Carnegie Mellon University - CS 1164103-IntroToSearch

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11-442 / 11-642: Search Engines Two Lecture Outline 50 © 2019, Jamie Callan A quick introduction to… • Ad-hoc retrieval • Information needs & queries • Document representation • Exa... ct match retrieval – Unranked Boolean – Ranked Boolean • Indexes – Inverted lists – Term dictionary • Document retrieval – TAAT – DAAT • Query operators Goal: Provide an overview of search (“the Big Picture”) • Later lectures explore these topics in greater detail 2 Page 2 Document Retrieval: Document-at-a-Time (DAAT) Query Evaluation Key idea • Compute a complete score for doci before proceeding to doci+1 The following example assumes an unranked Boolean model. • All scores are 1 • The same architecture can be used for ranked Boolean 51 © 2019, Jamie Callan Document Retrieval: Document-at-a-Time (DAAT) Query Evaluation Starting condition: • The query is #OR (a b c) 52 © 2019, Jamie Callan 3 Page 3 Document Retrieval: Document-at-a-Time (DAAT) Query Evaluation Starting condition: • The query is #OR (a b c) • Parse the query 53 © 2019, Jamie Callan abc OR Document Retrieval: Document-at-a-Time (DAAT) Query Evaluation Starting condition: • The query is #OR (a b c) • Parse the query • Retrieve the inverted list for each term [Show More]

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