DONG Xin-min , XU Yue-jian,CHEN Bo
2008(6):1-5.
Abstract:Automatic aerial refueling (AAR) is the advanced form of aerial refueling, its application can greatly extend the efficiency of unmanned aerial vehicles. And it has been a new research area of aeronautics in recent years. In this paper, a comprehensive review is made of state of art research in automated aerial refueling. By introducing the characteristic of AAR, the two existing methods of aerial refueling are compared with each other. The basic principles and technical approaches are discussed in detail. Three parts such as selection of sensor, controller design, simulation and testing, are particularly discussed to introduce the up to the minute investigation. Some important topics, including the sensor precision, maneuver rendezvous and docking strategy, cooperated operation, command and communication, and navigation algorithm are put forward as the fundamental problems and technical challenges in future aerial refueling research. Finally, the technologies which could be exploited primarily and come true in near future is pointed out.
FANG Shao-qiang , WEI Ke , CHEN Wei-peng , ZHAO Shang-hong,WU Ji-li
2008(6):6-10.
Abstract:The vehicle schedule model in flight supporting process is established, and an optimized algorithm of vehicle resource arrangement based on Tabu Search algorithm is proposed. The simulation model and the optimized algorithm are integrated through built-in VBA technique and VBA block of Arena, which makes up the vehicle schedule simulation-based optimization system. The simulation-based optimization system realized three functions: controlling simulation model, integrating optimization algorithm and inputting parameters into simulation model. Through this system, the optimum vehicle number arrangement under minimum single flight support time is obtained. The operation efficiency is increased by more than 7 times by using this system than by using the bound optimized tools OptQuest for Arena.
LIU Wen-fa , WANG Xu , MI Kang
2008(6):11-15.
Abstract:Navier-Stokes control equations and standard turbulence model are employed to numerically simulate the aerodynamic characteristics of forward-swept wing (FSW) and backward-swept wing (BSW). The superiorities and shortages are compared, and then the flow mechanism is analyzed by streamlines display. The research results show that the lift coefficient of BSW is higher in low angle of attack while the stall characteristics of FSW are better in big angle of attack owing to the opposite direction of the spanwise velocity. The premature wingtip stall induces lower angle of attack while stalling. The reason why FSW has better performances during big angle of attack is the favorable interference produced between vortices of side-strake and wingtip leading edge, which affords great vortex lift and enhances the control ability to the flow on the wing surface. The flow mechanism of the forward-swept wing can provide theoretical references for the design of the advanced aircraft configurations.
ZHAO Hui , HU Jie , HUANG Chang-qiang , WANG Zhi-jun , CUI Liang
2008(6):16-21.
Abstract:Based on the framework and standards provided by HLA (High Level Architecture), simulation method of UCAV (Uninhabited Combat Air Vehicle) was studied. The federation structure of the simulation system was introduced. FOM (Federation Object Model)/SOM (Simulation Object Model) and time management of the federation are designed. Three ways such as real-time RTI end-system、communication assurance system and enforced predictable RTI service are adopted to meet the real time requirements. Factors that affect cruise height are also analyzed, and the models of the factors are established. According to the simulation procedure, federation simulation platform is designed by adopting MK RTI and Visual C++6.0. The results obtained from the simulation on the cruise height of UCAV are believable and detailed. The simulation system prepared the ground for the simulation of the UCAV combat tasks and can be a reference for the future development of the similar system.
BAI Xiao-hui , LIU Bo , CHEN Yun-yong
2008(6):22-27.
Abstract:A three-dimensional flow field of a small radial-flow turbine has been investigated by two methods of numerical simulation in this paper. The characteristic curves and primary parameters of different rotation speeds have been obtained. Through comparison and analysis, the result shows that the characteristic curves calculated by the quasi-three-dimensional method and by the three-dimensional method are basically the same. The characteristic curve can be obtained by using the quasi-three-dimensional method which needs shorter time than by using the three-dimensional method. By analyzing the characteristics of the flow field of the three dimensional numerical simulation, the initiative knowledge of the flow rule inside the radial-flow turbine is obtained, which shows that the flow losses exist, in different degrees, nearby the leading edge and the trailing edge of the blade at the design point. The numerical simulation can be used in the improvement and redesign of the turbine.
BAI Yang ,LIANG Jun, ZHANG Qiang , XUE Guo-hong
2008(6):28-32.
Abstract:Because the evaporation of seawater and the onflow of the sea breeze, the atmospheric humidity dimension with altitude in range of offing, it makes Atmospheric Guide. The high speed data link of unmanned aerial vehicle(UAV)is affected badly by the multiple channels of atmospheric guide in sea navigating. The APM model is made for computing the transmittal loss, which shows that the energy fastens on the Atmospheric Guide, so strong branches and dispersion are caused. By combining the reality radar echo figures and the mechanism, the model of dispersion discrete multiple channels is given. The course of academic analysis and idiographic actualizing methods of the model are expatiated, which can provide an important theory basis for the measurement of the channel characteristic.
NI Shi-hong , LIU Min-zhi , XIA Yan , SU Chen
2008(6):33-37.
Abstract:The traditional SGA has the characters of converging early and obtaining easily local best result in the case of processing complicated optimizing problem. So the immune principle is brought in SGA and a new affinity definition strategy (affinity based on sine function) is put forward. This strategy restrains adaptability in the manner of approximate line prophase and flatness anaphase, and a sine based immune genetic algorithm (SIGA) is designed to improve its global and local searching abilities. The experiment results demonstrate that the convergent precision and speed of SIGA is better than those of SGA. Taking the engine stabilization for example, by applying the SIGA, picking up the aviation state classification rules is successfully realized. The testing results indicate that the rule acquired is simple and effective if the training sample is selected properly.
TONG Ning-ning , GUO Yi-duo , MEN Jian
2008(6):38-41.
Abstract:Aiming at the problems of multi-path sources in transmition and the active interference which might cause the coexistence of uncorrelated sources and coherent sources, an ordinal DOA estimation method is proposed under non-stationary noise field. The uncorrelated sources are firstly estimated by using the conventional spatial spectrum estimation method, then the noise is eliminated by the generalized differencing method and the uncorrelated sources are displaced by exploiting the property of oblique projection, so the only remained coherent sources can be renewed to full rank by the technique of the modified spatial smoothing algorithm. Compared with the traditional method, the number of sources resolved by this approach can exceed that of the array elements avoiding repeated estimation of the correlated sources. Simulation results demonstrate the effectiveness and correctness of the proposed method.
BAI Jian-lin , HUO Liang , LIU Peng , ZHANG Ping-ding
2008(6):42-46.
Abstract:In the air defense warfare under information-based condition, establishing detect & surveillance network is the technical guarantee of capturing informational preponderance.Meanwhile,realizing scientific and reasonable allocation of sensors resource is the important method of promoting the efficiency in gaining the air defense detect & surveillance network information. In order to make full use of the function and the performance of air defense detect & surveillance network, we have to allocate the limited sensors resource scientifically and reasonably in the phased-array radar network so as to improve the whole effectiveness of detect & surveillance network and furthermore to improve air defense warfare effectiveness. In view of the phased-array radar network multi-sensors resource management optimization problem, the phased-array radar characteristic and the network significance are introduced, and a relative entropy multi-sensors management algorithm based on phased-array radar network is proposed. By using this algorithm, each sensor to each goal greatest information content is obtained by calculating the sensor-to-goal indetermination of relative entropy, then taking this as the price function, the multi-sensors to the multi-goals optimized assignment is performed, and the simulation result indicates that this algorithm is valid and effective.
TANG Jian , SHI Hao-shan , YANG Qi , LI Xue-song
2008(6):47-51.
Abstract:Sensor network, which is made by the convergence of sensor, micro-electro-mechanism system and networks technologies, is a novel technology about acquiring and processing information. Wireless communication module is the most important component of the energy consumption on the WSN node boards, node identity is necessary in each communication with others. We consider the wireless sensor network (WSN) as a unknown anonymous network (UAN ) and analyze the disadvantage of assigning distinct identities which have been proposed to nodes of an UAN. The paper discusses the three phases of the identity assigning, then presents a new Layered Dynamic Identification Assigning (LDIA) algorithm for WSN, which is a distributed and energy efficient solution. The performance of the LDIA is verified under the NS2 simulation environment and in comparison with the DFS、0-1-Split 、L-P and W&L methods, and a number of experiments are performed under the NS2 Simulation Environment. The simulation results indicate that the proposed algorithm can satisfy the requirements for flexible deployment, low cost, high scalability and it is more effective.
WU Xiao-yan , YANG Li-na , ZHOU Yan-yan , GAO Zhong-chang
2008(6):52-56.
Abstract:Simulation Model Validation is one of the key content in modeling and simulation VV&A. The methods of simulation model validation include time domain, frequency domain and time - frequency analyses. Though the methods of time domain and frequency domain are used widely, the analytic means is considered single. However the methods of time - frequency analyses have particular advantage. The application of wavelet transform has been involved in many fields in recent years, for example, signal processing, pattern recognition and fault diagnosis etc. The paper attempted to apply wavelet transform to simulation model validation. The basic theory and property of multi-resolution analysis on wavelet transform are applied, based on the idea that the signal characteristic is described by using the wavelet transform coefficients. On the basis of multi- scale decomposition of wavelet transform, the output sequences of the simulation model and real system are divided into low frequency and high frequency parts,and the consistence test method based on the discrete wavelet transform coefficients is built according to their respective characteristics. The application example is given and the validity of the method proved.
WANG Rui , FU Ying , WANG Cheng
2008(6):57-61.
Abstract:In order to efficiently combine high conflict evidence and improve the reliability and rationality of the combining results when evidences are in high conflict, a new method of weighted evidence combination rule is proposed. In adopting this proposed approach, according to the associated characteristic between evidences, the weight of evidence in sensor system is acquired by calculating the relative distance in body of evidence. First, a distance function between the bodies of evidences is introduced.According to the bodies of evidences, the similar degree between the bodies of evidences from different sensors and the support degree of each evidence are gained.Then the reliability of each evidence can be got from the support degree, with this as the weight of each evidence in weight-averaging the basic probability assignment.Finally the fusion of the weight- averaged evidences is performed with the Dempster combination rule. Compared with the existing methods, the proposed approach is more efficient and rapid in recognizing the target when false evidence is in existence.
LONG Ge-nong , FENG Cun-qian , WU Fa-wen
2008(6):62-66.
Abstract:Aiming at the ubiquity of coherent sources in real circumstances, an ordinal algorithm to direction of arrival (DOA) estimation for symmetric uniform linear array is presented. under the condition of colored noise field.The algorithm combined with spatial differencing and Toeplitz reconstructing is used to cope with the situation where both uncorrelated sources and coherent sources exist, The uncorrelated sources is first estimated by using MUSIC, simultaneously the noise covariance matrix and uncorrelated sources are eliminated, Then a Toeplitz matrix is constructed for the remained coherent sources to renew full rank. After preprocessing, propagator method (PM) is employed to find the DOAs without any eigen decomposition. By using this approach, the number of sources resolved exceeds that of array elements and at the same time the computational complexity is obviously reduced. Simulation results show that the proposed method is effective and correct.
WANG Fei , WANG Jian-ye , ZHANG An-tang , ZHANG Lu-you
2008(6):67-70.
Abstract:To meet the application need of the separation of signal subspace and noise subspace in the MUSIC algorithm, this paper presents an improved Jacobi algorithm--parallel Jacobi algorithm, and gives a method of achieving the modification of data covariance matrix eigenvalue decomposition based on the Systolic Array structure. The vectoring mode CORDIC algorithm and rotation mode CORDIC algorithm are adopted to realize the Systolic Array structure. Fixed-point operation of 16 bit is selected by system finite bit-length. The whole matrix eigenvalue decomposition consumes 24 372 basic logic elements in FPGA, the maximum system frequency is 145 MHz, and the lowest time consumption in achieving once matrix eigenvalue decomposition is 14.82. The theory analysis and experiment validation show that this method is of high precision, and fast in speed, which greatly improves the real time property and enlarges the application scope of MUSIC algorithm.
ZHU Shi-huan , LI Yong-xin , BAI Lu
2008(6):71-74.
Abstract:In hausdorff Local convex topological spaces, this paper deals with the equivalence problem of two kinds of proper efficiency for set-valued vector optimization. The strong efficiency and strict efficiency play the important roles in optimization theory. At present it is known that the strict efficiency is equivalent to the strong efficiency under the condition of convexity. The nearly cone-subconvexlikeness of set-value maps is a very important generalized convexity in optimization theory, this note obtained the equivalence of strict efficiency and strong efficiency under the assumption of nearly cone-subconvexlikeness, and this conclusion is the generalization of the result that the strict efficient points equal to the strong efficient points for convex set. The results obtained in this paper will enrich the optimization theory.
ZHOU Chuang-Ming,DAI Wen-Yi, LEI Ying-Jie
2008(6):75-79.
Abstract:Compared with the common Fuzzy Sets, Intuitionist Fuzzy Sets (IFS) are good at describing the diversity and vagueness of the world, which has attracted many scholastics' attention. Extended from the Fuzzy Sets, Fuzzy Reasoning (FR) has been applied to many fields including vague control and artificial intelligence. However, it is explained that Intuitionist Fuzzy Reasoning (IFR) is more exquisite in finding out the inherent connections between the fuzzy objects. Originated by professor Wang, the Fuzzy Triple Implication (FTI) has deeply developed the theory of FR. Based on the above theories, and by researching on FTI, this paper extended FTI to Intuitionist Fuzzy Triple Implication (IFTI), and gave a dissertation about the necessity and strong point of it. Through proposing a new intuitionist fuzzy implication arithmetic operator, this paper solved the IFMP problem, and tested the argumentation by an example as well.
2008(6):80-84.
Abstract:By analyzing the problem of security and reliability existing in the traditional file system , this paper firstly proposes a security mechanism based on linux OS which means that the OS will be installed into a relatively independent space and separated with other software. Meantime, the phisical storage medium is only-read to make the OS un-rewritten. Users can install the software and save documents pellucidly in the user's space which is isolated with system space in phisical space. For the users, the views or the operation of the document system is as same as the traditional OS and the rock-bottom system space and user's space can not be felt. The principle of design and its practical details of space FS system are described particularly. Finally, the test data prove that the system is safe and reliable without performance loss.
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