While the information resources on the Web are vast, the sources are often hard to find, painful to use, and difficult to integrate. We have developed the Heracles framework for building Web-based information assistants. This framework provides the infrastructure to rapidly construct new applications that extract information from multiple Web sources and interactively integrate the data using a dynamic, hierarchical constraint network. This paper describes the core technologies that comprise the framework, including information extraction, hierarchical template representation, and constraint propagation. In addition, we present an application of this framework, the Travel Assistant, which is an interactive travel planning system. We also briefly describe our experience using the same framework to build a second application, the WorldInfo Assistant, which extracts and integrates geographic-related data about countries thorughout the world. We believe these types of information assistan...
Craig A. Knoblock, Steven Minton, José Luis