e-Science 环境下复合数字对象研究   总被引：2，自引：0，他引：2  

陈仕吉  史丽文  左文革 《现代图书情报技术》2009,3(2):33-38

e-Science,即“数字科研”,是建立在网格技术基础之上的一种全新的科学研究环境。分析e-Science环境下数据资源的新变化,并简要介绍e-Science环境下的封装科学数据、计算资源、工作流和起源元数据等各种数据资源的复合数字对象研究进展。  相似文献   

Robust orbital transfer for low earth orbit spacecraft with small-thrust     

Xuebo Yang  Peng Shi 《Journal of The Franklin Institute》2010,347(10):1863-1887

This paper studies the problem of robust orbital control for low earth orbit (LEO) spacecraft rendezvous subjects to the parameter uncertainties, the constraints of small-thrust and guaranteed cost during the orbital transfer process. In particular, the rendezvous process is divided into in-plane motion and out-plane motion based on C-W equations, and the relative motion models with parameter uncertainties are established. By considering the property of null controllable with vanishing energy (NCVE), the problem of orbital transfer control with small thrust and bounded control cost is proposed. A new Lyapunov approach is introduced, and the controller design problem is cast into a convex optimization problem subjects to linear matrix inequality (LMI) constraints. With the obtained controller, the orbit transfer process can be accomplished with small thrust and the control cost has an upper bound simultaneously. Different possible initial states of the transfer orbit are also analyzed for the controller design. An illustrative example is provided to show the effectiveness of the proposed control design method, and the different performances caused by different initial states of the transfer orbit are illustrated.  相似文献   

Observer-based sliding mode control for a class of discrete systems via delta operator approach     

Hongjiu Yang  Peng Shi 《Journal of The Franklin Institute》2010,347(7):1199-1688

In this paper, an observer-based sliding mode control (SMC) problem is investigated for a class of uncertain delta operator systems with nonlinear exogenous disturbance. A novel robust stability condition is obtained for a sliding mode dynamics by using Lyapunov theory in delta domain. Based on a designed sliding mode observer, a sliding mode controller is synthesized by employing SMC theory combined with reaching law technique. The robust asymptotical stability problem is also discussed for the closed-loop system composed of the observer dynamics and the state estimation error dynamics. Furthermore, the reachability of sliding surfaces is also investigated in state-estimate space and estimation error space, respectively. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the developed method.  相似文献   

H_∞ filtering for nonlinear systems via neural networks     

Xiaoli Luan  Peng Shi 《Journal of The Franklin Institute》2010,347(6):1035-1046

A novel H_∞ filter design methodology has been presented for a general class of nonlinear systems. Different from existing nonlinear filtering design, the nonlinearities are approximated using neural networks, and then are modeled based on linear difference inclusions, which makes the structure of the desired filter simpler and parameter turning easier and has the advantages of guaranteed stability, numeral robustness, bounded estimation accuracy. A unified framework is established to solve the addressed H_∞ filtering problem by exploiting linear matrix inequality (LMI) approach. A numerical example shows that the filtering error systems will work well against bounded error between a nonlinear dynamical system and a multilayer neural network.  相似文献   

民主精神与科学创新——纪念竺可桢诞辰120周年          下载免费PDF全文

施雅风 《中国科学院院刊》2010,25(4):454-460

竺可桢院士是我国近现代最卓越、影响最深远的大科学家、大教育家之一。2010年3月7日是竺先生诞辰120周年,在改革开放的今天纪念竺可桢先生具有特殊的意义。竺先生自1921年在南京前东南大学创  相似文献   

公共危机事件网络舆情应对机制及策略研究   总被引：3，自引：0，他引：3  

史波 《情报理论与实践》2010,33(7)

公共危机事件网络舆情研究是公共危机管理研究中一个新的和重要的组成部分.在对网络舆情演变机理进行归纳总结的基础上,分析了应对机制与演变机理之间的内在关系,并提出了"四位一体"的应对机制体系框架.从管理运行机制、预警机制、处置机制和善后机制4个方面,系统地提出了公共危机事件网络舆情的应对策略.  相似文献   

繁荣基础研究 引领城市创新     

沈文庆 《中国科学基金》2010,(5)

<正>非常高兴有这样的机会参加今天的论坛。值此中国2010年上海世界博览会隆重举行之际,我们在这里举办"科技创新与城市未来"主题论坛。"千里逢迎,高朋满座",来自海内外的朋友济济一堂,共同交流城市创新发展愿景,对筹划城市未来意义深远。在这里,我谈几点看法,与各位同仁交流。  相似文献   

男性生殖生理学研究进展——本课题组研究成果回眸     

石其贤  陈文颖  袁玉英  倪崖  李坤  陈璋辉  钟翠玲  桑国卫 《中国科学基金》2010,(5)

本文阐述了本课题组在国家自然科学基金和美国洛氏基金会及国家"973"计划等基金资助下,在男性生殖生理学基础研究方面,特别是围绕受精生物学方面取得的一些重要进展。对此期间获得的主要研究成果,从内容及其意义、基金资助、获奖情况等几个方面分别进行综述。  相似文献   

取消左转可缓解交通拥堵的计算机仿真     

石文堂  曾沥锋  汪祖民 《中国科技信息》2010,(3):256-257,262

围绕三排道十字信号交叉口取消左转弯的管理措施,建立了计算机仿真模型。结合概率论与数理统计方法对车辆生成模型进行泊松分布假设检验,选取通行能力作为判定指标,实现了禁左前后通行能力的对比．  相似文献   

在线行走式板型仪的实际应用     

段友超  史静娴 《中国科技信息》2010,(6):106-107

本文介绍了河北钢铁集团唐钢热轧1700mm生产线的在线行走式板型仪的测试原理、设备构成、主要技术性能、应用范围.整套系统结构简单,成本低廉,抗干扰性好,调试方便.  相似文献