A general XML index can itself be sizable leading to low efficiency. To alleviate this predicament, frequently asked queries can be indexed by a database system. They are referred to as views. Answering queries using materialized views is always cheaper than evaluating over the base data. Traditional techniques solve this problem by considering only a single view. We approach this problem by exploiting the potential relationships of multiple views, which can be used together to answer a given query. Experiments show that significant performance gain can be achieved from multiple views. / A XML query can be decomposed to a sequence of structural joins (e.g., parent/child and ancestor/descendant) and content joins. Thus, structural join optimization is a key to improving join-based evaluation. We optimize structural join with two orthogonal methods: partition-based method exploits the spatial specialities of XML encodings by projecting them on a plane; and location-based method improves structural join by accurately pruning all irrelevant nodes, which cannot produce results. / As XML (eXtensible Markup Language) becomes a universal medium for data exchange over the Internet, efficient XML query processing is now the focus of considerable research and development activities. This thesis describes works toward efficient XML query evaluation and optimization in native XML databases. / XML indexes are widely studied to evaluate XML queries and in particular to accelerate join-based approaches. Index-based approaches outperform join-based approaches (e.g., holistic twig join) if the queries match the index. Existing XML indexes can only support a small set of XML queries because of the varieties in XML query representations. A XML query may involve child-axis only, both child-axis and branches, or additional descendant-or-self-axis but only in the query root. We propose novel indexes to efficiently support a much wider range of XML queries (with /, //, [], *). / Tang, Nan. / "December 2007." / Advisers: Kam-Fei Wong; Jeffrey Xu Yu. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4861. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 152-163). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Cheung Wing Hang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 107-112). / Abstracts in English and Chinese. / Abstract --- p.ii / Abstract in Chinese --- p.iv / Acknowledgments --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Firewall Issue in Distributed Systems --- p.2 / Chapter 1.2 --- Heterogeneous Communication Protocols --- p.4 / Chapter 1.3 --- Translator for Converting Interface Definition to Flexible XML --- p.8 / Chapter 1.4 --- An Implementation of a Scalable Mediator Query System --- p.9 / Chapter 1.5 --- Our Contributions --- p.9 / Chapter 1.6 --- Outline of This Thesis --- p.10 / Chapter 2 --- Related Work and Technologies --- p.12 / Chapter 2.1 --- Overview of XML Technology --- p.12 / Chapter 2.1.1 --- XML Basic Syntax --- p.13 / Chapter 2.1.2 --- DTD: The Grammar Book --- p.15 / Chapter 2.1.3 --- Representing Complex Data Structures --- p.17 / Chapter 2.2 --- Overview of Java Servlet Technology --- p.18 / Chapter 2.3 --- Overview of Simple Object Access Protocol --- p.20 / Chapter 2.4 --- Overview of XML-RPC --- p.21 / Chapter 2.5 --- Overview of XIOP --- p.22 / Chapter 3 --- Using XML and Servlets to Support CORBA Calls --- p.24 / Chapter 3.1 --- Objective --- p.24 / Chapter 3.2 --- General Concept of Our Mechanism --- p.25 / Chapter 3.2.1 --- At Client Side --- p.27 / Chapter 3.2.2 --- At Server Side --- p.28 / Chapter 3.3 --- Data in Transmission --- p.30 / Chapter 3.3.1 --- Using XML --- p.30 / Chapter 3.3.2 --- Format of Messages in Transmission --- p.30 / Chapter 3.4 --- Supporting Callbacks in CORBA Systems --- p.33 / Chapter 3.4.1 --- What is callback? --- p.33 / Chapter 3.4.2 --- Enhancement to Allow Callbacks --- p.34 / Chapter 3.5 --- Achieving Transparency with Add-on Components --- p.37 / Chapter 4 --- A Translator to Convert CORBA IDL to XML --- p.39 / Chapter 4.1 --- Introduction to CORBA IDL --- p.39 / Chapter 4.2 --- Mapping from IDL to XML --- p.40 / Chapter 4.2.1 --- IDL Basic Data Types --- p.41 / Chapter 4.2.2 --- IDL Complex Data Types --- p.42 / Chapter 4.2.3 --- IDL Interface --- p.48 / Chapter 4.2.4 --- Attributes --- p.48 / Chapter 4.2.5 --- Operations (Methods) --- p.49 / Chapter 4.2.6 --- Exceptions --- p.50 / Chapter 4.2.7 --- Inheritance --- p.51 / Chapter 4.2.8 --- IDL Modules --- p.52 / Chapter 4.2.9 --- A Sample Conversion --- p.52 / Chapter 4.3 --- Making a Request or Response --- p.53 / Chapter 4.4 --- Code Generation for Add-on Components --- p.54 / Chapter 4.4.1 --- Generation of Shadow Objects --- p.54 / Chapter 4.4.2 --- Generation of Servlet Components --- p.55 / Chapter 5 --- Communication in Heterogeneous Distributed Environments --- p.58 / Chapter 5.1 --- Objective --- p.58 / Chapter 5.2 --- General Concept --- p.60 / Chapter 5.3 --- Case Study 1 - Distributed Common Object Model --- p.61 / Chapter 5.3.1 --- Brief Overview of Programming in DCOM --- p.61 / Chapter 5.3.2 --- Mapping the Two Different Interface Definitions --- p.63 / Chapter 5.3.3 --- Sample Architecture of Communicating Between DCOM and CORBA --- p.66 / Chapter 5.4 --- Case Study 2 - Java Remote Methods Invocation --- p.67 / Chapter 5.4.1 --- Brief Overview of Programming in Java RMI --- p.67 / Chapter 5.4.2 --- Mapping the Two Different Interface Definitions --- p.69 / Chapter 5.4.3 --- Sample Architecture of Communicating Between JavaRMI and CORBA --- p.71 / Chapter 5.5 --- Be Generic: Binding with the WEB --- p.72 / Chapter 6 --- Building a Scalable Mediator-based Query System --- p.74 / Chapter 6.1 --- Objectives --- p.74 / Chapter 6.2 --- Introduction to Our Mediator-based Query System --- p.76 / Chapter 6.2.1 --- What is mediator? --- p.76 / Chapter 6.2.2 --- The Architecture of our Mediator Query System --- p.77 / Chapter 6.2.3 --- The IDL Design of the Mediator System --- p.79 / Chapter 6.2.4 --- Components in the Query Mediator System --- p.80 / Chapter 6.3 --- Helping the Mediator System to Expand Across the Firewalls --- p.83 / Chapter 6.3.1 --- Implementation --- p.83 / Chapter 6.3.2 --- Across Heterogeneous Systems with DTD --- p.87 / Chapter 6.4 --- Adding the Callback Feature to the Mediator System --- p.89 / Chapter 6.5 --- Connecting our CORBA System with Other Environments --- p.90 / Chapter 6.5.1 --- Our Query System in DCOM --- p.91 / Chapter 6.5.2 --- Our Query System in Java RMI --- p.92 / Chapter 6.5.3 --- Binding Heterogeneous Systems --- p.93 / Chapter 7 --- Evaluation --- p.95 / Chapter 7.1 --- Performance Statistics --- p.95 / Chapter 7.1.1 --- Overhead in other methods --- p.97 / Chapter 7.2 --- Means for Enhancement --- p.98 / Chapter 7.2.1 --- Connection Performance of HTTP --- p.98 / Chapter 7.2.2 --- Transmission Data Compression --- p.99 / Chapter 7.2.3 --- Security Concern --- p.99 / Chapter 7.3 --- Advantages of Using Our Mechanism --- p.101 / Chapter 7.4 --- Disadvantages of Using Our Mechanism --- p.102 / Chapter 8 --- Conclusion --- p.104

by Fung Tze Wa. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 92-96). / Abstracts in English and Chinese. / Abstract in English --- p.i / Abstract in Chinese --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv-vi / List of Figures --- p.vii-ix / List of Tables --- p.x / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Motivation --- p.3 / Chapter 1.3 --- Purposes of this Research --- p.6 / Chapter 1.4 --- Contribution of this Research --- p.7 / Chapter 1.5 --- Outline of the Thesis --- p.9 / Chapter Chapter 2 --- Literature Review And Research Issues / Chapter 2.1 --- Introduction --- p.11 / Chapter 2.2 --- Spatial Access Methods --- p.14 / Chapter 2.2.1 --- R-Tree --- p.15 / Chapter 2.2.2 --- R*-Tree --- p.19 / Chapter 2.2.3 --- R+-Tree --- p.21 / Chapter 2.3 --- Spatial Network Analysis --- p.22 / Chapter 2.4 --- Nearest Neighbor Queries --- p.23 / Chapter 2.5 --- Summary --- p.25 / Chapter Chapter 3 --- Data Preparation / Chapter 3.1 --- "Introduction (XML, GML), XML indexing" --- p.26 / Chapter 3.2 --- Spatial data from Lands Department --- p.31 / Chapter 3.3 --- Graph representation for Road Network data --- p.32 / Chapter 3.4 --- Summary --- p.35 / Chapter Chapter 4 --- XML Indexing for Spatial Data / Chapter 4.1 --- Introduction --- p.36 / Chapter 4.2 --- STR Packed R-Tree --- p.38 / Chapter 4.2.1 --- Implementation --- p.39 / Chapter 4.2.2 --- Experimental Result --- p.41 / Chapter 4.3 --- Summary --- p.48 / Chapter Chapter 5 --- Spatial Network / Chapter 5.1 --- Introduction --- p.50 / Chapter 5.2 --- CCAM: Connectivity-Clustered Access Method --- p.53 / Chapter 5.3 --- Shortest Path in Spatial Network --- p.56 / Chapter 5.4 --- A New Algorithm Specially for Partitioning /Clustering Network --- p.63 / Chapter 5.5 --- A New Simple heuristic for Shortest Path Problem for Spatial Network --- p.70 / Chapter 5.6 --- Summary --- p.74 / Chapter Chapter 6 --- Nearest Neighbor Queries / Chapter 6.1 --- Introduction --- p.76 / Chapter 6.2 --- Modified Algorithm for Nearest Neighbor Queries --- p.78 / Chapter 6.3 --- Summary --- p.83 / Chapter Chapter 7 --- Conclusion and Future Work / Chapter 7.1 --- Conclusion --- p.84 / Chapter 7.2 --- Future Work --- p.85 / Appendix Space Driven Algorithm / Chapter A.1 --- Introduction --- p.87 / Chapter A.2 --- Fixed Grid --- p.88 / Chapter A.3 --- Z-curve --- p.89 / Chapter A.4 --- Hilbert curve --- p.90 / Chapter A.5 --- Conclusion --- p.91 / Bibliography --- p.92

Abstract not available

Recent years have seen a surge in the popularity of XML, a markup language for representing semi-structured data. Some of this popularity can be attributed to the success that the semi-structured data model has had in environments where the relational data model has been insufficiently expressive. Concomitant with XMLs growing popularity, the world of database research has seen the rebirth of interest in tree-structured, hierarchical database systems. This thesis analyzes several problems that arise when constructing XML data management systems, particularly in the case where such systems must handle dynamic content. In the first chapter, we consider the problem of incremental schema validation, which arises in almost any XML database system. We build upon previous work by finding several classes of schemas for which very efficient algorithms exist. We also develop an algorithm that works for any schema, and prove that it is optimal. In the second chapter, we turn to the problem of improving query evaluation times on extremely large database systems. In particular, we boost the performance of the structural and twig joins, fundamental XML query evaluation techniques, through the use of an adaptive index. This index tunes itself to the query workload, providing a 20-80% boost in speed for these join operators. The adaptive nature of the index also allows updates to the database to be easily tracked. While accurate selectivity estimation is a critical problem in any database system due to its importance in choosing optimal query plans, there has been very little work on selectivity estimation in the presence of updates. We ask whether it is possible to design a structure for selectivity in XML databases that is updateable, and can return results with theoretically sound error guarantees. Through a combination of lower and upper bounds, we give strong evidence suggesting that this is unlikely in practice. Motivated by these results, we then develop a heuristic selectivity estimation structure for XML databases. This structure is the first such synopsis that can handle all aspects of core XPath, and is also updateable. Our experimental results demonstrate the efficacy of the approach.

Thesis (M.S.)--University of Florida, 2001. / Title from first page of PDF file. Document formatted into pages; contains x, 75 p.; also contains graphics. Vita. Includes bibliographical references (p. 71-74).

Thesis (M.Sc.)--York University, 2008. Graduate Programme in Computer Science. / Typescript. Includes bibliographical references (leaves 147-152). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38782

Thesis (Ph. D.)--Florida State University, 2003. / Advisor: Dr. Gary Burnett, Florida State University, School of Information Studies. Title and description from dissertation home page (viewed Apr. 06, 2004). Includes bibliographical references.

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 107-120). Also available in electronic version. Access restricted to campus users.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 115-119). Also available in print.