6 Nov 2001IS202: Information Organization and Retrieval Information Extraction Ray Larson & Warren...
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Transcript of 6 Nov 2001IS202: Information Organization and Retrieval Information Extraction Ray Larson & Warren...
Information Extraction
Ray Larson & Warren Sack
IS202: Information Organization and Retrieval
Fall 2001
UC Berkeley, SIMS
lecture author: Warren Sack
Cognitive Science
• 10/30/01 – AI, knowledge representation and common sense
• 11/01/01 – Computational Linguistics, Cognitive Psychology and Lexical Knowledge
• 11/06/01 – AI and information extraction• 11/08/01 – Linguistics, Philosophy,
Psychology, categories, and cognition
Last Time
• Lexical relations– Linguistics
• Two approaches to semantics: – Compositional– Relational
– Psycholinguistics
• WordNet– Description– Structure– Applications
Levels of Linguistic Analysis
• Sentences– Phonological/Morphological analysis– Syntactic analysis– Semantic analysis
• More than one sentence– Pragmatic analysis
Pragmatics• Deixis
– E.g., “I’ll be back in an hour” depends upon the time of the utterance.
• Conversational implicature– A: “Can you tell me the time?”– B: “Well, the milkman has come.” [I don’t know exactly, but
perhaps you can deduce it from some extra information I give you.]
• Presupposition– “Are you still such a bad driver?”
• Speech acts– Constatives vs. performatives– e.g., “I second the motion.”
• Conversational Structure– E.g., turn-taking rules
Last Last Time
• What is Cognitive Science?• What is Artificial Intelligence?
– Knowledge Representation• Languages
– Representing Common Sense• Common Sense Interfaces
•Story Understanding, Story Generation, and Common Sense
Today: Information Extraction• A short history: AI Story Understanding,
SAM, and FRUMP
• Basic Techniques: Lexical analysis, name recognition, syntax, scenario, coreference, inference, template
• Evaluation: MUC-3 to MUC-7
• What else can you do with an IE system? SpinDoctor and PLUM
History: Story Understanding
• Roger Schank and Robert Abelson, Scripts, Plans, Goals and Understanding, 1977
• Richard Cullingford, SAM, 1979
• Robert Wilensky, PAM, 1978
• Gerald DeJong, FRUMP, 1979
SAM: Script Applier Mechanism#| restaurant script: (1) go to the restaurant; (2) order a meal; (3)
eat the meal; (4) pay; (5) leave the restaurant |#(events-script '$restaurant '((ptrans (actor ?diner) (object ?diner) (to ?restaurant)) (mtrans (actor ?diner) (object (ingest (actor ?diner) (object ?meal)))) (ingest (actor ?diner) (object ?meal)) (atrans (actor ?diner) (object (money)) (from ?diner) (to ?restaurant)) (ptrans (actor ?diner) (object ?diner) (from ?restaurant) (to ?elsewhere))))
PAM: Plan and Goal Applier Mechanism?#| restaurant plan: goal: you’re hungry and you want to
eat; plan: go to a restaurant |#(goal (planner ?x)
(objective (is (actor ?x) (state (hunger (val 0))))(do-restaurant-plan (planner ?x) (restaurant ?y)))
(subgoal (do-restaurant-plan (planner ?x) (restaurant ?y)(goal (planner ?x)
(objective (proximity (actor ?x) (location ?y)))
(isa restaurant ?y)))
FRUMP: Fast Reading Understanding and Memory Program
$demonstration script• The demonstrators arrive at the
demonstration location.• The demonstrators march.• Police arrive on the scene.• The demonstrators communicate with the
target of the demonstration.• The demonstrators attack the target of the
demonstration.• The demonstrators attack the police.
(From DeJong, 1979; pp. 19-20)
Information Extraction: Basic Techniques
• Lexical analysis
• Name recognition
• Syntax
• Scenario
• Coreference
• Inference
• Template
Levels of Linguistic Analysis
• Sentences– Phonological/Morphological analysis– Syntactic analysis– Semantic analysis
• More than one sentence– Pragmatic analysis
Lexical Analysis• Input: Sam Schwartz retired as executive vice
president of the famous hot dog manufacturer, Hupplewhite Inc. He will be succeeded by Harry Himmelfarb.
• Output: – Sam/name Schwartz/name retired/verb as/prep
executive/adj vice/adj president/noun of/prep the/det famous/adj hot/adj dog/noun manufacturer/noun ,/comma Hupplewhite/name Inc/name ./period<end of sentence>
– He/pron will/verb be/verb succeeded/verb by/prep Harry/name Himmelfarb/name ./period <end of sentence>