A method of growing a nitride semiconductor crystal which has very few crystal defects and can be used as a substrate is disclosed. A DC offset estimator and a frequency offset estimator operate concurrently to produce estimates of DC and frequency offsets of the data packet, which are determined from a portion of the preamble as it is received. The restraining mechanism is then released to allow the annular support structures to expand into conforming engagement with the inner wall of a lumen in which the prosthesis is to be deployed. A hydraulic strut extends between an upper lift pivot and a lower lift pivot. A test case generator selects test values for test operations based on the weight value for the associated test value.