Abstract:A twodimensional axisymmetrical numerical flow model with secondary combustion and trail cover moving boundary is established to study the influence of volume change in initial chamber on the load and the internal ballistic property. On the basis of experimental data verifying the reliability of model, the mechanism of flow field and the secondary combustion core region change caused by volume change of initial chamber is investigated, and the dominant factor influencing building pressure in the rejection process is analyzed, and flow field, load and internal ballistic characteristics of different initial volume are obtained. The results show that with the increase of height in the initial chamber, the reflection point of jet flow is transferred from the cylinder bottom to the cylinder wall, and the secondary combustion core region is transferred from the upper part of cylinder to the lower part. For the initial pressurepeak, volume factor is leading, and for the second pressurepeak, the total pressure is leading. The peak values of missile acceleration and the outlet velocity decreases firstly and then increases, and the time out of tube becomes longer, and then becomes the shorter. The height of the initial chamber of the experimental device increases by 100mm, which is one of the most optimal interior ballistic designs.

Abstract:In consideration of the great Impact of missiles on air combat, the continuous and multidimensional state space and the weakness of traditional approaches in ignoring opponent’s strategy in the air combat, reinforcement learning is applied to 1vs1 beyond visual range (BVR) air combat maneuvering decisions. Firstly, a new reinforcement learning framework is built to decide both sides’ maneuvers. In this framework,ε-Nash equilibrium strategy is proposed to choose action, and reward function is revised by missile attack zone scoring function. Then, by using a memory base and a target network, Q-network can be trained, forming a “value network” for BVR air combat maneuvering decisions. Finally,Q-network reinforcement learning model is designed, and the whole maneuvering decision is divided into learning part and strategy forming part. In the simulation, considering that the enemy in the air combat confrontation adopts a fixed maneuver and the two sides are both agents, the former agent wins, and the latter has the advantage of the situation to win, verifying that the agent can perceive the situation of air combat and make a reasonable BVR air combat maneuver.

Abstract:This paper studies the influence of buoyancy on the heat transfer of the supercritical pressure level under different gravitational acceleration by the method of enhanced wall treatment combined with the RNG two equations, establishes and verifies a calculation model, and analyzes the thermal physical property of RP-3 aviation kerosene within the pseudocritical temperature. The applicability of the discriminate criterion of convective heat transfer is also analyzed. The results indicate that the drastic change of the thermal properties of kerosene within the pseudocritical temperature will cause a stronger secondary flow in the horizontal circular tube because of the effect of buoyancy lift. In the secondary flow, the convective heat transfer of the upper wall decreases, the convective heat transfer of the lower wall enhances, the friction resistance of the lower wall increases and the friction resistance of the upper wall reduces, and at last the loss of flow pressure increases. With the acceleration of gravity increases, the influence of floating lift on heat transfer and flow is more significant. From simulation it can be seen that the laws of the influence of floating lift force on heat exchange of the supercritical pressure coal oil can be described by Protopopov criterion.

Abstract:By utilizing the new epoxy asphalt concrete pavement (SEA) structure model with the soft Bisar and ANSYS, the main gear configuration and multiple load parameters are analyzed. In the analysis, the influence of the stress and strain and the deflection on surface course pavement are not only calculated, but also the inflection threedimensional interpolation picture fitted by Bisar. When the A380 aircraft is acting on the SEA pavement, the results show that the six wheels in front of main landing gear bear load mainly and the stress and strain distribute uniformity with double peak phenomena. But for the four wheels in rear, the stress and strain on the direction of Y are more than X with concentration phenomena. In addition, a large aircraft like A380 aircraft acting on the epoxy asphalt concrete pavement(SEA) has lesser deflection, having better mechanical effect compared with the normal asphalt concrete pavement(SAA).

Abstract:In view of the PIO (PilotInducedOscillation) problem prone to occurrence in ultralowaltitude airdrop, a closedloop system with actuatorrate limitation is established, and the formula of PIO of the closedloop system is deduced. Based on the synchronization and Neal-Smith model and the different actuator saturation values, the descriptive function method and the GAP criterion are used to predict the PIO trend. The results show that the PIO prediction results are different for different pilot models. Compared with the NealSmith pilot model, the synchronous control model is more effective, and predicted by the simultaneous control model. When the absolute gain of the driver is greater than 11.5, the closedloop system is unstable and prone to PIO problems. If the PIO is induced by the pilot, the occurrence of PIO can be effectively avoided by reducing the manipulated gain for the pilot. Within the reasonable and permissible range, The limit value avoids the occurrence of PIO to a certain extent.

Abstract:Unmanned combat platforms will be the main combat force in the future airfield. Cognitive navigation is a new kind of navigation technology which is proposed for the need of intelligent autonomous operation control of the unmanned platform. In this paper, we firstly made an indepth analysis, proposed the basic connotation, framework structure and information processing flow, and analyzed the new navigation abilities of cognitive navigation. Secondly, we explored a new approach to cognitive navigation using braininspired technology. Lastly, we proposed the key technologies needed to be solved to realize cognitive navigation. This paper provided a theoretical framework for the realization of intelligent autonomous capability of unmanned combat platform, and had strong guiding significance.

Abstract:Radar absorbing materials (RAM) can effectively inhabit the transmitted waves and the reflected waves widely applied in the field of stealth technology, electromagnetic shielding and compatibility, as well as wireless communications. Suffering from frequency dispersion of electromagnetic parameters, the traditional EAMs still be up against a challenge in further improvement of broadband absorption in the low frequency. Recently, with the development of metamaterial design, the achievement of broadband absorption based on metamaterial configurations exhibits more performance improvement due to its flexible capability of electromagnetic manipulation. The paper centers on the research progresses in radar absorbing materials based on metamaterial structure with the aid of development background, design principles and property characteristic. Specifically, the broadband radar absorbing metamaterials are in detail introduced based on the multiresonanceintegrated absorbing structure, metamaterial absorbing structure combined with traditional material, threedimensional array absorbing structure, as well as spoof surface plasmon polaritons absorbing structure. Furthermore, the paper looks forward to the future of the broadband radar absorbing meta-material.

Abstract:In view of the limitation by the traditional methods in texture feature extraction and local motion perception, and referred to the powerful information processing mechanism of human visual system, a primary visual cortex（V1）vision percention model based on 3D spatiotemporal motion energy model is proposed. Firstly, simple cell receptive field is simulated by using 3D Gabor filter, then by half wave rectification operation, and further simple cell model is obtained. Finally, the simple cell receptive field is integrated by energy model, so that complex cell model is simulated. The simulation results show that the model possess good performance at extracting static texture feature of images and the local motion feature of simple video sequences. Compared with the traditional model, the model combines computer vision well with biovision, having stronger abilities at feature representation and extraction, and showing more powerful information processing mechanism of V1 cells. And this also provides new ideas for braininspired visual computing.

Abstract:To solve the problem of too large angle estimation error for radar under low altitude condition, a DOA estimation algorithm for low altitude target based on TR MIMO radar is proposed. Firstly, The focusing performance of TR technology is used in the proposed algorithm, obtaining the echo signal matrix. According to the waveform diversity of MIMO radar, The virtual subarrays of TR MIMO radar is deduced. Then, we perform rows and columns reuse and apply FBSS algorithm to remove the coherence, effectively improving the DOA estimation accuracy for low altitude target. The simulation results verify the validity of the method. The simulation results show that the RMSE of the proposed algorithm is reduced by an average of 0.3 degree compared with the conventional MIMO radar when the SNR is -10 dB.

Abstract:Aimed at the problems that in radar operation modes recognition, the errors measured of radar signal parameters of reconnaissance equipment seriously affect recognition effect, a timedomain fuzzy decision fusion (TFDF) recognition algorithm is proposed. Firstly, the characteristics of radar pulse group are analyzed and radar signal pulse group description (PGDW) words at the level of pulse group are extracted. Then, the traditional hard decision of neural network is improved based on the combined membership function, realizing fuzzy decision of radar signal. Finally, the DS evidence theory is used to fuse the fuzzy decision results of multiple moments in time domain, so as to complete the radar operation modes final recognition. The influence of recognition effect because of parameters measure error in radar operation modes recognition is improved based on the method timedomain fuzzy decision fusion. The simulation results and contrast experiment show that the method is good at antinoise performance, 90 percent of the recognition accuracy remains when the parameter errors of measurement are 15%.

Abstract:This paper proposes a joint estimation of target parameters for bistatic MIMO radar based on parallel factor analysis under spatiotemporal nonuniform sampling. Firstly, the covariance matrix of the Klevel nonuniform delays output data is calculated and transformed, and the redundant items of this matrix are deleted. Then, the new matrix is transformed to a thirdorder tensor and its dimension is reduced. Lastly, the Direction of Departure (DOD), Direction of Arrival (DOA) and Doppler frequency are estimated through Alternate Least Square (ALS) and RootMUSIC algorithms. The secondary expansion of the aperture degree of freedom both in time and space domain is attained by the proposed method. And the parameter estimation accuracy is improved while the amount of computation is reduced. Besides, the aperture is efficiently expanded and the system configuration requirements are reduced through the minimum redundancy configuration. The result shows that the proposed method is valid.

Abstract:Detection is one of the important tasks in image processing. How to improve the accuracy of object location is a difficult problem in the process of detection. On the basis of the SSD algorithm, this paper proposes a rough location and object class combined with selective search algorithm. Then, the paper searches the area of object by using an improved selective search algorithm to generate an object candidate frame. Finally, the paper adopts a boundary judgment method to obtain the accurate position of object and complete the detection from coarse to fine. In this paper, a lot of experiments are carried out based on 22531 images of PASCAL VOC data sets. The results show that the algorithm has a location error of 7.6 centers and a mean coverage rate of 90.8%. Compared with the other algorithms, this algorithm has lower center location error and higher coverage rate, improving the location accuracy of object detection by 20%~30%.

Abstract:In view of SIMO model, an adaptive MMSE blind equalization algorithm is proposed based on the nonzero delay equalizer. The method, through the relationships between the equalizer coefficients, the Variance matrices and the signal subspaces, is to extend the zerodelay equalizer to a nonzero delay equalizer. This method is different from the traditional zerodelay equalization algorithm, and can be utilized by the channels multilevel parameters for performing blind equalization to reduce the influence of the firstorder parameters of the channel on the equalization effect, and has robust to the overestimation of the channel order. In order to better adapt to the general timevarying channel environment and realize the realtime processing requirements, this paper presents a fast implementation of the algorithm by FDPM through recursive iteration. The simulation experiments show that the algorithm still has a good Mean Square Error (MSE) performance even if the signaltonoise ratio is low under the condition that the firstorder energy of the channel is small or the channel order is overestimated. In addition, the adaptive algorithm can quickly converge within a few hundred sample values.

Abstract:For convenience of studying the performance of the maximal ratio combining (MRC) diversity system under condition of non-identically distributed (i.n.d.) Nakagami-m fading channels, both the exact solution of the system outage probability and a method for obtaining the numerical solution of the outage probability are concluded based on the probability density function of the output signal to noise ratio (SNR). In accordance with the moment generation function (MGF) of the output SNR, the expressions of Chernoff upper bound of the average symbol error rate (ASER), the asymptotic diversity gain and the effective diversity gain under different modulation methods are obtained, and the correctness is verified by simulation. The simulation results indicate that with the increase of the number of diversity branches, the systems average symbol error rate decreases, and the diversity gain is enhanced. Simultaneously, the degree of fading unbalance for each branch has a greater impact on the system performance. Besides, the smaller the degree of channel fading, the greater its impact on the outage probability.

Abstract:Aimed at the problem that topology updating is fast in construction and network communication is low in efficiency in drone cluster networking, a clustering algorithm MPC based on mobile prediction is proposed. On the basis of this, a new clustering routing protocol MPCR is proposed. At the base of the grayWNN joint forecasting model, the mobile state movement factor is obtained by applying the prediction results to the direction, speed, and position evaluation factors. The clustering algorithm selects cluster heads by calculating the mobility factor and link retention time comprehensively. Passive routing discovery mechanism between clusters and active routing discovery mechanism between cluster members are used by the routing protocol for decreasing routing overhead. This paper verifies the prediction accuracy, the clustering algorithm, and the routing protocol through the simulation. The results shows that WNN improves forecast accuracy and packet delivery rate by 3 to 4 percentage points. And the clustering algorithm extends the cluster head holding time and the average link holding time, improving the clustering stability. The corresponding routing protocol reduces the endtoend delay, compared with other same protocols, and increases packet delivery ratio of packets, improving the routing performance.

Abstract:The preparation technology of BST thin film, electrode preparation, microstructure fabrication and terahertz band measurement method of BST thin film devices are systematically studied. The optimum preparation process of BST thin films is obtained by XRD, AFM and SEM. The electrically tunable frequency selective surface (FSS) in terahertz band is fabricated by electrode fabrication and microstructure fabrication of BSTbased thin film devices. Under condition of the action in electric field, the passband frequency is adjusted from 0.85 THz to 0.87 THz, proving the tuneability of BST thin films in THz band，and the method to determine the dielectric parameters of ferroelectric thin films in THz band is given. The related research can be used to accurately measure the dielectric properties of ferroelectric thin films in THz band, and provide accurate dielectric parameters for the development of functional devices of ferroelectric thin films.

Abstract:Aimed at the features that the emergent behavior is widely used and the occurred reasons are complex, a method of group emergent control based on data mining and fuzzy logic is proposed. Firstly, based on the traditional Swarm model, the dynamic data of agents under different parameters are obtained by traversing eight parameters influenced on the occurrence of emergent behavior. Meanwhile, linear regression and central clustering algorithm are used to recognize the type of emergent behavior under different parameters, and obtain the corresponding parameters of linear and circular emergent behavior. Then, the C4.5 algorithm is applied to precise parameters’ value range. Finally, the control of the occurrence of circular and linear multi-agent emergent behavior is realized by the fuzzy logic method. The effectiveness of the proposed control method is verified by simulation.

Abstract:This paper presents and realizes a digital filtering method for odometersignal based on state machine. The method, taking field programmable gate array as hardware，detects and filters burr of the odometer signal after resistanceCapacitance circuits and optical coupler, analyzes the causes of bring on metastable state when odometer signal is in fluctuation, gives out a design and implementation of filtering state machine and the method treating with the anomaly state caused by metastable state. The simulation results show that the method can filter out disturbance signal effectively and the counting number of odometer signal is accurate, and this is feasible in engineering.