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2007 Vol. 33, No. 08

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Scan mirror motion compensation of geostationary satellite
Jia Yinghong, Xu Shijie
2007, 33(08): 873-877.
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The problem of mirror motion compensation was studied for a geostationary satellite to eliminate the optical axis direction deviation due to attitude deviation and normal line deviation of the mirror. The rotational dynamical equation of a spacecraft with two-degree freedom scan mirror was presented. The satellite attitude was described by Euler angles, and the normal line deviation of the mirror was described by Euler axis/angle parameters. The error transfer function from the two influencing factors to the optical axis direction was deduced. To resolve the problem of immeasurability of the normal line deviation, an estimation algorithm was presented using the precise direction finding ability of the scan mirror during special operation mode, and the long period character of the normal line deviation. The estimated value of the normal line deviation was replaced at set time intervals. Based on the estimation algorithm, a compensation algorithm was presented using the information of satellite attitude and normal line deviation, which compensated the scanning angle and the stepping angle separately. Numerical simulation results demonstrate the validity of the compensation algorithm.
Stator setting angles adjustment on performance improvement of axial-centrifugal compressor
Cao Zhipeng, Liu Bo, Ding Wei
2007, 33(08): 878-881.
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The quasi-three dimensional flow fields of axial-centrifugal compressor were solved with the streamline curvature method. Calculating stations were set in the leading edge, trailing edge and the middle of blade row. The streamline locations were fitted by cubic spline curves at each iteration computation. Performance calculation codes with loss and deviation angle models were developed by using the methods mentioned above. Available loss and deviation angle models were selected by considering the special configuration of axial-centrifugal compressor. At different rotational speed, optimum angles of IGV and stator one were determined by stator vane angle adjustment method and performance analysis codes of axial-centrifugal compressor. At 90% design speed, peak efficiency, three-dimensional numerical simulations were performed for detail flow field analysis of axial-centrifugal compressor. Research results indicate that stator vane angle adjustment can weaken the intensity of shock wave, decrease the loss, prevent the air flow deviation of the blade surface, and improve the performance of axial-centrifugal compressor.
Curvilinear synthetic aperture radar iterative algorithm
Tang Zhi, Li Jingwen, Wang Baofa
2007, 33(08): 882-885.
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Curvilinear SAR (synthetic aperture radar) 2-D signal model and 3-D signal model were studied. The curvilinear SAR echo signal mathematic equation was derived. Iterative algorithm was applied to curvilinear SAR. According to minimum non-linear variance criteria, RELAX algorithm cost function in curvilinear SAR was founded. Every procedure in 2-D RELAX algorithm and 3-D RELAX algorithm was studied in detail. The target scatter amplitude and position can be estimated. The recursive idea was presented. The convergence condition was given. The characteristic and computation for RELAX algorithm were analyzed. RELAX algorithm can converge quickly and its computation is comparatively small. Rigorous convergence condition can increase RELAX algorithm computation. The analysis provides direction for curvilinear SAR data 3-D information extraction with iterative algorithm.
Localization for mobile node based on sequential Monte Carlo
Lü Ke, Zhang Jun, Wang Gang, Ma Lin
2007, 33(08): 886-889.
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The accuracy and frequency of localization in wireless sensor networks play a crucial role in tracking and monitoring. Therefore, the study of high-efficient localization algorithm for accurate tracking is necessary. Through analyzing the traditional positioning based on Bayesian estimate process, the independent positioning of mobile node utilizing sampled sequential Monte Carlo algorithm was discussed. The application of Monte Carlo algorithm in positioning of wireless sensor networks was developed. This method has higher precision and does not need prior awareness of the wireless sensor networks and assumptions of node mobility. The algorithm maintains set of samples representing possible locations, achieves accurate localization cheaply with low seed density. Theoretical analysis and simulation experiments prove that Monte Carlo algorithm improves the positioning efficiency largely, utilizes sense information more effectively and decreases the impact of uncertainty. The properties of our technique were analyzed and experiment results from simulations were reported. The experiment results show that the sequential Monte Carlo localization technique can provide accurate localization.
New method of moving target detection using single-channel SAR ATI
Gao Fei, Sun Jinping, Yuan Yunneng, Bai Xia
2007, 33(08): 890-893.
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A detector for slow GMTI (ground moving target indication) with a single channel SAR (synthetic aperture radar) multi-look ATI (along track interferometry) was investigated. The steps include constructing multi-look using overlapped or unoverlapped windows, respective imaging, phase compensation and performing interferemetric processing. Concerning the crucial step of phase error rectification, a compensation method of phase calibration using SSP (signal subspace processing) was proposed. By this robust and adaptive approach,decorrelation between sub-images can be resolved and phase randomicity of multi-look ATI can be alleviated to some extent, moving targets can be isolated much easily from interferometric phase of multi-look sub-images. Simulation results show effectiveness of the method in moving targets detection in strong clutter, thus it provides reliable reference for single channel SAR GMTI and supports operational extension of existing SAR system.
Nonsubsampled Contourlet speckle reduction algorithm for SAR images
Guo Xujing, Wang Zulin
2007, 33(08): 894-897.
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The nonsubsampled Contourlet(NSCT) not only overcomes the disadvantage of wavelet, the nonoptimal basis for one-dimensional singularity, but also improves the edge preservation for the shift-invariance. Therefore, a speckle reduction model based on NSCT was presented. Firstly, original image with multiplicative noise was transformed into with additive noise by means of homomorphic transform. Then, the NSCT was implemented, including two steps which were nonsubsampled pyramids and nonsubsampled directional filter banks orderly. Finally, threshold denoising method was adopted to separate the noise and signal. The simulation experiments were carried out by traditional Lee filter, wavelet filter, Contourlet filter and the above NSCT denoising model. A comparison between them was given out for remote sensing images contaminated by multiplicative noise and synthetic aperture radar(SAR) original image. Experiment results show that the performance of the NSCT is superior not only in speckle reduction but also in edge preservation.
Aperture-dependent motion compensation for airborne SAR with 0.1 m resolution
Bai Xia, Sun Jinping, Gao Fei
2007, 33(08): 898-901.
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A new technological problem in 0.1 m resolution airborne SAR(synthetic aperture radar) motion compensation design procedure was discussed. High azimuth resolution means large synthetic aperture length and wide integration angle, thereby echo data collected in stripmap mode might include remarkable residual motion errors related with azimuth angle between the radar and the target. The impact of platform aperture-dependent motion errors in stripmap mode on airborne SAR image quality was analyzed. It shows that the errors cause geometry distortion and azimuth defocusing. Based on the relation between radar instantaneous illuminate time and Doppler frequency, an aperture-dependent motion compensation approach was put forward to improve image quality. This method applies segmentation and compensation data in azimuth direction and enters into the processing scheme integrated with conventional motion compensation,the first order motion compensation and the second order motion compensation. Simulation results validate the whole analysis and the proposed procedure.
Position and azimuth determination for land vehicles using electro-optical detection system
Wang Wei, Wang Dan, Feng Peide
2007, 33(08): 902-905.
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For the increasingly higher requirements of land navigation systems for the modern military vehicles, such as mobile silos, command stations, scout vehicles and so on, a new approach of position and azimuth determination for land vehicles was presented utilizing the angle information to three known landmarks measured by the electro-optical detection system which was mounted on the roof of the vehicle. Computer simulation results indicate that the position and azimuth of land vehicles can be accurately determined only based on once measurement information of each landmark by the electro-optical detection system, both estimation errors of vehicle position along east- and north-axis are mostly less than 0.5 meters, and the azimuth angle error can reach 20 arcsec (1σ). Besides high accuracy, the approach proposed is simple and quick, and it is capable of serving several land vehicles at the same time, hence it is of great value in practice.
Ontology-based simulation system lifecycle management system
Song Xiao, Gong Guanghong, Li Bohu
2007, 33(08): 906-910.
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Modeling and simulation(M&S) is a new and synthetic technology which has become the third means for recognizing and rebuilding the objective world besides the theory analysis and experiment research. Firstly, the concept of simulation system lifecycle management(SSLM) was proposed according to the requirement of M&S. Then it was pointed out that as an important supporting technology, SSLM can manage all the process and information in simulation system lifecycle and implement the functions which cannot be implemented by product lifecycle management(PLM) system. On the basis of the three-dimensional lifecycle model, the ontology-based method of SSLM content management was presented. The SSLM oriented ontology was built, which includes base ontology, domain ontology and application ontology. Finally the predicates in the SSLM ontology definition were organized into query sentences and semantic-based model searches were realized.
LMI based multi-objective robust control electro-hydraulic servo loading system
Wang Yanshan, Li Yunhua, Wang Yiqun
2007, 33(08): 911-914.
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To improve the performance of the multi-channel electro-hydraulic servo loading system, a multi-objective robust control method based on LMI(linear matrix inequalities) was proposed. Several factors such as parameter uncertainties, strong couplings among different loading channels, and performance differences caused by application of asymmetric hydraulic actuators for the loading system were all considered as a general uncertainty. The design process was composed of associating control system frequency band with performance weighting functions, associating system uncertainty with robust stability weighting functions and associating transient response behaviors with regional pole placement. By means of establishing and solving a LMI based convex optimization methodology, this multi-objective control problem can be solved subsequently. Simulation results show that the proposed control law design approach can achieve high dynamic performance and robust performance when the parameters of the electro-hydraulic servo loading system are changed in a wide range.
Closed-loop optimal fuzzy reasoning and its application
Zhang Lei, Zhang Jing, Shen Gongzhang
2007, 33(08): 915-919.
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The basic idea of optimal fuzzy reasoning is introducing optimization mechanism into fuzzy reasoning, while traditional fuzzy reasoning is an open-loop and optimization process. Firstly two main characteristics of fuzzy reasoning methods, reasoning consistency and approximation, were discussed for an existing optimal fuzzy reasoning method. Secondly the basic idea of closed-loop optimal fuzzy reasoning was provided, that is, introducing feedback and optimization mechanism into fuzzy reasoning, and a new method based on the idea was given. Thirdly the above characteristics for the new method was discussed. Proofs display that the two fuzzy reasoning methods both satisfy reasoning consistency and approximation. Based on the platform of a flight control system, simulation results display that the fuzzy-PID controller based on the closed-loop optimal fuzzy reasoning method has better control performance and more robustness. And the idea of closed-loop optimal fuzzy reasoning builds a full framework for treating fuzzy reasoning as a control problem.
Fault tolerant architecture design of EHA
Ma Jiming, Fu Yongling
2007, 33(08): 920-924.
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The integrated EHA (electrical hydrostatic actuator) is an important component of the PBW (power by wire) flight control system. Fault tolerant architecture design is necessary to improve the whole reliability of flight control system. Performance parameters were offered by the demand of reliability, mission abort, redundancy, failure management level, performance, weight and size. The failure rate about each EHA-s component was calculated. Based on the calculation result, a feasible fault tolerant architecture of EHA was selected. Then the probability of mission abort and loss of control results from the EHA-s failure were calculated separately. Calculation results show that the fault tolerant architecture can meet the flight control system-s reliability requirement. Detail design about EHA-s architecture was given based on the selected EHA-s reliability model, and this kind of EHA system-s function was described in particular.
Symbolic dynamics of coupled neuron model of calcium and voltage
Gao Zhiying, Lu Qishao
2007, 33(08): 925-929.
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The R15 neuron model with the intracellular calcium concentrations coupled to the transmembrane voltage was studied by the symbolic dynamics. The symbolic expressions of periodic and chaotic firing patterns were constructed through the first-return maps of ISIs (interspike interval series). And also the intermittent chaos close correlative to the fold bifurcation and the generating mechanism of periodic windows embedded in the chaos region were discussed. The corresponding relation between firing rhythms with different topological structures and continuously varying parameter values was revealed on the basis of ordering rules of symbolic sequences. The corresponding parameter value of some firing pattern measured from the electrophysiological experiment or simulated by the mathematical model could be approximately fixed according to the ordering relation. Results show that symbolic approach is a powerful tool to study neural firing activities. In particular, such a coarse-grained way can be generalized in neural electrophysiological experiments to extract more valuable information from complicated experiment data.
Fault diagnosis technology of launch vehicle based on distributed expert system
Liu Chengrui, Zhang Qingzhen, Ren Zhang
2007, 33(08): 930-932.
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A distributed fault diagnosis system scheme for launch vehicle was presented based on distributed expert system because of the characteristic of the launch vehicle including many subsystems which coupled with each other. In knowledge acquisition, the scheme used the production rule representation and described the experts- knowledge by the four-table structure composed by measure point table, symptom table, rule table and result table, which has the excellent versatility and transportability. Furthermore, the scheme combined the distributed inference and multi-level inference as the inference strategy. Because the distributed inference analyzes the system faults and each subsystem faults respectively at the same time, it can improve the diagnosis speed effectively. In addition, the multi-level inference can diagnose the faults with the high hazard rating preferentially. Therefore, once the highly hazardous faults of the launch vehicle happen, the fault diagnosis system can find them in time and give the maintenance measure to reduce their harm to the lowest level.
Extended Kalman filter method for micro-inertial strapdown attitude determination system
Shen Xiaorong, Zhang Hai, Fan Yaozu, Wu Guangyue
2007, 33(08): 933-935.
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Low precision micro-inertial gyros and accelerometers were used as elements of an inertial strapdown attitude system. Firstly, the nonlinear problem and the cause of accumulated error for inertial strapdown attitude solution were analyzed. Then according to the trigonometric function relationship between attitude angles, three variants replaced the roll and the pitch as state variants. Furthermore, with the restrained equation among state variants and the forward motion speed, one extended Kalman filter(EKF) model was built to solve the attitude angles. Using micro-inertial strapdown measurement unit MTi in the experiment to verify whether the EKF can restrain the accumulated error of the inertial attitude solution. The two results which come from EKF and from inertial attitude solution without compensation were compared, and show that the EKF algorithm can restrain the accumulated error.
Method of eliminating synchronism control error in flash butt welding of bill
Lu Ning, Fu Yongling, Sun Xinxue, Chen Zhanhui
2007, 33(08): 936-939.
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Based on the characteristics and the demands of synchronization, a single nero forecast controller was presented,which was designed to eliminate synchronization error of upset force in flash butt welding. A press feedback loop was designed to solve the problem that it is uneasy to assemble force sensor in flash butt welding. In view of the characteristics of hydraulic system, a nonlinear hydraulic system and a coupling model of mechanical system were designed in AMESim by control library and mechanical library,and the controller was designed in Simulink. In order to verify the performance of the new designed controller, the parameters of hydraulic system between branches were set different. An interface between controller and hydraulic system was designed in Simulink and AMESim, by which the eletro-hydraulic co-simulation was achieved. The result shows that the forecast controller exhibits excellent performance on eliminating synchronism of upsetting force in flash butt welding.
Characteristics analysis of dynamic model of 6-DOF Stewart platform
Guo Hongbo, Liu Yongguang, Li Hongren
2007, 33(08): 940-944.
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Based on the derived dynamic model of a six-degree-of-freedom (6-DOF) Stewart platform, some physical characteristics of the model were analyzed and proved in detail using matrix analysis method, which consist of the boundedness of the coefficient matrixes of dynamic model, the skew-symmetry of the matrix functions, and the linear parameterization of the complete dynamic model of the 6-DOF Stewart platform. These works laid a foundation for the development of the nonlinear control strategies to achieve higher system performance by incorporating more structural system information, i.e. a model into the controller, and proving the stability of the corresponding control system. Furthermore, the linear parameterization model of the complete dynamic model can also be used in the physical parameters estimation of the dynamic system.
Ni-MH battery state-of-charge estimation based on Kalman filter
Wu Hongjie, Qi Bojin, Zheng Minxin, Liu Yongzhe
2007, 33(08): 945-948.
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The state-of-charge(SOC) is an important parameter for the electrical vehicle. A new Ni-MH battery nonlinear dynamic model in discrete-time state-space form was introduced. In the new model, SOC and state-of-polarization as states of the state vector were introduced to represent the dynamic behavior of the battery more accurately. Taking into account the charge accumulating effect that influence the terminal voltage, the model was modified by adding an accumulating item into the state equation. The SOC estimation method based on extended Kalman filter was studied. The battery voltage, current, internal resistance and temperature were used in the algorithm. The calculation equations were presented in detail. Charge and discharge experiments with constant current, pulse current and variable currents were implemented. The simulation with these experiment data shows that the method is benefit to improve the accuracy of SOC estimation. The method can be used in a battery management system and applied in hybrid electrical vehicles.
Motion planning for humanoid robot based on instability capacity
Peng Zhaoqin, Fu Yongling, Zhao Ke, Tang Zhiyong
2007, 33(08): 949-953.
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In order to ensure that the robot can work safely in human-s living environment, the most stable trajectory should be selected to finish the task. A new stability evaluating criterion which can be used to evaluate the stability of different walking patterns of the humanoid robot was proposed. The distance between the ZMP(zero moment point) and the center of the supporting region was defined as instability capacity, and the instability capacities of several typical walking patterns were analyzed. In addition, the motion planning method based on instability capacity was proposed. In some cases, for an appointed task, many kinds of motions which have different step length can be used to finish the task, and the most suitable trajectory can be selected among those feasible trajectories using the instability capacity evaluating method. The effectiveness of this method was proved by simulation results.
Effects of PWB design factors on PTH reliability
Chen Ying, Huo Yujie, Xie Jingsong, Zhang Yuan
2007, 33(08): 954-958.
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Based on the barrel stress distribution model, the effect of printed wiring board(PWB) design factors such as plated through-hole(PTH) aspect ratio, the ratio of plating thickness over PTH radius, the ratio of board influence radius over PTH radius and glass transition temperature on PTH barrel stress and lifetime were studied quantitatively. Equivalent temperature load was introduced to found the barrel stress distribution model under different glass transition temperature. Results show that PTH life is sensitive to design factors when PWB operating at vicinities of the yielding temperature load. The PTH aspect ratio shows more significant impact when fixing the ratio of board influence radius over PTH radius. For the fixed PWB thickness, decrease PTH diameter results in the increase of PTH barrel stress and the decrease of PTH lifetime. PTH barrel strain sharply increases at the glass transition temperature. Results also show that the constant strain concentration coefficient is different in elastic and plastic stage.
Prediction method of monitoring displacement based on correlation coefficient stationary series with unequally spaced data
Ma Xiaobing
2007, 33(08): 959-962.
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An analysis method of unequally spaced correlation coefficient stationary series was established, which can be used into model buildings and prediction of displacement monitoring in geotechnical and hydraulic engineering. The integral maximum likelihood estimations of model parameters were derived from stochastic process theory; it can not only guarantee the good statistical properties but also solve the problem of unequally spaced time series analysis. Traditional interpolation method will result in an unacceptable error when the rate of data missing was relatively high, which was proved by the Monte Carlo simulation. It is shown that the estimations of the variance of displacement series are far from the true value. An example was given in the last section, which illustrates the advantage of presented method.
ICO multidisciplinary design optimization method
Han Minghong
2007, 33(08): 963-967.
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Some serious computational difficulties are found in application of collaborative optimization (CO). Reasons that cause computational difficulties in CO were analyzed. The L1 norm was used to improve subsystem consistency constraint and to avoid discontinuities in subsystem object function derivatives. Mathematical theory proved the convergency of the improve subsystem consistency constraint. Penalty function was added to system-level object function to convert unconstrained optimization into constrained optimization. A quick-start strategy was used to make the best use of optimal solution of system-level optimization in subsystem-level optimization. A new improved collaborative optimization (ICO) method was presented. Improved subsystem consistency constraint, system-level penalty function, and the quick-start strategy were used in ICO. These measures overcome the computational difficulties of CO better. Experiment results show that the robustness, reliability and computing efficiency of ICO are higher than those of CO.
Reliability estimation of a multi-state system
Wu Yueqin, Zhou Hong, Guan Jiancheng
2007, 33(08): 968-971.
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Multi-state consecutive-k-out-of-n system is the model that is generalized form two-state consecutive-k-out-of-n system. The reliability estimation of multi-state consecutive-k-out-of-n system is a hot and difficult spot in the reliability engineering field. When both the system and its components have different states: from complete failure up to perfect functioning and performance rate is associated with each component state, the reliability of the system was analyzed based on the reliability of components. The multi-state consecutive-k-out-of-n:F system may have different structures at different system levels. A new recursive algorithm for obtaining the system state distribution of multi-state consecutive-k-out-of-n:F system including the decreasing multi-state F system, the increasing multi-state F system, and other F systems was proposed. An instance was provided to illustrate the accuracy and availability of the method in the reliability estimation through comparison with the enumerating method. This algorithm is more effective for systems with many components. Moreover, it establishes foundation to the research on the complex multi-state system.
Modular production information system based on lean thinking
Meng Biao, Liu Zhicun, Fan Yuqing
2007, 33(08): 972-977.
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Many production organization obstacles must be overcome in manufacturing developing sometimes, and more, process reengineering will be promoted. This is always necessary along with the information system refining or evolvement constantly. Therefore, a production information system needs to meet the changing of organization environment with lowest improving cost. From enterprise basic data organization pattern, the basic data and its format were analyzed in detail in enterprise. Through data standardization with metadata, an environment was established with two-tier data center of enterprise and unit (sub-plant). The tightly relationship between enterprise business and basic data was divided into self-governed situation. The difference between data system and information system was defined. The concepts of enterprise business components, events and enterprise services were redefined based on business specialties. In this process, manpower and enterprise business were integrated into one information management frame. A lean production information system was quickly constructed with modular hierarchy, and the logical management process under such collaborative environment was expatiated deeply.
Simulation for early precipitation process of Ni75Al4V21 alloy by microscopic phase-field model
Zhao Yuhong, Zhang Yue, Chen Zheng
2007, 33(08): 978-981.
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The microscopic phase-field kinetic model for ternary system was applied to investigate the precipitation process of γ′ and θ phase in Ni75Al4V21alloy. The evolution of atomic pictures was simulated, and the composition and long-range order parameters of θ (Ni3V) and γ′ (Ni3Al) were calculated. The results show that θ forms earlier, its precipitation mechanism is congruent ordering followed by spinodal decomposition; By congruent ordering, a nonstoicheometric single θ ordered phase is produced with the order domains being separated by phase boundaries; Spinodal decomposition occurs predominantly at phase boundaries, and then the stoicheometric θ phase is formed; At the same time, γ′ (Ni3Al) appears at phase boundaries of θ phase by nonclassical different phase nucleation mechanism, the nonstoicheometric γ′ phase forms earlier and gradually transforms into the stoicheometric γ′ phase, so two kinds of ordered phases appear simultaneously in the system.
Experiment investigation of dynamic material property of aluminium alloy
Zhao Shougen, He Zhu, Yang Jialing, Cheng Wei
2007, 33(08): 982-985.
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Dynamic mechanical properties of four aluminum alloy were attained with the split Hopkinson pressure bar (SHPB) apparatus. According to the characters of the stress-strain curves, the Cowper-Symonds constitutive model was chosen and its relationship parameters were fitted according to the experiment data. The failure modes and their dynamic mechanical properties were compared among the four materials. The results show that LF6R and LF21M have good plasticity, LY12CZ and LC4CS have some brittleness. The tangent modulus linearly increase with yield stress. Among the four experimented aluminum-alloy materials, the strain-rate sensitivity of LC4CS is minimum; the strain-rate sensitivity of LF6R is maximum; the strain-rate sensitivity curves of LF21M, LY12CZ and LC4CS have the same shape.
Microstructure and affecting factors of epoxy resin cured by electron beam radiation
Li Yubin, Zhang Zuoguang, Sun Zhijie, Yang Jialing
2007, 33(08): 986-990.
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A scanning electron microscope (SEM) was used to observe the microstructures of cured samples after different cure time. The formation mechanism of microstructure was analyzed. The effects of molecular structure and molecular weight of epoxy resin, resin component, and radiation condition on the microstructure were also researched. The results show that the cure zone of epoxy resin consists of lamellae, and the resin molecular structure and weight have little effect on the cured microstructure. Under the electron beam radiation, epoxy resins with different structures or molecular weights all form prepolymer at first, then the prepolymer grows into network. With the radiation time increases, the network grows larger and the circular sheet forms finally. With the increasing of radiation dosage, the size of circular sheet increases. And there exists an optimum content of initiator, which makes the size of circular sheet reach the minimum.
Effect of nuclear radiation on dielectric properties of wave-transmitting materials
Gong Zhaohe, Liu Jianhua
2007, 33(08): 991-993.
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The effect of nuclear radiation on dielectric properties of epoxy TDE-85/glass fiber E composite and bismaleimide 4501A/glass fiber D3W composite was studied in oxygen ambience using accelerated aging mothed. After samples were irradiated by 60Co -rays at a range of dose 50~800kGy in air, the dielectric loss and dielectric permittivity of materials were measured using wave-guide method at 10GHz. It was found that the dielectric loss and dielectric permittivity increases with radiation dose, but increasing is not much, and the antiradiation property of 4501A/glass fiber D3W composite is better than that of TDE-85/glass fiber E composite. The change reasons of the dielectric property were analyzed using infrared (IR) and dynamic thermo gravimetric analysis (TGA) .
Reflection based distributed interactive simulation framework
Huang Xiaodong, Li Bohu, Chai Xudong, Song Changfeng
2007, 33(08): 994-999.
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　Adaptability is one of the most important qualities of the software frameworks, for which are used in various applications of a field. Reflection was introduced to improve the adaptability and support re-configuration of a modeling and simulation framework for the development of large scale simulation systems. Through the reflection of architecture of the framework, the framework supported architectural evolution and re-configuration in run time. Through the reflection of context of the simulation component or object models, the models supported dynamic representation and behavioral evolution. By organizing the reflective information into memory database which was maintained by HLA/RTI, the system was repository-centered architecturally. As a result, security of the reflective system was improved and a new design pattern based on the reflective database was presented. On the other hand, the interface of RTI was encapsulated, so a more advanced distributed computing environment and simulation engine with friendly interface was provided, which could support the development of applications rapidly and strongly.
Decision support system based on 3-D cluster
Zhang Yongmei, Li Bo
2007, 33(08): 1000-1004.
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According to the requirement of the topography selection, the present spatial cluster technology and methods were studied deeply, a structural element was established. A new algorithm of 3-D spatial clustering based on mathematical morphology was presented. The process of spatial data mining was given, and an artillery position selection system was realized. The algorithm realized cluster of spatial objects through closing. It could not only complete 3-D spatial cluster at a time, but also handle cluster in-convex and complicated objects rapidly. On the basis of mathematical morphology, the algorithm was easy to implement its high performance parallel algorithm. Experiment results show that the algorithm can supply an effective solving scheme for the computer realization of the artillery position selection, and discover the potential relationships and rules in vast spatial database when it is applied to the development of the artillery position selection system, so it can help decision makers to make sensible decisions.

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