Amortized efficiency of list update and paging rules
Communications of the ACM
Navigating in unfamiliar geometric terrain
STOC '91 Proceedings of the twenty-third annual ACM symposium on Theory of computing
Theoretical Computer Science
Walking an unknown street with bounded detour
Computational Geometry: Theory and Applications
Information and Computation
On-line search in a simple polygon
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Searching for the kernel of a polygon—a competitive strategy
Proceedings of the eleventh annual symposium on Computational geometry
New competitive strategies for searching in unknown star-shaped polygons
SCG '97 Proceedings of the thirteenth annual symposium on Computational geometry
Position-independent near optimal searching and on-line recognition in star polygons
SCG '97 Proceedings of the thirteenth annual symposium on Computational geometry
Localizing a robot with minimum travel
Proceedings of the sixth annual ACM-SIAM symposium on Discrete algorithms
A competitive strategy for learning a polygon
SODA '97 Proceedings of the eighth annual ACM-SIAM symposium on Discrete algorithms
Exploring an Unknown Polygonal Environment with Bounded Visibility
ICCS '01 Proceedings of the International Conference on Computational Sciences-Part I
Online Parallel Heuristics and Robot Searching under the Competitive Framework
SWAT '02 Proceedings of the 8th Scandinavian Workshop on Algorithm Theory
Position-Independent Street Searching
WADS '99 Proceedings of the 6th International Workshop on Algorithms and Data Structures
Searching Rectilinear Streets Completely
WADS '99 Proceedings of the 6th International Workshop on Algorithms and Data Structures
The Ultimate Strategy to Search on m Rays?
COCOON '98 Proceedings of the 4th Annual International Conference on Computing and Combinatorics
On the Competitive Complexity of Navigation Tasks
Revised Papers from the International Workshop on Sensor Based Intelligent Robots
A lower bound for randomized searching on m rays
Computer Science in Perspective
Searching and on-line recognition of star-shaped polygons
Information and Computation
Theoretical Computer Science
On-line path planning in an unknown polygonal environment
Information Sciences—Informatics and Computer Science: An International Journal
An optimal strategy for searching in unknown streets
STACS'99 Proceedings of the 16th annual conference on Theoretical aspects of computer science
STACS'99 Proceedings of the 16th annual conference on Theoretical aspects of computer science
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We consider the problem of a robot which has to find a path in an unknown simple polygon from one point s to another point t, based only on what it has seen so far. A Street is a polygon for which the two boundary chains from s to t are mutually weakly visible, and the set of streets was the only class of polygons for which a competitive search algorithm was known.We define a new, strictly larger class of polygons, called generalized streets or G -streets which are characterized by the property that every point on the boundary of a G -street is visible from a point on a horizontal line segment connecting the two boundary chains from s to t. We present an on-line strategy for a robot placed at s to find t in an unknown rectilinear G -street; the length of the path created is at most 9 times the length of the shortest path in the L1 metric. This is optimal since we show that no strategy can achieve a smaller competitive factor for all rectilinear G -streets. Compared to the L2-shortest path, the strategy is 9.06-competitive which leaves only a very small gap to the lower bound of 9.