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李勇 《自动化技术与应用》2020,39(3):51-55
随着操作系统国产化的浪潮,麒麟系统已开始应用于各行各业,但是麒麟系统还没有一个便捷的即时通讯系统。本文旨在设计能在麒麟系统下运行的即时通讯系统。由于麒麟系统是基于Linux内核开发的,本文采用QT开发平台,设计并实现了一套即时通讯系统。此系统采用oracle数据库和RSA加密技术,既能解决麒麟系统下即时通讯问题,又保证了通讯安全。经测试,系统能够稳定运行。 相似文献
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根据衡敛状态方程,系统输入或边界条件的变化能够影响系统状态,对于系统状态出现的衰减湮灭,推导了系统衰减湮灭的状态方程、衰灭平衡方程。得出,当系统状态发生衰减湮灭,系统状态值、系统输入值、边界条件之间相互作用,改变系统的输入或边界条件能够恢复系统。应用系统衰灭状态方程及衰灭平衡方程,对系统状态变化进行分析,是研究系统状态演变,系统控制,状态时滞、预防系统性衰减的方法。 相似文献
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本文介绍了基于CDMA的停车场车位引导系统的设计方案,阐述了系统软硬件设计、CDMA主要特点及接口电路图。该系统采用CDMA无线通信模块,使系统性能更加完善。实验结果表明本系统与485通信系统、CAN总线通信系统相比,通信距离和通信速率明显提高。本系统避免了一路出错导致整个系统瘫痪的问题,使停车场车位引导系统更加智能化。 相似文献
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王天佟 《计算机光盘软件与应用》2014,(15):38+40
本文通过分析了传统医院叫号服务系统存在的一些弊端问题,着重介绍了基于安卓系统的医院排队叫号体统,此叫号系统比传统的医院叫号系统优势明显,而且可行性非常的高。此外,本文还介绍了安卓系统开发环境的构建,共分为医院排号系统与医院挂号系统以及排队叫号的系统三个流程。重点讲述安卓系统的医院排号系统。 相似文献
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嵌入式Email系统是类PC嵌入式系统,是嵌入式操作系统及其应用软件的一个重要组成部分,但是现有PC上的嵌入式Email系统都不能适应类PC嵌入式系统的硬件环境要求。文中采用了一种新的构建嵌入式Email系统的方法,设计与实现了清华嵌入式Email系统,可根据各种类PC嵌入式系统的不同要求进行定制。首先,论述了类PC嵌入式系统的硬件平台对嵌入式Email系统的苛刻要求,其次,描述了清华嵌入式Email系统的体系结构,接着,讨论了清华嵌入式Email系统的实现机制与原理,以及系统模型,最后,给出了嵌入式Email系统的特点。由于采用了现在流行的一种开放源码的组件,使得整个系统功能完善,并能够完全符合类PC嵌入式系统的要求。嵌入式Email系统已经在自主研制的掌上电脑HPC和交互式网络电视上成功地运行。 相似文献
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随着系统变得越发复杂和庞大,故障的出现会直接或间接影响系统的性能,因此,针对故障系统的研究越来越引起学者们的关注。针对故障系统的故障特点,将故障系统分为执行器故障系统和传感器故障系统,并进一步分别概括出现有执行器故障系统和传感器故障系统的状态估计方法。针对每种系统的基本特点,分别介绍了相应的状态估计研究进展,适用条件和应用范围。最后综述了故障系统状态估计方法目前诚待解决的问题。 相似文献
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在系统与系统的交互过程中,很多系统都无法实现系统与系统间操作的实时交互性以及数据的同步性,而需要通过接口系统采用跑批的方式来实现系统间数据的同步性。该文介绍一种实时交互的组件――Link-easy的实现,该组件可以解决系统与系统之间的实时交互问题。 相似文献
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对人口系统的讨论 ,通常的数学模型没有考虑外界环境对系统的影响 .在假设随机的外界环境对迁移产生扰动的条件下 ,给出Hilbert空间中一类随机时变人口发展系统 .对随机时变人口发展系统的均方稳定性和指数稳定性进行了讨论 .利用Burkholder_Davis_Gundy不等式 ,Gronwall引理和Kolmogorov不等式得到了均方稳定和指数稳定的充分条件 .最后提出如果生育率选作控制变量 ,系统仍然是均方和指数稳定的 ,并可进一步讨论它的最优控制问题 相似文献
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Shen Cong 《International journal of systems science》2014,45(9):1927-1935
Most of the existing results on the stability problem of delayed singular systems only pertain to the case of constant delay. This is due to the fact that time-varying delay makes it hardly possible to explicitly express the fast variables. In this paper, aiming at dealing with the case of time-varying delay, we create a way to prove the stability by using a perturbation approach. Rather, we first get the decay rate for slow variables by using Lyapunov functional approach and, furthermore, guarantee that the fast variables fall into decay by characterising their effect on the derived decay rate. Also, we present a convexity technique in computing the constructed Lyapunov functional which contributes to the elimination of the possible conservatism caused by the varying rate of delay. Finally, we provide two numerical examples to demonstrate the effectiveness of the method. 相似文献
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Tai-Fang Li Georgi M. Dimirovski Yanyan Liu 《International journal of systems science》2013,44(6):1076-1088
This article is concerned with the stability analysis for a class of switched neutral systems with mixed time-varying delays. The upper bound of derivative of the discrete time-varying delay is not restricted to one. A delay-dependent criterion of exponential stability under switching signals with an average dwell time is developed by employing free weighting matrices. The criterion is given in the form of linear matrix inequality. A state decay estimation for the switched system is explicitly given by considering the individual rate of decay of state for each subsystem. Two simulation examples are given to illustrate the effectiveness of the proposed method. 相似文献
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This paper investigates the problem of exponential stability and l1‐gain performance analysis for a class of discrete‐time switched positive singular systems with time‐varying delay. Firstly, a necessary and sufficient condition of positivity for the system is established by using the singular value decomposition method. Then by constructing an appropriate co‐positive Lyapunov functional and using the average dwell time scheme, we develop a sufficient delay‐dependent condition and identify a class of switching signals for the switched positive singular system to be exponentially stable and meet a prescribed l1‐gain performance level under the switching signal. Based on this condition, the decay rate of the system can be tuned and the optimal system performance level can be determined by solving a convex optimization problem. All of the criteria obtained in this paper are presented in terms of linear programming, which suggests a good scalability and applicability to high dimensional systems. Finally, a numerical example is presented to demonstrate the effectiveness of the proposed method. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Baozhu Guo Cheng-Zhong Xu 《Automatic Control, IEEE Transactions on》2000,45(1):89-93
We show that the spectrum-determined growth condition holds for the closed-loop system of a vibration cable with a tip mass and linear boundary feedback control. The optimal decay rate of the energy for a case left unsolved previously is determined, and the asymptotic expansion of the associated semigroup is obtained. As a consequence of the approach, we show, in a different point of view, the lack of uniform exponential stability of the system with only boundary velocity feedback control 相似文献
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本语文针对一般的滞后动态系统建立了广义指数稳定性的充分和必要条件,并由所建立的充要条件得出了系统过渡过程的时变指数衰减估计,作为所建结果的应用,基于矩阵工给出了一类滞后动态系统过渡过程的相应指数衰减估计,本文揭示了所建衰减估计可好于那些仅基于充分稳定性条件所得的估计。 相似文献
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非完整向量幂式系统的光滑时变指数镇定 总被引:2,自引:1,他引:1
研究非完整向量幂式系统的镇定问题,通过引入一个辅助状态变量,此类系统可将转换成一个线性时变系统,由此可得至具有指数收敛率的光滑反馈控制律。该方法优点是控制律光滑并且设计过程简单,系统每个状态的收敛率可被事先确定。仿真结果表明,仿真结果表明了该方法的有效性。 相似文献
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Jianhong Zhang 《Asian journal of control》2014,16(6):1820-1828
This paper studies the robust exponential stability of uncertain discrete linear time‐varying (UDLTV) systems. The key tool is the recently proposed generating functions. It can be found that a class of improved generating functions (IGFS) can fully characterize the robust exponential stability of UDLTV systems, and the maximum exponential decay rate of system trajectories can be computed by the radius of convergence of the IGFS. Moreover, the application of convex optimization technique and dynamic programming method provides an effective algorithm for the computation of the IGFS. Finally, the numerical example illustrates the efficacy and advantage of the proposed approach. 相似文献