Deep grammars that include tokenization, morphology, syntax, and semantic layers have obtained broad coverage in conjunction with high efficiency. This allows them to play a crucial role in applications. However, these grammars are often developed as a general purpose grammar, expecting standard input, and have to be specialized for the application domain. This paper discusses some engineering tools that are used in the XLE grammar development platform to allow for domain specialization. It provides examples of techniques used to allow specialization via overlay grammars at the level of tokenization, morphology, syntax, the lexicon, and semantics. As an example, the paper focuses on the use of the broad coverage, general purpose ParGram English grammar and semantics in the context of an Intelligent Document Security Solutions (IDSS) system. Within this system, the grammar is used to automatically identify sensitive entities and relations among entities, which can then be redacted to protect the content.
King, T. H.; Maxwell, J. T. Overlay mechanisms for multi-level deep processing applications. Proceedings of GEAF (Grammar Engineering Across Frameworks) Workshop; 2007 July 13-15; Stanford, CA.