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The antibandwidth problem is to label vertices of graph G(V, E) bijectively by integers 0, 1, ..., |V | − 1 in such a way that the minimal difference of labels of adjacent vertices is maximised. In this paper we study the antibandwidth of Hamming graphs. We provide labeling algorithms and tight upper bounds for general Hamming graphs Π d k=1 K n k. We have(More)
In this paper we address the problem of mobile agents searching for a highly harmful item (called a black hole) in a ring network. The black hole is a stationary process that destroys visiting agents upon their arrival without leaving any observable trace of such a destruction. The task is to have at least one surviving agent able to unambiguously report(More)
Mobile agents operating in networked environments face threats from other agents as well as from the hosts (i.e., network sites) they visit. A black hole is a harmful host that destroys incoming agents without leaving any trace. To determine the location of such a harmful host is a dangerous but crucial task, called black hole search. The most important(More)
We consider the problem of cooperative network exploration by agents under the assumption that there is a harmful host present in the network that destroys the incoming agents without outside trace – the so-called black hole search problem. Many variants of this problem have been studied, with various assumptions about the timing, agents' knowledge about(More)
Many protocols in distributed computing make use of dominating and connected dominating sets, for example for broadcasting and the computation of routing. Ad hoc networks impose an additional requirement that algorithms for the construction of such sets should be local in the sense that each node of the network should make decisions based only on the(More)
We consider the problem of perpetual traversal by a single agent in an anonymous undirected graph G. Our requirements are: (1) deterministic algorithm, (2) each node is visited within O(n) moves, (3) the agent uses no memory, it can use only the label of the link via which it arrived to the current node, (4) no marking of the underlying graph is allowed and(More)
We consider several variations of the problems of covering a set of barriers using sensors so that sensors can detect any intruder crossing any of the barriers. Sensors are initially located in the plane and they can relocate to the barriers. We assume that each sensor can detect any intruder in a circular area centered at the sensor. Given a set of(More)
Almost all the vast literature on graph exploration assumes that the graph is static: its topology does not change during the exploration, except for occasional faults. To date, very little is known on exploration of dynamic graphs, where the topology is continously changing. The few studies have been limited to the centralized (or post-mortem) case,(More)