Browsing by Type "Conference Proceedings (CP)"
Now showing items 161-180 of 314
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Martinus - multiprocessor for high capacity real-time processing
(NATO. SACLANTCEN, 1979/12)Development of circuit technology in recent years now makes it feasible to build powerful processing machines at quite considerable savings - in comparison to those which have been considered feasible earlier. These savings ... -
MASCOT - a modular software construction system
(NATO. SACLANTCEN, 1979/12) -
Measurement and interpretation of angular spreading from multiple boundary interactions in a shallow water channel
(NATO. SACLANTCEN, 1997)The problem of angular spreading of sound that has undergone multiple boundary scattering (both sea surface and sea bed) in a shallow water channel is discussed. Measurements made of the horizontal spatial coherence along ... -
Measurement of the bubble population in coastal waters using combination frequencies of MHz order
(NATO. SACLANTCEN, 1997)This paper describes the use of a combinatron frequency technique to measure the size distribution of oceanic bubbles. Written between two sea trials, the paper describes how the apparatus cart be adapted to design tests ... -
Measurements of normal-mode amplitude functions in a nearly-stratified medium
(NATO. SACLANTCEN, 1975/10)In normal-mode treatments of acoustic propagation in nearly-stratified media, calculations are frequently based on the perfectly-stratified medium model, in which symmetry permits separation of the wave equationo In these ... -
Medium-induced low-frequency fluctuations in acoustic transmission loss: examples from measurements in selected geographical areas
(NATO. SACLANTCEN, 1986/06)The ocean is a complex, highly variable acoustic nedium. A propagating acoustic signal is affected by a host of phenomena, including the sea-surf ace and bottom, volume inhomogenei ties, internal waves and tides, and ... -
Methods used in France for the calculation of sound fields
(NATO. SACLANTCEN, 1971/12) -
Mobile range for measuring ship radiated acoustic noise
(NATO. SACLANTCEN, 1985/01)The Mobile Range described in this paper allows measurements of noise radiated from both surface ships and submarines in open seas with bottom depths from less than lOOm to 400 meters. The range is being developed and built ... -
Model-aided data adaptive suppression of reverberation
(NATO. SACLANTCEN, 1993/08)We propose a processing methodology which is based on the piece-wise modeling, adaptive estimation, and removal of reverberation components. An important feature of this approach is that backscatter models and information ... -
Modeling of subcritical penetration into sediments due to interface roughness
(NATO. SACLANTCEN, 1997)Recent experimental results reveal acoustic penetration into sandy sediments at grazing angles below the critical angle. We have been investigating a mechanism for subcritical penetration based on scattering at a rough ... -
Modeling range-dependent, high-frequency, shallow-water torpedo reverberation data
(NATO. SACLANTCEN, 1997)The high-frequency, forward bottom losses predicted by a lossy Rayleigh and a Biot poroelastic sediment model are substantially different. These differences will accumulate and become measurable in multiple bottom bounce ... -
Multipath field representation for seabed parameter extraction using backscatter data from shadow zones
(NATO. SACLANTCEN, 1997)Inversion strategies for bottom parameter estimation in shallow water impose stringent requirements on accuracy and speed of acoustic models. We highlight the importance of second order effects as first order determinants ... -
Multistatic bottom reverberation in shallow water
(NATO. SACLANTCEN, 1997)A wavenumber integration approach to modeling of the full multistatic reverberant field produced by small-scale bottom roughness in stratified shallow water waveguides has been developed. A perturbation approach to rough ... -
Mutual coherence and silence
(NATO. SACLANTCEN, 1985/01)In this paper we are developing the theoretical principle of a modification of the acoustical emission by a ship. Its objective is making inefficient the angular measurements achieved by a detector. More precisely, the ... -
Near field propeller radiated noise measurements: model and full scale experimental data comparison
(NATO. SACLANTCEN, 1985/01)The ever rising interest related to the underwater no1se originating from cavitating propellers prompted the Italian Navy to study this aspect of naval architecture in an experimental way. This was accomplished carrying ... -
Noise sources in the ocean - part 1
(NATO. SACLANTCEN, 1975/10)Following a brief historical survey of the development of our knowledge of the origins and characteristics of ambient noise in the ocean, the principal known sources of noise are described. These are: environmental origin, ... -
Noise sources in the ocean - part 2
(NATO. SACLANTCEN, 1975/10)Following a brief historical survey of the development of our knowledge of the origins and characteristics of ambient noise in the ocean, the principal known sources of noise are described. These are: environmental origin, ... -
NOSC signal processing evaluation laboratory
(NATO. SACLANTCEN, 1979/12)A new acoustic Signal Processing Evaluation Laboratory (SPEL) at the Naval Ocean Systems Center (NOSC), San Diego, is described. This laboratory has been designed to support a broad program of research and development of ... -
Notes on the interpretation of ambient noise statistics
(NATO. SACLANTCEN, 1982/06)Interpretation of statements about the character of ambient sea noise, as well as schemes to measure or model noise, are sensitive to the context or underlying view of what is essentially a stochastic process. A framework ... -
Numerical modelling of acoustic scattering by smooth inclusions in a layered fluid-solid medium
(NATO. SACLANTCEN, 1997)A boundary integral equation (BIE) method as descnbed for computing the scattering of a monofrequent acoustic field by a smooth, rigid 30 object in a layered range-independent fluid-solid medium. The BIE is discretized ...