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2005 Vol. 31, No. 05

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Demand-oriented quality evaluation of common ammunitions
Song Zhidong, Li Yunhua
2005, 31(05): 485-488.
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In order to play a good role in increasing the impact of military requirement, change the quality conception of our weapon equipments based on accordance with the designs for production to fit military requirement, increase the level of quality of our common ammunitions, evaluating scientifically the quality of our common ammunitions is very important. The implement of foreign military requirement and the modern quality conception were analyzed. A point of demand-oriented quality evaluation of weapon equipments was presented. The effect of demand-oriented quality evaluation of weapon equipments was discussed. It alsodid research on demand-oriented quality evaluation model of weapon equipments. The quality evaluation model of weapon equipments was set up, which carries out the thought of fitting military requirement. Based on analyzing the character of our common ammunitions and military requirement of our common ammunitions, a system of quality evaluation criteria of common ammunitions was set up scientifically.
Multiplying nonlinear control in electrohydraulic complound system
Sun Weihua, Qiu Lihua, Qi Xiaoye, Wang Zhanlin
2005, 31(05): 489-493.
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A multiplying nonlinear model was built to the electro-hydraulic compound control of airborne actuation system. A new approach based on feedback linearization and receding horizon optimization was presented to the system. The relative degree was less than the order of the system, so nonlinear system was transformed into a linear subsystem and a part of nonlinear via feedback linearization. The zero dynamics was researched so that the stability of the control system was guaranteed. On-line adjustment based on receding horizon optimization to the global linear model had strong robustness to unmodelled dynamic as well to enhance dynamic response. A finite-time horizon linear quadratic optimal servo problem was formulated with penalty on time-derivative of the control input as well as the error of trajectory in the performance index. State feedback was employed to keep the whole system stability. Simulation results show that the approach can eliminate uncertainty and disturbance and increase robustness. The system has better dynamic performance.
Analysis of handover performance of mobile IPv6 and an implementation of its smooth handover framework
Kang Jianchu, Chen Yu
2005, 31(05): 494-498.
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IPv4-based networks are faced with many problems like the lack of IP address, less security, and so on, which have limited the development of Internet, therefore, it is important to study the techniques of IPv6, so as to promote the construction of the next generation of Internet. The problems of handover latency and lost packets of mobile IPv6 were discussed, in which, the three extension techniques in current mobile IPv6 protocols, namely as fast handover, smooth handover and hierarchical mobile IPv6, were firstly analyzed. And then, based on the IETF drafts, a framework with smooth handover technique was brought forward. In this framework, the handover process and the buffer management worked at different levels respectively, which would improve the expansion and portability of the application systems. This framework would be viewed as an effective method to transport reliably the real-time information of the application systems working in mobile IPv6 environment.
Novel nonlinear prediction algorithm for fast fading channel
Sun Jiancheng, Zhang Taiyi, Liu Feng
2005, 31(05): 499-503.
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Prediction of the rapidly fading mobile radio channel enables a number of capacity improving techniques such as the fast adaptive resource allocation or fast adaptive modulation. To predict the fast fading channel parameters, the embedding phase space was reconstructed by utilizing times delay techniques since the high dimension space possessed more information of system than the scalar time series, and a new nonlinear regression method: recurrent least squares support vector machines (RLS-SVM) was used to resolve the prediction problem in a high space. The fading envelope was well modeled as a Gauss bandlimited process which possessed special predictability properties and the predictability was also analyzed from point of view of nonlinear dynamics. Performance evaluation of the prediction algorithm was carried out with varied signal to noise rate on Rayleigh fading channels. The simulation result shows that the proposed algorithm is a good candidate for long range prediction of fading channel.
Fractal-based covariance function description and classification of natural texture images
Wang Hua, Wang Qi
2005, 31(05): 504-507.
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To deal with the problem of charactering and classifying natural textures in images, a technique was employed which is based onthe fractional Brownian motion model and its covariance function. The covariance function of fractional Brownian motion was proposed to estimate the Hurst coefficient and constant k which are used to character the natural textures. The feature set has ten feature vectors which are combined with both five features of two sub-texture image. Ten features were based on both the above average gray level image and the below average gray level image rather than based on the original image. Rely on the mean value of texture images, two sub-texture images were obtained. Five features were based on sub-texture image, the horizontal constant,the vertical constant, the 45°directional constant, the horizontal and vertical Hurst coefficient as the distance is 2. 16 natural textures from the Brodatz album were considered, and the classification results show the efficiency of the technique.
New star pattern recognition approach based on Hausdorff distance
Wang Guangjun, Fang Jiancheng
2005, 31(05): 508-511.
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A new star pattern recognition approach has been devoloped. Its based idea was first extraction the star pattern information, fitting together the information to a pending data set B, putting all star catalog information into a criterion data set A, then computing the relative Hausdorff distance of two sets, here a and b is a vector element of set A and set B. The star was recognised according to the minimum Hausdorff distance. The approach is different from the conventional star pattern recognition approach, which uses the starlight angle-distance method to get the position, it takes the most of the information of star dimensional configuration, therefore, the approach has strong robusticity for the disturbance of noise, distortion, and a few meteor. In the case of random noise,imaging distortion, and a few meteor disturbing, the half physics simulation experimential result indicates that the approach has good recognition effect.
Application of trigonometric series for rigid wakes analysis of rotor aerodynamics in hover
Chen Ming, Sun Junyong
2005, 31(05): 512-515.
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To describe the attachment vortex circulation distribution of blades, contacting blade element theory, trigonometric series was adopted and applied for the model of classical rotor vortex theory. Some studies have been done for the air-operated characteristic of single rotor and co-axial rotors in hover. The attachment vortex circulation distribution of blades which is continuous and smooth was obtained by rough computation. While it is applied to the formulas found in the page, the induced velocity of continuous distribution can be resolved. Then analysis was done for the complex interaction between the upper and lower rotor, and the condition of balance between the torque of upper and lower rotor was got. The comparison between calculation results and experiment records shows that the previous theory and method is applicable. There are two conclusions: One is that while collective pitch of lower-rotor is changed, sharp influence is brought to lower-rotor, but it is nearly no influence for upper-rotor, the other is that when torque of upper-rotor equals to lower-rotor', the collective pitch of lower rotor is greater 1° than upper-rotor'.
Optimum design of the strategy of antimissile’s penetration
Jiang Yuxian, Chen Jinghua
2005, 31(05): 516-519.
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An application of genetic algorithms in the optimum design of the strategy of antimissile’s penetration was studied. The integrated process of antimissile’s penetration was divided into several stages; the optimum design of the integrated probability of penetration was transferred into the optimum design of the conditional probability of penetration of each stage. By doing so, the complex process was simplified. The antimissle must maneuver to improve the probability of penetration. The parameters of maneuver of each stage vary within a wide range and influence the probability of penetration. Genetic algorithm was choosen to do the optimum design of the parameters of maneuver. The genetic algorithm was applied in each stage of the penetration, the best group of the parameters which results in the highest probability of each stage was figured out. And then the group of maneuver parameters that lead to the highest probability of the integrated process of antimissile’s penetration was obtained.
Application of genetic algorithm in high frequency 2-D scattering signatures analysis
Zheng Jun, Su Donglin
2005, 31(05): 520-523.
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To investigate the scattering features of radar target in high frequency, a joint time-frequency analysis method——the adaptive Gaussian basis representation (AGR) was introduced to simplify the 2-D scattering parameter model.To estimate the model parameters, Genetic algorithm (GA) was proposed. This method takes full advantage of GA’s inherent parallelism and solves the estimation problem of the equivalent scattering center.The simulation results show that this simplified 2-D scattering model may not only discriminate localized scattering centers of the radar target, but also present distributed scattering centers of definite length. In terms of the extraction of scattering features using this 2-D scattering model, and this method can estimate all parameters of scatteringcenters correctly on condition of no noise, at this time it has a good performance of estimating the position of initial scattering centers and eliminating the noise in the low signal to noise rate(SNR). The analysis using the above 2-D scattering model is correct and feasible.
Helicopter dynamic response to wind shear in forward flight
Hong Guanxin, Pang Jian
2005, 31(05): 524-528.
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In order to solve the problem of numerical simulation of the helicopter motion in wind shear and study the characteristics of the helicopter dynamic response to wind shear, one-dimensional and two-dimensional wind shear models were set up, nonlinear system mathematical model of helicopter flight dynamics was concerned with the consideration of the control system and Runge-Kutta method was used to simulate the forward flight. It shows that different wind gradients of longitudinal air velocity have different impacts on major parameters dynamic response of helicopter and every kind of wind gradients should not be neglected in different situations, particularly, in the situation involved here, the most dangerous environment comes from the integral two-dimensional wind shear model, and the impact on helicopter in the low-attitude flight should be noted. It also shows that this numerical simulation method works effectively in the study of dynamic response to complicated wind shear of helicopter nonlinear system mathematical model
Numercial simulation of transonic axial compressor rotor flow with tip clearance using multi-block meshes
Li Minjiang, Gui Xingmin
2005, 31(05): 529-534.
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To investigate the tip clearance flow in transonic compressor rotor, a 3D numerical simulation code was developed. The 3D flow fields of a transonic axial compressor, NASA Rotor 37, with considering the tip clearance were simulated using Reynolds-averaged Navier-Stokes equations with high Reynolds-Number k-ε turbulence model and wall function. A multi-block grid was used for the tip clearance domain of the rotor, which couples with the main flow without any tip clearance experiential models, as well as avoids reducing the tip clearance scale under the assumption of Vena convergence effects. The Navier-Stokes equations and turbulence equations were strongly coupled by staggered finite volume scheme in order to get more precise results. The 3D simulation results were compared with the experimental data. The mid-span flow structures are consistent with experimental result, as well as the slight different details exist in the tip and hub flow structures because of the eddy viscosity model and shock-wave.
Application of the hybrid BP/GA algorithm in simple integrated navigation system
Fan Yuezu, Zhang Yinan, Ma Haokai, Wen Xin
2005, 31(05): 535-538.
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Kalman filter is the most usual optimization filter with some limitation when applied in the integrated navigation system. Especially in simple global positioning system/ dead reckoning system (GPS/DRS ),the receiver and the inertial navigation units are low-cost and low-accuracy. To improve accuracy of the system, it must be focused on the advanced algorithm. To compensate the divergence of Kalman filter, a hybrid algorithm composed of back propagation (BP) neural net and genetic algorithm (GA) together with Kalman filter was applied in low-cost GPS/DRS integrated navigation system. This algorithm owns not only self-study ability and good real-time performance of neural net but also optimization assessment ability of Kalman filter, and even overcomes many flaws of neural net,such as slow convergence ,sensitivity about the study parameters and local extremums. The simulation result also proves that this algorithm is prior in precise and stability compared to usual Kalman filter, for example, the statistic analysis shows that the maximal error of latitude is reduced to a lower magnitude.
On reliability model of FC interconnections
Xu Yajun, Zhang Xiaolin, Xiong Huagang
2005, 31(05): 539-543.
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To solve calculable problem of the reliability of fibre channel (FC) interconnection, based on basic FC interconnection model, a task based analysis method of system reliability was proposed, a reliability model of FC interconnection system was developed and the matrix of system reliability was used to describe reliability model. To three basic topologies of FC: point-to-point, arbitrated loop and Fabric, expressions were directly defined by reliability model. Based on combination topology of FC, the bridge-port in reliability model was defined, a reliability model of combination topology with bridge-port was developed. To a combination topology of Fabirc and arbitrated loop, an illustration of modeling avionics of FC network was also presented. By analysing the influence of bridge-port in task route, it is showed that bridge-port influences reliability of FC interconnection system most. The reliability model of task based has a directive effect on both task division and topology selection in the phase of avionics system design.
Animating virtual human for maintenance simulation with mixing control
Lü Chuan, Xu Hongqiang, Ma Lin, Zhou Dong
2005, 31(05): 544-547.
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There are two driving modes used to control virtual human during the process of virtual maintenance simulation. One mode that is called immersion simulation is to use virtual reality device, and the other mode that is not immersion simulation is to use algorithm. The two methods have different limitation, so in order to create maintenance simulation efficiently, the method of mixing control and the structure of implement was presented. The system generates motion of virtual human mainly by algorithm while virtual reality device was also used partly to avoid some complicated algorithms, and the aim is to integrate the two driving modes efficiently in the process of virtual maintenance simulation. The mixing system structure were described and the transferring mechanism between algorithm control and virtual reality device control were presented. At the end a case was applied. On current conditions, the mixing control provides an effective tool for maintenance simulation.
Grey relational analysis of fuzzy comprehesive evaluation of air quality in manned spacecraft
Pang Liping, Wang Jun
2005, 31(05): 548-551.
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The habitation module in manned spacecraft is a closed-chamber, and its air quality is increasingly attached importance along with longer time missions because it greatly influences the health of crew. It is necessary to put forward a new evaluation method of air quality. Based on the grading fuzzy membership functions of the trace contaminant being bought forward, a grey relational analysis of fuzzy comprehesive evaluation was adopted to assess the air quality in manned spacecraft. In addition, the membership functions of fuzzy grade of some important trace contaminants were firstly proposed. This assessment method merges the merits of the fuzzy evaluation and the grey one. It less depends on distributing rule and can analyze the trend of development. It can present fuzzy comprehensive evaluation matrix and grey relational grade at the same time, therefore reflect well air quality status and trend in development. The analysis shows it can more reasonably reflect actual air quality in manned spacecraft, and be used to assess the working performance of the trace contaminant control system.
Stress relaxation of open-cell foamed plastics
Lu Zixing, Zhang Hui
2005, 31(05): 552-555.
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Open cell foamed plastics have better energy absorption characteristics and better cushioning properties so that they are extensively used in engineering areas. Thus, their visco-elastic behavior has attracted the most people attentions. Based on the Lederman model, the stress relaxation of open-cell foamedplastics was investigated by using the model of standard linear solid to consider the visco-elastic behavior of matrix. The effect of strain loading, structuralparameter and Poisson’s ratio on the stress relaxation curve of open-cell foamed plastics was discussed at the same time. The results show that the stress relaxation curves are not sensitive to Poisson’s ratio and the increase of strain loading or relative density will make the stress relaxation more significant. However, the ratio of initial and final value for stress response does not change with the increase of strain loading. All the above conclusions obtained are very important for overall understanding the mechanical behavior of open cell foamed plastics.
Optimized evaluation point designing for R&D project
Wang Jing, Xi Yang, Han Yong
2005, 31(05): 556-560.
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Having been widely adopted in the management of research and development (R&D) projects, concurrent engineering can largely shorten the time limits for projects, however, its risk is higher. A risk model of implementing concurrent engineering was built. The optimum decision point is exactly the intersection between the "risk versus technological-maturity" relation curve and the "time versus risk" relation curve, and the classification of risks in R&D projects was proposed. Setting valid evaluation point is effective to control and reduce the risks, and a method to identify the optimized evaluation points was designed. In the method, the risks of each task can be determined by technological risk factors, scheduling risk factors and parallel risk factors, and then the overall risk of the project can be determined by the summation of all the risk values. A numerical example was used to demonstrate that the overall risk of R&D projects can be effectively reduced through the optimized evaluation point designing.
Chirp Hartley, Chirp cosine and Chirp sine transforms
Bian Yong, Zhou Yinqing, Li Chunsheng
2005, 31(05): 561-565.
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The definitions of analog Chirp Hartley transform, analog Chirp cosine transform, and analog Chirp sine transform were given firstly. The definitions of discrete Chirp Hartley transform, discrete Chirp cosine transform, and discrete Chirp sine transform were given secondly. These transforms were used to estimate the parameters of real polynomial signal. The parameter estimation ability of two-order discrete Chirp Hartley transform, two-order discrete Chirp cosine transform, and two-order discrete Chirp sine transform were researched in detail. The three-order discrete Chirp Hartley transform was discussed briefly. In order to eliminate the spurious signal in the processing results of two-order discrete Chirp cosine transform and two-order discrete Chirp sine transform, a method that can eliminate spurious signal effectively and depress the sidelobe with a little more computation burden was presented. The computer simulations of two-order discrete Chirp Hartley transform, two-order discrete Chirp cosine transform, and two-order discrete Chirp sine transform were performed. The computer simulation of three-order discrete Chirp Hartley transform was performed. The computer simulations prove the validity of the analysis.
High precision interpolation algorithm for star pattern
Wang Guangjun, Fang Jiancheng
2005, 31(05): 566-569.
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To extract the star position and star magnitude, a new algorithm was developed. The algorithm regards the star imaging pattern as Gauss point spread function model. The coefficient of Gauss curved face function was getted using the combination of linearity interpolation method and least squares method. From the Gauss curved face function, the sub-pixel position of star and its star magnitude were obtained. Theoretical research indicates that the extracted precision using Gauss curved method is higher than using traditional centroid method. The calculation of the direct Gauss curved interpolation is very complex, for reducing calculation, the x, y direction nonlinear interpolation method was used in imaging point adjacent, and the different coefficients of Gauss curved was getted individually. The simulative calculation results show that the locating precision less than 1/20 pixel and error of star magnitude less than 5% when the signal-to-noise ratio is 0.05.
Visualized expansion of managed objects in dynamically constructed network management
Yang Rui, Qian Depei, Luan Zhongzhi, Chen Heng
2005, 31(05): 570-573.
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Facing ever expanding of the Internet and the increasing number of applications on the network, the traditional network management is not able to satisfy the new demands on managing changing networks and applications. A new network management model——dynamically constructed network management was therefore proposed. In dynamically constructed network management system, the expansion of managed objects is an important component. A method for visualized expansion of managed objects was proposed. The visualization was achieved by generating a managed objects sets (MOS) tree on the manager interactive interface, and a set of graphical editing tools was supplied to help devices manufacturesand application developers to define their MOS modules visually. The generated MOS modules are of valid syntax format, and were submitted to the network management system. They are ready to be loaded into the management system by the dynamic MOS compiler. Then the association and expansion between managed objects and management functions were implemented through accessing those modules.
Dual-objective optimization design for cost and performance of a solid rocket motor
Yang Qing, Qiu Wanhua, Wang Liang
2005, 31(05): 574-577.
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To solve the problem of multiple attributes value optimization in the upper stage solid propellant rocket engines of a launch vehicle, parameter-cost models of motor parts were established and an improved pareto genetic algorithms(IPGA) that combines the NSGA-Ⅱ with local search algorithm was presented. Simulation test shows that the convergence of IPGA is better than that of NSGA-Ⅱ. Setting the maximum terminal speed increment of the rocket motor and its manufacture cost as objective functions, Pareto optimal sets were obtained by using IPGA which motor case materials are APMOC and carbon respectively. Adapting the deal point method, an inflexion point of cost- effect ratio in Pareto optimal setswas gained. Setting this point as trade-off solution, the calculation results show that the effective load of the launch vehicle was increased by 7.6% and cost of the motor was decreased.
Interconnection between BACnet and Internet
Fang Yi, Xiong Zhang, Wang Zhongxin
2005, 31(05): 578-582.
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The comparison and analysis of two current interconnection technologies between a data communication protocol for building automation and control network(BACnet) and Internet, including BACnet/internet protocol packet-assembler-disassembler(B/IP PAD) and BACnet/IP, was carried out. The existing questions of two technologies were pointed out. The interconnection model based on BACnet gateway was presented. The gateway works at BACnet network layer. The gateway need configure an isolated IP address and a BACnet network ID. The gateway must maintain a local database including IP addresses and BACnet network IDs of peer-to-peer gateways. The functions of BACnet gateway consist of semantic transformation, broadcast and management of different protocols. A uniform network interface between BACnet and Internet was provided by the model. The convergence capacity of the building control network and Internet was enhanced. The interconnection process between BACnet network and Internet was greatly simplified. Based on the research of the model’s architecture and workflow, the implementation approach of the model was discussed.
Enhanced mixing in 2D micro-channel electro-osmotic flows
Fang Li, Zhang Jinbai
2005, 31(05): 583-586.
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Micro electro-mechanical system (MEMS) elements are extremely small,soslow mixing due to low Reynolds number is the one of most significant performance limitations for micro-fluidic systems.The present work is a numerical study of the electro-osmotic flows (EOF) in micro-channel with non-uniform wall zeta potential. In particular, the mixing enhancements of micro-channel flow were investigated, which are due to induced transverse flows resulting from the variations in the wall zeta potential. Based on the Helmholtz-Smoluchowski wall slip velocity model for EOF, four cases of electro-osmotic flows in micro-channel with non-uniform wall slip velocitys and the mixing of the passive scale in these flows were computed with the semi-implicit method for pressure-linked equations (SIMPLE) algorithm. The results show that the non-uniform wall slip velocitys induce zigzag streamlines, and as a result, the mixing are enhanced. In generally, the mixing efficiency increases with the strength of the transverse flows.
Decentralized robust reliable H∞ control of uncertain interconnected systems with delays in subsystems interconnection
Li Tong, Jia Yingmin
2005, 31(05): 587-591.
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Two kinds of typical problems frequently encountered in the control engineering were investigated, i.e. parameter uncertainty and control component failure. For a class of discrete-time uncertain interconnected systems with delays in subsystems interconnection, a linear matrix inquality(LMI)-based design methodology of decentralized robust reliable state-feedback controller was given by way of comparing the Lyapunov performance criterion of the subsystem operating normally with that of the same subsystem but suffering failure. The resulting control systems are robust and reliable in that guaranteed stability and performance were provided not onlyfor any admissible parameter perturbation, but also in case of control-channel outages. The apparently linear structure of the provided condition gives facilities for searching its numerical solution on computer and optimizing the performance specifications. Also, the relationship between reliable control and robust control of the large scale systems was analyzed with an interesting result obtained. A numerical example and the corresponding simulation was done to show the effectiveness of the proposed design method.
Pressure characteristics and control method of wind tunnel for sand and dust test
Yuan Lingshuang, Li Yunze, Wang Jun
2005, 31(05): 592-594.
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Pressure adjustment of wind tunnel for sand and dust test is different from general circumfluent one. In order to determine characteristics of pressure variation, dynamic model for controlling-pressure point, testing port andinjecting-sand-and-dust port was established, by the means of lumped parameter method(LPM) with physical analysis and simplification. Control method was offered according to the model. The rule that different disturbance effects on pressure distribution was observed, and control system of wind tunnel for sand and dust test was studied by the means of simulation. The results are satisfied. This work is important to optimize the configuration of the wind tunnel and to enhance its ability of sustaining pressure and is significant to ascertain the control precision for each component of the wind tunnel.

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