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Communication patterns abstractions for programming SDN to optimize high-performance computing applications
Get PDFOrientador : Luis Carlos Erpen de BonaCoorientadores : Magnos Martinello; Marcos Didonet Del FabroTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 04/09/2017Inclui referências : f. 95-113Resumo: A evolução da computação e das redes permitiu que múltiplos computadores fossem interconectados, agregando seus poderes de processamento para formar uma computação de alto desempenho (HPC). As aplicações que são executadas nesses ambientes processam enormes quantidades de informação, podendo levar várias horas ou até dias para completar suas execuções, motivando pesquisadores de varias áreas computacionais a estudar diferentes maneiras para acelerá-las. Durante o processamento, essas aplicações trocam grandes quantidades de dados entre os computadores, fazendo que a rede se torne um gargalo. A rede era considerada um recurso estático, não permitindo modificações dinâmicas para otimizar seus links ou dispositivos. Porém, as redes definidas por software (SDN) emergiram como um novo paradigma, permitindoa ser reprogramada de acordo com os requisitos dos usuários. SDN já foi usado para otimizar a rede para aplicações HPC específicas mas nenhum trabalho tira proveito dos padrões de comunicação expressos por elas. Então, o principal objetivo desta tese é pesquisar como esses padrões podem ser usados para ajustar a rede, criando novas abstrações para programá-la, visando acelerar as aplicações HPC. Para atingir esse objetivo, nós primeiramente pesquisamos todos os níveis de programabilidade do SDN. Este estudo resultou na nossa primeira contribuição, a criação de uma taxonomia para agrupar as abstrações de alto nível oferecidas pelas linguagens de programação SDN. Em seguida, nós investigamos os padrões de comunicação das aplicações HPC, observando seus comportamentos espaciais e temporais através da análise de suas matrizes de tráfego (TMs). Concluímos que as TMs podem representar as comunicações, além disso, percebemos que as aplicações tendem a transmitir as mesmas quantidades de dados entre os mesmos nós computacionais. A segunda contribuição desta tese é o desenvolvimento de um framework que permite evitar os fatores da rede que podem degradar o desempenho das aplicações, tais como, sobrecarga imposta pela topologia, o desbalanceamento na utilização dos links e problemas introduzidos pela programabilidade do SDN. O framework disponibiliza uma API e mantém uma base de dados de TMs, uma para cada padrão de comunicação, anotadas com restrições de largura de banda e latência. Essas informações são usadas para reprogramar os dispositivos da rede, alocando uniformemente as comunicações nos caminhos da rede. Essa abordagem reduziu o tempo de execução de benchmarks e aplicações reais em até 26.5%. Para evitar que o código da aplicação fosse modificado, como terceira contribuição, desenvolvemos um método para identificar automaticamente os padrões de comunicação. Esse método gera texturas visuais di_erentes para cada TM e, através de técnicas de aprendizagem de máquina (ML), identifica as aplicações que estão usando a rede. Em nossos experimentos, o método conseguiu uma taxa de acerto superior a 98%. Finalmente, nós incorporamos esse método ao framework, criando uma abstração que permite programar a rede sem a necessidade de alterar as aplicações HPC, diminuindo em média 15.8% seus tempos de execução. Palavras-chave: Redes Definidas por Software, Padrões de Comunicação, Aplicações HPC.Abstract: The evolution of computing and networking allowed multiple computers to be interconnected, aggregating their processing powers to form a high-performance computing (HPC). Applications that run in these computational environments process huge amounts of information, taking several hours or even days to complete their executions, motivating researchers from various computational fields to study different ways for accelerating them. During the processing, these applications exchange large amounts of data among the computers, causing the network to become a bottleneck. The network was considered a static resource, not allowing dynamic adjustments for optimizing its links or devices. However, Software-Defined Networking (SDN) emerged as a new paradigm, allowing the network to be reprogrammed according to users' requirements. SDN has already been used to optimize the network for specific HPC applications, but no existing work takes advantage of the communication patterns expressed by those applications. So, the main objective of this thesis is to research how these patterns can be used for tuning the network, creating new abstractions for programming it, aiming to speed up HPC applications. To achieve this goal, we first surveyed all SDN programmability levels. This study resulted in our first contribution, the creation of a taxonomy for grouping the high-level abstractions offered by SDN programming languages. Next, we investigated the communication patterns of HPC applications, observing their spatial and temporal behaviors by analyzing their traffic matrices (TMs). We conclude that TMs can represent the communications, furthermore, we realize that the applications tend to transmit the same amount of data among the same computational nodes. The second contribution of this thesis is the development of a framework for avoiding the network factors that can degrade the performance of applications, such as topology overhead, unbalanced links, and issues introduced by the SDN programmability. The framework provides an API and maintains a database of TMs, one for each communication pattern, annotated with bandwidth and latency constraints. This information is used to reprogram network devices, evenly placing the communications on the network paths. This approach reduced the execution time of benchmarks and real applications up to 26.5%. To prevent the application's source code to be modified, as a third contribution of our work, we developed a method to automatically identify the communication patterns. This method generates different visual textures for each TM and, through machine learning (ML) techniques, identifies the applications using the network. In our experiments the method succeeded with an accuracy rate over 98%. Finally, we incorporate this method into the framework, creating an abstraction that allows programming the network without changing the HPC applications, reducing on average 15.8% their execution times. Keywords: Software-Defined Networking, Communication Patterns, HPC Applications
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
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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