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Spatial and social diffusion of information and influence: models and algorithmsDoo, Myungcheol 17 May 2012 (has links)
With the ubiquity of broadband, wireless and mobile networking and the diversity of user-driven social networks and social channels, we are entering an information age where people and vehicles are connected at all times, and information and influence are diffused continuously through not only traditional authoritative media such as news papers, TV and radio broadcasting, but also user-driven new channels for disseminating information and diffusing influence. Social network users and mobile travelers can influence and be influenced by the social and spatial connectivity that they share through an impressive array of social and spatial channels, ranging from friendship, activity, professional or social groups to spatial, location-aware, and mobility aware events.
In this dissertation research, we argue that spatial alarms and activity-based social networks are two fundamentally new types of information and influence diffusion channels. Such new channels have the potential of enriching our professional experiences and our personal life quality in many unprecedented ways. For instance, spatial alarms enable people to share their experiences or disseminate certain points of interest by leaving location-dependent greetings, tips or graffiti and location dependent tour guide to their friends, colleagues and family members. Through social networks, people can influence their friends and colleagues by the activities they have engaged, such as reviews and blogs on certain events or products. More interestingly, the power of such spatial and social diffusion of information and influence can go far beyond our physical reach. People can utilize user-generated social and spatial channels as effective means to disseminate information and propagate influence to a much wider and possibly unknown range of audiences and recipients at any time and in any location. A fundamental challenge in embracing such new and exciting ways of information diffusion is to develop effective and scalable models and algorithms as enabling technology and building blocks. This dissertation research is dedicated towards this ultimate objective with three novel and unique contributions.
First, we develop an activity driven and self-configurable social influence model and a suite of computational algorithms to compute and rank social network nodes in terms of activity-based influence diffusion over social network topologies. By activity driven we mean that the real impact of social influence and the speed of such influence propagation should be computed based on the type, the amount and the time window of the activities performed by a social network node in addition to its social connectivity (social network topology). By self-configurable we mean that the diffusion efficiency and effectiveness are dynamically adapted based on the settings and tunings of multiple spatial and social parameters such as diffusion context, diffusion location, diffusion rate, diffusion energy (heat), diffusion coverage and diffusion incentives (e.g., reward points), to name a few. We evaluate our approach through datasets collected from Facebook, Epinions, and DBLP datasets. Our experimental results show that our activity based social influence model outperforms existing topology-based social influence model in terms of effectiveness and quality with respect to influence ranking and influence coverage computation.
Second, we further enhance our activity based social influence model along two dimensions. At first, we use a probabilistic diffusion model to capture the intrinsic properties of social influence such that nodes in a social network may have the choice of whether to participate in a social influence propagation process. We examine threshold based approach and independent probabilistic cascade based approach to determine whether a node is active or inactive in each round of influence diffusion. Secondly, we introduce incentives using multi-scale reward points, which are popularly used in many business settings. We then examine the effectiveness of reward points based incentives in stimulating the diffusion of social influences. We show that given a set of incentives, some active nodes may become more active whereas some inactive nodes may become active. Such dynamics changes the composition of the top-k influential nodes computed by activity-based social influence model. We make several interesting observations: First, popular users who are high degree nodes and have many friends are not necessarily influential in terms of spawning new activities or spreading ideas and information. Second, most influential users are more active in terms of their participation in the social activities and interactions with their friends in the social network. Third, multi-scale reward points based incentives can be effective to both inactive nodes and active nodes.
Third, we introduce spatial alarms as the basic building blocks for location-dependent information sharing and influence diffusion. People can share and disseminate their location based experiences and points of interest to their friends and colleagues in the form of spatial alarms. Spatial alarms are triggered and delivered to the intended subscribers only when the subscribers move into the designated geographical vicinity of the spatial alarms, enabling delivering and sharing of relevant information and experience at the right location and the right time with the right subscribers. We studied how to use locality filters and subscriber filers to enhance the spatial alarm processing using traditional spatial indexing techniques. In addition, we develop a fast spatial alarm indexing structure and algorithms, called Mondrian Tree, and demonstrate that the Mondrian tree enabled spatial alarm system can significantly outperform existing spatial indexing based solutions such as R-tree, $k$-d tree, Quadtree.
This dissertation consists of six chapters. The first chapter introduces the research hypothesis. We describe our activity-based social influence model in Chapter 2. Chapter 3 presents the probabilistic social influence model powered with rewards incentives. We introduce spatial alarms and the basic system architecture for spatial alarm processing in Chapter 4. We describe the design of our Mondrian tree index of spatial alarms and alarm free regions in Chapter 5. In Chapter 6 we conclude the dissertation with a summary of the unique research contributions and a list of open issues closely relevant to the research problems and solution approaches presented in this dissertation.
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Untersuchungen zur Verbesserung der Resultatqualität bei Suchverfahren über Web-ArchiveHofmann, Frank 10 February 2003 (has links) (PDF)
Eine Übersicht über die Verfahren der Erweiterten Suche (TF,IDF, Stemming, Indexing, Klang von Wörtern) sowie Textkorrektur, dazu deskriptorenbasierte Beschreibung von Dokumenten und Abstracts. Es erfolgt eine Evaluierung dieser Verfahren anhand von ausgewählten XML-Metadaten aus dem MONARCH. Den Abschluß bildet eine Analyse zum Ist-Zustand des MONARCH, bezogen auf Qualität der verwendeten Metadaten und deren Nutzbarkeit für die Erweiterte Suche.
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Wie sehr können maschinelle Indexierung und modernes Information Retrieval Bibliotheksrecherchen verbessern?Hauer, Manfred 30 November 2004 (has links) (PDF)
Mit maschinellen Verfahren lässt sich die Qualität der Inhaltserschließung dramatisch steigern. intelligentCAPTURE ist seit 2002 produktiv im Einsatz in Bibliotheken und Dokumentationszentren. Zu dessen Verfahren gehören Module für die Dokumentenakquisition, insbesondere Scanning und OCR, korrekte Textextraktion aus PDF-Dateien und Websites sowie Spracherkennung für "textlose" Objekte. Zusätzliche Verfahren zur Informationsextraktion können optional folgen. Als relevant erkannter Content wird mittels der CAI-Engine (Computer Aided Indexing) maschinell inhaltlich ausgewertet. Dort findet ein Zusammenspiel computerlinguistischer Verfahren (sprachabhängige Morphologie, Syntaxanalyse,
Statistik) und semantischer Strukturen (Klassifikationen, Systematiken,
Thesauri, Topic Maps, RDF, semantische Netze) statt. Aufbereitete Inhalte und fertige, human editierbare Indexate werden schließlich über frei definierbare Exportformate an die jeweiligen Bibliothekssysteme und in der Regel auch an
intelligentSEARCH übergeben. intelligentSEARCH ist eine zentrale Verbunddatenbank zum Austausch zwischen allen produktiven Partnern weltweit aus
dem öffentlichen und privatwirtschaftlichen Bereich. Der Austausch ist auf tauschbare Medien, bislang Inhaltsverzeichnisse, aus urheberrechtlichen Gründen begrenzt. Gleichzeitig ist diese Datenbank "Open Content" für die akademische Öffentlichkeit mit besonders leistungsstarken Retrieval-Funktionen, insbesondere mit semantischen Recherche-Möglichkeiten und der Visualisierung von
semantischen Strukturen (http://www.agi-imc.de/intelligentSEARCH.nsf). Sowohl für die Indexierung als auch für die Recherche können unterschiedliche
semantische Strukturen genutzt werden - je nach Erkenntnisinteresse, Weltsicht oder Sprache.
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Regensburger Verbundklassifikation und Schlagwortnormdatei im TandemProbstmeyer, Judith 24 January 2011 (has links) (PDF)
Im Katalog des Südwestverbunds besitzen zahlreiche Publikationen sowohl SWD-Schlagwörter und -ketten als auch Notationen der Regensburger Verbundklassifikation (RVK). An der Universitätsbibliothek Mannheim wurden auf dieser Datenbasis automatische Korrelationen zwischen SWD und RVK generiert, die im Rahmen einer Bachelorarbeit an der Hochschule der Medien Stuttgart analysiert wurden. Im Vortrag werden die Ergebnisse der Analyse vorgestellt und Überlegungen zu möglichen praktischen Anwendungen solcher Korrelationen angestellt.
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Klassifikationslandschaft aus Schweizer Sicht: UDK, DDC oder RVK -…?Peichl, Gerald, Ruch, Sarah 01 February 2011 (has links) (PDF)
Magazine werden geöffnet, die hauseigene Systematik stößt mit der Zeit an ihre Grenzen oder Einspareffekte durch Fremddaten sollen realisiert werden. Gründe, sich für eine neue oder verbesserte Klassifikation zu entscheiden gibt, es einige. Mit einem Rückblick auf die Geschichte, einem Überblick über die verwendeten Klassifikationen und einer kurzen theoretischen Fundierung zeigen die beiden Vortragenden anhand der RVK und der UDK und aktueller Beispiele aus der Schweiz, welche Klassifikation der richtige Weg in die Zukunft sein könnte.
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Dynamic modeling and analysis for swash-plate type axial pump control utilizing indexing valve plateCho, Junhee, January 2000 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 190-192). Also available on the Internet.
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A GIS-based inventory of terrestrial caves in West Central Florida: Implications on sensitivity, disturbance, ownership and management priorityHarley, Grant L 01 June 2007 (has links)
Active cave management, which represents any continuous action to conserve, restore, or protect a cave environment, is virtually non-existent in west-central Florida. This study focuses on developing an inventory to rank terrestrial caves in west-central Florida by management priority. A GIS-based cave inventory system, including a cave sensitivity index and cave disturbance index, were used as a tool to gain an understanding of the management priority of west-central Florida caves. The inventory was applied to 36 terrestrial caves in west-central Florida, which demonstrated a wide range of sensitivity and disturbance. The results show that by relying solely on sensitivity and disturbance scores, management priority may not be accurately determined. Further examination revealed that ownership and management status also affect management priority. Consequently, cave sensitivity, disturbance, ownership, or management status does not solely indicate management priority. Rather, the management priority of caves in west-central Florida depends on a number of complicated, interwoven factors, and the goal of management must be examined holistically. Each cave must be individually examined for its sensitivity, disturbance, resources, management, and social and physical context in order to gain an understanding of management priority. Nonetheless, the cave inventory system developed for this project was used to gain a general understanding of which caves hold management priority, based on the cave manager's objectives. In order to ensure the conservation and protection of west-central Florida terrestrial caves, support from county or state government, combined with cave inventory data, is crucial in developing sound management policy.
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On the construction and application of compressed text indexesHon, Wing-kai., 韓永楷. January 2004 (has links)
published_or_final_version / abstract / toc / Computer Science and Information Systems / Doctoral / Doctor of Philosophy
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William Stetson Merrill and Bricolage for Information StudiesColeman, Anita Sundaram January 2006 (has links)
This is a preprint published in Journal of Documentation 62 (4): 462-481.
Purpose: This paper examines William Stetson Merrill, the compiler of A Code for Classifiers and a Newberry Library employee (1889-1930) in an attempt to glean lessons for modern information studies from an early librarianâ s career.
Methodology/Approach: Merrillâ s career at the Newberry Library and three editions of the Code are examined using historical, bibliographic, and conceptual methods. Primary and secondary sources in archives and libraries are reviewed to provide insight into Merrillâ s life at the Newberry and his attempts to develop or modify tools to solve the knowledge organization problems he faced. The concept of bricolage, developed by Levi-Strauss to explain modalities of thinking, is applied to Merrillâ s career. Excerpts from his works and reminisces are used to explain Merrill as a bricoleur and highlight the characteristics of bricolage.
Research Implications and Limitations: Findings show that Merrill worked collaboratively to collocate and integrate a variety of ideas from a diverse group of librarians such as Cutter, Pettee, Poole, Kelley, Rudolph, and Fellows. Bliss and Ranganathan were aware of the Code but the extent to which they were influenced by it remains to be explored. Although this is an anachronistic evaluation, Merrill serves as an example of the archetypal information scientist who improvises and integrates methods from bibliography, cataloging, classification, and indexing to solve problems of information retrieval and design usable information products and services for human consumption.
Originality/Value of Paper: Bricolage offers great potential to information practitioners and researchers today as we continue to try and find user-centered solutions to the problems of digital information organization and services.
Paper Type: Research paper
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Modeling the Information-Seeking Behavior of Social Scientists: Ellis's Study RevisitedMeho, Lokman I., Tibbo, Helen R. 04 1900 (has links)
This paper revises David Ellis's information-seeking behavior model of social scientists, which includes six generic features: starting, chaining, browsing, differentiating, monitoring, and extracting. The paper uses social science faculty researching stateless nations as the study population. The description and analysis of the information-seeking behavior of this group of scholars is based on data collected through structured and semistructured electronic mail interviews. Sixty faculty members from 14 different countries were interviewed by e-mail. For reality check purposes, face-to-face interviews with five faculty members were also conducted. Although the study confirmed Ellis's model, it found that a fuller description of the information-seeking process of social scientists studying stateless nations should include four additional features besides those identified by Ellis. These new features are: accessing, networking, verifying, and information managing. In view of that, the study develops a new model, which, unlike Ellis's, groups all the features into four interrelated stages: searching, accessing, processing, and ending. This new model is fully described and its implications on research and practice are discussed. How and why scholars studied here are different than other academic social scientists is also discussed.
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