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2003 Vol. 29, No. 4

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Analysis of Operation Effectiveness of ARM in Antagonizing AirDefense System
Ma Dongli, Zheng Mingqiang, Xia Haiting
2003, 29(4): 283-286.
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Operation effectiveness of aircrafts with anti-radiation missiles (ARM) in antagonizing SAM air defense system is studied. The maximum number and average number of penetrating aircrafts possibly shot by SAM missiles are given. Through an analysis of the lead speed character of ARM, methods of calculating the probability that the radar of SAM is killed by one aircraft and the probability that an aircraft is killed in the phase of attack are presented, the killed number of a group of aircrafts is also given. Requirements for ARM design are finally presented.
Solution of Tridiagonal Banded Linear Equation Setwith Diagonal Points Based on QR Decomposition
Wang Ganglin, Wu Zhe
2003, 29(4): 287-290.
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A characteristic linear equation set is a tridiagonal banded linear equation set with two diagonal points. Generally, it is very difficult to solve the equation set perfectly with methods of linear algebra. Different from the algebra based on LU decomposition and iterative algebra, author brings forward and discusses a solution of the equation set through QR decomposition. QR decomposition is ubiquitous but used few, because of its vast amount of computation. Tridiagonal banded linear equation set with two diagonal points has its characteristic, so QR decomposition can be used to solve the linear equation set with satisfactory precision and economic amount of computation. Analysis and examples are presented to show that the proposed algebra meets the requirements on precision and computation amount in application.
TT&C System Based on VR Technology for Unmanned Helicopter
Zhao Gang, Zhang Xiaolin
2003, 29(4): 291-294.
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By introducing VR technology and designing a high speed telemetry data filter algorithm, a high performance long-distance real-time unmanned helicopter TT&C system was constructed. This system possesses advantage in real-time reliability and visualizing of telemetry data.
On the Distribution of Stress in Blood Vessel Wall
Wang Shoumei, Xu Ming
2003, 29(4): 295-298.
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Mechanical stress has long been hypothesized as one of the important factors in regulating the structure and organization of vascular smooth muscle cells. Based on the conceptions of zero stress state and opening angle proposed by earlier researchers, stress distribution in blood vessel wall with inner pressure was investigated numerically. The results indicated that opening angle has a strong effect on the distribution of circumferential stress in the thickness direction of the vessel wall.
Method for Calculating the Dynamic Path Error of NC Machine Tools Based on MATLAB
Huan Ji, Ma Weimin
2003, 29(4): 299-302.
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The sources of dynamic path error of NC machine tools during milling process are analyzed, a simulating method based on MATLAB is introduced. The simulating modules and calculating methods of some typical 2-axises and 4-axises tracks at different feed speeds are also described. The simulating results show that, during high speed milling process, the dynamic path error of NC machine tools cannot be neglected.
Indirect Adaptive Control Based on Hierarchical Fuzzy Systems
Sun Duoqing, Huo Wei
2003, 29(4): 303-307.
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In order to solve the problem that the number of rules in a (standard) fuzzy controller increases exponentially with the number of variables involved, an indirect adaptive control scheme for a class of nonlinear systems was proposed based on hierarchical fuzzy systems. It was proved that the proposed scheme can not only guarantee the uniformly ultimate boundedness of the closed-loop system, but also makes the tracking error converge to the origin or its small neighbourhood. Simulation results on controlling an inverted pendulum verified the efficiency of the hierarchical adaptive fuzzy controller.
Optimization of Extended Kalman Filter for Cellular Mobile Location
Shi Yanshan, Li Daoben, Fan Yuezu
2003, 29(4): 308-311.
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An extended Kalman filtering (EKF) algorithm is designed for radiolocation in cellular communication system, simulation is conducted to examine its performance. An improvement of the algorithm is then made, using predicative error obtained by variance of time of arrival (TOA) measures and the linear relation between the measurement and the state vectors revealed by the simulation results. The predicative error is used to adjust the estimation of mobile position achieved by the fore EKF algorithm. Finally, the location accuracy obtained from the improved EKF shows better performance than the fore one in simulations, even in the case of non light of sight (NLOS).
Theoretical Research on Software Reliability Testing Adequacy
Li Qiuying, Lu Minyan, Ruan Lian
2003, 29(4): 312-316.
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Based on the significance of research on software reliability testing adequacy,the concept, the classification and the relationship of software reliability testing adequacy criterion with the whole software testing adequacy criteria system are presented. A method of how to use the relationship in software reliability testing practice is proposed. An initial research on software reliability testing adequacy based on previous theories about software testing adequacy is conducted.
On the Vibration of Stator of Linear TravelingWave USM
Ji Yuan, Li Hua, Zhang Deyuan
2003, 29(4): 317-320.
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Semi-infinite slender beams were analyzed with the theory of elastodynamics, conditions for large amplitude of slender beams were calculated. Based on the conditions, a linear traveling-wave Ultrasonic Motor(USM) was developed. Vibration of the stator of USM was analyzed based on consideration of traveling-wave reflection. With the help of simulation, it was shown that the reflectedwave exhibits a great influence on drive characteristics of USM. A series of experiments proved the validity of the conclusions.
Direct Numerical Simulation of Coherent Structures in a Boundary Layerwith Steady Pressure Gradients
Li Zhaorui, Lu Lipeng, Zhang Qiang
2003, 29(4): 321-326.
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By using the method of direct numerical simulation(DNS), evolution of coherent structures in the wall region of a turbulent boundary layer with three different pressure gradients was studied. Initial values of the coherent structures in the wall region were obtained on the basis of the idea of resonant triad in the theory of hydrodynamic stability. It was found that the results of DNS match with those of the experiments very well in many aspects. The effects of pressure gradient on coherent structure were obtained by comparing the results of three different cases.
Application of Diakoptics Arithmetic to RF and Microwave Circuit Design
Li Mei, Su Donglin, Yang Zhengguang
2003, 29(4): 327-330.
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It is very important to choose proper time domain modes when microwave structures are analyzed by time domain Diakoptics. Efforts were made to find out the proper time domain modes for analyzing open microwave structures. Based on analysis of electromagnetic field distributions for such open microwave structures as conductor-backed slotline, conductor-backed coplanar waveguide, microstrip line and coplanar strips, the zero and one order Bessel functions were proved to be the proper time domain mode functions. The rules of choosing time domain modes for these open microwave structures were summarized. The results can provide useful references for further investigations in this field.
Design of a TwelveChannel Digtal GPS Simulation System
Lu Juan, Chang Qing, Zhang Qishan, Zhang Jun
2003, 29(4): 331-334.
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For the purpose of testing the performance of GPS receivers, a GPS signal simulator is needed that can emulate the real GPS signals under all kinds of conditions. Single channel and multi-channel GPS signals' characters in time domain and frequency domain are analyed. A mathematic model of the twelve-channel GPS simulator is proposed. In order to reduce the difficulties of the hardware design, this model is designed to provide a 35.42MHz IF signal directly by applying the idea of "software radio" and the theory of interpolation. Simulation results with SystemView software have demonstrated the feasibility of the system scheme. In addition, a practical hardware design of this system is described.
High Order Entropy Condition Scheme for Mixed Euler/N-S Equations
Li Jingjing, Li Chunxuan, Dong Haitao
2003, 29(4): 335-338.
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In order to circumvent the problem of a huge amount of computing time required for solving viscous flows over bodies with complicated configuration using N-S equations, a mixed Euler/N-S solver was proposed. The solver is capable of preserving sufficient accuracy by using N-S equations in the flow field where viscous effects emerge as the dominant factor and employing Euler equations in the remaining regions. The primary scheme was constructed based on a high order entropy condition algorithm, in conjunction with an operator splitting concept deduced from theory of semi-group. The developed method was usedto simulate subsonic, transonic as well as supersonic flows over a mortar configuration. The numerical results were compared favorably with experimental data.
Analysis of Kinematics of Delta Parallel Micromanipulator with Vector Space Method
Bi Shusheng, Zong Guanghua
2003, 29(4): 339-341.
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Delta parallel mechanism has been applied in the domain of micromanipulation since it contains only revolute joints. Kinematics of 3DOF translational parallel micromanipulator is analyzed with a vector space method. Based on Jacobian matrix,the forward and inverse kinematic singular configuration of the Delta parallel micromanipulator is also studied. The results show that sensitivity parameters existed in Jacobian matrix affect the relation between the input and the output of the micromanipulator, the vector space method is simple and convenient in analyzing the singularity of parallel mechanisms.
Extraction of Linear Features of SAR Images Based on Fuzzy and Least Square
Wang Yanli, Chen Zhe
2003, 29(4): 342-345.
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A linear feature extraction method is proposed for SAR image. Firstly, the speckle noise in the radar image is filtered out. Secondly, the SAR image is processed by fuzzy transition and enhancement. Then, the low-pass and high-pass filters are designed by the least squares methods and the gradient strength map and direction map are acquired. Lastly, the gradient profile maximum method is adopted to detect feature points, which are connected to form the linear feature map of the SAR image. Simulation results show that the proposed method has the characteristic of anti-noise, the precision of positioning can reach 1 pixel.
Experimental Research of Low Speed Aerodynamic Characteristics ofSaucerLike Lifting Body
Wang Jindong, Shen Xialing
2003, 29(4): 346-349.
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Wind tunnel experiments of a saucer-like low speed lifting-body were conducted, for the purpose of improving its low speed aerodynamic performance and investigating effects of various aerodynamic factors. Aerodynamic coefficients were measured in the wind tunnel experiments, some different methods of boundary layer control were compared and their characters were described. These results showed that combined with proper aerodynamic design and boundary layer control, the performance of the saucer-like low speed lifting-body can be improved significantly. The highest lift to drag radio is up to 18.7, 86% improvement relativeto its prototype, with the zero-lift drag coefficient being decreased 56%. With boundary layer control instruments, aerodynamic performance at high angle of attack is also improved. Experiments approved that this saucer-like lifting-body takes the advantage of less outer size and higher carrying capacity, and test flight of its radio control flight model has been accomplished successfully.
MovingPolynomial Smoother Algorithm for Telemetry FlightTest Data Processing of Pilotless Helicopter
Zheng Yi, Zhang Xiaolin
2003, 29(4): 350-353.
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Method of filtering and smoothing of the telemetry flight-test data post-processing of no-driver helicopter is discussed here. An optimal linear polynomial filter with white noise moving-polynomial algorithm is proposed to estimate the true values from telemetry signals with random noise. The degree of compression for the random error is provided by the variance ratio of filtering. The algorithm was used to post-process some actual flight test data and the results confirmed the adaptability and effectiveness of this method.
Bayesian Method for Fault Diagnosis of Equipment at Lot Assure Tests
Huang Zhigang, Chen Xiaofang, Liu Zhongkan
2003, 29(4): 354-357.
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To resolve the problem of low locating rate in fault diagnosis, efforts were made by using preceding fault information fully in lot assure tests. By studying the failure rules of air-bone radio equipment in lot assure tests, the fault probability under extreme-small-sample conditions was estimated using Bayesian method. An approach for direct fault detecting in next step was established by using the fault probabilities of different modules. Three methods of direction were adopted to simulate those probabilities, the results showed that the strategy of the present paper can effectively improve the rate of locating faults in only one detecting progress and reduce fault finding time.
SuperManeuverable Combat DecisionMaking and Simulation for a Fighter
Ye Maolin, Shen Gongzhang
2003, 29(4): 358-361.
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It is important for fighter to have good maneuver ability in air combat. A model for super-maneuverable air combat decision-making was presented based on some basic flight motions of maneuver. Several typical super-maneuverable combat simulations were conducted with an integrated flight/fire/ propulsion distributed computer real-time simulation control system, using nonlinear robust flight control laws. The simulation results showed that the super-maneuverable fighter achieved a great benefit in air combat.
Dept. of Computer Science and Engineering, Beijing University of Aeronautics and Astronautics
Lin Xuelian, Liu Xudong, Huai Jinpeng
2003, 29(4): 362-365.
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The eXtensible Markup Language (XML) is going to be the common data language of distributed computing. With the broad application of XML, especially in electronic commerce, its security becomes one of the key topics of concern. The particularity of XML security was examined. A security system based on XML digital signature and XML encryption technologies was designed and implemented. The system was proved to be universal, reliable and extensible, meeting the requirements of XML security.
Development of Antenna Tracking System for Pilotless Helicopter
Jin Shi, Zhang Xiaolin, Ma Wenzhi
2003, 29(4): 366-369.
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To make sure that the antenna points to the right direction is the basis of effective work of telemetry and telecommand system of a helicopter. The accuracy, reliability and tracking mode of an antenna tracking system are discussed, and specific problems associated with its application to the helicopter are solved. Comparing with normal angular tracking system, this system is demonstrated to be simple, effective, reliability, low cost and feasible for mobile base station. Now this system is going to be put into practical use.
Gauss Numerical Integration in Nonlinear Analysis of Reinforced ConcreteMembers under Eccentric Compression Loading
Jiao Junting, Ye Yinghua, Diao Bo
2003, 29(4): 370-373.
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Secant stiffness matrix and tangent stiffness matrix of reinforced concrete arbitrary cross-section members with eccentric compression load are derived, on the base of plane assumption and the cross-section equilibrium equations. The secant stiffness with tangent stiffness of reinforced concrete are gained by adding the secant stiffness matrixes with tangent stiffness matrixes of the triangles, which are calculated by using Gauss numerical integration method on the devided triangles of the concrete section area. The cross-section complete path nonlinear analysis of reinforced concrete arbitrary cross-section members is traced. The results agree very well with the data of the references and test data.
Optimal Method of Temperature Demodulation in DistributedFiber Temperature Sensor Based on Raman Rejection
Su Guobin, Li Zheng
2003, 29(4): 374-376.
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Raman back-scattering of distributed fiber temperature sensor is very weak, stokes and anti-stokes are colored by noise after O/E convertion and amplifying. This paper presents the optimal method of temperature demodulation in distributed fiber temperature sensor based on Raman rejection, in which stokes and anti-stokes data are colored by gauss noise. An optimal split ratio is obtained which can minimize the error of temperature measurement.

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