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 in an unknown environment: an optimal randomized algorithm for the cow-path problem
SODA '93 Proceedings of the fourth annual ACM-SIAM Symposium on Discrete algorithms
On-line search in a simple polygon
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Optimal constructions of hybrid algorithms
SODA '94 Proceedings of the fifth annual ACM-SIAM symposium on Discrete algorithms
Lower bounds in on-line geometric searching
Computational Geometry: Theory and Applications
The ultimate strategy to search on m rays?
Theoretical Computer Science
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
Efficient Strategies for Robot Navigation in Unknown Environment
ICALP '94 Proceedings of the 21st International Colloquium on Automata, Languages and Programming
Teaching, learning and exploration
Teaching, learning and exploration
On-line target searching in bounded and unbounded domains
On-line target searching in bounded and unbounded domains
STACS'99 Proceedings of the 16th annual conference on Theoretical aspects of computer science
Graph exploration by a finite automaton
Theoretical Computer Science - Mathematical foundations of computer science 2004
Ranking hypotheses to minimize the search cost in probabilistic inference models
Discrete Applied Mathematics
Introduction to the SIGACT news online algorithms column
ACM SIGACT News
On Developing New Models, with Paging as a Case Study
ACM SIGACT News
On the optimality of spiral search
SODA '10 Proceedings of the twenty-first annual ACM-SIAM symposium on Discrete Algorithms
Multi-target ray searching problems
WADS'11 Proceedings of the 12th international conference on Algorithms and data structures
Survey: Online algorithms for searching and exploration in the plane
Computer Science Review
| Hi-index | 5.23 |
In this paper we investigate parallel searches on m concurrent rays for a point target t located at some unknown distance along one of the rays. A group of p agents or robots moving at unit speed searches for t. The search succeeds when an agent reaches the point t. Given a strategy S the competitive ratio is the ratio of the time needed by the agents to find t using S and the time needed if the location of t had been known in advance. We provide a strategy with competitive ratio of 1 + 2(m/p - 1)(m/(m - p))m/p and prove that this is optimal. This problem has applications in multiple heuristic searches in AI as well as robot motion planning. The case p = 1 is known in the literature as the cow path problem.