L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A Browser for Directed Graphs. Software---Practice and Experience, 17(1):61--76, 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....[35] Several extensions and variations of this approach have been introduced in the literature. A comprehensive survey is given in [1] A first extension that takes into consideration cycles and dummy nodes for large edges (i.e. edges that span more that one level) was introduced by Rowe et al. [31]. Gansner et al. 14, 15] provide a technique to draw directed graphs using a simplex based algorithm that assigns vertices to layers; at the same time, they provide an extension to the basic algorithm of Sugiyama et al. by drawing edge bends as curves. A divide and conquer approach is described ....

L. A. Rowe, M. Davis, E. Messinger, and C. Meyer. A bowser for directed graphs. Software Practice and Experience, 17(1):61--76, January 1987.

....it was also changed according to the work by Moen ( 4] It allows nodes of any shape and allows insertion deletion of nodes. 2.1. 2 Hierarchical Graphs The algorithm to represent hierarchical graphs by Sugiyama was chosen ( 8] As the original algorithm doesn t layout cycles, Rowe s suggestion ([7]) was used to temporarily invert edges. To minimize the number of edge crossings in each level an heuristics based on a combination of Gansner s ( 2] and Rowe s work was used. 2.1.3 General Graphs We have chosen to implement Kamada s algorithm for drawing general graphs ( 3] This algorithm ....

Lawrence A. Rowe, Michael Davis, Eli Messinger, Carl Meyer, Charles Spirakis, and Allen Tuan. A browser for directed graphs. Software - Practice and Experience, 17(1):61-76, January 1987.

.... have been developed for some important families of graph layouts, such as hierarchies, planar embeddings, orthogonal grids and forced directed (spring) models [1] These techniques have been incorporated in practical user interfaces that display static diagrams of relationships between objects [19, 18, 17]. Static diagrams are not completely satisfactory because in many situations, the displayed graphs can change. Three common scenarios are: Manual editing. Most interactive graph drawing systems allow users to manually insert and delete nodes and edges. Layouts must be updated dynamically to ....

L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software -- Practice and Experience, 17(1):61--76, 1987.

....be possible to allow manual improvements by the user which have to be regarded by the layouts algorithms. Related Work A general bibliography of algorithms for graph layout is given in [7] Examples of interactive graph editors which use automatic layout are Bonsai [8] COOL [9] EDGE [10] GRAB [11], ISI Grapher [12] GERM [13] and GraphED [14] They work with fixed heuristics so that they guarantee short calculation times. However, the mentioned graph editors are not flexible enough to be used as a basis for an ADL system. A different approach to GUI related layout calculation are ....

Rowe, L.A., Davis, M., Messinger, E., Meyer, C., Spirakis, C., Tuan, A.: A Browser for directed Graphs, Software - Practice and Experience 17 (1), 61-76 (1987)

....tools is very complicated because addition or displacement of even a single block may cause a need to change the placement of all diagram elements. Automatic layout of graph like structures is a well studied problem [5,6,7] and layout algorithms for entire diagrams have been known for a long time [4, 8, 9, 10, 11, 12, 13]. However, since the creation of a complex diagram is a gradual interactive process during which only fragments of diagram are presented and intermediate layouts of them are needed, fully automatic tool may produced fragment layouts that are optimal by themselves, but nevertheless, non adequate ....

L.A.Rowe, M.Davis, E.Messinger, C.Meyer, C.Spirakis, A.Tuan. A browser for directed graphs. { Software-Practice and Experience, vol. 17(1), 1987, pp. 61-76.

....for a process management tool. dotty can be controlled either through a WYSIWYG interface, or through a textual (procedural) interface. As a stand alone tool, dotty is similar in operation to other systems based on treating pictures of graphs as structured objects. GRAB, EDGE, and GraphEd [24, 22, 11] are some wellknown examples. Like these tools, dotty provides menu driven commands for loading or creating graphs, performing editing operations, and saving the changed graphs. Attributed graphs are stored in a data language that is flexible in handling attributes, so new ones can be added to ....

L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software--Practice and Experience, 17(1):61--76, Jan. 1987.

....needs. If you intend to print out the graphical display you have to use the print command of the display program AMD, see next section. 26 CHAPTER 2. USER MANUAL 2. 3 Displaying Transition Graphs The graph display algorithm implemented in AMoRE is based on the approach of Sugiyama et al. [STT81, RDM 86]: A breadth first search of the transition graph is carried out, starting with the initial state. For a back edge or a cross edge from some level of the breadth first tree to a non neighbour level, auxiliary points are introduced on each level which is crossed by the edge. Subsequently the states ....

L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Sprirakis, A. Tuan, A browser for directed graphs, Software -- Practice and Experience 17 (1986), 61--76. BIBLIOGRAPHY 135

....shell diagram graphs. The application of these algorithms to visualisation systems has recently received some attention. Some systems employ one kind of algorithm for its domain of application; for instance, Sugiyama s algorithm [7] for drawing directed graphs has been employed in many systems [8, 9, 10]. Other systems integrate many algorithms to support multi domain applications, for instance, see [11, 12, 13, 14, 15] However, the limitations on the modelling ability of classical graphs reduces the usefulness of the drawing algorithms. Unfortunately, there is little research on automatic ....

L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software Practice and Experience, 17(1):61--76, 1987.

....to the protocol as such information would effectively allow programs to differentiate between eq and equal. Another problem is that if we allowed users to create graphs, we would certainly have to devise a new layout strategy. Although some good algorithms for graph layout exist ( 2] [5]) they do not fit our needs because: ffl they aren t really designed for ordered graphs; ffl they take a nontrivial amount of time to develop the layout; and ffl they operate on fixed, not changing, graphs. Because we work in a system in which the structure of the graph may change ....

Lawrence A. Rowe, Michael Davis, Eli Messinger, Carl Meyer, Charles Spirakis, and Allen Tuan. A browser for directed graphs. Software--- Practice and Experience, 17(1):61--76, 1987.

....a challenge to every programmer. There is a growing number of systems to support this process, which can be roughly divided into two categories. Systems like LEDA [15] and graphbase [13] concentrate on the implementation of a library of graph algorithms. Systems like EDGE [16] DaVinci [7] or GRAB [17] concentrate on graph visualization and editing, and offer only limited support for implementing algorithms. There is a gap between these two categories. To program and work with graph algorithms, it is necessary to input and output graphs in a convenient way. It is obvious that a text based ....

Rowe, L.A., Davis, M., Messinger, E., Meyer, C., Spirakis, C., and Tuan, A.: A browser for directed graphs. Software Practice and Experience, 17(1) (1987) 61--76

....extraction and filtering, storage and retrieval, abstraction, queries, layout, and exploration. The G system [15] is one example, although it does not attempt to solve many of the problems that we discuss later. Recent work on graph browsers and editors also addresses several of these areas [39, 25, 27, 34]. In the remainder of this section, we define the aforementioned tasks. 4.1 Graph Filtering and Extraction A (simple) graph extractor is given a database and a set of extraction criteria as input, and produces a database graph as output. Example 4.1 In the sample database, subjects, documents, ....

....and gives rise to approximate specifications of structure that are simpler yet sufficiently accurate. 4.3.3 Graph Browser The need for graph abstraction facilities has also been recognized in several articles describing graph browsers and editors. In an article describing Graph Browser (GRAB) [39], the authors observed a property common in many function call graphs 4 : generic utility functions are called by many functions. The associated graph, therefore, has several vertices whose in degree is proportionally much higher than that of other vertices. The same point is noted 4 Each ....

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L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and Tuan A. A Browser for Directed Graphs. Software--Practice and Experience, 17(1):61--76, January 1987.

....to remove such duplicates. The next step is the invocation of the graph display part of the HYPERSOLVER. This part takes the solution of a system of equations produced by the equation solver as input. As the general graph layout algorithm, a variant of the hierarchical layout algorithm proposed in [22] is exploited. The reason to use a hierarchical layout algorithm instead of a general purpose algorithm is that most of the equations to be solved by the Solution Lemma will be hierarchical and that self reference generally occurs for a single indeterminate. Figure 5 is a good example of this. ....

L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A Browser for Directed Graphs. Software---Practice and Experience, 17(1):61--76, 1987.

....graph is an NP complete problem [23] One early heuristic solution (K. Sugiyama [41] approached the problem by ordering the graph into distinct levels and using an iterative approach to minimize the crossings between adjacent levels thus reducing the overall number of crossings. Later work [11, 35] improved this method by introducing new algorithms for partitioning the graph and reducing the edge crossings. The first step of this algorithm is to use a depth first search to identify all edges that create cycles; the cycles are then broken by reversing these edges. The next step is to ....

....into packets called chromosomes; mutation randomly alters the chromosomes. Crossovers swap correlated regions of two different chromosomes. 2.3 Graph Editors and Browsers Graph editors allow users to create and change a graph. Graph browsers allow the user to examine interactively a graph layout [18, 22, 30, 33, 35, 40]. Early graph editors browsers required the user to specify manually the layout of the nodes and edges. The GRAB system [35] introduced the idea of using a layout algorithm to generate automatically the layout. Most of the recent work in graph editors browsers incorporate layout algorithms. ....

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Rowe, L. A., Davis, M. Messinger, E. Meyer, C. A Browser for Directed Graphs, Software Practice and Experience, Vol. 17. No. 1, Pages 61-76, January 1987.

.... attributes appearing in a rule, and each edge has a distinguished vertex (the attribute of the right hand side) and two weights (support and confidence) The wide research in drawing and visualizing ordinary graphs shows that even that problem is by no means easy (see e.g. EDGE [11] DAG [4] or [15]) thus for the much harder problem of visualizing weighted hypergraphs we must be content with fairly simple solutions. We concentrate on an attribute graph model; simpler graphical alternatives include techniques such as the tree model [10, 16] The basic idea of the graph model is to represent ....

L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software---Practice and Experience, 17(1):61 -- 76, January 1987.

....can handle the case that nodes may have different sizes. The algorithm in [12] employs a different aesthetic standard. It also draws a layout with the minimum width under the adopted aesthetic standard. The algorithm in [1] can handle the case that nodes may have different sizes. The algorithms in [2, 11] are for graph layouts. All of the above mentioned algorithms are sequential. By contrast, this paper shows that the layout problem can be solved by a data parallel algorithm. The data parallel tree layout algorithm presented in this paper is motivated by the sequential tree layout algorithm in ....

L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan, A browser for directed graphs, Software---Practice and Experience 17(1) pp. 61-76 (January 1987).

....Science, 4107 Upson Hall, Cornell University, Ithaca, NY 14853, karl cs.cornell.edu 1 INTRODUCTION Graphs, consisting of a set of nodes and a set of edges, are one of the most fundamental ways of representing relationships among objects. Programs that display a set of relationships as a graph [12, 11, 14, 2, 4] have become more prevalent in recent years because of two major factors. Firstly, a person is usually able to comprehend information better when it is presented pictorially (for example a graph) rather than in textual form. This is partly due to the fact that structural properties such as ....

....goals of a particular layout algorithm. Therefore, our system should be adaptable to several different ones. In the following we describe the integration into Sugiyama s layout algorithm [13] This layout algorithm or some variation thereof is used in several systems that display directed graphs [12, 6, 4]. First we show how structural constraints are taken into account, then we use this mechanism to achieve dynamic stability. 3.1 Structural Stability The following is a description of Sugiyama s layout algorithm, which is divided into four phases: Topological Sorting: Assign nodes to levels ....

L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software---Practice and Experience, 17(1):61--76, January 1987.

.... (edge crossings, edge region crossings) The first question we address is of fundamental significance for drawing hierarchical graphs: does every planar hierarchical graph admit a planar straight line hierarchical drawing While many algorithms have been developed to draw hierarchical graphs [5, 10, 11, 23, 34, 39, 46], they all introduce bends to route the edges, and the basic problem of planar straight line drawings has not been solved completely. It has been shown by di Battista and Tamassia [2] that every planar st graph admits an upward drawing, that is, a drawing where all arcs are drawn as straight line ....

L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software -- Practice and Experience, 17(1):61--76, 1987.

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L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A Browser for Directed Graphs. Software---Practice and Experience, 17(1):61--76, 1987.

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L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis and A. Tuan, @A browser for directed graphs', Software--Practices and Experience, 17, 61--76 (1987).

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L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and Tuan A. A Browser for Directed Graphs. Software--Practice and Experience, 17(1):61--76, January 1987.

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L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software -- Practice and Experience, 17(1):61--76, 1987.

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A. Rowe, M. Davis, E. Messinger, C. Meyer, C.Spirakis, and A. Tuan. A browser for directed graphs. Software: Practice and Experience, 17(1):61--76, 1987.

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L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software -- Practice and Experience, 17(1):61--76, 1987.

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L. A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software Practice and Experience, 17(1):61--76, Jan. 1987.

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L.A. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and Tuan A. A Browser for Directed Graphs. Software--Practice and Experience, 17(1):61--76, January 1987.

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L. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software Practice and Experience, 17(1):61--76, 1987.

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L. Rowe, M. Davis, E. Messinger, C. Meyer, C. Spirakis, and A. Tuan. A browser for directed graphs. Software Practice and Experience, 190 17(1):61--76, 1987.

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