APPROX '02 Proceedings of the 5th International Workshop on Approximation Algorithms for Combinatorial Optimization
Algorithms for the on-line quota traveling salesman problem
Information Processing Letters
Theoretical Computer Science - Approximation and online algorithms
Topology matters: smoothed competitiveness of metrical task systems
Theoretical Computer Science
Online Routing Problems: Value of Advanced Information as Improved Competitive Ratios
Transportation Science
The on-line asymmetric traveling salesman problem
Journal of Discrete Algorithms
On the power of lookahead in on-line server routing problems
Theoretical Computer Science
AAIM '09 Proceedings of the 5th International Conference on Algorithmic Aspects in Information and Management
On minimizing the maximum flow time in the online dial-a-ride problem
WAOA'05 Proceedings of the Third international conference on Approximation and Online Algorithms
On the power of lookahead in on-line vehicle routing problems
COCOON'05 Proceedings of the 11th annual international conference on Computing and Combinatorics
On-Line algorithms, real time, the virtue of laziness, and the power of clairvoyance
TAMC'06 Proceedings of the Third international conference on Theory and Applications of Models of Computation
The on-line asymmetric traveling salesman problem
WADS'05 Proceedings of the 9th international conference on Algorithms and Data Structures
Online k-server routing problems
WAOA'06 Proceedings of the 4th international conference on Approximation and Online Algorithms
Competitive analysis of a dispatch policy for a dynamic multi-period routing problem
Operations Research Letters
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In the online traveling salesman problem, requests for visits to cities (points in a metric space) arrive online while the salesman is traveling. The salesman moves at no more than unit speed and starts and ends his work at a designated origin. The objective is to find a routing for the salesman that finishes as early as possible.Performance of algorithms is measured through their competitive ratio, comparing the outcome of the algorithms with that of an adversary who provides the problem instance and therefore is able to achieve the optimal offline solution. Objections against such omnipotent adversaries have lead us to devise an adversary that is in a natural way, in the context of routing problems, more restricted in power.For the exposition we consider the online traveling salesman problem on the metric space given by , the non-negative part of the real line. We show that a very natural strategy is 3/2-competitive against the conventional adversary, which matches the lower-bound on competitive ratios achievable for algorithms for this problem.Against the more"fair adversary", that we propose, we show that there exists an algorithm with competitive ratioand provide a matching lower bound.We also show competitiveness results for a special class of algorithms (calledzealous algorithms) that do not allow waiting time for the server as long as there are requests unserved.