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Systems Science Commons

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2021

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Articles 241 - 270 of 323

Full-Text Articles in Systems Science

Modeling Of Adversarial Behavior On Road Network Based On Non-Cooperative Game, Xiangyu Wei, Zhang Qi Feb 2021

Modeling Of Adversarial Behavior On Road Network Based On Non-Cooperative Game, Xiangyu Wei, Zhang Qi

Journal of System Simulation

Abstract: The modeling of adversarial behavior is the key to the study of various military-like confrontation problems. Existing research mainly focus on the target domain, but in reality, many confrontation problems occur on the road network. Combined with the network flow representation of adversarial behavior, a network adversarial game modeling framework based on non-cooperative games is proposed, and a novel road network confrontation problem—network evasion interdiction game is given based on the framework. Simulation experiments show that the new double oracle algorithm performs better than the original linear solution algorithm. Data experiments based on real road networks further verify …


Behavior Modeling For Computer Generated Forces Based On Machine Learning, Zhang Qi, Junjie Zeng, Xu Kai, Qin Long, Quanjun Yin Feb 2021

Behavior Modeling For Computer Generated Forces Based On Machine Learning, Zhang Qi, Junjie Zeng, Xu Kai, Qin Long, Quanjun Yin

Journal of System Simulation

Abstract: With the rapid development of Machine Learning, especially deep learning, it has become an important way of modeling Computer Generated Force (CGF) behavior by ML methods, which can overcome the challenges of traditional methods. The existing research and application of three typical learning methods in CGF behavior modeling are discussed, and the effects of introducing learning into different stages of the typical CGF applications are analyzed, and the function and performance requirements of CGF behavior modeling using machine learning are proposed. Four potential research directions in the field for future are proposed.


Refined Alignment Method For Single-Axis Rotary Inertial Navigation Based On Fuzzy Adaptive Filtering, Hu Jie, Xiaozhu Shi Feb 2021

Refined Alignment Method For Single-Axis Rotary Inertial Navigation Based On Fuzzy Adaptive Filtering, Hu Jie, Xiaozhu Shi

Journal of System Simulation

Abstract: In order to restrain the influence of saw tooth velocity error caused by the inertial measurement unit (IMU) rotation on the initial alignment accuracy of single-axis rotary strapdown inertial navigation system (SINS), a refined alignment method based on fuzzy adaptive Kalman filtering is proposed. After calculating the ratio of actual covariance to theoretical covariance of the innovation sequence, the method adaptively adjusts the measurement noise covariance matrix by using the fuzzy inference system (FIS), so that it can adapt to the changes of measurement noise caused by IMU rotation. The initial alignment validation experiments under the swing environment …


An Intrusion Detection Algorithm Based On Ifoa And Welm, Jianwu Dang, Tan Ling Feb 2021

An Intrusion Detection Algorithm Based On Ifoa And Welm, Jianwu Dang, Tan Ling

Journal of System Simulation

Abstract: An intrusion detection algorithm of WELM optimized by IFOA is proposed. The advantages of short training time and good generalization performance of WELM are used, and the weight of minority attacks is increased, so that the recall rate of minority attacks in network attacks is greatly improved.The FOA with adaptive adjustment of the iterative step size is used, so the input weights and bias of the hidden layer in the WELM are globally optimized to avoid the algorithm falling into local optimal solution and realize the classification of the NSL-KDD intrusion detection data set. The experimental results show …


Flight Simulation Modeling Method Based On Improved Euler Angle Formula, Lishan Jia, Li Ang Feb 2021

Flight Simulation Modeling Method Based On Improved Euler Angle Formula, Lishan Jia, Li Ang

Journal of System Simulation

Abstract: Aiming at the singularity problem of common full flight motion equation, a modeling method based on improved Euler angle formula is proposed. On the basis of the modified small perturbation modeling equation, this method increases the influence of aircraft maneuvering surface on the aircraft Euler angle and a variable step solution algorithm is used. The model can overcome the singularity problem of common Euler equation, and the accuracy of model calculation is higher than other flight simulation models which overcome the singularity of Euler equation. Compared with the flight simulation model using the conventional Euler angle formula, the proposed …


Integrated Design And Simulation Of A Giant Magnetostrictive Driving Positioning And Vibration Suppression System, Xiaoqing Sun, Hu Wei, Yucheng Liu, Zhilei Wang, Hu Jun Feb 2021

Integrated Design And Simulation Of A Giant Magnetostrictive Driving Positioning And Vibration Suppression System, Xiaoqing Sun, Hu Wei, Yucheng Liu, Zhilei Wang, Hu Jun

Journal of System Simulation

Abstract: Aiming at the ultra-precision positioning and vibration suppression for sensitive payloads on-orbital working environment, a giant magnetostrictive driving positioning and vibration suppression system is proposed. The passive vibration isolation performance is selected as the optimization objective to realize the optimization design of the key part of the integrated system. The dynamic model of the whole system is built and the simulation model is constructed through Simulink. The simulation analysis and experimental tests are carried out to test the integrated system. The results show that the proposed integrated system realizes the ultra-precision positioning, and suppresses the vibration above 60 Hz, …


Longitudinal Adaptive Control Of Autonomous Vehicles Base On Optimization Algorithm, Zhishuai Yin, Jiaxiong He, Linzhen Nie, Jiayi Guan Feb 2021

Longitudinal Adaptive Control Of Autonomous Vehicles Base On Optimization Algorithm, Zhishuai Yin, Jiaxiong He, Linzhen Nie, Jiayi Guan

Journal of System Simulation

Abstract: Aiming at the nonlinear, time-varying and uncertain characteristics of the longitudinal motion of autonomous vehicles, a Radial Basis Function neural network(RBFNN) Proportional Integral Derivative(PID) controller base on Particle Swarm Optimization(PSO) is designed. A RBFNN is integrated into a PID controller so that parameters of the PID controller could be adjusted self-adaptively. To solve the problem that poor selection of initial parameters of RBFNN and PID might lead to overshoot or instability in the control system, PSO is adopted to optimize aforementioned initial parameters off-line. Finally, a closed-loop adaptive control system model is built in MATLAB/Simulink. Simulation results show that …


Simulation And Analysis For Gaussian Jitter Effects Of Geosynchronous Satellite, Yulun Li, Yang Wei, Jiayi Guo Feb 2021

Simulation And Analysis For Gaussian Jitter Effects Of Geosynchronous Satellite, Yulun Li, Yang Wei, Jiayi Guo

Journal of System Simulation

Abstract: Ultrahigh-spatial-resolution and high-temporal-revisit appear to be realizable for future space-borne imaging missions. By taking advantage of satellites on the geosynchronous orbit, the wide-area continuous monitoring capacity to ground target zones becomes possible. Focus on the imaging target displacement, it is necessary to study the platform jitter during the conceptual modeling phase. Discrete Event System Specification (DEVS) is employed to abstract the observation area as an event generator. The attitude stabilization is digitalized and both theoretical analysis and simulation experiments of Gaussian-excited signals are provided. Simulation results show that the distributions of attitude responses preserve the normality. The offset distance …


A Quantized State System Method With Adaptive Quantum, Zhihua Li, Dongjin Fu, Li Guang, Zhihua Fan Feb 2021

A Quantized State System Method With Adaptive Quantum, Zhihua Li, Dongjin Fu, Li Guang, Zhihua Fan

Journal of System Simulation

Abstract: Quantized state system (QSS) is a new numerical integration method. It has advantages over the traditional time-discrete integration methods in solving general ordinary differential equation (ODE) systems. But it is hard to choose an appropriate quantum for the QSS method. In order to improve the accuracy and efficiency of QSS, a quantized state system method with adaptive quantum (VQSS) is proposed. Combined with the idea of step control in the variable step Runge-Kutta method, it can adaptively change the quantum in the process of computation. The feasibility of this algorithm is verified by the simulation of two examples …


Visualization Of Tropical Cyclone Disaster Information Based On Cesium, Shuoben Bi, Yezhou Chen, Yucheng Gong, Mingyue Lu, Ruizhuang Xu Feb 2021

Visualization Of Tropical Cyclone Disaster Information Based On Cesium, Shuoben Bi, Yezhou Chen, Yucheng Gong, Mingyue Lu, Ruizhuang Xu

Journal of System Simulation

Abstract: The disaster information of tropical cyclones not only expresses the intensity, but also reflects the degree of influence on human life, which has very important research significance. At present, no scholar has given a dynamic visualization method based on Cesium for water flooding disasters, nor has it integrated with other disaster information of tropical cyclones. In response to these problems, a dynamic visualization method for water inundation is proposed, and it is integrated with other disaster information such as the path of tropical cyclone and loss caused by it in the same digital earth platform. Experiments show that the …


Negative Influence Minimization Algorithm For Social Networks, Yang Yi, Chunxiao Wu, He Ming, Zhou Bo Feb 2021

Negative Influence Minimization Algorithm For Social Networks, Yang Yi, Chunxiao Wu, He Ming, Zhou Bo

Journal of System Simulation

Abstract: While positive information is spreading in social networks, there is still a large amount of negative information spreading in the network. Aiming at the fact that there is few researches on suppressing the spread of negative information, a negative influence minimization algorithm for social networks is proposed. When negative information appears in social networks and some initial nodes are infected, the behavior of nodes propagating information depends on its coordination game with neighbor nodes. The objective function with minimal influence is used to find the K optimal blocking nodes, and finally the size of the final infected node is …


Spatio-Temporal Memory Models In Spatial Cognitive Behavioral Modeling, Hu Yue, Xu Kai, Qin Long, Quanjun Yin, Yabing Zha Feb 2021

Spatio-Temporal Memory Models In Spatial Cognitive Behavioral Modeling, Hu Yue, Xu Kai, Qin Long, Quanjun Yin, Yabing Zha

Journal of System Simulation

Abstract: It is crucial for military simulation systems to model the layouts of spatial environments and the temporal logic of entity activities. To improve the human-likeness of Computer Generated Forces (CGFs) and the runtime efficiency of the systems, building spatio-temporal memory representations and reasoning mechanisms that accord to mankind cognition is required. The neuro cognition science background of spatio-temporal memory is presented, and the related work on modeling the memory in deep learning and computational intelligence communities is summarized. Following the OODA (Observe-Orient-Decide-Act) loop, a general framework of spatial cognitive behavioral modeling is designed and the application of spatio-temporal memory …


Research On Cgf-Oriented Virtual Human Perceptual Attention Model, Weilong Yang, Xu Kai, Xie Xu, Sun Lin Feb 2021

Research On Cgf-Oriented Virtual Human Perceptual Attention Model, Weilong Yang, Xu Kai, Xie Xu, Sun Lin

Journal of System Simulation

Abstract: Perception model is an important research field of CGF behavior modeling. As the input of the reasoning module, the information obtained from the perception model has an important influence on the fidelity of the simulation. The CGF perception model is researched, and the attention mechanism, effective time of attention model is analyzed, compared with the traditional model of perception. By modeling the knowledge base and information feedback, a virtual human perception framework based on attention mechanism is proposed, and the experiment is carried out in the simulation environment.


Review On The Construction And Application Of Digital Twins In Transportation Scenes, Zhaohui Wu, Zhenzheng Liu, Shi Ke, Wang Liang, Xiaojie Liang Feb 2021

Review On The Construction And Application Of Digital Twins In Transportation Scenes, Zhaohui Wu, Zhenzheng Liu, Shi Ke, Wang Liang, Xiaojie Liang

Journal of System Simulation

Abstract: Digital twins connect the physical world and the information world, and provide new ideas for the analysis and solution of complex traffic problems. The research and application status of digital twins in transportation scenes are reviewed on the basis of sorting out the basic concepts, development history and key technologies of digital twins. The key technologies for the construction of digital twins in transportation scenes that need to be breakthrough are analyzed from the four aspects of "people-vehicle-road-environment" combined with the characteristics of the elements of traffic operation. The prospect of digital twin transportation applications in the development of …


Sliding Mode Adaptive Synchronization Control Dual Master Dual Slave Teleoperation System, Lingyan Hu, Shiqiang Li, Fu Yun Feb 2021

Sliding Mode Adaptive Synchronization Control Dual Master Dual Slave Teleoperation System, Lingyan Hu, Shiqiang Li, Fu Yun

Journal of System Simulation

Abstract: Aiming at the relative coordinated motion of the two-slave arms' end poses in the dual-master dual-slave teleoperation system, the influence on the coordinated positional relationship of the two slaves is analyzed when one of the master-slave controls is disturbed. A feasible synchronous position control method is propose which enables both the master-slave position error and the synchronization error of the dual master dual slave remote operating system to converge to zero during the coordinated motion When the master-slave arm moves along the desired trajectory, the coordination and synchronization of the movement between the two slave arms are ensured, and …


Simulation Experiment Of Quantum Ranging Process Based On The “Mozi” Quantum Satellite, Cong Shuang, Shiqi Duan Feb 2021

Simulation Experiment Of Quantum Ranging Process Based On The “Mozi” Quantum Satellite, Cong Shuang, Shiqi Duan

Journal of System Simulation

Abstract: The simulation experiment researches about two key processes of earth-satellite quantum ranging process are carried out, including the transmission and reception about the photon pairs based on the acquisition, tracking and pointing (ATP) system, and the calculation about the time difference of arrival (TDOA) of entangled photon pairs by the coincidence counting principle. Motion trajectory of the quantum satellite “Mozi” based on its six orbital parameters and the acquisition, tracking and pointing process to the optical signal from satellite to ground users are simulated. The function and structure of the acquisition tracking and pointing system are analysed, and a …


Ar-Based Simulation Interaction And Human Factor Assessment For Human Robot Cooperation Assembly Planning, Wang Qiang, Xiumin Fan, Qichang He, Wenmin Zhu Feb 2021

Ar-Based Simulation Interaction And Human Factor Assessment For Human Robot Cooperation Assembly Planning, Wang Qiang, Xiumin Fan, Qichang He, Wenmin Zhu

Journal of System Simulation

Abstract: To improve assembly efficiency, it has become a trend for traditional manual assembly workstations to be carried out human-robot collaboration transformation. To realize the safe and fast evaluation of the improvement scheme, a general human-robot collaboration simulation method and human factor evaluation method based on Augmented Reality are proposed. Four levels of human-robot collaboration assembly simulation are established. An interactive scheme between real human and virtual robot for visual detection, perception and feedback is established. A fuzzy comprehensive evaluation model of human physiological and psychological indicators for workstation design is constructed. The prototype system is developed. Taking the assembly …


Infrared Image Segmentation Of Aircraft Skin Based On Otsu And Improved I-Ching Divination Evolutionary Algorithm, Kun Wang, Ji Yao, Peilun Liu, Wang Li Feb 2021

Infrared Image Segmentation Of Aircraft Skin Based On Otsu And Improved I-Ching Divination Evolutionary Algorithm, Kun Wang, Ji Yao, Peilun Liu, Wang Li

Journal of System Simulation

Abstract: Infrared thermal imaging non-destructive testing is one of the commonly used methods for aircraft skin detection. Aiming at Otsu's large computational complexity and poor real-time performance, an aircraft skin infrared image segmentation method based on Otsu and an improved I-Ching divination evolutionary algorithm (IDEA) is proposed. The roulette selection operator is improved by using roulette selection for the I-Ching map of state size 3n, from which the n individuals with the maximum fitness values are then selected as new populations. The experimental results show that the proposed algorithm is superior to several other improved optimization algorithms both in terms …


Simulation Of Adaptive Track Control Of Ship Bending In Inland River Curved Channel, Langxiong Gan, Changsheng Wu, Deng Wei, Yuanzhou Zheng, Chunhui Zhou Feb 2021

Simulation Of Adaptive Track Control Of Ship Bending In Inland River Curved Channel, Langxiong Gan, Changsheng Wu, Deng Wei, Yuanzhou Zheng, Chunhui Zhou

Journal of System Simulation

Abstract: In view of the complex flow characteristics and difficult maneuvering of ships in curved river section, combined with the characteristics of ship AIS trajectory and customary route, the intelligent track and heading control algorithm is adopted to realize the automatic control of ship's safe turning. Firstly, the research waters are selected and according to the rules of lane-dividing navigation, the ship's turning track is reasonably planned. Then the ship motion simulation software is constructed, and the self-adaptive fuzzy PID course controller is designed by combining the self-adaptive fuzzy control algorithm and traditional PID control, the simulation of …


Correction Method Of Action Parameters Of Panzer Virtual Force Tactical Confrontation, Gao Ang, Xiaolu Wang, Zhiming Dong, Guohui Zhang Feb 2021

Correction Method Of Action Parameters Of Panzer Virtual Force Tactical Confrontation, Gao Ang, Xiaolu Wang, Zhiming Dong, Guohui Zhang

Journal of System Simulation

Abstract: Aiming at the problem of unreasonable virtual force tactical confrontation action parameters in the simulation training of armored force equipment system, resulting in unsatisfactory training effects, the idea of estimating posterior probability with prior probability is adopted to correct the parameters. According to the OODA theory, the tactical confrontation movement of armored forces is decomposed and an index system of influencing factors is constructed; the parameter collection method is proposed to establish the Bayesian network correction model and to realize dynamic adjustment; the expected optimization algorithm and the principal component analysis method are used to process the training data …


Modulation Recognition Algorithm Based On Improved Lda And Autoencoders, Yecai Guo, Haoran Zhang Feb 2021

Modulation Recognition Algorithm Based On Improved Lda And Autoencoders, Yecai Guo, Haoran Zhang

Journal of System Simulation

Abstract: The traditional modulation recognition algorithms are based on the Gaussian white noise channel, which significantly degrade recognition performance in complex channel conditions. Aiming at this problem, a modulation recognition algorithm based on A-ALDA (Anti-alias Linear Discriminant Analysis) and SSDAE (Stacked Sparse Denoising Autoencoders) is proposed. In this algorithm, A-ALDA algorithm reconstructs signal cumulants feature into new features, which has better separability. The combination of original features and new features is input into SSDAE for classification, and SSADE has the ability to extract key information and resist noise. Simulation results show that …


Improved Wolf Pack Algorithm For Distribution Of Molds On Molds Table, Zhonghua Han, Yuehan Liu, Li Man, Liangliang Sun, Hongzhi Zheng Jan 2021

Improved Wolf Pack Algorithm For Distribution Of Molds On Molds Table, Zhonghua Han, Yuehan Liu, Li Man, Liangliang Sun, Hongzhi Zheng

Journal of System Simulation

Abstract: In order to solve the problem of the distribution of molds on the mold table in the production process of concrete prefabricated components, a method combining Bottom-Left Algorithm (BLA) and Improved Wolf Pack Algorithm (IWPA) is proposed. Improved Wolf Pack Algorithm is for optimizing the order of upper line and the mold used for each member is sequentially assigned to the mold table according to the upper line. BLA is used to determine the direction and position of the molds on the molds table. The WPA safari behavior is improved by introducing Levi's flying ideas and the Hamming …


Simulation Research On Abandonment Rate Of Contact Center Based On Patience Threshold, Junxiang Li, Wanbin Zang Jan 2021

Simulation Research On Abandonment Rate Of Contact Center Based On Patience Threshold, Junxiang Li, Wanbin Zang

Journal of System Simulation

Abstract: Customer abandonment rate is an important indicator to measure the service level of contact center. Customers in a traditional call center follow the principle of first come, first served, but some customers will be lost in the queuing process because of their limited patience. In this regard, by setting the customer's patience threshold and considering adding a specific agent channel to the member customers, or adjusting the number of agent channels under the original staffing, a new contact center queuing model is established based on the traditional call center model. The ProModel simulation software is used to study the …


Research On Virtual Simulation Training System For Multi-Position Collaborative Operation In Oilfields, Xianmei Liu, Jia Di, Liu Fang Jan 2021

Research On Virtual Simulation Training System For Multi-Position Collaborative Operation In Oilfields, Xianmei Liu, Jia Di, Liu Fang

Journal of System Simulation

Abstract: Aiming at the demands of multi-position collaborative operation in oilfields, the virtual simulation training system for multi-position collaborative operation in oilfields is studied. It shows the development mode and architecture of the system which uses the user perception environment to obtain data for the autonomous decision, and uses the collision detection process to simulate the interaction between user and device. The co-simulation strategy and the network communication protocol are designed. The room management is used to ensure that the scenes in the group are consistent in real time and the scenarios between the groups are independent. The Non-Player Character(NPC) …


Study On Ultimate Carrying Capacity And Regulation Methods Of Urban Atmospheric Environment, Guangqiu Huang, Wenxin Wang Jan 2021

Study On Ultimate Carrying Capacity And Regulation Methods Of Urban Atmospheric Environment, Guangqiu Huang, Wenxin Wang

Journal of System Simulation

Abstract: In order to solve the calculation problem of the ultimate carrying capacity of the atmospheric environment, the calculation formula of the ultimate carrying capacity of the atmospheric environment is proposed, and the system dynamics model with the ‘pollution index-energy' compliance as the constraint is constructed according to the urban energy planning, namely the PI-E-SD(Pollution Indicator-Energy-System Dynamics) model. In this model, the linear regression method is used to determine the pollution index, which solves the non-uniformity problem. The SD-modeling method is used to construct the “energy-economy-environment” simulation system, so that the government measures can be quantified to make the prediction …


Traversal Path Planning And Simulation Of Robot Based On Radiation Scanning, Bin Lin, Guanghui Han, Chenchen Song, Yajing Zhang Jan 2021

Traversal Path Planning And Simulation Of Robot Based On Radiation Scanning, Bin Lin, Guanghui Han, Chenchen Song, Yajing Zhang

Journal of System Simulation

Abstract: Aiming at the high repetition rate and many turns of robot paths based on BINN algorithm, an ITPPA combining the template model and the RS algorithm is proposed. The BINN algorithm is used to formulate the non-obstacle walking strategy. Multiple obstacle avoidance path templates are designed to ensure that the robot could avoid obstacles in an orderly manner. RS algorithm is used to guide the robot to escape the dead zone quickly. Simulation results show that, compared with BINN algorithm, ITPPA could not only effectively reduce the path repetition rate and the number of turning and energy consumption …


Joint Low Rank And Sparsity-Based Channel Estimation For Fdd Massive Mimo, Zhou Jin Jan 2021

Joint Low Rank And Sparsity-Based Channel Estimation For Fdd Massive Mimo, Zhou Jin

Journal of System Simulation

Abstract: Channel estimation of millimeter wave communication needs large system load. In order to reduce the load, a low-rank and sparse feature of the wireless channel is combined, and a channel estimation algorithm framework based on non-convex low-rank approximation is proposed. Aiming at the large computation of the channel model-based dictionary learning algorithm, a dictionary learning algorithm for deep neural network channel feature classification is designed. The simulation shows that the average square error of the proposed method is better than the channel model-based dictionary learning method, the channel estimation method under the Bayesian framework, and the compressed …


Research On Precision Parking Control Method For Emu Inbound Process, Zhongqi Li, Yueshuang Xing Jan 2021

Research On Precision Parking Control Method For Emu Inbound Process, Zhongqi Li, Yueshuang Xing

Journal of System Simulation

Abstract: By analyzing the relationship between braking force and speed during the stop-stop process of high-speed EMU(Electric Multiple Units), the multi-point dynamics model of EMU is constructed. The Smith predictor is introduced due to the delay effect on the system caused by the braking force generated during the late braking, and the RBF(Radial Basis Function) neural network-based PID control strategy is combined with the Smith predictor to achieve tracking control of a given speed during braking. Simulation analysis shows that the error of train speed and set speed controlled by RBF neural network PID-Smith controller is less than ±1 …


Overview Of Optimization Problems Regarding Emergency Organization Allocation Based On Mathematical Programming, Cejun Cao, Congdong Li Jan 2021

Overview Of Optimization Problems Regarding Emergency Organization Allocation Based On Mathematical Programming, Cejun Cao, Congdong Li

Journal of System Simulation

Abstract: To improve the utilization of human resources in large-scale natural disasters and reduce various losses, how to use mathematical programming approach to optimize emergency organization allocation strategy is the currently urgent and critical issue. A decision framework or conceptual model for emergency organization allocation optimization is proposed. The current status of mathematical programming model for emergency organization allocation is presented from the perspective of task sequence and objective quantity. An overview on the exact and heuristic algorithm to solve the proposed model is conducted. Potential issues for in-depth study with respect to simulation and modeling of emergency organization allocation …


Uncertainty Quantitative Analysis In Risk Assessment Of Returning To School In The Post-Covid-19 Era, Haibin Li, Jialiang Wang, Haiyan Li Jan 2021

Uncertainty Quantitative Analysis In Risk Assessment Of Returning To School In The Post-Covid-19 Era, Haibin Li, Jialiang Wang, Haiyan Li

Journal of System Simulation

Abstract: After the epidemic, taking the spread of the epidemic in returning to school as an example, a quantitative risk assessment study is conducted. Taking the activity trajectory description of the whole process of susceptible individuals from infection to isolation as a clue, an epidemiological model for risk assessment is established. The number of infected persons in the risk indicators of returning to school is quantified based on the quantified model parameters. According to the value characteristics of the parameters, the number of infected persons is taken as a function of discrete random variables. The probability distribution of the infected …