Title
Edit distance to monotonicity in sliding windows
Abstract
Given a stream of items each associated with a numerical value, its edit distance to monotonicity is the minimum number of items to remove so that the remaining items are non-decreasing with respect to the numerical value. The space complexity of estimating the edit distance to monotonicity of a data stream is becoming well-understood over the past few years. Motivated by applications on network quality monitoring, we extend the study to estimating the edit distance to monotonicity of a sliding window covering the w most recent items in the stream for any w≥1. We give a deterministic algorithm which can return an estimate within a factor of (4+ε) using $O(\frac{1}{\epsilon ^2} \log^2(\epsilon w))$ space. We also extend the study in two directions. First, we consider a stream where each item is associated with a value from a partial ordered set. We give a randomized (4+ε)-approximate algorithm using $O(\frac{1}{\epsilon^2} \log \epsilon^2 w \log w)$ space. Second, we consider an out-of-order stream where each item is associated with a creation time and a numerical value, and items may be out of order with respect to their creation times. The goal is to estimate the edit distance to monotonicity with respect to the numerical value of items arranged in the order of creation times. We show that any randomized constant-approximate algorithm requires linear space.
Year
DOI
Venue
2011
10.1007/978-3-642-25591-5_58
international symposium on algorithms and computation
Keywords
DocType
Volume
deterministic algorithm,log w,numerical value,out-of-order stream,creation time,epsilon w,approximate algorithm,space complexity,data stream,linear space,edit distance
Conference
abs/1111.5386
ISSN
Citations 
PageRank 
0302-9743
3
0.45
References 
Authors
13
6
Name
Order
Citations
PageRank
Ho-Leung Chan147125.23
Tak-Wah Lam21860164.96
Lap-Kei Lee340621.59
Jiangwei Pan4343.24
Hing-Fung Ting57611.69
Qin Zhang669342.56