A combined signal is received over a shared spectrum in a time slot in a time division duplex communication system using code division multiple access. The serial data transfer apparatus transmits and receives data with a destination apparatus via a serial bus. In response, the system determines a number of potential complaints of water contamination in the geographic area by applying the number of one or more correlated sources of water contamination located in the geographic area. The present invention is further configured to enable processing core and memory utilization by external systems through virtualization. Each longitudinally extending section is configured to overlie at least two stringers of a respective fuselage section. The method may comprise the acts of detecting a second security module, determining whether a key associated with the second security module is available to the first security module, and obtaining the key associated with the second security module if the key associated with the second security module is not available to the first security module.