Woodbury, New York, November 14, 1997
Do Long Islanders possess more vowels in their repertoire than other Americans? In what ways does the weather affect communication between animals? Can computers truly master the art of jazz improvisation?
These and other questions will be addressed at the 134th Meeting of the Acoustical Society of America (ASA), to be held December 1-5, 1997 at the Town and Country Hotel, San Diego, California. At the meeting over 670 papers will be delivered. With nearly 7000 members, the ASA is the largest scientific organization in the United States devoted to acoustics.
Many English speakers on Long Island possess an extra "front vowel," a vowel sound made with the tongue positioned relatively close to the front of the mouth. Many American speakers only have 5 front vowels--and consequently will pronounce the vowels in the words "cap" and "cab" the same way. But many Long Islanders will pronounce "cab" with an "ayuh" sound. Studying this issue in the heart of Long Island, Marie Huffman and Elyse Tamberino of the State University of New York at Stony Brook have found that to distinguish Long Island vowels, especially front vowels, from others, it has been useful to analyze their "spectral change." In spectral change studies, one determines how the frequencies in the vowel sound change over time, as the vowel sound is pronounced. (Paper 2aSC21)
Jazz musicians are frequently called upon to improvise--instantly compose and perform music based on what the other musicians are playing. Now, computer scientists and musicians are developing software attempting to perform this sophisticated task. (Session 4pMU) Vijay Iyer of UC-Berkeley (firstname.lastname@example.org) will present a computer program that can produce improvised "grooves," the rhythms that are often collectively produced from the interaction of several musicians. (4pMU5) John Biles (email@example.com) of the Rochester Institute of Technology will demonstrate GenJam, a computer program that can trade 8-bar solos in real time with human performers. (4pMU1)
American bullfrogs (Rana catesbeiana) make characteristic low-pitched vocal calls that travel considerable distances. Astoundingly, Alejandro Purgue of UCLA (firstname.lastname@example.org) has discovered that the frogs amplify and broadcast their low-pitched sounds through an unlikely place: their ears. Checking if this phenomenon occurs in other frogs, Purgue has since found that another species (Rana pipiens) uses its ears as loudspeakers, but the barking treefrog (Hyla gratiosa) uses other areas, such as the lungs and vocal sacs, to radiate its sounds. (4pABa2)
When inspecting newly manufactured fuel tanks for cars, quality-control engineers must detect and pinpoint places where leaks may occur. Traditional methods have been either time-consuming or unreliable. Now, Serdar Yonak and David Dowling (313-936-0423) of the University of Michigan have developed a "photoacoustic" system for detecting these leaks. In this technique, a laser heats up the device of interest, generating telltale vibrations which can be picked up by a network of microphones to detect and locate places where gas may leak. Whereas photoacoustics has been previously used to detect the presence of small leaks, this is the first system that can pinpoint the location. (3pEA2)
The animal world is filled with examples of advanced acoustical systems that far outstrip the capabilities of late 20th-century science and engineering. For example, the dolphin's "echolocation" system is perhaps the world's most complex sonar system for shallow waters and over short distance ranges. (1eID1) As another example, the human cochlea (inner ear) can detect sounds with intensities that vary by a factor of a million, yet it is extremely efficient, dissipating less than a thousandth of a watt in the process. At two sessions (3aABb and 4aAB), scientists will show how they are applying lessons from these biological structures to develop improved artificial devices. Examples include a silicon-based cochlea (4aAB3), and a dolphin-like sonar system that can identify whether a coin is heads or tails. (4aAB1)
Developing a new approach for testing the general strength and toughness of materials, researchers have married two well-developed techniques in acoustics: the use of ultrasound pulses to generate pressure waves in materials; and methods for monitoring the complicated acoustical emissions of solid objects. Unlike other techniques for evaluating materials, acousto-ultrasonics is not primarily concerned with detecting a single, critical defect in a material. Rather, it detects overall effects (such as a reduction of material strength) which are caused collectively by non-critical flaws in the material. (Session 2aEA) Henrique Reis (217-333-1228) of the University of Illinois will discuss how acousto-ultrasonics has been used to evaluate steel-belted radial truck tires. (2aEA1)
At the last ASA Meeting in June, researchers discussed how classrooms often suffer from poor acoustics and large amounts of background noise, making it surprisingly difficult even for students with good hearing to perceive speech. In efforts to understand better the extent of this problem, Dean Heerwagen of the University of Washington (206-543-2334) and his colleagues are performing a pilot study of classroom acoustics in a Seattle elementary school. The study has tested how well children from grades 1-5 hear speech in various room conditions, such as when a typical heating, ventilation, and air-conditioning (HVAC) system is turned on. (2pNSa1)
To improve our understanding of earthquakes and other seismic processes, scientists perform geodesy, the study of the Earth's surface, particularly geometrical features such as its shape. While satellites and other instruments have performed powerful geodesy studies of land, by using methods that employ light, comparable techniques do not exist for geodesy on the ocean floor. Fred Noel Spiess of UC-San Diego (619-534-1621) will describe how long-range ocean geodesy is now possible by combining the Global Positioning System with acoustical techniques. (1pA01) Underwater geodesy techniques have provided evidence for the large-scale migration of fluid underneath the Juan de Fuca ridge, located in the northeast Pacific Ocean between the Pacific and Juan de Fuca plates (1pAO2)
The howl of a wolf, the roar of a lion, the chirping of a bird--weather conditions such as temperatures and winds can greatly influence how far these animal calls can be heard. Studying the low-pitched calls of African elephants, David Larom of UC-San Diego (email@example.com) and his colleagues have found that weather conditions can cause a tenfold expansion or contraction in the size of the elephant's calling area in a single day. In fact, coyotes and wolves may have evolutionarily adapted a preference to call during the night in part because weather conditions in their native habitats maximize their chances of being heard over the longest possible distances. (3aABb8) Caitlin O'Connell of UC-Davis (firstname.lastname@example.org ) has detected relatively far-traveling seismic waves in elephant vocalizations and movement, suggesting a possibility for their use in long-distance communication. (3aABb7)
While warming up before a performance or practice, professional classical singers use the technique known as "messa di voce," which means "to place the voice." In this exercise, a singer must gradually increase volume (crescendo), then gradually decrease it (decrescendo), while singing the same note and vowel. Investigating this process in 6 well-trained singers, Ingo Titze (319-335-6600) and his colleagues at the University of Iowa have found that the singers produced fine examples of messa di voce by doing such things as varying air pressure in the region under the vocal cords and moving the abdomen. Although the singers performed these exercises by controlling the same regions of the body, they differed greatly in their dynamic range, the difference in volume between the loudest and softest sounds. (2aMu1)
When individuals file a lawsuit alleging hearing loss from improper exposure to noise, lawyers must estimate the relative contributions of the different sources of hearing loss, such as the aging process, and noise exposure during various time periods and settings. Speakers at session 3aNS will discuss how to allocate hearing loss in medical and legal situations. They will address such questions as: How can new national and international occupational noise standards (such as ISO 1999 and ANSI S3.44) help provide a framework for court cases? Do the effects of noise exposure from multiple sources ever add together in a simple way, or do they interaction in a complex fashion? Do standard hearing tests provide enough information on the true status and condition of the person's hearing system?
For more information before, during, and after the meeting contact Ben Stein, email@example.com, or 301-209-3091. At the meeting, contact Elaine Moran (firstname.lastname@example.org) at the ASA registration desk, 619-291-7131 (12/1-12/5).
For a printed copy of the meeting program contact Karin Heineman, AIP, email@example.com, with your postal address.
For lay language versions of selected meeting papers, visit the ASA World Wide Press Room ( www.acoustics.org) starting the week of November 17.
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