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  • × author_ss:"Thelwall, M."
  • × theme_ss:"Suchmaschinen"
  • × type_ss:"a"
  1. Thelwall, M.: Directing students to new information types : a new role for Google in literature searches? (2005) 0.01
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    Date
    3. 6.2007 16:37:29
    Series
    Internet reference services quarterly. 10(2005) nos.3/4
  2. Thelwall, M.: Assessing web search engines : a webometric approach (2011) 0.00
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    Abstract
    Information Retrieval (IR) research typically evaluates search systems in terms of the standard precision, recall and F-measures to weight the relative importance of precision and recall (e.g. van Rijsbergen, 1979). All of these assess the extent to which the system returns good matches for a query. In contrast, webometric measures are designed specifically for web search engines and are designed to monitor changes in results over time and various aspects of the internal logic of the way in which search engine select the results to be returned. This chapter introduces a range of webometric measurements and illustrates them with case studies of Google, Bing and Yahoo! This is a very fertile area for simple and complex new investigations into search engine results.
    Source
    Innovations in information retrieval: perspectives for theory and practice. Eds.: A. Foster, u. P. Rafferty
  3. Thelwall, M.: Can Google's PageRank be used to find the most important academic Web pages? (2003) 0.00
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    Abstract
    Google's PageRank is an influential algorithm that uses a model of Web use that is dominated by its link structure in order to rank pages by their estimated value to the Web community. This paper reports on the outcome of applying the algorithm to the Web sites of three national university systems in order to test whether it is capable of identifying the most important Web pages. The results are also compared with simple inlink counts. It was discovered that the highest inlinked pages do not always have the highest PageRank, indicating that the two metrics are genuinely different, even for the top pages. More significantly, however, internal links dominated external links for the high ranks in either method and superficial reasons accounted for high scores in both cases. It is concluded that PageRank is not useful for identifying the top pages in a site and that it must be combined with a powerful text matching techniques in order to get the quality of information retrieval results provided by Google.
  4. Thelwall, M.; Vaughan, L.: New versions of PageRank employing alternative Web document models (2004) 0.00
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    Abstract
    Introduces several new versions of PageRank (the link based Web page ranking algorithm), based on an information science perspective on the concept of the Web document. Although the Web page is the typical indivisible unit of information in search engine results and most Web information retrieval algorithms, other research has suggested that aggregating pages based on directories and domains gives promising alternatives, particularly when Web links are the object of study. The new algorithms introduced based on these alternatives were used to rank four sets of Web pages. The ranking results were compared with human subjects' rankings. The results of the tests were somewhat inconclusive: the new approach worked well for the set that includes pages from different Web sites; however, it does not work well in ranking pages that are from the same site. It seems that the new algorithms may be effective for some tasks but not for others, especially when only low numbers of links are involved or the pages to be ranked are from the same site or directory.
  5. Thelwall, M.; Binns, R.; Harries, G.; Page-Kennedy, T.; Price, L.; Wilkinson, D.: Custom interfaces for advanced queries in search engines (2001) 0.00
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    Abstract
    Those seeking information from the Internet often start from a search engine, using either its organised directory structure or its text query facility. In response to the difficulty in identifying the most relevant pages for some information needs, many search engines offer Boolean text matching and some, including Google, AltaVista and HotBot, offer the facility to integrate additional information into a more advanced request. Amongst web users, however, it is known that the employment of complex enquiries is far from universal, with very short queries being the norm. It is demonstrated that the gap between the provision of advanced search facilities and their use can be bridged, for specific information needs, by the construction of a simple interface in the form of a website that automatically formulates the necessary requests. It is argued that this kind of resource, perhaps employing additional knowledge domain specific information, is one that could be useful for websites or portals of common interest groups. The approach is illustrated by a website that enables a user to search the individual websites of university level institutions in European Union associated countries.
  6. Vaughan, L.; Thelwall, M.: Search engine coverage bias : evidence and possible causes (2004) 0.00
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    Date
    14. 8.2004 10:30:29