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Jordan, Stephen Andrew. "Epidemiology and etiology of Eutypa dieback of grapevine and partial characterization of Eutypella vitis, a new pathogen of grapevine." Diss., Connect to online resource - MSU authorized users, 2008.
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Melo, Henrique Alves de. "Euler's formula in the plan and for polyhedra." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11431.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorPolyhedra are geometric solids formed by a finite number of polygons they can be convex or non-convex, regular or not regular. This work we make three demonstrations of Eulerâs theorem for polyhedra in one plane being used graphs. We will adopt preliminary definitions of polygons, polyhedra and graphs and make a brief study of the theorem before the demonstrations analysis when the theorem is valid and what conditions exist polyhedra, since the theorem is accepted. The work brings some applications in the form of questions in the theory presented.
Os poliedros sÃo sÃlidos geomÃtricos formados por uma quantidade finita de polÃgonos. Eles podem ser convexos ou nÃo convexos, regulares ou nÃo regulares . Neste trabalho fazemos trÃs demonstraÃÃes do teorema de Euler para poliedros no plano, sendo uma utilizado grafos. Adotaremos definiÃÃes preliminares de polÃgonos, poliedros e grafos e faremos um breve estudo do teorema antes das demonstraÃÃes analisado quando o teorema à valido em quais condiÃÃes existem os poliedros, uma vez que o teorema à aceito. O trabalho traz algumas aplicaÃÃes em forma de questÃes da teoria apresentada.
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Strydom, Janéne. "Canopy manipulation practices for optimum colour of redglobe (V.Vinifera L.) /." Link to the online version, 2006. http://hdl.handle.net/10019/1228.
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Nieuwoudt, Tania. "Packaging of table grapes for exports from SA : a comparative study." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96846.
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Thesis (MComm)--Stellenbosch University, 2015.ENGLISH ABSTRACT: Table grapes are the second-largest contributor to the perishable product export in South Africa. The table grape industry also experienced considerable growth in the past ten years. The industry contributes toward employment in South Africa. The South African table grape industry experiences quality-related problems with exporting table grapes to the European market. Examples of quality related problems can range from chemical damage, chilling injury/freezing damage, heavy bruising and decay. A great amount of table grapes is basically wasted. The postharvest loss of table grapes during transportation can range from 1%-25% per day depending on the degree of temperature fluctuation. Therefore, it is important to minimize waste and increase the export volumes in order to utilise the potential profit possibilities. Based on data analysis for this case, results indicated that packaging is preventing cool air from flowing through the pallet during transportation and preventing the table grapes to cool evenly. The fluctuation in temperature contributes to the qualityrelated problems of these table grapes. The primary research goal is to identify packaging-related problems and propose possible solutions to improve the packaging-related conditions in which table grapes arrive at the destination. This study therefore investigated and evaluated the performance of the current packaging system of table grapes within a South African context for exporting to Europe for a specific case. Further analyses of the data received from Dole South Africa, a fruit marketing and distribution company, revealed that the following two types of packaging showed serious quality-related problems: 1) A04I: The 4.5kg box with the grapes in plastic bags. 2) A05E: The 5kg box with 500g punnets (10 x 500g punnets). A questionnaire combining with the Packaging Portfolio Evaluation Model and the Packaging Scorecard was developed and used to evaluate the two identified packaging systems in the following stages: Stage 1: Development of a new questionnaire by combining the Packaging Portfolio Evaluation Model and the Packaging Scorecard. Stage 2: Survey with the questionnaire developed in Stage 1. The identified types of packaging were evaluated with a new questionnaire with specific criteria. Members of the table grape supply chain from the farmer in South Africa to consumer in Sweden were used during the evaluation process. Descriptive statistics were calculated for each criteria or question in order to describe the performance and importance of the different packaging criteria. Data were also analysed with the use of box plots. The box plots and data visualisation methods were used to make conclusions and recommendations regarding the different categories of each type of packaging. It was clear that the major problem areas of both packaging systems involved were related to the environmental aspect of the packaging. The marketing and the logistics of the plastic bag also underperformed. However, individual criteria regarding the other business areas can also be improved. Possible solutions to these problem areas are also suggested in this thesis. The possible solutions include the Tali Grape Basket, Perforated Plastic Liners, New Generation Pack (NGP), Vinguard TM , Easypunnet and the Sulphur Dioxide Liner Bag.
AFRIKAANSE OPSOMMING: Tafeldruiwe is die tweede grootste bydraende faktor tot bederfbare produkuitvoere in Suid-Afrika. Die tafeldruifindustrie het ook aansienlike groei die afgelope tien jaar beleef. Die industrie dra tot werkskepping in Suid-Afrika by. Die Suid-Afrikaanse tafeldruifindustrie ervaar kwaliteitsverwante probleme met die uitvoer van tafeldruiwe na die Europese mark. Voorbeelde van hierdie kwaliteitsverwante probleme kan wissel van chemiese skade, koueskade / vries skade, swaar kneusing en bederf. ‘n Groot hoeveelheid tafeldruiwe word vermors. Die oes verlies van tafeldruiwe tydens vervoer kan wissel van 1% -25% per dag, afhangende van die mate van temperatuur verandering. Daarom is dit belangrik om vermorsing te beperk en uitvoerhoeveelhede te verhoog om sodoende potensiële winsmoontlikhede te benut. Volgens data-analise blyk dit dat huidige verpakking tans verhoed dat koel lug tydens die vervoer van die produk deur die palet vloei, en dit veroorsaak dat die tafeldruiwe nie eweredig afkoel nie. Die wisseling in temperatuur dra grootliks tot die kwaliteitsverwante probleme van die tafeldruiwe by. Die primêre navorsingsdoelwit is om die verpakkingsverwante probleme te identifiseer en moontlike oplossings voor te stel om sodoende die toestand te verbeter waarin tafeldruiwe by die eindbestemming aankom. Daarom ondersoek en evalueer hierdie studie die prestasie van die huidige verpakkingsisteem van tafeldruiwe binne ʼn Suid-Afrikaanse konteks vir uitvoere na Europa; met betrekking tot ʼn spesifieke situasie. Verdere analise van data soos ontvang vanaf Dole Suid-Afrika, ‘n vrugtebemarkingsen verspreidingsmaatskappy, het getoon dat ernstige kwaliteitsverwante probleme veral by die volgende twee tipes verpakkingsisteme voorkom: 1) A04I: Die 4.5kg karton met druiwe in plastieksakkies. 2) A05E: Die 5kg karton met 500g bakkies (10 x 500g bakkies). ʼn Vraelys, gebaseer op die kombinasie van die Verpakkingportefeulje Evalueringsmodel model en die Verpakkingstelkaart, is ontwikkel en gebruik om die bogenoemde verpakkingsisteme te evalueer en wel in die volgende fases: Fase 1: Ontwikkeling van ʼn gekombineerde Verpakkingsportefeulje Evalueringsmodel en die Verpakkingstelkaart tot ʼn nuwe vraelys. Fase 2: Opname met die vraelys soos ontwikkel in Fase 1. Die twee geïdentifiseerde tipes verpakking is geëvalueer met die nuwe vraelys met spesifieke kriteria. Die lede van die tafeldruiwe voorsieningsketting van die boer in Suid-Afrika tot die verbruiker in Swede is gebruik tydens die evaluasieproses. Beskrywende statistiek vir elke kriteria of vraag was bereken sodat die prestasie en belangrikheid van die verskillende verpakkingskriteria beskryf kan word. Data was ook beskryf met behulp van ‘n houer-en-puntstipping. Data visualiseringmetodes en die houer-en-puntstippings was gebruik om gevolgtrekkings en aanbevelings rakende die verskillende kategorieë van die tipes verpakking te maak. Dit was duidelik dat die omgewingsaspek van beide tipes verpakking ‘n groot probleem was. Die bemarking en logistiek van die plastieksakkie het ook onderpresteer. Individuele kriteria van ander besigheidsareas kan egter ook verbeter word. Moontlike oplossings vir hierdie probleem-areas word ook in hierdie tesis aangedui. Die moontlike oplossings sluit die “Tali Grape Basket”, “Perforated Plastic Liners”, “New Generation Pack (NGP)”, “Vinguard TM ”, “Easypunnet” en die “Sulphur Dioxide Liner Bag” in
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Das, Sarma Atish. "Algorithms for large graphs." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34709.
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Sedgwick, Laura J. "Certificates for undirected graphs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ34041.pdf.
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White, David H. "Generative models for graphs." Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516724.
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Preen, James. "Structure theorems for graphs." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357965.
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Liebers, Annegret. "Methods for Planarizing Graphs." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8989124.
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Zelke, Mariano. "Algorithms for streaming graphs." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2009. http://dx.doi.org/10.18452/15912.
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Für einen Algorithmus zum Lösen eines Graphenproblems wird üblicherweise angenommen, dieser sei mit wahlfreiem Zugriff (random access) auf den Eingabegraphen G ausgestattet, als auch mit einem Arbeitsspeicher, der G vollständig aufzunehmen vermag. Diese Annahmen erweisen sich als fragwürdig, wenn Graphen betrachtet werden, deren Größe jene konventioneller Arbeitsspeicher übersteigt. Solche Graphen können nur auf externen Speichern wie Festplatten oder Magnetbändern vorrätig gehalten werden, auf denen wahlfreier Zugriff sehr zeitaufwändig ist. Um riesige Graphen zu bearbeiten, die auf externen Speichern liegen, hat Muthukrishnan 2003 das Modell eines Semi-Streaming Algorithmus vorgeschlagen. Dieses Modell beschränkt die Größe des Arbeitsspeichers und verbietet den wahlfreien Zugriff auf den Eingabegraphen G. Im Gegenteil wird angenommen, die Eingabe sei ein Datenstrom bestehend aus Kanten von G in beliebiger Reihenfolge. In der vorliegenden Dissertation entwickeln wir Algorithmen im Semi-Streaming Modell für verschiedene Graphenprobleme. Für das Testen des Zusammenhangs und der Bipartität eines Graphen, als auch für die Berechnung eines minimal spannenden Baumes stellen wir Algorithmen vor, die asymptotisch optimale Laufzeiten erreichen. Es ist bekannt, dass kein Semi-Streaming Algorithmus existieren kann, der ein größtes gewichtetes Matching in einem Graphen findet. Für dieses Problem geben wir den besten bekannten Approximationsalgorithmus an. Schließlich zeigen wir, dass sowohl ein minimaler als auch ein maximaler Schnitt in einem Graphen nicht von einem Semi-Streaming Algorithmus berechnet werden kann. Für beide Probleme stellen wir randomisierte Approximationsalgorithmen im Semi-Streaming Modell vor.An algorithm solving a graph problem is usually expected to have fast random access to the input graph G and a working memory that is able to store G completely. These powerful assumptions are put in question by massive graphs that exceed common working memories and that can only be stored on disks or even tapes. Here, random access is very time-consuming. To tackle massive graphs stored on external memories, Muthukrishnan proposed the semi-streaming model in 2003. It permits a working memory of restricted size and forbids random access to the input graph. In contrast, the input is assumed to be a stream of edges in arbitrary order. In this thesis we develop algorithms in the semi-streaming model approaching different graph problems. For the problems of testing graph connectivity and bipartiteness and for the computation of a minimum spanning tree, we show how to obtain running times that are asymptotically optimal. For the problem of finding a maximum weighted matching, which is known to be intractable in the semi-streaming model, we present the best known approximation algorithm. Finally, we show the minimum and the maximum cut problem in a graph both to be intractable in the semi-streaming model and give semi-streaming algorithms that approximate respective solutions in a randomized fashion.
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Zellagui, Soumia. "Reengineering Object Oriented Software Systems for a better Maintainability." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS010/document.
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Les systèmes logiciels existants représentent souvent des investissements importants pour les entreprises qui les développent avec l’intention de les utiliser pendant une longue période de temps. La qualité de ces systèmes peut être dégradée avec le temps en raison des modifications complexes qui leur sont incorporées. Pour faire face à une telle dégradation lorsque elle dépasse un seuil critique, plusieurs stratégies peuvent être utilisées. Ces stratégies peuvent se résumer en: 1) remplaçant le système par un autre développé à partir de zéro, 2) poursuivant la maintenance(massive) du système malgré son coût ou 3) en faisant une réingénierie du système. Le remplacement et la maintenance massive ne sont pas des solutions adaptées lorsque le coût et le temps doivent être pris en compte, car elles nécessitent un effort considérable et du personnel pour assurer la mise en œuvre du système dans un délai raisonnable. Dans cette thèse, nous nous intéressons à la solution de réingénierie. En général, la réingénierie d’un système logiciel inclut toutes les activités après la livraison à l’utilisateur pour améliorer sa qualité. Cette dernière est souvent caractérisé par un ensemble d’attributs de qualité. Nous proposons trois contributions pour améliorer les attributs de qualité spécifiques, que soient:la maintenabilité, la compréhensibilité et la modularité. Afin d’améliorer la maintenabilité, nous proposons de migrer les systèmes logiciels orientés objets vers des systèmes orientés composants. Contrairement aux approches existantes qui considèrent un descripteur de composant comme un cluster des classes, chaque classe du système existant sera migré en un descripteur de composant. Afin d’améliorer la compréhensibilité, nous proposons une approche pour la reconstruction de modèles d’architecture d’exécution des systèmes orientés objet et de gérer la complexité des modèles résultants. Les modèles, graphes, générés avec notre approche ont les caractéristiques suivantes: les nœuds sont étiquetés avec des durées de vie et des probabilités d’existence permettant 1) une visualisation des modèles avec un niveau de détail. 2) de cacher/montrer la structure interne des nœuds. Afin d’améliorer la modularité des systèmes logiciels orientés objets, nous proposons une approche d’identification des modules et des services dans le code source de ces systèmes.Dans cette approche, nous croyons que la structure composite est la structure principale du système qui doit être conservée lors du processus de modularisation, le composant et ses composites doivent être dans le même module. Les travaux de modularisation existants qui ont cette même vision, supposent que les relations de composition entre les éléments du code source sont déjà disponibles ce qui n’est pas toujours évident. Dans notre approche, l’identification des modules commence par une étape de reconstruction de modèles d’architecture d’exécution du système étudié. Ces modèles sont exploités pour d’identification de relations de composition entre les éléments du code source du système étudié. Une fois ces relations ont été identifiées, un algorithme génétique conservatif aux relations de composition est appliqué sur le système pour identifier des modules. En dernier, les services fournis par les modules sont identifiés à l’aide des modèles de l’architecture d’exécution du système logiciel analysé. Quelques expérimentations et études de cas ont été réalisées pour montrer la faisabilité et le gain en maintenabilité, compréhensibilité et modularité des logiciels traités avec nos propositionsLegacy software systems often represent significant investmentsfor the companies that develop them with the intention of using themfor a long period of time. The quality of these systems can be degraded over time due to the complex changes incorporated to them.In order to deal with these systems when their quality degradation exceeds a critical threshold, a number of strategies can be used. Thesestrategies can be summarized in: 1) discarding the system and developinganother one from scratch, 2) carrying on the (massive) maintenance of the systemdespite its cost, or 3) reengineering the system. Replacement and massive maintenance are not suitable solutions when the cost and time are to be taken into account, since they require a considerable effort and staff to ensurethe system conclusion in a moderate time. In this thesis, we are interested in the reengineering solution. In general, software reengineering includes all activities following the delivery to the user to improve thesoftware system quality. This latter is often characterized with a set of quality attributes. We propose three contributions to improve specific quality attributes namely: maintainability, understandability and modularity.In order to improve maintainability, we propose to migrateobject oriented legacy software systems into equivalent component based ones.Contrary to exiting approaches that consider a component descriptor as a clusterof classes, each class in the legacy system will be migrated into a componentdescriptor. In order to improve understandability, we propose an approach forrecovering runtime architecture models of object oriented legacy systems and managing the complexity of the resulted models.The models recovered by our approach have the following distinguishing features: Nodes are labeled with lifespans and empirical probabilities of existencethat enable 1) a visualization with a level of detail. 2) the collapsing/expanding of objects to hide/show their internal structure.In order to improve modularity of object-oriented software systems,we propose an approach for identifying modulesand services in the source code.In this approach, we believe that the composite structure is the main structure of the system that must be retained during the modularization process, the component and its composites must be in the same module. Existing modularization works that has this same vision assumes that the composition relationships between the elements of the source code are already available, which is not always obvious. In our approach, module identification starts with a step of runtime architecture models recovery. These models are exploited for the identification of composition relationships between the elements of the source code. Once these relationships have been identified, a composition conservative genetic algorithm is applied on the system to identify modules. Lastly, the services provided by the modules are identified using the runtime architecture models of the software system. Some experimentations and casestudies have been performed to show the feasibility and the gain inmaintainability, understandability and modularity of the software systems studied with our proposals
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Segura, Danilo Costa Marim. "Integrando grades móveis em uma arquitetura orientada a serviços." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-13122016-095843/.
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O aumento no número de dispositivos móveis, como smartphones, tablets e laptops, e o avanço em seu potencial computacional permitiu considerá-los como recursos computacionais. O uso de recursos computacionais com maior proximidade vem crescendo ano após ano, sendo chamado de Fog computing, em que os elementos na borda da Internet são explorados, uma vez que os serviços computacionais convencionais podem estar indisponíveis ou sobrecarregados. Dessa forma, este projeto de Mestrado tem como foco possibilitar o uso de dispositivos móveis no provimento de serviços computacionais entre si de forma colaborativa através da heurística Maximum Regret adaptada, que busca alocar tarefas computacionais em dispositivos locais de forma a minimizar o consumo de energia e evitar dispositivos não confiáveis. Também há uma meta-heurística em um nível global, que interconecta os diferentes aglomerados de dispositivos móveis na borda da Internet, e possui informações globais de Quality of Service (QoS). Foram realizados experimentos que mostraram que evitar dispositivos móveis como recursos com um baixo grau de confiabilidade possibilitou diminuir o impacto no consumo de energia, além de ser possível diminuir os tempos de resposta e de comunicação ao ajustar a política de seleção de aglomerados externos.The increasing number of mobile devices, such as smartphones, tablets and laptops, as well as advances in their computing power have enabled us to consider them as resources, exploring the proximity. The use of near computing resources is growing year by year, being called as Fog computing, where the elements on the edge of the Internet are exploited, once the computer services providers could be unavailable or overloaded. Thus, this Masters project focuses on using mobile devices to provide computing services among them through a heuristic called Adapted Maximum Regret, which tries to minimize energy consumption and avoid untrustable devices. There is also top-level metaheuristic which interconnects different clusters of devices on the edge of the Internet with global information to guarantee Quality of Services (QoS). We conducted a set of experiments that showed us to avoid devices with a high degree of failures to save more energy when allocating tasks among them, as well as decreasing the applications response time and communication through adjusts in the selection algorithm of external agglomerates.
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Djang, Claire. "Two-Coloring Cycles In Complete Graphs." Oberlin College Honors Theses / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1370618319.
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Backman, Spencer Christopher Foster. "Combinatorial divisor theory for graphs." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51908.
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Chip-firing is a deceptively simple game played on the vertices of a graph, which was independently discovered in probability theory, poset theory, graph theory, and statistical physics. In recent years, chip-firing has been employed in the development of a theory of divisors on graphs analogous to the classical theory for Riemann surfaces. In particular, Baker and Norin were able to use this set up to prove a combinatorial Riemann-Roch formula, whose classical counterpart is one of the cornerstones of modern algebraic geometry. It is now understood that the relationship between divisor theory for graphs and algebraic curves goes beyond pure analogy, and the primary operation for making this connection precise is tropicalization, a certain type of degeneration which allows us to treat graphs as “combinatorial shadows” of curves. The development of this tropical relationship between graphs and algebraic curves has allowed for beautiful applications of chip-firing to both algebraic geometry and number theory. In this thesis we continue the combinatorial development of divisor theory for graphs. In Chapter 1 we give an overview of the history of chip-firing and its connections to algebraic geometry. In Chapter 2 we describe a reinterpretation of chip-firing in the language of partial graph orientations and apply this setup to give a new proof of the Riemann-Roch formula. We introduce and investigate transfinite chip-firing, and chip-firing with respect to open covers in Chapters 3 and 4 respectively. Chapter 5 represents joint work with Arash Asadi, where we investigate Riemann-Roch theory for directed graphs and arithmetical graphs, the latter of which are a special class of balanced vertex weighted graphs arising naturally in arithmetic geometry.
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Rosar, Kós Lassance Carlos Eduardo. "Graphs for deep learning representations." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2020. http://www.theses.fr/2020IMTA0204.
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Ces dernières années, les méthodes d'apprentissage profond ont atteint l'état de l'art dans une vaste gamme de tâches d'apprentissage automatique, y compris la classification d'images et la traduction automatique. Ces architectures sont assemblées pour résoudre des tâches d'apprentissage automatique de bout en bout. Afin d'atteindre des performances de haut niveau, ces architectures nécessitent souvent d'un très grand nombre de paramètres. Les conséquences indésirables sont multiples, et pour y remédier, il est souhaitable de pouvoir comprendre ce qui se passe à l'intérieur des architectures d'apprentissage profond. Il est difficile de le faire en raison de: i) la dimension élevée des représentations ; et ii) la stochasticité du processus de formation. Dans cette thèse, nous étudions ces architectures en introduisant un formalisme à base de graphes, s'appuyant notamment sur les récents progrès du traitement de signaux sur graphe (TSG). À savoir, nous utilisons des graphes pour représenter les espaces latents des réseaux neuronaux profonds. Nous montrons que ce formalisme des graphes nous permet de répondre à diverses questions, notamment: i) mesurer des capacités de généralisation ;ii) réduire la quantité de des choix arbitraires dans la conception du processus d'apprentissage ; iii)améliorer la robustesse aux petites perturbations ajoutées sur les entrées ; et iv) réduire la complexité des calculsIn recent years, Deep Learning methods have achieved state of the art performance in a vast range of machine learning tasks, including image classification and multilingual automatic text translation. These architectures are trained to solve machine learning tasks in an end-to-end fashion. In order to reach top-tier performance, these architectures often require a very large number of trainable parameters. There are multiple undesirable consequences, and in order to tackle these issues, it is desired to be able to open the black boxes of deep learning architectures. Problematically, doing so is difficult due to the high dimensionality of representations and the stochasticity of the training process. In this thesis, we investigate these architectures by introducing a graph formalism based on the recent advances in Graph Signal Processing (GSP). Namely, we use graphs to represent the latent spaces of deep neural networks. We showcase that this graph formalism allows us to answer various questions including: ensuring generalization abilities, reducing the amount of arbitrary choices in the design of the learning process, improving robustness to small perturbations added to the inputs, and reducing computational complexity
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Culp, Laura. "An Isomorphism Theorem for Graphs." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1952.
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In the 1970’s, L. Lovász proved that two graphs G and H are isomorphic if and only if for every graph X , the number of homomorphisms from X → G equals the number of homomorphisms from X → H . He used this result to deduce cancellation properties of the direct product of graphs. We develop a result analogous to Lovász’s theorem, but in the class of graphs without loops and with weak homomorphisms. We apply it prove a general cancellation property for the strong product of graphs.
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Van, Graan J. S. "Procurement of grapes for KWV from South African suppliers." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/6440.
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Van, Straten Celene Debra. "The construction of plant expression vectors for the introduction of leafroll disease resistance in grapevine." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51950.
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Thesis (MSc)--University of Stellenbosch, 2000.ENGLISH ABSTRACT: Grapevine leafroll is one of the most damaging viral diseases that affect many viticultural regions of the world. Numerous reports over the last few years have associated closterovirus-like particles with leafroll disease. To date, eight serologically distinct closteroviruses have been isolated from leafroll infected vines, of which grapevine leafroll associated closterovirus-3 (GLRaV-3) is the best characterized. Virus resistance in transgenic plants based on the expression of a virusderived gene is known as pathogen-derived resistance. The viral coat protein (CP) gene, which expresses a structural protein responsible for coating the virus particles, was used in the first demonstration of virus-derived resistance. Coat protein-mediated resistance is currently the most feasible and most widely used method to obtain virus resistance in crop plants. The CP gene of a South African isolate of GLRaV-3 infected grapevine was isolated, cloned and sequenced. Double stranded RNA (dsRNA) was extracted from GLRaV-3 infected material and a high molecular weight band, of -18 kb was identified from infected vines. The dsRNA was used as a template in a reverse transcription PCR together with GLRaV-3 CP gene specific primers for the amplification of the GLRaV-3 CP gene (975 bp). The GLRaV-3 CP gene was cloned into the pGem®-T Easy vector. Clones hosting the CP gene in the sense (pLR3CP+) and antisense (pLR3CP-) orientations respectively were obtained. The sequence obtained from these two clones showed 99.26 % similarity to the only other GLRaV-3 CP nucleotide sequence available. The GLRaV-3 CP gene was excised from pLR3CP+ and pLR3CP- and subcloned into a plant expression vector, pCAMBIA 3301 in the sense (pCamBLR3CP+) and antisense (pCamBLR3CP-) orientations respectively, therefore enabling sense and antisense gene expression in transgenic plants. The GLRaV-3 CP gene was also subcloned from pCamBLR3CP+ into another plant expression vector, pCAMBIA 2301 in the sense orientation and designated as pCVSLR3CP+. These three constructs were given to Dr. M. Vivier (Institute for Wine Biotechnology, Stellenbosch) for grapevine transformation experiments. Two of these constructs, pCamBLR3CP+ and pCamBLR3CP- as well as pCAMBIA 3301 were used to transform Nicotiana tabacum by Agrobacterium tumefaciens-mediated transformation. Plants were selected for their ability to withstand the herbicide, Basta. This resistance is due to the presence of a plant selectable marker gene on each of these constructs, known as the bar gene. PCR with GLRaV-3 CP gene specific primers showed no amplification of the GLRaV-3 CP gene in the plants transformed with pCamBLR3CP+ and pCamBLR3CP-. Southern blot analysis with the GLRaV-3 CP gene as hybridization probe showed no signal for these plants, thus confirming the PCR results. PCR with bar gene specific primers showed no amplification of the bar gene in the plants infected with pCAMBIA 3301. The plants transformed with pCamBLR3CP+ and pCamBLR3CP- were also screened for the presence of the bar gene. Three of the eight plants tested showed amplification of the -560 bp bar gene. This result suggests that these plants were transformed with pCAMBIA 3301 (vector without the ligated GLRaV-3 CP gene) and not pCamBLR3CP+ or pCamBLR3CP- as had been expected. This project provides preliminary work for the subsequent transformation of grapevine with the GLRaV-3 CP gene, in an attempt to impart virus resistance.
AFRIKAANSE OPSOMMING: Wingerd rolblaar is een van die mees beskadigende virale siektes wat baie wingerd areas in die wêreld aantas. In Aantal verslae oor die afgelope jare het closterovirus partikels met wingerd rolblaar geassosieer. Tot hede, is agt serologiese onderskeibare closterovirusse geïsoleer vanuit geaffekteerde wingerde, waarvan wingerd rolblaar geassosieerde closterovirus-3 (GLRaV-3) die beste gekarakteriseerd is. Virus bestandheid in transgeniese plante gebaseer op die uitdrukking van gene afkomstig vanaf virusse, staan bekend as patogeen-afgeleide weerstand. Die virale kapsule protein (CP) geen vervaardig In strukturele protein wat verantwoordelik is vir die bedekking van die virus partikel. Dié geen was gebruik in die eerste demonstrasie van patogeen-afgeleide weerstand. Kapsuul protein-bemiddelde weerstand is tans die mees praktiese en algemene gebruikte metode om virus weerstand in plant gewasse te verkry. Die CP geen van In Suid Afrikaanse isolaat van GLRaV-3 geïnfekteerde wingerde is geïsoleer, gekloneer en die volgorde is bepaal. Dubbelstring RNA (dsRNA) was uit GLRaV-3 geïnfekteerde materiaal geëkstraheer en In hoë molekulêre gewig band van -18 kb is geïdentifiseer. Die dsRNA is gebruik as In templaat vir In omgekeerde transkripsie PKR saam met GLRaV-3 CP geen spesifieke inleiers vir die amplifikasie van die GLRaV-3 CP geen (975 bp). Die GLRaV-3 CP geen is gekloneer in die pGem®-T Easy vektor. Klone met die CP geen in die sin (pLR3CP+) en teensin (pLR3CP-) oriëntasies respektiewelik is verkry. Die volgorde wat verkry is vanuit hierdie twee klone dui op In 99.26 % ooreenstemming met die enigste ander GLRaV-3 CP geen volgorde wat beskikbaar is. Die GLRaV-3 CP geen is uit pLR3CP+ en pLR3CP- gesny en is gesubkloneer in In plant ekspressie vektor, pCAMBIA 3301 in die sin (pCamBLR3CP+) en teensin (pCamBLR3CP-) oriëntasies respektiewelik, wat die sin en teensin geen ekspressie in transgeniese plante in staat stel. Die GLRaV-3 CP geen was ook gesubkloneer vanaf pCamBLR3CP+ in In ander plant ekspressie vektor, pCAMBIA 2301 in die sin orientasie en is as pCVSLR3CP+ benoem. Hierdie drie konstruksies is aan Dr. M. Vivier (Instituut vir Wyn Biotegnologie, Stellenbosch) gegee vir wingerd transformasie eksperimente. Twee van hierdie konstruksies, pCamBLR3CP+ en pCamBLR3CP- asook pCAMBIA 3301 is gebruik om Nicotiana tabacum deur middel van Agrobacterium tumefaciens-bemiddelde transformasie te transformeer. Plante is geselekteer vir hul vermoë om die onkruiddoder, Basta, te weerstaan. Die teenwoordigheid van die plant selekteerbare merker geen, bar, op elke konstruksie lui tot dié weerstand. Die plante wat getransformeer is met pCamBLR3CP+ en pCamBLR3CP- is deur PKR saam met die GLRaV-3 CP geen spesifieke inleiers getoets, en geen amplifikasie van die GLRaV-3 CP geen is getoon nie. Southern blot analise met die GLRaV-3 CP geen as hibridisasie peiler het geen sein gewys vir hierdie plante nie, wat die PKR resultate bevestig. Die plante wat getransformeer is met pCAMBIA 3301 is deur PKR saam met die bar geen spesifieke inleiers getoets, en geen amplifikasie van die bar geen is getoon nie. Die plante wat getransformeer is met pCamBLR3CP+ en pCamBLR3CP- is ook getoets vir die teenwoordigheid vir die bar geen. Drie van die agt plante wat getoets is, het amplifikasie van die -560 bp bar geen getoon. Hierdie onverwagte resultate stel voor dat dié plante met pCAMBIA 3301 (vektor sonder die geligeerde GLRaV-3 CP geen) en nie met pCamBLR3CP+ en pCamBLR3CPgetransformeer is nie. Hierdie projek verskaf voorlopige werk vir die daaropvolgende transformasie van wingerd met die GLRaV-3 CP geen in 'n poging om virus bestandheid te verskaf.
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Adamus, Lech. "Sufficient conditions for existence of long cycles in graphs." Paris 11, 2008. http://www.theses.fr/2008PA112203.
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Le but de cette thèse est de présenter des conditions suffisantes pour l'existence de longs cycles dans les graphes simples et les graphes orientés, c'est à dire des cycles passant par plus de la moitié des sommets d'un graphe donné. Plus précisément, nous voulons trouver la taille minimale d'un graphe donné G garantissant qu'un cycle de longueur prescrite est contenu dans G. On pourra considérer une modification de cette condition en ajoutant une borne sur le degré minimum de G. Nous étudions ce problème pour les graphes simples, en particulier les graphes bipartis et aussi les graphes orientés dans lesquels on considère toutes les orientations possibles d'un cycle de longueur donnéeThe aim of this thesis is to present sufficient conditions for existence of long cycles in simple graphs and in directed graphs, that is, cycles which pass through more than half of the vertices in a given graph. Namely, we want to find the minimal size of a given graph G guaranteeing that a cycle of prescribed length is contained in G. Optionally we consider a modification of this condition by adding a bound on the minimal degree of G. We investigate this problem for simple graphs, particularly bipartite, and also for digraphs, where all possible orientations of a cycle of given length are considered
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Song, Zixia. "Extremal Functions for Contractions of Graphs." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6425.
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In this dissertation, a problem related to Hadwiger's conjecture has been studied. We first proved a conjecture of Jakobsen from 1983 which states that every simple graphs on $n$ vertices and at least (11n-35)/2 edges either has a minor isomorphic to K_8 with one edge deleted or is isomorphic to a graph obtained from disjoint copies of K_{1, 2, 2, 2, 2} and/or K_7 by identifying cliques of size five. We then studied the extremal functions for complete minors. We proved that every simple graph on nge9 vertices and at least 7n-27 edges either has a minor, or is isomorphic to K_{2, 2, 2, 3, 3}, or is isomorphic to a graph obtained from disjoint copies of K_{1, 2, 2, 2, 2, 2} by identifying cliques of size six. This result extends Mader's theorem on the extremal function for K_p minors, where ple7. We discussed the possibilities of extending our methods to K_{10} and K_{11} minors. We have also found the extremal function for K_7 plus a vertex minor.
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Chow, Kent. "GPLOT : a language for plotting graphs." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66062.
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Lee, Bongshin. "Interactive visualizations for trees and graphs." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3519.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Computer Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Robertshaw, Andrew Martin. "Neighbourhood conditions for factors in graphs." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431324.
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Hart, Michael. "Degree bounds for graphs in surfaces." Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335630.
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Kelner, Judith. "Using directed graphs for software visualisation." Thesis, University of Kent, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334043.
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Beis, Michail. "Greedy algorithms for random regular graphs." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427021.
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Lavinus, Joseph W. "Heuristics for laying out information graphs." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12302008-063333/.
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Betrabet, Sangita. "A query language for information graphs." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-10312009-020301/.
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Zanetti, Luca. "Algorithms for partitioning well-clustered graphs." Thesis, University of Bristol, 2018. http://hdl.handle.net/1983/e6ba8929-6488-4277-b91b-4f4f7eda2b26.
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Graphs occurring in the real world usually exhibit a high level of order and organisation: higher concentration of edges within the same group of vertices, and lower concentration among different groups. A common way to analyse these graphs is to partition the vertex set of a graph into clusters according to some connectivity measure. Graph clustering has been widely applied to many fields of computer science, from machine learning to bioinformatics and social network analysis. The focus of this thesis is to design and analyse algorithms for partitioning graphs presenting a strong cluster-structure, which we call well-clustered. We first study the spectral properties of the Laplacian matrix of such graphs, and prove a structure theorem that relates the eigenvectors corresponding to the smallest eigenvalues of the Laplacian matrix of a graph to the structure of its clusters. We then harness this theorem to analyse Spectral Clustering, arguably the most popular graph clustering algorithm. We give for the first time approximation guarantees on the number of misclassified vertices by Spectral Clustering when applied to well-clustered graphs. Since Spectral Clustering needs to compute as many eigenvectors of the Laplacian matrix as the number of clusters in the graph, its performance deteriorates as this number grows. We present an algorithm that overcomes this issue without compromising its accuracy. This algorithm runs in time nearly linear in the number of the edges and independently of the number of clusters in the input graph. Finally, we tackle the problem of partitioning a graph whose description is distributed among many sites. We present a distributed algorithm that works in a few synchronous rounds, requires limited communication complexity, and achieves the same guarantees of Spectral Clustering as long as the clusters are balanced in size.
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Cooley, Oliver Josef Nikolaus. "Embedding Problems for Graphs and Hypergraphs." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/766/.
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This thesis deals with the problem of finding some substructure within a large graph or hypergraph. In the case of graphs, we consider the substructures consisting of fixed subgraphs or families of subgraphs, perfect graph packings and spanning subgraphs. In the case of hypergraphs we consider the substructure consisting of a hypergraph whose order is linear in the order of the large hypergraph. I will show how these problems are extensions of more basic and well-known results in graph theory. I will give full proofs of three new embedding results, two for graphs and one for hypergraphs. I will also discuss the regularity lemma for graphs and hypergraphs, an important tool which underpins these and many similar embedding results. Finally, I will also discuss graph and hypergraph Ramsey numbers, since two of the embedding results have important applications to Ramsey numbers which improve upon previously known results.
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Granholm, Jonas. "Local Conditions for Cycles in Graphs." Licentiate thesis, Linköpings universitet, Matematik och tillämpad matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-156118.
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A Hamilton cycle in a graph is a cycle that passes through every vertex of the graph. A graph is called Hamiltonian if it contains such a cycle. The problem of determining if a graph is Hamiltonian has been studied extensively, and there are many known sufficient conditions for Hamiltonicity. A large portion of these conditions relate the degrees of vertices of the graph to the number of vertices in the entire graph, and thus they can only apply to a limited set of graphs with high edge density. In a series of papers, Asratian and Khachatryan developed local analogues of some of these criteria. These results do not suffer from the same drawbacks as their global counterparts, and apply to wider classes of graphs. In this thesis we study this approach of creating local conditions for Hamiltonicity, and use it to develop local analogues of some classic results. We also study how local criteria can influence other global properties of graphs. Finally, we will see how these local conditions can allow us to extend theorems on Hamiltonicity to infinite graphs.
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Rezanejad, Morteza. "Flux graphs for 2D shape analysis." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117144.
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This thesis considers a method for computing skeletal representations based on the average outward flux (AOF) of the gradient of the Euclidean distance function to the boundary of a 2D object through the boundary of a region that is shrunk. It then shows how the original method, developed by Dimitrov et al. [17] can be optimized and made more efficient and proposes an algorithm for computing flux invariants which is a number of times faster. It further exploits a relationship between the AOF and the object angle at endpoints, branch points and regular points of the skeleton to obtain more complete boundary reconstruction results than those demonstrated in prior work. Using this optimized implementation, new measures for skeletal simplification are proposed based on two criteria: the uniqueness of an inscribed disk as a tool for defining salience, and the limiting average outward flux value. The simplified skeleton when abstracted as a directed graph is shown to be far less complex than popular skeletal graphs in the literature, such as the shock graph, by a number of graph complexity measures including: number of nodes, number of edges, depth of the graph, number of skeletal points, and the sum of topological signature vector (TSV) values. We conclude the thesis by applying the simplified graph to a view-based object recognition experiment previously arranged for shock graphs. The results suggest that our new simplified graph yields recognition scores very close to those obtained using shock graphs but with a smaller number of nodes, edges, and skeletal points.Ce mémoire propose une méthode pour calculer des représentations squelettiques en fonction du flux moyen décrit par le gradient de la fonction de distance Euclidienne aux limites d'un objet 2D qui rétrécit. La méthode originale développée par Dimitrov et al. [17] est ensuite optimisée afin de calculer des invariants de flux plus rapidement. Une relation entre l'AOF et l'angle de l'objet aux extrémités (aux points de branches et des points réguliers du squelette) est exploitée afin d'obtenir une reconstruction plus précises des limites de l'objet par rapport aux travaux précédents. En utilisant cette implémentation optimisée, de nouvelles mesures de simplification de squelettes sont proposées selon deux critères: l'unicité d'un disque inscrit comme un outil permettant de définir la saillance, et la limitation de la moyenne du flux à l'extérieur. Il est démontré que le squelette simplifié, abstrait par un graphe orienté, est beaucoup moins complexe que des graphes squelettiques conventionnels mentionnés dans la littérature, tel que le graphe de choc. Les mesures de complexité de graphe comprennent le nombre de nuds, le nombre de bords, la profondeur du graphe, le nombre de points du squelette et la somme des valeurs du vecteur des signes topologiques (TSV). La thèse se finit en appliquant le graphe simplifié au problème de reconnaissance d'objets basée sur la vue, préalablement adapté pour l'utilisation de graphes de choc. Les résultats suggèrent que notre nouveau graphe simplifié atteint des performances similaires à celles des graphes de choc, mais avec moins de nuds, de bords et de points du squelette plus rapide.
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Sarkar, Amites. "Extremal problems for graphs and hypergraphs." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625020.
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Rommedahl, David, and Martin Lindström. "Learning Sparse Graphs for Data Prediction." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295623.
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Graph structures can often be used to describecomplex data sets. In many applications, the graph structureis not known but must be inferred from data. Furthermore, realworld data is often naturally described by sparse graphs. Inthis project, we have aimed at recreating the results describedin previous work, namely to learn a graph that can be usedfor prediction using an ℓ1-penalised LASSO approach. We alsopropose different methods for learning and evaluating the graph. We have evaluated the methods on synthetic data and real-worldSwedish temperature data. The results show that we are unableto recreate the results of the previous research team, but wemanage to learn sparse graphs that could be used for prediction. Further work is needed to verify our results.Grafstrukturer kan ofta användas för att beskriva komplex data. I många tillämpningar är grafstrukturen inte känd, utan måste läras från data. Vidare beskrivs verklig data ofta naturligt av glesa grafer. I detta projekt har vi försökt återskapa resultaten från ett tidigare forskningsarbete, nämligen att lära en graf som kan användas för prediktion med en ℓ1pennaliserad LASSO-metod. Vi föreslår även andra metoder för inlärning och utvärdering av grafen. Vi har testat metoderna på syntetisk data och verklig temperaturdata från Sverige. Resultaten visar att vi inte kan återskapa de tidigare forskarnas resultat, men vi lyckas lära in glesa grafer som kan användas för prediktion. Ytterligare arbete krävs för att verifiera våra resultat.
Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
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Wang, Guan. "STREAMING HYPERGRAPH PARTITION FOR MASSIVE GRAPHS." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1385097649.
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Szabó, Tibor. "Extremal problems for graphs and hypergraphs /." The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487935125880928.
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Cashy, John Peter. "Irreducible graphs for the Klein bottle /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488195154358306.
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Ruan, Da. "Statistical methods for comparing labelled graphs." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24963.
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Due to the availability of the vast amount of graph-structured data generated in various experiment settings (e.g., biological processes, social connections), the need to rapidly identify network structural differences is becoming increasingly prevalent. In many fields, such as bioinformatics, social network analysis and neuroscience, graphs estimated from the same experimental settings are always defined on a fixed set of objects. We formalize such a problem as a labelled graph comparison problem. The main issue in this area, i.e. measuring the distance between graphs, has been extensively studied over the past few decades. Although a large distance value constitutes evidence of difference between graphs, we are more interested in the issue of inferentially justifying whether a distance value as large or larger than the observed distance could have been obtained simply by chance. However, little work has been done to provide the procedures of statistical inference necessary to formally answer this question. Permutation-based inference has been proposed as a theoretically sound approach and a natural way of tackling such a problem. However, the common permutation procedure is computationally expensive, especially for large graphs. This thesis contributes to the labelled graph comparison problem by addressing three different topics. Firstly, we analyse two labelled graphs by inferentially justifying their independence. A permutation-based testing procedure based on Generalized Hamming Distance (GHD) is proposed. We show rigorously that the permutation distribution is approximately normal for a large network, under three graph models with two different types of edge weights. The statistical significance can be evaluated without the need to resort to computationally expensive permutation procedures. Numerical results suggest the validity of this approximation. With the Topological Overlap edge weight, we suggest that the GHD test is a more powerful test to identify network differences. Secondly, we tackle the problem of comparing two large complex networks in which only localized topological differences are assumed. By applying the normal approximation for the GHD test, we propose an algorithm that can effectively detect localised changes in the network structure from two large complex networks. This algorithm is quickly and easily implemented. Simulations and applications suggest that it is a useful tool to detect subtle differences in complex network structures. Finally, we address the problem of comparing multiple graphs. For this topic, we analyse two different problems that can be interpreted as corresponding to two distinct null hypotheses: (i) a set of graphs are mutually independent; (ii) graphs in one set are independent of graphs in another set. Applications for the multiple graphs problem are commonly found in social network analysis (i) or neuroscience (ii). However, little work has been done to inferentially address the problem of comparing multiple networks. We propose two different statistical testing procedures for (i) and (ii), by again using a normality approximation for GHD. We extend the normality of GHD for the two graphs case to multiple cases, for hypotheses (i) and (ii), with two different permutation strategies. We further build a link between the test of group independence to an existing method, namely the Multivariate Exponential Random Graph Permutation model (MERGP). We show that by applying asymptotic normality, the maximum likelihood estimate of MERGP can be analytically derived. Therefore, the original, computationally expensive, inferential procedure of MERGP can be abandoned.
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Rollin, Jonathan [Verfasser], and M. [Akademischer Betreuer] Axenovich. "Extremal and Ramsey Type Questions for Graphs and Ordered Graphs / Jonathan Rollin ; Betreuer: M. Axenovich." Karlsruhe : KIT-Bibliothek, 2017. http://d-nb.info/1137946563/34.
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Erasmus, George-Chatwind. "Developing an international export marketing strategy for South African table grapes." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53358.
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Thesis (MBA)--Stellenbosch University, 2003.ENGLISH ABSTRACT: After the deregulation of the South African deciduous fruit industry in 1997 an unregulated grape marketing environment replaced the single channel marketing system. Many new South African grape exporters were now involved in an uncoordinated and uncooperative marketing environment. Each marketing organisation implemented their own marketing plans resulting in an increase in competition among South African suppliers. The South African grape supplies originate from various production areas, each with their unique characteristics and qualities, making it a very competitive environment. South African grapes also share the various markets with other competing Southern Hemisphere grape suppliers. This level of competition makes it very important for the South African grape industry to have a uniform marketing strategy. To achieve a uniform industry marketing strategy the industry has to develop a common vision - to be the preferred table grape supplier in our target markets - that forms the basis of developing a generic South African table grape marketing strategy. A single vision gives the competitive export companies a common marketing objective. This study includes recommendations to industry stakeholders that will enable them to formulate their own marketing strategy, all within the guidelines of the common vision that is adjusted to the specific needs of their respective target markets.
AFRIKAANSE OPSOMMING: Na die deregulering van die Suid-Afrikaanse sagtevrugtebedryf in 1997 het 'n ongereguleerde bemarkingsomgewing die enkelkanaalbemarking vervang. Verskeie nuwe Suid-Afrikaanse tafeldruifuitvoerders was nou betrokke by 'n ongekoërdineerde bemarkingsomgewing waar daar geen samewerking tussen uitvoerders was nie. Elke bemarkingsagent het sy eie bemarkingsplan gevolg wat gelei het tot 'n toename in kompetisie tussen Suid-Afrikaanse produsente. Die Suid-Afrikaanse tafeldruiwe word in verskillende produksieareas geoes, elk met hul unieke eienskappe en kwaliteite. Dit maak dit 'n baie kompeterende omgewing. Die Suid-Afrikaanse druiwe kompeteer ook in die mark met ander Suidelike Halfrond druiwe produsente. Met so 'n hoë vlak van kompetisie, is dit belangrik dat die Suid- Afrikaanse industrie 'n eenvormige bemarkingstrategie het. Om 'n eenvormige bemarkingstrategie vir die industrie te formuleer, moet die industrie visie - om die voorkeurverskaffer van tafeldruiwe in ons teikenmarkte te wees - die basis vorm vir die formulering van 'n generiese bemarkingstrategie vir Suid-Afrikaanse tafeldruiwe. 'n Eenvormige visie bied vir die kompeterende bemarkingsagente 'n gemene doelwit. Hierdie werkstuk sluit aanbevelings in wat vir rolspelers leiding sal gee om hul eie bemarkingstrategie te formuleer wat die doelwitte van 'n eenvormige visie onderskryf, maar nog steeds die behoeftes van die onderskeie teikenmarkte aanspreek.
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Mohr, Margaret Joan. "An assessment of middle grades preservice teachers' mathematics knowledge for teaching." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1776.
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Björklund, Henrik. "Combinatorial Optimization for Infinite Games on Graphs." Doctoral thesis, Uppsala University, Department of Information Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4751.
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Games on graphs have become an indispensable tool in modern computer science. They provide powerful and expressive models for numerous phenomena and are extensively used in computer- aided verification, automata theory, logic, complexity theory, computational biology, etc.
The infinite games on finite graphs we study in this thesis have their primary applications in verification, but are also of fundamental importance from the complexity-theoretic point of view. They include parity, mean payoff, and simple stochastic games.
We focus on solving graph games by using iterative strategy improvement and methods from linear programming and combinatorial optimization. To this end we consider old strategy evaluation functions, construct new ones, and show how all of them, due to their structural similarities, fit into a unifying combinatorial framework. This allows us to employ randomized optimization methods from combinatorial linear programming to solve the games in expected subexponential time.
We introduce and study the concept of a controlled optimization problem, capturing the essential features of many graph games, and provide sufficent conditions for solvability of such problems in expected subexponential time.
The discrete strategy evaluation function for mean payoff games we derive from the new controlled longest-shortest path problem, leads to improvement algorithms that are considerably more efficient than the previously known ones, and also improves the efficiency of algorithms for parity games.
We also define the controlled linear programming problem, and show how the games are translated into this setting. Subclasses of the problem, more general than the games considered, are shown to belong to NP intersection coNP, or even to be solvable by subexponential algorithms.
Finally, we take the first steps in investigating the fixed-parameter complexity of parity, Rabin, Streett, and Muller games.
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Huynh, Tony. "The Linkage Problem for Group-labelled Graphs." Thesis, University of Waterloo, University of Waterloo, 2009. http://hdl.handle.net/10012/4716.
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This thesis aims to extend some of the results of the Graph Minors Project of Robertson and Seymour to "group-labelled graphs". Let $\Gamma$ be a group. A $\Gamma$-labelled graph is an oriented graph with its edges labelled from $\Gamma$, and is thus a generalization of a signed graph.
Our primary result is a generalization of the main result from Graph Minors XIII. For any finite abelian group $\Gamma$, and any fixed $\Gamma$-labelled graph $H$, we present a polynomial-time algorithm that determines if an input $\Gamma$-labelled graph $G$ has an $H$-minor. The correctness of our algorithm relies on much of the machinery developed throughout the graph minors papers. We therefore hope it can serve as a reasonable introduction to the subject.
Remarkably, Robertson and Seymour also prove that for any sequence $G_1, G_2, \dots$ of graphs, there exist indices $i
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Elling, Volker Wilhelm. "A spectral method for mapping dataflow graphs." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8161.
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Sbihi, Amine M. (Amine Mohammed). "Covering times for random walks on graphs." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74538.
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This thesis is a contribution to the covering times problems for random walks on graphs. By considering uniform random walks on finite connected graphs, the covering time is defined as the time (number of steps) taken by the random walk to visit every vertex. The motivating problem of this thesis is to find bounds for the expected covering times. We provide explicit bounds that are uniformly valid over all starting points and over large classes of graphs. In some cases the asymptotic distribution of the suitably normalized covering time is given as well.
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Au, Yeung Chun-kan. "Solutions for some problems in star graphs /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B30708394.
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Wumaier, Aierken. "Degree bounds for the circumference of graphs." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967233402.
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Aguirre, Guerrero Daniela. "Word-processing-based routing for Cayley graphs." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/667410.
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This Thesis focuses on the problem of generic routing in Cayley Graphs(CGs). These graphs are a geometric representation of algebraic groups and have been used as topologies of a wide variety of communication networks.
The problem is analyzed from the Automatic Group Theory (AGT), which states that the structure of CGs can be encoded in a set of automatons. From these approach, word-processing techniques are used to design a generic routing scheme that has low complexity; guarantees packet delivery; and provides minimal routing, path diversity and fault-tolerance. These scheme is supported on a set low complexity algorithms for path computation in CGs.
The contributions of this Thesis also include an analysis of the topological properties of CGs and their impact on the performance and robustness of networks that use them as topologyEsta Tesis aborda el problema del encaminamiento genérico en grafos Cayley (CGs, por sus siglas en inglés). Estos grafos son una representación geométrica de grupos algebraicos y han sido utilizados como topologías de una gran variedad de redes de comunicación. El problema es analizado desde la perspectiva de la Teoría de Grupos Automáticos (AGT, por sus siglas en inglés), la cual establece que la estructura de los CGs puede ser codificada en un conjunto de autómatas. Siguiendo este enfoque, se aplicaron técnicas de procesamiento de texto para diseñar un esquema de encaminamiento genérico de baja complejidad; el cual garantiza la entrega de paquetes; y provee encaminamiento mínimo, diversidad de caminos y tolerancia a fallas. Este esquema es soportado en un conjunto de algoritmos de baja complejidad para el computo de caminos en CGs. Las contribuciones de esta Tesis también incluyen un análisis de las propiedades topológicas de los CGs y su impacto en el desempeño y robustez de las redes que los utilizan como topología
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Haraldsson, Erik. "Combining unobtainable shortest path graphs for OSPF." Thesis, Linköping University, Department of Mathematics, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12401.
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The well-known Dijkstra's algorithm uses weights to determine the shortest path. The focus here is instead on the opposite problem, does there exist weights for a certain set of shortest paths? OSPF (Open Shortest Path First) is one of several possible protocols that determines how routers will send data in a network like the internet. Network operators would however like to have some control of how the traffic is routed, and being able to determine the weights, which would lead to the desired shortest paths to be used, would be a help in this task.The first part of this thesis is a mathematical explanation of the problem with a lot of examples to make it easier to understand. The focus here is on trying to combine several routing patterns into one, so that the result will be fewer, but more fully spanned, routing patterns, and it can e.g. be shown that there can't exist a common set of weights if two routing patterns can't be combined.The second part is a program that can be used to make several tests and changes to a set of routing patterns. It has a polynomial implementation of a function that can combine routing patterns. The examples that I used to combine routing patterns, showed that this will increase the likelihood of finding and significantly speed up the computation of a “valid cycle”.
Egentligen 30p/45hp, men det fanns inte som alternativ.
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Ibarra, Louis Walter. "Dynamic algorithms for chordal and interval graphs." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58573.pdf.
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