共查询到20条相似文献,搜索用时 15 毫秒
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ABSTRACTThis paper proposes an integral-based event-triggered control strategy to solve the consensus problem of multi-agent systems with general linear dynamics. We first consider the leader-following consensus problem where the communication topology has a directed spanning tree with the leader as the root. It is proved that under the proposed strategy leader-following consensus is guaranteed and the inter-event intervals are lower bounded by positive constants. Then, the leaderless consensus problem of multi-agent systems is investigated under directed topology. We show that consensus is achieved and no Zeno behaviour occurs. Simulation results verify the effectiveness of the obtained results. 相似文献
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研究一类具有测量数据随机丢失以及网络拓扑结构随机切换的分布式$l_2-l_\infty$滤波器设计问题.在分布式滤波器网络,每个本地滤波器估计系统的状态不仅基于节点自身信息,而且利用网络拓扑中邻居节点的信息.首先,采用已知概率分布的二进制序列描述传感器测量数据的随机丢失,Markov链描述滤波器网络拓扑结构的切换;其次,构造一个Lyapunov函数来分析滤波误差系统的$l_2-l_\infty$性能,并研究其均方指数稳定性;再次,通过线性矩阵不等式(LMI)技术,给出分布式$l_2-l_\infty$滤波器的设计方法;最后, 通过数值例子验证所提方法的有效性. 相似文献
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This paper develops the observation control method for refining the Kalman–Bucy estimates, which is based on impulsive modeling of the transition matrix in an observation equation, thus engaging discrete-continuous observations. The impulse observation control generates on-line computable jumps of the estimate variance from its current position towards zero and, as a result, enables us to instantaneously obtain the estimate, whose variance is closer to zero. The filtering equations over impulse-controlled observations are obtained in the Kalman–Bucy filtering problem. The method for feedback design of control of the estimate variance is developed. First, the pure impulse control is used, and, next, the combination of the impulse and continuous control components is employed. The considered examples allow us to compare the properties of these control and filtering methodologies. 相似文献
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Set-membership filtering for systems with sensor saturation 总被引:2,自引:0,他引:2
This paper addresses the set-membership filtering problem for a class of discrete time-varying systems with sensor saturation in the presence of unknown-but-bounded process and measurement noises. A sufficient condition for the existence of set-membership filter is derived. A convex optimisation method is proposed to determine a state estimation ellipsoid that is a set of states compatible with sensor saturation and unknown-but-bounded process and measurement noises. A recursive algorithm is developed for computing the ellipsoid that guarantees to contain the true state by solving a time-varying linear matrix inequality. Simulation results are provided to demonstrate the effectiveness of the proposed method. 相似文献
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Michael J. WALSH Anthony FEE John BARTON Brendan O''Flynn Brendan O’FLYNN Martin J. HAYES Cian O''Mathun Cian O’MATHUNA 《控制理论与应用(英文版)》2011,9(1):083-092
A hybrid methodology is proposed for use in low power, safety critical wireless sensor network applications, where quality-of-service orientated transceiver output power control is required to operate in parallel with radio frequency-based localization. The practical implementation is framed in an experimental procedure designed to track a moving agent in a realistic indoor environment. An adaptive time synchronized approach is employed to ensure the positioning technique can operate effectively in the presence of dataloss and where the transmitter output power of the mobile agent is varying due to power control. A deterministic multilateration-based positioning approach is adopted and accuracy is improved by filtering signal strength measurements overtime to account for multipath fading. The location estimate is arrived at by employing least-squares estimation. Power control is implemented at two separate levels in the network topology. First, power control is applied to the uplink between the tracking reference nodes and the centralized access point. A number of algorithms are implemented highlighting the advantage associated with using additional feedback bandwidth, where available, and also the need for effective time delay compensation. The second layer of power control is implemented on the uplink between the mobile agent and the access point and here quantifiable improvements in quality of service and energy efficiency are observed. The hybrid paradigm is extensively tested experimentally on a fully compliant 802.15.4 testbed, where mobility is considered in the problem formulation using a team of fully autonomous robots. 相似文献
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Filtering is a generic technique for skyline retrieval in sensor networks, for the purpose of reducing the communication cost, the dominant part of energy consumption. The vast majority of existing filtering approaches are suitable for uniform and correlated datasets, whereas in many applications the data distribution is clustered or anti-correlated. The only work considering anti-correlated dataset requires significant energy for filtering construction, and it is hard to be efficiently adapted to clustered databases. In this paper, we propose a new filtering algorithm, which settles the problem by utilizing individual node characteristics and generating personalized filters. Given a fraction k, a personalized filter prunes at least k percent of points on assigned nodes. A novel scheme for data cluster representation and a sampling method are then proposed to reduce the filtering cost and maximize the benefit of filtering. Extensive simulation results show the superiority of our approach over existing techniques. 相似文献
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In this paper, the problem of robust distributed H∞ filtering is investigated for state‐delayed discrete‐time linear systems over a sensor network with multiple fading measurements, random time‐varying communication delays, and norm‐bounded uncertainties in all matrices of the system. The diagonal matrices, whose elements are individual independent random variables, are utilized to describe the multiple fading measurements. Furthermore, the Bernoulli‐distributed white sequences are introduced to model the random occurrence of time‐varying communication delays. In the proposed filtering approach, the stability of the estimation error system is first shown by the Lyapunov stability theory and the H∞ performance is then achieved using a linear matrix inequality method. Finally, two numerical examples are given to show the effectiveness and performance of the proposed approach. 相似文献
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针对无线传感器网络迭代定位算法中节点定位精确度低的问题,提出了协同过滤定位算法(Cooperative Filter Localization Algorithm, CFLA)。该算法对周围只有两个信标节点的未知节点进行定位时,产生出未知节点的两个候选点。为了精准高效地判定出候选点,引入两种协同过滤定位模型。模型一,通过选择出合理的参考节点,利用该参考节点与未知节点的协作进行候选点的过滤。模型二,利用该模型中可以直接通信的未知节点之间的相互协作,判定它们之间的测距与它们的候选点间的欧式距离之间的关系过滤出精度高的候选点。仿真结果表明,在相同的网路环境下,CFLA算法在能量消耗上低于SL-n和RAMP;在信标节点占比为8%时,该算法的定位误差比SL-n算法减少了14.7%,比RAMP算法减少了9.6%,有效地提高了节点的定位精度。 相似文献
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本文主要研究无线传感器网络中目标数目已知且固定的一类分布式多目标跟踪问题,提出了一种完全分布式的基于事件触发的测量和通信策略使得每个节点在不需要全局信息的情况下实现估计误差和能量消耗之间的平衡.监测区域存在多个移动目标,传感器能否测量到单个目标由事件触发测量机制和节点的测量半径来综合决定.基于节点和邻居的信息采用k-means聚类算法来解决数据关联问题,同时提出了基于最小迹原则的一致性卡尔曼滤波算法.从理论上证明了该事件触发策略不仅在性能指标上优于基于时间触发的算法,而且在网络中如果存在节点对多目标协同可观,系统估计误差在均方意义下是稳定的.最后给出了仿真例子验证了该算法的有效性和可行性. 相似文献
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Stochastic modelling of insulin sensitivity and adaptive glycemic control for critical care 总被引:2,自引:0,他引:2
Lin J Lee D Chase JG Shaw GM Le Compte A Lotz T Wong J Lonergan T Hann CE 《Computer methods and programs in biomedicine》2008,89(2):141-152
Targeted, tight model-based glycemic control in critical care patients that can reduce mortality 18-45% is enabled by prediction of insulin sensitivity, S(I). However, this parameter can vary significantly over a given hour in the critically ill as their condition evolves. A stochastic model of S(I) variability is constructed using data from 165 critical care patients. Given S(I) for an hour, the stochastic model returns the probability density function of S(I) for the next hour. Consequently, the glycemic distribution following a known intervention can be derived, enabling pre-determined likelihoods of the result and more accurate control. Cross validation of the S(I) variability model shows that 86.6% of the blood glucose measurements are within the 0.90 probability interval, and 54.0% are within the interquartile interval. "Virtual Patients" with S(I) behaving to the overall S(I) variability model achieved similar predictive performance in simulated trials (86.8% and 45.7%). Finally, adaptive control method incorporating S(I) variability is shown to produce improved glycemic control in simulated trials compared to current clinical results. The validated stochastic model and methods provide a platform for developing advanced glycemic control methods addressing critical care variability. 相似文献
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A common approach to improve the reliability of query results based on error-prone sensors is to introduce redundant sensors. However, using multiple sensors to generate the value for a data item can be expensive, especially in wireless environments where continuous queries are executed. Moreover, some sensors may not be working properly and their readings need to be discarded. In this paper, we propose a statistical approach to decide which sensor nodes to be used to answer a query. In particular, we propose to solve the problem with the aid of continuous probabilistic query (CPQ), which is originally used to manage uncertain data and is associated with a probabilistic guarantee on the query result. Based on the historical data values from the sensor nodes, the query type, and the requirement on the query, we present methods to select an appropriate set of sensors and provide reliable answers for several common aggregate queries. Our statistics-based sensor node selection algorithm is demonstrated in a number of simulation experiments, which shows that a small number of sensor nodes can provide accurate and robust query results. 相似文献
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已有传感器网络虚假数据过滤机制采用随机策略部署节点,由转发节点对数据包中附带的t个MAC(Message Authentication Code)签名进行验证,从而实现对虚假数据的识别和过滤。然而,在实际应用中,随机部署往往在网络中形成部分稀疏区域,无法被t个拥有不同密钥分区的节点同时覆盖。提出利用覆盖算法对节点进行部署,在均衡覆盖质量及网络开销的情况下,证明了适用于虚假数据过滤的最优节点覆盖度为2t,并进一步推导了一些相关的覆盖结论。理论分析及仿真实验表明,与随机部署相比,最优覆盖算法极大提高t个密钥分区同时覆盖的概率。例如,当400个节点部署于50?50m2的区域时,随机部署和最优覆盖算法保证t个密钥分区同时覆盖的概率分别为9%和92%。 相似文献
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虚假数据注入攻击是无线传感器网络的一种严重威胁,针对大多数虚假数据过滤方案没考虑节点身份攻击和中间节点被攻击者俘获的问题,提出了一种抗节点身份攻击的虚假数据过滤方案,方案不仅在数据转发过程中对转发的数据进行验证、过滤,同时对协作产生感知数据的节点的身份进行验证。安全性分析和性能评价表明,该方案不仅能抵抗各种攻击,而且在存储开销方面与其他方案相比,具有明显优势,并且随着数据包被转发跳数的增加,该方案的虚假数据过滤能力和能量节省也显著增加。 相似文献
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In this paper, a new reliable H-infinity filter design problem is proposed for a class of continuous-time systems with sensor saturation and failures. Attention is focused on the analysis and synthesis problems of a full order reliable H-infinity filter such that the filtering error dynamics is asymptotically stable with a guaranteed disturbance rejection attenuation level γ. It is shown that the filtering error dynamics obtained from the original system plus the filter can be modeled by a linear system with sector bounded nonlinearity. The design conditions are given in terms of solutions to a set of linear matrix inequalities (LMIs). These conditions are then considered in a convex optimization problem with LMIs constraints in order to design an optimal reliable H-infinity filter. A numerical example is given to illustrate the effectiveness of the proposed results. 相似文献