T-Rex (Trainable Relation Extraction) is a highly configurable machine learning-based Information Extraction from Text framework, which includes tools for document classification, entity extraction and relation extraction.
RelEx, a narrow-AI component of OpenCog, is an English-language semantic relationship extractor, built on the Carnegie-Mellon link parser. It can identify subject, object, indirect object and many other dependency relationships between words in a sentence; it generates dependency trees, resembling those of dependency grammars.
D. Roth, M. Sammons, and V. Vydiswaran. Proceedings of the ACL-IJCNLP 2009 Conference Short Papers, page 57--60. Suntec, Singapore, Association for Computational Linguistics, (August 2009)