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Journal ArticleDOI

Reduced rank models for travel time estimation of low order mode pulses.

04 Oct 2013-Journal of the Acoustical Society of America (Acoustical Society of America)-Vol. 134, Iss: 4, pp 3332-3346
TL;DR: A reduced-rank EOF model is used to construct a travel time estimator based on the Matched Subspace Detector (MSD) and analysis of simulation and experimental data show that the MSDs are more robust to IW scattering than peak picking.
Abstract: Mode travel time estimation in the presence of internal waves (IWs) is a challenging problem. IWs perturb the sound speed, which results in travel time wander and mode scattering. A standard approach to travel time estimation is to pulse compress the broadband signal, pick the peak of the compressed time series, and average the peak time over multiple receptions to reduce variance. The peak-picking approach implicitly assumes there is a single strong arrival and does not perform well when there are multiple arrivals due to scattering. This article presents a statistical model for the scattered mode arrivals and uses the model to design improved travel time estimators. The model is based on an Empirical Orthogonal Function (EOF) analysis of the mode time series. Range-dependent simulations and data from the Long-range Ocean Acoustic Propagation Experiment (LOAPEX) indicate that the modes are represented by a small number of EOFs. The reduced-rank EOF model is used to construct a travel time estimator based on the Matched Subspace Detector (MSD). Analysis of simulation and experimental data show that the MSDs are more robust to IW scattering than peak picking. The simulation analysis also highlights how IWs affect the mode excitation by the source.

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Citations
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01 Jul 1976
TL;DR: Electrical and computer engineering ece courses ece 257a multiuser communication systems 4 congestion control convex programming and dual controller fair end end rate allocation max min fair vs proportional, electrical systems engineering washington university.
Abstract: electrical and computer engineering ece courses ece 257a multiuser communication systems 4 congestion control convex programming and dual controller fair end end rate allocation max min fair vs proportional, electrical systems engineering washington university arye nehorai eugene and martha lohman professor of electrical engineering phd stanford university signal processing imaging biomedicine communications, ieee transactions on aerospace and electronic systems ieee transactions on aerospace and electronic systems focuses on the organization design development integration and operation of complex systems for space air, department of electrical engineering and computer science h kumar wickramsinghe department chair 2213 engineering hall 949 824 4821 http www eng uci edu dept eecs overview electrical engineering and computer science is, download electrical and electronics engineering ebooks syst mes temps discret commande num rique des proc d s pdf 499 ko terminology and symbols in control engineering pdf 326 ko the best of thomas, publications stream wise list iit kanpur papers published in journals in 2016 dutta s patchaikani p k behera l near optimal controller for nonlinear continuous time systems with unknown dynamics, resolve a doi name type or paste a doi name into the text box click go your browser will take you to a web page url associated with that doi name send questions or comments to doi, peer reviewed journal ijera com international journal of engineering research and applications ijera is an open access online peer reviewed international journal that publishes research, dod sbir 2016 2 sbir gov note the solicitations and topics listed on this site are copies from the various sbir agency solicitations and are not necessarily the latest and most up, an english japanese dictionary of electrical engineering c 2952 9 691 c band c c contact c c maccs centre for mathematical modelling and computer simulation, the of and to a in that is was he for it with as his on be most common text click on the icon to return to www berro com and to enjoy and benefit the of and to a in that is was he for it with as his on be at by i this had

590 citations

Journal ArticleDOI
TL;DR: Noise in that band using data from the SPICEX experiment, which took place in the North Pacific in 2004-2005, is analyzed and the seasonal trends in noise over the year-long time series of the measurements are described.
Abstract: Shipping noise and wind are the dominant sources of ocean noise in the frequency band between 20 and 500 Hz. This paper analyzes noise in that band using data from the SPICEX experiment, which took place in the North Pacific in 2004–2005, and compares the results with other North Pacific experiments. SPICEX included vertical arrays with sensors above and below the surface conjugate depth, facilitating an analysis of the depth dependence of ambient noise. The paper includes several key results. First, the 2004–05 noise levels at 50 Hz measured in SPICEX had not increased relative to levels measured by Morris [(1978). J. Acoust. Soc. Am. 64, 581–590] at a nearby North Pacific site three decades earlier, but rather were comparable to those levels. Second, at 50 Hz the noise below the conjugate depth decreases at a rate of −9.9 dB/km, which is similar to the rate measured by Morris and much less than the rate measured by Gaul, Knobles, Shooter, and Wittenborn [(2007). IEEE J. Ocean. Eng. 32, 497–512] for the ...

17 citations

ReportDOI
30 Sep 2012
TL;DR: In this article, the authors used spectral analysis to characterize the ambient noise in the Philippine Sea (PhilSea) data set using spectral analysis and to compare the results to those for other deep water data sets.
Abstract: : The broad goals of this research are to characterize deep ocean noise processes, to analyze mode propagation in the deep water channel, and to implement acoustic tomography using mode signals. The primary focus of this project is the analysis of data from the Philippine Sea (PhilSea) experiments in 2009-2011. Data from previous ONR-sponsored deep water experiments is also being analyzed. The specific objectives of the project are: 1) to characterize the ambient noise in the PhilSea data set using spectral analysis and to compare the results to those for other deep water data sets; 2) to analyze the acoustic modes in the ambient noise and moored source data sets acquired in the PhilSea experiments; 3) to implement tomographic inversions using mode signals from the PhilSea experiments.

1 citations

ReportDOI
30 Sep 2012
TL;DR: The North Pacific Acoustic Laboratory (NPAL) program as mentioned in this paper is intended to improve our understanding of the basic physics of low-frequency, broadband propagation in deep water, including the effects of oceanographic variability on signal stability and coherence.
Abstract: : The North Pacific Acoustic Laboratory (NPAL) program is intended to improve our understanding of (i) the basic physics of low-frequency, broadband propagation in deep water, including the effects of oceanographic variability on signal stability and coherence, (ii) the structure of the ambient noise field in deep water at low frequencies, and (iii) the extent to which acoustic methods, together with other measurements and coupled with ocean modeling, can yield estimates of the time-evolving ocean state useful for acoustic predictions. The goal is to determine the fundamental limits to signal processing in deep water imposed by ocean processes, enabling advanced signal processing techniques to capitalize on the three-dimensional character of the sound and noise fields.

1 citations

Journal ArticleDOI
TL;DR: In this paper , the authors used the modes of the waveguide in a transport theory application to predict the effects of internal wave induced scattering on acoustic pulses, and compared the performance of the two models.
Abstract: There are currently no models to fully predict the effects of internal wave induced scattering on acoustic pulses. Existing models, which predict time domain statistics, either use the ray-based path integral method or Monte Carlo type simulations. The path integral method fails to accurately predict all of the effects of scattering. The Monte Carlo methods base the statistics on ensemble averages and are not physics-based models. This paper overcomes these limitations by using the modes of the waveguide in a transport theory application. The transport theory equations have, thus far, been used only to explain diffusion of mode intensities and decorrelation due to internal waves at individual frequencies. This paper extends the current narrowband application predict mode correlations across different frequencies and, from that, the broadband time-front, time wander, travel time bias, and the amount of spread in intensity across time and depth. To validate these predictions, this paper uses separate parabolic equation simulations. The comparisons between the two are good, suggesting a success for the mode-based transport theory approach.
References
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Book
01 May 1986
TL;DR: In this article, the authors present a graphical representation of data using Principal Component Analysis (PCA) for time series and other non-independent data, as well as a generalization and adaptation of principal component analysis.
Abstract: Introduction * Properties of Population Principal Components * Properties of Sample Principal Components * Interpreting Principal Components: Examples * Graphical Representation of Data Using Principal Components * Choosing a Subset of Principal Components or Variables * Principal Component Analysis and Factor Analysis * Principal Components in Regression Analysis * Principal Components Used with Other Multivariate Techniques * Outlier Detection, Influential Observations and Robust Estimation * Rotation and Interpretation of Principal Components * Principal Component Analysis for Time Series and Other Non-Independent Data * Principal Component Analysis for Special Types of Data * Generalizations and Adaptations of Principal Component Analysis

17,446 citations

Journal ArticleDOI
TL;DR: In this article, the authors present state-of-the-art numerical techniques to solve the wave equation in heterogeneous fluid-solid media and present a comprehensive and modern introduction to computational ocean acoustics accessible to students.
Abstract: Senior level/graduate level text/reference presenting state-of-the- art numerical techniques to solve the wave equation in heterogeneous fluid-solid media. Numerical models have become standard research tools in acoustic laboratories, and thus computational acoustics is becoming an increasingly important branch of ocean acoustic science. The first edition of this successful book, written by the recognized leaders of the field, was the first to present a comprehensive and modern introduction to computational ocean acoustics accessible to students. This revision, with 100 additional pages, completely updates the material in the first edition and includes new models based on current research. It includes problems and solutions in every chapter, making the book more useful in teaching (the first edition had a separate solutions manual). The book is intended for graduate and advanced undergraduate students of acoustics, geology and geophysics, applied mathematics, ocean engineering or as a reference in computational methods courses, as well as professionals in these fields, particularly those working in government (especially Navy) and industry labs engaged in the development or use of propagating models.

1,344 citations

Journal ArticleDOI
01 Jan 1985

992 citations

Journal ArticleDOI
TL;DR: The generalized likelihood ratio (GLR) is the uniformly most powerful invariant detector and the utility of this finding is illustrated by solving a number of problems for detecting subspace signals in subspace interference and broadband noise.
Abstract: We formulate a general class of problems for detecting subspace signals in subspace interference and broadband noise. We derive the generalized likelihood ratio (GLR) for each problem in the class. We then establish the invariances for the GLR and argue that these are the natural invariances for the problem. In each case, the GLR is a maximal invariant statistic, and the distribution of the maximal invariant statistic is monotone. This means that the GLR test (GLRT) is the uniformly most powerful invariant detector. We illustrate the utility of this finding by solving a number of problems for detecting subspace signals in subspace interference and broadband noise. In each case we give the distribution for the detector and compute performance curves. >

959 citations


"Reduced rank models for travel time..." refers methods in this paper

  • ...This paper adapted the MSD approach of Scharf and Friedlander (1994) to estimate the arrival time of mode pulses that lie within a known subspace....

    [...]

  • ...Download to IP: 203.199.213.66 On: Wed, 04 Mar 2015 06:59:54 Given a low rank model for the modes, this paper develops a new travel time estimator based on the Matched Subspace Detector (MSD) framework proposed by Scharf and Friedlander (1994)....

    [...]

  • ...The MSD approach is further described in articles by Scharf and Friedlander (1994), and McWhorter and Scharf (2003)....

    [...]

Journal ArticleDOI
TL;DR: In this article, a revised model for the distribution of internal wave energy in wave number frequency space is presented, guided by the following measurements: moored spectra and moored coherences for horizontal and vertical separations.
Abstract: We present a revised model for the distribution of internal wave energy in wave number frequency space. The model is empirical, guided by the following measurements: moored spectra and moored coherences for horizontal and vertical separations (MS, MHC, MVC as functions of frequency), towed spectra and towed vertical and time-lagged coherences (TS, TVC, TLC as functions of horizontal wave number), and dropped spectra and dropped horizontal and lagged coherences (DS, DHC, DLC as functions of vertical wave number). Measurements are available for all but TLC and DHC. There is some indication of universality, suggesting perhaps a saturation limit.

860 citations


"Reduced rank models for travel time..." refers methods in this paper

  • ...Colosi and Brown’s method is based on the Garrett–Munk (GM) spectrum (Garrett and Munk, 1972, 1975)....

    [...]