building text meaning representations from contextually related frames – a case study – aljoscha...

Building Text Meaning Representations from Contextually Related Frames

– A Case Study –

Aljoscha BurchardtAnette Frank

Manfred Pinkal

Saarland University and DFKISaarbrücken

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

Authorities Suspect

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

Criminalprocess

Arraignment Arrest Sentencing Trial

Charge

JudgeDefendant

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

Target Frame Frame roles Filler (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)

accessory ASSISTANCE CO-AGENT (17)FOCAL_ENTITY murder (18)HELPER ... 28-year-old Moroccan (19)

murder KILLING KILLER (20)VICTIM ... m.t. 3000 cases (21)

Frames in Context



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)






Frames in Context



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)






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)

frame relation context-related instances inferred relation


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

SentencingCourt

frame relation


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).

The Higher Regional Court of Hamburg

Functional Embedding

Criminal Process

Trial

SentencingCourt

frame relation context-related instances


The Higher Regional Court of Hamburg

Functional Embedding

Criminal Process

Trial

SentencingCourt


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).


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

(no) frame relation context-related instances inferred relation


(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

ChargeDefendant

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 2004he is the only person to have been convicted in direct relationto the September 11, 2001 attacks. The verdict and sentencewere set aside on appeal [...]. A new trial is expectedin 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

Defendant

KILLING (3)

Inferred RelationContextual Relation Killer

Subframe/FE

PRISON (2)

Inmates Duration

ASSISTANCE (3)

Helper Co_agentFocal_entityVictim

Convict Type Court CaseCharge

CaseCharge

Court

Finding

(1) sentence number

Frame, Contextual, and Inferred Relations

CRIMINAL PROCESS

SENTENCING TRIAL

VERDICT

Defendant

Defendant(the Moroccan)

KILLING

InferenceContextual Relations

Killer

Hierarchy/Subframe/FE

PRISON

Inmates(Motus.)

Duration(15Y)

ASSISTANCE

Helper Co_agentGoal(murder)

Victim(3000)

Convict Duration(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 .. 3000 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


More Involved Examples

Semantic control

Example: „... was found guilty as an accessory to murder“

VERDICT found CASE terrorist attacks (13) CHARGE accessory to murder (14)


INTENTIONALLY_ACT AGENT

ASSISTANCE accessory CO-AGENT (17)FOCAL_ENTITY murder (18)HELPER ... 28-year-old Moroccan (19)


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 PRISONPATIENT(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

building text meaning representations from contextually related frames – a case study – aljoscha...

Documents

frame frame

frame roles

frame semantic projection

frame semantic annotations

overview frame semantics

related frames

dfki saarbrcken slide

act arrest slide