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Building Text Meaning Representations from Contextually Related Frames – A Case Study –

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

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Building Text Meaning Representations from Contextually Related Frames – A Case Study –

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

  2. 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

  3. 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

  4. FrameNet • Frame Semantics(Fillmore 1976, 1977, ..) • Frame: a conceptual structure or prototypical situation • Frame elements (roles) • Identify participantsof the situation • Are local to their frame • Frame evoking elements (verbs, nouns, adjectives) introduce frames • E.g. VERDICT: [The jury]Judgeconvicted [him]Defentant [on the counts of theft]Charges. On Thursday [a jury]Judgefound [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

  5. FrameNet „as a Net“–Frame-to-Frame Relations – Inheritance relation: a frame inherits all roles of one or more “super” frame(s) Intentionally_act Agent Patient Arrest Authorities Suspect Offense Charges

  6. Defense Judge Defendant Jury Court Offense Charge Prosecution Defendant Charge ... ... ... ... 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 Arraignment Arrest Sentencing Trial

  7. 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

  8. 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.

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

  10. Local Roles [Mounir al Motassadeq]Inmates will spend [15 years]Durationin prison.

  11. 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.

  12. Unfilled Roles Target Frame Frame roles Filler (given vs. Induced) trialTRIAL CASE terrorist attacks (1) CHARGE accessory to murder(2) COURT Higher Regional Court (3) DEFENDANT ...28-year-old Moroccan (4) attacksATTACK ASSAILANT terrorist (5) VICTIM ... (6)TIME (exth.) 11 September 2001 (7) sentenceSENTENCINGCONVICT Mounir al Motassadeq (8)COURT Higher Regional Court (9) TYPE ... maximum sentence (10) prisonPRISON INMATES ... Mounir al Motassadeq (11) DURATION (exth.) 15 years (12) foundVERDICT CASE terrorist attacks (13) CHARGE accessory to murder (14) DEFENDANT 28-year-old Moroccan (15) FINDING ... guilty (16) accessory ASSISTANCE CO-AGENT (17) FOCAL_ENTITY murder (18) HELPER ...28-year-old Moroccan (19) murderKILLING KILLER (20) VICTIM ... m.t. 3000 cases (21)

  13. Frames in Context Target Frame Frame roles Filler (given vs. Induced) trialTRIAL CASE terrorist attacks (1) CHARGE accessory to murder (2) COURT Higher Regional Court (3) DEFENDANT ... 28-year-old Moroccan (4) attacksATTACK ASSAILANT terrorist (5) VICTIM ... (6)TIME (exth.) 11 September 2001 (7) sentenceSENTENCING CONVICT Mounir al Motassadeq (8)COURT Higher Regional Court (9) TYPE ... maximum sentence (10) prisonPRISON INMATES ... Mounir al Motassadeq (11) DURATION (exth.) 15 years (12) foundVERDICT CASE terrorist attacks (13) CHARGE accessory to murder (14) DEFENDANT 28-year-old Moroccan (15) FINDING ... guilty (16) accessory ASSISTANCECO-AGENT(17) FOCAL_ENTITY murder (18) HELPER ...28-year-old Moroccan (19) murderKILLING KILLER (20) VICTIM ... m.t. 3000 cases (21)

  14. Frames in Context Target Frame Frame roles Filler (given vs. Induced) trialTRIAL CASE terrorist attacks (1) CHARGE accessory to murder (2) COURT Higher Regional Court (3) DEFENDANT ... 28-year-old Moroccan (4) attacksATTACK ASSAILANT terrorist (5) VICTIM ... (6)TIME (exth.) 11 September 2001 (7) sentenceSENTENCINGCONVICT Mounir al Motassadeq (8)COURT Higher Regional Court (9) TYPE ... maximum sentence (10) prisonPRISON INMATES ... Mounir al Motassadeq (11) DURATION (exth.) 15 years (12) foundVERDICT CASE terrorist attacks (13) CHARGE accessory to murder (14) DEFENDANT 28-year-old Moroccan (15) FINDING ... guilty (16) accessory ASSISTANCE CO-AGENT (17) FOCAL_ENTITY murder (18) HELPER ...28-year-old Moroccan (19) murderKILLING KILLER (20) VICTIM ... m.t. 3000 cases (21)

  15. Linking Frames and Roles in Context • At the instance level • given frame instances f1:F1 and f2:F2, where • f1 and f2 stand in a contextual relation (syn, sem, discourse) • frame types F1 and F2 stand in some frame relation => identify role instances (referents) of f1 and f2 (r1 (= r0) = r2) inferred relation frame relation context-related instances

  16. 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 Court Sentencing Trial frame relation

  17. Linking Frames and Roles in Context In the first trial (f1) in the world in connection with the terrorist attacks of 11 September 2001, [the Higher Regional Court of Hamburg] (r2) has passed down the maximum sentence (f2). Criminal Process Court Sentencing Functional Embedding Trial The Higher Regional Court of Hamburg frame relation context-related instances

  18. Linking Frames and Roles in Context In the first trial (f1) in the world in connection with the terrorist attacks of 11 September 2001, [the Higher Regional Court of Hamburg] (r2=r0= r1) has passed down the maximum sentence (f2). Criminal Process Court Sentencing Functional Embedding Trial The Higher Regional Court of Hamburg frame relation context-related instances inferred relation

  19. Linking Frames and Roles in Context • At the type level (more involved) • If instances of frame roles f1:F1 and f2:F2 are often found co-referent within particular contextual relations => Hypothesize a frame relation between F1 and F2 inferred relation (no) frame relation context-related instances

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

  21. 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 INTENT._ ACT „[...Moroccan]DEFwas found guilty as an accessory (Fx) to murder“ => VERDICT.Defendant equals ASSISTANCE.Helper Defendant Charge Agent Fx Semantic Control Rx

  22. Generalisation • Selected deeper semantic representionto 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.

  23. 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

  24. 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

  25. 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

  26. Frame Exchange Format „fef“

  27. 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

  28. Frame, Contextual, and Inferred Relations CRIMINAL PROCESS PRISON (2) SENTENCING (1) TRIAL (1) Inmates Duration Convict Type Defendant Charge Case Court Court VERDICT (3) Defendant Finding Charge Case ASSISTANCE (3) KILLING (3) (1) sentence number Subframe/FE Contextual Relation Victim Killer Helper Focal_entity Co_agent Inferred Relation

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

  30. 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 inferred relation frame relation context-related instances

  31. 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_ACT AGENT ASSISTANCE accessoryCO-AGENT (17) FOCAL_ENTITY murder (18) HELPER ...28-year-old Moroccan(19) inferred relation frame relation context-related instances

  32. 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

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