@article {5370,
title = {Formalization and logical properties of the Maximal Ideal Recursive Semantics for Weighted Defeasible Logic Programming},
journal = {Journal of Experimental \& Theoretical Artificial Intelligence},
volume = {28},
year = {2016},
pages = {275-294},
abstract = {Possibilistic Defeasible Logic Programming (P-DeLP) is a logic programming framework which com- bines features from argumentation theory and logic programming, in which defeasible rules are attached with weights expressing their relative belief or preference strength. In P-DeLP a conclusion succeeds if there exists an argument that entails the conclusion and this argument is found to be undefeated by a war- rant procedure that systematically explores the universe of arguments in order to present an exhaustive synthesis of the relevant chains of pros and cons for the given conclusion. Recently, we have proposed a new warrant recursive semantics for P-DeLP, called Recursive P-DeLP (RP-DeLP for short), based on the claim that the acceptance of an argument should imply also the acceptance of all its subarguments which reflect the different premises on which the argument is based. This paper explores the relationship between the exhaustive dialectical analysis based semantics of P-DeLP and the recursive based semantics of RP-DeLP, and analyzes a non-monotonic inference operator for RP-DeLP which models the expansion of a given program by adding new weighted facts associated with warranted conclusions. Given the recursive based semantics of RP-DeLP, we have also implemented an argumentation frame- work for RP-DeLP that is able to compute not only the output of warranted and blocked conclusions, but also explain the reasons behind the status of each conclusion. We have developed this framework as a stand-alone application with a simple text-based input/output interface to be able to use it as part of other AI systems.},
url = {http://www.tandfonline.com/doi/full/10.1080/0952813X.2015.1024490}
}
@article {5069,
title = {RP-DeLP: A weighted defeasible argumentation framework based on a recursive semantics},
journal = {Journal of Logic and Computation},
volume = {26},
year = {2016},
pages = {1315-1360},
abstract = {In this paper we propose a recursive semantics for warranted formulas in a general defeasible logic argumentation framework by formalizing a notion of collective (non-binary) conflict among arguments. The recursive semantics for warranted formulas is based on the intuitive grounds that if an argument is rejected, then further arguments built on top of it should also be rejected. The main characteristic of our recursive semantics is that an output (or extension) of a knowledge base is a pair consisting of a set of warranted and a set of blocked formulas. Arguments for both warranted and blocked formulas are recursively based on warranted formulas but, while warranted formulas do not generate any collective conflict, blocked conclusions do. Formulas that are neither warranted nor blocked correspond to rejected formulas. Then we extend the framework by attaching levels of preference to defeasible knowledge items and by providing a level-wise definition of warranted and blocked formulas. After we consider the warrant recursive semantics for the particular framework of Possibilistic Defeasible Logic Programming (RP-DeLP for short). Since RP-DeLP programs may have multiple outputs, we define the maximal ideal output of an RP-DeLP program as the set of conclusions which are ultimately warranted, and we present an algorithm for computing it in polynomial space and with an upper bound on complexity equal to P^NP . Finally, we propose an efficient and scalable implementation of this algorithm using SAT encodings, and we provide an experimental evaluation when solving test sets of instances with single and multiple preference levels for defeasible knowledge.},
url = {http://logcom.oxfordjournals.org/content/early/2014/02/14/logcom.exu008.short?rss=1}
}
@conference {5320,
title = {On the Characterization of the Maximal Ideal Recursive Semantics of RP-DeLP},
booktitle = {CCIA 2014},
volume = {269},
year = {2014},
month = {22/10/2014},
pages = {215 - 224},
publisher = {IOS Press},
organization = {IOS Press},
edition = {L. Museros, O. Pujol, N. Agell},
address = {Barcelona},
abstract = {Possibilistic Defeasible Logic Programming (P-DeLP) is a logic pro- gramming framework which combines features from argumentation theory and logic programming, in which defeasible rules are attached with weights express- ing their relative belief or preference strength. In P-DeLP a conclusion succeeds if there exists an argument that entails the conclusion and this argument is found to be undefeated by a warrant procedure that systematically explores the universe of arguments in order to present an exhaustive synthesis of the relevant chains of pros and cons for the given conclusion. Recently, we have proposed a new warrant recur- sive semantics for P-DeLP, called Recursive P-DeLP (RP-DeLP for short), based on the claim that the acceptance of an argument should imply also the acceptance of all its subarguments which reflect the different premises on which the argument is based. In RP-DeLP, an output of a program is a pair of sets, a set of warranted and a set of blocked conclusions.Arguments for both warranted and blocked conclusions are recursively based on warranted conclusions but, while warranted conclusions do not generate any conflict with the set of already warranted conclusions and the strict part of program (information we take for granted they hold true), blocked conclusions do. Conclusions that are neither warranted nor blocked correspond to rejected conclusions. This paper explores the relationship between the exhaustive dialectical analysis based semantics of P-DeLP and the recursive based semantics of RP-DeLP and analyzes a non-monotonic operator for RP-DeLP which models the expansion of a given program by adding new weighed facts associated with warranted conclusions.},
url = {http://ebooks.iospress.nl/volumearticle/38068},
author = {Teresa Alsinet and Ramon Bejar and Llu{\'\i}s Godo and Francesc Guitart}
}
@conference {5026,
title = {On the Implementation of a Multiple Output Algorithm for Defeasible Argumentation},
booktitle = {7th International Conference on Scalable Uncertainty Management, SUM 2013},
volume = {8078},
year = {2013},
month = {16/09/2013},
pages = {71-77},
publisher = {Springer},
organization = {Springer},
edition = {W. Liu, V. S. Subrahmanian and J. Wijsen},
address = {Washington DC, USA},
abstract = {In a previous work we defined a recursive warrant semantics for Defeasible Logic Programming based on a general notion of collective conflict among arguments. The main feature of this recursive semantics is that an output of a program is a pair consisting of a set of warranted and a set of blocked formulas. A program may have multiple outputs in case of circular definitions of conflicts among arguments. In this paper we design an algorithm for computing each output and we provide an experimental evaluation of the algorithm based on two SAT encodings defined for the two main combinatorial subproblems that arise when computing warranted and blocked conclusions for each output.},
isbn = {978-3-642-40380-4},
url = {http://link.springer.com/chapter/10.1007\%2F978-3-642-40381-1_6},
author = {Teresa Alsinet and Ramon Bejar and Llu{\'\i}s Godo and Francesc Guitart}
}
@conference {5027,
title = {Web Based System for Weighted Defeasible Argumentation},
booktitle = {14th International Workshop on Computational Logic in Multi-Agent Systems, CLIMA XIV},
volume = {8143},
year = {2013},
month = {16/09/2013},
pages = {155-171},
publisher = {Springer},
organization = {Springer},
edition = {J. Leite, T. C. Son, P. Torroni, L. van der Torre and S. Woltran},
address = {A Coru{\~n}a, Spain},
abstract = {In a previous work we defined a recursive semantics for reasoning about which arguments should be warranted when extending Defeasible Argumentation with defeasibility levels for arguments. Our approach is based on a general notion of collective conflict among arguments and on the fact that if an argument is warranted it must be that all its sub-arguments also are warranted. An output of a program is a pair consisting of a set of warranted and a set of blocked arguments with maximum strength. Arguments that are neither warranted nor blocked correspond to rejected arguments. On this recursive semantics a program may have multiple outputs in case of circular definitions of conflicts among arguments and for these circular definitions of conflicts we define what output, called maximal ideal output, should be considered based on the claim that if an argument is excluded from an output, then all the arguments built on top of it should also be excluded from that output. In this paper we show a web based system we have designed and implemented to compute the output for programs with single and multiple outputs. For programs with multiple outputs the system also computes the maximal ideal output. An interesting feature of the system is that it provides not only both sets of warranted an blocked arguments with maximum strength but also useful information that allows to better understand why an argument is either warranted, blocked or rejected.},
isbn = {978-3-642-40623-2},
url = {http://link.springer.com/chapter/10.1007\%2F978-3-642-40624-9_10},
author = {Teresa Alsinet and Ramon Bejar and Llu{\'\i}s Godo and Francesc Guitart}
}
@conference {4806,
title = {Using Answer Set Programming for an scalable implementation of Defeasible Argumentation},
booktitle = {24th IEEE International Conference on Tools with Artificial Intelligence (ICTAI 2012)},
volume = {1},
year = {2012},
month = {07/11/2012},
pages = {1016-1021},
publisher = {IEEE Conference Publishing Services},
organization = {IEEE Conference Publishing Services},
address = {Athens (Greece)},
abstract = {Recently, a recursive warrant semantics for Defeasible Logic Programming extended with levels of possibilistic uncertainty for defeasible rules was introduced. The resulting argumentation framework, called RP-DeLP, is based on a general notion of collective (non-binary) conflict among arguments allowing to ensure direct and indirect consistency properties with respect to the strict knowledge. In this paper we propose an efficient and scalable implementation of an interpreter for RP-DeLP using Answer Set Programming (ASP) encodings for the two main queries of the system: looking for valid arguments and finding collective conflicts among arguments. We perform an experimental evaluation of our ASP approach and we compare the results with a previously proposed SAT based approach. The results show that with ASP we are able to scale up to bigger problem instances.},
isbn = {978-1-4799-0227-9},
url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6495159},
author = {Teresa Alsinet and Ramon Bejar and Llu{\'\i}s Godo and Francesc Guitart}
}
@conference {4347,
title = {Maximal Ideal Recursive Semantics for Defeasible Argumentation},
booktitle = {SUM 2011},
volume = {6929},
year = {2011},
month = {10/10/2011},
pages = {96-109},
publisher = {Springer-Verlag},
organization = {Springer-Verlag},
address = {Dayton (Ohio), USA},
keywords = {Defeasible argumentation, maximal ideal output, recursive warrant semantics},
author = {Teresa Alsinet and Ramon Bejar and Llu{\'\i}s Godo and Francesc Guitart},
editor = {S. Benferhat, J. Grant}
}