Search (8 results, page 1 of 1)

  • × year_i:[2000 TO 2010}
  • × author_ss:"Lewandowski, D."
  1. Lewandowski, D.: Alles nur noch Google? : Entwicklungen im Bereich der WWW-Suchmaschinen (2002) 0.00 
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    Date
    29. 9.2002 18:49:22
  2. Lewandowski, D.: Abfragesprachen und erweiterte Funktionen von WWW-Suchmaschinen (2004) 0.00 
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    Date
    28.11.2004 13:11:22
  3. Lewandowski, D.; Mayr, P.: Exploring the academic invisible Web (2006) 0.00 
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    Abstract
    Purpose: To provide a critical review of Bergman's 2001 study on the Deep Web. In addition, we bring a new concept into the discussion, the Academic Invisible Web (AIW). We define the Academic Invisible Web as consisting of all databases and collections relevant to academia but not searchable by the general-purpose internet search engines. Indexing this part of the Invisible Web is central to scien-tific search engines. We provide an overview of approaches followed thus far. Design/methodology/approach: Discussion of measures and calculations, estima-tion based on informetric laws. Literature review on approaches for uncovering information from the Invisible Web. Findings: Bergman's size estimate of the Invisible Web is highly questionable. We demonstrate some major errors in the conceptual design of the Bergman paper. A new (raw) size estimate is given. Research limitations/implications: The precision of our estimate is limited due to a small sample size and lack of reliable data. Practical implications: We can show that no single library alone will be able to index the Academic Invisible Web. We suggest collaboration to accomplish this task. Originality/value: Provides library managers and those interested in developing academic search engines with data on the size and attributes of the Academic In-visible Web.
    Content
    Bezug zu: Bergman, M.K.: The Deep Web: surfacing hidden value. In: Journal of Electronic Publishing. 7(2001) no.1, S.xxx-xxx. [Vgl. unter: http://www.press.umich.edu/jep/07-01/bergman.html].
  4. Lewandowski, D.; Mayr, P.: Exploring the academic invisible Web (2006) 0.00 
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    Abstract
    Purpose: To provide a critical review of Bergman's 2001 study on the deep web. In addition, we bring a new concept into the discussion, the academic invisible web (AIW). We define the academic invisible web as consisting of all databases and collections relevant to academia but not searchable by the general-purpose internet search engines. Indexing this part of the invisible web is central to scientific search engines. We provide an overview of approaches followed thus far. Design/methodology/approach: Discussion of measures and calculations, estimation based on informetric laws. Literature review on approaches for uncovering information from the invisible web. Findings: Bergman's size estimate of the invisible web is highly questionable. We demonstrate some major errors in the conceptual design of the Bergman paper. A new (raw) size estimate is given. Research limitations/implications: The precision of our estimate is limited due to a small sample size and lack of reliable data. Practical implications: We can show that no single library alone will be able to index the academic invisible web. We suggest collaboration to accomplish this task. Originality/value: Provides library managers and those interested in developing academic search engines with data on the size and attributes of the academic invisible web.
  5. Lewandowski, D.: How can library materials be ranked in the OPAC? (2009) 0.00 
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    Abstract
    Some Online Public Access Catalogues offer a ranking component. However, ranking there is merely text-based and is doomed to fail due to limited text in bibliographic data. The main assumption for the talk is that we are in a situation where the appropriate ranking factors for OPACs should be defined, while the implementation is no major problem. We must define what we want, and not so much focus on the technical work. Some deep thinking is necessary on the "perfect results set" and how we can achieve it through ranking. The talk presents a set of potential ranking factors and clustering possibilities for further discussion. A look at commercial Web search engines could provide us with ideas how ranking can be improved with additional factors. Search engines are way beyond pure text-based ranking and apply ranking factors in the groups like popularity, freshness, personalisation, etc. The talk describes the main factors used in search engines and how derivatives of these could be used for libraries' purposes. The goal of ranking is to provide the user with the best-suitable results on top of the results list. How can this goal be achieved with the library catalogue and also concerning the library's different collections and databases? The assumption is that ranking of such materials is a complex problem and is yet nowhere near solved. Libraries should focus on ranking to improve user experience.
  6. Lewandowski, D.: ¬The retrieval effectiveness of web search engines : considering results descriptions (2008) 0.00 
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    Abstract
    Purpose - The purpose of this paper is to compare five major web search engines (Google, Yahoo, MSN, Ask.com, and Seekport) for their retrieval effectiveness, taking into account not only the results, but also the results descriptions. Design/methodology/approach - The study uses real-life queries. Results are made anonymous and are randomized. Results are judged by the persons posing the original queries. Findings - The two major search engines, Google and Yahoo, perform best, and there are no significant differences between them. Google delivers significantly more relevant result descriptions than any other search engine. This could be one reason for users perceiving this engine as superior. Research limitations/implications - The study is based on a user model where the user takes into account a certain amount of results rather systematically. This may not be the case in real life. Practical implications - The paper implies that search engines should focus on relevant descriptions. Searchers are advised to use other search engines in addition to Google. Originality/value - This is the first major study comparing results and descriptions systematically and proposes new retrieval measures to take into account results descriptions.
    Source
    Journal of documentation. 64(2008) no.6, S.915-937
  7. Lewandowski, D.: Mit welchen Kennzahlen lässt sich die Qualität von Suchmaschinen messen? (2007) 0.00 
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    Abstract
    Suchmaschinen bilden den bedeutendsten Zugang zu den im World Wide Web verfügbaren Informationen und haben andere Zugänge zu diesem Informationsbestand (wie etwa Internetverzeichnisse) weitgehend verdrängt. Der Suchmaschinenmarkt ist stark konzentriert; nur wenige Anbieter mit eigener Technologie bieten selbst Endnutzerlösungen an und lizenzieren ihre Technologie an die bekannten Web-Portale wie AOL oder T-Online. Die im vorliegenden Kapitel dargestellten Kennzahlen zur Messung der Qualität von Suchmaschinen basieren einerseits auf Erkenntnissen über den State of the Art der Suchmaschinentechnologie, andererseits stehen sie im Kontext eines umfassenderen Modells der Qualitätsmessung für Web-Suchmaschinen. Die besondere Bedeutung von Erkenntnissen über die Qualität der bestehenden Suchmaschinen ergibt sich einerseits aus ihrer Bedeutung für die Weiterentwicklung der Suchmaschinentechnologie. Qualitätsuntersuchungen geben Hinweise auf die Schwachstellen der Suchmaschinen im Allgemeinen und die ihrer Ranking-Algorithmen im Besonderen. Letztere sind als zentral für die Ergebnisqualität anzusehen und bilden den >Kern< der technologischen Leistungsfähigkeit einer jeden Suchmaschine.
    Source
    Macht der Suchmaschinen: The Power of Search Engines. Hrsg.: Machill, M. u. M. Beiler
  8. Lewandowski, D.: Web Information Retrieval : Technologien zur Informationssuche im Internet (2005) 0.00 
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    Footnote
    Rez. in: Information - Wissenschaft und Praxis. 56(2005) H.7, S.393-394 (J. Griesbaum): "... , das Buch wird seinem Titel und dem formulierten Anspruch sehr gut gerecht. Die 248 Seiten umfängliche Publikation leistet eine umfassende und, für den deutschsprachigen Raum, einzigartige State-of-the-Art-Analyse der Verfahren und auch der Defizite von Suchmaschinen im Internet. Dabei beschränkt sich Lewandowski nicht auf eine technikzentrierte Beschreibung aktueller Retrievalansätze, sondern akzentuiert ebenso deutlich auch die Problemfelder bei der Nutzung von Suchmaschinen. Dieser nutzerzentrierte Ansatz kommt vor allem im konzeptionellen Teil der Arbeit zum Tragen, der das Ziel verfolgt, Suchmaschinennutzern verbesserte Rechercheoptionen zu verschaffen. Angesichts der nur in geringem Maße vorhandenen Recherchekenntnisse der Nutzer liegt die Herausforderung vor allem darin, solche verbesserten Recherchemöglichkeiten derart auszugestalten, dass sie sich in realen Suchkontexten auch tatsächlich auswirken und nicht etwa wie die meist als "Erweitere Suche" bezeichneten Anfragemasken ein kaum beachtetes Dasein fristen. Der Verfasser konzipiert in diesem wichtigen Forschungsfeld neue Ansätze, um die Oualität des Information Retrievals zu verbessern. ... "

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