Download or read book Le cri de guerre des Prussiens written by and published by . This book was released on 1860 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Inversion for Subbottom Sound Velocity Profiles in the Deep and Shallow Ocean written by Luiz Alberto Lopes de Souza and published by . This book was released on 2005 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Acoustic Inversion Methods for Exploration of the Shallow Water Environment written by Andrea Caiti and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, research on acoustic remote sensing of the ocean has evolved considerably, especially in studying complex physical and biological processes in shallow water environments. To review the state of the art, an international workshop was held at Carvoeiro, Portugal, in March 1999, bringing together leading international researchers in the field. In contrast to much of the recent theoretical work, emphasis was placed on the experimental validation of the techniques. This volume, based on presentations at this workshop, summarizes a range of diverse and innovative applications. The invited contributions explore the use of acoustics to measure bottom properties and morphology, as well as to probe buried objects within the sediment. Within the water column, sound is applied to imaging of oceanographic features such as currents and tides or monitoring of marine life. Another key theme is the use of sound to solve geometric inverse problems for precise tracking of undersea vehicles. Audience: This volume should be useful both to the novice seeking an introduction to the field and to advanced researchers interested in the latest developments in acoustic sensing of the ocean environment. The workshop was sponsored by the Fundação para a Ciêcia e a Tecnologia (Portuguese Foundation for Science and Technology).

Download or read book Full Field Inversion Methods in Ocean and Seismo Acoustics written by Orest Diachok and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in the power of inversion methods, the accuracy of acoustic field prediction codes, and the speed of digital computers have made the full field inversion of ocean and seismic parameters on a large scale a practical possibility. These methods exploit amplitude and phase information detected on hydrophone/geophone arrays, thereby extending traditional inversion schemes based on time of flight measurements. Full field inversion methods provide environmental information by minimising the mismatch between measured and predicted acoustic fields through a global search of possible environmental parameters. Full Field Inversion Methods in Ocean and Seismo-Acoustics is the formal record of a conference held in Italy in June 1994, sponsored by NATO SACLANT Undersea Research Centre. It includes papers by NATO specialists and others. Topics covered include: · speed and accuracy of acoustic field prediction codes · signal processing strategies · global inversion algorithms · search spaces of environmental parameters · environmental stochastic limitations · special purpose computer architectures · measurement geometries · source and receiving sensor technologies.

Download or read book A Modal WKB Inversion Method for Determining Sound Speed Profiles in the Ocean and Ocean Bottom written by Kevin D. Casey and published by . This book was released on 1988 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two approaches to determining the ocean sound profile using measured acoustic modal eigenvalues are examined. Both methods use measured eigenvalues and mode dependent assumed values of the WKB phase integral as input data and use the WKB phase integral as a starting point for relating the index of refraction to depth. Inversion method one is restricted to monotonic or symmetric sound speed profiles and requires a measurement of the sound speed at one depth to convert the index of refraction profile to a sound speed profile. Inversion method two assumes that the sound speed at the surface and the minimum sound speed in the profile are known and is applicable to monotonic profiles and to general single duct sound speed profiles. For asymmetric profiles, inversion method two gives the depth difference between two points of equal sound speed in the portion of the profile having two turning points, and in the remainder of the profile it gives sound speed versus depth directly. A numerical implementation of the methods is demonstrated using idealized ocean sound speed profiles numerical experiments used to test the performance of the inversions using noisy data. The two methods are used to determine the sediment sound speed profiles in two shallow water waveguide models, and inversion method one is used to find the sediment sound speed profile using data from an experiment performed in the Gulf of Mexico. Theses. (edc).

Download or read book Sound Propagation in the Sea written by Robert J. Urick and published by . This book was released on 1979 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Springer Handbook of Acoustics written by Thomas Rossing and published by Springer Science & Business Media. This book was released on 2007-06-21 with total page 1179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an unparalleled modern handbook reflecting the richly interdisciplinary nature of acoustics edited by an acknowledged master in the field. The handbook reviews the most important areas of the subject, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest research and applications are incorporated throughout, including computer recognition and synthesis of speech, physiological acoustics, diagnostic imaging and therapeutic applications and acoustical oceanography. An accompanying CD-ROM contains audio and video files.

Download or read book Measurement of the Ocean Acoustic Environment in Shallow Water Off the Coast of Fort Lauderdale written by Karl C. Focke and published by . This book was released on 1987 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acoustic Sensing Techniques for the Shallow Water Environment written by Andrea Caiti and published by Springer Science & Business Media. This book was released on 2006-09-21 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the collection of papers from the second workshop on Experimental Acoustic Inversion Techniques for Exploration of the Shallow Water Environment. Acoustic techniques provide the most effective means for remote sensing of ocean and sea floor processes, and for probing the structure beneath the sea floor. No other energy propagates as efficiently in the ocean: radio waves and visible light are severely limited in range because the ocean is a highly conductive medium. However, sound from breaking waves and coastal shipping can be heard throughout the ocean, and marine mammals communicate acoustically over basin scale distances. The papers in this book indicate a high level of research interest that has generated significant progress in development and application of experimental acoustic inversion techniques. The applications span a broad scope in geosciences, from geophysical, biological and even geochemical research. The list includes: estimation of geotechnical properties of sea bed materials; navigation and mapping of the sea floor; fisheries, aquaculture and sea bed habitat assessment; monitoring of marine mammals; sediment transport; and investigation of natural geohazards in marine sediments. Audience This book is primarily intended for physicists and engineers working in underwater acoustics and oceanic engineering. It will also be of interest to marine biologists, geophysicists and oceanographers as potential users of the methodologies and techniques described in the book contributions.

Download or read book Sound Speed Profile Inversion in the Ocean written by Linda Boden and published by . This book was released on 1985 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sound Propagation through the Stochastic Ocean written by John A. Colosi and published by Cambridge University Press. This book was released on 2016-06-20 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, key discoveries in the field of statistical ocean acoustics over the last 35 years are addressed with illustrations from ocean observations.

Download or read book Project Review on Geophysical and Ocean Sound Speed Profile Inversion written by N. Bleistein and published by . This book was released on 1984 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the status of the research projects on inverse problems at the Colorado School of Mines. We are engaged in two major projects in inverse problems: (I) inverse methods for reflector imaging; and (II) inverse methods for profile inversion in the ocean. In the first project we use 'high frequency' methods to invert backscatter (monostatic) observations. Our primary applications are to seabed mapping and seismic exploration although we have also implemented our method to image flaws in solids. Computer implementation of the current algorithm is discussed, and some indication of directions for extending the method is given. A unique feature of the second project is that the direction of variation of the sound speed profile (depth) is orthogonal to the direction of propagation (range). Again, high frequency methods are used and computer implementation is briefly discussed. Keywords include: velocity inversion Born Inversion, migration, stationary phase, singular function, and reflectivity function.

Download or read book Ambient Noise in the Sea written by Robert J. Urick and published by . This book was released on 1984 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variableness of the Sound Velocity Profile about the Mid Atlantic Ridge Axis written by Eli Joel Katz and published by . This book was released on 1969 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mediterranean Water, spreading across the North Atlantic Ocean, is shown to cause a disturbance to the acoustic medium in the vicinity of the Mid-Atlantic Ridge north of the Azores. In this region, the ridge crests are sufficiently shallow so as to impede the free movement of the intermediate waters. Warm and saline layers, nearly two hundred meters thick, were repeatedly observed in the lowering of continuous sampling sensors. These inversion layers are shown, by reconstruction, to result from local water movement across the ridge crest and are argued to be short lived and spatially confined. As a direct consequence the observed depth of the sound velocity minimum unpredictably fluctuated as much as five hundred meters within an area of two hundred miles square. The layers themselves result in secondary sound channels. The inversions of both temperature and salinity combine to produce inversions in the sound velocity profile of four meters per second, deep in the thermocline. (Author).

Download or read book Three dimensional Inversion Technique in Ocean Acoustics Using the Parabolic Equation Method written by Camilo Carlos Roa and published by . This book was released on 2017 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-dimensional parabolic equation (PE) and perturbation approach is used to invert for the depth- and range-dependent geoacoustic characteristics of the seabed. The model assumes that the sound speed profile is the superposition of a known range-independent profile and an unknown depth- and range-dependent perturbation. Using a Green's function approach, the total measured pressure field in the water column is decomposed into a background field, which is due to the range-independent profile, and a scattered field, which is due to the range-dependent perturbation. When the Born approximation is applied to the resulting integral equation, it can be solved for the range-dependent profile using linear inverse theory. Although the method is focused on inverting for the sound speed profile in the bottom, it can also invert for the sound speed profile in the water column. For simplicity, the sound speed profile in the water column was assumed to be known with a margin of error of ± 5 m/s. The range-dependent perturbation is added to the index of refraction squared n2(r), rather than the sound speed profile c(ro). The method is implemented in both Cartesian (x,y,z) and cylindrical (r,q,z) coordinates with the forward propagation of the field in x and r, respectively. Synthetic data are used to demonstrate the validity of the method [1]. Two inversion methods were combined, a Monte Carlo like algorithm, responsible for a starting approximation of the sound speed profile, and a steepest descent method, that fine-tuned the results. In simulations, the inversion algorithm is capable of inverting for the sound speed profile of a flat bottom. It was tested, for three different frequencies (50 Hz, 75 Hz, and 100 Hz), in a Pekeris waveguide, a range-independent layered medium, and a range-dependent medium, with errors in the inverted sound speed profile of less than 3%. Keywords: Three-dimensional parabolic equation method, geoacoustic inversion, range-dependent sound speed profile, linear inversion, Born approximation, Green's functions.

Download or read book Inverting for the Ocean Sound Speed Structure written by Michael Gregory Brown and published by . This book was released on 1982 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Progress in Underwater Acoustics written by Harold Merklinger and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 815 pages. Available in PDF, EPUB and Kindle. Book excerpt: IMAGE TRACKS AT HALIFAX by L.B. Felsen All living kind much effort spend Some model modes, some model rays, To cope with their environment Some feel that spectra all portrays. Some use their eyes, some use their nose Then there are those who with despatch, To sense where other things repose. Take refuge in the ocean wedge. For one group, nothing's more profound Than to explore the world with sound. If things get messy, randomize. These audio diagnosticians What's partly smooth, determinize. You ponder, is it this or that? Go by the name of acousticians. And wish you were a lowly bat They regularly meet to check Whether their sonogram's on track. The meeting's hosts did treat us well. With images stored in their packs, They let the climate cast its spell. This year they came to Halifax. No weath'ry hope was placed in vain. There they combined with ocean types We were exposed to wind and rain, And each could hear the other's gripes. We glimpsed blue sky through clouds dispersed. A meeting naturally does start But rainy sequence was reversed: Reviewing present state of art. The ocean types would like it wet What we found out is where it's at: Yet they got stuck with sun instead. We cannot hope to match the bat Each confrence has the same refrain: Computer printouts by the reams It has been fun to meet again.