1,720,991 research outputs found
Notes on Ginsberg's multivalued logics
No full textThe use of multivalued logics for knowledge representation and nonmonotonic reasoning has often been advocated, in particular within the general framework proposed by Ginsberg in his paper “Multivalued logics: a uniform approach to reasoning in artificial intelligence.” His system is based on a multivalued logic with an arbitrary number of truth values classified with respect to two partial orders, a truth order and a knowledge order. This classification is very interesting and gives an intuitive appeal to the framework. In this paper the work by Ginsberg is critically reviewed, pointing out some flaws and ways to overcome them. Moreover, we present some ideas on how to modify the original schema in order to obtain a more semantically well‐founded framework. L'utilisation de la Iogique multivalente pour la représentation des connaissances et le raisonnement non monotone a souvent été préconisée, en particulier à l'intérieur du cadre général proposé par Ginsberg dans son article intitulé? Multivalued logics: a uniform approach to reasoning in artificial intelligence ? Son système est basé sur une logique multivalente comportant un nombre arbitraire de valeurs de vérité classées selon deux ordres partiels: un ordre de vérité et un ordre de connaissances. Cette classification est très intéressante et donne un attrait intuitif au cadre. Dans cet article, l'auteur examine le travail de Ginsberg, y relève des lacunes et propose des moyens de les corriger. De plus, il expose certaines idées en vue de modifier le schéma original et ainsi obtenir un meilleur cadre du point de vue de la sémantique
Logic Programming and Autoepistemic Logics: New Relations and Complexity Results
No full text. In recent years, many authors have pointed out the strict correlation between non-Horn logic programs and non-monotonic reasoning. As a result, many studies on the relations between various semantics for negation and non-monotonic logics have appeared in the literature. The analysis of these relations helps understanding the properties of the various systems and allows importing analysis from one formalism into another one. In this paper we show a one-to-one mapping between the positivistic models and moderately-grounded expansions of autoepistemic logic and a one-to-one correspondence between the minimally-supported models and the stable parsimonious expansions. These relations are then used to prove the computational complexity of reasoning with the positivistic and minimally-supported model semantics, as well as new complexity results for restricted subsets of autoepistemic logic. 1 Introduction Since the pioneering work of Clark [5], the issue of correctly characterizing the beh..
.: Exponential modelling of Ultrasound fetal growth and computer evaluation of significant parameters.
No full textExpressing the tacit knowledge of a digital library system as linked data
Full text linkLibrary organizations have enthusiastically undertaken semantic web initiatives and in particular the data publishing as linked data. Nevertheless, different surveys report the experimental nature of initiatives and the consumer difficulty in re-using data. These barriers are a hindrance for using linked datasets, as an infrastructure that enhances the library and related information services. This paper presents an approach for encoding, as a Linked Vocabulary, the "tacit" knowledge of the information system that manages the data source. The objective is the improvement of the interpretation process of the linked data meaning of published datasets. We analyzed a digital library system, as a case study, for prototyping the "semantic data management" method, where data and its knowledge are natively managed, taking into account the linked data pillars. The ultimate objective of the semantic data management is to curate the correct consumers' interpretation of data, and to facilitate the proper re-use. The prototype defines the ontological entities representing the knowledge, of the digital library system, that is not stored in the data source, nor in the existing ontologies related to the system's semantics. Thus we present the local ontology and its matching with existing ontologies, Preservation Metadata Implementation Strategies (PREMIS) and Metadata Objects Description Schema (MODS), and we discuss linked data triples prototyped from the legacy relational database, by using the local ontology. We show how the semantic data management, can deal with the inconsistency of system data, and we conclude that a specific change in the system developer mindset, it is necessary for extracting and "codifying" the tacit knowledge, which is necessary to improve the data interpretation process
An analysis of international mobility and research productivity in computer science
Full text linkIn this article, we study the international mobility of researchers in the field of computer science (CS). Our analysis hinges upon Scopus data spanning a time period of 30 years (1991–2020) and involves a total of 969,835 researchers and 8,412,543 publications. Our contribution is two-fold. First, we characterize mobility as a fairly common phenomenon in CS, we highlight a strong correlation with standard bibliometric indicators at all seniority levels and a lower propensity of female researchers to relocate internationally than their male colleagues. Second, we analyze individual career paths building from them a mobility graph and identifying common patterns, such as the most traveled connections between different countries, whether they are equally traversed in both directions and the most frequently visited countries. The temporal evolution of the above patterns within our 30-year time frame is also investigated. The United States emerged as a preferred destination for internationally mobile authors, with strong connections to China (from the early 2000s), Canada, and several prominent European countries, most notably the United Kingdom, Germany, and France
Bologna medievale, GIS e Google Earth: nuove forme di pubblicazione e fruizione per la ricerca
No full textSi presentano qui i risultati preliminari di una ricerca in progress sull’analisi degli spazi pubblici e privati in Bologna medievale. Per il XIII secolo è disponibile una massa particolarmente ingente di fonti documentarie che consentono di avere una buona quantità di informazioni sul patrimonio immobiliare urbano e sulla destinazioni degli spazi. Il trattamento seriale di tali fonti ha consentito di realizzare un sistema informativo geografico (GIS) che sta restituendo una interessante descrizione degli spazi urbani e della composizione dei patrimoni immobiliari familiari. Il GIS fornisce un valido aiuto alla ricerca grazie alla capacità di raccogliere e visualizzare sulla città le informazioni che si hanno su di essa, ma consente inoltre di distribuire in forma grafica tali dati su Web, anche attraverso semplici sistemi di navigazione territoriale. Per questo motivo è stata avviata una ulteriore fase del progetto che ha come obiettivo la pubblicazione delle informazioni contenute nel GIS sul visualizzatore territoriale 3D Google Earth per poter raggiungere e coinvolgere anche utenti non necessariamente esperti di tematiche storiche
Didattica Universitaria Online
No full textDidattica Universitaria Online (DUO) è un progetto complesso e articolato che ha lo scopo di riportare lo stato dell’arte della didattica online nelle università italiane. È stato possibile realizzare questo prodotto grazie alla collaborazione tra due Associazioni di ricerca che rappresentano punti di riferimento importanti e complementari relativamente all’uso dell’E-learning e delle tecnologie nella formazione: il Collaborative Knowledge Building Group (C.K.B.G.) (www. ckbg.org) e la Società Italiana per l’Elearning (Sie-l) (www.sie-l.it). Infatti, i quattro curatori dell’opera hanno lavorato in rappresentanza delle due Associazioni: M. Beatrice Ligorio e Elvis Mazzoni per il C.K.B.G.; Aurelio Simone e Mirella Casini Schaerf per la Sie-l. La portata dell’opera è tale che è stata necessaria un’articolazione in tre Volumi: Volume I: Modelli e Teorie che si compone di 12 Capitoli; Volume II: Esperienze che contiene 16 Capitoli; Volume III: Strumenti e Problemi articolato in 5 Capitoli. La struttura dei tre Volumi non va considerata in modo rigido, in quanto i capitoli che li compongono possono essere selezionati e ricombinati su richiesta del lettore. Si tratta, infatti, di testi in formato e-book che, oltre a presentare una natura multimediale e ipertestuale, permette anche una elevata personalizzazione selezionando capitoli dei vari volumi per comporne testi appositamente creati on-demand. Quest’opera fa parte della Collana “Con-testi e Tecnologie” curata dal C.K.B.G. Altri testi che fanno parte della Collana sono: Knowledge Building Communities: ripensare la scuola come comunità di ricerca, a cura di S. Cacciamani; Formazione, Innovazione e Tecnologia, a cura di D. Cesareni e S. Manca
Didattica Universitaria Online. Modelli e teorie
No full textQual è lo stato dell'arte della didattica online oggi nelle università italiane? Quali modelli e metodi ne rappresentano i punti di riferimento? Quali sono i problemi e le questioni ancora aperte? Questo volume si propone di riprendere di rispondere a queste domand
Analisi cefalometrica in chirurgia Maxillo-Facciale. (Studio di un sistema di computerizzazione dell'analisi diagnostica per le dismorfie maxillo-facciali).
No full textApproximate entailment
No full textApproximation techniques are widely used in many areas of Computer Science for dealing with polynomially intractable problems. The major difficulty about introducing approximation in reasoning problems is in that it is very hard to find a measure of the approximation which is not dependent on the particular problem at hand. Our goal is to introduce the notion of approximate answers to reasoning problems which are known to be computationally intractable. We focus our attention on a reasoning problem which is both very general and computationally intractable: checking whether a propositional formula in Conjunctive Normal Form entails a clause. We present two sequences of entailment relations approximating the classical one: the relations of the first sequence are sound but not complete, while the relations of the second one are complete but not sound. Both sequences converge to classical entailment and can be computed in polynomial time under some conditions. Our claim is that both these sequences are an approximation of the entailment relation, since they always provide information clearly related to the original problem. In the last part of the paper, we sketch an algorithm for computing incrementally relations of the two sequence
- …
