以某配装2台某型涡扇发动机的民用飞机为例,通过该飞机对左发全权限数字电子控制系统(FADEC)进行升级抑制自动起飞推力管理系统(即Automatic Takeoff Thrust Control System,简写为ATTCS)自动触发功能后进行检飞,检查ATTCS以及空调系统...以某配装2台某型涡扇发动机的民用飞机为例,通过该飞机对左发全权限数字电子控制系统(FADEC)进行升级抑制自动起飞推力管理系统(即Automatic Takeoff Thrust Control System,简写为ATTCS)自动触发功能后进行检飞,检查ATTCS以及空调系统和防冰系统的工作逻辑。通过对检飞数据的分析以及对ATTCS触发逻辑的梳理,对检飞内容和方法提出一些建议。对于同样具有ATTCS系统的飞机的试飞有一定的参考意义。展开更多
Internet traffic classification plays an important role in network management, and many approaches have been proposed to classify different kinds of internet traffics. A novel approach was proposed to classify network...Internet traffic classification plays an important role in network management, and many approaches have been proposed to classify different kinds of internet traffics. A novel approach was proposed to classify network applications by optimized back-propagation (BP) neural network. Particle swarm optimization (PSO) algorithm was used to optimize the BP neural network. And in order to increase the identification performance, wavelet packet decomposition (WPD) was used to extract several hidden features from the time-frequency information of network traffic. The experimental results show that the average classification accuracy of various network applications can reach 97%. Moreover, this approach optimized by BP neural network takes 50% of the training time compared with the traditional neural network.展开更多
Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimeusioual prefix packet classification (PPC) is the popular one. This paper analyz...Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimeusioual prefix packet classification (PPC) is the popular one. This paper analyzes the problem of ruler conflict, and then presents a TCAM-based two-dimensional PPC algorithm. This algorithm makes use of the parallelism of TCAM to lookup the longest prefix in one instruction cycle. Then it uses a memory image and associated data structures to eliminate the conflicts between rulers, and performs a fast two-dimeusional PPC. Compared with other algorithms, this algorithm has the least time complexity and less space complexity.展开更多
The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The ...The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The influences of gas phase orifice F-factor and clear liquid height Hc on the amount of liquid lifted, Q, were examined. The corresponding correlation between Q with F-factor and equivalent diameter of perforated holes as well as Hc was obtained. Furthermore, the non-steady state mass transfer performance of JCPT was tested by the humidification of air with water. Finally, by the analysis of data and comparison, it was found that the JCPT tray with single cap and two holes exhibited the highest mass transfer efficiency and best performance.展开更多
Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lea...Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lead to large simulation times, often exceeding transient real time. Artificial neural networks （ANNs） may be advantageous in this context, the main advantage being the speed of computation, the capability of generalizing from the few examples, robustness to noisy and partially incomplete data and the capability of performing empirical input-output mapping without complete knowledge of underlying physics. In this paper, the simulation of steam generator is considered as an example to show the potentialities of this tool. The data required for training and testing the ANN is taken from the steam generator at Abott Power Plant, Champaign （USA）. The total number of samples is 9600 which are taken at a sampling time of three seconds. The performance of boiler （drum pressure, steam flow rate） has been verified and tested using ANN, under the changes in fuel flow rate, air flow rate and load disturbance. Using ANN, input-output mapping is done and it is observed that ANN allows a good reproduction of non-linear behaviors of inputs and outputs.展开更多
文摘以某配装2台某型涡扇发动机的民用飞机为例,通过该飞机对左发全权限数字电子控制系统(FADEC)进行升级抑制自动起飞推力管理系统(即Automatic Takeoff Thrust Control System,简写为ATTCS)自动触发功能后进行检飞,检查ATTCS以及空调系统和防冰系统的工作逻辑。通过对检飞数据的分析以及对ATTCS触发逻辑的梳理,对检飞内容和方法提出一些建议。对于同样具有ATTCS系统的飞机的试飞有一定的参考意义。
基金Project(2007CB311106) supported by National Key Basic Research Program of ChinaProject(NEUL20090101) supported by the Foundation of National Information Control Laboratory of China
文摘Internet traffic classification plays an important role in network management, and many approaches have been proposed to classify different kinds of internet traffics. A novel approach was proposed to classify network applications by optimized back-propagation (BP) neural network. Particle swarm optimization (PSO) algorithm was used to optimize the BP neural network. And in order to increase the identification performance, wavelet packet decomposition (WPD) was used to extract several hidden features from the time-frequency information of network traffic. The experimental results show that the average classification accuracy of various network applications can reach 97%. Moreover, this approach optimized by BP neural network takes 50% of the training time compared with the traditional neural network.
基金Foundation item: supported by Intel Corporation (No. 9078)
文摘Packet classification (PC) has become the main method to support the quality of service and security of network application. And two-dimeusioual prefix packet classification (PPC) is the popular one. This paper analyzes the problem of ruler conflict, and then presents a TCAM-based two-dimensional PPC algorithm. This algorithm makes use of the parallelism of TCAM to lookup the longest prefix in one instruction cycle. Then it uses a memory image and associated data structures to eliminate the conflicts between rulers, and performs a fast two-dimeusional PPC. Compared with other algorithms, this algorithm has the least time complexity and less space complexity.
文摘The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The influences of gas phase orifice F-factor and clear liquid height Hc on the amount of liquid lifted, Q, were examined. The corresponding correlation between Q with F-factor and equivalent diameter of perforated holes as well as Hc was obtained. Furthermore, the non-steady state mass transfer performance of JCPT was tested by the humidification of air with water. Finally, by the analysis of data and comparison, it was found that the JCPT tray with single cap and two holes exhibited the highest mass transfer efficiency and best performance.
文摘Numerical simulation of complex systems and components by computers is a fundamental phase of any modern engineering activity. The traditional methods of simulation typically entail long, iterative processes which lead to large simulation times, often exceeding transient real time. Artificial neural networks （ANNs） may be advantageous in this context, the main advantage being the speed of computation, the capability of generalizing from the few examples, robustness to noisy and partially incomplete data and the capability of performing empirical input-output mapping without complete knowledge of underlying physics. In this paper, the simulation of steam generator is considered as an example to show the potentialities of this tool. The data required for training and testing the ANN is taken from the steam generator at Abott Power Plant, Champaign （USA）. The total number of samples is 9600 which are taken at a sampling time of three seconds. The performance of boiler （drum pressure, steam flow rate） has been verified and tested using ANN, under the changes in fuel flow rate, air flow rate and load disturbance. Using ANN, input-output mapping is done and it is observed that ANN allows a good reproduction of non-linear behaviors of inputs and outputs.
