1,721,102 research outputs found
Compact and Tractable Automaton-based Representations for Time Granularities
No full textMost approaches to time granularity proposed in the literature are based on algebraic and logical formalisms [J. Euzenat, A.
Montanari, Time granularity, in: M. Fisher, D. Gabbay, L. Vila (Eds.), Handbook of Temporal Reasoning in Artificial Intelligence,
Elsevier, 2005, pp. 59–118]. Here we follow an alternative automaton-based approach, originally outlined in [U. Dal Lago,
A. Montanari, Calendars, time granularities, and automata, in: Proceedings of the 7th International Symposium on Spatial and
Temporal Databases, SSTD, in: LNCS, vol. 2121, Springer, 2001, pp. 279–298], which makes it possible to deal with infinite time
granularities in an effective and efficient way. Such an approach provides a neat solution to fundamental algorithmic problems, such as the granularity equivalence and granule conversion problems, which have been often neglected in the literature. In this paper, we focus our attention on two basic optimization problems for the automaton-based representation of time granularities, namely, the problem of computing the smallest representation of a time granularity and that of computing the most tractable representation of it, that is, the one on which crucial algorithms, such as granule conversion algorithms, run fastest
On the Equivalence of Automaton-based Representations of Time Granularities
Full text linkA time granularity can be viewed as the partitioning of a temporal domain in groups of elements, where each group is perceived as an indivisible unit. In this paper we explore an automaton-based approach to the management of time granularity that compactly represents time granularities as single-string automata with counters, that is, Buchi automata, extended with counters, that accept a single infinite word. We focus our attention on the equivalence problem for the class of restricted labeled single-string automata (RLA for short). The equivalence problem for RLA is the problem of establishing whether two given RLA represent the same time granularity. The main contribution of the paper is the reduction of the (non-)equivalence problem for RLA to the satisfiability problem for linear diophantine equations with bounds on variables. Since the latter problem has been shown to be NP-complete, we have that the RLA equivalence problem is in co-NP
The Logic of Prefixes and Suffixes is Elementary under Homogeneity*
No full textIn this paper, we study the finite satisfiability problem for the logic BE under the homogeneity assumption. BE is the cornerstone of Halpern and Shoham's interval temporal logic, and features modal operators corresponding to the prefix (a.k.a. "Begins") and suffix (a.k.a. "Ends") relations on intervals. In terms of complexity, BE lies in between the "Chop" logic C, whose satisfiability problem is known to be non-elementary, and the PSPACE-complete interval logic D of the sub-interval (a.k.a. "During") relation. BE was shown to be EXPSPACEhard, and the only known satisfiability procedure is primitive recursive, but not elementary. Our contribution consists of tightening the complexity bounds of the satisfiability problem for BE, by proving it to be EXPSPACE-complete. We do so by devising an equi-satisfiable normal form with boundedly many nested modalities. The normalization technique resembles Scott's quantifier elimination, but it turns out to be much more involved due to the limitations enforced by the homogeneity assumption
Games, Automata, Logic, and Formal Verification (GandALF 2013) - Special Issue of the journal Information and Computation, Editorial pp. 1-2
Full text linkCiaramella: A Synchronous Data Flow Programming Language For Audio DSP
No full textVarious programming languages have been developed
specifically for audio DSP in the last decades, yet only
a handful of industrial and commercial applications are
known to actually use them. We assume that this is
due to some common deficiencies of such languages,
namely the tight coupling between syntax and computational
model, which limits modularity, and the adoption
of programming paradigms that are conceptually distant
from conventional DSP formalism. We propose a new
audio DSP programming language, called Ciaramella,
based on the synchronous data flow (SDF) computational
model and featuring a fully declarative syntax to address
these issues. A source-to-source compiler which translates
Ciaramella code to C++ and MATLAB programs
has been developed. We have checked that our solution
allows to naturally represent and correctly schedule
highly-interdependent DSP systems such as Wave Digital
Filters (WDFs) which would be hard to handle in
current audio DSP languages
Ciaramella: A Synchronous Data Flow Programming Language For Audio DSP
Full text linkVarious programming languages have been developed specifically for audio DSP in the last decades, yet only a handful of industrial and commercial applications are known to actually use them. We assume that this is due to some common deficiencies of such languages, namely the tight coupling between syntax and computational model, which limits modularity, and the adoption of programming paradigms that are conceptually distant from conventional DSP formalism. We propose a new audio DSP programming language, called Ciaramella, based on the synchronous data flow (SDF) computational model and featuring a fully declarative syntax to address these issues. A source-to-source compiler which translates Ciaramella code to C++ and MATLAB programs has been developed. We have verified that our solution allows to naturally represent and correctly schedule highly-interdependent DSP systems such as Wave Digital Filters (WDFs) which would be hard to handle in current audio DSP languages
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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