The present invention provides a porous semiconductive structure, characterized in that the structure has an electrical conductivity of 5\xb710\u22128 S\xb7cm\u22121 to 10 S\xb7cm\u22121, and an activation energy of the electrical conductivity of 0. This process involves initially estimating the channel impulse response. A design controlled plant including the all-pass filter is determined. Advantageously, by pre-fabricating the lacrosse pocket, the need to \u201cwork\u201d the netting into the desired shape is eliminated, and a player can quickly and easily change pockets as necessary. Thus, a customer receiving the lot uses the system to trace the lot and determine any important characteristics. A fastener prevents migration of a guidewire or catheter during the procedure.