Information Processing and Novelty Detection
Information is
the result of collecting, processing and organizing data in a way that adds to
the knowledge of the receiver, i.e. the context in which data is taken.
Information as a
concept bears a diversity of meanings and is not the same as data. The concept
of information is closely related to notions of constraint, communication,
control, form, instruction, knowledge, meaning, stimulus, pattern, perception,
and representation.
Information has a
well defined meaning in physics. One example is the phenomenon of quantum
entanglement. Here particles can interact without reference to their separation
or the speed of light. Information itself cannot travel faster than light even
if the information is transmitted indirectly. This could lead to the fact that
all attempts at physically observing a particle with an "entangled"
relationship to another are slowed down, even though the particles are not
connected in any other way other than by the information they carry.
Although data in
everyday language is used as a synonym for information, this is not the case in
the exact sciences. Here we have a clear distinction between data and
information. Data is a measurement that can be disorganized and when the data
becomes organized it becomes information. Data may relate to reality, but also
to fiction. In the former case it consists of propositions, e.g classes of measurements
or observations of a variable. Such propositions may comprise numbers images,
etc.
Novelty detection
is the identification of new or unknown data. It is closely related to change
detection. However, vhange detection is mainly a general way of determining
when a discrete change occurs in a given sequence of data points. It is often
used in data mining, statistics, and dynamic programming.
Finding a needle
in a haystack? There are many ways and means. One may be the central limit theorems (any of
a set of weak-convergence results in probability theory). They all express the
fact that any sum of many independent and identically-distributed random
variables will tend to be distributed according to a particular "attractor
distribution". The most famous CLT. It states that if the sum of the
variables has a finite variance, then it will be approximately normally distributed.
This is demonstrated in this draft
paper by Elena Wildner.
Other data mining
methods include the applications of neural networks, fuzzy logics, etc. This is
often done in combination with feature extraction algorithms like the Principal
Component Analysis, various clustering methods, wavelet transforms, the Hilbert-Huang
transform, etc.