A heuristic with worst-case analysis for minimax routing of two travelling salesmen on a tree
Discrete Applied Mathematics
Exploring unknown undirected graphs
Journal of Algorithms
The power of a pebble: exploring and mapping directed graphs
Information and Computation
Graph exploration by a finite automaton
Theoretical Computer Science - Mathematical foundations of computer science 2004
Networks
Searching for a Black Hole in Synchronous Tree Networks¶
Combinatorics, Probability and Computing
Mobile Search for a Black Hole in an Anonymous Ring
Algorithmica
Hardness and approximation results for Black Hole Search in arbitrary networks
Theoretical Computer Science
Map construction of unknown graphs by multiple agents
Theoretical Computer Science
Journal of Graph Theory
Map construction and exploration by mobile agents scattered in a dangerous network
IPDPS '09 Proceedings of the 2009 IEEE International Symposium on Parallel&Distributed Processing
Black Hole Search with Tokens in Interconnected Networks
SSS '09 Proceedings of the 11th International Symposium on Stabilization, Safety, and Security of Distributed Systems
Locating a Black Hole without the Knowledge of Incoming Link
Algorithmic Aspects of Wireless Sensor Networks
Synchronous black hole search in directed graphs
Theoretical Computer Science
Tight bounds for scattered black hole search in a ring
SIROCCO'11 Proceedings of the 18th international conference on Structural information and communication complexity
Improving the optimal bounds for black hole search in rings
SIROCCO'11 Proceedings of the 18th international conference on Structural information and communication complexity
Black hole search with finite automata scattered in a synchronous torus
DISC'11 Proceedings of the 25th international conference on Distributed computing
Searching for black-hole faults in a network using multiple agents
OPODIS'06 Proceedings of the 10th international conference on Principles of Distributed Systems
Black hole search in asynchronous rings using tokens
CIAC'06 Proceedings of the 6th Italian conference on Algorithms and Complexity
Black hole search in directed graphs
SIROCCO'09 Proceedings of the 16th international conference on Structural Information and Communication Complexity
Periodic data retrieval problem in rings containing a malicious host
SIROCCO'10 Proceedings of the 17th international conference on Structural Information and Communication Complexity
Complexity of Searching for a Black Hole
Fundamenta Informaticae
Searching for a black hole in interconnected networks using mobile agents and tokens
Journal of Parallel and Distributed Computing
Hi-index | 5.23 |
Consider a team of (one or more) mobile agents operating in a graph G. Unaware of the graph topology and starting from the same node, the team must explore the graph. This problem, known as graph exploration, was initially formulated by Shannon in 1951, and has been extensively studied since under a variety of conditions. Most of the existing investigations have assumed that the network is safe for the agents, and the vast majority of the solutions presented in the literature succeed in their task only under this assumption. Recently, the exploration problem has been examined also when the network is unsafe. The danger examined is the presence in the network of a black hole, a node that disposes of any incoming agent without leaving any observable trace of this destruction. The goal is for at least one agent to survive and to have all the surviving agents to construct a map of the network, indicating the edges leading to the black hole. This variant of the problem is also known as a black hole search. This problem has been investigated for the most part assuming powerful inter-agent communication mechanisms: whiteboards at all nodes. Indeed, in this model, the black hole search problem can be solved with an optimal team size and performing a polynomial number of moves. In this paper, we consider the less powerful enhanced token model: each agent has available a token that can be carried, placed on a node or on a link, and can be removed from it. All tokens are identical and no other form of marking or communication is available. We constructively prove that the black hole search problem can be solved also in this model; furthermore, this can be done using a team of agents of optimal size and performing a polynomial number of moves. Our algorithm works even if the agents are asynchronous and if both the agents and the nodes are anonymous.