1,721,131 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Hierarchical concurrent systems : equivalence, analysis and structuring
No full textDans le cadre de la vérification des systèmes concurrents, nous étudions les réseaux de Petri et une de leurs extensions, les NUPN (acronyme anglais de « réseaux de Petri à unités imbriquées »), qui leur apportent modularité et hiérarchie par une structure en processus séquentiels, imbriqués sous la forme d’un arbre. Nous proposons diverses techniques permettant de résoudre plusieurs questions relatives aux réseaux de Petri et aux NUPN. D'abord, nous exposons des approches pour décider efficacement l'isomorphisme des réseaux de Petri et des NUPN. Puis, nous définissons des algorithmes pour détecter les places mortes et les transitions mortes, ce qui permet l'élimination du code mort, ainsi que des algorithmes pour détecter les places concurrentes, qui donnent des informations sur la concurrence des réseaux. Enfin, nous abordons la traduction automatisée des réseaux de Petri en réseaux d’automates communicants, en NUPN avec des processus imbriqués, ou en différentes algèbres de processus. Ces algorithmes ont été implantés et testés sur de grandes collections de réseaux d’origine académique, industrielle, ou provenant de compétitions internationales.In the context of the verification of concurrent systems, we study Petri nets and one of their extensions, NUPNs (for “Nested-Unit Petri nets”), which provide them modularity and hierarchy through a structure of sequential processes, nested in the form of a tree. We propose various techniques to address several questions concerning Petri nets and NUPNs. First, we present approaches to decide efficiently the isomorphism of Petri nets and NUPNs.Then, we define algorithms to detect dead places and dead transitions, which enable the elimination of dead code, as well as algorithms to detect concurrent places, which provide information about the concurrency of nets. Finally, we tackle the automated translation of Petri nets into networks of communicating automata, into NUPNs with nested processes, or into different process algebras.These algorithms have been implemented and tested on large collections of nets from academia, industry, or stemming from international competitions
Variations on the Author
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
CAESAR_SOLVE: A Generic Library for On-the-Fly Resolution of Alternation-Free Boolean Equation Systems
Get PDFBoolean Equation Systems (BESs) provide a useful framework for modeling various verification problems on finite-state concurrent systems, such as equivalence checking and model checking. These problems can be solved on-the-fly (i.e., without constructing explicitly the state space of the system under analysis) by using a demand-driven construction and resolution of the corresponding BES. In this report, we present a generic software library dedicated to on-the-fly resolution of alternation-free BESs (i.e., without mutually recursive minimal and maximal fixed point equations). Four resolution algorithms are currently provided by the library: algorithms A1 and A2 are general, the latter being optimized to produce small-depth diagnostics, whereas algorithms A3 and A4 are specialized for handling acyclic and disjunctive/conjunctive BESs in a memory-efficient way. The library is developed within the CADP verification toolbox using the generic OPEN/CAESAR environment and is currently used for three purposes: on-the-fly equivalence checking modulo five widely-used equivalence relations, on-the-fly model checking of regular alternation-free mu-calculus, and on-the-fly reduction of state spaces based on tau-confluence
A Generic On-the-Fly Solver for Alternation-Free Boolean Equation Systems
No full textBoolean Equation Systems are a useful formalism for modeling various verification problems of finite-state concurrent systems, in particular the equivalence checking and the model checking problems. These problems can be solved on-the-fly (i.e., without constructing explicitly the state space of the system under analysis) by using a demand-driven construction and resolution of the corresponding boolean equation system. In this report, we present a generic software library dedicated to on-the-fly resolution of alternation-free boolean equation systems. Four resolution algorithms are currently provided by the library: A1 and A2 are general algorithms, the latter being optimized to produce small-depth diagnostics, whereas A3 and A4 are specialized algorithms for handling acyclic and disjunctive/conjunctive boolean equation systems in a memory-efficient way. The library is developed within the Cadp verification toolbox and is used for both on-the-fly equivalence checking (five widely-used equivalence relations are supported) and for on-the-fly model checking of alternation-free modal mu-calculus
Specification and Analysis of Asynchronous Systems using CADP
Get PDFThe design of complex industrial critical systems involving asynchronous parallelism requires the use of formal methods, assisted by appropriate verification tools, in order to detect and correct errors as early as possible. In this chapter, we illustrate the use of the CADP toolbox for the formal modeling and verification of such systems by considering as an example a unit dedicated to the drilling of metal products. We describe in the LOTOS language two different versions of the unit, supervised by a sequential and a parallel controller, respectively. Then, we perform the generation and minimisation of the two underlying state spaces, and also the inspection (visual checking) of the smaller one, corresponding to the version equipped with a sequential controller. Finally, we analyse the behaviour of the two versions of the drilling unit by means of two complementary verification methods, based on bisimulations (equivalence checking) and temporal logics (model checking)
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