A method of storing information relating to the transmission of messages by an
entity over a given time period comprises the step of creating a signature comprising
a plurality of parameters related to the transmission of messages over that time
period wherein the parameters comprise at least one parameter related to the transmission
of messages over a portion of the period and also related to the position of the
portion in the period, to enable output data to be derived from the stored information.
The signature may be updated by a weighted averaging process with other more recent
signatures. Application in fraud detection where signature representing information
in many call detail records from a particular subscriber is fed to a neural network.
