1,720,969 research outputs found
Flexible semantic service execution
No full textZusammenfassung: Die vorliegende Arbeit widmet sich einer wichtigen Aufgabenstellung, die im Umfeld verteilter und dienstbasierter Architekturen auftritt: Die korrekte, zuverlässige und effiziente Ausführung softwarebasierter Dienste. Im Zentrum dieser Arbeit stehen dabei zwei Ansätze die jeweils die Flexibilität bei der Umsetzung dieser Aufgabe steigern. Erstens eine neuartige Methode zur automatisierten Vorwärtsbehandlung von Dienstfehlern zur Ausführungszeit, genannt Control Flow Intervention (CFI). Zweitens eine in sich geschlossene Ausführungstechnik die die Migration laufender Ausführungsinstanzen zwischen verfügbaren Ausführungsmaschinen gestattet. Beide tragen den spezifischen Anforderungen neuartiger internetbasierter und mobiler Anwendungsgebiete Rechnung. Wesentliche Merkmale dieser Anwendungen sind (i) Inhärenz entfernter Aufrufe, (ii) ad-hoc-Dienste um dynamisch sich verändernden Umgebungen und Benutzerpräferenzen gerecht zu werden und (iii) eine hohe Fehleranfälligkeit bedingt durch drahtlose Verbindungen und Volatilität angebotener Dienste.
Die zugrunde liegende Theorie für alle in dieser Arbeit angestellten Untersuchungen sind Semantische Dienste, insbesondere basierend auf deduktiven und entscheidbaren Beschreibungslogiken. In einem ersten Schritt greifen wir bisherige Arbeiten aus diesem Bereich auf und entwickeln diese weiter hin zu einem kohärenten formalen Systemmodell welches wesentliche Dimensionen in der Semantik von Diensten vereint.
Basierend auf diesem Systemmodell liegt anschliessend das Hauptaugenmerk auf CFI. Ziel dieser Methode ist es, Dienstfehler durch geeignete Ersetzungsstrategien nach vorn zu korrigieren, so dass das geplante Gesamtziel eines Dienstes in äquivalenter oder zumindest vergleichbarer Form trotzdem erreicht werden kann. Dies wird durch dynamisches Ausweichen auf semantisch äquivalente oder ähnliche Alternativen ermöglicht. Hierbei wird davon ausgegangen, dass konkrete Alternativen nicht Bestandteil der Dienstspezifikation sind. Es wird lediglich angenommen, dass sie in der Anwendungsdomäne vorhanden sind. Da Alternativen somit nicht vordefiniert sind, wird im Fehlerfall dynamisch nach ihnen gesucht.
Da das vorgestellte Systemmodell zwei Arten von Nebenläufigkeit bei der Dienstausführung zulässt, und da die Repräsentation des Zustandes verschiedener Ausführungsinstanzen in einer gemeinsamen Wissensbasis erfolgt, wird ausserdem der korrekte und inferenzvermeidende simultane Zugriff auf solche Wissensbasen untersucht. Diese Arbeit stellt dazu ein neuartiges Zugriffsmodell zur Koordination von nebenläufigen Transaktionen auf einer Web Ontology Language Wissensbasis vor. In diesem Zusammenhang werden dessen Leistungs- und Isolationseigenschaften diskutiert.
Um die praktische Anwendbarkeit der entwickelten Methoden untersuchen zu können, wurden diese prototypisch in unserem verteilten und dezentralen Ausführungssystem OSIRIS Next implementiert. Wir beschreiben den grundlegenden Aufbau dieses Systems. In diesem Zusammenhang stellt diese Arbeit dann die verteilte Ausführungstechnik vor, die insbesondere für (semi-)automatisch zusammengefügte und nur wenige Male ausgeführte ad-hoc-Dienste optimiert ist.
Schliesslich wurden die vorgestellten Verfahren durch verschiedene Experimente hinsichtlich ihres Laufzeitverhaltens quantitativ evaluiert. Die dabei gemachten Erfahrungen und Resultate zeigen das Potential der Verfahren für deren Einsatz in der Praxis.
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Abstract: This thesis deals with an important task in the context of distributed and service-oriented architectures: the correct, reliable, and efficient execution of software-based services. In the center of this work are two approaches that increase the flexibility in this task. First, a novel method for automated forward recovery of service failures at execution time, called Control Flow Intervention (CFI). Second, a self-contained technique that allows for migration of running execution instances among available execution machines. Both address requirements specific to novel Internet-based and mobile applications. Characteristic for such applications are (i) inherent remote invocation, (ii) ad-hoc services to cope with dynamically changing environments and user preferences, and (iii) frequent errors due to wireless connections and volatility of offered services.
The underlying theory for all investigations made in this thesis are Semantic Services, based in particular on deductive and decidable Description Logics. In a first step, we take up prior work in this area and develop it further towards a coherent formal system model that combines essential dimensions of service semantics.
Based on this model, the focus is then on CFI. The goal of this method is to correct service failures by appropriate replacement strategies in a forward-oriented way, meaning that the overall goal of a service remains attainable, though in a semantically equivalent or at least comparable form. This is achieved by dynamically shifting to semantically equivalent or similar alternatives. Alternatives are however not pre-defined as part of the service specification. Rather, it is assumed that they exist in the application domain and that they are searched for on demand in the presence of a failure.
Since the system model allows for two types of concurrency in the service execution, and since the state of execution instances is represented in a shared knowledge base, we also investigate the problem of ensuring correct concurrent access to knowledge bases so that inferences are avoided. Specifically, we present a novel concurrency control model for transactions operating over a Web Ontology Language knowledge base. Efficiency and isolation properties of the presented approach are furthermore discussed.
In order to investigate the practical applicability of the presented methods, they were prototypically implemented in our distributed and decentralized execution system OSIRIS Next. We describe the architecture of this system. In this context, the distributed execution technique is presented that is particularly optimized for ad-hoc services that are usually (semi-)automatically composed and executed a few times only.
Finally, the presented methods were evaluated quantitatively by various experiments with respect to their runtime behavior. The results and the experiences gained show the potential of the methods for their application in practice
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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