INTRODUCTION TO ARTIFICIAL INTELLIGENCE Massimo Poesio LAB 9: WORDNET

COMMONSENSE KNOWLEDGE SOURCES FOR AI / NLP There are now several sources of commonsense knowledge that we can use to study its role in reasoning / develop systems able to use commonsense knowledge The best known is WordNet, a lexical database based on semantic networks developed by George Miller and his collaborators in Princeton

A LEXICAL RESOURCE BUILT ON SEMANTIC NETWORK PRINCIPLES WordNet is a LEXICAL DATABASE created at Princeton Freely available for research from the Princeton site It contains information about a variety of SEMANTICAL RELATIONS Three sub-databases (supported by psychological research as early as (Fillenbaum and Jones, 1965)) NOUNs VERBS ADJECTIVES and ADVERBS Each database organized around SYNSETS 2004/05 ANLE

The noun database About 90,000 forms, 116,000 senses Relations: hypernym breakfast -> meal hyponym meal -> lunch has-member faculty -> professor member-of copilot -> crew has-Part table -> leg part-of course -> meal antonym leader -> follower 2004/05 ANLE

USING WN ONLINE http://wordnetweb.princeton.edu/perl/webwn Example: CELL PHONE

EXERCISE 1 Find the entry for ROBOT

LEXICAL RELATIONS IN WORDNET Wordnet contains information about lexical relations between MEANINGS (more on meanings below) The type of lexical relations depends on the type of lexical entry

LEXICAL RELATIONS FOR NOUNS ISA (hypernymy) PART-OF (meronymy)

TAXONOMIC INFORMATION IN WORDNET WordNet is a very rich source of taxonomic information This information can be found by following HYPERNYMY links

Hypernyms 2 senses of robin                                                        Sense 1 robin, redbreast, robin redbreast, Old World robin, Erithacus rubecola -- (small Old World songbird with a reddish breast)        => thrush -- (songbirds characteristically having brownish upper plumage with a spotted breast)            => oscine, oscine bird -- (passerine bird having specialized vocal apparatus)                => passerine, passeriform bird -- (perching birds mostly small and living near the ground with feet having 4 toes arranged to allow for gripping the perch; most are songbirds; hatchlings are helpless)                    => bird -- (warm-blooded egg laying vertebrates characterized by feathers and forelimbs modified as wings)                        => vertebrate, craniate -- (animals having a bony or cartilaginous skeleton with a segmented spinal column and a large brain enclosed in a skull or cranium)                            => chordate -- (any animal of the phylum Chordata having a notochord or spinal column)                                => animal, animate being, beast, brute, creature, fauna -- (a living organism characterized by voluntary movement)                                    => organism, being -- (a living thing that has (or can develop) the ability to act or function independently)                                        => living thing, animate thing -- (a living (or once living) entity)                                            => object, physical object --                                                 => entity, physical thing -- 2004/05 ANLE

EXERCISE 2 Find the hypernyms of ROBOT

UPPER ONTOLOGY IN WORDNET The noun hierarchy is divided in distinct hierarchies, each with its top element

• {act,action,activity} • {animal,fauna} • {artifact} • {attribute,property} • {body,corpus} • {cognition,knowledge} • {communication} • {event,happening} • {feeling,emotion} • {food} • {group,collection} • {location,place} • {motive} • {natural object} • {natural phenomenon} • {person,human being} • {plant,flora} • {possession} • {process} • {quantity,amount} • {relation} • {shape} • {state,condition} • {substance} • {time}

MERONYMY IN WORDNET WordNet contains information about PARTS Stored as information about MERONYMS Example: TREE

EXERCISE 3 Find the parts of house Find the parts of building Find the parts of car

Meronymy wn beak –holon Holonyms of noun beak 1 of 3 senses of beak beak, bill, neb, nib PART OF: bird 2004/05 ANLE

EXERCISE 4 Find the entry of bank

THE ORGANIZATION OF THE LEXICON “eat” “eats” EAT-LEX-1 eat0600 eat0700 “ate” “eaten” WORD-FORMS LEXEMES SENSES 2004/05 ANLE

The organization of the lexicon stock0100 STOCK-LEX-1 stock0200 STOCK-LEX-2 stock0600 “stock” stock0700 STOCK-LEX-3 stock0900 stock1000 WORD-STRINGS LEXEMES SENSES 2004/05 ANLE

Synonymy cheap0100 “cheap” …. …… cheapXXXX inexp0900 “inexpensive” CHEAP-LEX-1 “cheap” …. CHEAP-LEX-2 …… cheapXXXX INEXP-LEX-3 inexp0900 “inexpensive” inexpYYYY WORD-STRINGS LEXEMES SENSES 2004/05 ANLE

Synsets Senses (or `lexicalized concepts’) are represented in WordNet by the set of words that can be used in AT LEAST ONE CONTEXT to express that sense / lexicalized concept: the SYNSET E.g., {chump, fish, fool, gull, mark, patsy, fall guy, sucker, shlemiel, soft touch, mug} (gloss: person who is gullible and easy to take advantage of) 2004/05 ANLE

EXERCISE 5 Find the senses of hand, palm, slick, and stock.

EXERCISE 6 Find the hypernyms of LAW

The verb database About 10,000 forms, 20,000 senses Relations between verb meanings: Hypernym fly-> travel Troponym Walk -> stroll Entails Snore -> sleep Antonym Increase -> decrease 2004/05 ANLE

Relations between verbal meanings V1 ENTAILS V2 when Someone V1 (logically) entails Someone V2 - e.g., snore entails sleep TROPONYMY when To do V1 is To do V2 in some manner - e.g., limp is a troponym of walk 2004/05 ANLE

EXERCISE 7 Find the antonyms of accelerate

The adjective and adverb database About 20,000 adjective forms, 30,000 senses 4,000 adverbs, 5600 senses Relations: Antonym (adjective) Heavy <-> light Antonym (adverb) Quickly <-> slowly 2004/05 ANLE

EXERCISE 8 Find the antonyms of dangerous

How to use Can also use online Command line: Getting WordNet: http://wordnet.princeton.edu/ Can also use online Command line: Get synonyms: wn –synsn bank Get hypernyms: wn –hypen robin (also for adjectives and verbs): get antonyms wn –antsa right 2004/05 ANLE

WORDNET FOR OTHER LANGUAGES MultiWordNet (multiwordnet.fbk.eu) A Multilingual WordNet Italian WordNet Synsets aligned with English WordNet (1.6) whenever possibile Compatible versions developed for Hebrew, Portuguese, Romanian and Spanish

WORDNET AND DOLCE The LOA group has been

OTHER SOURCES OF COMMONSENSE KNOWLEDGE OpenCyc: http://www.opencyc.org/ ConceptNet http://conceptnet.media.mit.edu/ Discussed next week DBPedia: http://dbpedia.org/

READINGS C. Fellbaum, 1998. WordNet. MIT press