ISR11 Operating Instructions for the SMART Text Processing and Document Retrieval System chapter M. E. Lesk Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. ii-i6 3.5. Vector Formation The final vector is formed by c[OCRerr]iibinjng all the concepts introduced from all sources with appropriate weights. The weighting parameters are nun[OCRerr]bers which are zero or greater (and may be greater than 1), indicating the weight associated with each unit occurrence of the given concept in the specified class. The weighting parameters are: STE[OCRerr][OCRerr] x x is the weight associated with word stem concepts. It should be a FORTRAN floating point number (e.g. 1.0, not 1); STATWT x x is the weight for statistical phrases STATPR rniist have been specified when lookup was done; otherwise this c[OCRerr]imiand is ignored. If STATPR was specified, phrases may be ignored by giving STATWT 0.0; x is the weight associated with syntactic phrases; x is the weight associated with concept-concept expansion concepts SYNWT x COCOWT x The hierarchical weighting specifications are used to select the method of hierarchical expansion. Any inmber of expansions with arbitrary weights may be performed simultaneously. There are four weighting para- meters, one for each possible mode of expansion. If the weight for a possible expansion mode is zero, that expansion is not performed. If the weight for a possible expansion is not zero, the expansion is performed and the concepts derived from it are given the indicated weight. ROOTWT x specifies the weight for expansion by parents; BRANWT x specifies the weight for expansion by brothers; L[OCRerr]A1WT x specifies the weight associated with expansion by sons; CROSWT x specifies the weight associated with expansion by cross- references.