Target coverage problem in wireless sensor networks remains a challenge. Due to nonlinear nature, previous work has mainly focused on heuristic algorithms, which remain difficult to characterize and have no performanc...
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ISBN:
(纸本)9781424451142
Target coverage problem in wireless sensor networks remains a challenge. Due to nonlinear nature, previous work has mainly focused on heuristic algorithms, which remain difficult to characterize and have no performance guarantee. To solve the problem, this paper offers two important contributions. the first contribution is to have two lifetime upper bounds, which could be used to justify performance of previously proposed heuristic algorithms. One upper bound is based on the relaxation and reformulation technique while the other is derived by relaxing coverage constraints. We study the interesting connection between those two bounds and thus endow them with physical meanings. the second contribution is proposing a column generation based (CG) approach. the objective is to find an optimal schedule, defined as a time table specifying from what time up to what time which sensor watches which targets while the maximum lifetime has been obtained. We also offer an in-depththeoretic analysis as well as several novel techniques to further optimize the approach. Numerical results not only demonstrate that the lifetime upper bounds are very tight, but also verify that the proposed CG based approach constantly yields the optimal or near optimal solution.
Recently, Wireless sensor Networks (WSN) community has witnessed an application focus shift. Although, monitoring was the initial application of wireless sensor networks, in-network data processing and (near) real-tim...
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ISBN:
(纸本)9789639799592
Recently, Wireless sensor Networks (WSN) community has witnessed an application focus shift. Although, monitoring was the initial application of wireless sensor networks, in-network data processing and (near) real-time actuation capability have made wireless sensor networks suitable candidate for event detection and alarming applications as well. Unreliability and dynamic (e.g. in terms of deployment area, network resources, and topology) are normal practices in the field of WSN. therefore, effective and trustworthy event detection techniques for the WSN require robust and intelligent methods of mining hidden patterns in the sensor data, while supporting various kinds of dynamicity. Due to the fact that events are often functions of more than one attribute, data fusion and use of more features can help increasing event detection rate and reducing false alarm rate. In addition, sensor fusion can lead to more accurate and robust event detection by eliminating outliers and erroneous readings of individual sensor nodes and combining individual event detection decisions. In this paper, we propose a two-level sensor fusion-based event detection technique for the WSN. the first level of event detection in our proposed approach is conducted locally inside the sensor nodes, while the second level is carried out in a level higher (e.g., in a cluster head or gateway) and incorporates a fusion algorithm to reach a consensus among individual detection decisions made by sensor nodes. By considering fire as an event, we evaluate our approach through several experiments and illustrate impact of sensor fusion on achieving better results.
We study the capabilities of virtual addressing schemes for efficient and failure tolerant routing in sensor networks. In particular, we present the Virtual Cord Protocol (VCP) that uses techniques known from peer-to-...
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ISBN:
(纸本)9781424433742
We study the capabilities of virtual addressing schemes for efficient and failure tolerant routing in sensor networks. In particular, we present the Virtual Cord Protocol (VCP) that uses techniques known from peer-to-peer networks, i.e. distributed Hash Tables (DHTs) are used to associate data items in sensor networks with particular node addresses. the addresses of nodes are dynamically maintained by the protocol to form a virtual cord. VCP uses two mechanisms for finding paths to nodes and associated data items: First it relies on the virtual cord that always points towards the destination. Furthermore, locally available neighborhood information is exploited for greedy routing. Our simulation results show that VCP is able to find paths close to the possible shortest path with very low overhead. the routing performance of VCP, which clearly outperforms other ad hoc routing protocols such as Dynamic MANET On Demand (DYMO), is similar to other virtual addressing schemes, e.g. Virtual Ring Routing (VRR). However, we improved VCP to handle frequent node failures in an optimized way. the results presented in this paper outline the capabilities of VCP to handle such cases.
We define geometric self-structuring in a large-scale networked system as the ability of the participating nodes to collaboratively impose a geometric structure to the network. Self-structuring is hard to achieve when...
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ISBN:
(纸本)9783540922940
We define geometric self-structuring in a large-scale networked system as the ability of the participating nodes to collaboratively impose a geometric structure to the network. Self-structuring is hard to achieve when no global positioning information about the network is available. Yet this is an useful capability in networked autonomous systems such as sensor networks. In this paper, we present the design and the evaluation of a fully decentralized geometric self-structuring approach. this approach heavily relies on the ability of each node to estimate its position in the network. the contribution of the paper is twofold: (i) a simple and fully decentralized virtual coordinated system (VINCOS) is proposed, relying only on local connectivity information and per-neighbor communication;(ii) a network geometric self-structuring approach (NetGeoS) is presented that enables a large set of nodes to configure themselves in arbitrary geometric structures. the evaluation shows that the approach is both efficient and accurate while achieving the geometric structuring.
Wireless sensor network (WSN) has been considered to be the next generation paradigm of structural health monitoring (SHM) systems due to its low cost, high scalability and flexibility. However, some inherent limitati...
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Fast and periodic collection of aggregated data is of considerable interest for mission-critical and continuous monitoring applications in sensor networks. In the many-to-one communication paradigm known as convergeca...
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During the last two decades, starting withthe seminal work by Cruz, network calculus has evolved as a new theory for the performance analysis of networked systems. In contrast to classical queueing theory, it deals w...
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ISBN:
(纸本)9780769538082
During the last two decades, starting withthe seminal work by Cruz, network calculus has evolved as a new theory for the performance analysis of networked systems. In contrast to classical queueing theory, it deals with performance bounds instead of average values and thus has been the theoretical basis of quality of service proposals such as the IETF's Integrated and Differentiated Services architectures. Besides these it has, however, recently seen many other applications scenarios as, for example, wireless sensor networks, switched Ethernets, avionic networks, systems-on-Chip, or even to speed-up simulations, to name a few. In this paper, we extend network calculus by a new versatile modelling element: a demultiplexer. Conventionally, demultiplexing has either been neglected or assumed to be static, i.e., be fixed at the setup time of a network. this is restrictive for many potential applications of network calculus. For example a load balancing based on current link loads in a network could not be modelled with conventional network calculus means. Our demultiplexing element is based on stochastic scaling. Fundamental results on a network calculus with stochastic scaling are therefore derived in this work. We illustrate the benefits of the demultiplexer in the sample application of load balancing.
the purpose of this paper is to find and describe a suitable software framework that can be used to help implement the concept of a Generic Virtual Power Plant in the future power system. the Generic Virtual Power Pla...
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ISBN:
(纸本)9781424437702
the purpose of this paper is to find and describe a suitable software framework that can be used to help implement the concept of a Generic Virtual Power Plant in the future power system. the Generic Virtual Power Plant concept, along withthe utilization of distributed energy resources, has many interesting properties that can influence the future shape of power markets. the concept holds many promises including cheaper power to the consumer, a more flexible and responsive power production and the support of a more environment-friendly development. In order to realize a software solution supporting the Generic Virtual Power Plant, an array of different software design principles, patterns and architectures must be applied Especially Service Oriented Architecture (SOA) can aid in implementing the Generic Virtual Power Plant. An analysis of the Nordic power market has been carried out in order to identify potential issues and barriers, henceforth mentioned as challenges, connected withthe introduction of the Generic Virtual Power Plant concept.
作者:
Hortos, William S.
9143 Galleon Court Orlando FL 32819 United States
the real-time interactions among the nodes of a wireless sensor network (WSN) to cooperatively process data from multiple sensors are modeled. Quality-of-service (QoS) metrics are associated withthe quality of fused ...
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ISBN:
(纸本)9789639799592
the real-time interactions among the nodes of a wireless sensor network (WSN) to cooperatively process data from multiple sensors are modeled. Quality-of-service (QoS) metrics are associated withthe quality of fused information: throughput, delay, packet error rate, etc. Multivariate point process (MVPP) models of discrete random events in WSNs establish stochastic characteristics of optimal cross-layer protocols. In previous work, discrete-event, cross-layer interactions in mobile ad hoc network (MANET) protocols have been modeled using a set of concatenated design parameters and associated resource levels by the MVPPs. Characterization of the "best" cross-layer designs for a MANET is formulated by applying the general theory of martingale representations to controlled MVPPs. Performance is described in terms of concatenated protocol parameters and controlled through conditional rates of the MVPPs. Assumptions on WSN characteristics simplify the dynamic programming conditions to yield mathematically tractable descriptions for the optimal routing protocols. Modeling limitations to determination of closed-form solutions versus explicit iterative solutions for ad hoc WSN controls are examined.
We study the problem of covering a two-dimensional spatial region P, Cluttered with occluders, by sensors. A sensor placed at a location p covers a point x in P if x lies within sensing radius r from p and x is visibl...
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ISBN:
(纸本)9783642020841
We study the problem of covering a two-dimensional spatial region P, Cluttered with occluders, by sensors. A sensor placed at a location p covers a point x in P if x lies within sensing radius r from p and x is visible from p, i.e., the segment px does not intersect any occluder. the goal is to compute a placement of the minimum number of sensors that cover P. We propose a landmark-based approach for covering P. Suppose P has,;holes, and it can be covered by h sensors. Given a small parameter epsilon > 0, let lambda := lambda(h, epsilon) = (h/epsilon)(1 + ln (1 + zeta)). We prove that one can compute a set L of O(lambda log lambda log (1/epsilon)) landmarks so that if a set S of sensors covers L, then S covers at least (1 - epsilon)-fraction of P. It is surprising that so few landmarks are needed, and that the number of landmarks depends only on h, and does not directly depend on the number of vertices in P. We then present efficient randomized algorithms, based on the greedy approach, that, with high probability, compute O(h log A) sensor locations to cover L;here (h) over tilde <= h is the number sensors needed to cover L. We propose various extensions of our approach, including: (i) a weight function over P is given and S should cover at least (1 - epsilon) of the weighted area of P, and (ii) each point of P is covered by at least t sensors, for a given parameter t >= 1.
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