Title
Dynamic beats fixed: on phase-based algorithms for file migration.
Abstract
In this paper, we construct a deterministic 4-competitive algorithm for the online file migration problem, beating the currently best 20-year old, 4.086-competitive MTLM algorithm by Bartal et al. (SODA 1997). Like MTLM, our algorithm also operates in phases, but it adapts their lengths dynamically depending on the geometry of requests seen so far. The improvement was obtained by carefully analyzing a linear model (factor-revealing LP) of a single phase of the algorithm. We also show that if an online algorithm operates in phases of fixed length and the adversary is able to modify the graph between phases, no algorithm can beat the competitive ratio of 4.086.
Year
DOI
Venue
2017
10.1145/3340296
international colloquium on automata, languages and programming
Keywords
DocType
Volume
File migration, competitive analysis, factor-revealing linear programs, online algorithms
Conference
abs/1609.00831
Issue
ISSN
Citations 
4
1549-6325
1
PageRank 
References 
Authors
0.36
9
3
Name
Order
Citations
PageRank
Marcin Bienkowski125427.18
Jaroslaw Byrka252331.45
Marcin Mucha327518.55