Next: 15.1 Some Background on Topics in Information Retrival �$B9)F#�(B �$BBs�(B taku-ku@is.aist-nara.ac.jp �$B<+A38@8l=hM}3X9V:B�(B M1 August 3, 1999 15.1 Some Background on Information Retrieval 15.1.1 Common design features of IR systems 15.1.2 Evaluation measuers 15.1.3 The probability ranking principle(PRP) 15.2 The Vector Space Model 15.2.1 Vector similarity 15.2.2 Term weighting 15.3 Term D