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GRASP and path relinking for 2layer straight line crossing minimization
 INFORMS Journal on Computing
, 1999
"... ABSTRACT — In this paper, we develop a greedy randomized adaptive search procedure (GRASP) for the problem of minimizing straightline crossings in a 2layer graph. The procedure is fast and is particularly appealing when dealing with lowdensity graphs. When a modest increase in computational time ..."
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Cited by 101 (19 self)
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ABSTRACT — In this paper, we develop a greedy randomized adaptive search procedure (GRASP) for the problem of minimizing straightline crossings in a 2layer graph. The procedure is fast and is particularly appealing when dealing with lowdensity graphs. When a modest increase in computational time is allowed, the procedure may be coupled with a path relinking strategy to search for improved outcomes. Although the principles of path relinking have appeared in the tabu search literature, this search strategy has not been fully implemented and tested. We perform extensive computational experiments with more than 3,000 graph instances to first study the effect of changes in critical search parameters and then to compare the efficiency of alternative solution procedures. Our results indicate that graph density is a major influential factor on the performance of a solution procedure. Laguna and Martí / 2 The problem of minimizing straightline crossings in layered graphs has been the subject of study for at least 17 years, beginning with the Relative Degree Algorithm introduced by Carpano [2]. The problem consists of aligning the two shores V1 and V2 of a bipartite graph G = (V1, V2, E) on two parallel straight lines (layers) such that the number of crossing between the edges in E is minimized
StraightLine Drawing Algorithms for Hierarchical Graphs and Clustered Graphs
 Algorithmica
, 1999
"... Hierarchical graphs and clustered graphs are useful nonclassical graph models for structured relational information. Hierarchical graphs are graphs with layering structures; clustered graphs are graphs with recursive clustering structures. Both have applications in CASE tools, software visualizatio ..."
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Cited by 66 (12 self)
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Hierarchical graphs and clustered graphs are useful nonclassical graph models for structured relational information. Hierarchical graphs are graphs with layering structures; clustered graphs are graphs with recursive clustering structures. Both have applications in CASE tools, software visualization, and VLSI design. Drawing algorithms for hierarchical graphs have been well investigated. However, the problem of straightline representation has not been solved completely. In this paper, we answer the question: does every planar hierarchical graph admit a planar straightline hierarchical drawing? We present an algorithm that constructs such drawings in linear time. Also, we answer a basic question for clustered graphs, that is, does every planar clustered graph admit a planar straightline drawing with clusters drawn as convex polygons? We provide a method for such drawings based on our algorithm for hierarchical graphs.
SelfOrganizing Graphs  A Neural Network Perspective of Graph Layout
 In Neural Computers, 393–406, ECKMILLER
, 1998
"... The paper presents selforganizing graphs, a novel approach to graph layout based on a competitive learning algorithm. This method is an extension of selforganization strategies known from unsupervised neural networks, namely from Kohonen's selforganizing map. Its main advantage is that it is ..."
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Cited by 15 (0 self)
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The paper presents selforganizing graphs, a novel approach to graph layout based on a competitive learning algorithm. This method is an extension of selforganization strategies known from unsupervised neural networks, namely from Kohonen's selforganizing map. Its main advantage is that it is very flexibly adaptable to arbitrary types of visualization spaces, for it is explicitly parameterized by a metric model of the layout space. Yet the method consumes comparatively little computational resources and does not need any heavyduty preprocessing. Unlike with other stochastic layout algorithms, not even the costly repeated evaluation of an objective function is required. To our knowledge this is the first connectionist approach to graph layout. The paper presents applications to 2Dlayout as well as to 3Dlayout and to layout in arbitrary metric spaces, such as networks on spherical surfaces. 1 Introduction Automatic layout techniques are a crucial component for any application which...
Visual Overviews for Discovering Key Papers and Influences Across Research Fronts
"... Abstract: Gaining a rapid overview of an emerging scientific topic, sometimes called research fronts, is an increasingly common task due to the growing amount of interdisciplinary collaboration occurring across fields. Visual overviews that show temporal patterns of paper publication and citation li ..."
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Cited by 10 (7 self)
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Abstract: Gaining a rapid overview of an emerging scientific topic, sometimes called research fronts, is an increasingly common task due to the growing amount of interdisciplinary collaboration occurring across fields. Visual overviews that show temporal patterns of paper publication and citation links among papers can help researchers and analysts to see the rate of growth of topics, identify key papers, and understand influences across subdisciplines. This paper applies a novel network visualization tool based on meaningful layouts of nodes to present research fronts and show citation links that indicate influences across research fronts. The twodimensional layouts with multiple regions and user control of link visibility enable rapid exploration. We assess the value of our tool for this application by conducting a case study with six domain experts over a fourmonth period. The main benefits were being able (1) to easily identify key papers and see the increasing number of papers within a research front and (2) to quickly see the strength and direction of influence across related research fronts.
Competitive Learning of Network Diagram Layout
 Proc.VL'981998 IEEE Symposium on Visual Languages
, 1998
"... For applications which generate diagrammatic representations automatic layout techniques are a crucial component. Since graphlike network diagrams are among the most commonly used and most important types of diagrammatic displays, layout techniques for graphs have been extensively studied. However, ..."
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Cited by 3 (0 self)
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For applications which generate diagrammatic representations automatic layout techniques are a crucial component. Since graphlike network diagrams are among the most commonly used and most important types of diagrammatic displays, layout techniques for graphs have been extensively studied. However, a problem with current graph layout methods which are capable of producing satisfactory results for a wide range of graphs is that they often put an extremely high demand on computational resources. This paper introduces a new layout method that consumes only little computational resources and does not need any heavyduty preprocessing. Unlike other declarative layout algorithms not even the costly repeated evaluation of an objective function is required. The method presented is based on a competitive learning algorithm which is an extension of selforganization strategies known from unsupervised neural networks. 1 Introduction For applications which generate diagrammatic representations a...
Automatic Layout of Diagrams in Rational Rose
, 1998
"... : A general overview of the problem of automatically generating aesthetically pleasing drawings of graphs is presented. Requirements particular to diagrams in Rational Rose is discussed. The Sugiyama layout algorithm and the Spring Embedder algorithm together with a number of proposed modifications ..."
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Cited by 1 (0 self)
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: A general overview of the problem of automatically generating aesthetically pleasing drawings of graphs is presented. Requirements particular to diagrams in Rational Rose is discussed. The Sugiyama layout algorithm and the Spring Embedder algorithm together with a number of proposed modifications and improvements to these algorithms are discussed. Examples of drawings generated by these algorithms are presented. Automatic layout of diagrams through the use of genetic algorithms is also discussed. Supervisor: Gunnar Blomberg, Rational Software Scandinavia AB Examiner: Mats Nordstrm, Computing Science Dept., Uppsala University Passed: Contents 1 Introduction 1 1.1 Definition of Terms 2 1.2 Background 3 1.3 Problem Description 4 1.4 General Difficulties 6 2 Different Approaches 7 2.1 Algorithmic Approach 7 2.2 Declarative Approach 8 3 Examples of Algorithmic Approaches 9 3.1 Sugiyama Algorithm 9 3.1.1 Phase 1 Revisited  Preprocessing 10 3.1.2 Phase 2 Revisited  Edge Crossing Mini...
Graph Interaction through DynamicsBased Skeletal Animation
, 2003
"... Skeletal animation is a concept that has been used in the areas of motion pictures and computer games to create realistic motion for the animation of articulated characters. Recent work has applied skeletal animation techniques from inverse kinematics to the field of graph interaction. The previou ..."
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Skeletal animation is a concept that has been used in the areas of motion pictures and computer games to create realistic motion for the animation of articulated characters. Recent work has applied skeletal animation techniques from inverse kinematics to the field of graph interaction. The previous work introduced an interesting idea suggesting a skeletal graph interaction system would be intuitive and natural. However, due to problems with the skeletal animation techniques used, the benefits of the system were limited. This thesis investigates the use of a new dynamicsbased technique previously used in the area of skeletal animation for graph interaction. The motivation for this work was to improve upon the previous work by providing a skeletal graph interaction system that reduces the difficulty and time taken in navigating the graph and increases the amount of information that can be interpreted and understood. We have adapted this technique and implemented it in a graph interaction environment allowing the user to drag nodes of the skeleton in order to manipulate the layout of the graph. The graph reacts to the user movement while maintaining the physical constraints placed upon it by the skeletal metaphor. We have also conducted a user study, the results of which confirm the usefulness of both this new technique and the skeletal metaphor in aiding the user’s understanding of a graph. ii I would like to express my gratitude to: Acknowledgements • Damian Merrick, for providing a huge amount of support, advice and encouragement at every stage throughout the year. • Masahiro Takatsuka, for his everpresent ideas and advice. • The rest of the Information Visualisation Research Group, for their suggestions and discussions about the project. • All those who participated in the user study. • Mum and Dad, for always supporting me. • Brian, Cassie & Tanya for providing many distractions and keeping me sane. • All the guys in G28, for making Computer Science Honours such an enjoyable and unforgettable experience. iii
VISUALIZING & EXPLORING NETWORKS USING SEMANTIC SUBSTRATES
, 2008
"... Visualizing and exploring network data has been a challenging problem for HCI (HumanComputer Interaction) Information Visualization researchers due to the complexity of representing networks (graphs). Research in this area has concentrated on improving the visual organization of nodes and links acc ..."
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Visualizing and exploring network data has been a challenging problem for HCI (HumanComputer Interaction) Information Visualization researchers due to the complexity of representing networks (graphs). Research in this area has concentrated on improving the visual organization of nodes and links according to graph drawing aesthetics criteria, such as minimizing link crossings and the longest link length. Semantic substrates offer a different approach by which node locations represent node attributes. Users define semantic substrates for a given dataset according to the dataset characteristics and the questions, needs, and tasks of users. The substrates are typically 25 nonoverlapping rectangular regions that meaningfully lay out the nodes of the network, based on the node attributes. Link visibility filters are provided to enable users to limit link visibility to those within or across regions. The reduced clutter and visibility of only selected links are designed to help users find meaningful relationships. This dissertation presents 5 detailed case studies (3 longterm and 2 shortterm) that report on sessions with professional users working on their own datasets using successive versions of the NVSS (Network Visualization by Semantic Substrates,
Experimenting with Layout and Notation in UML Diagrams
"... This paper summarises an empirical research project that is investigating the impact of UML diagram notation and layout characteristics. The goal is to improve the effectiveness of these diagrams by identifying factors that assist human comprehension. 1. ..."
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This paper summarises an empirical research project that is investigating the impact of UML diagram notation and layout characteristics. The goal is to improve the effectiveness of these diagrams by identifying factors that assist human comprehension. 1.