A Community Web portal is a set of tools for a community of people who want to share information on a certain domain via the Web. The backbone of this system is an ontology which is understood by all members of the community and used as the common interface component for integrating, querying, structuring and exchanging information. This paper describes a simple but nevertheless powerful langua...

XPath is a language for addressing parts of an XML document. It is used in many XML query languages and it can be used by itself for querying XML documents. While XPath is, in general, efficient for querying individual XML documents, it lacks the features for querying over collections of documents or joining parts of the same document. As the amount of complex document-centric XML data is conti...

We consider the problem of evaluating a large number of XPath expressions on an XML stream. Our main contribution consists in showing that Deterministic Finite Automata (DFA) can be used effectively for this problem: in our experiments we achieve a throughput of about 5.4MB/s, independent of the number of XPath expressions (up to 1,000,000 in our tests). The major problem we face is that of the...

Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML. Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere. XPath language is the result of an effort to provide address parts of an XML document. In support of this ...

Querying XML data is based on the specification of structural patterns which in practice are formulated using XPath. Usually, these structural patterns are in the form of trees (Tree-Pattern Queries – TPQs). Requirements for flexible querying of XML data including XML data from scientific applications have motivated recently the introduction of query languages that are more general and flexible...

This paper presents a uniform approach to data extraction from syntactically annotated corpora encoded in XML. XQuery, which incorporates XPath, has been designed as a query language for XML. The combination of XPath and XQuery offers flexibility and expressive power, while corpus specific functions can be added to reduce the complexity of individual extraction tasks. We illustrate our approach...

We present a new approach for accelerating the execution of XPath expressions using parameterized materialized XPath views (PXV). While the approach is generic we show how it can be utilized in an XML extension for relational database systems. Furthermore we discuss an algorithm for automatically determining the best PXV candidates to materialize based on a given workload. We evaluate our appro...

We present a sound and complete rule set for determining whether sorting by document order and duplicate removal operations in the query plan of XPath expressions are unnecessary. Additionally we define a deterministic automaton that illustrates how these rules can be translated into an efficient algorithm. This work is an important first step in the understanding and tackling of XPath/XQuery o...

A common task that is often needed in many software development tools is the capability to search the artifact that is being created in a flexible and efficient manner. However, this capability is typically absent in metaprogrammable modeling tools, which can be a serious disadvantage as the size of a model increases. As a remedy, we introduce a method to search domain models using XPath – a Wo...