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Hardness and approximation of gathering in static radio networks
 Parallel Processing Letters
, 2006
"... In this paper, we address the problem of gathering information in a specific node (or sink) of a radio network, where interference constraints are present. We take into account the fact that, when a node transmits, it produces interference in an area bigger than the area in which its message can act ..."
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Cited by 36 (10 self)
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In this paper, we address the problem of gathering information in a specific node (or sink) of a radio network, where interference constraints are present. We take into account the fact that, when a node transmits, it produces interference in an area bigger than the area in which its message can actually be received. The network is modeled by a graph; a node is able to transmit one unit of information to the set of vertices at distance at most dT in the graph, but when doing so it generates interference that does not allow nodes at distance up to dI (dI ≥ dT) to listen to other transmissions. Time is synchronous and divided into timesteps in each of which a round (set of noninterfering radio transmissions) is performed. We give general lower bounds on the number of rounds required to gather into a sink of a general graph, and present an algorithm working on any graph, with an approximation factor of 4. We also show that the problem of finding an optimal strategy for gathering is NPhard, for any values of dI and dT. If dI> dT, we show that the problem remains hard when restricted to the uniform case where each vertex in the network has exactly one piece of information to communicate to the sink. 1
An approximation algorithm for the wireless gathering problem
 In Proc. 10th Scandinavian Workshop on Algorithm Theory
, 2006
"... Abstract. The Wireless Gathering Problem is to find a schedule for data gathering in a wireless static network. The problem is to gather a set of messages from the nodes in the network at which they originate to a central node, representing a powerful base station. The objective is to minimize the t ..."
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Cited by 28 (3 self)
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Abstract. The Wireless Gathering Problem is to find a schedule for data gathering in a wireless static network. The problem is to gather a set of messages from the nodes in the network at which they originate to a central node, representing a powerful base station. The objective is to minimize the time to gather all messages. The sending pattern or schedule should avoid interference of radio signals, which distinguishes the problem from wired networks. We study the Wireless Gathering Problem from a combinatorial optimization point of view in a centralized setting. This problem is known to be NPhard when messages have no release time. We consider the more general case in which messages may be released over time. For this problem we present a polynomialtime online algorithm which gives a 4approximation. We also show that within the class of shortest path following algorithms no algorithm can have approximation ratio better than 4. We also formulate some challenging open problems concerning complexity and approximability for variations of the problem. 1
Contents lists available at ScienceDirect
"... Information Sciences journal homepage: www.elsevier.com/locate/ins Management of evolving semantic grid metadata ..."
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Information Sciences journal homepage: www.elsevier.com/locate/ins Management of evolving semantic grid metadata
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, 2010
"... HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte p ..."
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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et a ̀ la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
6.1.1. Open ComponentBased Architecture For DiscreteEvent Simulation 5
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