1,720,966 research outputs found
Effizientes Datenmanagement in drahtlosen Sensornetzen durch Peer-to-Peer Methoden
No full textThe data-centric nature of Wireless Sensor Networks (WSNs) and the severe resource constraints of the sensor nodes distinguish sensor data management from other communication networks. Both the client-server approach as well as the end-to-end communication principle that have been proposed in the for Mobile Ad Hoc Networks (MANETs) do not suit the characteristics of WSNs. Efficient lookup and routing of sensor data are of great significance for WSNs, especially as the size of these networks continues to grow. On an abstract level, structured peer-to-peer protocols, which rely on Distributed Hash Tables (DHTs) provide O(1) complexity for storing and retrieving data in the network, seem overcome these restrictions. However, the fact that they rely on underlayer routing techniques leads to inefficient resource usage in the context of sensor networks. The combination of DHTs and underlayer routing led to the establishment of so called virtual coordinate routing techniques. Most of these algorithms are quite complicated and do not guarantee packet delivery on the shortest path. Additionally, only few of them are implemented in real sensor nodes. In this dissertation, we present the Virtual Cord Protocol (VCP), a virtual position based routing protocol that also provides means for data management such as identifying, storing, and retrieving data items. The key contributions of this protocol are independence of real location information by relying on virtual relative positions of neighboring nodes, the simplicity of obtaining the virtual positions, near optimal routing paths, and high scalability because only information about direct neighbors is needed for routing. Furthermore, VCP provides a unique position for each node and inherently prevents dead-ends. We extensively evaluated VCP in a number of simulation experiments. The simulation results show that VCP consistently provides high throughput and low overhead for a wide range of application scenarios. We compared VCP with Dynamic MANET on Demand (DYMO), a typical MANET protocol, and with Virtual Ring Routing (VRR), another virtual coordinate based approach. In static networks, both VCP and VRR clearly outperform DYMO. In the case of frequent node failures, however, VCP benefits from its light-weight design. Our protocol is more failure tolerant compared to VRR. We finally integrated data replication techniques that support high success rates even in very unreliable sensor networks. A prototype implementation on real sensor nodes outlines the feasibility of our approach in a proof-of-concept study.Die datenzentrische Arbeitsweise von drahtlosen Sensornetzen sowie die kritischen Ressourcenbeschränkungen von Sensorknoten unterscheiden die Datenverarbeitung in diesem Bereich von klassischen Kommunikationsnetzen. Sowohl der Client-Server- Ansatz als auch die Ende-zu-Ende Kommunikationsparadigmen, welche u.a. auch für mobile ad-hoc Netze erfolgreich eingesetzt werden, sind nur bedingt für Sensornetze nutzbar. Von besonderer Bedeutung in Sensornetzen sind effiziente Identifikations und Routingmethoden. Dies betrifft vor allem die Skalierbarkeit für größer werdende Netze. Auf einer abstrakten Ebene scheinen strukturierte Peer-to-Peer-Ansätze eine Alternative darzustellen, da durch den Einsatz verteilter Hash-Tabellen eine O(1) Komplexität für die Identifikation von Daten erreicht werden kann. Allerdings bedürfen diese Verfahren einer stabilen Routing-Infrastruktur auf den unteren Schichten. Die Kombination von verteilten Hash-Tabellen und Routingverfahren führte zur Entwicklung sogenannter Virtuelle-Coordinaten-Algorithmen. Viele dieser Methoden sind allerdings sehr kompliziert und geben keine Garantie für den Datenversand auf einem kürzesten Weg. Weiterhin sind nur wenige in einer realen Sensorumgebung implementiert. In dieser Dissertation wird das Virtual Cord Protocol (VCP) vorgestellt, welches virtuelle Knotenpositionen für das Datenmanagement und den Datentransport einsetzt. Die wesentlichen Beiträge können wie folgt zusammengefasst werden: Unabhängigkeit des Protokolls von realen Knotenpositionen, einfache Definition und Verwaltung der virtuellen Koordinaten, kurze Routingpfade nahe dem kürzesten Weg, hohe Skalierbarkeit durch die Beschränkung auf lokal verfügbare Nachbarschaftsinformationen. Weiterhin verwaltet VCP eindeutige Knotenadressen und vermeidet konzeptuell mögliche Sackgassen. VCP wurde im Rahmen der Arbeit in umfangreichen Simulationsexperimenten bewertet. Die Ergebnisse zeigen, dass VCP hohen Durchsatz und geringe Kosten für einen breiten Einsatzbereich ermöglicht. In einem direkten Vergleich mit Dynamic MANET on Demand (DYMO), einem typischen ad-hoc Routing Protokoll, sowie Virtual Ring Routing (VRR), einem kompetitiven Ansatz basierend auf virtuellen Koordinaten, zeigte sich, dass VCP und VRR in statischen klassischen ad-hoc Verfahren überlegen sind. Für dynamische Netze mit häufig ausfallenden Knoten dominiert allerdings VCP durch sein leichtgewichtiges Design. Das Protokoll ist stärker fehlertolerant als VRR. Weiterhin wurden Replikationsmethoden integriert, die hervorragende Erfolgsraten auch in sehr unzuverlässigen Sensornetzen ermöglichen. Ein implementierter Prototyp zeigt die Fähigkeiten des neuen Ansatzes in einer Proof-of-Concept Studie
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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