Coreference Resolution Tools : A first look by Sharmila G Sivakumar.
From the post:
Coreference is where two or more noun phrases refer to the same entity. This is an integral part of natural languages to avoid repetition, demonstrate possession/relation etc.
Eg: Harry wouldn’t bother to read “Hogwarts: A History” as long as Hermione is around. He knows she knows the book by heart.
The different types of coreference includes:
Noun phrases: Hogwarts A history <- the book
Pronouns : Harry <- He
Possessives : her, his, their
Demonstratives: This boyCoreference resolution or anaphor resolution is determining what an entity is refering to. This has profound applications in nlp tasks such as semantic analysis, text summarisation, sentiment analysis etc.
In spite of extensive research, the number of tools available for CR and level of their maturity is much less compared to more established nlp tasks such as parsing. This is due to the inherent ambiguities in resolution.
A bit dated (2010) now but a useful starting point for updating. (Specific to medical records, see: Evaluating the state of the art in coreference resolution for electronic medical records. Other references you would recommend?)
Sharmila goes on to compare the results of using the tools on a set text so you can get a feel for the tools.