Searching for a black hole in arbitrary networks: optimal mobile agent protocols
Proceedings of the twenty-first annual symposium on Principles of distributed computing
Mobile Search for a Black Hole in an Anonymous Ring
DISC '01 Proceedings of the 15th International Conference on Distributed Computing
Time Limited Blackbox Security: Protecting Mobile Agents From Malicious Hosts
Mobile Agents and Security
Protecting Mobile Agents Against Malicious Hosts
Mobile Agents and Security
A Framework to Protect Mobile Agents by Using Reference States
ICDCS '00 Proceedings of the The 20th International Conference on Distributed Computing Systems ( ICDCS 2000)
Complexity of Searching for a Black Hole
Fundamenta Informaticae
Searching for black-hole faults in a network using multiple agents
OPODIS'06 Proceedings of the 10th international conference on Principles of Distributed Systems
Distributed security algorithms by mobile agents
ICDCN'06 Proceedings of the 8th international conference on Distributed Computing and Networking
Black hole search in asynchronous rings using tokens
CIAC'06 Proceedings of the 6th Italian conference on Algorithms and Complexity
Searching for a black hole in tree networks
OPODIS'04 Proceedings of the 8th international conference on Principles of Distributed Systems
Hardness and approximation results for black hole search in arbitrary graphs
SIROCCO'05 Proceedings of the 12th international conference on Structural Information and Communication Complexity
Approximation bounds for black hole search problems
OPODIS'05 Proceedings of the 9th international conference on Principles of Distributed Systems
Synchronization Helps Robots to Detect Black Holes in Directed Graphs
OPODIS '09 Proceedings of the 13th International Conference on Principles of Distributed Systems
FUN'12 Proceedings of the 6th international conference on Fun with Algorithms
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We consider a fixed, undirected, known network and a number of "mobile agents" which can traverse the network in synchronized steps. Some nodes in the network may be faulty and the agents are to find the faults and repair them. The agents could be software agents, if the underlying network represents a computer network, or robots, if the underlying network represents some potentially hazardous physical terrain. Assuming that the first agent encountering a faulty node can immediately repair it, it is easy to see that the number of steps necessary and sufficient to complete this task is 茂戮驴(n/k+ D), where nis the number of nodes in the network, Dis the diameter of the network, and kis the number of agents. We consider the case where one agent can repair only one faulty node. After repairing the fault, the agent dies. We show that a simple deterministic algorithm for this problem terminates within O(n/k+ Dlogf/loglogf) steps, where f= min {n/k, n/D}, assuming that the number of faulty nodes is at most k/2. We also demonstrate the worst-case asymptotic optimality of this algorithm by showing a network such that for any deterministic algorithm, there is a placement of k/2 faults forcing the algorithm to work for 茂戮驴(n/k+ Dlogf/loglogf) steps.