The semantic Web conceptually encompasses the representation of data in Extensible Markup Language (XML)--the metadata that captures the ontology of the data represented--and logic for knowledge acquisition and decision support. This volume contains the lecture notes of seven tutorial papers from the 2009 Fifth International Summer School, the theme of which was tools for the reasoning Web--decision logics in the semantic Web.
The first paper is on description logics (DL) for representing conceptual knowledge in a formally consistent manner, with the Web ontology language (OWL) as the standard embodiment. The second paper is a general primer on answer set programming (ASP). ASP is based on declarative logic programming, an approach that extends back to the Prolog language. The third paper is on the logical foundations of XML and XQuery; XPath and XQuery are used to extract information from data represented in XML. The next two papers are connected through resource description framework (RDF) databases--RDF is one of the two core technologies in the semantic Web stack (along with SPARQL): the fourth paper is on the foundation of RDF databases, and the fifth paper is on their technology. The sixth paper may seem somewhat anomalous since it is on the technology of a social semantic desktop. Its connection is through capturing unstructured data available in a social network setting and the development of an ontology language for representation and query. The last paper is on DL-lite languages, databases, and ontologies. DL-lite languages keep the complexity of queries (and the related overhead) low, while still representing the ontology of the data.
Although the back cover claims that “the objective of the book is to provide a coherent introduction to semantic Web methods and research issues with a particular emphasis on reasoning,” the proper way to read this statement is: “a coherent introduction to research issues,” with an emphasis on “research issues.” It is not, in fact, an “introduction” to the semantic Web. This observation is not meant as a criticism, but as a caution: before undertaking this book, potential readers should already be familiar with XML, OWL, RDF, XPath, and XQuery. Readers who have a good command of the basics will find this book a good entry point into contemporary research.