Bone-conduction transducers offer a unique advantage for radio communication systems, allowing sound transmission while the ear canals remain open for access to environmental sounds, or plugged for blocking of environmental sounds. This study compared the intelligibility of noise-degraded speech presented through bone-conduction hearing administered at different locations, and through air-conduction. Speech intelligibility was assessed using the Diagnostic Rhyme Test. Speech intelligibility was reduced for all of the bone-conduction hearing locations, relative to air-conduction hearing. There were also differences in performance for the various bone conduction locations. These results suggest that given noise-degraded speech, the performance decrement from using bone conduction will have to be weighed against the benefits of being able to dynamically block the ear canal, or leave it open, as situations require. Further, the choice of bone conduction transducer location would need to weigh possible performance differences against the various practical advantages of each location.

Standard audio headphones are useful in many applications, but they cover the ears of the listener and thus may impair the perception of ambient sounds. Bone-conduction headphones offer a possible alternative, but traditionally their use has been limited to monaural applications due to the high propagation speed of sound in the human skull. Here we show that stereo bone-conduction headsets can be used to provide a limited amount of interaural isolation in a dichotic speech perception task. The results suggest that reliable spatial separation is possible with bone-conduction headsets, but that they probably cannot be used to lateralize signals to extreme left or right apparent locations

The Federal Aviation Administration is working to modernize the systems used by air traffic controllers through the agency's vision of the Next Generation Air Transportation System. These systems are acquired through the FAA's Acquisition Management System (AMS) process. To date, human factors analysis is included in this process, though improvements can be made in the alignment of human systems integration principles with these systems engineering processes. This paper provides a recommended human systems integration framework to support air traffic management system design, and examines two potential cases in which the framework can be used to support the process.

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