Search (458 results, page 1 of 23)

  • × theme_ss:"Retrievalstudien"
  1. Gauch, S.; Wang, J.: Corpus analysis for TREC 5 query expansion (1997) 0.44
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    Source
    The Fifth Text Retrieval Conference (TREC-5). Ed.: E.M. Voorhees u. D.K. Harman
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  2. Smeaton, A.F.; Kelledy, L.; O'Donnell, R.: TREC-4 experiments at Dublin City University : thresholding posting lists, query expansion with WordNet and POS tagging of Spanish (1996) 0.35
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    Source
    The Fourth Text Retrieval Conference (TREC-4). Ed.: K. Harman
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  3. Ekmekcioglu, F.C.; Robertson, A.M.; Willett, P.: Effectiveness of query expansion in ranked-output document retrieval systems (1992) 0.30
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    Abstract
    Reports an evaluation of 3 methods for the expansion of natural language queries in ranked output retrieval systems. The methods are based on term co-occurrence data, on Soundex codes, and on a string similarity measure. Searches for 110 queries in a data base of 26.280 titles and abstracts suggest that there is no significant difference in retrieval effectiveness between any of these methods and unexpanded searches
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  4. Robertson, S.E.; Walker, S.; Hancock-Beaulieu, M.M.: Large test collection experiments of an operational, interactive system : OKAPI at TREC (1995) 0.25
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    Abstract
    The Okapi system has been used in a series of experiments on the TREC collections, investiganting probabilistic methods, relevance feedback, and query expansion, and interaction issues. Some new probabilistic models have been developed, resulting in simple weigthing functions that take account of document length and within document and within query term frequency. All have been shown to be beneficial when based on large quantities of relevance data as in the routing task. Interaction issues are much more difficult to evaluate in the TREC framework, and no benefits have yet been demonstrated from feedback based on small numbers of 'relevant' items identified by intermediary searchers
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  5. Buckley, C.; Allan, J.; Salton, G.: Automatic routing and retrieval using Smart : TREC-2 (1995) 0.22
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    Abstract
    The Smart information retrieval project emphazises completely automatic approaches to the understanding and retrieval of large quantities of text. The work in the TREC-2 environment continues, performing both routing and ad hoc experiments. The ad hoc work extends investigations into combining global similarities, giving an overall indication of how a document matches a query, with local similarities identifying a smaller part of the document that matches the query. The performance of ad hoc runs is good, but it is clear that full advantage of the available local information is not been taken advantage of. The routing experiments use conventional relevance feedback approaches to routing, but with a much greater degree of query expansion than was previously done. The length of a query vector is increased by a factor of 5 to 10 by adding terms found in previously seen relevant documents. This approach improves effectiveness by 30-40% over the original query
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  6. Kwok, K.L.: ¬A network approach to probabilistic information retrieval (1995) 0.22
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    Abstract
    Shows how probabilistic information retrieval based on document components may be implemented as a feedforward (feedbackward) artificial neural network. The network supports adaptation of connection weights as well as the growing of new edges between queries and terms based on user relevance feedback data for training, and it reflects query modification and expansion in information retrieval. A learning rule is applied that can also be viewed as supporting sequential learning using a harmonic sequence learning rate. Experimental results with 4 standard small collections and a large Wall Street Journal collection show that small query expansion levels of about 30 terms can achieve most of the gains at the low-recall high-precision region, while larger expansion levels continue to provide gains at the high-recall low-precision region of a precision recall curve
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  7. Colace, F.; Santo, M. de; Greco, L.; Napoletano, P.: Improving relevance feedback-based query expansion by the use of a weighted word pairs approach (2015) 0.22
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    Abstract
    In this article, the use of a new term extraction method for query expansion (QE) in text retrieval is investigated. The new method expands the initial query with a structured representation made of weighted word pairs (WWP) extracted from a set of training documents (relevance feedback). Standard text retrieval systems can handle a WWP structure through custom Boolean weighted models. We experimented with both the explicit and pseudorelevance feedback schemas and compared the proposed term extraction method with others in the literature, such as KLD and RM3. Evaluations have been conducted on a number of test collections (Text REtrivel Conference [TREC]-6, -7, -8, -9, and -10). Results demonstrated that the QE method based on this new structure outperforms the baseline.
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  8. Chen, H.; Martinez, J.; Kirchhoff, A.; Ng, T.D.; Schatz, B.R.: Alleviating search uncertainty through concept associations : automatic indexing, co-occurence analysis, and parallel computing (1998) 0.21
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    Abstract
    In this article, we report research on an algorithmic approach to alleviating search uncertainty in a large information space. Grounded on object filtering, automatic indexing, and co-occurence analysis, we performed a large-scale experiment using a parallel supercomputer (SGI Power Challenge) to analyze 400.000+ abstracts in an INSPEC computer engineering collection. Two system-generated thesauri, one based on a combined object filtering and automatic indexing method, and the other based on automatic indexing only, were compaed with the human-generated INSPEC subject thesaurus. Our user evaluation revealed that the system-generated thesauri were better than the INSPEC thesaurus in 'concept recall', but in 'concept precision' the 3 thesauri were comparable. Our analysis also revealed that the terms suggested by the 3 thesauri were complementary and could be used to significantly increase 'variety' in search terms the thereby reduce search uncertainty
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  9. Tseng, Y.-H.: Solving vocabulary problems with interactive query expansion (1998) 0.19
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    Abstract
    One of the major causes of search failures in information retrieval systems is vocabulary mismatch. Presents a solution to the vocabulary problem through 2 strategies known as term suggestion (TS) and term relevance feedback (TRF). In TS, collection specific terms are extracted from the text collection. These terms and their frequencies constitute the keyword database for suggesting terms in response to users' queries. One effect of this term suggestion is that it functions as a dynamic directory if the query is a general term that contains broad meaning. In term relevance feedback, terms extracted from the top ranked documents retrieved from the previous query are shown to users for relevance feedback. In the experiment, interactive TS provides very high precision rates while achieving similar recall rates as n-gram matching. Local TRF achieves improvement in both precision and recall rate in a full text news database and degrades slightly in recall rate in bibliographic databases due to the very limited source of information for feedback. In terms of Rijsbergen's combined measure of recall and precision, both TS and TRF achieve better performance than n-gram matching, which implies that the greater improvement in precision rate compensates the slight degradation in recall rate for TS and TRF
    Footnote
    In Chinesisch
    Theme
    Semantisches Umfeld in Indexierung u. Retrieval
  10. Scherer, B.: Automatische Indexierung und ihre Anwendung im DFG-Projekt "Gemeinsames Portal für Bibliotheken, Archive und Museen (BAM)" (2003) 0.11
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    Abstract
    Automatische Indexierung verzeichnet schon seit einigen Jahren aufgrund steigender Informationsflut ein wachsendes Interesse. Allerdings gibt es immer noch Vorbehalte gegenüber der intellektuellen Indexierung in Bezug auf Qualität und größerem Aufwand der Systemimplementierung bzw. -pflege. Neuere Entwicklungen aus dem Bereich des Wissensmanagements, wie beispielsweise Verfahren aus der Künstlichen Intelligenz, der Informationsextraktion, dem Text Mining bzw. der automatischen Klassifikation sollen die automatische Indexierung aufwerten und verbessern. Damit soll eine intelligentere und mehr inhaltsbasierte Erschließung geleistet werden. In dieser Masterarbeit wird außerhalb der Darstellung von Grundlagen und Verfahren der automatischen Indexierung sowie neueren Entwicklungen auch Möglichkeiten der Evaluation dargestellt. Die mögliche Anwendung der automatischen Indexierung im DFG-ProjektGemeinsames Portal für Bibliotheken, Archive und Museen (BAM)" bilden den Schwerpunkt der Arbeit. Im Portal steht die bibliothekarische Erschließung von Texten im Vordergrund. In einem umfangreichen Test werden drei deutsche, linguistische Systeme mit statistischen Verfahren kombiniert (die aber teilweise im System bereits integriert ist) und evaluiert, allerdings nur auf der Basis der ausgegebenen Indexate. Abschließend kann festgestellt werden, dass die Ergebnisse und damit die Qualität (bezogen auf die Indexate) von intellektueller und automatischer Indexierung noch signifikant unterschiedlich sind. Die Gründe liegen in noch zu lösenden semantischen Problemen bzw, in der Obereinstimmung mit Worten aus einem Thesaurus, die von einem automatischen Indexierungssystem nicht immer nachvollzogen werden kann. Eine Inhaltsanreicherung mit den Indexaten zum Vorteil beim Retrieval kann, je nach System oder auch über die Einbindung durch einen Thesaurus, erreicht werden.
    Footnote
    Masterarbeit im Studiengang Information Engineering zur Erlagung des Grades eines Master of Science in Information science,
  11. Binder, G.; Stahl, M.; Faulborn, L.: Vergleichsuntersuchung MESSENGER-FULCRUM (2000) 0.09
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    Abstract
    In einem Benutzertest, der im Rahmen der Projektes GIRT stattfand, wurde die Leistungsfähigkeit zweier Retrievalsprachen für die Datenbankrecherche überprüft. Die Ergebnisse werden in diesem Bericht dargestellt: Das System FULCRUM beruht auf automatischer Indexierung und liefert ein nach statistischer Relevanz sortiertes Suchergebnis. Die Standardfreitextsuche des Systems MESSENGER wurde um die intellektuell vom IZ vergebenen Deskriptoren ergänzt. Die Ergebnisse zeigen, dass in FULCRUM das Boole'sche Exakt-Match-Retrieval dem Verktos-Space-Modell (Best-Match-Verfahren) von den Versuchspersonen vorgezogen wurde. Die in MESSENGER realisierte Mischform aus intellektueller und automatischer Indexierung erwies sich gegenüber dem quantitativ-statistischen Ansatz beim Recall als überlegen
  12. ¬The Fifth Text Retrieval Conference (TREC-5) (1997) 0.09
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    Abstract
    Proceedings of the 5th TREC-confrerence held in Gaithersburgh, Maryland, Nov 20-22, 1996. Aim of the conference was discussion on retrieval techniques for large test collections. Different research groups used different techniques, such as automated thesauri, term weighting, natural language techniques, relevance feedback and advanced pattern matching, for information retrieval from the same large database. This procedure makes it possible to compare the results. The proceedings include papers, tables of the system results, and brief system descriptions including timing and storage information
    Editor
    Voorhees, E.M. u. D.K. Harman
  13. ¬The Eleventh Text Retrieval Conference, TREC 2002 (2003) 0.09
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    Abstract
    Proceedings of the llth TREC-conference held in Gaithersburg, Maryland (USA), November 19-22, 2002. Aim of the conference was discussion an retrieval and related information-seeking tasks for large test collection. 93 research groups used different techniques, for information retrieval from the same large database. This procedure makes it possible to compare the results. The tasks are: Cross-language searching, filtering, interactive searching, searching for novelty, question answering, searching for video shots, and Web searching.
    Editor
    Voorhees, E.M. u. D.K. Harman
  14. Womser-Hacker, C.: Theorie des Information Retrieval III : Evaluierung (2004) 0.07
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    Abstract
    Information-Retrieval-Systeme wurden bereits sehr früh aus einer bewertenden Perspektive betrachtet. Jede neu entwickelte Komponente sollte effektivitätssteigernd für das gesamte System wirken und musste ihre Funktionalität unter Beweis stellen oder den Vergleich zu existierenden Verfahren antreten (z.B. automatische Indexierung vs. manuelle Erschließung von Informationsobjekten). 1963 fanden die Cranfield-II-Experimente statt und begründeten die Evaluierungsprinzipien im Information Retrieval. Somit haben auch Bewertungsverfahren, -ansätze und -methoden bereits eine lange Tradition. Die von Sparck Jones eingebrachte Feststellung, dass die genauen Gründe für das Verhalten von Information-Retrieval-Systemen oft im Dunklen lägen, führte zu der Forderung nach einer exakten und expliziten Evaluierungsmethodologie und experimentellen Überprüfbarkeit. Als generelle Herangehensweise hat sich ein indirektes Verfahren zur Bewertung von InformationRetrieval-Systemen etabliert, bei welchem das System an sich als black box gesehen und nur der Retrievaloutput als Grundlage für die Bewertung herangezogen wird. In den Experimenten stand die Systemperspektive im Vordergrund, um zu einer bewertenden Aussage zu gelangen. Es wurde gemessen, wie gut die Systeme in der Lage sind, die an sie gestellten Anforderungen zu erfüllen, relevante Dokumente zu liefern und nicht-relevante zurückzuhalten. Durch die zunehmende Komplexität der Systeme sowie die immer stärkere Einbeziehung von Benutzern, die nicht über die Kompetenz und Professionalität von Informationsfachleuten verfügen, wurde es immer schwieriger, Einzeleigenschaften vom Gesamtsystem zu isolieren und experimentell zu bewerten. Erst im Zeitalter der Suchmaschinen ist man zu der Ansicht gelangt, dass den Benutzern der Systeme eine entscheidende Rolle bei der Bewertung zukommt. Die Verfahren der Qualitätsbewertung müssen - wie dieses Beispiel zeigt - ständig weiterentwickelt werden. Die Benutzermerkmale können heterogen sein und sich einer genauen Kenntnis entziehen, was eine vollständige Formalisierung bzw. Quantifizierung erschwert. Neueren Datums sind Studien, die sich auf interaktive Information-Retrieval-Systeme oder auf die Qualitätsbestimmung bestimmter Teilkomponenten spezialisiert haben wie z.B. die Erschließungsoder Visualisierungskomponente, die Gestaltung der Benutzungsschnittstelle aus softwareergonomischer Sicht oder auch die Multilingua-Fähigkeit.
    Source
    Grundlagen der praktischen Information und Dokumentation. 5., völlig neu gefaßte Ausgabe. 2 Bde. Hrsg. von R. Kuhlen, Th. Seeger u. D. Strauch. Begründet von Klaus Laisiepen, Ernst Lutterbeck, Karl-Heinrich Meyer-Uhlenried. Bd.1: Handbuch zur Einführung in die Informationswissenschaft und -praxis
  15. ¬The Second Text Retrieval Conference : TREC-2 (1995) 0.07
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    Abstract
    A special issue devoted to papers from the 2nd Text Retrieval Conference (TREC-2) held in Aug 93
    Content
    Enthält die Beiträge: HARMAN, D.: Overview of the Second Text Retrieval Conference (TREC-2); SPRACK JONES, K.: Reflections on TREC; BUCKLEY, C., J. ALLAN u. G. SALTON: Automatic routing and retrieval using SMART: TREC-2; CALLAN, J.P., W.B. CROFT u. J. BROGLIO: TREC and TIPSTER experiments with INQUERY; ROBERTSON, S.R., S. WALKER u. M.M. HANCOCK-BEAULIEU: Large test collection experiments on an operational, interactive system: OKAPI at TREC; ZOBEL, J., A. MOFFAT, R. WILKINSON u. R. SACKS-DAVIS: Efficient retrieval of partial documents; METTLER, M. u. F. NORDBY: TREC routing experiments with the TRW/Paracel Fast Data Finder; EVANS, D.A. u. R.G. LEFFERTS: CLARIT-TREC experiments; STRZALKOWSKI, T.: Natural language information retrieval; CAID, W.R., S.T. DUMAIS u. S.I. GALLANT: Learned vector-space models for document retrieval; BELKIN, N.J. P. KANTOR, E.A. FOX u. J.A. SHAW: Combining the evidence of multiple query representations for information retrieval
  16. Buckley, C.; Voorhees, E.M.: Retrieval system evaluation (2005) 0.07
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    Source
    TREC: experiment and evaluation in information retrieval. Ed.: E.M. Voorhees, u. D.K. Harman
  17. Gödert, W.; Liebig, M.: Maschinelle Indexierung auf dem Prüfstand : Ergebnisse eines Retrievaltests zum MILOS II Projekt (1997) 0.07
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    Abstract
    The test ran between Nov 95-Aug 96 in Cologne Fachhochschule fur Bibliothekswesen (College of Librarianship).The test basis was a database of 190,000 book titles published between 1990-95. MILOS II mechanized indexing methods proved helpful in avoiding or reducing numbers of unsatisfied/no result retrieval searches. Retrieval from mechanised indexing is 3 times more successful than from title keyword data. MILOS II also used a standardized semantic vocabulary. Mechanised indexing demands high quality software and output data
  18. Lepsky, K.; Siepmann, J.; Zimmermann, A.: Automatische Indexierung für Online-Kataloge : Ergebnisse eines Retrievaltests (1996) 0.07
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    Abstract
    Examines the effectiveness of automated indexing and presents the results of a study of information retrieval from a segment (40.000 items) of the ULB Düsseldorf database. The segment was selected randomly and all the documents included were indexed automatically. The search topics included 50 subject areas ranging from economic growth to alternative energy sources. While there were 876 relevant documents in the database segment for each of the 50 search topics, the recall ranged from 1 to 244 references, with the average being 17.52 documents per topic. Therefore it seems that, in the immediate future, automatic indexing should be used in combination with intellectual indexing
  19. Rapke, K.: Automatische Indexierung von Volltexten für die Gruner+Jahr Pressedatenbank (2001) 0.07
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    Abstract
    Retrieval Tests sind die anerkannteste Methode, um neue Verfahren der Inhaltserschließung gegenüber traditionellen Verfahren zu rechtfertigen. Im Rahmen einer Diplomarbeit wurden zwei grundsätzlich unterschiedliche Systeme der automatischen inhaltlichen Erschließung anhand der Pressedatenbank des Verlagshauses Gruner + Jahr (G+J) getestet und evaluiert. Untersucht wurde dabei natürlichsprachliches Retrieval im Vergleich zu Booleschem Retrieval. Bei den beiden Systemen handelt es sich zum einen um Autonomy von Autonomy Inc. und DocCat, das von IBM an die Datenbankstruktur der G+J Pressedatenbank angepasst wurde. Ersteres ist ein auf natürlichsprachlichem Retrieval basierendes, probabilistisches System. DocCat demgegenüber basiert auf Booleschem Retrieval und ist ein lernendes System, das auf Grund einer intellektuell erstellten Trainingsvorlage indexiert. Methodisch geht die Evaluation vom realen Anwendungskontext der Textdokumentation von G+J aus. Die Tests werden sowohl unter statistischen wie auch qualitativen Gesichtspunkten bewertet. Ein Ergebnis der Tests ist, dass DocCat einige Mängel gegenüber der intellektuellen Inhaltserschließung aufweist, die noch behoben werden müssen, während das natürlichsprachliche Retrieval von Autonomy in diesem Rahmen und für die speziellen Anforderungen der G+J Textdokumentation so nicht einsetzbar ist
  20. Harman, D.K.: ¬The TREC conferences (1995) 0.06
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    Footnote
    Wiederabgedruckt in: Readings in information retrieval. Ed.: K. Sparck Jones u. P. Willett. San Francisco: Morgan Kaufman 1997. S.247-256.
    Source
    Hypertext - Information Retrieval - Multimedia: HIM '95. Synergieeffekte elektronischer Informationssysteme. Hrsg.: R. Kuhlen u. M. Rittberger

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