Browsing Reprints by Issue Date
Now showing items 21-40 of 548
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Application of ray tracing with horizontal gradient to monostatic boundary reverberation
(NATO. SACLANTCEN, 1971/12)Presented is the current work being done at the Naval Research Laboratory (NRL) on the development of a series of computer programs to predict long range, low frequency, monostatic boundary reverberation. The emphasis is ... -
Oceanic-acoustic experiments at SACLANTCEN
(NATO. SACLANTCEN, 1971/12)Last year, at the Director's suggestion, a project in oceanicacoustics was set up at the Centre with scientists from at least 3 groups playing some part in the planning and execution of experiments. The p roject represents ... -
Hamiltonian methods in hydro-acoustic propagation
(NATO. SACLANTCEN, 1971/12)The investigation that I wish to outline here originated in the military need of forecasting detection p r obabilities of underwater acoustic emitters, in case s in which only a somewhat general idea of the sound speed ... -
Oceanic layered microstructure and fronts
(NATO. SACLANTCEN, 1971/12)This talk is divided into two parts: one deals with oceanic microstructure, with particular attention to the so-called "layered microstructure"; the other part is concerned with oceanic fronts. As an example of the latter ... -
A review of some developments in ray tracing at the Naval Air Development Center
(NATO. SACLANTCEN, 1971/12)The Naval Air Development Center has a comprehensive ray-tracing program which has been extensively used for a number of years not only by our own laboratory, but also by other naval activities and private contractors . ... -
Rays and statistical diffraction theory
(NATO. SACLANTCEN, 1971/12)A method of extending ray tracing is proposed, such that mediumscale irregularities of a statistical nature are taken into account along with large-scale irregularities in refractive index of the medium. -
Comparison of propagation measurements obtained using the MEDUSA system with computer modelled data
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Calculation of propagation losses in a medium with a velocity profile approximated by a number of Epstein profiles
(NATO. SACLANTCEN, 1971/12)This paper presents a digital ray-theory program, by which the ray trace, travel time and intensity can be calculated for velocity profiles approximated by a number of Epstein functions. -
Intensity at caustics
(NATO. SACLANTCEN, 1971/12)The classical divergence expressions predict an infinite intensity at caustics. This infinite intensity is a fundamental limitation of geometrical acoustics (ray theory). The intensity at a caustic is of primary concern ... -
Summary and recommendations
(NATO. SACLANTCEN, 1971/12)An unfortunate first impression might be that ray tracing is dull, simply because the idea is a very old one. In fact, ray tracing is the single most powerful method available to us for understanding the complexities of ... -
Intensity calculations along a single ray
(NATO. SACLANTCEN, 1971/12)A method is presented for the calculation of sound intensity using only one ray. The sound velocity profile is assumed to be continuous up to the second derivative and it is supposed that the ray equations are solved ... -
Comments on the ray theory approximation
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An experimental verification of a geometric acoustic approximation
(NATO. SACLANTCEN, 1971/12)This paper sets out to show that a very simple ray treatment may be used to give a surprisingly good estimate of a sound field, even in conditions where the criteria for the use of geometric acoustics are apparently not fulfilled. -
Comparison of CONGRATS ray tracing predictions with MEDUSA measurements of reverberation
(NATO. SACLANTCEN, 1971/12)From the user's point of view, ray tracing is just a computer procedure which is inserted into larger programs of different degrees of complexity . The following table indicates in which kind of programs this procedure is ... -
Geometrical properties of underwater sound propagation
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Experimental data on the refraction of underwater explosion pulses
(NATO. SACLANTCEN, 1971/12)There are several reasons why a researcher in underwater acoustics might be interested in the use of explosion pulses as sources. The most generally recognized reason is that explosions are convenient and powerful sources ... -
A survey of practical considerations relative to the processing and analysis of underwater acoustic signals
(NATO. SACLANTCEN, 1972/05)An investigation, aimed at bringing into sharper focus · tb~ strong interrelationships that exist between the measurement, p r o c essing, and analysis of underwater acoustic signals, is conducted. Emphasis is on practical ... -
Processing of broadband acoustic signals
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The SACLANTCEN interactive time series analysis system
(NATO. SACLANTCEN, 1972/05)The purpose of this paper is to describe the new conversational signal processing system which is being developed by the Computer Section at SACLANTCEN. This system, which i ncludes input/ output devices, can be used alone ... -
Digital acoustical processing at Woods Hole Oceanographic Institution
(NATO. SACLANTCEN, 1972/05)