1,720,976 research outputs found
Towards efficient parsing of diagrammatic languages
No full textMany models have been presented to specify visual languages and big efforts are being made to characterize a class of visual languages which is expressive enough and, at the same time, efficient to parse. Along this direction, the positional grammar model has been defined to extend the LR parsing techniques and parse efficiently not only the string languages but also iconic languages. In this paper, we present an extension of the positional grammar model in order to describe a wide variety of diagrammatic languages. We show that this new formalism allows the construction of an efficient LR-like parser for visual languages of very practical interest. © 1994 ACM
A Classification Framework to Support the Design of Visual Languages
No full textAn important step in the design of visuallanguages is the specification of the graphical objects and the composition rules for constructing feasible visual sentences. The presence of different typologies of visuallanguages, each with specific graphical and structural characteristics, yields the need to have models and tools that unify the design steps for different types of visuallanguages. To this aim, in this paper we present a formal framework of visuallanguage classes. Each class characterizes a family of visuallanguages based upon the nature of their graphical objects and composition rules. The framework has been embedded in the VisualLanguage Compiler–Compiler (VLCC), a graphical system for the automatic generation of visual programming environments
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
Automatic parser generation for pictorial languages
No full textWhile in a string grammar the only possible spatial relation is the string concatenation, in a positional grammar other spatial relations can be defined and then used for describing high dimensional languages. We characterize a new class of positional grammars, the extended pLALR grammars, which can be translated into traditional LALR context free grammars with positional actions. A positional action is a procedure implementing a spatial relation. In this way, the parser for an extended pLALR language can be generated automatically by the tool Yacc with no more effort. Moreover, we show that the class of extended pLALR grammars properly contains the class of pSLR grammars for which a Yacc implementation has already been given
Framework of syntactic models for the implementation of visual languages
No full textIn this paper we present a framework of syntactic models for the definition and implementation of visual languages. We analyze a wide range of existing visual languages and, for each of them, we propose a characterization according to a syntactic model. The framework has been implemented in the Visual Language Compiler-Compiler (VLCC) system. VLCC is a practical, flexible and extensible tool for the automatic generation of visual programming environments which allows to implement visual languages once they are modeled according to a syntactic model
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
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