In
telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...
, data compaction is the reduction of the number of
data element
In metadata, the term data element is an atomic unit of data that has precise meaning or precise semantics. A data element has:
# An identification such as a data element name
# A clear data element definition
# One or more representation term ...
s,
bandwidth, cost, and time for the generation,
transmission, and
storage of data without loss of
information
Information is an Abstraction, abstract concept that refers to something which has the power Communication, to inform. At the most fundamental level, it pertains to the Interpretation (philosophy), interpretation (perhaps Interpretation (log ...
by eliminating unnecessary
redundancy, removing irrelevancy, or using special coding.
Examples of data compaction methods are the use of fixed-
tolerance bands, variable-tolerance bands,
slope-keypoints, sample changes, curve patterns,
curve fitting, variable-
precision coding,
frequency analysis, and probability analysis.
Simply squeezing noncompacted data into a smaller space, for example by increasing packing density by transferring images from
newsprint
Newsprint is a low-cost, non-archival paper consisting mainly of wood pulp and most commonly used to print newspapers and other publications and advertising material. Invented in 1844 by Charles Fenerty of Nova Scotia, Canada, it usually has ...
to
microfilm or by transferring data on
punched card
A punched card (also punch card or punched-card) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widel ...
s onto
magnetic tape
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...
, is not data compaction.
Everyday examples
The use of
acronym
An acronym is a type of abbreviation consisting of a phrase whose only pronounced elements are the initial letters or initial sounds of words inside that phrase. Acronyms are often spelled with the initial Letter (alphabet), letter of each wor ...
s in
texting is an everyday example. The number of bits required to transmit and store "
WYSIWYG" (What You See Is What You Get) is reduced from its expanded equivalent (7 characters vs 28). The representation of
Mersenne prime
In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 1 ...
s is another example. The largest known is over 17 million digits long but it is represented as ''M''
57885161 in a much more compacted form.
See also
*
brevity code
Brevity is concision or brevitas, the quality of being brief or concise, or:
* Brevity (comic strip), ''Brevity'' (comic strip), a comic strip created by Guy Endore-Kaiser and Rodd Perry
* Brevity code, a vocal word replacement system
* Operation ...
*
commercial code (communications)
In telecommunication, a commercial code is a code once used to save on cablegram costs. Telegraph (and telex) charged per word sent, so companies which sent large volumes of telegrams developed codes to save money on tolls. Elaborate commercial cod ...
*
data compression
References
Telecommunications techniques
Data compression
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