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Full-Text Articles in Physical Sciences and Mathematics

Visualization Of Tropical Cyclones Based On Digital Earth, Shuoben Bi, Yucheng Gong, Mingyue Lu, Zhou Hao, Tang Zhi Mar 2020

Visualization Of Tropical Cyclones Based On Digital Earth, Shuoben Bi, Yucheng Gong, Mingyue Lu, Zhou Hao, Tang Zhi

Journal of System Simulation

Abstract: Tropical cyclones are often accompanied by heavy rains, storm surges and so on, which have serious impact on the southeast coast of China. Visualization of tropical cyclones can directly demonstrate its motion state, occurrence process and internal structure, and support the research and prediction on it. This paper builds digital earth platform based on Cesium(an open source library),introduces the system architecture, verificates the applicability of point cloud method to the visualization of cloud field data, proposes an improved wind field visualization method based on particle tracking, with includes the calculation of wind field particle properties, the drawing of wind …


Model Of Initial Spare Parts Configuration And Ordering Policy Optimization Based On Inventory State, Songshi Shao, Minzhi Ruan, Zhihua Zhang Mar 2020

Model Of Initial Spare Parts Configuration And Ordering Policy Optimization Based On Inventory State, Songshi Shao, Minzhi Ruan, Zhihua Zhang

Journal of System Simulation

Abstract: Rational planning of spare parts configuration project is an effective approach to improve the equipment availability and reduce the life cycle cost (LCC). First of all, the spare parts demand rate forecast model is constructed. According to the systemic analysis method, the spare parts support effectiveness evaluation targets system is built, and then, the initial spare parts configuration optimization method is researched. Aim to the consumption for partial repairable spare parts, the expected backorders function of the approximate Laplace demand distribution is given. Combining the (s-1, s) and (R, Q) inventory policy, the ordering model is established under the …


Maritime Radar Terrain Echo Simulation Based On Dem And Sar, Yongfeng Suo, Shenhua Yang, Guoquan Chen, Zhuqiang Xiang Mar 2020

Maritime Radar Terrain Echo Simulation Based On Dem And Sar, Yongfeng Suo, Shenhua Yang, Guoquan Chen, Zhuqiang Xiang

Journal of System Simulation

Abstract: Due to the huge amount of work required for terrain database building, the application of navigation radar simulation on the reflectivity of land object has been greatly limited. A novel radar simulation method is proposed based on the DEM(Digital Elevation Model) data and the same-band SAR(Synthetic Aperture Radar) reflection data. The target reflectance information is obtained, which is used as the basis for the surface radar reflectivity simulation. In combination with the radar equations, the surface reflectivity model of the navigation radar is established. Taking into account the elevation shielding relationship of the radar echo topography, an algorithm of …


Analysis Of Aeroengine Vibration Signal, Pi Jun, Jiaze Chang, Guangcai Liu Mar 2020

Analysis Of Aeroengine Vibration Signal, Pi Jun, Jiaze Chang, Guangcai Liu

Journal of System Simulation

Abstract: Aiming at the analysis of the vibration characteristics of aeroengine rotor, an improved blind source separation algorithm based on cumulant independent component analysis (ICA) is proposed. The new algorithm is used to separate the rotor vibration signal and identify the rotor fault types. The effectiveness of this algorithm is verified by the aeroengine rotor vibration signal simulation. Comparing with the existing algorithms based on second-order cumulants and high-order cumulants, the new method improves the performance index and the signal similarity coefficient. This algorithm is used to separate the vibration signal collected by the engine rotor platform and the rotor …


Spatial Structure Optimization Of Natural Forest Based On Bee Colony-Particle Swarm Algorithm, Dongsheng Qing, Xiaofang Zhang, Jianjun Li, Guo Rui, Qiaoling Deng Mar 2020

Spatial Structure Optimization Of Natural Forest Based On Bee Colony-Particle Swarm Algorithm, Dongsheng Qing, Xiaofang Zhang, Jianjun Li, Guo Rui, Qiaoling Deng

Journal of System Simulation

Abstract: The natural forest spatial structure contains the spatial location information of the forest, which affects the growth, competition and stability of the forest development. Its optimization is a multi-objective programming problem. A bee colony particle swarm optimization (ABC-PSO) hybrid algorithm is proposed, which improves the initial particle generation mechanism, the number of follow bees and the circulation mechanism. The algorithm is applied to the multi-objective optimization of the spatial structure of natural forest. An optimization model which takes account of the tree distribution grid, tree size segmentation and tree competition is established. The simulation results show that the bee …


Research On Evolution Model Of Online Public Opinion Based On Temporal Network, Li Feng, Wei Ying Mar 2020

Research On Evolution Model Of Online Public Opinion Based On Temporal Network, Li Feng, Wei Ying

Journal of System Simulation

Abstract: With the in-depth study on the social medias, the social networks of online platforms are recognized gradually as the time-varying temporal networks. In order to compare and analyze the information diffusion process and the result, the analysis method of computer simulations is adopted, a temporal network is generated, and the SIR model is used as the online public opinion diffusion model. The simulation results based on multi-agent approach show that the uncertainty of information diffusion on the social platforms comes from the complicated structure of the temporal networks and the SIR model. In addition, the misunderstanding of the social …


Performance Balanced Opportunistic Routing And Simulation Analysis Based On Cooperative Game, Huahong Ma, Honghai Wu, Guoqiang Zheng, Baofeng Ji Mar 2020

Performance Balanced Opportunistic Routing And Simulation Analysis Based On Cooperative Game, Huahong Ma, Honghai Wu, Guoqiang Zheng, Baofeng Ji

Journal of System Simulation

Abstract: Opportunistic transmission mode of “store-carry-forward” is usually used to make routing in mobile opportunistic network. Currently, there have been many researches in this area. However, the existing opportunistic routing mechanisms pay much attention to the single index of delivery success ratio, but neglect the constraints on other performance indicators, which may lead to the extreme imbalance of network performance. Aiming at this issue, the diffusion of data packets between multiple nodes are modeled as a cooperative game with the goal of maximal performance balancing, and an opportunistic routing protocol based on the cooperative game for performance balancing is proposed. …


Multi-Uav 3d Formation Path Planning Based On Improved Artificial Potential Field, Haiyun Chen, Huazhou Chen, Liu Qiang Mar 2020

Multi-Uav 3d Formation Path Planning Based On Improved Artificial Potential Field, Haiyun Chen, Huazhou Chen, Liu Qiang

Journal of System Simulation

Abstract: Focusing on the GNRON (goal nonreachable with obstacles nearby), the local minima and chattering of the traditional artificial potential field method, the potential field functions are improved and analyzed to guarantee the goal is the global minimum. In the dynamic potential field, a mechanism of judging whether to fall into local minima is introduced, a method of “moving along the orientation of 90° of goal direction” is used to jump out of the local minima, and the path planning of multi-UAV formation, the synergistic obstacle avoidance and collision prevention are achieved. The path is optimized by applying the regression …


Parallel Computing Of Multi-Agent System In Spatially-Explicit Modeling And Simulation, Hongchun Qu, Xianhui Yao, Yin Li Mar 2020

Parallel Computing Of Multi-Agent System In Spatially-Explicit Modeling And Simulation, Hongchun Qu, Xianhui Yao, Yin Li

Journal of System Simulation

Abstract: Aiming at the synchronization in the spatially-explicit parallel simulations, a limited optimistic synchronization algorithm based on Agent sensing region is proposed. The algorithm inherits the advantages of the optimistic synchronization algorithm and the security-guaranteed conservative synchronization algorithm. The algorithm categories all simulated agents into the security agent region and non-security agent region. The simulation is performed through the collaboration between the dispatch server and the execution servers where simulation tasks are scheduled and executed. The dispatch server determines whether an agent is in a security zone according to the security radius. The execution servers are responsible for performing the …


A Game Cheating Detection System Based On Petri Nets, Zheng Hong, Ye Cheng, Wenxuan Deng, Pan Li Mar 2020

A Game Cheating Detection System Based On Petri Nets, Zheng Hong, Ye Cheng, Wenxuan Deng, Pan Li

Journal of System Simulation

Abstract: Game cheating endangers the normal cyber game seriously. The bottlenecks of the anti-cheating technology are the low efficiency and its too much dependence on the signature matching. Not relying on the signature matching, a highly efficient game cheating detection system is proposed, which models by process trees. This can save the storage space without affecting the detection results. The system is tested with the cheating softwares on the popular cyber game and the fusion efficiency of the update model is evaluated. The results show that the storage space reduction rate can reach about 60%, which means effectiveness and feasibility …


Simulation Research And Application On Urban Rail Transit Fully Automatic Operation System, Du Heng, Chunhai Gao, Huang Qing, Huaiming Cang Feb 2020

Simulation Research And Application On Urban Rail Transit Fully Automatic Operation System, Du Heng, Chunhai Gao, Huang Qing, Huaiming Cang

Journal of System Simulation

Abstract: Following the development of the key technologies for the Fully Automatic Operation (FAO) of urban rail transit and the application of autonomous fully automatic operation system demonstration projects, more and more urban rail transit lines choose the FAO system. High availability, high reliability and high security also need high requirements on the testing and verification before the line is operated. Through the simulation research of the fully automatic operation system, combined with the comprehensive debugging and verification management platform of the Yanfang Line's fully automatic independent demonstration project, the scenario-based FAO system simulation model is established, the key technologies …


Research On Cavitation Evolution Model In Venturi Tube, Guihua Han, Yanan Liu, Junpeng Shao, Cijun Zhang Feb 2020

Research On Cavitation Evolution Model In Venturi Tube, Guihua Han, Yanan Liu, Junpeng Shao, Cijun Zhang

Journal of System Simulation

Abstract: The dynamic cavitation model of venturi tube air-water two-phase flow was established according to the time variation of air precipitation and digestion process in water. FLUENT three-dimension numerical simulation were studied to simulate the air-water two-phase flow, and the variation law of venturi tube throat diameter and inlet pressure on vapor volume fraction were obtained. The results of numerical simulation and experiments show that the vapor volume fraction increases following the increase of the inlet pressure. If the throat diameter is increased, the inlet pressure can be increased as the compensation to achieve the same cavitation effect. The …


Modelling And Simulation For NoX Emission Concentration Of Scr Denitrification System, Dong Ze, Laiqing Yan Feb 2020

Modelling And Simulation For NoX Emission Concentration Of Scr Denitrification System, Dong Ze, Laiqing Yan

Journal of System Simulation

Abstract: The selective catalytic reduction (SCR) denitrification system has the features of non-linearity, large lag and strong disturbance, when the operating condition changes. Based on mutual information (MI) and Kernel-based Orthogonal Projections to Latent Structures (KOPLS), the model for NOx emission concentration is proposed. The time-delay of each input variable is estimated by mutual information, and phase space construction is performed, KOPLS is utilized to modelling. KOPLS shows the merits of strong generalization, nonlinear fitting and anti-noise in the simulation of benchmark datasets. According to field data analysis, RMSE of MI-KOPLS in training and test are reduced by 17% …


Situation Cognition And Decision Modeling Method For Submarine Operation Based On Discriminant Matrix, Dongjun Zhang, Weiping Wang, Li Xiao, Zhang Lei, Xiaobo Li, Guojie Liu Feb 2020

Situation Cognition And Decision Modeling Method For Submarine Operation Based On Discriminant Matrix, Dongjun Zhang, Weiping Wang, Li Xiao, Zhang Lei, Xiaobo Li, Guojie Liu

Journal of System Simulation

Abstract: Submarine operations have the characteristics of dynamic game confrontation in complex environments. Situation cognition and decision (SCD) behavior of combatants have an important impact on the effectiveness of submarine operations. Aiming at the SCD modeling in submarine engagement-level operational experiments, based on analyzing the SCD process, the representative variable set is refined, and a SCD modeling method for submarine operation based on the discrimination matrix is proposed. The submarine engagement-level confrontation is used as an example to study the SCD process in the given scenarios, and the feasibility and effectiveness of the method are verified. The established model …


Moea/D Algorithm Based On The Hybrid Framework For Multi-Objective Evolutionary Algorithm, Hongjun Tian, Wang Lei, Qidi Wu Feb 2020

Moea/D Algorithm Based On The Hybrid Framework For Multi-Objective Evolutionary Algorithm, Hongjun Tian, Wang Lei, Qidi Wu

Journal of System Simulation

Abstract: Aimto the difficulties of designing the bonding mechanism of global optimization algorithm and local search strategy for hybrid multi-objective evolutionary algorithm, and of improving the performance of multi-objective evolutionary algorithms, based on the feedback control idea, a systematic and modular hybrid MOEA/D algorithm combining the global optimization and local search is proposed. In the algorithm, a diversity measure method based on crowded entropy is designed; a local search strategy based on simplified quadratic approximation and population diversity enhancement strategy for MOEA/D is proposed. The numerical experiments show that the proposed HMOEA/D can achieve a balance between diversity …


Research On Approximate Reference Algorithm Of Svdbn Based On Sliding Window, Haiyang Chen, Chai Bing, Ruilan Wang, Cao Lu Feb 2020

Research On Approximate Reference Algorithm Of Svdbn Based On Sliding Window, Haiyang Chen, Chai Bing, Ruilan Wang, Cao Lu

Journal of System Simulation

Abstract: Structure-variable dynamic Bayesian networks (SVDBN) have the special advantage in dealing with the uncertainty of the unstable processes. In order to overcome the disadvantage that the inference algorithms of the SVDBN are unable to apply online, introducing the concepts of SVDBN sliding window and the window width, the online approximate inference mechanism of structure-variable dynamic Bayesian networks based on sliding window is explained, and two online algorithms are proposed, that is the recursive inference algorithm of structure-variable discrete dynamic Bayesian networks (SVDDBN) based on sliding window and the fast inference algorithm of SVDDBN based on sliding window. Experimental simulations …


Demand Forecasting Of Wartime Spares Based On Evidence Theory, Yunjing Zhang, Xinxin Wang, Wang Yang, Guangming Tang Feb 2020

Demand Forecasting Of Wartime Spares Based On Evidence Theory, Yunjing Zhang, Xinxin Wang, Wang Yang, Guangming Tang

Journal of System Simulation

Abstract: A new method based on evidence theory is proposed to solve the lack of data for the demand prediction of spares in wartime. Utilizing Markov chain model to research the rule of spares demand of peacetime from the historical data. A Markov chain transfer probability adjustment strategy, based on the change of combat intensity, is designed, which can be used to simulation the rule of spares demand in wartime. Under the experience of experts and the combination of the Fuzzy theory and evidence theory, the spares demand is wartime is forecasted. The simulation example shows that the …


Shielding Modeling And Simulation Of Coastal Building To Vts Radar, Chunhui Zhou, Zhou Ling, Langxiong Gan, Xiaodong Cheng, Junjie Gao Feb 2020

Shielding Modeling And Simulation Of Coastal Building To Vts Radar, Chunhui Zhou, Zhou Ling, Langxiong Gan, Xiaodong Cheng, Junjie Gao

Journal of System Simulation

Abstract: In order to study the shielding influence of coastal building on the VTS radar, a mathematical expression model of shielding area is proposed. The expression model are divided into finite continuous 3D shielding area, infinite continuous 3D shielding area, finite discontinuous 3D shielding area and infinite discontinuous 3D shielding area. The range and height of the shielding area are calculated, according to the expression model and spatial geometric relation. In addition, 3ds MAX is used in the modeling and simulation of shielding area. Taking the influence of Prince's Bay Cruise Terminal Building on the radar Shekou radar as an …


Improving The Efficiency Of Transport Systems Using Simulation, Bushuev Sergey, Kovalev Igor, Permikin Vadim, Anashkina Nataliia Feb 2020

Improving The Efficiency Of Transport Systems Using Simulation, Bushuev Sergey, Kovalev Igor, Permikin Vadim, Anashkina Nataliia

Journal of System Simulation

Abstract: The article describes the possibilities of application of simulation modeling for the analysis of infrastructure and technology of transport services of enterprises. The main technological and possible economic effects for the enterprises arising at performance of modeling of a transport component of their work are resulted.


Interference Management Mechanism In Next Generation Dense Wlan, Ronghui Hou, Xiaoyao Ma, Liu Yi, Hongyan Li Feb 2020

Interference Management Mechanism In Next Generation Dense Wlan, Ronghui Hou, Xiaoyao Ma, Liu Yi, Hongyan Li

Journal of System Simulation

Abstract: Aiming at the unfairness and low throughput in a wireless local area network with dense access points and terminals deployment, a user-centered resource allocation method which can configure the specific channel and power level for each user is proposed. This method can maximize the network throughput while ensuring the minimum throughput requirement for each user. The proposed interference management mechanism and user identification method can be easily implemented in the current wireless local area network system. Simulation results show that the proposed resource allocation scheme enhances about 47.3% throughput to a basic service set. In particular, 190% improvement can …


Cuckoo Search Algorithm With Dynamic Step And Discovery Probability, Jingsen Liu, Xiaozhen Liu, Li Yu Feb 2020

Cuckoo Search Algorithm With Dynamic Step And Discovery Probability, Jingsen Liu, Xiaozhen Liu, Li Yu

Journal of System Simulation

Abstract: In order to further improve the low accuracy and slow convergence speed of algorithm search, a cuckoo search algorithm with dynamic step size and probability of discovery is proposed. The algorithm dynamically constrains the Levy's moving step of each generation by introducing the step adjustment factor, which makes the Levy's flight mechanism adaptive. In the probability of finding, the random inertia weight with uniform distribution and F distribution is used to change the fixed value of the probability of discovery, to strengthen the diversity of the population and to keep the balance between global search and local exploration. The …


Research On Motion Cueing Algorithm Based On Vr Motion Simulator, Xiaolu Li, Jianfeng Yan, Cangsu Xu, Zongming Wu, Yuanhui Zhang, Junjiang Zhu Feb 2020

Research On Motion Cueing Algorithm Based On Vr Motion Simulator, Xiaolu Li, Jianfeng Yan, Cangsu Xu, Zongming Wu, Yuanhui Zhang, Junjiang Zhu

Journal of System Simulation

Abstract: Aiming at the phase delay and the false suggest of the classical motion-sensing simulation algorithm in VR motion simulator that lead to insufficient consistency between virtual and real movement and cause VR motion sickness disease, an improved motion-sensing simulation algorithm is proposed. Based on the classical simulation algorithm, the algorithm compromises the vestibular sensory system, feeds back the output error, and applies the fuzzy control algorithm to modify and forecast the input acceleration and angular velocity. This improved motion-sensing simulation algorithm is trained in the condition of virtual choppy terrain. The MATLAB/Simulink simulation results show that the improved motion-sensing …


Auv Vertical Plane Control Based On Improved Pid Neural Network Algorithm, Runan Huang, Ding Ning Feb 2020

Auv Vertical Plane Control Based On Improved Pid Neural Network Algorithm, Runan Huang, Ding Ning

Journal of System Simulation

Abstract: An improved PID neural network controller is designed for the movement control of a small low-speed autonomous underwater vehicle (AUV) in vertical plane, and the global control of the depth and pitch angle of the underwater vehicle in vertical plane is obtained. The AUV simulation control system is built by using REMUS underwater vehicle model in Simulink. The simulation results show that the improved control method with better dynamic performance has solved the original excessive saturation issue, and can adapt to different learning rates and network initial weight,and is of certain reference value to the practical application …


Research On Glide Width Simulation System Of Instrument Landing System, Chunying Jiang, Yuxiang Kang, Xiaofeng You, Xiaoxin Zhang, Changlong Ye Feb 2020

Research On Glide Width Simulation System Of Instrument Landing System, Chunying Jiang, Yuxiang Kang, Xiaofeng You, Xiaoxin Zhang, Changlong Ye

Journal of System Simulation

Abstract: Based on the principle of the formation of the instrumental landing system ILS(Instrument Landing System) gliding DDM(Different in the Depth of Modulation) index, and the factors that affect DDM are found as the amplitude of SBO(Sideband Only) signal. The relationmodel between the amplitude and the glide width, of the Half-width SBO signal in the linear variation range of DDM are obtained by the control variable method. And Based on the measured data, the correctness of the model is verified. Based on the mathematical model and combined with the NM7000 equipment, a simulation system is built to dynamically …


Tele-Robot Control System With Online Virtual Simulation Prediction, Lingyan Hu, Kangbai Shi, Bichun Zhang, Shaoping Xu Feb 2020

Tele-Robot Control System With Online Virtual Simulation Prediction, Lingyan Hu, Kangbai Shi, Bichun Zhang, Shaoping Xu

Journal of System Simulation

Abstract: When a tele-robot with virtual simulation system works in a complicated environment, the virtual scene may not synchronize with the real one. This may cause the operator on the master side to give wrong instruction. This paper presents a tele-robot with online virtual model correction. The virtual simulation system on the master side builds a virtual model of environment and robot on the slave side. It predicts the motion of the slave robot in real time according the commands from the operator. In order to ensure the virtual scene synchronize with the real one, the measured data on the …


Monocular Depth Image Mark-Less Pose Estimation Based On Feature Regression, Chen Ying, Shen Li Feb 2020

Monocular Depth Image Mark-Less Pose Estimation Based On Feature Regression, Chen Ying, Shen Li

Journal of System Simulation

Abstract: Monocular camera mark-less pose estimation system suffers low accuracy, robustness and efficiency due to variety of action, self-occlusion of human body. A method of feature exaction from point clouds was proposed, in which a single-to-multiple (S2M) feature regressor and a joint position regressor were designed to quickly and accurately predict the 3D positions of body joints from a single depth image without any temporal information. Experiment result shows that the estimation accuracy is superior to that of state-of-the-arts and multi-camera based methods.


Integrated Simulation Test Platform For Environment Perception And Planning Decision Of Intelligent Vehicle, Sun Jian, Runhan Huang, Li Lin, Qiyuan Liu, Yudi Li Feb 2020

Integrated Simulation Test Platform For Environment Perception And Planning Decision Of Intelligent Vehicle, Sun Jian, Runhan Huang, Li Lin, Qiyuan Liu, Yudi Li

Journal of System Simulation

Abstract: The simplicity of testing modules and the lack of high-fidelity and high-density traffic scenes are the primary issues in the intelligent vehicle' simulation test. To solve these problems, a "software in the loop" integration test platform is built. The environmental perception module is integrated on the basis of the PreScan, the planning decision-making module designed by MATLAB/Simulink and the virtual traffic flow environment from Vissim. Based on this platform, high-fidelity traffic flow scenes can be generated rapidly to support the test of environment perception and decision-making integratedly and effectively. Moreover, the intelligent vehicle's influence on the traffic flow …


Simulation And Optimization Of Aircraft Sliding Path, Zhiwei Xing, Mingyi Xu, Luo Xiao, Luo Qian Feb 2020

Simulation And Optimization Of Aircraft Sliding Path, Zhiwei Xing, Mingyi Xu, Luo Xiao, Luo Qian

Journal of System Simulation

Abstract: Variable taxiing time is an important indicator to the characteristics of the airport traffic flow assessment, which affects the airport operating efficiency, the passenger satisfaction for the airline and the pollution emissions. For a large hub airport, according to the principle of cellular automata and the congestion of traffic flow, the airport taxiing area is regarded as the network topology of nodes and links, and the conflict between taxi rules and aircraft is taken as the constraint. The simulation analysis is carried out on the basis of constructing the model of airplane departure traffic flow, using Monte Carlo algorithm …


Self-Organizing Aggregation Behavior Modeling Of Swarm Robots Based On Ant Colony Algorithm, Yang Wei, Zeng Liang, Xinchen Kang Feb 2020

Self-Organizing Aggregation Behavior Modeling Of Swarm Robots Based On Ant Colony Algorithm, Yang Wei, Zeng Liang, Xinchen Kang

Journal of System Simulation

Abstract: Aiming at the formation of aggregation behavior model of swarm robots, a self-organizing motion model based on particle system mechanics and perceptual state weighting is established to realize the autonomous transfer of robot motion state. The aggregation degree and uniformity index of aggregation behavior are established, and the aggregation performances of different models are analyzed by experiment, which lay a foundation for the formation of self-organized aggregation behavior model of swarm robots. Using the selected model, the self-organizing aggregation behavior simulation experiments are conducted in two cases with boundary constraints and no boundary constraints. The maximum coverage of …


Cascade Transmission Evaluation Of Ecosystem Damage Caused By Dust Migration, Guangqiu Huang, He Tong, Qiuqin Lu Feb 2020

Cascade Transmission Evaluation Of Ecosystem Damage Caused By Dust Migration, Guangqiu Huang, He Tong, Qiuqin Lu

Journal of System Simulation

Abstract: To solve the cascade transmission evaluation of ecosystem damage caused by dust migration in mining area, the migration network is constructed by dust migration path, and the potential hazard source path is identified. The definition of Petri-net simulation model of ecosystem damage with cascade propagation (PN-EDCP) is given, and the general method of abstracting migration paths network into a Petri net model is expounded. By introducing the concepts of attributes and methods of place objects into Petri net model, the real meaning of the model is clear, and the ability of describing and analyzing the logical relationship between ecosystem …