A similarity query is to find from a collection of items those that are similar to a given query item. Answering similarity queries is important in applications such as DNA sequence assembly, record linkage, and query relaxation, where errors could occur in queries as well as the data. The wide relevance of similarity queries presents to us application-specific constraints and desiderata. In this thesis, we develop and evaluate indexes and algorithms for answering such queries efficiently in the context of four different settings. First, we present a DNA-specific alignment method whose primary focus is on the speed of query execution. Our results show a performance improvement of 2-10X compared to existing state-of-the-art packages. Second, we develop a flexible compression technique for reducing the size of an inverted index to a given amount of space while retaining efficient query processing. In our experimental evaluation we could reduce the index size up to 60% without sacrificing query response times. Third, we study external-memory solutions well-suited for database management systems, where the data and indexes are stored on disk, and demonstrate a substantial benefit over alternative methods. Fourth, we discuss how we incorporated some of our solutions into the ASTERIX parallel database system to optimize similarity queries via secondary indexes. We elaborate on our design choices and query-processing capabilities, and conclude with experiments on large-scale data.
|Commitee:||Carey, Michael J., Mehrotra, Sharad|
|School:||University of California, Irvine|
|Department:||Computer Science - Ph.D.|
|School Location:||United States -- California|
|Source:||DAI-B 74/06(E), Dissertation Abstracts International|
|Keywords:||Asterix, Databases, Hyracks, Indexing, Join queries, Parallel databases, Similarity selection|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be