Aesthetics-based Graph Layout for Human Consumption

Automatic graph layout is an important and long-studied problem. The basic straight-edge graph layout problem is to find spatial positions for the nodes of an input graph that maximize some measure of desirability. When graph layout is intended for human consumption, we call this measure of desirability an aesthetic. We seek an algorithm that produces graph layouts of high aesthetic quality not only for general graphs, but also for specific classes of graphs, such as trees and directed acyclic graphs. The Aesthetic Graph Layout (AGLO) approach described in this paper models graph layout as a multiobjective optimization problem, where the value of a layout is determined by multiple user-controlled layout aesthetics. The current AGLO algorithm combines the power and flexibility of the simulated annealing approach of Davidson and Harel (1989) with the relative speed of the method of Fruchterman and Reingold (1991). In addition, it is more general, and incorporates several new layout aesthetics to support new layout styles. Using these aesthetics, we are able to produce pleasing displays for graphs on which these other methods flounder.     

The Grasper-CL graph management system

Grasper-CL is a system for manipulating and displaying graphs, and for building graph-based user interfaces for application programs. It is implemented in COMMON LISP and CLIM, and has been proven by use in a number of applications. Grasper-CL includes several advances in graph drawing. It contains a graph abstract datatype plus a comprehensive and novel language of operations on that datatype. The appearance of Grasper-CL graphs can be tailored by a wide variety of shape parameters that allow the application to customize the display of nodes and edges for different domains. Default values for shape parameters can be established at several levels. Grasper-CL employs a toolbox approach to graph layout: the system contains a suite of graph layout algorithms that can be applied individually, or in combination to produce hierarchical graph layouts. The system also contains an interactive graph browser.     

Using graph parsing for automatic graph drawing

This paper presents a procedure for automatically drawing directed graphs. Our system, Clan-based Graph Drawing Tool (CG), uses a unique clan-based graph decomposition to determine intrinsic substructures (clans) in the graph and to produce a parse tree. The tree is given attributes that specify the node layout. CG then uses tree properties with the addition of “routing nodes” to route the edges. The objective of the system is to provide, automatically, an aesthetically pleasing visual layout for arbitrary directed graphs. The prototype has shown the strengths of this approach. The innovative strategy of clan-based graph decomposition is the first digraph drawing technique to analyze locality in the graph in two dimensions. The typical approach to drawing digraphs uses a single dimension, level, to arrange the nodes     

A unifying theory of control dependence and its application to arbitrary program structures

There are several similar, but not identical, definitions of control dependence in the literature. These definitions are given in terms of control flow graphs which have had extra restrictions imposed (for example, end-reachability).We define two new generalisations of non-termination insensitive and non-termination sensitive control dependence called weak and strong control-closure. These are defined for all finite directed graphs, not just control flow graphs and are hence allow control dependence to be applied to a wider class of program structures than before.We investigate all previous forms of control dependence in the literature and prove that, for the restricted graphs for which each is defined, vertex sets are closed under each if and only if they are either weakly or strongly control-closed. Low polynomial-time algorithms for producing minimal weakly and strongly control-closed sets over generalised control flow graphs are given.This paper is the first to define an underlying semantics for control dependence: we define two relations between graphs called weak and strong projections, and prove that the graph induced by a set of vertices is a weak/strong projection of the original if and only if the set is weakly/strongly control-closed. Thus, all previous forms of control dependence also satisfy our semantics. Weak and strong projections, therefore, precisely capture the essence of control dependence in our generalisations and all the previous, more restricted forms. More fundamentally, these semantics can be thought of as correctness criteria for future definitions of control dependence.     

Parametric graph drawing

A diagram is a drawing on the plane that represents a graph like structure, where nodes are represented by symbols and edges are represented by curves connecting pairs of symbols. An automatic layout facility is a tool that receives as input a graph like structure and is able to produce a diagram that nicely represents such a structure. Many systems use diagrams in the interaction with the users; thus, automatic layout facilities and algorithms for graphs layout have been extensively studied in the last years. We present a new approach in designing an automatic layout facility. Our approach is based on a modular management of a large collection of algorithms and on a strategy that, given the requirements of an application, selects a suitable algorithm for such requirements. The proposed approach has been used for designing the automatic layout facility of Diagram Server, a network server that offers to its clients several facilities for managing diagrams     

面向对象的动态图编辑器的设计与实现

提出了一种面向对象的动态图编辑器,该动态图编辑器区别一般图编辑器的方面在于：可以根据用户的需要在任何时候动态地执行用户程序定义的方法;产生可序列化的图;编辑部分和显示部分既能合并使用也能分开使用;允许用户定义任意形状的结点和弧;具有处理无向图和有向图的双重功能。用户可以分别利用交互式编辑环境和图布局机制输入小型图和中、大型图。动态图编辑器体系结构建立在软件工程设计模式和面向对象设计思想的基础上,用ＪＡ－ＶＡ２实现。     

基于图匹配的分层布局算法

针对节点数目较大并且度数比较平均的无向图,根据分层扩展的思想,提出一种基于图匹配的分层布局算法（Graph Matching Hierarchy,GMH）。基于图匹配思想对大图进行递归化简,然后应用FR算法对最粗化图进行布局,最后利用质心布局算法对图进行扩展。实验结果表明,GMH算法能够提高可视化效率,改善布局效果,且分层布局的结果更易于理解。      

A model for generation of directed graphs of information by the directed graph of metainformation for a two-level model of information units with a complex structure

A model for generation of directed graphs of information by the directed graph of metainformation for a two-level connected directed graph model of information units is described. It can be used as a basis in computer tools for editing information with a complex structure with different levels of abstraction and invariance to technological spaces (subject domains) in a common conceptual framework for carriers of this information, making it unnecessary to organize specialized training for these carriers or to involve professional intermediaries.     

基于锁增广分段图的多线程程序死锁检测

死锁是并行程序常见的缺陷之一,动态死锁分析方法根据程序运行轨迹构建锁图、分段图等模型来检测死锁.然而,锁图及其现有的各种变型无法区分同一循环中锁授权语句的多次执行,扩展锁图中记录的锁集无法捕捉线程曾经持有而又随后释放的锁信息,分段图无法刻画锁的获取和释放操作与线程启动操作耦合而导致的段间依赖关系.上述问题导致了多种死锁...     

基于SDG故障诊断的传感器分布优化设计

故障诊断是化工企业安全生产中一项重要的工作，其诊断方法的效率主要取决于监视过程变量传感器的配置。现有的双向图的设计方法配置过程繁琐，容易出错。针对这个问题，提出一种改进的基于SDG故障诊断的计算机程序算法来设计传感器的网络分布。通过对一个化工实例的仿真研究表明，这种改进的计算机程序算法具有效率高、信息利用量大、准确率高和简单易用的特点，为将基于SDG的故障诊断的方法应用于实际控制过程提供了一种新的途径。     

Smashing peacocks further: drawing quasi-trees from biconnected components

We extend the popular force-directed approach to network (or graph) layout to allow separation constraints, which enforce a minimum horizontal or vertical separation between selected pairs of nodes. This simple class of linear constraints is expressive enough to satisfy a wide variety of application-specific layout requirements, including: layout of directed graphs to better show flow; layout with non-overlapping node labels; and layout of graphs with grouped nodes (called clusters). In the stress majorization force-directed layout process, separation constraints can be treated as a quadratic programming problem. We give an incremental algorithm based on gradient projection for efficiently solving this problem. The algorithm is considerably faster than using generic constraint optimization techniques and is comparable in speed to unconstrained stress majorization. We demonstrate the utility of our technique with sample data from a number of practical applications including gene-activation networks, terrorist networks and visualization of high-dimensional data     

Distance‐based control of formations with hybrid communication topology

In this paper, we focus on the control of multiagent formations with hybrid communication topology through a distance‐based approach. By saying hybrid topology, we mean that the communication topology contains both undirected and directed links, or the underlying graph of the formation contains both undirected and directed edges. A new type of graph, ie, hybrid graph, is introduced. We discuss the persistence of hybrid graphs and present the persistence verification strategy for hybrid graphs. It is proved that all the minimally persistent hybrid graphs can be obtained from persistent directed graphs by the operation of edge transformation. As the main result, it is shown that multiagent formations modeled by acyclic persistent hybrid graphs can be stabilized locally under distance‐based controllers.     

基于力导向模型的网络图自动布局算法综述

实现网络图形中节点和边自动布局一直是可视化研究中一个重要内容,基于力导向模型的自动布局算法则是该类研究中应用最广、文献最多的一类方法。根据研究方向出现的时间顺序,从基本模型、基于多维尺度分析的布局算法、多层迭代布局算法、非欧空间节点布局算法、受约束图形自动布局算法等五个方面对基于力引导模型的网络图自动布局算法的典型方法、研究进展、分支情况等进行了描述,并对发展前沿进行了讨论。     

Convergent drawing for mutually connected directed graphs

Directed graphs are used to represent a variety of datasets, including friendship on social networking services (SNS), pathways of genes, and citations of research papers. Graph drawing is useful in representing such datasets. At the international conference on Information Visualization (IV), we have presented a convergent edge drawing and a node layout technique for tightly and mutually connected directed graphs. The edge drawing technique in the IV paper includes three features: ordinary bundling of edges connecting pairs of node clusters, convergence of multiple bundles that connect to the same node cluster, and shape adjustment of two bundles connecting the same pair of node clusters. In this paper, we present improved node layout and edge drawing techniques, which make our edge bundling more effective. This paper also introduces a case study with a directed paper citation graph dataset.vvvvv     

Black-white pebbles and graph separation

Summary We exhibit a close relationship between two topics in computational complexity. One topic is the analysis of storage requirements for nondeterministic computations. The corresponding mathematical model is a well known black-white pebble game on directed acyclic graphs. The other topic is the search for small separators of undirected graphs. We model a dynamic version of the concept of a separator with a vertex separator game. This game is closely related to graph layout and searching problems. We show that instances of the black-white pebble game and the vertex separator game can easily be transformed into each other. As an application of this result both games are shown to be NP-complete.     

超大幅面动态生成图形的WWW发布技术

本文分析了当前WWW动态信息发布技术，针对超大幅面动态生成图形的WWW发布，提出了一种利用Win32 CGI的解决方案。在方案中将超大幅面动态生成图形划分成若干幅易于发布的小幅图形，利用Win32 CGI控制生成这些小幅图形，同时生成显示控制页面，实现在客户端浏览器中形成超大幅面动态生成图形。文中对实现中涉及到的一些主要问题给出相应的解决方案，并对该方案的应用领域进行了初步讨论。     

Searching graphs with A*: applications to job sequencing

The best-first search algorithm A* allows search graphs that are trees, directed acyclic graphs or directed graphs with cycles. In real life applications of A* the search graph is generally implemented as a tree. It is shown here that for certain well known one-machine job sequencing problems that arise in job shops, graph search is much faster than best-first tree search when problem instances are of small and medium size. Moreover, graph search uses less memory and so is able to solve larger problems. Depth-first search needs little memory, and is therefore capable in principle of solving problems of arbitrary size, but is slower than graph search by orders of magnitude for the examples that were studied     

RailwayDB: adaptive storage of interaction graphs

We are living in an ever more connected world, where data recording the interactions between people, software systems, and the physical world is becoming increasingly prevalent. These data often take the form of a temporally evolving graph, where entities are the vertices and the interactions between them are the edges. We call such graphs interaction graphs. Various domains, including telecommunications, transportation, and social media, depend on analytics performed on interaction graphs. The ability to efficiently support historical analysis over interaction graphs requires effective solutions for the problem of data layout on disk. This paper presents an adaptive disk layout called the railway layout for optimizing disk block storage for interaction graphs. The key idea is to divide blocks into one or more sub-blocks. Each sub-block contains the entire graph structure, but only a subset of the attributes. This improves query I/O, at the cost of increased storage overhead. We introduce optimal integer linear program (ILP) formulations for partitioning disk blocks into sub-blocks with overlapping and nonoverlapping attributes. Additionally, we present greedy heuristics that can scale better compared to the ILP alternatives, yet achieve close to optimal query I/O. We provide an implementation of the railway layout as part of RailwayDB—an open-source graph database we have developed. To demonstrate the benefits of the railway layout, we provide an extensive experimental evaluation, including model-based as well as empirical results comparing our approach to baseline alternatives.     

Interactive 3D Force‐Directed Edge Bundling

Interactive analysis of 3D relational data is challenging. A common way of representing such data are node‐link diagrams as they support analysts in achieving a mental model of the data. However, naïve 3D depictions of complex graphs tend to be visually cluttered, even more than in a 2D layout. This makes graph exploration and data analysis less efficient. This problem can be addressed by edge bundling. We introduce a 3D cluster‐based edge bundling algorithm that is inspired by the force‐directed edge bundling (FDEB) algorithm [ HvW09b ] and fulfills the requirements to be embedded in an interactive framework for spatial data analysis. It is parallelized and scales with the size of the graph regarding the runtime. Furthermore, it maintains the edge's model and thus supports rendering the graph in different structural styles. We demonstrate this with a graph originating from a simulation of the function of a macaque brain.