FRIDAY MORNING, 20 MAY 2005 REGENCY E, 8:30 A.M. TO 12:00 ...

11:15
5aNS8. Digital identification of intrusive noise: Pilot study to digitally characterize soundscapes and intrusion. Tim Lavallee
LPES, Inc., 14053 Lawnes Creek Rd., Smithfield, VA 23430, Robert Kull Parsons, Norfolk, VA 23502, and Brigitte
Schulte-Fortkamp ITA/TU-Berlin, Einsteinufer 25, D-10587 Berlin, Germany
One of the difficulties with soundscape investigation and the definition of intrusion is the need for an individual to manually
identify and log specific acoustical events. Event logging can be labor intensive, costly, and difficult to standardize. If information
about physical setting and in situ acoustical signatures can be used to define a given soundscape, event logging could possibly be
performed digitally and intrusion could be defined based on the spectral fingerprint of a given soundscape. Two soundscapes with
different settings and acoustical signatures were identified. Sound time histories and periodic third octave spectra were measured over
a given period. An individual manually logged acoustical events. Independently, algorithms to identify both normal and acoustically
intrusive events for the given soundscape were applied to the data. The digitally identified events were compared to the manually
taken event log. An evaluation of the results will be presented.
11:35
5aNS9. Evaluation of sound environment characteristics: Comparative study between objective and subjective criteria.
Francoise Chartier and Catherine Semidor GRECO, EAPBx, Domaine de Raba F-33400 Talence, France,
catherine.semidor@bordeaux.archi.fr
The evaluation of urban sound environment quality depends on quantitative information as well as the opinion of city dwellers. In
order to underline the relation between objective and subjective points of view, a comparative study was carried out. The subjective
survey consisted in listening to several binaural sound recordings of very short extracts from the urban scene, called ‘‘sonoscene.’’
During these sessions, the listeners’ opinions were noted. The binaural sound recordings are performed in accordance with the
‘‘soundwalk’’ method explained in previous papers C. Semidor, ASA 2004, ASA 2005. The same binaural sound recordings were
analyzed in form of objective criteria such as Equivalent Sound Level, Loudness, Roughness, etc. This paper deals with the comparison
between some of these objective criteria and subjective judgments such as Lack or Presence of traffic noise, Lack or Presence
of human activities, Spatial Dimension, Attractiveness or Annoyance, etc. These first results point out some significant correlations
between Loudness and Attractiveness for example, according to the nature of the sound sources traffic, human activity.
FRIDAY MORNING, 20 MAY 2005
REGENCY B, 8:00 TO 10:00 A.M.
Session 5aPAa
Physical Acoustics: Topics in Acoustic Mine Detection
Murray S. Korman, Chair
Physics Dept., U.S. Naval Academy, Annapolis, MD 21402
Contributed Papers
8:00
5aPAa1. Long-range excitation of vibrational response in landmines
with Rayleigh and Love waves. Thomas Muir Natl. Ctr. for Physical
Acoust., Univ. Mississippi, One Coliseum Dr., University, MS 38677
An experiment was conducted in a clay soil at a range of 25 m from
two types of electromagnetic shaker sources, operating in a cw pulse mode
centered at 100 Hz. The sources were in co-located arrays, one vertically
oriented to generate Rayleigh waves and another transversely oriented to
generate Love waves. Two cylindrical landmine targets were used: an
unloaded empty plastic shell, and a metal shell, loaded with paraffin to
simulate an explosive. These target types represent extreme variations in
what could conceivably be encountered. The targets were instrumented
with three-axis seismometers and accelerometers, and were also viewed
with a laser Doppler vibrometer LDV. Data were acquired on both mine
cases in various stages of deployment, including sitting upon the ground
surface, snugged in to a tight hole in the ground, and completely buried
some 5 cm beneath the surface. The responses of the mine cases to Rayleigh
and Love wave excitation were measured and compared to data from
a reference seismometer deployed nearby, on natural, undisturbed soil.
The mine case responses to these seismic excitation fields, under a number
of conditions are presented and discussed. Work supported by the U.S.
Marine Corps Systems Command.
8:15
5aPAa2. Influence of buried objects on the dynamic nonlinearity of
inhomogeneous materials. Keith Attenborough, Qin Qin Dept. of
Eng., Univ. of Hull, Hull HU6 7RX, UK, Jonathan Jefferis, and Gary
Heald DSTL, Fort Halstead, Kent, UK
Donskoy et al. J. Acoust. Soc. Am. 111, 2705–2714 2002 and Korman
et al. J. Acoust. Soc. Am. 116, 3354–3369 2004 have shown that
the nearby presence of compliant buried objects results in a significant
nonlinear response in the spectrum of surface vibration induced by acoustic
excitation. The latter have suggested that there is a strong connection
with the inherent Nonlinear Mesoscopic Elasticity NME of inhomogeneous
materials. Laboratory experiments are reported that investigate the
comparative NME of granular and fibrous materials and the variation observed
between several states of a single material sand subject to high
sound pressure levels in the frequency range 100 Hz to 2 kHz. Fiberglass
and gravel are shown to have strong inherent nonlinearity whereas wet
compacted sand has relatively little. In both two-tone and single tone
experiments, it is shown that, the presence of buried objects may enhance
or reduce the inherent NME of the embedding medium. In cases where the
NME is enhanced, compliant buried objects have a greater effect than
relatively stiff objects. Work supported by DSTL, UK.
5a FRI. AM
2593 J. Acoust. Soc. Am., Vol. 117, No. 4, Pt. 2, April 2005 149th Meeting: Acoustical Society of America 2593