检索结果-内蒙古大学图书馆

2008 2nd International Symposium on systems and Control in Aerospace and Astronautics, ISSCAA 2008

作者： Xinxiu, Zhou Jiancheng, Fang Gang, Liu Tao, Li Hai Conference Publishing Novel Inertial Instrument and Navigation System Technology Key Laboratory of Fundamental Science for National Defense Beijing University of Aeronautics and Astronautics Beijing 100083 China

PID controller has the problems of inferior dynamic quality and bad anti-interference ability. However, Variable structure controller has the disadvantages of chattering and big steady-state error. A new controller combines variable structure and PID control method for brushless DC motor (BLDCM) of Magnetic Suspended Reaction Flywheel (MSRW) is designed. It is based on analyzing of the MSRW system and modeling on BLDCM. The variable structure controller and the PID controller are combined to make a quite high precision speed controller. The simulation results prove that the new controller has the advantages of chattering and steady-state error reduction, system dynamic response improvement, invariance to the disturbances compared with the variable structure controller and the PID controller. Furthermore, this new controller has the features of simplicity of design and implement, which will be important for realizing the high precision and high stability satellite attitude control.

关键词： Brushless DC motors

来源：评论

学校读者我要写书评

暂无评论

Study of DoD architecture simulation validation based on UML and extended colored Petri nets

Study of DoD architecture simulation validation based on UML...

引用

2008 IEEE International Conference on Networking, Sensing and Control, ICNSC

作者： Bai, Xiao-Li Luo, Xue-Shan Bai, Xiao-Hui Yi, Xian-Qing Chen, Hong-Hui Guo, De-Ke Key Laboratory of C4ISR Technology College of Information System and Management National University of Defense Technology Changsha Hunan 410073 China College of Information Science and Technology HEI Long-jiang University Haerbin Heilongjiang 150080 China

ISBN: (纸本)9781424416851

Department of Defence Architecture Framework(DoDAF) is an important method to ensure the quality of system design. One way for DoD architecture validation and assess is to transform the DoD architecture products into executable models, then the performance of DoD architecture can be tested through analyzing model execution process and result. Based on the different advantage of UML(Unified Modelling Language) and Petri nets, the paper applies some kinds of views in UML to describe the relative DoD architecture products. Considering the relationship among the products, the UML views for products are transformed into ECPN (Extended Colored Petri Nets) simulation models according to the transformation rules. So the dynamic behavior of system can be displayed by those simulation model, and whether the time-order relation, information flow and system interface is reasonable, or the system function satisfies the military requirement, and the change of system state is correct, can be checked evidently. At last, the paper gives a case in the air defense system using simulation validation method proposed by it.

关键词： Unified Modeling Language

来源：评论

学校读者我要写书评

暂无评论

Data segments aggregation performance in next generation avionics systems

引用

Guangxue Xuebao/Acta Optica Sinica 2008年第SUPPL. 2期28卷 253-257页

作者： Huang, Hui He, Hao Jin, Yaohui Huang, Haoyi Wu, Jianmin State Key Laboratory on Advanced Communication Systems and Networks Shanghai Jiaotong University Shanghai 200240 China National Defense Science and Technology Key Laboratory for Avionics System Integration Technology Shanghai 200233 China

We integrate the advantages of optical packet switching (OPS) network and fibre channel (FC) technology, and put forward fibre channel transportation based on optical packet switching network (FC over OPS) as a solution for next generation avionics systems internetworking. We focus our research work on the interrelation between data segments aggregation and network real-timing performance. By simulation, we analyze the impact that bandwidth, minimum efficiency threshold and timing contribute to the network real-timing. Furthermore, we complete hardware prototype design and simulation, compare the results between software and hardware simulation and analyze the performance of this algorithm.

关键词： Packet switching

来源：评论

学校读者我要写书评

暂无评论

Synchronization-based Overlay Construction for Resilient P2P Streaming

Synchronization-based Overlay Construction for Resilient P2P...

引用

7th World Congress on Intelligent Control and Automation (WCICA 2008), vol.20

作者： Rongtao Liao Shengsheng Yu Jing Yu School of Computer Science and Technology Huazhong University of Science and Technology Wuhan China China Ship Development and Design Center National Key Laboratory of EMC Wuhan China

Previous works in P2P streaming provide many kinds of solutions to construct an effective streaming overlay, they either lack of flexibility or can not gain global optimal performance. A new synchronization based approach proposed in this paper use a fully distributed scheme to achieve optimal peer selection and dynamic peer management. Especially, the working set discrepancy between peers is taken into account for overlay construction to increase the continuity of playback during streaming session. The synchronization estimation based membership management scheme, which is the key technique adopted by this paper, correlates the peer selection to network performance and data synchronization between peers. A distributed dynamic peer suggestion scheme is also proposed;it is resilient to network dynamic and can potentially help the system to converge to a reasonable performance. With respect to data transmission, this system adopts a resilient data management and transmission method striving to eliminate the influence of packet loss. The simulations of prototype over random network demonstrate the feasibility and effectiveness of this solution.

关键词： P2P Live Streaming Synchronization Estimation Membership Management Data Transmission

来源：评论

学校读者我要写书评

暂无评论

Simulation design of Geomagnetic Aided Inertial Navigation system

Simulation design of Geomagnetic Aided Inertial Navigation S...

引用

International Symposium on systems and Control in Aerospace and Astronautics (ISSCAA)

作者： Haonan Feng Zhaohua Yang Jiancheng Fang Key laboratory of Fundamental Science National Defense of Novel Inertial Instrument and Navigation System Technology BUAA Beijing China

Geomagnetic aided inertial navigation system (GAINS) is an important manner of the future passive navigation. The theory and composition of GAINS are addressed and key technologies of GAINS, including the selection of matching region, matching algorithm comparison and information fusion are analyzed. Simulation platform of geomagnetic aided inertial navigation system is established and analyzed through simulation. The results show that geomagnetic matching algorithm based on ICCP algorithm has better location accuracy than traditional contour matching method. The architecture of the simulation platform is reasonable and reliable.

关键词： Geomagnetism Inertial navigation Magnetic separation Vehicles Magnetometers Radio navigation Magnetic analysis Analytical models Real time systems Regulators

来源：评论

学校读者我要写书评

暂无评论

Flight-by-wire control strategy: An implementation of stepping simulation approach

Flight-by-wire control strategy: An implementation of steppi...

引用

International Symposium on systems and Control in Aerospace and Astronautics (ISSCAA)

作者： F. Xu T. Wang Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Nanjing China

Flight control system is extremely important for the aircraft flight safety and quality. With the rapid and continual development in modern aeronautical fields, fly-by-wire control (FBW)system has become the leading of aircraft design and application. In this paper, aim at the need of the certain cargo-transport, the modeling and simulation as well as the parametric-optimization of flight control system are systematically discussed, based on MATLAB/Simulink. The mechanical model of the flight control system is presented, and a suit of flight control law is proposed. The model of flight control system is set forth in MATLAB/Simulink based on the control law, the real-time simulation of control system, the analysis of planepsilas dynamic response characteristics, and the modification and optimization of the system parameters are implemented. The FBW system is analyzed by stepping simulation, and the effects on the dynamic character of the whole systempsilas response due to each block is studied.

关键词： Aerospace simulation Aerospace control Mathematical model Aircraft MATLAB Analytical models Aerodynamics Air safety Aerospace safety Real time systems

来源：评论

学校读者我要写书评

暂无评论

Analysis on the parameters of adhesively bonding patch repairing cracked sandwich face panel

Analysis on the parameters of adhesively bonding patch repai...

引用

International Conference on system Simulation and Scientific Computing, ICSC

作者： Yuequan Wang Mingbo Tong Shuhua Zhu Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Nanjing China

The parameters of adhesively bonding patch, which include patch materials, patch size, patch thickness, have been analyzed on the stress concentration factor and the stress intensity factor (SIF) thanks to the 3D finite element method (FEM) in the paper. The adhesive shear modulus and thickness are studied in this paper as well. The aluminum sandwich face panel is analyzed and the results show that the Boron/Epoxy composite patch reduces more stress concentration factor and SIF comparing with the other patches. The stress concentration factor reaches the minimum when the fiber orientates the tension direction. Meanwhile, the stress concentration in the patch and the adhesive reach the maximum. The stress concentration factor in the aluminum face sheet decreases with the increasing patch thickness. But the effect of the patch thickness weakens when the patch thickness is larger than the face panel. The impact of the adhesive thickness on the stress concentration of the face panel reduces with the increasing adhesive shear modulus. The stress concentration factor increases when the adhesive thickness increases. The results are useful to design the bonded composite patch repair.

关键词： Bonding Stress Aluminum Laboratories Space technology Vehicles Laminates Finite element methods Aircraft Resists

来源：评论

学校读者我要写书评

暂无评论

design of an adaptive shock absorber of landing gear and preliminary analysis on taxiing performance

Design of an adaptive shock absorber of landing gear and pre...

引用

International Conference on system Simulation and Scientific Computing, ICSC

作者： Shuhua Zhu Mingbo Tong Jie Xu Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Nanjing China Structure department ChengDu Aircraft Design and Research Institute Chengdu China

A special adaptive shock strut of landing gear with double-cavity and double damping is studied in the paper. Its mathematical model and virtual prototype, which is established based on the software ADAMS, are described. The paper has emphatically studied the sensitivities of its different configurations and main parameters to the taxiing performance of landing gear. The analysis shows that all of the side orifice, variable orifice and the high pressure cavity can reduce the overload and stroke of the adaptive shock absorber. The results also show that adjusting the pressure of the double cavities can reduce more overload than adjusting these volumes. The results obtained in the paper have reference value for the landing gear design of the large aircraft.

关键词： Shock absorbers Gears Performance analysis Orifices Electric shock Damping Mathematical model Software prototyping Virtual prototyping Aircraft

来源：评论

学校读者我要写书评

暂无评论

An Automatic and Scalable Testing Tool for Workflow systems

An Automatic and Scalable Testing Tool for Workflow Systems

引用

International Conference on Grid and Pervasive Computing Workshops, GPC

作者： Lin Quan Xiaozhu Lin Jianmin Wang Key Laboratory for Information System Security Ministry of Education China School of Software Tsinghua University Beijing China Computer and Information Management Center Tsinghua University China Tsinghua National Laboratory for Information Science and Technology China

Nowadays workflow systems are widely deployed around the world, especially within large international corporations. Thus the performance evaluation of these workflow systems becomes an important topic, especially in grid environment. We have developed an automatic and scalable testing tool to evaluate workflow systems. This tool is named Scalable Workflow system Evaluation Tool (SWEET). SWEET can automatically test against workflow systems according to a highly customizable process template specified by users. It can also provide multi-layer performance metrics related to response time, throughput and fairness. Further, it can adoptively determine the maximum concurrency of a workflow system under a desired average processing time, using control theory (PI Controller). In this paper, we will present the design and architecture of SWEET. We will also discuss the evaluation metrics and our implementation of such a framework. Finally, we will give detailed experimental results and analysis.

关键词： Automatic testing system testing Delay Concurrent computing Measurement Pervasive computing Software testing Software tools Laboratories Automatic control

来源：评论

学校读者我要写书评

暂无评论

Modified min-sum decoding algorithm for LDPC codes based on classified correction

Modified min-sum decoding algorithm for LDPC codes based on ...

引用

International Conference on Communications and Networking in china (chinaCOM)

作者： Zhou Zhong Yunzhou Li Xiang Chen Hanying Hu Jing Wang State Key Laboratory on Microwave and Digital Communications National Laboratory for Information Science and Technology Department of Electronic Engineering Tsinghua University Beijing China National Digital Switching System Engineering and Technological Research and Development Center Zhengzhou China

In this paper, a modified min-sum decoding algorithm based on classified correction is proposed for low density parity check (LDPC) codes. Different from the single correction in the normalized belief propagation (BP)-based and offset BP-based algorithms [4], the proposed algorithm utilizes two corrections for both minimum and sub-minimum magnitudes of input messages in check nodes. These two correction factors can be obtained by analyzing the offset of updated messages in check nodes between the BP and the min-sum algorithms associated with check node degree. Simulation results show that the proposed algorithm can achieve performance very close to that of the BP algorithm. Furthermore, the FPGA implementation of this algorithm can reach a throughput of 200 Mbps at BER=10 -6 with lower complexity and fewer resources than the BP algorithm.

关键词： Parity check codes Iterative algorithms Approximation algorithms Iterative decoding AWGN Laboratories Microwave technology Belief propagation Algorithm design and analysis Field programmable gate arrays

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：