Browsing CMRE Publications by Type "Conference Proceedings (CP)"
Now showing items 301-314 of 314
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Time dependence of infrasonic ambient seafloor noise on a continental shelf
(NATO. SACLANTCEN, 1986/06)SACLANTCEN is conducting a long term programme of ambient noise measurements that cover the frequency band from 1 to 100 Hz. A sea-bed sensor consisting of three seismometers and a hydrophone has been deployed close to the ... -
Time domain finite difference methods for range dependent Biot media
(NATO. SACLANTCEN, 1997)The physics of sound propagation in saturated, porous (Biot) media differs from propagation in fluids and elastic/anelastic solids because of the existence of a second compressional wave, the "slow" wave. Many environments ... -
Time-frequency representation of model based high frequency broad band scattering from a rough interface
(NATO. SACLANTCEN, 1997)A formulism for scattering a broad band high frequency pulse from a randomly rough surface of n penetrable oceanic sediment is developed and used to investiyate the ability of local cosine transform (LCT) rime-frequency ... -
Two dimensional internal-wave spectra
(NATO. SACLANTCEN, 1975/10)Although spatial fluctuations of the sound speed in the ocean have a variety of causes, internal waves are thought to produce most of the fluctuations over horizontal scales ranging from several tens of metres to several ... -
Underwater acoustics - modelling: keynote address
(NATO. SACLANTCEN, 1975/10) -
Underwater ambient noise: proceedings of a conference held at SACLANTCEN on 11-14 May 1982, vol. 2 - Unclassified Papers, part 2
(NATO. SACLANTCEN, 1982/06)Contents: PROCESSING TECHNIQUES--A method of estimating the influence of ship's noise on ambient noise measurements; Optimal detection and tracking of acoustical noise sources in a time-varying environment; Influence of ... -
Uniqueness problems in extracting environmental parameters from high-frequency shallow-water reverberation measurements
(NATO. SACLANTCEN, 1997)Inversion techniques that extract environmental parameters from measured reverberation often lead to mathematical problems that are not well-posed. Two examples illustrate this possibility. The first hows how a model can ... -
User-orientated software for signal analysis
(NATO. SACLANTCEN, 1979/12)A conflict exists between dedicated analysis instruments which are easy to use but inflexible and general purpose computers which are adaptable but require program development. A software package has been. developed which ... -
Using intelligent graphics terminals in real-time processing
(NATO. SACLANTCEN, 1979/12)At the Naval Research Laboratory intelligent graphics terminals are being utilized for real-time acquisition, storage, processing and display of oceanographic data when mini-computer systems are inappropriate. The intelligent ... -
Vertical porosity and velocity fluctuations in shallow-water surficial sediments and their use in modeling volume scattering
(NATO. SACLANTCEN, 1997)Variability in sediment porosity and velocity creates volume scattering which is a parameter used in high-frequency scattering models. High-resolution vertical profiles of sediment porosity and compresstonal wave velocity ... -
Very-high (cm scale) resolution multichannel seismology
(NATO. SACLANTCEN, 1997) -
Wavefront curvature ranging as a passive synthetic aperture problem
(NATO. SACLANTCEN, 1997)A new method of wavefront curvature passive ranging is introduced that is based on a model-based approach. The signal and measurement systems are placed into state-space form, thereby allowing the unknown parameters of the ... -
Wavelet analysis of side scan sonar imagery for classification
(NATO. SACLANTCEN, 1997)Wavelet-based techniques are presented for compressing side scan sonar images communicated from UUV's through band limited communication channels. Testing with an automatrc classifier on reconstructed images demonstrates ...