure of the circuit is predigested, and the total static power consumption is reduced. The accuracy of the circuit is validated by SPICE.

Abstract:Based on IFS and data fitness technique, and in consideration of the effects of both the membership and the non-membership, an approximate reasoning method of IFS is proposed. First, the definition of IFS and a method of data fitness are given. The reasoning process of GMP and GMT is discussed. Second, the emphasized investigation is made on the techniques for approximate reasoning on IFS. Finally, the correctness and validity of the proposed method is verified by a concrete instance.

Abstract:According to the specialty of infection transmission that infected individuals have different infectivities in different stages and that infected individuals can move from a stage into the other stage with the development of infection, an epidemic model with stage is established. The basic reproduction number is found by means of the next generation matrix. By applying the theory of asymptotically autonomous systems, the following results are obtained: the disease-free equilibrium is globally asymptotically stable when the basic reproduction number is not greater than 1; the endemic equilibrium is locally asymptotically stable when the basic reproduction number is greater than 1. When the disease is not fatal, the endemic equilibrium is globally asymptotically stable if it exists.

Abstract:In this paper, we introduce the uniform continuity of functional on a metric space and the test function of a uniform continuity.The character of test function and the relation between the test function and the uniform continuity are studied.Using the test function, we obtain a necessary and sufficient condition of determining the uniform continuity of functional on a metric space or a sub-normed Z-linear space. In this case, it is simple to determine the uniform continuity of functional.

Abstract:The effect of ART reagent on the frication performance of 45 steel/cast iron pair is studied by using an improved friction apparatus. The ART reagent is added to the pair, and then the friction experiment is carried out at constant load and velocity under air condition. Emphases are mainly put on the mechanisms of surface modification and abrasion - resistant rule. Investigation by microscope indicates that many particles, such as the elements of ART reagent, are embedded into the surface. The micro-penetration hardness and surface roughness are greatly increased and decreased respectively, which demonstrates the pronounced abrasion-resistant effects of ART reagent.