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Francesco Calimeri

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13 papers

2 author rows

KR Conference 2024 Conference Paper

LLASP: Fine-tuning Large Language Models for Answer Set Programming

Erica Coppolillo
Francesco Calimeri
Giuseppe Manco
Simona Perri
Francesco Ricca

Recently, Large Language Models (LLMs) have showcased their potential in various natural language processing tasks, including code generation. However, while significant progress has been made in adapting LLMs to generate code for several imperative programming languages and tasks, there remains a notable gap in their application to declarative formalisms, such as Answer Set Programming (ASP). In this paper, we move a step towards exploring the capabilities of LLMs for ASP code generation. First, we perform a systematic evaluation of several state-of-the-art LLMs. Despite their power in terms of number of parameters, training data and computational resources, empirical results demonstrate inadequate performances in generating correct ASP programs. Therefore, we propose LLASP, a fine-tuned lightweight model specifically trained to encode fundamental ASP program patterns. To this aim, we create an ad-hoc dataset covering a wide variety of fundamental problem specifications that can be encoded in ASP. Our experiments demonstrate that the quality of ASP programs generated by LLASP is remarkable. This holds true not only when compared to the non-fine-tuned counterpart but also when compared to the majority of eager LLM candidates, particularly from a semantic perspective. All the code and data used to perform the experiments are publicly available: https: //github. com/EricaCoppolillo/LLASP.

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AILAW Journal 2023 Journal Article

Compliance checking on first-order knowledge with conflicting and compensatory norms: a comparison among currently available technologies

Livio Robaldo
Sotiris Batsakis
Roberta Calegari
Francesco Calimeri
Megumi Fujita
Guido Governatori
Maria Concetta Morelli
Francesco Pacenza

Abstract This paper analyses and compares some of the automated reasoners that have been used in recent research for compliance checking. Although the list of the considered reasoners is not exhaustive, we believe that our analysis is representative enough to take stock of the current state of the art in the topic. We are interested here in formalizations at the first-order level. Past literature on normative reasoning mostly focuses on the propositional level. However, the propositional level is of little usefulness for concrete LegalTech applications, in which compliance checking must be enforced on (large) sets of individuals. Furthermore, we are interested in technologies that are freely available and that can be further investigated and compared by the scientific community. In other words, this paper does not consider technologies only employed in industry and/or whose source code is non-accessible. This paper formalizes a selected use case in the considered reasoners and compares the implementations, also in terms of simulations with respect to shared synthetic datasets. The comparison will highlight that lot of further research still needs to be done to integrate the benefits featured by the different reasoners into a single standardized first-order framework, suitable for LegalTech applications. All source codes are freely available at https://github.com/liviorobaldo/compliancecheckers, together with instructions to locally reproduce the simulations.

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ICRA Conference 2021 Conference Paper

Optimized 3D path planner for steerable catheters with deductive reasoning

Alice Segato
Valentina Corbetta
Jessica Zangari
Simona Perri
Francesco Calimeri
Elena De Momi

Keyhole neurosurgery is challenging, due to the complex anatomy of the brain and the inherent risk of damaging vital structures while reaching the surgical target. This paper presents a path planner for safe and effective neurosurgical interventions. The strengths of the proposed framework lay in the integration of multiple risk structures combined into a deductive method for fast and intuitive user interaction, and a modular architecture. The tool is intended to support neurosurgeons at quickly determining the most appropriate surgical trajectory through the brain matter with minimized risk; the user interface guides the user through the decision making process and helps save planning time of neurosurgical interventions. Risk structures and trajectories can be visualized in an intuitive way, thanks to a 3D brain surgery simulator developed with Unity. A qualitative evaluation with clinical experts shows the practical relevance, while a quantitative performance and functionality analysis proves the robustness and effectiveness of the system with respect to literature.

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AIIM Journal 2020 Journal Article

Data reduction and data visualization for automatic diagnosis using gene expression and clinical data

Pierangela Bruno
Francesco Calimeri
Alexandre Sébastien Kitanidis
Elena De Momi

Accurate diagnoses of specific diseases require, in general, the review of the whole medical history of a patient. Currently, even though many advances have been made for disease monitoring, domain experts are still requested to perform direct analyses in order to get a precise classification, thus implying significant efforts and costs. In this work we present a framework for automated diagnosis based on high-dimensional gene expression and clinical data. Given that high-dimensional data can be difficult to analyze and computationally expensive to process, we first perform data reduction to transform high-dimensional representations of data into a lower dimensional space, yet keeping them meaningful for our purposes. We used then different data visualization techniques to embed complex pieces of information in 2-D images, that are in turn used to perform diagnosis relying on deep learning approaches. Experimental analyses show that the proposed method achieves good performance, featuring a prediction Recall value between 91% and 99%.

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AIJ Journal 2016 Journal Article

Design and results of the Fifth Answer Set Programming Competition

Francesco Calimeri
Martin Gebser
Marco Maratea
Francesco Ricca

Answer Set Programming (ASP) is a well-established paradigm of declarative programming that has been developed in the field of logic programming and non-monotonic reasoning. Advances in ASP solving technology are customarily assessed in competition events, as it happens for other closely related problem solving areas such as Boolean Satisfiability, Satisfiability Modulo Theories, Quantified Boolean Formulas, Planning, etc. This paper reports about the fifth edition of the ASP Competition by covering all aspects of the event, ranging from the new design of the competition to an in-depth analysis of the results. The paper comprises also additional analyses that were conceived for measuring the progress of the state of the art, as well as for studying aspects orthogonal to solving technology, such as the effects of modeling. A detailed picture of the progress of the state of the art in ASP solving is drawn, and the ASP Competition is located in the spectrum of related events.

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AAAI Conference 2010 Conference Paper

Enhancing ASP by Functions: Decidable Classes and Implementation Techniques

Francesco Calimeri
Susanna Cozza
Giovambattista Ianni
Nicola Leone

This paper summarizes our line of research about the introduction of function symbols (functions) in Answer Set Programming (ASP) – a powerful language for knowledge representation and reasoning. The undecidability of reasoning on ASP with functions, implied that functions were subject to severe restrictions or disallowed at all, drastically limiting ASP applicability. We overcame most of the technical difficulties preventing this introduction, and we singled out a highly expressive class of programs with functions (FG-programs), allowing the (possibly recursive) use of function terms in the full ASP language with disjunction and negation. Reasoning on FG-programs is decidable, and they can express any computable function (causing membership in this class to be semi-decidable). We singled out also FD-programs, a subset of FG-programs which are effectively recognizable, while keeping the computability of reasoning. We implemented all results into the DLV system, thus obtaining an ASP system allowing to encode any computable function in a rich and fully declarative KRR language, ensuring termination on every FG program. Finally, we singled out the class of DFRP programs, where decidability of reasoning is guaranteed and Prolog-like functions are allowed.

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JELIA Conference 2006 Conference Paper

Decidable Fragments of Logic Programming with Value Invention

Francesco Calimeri
Susanna Cozza
Giovambattista Ianni

Abstract The issue of value invention in logic programming embraces many scenarios, such as logic programming with function symbols, object oriented logic languages, inter-operability with external sources of knowledge, set unification. This paper introduces a framework embedding value invention in a general context. The class of programs having a suitable (but, in general, not decidable) ‘finite grounding property’ is identified, and the class of ‘value invention restricted’ programs is introduced. Value invention restricted programs have the finite grounding property and can be decided in polynomial time. They are, in a sense, the broadest polynomially decidable class having this property, whenever no assumption can be made about the nature of invented values (while this latter is the case in the specific literature about logic programming with function symbols). Relationships with existing formalisms are eventually discussed; in particular, value invention restricted programs subsume ω -restricted programs and are incomparable with finitary programs.

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IJCAI Conference 2005 Conference Paper

Declarative and Computational Properties of Logic Programs with Aggregates

Francesco Calimeri
Wolfgang Faber
Nicola Leone
Simona

We investigate the properties of logic programs with aggregates. We mainly focus on programs with monotone and antimonotone aggregates (LPA m, a programs). We define a new notion of unfounded set for LPA m, a programs, and prove that it is a sound generalization of the standard notion of unfounded set for aggregate-free programs. We show that the answer sets of an LPA m, a program are precisely its unfounded-free models. We define a well-founded operator WP for LPA m, a programs; we prove that its total fixpoints are precisely the answer sets of P, and its least fixpoint Wω P (∅) is contained in the intersection of all answer sets (if P admits an answer set). Wω P (∅) is efficiently computable, and for aggregate-free programs it coincides with the well-founded model. We carry out an in-depth complexity analysis in the general framework, including also nonmonotone aggregates. We prove that monotone and antimonotone aggregates do not increase the complexity of cautious reasoning, which remains in co-NP. Nonmonotone aggregates, instead, do increase the complexity by one level in the polynomial hierarchy. Our results allow also to generalize and speedup ASP systems with aggregates.

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JELIA Conference 2004 Conference Paper

A System with Template Answer Set Programs

Francesco Calimeri
Giovambattista Ianni
Giuseppe Ielpa
Adriana Pietramala
Maria Carmela Santoro

Abstract Although ASP systems have been extended in many directions, they still miss features which may be helpful towards industrial applications, like capabilities of quickly introduce new predefined constructs or to deal with compound data structures and module. We show here an implementation on top of the DLV system of DLP T language, which features increased declarativity, code readability, compactness and reusability.

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NMR Workshop 2004 Conference Paper

Enhancing answer set programming with templates

Giovambattista Ianni
Giuseppe Ielpa
Adriana Pietramala
Maria Carmela Santoro
Francesco Calimeri

The work aims at extending Answer Set Programming (ASP) with the possibility of quickly introducing new predefined constructs and to deal with compound data structures: we show how ASP can be extended with ‘template’ predicate’s definitions. We present language syntax and give its operational semantics. We show that the theory supporting our ASP extension is sound, and that program encodings are evaluated as efficiently as ASP programs. Examples show how the extended language increases declarativity, readability, compactness of program encodings and code reusability. 1.

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JELIA Conference 2004 Conference Paper

New DLV Features for Data Integration

Francesco Calimeri
Manuela Citrigno
Chiara Cumbo
Wolfgang Faber 0001
Nicola Leone
Simona Perri
Gerald Pfeifer

Abstract The DLV system is currently employed in projects on data integration – a challenging application area for Answer Set Programming. The present system description illustrates some new optimization techniques, which significantly enhance the general performance of DLV, and especially in the context of data integration.

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NMR Workshop 2002 Conference Paper

Pruning operators for answer set programming systems

Francesco Calimeri
Wolfgang Faber 0001
Nicola Leone
Gerald Pfeifer

Answer Set Programming (ASP) is a novel paradigm in Logic Programming, which allows for solving problems in a simple and highly declarative way. The language of ASP (function-free disjunctive logic programming) is very expressive and supports the representation of problems of high computational complexity (specifically, all problems in the complexity class UP = NPNP). Importantly, the ASP encoding of a large variety of problems is often very concise, simple, and elegant. In this paper, we explain the computational process performed by ASP systems, with a focus on search space pruning, which is crucial for efficiency. We analyze the properties of two main pruning operators, namely (Fitting’s operator and Well-founded operator), discuss their peculiarities and differences with respect to efficiency and effectiveness. We design an intelligent strategy for combining the two operators, which exploits the advantages of both. We implement our approach in the ASP system DLV, and perform some experiments. The experiments show interesting results, and evidence how the choice of the pruning operator affects the performance of ASP systems.

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JELIA Conference 2002 Conference Paper

The DLV System

Nicola Leone
Gerald Pfeifer
Wolfgang Faber 0001
Francesco Calimeri
Tina Dell'Armi
Thomas Eiter
Georg Gottlob
Giovambattista Ianni

Abstract The development of the DLV system has started as a research projectfinanced by FWF (the Austrian Science Funds) in 1996, and has evolved into an international collaboration over the years. Currently, the University of Calabria and TU Wien participate in the project, supported by a scientific-technological collaboration between Italy and Austria. At the time of writing, the latest version of the system has been released on April 12, 2002.

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