1,720,960 research outputs found
Spanning subgraphs in graphs and hypergraphs
No full textThis thesis consists of three new fundamental results on the existence of spanning subgraphs in graphs and hypergraphs. Cycle Factors in Graphs: A classical conjecture of El-Zahar states that if H is a graph consisting of r vertex disjoint cycles of length n_1, n_2, ldots , n_r, and G is a graph on n = n_1+n_2 + ... +n_r vertices with minimum degree at least [sigmar/i=1 n_1/2
then G contains H as a subgraph. A proof of this conjecture for graphs withn[greater than or less than] n_0 was announced by S. Abbasi (1998) using the Regularity Lemma-Blow-up Lemma method. We give a new, ``de-regularized" proof of the conjecture for large graphs that avoids the use of the Regularity Lemma, and thus the resulting n_0 is much smaller. Perfect Matching in three-uniform hypergraphs A perfect matching in a three-uniform hypergraph on n=3k vertices is a subset of n/3 disjoint edges. We prove that if is a three-uniform hypergraph on vertices such that every vertex belongs to at least {n-1choose 2} - {2n/3choose 2}+1 edges, then H contains a perfect matching. We give a construction to show that our result is best possible. Perfect Matching in four-uniform hypergraphs A perfect matching in a four-uniform hypergraph is a subset of lfloorfrac{n}{4}
floor disjoint edges. We prove that if H is a sufficiently large four-uniform hypergraph on n=4k vertices such that every vertex belongs to more than ${n-1choose 3} - {3n/4 choose 3} edges, then H contains a perfect matching. Our bound is tight and settles a conjecture of Hán, Person and Schacht (2009).Ph.D.Includes bibliographical referencesIncludes vitaby Imdadullah Kha
Tree Packing in Complete Graph
No full textA conjecture of Gy´arf´as and Lehel asks if the sequence of trees T1, T2, ..., Tn, where Ti is a tree on i vertices, can be packed into Kn. We show that if each Ti is restricted to a star or a path, then the sequence can be packed. We also give an explicit construction for a restricted case when the paths and stars alternate.Technical report DCS-TR-68
Generalized Similarity Kernels for Efficient Sequence Classification
No full textString kernel-based machine learning methods have yielded great success in practical tasks of structured/sequential data analysis. In this paper we propose a novel computational framework that uses general similarity metrics and distance-preserving embeddings with string kernels to improve sequence classification. An embedding step, a distance-preserving bitstring mapping, is used to effectively capture similarity between otherwise symbolically different sequence elements. We show that it is possible to retain computational efficiency of string kernels while using this more “precise” measure of similarity. We then demonstrate that on a number of sequence classification tasks such as music, and biological sequence classification, the new method can substantially improve upon state-of-the-art string kernel baselines.Technical report DCS-TR-68
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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