公开(公告)号：CA1290061C

公开(公告)日：1991-10-01

申请号：CA552058

申请日：1987-11-17

Applicant: IBM

Inventor： LISLE RONALD J ,  MOSS EUAL A ,  RYDER JOHN H

IPC: G06F5/00 ,  G06F17/22 ,  H03M7/30 ,  H03M7/42

Abstract: RA986014 TEXT COMPRESSION AND EXPANSION METHOD AND APPARATUS A text compression method and apparatus are disclosed that enable overall compression ratios of more than six or eight to one for normal language test. Plural multiple-word dictionaries that are specialized for the particular field of use are employed together with a header transmission format that identifies which dictionaries are to be used. In addition, entries in these dictionaries are categorized by a weighted frequency of use ranking in which the product of the word length in characters and the frequency of occurrence of that word in the text is taken as the weighted figure of merit for ranking words to be placed in the individual dictionaries.