CS626-449: NLP, Speech and Web-Topics-in-AI

Pushpak BhattacharyyaCSE Dept., IIT Bombay

Lecture 35: Semantic Relations; UNL; Towards Dependency Parsing

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Web at a glance

Google indexes more than 8 billion pages

Dominated by English Large part of world is deprived of

this knowledge

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Search Engines Today

Keyword based Irrelevant results

Meaning not taken into account

Language specific No search possible across language No translation possible

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Future of the World Wide Web

WWW

User

Translationinterface

User

User

User

Translationinterface

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Features

Meaning based More relevant results

Multilingual Query in English Fetch document in Hindi Show it in English

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Machine Translation

Translate from one language to other

Two approaches Direct

One step Using Intermediate language

Two step

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Interlingua Interlingua

Intermediate language for machine translation

Step one Convert from source language text to

interlingua Step two

Produce target langauge text from interlingua

UNL : an interlingua in UNL system

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Internet for the Masses

Internet

Spanishinterface

English viewer

Hindi viewer

English interface

Spanishviewer

Hindi interfac

e

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A Semantic Graph

in: modifiera: indefinite

the: definite

student

past tense

agent

bought

objecttime

computer

new

June

modifier

The student bought a new computer in June.

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UNL representation

Ram is reading the newspaper

Representation of Knowledge

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Knowledge Representation

Ram

read

newspaper

agt obj

UNL Graph - relations

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Knowledge Representation

Ram(iof>person)

read(icl>interpret)

newspaper(icl>print_media)

UNL Graph - UWs

agt obj

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Knowledge Representation

Ram(iof>person)

read(icl>interpret)

newspaper(icl>print_media)

@entry@present@progress

@def

Ram is reading the newspaper

UNL graph - attributes

agt obj

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The boy who works here went to school

plt

agt@ entry @ past

school(icl>institution)

go(icl>move)

boy(icl>person)

work(icl>do)

here

@ entry

agt plc

:01

Another Example

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UNL System

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The World-wide Universal Networking Language (UNL) Project

UNL

English Russian

Japanese

Hindi

Spanish

Language independent meaning representation.

Marathi

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The UNL System: An Overview

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Universal Networking Language

Universal Words (UWs) Relations Attributes Knowledge Base

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UNL Graph

obj

agt

@ entry @ past

minister(icl>person)

forward(icl>send)

mail(icl>collection)

He(icl>person)

@def

@def

gol

He forwarded the mail to the minister.

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UNL Expression

agt (forward(icl>send).@ entry @ past, he(icl>person))

obj (forward(icl>send).@ entry @ past, minister(icl>person))

gol (forward(icl>send ).@ entry @ past, mail(icl>collection). @def)