Massimiliano Giacomin

Massimiliano Giacomin
Università degli Studi di Brescia | UNIBS · Department of Information Engineering

About

102
Publications
10,334
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2,333
Citations
Citations since 2016
22 Research Items
1192 Citations
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2016201720182019202020212022050100150200
2016201720182019202020212022050100150200

Publications

Publications (102)
Chapter
Full-text available
We propose a generic notion of consistency in an abstract labelling setting, based on two relations: one of intolerance between the labelled elements and one of incompatibility between the labels assigned to them, thus allowing a spectrum of consistency requirements depending on the actual choice of these relations. As a first application to formal...
Preprint
The sixth assessment of the international panel on climate change (IPCC) states that "cumulative net CO2 emissions over the last decade (2010-2019) are about the same size as the 11 remaining carbon budget likely to limit warming to 1.5C (medium confidence)." Such reports directly feed the public discourse, but nuances such as the degree of belief...
Article
Full-text available
This paper aims at comparing and relating belief revision and argumentation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suitabl...
Chapter
The paper introduces a general model for the study of decomposability in abstract argumentation, i.e. the possibility of determining the semantics outcome based on local evaluations in subframeworks. As such, the paper extends a previous work by generalizing over the kind of information locally exploited. While not concerned with specific semantics...
Chapter
In this paper we introduce \(\textsf {AASExts}\), an algorithm for computing semi–stable extensions. We improve techniques developed for other semantics, notably preferred semantics, as well as leverage recent advances in All-SAT community. We prove our proposed algorithm is sound and complete, we describe the experiments to select the most appropr...
Article
In this paper we illustrate the design choices that led to the development of ArgSemSAT, the winner of the preferred semantics track at the 2017 International Competition on Computational Models of Arguments (ICCMA 2017), a biennial contest on problems associated to the Dung's model of abstract argumentation frameworks, widely recognised as a funda...
Article
In this paper, we describe how predictive models can be positively exploited in abstract argumentation. In particular, we present two main sets of results. On one side, we show that predictive models are effective for performing algorithm selection in order to determine which approach is better to enumerate the preferred extensions of a given argum...
Article
In the field of computational argumentation several formalisms featuring different levels of abstraction and focusing on different aspects of the argumentation process have been developed. Their combined use, necessary to achieve a comprehensive formal coverage of the argumentation phenomenon, gives rise to a nontrivial interplay between different...
Conference Paper
Agents disagree in many situations and in many ways on their beliefs, preferences and goals. Abstract argumentation frameworks are a formal model to handle disagreement, which is represented as a conflict relation between a set of arguments. To solve the conflict and identify justified arguments, a single argumentation semantics is applied at a glo...
Article
Full-text available
The field of computational models of argument is emerging as an important aspect of artificial intelligence research. The reason for this is based on the recognition that if we are to develop robust intelligent systems, then it is imperative that they can handle incomplete and inconsistent information in a way that somehow emulates the way humans t...
Article
In this paper we consider the impact of configuration of abstract argumentation reasoners both when using a single solver and choosing combinations of framework representation–solver options; and also when composing portfolios of algorithms. To exemplify the impact of the framework–solver configuration we consider one of the most configurable solve...
Article
Full-text available
Humans argue.1 This distinctive feature is at the same time an important cognitive capacity and a powerful social phenomenon. It has attracted attention and careful analysis since the dawn of civilization, being intimately related to the origin of any form of social organization, from political debates to law, and of structured thinking, from philo...
Conference Paper
Full-text available
Combining computational models of argumentation with probability theory has recently gained increasing attention, in particular with respect to abstract argumentation frameworks. Approaches following this idea can be cate-gorised into the constellations and the epistemic approach. While the former considers probability functions on the subgraphs of...
Conference Paper
In the light of the increasing interest in efficient algorithms for solving abstract argumentation problems and the pervasive availability of multicore machines, a natural research issue is to combine existing argumentation solvers into parallel portfolios. In this work, we introduce six methodologies for the automatic configuration of parallel por...
Article
Full-text available
Optimization - minimization or maximization - in the lattice of subsets is a frequent operation in Artificial Intelligence tasks. Examples are subset-minimal model-based diagnosis, nonmonotonic reasoning by means of circumscription, or preferred extensions in abstract argumentation. Finding the optimum among many admissible solutions is often harde...
Chapter
This paper presents the design, development and experimentation of ArgMed, an interactive system aimed at supporting decision making processes that occur during clinical discussions. Clinical discussions take place on a regular basis in hospital wards and provide the forum for specialists of various medical disciplines to focus on critical cases, d...
Article
Dung's argumentation frameworks are adopted in a variety of applications, from argument-mining, to intelligence analysis and legal reasoning. Despite this broad spectrum of already existing applications, the mostly adopted solver-in virtue of its simplicity-is far from being comparable to the current state-of-The-Art solvers. On the other hand, mos...
Conference Paper
Big data analytics in healthcare would be almost useless, without suitable tools allowing users "see" them, and gain insight for their situated decisions. The VVH (Valuable Visualization in Healthcare) workshop focuses on the role of interactive data visualization tools by which people can make sense of healthcare data; these data include sensor da...
Article
This report documents the program and the outcomes of Dagstuhl Perspectives Workshop 15362 "Present and Future of Formal Argumentation". The goal of this Dagstuhl Perspectives Workshop was to gather the world leading experts in formal argumentation in order to develop a SWOT (Strength, Weaknesses, Opportunities, Threats) analysis of the current s...
Article
Full-text available
Clinical discussions usually taking place in healthcare structures allow medical specialists to focus on critical cases, debate about different diagnostic hypotheses, identify therapeutic protocols, or choose among alternative treatments. This paper presents an argumentation-based approach to the analysis of clinical discussions, with the aim of pr...
Article
argumentation frameworks (AFs) are one of the central formalisms in AI; equipped with a wide range of semantics, they have proven useful in several application domains. We contribute to the systematic analysis of semantics for AFs by connecting two recent lines of research - the work on input/output frameworks and the study of the expressiveness of...
Chapter
Incompleteness and undecidedness are pervasively present in human reasoning activities and make the definition of the relevant computational models challenging. In this discussion paper we focus on one such model, namely abstract argumentation frameworks, and examine several flavours of incompleteness and undecidedness thereof, by providing a conce...
Article
This papers tackles the fundamental questions arising when looking at argumentation frameworks as interacting components, characterized by an Input/Output behavior, rather than as isolated monolithical entities. This modeling stance arises naturally in some application contexts, like multi-agent systems, but, more importantly, has a crucial impact...
Article
Full-text available
Abstract argumentation framework (\AFname) is a unifying framework able to encompass a variety of nonmonotonic reasoning approaches, logic programming and computational argumentation. Yet, efficient approaches for most of the decision and enumeration problems associated to \AFname s are missing, thus potentially limiting the efficacy of argumentati...
Article
This research note provides novel results concerning the incremental computation of the stable and ideal argumentation semantics, by extending the division-based method presented in [1] and correcting a flawed claim given there. As a basis for these results, the note synthetically reviews and discusses the topology-related properties of directional...
Chapter
This paper proposes a new approach to support medical decision making based on the analysis of multidisciplinary clinical discussions, which are becoming routine in hospitals and other health structures. In a medical discussion, participants make important pieces of knowledge explicit, by presenting different opinions, providing evidences that supp...
Article
This article presents a participatory design approach to Decision Support Systems, which is specifically built to face the socio-technical gap that often impedes DSS acceptability by end-users in real work environments. The approach has been experimented in two case studies in the field of health-related emergencies, namely earthquake and pandemic...
Article
Enumerating semantics extensions in abstract argumentation is generally an intractable problem. For preferred semantics four implementations have been recently proposed, CONArg2, AspartixM, PrefSAT and NAD-Alg, with significant runtime variations. This work is a first empirical evaluation of the performance of these implementations with the hypothe...
Article
In existing literature, little attention has been paid to the problems of how the uncertainty reflected by natural language text (e.g. verbal and linguistic uncertainty) can be explicitly formulated in argumentation schemes, and how argumentation schemes enriched with various types of uncertainty can be exploited to support argumentation mining and...
Article
Semantics extensions are the outcome of the argumentation reasoning process: enumerating them is generally an intractable problem. For preferred semantics two efficient algorithms have been recently proposed, PrefSAT and SCC-P, with significant runtime variations. This preliminary work aims at investigating the reasons (argumentation framework feat...
Article
Enumerating semantics extensions in abstract argumentation is generally an intractable problem. For preferred semantics four algorithms have been recently proposed, AspartixM, NAD-Alg, PrefSAT and SCC-P, with significant runtime variations. This work is a first comprehensive exploration of the graph features and of their impact on the execution tim...
Article
Epistemic probabilities in argumentation frameworks are meant to represent subjective degrees of belief in the acceptance of arguments. As such, they are subject to some rationality conditions, taking into account the attack relation between arguments. This paper provides an advancement with respect to the previous literature on this matter by cast...
Chapter
Full-text available
This chapter aims at comparing and relating belief revision and argumen-tation as approaches to model reasoning processes. Referring to some prominent literature references in both fields, we will discuss their (implicit or explicit) assumptions on the modeled processes and hence commonalities and differences in the forms of reasoning they are suit...
Conference Paper
Full-text available
This paper presents a novel SAT-based approach for the computation of extensions in abstract argumentation, with focus on preferred semantics, and an empirical evaluation of its performances. The approach is based on the idea of reducing the problem of computing complete extensions to a SAT problem and then using a depth-first search method to deri...
Article
The theory of abstract argumentation frameworks (afs) has, in the main, focused on finite structures, though there are many significant contexts where argumentation can be regarded as a process involving infinite objects. To address this limitation, in this paper we propose a novel approach for describing infinite afs using tools from formal langua...
Conference Paper
The paper presents the interdisciplinary research activity carried out to design ArgMED, an interactive tool devoted to the documentation and analysis of medical discussions. Meetings among different medical specialists take place everyday in every hospital ward in case of difficult diagnoses or rare pathologies. Discussions occurring in such meeti...
Article
This paper introduces Input/Output Argumentation Frameworks, a novel approach to characterize the behavior of an argumentation framework as a sort of black box exposing a well-defined external interface. As a starting point, we define the novel notion of semantics decomposability and analyze complete, stable, grounded and preferred semantics in thi...
Article
Full-text available
This paper presents an overview on the state of the art of semantics for abstract argumentation, covering both some of the most influential literature proposals and some general issues concerning semantics definition and evaluation. As to the former point, the paper reviews Dung's original notions of complete, grounded, preferred, and stable semant...
Conference Paper
In recent years a large corpus of studies has arisen from Dung's seminal abstract model of argumentation, including several extensions aimed at increasing its expressiveness. Most of these works focus on the case of finite argumentation frameworks, leaving the potential practical applications of infinite frameworks largely unexplored. In the contex...
Article
This paper introduces a novel parametric family of semantics for abstract argumentation called resolution-based and analyzes in particular the resolution-based version of the traditional grounded semantics, showing that it features the unique property of satisfying a set of general desirable properties recently introduced in the literature. Additio...
Article
Full-text available
The issue of representing attacks to attacks in argumentation is receiving an increasing attention as a useful conceptual modelling tool in several contexts. In this paper we present AFRA, a formalism encompassing unlimited recursive attacks within argumentation frameworks. AFRA satisfies the basic requirements of definition simplicity and rigorous...
Article
This paper proposes a novel computational model that allows the dynamic adaptation of the information to be presented to the user in the frame of a web application. In adaptive web-based hypermedia systems, content and presentation are usually dealt with independently and sequentially, generating content first and then adapting its presentation. By...
Conference Paper
Full-text available
This paper presents a user-centered design methodology for Decision Support Systems (DSSs), which is specifically built to face the socio-technical gap that often impedes DSS acceptability by end users in real work environments. The methodology has been experimented in two case studies in the field of health-related emergencies, namely earthquake a...
Conference Paper
Full-text available
We consider the problem of counting (without explicitly enumerating) extensions prescribed by multiple-status semantics in abstract argumentation. Referring to Dung's traditional stable and preferred semantics and to the recently introduced resolution-based grounded semantics (GR*), we show that in general extension counting is computationally hard...
Conference Paper
Full-text available
In the traditional definition of Dung’s abstract argumentation framework (AF\ensuremath{AF}), the notion of attack is understood as a relation between arguments, thus bounding attacks to start from and be directed to arguments. This paper introduces a generalized definition of abstract argumentation framework called AFRA\ensuremath{AFRA} (Argumenta...
Article
The issue of formalizing skepticism relations between argumentation semantics has been considered only recently in the literature. In this paper we provide a twofold contribution to this kind of analysis. First, starting from the traditional concepts of skeptical and credulous acceptance, we introduce a comprehensive set of seven skepticism relatio...
Chapter
An abstract argument system or argumentation framework, as introduced in a seminal paper by Dung [13], is simply a pair
Conference Paper
Full-text available
This paper describes a preliminary proposal of an argumentation-based approach to modeling articulated decision support contexts. The proposed approach encom- passes a variety of argument and attack schemes aimed at representing basic knowledge and reasoning patterns for decision support. Some of the defined attack schemes involve attacks directed...
Conference Paper
Full-text available
In the context of Dung's theory of abstract ar- gumentation frameworks, the recently introduced resolution-based grounded semantics features the unique property of fully complying with a set of general requirements, only partially satisfied by previous literature proposals. This paper con- tributes to the investigation of resolution-based grounded...
Conference Paper
Full-text available
The issue of characterizing classes of argumentation frameworks where different semantics agree has been considered in the literature with main focus on the relationships between agreement and topological properties. This paper contributes to this kind of investigation from a complementary perspective, by introducing a systematic classification of...
Article
In this paper we study the computational complexity of Fuzzy Qualitative Temporal Algebra (QA(fuz)), a framework that combines qualitative temporal constraints between points and intervals, and allows modelling vagueness and uncertainty. Its tractable fragments can be identified by generalizing the results obtained for crisp Constraint Satisfaction...
Conference Paper
Full-text available
In a recent work we have proposed a comprehensive set of evaluation criteria for argumentation semantics and we have shown that none of a set of semantics including both traditional and recent proposals is able to meet all criteria. This naturally raises the question whether such criteria are actually satisfiable altogether: this paper provides a p...
Article
Full-text available
The aim of this work is to integrate the ideas of flexibility and uncertainty into Allen's interval-based temporal logic [1], defining a new formalism (IA f uz) which extends classical In-terval Algebra (IA). We refer to Dubois, Fargier & Prade approach to Fuzzy Constraint Sat-isfaction Problem (F CSP) [3], in which constraints are satisfied to a d...
Conference Paper
Full-text available
The issue of formalizing skepticism relations between argu- mentation semantics has been considered only recently in the literature. In this paper, we contribute to this kind of analysis by providing a sys- tematic comparison of a significant set of literature semantics (namely grounded, complete, preferred, stable, semi-stable, ideal, prudent, and...
Conference Paper
Starting from the complexity classification of qualitative algebra recently proposed by Jonsson and Krokhin, we study the tractable fragments of fuzzy qualitative algebra QA<sup>fuz</sup>, an integrated framework able to deal with qualitative temporal constraints between points and intervals affected by vagueness and uncertainty. To do this we gene...
Article
The increasing variety of semantics proposed in the context of Dung's theory of argumentation makes more and more inadequate the example-based approach commonly adopted for evaluating and comparing different semantics. To fill this gap, this paper provides two main contributions. First, a set of general criteria for semantics evaluation is introduc...
Article
This paper presents a concrete experience of Knowledge Engineering, which, starting from a specific problem which occurred during the development of ASTRA, a knowledge-based system for preventive diagnosis of power transformers, turned out to provide significant insights concerning modeling of uncertain knowledge. In particular, it was observed tha...
Article
The satellite-scheduling problem represents an interesting field to test non-conventional temporal solvers because scheduling-problems are inherently over-constrained and, moreover, the tasks may be known in an imprecise and uncertain manner. In this paper we present an application of our fuzzy temporal reasoning system to the satellite-scheduling...
Article
Full-text available
In the context of Dung's theory of argumentation frame-works, comparisons between argumentation semantics are often focused on the different behavior they show in some (more or less peculiar) cases. It is also interesting however to characterize situations where (under some reasonably general assumptions) different semantics behave ex-actly in the...
Article
The aim of this work is to integrate the ideas of flexibility and uncertainty into Allen's interval-based temporal framework, defining a new formalism, called , which extends classical Interval Algebra (IA), in order to express qualitative fuzzy constraints between intervals. We generalize the classical operations between IA-relations to -relations...
Conference Paper
In the context of Dung's theory of abstract argumentation frameworks, the comparison between different semantics is often carried out by resorting to some specific examples considered particularly meaningful. This kind of com- parison needs to be complemented by more general evaluation criteria based on "example-independent" basic principles. We re...
Article
In argumentation theory, Dung's abstract framework provides a unifying view of several alternative semantics based on the notion of extension. In this context, we propose a general recursive schema for argumentation semantics, based on decomposition along the strongly connected components of the argumentation framework. We introduce the fundamental...
Conference Paper
Full-text available
Analyzing argumentation semantics with respect to the no- tion of skepticism is an important issue for developing general and well- founded comparisons among existing approaches. In this paper, we show that the notion of skepticism plays also a signiflcant role in order to better understand the behavior of a speciflc semantics in difierent situa- t...
Article
The role of argumentation in supporting various forms of interaction among possibly conflicting autonomous agents has been explicitly recognized in the literature. In argumentation, conflict management is carried out by the formal process of defeat status computation. In this paper we consider the generalization of this process to a distributed set...
Article
Full-text available
In the context of Dung's argumentation framework, we propose a general recursive schema for argumentation semantics, based on decomposition along the strongly connected components of the argumentation framework.
Conference Paper
In the context of Dung’s abstract framework for argumentation, two main semantics have been considered to assign a defeat status to arguments: the grounded semantics and the preferred semantics. While the two semantics agree in most situations, there are cases where the preferred semantics appears to be more powerful. However, we notice that the pr...
Article
In this work we address the problem of representing and reasoning with temporal knowledge in a very general and flexible manner. To this aim we propose a model of integration of quantitative and qualitative temporal information affected by vagueness and uncertainty. We extend our fuzzy qualitative temporal framework IA fuz integrating the treatment...
Conference Paper
Full-text available
In argumentation theory, Dung's abstract framework pro- vides a unifying view of several alternative semantics based on the notion of extension. Recently, a new semantics has been introduced to solve the problems related to counterintuitive results produced by literature proposals. In this semantics, an important role is played by a recursive schem...
Article
Full-text available
This paper provides a preliminary investigation to- wards the definition of a general framework for the comparison of extension-based argumentation semantics with respect to the notion of skepticism. We identify seven justification states for arguments and define two alternative skepticism relations between semantics, which induce a partial order o...