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Refinements of Graph Transformation Systems via Rule Expressions
No full textGraph transformation systems are formal models of computational systems, specified by rules that describe the atomic steps of the system. A refinement of a graph transformation system is given by associating with each of its rules a composition of rules of a refining system, that has the same visible effect as the original rule. The basic composition operations on graph transformation rules are sequential and parallel composition, corresponding to temporal and spatial refinements respectively. Syntactically refinements are represented by rule expressions that describe how the refining rules shall be composed
Spatial and Temporal Refinement of Graph Transformation Systems
No full textGraph transformation systems support the formal modeling of dynamic, concurrent, and distributed systems. States are given by their graphical structure, and transitions are modeled by graph transformation rules. In this paper we investigate two kinds of refinement relations for graph transformation systems in order to support the development of a module concept for graph transformation systems. In a spatial refinement each rule is refined by an amalgamation of rules, in a temporal refinement it is refined by a sequence of rules
Refinements and Modules for Typed Graph Transformation Systems
No full textSpatial and temporal refinement relations between typed graph transformation systems have been introduced in [6,7]. In a spatial refinement a transformation rule is refined by an amalgamation of rules while in a temporal refinement it is refined by a sequence of rules: in both cases, the refinement relation supports the modeling of implementation. In the first part of this paper, we further investigate the properties of spatial and temporal refinements while, in the second part, we employ them for the development of a module concept for typed graph transfor-mation systems. Finally, as a first step towards an algebra of modules, we introduce the operations of union and composition of modules
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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