共查询到20条相似文献,搜索用时 15 毫秒
1.
《Journal of Visual Languages and Computing》2014,25(6):912-923
This paper describes an automated tabu search based method for drawing general graph layouts with straight lines. To our knowledge, this is the first time tabu methods have been applied to graph drawing. We formulated the task as a multi-criteria optimization problem with a number of metrics which are used in a weighted fitness function to measure the aesthetic quality of the graph layout. The main goal of this work is to speed up the graph layout process without sacrificing layout quality. To achieve this, we use a tabu search based method that goes through a predefined number of iterations to minimize the value of the fitness function. Tabu search always chooses the best solution in the neighbourhood. This may lead to cycling, so a tabu list is used to store moves that are not permitted, meaning that the algorithm does not choose previous solutions for a set period of time. We evaluate the method according to the time spent to draw a graph and the quality of the drawn graphs. We give experimental results applied on random graphs and we provide statistical evidence that our method outperforms a fast search-based drawing method (hill climbing) in execution time while it produces comparably good graph layouts. We also demonstrate the method on real world graph datasets to show that we can reproduce similar results in a real world setting. 相似文献
2.
We obtain bounds for the coloring numbers of products of trees for three closely related types of colorings: acyclic, distance 2, and L(2,1). 相似文献
3.
We show that the problem of determining whether a tree can be drawn so that it is the Euclidean minimum spanning tree of the locations of its vertices is NP-hard.Partially written while this author was visiting the University of Newcastle. 相似文献
4.
We present an algorithm for the layout of undirected compound graphs, relaxing restrictions of previously known algorithms in regards to topology and geometry. The algorithm is based on the traditional force-directed layout scheme with extensions to handle multi-level nesting, edges between nodes of arbitrary nesting levels, varying node sizes, and other possible application-specific constraints. Experimental results show that the execution time and quality of the produced drawings with respect to commonly accepted layout criteria are quite satisfactory. The algorithm has also been successfully implemented as part of a pathway integration and analysis toolkit named PATIKA, for drawing complicated biological pathways with compartmental constraints and arbitrary nesting relations to represent molecular complexes and various types of pathway abstractions. 相似文献
5.
Pradipta Prometheus Mitra 《Information Processing Letters》2004,91(4):163-169
The symmetry number of a tree is defined as the number of nodes of the maximum subtree of the tree that exhibits axial symmetry. Chin and Yen have presented an algorithm for solving the problem of finding the symmetry number of unrooted unordered trees in time O(n4). In this paper we present an improved algorithm for solving the symmetry number problem on trees that runs in time O(n3). We also show that our algorithm needs O(n2logn) time for trees with bounded degrees. 相似文献
6.
Fabrizio Frati 《Information Processing Letters》2009,109(6):301-307
In [A. García, C. Hernando, F. Hurtado, M. Noy, J. Tejel, Packing trees into planar graphs, J. Graph Theory (2002) 172-181] García et al. conjectured that for every two non-star trees there exists a planar graph containing them as edge-disjoint subgraphs. In this paper we prove the conjecture in the case in which one of the trees is a spider tree. 相似文献
7.
Structural scheme design of shear wall structures is important because it is the first stage that guides the project along its entire structural design process and significantly impacts the subsequent design stages. Design methods for shear wall layouts based on deep generative algorithms have been proposed and achieved some success. However, current generative algorithms rely on pixel images to design shear wall layouts, which have many model parameters and require intensive calculations. Moreover, it is challenging to use pixel image-based methods to reflect the topological characteristics of structures and connect them with the subsequent design stages. The above defects can be effectively solved by representing a shear wall structure in graph data form and adopting graph neural networks (GNNs), which have a robust topological-characteristic-extraction capability. However, there is no existing research using GNN methods in the design of shear wall structures owing to the lack of graph representation methods and high-quality structural graph data for shear walls. Therefore, this study develops an intelligent design method for shear wall layouts based on GNNs. Two graph representation methods for a shear wall structure—graph edge representation and graph node representation—are examined. A data augmentation method for shear wall structures in graph data form is established to enhance the universality of the GNN performance. An evaluation method for both graph representation methods is developed. Case studies show that the shear wall layout designed using the established GNN method is highly similar to the design by experienced engineers. 相似文献
8.
Visualization is crucial to the effective analysis of biological pathways. A poorly laid out pathway confuses the user, while a well laid out one improves the user’s comprehension of the underlying biological phenomenon.We present a new, elegant algorithm for layout of biological signaling pathways. Our algorithm uses a force-directed layout scheme, taking into account directional and rectangular regional constraints enforced by different molecular interaction types and subcellular locations in a cell. The algorithm has been successfully implemented as part of a pathway visualization and analysis toolkit named Patika, and results with respect to computational complexity and quality of the layout have been found satisfactory. The algorithm may be easily adapted to be used in other applications with similar conventions and constraints as well.Patika version 1.0 beta is available upon request at http://www.patika.org. 相似文献
9.
Complete characterizations are given for those trees that can be drawn as either the relative neighborhood graph, relatively closest graph, Gabriel graph, or modified Gabriel graph of a set of points in the plane. The characterizations give rise to linear-time algorithms for determining whether a tree has such a drawing; if such a drawing exists one can be constructed in linear time in the real RAM model. The characterization of Gabriel graphs settles several conjectures of Matula and Sokal [17].This research was conducted while the author was at the School of Computer Science of McGill University. Research supported in part by NSERC and FCAR.This work was done when this author was visiting the School of Computer Science of McGill University.This work was done when this author was visiting the School of Computer Science of McGill University. 相似文献
10.
Jean G. Vaucher 《Software》1980,10(7):553-561
A pleasing layout of printed tree structures is difficult to achieve automatically. The paper points out three main problems. First, the horizontal position of a node on the printed page depends on global consideration of the position of other nodes; secondly, the physical characteristics of printers require scanning the tree in left-to-right top-to-bottom sequence; finally, page overflow for wide trees must be handled. These problems are illustrated by analysing the shortcomings of a simple printing algorithm. A suitable general binary tree printing algorithm is presented and its adaptation to other types of trees is shown. 相似文献
11.
Chan 《Algorithmica》2008,34(1):1-13
Abstract. We present several simple methods to construct planar, strictly upward, strongly order-preserving, straight-line drawings
of any n -node binary tree. In particular, it is shown that O(n
1+ɛ
) area is always sufficient for an arbitrary constant ɛ>0 . 相似文献
12.
Very recently, Chen and Chen [Y. Chen, Y. Chen, A new tree inclusion algorithm, Information Processing Letters 98 (2006) 253-262] gave a new algorithm for the tree inclusion problem, which requires O(|T|×min{depth(P),|leaves(P)|}) time and no extra space. In this Note, we show that there are flaws in their time-complexity analysis by presenting two counterexamples. We also give an example to show that the worst-case time complexity of their algorithm is non-polynomial. Consequently, the asymptotically most efficient algorithm for the tree inclusion problem is the former algorithm in [W. Chen, More efficient algorithm for ordered tree inclusion, Journal of Algorithms 26 (1998) 370-385]. 相似文献
13.
王立娟 《数码设计:surface》2008,(3):7-8
设计美学是将设计和美学融会贯通成为一种新的学科理论。设计与美学的融合使设计进入了一个新的艺术境界。优秀的设计作品需要符合很多的条件才可以是美的:设计应该符合人的心理享受;设计要美就要有创新;真正美的东西不会随着时间的消逝而逊色;设计语言简洁,却蕴涵深刻内容,达到内容与形式完美的统一;真正美的东西是被大众接受的。 相似文献
14.
张兵 《数码设计:surface》2012,(6):73-75
以西方美学中的"审美移情"理论为参考,从影响电影海报设计的情感、图形、色彩等因素入手,分析电影海报设计中的给予性、象征性、拟人性、消融性等特征。以美国优秀电影海报设计作品为例,论述电影海报设计中"审美移情"产生的辩证关系,探究海报艺术的精神内涵,从而在电影与观众之间架构起视觉与心灵沟通的桥梁。 相似文献
15.
An interactive computer program is described for layout planning. This program is a construction routine. It is written in BASIC and has been tested on an Apple II microcomputer. The program generates multi-story layouts of up to three floors with sixty-four departments per floor. 相似文献
16.
刘春丽 《数码设计:surface》2012,(6):36-38
禅宗的美学智慧来源于儒家、道家和佛教的美学,它所蕴含的顿悟见性的审美思维,尊重自然、注重内在的艺术境界直接或间接的影响着人们对设计的审美。文章通过对禅宗美学思想的研究,希望为中国设计提供可用的设计理念。 相似文献
17.
版面分割是版面分析的重要组成部分,经过大量的研究,如今已到了一个比较成熟的阶段。对基于连通域的版面分割算法进行了改进,能有效快速地分割较为复杂的版面图像,同时有效减少原有算法中阈值引起的分割错误的情况。先对文本图像进行单个字体的区域扩充,使后续的连通间距统计更为准确和方便,再通过连通间距的统计对图像进行模糊整合,进行文本图像的连通区域分割。实验结果表明,改进的基于连通域的算法分割版面准确,速度快,适用范围广,对于较为复杂的版面分割更具有优越性。 相似文献
18.
In this note we observe that the problem of mixed graph coloring can be solved in linear time for trees, which improves the quadratic algorithm of Hansen et al. [P. Hansen, J. Kuplinsky, D. de Werra, Mixed graph colorings, Math. Methods Oper. Res. 45 (1997) 145-160]. 相似文献
19.
Multimedia layout adaptation through grammatical specifications 总被引:1,自引:0,他引:1
Online multimedia presentations, such as news, need to be constantly updated. Increasing demands are also being made for accessing online multimedia documents from mobile devices such as PDAs. There is an urgent need for a sound but practical formalism that supports automatic adaptation to the change of media content, display environments, and user intention. This paper presents a visual language approach to the layout adaptation of multimedia objects. The underlying theory of our approach is a context-sensitive graph grammar formalism enriched with facilities for spatial representation and specification. The paper focuses on the issues and techniques for size adaptation and style adaptation in response to the change of device requirements and user interactions.Published online: 2 February 2005
Correspondence to: Kang Zhang 相似文献
20.
The complexity of various membership problems for tree automata on compressed trees is analyzed. Two compressed representations are considered: dags, which allow to share identical subtrees in a tree, and straight-line context-free tree grammars, which moreover allow to share identical intermediate parts in a tree. Several completeness results for the classes NL, P, and PSPACE are obtained. Finally, the complexity of the evaluation problem for (structural) XPath queries on trees that are compressed via straight-line context-free tree grammars is investigated. 相似文献