The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 09, 1987
Filed:
Apr. 17, 1985
Gerald Goertzel, White Plains, NY (US);
International Business Machines Corp., Armonk, NY (US);
Abstract
An adaptive method of file compression is based on the recognition that language can be thought of as a stream of alternating words and separators. Empty dictionaries are created for the words and separators. For each event in the data stream, a determination is made whether the word is in the dictionary for words compiled from the previously encountered words or whether the word is a new word. If the event is a separator, a similar determination is made using the dictionary for separators. If the event is a new word or a new separator, the event is encoded with a predetermined new word or new separator symbol followed by encoding the characters of the word or separator. A count is maintained of all word events and a count is maintained of all separator events as those events are encoded. In addition, individual counts for each occurence of a word and each occurence of a separator are maintained. The ratio of the number of times a word has been encountered to the total number of words encountered is used to estimate the probability of the word. Similarly, the ratio of the number of times a separator has been encountered is used to estimate the probability of the separator. These probabilities are used with a coding scheme, such as arithmetic coding, to code the words and separators in the two dictionaries.