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Semi-structured data is becoming increasingly important with the introduction of XML and related languages and technologies. The recent shift from DTDs (document type deenitions) to XML-Schema for XML data highlights the importance of a schema deenition for semi-structured data applications. At the same time, there is a move to extend semi-structured data(More)
Data mining is generally considered the extraction and analysis of information from databases. With the rapid growth of XML data available online, mining XML data from the web is becoming important. In support of this trend, several encouraging attempts at developing methods for mining XML data have been proposed. However, efficiency and simplicity are(More)
Clustering is an important data mining task and has been explored extensively by a number of researchers for different application areas such as finding similarities in images, text data and bio-informatics data. Various optimization techniques have been proposed to improve the performance of clustering algorithms. In this paper we propose a novel algorithm(More)
If XML is to play the critical role of the lingua franca for Internet data interchange that many predict, it is necessary to start designing and adopting benchmarks allowing the comparative performance analysis of the tools being developed and proposed. The effectiveness of existing XML query languages has been studied by many, with a focus on the(More)
In the past decade, researchers have combined deductive and object-oriented features to produce systems that are powerful and have excellent modeling capabilities. More recently, an XML query language XTree was proposed. Queries written in XTree are more compact, more convenient to write and easier to understand than queries written in XPath. In this paper,(More)
We present declarative and procedural semantics for a deductive object-oriented language, Gulog. The declarative semantics is based on preferred minimal models. We describe both bottom-up and top-down query evaluation procedures and show that they are sound with respect to the declarative semantics. The results contribute to our understanding of the(More)
Semistructured data has become prevalent with the growth of the Internet. The development of new web applications that require efficient design and maintenance of large amounts of data makes it increasingly important to design " good " semistructured databases to prevent data redundancy and updating anomalies. However, it is not easy, even impossible, for(More)