A first enterprise official desires to recover an encryption certificate of a user. In the case of malfunction of an inverter P1 for a generator GN, operation of the inverter P1 is stopped. A packing element is received around the stem assembly in the stem space, and a packing gland is configured to attach to the body and to engage the packing element. A weight of a first interpolation region of the interpolation picture is calculated using distortion energy of the source region. The actual change in basepoint values is combined with last pass values of the plurality of basepoint values to produce an updated basepoint estimate.