Maged El-Sayed

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Outlook. We present multiple XQuery optimization based on materialized XML view technology in the Rainbow system. In this demo we in particular show: (1) Rainbow's support for defining and incrementally maintaining materialized XQuery views, (2) XQuery optimization by query rewriting to use materialized views, (3) Performing multiple query optimization by(More)
Mining frequent patterns is an important component of many prediction systems. One common usage in web applications is the mining of users' access behavior for the purpose of predicting and hence pre-fetching the web pages that the user is likely to visit. In this paper we introduce an efficient strategy for discovering frequent patterns in sequence(More)
Modern data sources, including structural and semi-structural sources, often export XML views over base data, and at times may materialize their views by storing the XML query result to provide faster data access. It is typically more efficient to maintain a view by incrementally propagating the base changes to the view than by re-computing it from scratch.(More)
Materialized XML views are a popular technique for integrating data from possibly distributed and heterogeneous data sources. However, the problem of the incremental maintenance of such XML views poses new challenges which to date remain unaddressed. One, XML views not only filter the data, but may radically restructure it to construct new XML nested(More)
Query processing over XML data sources has emerged as a popular topic. XML is an ordered data model and XQuery expressions return results that have a well-defined order. However little work on how order is supported in XML query processing has been done to date. In this paper we study the challenges related to handling order in the XML context, namely(More)
Materializing the contents of views has important applications including providing fast access to derived database repositories, optimizing query processing based on cached results, and increasing availability. Maintaining the consistency between materialized views and their base data in the presence of source updates is important to ensure that the(More)
Many applications, like materialized view maintenance and stream query processing, construct views incrementally over data sources. This results in computed pieces of objects that need to be merged by fusing corresponding objects together. This problem is challenging when dealing with XML data for many reasons including the hierarchical and semi-structured(More)
Query processing over XML data sources has emerged as a popular topic. XML is an ordered data model and XQuery expressions return results that have a well-defined order. However little work on how order is supported in XML query processing has been done to date. In this paper we study the challenges related to handling order in the XML context, namely(More)