Search (3 results, page 1 of 1)

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Abstract

Suchmaschinen sind die neuen »Gatekeeper« im Internet. Sie kanalisieren unsere Aufmerksamkeit und haben entscheidenden Einfluss darauf, welche Inhalte wie zugänglich sind. Ohne sie sind Informationen im Netz nur schwer auffindbar. Allerdings: Nur wenige Nutzer wissen, wie man Suchmaschinen optimal bedient und wie sie funktionieren. Sie sind anfällig für Manipulationen (»Spamming«) und verschaffen auch ungewollt Zugang zu illegalen und jugendgefährdenden Inhalten. Wie können Suchmaschinen trotzdem ihrer Verantwortung als zentrale Informationssortierer gerecht werden? Eine groß angelegte Untersuchung der Bertelsmann Stiftung stellt diese Beobachtungen auf eine wissenschaftliche Basis. Eine Nutzerbefragung, ein Laborexperiment und ein Leistungsvergleich geben Aufschluss über Image, Bedienerfreundlichkeit und Qualität von Suchmaschinen. Aus dieser Analyse entwickeln die Autoren einen Code of Conduct für Suchmaschinenbetreiber, der einen möglichst objektiven und transparenten Zugang zu Informationen im Netz garantieren soll. Das Buch ist dreigeteilt: Im ersten umfangreichen Teil (bis Seite 490) werden, nach einer Einführung in die Suchmaschinenproblematik und ihr Umfeld, Qualität und Nutzung erforscht: Nach der Marktanalyse der deutschsprachigen Suchdienste werden ausgewählte einem Leistungsvergleich unterzogen. Der Gefährdung von Kindern und Jugendlichen widmet sich das Kapitel Problemanalyse. Wie erfolgreich Spamversuche die Suchergebnisse beeinflussen können, wird anschließend dargestellt. Den Kenntnissen und Einstellungen von Nutzern von Suchdiensten widmet sich ein ausführliches Kapitel. Nutzungshäufigkeit, Suchprozesse und Vorgehensweisen sind detailliert untersucht worden. Die Ergebnisse der Laborexperimente liefern konkrete Einsichten, auf über 100 Seiten verständlich beschrieben. In Kapitel 6 werden die angewandten Methoden ausführlich erläutert. Das angefügte Glossar könnte ausführlicher sein. Der zweite Teil appelliert an die gesellschaftliche Verantwortung der deutschen Suchdienstbetreiber, indem ein Code of Conduct für Suchmaschinen entworfen wird. Im dritten Teil wird auf die Entwicklungen in der Suchmaschinenlandschaft eingegangen, die sich durch Firmenübernahmen und die Monopolstellung von Google ergeben haben.

Classification

AP 18450 Allgemeines / Medien- und Kommunikationswissenschaften, Kommunikationsdesign / Arten des Nachrichtenwesens, Medientechnik / Telekommunikation, Bildschirmtext

Content

Enthält die Beiträge: Vorwort (Miriam Meckel) Wegweiser im Netz: Qualität und Nutzung von Suchmaschinen (Marcel Machill, Christoph Neuberger, Wolfgang Schweiger, Werner Wirth) Ein Code of Conduct für Suchmaschinen (Carsten Welp) Die Suchmaschinenlandschaft 2003: Wirtschaftliche und technische Entwicklungen (Stefan Karzauninkat)

RVK

AP 18450 Allgemeines / Medien- und Kommunikationswissenschaften, Kommunikationsdesign / Arten des Nachrichtenwesens, Medientechnik / Telekommunikation, Bildschirmtext

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Abstract

Why doesn't your home page appear on the first page of search results, even when you query your own name? How do other Web pages always appear at the top? What creates these powerful rankings? And how? The first book ever about the science of Web page rankings, "Google's PageRank and Beyond" supplies the answers to these and other questions and more. The book serves two very different audiences: the curious science reader and the technical computational reader. The chapters build in mathematical sophistication, so that the first five are accessible to the general academic reader. While other chapters are much more mathematical in nature, each one contains something for both audiences. For example, the authors include entertaining asides such as how search engines make money and how the Great Firewall of China influences research. The book includes an extensive background chapter designed to help readers learn more about the mathematics of search engines, and it contains several MATLAB codes and links to sample Web data sets. The philosophy throughout is to encourage readers to experiment with the ideas and algorithms in the text. Any business seriously interested in improving its rankings in the major search engines can benefit from the clear examples, sample code, and list of resources provided. It includes: many illustrative examples and entertaining asides; MATLAB code; accessible and informal style; and complete and self-contained section for mathematics review.

Content

Inhalt: Chapter 1. Introduction to Web Search Engines: 1.1 A Short History of Information Retrieval - 1.2 An Overview of Traditional Information Retrieval - 1.3 Web Information Retrieval Chapter 2. Crawling, Indexing, and Query Processing: 2.1 Crawling - 2.2 The Content Index - 2.3 Query Processing Chapter 3. Ranking Webpages by Popularity: 3.1 The Scene in 1998 - 3.2 Two Theses - 3.3 Query-Independence Chapter 4. The Mathematics of Google's PageRank: 4.1 The Original Summation Formula for PageRank - 4.2 Matrix Representation of the Summation Equations - 4.3 Problems with the Iterative Process - 4.4 A Little Markov Chain Theory - 4.5 Early Adjustments to the Basic Model - 4.6 Computation of the PageRank Vector - 4.7 Theorem and Proof for Spectrum of the Google Matrix Chapter 5. Parameters in the PageRank Model: 5.1 The a Factor - 5.2 The Hyperlink Matrix H - 5.3 The Teleportation Matrix E Chapter 6. The Sensitivity of PageRank; 6.1 Sensitivity with respect to alpha - 6.2 Sensitivity with respect to H - 6.3 Sensitivity with respect to vT - 6.4 Other Analyses of Sensitivity - 6.5 Sensitivity Theorems and Proofs Chapter 7. The PageRank Problem as a Linear System: 7.1 Properties of (I - alphaS) - 7.2 Properties of (I - alphaH) - 7.3 Proof of the PageRank Sparse Linear System Chapter 8. Issues in Large-Scale Implementation of PageRank: 8.1 Storage Issues - 8.2 Convergence Criterion - 8.3 Accuracy - 8.4 Dangling Nodes - 8.5 Back Button Modeling

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Abstract

The World Wide Web is rapidly filling with more text than anyone could have imagined even a short time ago, but the task of isolating relevant parts of this vast information has become just that much more daunting. Richard Belew brings a cognitive perspective to the study of information retrieval as a discipline within computer science. He introduces the idea of Finding Out About (FDA) as the process of actively seeking out information relevant to a topic of interest and describes its many facets - ranging from creating a good characterization of what the user seeks, to what documents actually mean, to methods of inferring semantic clues about each document, to the problem of evaluating whether our search engines are performing as we have intended. Finding Out About explains how to build the tools that are useful for searching collections of text and other media. In the process it takes a close look at the properties of textual documents that do not become clear until very large collections of them are brought together and shows that the construction of effective search engines requires knowledge of the statistical and mathematical properties of linguistic phenomena, as well as an appreciation for the cognitive foundation we bring to the task as language users. The unique approach of this book is its even handling of the phenomena of both numbers and words, making it accessible to a wide audience. The textbook is usable in both undergraduate and graduate classes on information retrieval, library science, and computational linguistics. The text is accompanied by a CD-ROM that contains a hypertext version of the book, including additional topics and notes not present in the printed edition. In addition, the CD contains the full text of C.J. "Keith" van Rijsbergen's famous textbook, Information Retrieval (now out of print). Many active links from Belew's to van Rijsbergen's hypertexts help to unite the material. Several test corpora and indexing tools are provided, to support the design of your own search engine. Additional exercises using these corpora and code are available to instructors. Also supporting this book is a Web site that will include recent additions to the book, as well as links to sites of new topics and methods.