Underwater communication has always been a challenge, but a new modeling technique could help users go wireless by automatically setting acoustic modems for maximum speed. Many applications, such as monitoring a submerged volcano or listening to whale songs, require underwater sensors, but using cables to retrieve this data can be expensive and impractical. An alternative for staying connected would be to send acoustic signals through the water, in the same way that Wi-Fi signals travel through the air. However, these sub-surface messages tend to become garbled as the sound waves scatter off of various objects in the water. Much of this unwanted echo comes from the ocean surface, where the sound reflects in constantly changing directions due to the undulating water waves.
To help underwater wireless communicators, Geoffrey Edelmann of the U.S. Naval Research Laboratory and his colleagues have developed a method for predicting how good the acoustics are in a given stretch of ocean. The software first constructs a model of the current sea surface using input from a floating buoy or other device. It then takes this simulated ocean and calculates all the different sound wave paths and how they interfere with each other. The results tell a user exactly how fast they can reliably send their data at the present time. The research team plans to test their model this coming summer in a real ocean setting.
The talk, "Ocean surface degradation of shallow water acoustic communication" (5aSP1) by Geoffrey Edelmann, Shaun Anderson, and Paul Gendron is at 9:00 a.m. on Friday, November 14.
4) MUSICIANS HEAR MORE PARTICULARLY
A new comparison of how musicians and non-musicians listen to sound shows that the benefits of musical training are not limited to music, but may help people listen in a variety of situations. Musical training enhances and sharpens the nervous system's response to speech particularly in background noise and to
|Contact: Jason Bardi|
American Institute of Physics