IN S/G PS组合导航具有精度高、抗干扰性好等优点,在各个领域得到广泛应用。惯导姿态仿真是组合导航的关键环节,针对组合导航的惯导姿态仿真问题,提出一种利用STK软件进行场景建模,根据姿态场景数据控制三轴转台,实现惯导姿态的半实物...IN S/G PS组合导航具有精度高、抗干扰性好等优点,在各个领域得到广泛应用。惯导姿态仿真是组合导航的关键环节,针对组合导航的惯导姿态仿真问题,提出一种利用STK软件进行场景建模,根据姿态场景数据控制三轴转台,实现惯导姿态的半实物仿真。实验结果表明,该半实物仿真系统设计合理,基于STK的场景建模具有通用性和可扩展性,转台控制降低了姿态仿真的误差,为组合导航姿态测试提供了良好的平台,具有一定的推广使用价值。展开更多
This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra...This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra-measures for the snow issue proposed in the past decades are provided by reviewing previous studies. Next, the methodology for investigating the snow issue developed by High-Speed Train Research Center of Central South University is introduced, including the numerical simulation research platform and the experimental devices for two-phase flow wind tunnel tests. Then, effective anti-snow flow control schemes for guiding the underbody airflow and their impact on the motion and accretion of snow in the installation region of the bogies are presented. Finally, the remaining investigating challenge for the snow issue of HST and the future research with respect to the challenge are provided from an engineering application viewpoint.展开更多
Security problem is an important issue for Wireless Sensor Network.The paper focuses on the privacy protection of WSN applications.An anonymity enhancement tactic based on pseudonym mechanism is presented for clustere...Security problem is an important issue for Wireless Sensor Network.The paper focuses on the privacy protection of WSN applications.An anonymity enhancement tactic based on pseudonym mechanism is presented for clustered Wireless Sensor Network,which provides anonymity for both the sensors within a cluster and the cluster head nodes.Simulation experiments are launched through NS2 platform to validate the anonymity performance.The theoretical analysis and empirical study imply that the proposed scheme based on pseudonym can protect the privacies of both the sensor nodes and the cluster head nodes.The work is valuable and the experimental results are convincible.展开更多
In the evaluation of the necessary measurement of aeronautical means to face to a certain military operative problem, the development of an appropriate tool is of importance. Conventional techniques are considered ina...In the evaluation of the necessary measurement of aeronautical means to face to a certain military operative problem, the development of an appropriate tool is of importance. Conventional techniques are considered inadequate in the analysis of military operative problems in presence of a self-attrition behavior from one of the involved parts. In this paper a traditional algorithm for measuring military power is implemented and analyzed and then we improve this traditional algorithm on the basis of the kind of degradation that systematically takes place in self-destructive systems. In terms of traditional analysis, the evolution of a war is essentially an unreal sequence of repetitive cycles. So a time-dependent function was introduced in improved the algorithm. The development of this tool of prediction has the aim to argue the management of taking decisions in this type of crisis and complements itself with historical arguments or references of rigor. A computer software show results that allows to estimate the costs of the support and to visualize the graphs associated with the degradation of the system and his temporary evolution. The improved algorithm is more suitable than the traditional one in software simulations.展开更多
The fault accommodation problem for time-delay system is studied in this paper. The progressive accommodation strategy based on the Newton-Raphson scheme is proposed to solve this problem. This accommodation scheme ca...The fault accommodation problem for time-delay system is studied in this paper. The progressive accommodation strategy based on the Newton-Raphson scheme is proposed to solve this problem. This accommodation scheme can significantly reduces the loss of performance and risk associated with system instability which results from the time-delay needed by fault accommodation algorithms to provide a solution. Simulation results are given to illustrate the efficiency of the provided method.展开更多
This paper introduces the basic viewpoints and characteristics of Bayesian statistics. Which provides a theoretical basis for solving the problem of small sample of flight simulator using Bayesian method. A series of ...This paper introduces the basic viewpoints and characteristics of Bayesian statistics. Which provides a theoretical basis for solving the problem of small sample of flight simulator using Bayesian method. A series of formulas were derived to establish the Bayesian reliability modeling and evaluation model for flight simulation equipment. The two key problems of Bayesian method were pointed out as follows： obtaining the prior distribution of WeibuU parameter, calculating the parameter a posterior distribution and parameter estimation without analytic solution, and proposing the corresponding solution scheme.展开更多
Nowadays the actual parking situation is becoming more and more complex. Because of the inexpert driving skill of novice drivers, there is often collision in the parking process. Fortunately, with the development of p...Nowadays the actual parking situation is becoming more and more complex. Because of the inexpert driving skill of novice drivers, there is often collision in the parking process. Fortunately, with the development of path planning and intelligent control technology, the appearance of the automatic parking control system will provide a good solution to the narrow parking problems. Here with the help of MATLAB/Simulink, we build a simulation platform, and then respectively simulate the parallel parking and vertical parking process, to seek for the best initial parking point and path.展开更多
Greater complexity and interconnectivity across systems embracing electrical power technologies has meant that cyber-security issues have attracted significant attention. In this paper a simulation environment for int...Greater complexity and interconnectivity across systems embracing electrical power technologies has meant that cyber-security issues have attracted significant attention. In this paper a simulation environment for intrusion detection system in IEC 61850 standard-based substation automation system is provided to test simulated attacks on IEDs （intelligent electronic devices）. Intrusion detection is the process of detecting malicious attacker, so it is an effective and mature security mechanism to protect electrical facility. However, it is not harnessed when securing IEC 61850 automated substation. To prove the detection capability of the system testing environment was developed to analyze and test attacks simulated with different test cases. It shows that the simulation environment works accordingly to various network traffic scenarios and eventually proves the functionality of intrusion detection system to be later deployed in the real IEC 61850 based substation automation system site.展开更多
Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure mo...Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.展开更多
Rapid path planner plays an important role in autonomous ground vehicle （AGV） operation. Depending on the non-holonomic kinematics constraints of AGV, its path planning problem is discussed. Since rapidly-exploring ...Rapid path planner plays an important role in autonomous ground vehicle （AGV） operation. Depending on the non-holonomic kinematics constraints of AGV, its path planning problem is discussed. Since rapidly-exploring random tree （RRT） can directly take non-holonomic constraints into consideration, it is selected to solve this problem. By applying extra constraints on the movement, the generation of new configuration in RRT algorithm is simplified and accelerated. With section collision detection method applied, collision detection within the planer becomes more accurate and efficient. Then a new path planner is developed. This method complies with the non-holonomic constraints, avoids obstacles effectively and can be rapidly carried out while the vehicle is running. Simulation shows that this path planner can complete path planning in less than 0.5 s for a 170 mx 170 m area with moderate obstacle complexity.展开更多
基金Project(2016YFB1200404)supported by the National Key Research and Development Program of ChinaProjects(51605044,U1534210)supported by the National Science Foundation of China。
文摘This paper reviews the current status of investigation on snow accumulation on the bogies of high-speed trains(HSTs) running in snowy region. First, the background of the snow issue occurring to the HST and the contra-measures for the snow issue proposed in the past decades are provided by reviewing previous studies. Next, the methodology for investigating the snow issue developed by High-Speed Train Research Center of Central South University is introduced, including the numerical simulation research platform and the experimental devices for two-phase flow wind tunnel tests. Then, effective anti-snow flow control schemes for guiding the underbody airflow and their impact on the motion and accretion of snow in the installation region of the bogies are presented. Finally, the remaining investigating challenge for the snow issue of HST and the future research with respect to the challenge are provided from an engineering application viewpoint.
基金the National Natural Science Foundation of China (NSFC) under grant No.61309024,the National Key Basic Research Program of China (973) under Grant No.2013CB834204,the Fundamental Research Funds for the Central Universities under grant No.14CX06009A at China University of Petroleum
文摘Security problem is an important issue for Wireless Sensor Network.The paper focuses on the privacy protection of WSN applications.An anonymity enhancement tactic based on pseudonym mechanism is presented for clustered Wireless Sensor Network,which provides anonymity for both the sensors within a cluster and the cluster head nodes.Simulation experiments are launched through NS2 platform to validate the anonymity performance.The theoretical analysis and empirical study imply that the proposed scheme based on pseudonym can protect the privacies of both the sensor nodes and the cluster head nodes.The work is valuable and the experimental results are convincible.
文摘In the evaluation of the necessary measurement of aeronautical means to face to a certain military operative problem, the development of an appropriate tool is of importance. Conventional techniques are considered inadequate in the analysis of military operative problems in presence of a self-attrition behavior from one of the involved parts. In this paper a traditional algorithm for measuring military power is implemented and analyzed and then we improve this traditional algorithm on the basis of the kind of degradation that systematically takes place in self-destructive systems. In terms of traditional analysis, the evolution of a war is essentially an unreal sequence of repetitive cycles. So a time-dependent function was introduced in improved the algorithm. The development of this tool of prediction has the aim to argue the management of taking decisions in this type of crisis and complements itself with historical arguments or references of rigor. A computer software show results that allows to estimate the costs of the support and to visualize the graphs associated with the degradation of the system and his temporary evolution. The improved algorithm is more suitable than the traditional one in software simulations.
基金National Natural Science Foundation of China (No.60574081)
文摘The fault accommodation problem for time-delay system is studied in this paper. The progressive accommodation strategy based on the Newton-Raphson scheme is proposed to solve this problem. This accommodation scheme can significantly reduces the loss of performance and risk associated with system instability which results from the time-delay needed by fault accommodation algorithms to provide a solution. Simulation results are given to illustrate the efficiency of the provided method.
文摘This paper introduces the basic viewpoints and characteristics of Bayesian statistics. Which provides a theoretical basis for solving the problem of small sample of flight simulator using Bayesian method. A series of formulas were derived to establish the Bayesian reliability modeling and evaluation model for flight simulation equipment. The two key problems of Bayesian method were pointed out as follows： obtaining the prior distribution of WeibuU parameter, calculating the parameter a posterior distribution and parameter estimation without analytic solution, and proposing the corresponding solution scheme.
文摘Nowadays the actual parking situation is becoming more and more complex. Because of the inexpert driving skill of novice drivers, there is often collision in the parking process. Fortunately, with the development of path planning and intelligent control technology, the appearance of the automatic parking control system will provide a good solution to the narrow parking problems. Here with the help of MATLAB/Simulink, we build a simulation platform, and then respectively simulate the parallel parking and vertical parking process, to seek for the best initial parking point and path.
文摘Greater complexity and interconnectivity across systems embracing electrical power technologies has meant that cyber-security issues have attracted significant attention. In this paper a simulation environment for intrusion detection system in IEC 61850 standard-based substation automation system is provided to test simulated attacks on IEDs （intelligent electronic devices）. Intrusion detection is the process of detecting malicious attacker, so it is an effective and mature security mechanism to protect electrical facility. However, it is not harnessed when securing IEC 61850 automated substation. To prove the detection capability of the system testing environment was developed to analyze and test attacks simulated with different test cases. It shows that the simulation environment works accordingly to various network traffic scenarios and eventually proves the functionality of intrusion detection system to be later deployed in the real IEC 61850 based substation automation system site.
基金Supported by the National Basic Research Program of China under Grant No. 2012CB725400the National Natural Science Foundation of China under Grant No. 71131001-1the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety under Grant No. RCS2011ZZ003, Beijing Jiaotong University
文摘Based on the Nagel-Schreckenberg model, we propose a new cellular automata model to simulate the urban rail traffic flow under moving block system and present a new minimum instantaneous distance formula under pure moving block. We also analyze the characteristics of the urban rail traffic flow under the influence of train density, station dwell times, the length of train, and the train velocity. Train delays can be decreased effectively through flexible departure intervals according to the preceding train type before its departure. The results demonstrate that a suitable adjustment of the current train velocity based on the following train velocity can greatly shorten the minimum departure intervals and then increase the capacity of rail transit.
文摘Rapid path planner plays an important role in autonomous ground vehicle （AGV） operation. Depending on the non-holonomic kinematics constraints of AGV, its path planning problem is discussed. Since rapidly-exploring random tree （RRT） can directly take non-holonomic constraints into consideration, it is selected to solve this problem. By applying extra constraints on the movement, the generation of new configuration in RRT algorithm is simplified and accelerated. With section collision detection method applied, collision detection within the planer becomes more accurate and efficient. Then a new path planner is developed. This method complies with the non-holonomic constraints, avoids obstacles effectively and can be rapidly carried out while the vehicle is running. Simulation shows that this path planner can complete path planning in less than 0.5 s for a 170 mx 170 m area with moderate obstacle complexity.
