In: International Journal on Document Analysis and Recognition (IJDAR) 3 4 Seiten 248-260 Springer 5/2001.
Knowledge-based systems for document analysis and understanding (DAU) are quite useful whenever analysis has to deal with the changing of free-form document types which require different analysis components. In this case, declarative modeling is a good way to achieve flexibility. An important application domain for such systems is the business letter domain. Here, high accuracy and the correct assignment to the right people and the right processes is a crucial success factor. Our solution to this proposes a comprehensive knowledge-centered approach: we model not only comparatively static knowledge concerning document properties and analysis results within the same declarative formalism, but we also include the analysis task and the current context of the system environment within the same formalism. This allows an easy definition of new analysis tasks and also an efficient and accurate analysis by using expectations about incoming documents as context information. The approach described has been implemented within the VOPR (VOPR is an acronym for the Virtual Office PRototype.) system. This DAU system gains the required context information from a commercial workflow management system (WfMS) by constant exchanges of expectations and analysis tasks. Further interaction between these two systems covers the delivery of results from DAU to the WfMS and the delivery of corrected results vice versa.