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Probabilistic Question Answering On The Web - Clair
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Probabilistic Question Answering on the Web Dragomir Radev, Weiguo Fan, Hong Qi, Harris Wu, Amardeep Grewal The University of Michigan Ann Arbor, MI, 48105 USA ABSTRACT ! " # $ % & # '(()* # +, )-. / & 0$) Categories and Subject Descriptors 12 3 4" 5 6 7+ 3 4" 0 - 6 7+/ 3 4" 5 8 General Terms 9 7 - ( Keywords 1. INTRODUCTION TO WEB-BASED Q&A 9 : ;90 - < = >? < Copyright is held by the author/owner(s). , May 7–11, 2002, Honolulu, Hawaii, USA. ACM 1-58113-449-5/02/0005. 9 >? <' &) &) * 97 '@= :*? # # A 9 'A9* $ ( ( ) # '(()* $ B 5 0$) ' < ?* A9 () 9 # C 5 3D4 $ 3+4 9 # C : 5 $ ! : < ? < ? ! A9 ' * 1 ; # < 9 >? # ' * ! "# $" $ %#&&& '% ( ) * + , # "# - "" &#& & & "EE # "EE "EE "/2,,E "EE $ # $ ! : # 9 9 ; D 9 # A9 (() '( ( ) # * # (() # # ' * ' * # 0 9 9 0 F +,,D 2. RELATED WORK 0 9) 3G4 ! A9 1 5$ $ 9 # 9 5B)9H 324 # 5B)9H 9 A9 ( " )-. AI9 3J4 6 # 2.1 Related work from TREC )-. 3J4 0 )-. +K 3L M4 # # # # 3/4 AI9 $) ( 9 ! # # # ( # ! 9 3+4 ! ; ! ! 9 K ! ! & # .# 3N4 # O $7; # 9 # # 9 % % # 3D,4 ; ( P ! ; )-. AI9 3J4 2.2 Related work on the Web )-. % A 9 1 ! )-. Q % AI9 8 & 3DD4 # % 9 3D+4 ! 9 3DG4 K ! ! 9 # $ 9 # 3D24 9 DJ ! -5 % ! 9 AI9 3D4 0 )-. ; $ # ! # ! " 0 3D+ M4 O $7; ' * & % 3D4 9 5 E $ 5 D,, # '& -O 7 0 ( . +,,+* # $ ! # 0 # 9 % # 3. A PROBABILISTIC APPROACH TO PHRASE RERANKING 3.1 The general architecture of our system & " 8 3D24 $ : 8 " O 8 # ' * ' * 8 8 ' * # 8 # 3.2 Evaluation metric 9 # ' * # ' * " R D 'D* ' * ; D, " S S R M+J )7) ! $ # ' * )7) )-. % )-. # ! B )7) )-. # ! 9 )-. P % ' * # ' P !* < ? 3J4 $ )-. / N D, $0 3J4 D,,, E B +,, )-./ 5 % ! ! )-. 3.3 Manual vs. automatic evaluation consistency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