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961.
An event-triggered control(ETC) system transmits data packages and updates control inputs only when the predefined criterion is satisfied. In this way, network communication and computing resources are scheduled more reasonably in contrast to the traditional periodic sampling strategy.Small-gain approach proposed in recent literatures is a new modeling method to deal with nonlinear ETC systems. Different from traditional ETC models, stability criteria are proposed in the form of input to state stability(ISS) gain to design the triggering mechanisms. This paper introduces additional dynamic variables in this model and proposes a small-gain based dynamic event-triggered strategy.Sufficient conditions to guarantee the stability of the system are derived with the help of cyclic-smallgain theorem and Zeno behaviors are avoided to ensure the feasibility of this method in practical applications. Numerical simulations are given to demonstrate the effectiveness of our approach. 相似文献
962.
As a representative emerging financial market, the Chinese stock market is more prone to volatility because of investor sentiment. It is reasonable to use efficient predictive methods to analyze the influence of investor sentiment on stock price forecasting. This paper conducts a comparative study about the predictive performance of artificial neural network, support vector regression (SVR) and autoregressive integrated moving average and selects SVR to study the asymmetry effect of investor sentiment on different industry index predictions. After studying the relevant financial indicators, the results divide the Shenwan first-class industries into two types and show that the industries affected by investor sentiment are composed of young companies with high growth and high operative pressure and there are a great number of investment bubbles in those companies. 相似文献
963.
There is overwhelming evidence that anthropogenic activity has exerted a great influence on climate extremes, especially on heat events at continental to global... 相似文献
964.
数据的完整性是指数据库中数据的正确性、有效性和一致性。完整性约束条件是完整性控制机制的核心。在SQL Server数据库应用系统中,有多种方法进行数据的完整性保护,应根据各种完整性约束的优点将它们结合起来使用,充分发挥SQLServer提供的数据完整性的效能,确保数据准确性和一致性。 相似文献
965.
966.
Wheeled foot quadruped robot HITAN-I 总被引:2,自引:0,他引:2
0IntroductionInthe past,much work has been done toinvestigatefour-legged walking.Two of the earliest works are the G.E.Quadruped and Phoney[1].With the introduction ofmore powerful computers,more and more bionic robotshave beeninvented in recent years.WARP1[2]in2002,TITAN[3-5]from1989,BISAM[6]in1998and SCOUTII[7]in1999are examples for these developments.Asground vehicle,the advantages of mobile robot have beenrecognized by peopleinengineeringfields.Ground mobilerobots are usually cl… 相似文献
967.
舰船工作环境常导致备件的实际可靠性规律与设计参数不一致。在实际使用消耗量较小的条件下,全面分析备件可靠性信息来源,通过定义似然权重系数,融合多源先验信息,建立指数型备件可靠性的贝叶斯评估方法。最后,通过仿真分析验证方法的合理性。结果表明,所提出的基于似然权重的先验信息融合方法可以较好地融合不同信息源的可靠性信息,估计方法具有较好的稳定性。 相似文献
968.
In this article, an optimal switching integrity attack problem is investigated to study the response of feedback control systems under attack. The authors model the malicious attacks on sensors as additive norm bounded signals. The authors consider an attacker who is only capable of launching attacks to limited number of sensors once a time and changing the combinations of attacked sensors all over the time. The objective of this paper is to find the optimal switching sequence of these combinations and the optimal attack input. The authors solve this problem by transforming it into a traditional optimal control problem with new control variables vary continuously in the range [0, 1]. The optimal solutions of the new control variables are of bang-bang-type. Therefore, an algebraic switching condition and an optimal attack input can be obtained. Finally, numerical results are provided to illustrate the effectiveness of the methods. 相似文献
969.
Journal of Systems Science and Complexity - Weispfenning in 1992 introduced the concepts of comprehensive Gröbner system/basis of a parametric polynomial system, and he also presented an... 相似文献
970.