A stacked chip semiconductor device whose size is substantially reduced by high density packaging of two or more semiconductor chips. The alignment mark shielding ring can be constructed of a ring that has a generally L-shaped cross-section, at least one hood portion to function as the shield for the alignment mark, at least one alignment pin for engaging at least one alignment sleeve mounted in a lower chamber shield for holding the alignment mark shielding ring in place. The time-varying signal is analyzed, and the physical activity of the patient is tracking during the time period based on the analyzed time-varying signal. Some embodiments of the invention are designed to provide a brake sensitivity that is adjustable in use. Systems and methods further allow the information to be shared between the various members of the group and which include a series of stages during which it is mainly a question of transferring the modifications from a specific user to the rest of the group, thus avoiding the use of a dedicated client-server structure. A long term SIR is calculated and compared to a TPC quality target.