1,721,246 research outputs found
Enhancing Graph Edit Distance Computation: Stronger and Orientation-Based ILP Formulations
No full textThe graph edit distance (GED) is among the most widely used graph similarity measures in practice. It asks for a minimum cost edit path between two given labeled graphs G and H, where the edit path is defined as a sequence of operations (e.g., node and edge insertions, deletions or substitutions) that successively transform the graph G into H. In this work, we suggest a new ILP formulation (FORI) based on orienting the corresponding edge variables. Moreover, we suggest enhancing two state-of-the-art ILP formulations by incorporating additional inequalities. We theoretically compare the strength of the formulations with respect to their Linear Programming relaxations. The result is a hierarchy with (FORI) at the top. Our extensive evaluation on widely used benchmark sets shows that our improved formulations run significantly faster than the previous ones. These allow to solve to proven optimality all the reference instances from common databases, such as the IAM Graph Database, many of which were prohibitive with state-of-the-art methods. Moreover, we are able to compute the GED of a small pattern and a large graph such as CORA and PUBMED, having up to 19,717 nodes and 44,327 edges
Caesar Automatic Layout of UML Class Diagrams
No full textUML diagrams have become increasingly important in the engineering and reengineering processes for software systems. Of particular interest are UML class diagrams whose purpose is to display class hierarchies (generalizations), associations, aggregations, and compositions in one picture. The combination of hierarchical and non-hierarchical relations poses a special challenge to a graph layout tool. Commercial software typically uses Sugiyama-style methods, see, e.g., [1] that cannot properly distinguish between hierarchical and non-hierarchical relations.
The caesar garph drawing group develops and implements a library of algoirthms and data structures for graph drawing. Special emphasis is on the layout of UML class diagrams
AGD: A Library of Algorithms for Graph Drawing
No full textThe AGD library provides algorithms, data structures, and tools to create geometric representations of graphs and aims at bridging the gap between theory and practice in the area of graph drawing. It consists of C ++ classes and is built on top of the library of efficient data types and algorithms LEDA; an optional add-on to AGD requires ABACUS, a framework for the implementation of branch-and-cut algorithms, and contains implementations of exact algorithms for many NP-hard optimization problems in algorithmic graph drawing.
The fully documented library is freely available for non-commercial use at http://www.ads.tuwien.ac.at/AGD. The site also contains an online manual, link to AGD. The site also contains an online manual, links to AGD related papers, and contact information
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
Crossing-Critical Graphs and Path-Width
Full text linkThe crossing number cr( ) of a graph , is the smallest possible number of edge-crossings in a drawing of in the plane. A graph is crossing-critical if cr ( -e) ) for all edges of . G. Salazar conjectured in 1999 that crossing-critical graphs have path-width bounded by a function of their crossing number, which roughly means that such graphs are made up of small pieces joined in a linear way on small cut-sets. That conjecture was recently proved by the author [9]. Our paper presents that result together with a brief sketch of proof ideas. The main focus of the paper is on presenting a new construction of crossing-critical graphs, which, in particular, gives a nontrivial lower bound on the path-width. Our construction may be interesting also to other areas concerned with the crossing number
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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