Someproblemsintheoptimumdesign, such as the peaked effect of noise cancellationand the unstability of specialfrequency, are analysised, and the solvingmethods are introduced.
Just think of mobile phone plans with special rates for calling other mobiles, free calls among family members, introductory offers, cancellation clauses, ring tones, roaming agreements and tracking minutes against plans which change anytime marketing comes up with some new program.