Abstract:Multi-factor coupling flight situations have the characteristics of strong dynamic complexity and always leading to "irreversible" chain reaction disasters. To research the modeling and simulation method of pilot-aircraft complex system in coupling flight situations, the impact of disadvantageous factors on flight safety is analyzed, and the factor coupling types are classified. Pilot-aircraft basic model is set up based on non-linear six-degree-of-freedom mathematical model and pilot manipulation model. Special researches are conducted on the modeling of pilot failure model. The delay time failure is defined and modeled, and reverse manipulation model is established. The robot pilot reliability model, sensor general malfunction model and overload sensor malfunction model are established. The subject of "automatic pull-up using robot pilot in the lowest permitted height" in GJB 626A-2006 is used for example, in which the "human-machine" and "machine - machine" disadvantageous factor double coupling situations are simulated and analyzed to verify the feasibility and practicability of the method.

Abstract:This paper presents a strategy to deal with the issue of air-to-ground trajectory planning for Unmanned Combat Aerial Vehicle (UCAV) considering multi-restriction by using a Radau Pseudospectral Method (RPM). First, the paper establishes and analyzes a 3-DOF UCAV model and various complicated constraint models such as the preliminary and terminal position, speed, attitude, flying performance, enemy fire or detection threats, the no-fly zone terrain and so on, then, an air-to-ground trajectory planning for UCAV considering multi-restriction model is founded. After analyzing the basic principle that RPM solves the optimal control problems and how to implement it, the RPM is adopted to transform the optimal control problem for trajectory planning into a nonlinear planning problem. Finally, the problem is solved by using the SNOPT software package, and a numeric simulation is carried out. The simulation results show that the RPM can generate a continuous, viable and optimal trajectory satisfying various complicated constraints.

Abstract:Soil expedient runway usually is used in humanitarian succor，force projection，logistic sustainment and non-war military operations. Based on the summarization of soil expedient runway structure design criteria research of US Army corps of engineers, a design method based on support aircraft, coverage, and CBR is introduced in this paper. Finally, an example for the design is showed on ×× aircraft, the result is simple, reliable and of some important value for the future research of expedient soil runway.

Abstract:Fighter attack track following is the key of realizing fighter auto attack. This paper firstly analyzes the process of the fighter attack track following, taking the fighter sight error into attack track following algorithm, and proposes a method of fighter attack track following based on sight error. By dividing the sight error into two faces for analysis, the model of track following is built up. And by using Simulink toolbox and FlightGear, the process of track following is simulated comprehensively. The result shows that sight error will be reduced continuously to realize accurate flight following the tracks of attack .

Abstract:One of the key factors of the air-based boost-phase TBM defense is the interceptor speed. Based on the analysis of both the interception process and the boost-phase TBM characters, an interceptor speed requirement model is established. According to the average speed model, the factors influencing the interceptor speed can be divided into two major kinds: the changeable and the unchangeable factors. Lastly, a quantitative analysis of the influence of different factors on the average speed is made. The conclusion of the research can provide a quantitative basis for the feasible analysis of air-based boost-phase TBM defense and the requirement demonstration of interceptor.

Abstract:In this article,a miniaturized band-stop filter based the dual composite right/left-handed(DCRLH)[CM)]cell is proposed. Through the theoretical analysis of the equivalent circuit model of DCRLH, it is demonstrated that the right and left-handed pass-bands of DCRLH cannot be integrated even in the balanced condition and thus DCRLH cell exhibits inherently band-stop property. Through parametric scanning analysis, it is found that the band-stop property is quite excellent in the quasi-balanced condition. Based on the above results of the investigation, a band-stop filter is designed and fabricated further. The performance of the proposed band-stop filter is rather satisfactory. Simultaneously, its effective area is quite compact, because only one DCRLH cell is utilized. Both the simulated and measured results verify that the proposed design method is effective.

Abstract:In order to evaluate the weapon system effectiveness, American Weapon System Effectiveness Industry Advisory Committee advanced the ADC model. The model enhances the system integrity of weapons' structure, technical feature and tactical function. The defect of the traditional ADC model lies in the complex calculation procedure. Also, the evaluation is only confined to the basic effectiveness. The effectiveness of weapon system based on the conflict circumstance in reality can't be evaluated. This paper, based on the traditional ADC model, puts forward a simplified algorithm by referencing the thought of Markov process and establishes an improved ADC model by which the conflict circumstance is overall considered in reality to make the qualitative problem quantized. A real case is analyzed to confirm the effectiveness and scientificness of the new model. The paper shows particular concerns about the target missiles defense penetration ability, which is of some reference value to the weapons' conceptualization, initiation and design.

Abstract:By investigating military operation, an approach to developing Unit Ontology, Equipment Ontology, Task Ontology and Simulation Scenario Ontology is proposed based on OWL. Then the concepts related to combat and the relations between the concepts are inferred and checked by reasoning based on description logic, and the hierarchy of concepts is optimized. In order to illustrate the feasibility of developed ontologies, analyses of three applicable demonstrations are presented and verified. The results show that this method achieves logically classifying for military domain concepts and intelligently checking for scenario data, and automatically supports developer in decision-making for scenario development.

Abstract:A novel compact Single-Feed Dual-Frequency Patch Antenna is proposed in this paper. According to the analyses of characteristics of two operation bands, monolayer micro-strip-fed and slot-rectangle frame are adopted and separately printed on the opposite side of substrate in this antenna. The area of this antenna is only 20×26 mm. The operation bands of the antenna are from 2.40 GHz to 2.53 GHz and from 5.00 GHz to 5.96 GHz. Simultaneously the parameters that affect the operation frequencies are analyzed and studied by using EM simulation software HFSS10. Lastly, the antenna is fabricated and measured, and the measured results are in good agreement with the simulated results. The antenna proposed in this paper has the characteristics of miniaturization and dual-band, so it is suited for wireless communication field.

Abstract:Remote field eddy current (RFEC) technique has been widely used for the inspection of ferromagnetic pipes and it's not restricted by the skin-depth effect. However, the technique under the sinusoidal excitation needs a long probe and a high power dissipation, which restricts the application of RFEC in real inspection. The pulse exciting signal has the advantages of rich frequency components, the disadvantages of the traditional RFEC can be overcome by using pulse excitation instead of sinusoidal excitation. On the basis of analyzing the principle of pulsed RFEC, the distributions of the magnetic field and eddy current around the pipeline and exciting coil are simulated and analyzed, the changing rule of transient state detecting signals in different field regions is studied and obtained with finite element simulation method, then, the remote field region is confirmed. The zero-crossing time and negative peak value are extracted as the eigenvectors for defect quantification. Finally, the performances of quantifying the axial defect length and depth by the pulsed RFEC are verified by performing an experiment, the result shows that this technique can be used to realize the quantitative estimation of the defect.

Abstract:Virtual terrain environments have been used widely, and high-resolution texture images are of the foundation for visualization. Huge amount of data caused by the improvements on image resolution leads to the restriction of reading and storage which can influence the visualization system, data compression is an efficient means for boosting the system performance. When an aircraft is flying through a mountainous terrain at a high speed and low altitude under the condition of poor visibility, the manipulator usually gets disoriented where danger is likely to happen. The virtual terrain environment can provide the manipulator with a broad vision of the visual three-dimension geographical environment which keeps the visualization of terrain under special conditions. Based on the wavelet coefficients after lifting scheme, we firstly take the advantages of energy concentration on low-frequency sub-bands and relativity between sub-bands, then organize those coefficients across sub-bands and vectorize them, and again use one of the texture compression algorithm-vector quantization coding-for coefficients compression. This scheme is propitious for the real-time requirement in flight because of the high compression ratio, non-symmetrical coding and fast decoding speed.

Abstract:Local movement and inaccurate motion vectors affect the accuracy of global motion estimation seriously. In order to solve this problem, a fast and robust global motion estimation algorithm is proposed in this paper. Firstly, block matching algorithm (BMA) is used to estimate motion vectors. Then the inaccurate motion vectors are excluded by gradient mean residual error method to improve the accuracy of estimated global motion field. Secondly, the initial global motion parameters are estimated using a 6-parameter affine model and they are iteratively refined by matching weighting method. Thus the most accurate global motion parameters can be obtained. Experimental results show that the proposed method is efficient and robust in terms of both computational complexity and accuracy.

Abstract:Considering the situation that the received signals magnitude is decreased and inter-carrier interference (ICI) is induced by the carrier frequency offsets (CFO), through establishing mathematical model, the analytical expression for the Bit Error Rate (BER), which is derived from Transform Domain communication system (TDCS), is obtained. Furthermore, the relationships between the BER and the correlated parameters are studied, as well as, the Signal Noise Ratio (SNR) loss. Finally, the analysis conclusions are verified by the simulation, the simulation result agrees well with the analysis conclusion. The quantitative analysis of the system performance caused by the frequency error of carrier is given. These researches illustrate that the frequency offset affect the BER performance seriously and there is error floor on the BER when the normalized frequency offset is more than 0.6.To keep the system work around, the normalized frequency offset has to be less than 0.05.

Abstract:Attribute reduction is a key problem in theoretical research of rough set. Aiming at the NP-hard problem of acquiring all decision reduction in decision table, the paper simplifies the problem to decision reduction computation in incremental object，The arithmetic of attribute reduction based on minimal disjunctive normal form is respectively offered on the basis of analyzing the characteristic and correlation of discernibility set in discernibility matrix, in which the decision discernibility matrix is optimized by ① omitting repeated contrast between the objects; ② transforming the row of the decision discernibility matrix to the equivalent set; ③ treating the equivalent set of the positive field as the other row of the decision discernibility matrix. The method offers a tool to uniformly acquire all decision reduction of consistent and inconsistent decision table. The example analysis shows this algorithm's feasibility and validity, which offers an effective way for attribute reduction.

Abstract:Taking that the slide block in planar six-bar linkage is at the minimum rate fluctuation in working stroke for the pursuit of goals, and taking the existence of the crank and good transmission property for constraint conditions, a mathematical model of optimal design is set up and optimization design calculation is done by the application of the constrained variable metric optimization algorithm to obtain the mechanism size parameters. In Solid-Works software the three-dimensional model of assembly for the mechanism is built, and by using COSMOS-Motion plug-ins the motion simulation is done to put out the kinematic animation video, lines and other sports information, which provide a visual way for the optimal design of planar linkage. Simultaneously the above can be used to test or to determine the mathematical model of the mechanism optimum design, the correctness and rationality of the program design and the calculation results, and also provide a reference for the simulation design of other mechanisms.

Abstract:Radio Frequency Identification is a kind of non-contact auto-identification technique when many electronic tags transmit their only tag identification code to the reader; there will be collision arising, thereby, the research on collision avoidance is necessary and urgent. With the purpose of decreasing the recognition delay, a Pre-Query Tree Algorithm is proposed through the way of decreasing the collision identification and idle time. In this algorithm, the Binary Query Tree Algorithm is replaced by the Quaternary Query Tree Algorithm to reduce the collision. Meanwhile the slotted Pre-Detection Signal Mechanism is used to eliminate the entire idle time. Combined with the Binary Query Tree Algorithm and the slotted Pre-Detection Signal Mechanism, the collision problem of Radio Frequency Identification (RFID) at the aspect of electronic tag identification is promoted and the number of unnecessary query command is reduced. The simulation results show that Pre-Query Tree Algorithm could reduce the collision, and the entire efficiency of FRID system is improved.

Abstract:Because of the rigorous working environment, Subsurface Material Degradation (SMD) occurs in the stratified metallic structures which are extensively employed in industries such as aerospace and energy fields. This directly influences the angle operation of crucial components in the large-scale complex apparatus. This paper investigates a new Lift-off Intersection Point (LOI) via theoretical study of Pulsed Eddy Current Testing (PECT). Following the analysis of the forward problem of the new LOI, a method for evaluation of SMD in stratified metallic structures is proposed. Through experiments the proposed method displays some advantages. By using it the sensitivity of PECT based on the new LOI to subsurface material degradation is higher than that of the traditional-LOI based PECT, which benefits the quantitative evaluation of subsurface material degradation occurred within the practical stratified metallic structures.