Abstract:The Unmanned Aerial Vehicle (UAV) with variable forward-swept wing is a new design concept, which integrates the advanced aerodynamic characteristics of orthogonal wing, delta wing and the forward-swept wing. The best performances under different mission demands can be achieved through changing the wing position among the three said configurations. The design of wing-body revolved mechanism, as a key technique, must be hard enough to suffer the lift and moment during varying wing, moreover, the fuselage can not be overweight. Thus, a mechanism with a annular locking groove is proposed in this paper, the high-pressure oil controlled by electromagnetic valves can drive the wing revolution and disperse the stress concentration on root wing through the two sides of annular locking groove.

Abstract:Based on the man-machine-environment complex system, pilot reliability, air traffic control personnel and aircraft maintenance crew are analyzed. The virtue and disadvantage of reliability evaluation method are studied. A flight safety human reliability evaluation model is built by Bayesian Networks. For this model, diagnosis inference and sustaining inference are utilized. The analysis progress is intuitional and the calculating progress is convenient. Thus the model is applicable to the men-machine-environment complex system modeling.

Abstract:In this paper, spring analogy method for dynamic unstructured grids is studied. The stiffness of the springs in the modified vertex spring analogy is analyzed. The standard method is improved in consideration of preventing extrusion, torsion stiffness coefficient and the boundary effect. Applications of the improved spring analogy method to 3D-grids generation show that the new method greatly upgrades the deforming ability and the quality of the grids. Coupled with 3-D ALE Euler solver this dynamic unstructured grid method is applied to simulating transonic unsteady flow about a rectangle rigid wing and a high-aspect ratio sweepback wing. The computation results are in good agreement with those of the literatures and experiments.

Abstract:A sliding model variable structure controller with auto-adjusted reaching law is researched in this paper. In the research, switch function s is taken as an error and reaching speed is adjusted by PID controller, with the intention of minimizing the traversing speed when arriving at the sliding model surface to reduce chattering and optimize the arrival time. According to the aero engine steady mathematic model, the sliding model variable structure control law is designed, the aero engine's sliding model controller based on PXI bus is constructed. The part-actual simulation results show that the controller is of swift response, tiny high-frequency chattering and is strong in robustness and tracking.

Abstract:The method of Maximum Entropy Spectrum Estimation is used to extrapolate four airplane data, and ISAR imaging is done on the basis of it. The four characters of ISAR images, i.e. geometric moment, invariants based on geometric moment, shape and quantized energy belt are adopted in the study of the arithmetic theory of linearity and non-linearity about SVM, and a method of target recognition and classification based on SVM is proposed. The M-ary method for multi-target classification is used to classify the airplanes, and 40 different data fields of each target are chosen for imaging. Compared with the usual BP and RBF neural network algorithms, this method is good in recognition, and its discrimination can reach 97%.

Abstract:Because of sensor own characteristic limit, or in interference situation, the target information obtained is incomplete, in order to take full advantage of those incomplete information, an idea of target coordinates information-processing is presented. The cotangent relations theorem is given, and other theorems and the deduction application methods are summarized and compared, many useful algebraic formulas are inferred, pure information processing principles, are obtained, on azimuth, pure elevation angle and pure distance from the theory principle, then the target tracking problems are solved. Using this principle method means taking a great stride in realizing the information fusion project. Contrasting the geometry theorems and deductions of several similar graphs, summarizing these algebraic relations and applying both of them to the air defense information fusion are of important theoretic significance.

Abstract:This paper compared the Doppler frequency and azimuth frequency in detail during the researching of a representative bistatic SAR imaging theory and found that using Doppler frequency instead of azimuth frequency in the general SAR processing with traditional imaging algorithms has little influence on the azimuth resolution of the fine imaging , the error is less than 4%. But if the differences between the two frequencies are neglected in the condition of larger squint angle, bigger transmit signal chirp rate, and longer wave length, the azimuth resolution error may reach as much as 10% even 27%. So, whether Doppler frequency can be used instead of azimuth frequency depends on the SAR systems with different specific parameters and the different requirements in specific imaging precision.

Abstract:To accurately choose the air attack target and obtain the maximum fire effectiveness, an anti-aircraft weapons target selection strategy based on the Markov process is proposed, which is formulated by looking on the threat degree of the air attack target as the target function. First, the strategic matrix of firepower assignment is defined, then, the state transfer matrix in the target selection process and anticipant benefit function after firing a object are given. Finally the average benefit of anti-air warfare system is expressed by using the firepower assignment strategy. Using this method the objective can be selected instantaneously to adapt battlefield campaign position. Simultaneously an analysis and verification have been done through an example, the results show that this method is feasible and can satisfy the battlefield operational requirement.

Abstract:To solve the problem of frequency trait and direction-of-arrival (DOA) simultaneous estimation of linear frequency modulated (LFM) signal under impulse noise, and according to the FLOM-Time Frequency Distribution (TFD) theory and spectrum reassigned method, a new algorithm of Frequency Trait and DOA Simultaneous Estimation is brought forward based on the reassigned FLOM-Time Frequency Distribution (TFD). This algorithm can be applied in impulse noise environment, while the conventional Time Frequency Distribution DOA estimation methods can not. And the algorithm can be used to depress the influence of TFD cross-terms and is good in time - frequency collection. In using this algorithm, the LFM instantaneous frequency and DOA value can be obtained by frequency fitting and Time Frequency Average -MUSIC method. Compared with the similar DOA algorithms in existence, this algorithm is more accurate in estimation results. Simulation results show that the algorithm is effective.

Abstract:ISAR imaging has been the focus in recent years. Based on Doppler, the one-dimensional imaging is obtained. Through range alignment and auto-focus, the target can be equivalent to a rotation model. Based on the rotation model, the movement of the ship target will be divided into a horizontal component and a moving component. The first one is useless in the ISAR imaging, so it must be compensated. This is the important step. Based on the rotation model, for the moving smoothly ship, the two-dimensional ISAR imaging can be got through range alignment and auto-focus. But the apriori knowledge of ship target motion is generally unknown, because of their uncooperative moving, the echoes have an obvious time-variant character. Based on the periodicity of Doppler frequency, the whole dwell time is divided into several intervals, then, based on the above, the instantaneous ISAR imaging of every time interval can be got and simulations are done to verify the method. The verification result shows that the method is effective for the non-stationary ship imaging.

Abstract:Joint fire attack is the most important operation modes in modern wars. Based on the analysis of the joint fire attack's circle process, the optimal time cycle of target assignment is put forward. According to the states of both sides and the battle situation updating, a thinking mechanism for target assignment is established. Connecting with the input variable and the constraint expression, a linear programming model is made up through separating the battlefield into girds to reduce the complexity of target assignment. At the end, an example is given to verify the model. The use of this model can optimize the weapon target assignment, which provides a quantitative analysis tool for setting down the campaign scheme.

Abstract:The evidence classification strategy is a useful conflict evidence reasoning and fusion method, but in practice it would bring a great deal of repetitive class. In order to reduce the number of class and improve the efficiency of evidence classification strategy, an evidence classification strategy based on similarity of evidence is proposed. First by taking the initially evidence in evidence reasoning as the ideality evidence, scaling the distance between each evidence and the ideality evidence, the evidences in the system are divided into two classes according to the similarity of them. Then the classification will continue with the above classification strategy till it will be impossible. Finally the following workings such as combining the classified results with Dempster combination rule, scaling the reliability of the classification results and weighting the Dempster combination result are done. The strategy is validated through an example. The result shows that the evidence classification strategy based on similarity of evidence can reduce the number of class effectively.

Abstract:Spare parts support plays an import role during wartime. In order to meet the requirements of Precision Support, spare parts support must be planned deliberatively prewar and be executed flexibly to deal with various uncertainties. Based on the similarity between the wartime spares support system and the multi agent system, Agent based modeling and simulation methods are adopted to investigate the dynamic coordinate mechanism during the wartime. Groups in the multi-agent system's structure are described on the bases of the relationship between the Agents. To decide how to supply spares dynamically during the wartime, the new multi agent reinforcement learning method is designed and presented. A simulation example is illustrated in the end and the simulation result shows that the method is effective.

Abstract:This paper presents a model validation method based on neural network by analyzing, in detail, the subsistent problem of model verification method in application. In this method, by using the powerful ability of nonlinearity mapping of neural network and learning the key properties of the behaviors of various models, the real system behaviors are classified as coming from one of the models, thereby evaluating the credibility of the models. In the concrete process, input and output of models are used as the training set to train neural network firstly, then the matching degree of models and real system is ascertained by the sendout value (probability vector) of the trained neural network when the actual system acts on the trained neural network. Simulation results of the final image target recognition models lastly further show the feasibility and validity of this method. Therefore, this model verification method based on neural-network can be used to verify the modeling nicety degree of complex uncertainty system.

Abstract:Anti-Collision is one of the key problems in RFID system. Aiming at the deficiency of Query Tree Algorithm that the complexities of query and communication are increased due to adding prefix seriatim, an improved algorithm called Collision Tracking Tree Algorithm is proposed, which updates query prefix using collision position. By designing the collision position tree, the communication complexity of this improved algorithm is analyzed theoretically. On the assumption that the collision bits are continuous, three lemmas and a theorem about the reader communication complexity are presented and proved in detail. Finally, the performance of the algorithm is simulated by using MATLAB. The simulation results show that the reader communication complexity of collision tracking tree algorithm is better than the query tree algorithm based on the assumption that the collision bits are continuous. So, in the normal instance using the proposed algorithm can reduce the complexity of communication and save costs of the system effectively.

Abstract:When open circuit failure occurs in single-Phase or multiphase of the six-phase permanent magnet fault tolerant motor, if the current flows of the remained phases are not adjusted, the torque ripple will be too large and the performance of the motor will be obviously reduced. In this paper, assuming that phase A is at fault, in order to preserve the performance of order, the mathematic model under five-phase stationary coordinate is set up. By performing dummy coordinator transformation for it, the decoupling control of the fault motor is realized, and vector control of it is possible. The simulation model is also set up and the simulation result indicates that, by changing the value and phase of the current flows of the remained phases, the motor can still operate in a normal way and preserve its performance in a normal state, therefore, the fault tolerant control of the motor comes true.

Abstract:In this paper, by conducting an investigation in signcryption schemes with forward security and public verifiability and based on Liber and Quisquaters signcryption schemes, a new signcryption scheme is proposed, and its security and efficiency are analyzed at the same time. The result shows that the new signcryption scheme proposed can provide forward security and public verifiability simultaneously; moreover, it has the property of shorter length of parameter key and simple management is simple compared with the traditional PKI owing to the use of Id-based PKC and bilinear pairing technique in the scheme; therefore, it has the same efficiency with the LQ signcryption scheme. This work of giving such an efficient and secure signcryption scheme is not only significant in theory in solving the related public problem but also has practical value for the high level requirement of practical application such as the electronic business.

Abstract:This paper investigates the LDPC codes decoding algorithm over Additive White Gaussian Noise (AWGN) channels, analyzes the reason that incidental error appears in decoding process, and points out the reason why the incidental error appears is that there are loops in the parity-check matrix. Then a software method, which restricts incidental error, is proposed for decoding LDPC codes. In using this method the incidental error caused by loop's influence can be effectively restricted only by properly controlling the decoding program of LDPC. By this method, decoding performance of LDPC codes and decoding program stabilization are improved greatly, and the application of LDPC codes can enter more fields.

Abstract:To solve the problems such as the unfairness existing when standard TCP connects with different RTT competing bandwidth, the window over-fast growth caused in the late phase of slow start and etc., a new TCP slow start algorithm for improving, termed SS+, is proposed. In the early slow start phase, using SS+ can keep the congestion window exponential grow; in the late phase, the window control growth factor in direct proportion to RTT is introduced to increase the congestion window of TCP connecting with larger RTT faster, otherwise the increase will be slower. Performance analysis and simulation results show that by using SS+ algorithm the congestion window growth rate is slowed down and the TCP connection with smaller RTT in the aggressive bandwidth competition is weakened in the late slow start phase. To a certain extent, by using SS+ algorithm a fair sharing of available bandwidth between TCP connections with different RTT is obtained. And SS+ algorithm is easy to realize and only requires the TCP source revised. This SS+ algorithm has some theoretical and practical application value.

Abstract:Nonionic poly-N-isopropylacrylamide (PNIPAM) and anionic poly(N-isopropyl-acrylamide-co-methacrylic acid) (P(NIPAM-co-MAA)) micro-gels containing Cd2+ are prepared by employing inverse suspension polymerization method. PNIPAM/CdS and P(NIPAM-co- MAA)/CdS composite micro-spheres with patterned surface structures are prepared by using micro-gels as micro-reactors and templates and inputting H2S gas slowly to confine and direct the precipitation of CdS. The surface morphologies of the composite micro-spheres depend upon the composition of the templates. SEM measurements indicated that the micro-spheres prepared are about 50 μm and occupy pursued core-shell structures. XRD indicated CdS precipitated within/on the template is in a crystalline state, and belongs to cubic crystalline system. Fluorescence measurements indicate that the emission of the micro-spheres is characterized by CdS, and the emission is slightly affected by the composition of the template employed.