A changeable cover for an electronic device and method of using same in a payment system is provided. The correction value computing units include correction value smoothing units for obtaining smoothed correction values. based on a quantity proportional to the received signal code power for the candidate cell and carrier frequency and inversely proportional to a measure of total interference in the candidate cell on the carrier frequency. Also provided are ligands specific for cancer cells. Additional alloying elements in the commercial Cu alloys such as Fe, Cr, Si, Mn, Sn and Zn are unavoidable.