1,720,980 research outputs found
On collecting semantics for program analysis
Full text linkReasoning on a complex system in the abstract interpretation theory starts with a formal description of the system behavior specified by a collecting semantics. We take the common point of view that a collecting semantics is a very precise semantics from which other abstractions may be derived. We elaborate on both the concepts of precision and derivability, and introduce a notion of adequacy which tell us when a collecting semantics is a good choice for a given family of abstractions. We instantiate this approach to the case of first-order functional programs by considering three common collecting semantics and some abstract properties of functions. We study their relative precision and give a constructive characterization of the classes of abstractions which are adequate for the collecting semantics
Building complete abstract interpretations in a linear logic-based setting
Full text linkCompleteness is an important, but rather uncommon, property of abstract interpretations, ensuring that abstract computations are as precise as possible w.r.t, concrete ones. It turns out that completeness for an abstract interpretation depends only on its underlying abstract domains, and therefore it is an abstract domain property. Recently, the first two authors proved that for a given abstract domain A, in all significant cases, there exists the most abstract domain, called least complete extension of A, which includes A and induces a complete abstract interpretation. In addition to the standard formulation, we introduce and study a novel and particularly interesting type of completeness, called observation completeness. Standard and observation completeness are here considered in the context of quantales, i.e. models of linear logic, as concrete interpretations. In this setting, we prove that various kinds of least complete and observationally complete extensions exist and, more importantly, we show that such complete extensions can all be explicitly characterized by elegant linear logic-based formulations. As an application, we determine the least complete extension of a generic abstract domain w.r.t. a standard bottom-up semantics for logic programs observing computed answer substitutions. This general result is then instantiated to the relevant case of groundness analysis
On the Need for a Common API for Abstract Domains of Object-Oriented Programs
No full textIn the last years almost all families of programming languages, from imperative to functional, logic, object-oriented and machine code, have been subject to static analysis by abstract interpretation. The use of a principled approach to static analysis based on the theory of abstract interpretation provided mathematical tools to reason about program properties and allowed for the rigorous and incremental design of precise and scalable static analyzers, ensuring soundness by construction. The large variety of abstract domains for many different programming languages, the ability to combine and refine them with standard abstract interpretation tools and the availability of mature abstract domain libraries allowed easily porting, reusing and experimenting with techniques born in a specific family to other programming languages and properties. Since the use of abstract interpretation for the analysis of object-oriented languages is less common than in other application fields of static analysis, in order to increase its adoption, we advocate the need to establish a common interface for designing and implementing abstract domains for the static analysis of Java-like programs. This interface should allow developing abstract domains pluggable in a generic abstract interpreter, as it is customary, for example, in abstract interpretation-based static analysis of numerical properties
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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