There is an increasing demand for a computer graphics - oriented software package for graph theory teaching and research. G-Net, a department research project headed by Dr. Kunwarjit Bagga, is an effort to create a computer software that contains a graph theory database, a graph editor, and a collection of algorithms to be executed on the graphs. This thesis concentrates on the design and implementation of a graph editor - GrapliPerfect. Graphs have been widely used to model many other phenomena. In this thesis, computer generated graphics images are used to represent graphs. This modeling relation between graphs and graphics is analyzed, and its role in the design and implementation of GraphPerfect is discussed in the thesis. To enhance the friendliness of the user interface, a simplified window system is presented. / Department of Computer Science

No description available.

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 147-151). Also available online in ProQuest, free to University of Oregon users.

J.L. Marroquin. / "May, 1985." / Bibliography: p. 16. / "Advanced Research Projects Agency of the Department of Defense under Office of Naval Research Contract N00014-80-C-0505" "The author was supported by the Army Research Office under contract ARO-DAAG29-84-K-0005."

Thesis (MSc (Mathematical Sciences. Applied Mathematics))--University of Stellenbosch, 2007. / In this thesis we focus on the lower domination parameters of a graph G, denoted ¼(G), for ¼ 2 {i, ir, °}. For each of these parameters, we are interested in characterizing the structure of graphs that are critical when faced with small changes such as vertex-removal, edge-addition and edge-removal. While criticality with respect to independence and domination have been well documented in the literature, many open questions still remain with regards to irredundance. In this thesis we answer some of these questions. First we describe the relationship between transitivity and criticality. This knowledge we then use to determine under which conditions certain classes of graphs are critical. Each of the chosen classes of graphs will provide specific examples of different types of criticality. We also formulate necessary conditions for graphs to be ir-critical and ir-edge-critical.

For a graph G = (V (G), E (G)), a set S ~ V (G) dominates G if each vertex in V (G) \S is adjacent to a vertex in S. The domination number I (G) (independent domination number i (G)) of G is the minimum cardinality amongst its dominating sets (independent dominating sets). G is k-edge-domination-critical, abbreviated k-1- critical, if the domination number k decreases whenever an edge is added. Further, G is hamiltonian if it has a cycle that passes through each of its vertices. This dissertation assimilates research generated by two conjectures: Conjecture I. Every 3-1-critical graph with minimum degree at least two is hamiltonian. Conjecture 2. If G is k-1-critical, then I ( G) = i ( G). The recent proof of Conjecture I is consolidated and presented accessibly. Conjecture 2 remains open for k = 3 and has been disproved for k :::>: 4. The progress is detailed and proofs of new results are presented. / Mathematical Science / M. Sc. (Mathematics)

Orientador: Suzy Maria Lagazzi / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-21T06:51:11Z (GMT). No. of bitstreams: 1 Nunes_SilviaRegina_D.pdf: 5146653 bytes, checksum: d405a98ab664b11f55218a5cfe16e0d2 (MD5) Previous issue date: 2012 / Resumo: A pesquisa se inscreve na área da Análise de Discurso materialista e tem como objetivo a compreensão do funcionamento do infográfico nas suas formas impressa e eletrônica. A inquietação sobre os diferentes modos de leitura na contemporaneidade, que são condicionados pela circulação de materiais formulados a partir da relação entre diferentes elementos significantes, tais como a imagem, o som e a palavra, fundamentou a produção da pergunta que orienta esta pesquisa: como a leitura se organiza na textualidade espaço-temporal do discurso do infográfico? Refletimos sobre o discurso da informação e o modo como foram se constituindo, historicamente, efeitos de evidência sobre a necessidade de se informar. Compreendemos a emergência de um efeito de necessidade sobre "certa" forma de formulação para a informação que seria sustentada no efeito de evidência da estatística, do numérico. Historicizamos a constituição da infografia e apresentamos o modo como a relação entre a constituição da informação e também da informática administra sentidos para a constituição de um discurso (do) infográfico. Fizemos um trajeto pelos discursos sobre o infográfico e demos visibilidade ao modo como uma administração de sentidos sobre seu modo de formulação e circulação são determinantes para a produção de práticas de leitura sustentadas na rapidez-velocidade, no esquemático. Mostramos que o discurso sobre o infográfico mobiliza uma concepção de língua instrumental para a sustentação de um efeito de eficácia comunicativa deste objeto. Demos visibilidade a um efeito de leitura que designamos como zig zag e funil, visto que há uma organização dos elementos significantes que demanda uma leitura em ir e vir sobre o objeto analisado, um deslocamento do olhar entre estes elementos. Apresentamos como a produção de uma posição-sujeito leitor da informação infografada se constitui na relação com a textualidade infográfica. A compreensão das análises nos levou a visualizar a produção de, pelo menos, três efeitos de sentidos que se materializam simultaneamente no discurso do infográfico: o efeito de relevância, o de síntese e o de ordenação. Tais efeitos foram determinantes para darmos visibilidade ao movimento de esquematização, um duplo movimento que abriga estabilidade e deslocamento, ou seja, um ritual que administraria os modos de leitura, contudo passível de ser quebrado pela força material das relações históricas de produção dos sentidos. Apreendemos a constituição de uma geometrização do dizer no discurso do infográfico, marca fundante da ideologia da informação e reiterada nos efeitos constituídos no movimento de esquematização. Contudo, a geometrização do dizer designa também a abertura dos sentidos, funcionando como uma rede de relações heterogêneas que possibilitaria práticas de leitura em espiral. A relação entre informação-infografia, atravessada institucionalmente pelo discurso jornalístico, mostra a produção de efeitos de sentidos de produto para a informação, e circulando como sendo um produto, inevitavelmente, fica apagado seu tenso processo histórico de constituição, visto que a relação com o consumo, com a propriedade e com o consenso está fundada neste movimento. Marcado pelo determinismo informacional, o infográfico marca e mostra um específico modo de leitura, contudo, nesse mesmo movimento, esbarra no devir da abertura dos sentidos / Abstract: Current research lies within materialist Discourse Analysis and aims at understanding the function of printed and electronic infographs. The issue on contemporary different reading modes, conditioned on the circulation of material made up from the relationship between different and significant factors, such as pictures, sound and words, foregrounded the question inherent to current research. "How is reading organized within space and time textuality in the infograph discourse?" Information discourse and the manner that evidence effects on information needs were historically constructed are debated. The emergence of a necessary effect on a "certain? formulation form for information is understood. This would be foregrounded on the effect of statistical and number evidence. The constitution of the infograph is historicized and the manner the relationship between information constitution and informatics manages meanings for the formation of an infograph discourse is brought forward. Discourses on infographs have been analyzed and the mode by which a management of meaning on its formulation and circulation are determinant for the production of reading practices based on speed schemes was revealed. Discourse on infographs mobilizes a concept of instrumental language to foreground the object?s efficaciousness communicative effect. A reading effect, denominated zigzag and funnel, has also been revealed. In fact, there is an organization of significant elements that requires a forward and backward reading on the analyzed object, or rather, a displacement of sight between the elements. The production of reading subject of infograph information is related to infograph textuality. Analyses showed the production of at least three meaning effects that materialize simultaneously in the infograph discourse, namely, relevance, synthesis and ordination effects. The latter were determinant to reveal the schematization movement, a double movement with stability and displacement, or rather, a ritual that manages reading modes. It may be broken by the material forces of historical relationships of the production of meanings. The constitution of a geometrification of language in the infograph discourse has been comprehended. It is the foundation of information ideology and repeated in the effects within the schematization movement. On the other hand, the geometrification of language is an opening of meanings. It functions as a network of heterogeneous relationships that would make possible spiral reading practices. The information-infograph relationship, institutionally worked through by the journalistic discourse, shows the production of the product?s meaning effects for information. When it is spread as a product, its constitutional historical tense process is inevitably erased. This is due to its relationship with consumption, propriety and consent based on this movement. Since it is marked by informational determinism, the infograph marks and shows a specific reading mode and, through the same movement, is hindered by the opening of meaning / Doutorado / Linguistica / Doutora em Linguística

The use of ray tracing in the analysis of certain daytime ionograms recorded at Grahamstown is discussed in this thesis. A computer program has been modified and used to trace rays in the frequency range 1 - 30 MHz. Vertical, short distance oblique, and long distance oblique ionograms have been synthesized from the results and compared with experimental ionograms for Grahamstown, the Alice - Grahamstown transmission path (64 km), and the SANAE - Grahamstown transmission path (4470 km) respectively. Ray paths have been calculated and related in detail to the models of the ionosphere and geomagnetic field. The main features of the vertical and short distance oblique ionograms can, in general, be reproduced using spherically stratified ionosphere models with electron density profiles derived from vertical ionograms. A suitable model for the geomagnetic field is a tilted dipole equivalent to the actual field at Grahamstown. The two-hop mode is shown to be, usually, the lowest on the long distance oblique records. The ionosphere model is the principal limiting factor in reproducing such ionograms, and the most satisfactory results have been those obtained with a model in which electron density is assumed to vary linearly with latitude between the profiles at SANAE and Grahamstown. The promising results obtained by ray tracing with normal ionospheric conditions indicate that the method has further possibilities which could usefully be explored. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Network data are ubiquitous in modern machine learning, with tasks of interest including node classification, node clustering and link prediction being performed on diverse data sets, including protein-protein interaction networks, social networks and citation networks. A frequent approach to approaching these tasks begins by learning an Euclidean embedding of the network, to which machine learning algorithms developed for vector-valued data are applied. For large networks, embeddings are learned using stochastic gradient methods where the sub-sampling scheme can be freely chosen. This distinguishes it from the setting of traditional i.i.d data where there is essentially only one way of subsampling the data - selecting the data points uniformly and without replacement. Despite the strong empirical performance when using embeddings produced in such a manner, they are not well understood theoretically, particularly with regards to the role of the sampling scheme. Here, we develop a unifying framework which encapsulates representation learning methods for networks which are trained via performing gradient updates obtained by subsampling the network, including random-walk based approaches such as node2vec. In particular, we prove, under the assumption that the network has an exchangeable law, that the distribution of the learned embedding vectors asymptotically decouples. We characterize the asymptotic distribution of the learned embedding vectors, and give the corresponding rates of convergence, which depend on factors such as the sampling scheme, the choice of loss function, and the choice of embedding dimension. This provides a theoretical foundation to understand what the embedding vectors represent and how well these methods perform on downstream tasks; in particular, we apply our results to argue that the embedding vectors produced by node2vec can be used to perform weakly consistent community detection.

Computational creativity is an active area of research within the artificial intelligence domain that investigates what aspects of computing can be considered as an analogue to the human creative process. Computers can be programmed to emulate the type of things that the human mind can. Artificial creativity is worthy of study for two reasons. Firstly, it can help in understanding human creativity and secondly it can help with the design of computer programs that appear to be creative. Although the implementation of creativity in computer algorithms is an active field, much of the research fails to specify which of the known theories of creativity it is aligning with. The combination of computational creativity with computer generated visualisations has the potential to produce visualisations that are context sensitive with respect to the data and could solve some of the current automation problems that computers experience. In addition theories of creativity could theoretically compute unusual data combinations, or introducing graphical elements that draw attention to the patterns in the data. More could be learned about the creativity involved as humans go about the task of generating a visualisation. The purpose of this dissertation was to develop a computer program that can automate the generation of a visualisation, for a suitably chosen visualisation type over a small domain of knowledge, using a subset of the computational creativity criteria, in order to try and explore the effects of the introduction of conceptual blending techniques. The problem is that existing computer programs that generate visualisations are lacking the creativity, intuition, background information, and visual perception that enable a human to decide what aspects of the visualisation will expose patterns that are useful to the consumer of the visualisation. The main research question that guided this dissertation was, “How can criteria derived from theories of creativity be used in the generation of visualisations?”. In order to answer this question an analysis was done to determine which creativity theories and artificial intelligence techniques could potentially be used to implement the theories in the context of those relevant to computer generated visualisations. Measurable attributes and criteria that were sufficient for an algorithm that claims to model creativity were explored. The parts of the visualisation pipeline were identified and the aspects of visualisation generation that humans are better at than computers was explored. Themes that emerged in both the computational creativity and the visualisation literature were highlighted. Finally a prototype was built that started to investigate the use of computational creativity methods in the ‘variable choice’, and ‘aesthetics’ stages of the data visualisation pipeline. / School of Computing / M. Sc. (Computing)