cs276ainformationretrieval

cs276ainformationretrieval内容摘要：

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。