Cerutti--ECSQARU 2009

transcript

University of BresciaDipartimento di Elettronica per l'Automazione

Knowledge Engineering and Human-Computer Interaction Research Group

Encompassing Attacks to Encompassing Attacks to Attacks in Abstract Attacks in Abstract

Argumentation FrameworksArgumentation Frameworks

Pietro Baroni, Federico Cerutti, Massimiliano Giacomin and Giovanni GuidaPietro Baroni, Federico Cerutti, Massimiliano Giacomin and Giovanni Guida

Summary

Introduction by example Formalization Relationship with Dung's Argumentation Framework Comparison with other approaches Conclusion and future works

Introduction by exampleIntroduction by example➢ Formalization

➢ Relationship with Dung's Argumentation Framework➢ Comparison with other approaches

➢ Conclusion and future works

Example (1)

Simple decision support problem Bob's holidays plan Two possible choices:

Gstaad Cuba

Preferences among the possible choices Exception to the preference's general rule

Example (2)

There is a last minute offer for Gstaad →

I should go to Gstaad

If I go to Cuba, I can notgo to Gstaad

There is a last minute offer for Cuba →

I should go to Cuba

Example (3)

When it is possible, I preferto go to a ski resort

According to this preference, the possible choice for Cuba can

not attack the one for Gstaad

Example (4)

The preference aboutskiing does not apply

in the current situation

Since there were no snowfalls inGstaad since a month, it is notpossible to go to ski in Gstaad.

Example (5)

It is possible to ski in Gstaadthanks to artificial snow

FormalizationFormalization➢ Introduction by example

Argumentation Framework withRecoursive Attacks (AFRA)

Formalization of the example (1)

Defeat relation

Admissibility

Fundamental lemma and preferred extension

Relationship with Dung's Relationship with Dung's Argumentation FrameworkArgumentation Framework

➢ Introduction by example➢ Formalization

➢ Comparison with other approaches➢ Conclusion and future works

Correspondence between AFRA and AF (1)

Correspondence in the example

Correspondence between AFRA and AF (2)

Correspondence in the example:The Preferred Extension

Comparison with other Comparison with other approachesapproaches

➢ Relationship with Dung's Argumentation Framework

Argumentation attack model

Modelling the strength of nodes and attacks with propagation

Argumentation attack model [Barringer et al, 2005] Recursive definition of “torpedoes”, or attacks,

similarly as AFRA attacks Focus on attack network and its numerical valuation Dung style semantics issues not considered

The EAF formalism

Reasoning about preferences/values can be formalized through attacks to attacks

Extended Argumentation Framework [Modgil, 2007;2009]

Specific assumptions: A limited level of recursion A constraint on some attacks to be symmetric (when the

involved arguments represent conflicting preferences)

In the paper we have considered a possible extension of EAF aimed at overcoming these restrictions

Higher-order AF

Reasoning about coalitions Model of attacks to attacks as an instance of Dung's

Argumentation Framework Proposal of a “second order argumentation

framework” with some constraints like EAF Proposal of a “higher order argumentation

framework” without such constraints [Boella et al, 2009]

Conclusion and future Conclusion and future worksworks

Conclusion and future works

Preliminary investigation about AFRA Generalization of Dung's Argumentation Framework Attacks to attacks recursively encompassed without

restriction Focus on decision support context Future works:

Enlarging the theoretical bases of AFRA Investigating the definition of argumentation semantics in

this context

Cerutti--ECSQARU 2009

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