NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
NASA Scientific and Technical Aerospace Reports
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20060001730 Naval Underwater Systems Center, New London, CT, USA<br />
Passive Ranging in Multipath-Dominated Environment<br />
Hamilton, Miriam; Schultheiss, Peter M.; IEEE International Conference on Acoustics, Speech, <strong>and</strong> Signal Processing<br />
(ICASSP ‘87); Volume 1; 1987, pp. 12.7.1 - 12.7.4; In English; See also 20060001583<br />
Contract(s)/Grant(s): N00014-80-C-0092; Copyright; Avail.: Other Sources<br />
At long ranges the Cramer-Rao lower bound on passive ranging error is proportional to the fourth power of the<br />
range-to-array-baseline ratio. This behavior results from the diminishing wavefront curvature observed by an array at long<br />
ranges, <strong>and</strong> leads to unacceptable performance in many applications of interest. If energy arrives over two different paths one<br />
can measure the differential delay between the arrivals <strong>and</strong> use it to improve the range estimate. This paper demonstrates that<br />
the resulting improvement in range accuracy can he very substantial when the propagation conditions encountered by the two<br />
arrivals are known precisely. Even modest uncertainties concerning propagation conditions can seriously limit that<br />
improvement. With large uncertainties one generally cannot achieve significant improvements over single path measurements.<br />
Author<br />
Multipath Transmission; Sound Ranging<br />
20060001797 Southern Methodist Univ., Dallas, TX USA<br />
Evidence for an Infrasound Waveguide<br />
Herrin, Eugene; Kim, Tae Sung; Stump, Brian; Nov. 1, 2005; 8 pp.; In English<br />
Contract(s)/Grant(s): W9113M-05-0018<br />
Report No.(s): AD-A440255; No Copyright; Avail.: CASI: A02, Hardcopy<br />
On May 30, 2005, eight strongly dispersed infrasound signals were recorded at one seismo-acoustic array in the Republic<br />
of Korea. Phase-matched filtering (Herrin & Goforth, 1977) <strong>and</strong> a forward modeling technique were used to determine the<br />
nature of the dispersion. The most likely explanation for these dispersed infrasound signals is that the dispersion is due to<br />
propagation down a low-velocity waveguide: This can be characterized as an ephemeral ‘SOFAR’ layer in the atmosphere.<br />
DTIC<br />
Infrasonic Frequencies; Waveguides<br />
20060001884 Naval Research Lab., Washington, DC USA<br />
Volume Sensor Development Test Series 2 - Lighting Conditions, Camera Settings, <strong>and</strong> Spectral <strong>and</strong> Acoustic<br />
Signatures<br />
Lynch, James A.; Gottuk, Daniel T.; Rose-Pehrsson, Susan L.; Owrutsky, Jeffrey C.; Steinhurst, Daniel A.; Minor, Christian<br />
P.; Wales, Stephen C.; Williams, Frederick W.; Farley, John P.; Nov. 24, 2004; 134 pp.; In English; Original contains color<br />
illustrations<br />
Report No.(s): AD-A440439; NRL/MR-MM/6180--04-8843; No Copyright; Avail.: Defense <strong>Technical</strong> Information Center<br />
(DTIC)<br />
Real-scale fire tests in mock ship compartments were conducted to collect data of acoustic <strong>and</strong> spectral sensors <strong>and</strong> to<br />
experimentally evaluate the fire detection performance of three commercially available video image fire detection systems<br />
under various lighting <strong>and</strong> camera setting configurations. One goal was to establish an underst<strong>and</strong>ing of the performance<br />
sensitivity <strong>and</strong> limitations of the VID systems to various setup <strong>and</strong> environmental conditions that may occur onboard ship. The<br />
performance of the detections systems was compared to the response of multiple state-of-the-art smoke detection technologies<br />
for a range of fire <strong>and</strong> nuisance source exposures. Additionally, these tests provide a large database of information to evaluate<br />
the spectral <strong>and</strong> acoustic signatures of the various fire <strong>and</strong> nuisance sources. Toward this end, microphones, long wave-length<br />
video imaging <strong>and</strong> a test bed of single <strong>and</strong> multiple element sensors were included in the tests.<br />
DTIC<br />
Acoustic Properties; Cameras; Damage; Fires; Illuminating; Signatures; Spectra; Spectral Signatures<br />
20060002505 Columbia Univ., NY, USA<br />
A Quantitative Evaluation of Singing through Electromyography<br />
Shan, Jing; Visentin, Peter; Shan, Gongbing; The IPSI BgD Transactions on Advanced Research. Multi-, Inter-, <strong>and</strong><br />
Trans-disciplinary Issues in Computer Science <strong>and</strong> Engineering, Volume 1, Number 2; July 2005, pp. 31-36; In English; See<br />
also 20060002498; Original contains black <strong>and</strong> white illustrations; Copyright; Avail.: CASI: A02, Hardcopy<br />
Electromyogram (EMG) measures electrical activity associated with neural firings in musculature. Such bio-signals can<br />
be used to quantify muscle activity. Since singing is a human biocultural phenomenon, there should exist a connection between<br />
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