Using Parser to Extract Relationships - Natural Language Processing with Java - page 243

Relationship types

There are many possible relationship types. A few categories and examples of relationships
are found in the following table. An interesting site that contains a multitude of relation-
ships is Freebase ( https://www.freebase.com/ ) . It is a database of people, places, and things
organized by categories. The WordNet thesaurus ( http://wordnet.princeton.edu/ ) contains a
number of relationships.

Relationship Example

Personal father-of, sister-of, girlfriend-of

Organizational subsidiary-of, subcommittee-of

Spatial near-to, northeast-of, under

Physical part-of, composed-of

Interactions bonds-with, associates-with, reacts-with

Name Entity Recognition is a low level type of NLP classification that was covered in
Chapter 4 , Finding People and Things . However, many applications need to go beyond this
and identify different types of relationships. For example, when NER is applied to identify
individuals, then knowing that we are dealing with a person can further refine the relation-
ships present.

Once these entities have been identified, then links can be created to their containing docu-
ments or used as indexes. For question answering applications, named entities are often
used for answers. When a sentiment of text is determined, it needs to be attributed to some
entity.

For example, consider the following input:

He was the last person to see Fred.

Using OpenNLP NER as input with the preceding sentence, as we did in Chapter 4 , Find-
ing People and Things , we get the following output: