An aluminum nitride sintered body contains aluminum nitride as a main component, at least one rare earth metal element in an amount of not less than 0. The transcoder includes a decoding unit of an input CELP codec, a transcoding filter, a transcoding filter design unit, and an encoding unit of an output CELP codec. The storage unit stores first and second circuit information which corresponds to first and second compression circuits, respectively. Upon identifying a completion of the transaction, a total cost of the transaction is calculated using the logged data pertaining to each of the plurality of flows.