Title
Zips: mining compressing sequential patterns in streams
Abstract
We propose a streaming algorithm, based on the minimal description length (MDL) principle, for extracting non-redundant sequential patterns. For static databases, the MDL-based approach that selects patterns based on their capacity to compress data rather than their frequency, was shown to be remarkably effective for extracting meaningful patterns and solving the redundancy issue in frequent itemset and sequence mining. The existing MDL-based algorithms, however, either start from a seed set of frequent patterns, or require multiple passes through the data. As such, the existing approaches scale poorly and are unsuitable for large datasets. Therefore, our main contribution is the proposal of a new, streaming algorithm, called Zips, that does not require a seed set of patterns and requires only one scan over the data. For Zips, we extended the Lempel-Ziv (LZ) compression algorithm in three ways: first, whereas LZ assigns codes uniformly as it builds up its dictionary while scanning the input, Zips assigns codewords according to the usage of the dictionary words; more heaviliy used words get shorter code-lengths. Secondly, Zips exploits also non-consecutive occurences of dictionary words for compression. And, third, the well-known space-saving algorithm is used to evict unpromising words from the dictionary. Experiments on one synthetic and two real-world large-scale datasets show that our approach extracts meaningful compressing patterns with similar quality to the state-of-the-art multi-pass algorithms proposed for static databases of sequences. Moreover, our approach scales linearly with the size of data streams while all the existing algorithms do not.
Year
DOI
Venue
2013
10.1145/2501511.2501520
IDEA@KDD
Keywords
Field
DocType
sequential pattern,well-known space-saving algorithm,existing algorithm,compression algorithm,mdl-based approach,dictionary word,existing mdl-based algorithm,compress data,static databases,approach scales linearly,data stream,visual analytics
Data mining,Data stream mining,Streaming algorithm,Computer science,Visual analytics,Exploit,Redundancy (engineering),Artificial intelligence,Data compression,Sequential Pattern Mining,Machine learning,Fold (higher-order function)
Conference
Citations 
PageRank 
References 
2
0.38
6
Authors
5
Name
Order
Citations
PageRank
Hoang Thanh Lam11088.49
Toon Calders2133393.66
Jie Yang311618.47
Fabian Mörchen437217.94
Dmitriy Fradkin534419.25