Langville, A.N.; Meyer, C.D.: Google's PageRank and beyond : the science of search engine rankings (2006)
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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
Chapter 9. Accelerating the Computation of PageRank: 9.1 An Adaptive Power Method - 9.2 Extrapolation - 9.3 Aggregation - 9.4 Other Numerical Methods Chapter 10. Updating the PageRank Vector: 10.1 The Two Updating Problems and their History - 10.2 Restarting the Power Method - 10.3 Approximate Updating Using Approximate Aggregation - 10.4 Exact Aggregation - 10.5 Exact vs. Approximate Aggregation - 10.6 Updating with Iterative Aggregation - 10.7 Determining the Partition - 10.8 Conclusions Chapter 11. The HITS Method for Ranking Webpages: 11.1 The HITS Algorithm - 11.2 HITS Implementation - 11.3 HITS Convergence - 11.4 HITS Example - 11.5 Strengths and Weaknesses of HITS - 11.6 HITS's Relationship to Bibliometrics - 11.7 Query-Independent HITS - 11.8 Accelerating HITS - 11.9 HITS Sensitivity Chapter 12. Other Link Methods for Ranking Webpages: 12.1 SALSA - 12.2 Hybrid Ranking Methods - 12.3 Rankings based on Traffic Flow Chapter 13. The Future of Web Information Retrieval: 13.1 Spam - 13.2 Personalization - 13.3 Clustering - 13.4 Intelligent Agents - 13.5 Trends and Time-Sensitive Search - 13.6 Privacy and Censorship - 13.7 Library Classification Schemes - 13.8 Data Fusion Chapter 14. Resources for Web Information Retrieval: 14.1 Resources for Getting Started - 14.2 Resources for Serious Study Chapter 15. The Mathematics Guide: 15.1 Linear Algebra - 15.2 Perron-Frobenius Theory - 15.3 Markov Chains - 15.4 Perron Complementation - 15.5 Stochastic Complementation - 15.6 Censoring - 15.7 Aggregation - 15.8 Disaggregation
Broughton, V.: Essential thesaurus construction (2006)
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- Abstract
- Many information professionals working in small units today fail to find the published tools for subject-based organization that are appropriate to their local needs, whether they are archivists, special librarians, information officers, or knowledge or content managers. Large established standards for document description and organization are too unwieldy, unnecessarily detailed, or too expensive to install and maintain. In other cases the available systems are insufficient for a specialist environment, or don't bring things together in a helpful way. A purpose built, in-house system would seem to be the answer, but too often the skills necessary to create one are lacking. This practical text examines the criteria relevant to the selection of a subject-management system, describes the characteristics of some common types of subject tool, and takes the novice step by step through the process of creating a system for a specialist environment. The methodology employed is a standard technique for the building of a thesaurus that incidentally creates a compatible classification or taxonomy, both of which may be used in a variety of ways for document or information management. Key areas covered are: What is a thesaurus? Tools for subject access and retrieval; what a thesaurus is used for? Why use a thesaurus? Examples of thesauri; the structure of a thesaurus; thesaural relationships; practical thesaurus construction; the vocabulary of the thesaurus; building the systematic structure; conversion to alphabetic format; forms of entry in the thesaurus; maintaining the thesaurus; thesaurus software; and; the wider environment. Essential for the practising information professional, this guide is also valuable for students of library and information science.
- Footnote
- Rez. in: Mitt. VÖB 60(2007) H.1, S.98-101 (O. Oberhauser): "Die Autorin von Essential thesaurus construction (and essential taxonomy construction, so der implizite Untertitel, vgl. S. 1) ist durch ihre Lehrtätigkeit an der bekannten School of Library, Archive and Information Studies des University College London und durch ihre bisherigen Publikationen auf den Gebieten (Facetten-)Klassifikation und Thesaurus fachlich einschlägig ausgewiesen. Nach Essential classification liegt nun ihr Thesaurus-Lehrbuch vor, mit rund 200 Seiten Text und knapp 100 Seiten Anhang ein handliches Werk, das seine Genese zum Grossteil dem Lehrbetrieb verdankt, wie auch dem kurzen Einleitungskapitel zu entnehmen ist. Das Buch ist der Schule von Jean Aitchison et al. verpflichtet und wendet sich an "the indexer" im weitesten Sinn, d.h. an alle Personen, die ein strukturiertes, kontrolliertes Fachvokabular für die Zwecke der sachlichen Erschliessung und Suche erstellen wollen bzw. müssen. Es möchte dieser Zielgruppe das nötige methodische Rüstzeug für eine solche Aufgabe vermitteln, was einschliesslich der Einleitung und der Schlussbemerkungen in zwanzig Kapiteln geschieht - eine ansprechende Strukturierung, die ein wohldosiertes Durcharbeiten möglich macht. Zu letzterem tragen auch die von der Autorin immer wieder gestellten Übungsaufgaben bei (Lösungen jeweils am Kapitelende). Zu Beginn der Darstellung wird der "information retrieval thesaurus" von dem (zumindest im angelsächsischen Raum) weit öfter mit dem Thesaurusbegriff assoziierten "reference thesaurus" abgegrenzt, einem nach begrifflicher Ähnlichkeit angeordneten Synonymenwörterbuch, das gerne als Mittel zur stilistischen Verbesserung beim Abfassen von (wissenschaftlichen) Arbeiten verwendet wird. Ohne noch ins Detail zu gehen, werden optische Erscheinungsform und Anwendungsgebiete von Thesauren vorgestellt, der Thesaurus als postkoordinierte Indexierungssprache erläutert und seine Nähe zu facettierten Klassifikationssystemen erwähnt. In der Folge stellt Broughton die systematisch organisierten Systeme (Klassifikation/ Taxonomie, Begriffs-/Themendiagramme, Ontologien) den alphabetisch angeordneten, wortbasierten (Schlagwortlisten, thesaurusartige Schlagwortsysteme und Thesauren im eigentlichen Sinn) gegenüber, was dem Leser weitere Einordnungshilfen schafft. Die Anwendungsmöglichkeiten von Thesauren als Mittel der Erschliessung (auch als Quelle für Metadatenangaben bei elektronischen bzw. Web-Dokumenten) und der Recherche (Suchformulierung, Anfrageerweiterung, Browsing und Navigieren) kommen ebenso zur Sprache wie die bei der Verwendung natürlichsprachiger Indexierungssysteme auftretenden Probleme. Mit Beispielen wird ausdrücklich auf die mehr oder weniger starke fachliche Spezialisierung der meisten dieser Vokabularien hingewiesen, wobei auch Informationsquellen über Thesauren (z.B. www.taxonomywarehouse.com) sowie Thesauren für nicht-textuelle Ressourcen kurz angerissen werden.
Weitere Rez. in: New Library World 108(2007) nos.3/4, S.190-191 (K.V. Trickey): "Vanda has provided a very useful work that will enable any reader who is prepared to follow her instruction to produce a thesaurus that will be a quality language-based subject access tool that will make the task of information retrieval easier and more effective. Once again I express my gratitude to Vanda for producing another excellent book." - Electronic Library 24(2006) no.6, S.866-867 (A.G. Smith): "Essential thesaurus construction is an ideal instructional text, with clear bullet point summaries at the ends of sections, and relevant and up to date references, putting thesauri in context with the general theory of information retrieval. But it will also be a valuable reference for any information professional developing or using a controlled vocabulary." - KO 33(2006) no.4, S.215-216 (M.P. Satija)
