There are many types of fraud, and telephone fraud is a common one (Taniguchi, Haft, Hollmen, & Tresp, 1998).
The literature indicates that the telephone fraud causes losses of two to three billion US dollars each year, and losses from telephone fraud comprises 1.5% to 5% of the total turnover.
The traditional monitoring methods used by fixed-line providers identify abnormal situations after the expiration of a payment period, but by then the loss has
already occurred.
Obviously, traditional monitoring methods do not satisfy the telecom providers’ needs for risk control.