compression
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compression
Engineering an increase in pressure of the charge in an engine or compressor obtained by reducing its volume
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
Compression
Direct pushing force, in line with the axis of the member: the opposite of tension.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved
compression
[kəm′presh·ən] (computer science)
(electronics)
Reduction of the effective gain of a device at one level of signal with respect to the gain at a lower level of signal, so that weak signal components will not be lost in background and strong signals will not overload the system.
(geodesy)
(geology)
A system of forces which tend to decrease the volume or shorten rocks.
(mechanics)
Reduction in the volume of a substance due to pressure; for example in building, the type of stress which causes shortening of the fibers of a wooden member.
(mechanical engineering)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
compression
1. The state of being compressed, or being shortened by a force.
2. The change in length produced in a test specimen by a compressive load.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
flattening
The ratio of the difference between the equatorial radius (major semi-axis) and the polar radius (minor semi-axis) of the earth to the equatorial radius. Also called compression. The flattening of the earth is the ellipticity of the spheroid, and it equals the ellipticity of the ellipse forming a meridianal section of the spheroid. If a and b represent the major and minor semi-axes of the spheroid, respectively, and f is the flattening of the earth, f= (a – b)/a. The magnitude of the flattening is sometimes expressed by stating the numerical value of the reciprocal of the flattening, a/(a – b).
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
compression
(application)(Or "compaction") The coding of data to save
storage space or transmission time. Although data is already
coded in digital form for computer processing, it can often be
coded more efficiently (using fewer bits). For example,
run-length encoding replaces strings of repeated characters
(or other units of data) with a single character and a count.
There are many compression algorithms and utilities.
Compressed data must be decompressed before it can be used.
The standard Unix compression utilty is called compress though GNU's superior gzip has largely replaced it. Other compression utilties include pack, zip and PKZIP.
When compressing several similar files, it is usually better to join the files together into an archive of some kind (using tar for example) and then compress them, rather than to join together individually compressed files. This is because some common compression algorithms build up tables based on the data from their current input which they have already compressed. They then use this table to compress subsequent data more efficiently.
See also TIFF, JPEG, MPEG, Lempel-Ziv Welch, "lossy", "lossless".
Compression FAQ.
Web Content Compression FAQ.
Usenet newsgroups: news:comp.compression, news:comp.compression.research.
The standard Unix compression utilty is called compress though GNU's superior gzip has largely replaced it. Other compression utilties include pack, zip and PKZIP.
When compressing several similar files, it is usually better to join the files together into an archive of some kind (using tar for example) and then compress them, rather than to join together individually compressed files. This is because some common compression algorithms build up tables based on the data from their current input which they have already compressed. They then use this table to compress subsequent data more efficiently.
See also TIFF, JPEG, MPEG, Lempel-Ziv Welch, "lossy", "lossless".
Compression FAQ.
Web Content Compression FAQ.
Usenet newsgroups: news:comp.compression, news:comp.compression.research.
compression
(multimedia)Reducing the dynamic range of an audio signal,
making quiet sounds louder and loud sounds quieter. Thus,
when discussing digital audio, the preferred term for reducing
the total amount of data is "compaction". Some advocate this
term in all contexts.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Compression
(in Russian, kompressiia), a force effect on a gaseous body that reduces the volume occupied by the gas and increases its pressure and temperature. Compression is achieved by means of compressors and during the operation of internal combustion engines and other equipment.
Russian technical literature usually uses the word szhatie instead of kompressiia, although the meaning of the former is more general, since it also covers solids and volume reduction upon cooling.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.