cs276ainformationretrieval(編輯修改稿)
2024-11-29 17:52 本頁面
【文章內(nèi)容簡介】 nt Gear From Satellite Plan ? 3. , 04/04/90, Science Panel Backs NASA Satellite Plan, But Urges Launches of Smaller Probes ? 4. , 09/09/91, A NASA Satellite Project Acplishes Incredible Feat: Staying Within Budget ? 5. , 07/24/90, Scientist Who Exposed Global Warming Proposes Satellites for Climate Research ? 6. , 08/22/90, Report Provides Support for the Critics Of Using Big Satellites to Study Climate ? 7. , 04/13/87, Arianespace Receives Satellite Launch Pact From Telesat Canada ? + 8. , 12/02/87, Telemunications Tale of Two Companies Note: want high recall Relevance Feedback Example: Expanded Query ? new space ? satellite application ? nasa eos ? launch aster ? instrument arianespace ? bundespost ss ? rocket scientist ? broadcast earth ? oil measure Top 8 Results After Relevance Feedback ? + 1. , 07/09/91, NASA Scratches Environment Gear From Satellite Plan ? + 2. , 08/13/91, NASA Hasn39。t Scrapped Imaging Spectrometer ? 3. , 08/07/89, When the Pentagon Launches a Secret Satellite, Space Sleuths Do Some Spy Work of Their Own ? 4. , 07/31/89, NASA Uses 39。Warm? Superconductors For Fast Circuit ? + 5. , 07/09/91, Soviets May Adapt Parts of SS20 Missile For Commercial Use ? 6. , 07/12/88, Gaping Gap: Pentagon Lags in Race To Match the Soviets In Rocket Launchers ? 7. , 06/14/90, Rescue of Satellite By Space Agency To Cost $90 Million ? + 8. , 12/02/87, Telemunications Tale of Two Companies Evaluation of relevance feedback strategies ? Use q0 and pute precision and recall graph ? Use qm and pute precision recall graph ? Use all documents in the collection ? Spectacular improvements, but … it?s cheating! ? Partly due to known relevant documents ranked higher ? Must evaluate with respect to documents not seen by user ? Use documents in residual collection (set of documents minus those assessed relevant) ? Measures usually lower than for original query ? More realistic evaluation ? Relative performance can be validly pared ? Empirically, one round of relevance feedback is often very useful. Two rounds is sometimes marginally useful. Relevance Feedback on the Web ? Some search engines offer a similar/related pages feature (trivial form of relevance feedback) ? Google (linkbased) ? Altavista ? Stanford web ? But some don?t because it?s hard to explain to average user: ? Alltheweb ? msn ? Yahoo ? Excite initially had true relevance feedback, but abandoned it due to lack of use. α/β/γ ?? Other Uses of Relevance Feedback ? Following a changing information need ? Maintaining an information filter (., for a news feed) ? Active learning [Deciding which examples it is most useful to know
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