Diese Datenbank enthält über 40.000 Dokumente zu Themen aus den Bereichen Formalerschließung – Inhaltserschließung – Information Retrieval.
© 2015 W. Gödert, TH Köln, Institut für Informationswissenschaft / Powered by litecat, BIS Oldenburg (Stand: 28. April 2022)
21Wolfram, D. ; Zhang, J.: ¬An investigation of the influence of indexing exhaustivity and term distributions on a document space.
In: Journal of the American Society for Information Science and Technology. 53(2002) no.11, S.944-952.
Abstract: Wolfram and Zhang are interested in the effect of different indexing exhaustivity, by which they mean the number of terms chosen, and of different index term distributions and different term weighting methods on the resulting document cluster organization. The Distance Angle Retrieval Environment, DARE, which provides a two dimensional display of retrieved documents was used to represent the document clusters based upon a document's distance from the searcher's main interest, and on the angle formed by the document, a point representing a minor interest, and the point representing the main interest. If the centroid and the origin of the document space are assigned as major and minor points the average distance between documents and the centroid can be measured providing an indication of cluster organization. in the form of a size normalized similarity measure. Using 500 records from NTIS and nine models created by intersecting low, observed, and high exhaustivity levels (based upon a negative binomial distribution) with shallow, observed, and steep term distributions (based upon a Zipf distribution) simulation runs were preformed using inverse document frequency, inter-document term frequency, and inverse document frequency based upon both inter and intra-document frequencies. Low exhaustivity and shallow distributions result in a more dense document space and less effective retrieval. High exhaustivity and steeper distributions result in a more diffuse space.
23Spink, A. ; Wolfram, D. ; Jansen, B.J. ; Saracevic, T.: Searching the Web : the public and their queries.
In: Journal of the American Society for Information Science and technology. 52(2001) no.3, S.226-234.
Abstract: In previous articles, we reported the state of Web searching in 1997 (Jansen, Spink, & Saracevic, 2000) and in 1999 (Spink, Wolfram, Jansen, & Saracevic, 2001). Such snapshot studies and statistics on Web use appear regularly (OCLC, 1999), but provide little information about Web searching trends. In this article, we compare and contrast results from our two previous studies of Excite queries' data sets, each containing over 1 million queries submitted by over 200,000 Excite users collected on 16 September 1997 and 20 December 1999. We examine how public Web searching changing during that 2-year time period. As Table 1 shows, the overall structure of Web queries in some areas did not change, while in others we see change from 1997 to 1999. Our comparison shows how Web searching changed incrementally and also dramatically. We see some moves toward greater simplicity, including shorter queries (i.e., fewer terms) and shorter sessions (i.e., fewer queries per user), with little modification (addition or deletion) of terms in subsequent queries. The trend toward shorter queries suggests that Web information content should target specific terms in order to reach Web users. Another trend was to view fewer pages of results per query. Most Excite users examined only one page of results per query, since an Excite results page contains ten ranked Web sites. Were users satisfied with the results and did not need to view more pages? It appears that the public continues to have a low tolerance of wading through retrieved sites. This decline in interactivity levels is a disturbing finding for the future of Web searching. Queries that included Boolean operators were in the minority, but the percentage increased between the two time periods. Most Boolean use involved the AND operator with many mistakes. The use of relevance feedback almost doubled from 1997 to 1999, but overall use was still small. An unusually large number of terms were used with low frequency, such as personal names, spelling errors, non-English words, and Web-specific terms, such as URLs. Web query vocabulary contains more words than found in large English texts in general. The public language of Web queries has its own and unique characteristics. How did Web searching topics change from 1997 to 1999? We classified a random sample of 2,414 queries from 1997 and 2,539 queries from 1999 into 11 categories (Table 2). From 1997 to 1999, Web searching shifted from entertainment, recreation and sex, and pornography, preferences to e-commerce-related topics under commerce, travel, employment, and economy. This shift coincided with changes in information distribution on the publicly indexed Web.
Themenfeld: Internet ; Benutzerstudien ; Suchmaschinen
24Zhang, J. ; Wolfram, D.: Visualization of term discrimination analysis.
In: Journal of the American Society for Information Science and technology. 52(2001) no.8, S.615-627.
Abstract: Zang and Wolfram compute the discrimination value for terms as the difference between the centroid value of all terms in the corpus and that value without the term in question, and suggest selection be made by comparing density changes with a visualization tool. The Distance Angle Retrieval Environment (DARE) visually projects a document or term space by presenting distance similarity on the X axis and angular similarity on the Y axis. Thus a document icon appearing close to the X axis would be relevant to reference points in terms of a distance similarity measure, while those close to the Y axis are relevant to reference points in terms of an angle based measure. Using 450 Associated Press news reports indexed by 44 distinct terms, the removal of the term ``Yeltsin'' causes the cluster to fall on the Y axis indicating a good discriminator. For an angular measure, cosine say, movement along the X axis to the left will signal good discrimination, as movement to the right will signal poor discrimination. A term density space could also be used. Most terms are shown to be indifferent discriminators. Different measures result in different choices as good and poor discriminators, as does the use of a term space rather than a document space. The visualization approach is clearly feasible, and provides some additional insights not found in the computation of a discrimination value.
25Ross, N.C.M. ; Wolfram, D.: End user searching on the Internet : an analysis of term pair topics submitted to the Excite search engine.
In: Journal of the American Society for Information Science. 51(2000) no.10, S.949-958.
Abstract: Queries submitted to the Excite search engine were analyzed for subject content based on the cooccurrence of terms within multiterm queries. More than 1000 of the most frequently cooccurring term pairs were categorized into one or more of 30 developed subject areas. Subject area frequencies and their cooccurrences with one another were tallied and analyzed using hierarchical cluster analysis and multidimensional scaling. The cluster analyses revealed several anticipated and a few unanticipated groupings of subjects, resulting in several well-defined high-level clusters of broad subject areas. Multidimensional scaling of subject cooccurrences revealed similar relationships among the different subject categories. Applications that arise from a better understanding of the topics users search and their relationships are discussed
Themenfeld: Suchmaschinen ; Internet ; Benutzerstudien
27Wolfram, D. ; Dimitroff, A.: Preliminary findings on searcher performance and perceptions of performance in a hypertext bibliographic retrieval system.
In: Journal of the American Society for Information Science. 48(1997) no.12, S.1142-1145.
Abstract: Reports on research examining the relationship of searcher performance and perception of performance, particulary for hypertext-based onformation retrieval systems for bibliographic data. Employs a prototype hypertext bibliographic retrieval system called HyperLynx. Evaluates its use by 83 subjects at the School of Library and Information Science and the Golda Meir Library at the University of Wisconsin-Milwaukee, USA. Measures of system usgae indicate that there is no significant relationship between confidence and the number of record pages visited, although confident searchers searched for shorter time periods. The reality check measures shows that both novice and experienced searchers were over confident in their performance
Themenfeld: Hypertext ; Retrievalstudien
28Wolfram, D. ; Volz, A. ; Dimitroff, A.: ¬The effect of linkage structure on retrieval performance in a hypertext-based bibliographic retrieval system.
In: Information processing and management. 32(1996) no.5, S.529-541.
Abstract: Investigates how linkage environments in a hypertext based bibliographic retrieval system affect retrieval performance for novice and experienced searchers, 2 systems, 1 with inter record linkages to authors and descriptors and 1 that also included title and abstract keywords, were tested. No significant differences in retrieval performance and system usage were found for most search tests. The enhanced system did provide better performance where title and abstract keywords provided the most direct access to relevant records. The findings have implications for the design of bilbiographic information retrieval systems using hypertext linkages
Themenfeld: Retrievalstudien ; Hypertext
29Wolfram, D.: Inter-record linkage structure in a hypertext bibliographic retrieval system.
In: Journal of the American Society for Information Science. 47(1996) no.10, S.765-774.
Abstract: Explores inter record linkage relationships of a bibliographic hypertext system through the use of descriptor term co-occurrences. Using term distribution and term exhaustivity data for an existing system, develops 3 models of term co-occurrence and tests against the observed data. The developed models do not adequately model the observed co-occurrence patterns for select parts of the distribution using chi-square values. With knowledge of the structure of such a hypertext system, an appropriate model may be constructed and used as the basis for studying systems design of inter-record linkages and system navigation by users in such a hypertext system
30Dimitroff, A. ; Wolfram, D. ; Volz, A.: Affective response and retrieval performance : analysis of contributing factors.
In: Library and information science research. 18(1996) no.2, S.121-132.
Abstract: Describes a study which investigated the affective response of 83 subjects to 2 versions of a hypertext-based bibliographic retrieval system. The objective of the study was to determine if subjects preferred searching a hypertext information retrieval (IR) system via traditional bibliographic links or via an enhanced set of linkages between structured records. The study also examined the utility of using factor analysis to explore subjects' affective responses to searching the 2 hypertext-based IR systems; explored the effect of experience on search outcome; and compared the effect of different types of linkages within the hypertext system. Findings reveal a complex relationship between system and user that is sometimes contradictory. Searchers found the systems to be usable or unusable in different ways indicating that further researchg is needed to isolate to specific features that searchers find frustrating or not in searching structured records via a hypertext-based IR system
Themenfeld: Hypertext ; Retrievalstudien
31Dimitroff, A. ; Wolfram, D.: Searcher response in a hypertext-based bibliographic information retrieval system.
In: Journal of the American Society for Information Science. 46(1995) no.1, S.22-29.
Abstract: This article examines searcher behavior and affective response to a hypertext-based bibliographic information retrieval system called HyperLynx for searchers with different search skills and backgrounds. Search times and number of nodes visited were recorded for five specified search queries, and views of the system were recorded for each searcher. No significant differences were found in search times or user satisfaction with the system, indicating that a hypertext-based approach to bibliographic retrieval could be appropriate for a variety of searcher experience levels
32Wittig, C. ; Wolfram, D.: ¬A survey of networking education in North American library schools.
In: Library trends. 42(1994) no.4, S.626-637.
Abstract: Reports results of a survey of US library schools to investigate the adoption, impact, and role of networking concepts and resources, such as the Internet, in the library and information science curriculum. Findings indicate that, to a large degree, educators have kept up with recent trends and tools in networking in a variety of courses. There was overwhelming consensus on the importance of networked information resources and access tools but less agreement on their places in the library and information science curriculum
Themenfeld: Internet ; Ausbildung
33Minitroff, A. ; Wolfram, D.: Design issues in a hypertext-based information system for bibliographic retrieval.
In: Integrating technologies - converging professions: proceedings of the 56th Annual Meeting of the American Society for Information Science, Columbus, OH, 24-28 October 1993. Ed.: S. Bonzi. Medford, NJ : Learned Information, 1993. S.191-198.
Abstract: Examnies several feasibility issues and initial design considerations for a hypertext system for structured bibliographic retrieval. HyperLynx was developed using Asymmetric Toolbox. By combining searchable term indexes and inter-record linkages between common authors and descriptors, a flexible search environment is established conductive to browsing