Building Text Meaning Representations from Contextually Related Frames – A Case Study – Aljoscha Burchardt Anette Frank Manfred Pinkal Saarland University and DFKI Saarbrücken

Motivation  Broad-coverage statistical parsing systems –High demand for more „semantics-based“ processing  Deep computational semantic processing –Well-studied formalisms for truth-conditional and discourse semantics –Large-scale deep semantic parsing (e.g., Bos et al., 2004) –Little emphasis on lexical semantics and concept-based analysis  Lexical semantic resources –WordNet(s) used for approximate concept-based analysis –Lexical semantics resources that model predicate-argument structure (e.g. FrameNet, PropBank) –Automatic semantic role labelling (ConLL, Senseval)  Aim: Building partial text meaning representations from frame-annotated deep syntactic structures

Overview Frame Semantics for Partial Text Meaning Representation  Background: FrameNet „as a Net“  Building text meaning representations from frame semantic annotations A case study Linking of contextually related frames and frame roles –Based on patterns of lexico-semantic and contextual relations Generalisation and acquisition of linking patterns  Towards Automation: current architecture  Conclusion

FrameNet  Frame Semantics (Fillmore 1976, 1977,..) –Frame: a conceptual structure or prototypical situation –Frame elements (roles) Identify participants of the situation Are local to their frame –Frame evoking elements (verbs, nouns, adjectives) introduce frames –E.g. VERDICT: [The jury] Judge convicted [him] Defentant [on the counts of theft] Charges. On Thursday [a jury] Judge found [the youth] Defendant [guilty of wounding Mr Lay] Finding  Berkeley FrameNet Project –Database of frames for core lexicon of English –Current release: 610 frames, about 9000 lexical units

FrameNet „as a Net“ – Frame-to-Frame Relations – Inheritance relation: a frame inherits all roles of one or more “super” frame(s) PatientAgent ChargesOffense AuthoritiesSuspect Intentionally_act Arrest

FrameNet „as a Net“ – Frame-to-Frame Relations – Subframe relation –Super frame represents complex event –Subframes represent sub-events –Subframes usually inherit some roles of the super frame Criminal process ArraignmentArrestSentencingTrial Charge Judge Defendant Defense Court Jury Offense Prosecution Charge Defendant...

Frame Semantics for Partial Text Meaning Representation  Probabilistic models for semantic role labeling (Gildea & Jurafsky, 2002)  Frame semantic projection from deep (LFG) grammar (Frank & Erk, 2003) –No constructional “glue” –Partially connected/embedded lexico-semantic predicate- argument structures –Coarse-grained semantic structures  Challenge: obtain a more densely connected representation –By learning and applying heuristic linking patterns

A Case Study In the first trial in the world in connection with the terrorist attacks of 11 September 2001, the Higher Regional Court of Hamburg has passed down the maximum sentence. Mounir al Motassadeq will spend 15 years in prison. The 28-year-old Moroccan was found guilty as an accessory to murder in more than 3000 cases.

Local Roles In the first trial in the world in connection with [the [terrorist] Assailant attacks of [11 September 2001] Time ] Case, [the Higher Regional Court of Hamburg] Court has passed down the [maximum] Type sentence.

Local Roles [Mounir al Motassadeq] Inmates will spend [15 years] Duration in prison.

Local Roles [The 28-year-old Moroccan] Defendant was found [guilty] Finding as [an accessory to [murder] FocalEntity [in more than 3000 cases] Victim ] Charge.

Unfilled Roles TargetFrameFrame rolesFiller (given vs. Induced) trial TRIAL CASE terrorist attacks(1) CHARGE accessory to murder(2) COURT Higher Regional Court (3) DEFENDANT...28-year-old Moroccan(4) attacks ATTACK ASSAILANT terrorist(5) VICTIM...(6) TIME (exth.)11 September 2001(7) sentence SENTENCING CONVICT Mounir al Motassadeq(8) COURT Higher Regional Court(9) TYPE...maximum sentence(10) prison PRISON INMATES...Mounir al Motassadeq(11) DURATION (exth.) 15 years(12) found VERDICT CASE terrorist attacks(13) CHARGE accessory to murder(14) DEFENDANT 28-year-old Moroccan(15) FINDING...guilty(16) accessoryASSISTANCE CO-AGENT (17) FOCAL_ENTITY murder(18) HELPER...28-year-old Moroccan(19) murder KILLING KILLER (20) VICTIM...m.t cases(21)

Frames in Context TargetFrameFrame rolesFiller (given vs. Induced) trial TRIAL CASE terrorist attacks(1) CHARGE accessory to murder(2) COURT Higher Regional Court (3) DEFENDANT...28-year-old Moroccan(4) attacks ATTACK ASSAILANT terrorist(5) VICTIM...(6) TIME (exth.)11 September 2001(7) sentence SENTENCING CONVICT Mounir al Motassadeq(8) COURT Higher Regional Court(9) TYPE...maximum sentence(10) prison PRISON INMATES...Mounir al Motassadeq(11) DURATION (exth.) 15 years(12) found VERDICT CASE terrorist attacks(13) CHARGE accessory to murder(14) DEFENDANT 28-year-old Moroccan(15) FINDING...guilty(16) accessoryASSISTANCE CO-AGENT (17) FOCAL_ENTITY murder(18) HELPER...28-year-old Moroccan(19) murder KILLING KILLER (20) VICTIM...m.t cases(21)

Frames in Context TargetFrameFrame rolesFiller (given vs. Induced) trial TRIAL CASE terrorist attacks(1) CHARGE accessory to murder(2) COURT Higher Regional Court (3) DEFENDANT...28-year-old Moroccan(4) attacks ATTACK ASSAILANT terrorist(5) VICTIM...(6) TIME (exth.)11 September 2001(7) sentence SENTENCING CONVICT Mounir al Motassadeq(8) COURT Higher Regional Court(9) TYPE...maximum sentence(10) prison PRISON INMATES...Mounir al Motassadeq(11) DURATION (exth.) 15 years(12) found VERDICT CASE terrorist attacks(13) CHARGE accessory to murder(14) DEFENDANT 28-year-old Moroccan(15) FINDING...guilty(16) accessoryASSISTANCE CO-AGENT (17) FOCAL_ENTITY murder(18) HELPER...28-year-old Moroccan(19) murder KILLING KILLER (20) VICTIM...m.t cases(21)

Linking Frames and Roles in Context  At the instance level –given frame instances f 1 :F 1 and f 2 :F 2, where f 1 and f 2 stand in a contextual relation (syn, sem, discourse) frame types F 1 and F 2 stand in some frame relation => identify role instances (referents) of f 1 and f 2 (r 1 (= r 0 ) = r 2 ) frame relation context-related instances inferred relation

Linking Frames and Roles in Context In the first trial in the world in connection with the terrorist attacks of 11 September 2001, the Higher Regional Court of Hamburg has passed down the maximum sentence. Criminal Process Trial Sentencing Court frame relation

Linking Frames and Roles in Context In the first trial (f 1 ) in the world in connection with the terrorist attacks of 11 September 2001, [the Higher Regional Court of Hamburg] (r 2 ) has passed down the maximum sentence (f 2 ). The Higher Regional Court of Hamburg Functional Embedding Criminal Process Trial Sentencing Court frame relation context-related instances

Linking Frames and Roles in Context The Higher Regional Court of Hamburg Functional Embedding Criminal Process Trial Sentencing Court frame relationcontext-related instancesinferred relation In the first trial (f 1 ) in the world in connection with the terrorist attacks of 11 September 2001, [the Higher Regional Court of Hamburg] (r 2 =r 0 = r 1 ) has passed down the maximum sentence (f 2 ).

Linking Frames and Roles in Context  At the type level (more involved) –If instances of frame roles f 1 :F 1 and f 2 :F 2 are often found co- referent within particular contextual relations => Hypothesize a frame relation between F 1 and F 2 (no) frame relation context-related instances inferred relation

Linking Frames and Roles in Context (no) frame relation context-related instances inferred relations … the Higher Regional Court of Hamburg has passed down the Maximum sentence. [Mounir al Motassadeq] will spend 15 years in prison. Sentencing Prison Convict Inmates Discourse Relation New Frame Relation (Role Binding: Convict=Inmates) (Co-reference)

Meaning Postulates („Semantic Control“)  Example: the Defendant in a VERDICT is the actor of the Frame embedded in the VERDICT Charge role („Charge event“)  Modeled as „Semantic Control“: –VERDICT embeds some frame Fx under role Charge, –Fx.Rx inherits from INTENT._ACT.AGENT => VERDICT.Defendant equals Fx.Rx (at the type level) VERDICT Fx INTENT._ ACT Agent Rx Charge Defendant Semantic Control „[...Moroccan] DEF was found guilty as an accessory (Fx) to murder“ => VERDICT.Defendant equals ASSISTANCE.Helper

Generalisation  Selected deeper semantic represention to model –referential properties (introduction of new discourse referents) => blocking factors for role identification rules –Temporal sequence and locational properties => deeper contextual semantic relations between frames Mounir El Motassadeq (born April 3, 1974) is a Moroccan. In February 2003 he was convicted [...]. As of April 2004 he is the only person to have been convicted in direct relation to the September 11, 2001 attacks. The verdict and sentence were set aside on appeal [...]. A new trial is expected in mid-2004.

Acquisition of Linking Patterns  Identified patterns for induction of role-linking –Lexico-semantic relations Subframe and Inheritance relation, Semantic Control –Contextual relations Syntactic and semantic embedding Anaphoricity and referential properties Discourse relations (or surface linearisation)  Future work –Learning weighted role-linking patterns from annotated texts in restricted domains, to be used as probabilistic inference rules –“[Baragiola] CONVICT / ESCAPEE had previously been convicted of murder in Italy, but had escaped in 1980 and obtained Swiss citizenship.” => Infer PRISON and PRISON.Inmates = ESCAPE.Escapee

Current Architecture  LFG-based parsing and syntax-semantics interface –ParGram grammars for German and English (Butt et al. 2002) –Frame projection from f-structure (XLE transfer system) –Interfaces to statistical frame assignment (Baldewein et al. 2004)  Enriching Semantic Representation –Rule-based refinement of semantic representation –Autom. assignment of SUMO/MILO classes (using WordNet WSD)  Logical Representation and Reasoning –Frame relations translated to logic programs –Joint work with P. Baumgartner and F. Suchanek, MPI Saarbrücken –First scenario: RTE Challenge

Conclusion  Combining –Deep syntactic analysis and Frame Semantic role assignments  Methods –Linking partial frame annotations in context –Generalisation and automation  Shallow semantic representations –Necessarily partial (focusing on open class categories) –Robust semantic processing for coarse-grained information access –Incremental depth for finer-grained analysis

Frame Exchange Format „fef“

Types of Relations  FrameNet Relations –Frame hierarchy: inherits –Subframes  Contextual Relations between instantiated frames and roles –Syntactic and/or semantic embedding –Discourse relations –Anaphoric relations  Inferences –On the basis of both

CRIMINAL PROCESS SENTENCING (1)TRIAL (1) VERDICT (3) Defendant KILLING (3) Inferred Relation Contextual Relation Killer Subframe/FE PRISON (2) InmatesDuration ASSISTANCE (3) HelperCo_agentFocal_entityVictim ConvictType Court CaseCharge CaseCharge Court Finding (1)sentence number Frame, Contextual, and Inferred Relations

CRIMINAL PROCESS SENTENCINGTRIAL VERDICT Defendant (the Moroccan) KILLING Inference Contextual Relations Killer Hierarchy/Subframe/FE PRISON Inmates (Motus.) Duration (15Y) ASSISTANCE HelperCo_agentGoal (murder) Victim (3000) ConvictDuration (maximum) Court (Hmbg.) Case (9/11) Charge CaseCharge (accessory) In the first trial.. the higher Regional Court.. has passed down the maximum sentence. Mounir al Motussadeq will spend 15 years in prison. The 28-year-old Moroccan was found guilty as an accessory to murder in cases.

More Involved Examples Semantic control A meaning relation between frame roles F2:R2 and Fx:Rx –where F2 embeds Fx (via some role R3), and –F2:R2 semantically controls (is co-referent with) the AGENT role Fx:Rx of Fx frame relation context-related instances inferred relation

More Involved Examples Semantic control Example: „... was found guilty as an accessory to murder“ VERDICT foundCASE terrorist attacks(13) CHARGE accessory to murder(14) DEFENDANT 28-year-old Moroccan(15) FINDING...guilty(16) INTENTIONALLY_ACTAGENT ASSISTANCE accessoryCO-AGENT (17) FOCAL_ENTITY murder(18) HELPER...28-year-old Moroccan(19) frame relation context-related instances inferred relation

More Involved Examples (?)  Semantic Control – „... was found guilty as an accessory to murder“ The CO-AGENT of ASSISTANCE is co-referent with the AGENT of the frame embedded under ASSISTANCE.FOCAL_ENTITY => ASSISTANCE.CO-AGENT coreferent with KILLING.KILLER –SENTENCING.CONVICT co-referent with PRISON.INMATES CAUSATION.CAUSE embeds SENTENCING CAUSATION.EFFECT embeds PRISON PATIENT(CAUSATION.CAUSE) co-referent with PATIENT(CAUSATION.EFFECT) (semantic control) (where PATIENT(Frame) inherits from INTENTIONALLY_AFFECT.PATIENT) PATIENT(SENTENCING) = SENTENCING.CONVICT => PATIENT(PRISON) = PRISON.INMATES