Amortized efficiency of list update and paging rules
Communications of the ACM
Walking an unknown street with bounded detour
Computational Geometry: Theory and Applications
Piecemeal learning of an unknown environment
COLT '93 Proceedings of the sixth annual conference on Computational learning theory
Information and Computation
Competitive searching in a generalized street
SCG '94 Proceedings of the tenth annual symposium on Computational geometry
Parallel searching in the plane
Computational Geometry: Theory and Applications
Searching for the kernel of a polygon—a competitive strategy
Proceedings of the eleventh annual symposium on Computational geometry
On-line search in a simple polygon
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Going Home Through an Unknown Street
WADS '95 Proceedings of the 4th International Workshop on Algorithms and Data Structures
ICALP '89 Proceedings of the 16th International Colloquium on Automata, Languages and Programming
Competitive Searching in Polygons - Beyond Generalised Streets
ISAAC '95 Proceedings of the 6th International Symposium on Algorithms and Computation
ESA '96 Proceedings of the Fourth Annual European Symposium on Algorithms
Lower Bounds in On-Line Geometric Searching
FCT '97 Proceedings of the 11th International Symposium on Fundamentals of Computation Theory
Efficient Strategies for Robot Navigation in Unknown Environment
ICALP '94 Proceedings of the 21st International Colloquium on Automata, Languages and Programming
On-line target searching in bounded and unbounded domains
On-line target searching in bounded and unbounded domains
Online Parallel Heuristics and Robot Searching under the Competitive Framework
SWAT '02 Proceedings of the 8th Scandinavian Workshop on Algorithm Theory
Theoretical Computer Science
Online searching with turn cost
Theoretical Computer Science - Approximation and online algorithms
On the optimality of spiral search
SODA '10 Proceedings of the twenty-first annual ACM-SIAM symposium on Discrete Algorithms
| Hi-index | 0.00 |
We investigate parallel searching on m concurrent rays. We assume that a target t is located somewhere on one of the rays; we are given a group of m point robots each of which has to reach t. Furthermore, we assume that the robots have no way of communicating over distance. Given a strategy S we are interested in the competitive ratio defined as the ratio of the time needed by the robots to reach t using S and the time needed to reach t if the location of t is known in advance. If a lower bound on the distance to the target is known, then there is a simple strategy which achieves a competitive ratio of 9--independent of m. We show that 9 is a lower bound on the competitive ratio for two large classes of strategies if m ≥ 2. If the minimum distance to the target is not known in advance, we show a lower bound on the competitive ratio of 1 + 2(k + 1)k+1/kk where k = ⌈logm⌉. We also give a strategy that obtains this ratio.