On the competitive ratio of the work function algorithm for the k-server problem

The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric space with minimum total mileage. The k-server conjecture of Manasse, McGeogh, and Sleator states that there exists a k-competitive online algori...

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Veröffentlicht in:Theoretical computer science Jg. 324; H. 2; S. 337 - 345
Hauptverfasser: Bartal, Yair, Koutsoupias, Elias
Format: Journal Article
Sprache:Englisch
Veröffentlicht: Amsterdam Elsevier B.V 20.09.2004
Elsevier
Schlagworte:
Algorithmics. Computability. Computer arithmetics
Applied sciences
Computer science; control theory; systems
Exact sciences and technology
Online algorithms
The k-server problem
Theoretical computing
Work function
Online algorithms
Work function
The k-server problem
Online algorithm
Metric space
Computer theory
k server problem
Competitive algorithms
ISSN:0304-3975, 1879-2294
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Abstract The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric space with minimum total mileage. The k-server conjecture of Manasse, McGeogh, and Sleator states that there exists a k-competitive online algorithm. The conjecture has been open for over 15 years. The top candidate online algorithm for settling this conjecture is the work function algorithm ( WFA) which was shown to have competitive ratio at most 2 k−1. In this paper, we lend support to the conjecture that WFA is in fact k-competitive by proving that it achieves this ratio in several special metric spaces: the line, the star, and all metric spaces with k+2 points.
AbstractList The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric space with minimum total mileage. The k-server conjecture of Manasse, McGeogh, and Sleator states that there exists a k-competitive online algorithm. The conjecture has been open for over 15 years. The top candidate online algorithm for settling this conjecture is the work function algorithm (WFA) which was shown to have competitive ratio at most 2k-1. In this paper, we lend support to the conjecture that WFA is in fact k-competitive by proving that it achieves this ratio in several special metric spaces: the line, the star, and all metric spaces with k+2 points.
The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric space with minimum total mileage. The k-server conjecture of Manasse, McGeogh, and Sleator states that there exists a k-competitive online algorithm. The conjecture has been open for over 15 years. The top candidate online algorithm for settling this conjecture is the work function algorithm ( WFA) which was shown to have competitive ratio at most 2 k−1. In this paper, we lend support to the conjecture that WFA is in fact k-competitive by proving that it achieves this ratio in several special metric spaces: the line, the star, and all metric spaces with k+2 points.
Author Bartal, Yair
Koutsoupias, Elias
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  givenname: Elias
  surname: Koutsoupias
  fullname: Koutsoupias, Elias
  email: elias@di.uoa.gr
  organization: Department of Informatics, University of Athens, Athens, Greece and Computer Science Department, University of California, Los Angeles, USA
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10.1145/331605.331606
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10.1016/0020-0190(96)00010-5
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Issue 2
Keywords Online algorithms
Work function
The k-server problem
Online algorithm
Metric space
Computer theory
k server problem
Competitive algorithms
Language English
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Snippet The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric...
The k-server problem is one of the most fundamental online problems. The problem is to schedule k mobile servers to visit a sequence of points in a metric...
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SubjectTerms Algorithmics. Computability. Computer arithmetics
Applied sciences
Computer science; control theory; systems
Exact sciences and technology
Online algorithms
The k-server problem
Theoretical computing
Work function
Title On the competitive ratio of the work function algorithm for the k-server problem
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