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2020

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Articles 1351 - 1380 of 1494

Full-Text Articles in Systems Science

Weld Trajectory Measurement Based On Stripe Type Laser Sensor, Li Lin, Weijie Chen, Yanbiao Zou Jun 2020

Weld Trajectory Measurement Based On Stripe Type Laser Sensor, Li Lin, Weijie Chen, Yanbiao Zou

Journal of System Simulation

Abstract: Teaching and playback are usually used on welding robot to weld a part. To make sure the implementation of this mode, it is needed to locate the part using artificial sport welding in the front process, which could cause location error and make the actual track deviate from the teaching track. A welding track offline detection device using stripe type laser sensor was proposed for solving the problem. The laser sensor was mounted at the end of the robot. The robot moved along the weld trajectory before welding. The information of the weld track section was gotten and the …

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Novel Power Control Algorithm For Cognitive Radio Network, Long Min, Juanjuan Lei Jun 2020

Novel Power Control Algorithm For Cognitive Radio Network, Long Min, Juanjuan Lei

Journal of System Simulation

Abstract: For the problems of near-far effect, large path loss, and stability of algorithm, etc., in the cognitive radio, a new power control algorithm was proposed. Utility function was improved effectively, where punishment factors, such as, link quality and the interference capacity limit of the primary users (PUs) were considered. Signal-to-interference radio (SINR) of cognitive users (CUs) was controlled above the minimum threshold, and the interference value of the CUs was controlled below the capacity tolerance of PUs. The existence of Nash equilibrium was given. Simulation results show that the new algorithm has better stability; the loss of path …

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Research On Feedback Compensation Control For Aircraft Electric Antiskid Brake System Based On Il, Gao Jie, Gao Bing, Jianying Liu Jun 2020

Research On Feedback Compensation Control For Aircraft Electric Antiskid Brake System Based On Il, Gao Jie, Gao Bing, Jianying Liu

Journal of System Simulation

Abstract: Safety, efficiency and comfort of aircraft are all determined by antiskid braking system. Because of the problem of inadequate control in the anti-skid braking system, the nonlinear model of the aircraft electric braking system was built by the analysis of aircraft landing process, and the iterative learning algorithm was introduced for reciprocating characteristics of anti-skid control. The groups in different speeds and road conditions were trained using the PD type learning rate. The knowledge base on the relationship among the optimal slip ratio and velocity and road conditions was built. The feed-forward control knowledge system for identifying the different …

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Survey Of Studies On Numerical Simulations Of Optical-Wave Propagation In Atmospheric Turbulence, Bin Ren, Chunyi Chen, Huamin Yang Jun 2020

Survey Of Studies On Numerical Simulations Of Optical-Wave Propagation In Atmospheric Turbulence, Bin Ren, Chunyi Chen, Huamin Yang

Journal of System Simulation

Abstract: The complicated random behavior of atmospheric turbulence makes it difficult to verify the theories of optical-wave propagation in atmospheric turbulence by conducting experimental measurements. The parameters used in numerical simulations can be easily controlled; therefore numerical simulations have been used as another important tool to investigate the optical-wave propagation in atmospheric turbulence. Based on the existing literature, both the theoretical models and numerical generating methods for random phase screens of atmospheric turbulence are surveyed, and the spatial sampling constraints for numerical simulations of optical propagation in atmospheric turbulence were summarized. By comprehending the existing results, it has been pointed …

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Genetic Algorithm For Solving Multi-Objective Dynamic Flexible Job Shop Scheduling, Wang Chun, Zhang Ming, Zhicheng Ji, Wang Yan Jun 2020

Genetic Algorithm For Solving Multi-Objective Dynamic Flexible Job Shop Scheduling, Wang Chun, Zhang Ming, Zhicheng Ji, Wang Yan

Journal of System Simulation

Abstract: To solve the scheduling problem of mold workshop in a toy factory with dynamic and flexible features, a mathematical model was established by introducing virtual operation and virtual working hours. Based on the strategies of periodic scheduling combined with dynamic event scheduling as well as the rolling window scheduling operation technology, dynamic scheduling was transformed into several continuous static scheduling windows, under which multi-objective genetic algorithm was used to solve the model. The priority of operation scheduling was given in different dynamic events. In addition, the encoding and anti-encoding of chromosome's operation sequence were made based on the proposed …

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Fast Tree Modeling Method Based On Simple Freehand Sketch, Ma Ling, Xiaoping Liu, Xiaoping Liu Jun 2020

Fast Tree Modeling Method Based On Simple Freehand Sketch, Ma Ling, Xiaoping Liu, Xiaoping Liu

Journal of System Simulation

Abstract: Aiming at problems such as complicated process and professional knowledge requirements in tree modeling, a quick tree modeling method for non-experts was proposed, combining branch library with simple sketch to make non-experts create tree model quickly. The method preprocessed the sketch to eliminate noise and error points and identify the strokes, the trunk and branch were reconstructed, child three-dimensional profile was built through the two-dimensional canopy profile, under the constraint of the child profile, suitable branches from library and insert were extracted into the branches, consequently the whole tree model was completed. Experimental results show that this method …

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Research On Natural Gas Explosion Rules For Cuboid Obstacles In Offshore Oil Platform, Pengcheng Wang, Yuqing Sun Jun 2020

Research On Natural Gas Explosion Rules For Cuboid Obstacles In Offshore Oil Platform, Pengcheng Wang, Yuqing Sun

Journal of System Simulation

Abstract: Quantities and blockage ratios of equipment on the platform has a great effect on the peak overpressure and temperature. The loss caused by explosion can be reduced to the minimum through the reasonable distribution of equipment, and the finite element method has been widely used in the simulation of gas cloud explosion. Offshore oil platform models with different cuboid obstacles were established by the finite element method and cuboid obstacles were distributed in 15 different situations. Mathematical relationships between overpressure and cuboid obstacles' quantities and blockage ratios were obtained. The results show that with the increase of quantities and …

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Research On Picking Robot Vision Localization Based On Semi-Physical Simulation, Keyin Chen, Xiangjun Zou, Hongxing Peng, Haiying Liang, Yuanchuang Hu Jun 2020

Research On Picking Robot Vision Localization Based On Semi-Physical Simulation, Keyin Chen, Xiangjun Zou, Hongxing Peng, Haiying Liang, Yuanchuang Hu

Journal of System Simulation

Abstract: Aiming at the problems of accuracy and stability of the vision localization based on physical picking robot, which were easy to make mistakes, long cycle, and not easy to be carried out indoors, a picking robot vision localization method based on the semi-physical simulation technology was proposed combining with the robot vision localization mechanism and robot kinematics. This method adopted the virtual picking robot to instead of the physical robot, and studied the vision localization of the fruit target in the virtual simulated environment, which was as the vision localization based on semi-physical simulation. The test results show that: …

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Improved Threshold Function Simulation Research In Vibration Signal Denoising, Hongxing Sun, Zhang Yang Jun 2020

Improved Threshold Function Simulation Research In Vibration Signal Denoising, Hongxing Sun, Zhang Yang

Journal of System Simulation

Abstract: Filtering noise component of mechanical vibration signal effectively can observe the characteristics of vibration signal more clearly. So based on the wavelet threshold de-noising method, a new improved threshold function was proposed. The coefficient of wavelet transform mechanical vibration signals were estimated by the threshold selection method based on kurtosis value. Not only new threshold function conforms to the distribution characteristics of the vibration signal, but also new threshold function is continuous in the threshold point. And the new threshold function overcomes the inherent deviation which traditional threshold function brings. The research of noise reduction on the simulation signal …

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Simulation And Analysis Of Ultra High Frequency Induction Heating Circuit Based On Current Source, Mangyuan Ma, Xinchun Shi, Wang Hui, Jianhui Meng Jun 2020

Simulation And Analysis Of Ultra High Frequency Induction Heating Circuit Based On Current Source, Mangyuan Ma, Xinchun Shi, Wang Hui, Jianhui Meng

Journal of System Simulation

Abstract: The operating frequency range, operating mode and output power are determined by the circuit. A suitable circuit is very important for induction heating power supply. On the basis of Class-E and Boost Chopper circuit, a new current source was analyzed with parallel resonant load circuit by energy conservation law and Fourier decomposition, which derived mathematical relation among the parameters and provided application theory. This circuit was studied by using Matlab/Simulink with variable parameters, which obtained the operating waves with different parameters and values. Comparing the operating waves with the theoretical analysis, the simulation results are completely consistent with the …

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Modeling Method Of Air Command And Security Work Process Service Oriented, Yongliang Luo, Yuanhui Qin Jun 2020

Modeling Method Of Air Command And Security Work Process Service Oriented, Yongliang Luo, Yuanhui Qin

Journal of System Simulation

Abstract: A modeling method of air command and security work process service oriented was proposed combined with the typical process equipment air command and support building requirements. Air command and process characteristics was analyzed systematically. On this basis, a complex process modeling method was proposed. From the concept of process meta-model, process formalized description mechanism was studied. A prototype flow modeling tool was developed, and the rationality of the proposed method was analyzed combined with the application example.

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Realistic Real-Time Road Rendering Technology Based On Road Boundaryalpha-Map, Jinlian Du, Shang Xin, Fengchao Zhao Jun 2020

Realistic Real-Time Road Rendering Technology Based On Road Boundaryalpha-Map, Jinlian Du, Shang Xin, Fengchao Zhao

Journal of System Simulation

Abstract: A method of realistic real-time rendering based on road boundary alpha-map was proposed to eliminate the blur and aliasing issues produced by traditional rendering method based on buffer mechanism. In the method, the road was generated by buffer mechanism based on grid model of terrain, and the road's borders were constructed by analyzing the characteristics of road boundary grids. Based on these, three types of road boundary alpha-maps were designed for producing the road borders with realistic visual effects. Experiment shows that the method can improve the rendering realism of the road borders than traditional method. Another advantage of …

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Simulation Modeling Method Of Distributed Supply Chain Based On Has, Wang Jian, Huang Yang Jun 2020

Simulation Modeling Method Of Distributed Supply Chain Based On Has, Wang Jian, Huang Yang

Journal of System Simulation

Abstract: There are some shortcomings in simulation modeling method of distributed supply chain based on High Level Architecture (HLA) and Supply Chain Operation Reference (SCOR), which result in low development efficiency of system simulation modeling and low reusability of simulation objects inside the federates. To solve the problems, a simulation modeling method of distributed supply chain based on HAS(HLA-Agent-SCOR) was put forward. The supply chain structure modeling based on HLA for building structure model of supply chain was discussed. Modeling of Agent blocks integrating processes from SCOR and modeling of federates based on Agent were illustrated to create model of …

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Trajectory Capture And Sway Frequency Analysis Of Trees Based On Kinect, He Peng, Shaojun Hu, Dongjian He Jun 2020

Trajectory Capture And Sway Frequency Analysis Of Trees Based On Kinect, He Peng, Shaojun Hu, Dongjian He

Journal of System Simulation

Abstract: The morphology and structure of plants were complex. It is of great significance to investigate the inherent motion law of plants under the action of external force, such as realistic animation formation, plant pruning, vibration picking and forest protection. A low cost outdoor tree complex motion capture method was explored, and the relationship between the stem motion and the external force was analyzed. The Kinect was used to capture the branches motion; MeanShift algorithm was used for tracking branches markers and the three-dimensional trajectory of the trunk was extracted according to the principle of Kinect coordinate transformation. A method …

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Multiple Faults Identification Of Three-Level Inverter, Yanxia Shen, Wu Juan, Zhipu Zhao, Zhicheng Ji Jun 2020

Multiple Faults Identification Of Three-Level Inverter, Yanxia Shen, Wu Juan, Zhipu Zhao, Zhicheng Ji

Journal of System Simulation

Abstract: A three-level neutral point clamped (NPC) inverter was taken as an example, phase current and bridge voltage in the fault states of single switch open and several switches open at the same time were analyzed, and a method based on reconstructive phase space (RPS) and wavelet packet analysis was proposed to identify three-level inverter faults. Based on RPS method, totally different reconstructed current trajectories were obtained, which showed the features of the inverter under different fault conditions. With the help of image processing technology, all kinds of faults with different phase currents were identified. The wavelet packet analysis was …

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Study Of Model Predictive Control Of Pwm Voltage Source Converterwithout Ac Electromotive Force Sensor, Li Hui, Li Zhi, Zhang Jin, Hanmei Peng Jun 2020

Study Of Model Predictive Control Of Pwm Voltage Source Converterwithout Ac Electromotive Force Sensor, Li Hui, Li Zhi, Zhang Jin, Hanmei Peng

Journal of System Simulation

Abstract: The traditional model-predictive-control (MPC), applied to three-phase converter, requires to use AC electromotive force sensor, and then it reduces the system reliability. A three-phase converter model predictive control without AC electromotive force sensor was proposed, and the virtual flux observer was constructed by DC bus voltage, switching signal and AC current. On this basis, a mathematical model of three-phase converter model predictive control quadratic programming (QP-MPC) based on virtual flux oriented was established. Using quadratic programming algorithm, the system can quickly calculate the optimal change, minimize the objective function, and obtain the optimal switch control signal, so as to …

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Under-Determined Blind Source Separation Anti-Collision Algorithm For Rfid Based On Hamming Weight Grouping, Yungang Jin, Xiaohong Zhang, Qiuli Wang Jun 2020

Under-Determined Blind Source Separation Anti-Collision Algorithm For Rfid Based On Hamming Weight Grouping, Yungang Jin, Xiaohong Zhang, Qiuli Wang

Journal of System Simulation

Abstract: The results of the algorithm ofunder-determined blind source separation RFID (Radio Frequency IDentification) system become worse or even lead to the degradation of overall system performancewith the large increase in the number of tags. Anovel parallelizable identification anti-collision algorithm based on constrained non negative matrix factorization (NMF) and Hamming weight grouping technology was proposed. The tag groupings were made by calculating the Hamming weight of the tag's front M bits, which were within the reader identification range. Each group was identified by the RFID reader according to the grouping sequence. Simulation results show that when the antenna number is …

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Fluid Flow, Heat And Mass Transfer In Hot Dip Galvanizing Bath, Shouqun Sun, Zhongshuang Wei, Huayang Lu Jun 2020

Fluid Flow, Heat And Mass Transfer In Hot Dip Galvanizing Bath, Shouqun Sun, Zhongshuang Wei, Huayang Lu

Journal of System Simulation

Abstract: Zinc dross is produced inevitably as a metallurgical phenomenon of continuous hot galvanizing process, and the quality of galvanizing is affected. The phenomenon is closely related to the physical field of molten zinc and more surface defects are easily produced if the zinc dross removal process is improperly handled. By constructing a three-dimensional viscous standard k-ε two equation turbulence model, the fluid flow, heat and mass transfer law and the distribution regularities of flow vortex were obtained under the specific initial conditions and boundary conditions. The simulation results of the observation points are basically in agreement with the experimental …

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Rtds Simulation Of Quasi-Proportional Resonant Control Of Statcom Under High Voltage, Zhang Yang, Xiaopin Yang Jun 2020

Rtds Simulation Of Quasi-Proportional Resonant Control Of Statcom Under High Voltage, Zhang Yang, Xiaopin Yang

Journal of System Simulation

Abstract: ±100 MVar high voltage static synchronous compensator (STATCOM) device is used for high voltage DC transmission which needs higher reliability. Faster response for its control system to deal with metal ground fault and other situations is required. Direct Current Control (DCC) can be used for these situations. Quasi- Proportional Resonant (quasi-PR) controller under DCC was studied and its parameters settings were discussed. The calculation methods of key parameters such as Kp and Kr were explained by mathematical deduction process. The STATCOM under higher voltage in Yunnan-Guangxi Funing transaction station was taken as an example for the calculation …

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Short-Term Prediction Of Wind Speed For Wind Farm Based On Ide-Lssvm Model, Zhang Yan, Dongfeng Wang, Han Pu Jun 2020

Short-Term Prediction Of Wind Speed For Wind Farm Based On Ide-Lssvm Model, Zhang Yan, Dongfeng Wang, Han Pu

Journal of System Simulation

Abstract: To improve the prediction accuracy of short-term wind speed for wind farm, an improved differential evolution algorithm was applied to optimize the parameters of least squares support vector machine. Two mutation operators were integrated, and the scale factor and crossover probability factor were changed gradually to adapt to the evolutionary generations. The good global search ability and population diversity in early stage of evolution were ensured, therefore the local search accuracy and the convergence speed in the late stage were enhanced. The forecasting performance of the least squares support vector machine optimized by IDE was improved. Simulation experiments on …

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Simulation Of Adaptive Dangerous Weather Warning Method Based On Airborne Weather Radar, Wang Lei, Xingang Liu, Wei Ming Jun 2020

Simulation Of Adaptive Dangerous Weather Warning Method Based On Airborne Weather Radar, Wang Lei, Xingang Liu, Wei Ming

Journal of System Simulation

Abstract: A kind of suitable airborne weather radar algorithm for different seasons, latitude and longitude and underlying surface in China was proposed. A simulation model of airborne weather radar for detecting strong storm weather based on the ground-based weather radar data was established. The improved algorithm of region segmentation and TITAN were used to identify strong storms and their characteristic parameters. China was divided into 16 climate characteristic regions (including East China Sea and South China Sea) per the latitude and longitude. The threshold of strong hail storm radar echo characteristic parameters in these areas was obtained, and the dangerous …

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Meteorological Service Federate Design And Realization Based On Hla, Yintian Liu, Xiaodong Wang, Zaikui Wang Jun 2020

Meteorological Service Federate Design And Realization Based On Hla, Yintian Liu, Xiaodong Wang, Zaikui Wang

Journal of System Simulation

Abstract: To increase flight safety and flight experience under special weather phenomena, the diversity and typical cases of special weather conditions should be considered in flight simulation training, the dynamic and successive meteorological data should be studied, and the insufficient of meteorological services should be overcome by comparing with the traditional flight simulator. The meteorological service with the generation model of multiple size of template library for typical special weather, the dynamical deduction model of meteorological data, and the interpolation calculation model of meteorological grid-point data were proposed. The meteorological service federate based on High Level Architecture (HLA) was established. …

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Modeling And Simulation Of Power Communication Networking Based On Quality Of Service, Xueyi Zhang, Juhui Gu, Meiqin Zhou Jun 2020

Modeling And Simulation Of Power Communication Networking Based On Quality Of Service, Xueyi Zhang, Juhui Gu, Meiqin Zhou

Journal of System Simulation

Abstract: For the complex network topology and channel time-varying characteristics of power line carrier communication in low voltage distribution grid, there is a phenomenon of slow convergence and stagnation when solving the routing problem with traditional ant colony algorithm. The algorithm used is easy to fall into premature and local optimization. An automatic networking algorithm based on transmission delay and the load factor of the evaluation factors was proposed and a genetic algorithm was joined at a later stage. The optimal solution was obtained by using the improved crossover operators, and the convergence of optimal algorithm solution was accelerated by …

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Simulation On Global Demand Information Sharing Value In B2b Supply Chain, Dongbo Hu, Shen Yue, Rudan Heng, Binbin Zhang Jun 2020

Simulation On Global Demand Information Sharing Value In B2b Supply Chain, Dongbo Hu, Shen Yue, Rudan Heng, Binbin Zhang

Journal of System Simulation

Abstract: In B2B e-commerce environment, a multi-agent simulation model based on the supply chain with multi suppliers was established to study the incentive effects of the global demand information sharing on suppliers and the effects of different parameters on these incentive effects. The research results are as follows: Compared with the local demand information sharing, the global demand information sharing can bring significant incentive effect to the supplier. The global demand information sharing is more valuable with the number of selected suppliers getting closer to the number of alternative suppliers, and an optimal number of alternative suppliers do exist. Based …

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Reachable Set Modeling Approach For Autonomous Vehicle's Dynamic Conflict Control, Cao Kai, Xiufang Liu, Yang Xu, Shen Peng Jun 2020

Reachable Set Modeling Approach For Autonomous Vehicle's Dynamic Conflict Control, Cao Kai, Xiufang Liu, Yang Xu, Shen Peng

Journal of System Simulation

Abstract: Aiming at the problem of active safety control modeling for autonomous vehicles, a combined method using the formal modeling and the dynamic non-cooperative game theory was proposed for discussing a control strategy of trajectory tracking and collision avoidance under dynamic conflict condition between autonomous vehicles. And it was proposed to divide the system control into three modes: trajectory tracking, collision avoidance and switching between trajectory tracking and collision avoidance. Taking into account the complexity as a hybrid systems and the existence of the trajectory tracking error for autonomous vehicle, a modeling approach based on reachable set was proposed for …

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Improved Particle Swarm Optimization Based On Lévy Flights, Rongyu Li, Wang Ying Jun 2020

Improved Particle Swarm Optimization Based On Lévy Flights, Rongyu Li, Wang Ying

Journal of System Simulation

Abstract: The particle swarm optimization (PSO) has some demerits, such as relapsing into local extremum, slow convergence velocity and low convergence precision in the late evolutionary. The Lévy particle swarm optimization (Lévy PSO) was proposed. In the particle position updating formula, Lévy PSO eliminated the impact of speed on the convergence rate, and used Levy flight to change the direction of particle positions movement to prevent particles getting into local optimum value, and then using greedy strategy to update the evaluation and choose the best solution to obtain the global optimum. The experimental results show that Lévy PSO can effectively …

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Performance Modeling Of Cryptographic Service System Virtualization Based On Issm, Songhui Guo, Qingbao Li, Sun Lei, Xuerong Gong, Tianchi Yang Jun 2020

Performance Modeling Of Cryptographic Service System Virtualization Based On Issm, Songhui Guo, Qingbao Li, Sun Lei, Xuerong Gong, Tianchi Yang

Journal of System Simulation

Abstract: The complicated architecture of cryptographic service system virtualization raised the difficulty of performance modeling. A performance modeling approach based on ISSMs was proposed. The approach divided the execution process into two stages, host preprocessing and arithmetic-module calculating, and built two sub-models based on queuing theory. On this basis, the effectiveness of this approach was verified. The results show that this method can analyze the impacts on system performance caused by task arrival rates, host and cryptographic card configurations quantitatively, and also be helpful for providing reasonable solutions to deploy virtualized cryptographic service system on cloud computing platforms.

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Modeling And Analysis Of Trust Attack Based On Object-Oriented Petri Net, Guangqiu Huang, Bai Lu Jun 2020

Modeling And Analysis Of Trust Attack Based On Object-Oriented Petri Net, Guangqiu Huang, Bai Lu

Journal of System Simulation

Abstract: On the basis of trust attack graph, the object-oriented trust attack Petri net model was put forward, the dynamic model described the attack behaviors among components of trust entity object. By introducing the object Petri net, the trust attack relations between trust entity objects and components were shown in the Petri net, simulating the collaborative work between the components. According to the new trust relation reconstruction rules, a trust attack path inference algorithm was proposed to make the attacker knowing the changes of harmfulness when attacking the components, thus the attacker could decide the attack direction. The maximal …

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Simulation Of Three-Region Commutation Torque Ripple Reduction For Brushless Dc Motor, Junjie Zhu, Haoran Liu Jun 2020

Simulation Of Three-Region Commutation Torque Ripple Reduction For Brushless Dc Motor, Junjie Zhu, Haoran Liu

Journal of System Simulation

Abstract: Aiming at brushless DC motor torque ripple during commutation section, new three-step three phases PWM method was proposed based on voltage balance principle, improving existing two phase PWM suppression method and suitable for all speed section. In this new method, the principle of non-commutation phase voltage and the neutral point voltage variation was researched. Voltage difference was remained the same by three-step PWM control strategy before and after commutation in order to suppression current ripple. Comparing with existing current slope research method, this new method is with a series of advantages: simple parameters, computing, and sampling circuit design. …

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Study On Visual Function Of Human Computer Interaction In Parachuting Simulator, Han Liang, Gong Xuan, Jiangyun Wang, Yanghua Du Jun 2020

Study On Visual Function Of Human Computer Interaction In Parachuting Simulator, Han Liang, Gong Xuan, Jiangyun Wang, Yanghua Du

Journal of System Simulation

Abstract: The parachuting training system consists of software and hardware, to simulate the parachute training through head mounted display and operating equipment, combined with system modeling, kinematic computation, visual display and expert evaluation. Principle methods of head mounted display with human-computer interactive function and exploitation of Vega Prime inventive exploration on the information collection of viewpoint are conducted. It provides a real time training environment through the configuration of environmental effects, scene control, collision detection and driving information.

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