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28
TagCloud Drawing: Algorithms for Cloud Visualization
, 2007
"... Tag clouds provide an aggregate of tagusage statistics. They are typically sent as inline HTML to browsers. However, display mechanisms suited for ordinary text are not ideal for tags, because font sizes may vary widely on a line. As well, the typical layout does not account for relationships that ..."
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Cited by 77 (2 self)
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Tag clouds provide an aggregate of tagusage statistics. They are typically sent as inline HTML to browsers. However, display mechanisms suited for ordinary text are not ideal for tags, because font sizes may vary widely on a line. As well, the typical layout does not account for relationships that may be known between tags. This paper presents models and algorithms to improve the display of tag clouds that consist of inline HTML, as well as algorithms that use nested tables to achieve a more general 2dimensional layout in which tag relationships are considered. The first algorithms leverage prior work in typesetting and rectangle packing, whereas the second group of algorithms leverage prior work in Electronic Design Automation. Experiments show our algorithms can be efficiently implemented and perform well.
Using Curves to Enhance Parallel Coordinate Visualisations
"... This paper introduces a number of refinements to the Parallel Coordinates visualisation metaphor for multidimensional data. Firstly, the traditional set of polylines are replaced with a collection of smooth curves across the attribute axes, allowing individual data elements to be traced under certa ..."
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Cited by 22 (0 self)
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This paper introduces a number of refinements to the Parallel Coordinates visualisation metaphor for multidimensional data. Firstly, the traditional set of polylines are replaced with a collection of smooth curves across the attribute axes, allowing individual data elements to be traced under certain limitations; normally impossible due to the `crossing problem'. Then the notion of spreading out points on axes with a few discrete values is introduced, which leads onto a simple focus+context technique when the user selects values on such axes.
How important is the ”mental map”? — An empirical investigation of a dynamic graph layout algorithm
 Graph Drawing, volume 4372 of Lecture Notes in Computer Science
, 2006
"... Abstract. While some research has been performed on the human understanding of static graph layout algorithms, dynamic graph layout algorithms have only recently been developed sufficiently to enable similar investigations. This paper presents the first empirical analysis of a dynamic graph layou ..."
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Cited by 20 (0 self)
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Abstract. While some research has been performed on the human understanding of static graph layout algorithms, dynamic graph layout algorithms have only recently been developed sufficiently to enable similar investigations. This paper presents the first empirical analysis of a dynamic graph layout algorithm, focusing on the assumption that maintaining the “mental map ” between timeslices assists with the comprehension of the evolving graph. The results confirm this assumption with respect to some categories of tasks. 1
Notes on Large Angle Crossing Graphs
, 2010
"... A graph G is an α angle crossing (αAC) graph if every pair of crossing edges in G intersect at an angle of at least α. The concept of right angle crossing (RAC) graphs (α = π/2) was recently introduced by Didimo et al. [6]. It was shown that any RAC graph with n vertices has at most 4n −10 edges and ..."
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Cited by 12 (0 self)
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A graph G is an α angle crossing (αAC) graph if every pair of crossing edges in G intersect at an angle of at least α. The concept of right angle crossing (RAC) graphs (α = π/2) was recently introduced by Didimo et al. [6]. It was shown that any RAC graph with n vertices has at most 4n −10 edges and that there are infinitely many values of n for which there exists a RAC graph with n vertices and 4n − 10 edges. In this paper, we give upper and lower bounds for the number of edges in αAC graphs for all 0 < α < π/2. 1
The straightline RAC drawing problem is NPhard
, 2012
"... A RAC drawing of a graph is a polyline drawing in which every pair of crossing edges intersects at right angle. In this paper, we focus on straightline RAC drawings and demonstrate an infinite class of graphs with unique RAC combinatorial embedding. We employ members of this class in order toshow t ..."
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Cited by 10 (4 self)
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A RAC drawing of a graph is a polyline drawing in which every pair of crossing edges intersects at right angle. In this paper, we focus on straightline RAC drawings and demonstrate an infinite class of graphs with unique RAC combinatorial embedding. We employ members of this class in order toshow thatit is NPhardtodecide whether agraph admits a straightline RAC drawing.
On the perspectives opened by right angle crossing drawings
 In Proc. 17th Int. Symp. Graph Drawing (GD 2009), volume 5849 of LNCS
, 2010
"... Abstract. Right Angle Crossing (RAC) drawings are polyline drawings where each crossing forms four right angles. RAC drawings have been introduced because cognitive experiments provided evidence that increasing the number of crossings does not decrease the readability of the drawing if the edges cr ..."
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Cited by 9 (4 self)
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Abstract. Right Angle Crossing (RAC) drawings are polyline drawings where each crossing forms four right angles. RAC drawings have been introduced because cognitive experiments provided evidence that increasing the number of crossings does not decrease the readability of the drawing if the edges cross at right angles. We investigate to what extent RAC drawings can help in overcoming the limitations of widely adopted planar graph drawing conventions, providing both positive and negative results. First, we prove that there exist acyclic planar digraphs not admitting any straightline upward RAC drawing and that the corresponding decision problem is NPhard. Also, we show digraphs whose straightline upward RAC drawings require exponential area. Second, we study if RAC drawings allow us to draw boundeddegree graphs with lower curve complexity than the one required by more constrained drawing conventions. We prove that every graph with vertexdegree at most 6 (at most 3) admits a RAC drawing with curve complexity 2 (resp. 1) and with quadratic area. Third, we consider a natural nonplanar generalization of planar embedded graphs. Here we give bounds for curve complexity and area different from the ones known for planar embeddings.
Minimizing crossings in hierarchical digraphs with a hybridized genetic algorithm
 J. HEURISTICS
, 2006
"... Producing clear and intelligible layouts of hierarchical digraphs knows a renewed interest in information visualization. Recent experimental results show that metaheuristics are welladapted methods for this problem. In this paper, we develop a new Hybridized Genetic Algorithm for arc crossing min ..."
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Cited by 8 (2 self)
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Producing clear and intelligible layouts of hierarchical digraphs knows a renewed interest in information visualization. Recent experimental results show that metaheuristics are welladapted methods for this problem. In this paper, we develop a new Hybridized Genetic Algorithm for arc crossing minimization. It follows the basic scheme of a GA with two major differences: problembased crossovers adapted from ordering GAs are combined with a local search strategy based on averaging heuristics. Computational testing was performed on a set of 180 random hierarchical digraphs of standard sizes with various structures. Results show that the Hybridized Genetic Algorithm significantly outperforms Tabu Searchwhich is one of the best known methods for this problem and also a multistart descent except for highly connected graphs.
CFB: a call for benchmarks  for software visualization
 In 2nd IEEE Workshop of Visualizing Software for Understanding and Analysis
"... The paper argues for the need of a benchmark, or suite of benchmarks, to exercise and evaluate software visualization methods, tools, and research. The intent of the benchmark(s) must be to further and motivate research in the field of using visualization methods to support understanding and analysi ..."
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Cited by 6 (0 self)
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The paper argues for the need of a benchmark, or suite of benchmarks, to exercise and evaluate software visualization methods, tools, and research. The intent of the benchmark(s) must be to further and motivate research in the field of using visualization methods to support understanding and analysis of real world and/or large scale software systems undergoing development or evolution. The paper points to other software engineering subfields that have recently benefited from benchmarks and explains how these examples can assist in the development of a benchmark for software visualization. 1
Elements for the description of fitness landscapes associated with local operators for layered drawings of directed graphs
 METAHEURISTICS: COMPUTER DECISIONMAKING
, 2004
"... ..."
Maximizing the total resolution of graphs
 Proc. of 18th International Symposium on Graph Drawing (GD 2010) LNCS
, 2011
"... A major factor aecting the readability of a graph drawing is its resolution. In the graph drawing literature, the resolution of a drawing is either measured based on the angles formed by consecutive edges incident to a common vertex (angular resolution) or by the angles formed at edge crossings (cro ..."
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Cited by 4 (1 self)
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A major factor aecting the readability of a graph drawing is its resolution. In the graph drawing literature, the resolution of a drawing is either measured based on the angles formed by consecutive edges incident to a common vertex (angular resolution) or by the angles formed at edge crossings (crossing resolution). In this paper, we introduce the notion of total resolution, that is, the minimum of the angular and crossing resolution. To the best of our knowledge, this is the rst time where the problem of maximizing the total resolution of a graph over all its drawings is studied. The main contribution of the paper consists of drawings of asymptotically optimal total resolution for complete graphs (circular drawings) and for complete bipartite graphs (2layered drawings). In addition, we present and experimentally evaluate a forcedirected based algorithm that constructs drawings of large total resolution.