Results 1 
9 of
9
Visualization of Graphs with Associated Timeseries Data
"... The most common approach to support analysis of graphs with associated time series data include: overlay of data on graph vertices for one timepoint at a time by manipulating a visual property (e.g. color) of the vertex, along with sliders or some such mechanism to animate the graph for other timepo ..."
Abstract

Cited by 10 (2 self)
 Add to MetaCart
The most common approach to support analysis of graphs with associated time series data include: overlay of data on graph vertices for one timepoint at a time by manipulating a visual property (e.g. color) of the vertex, along with sliders or some such mechanism to animate the graph for other timepoints. Alternatively, data from all the timepoints can be overlaid simultaneously by embedding small charts into graph vertices. These graph visualizations may also be linked to other visualizations (e.g., parallel coordinates) using brushing and linking. This paper describes a study performed to evaluate and rank graph+timeseries visualization options based on users’ performance time and accuracy of responses on predefined tasks. The results suggest that overlaying data on graph vertices one timepoint at a time may lead to more accurate performance for tasks involving analysis of a graph at a single timepoint, and comparisons between graph vertices for two distinct timepoints. Overlaying data simultaneously for all the timepoints on graph vertices may lead to more accurate and faster performance for tasks involving searching for outlier vertices displaying different behavior than the rest of the graph vertices for all timepoints. Single views have advantage over multiple views on tasks that require topological information. Also, the number of attributes displayed on nodes has a non trivial influence on accuracy of responses, whereas the number of visualizations affect the performance time.
Minimizing crossings in hierarchical digraphs with a hybridized genetic algorithm
 J. Heuristics
, 2006
"... Abstract. 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 cros ..."
Abstract

Cited by 7 (3 self)
 Add to MetaCart
Abstract. 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.
On the Hardness of OrthogonalOrder Preserving Graph Drawing
, 2009
"... There are several scenarios in which a given drawing of a graph is to be modified subject to preservation constraints. Examples include shape simplification, sketchbased, and dynamic graph layout. While the orthogonal ordering of vertices is a natural and frequently called for preservation constrai ..."
Abstract

Cited by 2 (0 self)
 Add to MetaCart
There are several scenarios in which a given drawing of a graph is to be modified subject to preservation constraints. Examples include shape simplification, sketchbased, and dynamic graph layout. While the orthogonal ordering of vertices is a natural and frequently called for preservation constraint, we show that, unfortunately, it results in severe algorithmic difficulties even for the simplest graphs. More precisely, we show that orthogonalorder preserving rectilinear and uniform edge length drawing is NPhard even for paths.
Dynamic graph drawing with a hybridized genetic algorithm
 In ACDM VI
, 2004
"... Automatic graph drawing algorithms, especially those for hierarchical digraphs, have an important place in computeraided design software or more generally in software programs where an efficient visualization tool for complex structure is required. In these cases, aesthetics plays a major role for ..."
Abstract

Cited by 2 (2 self)
 Add to MetaCart
Automatic graph drawing algorithms, especially those for hierarchical digraphs, have an important place in computeraided design software or more generally in software programs where an efficient visualization tool for complex structure is required. In these cases, aesthetics plays a major role for generating readable and understandable layouts. Besides, in an interactive approach, the program must preserve the mental map of the user between time t − 1 and t. In this paper we introduce a dynamic drawing procedure for hierarchical digraph drawing. It tends to minimize arccrossing thanks to a hybridized genetic algorithm. The hybridization consists of a local optimization step based on averaging heuristics and two problembased crossover operators. A stability constraint based on a similarity measure is used to preserve the likeness between the layouts at time t−1 and t. Computational experiments have been done with an adapted random graph generator to simulate the construction process of 90 graphs. They confirm that, because of the actual algorithm, the arc crossing number of the selected layout is close to the best layout found. We show that computation of the similarity measure tends to preserve the likeness between the two layouts. 1
InsightBased Studies for Pathway and Microarray Visualization Tools
, 2006
"... Pathway diagrams, similar to the graph diagrams using a nodelink representation, are used by biologists to represent complex interactions at the molecular level in living cells. The recent shift towards dataintensive bioinformatics and systemslevel science has created a strong need for advanced p ..."
Abstract

Cited by 2 (0 self)
 Add to MetaCart
Pathway diagrams, similar to the graph diagrams using a nodelink representation, are used by biologists to represent complex interactions at the molecular level in living cells. The recent shift towards dataintensive bioinformatics and systemslevel science has created a strong need for advanced pathway visualization tools that support exploratory data analysis. User studies suggest that an important requirement for biologists is the need to associate microarray data to pathway diagrams. A design space for visualization tools that allow analysis of microarray data in pathway context was identified for a systematic evaluation of the visualization alternatives. The design space is divided into two dimensions. Dimension 1 is based on the method used to overlay data attributes onto pathway nodes. The three possible approaches are: overlay of data on pathway nodes one data attribute at a time by manipulating a visual property (e.g. color) of the node, along with sliders or some such mechanism to animate the pathway for other timepoints. In another approach data from all the attributes in data can be overlaid simultaneously by embedding small charts (e.g.,
Organizing Search Results with a Reference Map
"... (a) reference map (entire database) (b) query hits by relevance and similarity Fig. 1. Maintaining the global organization of subsets in hierarchically clustered document collections. Abstract — We propose a method to highlight query hits in hierarchically clustered collections of interrelated items ..."
Abstract

Cited by 1 (0 self)
 Add to MetaCart
(a) reference map (entire database) (b) query hits by relevance and similarity Fig. 1. Maintaining the global organization of subsets in hierarchically clustered document collections. Abstract — We propose a method to highlight query hits in hierarchically clustered collections of interrelated items such as digital libraries or knowledge bases. The method is based on the idea that organizing search results similarly to their arrangement on a fixed reference map facilitates orientation and assessment by preserving a user’s mental map. Here, the reference map is built from an MDS layout of the items in a Voronoi treemap representing their hierarchical clustering, and we use techniques from dynamic graph layout to align query results with the map. The approach is illustrated on an archive of newspaper articles. Index Terms—Search results, mental map, voronoi treemaps, dynamic graph layout, multidimensional scaling, edge bundling. 1
OrthogonalOrdering Constraints make Graph Drawing Hard
, 2010
"... There are several scenarios in which a given drawing of a graph is to be modified subject to preservation constraints. Examples include shape simplification, sketchbased, and dynamic graph layout. While the orthogonal ordering of vertices is a natural and frequently called for preservation constrai ..."
Abstract
 Add to MetaCart
There are several scenarios in which a given drawing of a graph is to be modified subject to preservation constraints. Examples include shape simplification, sketchbased, and dynamic graph layout. While the orthogonal ordering of vertices is a natural and frequently called for preservation constraint, we show that, unfortunately, it results in severe algorithmic difficulties even for the simplest graphs. More precisely, we show that orthogonalorder preserving rectilinear, octilinear and uniform edge length drawing is N Phard even for paths. Submitted:
Considerations in Dynamic Graph Drawing: A Survey
, 2007
"... In this survey paper we discuss the considerations involved in modeling, visualising and exploring dynamic graphs—those graphs which are continually changing in structure to reflect the evolution of the system they are representing. The design of algorithms to analyse and generate visualisations of ..."
Abstract
 Add to MetaCart
In this survey paper we discuss the considerations involved in modeling, visualising and exploring dynamic graphs—those graphs which are continually changing in structure to reflect the evolution of the system they are representing. The design of algorithms to analyse and generate visualisations of dynamic graphs pose both a technical and perceptual problem. A range of additional issues beyond those encountered for static graphs are uncovered, from the need for efficient dynamic data structures and algorithms to the difficulties of keeping a visualisation understandable for the user while it is constantly changing its form.
Communicated by:
, 2012
"... We show that rectilinear graph drawing, the core problem of bendminimum orthogonal graph drawing, and uniform edgelength drawing, the core problem of forcedirected placement, are N Phard even for embedded paths if subjected to orthogonalordering constraints. Submitted: ..."
Abstract
 Add to MetaCart
We show that rectilinear graph drawing, the core problem of bendminimum orthogonal graph drawing, and uniform edgelength drawing, the core problem of forcedirected placement, are N Phard even for embedded paths if subjected to orthogonalordering constraints. Submitted: