Access method data compression with system-built generic dictionaries
US5561421A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 1994 |
| Grant date | Oct 1, 1996 |
| Priority date | — |
| Expiry date | Jul 28, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/3088
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A computer system constructs a compression dictionary for compressing a character string by interrogating an initial substring portion to determine input string characteristics that are used to select one or more dictionary segments from a library of predetermined dictionary segments individually adapted for compressing strings with particular characteristics. The initial substring portion is dynamically determined during the interrogation. A first set of dictionary segments that meet predetermined automatic selection criteria are selected and a second set of candidate dictionary segments that meet second-level selection criteria are identified for a sampling phase. During the sampling phase, the candidate dictionary segments are alternately used to compress the initial substring portion and determine compression performance statistics. The performance of the dictionary segments in the sampling phase determines which candidate dictionary segments will be added to the first selected dictionary segments, within dictionary total size limits. The first selected dictionary segments and the identified segments constitute a system-built compression dictionary that is used to compress the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.