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991.
This paper investigates the problem of adaptive stabilization by output feedback for a class of uncertain nonlinear systems. The distinguishing feature of such a class of systems is the presence of uncertain control coefficient and unmeasured states dependent growth with growth rate of polynomial‐of‐output multiplying an unknown constant. First, new high‐gain K‐filters with two dynamic gains are introduced, and an appropriate state observer is constructed based on the K‐filters. Then, motivated by the universal control idea, the backstepping scheme is successfully developed for the adaptive output feedback control design. By appropriate choice of the design parameters, the global stability of the closed‐loop system can be guaranteed. Finally, numerical simulations are provided to illustrate the correctness of the theoretical results. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
992.
993.
提出了一种单次可编程的金属-分子-金属器件. 该器件利用一种经过改良的Rotaxane LB膜作为功能层,可以和应用于场编程门阵列电路中的无机反熔丝器件相比拟,将在有机可编程电路和容错电路等方面有较广泛的应用. 所有的加工工艺都是低温工艺,使得该器件可以和其他有机器件集成. 电学测试表明该器件有良好的单次编程能力,其击穿电压为2.2V,关态电阻为15kΩ,而开态电阻为54Ω. 据分析,这一特性是由非对称的电极结构和金属原子在高电场作用下穿透了分子薄膜所造成的. 相似文献
994.
A number of defensive technologies have been proposed for the prevention of security threats. However, these defensive technologies are implemented independently without cooperation among various network domains. In this paper, different administrative networks are leagued to form a federative network environment called a trusted domain. From the perspective of a network manager, there is a need to integrate diverse technologies into an effective defensive system among mutually trusted domains. An imperative task for security management is to put in place a shared defensive mechanism, or protective shield, for multiple domains. A cooperative approach to provide such a shared defensive system is presented with integration of both intra‐domain and inter‐domain defensive mechanisms. The simulation results show that, through sharing the defensive information, the firewall system can successfully detect and filter the repeated intrusions. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
995.
This paper focuses on the benefits that organizations may achieve from their investment in enterprise systems (ES). It proposes an ES benefit framework for summarizing benefits in the years after ES implementation. Based on an analysis of the features of enterprise systems, on the literature on information technology (IT) value, on data from 233 enterprise systems vendor‐reported stories published on the Web and on interviews with managers of 34 organizations using ES, the framework provides a detailed list of benefits that have reportedly been acquired through ES implementation. This list of benefits is consolidated into five benefits dimensions: operational, managerial, strategic, IT infrastructure and organizational, and illustrated using perceived net benefit flow (PNBF) graphs. In a detailed example, the paper shows how the framework has been applied to the identification of benefits in a longitudinal case study of four organizations. 相似文献
996.
基于B／S结构的数据库加密研究 总被引：4，自引：0，他引：4
网络技术的快速发展,数据库的广泛应用,使得数据库安全技术研究已成为信息安全研究的主要课题之一。在对数据库加密技术进行研究的基础上,给出了一个基于B／S结构的数据库加密方案,并利用JSP技术实现了上述方案。理论分析和实验结果表明,该方案可以提高数据库系统的安全性能,并且实现简单。 相似文献
997.
基于Struts框架的Hibernate应用研究 总被引：2，自引：0，他引：2
本文介绍了struts框架的原理和结构,基于struts框架引入了一种新的对象/关系映射框架:Hibernate,研究和分析了Hibernate的应用。 相似文献
998.
999.
质量驱动产品开发方法及其应用研究 总被引：4，自引：0，他引：4
对质量驱动的产品开发方法进行了介绍,针对我国仪表行业新产品开发能力薄弱的现状和现代工业仪表设计技术,建立了仪表产品质量驱动的计算机辅助产品开发集成设计系统框架模型,指出该设计系统的关键是实现产品质量功能配置,生命周期故障模式与效应分析（ＦＭＥＡ）,及产品设计决策系统的集成设计。文末给出了应用实例。 相似文献
1000.
The time‐dependent Maxwell equations are one of the most important approaches to describing dynamic or wide‐band frequency electromagnetic phenomena. A sequential finite‐volume, characteristic‐based procedure for solving the time‐dependent, three‐dimensional Maxwell equations has been successfully implemented in Fortran before. Due to its need for a large memory space and high demand on CPU time, it is impossible to test the code for a large array. Hence, it is essential to implement the code on a parallel computing system. In this paper, we discuss an efficient and scalable parallelization of the sequential Fortran time‐dependent Maxwell equations solver using High Performance Fortran (HPF). The background to the project, the theory behind the efficiency being achieved, the parallelization methodologies employed and the experimental results obtained on the Cray T3E massively parallel computing system will be described in detail. Experimental runs show that the execution time is reduced drastically through parallel computing. The code is scalable up to 98 processors on the Cray T3E and has a performance similar to that of an MPI implementation. Based on the experimentation carried out in this research, we believe that a high‐level parallel programming language such as HPF is a fast, viable and economical approach to parallelizing many existing sequential codes which exhibit a lot of parallelism. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献