Exploring Unknown Environments
SIAM Journal on Computing
The power of a pebble: exploring and mapping directed graphs
Information and Computation
Optimal graph exploration without good maps
Theoretical Computer Science
Spray and wait: an efficient routing scheme for intermittently connected mobile networks
Proceedings of the 2005 ACM SIGCOMM workshop on Delay-tolerant networking
Study of a bus-based disruption-tolerant network: mobility modeling and impact on routing
Proceedings of the 13th annual ACM international conference on Mobile computing and networking
Journal of Graph Theory
Label-guided graph exploration by a finite automaton
ACM Transactions on Algorithms (TALG)
How to Explore a Fast-Changing World (Cover Time of a Simple Random Walk on Evolving Graphs)
ICALP '08 Proceedings of the 35th international colloquium on Automata, Languages and Programming, Part I
Scalable Routing in Cyclic Mobile Networks
IEEE Transactions on Parallel and Distributed Systems
Mapping an unfriendly subway system
FUN'10 Proceedings of the 5th international conference on Fun with algorithms
Routing in carrier-based mobile networks
SIROCCO'11 Proceedings of the 18th international conference on Structural information and communication complexity
Time-varying graphs and dynamic networks
ADHOC-NOW'11 Proceedings of the 10th international conference on Ad-hoc, mobile, and wireless networks
On the power of waiting when exploring public transportation systems
OPODIS'11 Proceedings of the 15th international conference on Principles of Distributed Systems
FUN'12 Proceedings of the 6th international conference on Fun with Algorithms
Brief announcement: mobile agent rendezvous on edge evolving rings
SSS'12 Proceedings of the 14th international conference on Stabilization, Safety, and Security of Distributed Systems
On the exploration of time-varying networks
Theoretical Computer Science
Efficient routing in carrier-based mobile networks
Theoretical Computer Science
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We study the computability and complexity of the exploration problem in a class of highly dynamic graphs: periodically varying (PV) graphs, where the edges exist only at some (unknown) times defined by the periodic movements of carriers. These graphs naturally model highly dynamic infrastructure-less networks such as public transports with fixed timetables, low earth orbiting (LEO) satellite systems, security guards' tours, etc. We establish necessary conditions for the problem to be solved. We also derive lower bounds on the amount of time required in general, as well as for the PV graphs defined by restricted classes of carriers movements: simple routes, and circular routes. We then prove that the limitations on computability and complexity we have established are indeed tight. We do so constructively presenting two worst case optimal solution algorithms, one for anonymous systems, and one for those with distinct nodes ids.