Noise
"In general usage, noise can be considered data without meaning; that is, data that is not being used to transmit a signal, but is simply produced as an unwanted by-product of other activities. In Information Theory, however, noise is still considered to be information." (Wikipedia, 2005).
One of the key additions that Claude E Shannon made in his Information theory as a further development of the work of Nyquist and Hartley was the formal integration of noise into the communication model. Noise is introduced into the channel between the transmitter and the receiver and acts to changes messages so that what is received differs from what is transmitted. In information theory is the relation between signal and noise a major concern.
A differentiation has been made between physical noise and semantic noise. Physical noise may be, for example, unwanted electrical interference on the signal wires or flicker on the TV. Physical noise is also a problem in libraries (cf., Eagan, 1991).
Semantic noise, on the other hand, may be the use of different codes, i.e. messages you do not understand. In Library and Information Science (LIS) are non-relevant retrieved documents sometimes termed noise.
Non-relevant documents retrieved in a search are sometimes named noise, cf. Precision
Literature:
Eagan, A.
(1991). Noise in the library: Effects and control. Wilson Library Bulletin,
65(6), 44-47.
Wikipedia. The free encyclopedia. (2005). Noise. http://en.wikipedia.org/wiki/Noise
See also: Relevance (Epistemological lifeboat).
Birger Hjørland
Last edited: 03-09-2006