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Aging analysis in largescale wireless sensor networks
 Ad Hoc Networks
, 2008
"... Most research on the lifetime of wireless sensor networks has focused primarily on the energy depletion of the very first node. In this study, we analyze the entire aging process of the sensor network in a periodic data gathering application. In sparse node deployments, it is observed that the exist ..."
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Most research on the lifetime of wireless sensor networks has focused primarily on the energy depletion of the very first node. In this study, we analyze the entire aging process of the sensor network in a periodic data gathering application. In sparse node deployments, it is observed that the existence of multiple alternate paths to a sink leads to a power law relation between connectivity to a sink and hop levels, where the probability of connection to a sink decreases in proportion to the hop level with an exponent, when device failures occur over time. Then, we provide distancelevel analysis for the dense deployment case by taking into account the reconstruction of a data gathering tree and workload shift caused by the energy depletion of nodes with larger workload. Extensive simulation results obtained with a realistic wireless link model are compared to our analytical results. Finally, we show through an analysis of the aging of firsthop nodes that increasing node density with a fixed radio range does not affect the network disconnection time.
E.G.: Optimal sensor network layout using multiobjective metaheuristics
 J. of Universal Computer Science
, 2008
"... Abstract: Wireless Sensor Networks (WSN) allow, thanks to the use of small wireless devices known as sensor nodes, the monitorization of wide and remote areas with precision and liveness unseen to the date without the intervention of a human operator. For many WSN applications it is fundamental to a ..."
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Abstract: Wireless Sensor Networks (WSN) allow, thanks to the use of small wireless devices known as sensor nodes, the monitorization of wide and remote areas with precision and liveness unseen to the date without the intervention of a human operator. For many WSN applications it is fundamental to achieve full coverage of the terrain monitored, known as sensor field. The next major concerns are the energetic efficiency of the network, in order to increase its lifetime, and having the minimum possible number of sensor nodes, in order to reduce the network cost. The task of placing the sensor nodes while addressing these objectives is known as WSN layout problem. In this paper we address a WSN layout problem instance in which full coverage is treated as a constraint while the other two objectives are optimized using a multiobjective approach. We employ a set of multiobjective optimization algorithms for this problem where we define the energy efficiency and the number of nodes as the independent optimization objectives. Our results prove the efficiency of multiobjective metaheuristics to solve this kind of problem and encourage further research on more realistic instances and more constrained scenarios. Key Words: sensor networks, multiobjective optimization, metaheuristics Category: G.1.6, I.2.8.
Optimal Placement and Channel Assignment of Relay Stations in Heterogeneous Wireless Mesh Networks by Modified Bender’s Decomposition
"... Fixed Broadband Wireless Access (FBWA) technology is designed to serve as a wireless DSL replacement to provide broadband Internet access in underserved areas where no other access technology exists. Due to the enormousness of the target service area, relay equipment play an important role in such n ..."
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Fixed Broadband Wireless Access (FBWA) technology is designed to serve as a wireless DSL replacement to provide broadband Internet access in underserved areas where no other access technology exists. Due to the enormousness of the target service area, relay equipment play an important role in such networks, and the installation and maintenance cost of the network is directly proportional to the cost of the relay equipment. To minimize the network operational cost, an optimization framework which computes the minimum number of relay stations and their corresponding placements and channel assignments in the network is desired. Because the problem is NPhard, we propose an efficient optimization algorithm based on a modified version of Bender’s decomposition to iteratively compute converging bounds to the problem solution. Our numerical results show that by using a few relay stations in a rural community, broadband Internet access can be established in a cost effective manner. Key words: Fixed broadband wireless access, relay stations, placement and channel assignment, Bender’s decomposition, mathematical programming/optimization.
Optimal Placement of Relay infrastructure in Heterogeneous Wireless Mesh Networks by Bender’s Decomposition
 In Proc. QShine’06
, 2006
"... designed to serve as a wireless DSL replacement technology to provide broadband access in underserved areas where no other access technology exists. Due to the enormousness of the target service area, relay equipment play an important role in such networks, and the installation and maintenance cost ..."
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Cited by 1 (0 self)
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designed to serve as a wireless DSL replacement technology to provide broadband access in underserved areas where no other access technology exists. Due to the enormousness of the target service area, relay equipment play an important role in such networks, and the installation and maintenance cost of the network is directly proportional to the cost of the relay equipment. To minimize the network operational cost, we develop an optimization framework which computes the minimum number of relay stations and their placement in the network such that the demands from the end users are met. 1.
Sensor Deployment Algorithms for Target Positioning Services
, 2007
"... From either practical or theoretical viewpoint, wireless sensor network (WSN) techniques are new and important research issues. Numbers of interesting applications for WSNs have been investigated, e.g., surveillance, target positioning, tracing, and health care. Sensor networks have been forecasted ..."
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From either practical or theoretical viewpoint, wireless sensor network (WSN) techniques are new and important research issues. Numbers of interesting applications for WSNs have been investigated, e.g., surveillance, target positioning, tracing, and health care. Sensor networks have been forecasted to apply variously, both the civilian and military domains.
Modelling and Solving Optimal Placement problems in Wireless Sensor Networks
"... In this work, the optimal sensor displacement problem in wireless sensor networks is addressed. It is assumed that a network, consisting of independent, collaborative and mobile nodes, is available. Starting from an initial configuration, the aim is to define a specific sensors displacement, which a ..."
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In this work, the optimal sensor displacement problem in wireless sensor networks is addressed. It is assumed that a network, consisting of independent, collaborative and mobile nodes, is available. Starting from an initial configuration, the aim is to define a specific sensors displacement, which allows the network to achieve high performance, in terms of energy consumption and travelled distance. To mathematically represent the problem under study, different innovative optimization models are proposed and defined, by taking into account different performance objectives. An extensive computational phase is carried out in order to assess the behaviour of the developed models in terms of solution quality and computational effort. A comparison with distributed approaches is also given, by considering different scenarios. Keywords:
A Framework for Modeling the Lifetime and Residual Energy Distribution in Wireless Networks
"... A number of important characteristics of wireless sensor networks such as the lifetime, connectivity and coverage are determined the residual power levels of the nodes in the network. This paper presents a general framework for modeling the availability of power at sensor nodes as a function of time ..."
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A number of important characteristics of wireless sensor networks such as the lifetime, connectivity and coverage are determined the residual power levels of the nodes in the network. This paper presents a general framework for modeling the availability of power at sensor nodes as a function of time. Models are developed for sensors with and without battery recharging and expressions are derived for the network lifetime as well as the distribution and moments of random variables describing the number of sensors with different levels of residual energy as a function of time. Finally, the effect of the packet arrival rates and a sensor’s geographical location are modeled.
www.elsevier.com/locate/jpdc Energy optimal data propagation in wireless sensor networks �
"... We propose an algorithm to compute the optimal parameters of a probabilistic data propagation algorithm for wireless sensor networks (WSN). The probabilistic data propagation algorithm we consider was introduced in previous work, and it is known that this algorithm, when used with adequate parameter ..."
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We propose an algorithm to compute the optimal parameters of a probabilistic data propagation algorithm for wireless sensor networks (WSN). The probabilistic data propagation algorithm we consider was introduced in previous work, and it is known that this algorithm, when used with adequate parameters, balances the energy consumption and increases the lifespan of the WSN. However, we show that in the general case achieving energy balance may not be possible. We propose a centralized algorithm to compute the optimal parameters of the probabilistic data propagation algorithm, and prove that these parameters maximize the lifespan of the network even when it is not possible to achieve energy balance. Compared to previous work, our contribution is the following: (a) we give a formal definition of an optimal data propagation algorithm: an algorithm maximizing the lifespan of the network. (b) We find a simple necessary and sufficient condition for the data propagation algorithm to be optimal. (c) We constructively prove that there exists a choice of parameters optimizing the probabilistic data propagation algorithm. (d) We provide a centralized algorithm to compute these optimal parameters, thus enabling their use in a WSN. (e) We extend previous work by considering the energy consumption per sensor, instead of the consumption per slice, and propose a spreading technique to balance the energy among sensors of a same slice. The technique is numerically validated by simulating a WSN accomplishing a data monitoring task and propagating data using the probabilistic data propagation algorithm with optimal parameters.