ISR10 The Indexing Function chapter Joseph John Rocchio Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. 2-18 be devised to implement the optimization 0£ the index images 0£ particular documents, in accordance with in£ormation obtained by subjective evaluation 0£ a user population will require a large sample 0£ experimental evidence such as can only be obtained in an operational system environment. The £ollowing chapter, however, o££ers experimental evidence that similar techniques are use£ul £or search request optimization.. I