The document discusses various types of reference phenomena in discourse including: - Indefinite noun phrases introduce new entities, definite noun phrases refer to already mentioned entities, and pronouns refer to salient entities. - Pronominal reference can become ambiguous if the referent is not clear from the context. - Demonstratives like "this" and "that" behave differently than simple definite pronouns. - Referring expressions must be interpreted based on both the immediate discourse context and broader situational context.

1. NLP chapter 5
What is Disclosure?
Pragati Chandankhede
Asst Prof(KCCOEMSR)
19/3/2020

2. Definition
• Any language does not normally consist of isolated,
unrelated sentences, but instead of collocated, related
groups of sentences. We refer to such a group of
sentences as a discourse.
• Its of a particular sort: a monologue
• What is monologue ?
The communication flows in only one direction in a
monologue, that is, from the speaker to the hearer.
• What is dialogue?
Each participant periodically takes turn being a speaker and
hearer.
(dialogues generally consist of many different types of
communicative acts: asking questions, giving answers,
making corrections, and so forth.)

3. HCI and Disclosure ?
• A system capable of HCI will often employ a strategy to constrain the
conversation in ways that allow it to understand the user’s utterances
within a limited context of interpretation.
• How do hearers interpret discourse with such
ease? Can we build a computational model of
this process?

4. Example
• “I’d like to get from Boston to San Francisco, on
either December 5th or December 6th. It’s okay
if it stops in another city along the way.” the
system had to figure out that it denotes the
flight that the user wants to book in order to
perform the appropriate action. Similarly,
information extraction systems must frequently
extract information from utterances that
contain pronouns.

5. REFERENCE RESOLUTION
• Consider the example
“John went to Bill’s car dealership to check out an Acura Integra. He looked at it
for about an hour.”
The process by which REFERENCE speakers use expressions like John and he
in passage to denote a person named John.
• What is referent?
the entity that is referred to is called the referent
Eg., John is REFERENT
• What is referring expression?
It’s a Language that to perform reference.eg., John and he

6. • What is corefer?
Two referring expressions that are used to refer to the same entity are said
to corefer, thus John and he corefer in passage.
• What is anaphora?
• Reference to an entity that has been previously introduced into the
discourse is called anaphora.
• Eg., the pronouns he and it are therefore anaphoric.

7. Discourse context
• Considering the same example
• “John went to Bill’s car dealership to check out an Acura Integra. He
looked at it for about an hour.”
• You might say it, this, that, this car, that car, the car, the Acura, the
Integra, or my friend’s car, among many other possibilities.
• What is Discourse context?
• a variety of ways to refer to entities.

8. situational context
• Considering the same example
• “John went to Bill’s car dealership to check out an Acura Integra. He
looked at it for about an hour.”
• if the hearer has no prior knowledge of your
friend’s car, it has not been mentioned before,
such a context is said to be situational context.

9. Discourse model
• What it is?
• It is representations of the entities that have been referred to in the
discourse and the relationships in which they participate.
• Component
• 1. a method for constructing a discourse
model(evoked)
• 2. a method for mapping between the signals
that various referring expressions.(accessed)

10. Reference operation and relationship

11. What is Reference Phenomena?
• It is referring expression.
• types of referring expression:
1. indefinite noun phrases,
2. definite noun phrases,
3. pronouns,
4.demonstratives, and
5.one-anaphora.

12. Indefinite Noun Phrases
• Indefinite reference introduces entities that are
new to the hearer into the discourse context.
Evoke a representation for a new entity that
satisfies the given description into the discourse
model.
• The most common form of indefinite reference is
marked with the determiner a (or an), some, this.
• Eg.,
• I saw this awesome Acura Integra today.

13. Definite Noun Phrases
• Refer to an entity that is identifiable to the
hearer, either because it has already been
mentioned in the discourse context.
• Or
• uniqueness of the object is implied by the
description itself.
• Eg.,
• The fastest car in the Indianapolis 500 was an
Integra.

14. Pronouns
• Its about pronominalization, illustration.
• Here referent have a high degree of activation or salience(most noticeable)
in the discourse model.
• EG., consider the below -Pronominal reference which is the sentences
about persons or things
• a. John went to Bob’s party, and parked next to a beautiful
Acura Integra.
• b. He went inside and talked to Bob for more than an hour.
• c. Bob told him that he recently got engaged.
• d. ?? He also said that he bought it yesterday.
• d.’ He also said that he bought the Acura yesterday.
• Are we talking about bob party, or acura integra or John?
• This is said as losing the pronominal reference. Thus there is no more
degree of salience

15. Cataphora
• Its about the sequence that’s important to
form a phrase.
• e.g., check the pronoun he
• he may be approaching 37, but Jeff has no
plans to retire from the sport yet

16. Bound
• Pronouns also appear in quantified contexts in
which they are considered to be bound.
Eg.,
Every woman bought her Acura at the local
dealership.
Here her does not refer to some woman in
context

17. Demonstratives
• Demonstrative pronouns, like this and that,
behave somewhat differently than simple
definite pronouns like it.
Eg.,(talking about two car company)
I like this better than that.

18. One Anaphora
Its about Properties of definite and indefinite
reference.

19. Other Reference phenomena
1. Inferrables: focuses on evoked entity
• Eg., I almost bought an BMW today, but a door had a dent and the
engine seemed noisy.
• Eg., Mix the flour, butter, and water.
• a. Kneed the dough until smooth and shiny.
• b. Spread the paste over the blueberries.
• c. Stir the batter until all lumps are gone.
• Any of the expressions the dough (a solid), the batter (a liquid), and the
• paste (somewhere in between) can be used to refer to the result of the
actions
• described in the first sentence, but all imply different properties of this
result.

20. Other Reference phenomena
• Discontinuous Sets In some cases, references
using plural referring expressions
• like they and them ,refer to sets of entities
that are evoked together.
• Eg., John and Mary love their Acuras. They drive them all the
time.

21. Other Reference phenomena
• Generics: its being particular for all.
Eg.,Division BE student are smart. They are
talented too.
• Here they refer to all the BE student.

22. Simple way to remember by Example.