CZYZOWICZ, Jurek; DERENIOWSKI, Dariusz; GASIENIEC, Leszek; KLASING, Ralf; KOSOWSKI, Adrian; PAJAK, Dominik

doi:10.1007/978-3-642-54423-1_30

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CZYZOWICZ, Jurek
Département d'Informatique et d'Ingénierie [DII]

DERENIOWSKI, Dariusz
Department of Algorithms and Systems Modelling [ETI GUT] [Gdansk University of Technology]

GASIENIEC, Leszek
Department of Computer Science [Liverpool]

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Communication dans un congrès

Ce document a été publié dans

LATIN - 11th Latin American Theoretical INformatics Symposium, 2014-03-31, Montevideo. 2014-03-31, vol. 8392, p. 342-354

Springer

Résumé en anglais

A set of mobile agents is placed at different nodes of a $n$-node network. The agents synchronously move along the network edges in a {\em collision-free} way, i.e., in no round may two agents occupy the same node. In each round, an agent may choose to stay at its currently occupied node or to move to one of its neighbors. An agent has no knowledge of the number and initial positions of other agents. We are looking for the shortest possible time required to complete the collision-free {\em network exploration}, i.e., to reach a configuration in which each agent is guaranteed to have visited all network nodes and has returned to its starting location. We first consider the scenario when each mobile agent knows the map of the network, as well as its own initial position. We establish a connection between the number of rounds required for collision-free exploration and the degree of the minimum-degree spanning tree of the graph. We provide tight (up to a constant factor) lower and upper bounds on the collision-free exploration time in general graphs, and the exact value of this parameter for trees. For our second scenario, in which the network is unknown to the agents, we propose collision-free exploration strategies running in $O(n^2)$ rounds for tree networks and in $O(n^5\log n)$ rounds for general networks.< Réduire