A new competitive algorithm for agent searching in unknown streets
In this paper we present a simple on-line strategy based on a continuous angle bisector approach for searching an unknown street polygon. The proposed strategy achieves a competitive ratio of 1+loge(1+ cos α/2)+δ, where 0≤α≤π, and δ is a given constant greater than zero. By choosing an arbitrarily small value for δ, the value of this ratio is 1.7, which is significantly better than the previous upperbound of 2.83 (derived by Kleinberg ), considering that the lowerbound for this problem is √2(> 1.41) (derived by Klein ).
Unable to display preview. Download preview PDF.
- 1.Baeza-Yates, R. A., J.C. Culberson, and G.J.E.Rawlins. Searching in the plane. Information and Computation 106 (1993), 234–252.Google Scholar
- 2.Blum, A., P.Raghavan, and B.Schieber. Navigating in unfamiliar geometric terrains. In STOC (1991), pp. 494–504.Google Scholar
- 3.Dasgupta, P., P.P. Chakrabarti, and S.C. DeSarkar. Agent searching in a tree and the optimality of iterative deepening. Artificial Intelligence 71 (1994), 195–208.Google Scholar
- 4.Icking, C., and R.Klein. Searching for the kernel of a polygon: A competitive strategy. In Proc. of the 11thComputational Geometry Conference (1995), pp. 258–266.Google Scholar
- 5.Klein, R. Walking an unknown street with bounded detour. Computational Geometry: Theory and Applications 1 (1992), 325–351.Google Scholar
- 6.Kleinberg, J. M. On-line search in a simple polygon. In Proc. of SODA '94 (1994), pp. 8–15.Google Scholar
- 7.Papadimitriou, C. H., and M.Yannakakis. Shortest paths without a map. Theoretical Computer Science 84 (1991), 127–150.Google Scholar