Abstract:The inlet distortion is a key factor of causing inner flowing unsteady of engine compressor and it greatly limits the capability and the steady range of compressor. The method of uniting numerical simulation with model analysis is adopted in the condition of distortion and a model is established which is used to calculate the transfer characteristic of the inlet distortion in the compressor. The influence of relative parameter of distortion transfer process is studied according to a third class compressor, and the axial distributing instance of the intensity and the range of distortion is calculated. The simulation result shows that the smaller the rotating speed, the weaker the export intensity of distortion of compressor; the export total pressure is distributed uniformly, and the export range of distortion is smaller under the same condition of distortion pattern. For the total pressure and total temperature distortion, the bigger the inlet range of distortion, the stronger the export intensity of distortion of compressor is. Without reference to total pressure or total temperature distortion, the radial attenuation of distortion is stronger than the circumferential attenuation of distortion for the third class compressor.

Abstract:To deal with the matter that airborne sensors may not acquire targets' parameters in combat time limitation, which leads to failure of attributes matching, a rough decision-making model for UCAV based on on-line correction time series forecasting method is presented. With the time series analysis results of sensors' data in previous time, the optimal autoregressive moving average model is constructed. With the acquired delayed data, sensors' data in future time, which would be used as an input to the process of attributes matching , are predicted and the data are corrected by on-line correction prediction method. As the analysis of an example of target threat assessment for UCAV shows, the decision-making model can extract rules in all conditions and present efficient decision-making advices.

Abstract:As new technology is adopted in the design, manufacture and use process of aircraft, the development tendency of depot test equipment has become a focus or a hot issue attracting people's attention. The paper analyzes the application of the depot test equipment in foreign army. Aimed at the actual issue of military aircraft depot test equipment, the important status and role of the depot test equipment in our army are discussed. The development of the depot test equipment under two-level maintenance system is also discussed. Finally, the development tendency of the depot test equipment is explored, which is of reference value to the development of our military aircraft depot test equipment.

Abstract:Ergonomics optimization design of keys around screen in helicopter cockpit is meaningful to the improvement of operating performance, but the research on its ergonomics characteristics in a vibration environment is a weak link. In this article, we take a new method to investigate this problem with a simulation platform. Through data analyses, some results are summed up as follows. The response time is affected by key size and its position. That the key size is 10 mm is preferable without vibration. And that it is 13 mm, or 25% bigger, in other words, is preferable with the vibration of 23 Hz which can be felt slightly by human body. Under vibration, it is appropriate that the interval between keys is 10 mm. The increase of mistakes and response time caused by vibration must be under suitable control. The result of this research is of some reference value to the ergonomics design and improvements of helicopter manipulating performance.

Abstract:In order to study the inflection of canard and strake on the aerodynamic characteristics of configuration with forward-swept wing(FSW), longitudinal aerodynamic characteristics of configuration with forward-swept wing(FSW) installing canards、strakes and canard strake combination are calculated by using three dimension N-S equations, and then the vortex mechanism is analyzed by streamlines display. The results indicate that all three models can enhance the lift-drag characteristics of FSW. After installing canard , the separated region of the wing upper-surface is diminished by the downwash effect of canard vortex and it can control the flow on the wing surface effectively. The maximal lift of the airfoil is increased about 40%. Flow separation at the root of FSW was interfered and deferred by the strake vortex after installing strake and it also produces vortex lift The lift-drag characteristics is better than primordial wing. After installing canard strake combination, canard vortex and strake vortex induces mutually, and enhance the control ability to the flow on the wing surface. The maximal lift of the airfoil is increased about 3% than installing canard; the aerodynamic characteristics are remarkably improved.

Abstract:In view of the problem that multiple targets are present in the main-lobe of the rotating radar, a method based on the idea of spatial spectrum estimation is proposed, which apples the RBF neural network theory to scanning radar. First a signal model of scanning radar system DOA estimation is presented and a high resolution DOA estimation algorithm is advanced based on RBF network. Then the lower speed of learning and convergence for conventional method is analyzed, thereafter a network learning algorithm based on fuzzy algorithm for learning vector quantization is proposed. In this method, the fuzzy weigh function of the mean of fuzzy-C and the online adaptive adjustment is adopted to determine the weigh between the input and the centre, which makes the network possess a better nonlinear approach performance and high-efficiency convergence. Both the theoretical analysis and the simulation results indicate that this network is fast and exact in estimation performance. The algorithm is effective and is of higher practical value.

Abstract:How to truly and quickly forecast the TBM impact point is a critical and decisive step in ATBM deployment and in raising the intercept probability. This paper introduces the reference frame in the process of anti-Tactical Ballistic Missile, builds up a mathematic model of impact point estimation based on the state of burnout point under proper assumption. The model is simple and precise, and the application of it can get over the shortage and abuse of the existing method. And simultaneously the error of impact point is analyzed by using the method of CEP, and then Monte Carlo simulation is done by using the model. The simulating results show that there is a small windage between the estimating value and the true value in the impact point estimation, which is actually caused by the model error and air resistance, etc., the model mentioned in this paper has a less error in impact point estimation. This just shows that the model is bettering reliability and practicality, and is of some practical meaning in TBM impact point estimation.

Abstract:In the modern aerial defense fight, target attributes recognition is related to many factors, recognition process is complex, which calls for high time efficiency. A group method of data handling neural networks classification model is set up based on rough sets, aimed at characteristics of target attributes recognition. By using the model a lot of problems are solved, such as the low efficiency while high dimension data sets are used to train the neural networks and the neural networks configuration scale is great. Meanwhile, in order to boost the attributes reduction efficiency of high dimension data sets, the set approximate quality reduction algorithm is improved. Finally, in contrast with the simulation result of BP neural networks, the result shows that the classification quality of group method of data handling neural networks classification model based on rough sets is better than that of BP neural networks model, which satisfies the requirement for target attributes recognition in modern aerial defense fight, the attributes reduction algorithm based on speediness seeking core and set approximate quality is rapid and efficient.

Abstract:An improved FCM-based multi-target tracking data association algorithm (MFCMDA) is proposed to overcome the combinatorial explosion of calculating volumes when multi-objective data are on the Internet under the clutter environment. The forecast track would be converted into various sensors in space as their own observations of the cluster, and by substituting the membership measured by all quantities belong to the goal instead of associated probability in JPDAF, the multi-objective data associated problem can be converted into a fuzzy clustering one in performing associated computation. So the improved FCM based multi-target tracking data association algorithm can be taken to realize the association of track and measure by effectively using the historical information in target state estimation. The improved FCM based multi-target tracking data association algorithm is superior to the JPDAF algorithm in computation. The simulation results show that the method is effective.

Abstract:The micro-Doppler signature is referred to as the unique signature of micro-motion target, which is significant for classification, recognition and imaging of special target. Because of the non-linear and non-stable characteristics of the special signal generated by micro-motion, in order to extract the micro-motion signature and provide a basis for target classification and identification, this thesis takes the object with rotating parts for example, under the single frequency system, to extract the micro-Doppler information based on the time-frequency analysis method. Then the micro-Doppler signature of micro-motion is obtained by simulation and verification, the transformation results and the differences of performance by using common time-frequency analysis tools are compared. The simulation testified that Gabor Transformation is feasible and stable in the aspect of extraction of micro-Doppler information, the remarkable potential of Gabor Transformation will provide a new approach of signature recognition for micro-motion target.

Abstract:In order to realize fuzzy comprehensive evaluation of the information warfare of air defense and clear off the redundant data, in indexes membership, which are not useful for goal classification, and based on data mining of entropy, mining knowledge information about object classification hidden in every index, the relation between object classification and index membership is affirmed, the redundant data in index membership for object classification are eliminated by defining distinguishable weight, and valid values are extracted for computing object membership. A case of the information warfare of air defense is adopted in this paper. Empirical results show that: In order to clear the interference of redundant data, the membership conversion model can be used as a valid method with multiple indexes attributes. By using the method based on data mining of entropy clear the interference of redundant data in fuzzy evaluation is cleared off and many multiple indexes decision-making problems are solved.

Abstract:To improve the information safeguard capability of joint air-defense operation, a concept of joint air-defense battle-field information apperceiving system is proposed. The research way of the evaluation indexed system of the information apperceiving system is analyzed from the view of system construction, function and military requirements. Based on these, the principles of system effectiveness evaluation indexed system and the first level tactics indexes are brought forward. By adopting the Grey theory and adopting the grey synthesis judgment method, the effectiveness of information apperception system is evaluated, thus diminishing the influence of the ambiguous information during the evaluating process .These provide a reference to the joint air-defense battle-field information apperceiving system constructing and effectiveness evaluation.

Abstract:The returned signal of low-attitude flying targets is often jammed by the strong ground clutter, so it is a difficult problem to eliminate the clutter effectively. Then, cancellation is a simple and valid method of eliminating the ground clutter. In the paper the cancellation of ground clutter in ISAR imaging of frequency-stepped chirp radar is presented. The identical amount of stretching time-delay with the adjoined bursts of echo is applied in the signal stretching process, and then the ground clutter is filtered by cancellation. After cancellation the coherent signal can provide useful data for the successive ISAR processing. Simulation results show that the proposed method is robust and effective, hence, it is a valuable approach to ISAR imaging of low-attitude flying targets.

Abstract:The multiple access protocol in data link will directly influence its performance and the weapon data link requires higher real time in message transmitting, so this paper presents a D-TDMA(Dynamic Time-Division Multiple Access) protocol supporting QoS(Quality of Service) in Weapon Data link network topology by ameliorating dynamic slots allocation algorithm, gives out the average end to end(ETE) delay formulae of different priorities traffic. A simulation model of weapon data link is created by OPNET, and then the influences on network time delay performance of different frame lengths are compared. The simulation results show that the D-TDMA scheme can meet the requirement of time delay, and provide high channel utilization in Weapon Data link communication.

Abstract:TCP Vegas can provide a better performance compared to the traditional TCP Reno scheme. However, when TCP Vegas and TCP Reno connections coexist and share the same link in wired network, there exists a serious incompatibility problem of unfair bandwidth sharing in favor of TCP Reno. To solve this problem, by adding monitoring algorithm of the network state based on relative queuing delay to TCP Vegas-A, an enhanced Vegas algorithm is proposed, termed TCP Vegas-A+. TCP Vegas-A+ can adjust the congestion window more properly and timely by classifying the network state into congestion increase and congestion decrease. We analyze the compatibility of Vegas-A+ and Reno connections by computing and comparing the congestion window size and the number of transmitted packets in congestion avoidance phase, and compare it with the compatibility of Vegas+ and Reno connections. Mathematical analysis and simulation results show that, TCP Vegas-A+ algorithm improves the compatibility with TCP Reno and has a better capacity in competition with the Reno for bandwidth than other improved Vegas algorithms.

Abstract:Based on the evaluation technology of multi-value about invulnerability, the invulnerability of the communication networks is evaluated in the view of battle. First, an evaluation model is built. In the model, some invulnerable indexes about which the clients are concerned are selected. The variation can incarnate the fluctuation of individuals. Second, the strategy of attacking vertexes, which has been used in many articles, is not adopted. But the more practical strategy is that the vertex which emerges most frequently in paths is searched and attacked. Finally an example of network is analyzed by using the model, the analysis result shows that the model can be used to evaluate the invulnerability of the communication networks and tell that which part of the network structure needs optimization.

Abstract:Using plane element and three-dimensional element of finite element method to calculate stress concentration factor (SCF) of symmetrical U-shaped notch sheet under tensile load respectively, a conclusion is obtained that the computing results of the plane element are always lower than those of the three-dimensional element. On the basis of this, a comparison is done between the results of three-dimensional element and the computing results from Neuber's formula and from Barrata-Neal's formula. It is found that, compared with the FEM results of the 6 kinds of notched sheet, the deviation of the results obtained using Neuber's formula ranges from 8.5% to 13.3%, and the maximum deviation of SCF got by Barrata-Neal's formula is 5.5%. In view of these facts, the results from Neuber's formula and from Barrata-Neal's formula are modified using FEM results，what is more, the modified formulae for estimating SCF of U-shaped notch sheet under tensile load are obtained.

Abstract:Based on the coordinate transformation theory, this paper utilizes the square Split-Ring Resonators as the unit cell main body and designs a two-dimensional invisible cloak. The CST Microwave Studio is used to optimize the different layers' structure of the invisible cloak with the frequency of 8.5 GHz. The designed two-dimensional invisible cloak is fabricated and measured by the plane wave-guide system. The measured result verifies that the cloak made by the designed metamaterial has a better invisible capability. This research gives a realizable way which makes the things inside the cloak unable to be detected.

Abstract:Command style can be divided into concentrating command and dispersing command based on the concentrating degree of command power. This paper explores a new method of command style decision making analysis based on the fuzzy rough sets and fuzzy reasoning. Firstly, the factors, including command and control measures and information guarantee level, that have an effect on the command style are analyzed. The knowledge discovery method of the command style is studied and given based on the theory of fuzzy rough sets. Then, by means of the obtained fuzzy reasoning rules, the quantity decision making conclusion of command style can be obtained by the Mamdani fuzzy reasoning algorithm with multiple inputs and rules. Finally, a reasoning system based on the fuzzy logic tool box of matlab7.0 is established. Through deducing by this system, three kinds of simulation conclusions that are accordant with the subjective judgments of military experts are obtained. This simulation system can be brought into the operation decision making support system.

Abstract:A design method of a nonlinear vibration controller for smart piezoelectric structures is proposed based on resetting differential equations. A nonlinear vibration controller which fulfils the Lyapunov stability is worked out by emulating the effect of the switching system with piezoelectric shunt damping. A dynamical model of the plant and the control algorithm of the controller are developed, the inductor, the resistor and the switching action in the emulated circuit only "exist" as numerical representations inside the controller. The controller overcomes the disadvantages of the passive piezoelectric shunt damping technique, eliminates the need for a large physical inductor and has less sensitive to environmental changes. The simulation results for a cantilever beam show that the controller can suppress the structural vibration of controlled mode effectively and also has a certain contribution to vibration suppression for the other modes.

Abstract:In practical applications, the forward security and public verifiability are very important to cryptography. An authenticated signcryption without using Hash and Redundancy functions is analyzed in this paper, and the result indicates that the scheme does not possess the characters of forward security and public verifiability. Modified schemes are proposed respectively according to each character mentioned above, and theoretically proved. By adopting the modified schemes, the original scheme's defects of non- forward-security or non-public-verifiability are overcome, and the computational cost and communication overhead are not increased.