FATE: a FrameNet Annotated corpus for Textual Entailment Marco Pennacchiotti, Aljoscha Burchardt Computerlinguistik Saarland University, Germany LREC 2008, Marrakech, 28 May 2008 SALSA II - The Saarbrücken Lexical Semantics Acquisition Project

Summary FrameNet and Textual Entailment FATE annotation schema Annotation examples and statistics Conclusions 28/05/20082 / 17FATE - Marco Pennacchiotti

Frame Semantics Frame: conceptual structure modeling a prototypical situation Frame Elements (FE): participants of the situation Frame Evoking elements (FEE): predicates evoking the situation [Fillmore 1976, 2003] 28/05/20083 / 17FATE - Marco Pennacchiotti Predicate-argument level normalizations FrameNet Berkeley Project 1 – Database of frames for the core lexicon of English – 800 frames, lemmas, annotated sentences (1) “Evelyn spoke about her past” “Evelyn’s statement about her past” STATEMENT( S PEAKER : Evelyn; T OPIC : her past )

Textual Entailment (TE) Given two text fragments, the Text T and the Hypothesis H, T entails H if the meaning of H can be inferred from the meaning of T, as would typically interpreted by people [Dagan 2005] Given two text fragments, the Text T and the Hypothesis H, T entails H if the meaning of H can be inferred from the meaning of T, as would typically interpreted by people [Dagan 2005] T: “Yahoo has recently acquired Overture” H: “Yahoo owns Overture” T  H Recognizing Textual Entailment (RTE) – recognize if entailment holds for a given (T,H) pair – Models core inferences of many NLP applications (QA, IE, MT,…) RTE Challenges [Dagan et al.,2005 ; Giampiccolo et al., 2007] – Compare systems for RTE – Corpus: 800 training pairs, 800 test pairs, evenly split in + and - pairs 28/05/20084 / 17FATE - Marco Pennacchiotti

Predicate-argument and RTE Predicate-level inference plays a relevant role in TE (20% of positive examples in RTE-2 [Garoufi, 2007] ) An avalanche has struck a popular skiing resort in Austria, killing at least 11 people. Humans died in an avalanche. Implementation gap : [Burchardt et al.,2007] : FrameNet system comparable to lexical overlap [Hickl et al.,2006] : PropBank-based features are not effective [Rana et al.,2005]: DIRT paraphrase repository does not help 28/05/20085 / 17FATE - Marco Pennacchiotti DEATH( P ROTAGONIST : 11 people / humans ; C AUSE : avalanche / avalanche )

FATE corpus Reference corpus: RTE-2 test set, 800 pairs, 29,000 tokens Frame resource : FrameNet version 1.3 Corpus Format : SALSA/TIGER XML [Burchardt et al.,2006] Pre-processing: annotation on top of Collins parser syntactic analysis : T and H are randomly reordered to avoid biases Annotation : performed by one highly experienced annotator : inter-annotator agreement over 5% of the corpus – FEE-agreement : 82% – Frame-agreement: 88% – Role-agreement: 91% : annotation carried out using the SALTO tool 1 (1) 28/05/20086 / 17FATE - Marco Pennacchiotti FATE: a manually frame-annotated Textual Entailment corpus, to study the role of frame semantics in RTE

FATE annotation process: an example 28/05/20087 / 17FATE - Marco Pennacchiotti Collins synt. an. full-text annotation (all words considered) [Ruppenhofer,2007]

FATE annotation process: an example 28/05/20088 / 17FATE - Marco Pennacchiotti frame FEE Collins synt. an.

FATE annotation process: an example 28/05/20089 / 17FATE - Marco Pennacchiotti frame FE Collins synt. an. FEE FE filler Maximization principle: chose the largest constituent possible when annotating

Annotation Schema Intuition: annotate as FEE only those words evoking a relevant situation (frame) in the sentence at hand – Very intuitive flavor, but high agreement: 83% on a pilot set of 15 sentences Relevance Principle “Authorities in Brazil hold 200 people as hostage” LEADERSHIPDETAINPEOPLE KIDNAPPING 28/05/ / 17FATE - Marco Pennacchiotti V ICTIM P LACE P ERPETRATOR

Annotation Schema On T of positive pairs, annotate only the fragments (spans) contributing to the inferential process – Spans are obtained from the ARTE annotation [Garoufi,2007] – For negative pairs it is not straightforward to derive spans, hence we do full annotation Span Annotation T: “Soon after the EZLN had returned to Chiapas, Congress approved a different version of the COCOPA Law, which did not include the autonomy clauses, claiming they were in contradiction with some constitutional rights (private property and secret voting); this was seen as a betrayal by the EZLN and other political groups.” H: “EZLN is a political group.” 28/05/ / 17FATE - Marco Pennacchiotti

Annotation Schema Unknown frames: use an U NKNOWN frame for words evoking situations not present in the FrameNet database Anaphora Copula and support verbs Modal expressions Metaphors Existential constructions … Other guidelines 28/05/ / 17FATE - Marco Pennacchiotti

Corpus statistics Annotated pairs : 800 (400 positive, 400 negatives) Annotated frames : 4,500 : avg. 5.6 frames per pair : 1,600 frames in positive pairs : 2,800 in negative pairs Annotated roles : 9,500 :avg. 2.1 roles per frame Annotation time: 230 hours : 90 h for positive pairs (13 min/pair) : 140 h for negative pairs (21 min/pair) 28/05/ / 17FATE - Marco Pennacchiotti

FrameNet and RTE (simple case) 28/05/ / 17FATE - Marco Pennacchiotti Syntactic normalization – Active / Passive EDUCATIONAL_TEACHING( S TUDENT : ground soldiers / soldiers; M ATERIAL : virtual reality/ virtual reality )

(1)Resource coverage is too low (2)Models for predicate-argument inference are weak (3)Automatic annotation models (SRL) are not good enough to be safely used in RTE Implementation gap insights 28/05/ / 17FATE - Marco Pennacchiotti FrameNet coverage is good: – 373 Unknown frames (8 % of total frames) – Unknown roles 1 % of total roles Coverage is unlikely to be a limiting factor for using FrameNet in applications

(1)Resource coverage is too low (2)Models for predicate-argument inference are weak (3)Automatic annotation models (SRL) are not good enough to be safely used in RTE 28/05/ / 17FATE - Marco Pennacchiotti To better study predicate-argument inference in RTE To experiment frame-RTE models on a gold-std corpus To learn better SRL models, by training on FATE Corpus is freely available on-line Why should you use FATE ?

Thank you! Questions? 28/03/2008FATE – Marco Pennacchiotti17 / 17 FATE download: