1,720,995 research outputs found
Spanning structures in random graphs and hypergraphs
No full textEmbedding spanning structures into the random graph G(n,p) is a well-studied problem in random graph theory, but when one turns to the random r-uniform hypergraph H(r)(n,p) much less is known. In this thesis we will examine this topic from different perspectives, providing insights into various aspects of the theory of random graphs. Our results cover the determination of existence thresholds in two models, as well as an algorithmic approach. For the embeddings, we work with random and pseudorandom structures.
Together with Person we first notice that a general result of Riordan can be adapted from random graphs to hypergraphs and provide sufficient conditions for when H(r)(n,p) contains a given spanning structure asymptotically almost surely. As applications, we discuss several spanning structures such as cubes, lattices, spheres, and Hamilton cycles in hypergraphs.
Moreover, we study universality, i.e. when does an r-uniform hypergraph contain every hypergraph on n vertices with maximum vertex degree bounded by [delta]? For H(r)(n,p), it is shown with Person that this holds for p = w(ln n/n)1/[delta]) asymptotically almost surely by combining approaches taken by Dellamonica, Kohayakawa, Rödl, and Ruciński, of Ferber, Nenadov, and Peter, and of Kim and Lee.
Any hypergraph that is universal for the family of bounded degree r-uniform hypergraphs has to contain [omega](nr-r/[delta]) edges. With Hetterich and Person we exploit constructions of Alon and Capalbo to obtain universal r-uniform hypergraphs with the optimal number of edges O(nr-r/[delta]) when r is even, r | [delta], or [delta] = 2. Furthermore, we generalise the result of Alon and Asodi about optimal universal graphs for the family of graphs with at most m edges and no isolated vertices to hypergraphs.
In an r-uniform hypergraph on n vertices a tight Hamilton cycle consists of n edges such that there exists a cyclic ordering of the vertices where the edges correspond to consecutive segments of r vertices. In collaboration with Allen, Koch, and Person we provide a first deterministic polynomial time algorithm, which finds asymptotically almost surely tight Hamilton cycles in random r-uniform hypergraphs with edge probability at least C log3 n/n. This result partially answers a question of Nenadov and Skorić and of Dudek and Frieze who proved that tight Hamilton cycles exist already for p = w(1/n) for r = 3 and p [größer/gleich] (e + o(1))/n for r [größer/gleich] 4 using a second moment argument. Moreover our algorithm is superior to previous results of Allen, Böttcher, Kohayakawa, and Person and Nenadov and Skorić.
Lastly, we study the model of randomly perturbed dense graphs introduced by Bohman, Frieze and Martin, that is, the union of any n-vertex graph G[alpha] with minimum degree at least [alpha]n and G(n,p). For any fixed [alpha] > 0, and p = w(n-2/([delta]+1)), we show with Böttcher, Montgomery, and Person that G[alpha] UG(n,p) almost surely contains any single spanning graph with maximum degree [delta], where [delta] [größer/gleich] 5. As in previous results concerning this model, the bound used for p is lower by a log-term in comparison to the conjectured threshold for the general appearance of such subgraphs in G(n,p) alone. The new techniques we introduce also give simpler proofs of related results in the literature on trees and factors.Das Finden von aufspannenden Strukturen im zufälligen Graphen G(n,p) is ein viel studiertes Problem in der Theorie der zufälligen Graphen, aber sobald man sich dem zufälligen r-uniformen Hypergraphen H(r)(n,p) zuwendet ist noch deutlich weniger bekannt. In dieser Arbeit beschäftigen wir uns mit diesem Thema aus verschiedenen Blickwinkeln und geben dabei einen Einblick in viele Aspekte des Studiums von zufälligen Graphen. Zu unseren Ergebnissen gehören sowohl die Bestimmung von Schwellenwerten in verschiedenen Modellen als auch ein algorithmischer Zugang. Für die Einbettungen arbeiten wir mit zufälligen und pseudozufälligen Strukturen.
Zusammen mit Person stellen wir zuerst fest, dass sich ein allgemeines Ergebnis von Riordan von zufälligen Graphen auf Hypergraphen verallgemeinern lässt, und zeigen eine hinreichende Bedingung dafür, dass H(r)(n,p) eine gegebene aufspannende Struktur asymptotisch fast sicher enthält. Als Anwendung diskutieren wir verschiedene Strukturen, wie Würfel, Gitter und Hamiltonkreise in Hypergraphen. Desweiteren studieren wir Universalität, also die Frage, wann ein r-uniformer Hypergraph "alle" Hypergraphen auf n Knoten mit maximalem Knotengrad höchstens [delta] enthält. Für H(r)(n,p) zeigen wir mit Person, dass dies für p = w(ln n/n)1/[delta]) asymptotisch fast sicher stimmt, indem wir Ideen von Dellamonica, Kohayakawa, Rödl und Ruciński, von Ferber, Nenadov und Peter und von Kim und Lee kombinieren.
Jeder Hypergraph, der universal für die Familie der gradbeschränkten Hypergraphen ist, muss mindestens [omega](nr-r/[delta]) Kanten besitzen. Mit Hetterich und Person nutzen wir Konstruktionen von Alon und Capalbo aus, um daraus universale r-uniforme Hypergraphen mit optimaler Kantenanzahl O(nr-r/[delta]) zu konstruieren, falls r gerade ist, r | [delta], or [delta] = 2. Darüberhinaus verallgemeinern wir ein Resultat von Alon und Asodi über optimale universale Graphen für die Familie der Graphen mit m Kanten und ohne isolierte Knoten auf Hypergraphen.
In einem r-uniformen Hypergraphen auf n Knoten besteht ein enger Hamiltonkreis aus n Kanten, so dass es eine zyklsiche Anordnung der Knoten gibt, in der die Kanten zu aufeinanderfolgenden Segmenten gehören. In Kollaboration mit Allen, Koch und Person finden wir einen ersten deterministischen Polynomialzeitalgorithmus, der asymptotisch fast sicher einen engen Hamiltonkreis in H(r)(n,p) findet für p [größer/gleich] C log3 n/n. Damit beantworten wir teilweise eine Frage von Nenadov und Skorić und von Dudek und Frieze, die zeigten, dass enge Hamiltonkreise bereits für p [größer/gleich] (e + o(1))/n exisiteren für r [größer/gleich] 4 (p = w(1/n) for r = 3), indem sie die Methode des zweiten Moments anwendeten. Desweiteren verbessern wir zuvorige Algorithmen von Allen, Böttcher, Kohayakawa und Person und Nenadov und Skorić.
Zuletzt widmen wir uns dem Modell der zufällig manipulierten dichten Graphen, dass von Bohman, Frieze und Martin eingeführt wurde. In diesem Modeel betrachten wir die Vereinigung von einem Graphen G[alpha] auf n Knoten mit Minimalgrad $[alpha]n and G(n,p). Für ein fixiertes [alpha] > 0, und p = w(n-2/([delta]+1)) zeigen wir mit Böttcher, Montgomery und Person, dass G[alpha] UG(n,p) asymptotisch fast sicher einen beliebigen aufspannenden Graphen auf n Knoten mit Maximalgrad [delta] ernhält, falls [delta] [größer/gleich] 5. Ebenso wie in vorherigen Ergebnissen in diesem Modell ist die Schranke an p um einen log-Faktor kleiner als der vermutete Schwellenwert für das Auftreten dieser Strukturen in G(n,p) alleine. Unsere neue Methode ergibt auch einfachere Beweise für einige verwandte Probleme über Bäume und Faktoren
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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