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2020

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Articles 1141 - 1170 of 1494

Full-Text Articles in Systems Science

Wormhole Attack Detection Scheme Design In Zigbee Network, Yanqing Shi, Chen Wei, Bin Yu Jun 2020

Wormhole Attack Detection Scheme Design In Zigbee Network, Yanqing Shi, Chen Wei, Bin Yu

Journal of System Simulation

Abstract: Wormhole attacks destroy the network topology, routing discovery and resource allocation in ZigBee network. A wormhole attack detection scheme was proposed, based on the definition of wormhole node, explicit wormhole node and implicit wormhole node. The scheme marked wormhole nodes by judging the matching between neighborhood and communication radius. On this basis, the scheme designed a type recognition mechanism of wormhole nodes. Safety analysis and experiment results show that the scheme detects wormhole attacks effectively with low communication overhead and computation cost.


Research On Power/Electrical Integrated Simulation Platform Of Nuclear Power Plant Based On Pscad, Ye Peng, Qin Wei, Teng Yun, Yaoning Hu Jun 2020

Research On Power/Electrical Integrated Simulation Platform Of Nuclear Power Plant Based On Pscad, Ye Peng, Qin Wei, Teng Yun, Yaoning Hu

Journal of System Simulation

Abstract: Nuclear power plant (NPP) has the characteristics such as complex internally operation, being sensitive to power network changing and large mathematical models. According to electromagnetic transient simulation platform PSCAD, an integrative simulation platform was established to reflect power regulation characteristic in the power section of nuclear power plant (NPP) and the dynamic operation conditions when NPP was incorporated into power system. With the powerful dynamic control ability and abundant library elements of PSCAD, simulation results proved the power regulation capability in NPP. Disturbed capability analysis of NPP was made during the load-following process after NPP merges into power grid, …


Research On Panoramic Image Mosaic Method Based On Camera Calibration, Jialin Ma, Jinming Zhang, Weixin Sun Jun 2020

Research On Panoramic Image Mosaic Method Based On Camera Calibration, Jialin Ma, Jinming Zhang, Weixin Sun

Journal of System Simulation

Abstract: A panoramic mosaic method was proposed based on camera calibration, geometric distortion correction and rotation transformation processing was done for stitching image, in order to improve the accuracy of image registration and panorama stitching quality. The homography was acquired by calculating the camera linear calibration, and the inside and outside parameters of the homography were separated. The radial distortion of the image was calculated by the inside parameters, and the image geometric distortion was corrected; a sequence of images was transformed in the same world coordinates using the external parameters; image registration was achieved accurately though the same name …


Research On Simulation Of Emergency Evacuation Guidance Under Biochemical Terror Attacks, Sui Jie, Shengjie Long Jun 2020

Research On Simulation Of Emergency Evacuation Guidance Under Biochemical Terror Attacks, Sui Jie, Shengjie Long

Journal of System Simulation

Abstract: Biochemical terror attacks can cause numerous casualties, especially when it happens in public places such as subway station, which is densely populated, sealed, and complex in topography. And evacuating guidance plays an important role in reducing casualties. A guidance scheme was established based on both evacuating empirical formula and passengers escaping rules, according to evacuation problems in subway station. Meanwhile, the different features of passengers and their behaviors under attack were analyzed, as well as their impacts on evacuation. By simulating various evacuation situations based on social force simulation model, the importance of environmental features and passengers features in …


Fractional Modeling And Simulation Analysis Of Single-Phase Pwm Rectifier, Zheng Zheng, Fangjun Ma, Yanfang Wei Jun 2020

Fractional Modeling And Simulation Analysis Of Single-Phase Pwm Rectifier, Zheng Zheng, Fangjun Ma, Yanfang Wei

Journal of System Simulation

Abstract: The modeling problem of single-phase PWM rectifier was studied, based on the fact that actual capacitance and inductance is the fractional in nature. The mathematical model of single-phase PWM rectifier was established by using fractional calculus theory, based on modeling method analysis of fractional Caputo definition and PWM rectifier topology. According to instantaneous power theory, for DC component value, the peak to peak value AC component, and the time of dynamic response of the DC side capacitor voltage were analyzed. In theory, DC component value does not change with the order number capacitance, while the AC component is opposite, …


System Modeling And Simulation For Cylinder Controlled By Servo Valve Of Hydraulic Looper In Hot Strip Mills, Guilin Tao, Weigang Li Jun 2020

System Modeling And Simulation For Cylinder Controlled By Servo Valve Of Hydraulic Looper In Hot Strip Mills, Guilin Tao, Weigang Li

Journal of System Simulation

Abstract: Starting from the flow characteristics of cylinder controlled by servo valve of hydraulic looper in hot strip mills, a new mathematic model for hydraulic cylinder controlled by servo valve was established by analyzing and deducing the flow characteristics of two chambers of hydraulic cylinder. The model is different from the traditional equivalent model of “load-pressure flux”, and it is adaptable to many structural forms such as symmetric cylinder, asymmetric cylinder and piston cylinder. The simplified equivalent model was deduced by the simplified method of automatic control principles. The simulation experiments were carried out on a practical cylinder controlled …


Trajectory Optimization And Tracking Controller Based On Gauss Pseudo Spectral Method For Hypersonic Vehicle, Tao Chao Jun 2020

Trajectory Optimization And Tracking Controller Based On Gauss Pseudo Spectral Method For Hypersonic Vehicle, Tao Chao

Journal of System Simulation

Abstract: For a complex nonlinear mass dynamic model in the ascent stage for a hypersonic vehicle with multiple constrains including state constrains, control constrains, boundary constrains and path constrains, a trajectory optimization methodology based on Gauss Pseudo Spectral was proposed for the hypersonic vehicle. The optimal controller of the trajectory optimization results was chosen as the reference command. For the rigid body dynamics of the hypersonic vehicle, a nonlinear dynamic inverse control combined with PD control methodology was proposed to track the reference command. The simulation results demonstrate that, for the minimum fuel consuming trajectory optimization of the ascent …


Frequency Diverse Array Radar For Range-Angle Estimation Based On Difference Co-Array, Huang Ling, Zhiming He, Li Xiang, Yang Fan Jun 2020

Frequency Diverse Array Radar For Range-Angle Estimation Based On Difference Co-Array, Huang Ling, Zhiming He, Li Xiang, Yang Fan

Journal of System Simulation

Abstract: Because of the coupling in range and angle responses, which could not estimate directly both the range and angle information of a target, a sub-array scheme of distance-angle joint estimation of a target for frequency diverse array (FDA) radar was proposed. The entire array was divided into two subarrays, which employed two different frequency offsets. For aperture extension, each subarray adopted difference co-array structure to provide O(N2)degrees of freedom by only N physical sensors when the second-order statistics of the received data was used. Therefore, the targets range and angle could be estimated directly …


E-Learner's Emotion Regulation Model With Undirected Gaussian Graphical Model, Jiwei Qin, Turgun· Ibragim, Huiguo Zhang Jun 2020

E-Learner's Emotion Regulation Model With Undirected Gaussian Graphical Model, Jiwei Qin, Turgun· Ibragim, Huiguo Zhang

Journal of System Simulation

Abstract: Based on the absence of emotion in the background, e-Learner's emotion regulation model with simple variable can't fit the sparse and complex data in e-Learning, an e-Learner's emotion regulation model was proposed by Undirected Gaussian Graphical Model, which emphasized on many kinds of factor influences in emotion regulation. Correlation analysis, statistics, Gaussian undirected graph model fit the data to understand the relationship between data variables by using Chow-Liu algorithm, which searched for the smallest BIC forests and built e-learner's emotion regulation model based on the e-Learner's log. This model gives a basis for emotion regulation in e-Learning.


Study On Nonlinear Characteristics Of Buck-Boost Converter In Pulse Input Voltage, Xiaoqiu Li, Xiaoping Zhang Jun 2020

Study On Nonlinear Characteristics Of Buck-Boost Converter In Pulse Input Voltage, Xiaoqiu Li, Xiaoping Zhang

Journal of System Simulation

Abstract: To study on the nonlinear characteristics of the Buck-Boost converter in pulse input voltage, the nonlinear model with discrete and iterative was deduced, and the bifurcation and chaos diagram that reflected the output voltage of the converter changes with the inductance, capacitance and resistance respectively was obtained, which analyzed the bifurcate and chaotic phenomena of the converter, and at the same time, compared with that in the DC input voltage. The results show that, in a steady state the variation range of bifurcation parameter of the converter in the pulse input voltage is smaller and is earlier to get …


Study Of Crowd Evacuation In Two-Story Teaching Building, Xuefeng Zhang, Chenxi Bai Jun 2020

Study Of Crowd Evacuation In Two-Story Teaching Building, Xuefeng Zhang, Chenxi Bai

Journal of System Simulation

Abstract: In order to study the multi-level building evacuation problem, visual perception and communication exchange of personnel model was achieved based on the Delegate/Event mechanism and Multi-agent technology, moreover, which set in two-story teaching building. Considering about the extent of the familiar environment, physiological and psychological factors, a mathematical model of fire and visual perception model was established, analyzing the personnel evacuation under three fire scenarios exit, stairs and corridor, moreover, focusing on simulation of personnel evacuation behavior in the stairway. The experimental results show that this model can truly reflect the building evacuation in fire environment, which …


Woodcock Tracking Based Fast Monte Carlo Direct Volume Rendering Method, Shoudong Zhou Jun 2020

Woodcock Tracking Based Fast Monte Carlo Direct Volume Rendering Method, Shoudong Zhou

Journal of System Simulation

Abstract: Woodcock-Tracking sampling algorithm is a frequently applied ray sampling method, which plays an important role in optimizing the Monte Carlo direct volume rendering method. However, without considering the volume of color's variation in different region by using this method, the situation that region with great color's variation may only get a few samples was caused and the authenticity of volume data would be affected. Entropy to indicate color's variation in volume was introduced, an entropy based adaptive Woodcock-Tracking method was developed, which could sample more points in region with higher color's variation. To overcome biases caused by adaptive Woodcock-Tracking …


Coordinated Control Of Power System Based On Direct Neural Dynamic Programming Method, Yu Miao, Weipeng Shang, Lu Ning Jun 2020

Coordinated Control Of Power System Based On Direct Neural Dynamic Programming Method, Yu Miao, Weipeng Shang, Lu Ning

Journal of System Simulation

Abstract: Inter-area low frequency oscillation with weak damping is a key issue affecting the security and stability operation of power grid. Currently, the implementation of wide-area DC and generator control has become one of the important means to improve inter-area low frequency oscillation damping. But the coordination among the controllers of generator, HVDC and FACTS needs to further studying. The application structure of direct neural dynamic programming method in power system stability control was proposed, and based on phase-shift neural network of general lead-lag link, the proposed method was embedded in the traditional power system stability controller. It was applied …


Pedestrian Flow Simulation Model Based On Potential Grid And Its Application To Lane Formation Phenomenon, Le Fang, Xuefu Jin, Siyuan Wang, Wang Ying Jun 2020

Pedestrian Flow Simulation Model Based On Potential Grid And Its Application To Lane Formation Phenomenon, Le Fang, Xuefu Jin, Siyuan Wang, Wang Ying

Journal of System Simulation

Abstract: By combining macro characteristics in fluid mechanics model and micro characteristics in social force model together, and using Dijkstra algorithm to establish a potential function covering the whole field of simulation, with the guidance of Smoothed Particle Hydrodynamics, a new model was created in order to keep both macroscopic and microscopic characteristics during the process of simulation. This new model was verified by evacuation simulation in a music hall. Using this model, lane formation phenomena was reproduced. The definition of lane formation ratio makes it possible to analyze variations and causes of this typical self-organization phenomena, providing us with …


Localization Method Based On Modified Cuckoo Difference Optimization For Wireless Sensor Networks, Dengfeng Liu, Zhang Li, Xiaoying Bing, Yuqian Shao, Baoguo Xu Jun 2020

Localization Method Based On Modified Cuckoo Difference Optimization For Wireless Sensor Networks, Dengfeng Liu, Zhang Li, Xiaoying Bing, Yuqian Shao, Baoguo Xu

Journal of System Simulation

Abstract: To solve the sensitive and accumulative ranging error issue in the trilateration method and the maximum likelihood estimation method for the DV-Hop localization algorithm, an algorithm based on the Cuckoo difference optimization was proposed. The proposed algorithm essentially turned the positioning calculation problem into a group optimization problem. Using the Cuckoo algorithm and the differential evolution algorithm for parallel optimization with double populations, the proposed algorithm fused the advantages of the two kinds of intelligent optimization algorithms, which dynamically rectified the abandoned factor and the scaled variation factor randomly at the same time. The Cuckoo differential evolution algorithm's global …


Modeling And Simulation Of Marine Traffic Macroscopic Flow Complexity, Yuanqiao Wen, Du Lei, Yamin Huang, Tengda Sun, Changshi Xiao, Chunhui Zhou Jun 2020

Modeling And Simulation Of Marine Traffic Macroscopic Flow Complexity, Yuanqiao Wen, Du Lei, Yamin Huang, Tengda Sun, Changshi Xiao, Chunhui Zhou

Journal of System Simulation

Abstract: To accurately describe the difficulty of cognitive traffic in the view of traffic managers, a method for quantitative calculation of marine traffic macroscopic flow complexity was proposed. The similar ships were cataloged into a traffic cluster; According to the historical traffic flow field by interpolation method, the aggregation complexity, the speed-diachronic complexity and the density-diachronic complexity were evaluated. The cognitive complexity was obtained by the marine traffic macroscopic flow complexity, showing the cognitive complexity in the macroscopic complexity map. The simulation experiment shows the macroscopic complexity model is available for demonstrating the distribution of complexity in space.


Research On New Equalization Strategy For Series-Connected Battery Strings Based On Soc, Jianlong Huang, Tinglong Pan, Dinghui Wu Jun 2020

Research On New Equalization Strategy For Series-Connected Battery Strings Based On Soc, Jianlong Huang, Tinglong Pan, Dinghui Wu

Journal of System Simulation

Abstract: The adjacent cells comparing strategy has a low energy transfer efficiency, and the MAX/MIN value strategy has a slow equalization speed. Then, a new equalization strategy was proposed to overcome above disadvantages, and the uniform of the SOC of the battery strings was used as the equalization goal in this strategy. The strategy used the estimation of the average balanced SOC as a reference, and controlled the switch states and the energy transfer direction of each equalizer, according to the energy distribution of the entire battery strings. With this strategy the unnecessary energy loss during energy transfer was reduced …


Cohesion Based Algorithm To Manage Ids Alerts, Jinlei Huang, Hengjun Wang, Bin Yu Jun 2020

Cohesion Based Algorithm To Manage Ids Alerts, Jinlei Huang, Hengjun Wang, Bin Yu

Journal of System Simulation

Abstract: On the basis of intrusion taxonomies and semantic similarity, the concept of cluster cohesion as well as an algorithm was proposed to manage IDS alerts. Based on cohesion, the proposed approach used improved bisecting K-means to aggregate massive alerts, and extracted the abnormal alerts from clusters formed in aggregation. The experimental results show that the approach is effective in alerts aggregation and abnormal alerts detecting, and can generate understandable meta-alerts with higher accuracy.


Ble Key Agreement Scheme Based On Rssi Variation Trend, Xinghao Zhang, Yicai Huang, Bin Yu Jun 2020

Ble Key Agreement Scheme Based On Rssi Variation Trend, Xinghao Zhang, Yicai Huang, Bin Yu

Journal of System Simulation

Abstract: Based on the variation trend of received signal strength index, a lightweight BLE key agreement scheme was proposed. Using adaptive frequency hopping, the variation of channel characteristics was strengthened. According to the randomness and reciprocity of BLE channel characteristics in coherence time, the RSSI of BLE signal was measured. And the real-time key was produced by calculating the variation trend. On the basis of experiments results, the randomness of key can be ensured, and a high key generation rate has been reached at the same time. The scheme can be applied to resource-constrained applications.


Motion Analysis And Simulation Of Lower Limb Based On Adams, Zhang Yan, Haomiao Zhang, Bokai Xuan, Yongchang Zhang Jun 2020

Motion Analysis And Simulation Of Lower Limb Based On Adams, Zhang Yan, Haomiao Zhang, Bokai Xuan, Yongchang Zhang

Journal of System Simulation

Abstract: On the basis of the lower limb movement kinematics and dynamics analysis, a lower limb motion simulation system was established by the virtual prototyping technology. The human model was designed by ADAMS and the angle and moment of force in each joint were obtained through kinematics and dynamics analysis. The established model of lower limb was validated by the simulation of human lower limb movement under different road conditions. The experiment result shows that the walking process of each road conditions are stable and normal. It indicates that the virtual prototype model can accurately describe the process of human …


Modeling And Simulation Of Single Lane Taxi Boarding System Based On Queuing Theory, Sun Jian, Rijia Ding, Yanyan Chen Jun 2020

Modeling And Simulation Of Single Lane Taxi Boarding System Based On Queuing Theory, Sun Jian, Rijia Ding, Yanyan Chen

Journal of System Simulation

Abstract: Taxi pick-up area was described as a queuing system based on the GPSS language to establish a simulation model, to find out a new way to improve taxi traffic capacity. Vehicle release officer and passenger release officer were represented by logic switch object, such business logic as taxi producing, taxi entering, boarding, taxi leaving could be reappeared well in computer. The time which spent on the above processes were analysed and by video data. Multi wheel simulation experiments were carried out. Quantitative analysis was executed to find out how the traffic capacity are affected by the berth quantity and …


Research On Network-On-Chip Synthesis Flow Based On Hybrid Optimization Mapping Algorithm, Junyi Li, Yijun Liu, Le Jianliang Jun 2020

Research On Network-On-Chip Synthesis Flow Based On Hybrid Optimization Mapping Algorithm, Junyi Li, Yijun Liu, Le Jianliang

Journal of System Simulation

Abstract: To solve the problem of particle swarm optimization algorithm, which is easy to fall into local optimum in network on chip mapping, a hybrid optimization mapping Algorithm based on particle swarm optimization and genetic algorithm was proposed. It implemented GA and PSO separately with two groups, by the superior individuals from GA algorithm instead of the initial random particles from PSO algorithm, which not only maintained the diversity of the group but also improved search efficiency. Simulation results based on NS-2 show that the Network-on-Chip from the automatic generation tools have a good performance in network latency, throughput, and …


Estimation Of Atmospheric Parameter Based On Airflow Velocity Over Wing Leading Edge, Lilin Qian, Jianwu Tao, Yueming Yang, Yu Fei Jun 2020

Estimation Of Atmospheric Parameter Based On Airflow Velocity Over Wing Leading Edge, Lilin Qian, Jianwu Tao, Yueming Yang, Yu Fei

Journal of System Simulation

Abstract: A new method measuring the atmospheric parameters was proposed based on acoustic vector sensors located at the wing leading edge, and the atmospheric parameters model was set up based on the airflow velocity distribution sensed by acoustic vector sensor over wing leading edge. According to the symmetric, swept character of wings, velocity vector was decomposed to solve the non-linear equation of model. The expressions of angle of sideslip, angle of attack and free stream velocity were derived. The feasibility of the expressions was verified by wing simulation data from Fluent.


Online Optimal Control Method Of Conveyor-Serviced Batch Processing System, Wu Song, Tang Hao, Tan Qi Jun 2020

Online Optimal Control Method Of Conveyor-Serviced Batch Processing System, Wu Song, Tang Hao, Tan Qi

Journal of System Simulation

Abstract: In conveyor-serviced batch processing system, jobs arrive dynamically and are stored in a buffer to be further processed by the batch processing machine. Under the cases of non-identical job sizes, online optimal control of the system with a single machine was mainly concerned. Optimization model of the system was built by using look-ahead range as control variable. The objective is to maximize the job processing rate of the system in infinite horizon. Two decision processes are included in the model, which are batching process and action-selection process. For the batching process, the rule of minimizing process-capacity wasting ratio of …


Co-Design Between New Event-Triggered Communication Scheme And Less Conservative Robust H∞ Fault-Tolerant Control For Networked Control Systems, Li Wei, Pengfei Zhai, Yajie Li Jun 2020

Co-Design Between New Event-Triggered Communication Scheme And Less Conservative Robust H∞ Fault-Tolerant Control For Networked Control Systems, Li Wei, Pengfei Zhai, Yajie Li

Journal of System Simulation

Abstract: Based on the analysis for the disadvantage of the current discrete event-triggered communication schemes, a new kind of event-triggered communication scheme constrained by transient and stead-state process was proposed to perfect the conservatism and isolation of the fault-tolerant controller. A closed-loop failure model which was concerned with state-error was established for networked control system. Using the improved Wirtinger's inequality and the improved reciprocally convex combination inequality, the co-design between new event-triggered communication scheme and less conservative robust H∞ fault-tolerant control for networked control systems was focused on. The simulation results show that the new discrete event-triggered …


Simulation Of Ultrasonic Shear Wave Imaging In Detection Of Liver Rupture, Yu Jiao, Erwei Nie, Yanying Zhu Jun 2020

Simulation Of Ultrasonic Shear Wave Imaging In Detection Of Liver Rupture, Yu Jiao, Erwei Nie, Yanying Zhu

Journal of System Simulation

Abstract: Ultrasonic shear wave imaging technology provides the elastic information of the soft tissue by examining the propagation of the shear waves in the tissue. The possibility of using ultrasonic shear wave imaging technology combined with a directional filter for the detection of liver rupture was explored. The COMSOL Multiphysics software was used to simulate the generation and propagation of the shear waves in the liver medium with a rupture, a directional filter-based algorithm was applied to separate the incident wave and reflected wave, and an edge detection algorithm was applied to detect and delineate the liver rupture. Preliminary results …


Evaluation Method Research For Coal Mine Services Policy, Xue Xiao, Bin Gui, Yongmao Wang Jun 2020

Evaluation Method Research For Coal Mine Services Policy, Xue Xiao, Bin Gui, Yongmao Wang

Journal of System Simulation

Abstract: Mine service is the integration of the package which is based on a number of existing information system, the operation effect of service strategy directly determines the overall performance of the service system. However, due to the complexity of coal mine accidents and the special of mine environment, testing and evaluation of service strategy is very difficult in the actual environment. In order to solve this problem, an integrated evaluation method of coal mine service policy was proposed based on computational experiment. This method could be divided into three steps: the adaptive service strategy of service system in the …


Modeling Approach For Predictive Maintenance Scheduling Model Based On Variable Conversion, Mingyi You Jun 2020

Modeling Approach For Predictive Maintenance Scheduling Model Based On Variable Conversion, Mingyi You

Journal of System Simulation

Abstract: A modeling approach for predictive maintenance (PdM) scheduling model based on decision variable conversion was proposed. Based on the proposed approach, a PdM scheduling model could be established by replacing the time decision variable in the corresponding classical time-based preventive maintenance (PM) scheduling model with product condition variable(s) and checking the correlation of the model parameters, maintenance effect and maintenance constraints with product condition. Based on the proposed modeling approach, the application case study considered an unreported predictive maintenance model in which system benefit was correlated with its condition. The proposed approach used the existing PM scheduling …


Model For Multi-Area Interaction Control Based On User Strategy, Gong Bi, Bin Yu Jun 2020

Model For Multi-Area Interaction Control Based On User Strategy, Gong Bi, Bin Yu

Journal of System Simulation

Abstract: To solve the problem of multi-area interaction, a model based on user strategy was established. The structure of model was proposed according to security area and user strategy, and transfer path and relevant concept were put forward. The model was instantiated based on portable storage device, the multi-area interaction scene was set up, and the interaction controller structure was designed. Experiments were set up to simulate the host read/write memory process. By judging the host's read/write jurisdiction to memory partition and whether the transfer path can be arrived, the experimental results show that the model can realize interaction control …


Closed-Loop Feedback Simulation To Process Of Ram Blowout Preventer Shut-In Locking, Fangzhou Zhang, Ruixue Sun, Wenjing Zhang, Li Long, Li Qiang Jun 2020

Closed-Loop Feedback Simulation To Process Of Ram Blowout Preventer Shut-In Locking, Fangzhou Zhang, Ruixue Sun, Wenjing Zhang, Li Long, Li Qiang

Journal of System Simulation

Abstract: Well control training was explained mainly by teacher in recent years. Virtual simulation made it difficult for students to understand the actual operation. Application of drilling well control simulation training system solved effectively the problem of the scene seldom repetition and high cost of well control training. For the simulation of the process of ram blowout preventer shut-in locking in the well controlled physical simulation training system, the stepping motor driver and the stepping motor were installed in ram blowout preventer, and locking operation of the lock device was realized by using speed and torque of the stepping motor …