ISR10 Search Request Formulation 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. M [OCRerr];` 3-1 CHAPTER 3 SEAF[OCRerr]CR [OCRerr] FO[OCRerr]LA[OCRerr]IO[OCRerr] 1. Introduction The dialogue initiated by user-generate&' Iriputs to a document retrieval system is a dynamic communication process that needs to be optimized if the system is to provide effective service. A general block diagram of a retrieval system delineating possible user-system interfaces is shown in Figure 3.1. It will be assumed that the operational environment of the system, allows for real-time int.eraction between the user and the system, and that this facility can be exploited in the implementation of the overall reque'st formulation process. The block labeled "[OCRerr]uery formalizer" may be interpreted as an initial preprocessing stage designed to buffer the user from the internal structure of the system. Simple processes such as error detection (`spelling, etc.), as well as[OCRerr]more complex ones (vocabulary aids in the form of suggested synor[OCRerr]yms and term relations), may be incorporated here.1'2 The present section, however, deals with the impleme'ntation of the block labeled `1query modifier". In particular, it is assumed that the system allows for iterative searching, and is capable' of automatically modifying the * ` user's original query on the basis of' the `results of previous iterations and of the user's evaluation of these results. To this end the concept of search' request optimality is introduced, `and the