Abstract
The weighted k-server problem is a natural generalization of the k-server problem where each server has a different weight. We consider the problem on uniform metrics, which corresponds to a natural generalization of paging. Our main result is a doubly exponential lower bound on the competitive ratio of any deterministic online algorithm, that essentially matches the known upper bounds for the problem and closes a large and long-standing gap. The lower bound is based on relating the weighted k-server problem to a certain combinatorial problem and proving a Ramsey-theoretic lower bound for it. This combinatorial connection also reveals several structural properties of low cost feasible solutions to serve a sequence of requests. We use this to show that the generalized Work Function Algorithm achieves an almost optimum competitive ratio, and to obtain new refined upper bounds on the competitive ratio for the case of d different weight classes.
Original language | English |
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Title of host publication | 2017 IEEE 58th Annual Symposium on Foundations of Computer Science (FOCS), 15-17 October 2017, Berkeley, California |
Place of Publication | Piscataway |
Publisher | Institute of Electrical and Electronics Engineers |
Pages | 493-504 |
Number of pages | 12 |
ISBN (Electronic) | 978-1-5386-3464-6 |
ISBN (Print) | 978-1-5386-3465-3 |
DOIs | |
Publication status | Published - 2017 |
Event | 58th Annual IEEE Symposium on Foundations of Computer Science (FOCS 2017), October 15-17, 2017, Berkeley, California - DoubleTree Hotel at the Berkeley Marina, Berkeley, United States Duration: 15 Oct 2017 → 17 Oct 2017 https://focs17.simons.berkeley.edu/ |
Conference
Conference | 58th Annual IEEE Symposium on Foundations of Computer Science (FOCS 2017), October 15-17, 2017, Berkeley, California |
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Abbreviated title | FOCS 2017 |
Country/Territory | United States |
City | Berkeley |
Period | 15/10/17 → 17/10/17 |
Internet address |
Keywords
- competitive analysis
- online algorithms
- weighted k-server