Polylogarithmic-overhead piecemeal graph exploration

We introduce a new traversal technique in the coxltext of piecemeal exploration of unknown graphs. The problem of learning a graph via piecemeal exploration requires a robot to create a complete map of its environment, subject to two constraints. First, it cannot jump between non-adjacent vertices in oue time step and second, it must return to a fixed starting point every so often. This paper presents the recursive piecemeal search (RPS) strategy together with an algorithm for the above problem. We are able to achieve O(log’n) overhead (where ‘n is the number of vertices), improving 011 previous results of Awerbuch, Betke, Rive& and Singh which require O(n’) overhead. The graph is discovered via the recursive piecerneal search, which can be viewed as a combination of breadthfirst and depth-first passes. The construction of FLPS trees relies on the concept of sparse neighborhood covers aud captures nicely the nature of the graph exploration problem.

[1]  Avrim Blum,et al.  An Online Algorithm for Improving Performance in Navigation , 2000, SIAM J. Comput..

[2]  Xiaotie Deng,et al.  How to learn an unknown environment , 1991, [1991] Proceedings 32nd Annual Symposium of Foundations of Computer Science.

[3]  S. Sitharama Iyengar,et al.  Robot navigation in unknown terrains: Introductory survey of non-heuristic algorithms , 1993 .

[4]  Lenore Cowen,et al.  Near-linear cost sequential and distributed constructions of sparse neighborhood covers , 1993, Proceedings of 1993 IEEE 34th Annual Foundations of Computer Science.

[5]  Avrim Blum,et al.  An on-line algorithm for improving performance in navigation , 1993, Proceedings of 1993 IEEE 34th Annual Foundations of Computer Science.

[6]  Mihalis Yannakakis,et al.  Shortest Paths Without a Map , 1989, Theor. Comput. Sci..

[7]  Amos Fiat,et al.  Randomized robot navigation algorithms , 1996, SODA '96.

[8]  Xiaotie Deng,et al.  Exploring an unknown graph , 1990, Proceedings [1990] 31st Annual Symposium on Foundations of Computer Science.

[9]  Baruch Schieber,et al.  Navigating in Unfamiliar Geometric Terrain , 1997, SIAM J. Comput..

[10]  Mona Singh,et al.  Piecemeal Graph Exploration by a Mobile Robot , 1999, Inf. Comput..

[11]  Rolf Klein,et al.  A competitive strategy for learning a polygon , 1997, SODA '97.

[12]  Michael A. Bender,et al.  The power of team exploration: two robots can learn unlabeled directed graphs , 1994, Proceedings 35th Annual Symposium on Foundations of Computer Science.

[13]  Ronald L. Rivest,et al.  Introduction to Algorithms , 1990 .

[14]  Mona Singh,et al.  Piecemeal Learning of an Unknown Environment , 1993, COLT.

[15]  Mona Singh,et al.  Piecemeal graph exploration by a mobile robot (extended abstract) , 1995, COLT '95.

[16]  Susanne Albers,et al.  Exploring Unknown Environments , 2000, SIAM J. Comput..

[17]  Amos Fiat,et al.  Online Navigation in a Room , 1992, J. Algorithms.

[18]  Margrit Betke ALGORITHMS FOR EXPLORING AN UNKNOWN GRAPH , 1992 .