Systems and methods for activating a down hole tool in a wellbore. The method also includes comparing the frame that precedes the missing frame to the received frames to identify a selected frame. The present invention further concerns a suspended ceiling comprising said sound absorbing module. The front wheels are connected to each other by a steering linkage, consisting of two equal length members pinned to each other at a connection point. The multiprocessor computing system further includes a partitioning system for using the snoop units to partition the multitude of processing units into a plurality of independent, memory-consistent, adjustable-size processing groups.