1,721,044 research outputs found
Topological optimization of fault-tolerant networks meeting reliability constraints.
No full textThe relevant entities in a network are its nodes, and the links between them. In general, the goal is to achieve a reliable communication between dierent pairs of nodes. Examples of applications are telephonic services, data communication, transportation systems, computer systems, electric networks and control systems. The predominant criterion for the design of a reliable and survivable system is the minimum-cost in most contexts. An attractive topic for research is to consider a minimum-cost topological optimization design meeting a reliability threshold. Even though the cost has been the primary factor in the network design, recently, the network reliability has grown in relevance. With the progress of Fiber-To-the-Home (FTTH) services for the backbone design in most current networks, combined with the rapid development of network communication technologies, and the explosive increase of applications over the Internet infrastructure, the network reliability has supreme importance, for traditional communication systems but for the defense, business and energy, and emergent elds such as trusted computing, cloud computing, Internet of Things (IoT) and Next Generation Networks (NGN), the fault tolerance is critical. We can distinguish two main problems to address in the analysis and design of network topologies. First, the robustness is usually met under multi-path generation. Therefore, we require certain number of node-disjoint paths between distinguished nodes, called terminals. The second problem is to meet a minimum-reliability requirement in a hostile environment, using the fact that both nodes and links may fail. Both problems are strongly related, where sometimes the minimum-cost topology already meets the reliability threshold, or it should be discarded, and the design is challenging. This thesis deals with a topological optimization problem meeting reliability constraints. The Generalized Steiner Problem with Node-Connectivity Constraints and Hostile Reliability (GSP-NCHR) is introduced, and it is an extension of the well-known Generalized Steiner Problem (GSP). Since GSP-NCHR subsumes the GSP, it belongs to the class of N P-Hard problems. A full chapter is dedicated to the hardness of the GSP-NCHR, and an analysis of particular sub-problems. Here, the GSP-NCHR is addressed approximately. Our goal is to meet the topological x requirements intrinsically considered in the GSP-NCHR, and then test if the resulting topology meets a minimum reliability constraint. As a consequence a hybrid heuristic is proposed, that considers a Greedy Randomized construction phase followed by a Variable Neighborhood Search (VNS) in a second phase. VNS is a powerful method that combines local searches that consider dierent neighborhood structures, and it was used to provide good solutions in several hard combinatorial optimization problems. Since the reliability evaluation in the hostile model belongs to the class of N P-Hard problems, a pointwise reliability estimation was adopted. Here we considered Recursive Variance Reduction method (RVR), since an exact reliability evaluation is prohibitive for large-sized networks. The experimental analysis was carried out on a wide family of instances adapted from travel salesman problem library (TSPLIB), for heterogeneous networks with dierent characteristics and topologies, including up to 400 nodes. The numerical results show acceptable CPU-times and locally-optimum solutions with good quality, meeting network reliability constraints as well.En una red las entidades relevantes son nodos y conexiones entre nodos, y en general el principal objetivo buscado es lograr una comunicación segura entre nodos de esta red, ya sea para redes telefónicas y de comunicación de datos, de transporte, arquitectura de computadores, redes de energía eléctrica o sistemas de comando y control. La optimización relativa al costo de una red y la contabilidad de la misma, relacionada con la supervivencia de esta, son los criterios predominantes en la selección de una solución para la mayor parte de los contextos. Un tema interesante que ha atraído un gran esfuerzo es cómo diseñar topologías de red, con un uso mínimo de recursos de red en términos de costo que brinde una garantía de contabilidad. A pesar que por años el costo ha sido el factor primario, la contabilidad ha ganado rápidamente en relevancia. Con sistemas de transmisión de fibra óptica de alta capacidad formando la columna vertebral de la mayoría de las redes actuales y junto con el rápido desarrollo de la tecnología de comunicación de redes y el crecimiento explosivo de las aplicaciones de Internet, la contabilidad de la red parece cada vez más importante, tanto para áreas tradicionales como la industria de defensa, finanzas y energía, y áreas emergentes como la computación contable, la computación en la nube, internet de las cosas (IoT) y la próxima generación de Internet, la supervivencia del tráfico por sobre los fallos de red se ha convertido aún en más crítica. En ese sentido podemos diferenciar, a grandes rasgos, dos de los principales problemas a resolver en el análisis y diseño de topologías de red. Primeramente la obtención de una red óptima en algún sentido, siendo este definido por ejemplo mediante la obtención de la máxima cantidad posible de caminos disjuntos entre pares de nodos, esto sujeto a determinadas restricciones definidas según el contexto. El segundo problema es la evaluación de la contabilidad de la red en función de las contabilidades elementales de los nodos y conexiones entre nodos que componen la red. Estas contabilidades elementales son probabilidades de operación asociadas a los nodos y conexiones entre nodos. Ambos problemas están fuertemente relacionados, pudiendo tener que comparar en el proceso de búsqueda de redes óptimas la contabilidad entre soluciones candidatas, o luego de obtener una solución candidata tener que evaluar la contabilidad de la misma y de esta forma descartarla o no. El presente trabajo se centra en la resolución del problema enfocado en ambos puntos planteados. Para ello modelamos el problema de diseño de la topología de red sobre la base de un modelo de nido como Generalized Steiner Problem with Node-Connectivity Constraints and Hostile Reliability (GSP-NCHR) extensión del más conocido Generalized Steiner Problem (GSP). El presente problema es NP-duro, dedicamos un capítulo para presentar resultados teóricos que lo demuestran. Nuestro objetivo es atacar de forma aproximada el modelo GSP-NCHR de tal modo de poder resolver la optimización de la red y luego medir la contabilidad de la solución obtenida. Para ello optamos por desarrollar la metaheurística Variable Neighborhood Search (VNS). VNS es un método potente que combina el uso de búsquedas locales basadas en distintas definiciones de vecindad, el cual ha sido utilizado para obtener soluciones de buena calidad en distintos problemas de optimización combinatoria. En lo referente al cálculo de contabilidad de la red, nuestro modelo GSP-NCHR pertenece a la clase NP-duro, por eso desarrollamos Recursive Variance Reduction (RVR) como método de simulación, ya que la evaluación exacta de esta medida para redes de tamaño considerable es impracticable. Las pruebas experimentales fueron realizadas utilizando un conjunto amplio de casos de prueba adaptados de la librería travel salesman problem (TSPLIB), de heterogéneas topologías con diferentes características, incluyendo instancias de hasta 400 nodos. Los resultados obtenidos indican tiempos de cómputo altamente aceptables acompañados de óptimos locales de buena calidad
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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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