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24
Opportunitybased topology control in wireless sensor networks
 in ICDCS
, 2008
"... Topology control is an effective method to improve the energy efficiency of wireless sensor networks (WSNs). Traditional approaches are based on the assumption that a pair of nodes is either “connected ” or “disconnected”. These approaches are called connectivitybased topology control. In real envi ..."
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Cited by 139 (21 self)
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Topology control is an effective method to improve the energy efficiency of wireless sensor networks (WSNs). Traditional approaches are based on the assumption that a pair of nodes is either “connected ” or “disconnected”. These approaches are called connectivitybased topology control. In real environments however, there are many intermittently connected wireless links called lossy links. Taking a succeeded lossy link as an advantage, we are able to construct more energyefficient topologies. Towards this end, we propose a novel opportunitybased topology control. We show that opportunitybased topology control is a problem of NPhard. To address this problem in a practical way, we design a fully distributed algorithm called CONREAP based on reliability theory. We prove that CONREAP has a guaranteed performance. The worst running time is O(E) where E is the link set of the original topology, and the space requirement for individual nodes is O(d) where d is the node degree. To evaluate the performance of CONREAP, we design and implement a prototype system consisting of 50 Berkeley Mica2 motes. We also conducted comprehensive simulations. Experimental results show that compared with the connectivitybased topology control algorithms, CONREAP can improve the energy efficiency of a network up to 6 times. 1
Topology Control in Ad hoc Wireless Networks with Hitchhiking
, 2004
"... In this paper, we address the Topology Control with Hitchhiking (TCH) problem. Hitchhiking [1] is a novel model introduced recently that allows combining partial messages to decode a complete message. By effective use of partial signals, a specific topology can be obtained with less transmission ..."
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Cited by 27 (1 self)
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In this paper, we address the Topology Control with Hitchhiking (TCH) problem. Hitchhiking [1] is a novel model introduced recently that allows combining partial messages to decode a complete message. By effective use of partial signals, a specific topology can be obtained with less transmission power. The objective of the TCH problem is to obtain a stronglyconnected topology with minimum total energy consumption. We prove the TCH problem to be NPcomplete and design a distributed and localized algorithm (DTCH) that can be applied on top of any symmetric, stronglyconnected topology to reduce total power consumption. We analyze the performance of our approach through simulation.
Toward worm detection in online social networks
 In Proceedings of the 25th Annual Computer Security Applications Conference (ACSAC
, 2010
"... Worms propagating in online social networking (OSN) websites have become a major security threat to both the websites and their users in recent years. Since these worms exhibit unique propagation vectors, existing Internet worm detection mechanisms cannot be applied to them. In this work, we propose ..."
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Cited by 15 (0 self)
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Worms propagating in online social networking (OSN) websites have become a major security threat to both the websites and their users in recent years. Since these worms exhibit unique propagation vectors, existing Internet worm detection mechanisms cannot be applied to them. In this work, we propose an early warning OSN worms detection system, which leverages both the propagation characteristics of these worms and the topological properties of online social networks. Our system can effectively monitor the entire social graph by keeping only a small number of user accounts under surveillance. Moreover, the system applies a twolevel correlation scheme to reduce the noise from normal user communications such that infected user accounts can be identified with a higher accuracy. Our evaluation on the real social graph data obtained from Flickr indicates that by monitoring five hundreds users out of 1.8 million users, the proposed detection system can detect the burst of an OSN worm when less than 0.13 % of total user accounts are infected. Besides, by adopting simple countermeasures, the detection system is also shown to be very helpful for worm containment.
A Generalized Probabilistic Topology Control for Wireless Sensor Networks
"... Abstract—Topology control is an effective method to improve energyefficiency and increase the capacity in Wireless Sensor Networks (WSNs). It reduces the transmitting power of network nodes while the key network connectivity is preserved. In traditional approaches, networks are modeled using a dete ..."
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Abstract—Topology control is an effective method to improve energyefficiency and increase the capacity in Wireless Sensor Networks (WSNs). It reduces the transmitting power of network nodes while the key network connectivity is preserved. In traditional approaches, networks are modeled using a deterministic approach that assumes a pair of nodes are either connected or disconnected. In practice, however, most wireless links are lossy links that provide probabilistic connectivity only. To fully characterize WSNs with lossy links, we propose a novel probabilistic network model. Under this model, we meter the network quality using network reachability defined as the minimal of the upper limit of the endtoend delivery ratio between any pair of nodes in the network.We attempt to find a minimal transmitting power for each node while the network reachability is above a given applicationspecified threshold, called probabilistic topology control (PTC). We prove that PTC is NPhard and propose a fully distributed algorithm called BRASP. We prove that BRASP has the guaranteed performance. Two rules that must be followed by any algorithm for PTC have been identified. BRASP has the promising features on the overhead. The communication overhead is O(E  + V ), the worst running time is O(E), and the space requirement is O(1) where E is the set of links and V is the set of nodes. We conduct both simulations and prototype implementations based an 18TelosBnode testbed. The experimental results show that the network energyefficiency can be improved by up to 250%. The average node degree is reduced by 50 % which will lead to a great benefit for the network capacity.
A3: A Topology Construction Algorithm for Wireless Sensor Network
 IEEE Globecom
, 2008
"... Abstract — Topology control is a wellknown strategy to save energy and extend the lifetime of wireless sensor networks. This paper introduces the A3 (a tree) algorithm, a simple, distributed, and energyefficient topology construction mechanism that finds a suboptimal Connected Dominating Set (CD ..."
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Abstract — Topology control is a wellknown strategy to save energy and extend the lifetime of wireless sensor networks. This paper introduces the A3 (a tree) algorithm, a simple, distributed, and energyefficient topology construction mechanism that finds a suboptimal Connected Dominating Set (CDS) to turn unnecessary nodes off while keeping the network connected and providing complete communication coverage. A3 utilizes a weighted distanceenergybased metric that permits the network operator to trade off the lengths of the branches (distance) for the robustness and durability of the tree (energy). Comparisons with other wellknown topology construction mechanisms show the superiority of the proposed scheme in terms of the number of active nodes and energy efficiency. Simulation experiments show that to achieve complete communication coverage, A3 needs only 6 % and 41 % of the nodes active in dense and sparse scenarios,
Topology maintenance: Extending the lifetime of wireless sensor networks
 Proc. of WWASN 2009 (submitted
, 2009
"... Abstract—Topology control is a wellknown strategy to save energy and extend the lifetime of wireless sensor networks. In the literature, it is usually referred as the process that, given a set of nodes, builds a reduced topology that still guarantees connectivity and coverage. Here, we extend this ..."
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Abstract—Topology control is a wellknown strategy to save energy and extend the lifetime of wireless sensor networks. In the literature, it is usually referred as the process that, given a set of nodes, builds a reduced topology that still guarantees connectivity and coverage. Here, we extend this definition. We consider topology control as two processes: topology construction and topology maintenance. Topology construction encompasses those algorithms that build the reduced topology. Topology maintenance is the process that changes the reduced topology from time to time when the current one is no longer optimal. In this paper we define topology maintenance and present different strategies and triggering criteria that can be used to switch the network topology. We also implement static and dynamic global topology maintenance strategies using two wellknown topology construction algorithms and time and energybased triggering criteria, and compare their performance via simulations on sparse and dense networks. Our results demonstrate that the appropriate use of topology maintenance techniques extends the network lifetime versus the option of not doing topology maintenance at all. In sparse networks, while dynamic global techniques improve the network lifetime, static techniques may improve or degrade the performance. However, all results are fairly similar. On the other hand, topology maintenance is very well justified in dense networks where important performance improvements can be achieved. In this case, the superiority of dynamic global techniques is evident, and even more as the density of the network increases. I.
Sinkanonymity mobility control in wireless sensor networks
 IEEE International Conference on Wireless and Mobile Computing (Morocco, Networking and Communications
, 2009
"... Abstract—As the technology of mobile sensors advances, mobility control becomes a viable option that can be utilized to minimize energy consumption in wireless sensor networks (WSNs). A mobility control protocol redeploys mobile sensors to optimal positions to minimize energy consumption for comm ..."
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Abstract—As the technology of mobile sensors advances, mobility control becomes a viable option that can be utilized to minimize energy consumption in wireless sensor networks (WSNs). A mobility control protocol redeploys mobile sensors to optimal positions to minimize energy consumption for communication. We identify a unique privacy issue in mobility control protocols that discloses the physical location of the sink node to intruders in WSNs. To protect the sink node, we propose a new privacypreserving scheme to secure mobility control protocols against attacks that locate and sabotage the sink node. The privacypreserving scheme obfuscates the sink location with dummy sink nodes. Analysis shows that the scheme can effectively hide the sink location via anonymity. The scheme can also be easily integrated into current mobility control protocols without raising much additional overhead. The performance simulation and
Quick convergence mobility control schemes in wireless sensor networks
 Proceedings of IEEE international
, 2008
"... In the near future, wireless sensor networks (WSN) performing sensing and communication tasks will be widely deployed as technology rapidly advances. Communication is one of the essential functionalities of these mobile networks while power and computation resources in each sensor are limited. Rec ..."
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In the near future, wireless sensor networks (WSN) performing sensing and communication tasks will be widely deployed as technology rapidly advances. Communication is one of the essential functionalities of these mobile networks while power and computation resources in each sensor are limited. Recently, attention has been drawn to using mobility control to minimize energy consumption in wireless sensor networks. In this paper, we are going to provide quick convergence mobility control schemes to achieve optimal configuration in a single data flow. The key idea of our schemes is to use the optimal location information of each relay node as a guide for node movement while maintaining the connectivity of relay nodes along the data flow. Experimental results show that our schemes can speed up the convergence process to nearly the optimal and reduce the cost of it almost to the minimum, compared with the best results known to the date. 1
Extended dominating set in ad hoc networks using cooperative communication
 In IFIP Networking
, 2005
"... Abstract. We propose a notion of extended dominating set whereby each node in an ad hoc network is covered by either a dominating neighbor or several 2hop dominating neighbors. This work is motivated by cooperative communication in ad hoc networks where transmitting independent copies of a packet ..."
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Abstract. We propose a notion of extended dominating set whereby each node in an ad hoc network is covered by either a dominating neighbor or several 2hop dominating neighbors. This work is motivated by cooperative communication in ad hoc networks where transmitting independent copies of a packet generates diversity and combats the effects of fading. In this paper we propose several efficient heuristic algorithms for constructing a small extended dominating set.
Randomwalk Domination in Large Graphs
"... Abstract—We introduce and formulate two types of randomwalk domination problems in graphs motivated by a number of applications in practice (e.g., itemplacement problem in online social networks, Adsplacement problem in advertisement networks, and resourceplacement problem in P2P networks). Spec ..."
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Abstract—We introduce and formulate two types of randomwalk domination problems in graphs motivated by a number of applications in practice (e.g., itemplacement problem in online social networks, Adsplacement problem in advertisement networks, and resourceplacement problem in P2P networks). Specifically, given a graph G, the goal of the first type of randomwalk domination problem is to target k nodes such that the total hitting time of an Llength random walk starting from the remaining nodes to the targeted nodes is minimized. The second type of randomwalk domination problem is to find k nodes to maximize the expected number of nodes that hit any one targeted node through an Llength random walk. We prove that these problems are two special instances of the submodular set function maximization with cardinality constraint problem. To solve them effectively, we propose a dynamicprogramming (DP) based greedy algorithm which is with nearoptimal performance guarantee. The DPbased greedy algorithm, however, is not very efficient due to the expensive marginal gain evaluation. To further speed up the algorithm, we propose an approximate greedy algorithm with linear time complexity w.r.t. the graph size and also with nearoptimal performance guarantee. The approximate greedy algorithm is based on carefully designed random walk sampling and samplematerialization techniques. Extensive experiments demonstrate the effectiveness, efficiency and scalability of the proposed algorithms. I.