Declaratively querying and visualizing knowledge bases in XML

The maintenance of large knowledge systems usually is a rather complex task. In this paper we will show that extensions or modifications of a knowledge base can be supported by appropriate visualizations techniques, e.g. by illustrating dependencies within the considered knowledge. In particular, we introduce a declarative approach for querying and visualizing rule-based knowledge represented as XML documents; a knowledge engineer can extract and visually inspect parts of the knowledge base by ad-hoc declarations in a flexible manner.