Development of a new British Geologcial Survey(BGS) Map Series: Seabed Geomorphology

NASA Astrophysics Data System (ADS)

Dove, Dayton

2015-04-01

BGS scientists are developing a new offshore map series, Seabed Geomorphology (1:50k), to join the existing 1:250k 'Sea Bed Sediments', 'Quaternary Geology', and 'Solid Geology' map series. The increasing availability of extensive high-resolution swath bathymetry data (e.g. MCA's Civil Hydrography Programme) provides an unprecedented opportunity to characterize the processes which formed, and actively govern the physical seabed environment. Mapping seabed geomorphology is an effective means to describe individual, or groups of features whose form and other physical attributes (e.g. symmetry) may be used to distinguish feature origin. Swath bathymetry also provides added and renewed value to other data types (e.g. grab samples, legacy seismic data). In such cases the geomorphic evidence may be expanded to make inferences on the evolution of seabed features as well as their association with the underlying geology and other environmental variables/events over multiple timescales. Classifying seabed geomorphology is not particularly innovative or groundbreaking. Terrestrial geomorphology is of course a well established field of science, and within the marine environment for example, mapping submarine glacial landforms has probably become the most reliable method to reconstruct the extent and dynamics of past ice-sheets. What is novel here, and we believe useful/necessary for a survey organization, is to standardise the geomorphological classification scheme such that it is applicable to multiple and diverse environments. The classification scheme should be sufficiently detailed and interpretive to be informative, but not so detailed that we over-interpret or become mired in disputed feature designations or definitions. We plan to present the maps at 1:50k scale with the intention that these maps will be 'enabling' resources for research, educational, commercial, and policy purposes, much like the existing 1:250k map series. We welcome feedback on the structure and

Analysis of wind-driven ambient noise in a shallow water environment with a sandy seabed.

PubMed

Knobles, D P; Joshi, S M; Gaul, R D; Graber, H C; Williams, N J

2008-09-01

On the New Jersey continental shelf ambient sound levels were recorded during tropical storm Ernesto that produced wind speeds up to 40 knots in early September 2006. The seabed at the position of the acoustic measurements can be approximately described as coarse sand. Differences between the ambient noise levels for the New Jersey shelf measurements and deep water reference measurements are modeled using both normal mode and ray methods. The analysis is consistent with a nonlinear frequency dependent seabed attenuation for the New Jersey site.

Remote sensing of deep hermatypic coral reefs in Puerto Rico and the U.S. Virgin Islands using the Seabed autonomous underwater vehicle

NASA Astrophysics Data System (ADS)

Armstrong, Roy A.; Singh, Hanumant

2006-09-01

Optical imaging of coral reefs and other benthic communities present below one attenuation depth, the limit of effective airborne and satellite remote sensing, requires the use of in situ platforms such as autonomous underwater vehicles (AUVs). The Seabed AUV, which was designed for high-resolution underwater optical and acoustic imaging, was used to characterize several deep insular shelf reefs of Puerto Rico and the US Virgin Islands using digital imagery. The digital photo transects obtained by the Seabed AUV provided quantitative data on living coral, sponge, gorgonian, and macroalgal cover as well as coral species richness and diversity. Rugosity, an index of structural complexity, was derived from the pencil-beam acoustic data. The AUV benthic assessments could provide the required information for selecting unique areas of high coral cover, biodiversity and structural complexity for habitat protection and ecosystem-based management. Data from Seabed sensors and related imaging technologies are being used to conduct multi-beam sonar surveys, 3-D image reconstruction from a single camera, photo mosaicking, image based navigation, and multi-sensor fusion of acoustic and optical data.

Detection and Classification of Whale Acoustic Signals

NASA Astrophysics Data System (ADS)

Xian, Yin

This dissertation focuses on two vital challenges in relation to whale acoustic signals: detection and classification. In detection, we evaluated the influence of the uncertain ocean environment on the spectrogram-based detector, and derived the likelihood ratio of the proposed Short Time Fourier Transform detector. Experimental results showed that the proposed detector outperforms detectors based on the spectrogram. The proposed detector is more sensitive to environmental changes because it includes phase information. In classification, our focus is on finding a robust and sparse representation of whale vocalizations. Because whale vocalizations can be modeled as polynomial phase signals, we can represent the whale calls by their polynomial phase coefficients. In this dissertation, we used the Weyl transform to capture chirp rate information, and used a two dimensional feature set to represent whale vocalizations globally. Experimental results showed that our Weyl feature set outperforms chirplet coefficients and MFCC (Mel Frequency Cepstral Coefficients) when applied to our collected data. Since whale vocalizations can be represented by polynomial phase coefficients, it is plausible that the signals lie on a manifold parameterized by these coefficients. We also studied the intrinsic structure of high dimensional whale data by exploiting its geometry. Experimental results showed that nonlinear mappings such as Laplacian Eigenmap and ISOMAP outperform linear mappings such as PCA and MDS, suggesting that the whale acoustic data is nonlinear. We also explored deep learning algorithms on whale acoustic data. We built each layer as convolutions with either a PCA filter bank (PCANet) or a DCT filter bank (DCTNet). With the DCT filter bank, each layer has different a time-frequency scale representation, and from this, one can extract different physical information. Experimental results showed that our PCANet and DCTNet achieve high classification rate on the whale

Efficient sensor network vehicle classification using peak harmonics of acoustic emissions

NASA Astrophysics Data System (ADS)

William, Peter E.; Hoffman, Michael W.

2008-04-01

An application is proposed for detection and classification of battlefield ground vehicles using the emitted acoustic signal captured at individual sensor nodes of an ad hoc Wireless Sensor Network (WSN). We make use of the harmonic characteristics of the acoustic emissions of battlefield vehicles, in reducing both the computations carried on the sensor node and the transmitted data to the fusion center for reliable and effcient classification of targets. Previous approaches focus on the lower frequency band of the acoustic emissions up to 500Hz; however, we show in the proposed application how effcient discrimination between battlefield vehicles is performed using features extracted from higher frequency bands (50 - 1500Hz). The application shows that selective time domain acoustic features surpass equivalent spectral features. Collaborative signal processing is utilized, such that estimation of certain signal model parameters is carried by the sensor node, in order to reduce the communication between the sensor node and the fusion center, while the remaining model parameters are estimated at the fusion center. The transmitted data from the sensor node to the fusion center ranges from 1 ~ 5% of the sampled acoustic signal at the node. A variety of classification schemes were examined, such as maximum likelihood, vector quantization and artificial neural networks. Evaluation of the proposed application, through processing of an acoustic data set with comparison to previous results, shows that the improvement is not only in the number of computations but also in the detection and false alarm rate as well.

Acoustic classification of zooplankton

NASA Astrophysics Data System (ADS)

Martin Traykovski, Linda V.

1998-11-01

Work on the forward problem in zooplankton bioacoustics has resulted in the identification of three categories of acoustic scatterers: elastic-shelled (e.g. pteropods), fluid-like (e.g. euphausiids), and gas-bearing (e.g. siphonophores). The relationship between backscattered energy and animal biomass has been shown to vary by a factor of ~19,000 across these categories, so that to make accurate estimates of zooplankton biomass from acoustic backscatter measurements of the ocean, the acoustic characteristics of the species of interest must be well-understood. This thesis describes the development of both feature based and model based classification techniques to invert broadband acoustic echoes from individual zooplankton for scatterer type, as well as for particular parameters such as animal orientation. The feature based Empirical Orthogonal Function Classifier (EOFC) discriminates scatterer types by identifying characteristic modes of variability in the echo spectra, exploiting only the inherent characteristic structure of the acoustic signatures. The model based Model Parameterisation Classifier (MPC) classifies based on correlation of observed echo spectra with simplified parameterisations of theoretical scattering models for the three classes. The Covariance Mean Variance Classifiers (CMVC) are a set of advanced model based techniques which exploit the full complexity of the theoretical models by searching the entire physical model parameter space without employing simplifying parameterisations. Three different CMVC algorithms were developed: the Integrated Score Classifier (ISC), the Pairwise Score Classifier (PSC) and the Bayesian Probability Classifier (BPC); these classifiers assign observations to a class based on similarities in covariance, mean, and variance, while accounting for model ambiguity and validity. These feature based and model based inversion techniques were successfully applied to several thousand echoes acquired from broadband (~350 k

Extraction of Seabed/Subsurface Features in a Potential CO2 Sequestration Site in the Southern Baltic Sea, Using Wavelet Transform of High-resolution Sub-Bottom Profiler Data

NASA Astrophysics Data System (ADS)

Tegowski, J.; Zajfert, G.

2014-12-01

Carbon Capture & Storage (CCS) efficiently prevents the release of anthropogenic CO2 into the atmosphere. We investigate a potential site in the Polish Sector of the Baltic Sea (B3 field site), consisting in a depleted oil and gas reservoir. An area ca. 30 x 8 km was surveyed along 138 acoustic transects, realised from R/V St. Barbara in 2012 and combining multibeam echosounder, sidescan sonar and sub-bottom profiler. Preparation of CCS sites requires accurate knowledge of the subsurface structure of the seafloor, in particular deposit compactness. Gas leaks in the water column were monitored, along with the structure of upper sediment layers. Our analyses show the shallow sub-seabed is layered, and quantified the spatial distribution of gas diffusion chimneys and seabed effusion craters. Remote detection of gas-containing surface sediments can be rather complex if bubbles are not emitted directly into the overlying water and thus detectable acoustically. The heterogeneity of gassy sediments makes conventional bottom sampling methods inefficient. Therefore, we propose a new approach to identification, mapping, and monitoring of potentially gassy surface sediments, based on wavelet analysis of echo signal envelopes of a chirp sub-bottom profiler (EdgeTech SB-0512). Each echo envelope was subjected to wavelet transformation, whose coefficients were used to calculate wavelet energies. The set of echo envelope parameters was input to fuzzy logic and c-means algorithms. The resulting classification highlights seafloor areas with different subsurface morphological features, which can indicate gassy sediments. This work has been conducted under EC FP7-CP-IP project No. 265847: Sub-seabed CO2 Storage: Impact on Marine Ecosystems (ECO2).

Acoustic transient classification with a template correlation processor.

PubMed

Edwards, R T

1999-10-01

I present an architecture for acoustic pattern classification using trinary-trinary template correlation. In spite of its computational simplicity, the algorithm and architecture represent a method which greatly reduces bandwidth of the input, storage requirements of the classifier memory, and power consumption of the system without compromising classification accuracy. The linear system should be amenable to training using recently-developed methods such as Independent Component Analysis (ICA), and we predict that behavior will be qualitatively similar to that of structures in the auditory cortex.

Selecting Optimal Random Forest Predictive Models: A Case Study on Predicting the Spatial Distribution of Seabed Hardness

PubMed Central

Li, Jin; Tran, Maggie; Siwabessy, Justy

2016-01-01

Spatially continuous predictions of seabed hardness are important baseline environmental information for sustainable management of Australia’s marine jurisdiction. Seabed hardness is often inferred from multibeam backscatter data with unknown accuracy and can be inferred from underwater video footage at limited locations. In this study, we classified the seabed into four classes based on two new seabed hardness classification schemes (i.e., hard90 and hard70). We developed optimal predictive models to predict seabed hardness using random forest (RF) based on the point data of hardness classes and spatially continuous multibeam data. Five feature selection (FS) methods that are variable importance (VI), averaged variable importance (AVI), knowledge informed AVI (KIAVI), Boruta and regularized RF (RRF) were tested based on predictive accuracy. Effects of highly correlated, important and unimportant predictors on the accuracy of RF predictive models were examined. Finally, spatial predictions generated using the most accurate models were visually examined and analysed. This study confirmed that: 1) hard90 and hard70 are effective seabed hardness classification schemes; 2) seabed hardness of four classes can be predicted with a high degree of accuracy; 3) the typical approach used to pre-select predictive variables by excluding highly correlated variables needs to be re-examined; 4) the identification of the important and unimportant predictors provides useful guidelines for further improving predictive models; 5) FS methods select the most accurate predictive model(s) instead of the most parsimonious ones, and AVI and Boruta are recommended for future studies; and 6) RF is an effective modelling method with high predictive accuracy for multi-level categorical data and can be applied to ‘small p and large n’ problems in environmental sciences. Additionally, automated computational programs for AVI need to be developed to increase its computational efficiency and

Selecting Optimal Random Forest Predictive Models: A Case Study on Predicting the Spatial Distribution of Seabed Hardness.

PubMed

Li, Jin; Tran, Maggie; Siwabessy, Justy

2016-01-01

Spatially continuous predictions of seabed hardness are important baseline environmental information for sustainable management of Australia's marine jurisdiction. Seabed hardness is often inferred from multibeam backscatter data with unknown accuracy and can be inferred from underwater video footage at limited locations. In this study, we classified the seabed into four classes based on two new seabed hardness classification schemes (i.e., hard90 and hard70). We developed optimal predictive models to predict seabed hardness using random forest (RF) based on the point data of hardness classes and spatially continuous multibeam data. Five feature selection (FS) methods that are variable importance (VI), averaged variable importance (AVI), knowledge informed AVI (KIAVI), Boruta and regularized RF (RRF) were tested based on predictive accuracy. Effects of highly correlated, important and unimportant predictors on the accuracy of RF predictive models were examined. Finally, spatial predictions generated using the most accurate models were visually examined and analysed. This study confirmed that: 1) hard90 and hard70 are effective seabed hardness classification schemes; 2) seabed hardness of four classes can be predicted with a high degree of accuracy; 3) the typical approach used to pre-select predictive variables by excluding highly correlated variables needs to be re-examined; 4) the identification of the important and unimportant predictors provides useful guidelines for further improving predictive models; 5) FS methods select the most accurate predictive model(s) instead of the most parsimonious ones, and AVI and Boruta are recommended for future studies; and 6) RF is an effective modelling method with high predictive accuracy for multi-level categorical data and can be applied to 'small p and large n' problems in environmental sciences. Additionally, automated computational programs for AVI need to be developed to increase its computational efficiency and

High temporal resolution of extreme rainfall rate variability and the acoustic classification of rainfall

NASA Astrophysics Data System (ADS)

Nystuen, Jeffrey A.; Amitai, Eyal

2003-04-01

The underwater sound generated by raindrop splashes on a water surface is loud and unique allowing detection, classification and quantification of rainfall. One of the advantages of the acoustic measurement is that the listening area, an effective catchment area, is proportional to the depth of the hydrophone and can be orders of magnitude greater than other in situ rain gauges. This feature allows high temporal resolution of the rainfall measurement. A series of rain events with extremely high rainfall rates, over 100 mm/hr, is examined acoustically. Rapid onset and cessation of rainfall intensity are detected within the convective cells of these storms with maximum 5-s resolution values exceeding 1000 mm/hr. The probability distribution functions (pdf) for rainfall rate occurrence and water volume using the longer temporal resolutions typical of other instruments do not include these extreme values. The variance of sound intensity within different acoustic frequency bands can be used as an aid to classify rainfall type. Objective acoustic classification algorithms are proposed. Within each rainfall classification the relationship between sound intensity and rainfall rate is nearly linear. The reflectivity factor, Z, also has a linear relationship with rainfall rate, R, for each rainfall classification.

Statistical inference of seabed sound-speed structure in the Gulf of Oman Basin.

PubMed

Sagers, Jason D; Knobles, David P

2014-06-01

Addressed is the statistical inference of the sound-speed depth profile of a thick soft seabed from broadband sound propagation data recorded in the Gulf of Oman Basin in 1977. The acoustic data are in the form of time series signals recorded on a sparse vertical line array and generated by explosive sources deployed along a 280 km track. The acoustic data offer a unique opportunity to study a deep-water bottom-limited thickly sedimented environment because of the large number of time series measurements, very low seabed attenuation, and auxiliary measurements. A maximum entropy method is employed to obtain a conditional posterior probability distribution (PPD) for the sound-speed ratio and the near-surface sound-speed gradient. The multiple data samples allow for a determination of the average error constraint value required to uniquely specify the PPD for each data sample. Two complicating features of the statistical inference study are addressed: (1) the need to develop an error function that can both utilize the measured multipath arrival structure and mitigate the effects of data errors and (2) the effect of small bathymetric slopes on the structure of the bottom interacting arrivals.

Acoustic target detection and classification using neural networks

NASA Technical Reports Server (NTRS)

Robertson, James A.; Conlon, Mark

1993-01-01

A neural network approach to the classification of acoustic emissions of ground vehicles and helicopters is demonstrated. Data collected during the Joint Acoustic Propagation Experiment conducted in July of l991 at White Sands Missile Range, New Mexico was used to train a classifier to distinguish between the spectrums of a UH-1, M60, M1 and M114. An output node was also included that would recognize background (i.e. no target) data. Analysis revealed specific hidden nodes responding to the features input into the classifier. Initial results using the neural network were encouraging with high correct identification rates accompanied by high levels of confidence.

Mapping the seabed and habitats in National Marine Sanctuaries - Examples from the East, Gulf and West Coasts

USGS Publications Warehouse

Valentine, Page C.; Cochrane, Guy R.; Scanlon, Kathryn M.

2003-01-01

The National Marine Sanctuary System requires seabed and habitat maps to serve as a basis for managing sanctuary resources and for conducting research. NOAA, the agency that manages the sanctuaries, and the USGS have conducted mapping projects in three sanctuaries (Stellwagen Bank NMS, Flower Garden Banks NMS, and Channel Islands NMS) with an emphasis on collaboration of geologists and biologists from the two agencies and from academic institutions. Mapping of seabed habitats is a developing field that requires the integration of geologic and biologic studies and the use of swath imaging techniques such as multibeam and sidescan sonar. Major products of swath mapping are shaded-relief topographic imagery which shows seabed features in great detail, and backscatter imagery which provides an indication of the types of materials that constitute the seabed. Sea floor images provide an excellent basis for conducting the groundtruthing studies (using video, photo, and sampling techniques) that are required to collect the data necessary for making meaningful interpretative maps of the seabed. The compilation of interpretive maps showing seabed environments and habitats also requires the development of a sea floor classification system that will be a basis for comparing, managing, and researching characteristic areas of the seabed. Seabed maps of the sanctuaries are proving useful for management and research decisions that address commercial and recreational fishing, habitat disturbance, engineering projects, tourism, and cultural resources.

Highly dynamic biological seabed alterations revealed by side scan sonar tracking of Lanice conchilega beds offshore the island of Sylt (German Bight)

NASA Astrophysics Data System (ADS)

Heinrich, C.; Feldens, P.; Schwarzer, K.

2017-06-01

Hydroacoustic surveys are common tools for habitat investigation and monitoring that aid in the realisation of the aims of the EU Marine Directives. However, the creation of habitat maps is difficult, especially when benthic organisms densely populate the seafloor. This study assesses the sensitivity of entropy and homogeneity image texture parameters derived from backscatter strength data to benthic habitats dominated by the tubeworm Lanice conchilega. Side scan sonar backscatter surveys were carried out in 2010 and 2011 in the German Bight (southern North Sea) at two sites approx. 20 km offshore of the island of Sylt. Abiotic and biotic seabed facies, such as sorted bedforms, areas of fine to medium sand and L. conchilega beds with different tube densities, were identified and characterised based on manual expert analysis and image texture analysis. Ground truthing was performed by grab sampling and underwater video observations. Compared to the manual expert analysis, the k- means classification of image textures proves to be a semi-automated method to investigate small-scale differences in a biologically altered seabed from backscatter data. The texture parameters entropy and homogeneity appear linearly interrelated with tube density, the former positively and the latter negatively. Reinvestigation of one site after 1 year showed an extensive change in the distribution of the L. conchilega-altered seabed. Such marked annual fluctuations in L. conchilega tube cover demonstrate the need for dense time series and high spatial coverage to meaningfully monitor ecological patterns on the seafloor with acoustic backscatter methods in the study region and similar settings worldwide, particularly because the sand mason plays a pivotal role in promoting biodiversity. In this context, image texture analysis provides a cost-effective and reproducible method to track biologically altered seabeds from side scan sonar backscatter signatures.

Perceptual and Acoustic Reliability Estimates for the Speech Disorders Classification System (SDCS)

ERIC Educational Resources Information Center

Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.

2010-01-01

A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speaker's speech, prosody, and voice. The present paper provides reliability estimates for…

Classification of underwater targets from autonomous underwater vehicle sampled bistatic acoustic scattered fields.

PubMed

Fischell, Erin M; Schmidt, Henrik

2015-12-01

One of the long term goals of autonomous underwater vehicle (AUV) minehunting is to have multiple inexpensive AUVs in a harbor autonomously classify hazards. Existing acoustic methods for target classification using AUV-based sensing, such as sidescan and synthetic aperture sonar, require an expensive payload on each outfitted vehicle and post-processing and/or image interpretation. A vehicle payload and machine learning classification methodology using bistatic angle dependence of target scattering amplitudes between a fixed acoustic source and target has been developed for onboard, fully autonomous classification with lower cost-per-vehicle. To achieve the high-quality, densely sampled three-dimensional (3D) bistatic scattering data required by this research, vehicle sampling behaviors and an acoustic payload for precision timed data acquisition with a 16 element nose array were demonstrated. 3D bistatic scattered field data were collected by an AUV around spherical and cylindrical targets insonified by a 7-9 kHz fixed source. The collected data were compared to simulated scattering models. Classification and confidence estimation were shown for the sphere versus cylinder case on the resulting real and simulated bistatic amplitude data. The final models were used for classification of simulated targets in real time in the LAMSS MOOS-IvP simulation package [M. Benjamin, H. Schmidt, P. Newman, and J. Leonard, J. Field Rob. 27, 834-875 (2010)].

Acoustic Event Detection and Classification

NASA Astrophysics Data System (ADS)

Temko, Andrey; Nadeu, Climent; Macho, Dušan; Malkin, Robert; Zieger, Christian; Omologo, Maurizio

The human activity that takes place in meeting rooms or classrooms is reflected in a rich variety of acoustic events (AE), produced either by the human body or by objects handled by humans, so the determination of both the identity of sounds and their position in time may help to detect and describe that human activity. Indeed, speech is usually the most informative sound, but other kinds of AEs may also carry useful information, for example, clapping or laughing inside a speech, a strong yawn in the middle of a lecture, a chair moving or a door slam when the meeting has just started. Additionally, detection and classification of sounds other than speech may be useful to enhance the robustness of speech technologies like automatic speech recognition.

Acoustic mapping and classification of benthic habitat using unsupervised learning in artificial reef water

NASA Astrophysics Data System (ADS)

Li, Dong; Tang, Cheng; Xia, Chunlei; Zhang, Hua

2017-02-01

Artificial reefs (ARs) are effective means to maintain fishery resources and to restore ecological environment in coastal waters. ARs have been widely constructed along the Chinese coast. However, understanding of benthic habitats in the vicinity of ARs is limited, hindering effective fisheries and aquacultural management. Multibeam echosounder (MBES) is an advanced acoustic instrument capable of efficiently generating large-scale maps of benthic environments at fine resolutions. The objective of this study is to develop a technical approach to characterize, classify, and map shallow coastal areas with ARs using an MBES. An automated classification method is designed and tested to process bathymetric and backscatter data from MBES and transform the variables into simple, easily visualized maps. To reduce the redundancy in acoustic variables, a principal component analysis (PCA) is used to condense the highly collinear dataset. An acoustic benthic map of bottom sediments is classified using an iterative self-organizing data analysis technique (ISODATA). The approach is tested with MBES surveys in a 1.15 km2 fish farm with a high density of ARs off the Yantai coast in northern China. Using this method, 3 basic benthic habitats (sandy bottom, muddy sediments, and ARs) are distinguished. The results of the classification are validated using sediment samples and underwater surveys. Our study shows that the use of MBES is an effective method for acoustic mapping and classification of ARs.

Artillery/mortar type classification based on detected acoustic transients

NASA Astrophysics Data System (ADS)

Morcos, Amir; Grasing, David; Desai, Sachi

2008-04-01

Feature extraction methods based on the statistical analysis of the change in event pressure levels over a period and the level of ambient pressure excitation facilitate the development of a robust classification algorithm. The features reliably discriminates mortar and artillery variants via acoustic signals produced during the launch events. Utilizing acoustic sensors to exploit the sound waveform generated from the blast for the identification of mortar and artillery variants as type A, etcetera through analysis of the waveform. Distinct characteristics arise within the different mortar/artillery variants because varying HE mortar payloads and related charges emphasize varying size events at launch. The waveform holds various harmonic properties distinct to a given mortar/artillery variant that through advanced signal processing and data mining techniques can employed to classify a given type. The skewness and other statistical processing techniques are used to extract the predominant components from the acoustic signatures at ranges exceeding 3000m. Exploiting these techniques will help develop a feature set highly independent of range, providing discrimination based on acoustic elements of the blast wave. Highly reliable discrimination will be achieved with a feed-forward neural network classifier trained on a feature space derived from the distribution of statistical coefficients, frequency spectrum, and higher frequency details found within different energy bands. The processes that are described herein extend current technologies, which emphasis acoustic sensor systems to provide such situational awareness.

Inversion of High Frequency Acoustic Data for Sediment Properties Needed for the Detection and Classification of UXOs

DTIC Science & Technology

2015-05-26

FINAL REPORT Inversion of High Frequency Acoustic Data for Sediment Properties Needed for the Detection and Classification of UXOs SERDP...DOCUMENTATION PAGE Prescribed by ANSI Std. Z39.18 Form Approved OMB No. 0704-0188 The public reporting burden for this collection of information is...2015 Inversion of High Frequency Acoustic Data for Sediment Properties Needed for the Detection and Classification of UXO’s W912HQ-12-C-0049 MR

Effects of the Sea-Bed on Acoustic Propagation.

DTIC Science & Technology

1983-11-15

from the plane-wave reflection curves presented in Fig. 7, which have been computed from a numerical model developed by Hastrup [8]. Since good...La Spezia, Italy, SACLANT ASW Research Centre, 1983. 8. HASTRUP , O.F. Digital analysis of acoustic reflectivity in the Tyrrhenian abyssal plain. J

Mortar and artillery variants classification by exploiting characteristics of the acoustic signature

NASA Astrophysics Data System (ADS)

Hohil, Myron E.; Grasing, David; Desai, Sachi; Morcos, Amir

2007-10-01

Feature extraction methods based on the discrete wavelet transform and multiresolution analysis facilitate the development of a robust classification algorithm that reliably discriminates mortar and artillery variants via acoustic signals produced during the launch/impact events. Utilizing acoustic sensors to exploit the sound waveform generated from the blast for the identification of mortar and artillery variants. Distinct characteristics arise within the different mortar variants because varying HE mortar payloads and related charges emphasize concussive and shrapnel effects upon impact employing varying magnitude explosions. The different mortar variants are characterized by variations in the resulting waveform of the event. The waveform holds various harmonic properties distinct to a given mortar/artillery variant that through advanced signal processing techniques can employed to classify a given set. The DWT and other readily available signal processing techniques will be used to extract the predominant components of these characteristics from the acoustic signatures at ranges exceeding 2km. Exploiting these techniques will help develop a feature set highly independent of range, providing discrimination based on acoustic elements of the blast wave. Highly reliable discrimination will be achieved with a feed-forward neural network classifier trained on a feature space derived from the distribution of wavelet coefficients, frequency spectrum, and higher frequency details found within different levels of the multiresolution decomposition. The process that will be described herein extends current technologies, which emphasis multi modal sensor fusion suites to provide such situational awareness. A two fold problem of energy consumption and line of sight arise with the multi modal sensor suites. The process described within will exploit the acoustic properties of the event to provide variant classification as added situational awareness to the solider.

Extruded Bread Classification on the Basis of Acoustic Emission Signal With Application of Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Świetlicka, Izabela; Muszyński, Siemowit; Marzec, Agata

2015-04-01

The presented work covers the problem of developing a method of extruded bread classification with the application of artificial neural networks. Extruded flat graham, corn, and rye breads differening in water activity were used. The breads were subjected to the compression test with simultaneous registration of acoustic signal. The amplitude-time records were analyzed both in time and frequency domains. Acoustic emission signal parameters: single energy, counts, amplitude, and duration acoustic emission were determined for the breads in four water activities: initial (0.362 for rye, 0.377 for corn, and 0.371 for graham bread), 0.432, 0.529, and 0.648. For classification and the clustering process, radial basis function, and self-organizing maps (Kohonen network) were used. Artificial neural networks were examined with respect to their ability to classify or to cluster samples according to the bread type, water activity value, and both of them. The best examination results were achieved by the radial basis function network in classification according to water activity (88%), while the self-organizing maps network yielded 81% during bread type clustering.

Signal processing for passive detection and classification of underwater acoustic signals

NASA Astrophysics Data System (ADS)

Chung, Kil Woo

2011-12-01

This dissertation examines signal processing for passive detection, classification and tracking of underwater acoustic signals for improving port security and the security of coastal and offshore operations. First, we consider the problem of passive acoustic detection of a diver in a shallow water environment. A frequency-domain multi-band matched-filter approach to swimmer detection is presented. The idea is to break the frequency contents of the hydrophone signals into multiple narrow frequency bands, followed by time averaged (about half of a second) energy calculation over each band. Then, spectra composed of such energy samples over the chosen frequency bands are correlated to form a decision variable. The frequency bands with highest Signal/Noise ratio are used for detection. The performance of the proposed approach is demonstrated for experimental data collected for a diver in the Hudson River. We also propose a new referenceless frequency-domain multi-band detector which, unlike other reference-based detectors, does not require a diver specific signature. Instead, our detector matches to a general feature of the diver spectrum in the high frequency range: the spectrum is roughly periodic in time and approximately flat when the diver exhales. The performance of the proposed approach is demonstrated by using experimental data collected from the Hudson River. Moreover, we present detection, classification and tracking of small vessel signals. Hydroacoustic sensors can be applied for the detection of noise generated by vessels, and this noise can be used for vessel detection, classification and tracking. This dissertation presents recent improvements aimed at the measurement and separation of ship DEMON (Detection of Envelope Modulation on Noise) acoustic signatures in busy harbor conditions. Ship signature measurements were conducted in the Hudson River and NY Harbor. The DEMON spectra demonstrated much better temporal stability compared with the full ship

Real-time GMAW quality classification using an artificial neural network with airborne acoustic signals as inputs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matteson, A.; Morris, R.; Tate, R.

1993-12-31

The acoustic signal produced by the gas metal arc welding (GMAW) arc contains information about the behavior of the arc column, the molten pool and droplet transfer. It is possible to detect some defect producing conditions from the acoustic signal from the GMAW arc. An intelligent sensor, called the Weld Acoustic Monitor (WAM) has been developed to take advantage of this acoustic information in order to provide real-time quality assessment information for process control. The WAM makes use of an Artificial Neural Network (ANN) to classify the characteristic arc acoustic signals of acceptable and unacceptable welds. The ANN used inmore » the Weld Acoustic Monitor developed its own set of rules for this classification problem by learning a data base of known GMAW acoustic signals.« less

Ocean Dynamics and Acoustic Variability in East China Sea

DTIC Science & Technology

2015-09-30

Science and Technology) and KRISO (Korea Research Institute of Ship and Ocean Engineering) to study the coupling of oceanography, acoustics, and...reverberation in the ECS along with geo-acoustic properties of the seabed [2]. On the Korean side, KIOST/ KRISO scientists have been keen on a collaborative...region of the Western Pacific. Motivated by the common interest in the region, SIO and KIOST/ KRISO have agreed to collaborate on a joint research

A Improved Seabed Surface Sand Sampling Device

NASA Astrophysics Data System (ADS)

Luo, X.

2017-12-01

In marine geology research it is necessary to obtain a suf fcient quantity of seabed surface samples, while also en- suring that the samples are in their original state. Currently,there are a number of seabed surface sampling devices available, but we fnd it is very diffcult to obtain sand samples using these devices, particularly when dealing with fne sand. Machine-controlled seabed surface sampling devices are also available, but generally unable to dive into deeper regions of water. To obtain larger quantities of seabed surface sand samples in their original states, many researchers have tried to improve upon sampling devices,but these efforts have generally produced ambiguous results, in our opinion.To resolve this issue, we have designed an improved andhighly effective seabed surface sand sampling device that incorporates the strengths of a variety of sampling devices. It is capable of diving into deepwater to obtain fne sand samples and is also suited for use in streams, rivers, lakes and seas with varying levels of depth (up to 100 m). This device can be used for geological mapping, underwater prospecting, geological engineering and ecological, environmental studies in both marine and terrestrial waters.

A real-time method for autonomous passive acoustic detection-classification of humpback whales.

PubMed

Abbot, Ted A; Premus, Vincent E; Abbot, Philip A

2010-05-01

This paper describes a method for real-time, autonomous, joint detection-classification of humpback whale vocalizations. The approach adapts the spectrogram correlation method used by Mellinger and Clark [J. Acoust. Soc. Am. 107, 3518-3529 (2000)] for bowhead whale endnote detection to the humpback whale problem. The objective is the implementation of a system to determine the presence or absence of humpback whales with passive acoustic methods and to perform this classification with low false alarm rate in real time. Multiple correlation kernels are used due to the diversity of humpback song. The approach also takes advantage of the fact that humpbacks tend to vocalize repeatedly for extended periods of time, and identification is declared only when multiple song units are detected within a fixed time interval. Humpback whale vocalizations from Alaska, Hawaii, and Stellwagen Bank were used to train the algorithm. It was then tested on independent data obtained off Kaena Point, Hawaii in February and March of 2009. Results show that the algorithm successfully classified humpback whales autonomously in real time, with a measured probability of correct classification in excess of 74% and a measured probability of false alarm below 1%.

Acoustic firearm discharge detection and classification in an enclosed environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luzi, Lorenzo; Gonzalez, Eric; Bruillard, Paul

2016-05-01

Two different signal processing algorithms are described for detection and classification of acoustic signals generated by firearm discharges in small enclosed spaces. The first is based on the logarithm of the signal energy. The second is a joint entropy. The current study indicates that a system using both signal energy and joint entropy would be able to both detect weapon discharges and classify weapon type, in small spaces, with high statistical certainty.

Workshop on the Detection, Classification, Localization and Density Estimation of Marine Mammals Using Passive Acoustics - 2015

DTIC Science & Technology

2015-09-30

together the research community working on marine mammal acoustics to discuss detection, classification, localization and density estimation methods...and Density Estimation of Marine Mammals Using Passive Acoustics - 2015 John A. Hildebrand Scripps Institution of Oceanography UCSD La Jolla...dclde LONG-TERM GOALS The goal of this project was to bring together the community of researchers working on methods for detection

Tempo and scale of biogenic effects on high-frequency acoustic propagation near the marine sediment-water interface in shallow water

NASA Astrophysics Data System (ADS)

Jumars, Peter

2003-04-01

Organisms have natural scales, such as lifetimes, body sizes, frequencies of movement to new locations, and residence times of material in digestive systems, and each scale has potential implications for acoustic effects. The effects of groups of organisms, like organisms themselves, aggregate in space and time. This review, including an assortment of unpublished information, examines examples of such aggregations, many of them documented acoustically. Light synchronizes many activities. Macroscopic animals forage primarily under cover of darkness. This phasing applies both to animals that extend appendages above the sediment-water interface and to animals that leave the seabed at night. Whereas their bottom-modifying activities are concentrated in nocturnal or crepuscular fashion, the bottom-modifying activities of the visual feeders follow a different phasing and often dominate the rate of change in acoustic backscatter from the interface. Light also acts through its effects on primary production, often concentrated in a very thin surficial layer atop the seabed. The supersaturation of oxygen does, and microbubble nucleation may, result. Where tidal velocities are large, light-set patterns are often tidally modulated. Activities of animals living below the seabed, however, remain a mystery, whose primary hope for solution is acoustic. [Work supported by ONR and DEPSCoR.

A Improved and Highly Effective Seabed Surface Sand Sampling Device

NASA Astrophysics Data System (ADS)

Liu, Ying

2017-04-01

In marine geology research, it is necessary to obtain a sufficient quantity of seabed surface samples, while also ensuring that the samples are in their original state. Currently, there are a number of seabed surface sampling devices available, but it is very difficult to obtain sand samples using ordinary seabed surface sampling devices, whereas machine-controlled seabed surface sampling devices are unable to dive into deeper regions of water. To obtain larger quantities of samples in their original states, many researchers have tried to improve seabed surface sampling devices, but these efforts have generally produced ambiguous results. To resolve the aforementioned issue, we have designed an improved and highly effective seabed surface sand sampling device, which incorporates the strengths of a variety of sampling devices; it is capable of diving into deeper water regions to obtain sand samples, and is also suited for use in streams, rivers, lakes and seas with varying levels of flow velocities and depth.

Trans-dimensional joint inversion of seabed scattering and reflection data.

PubMed

Steininger, Gavin; Dettmer, Jan; Dosso, Stan E; Holland, Charles W

2013-03-01

This paper examines joint inversion of acoustic scattering and reflection data to resolve seabed interface roughness parameters (spectral strength, exponent, and cutoff) and geoacoustic profiles. Trans-dimensional (trans-D) Bayesian sampling is applied with both the number of sediment layers and the order (zeroth or first) of auto-regressive parameters in the error model treated as unknowns. A prior distribution that allows fluid sediment layers over an elastic basement in a trans-D inversion is derived and implemented. Three cases are considered: Scattering-only inversion, joint scattering and reflection inversion, and joint inversion with the trans-D auto-regressive error model. Including reflection data improves the resolution of scattering and geoacoustic parameters. The trans-D auto-regressive model further improves scattering resolution and correctly differentiates between strongly and weakly correlated residual errors.

Acoustic classification of multiple simultaneous bird species: a multi-instance multi-label approach

Treesearch

F. Briggs; B. Lakshminarayanan; L. Neal; X.Z. Fern; R. Raich; S.F. Hadley; A.S. Hadley; M.G. Betts

2012-01-01

Although field-collected recordings typically contain multiple simultaneously vocalizing birds of different species, acoustic species classification in this setting has received little study so far. This work formulates the problem of classifying the set of species present in an audio recording using the multi-instance multi-label (MIML) framework for machine learning...

Seabed-Structure Interaction: Workshop Report and Recommendations for Future Research Held in Metairie, Louisiana on 5-6 November 1991.

DTIC Science & Technology

1992-02-01

14 Measurements of Sediment Properties and Data Analysis ............................................. 15 object...Object Sensing Methods (Detect/Classification) and (B) Sediment Properties Measurements and Data Analysis . Although important to the understanding of S...characterized by a variety of geological materials, seabed properties, and hydrodynamic processes, the problems of I modeling, analysis , and prediction of S-SI

Morphostructural Analysis and Seabed Shelf Typing

NASA Astrophysics Data System (ADS)

Nikiforov, S. L.; Sorokhtin, N. O.; Koshel', S. M.; Lobkovsky, L. I.

2018-03-01

Analysis of the morphometric characteristics from a study of the Barents Sea seabed has shown that the existing troughs are consistent with geodynamic conclusions, allowing morphological typing into structural slopes and reconstruction of their origin. Thus, the Norwegian-Mezenskaya rift system and Svyataya Anna and Victoria troughs were formed due to stretching of the lithosphere. The South Barents and Medvezinsko- Edzinskaya depressions formed at the generation stage of lithospheric plates due to the collision of several island arcs between outliers of the ancient oceanic crust. The choice of the geomorphic method for studying the seabed is because the science of geomorphology comprehensively studies bottom relief (morphology), its origin, and age. Adequate reconstruction of the causal relationships of exogenous and endogenous processes aids in substantiating the prediction of probable catastrophic seabed events. The results of mathematical calculations have confirmed the geodynamic conclusions within the Barents Sea region.

Reliable classification of high explosive and chemical/biological artillery using acoustic sensors

NASA Astrophysics Data System (ADS)

Desai, Sachi V.; Hohil, Myron E.; Bass, Henry E.; Chambers, Jim

2005-05-01

Feature extraction methods based on the discrete wavelet transform and multiresolution analysis are used to develop a robust classification algorithm that reliably discriminates between conventional and simulated chemical/biological artillery rounds via acoustic signals produced during detonation utilizing a generic acoustic sensor. Based on the transient properties of the signature blast distinct characteristics arise within the different acoustic signatures because high explosive warheads emphasize concussive and shrapnel effects, while chemical/biological warheads are designed to disperse their contents over large areas, therefore employing a slower burning, less intense explosive to mix and spread their contents. The ensuing blast waves are readily characterized by variations in the corresponding peak pressure and rise time of the blast, differences in the ratio of positive pressure amplitude to the negative amplitude, and variations in the overall duration of the resulting waveform. Unique attributes can also be identified that depend upon the properties of the gun tube, projectile speed at the muzzle, and the explosive burn rates of the warhead. The algorithm enables robust classification of various airburst signatures using acoustics. It is capable of being integrated within an existing chemical/biological sensor, a stand-alone generic sensor, or a part of a disparate sensor suite. When emplaced in high-threat areas, this added capability would further provide field personal with advanced battlefield knowledge without the aide of so-called "sniffer" sensors that rely upon air particle information based on direct contact with possible contaminated air. In this work, the discrete wavelet transform is used to extract the predominant components of these characteristics from air burst signatures at ranges exceeding 2km while maintaining temporal sequence of the data to keep relevance to the transient differences of the airburst signatures. Highly reliable

Seabed geodiversity in a glaciated shelf area, the Baltic Sea

NASA Astrophysics Data System (ADS)

Kaskela, Anu Marii; Kotilainen, Aarno Tapio

2017-10-01

Geodiversity describes the heterogeneity of the physical terrain. We have performed basin-wide geodiversity analysis on a glaciated epicontinental seabed to assess geodiversity measures and patterns, locate areas with high geodiversity, and draw conclusions on contributing processes. Geodiversity quantification is a rather new topic and is mainly practiced in land areas. We applied geodiversity methods developed for terrestrial studies to a seabed environment. Three geodiversity parameters, including the richness, patchiness, and geodiversity index, of the Baltic Sea were assessed in a GIS environment based on broad-scale datasets on seabed substrates, structures, and bedrock. A set of environmental and geological variables, which were considered to reflect geological processes under seabed conditions, were compared with the geodiversity to identify some of its drivers. We observed differences in the geodiversity levels of the Baltic subbasins, which are mainly due to basement type/bedrock, roughness, shore density, and glacier-derived processes. The geodiversity of the Baltic Sea generally increases from South to North and from open-sea to high-shore density areas (archipelagos). Crystalline bedrock areas provide more diverse seabed environments than sedimentary rock areas. The analysis helps to inform scientists, marine spatial planners, and managers about abiotic conservation values, the dynamics of the seabed environment, and potential areas with elevated biodiversity.

Sparsity-Based Representation for Classification Algorithms and Comparison Results for Transient Acoustic Signals

DTIC Science & Technology

2016-05-01

large but correlated noise and signal interference (i.e., low -rank interference). Another contribution is the implementation of deep learning...representation, low rank, deep learning 52 Tung-Duong Tran-Luu 301-394-3082Unclassified Unclassified Unclassified UU ii Approved for public release; distribution...Classification of Acoustic Transients 6 3.2 Joint Sparse Representation with Low -Rank Interference 7 3.3 Simultaneous Group-and-Joint Sparse Representation

77 FR 12245 - Deep Seabed Mining: Request for Extension of Exploration Licenses

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Deep Seabed Mining: Request.... Department of Commerce. ACTION: Notice of receipt of application to extend Deep Seabed Mining Exploration... received an application for five-year extensions of Deep Seabed Mining Exploration Licenses USA-1 and USA-4...

Maximum entropy approach to statistical inference for an ocean acoustic waveguide.

PubMed

Knobles, D P; Sagers, J D; Koch, R A

2012-02-01

A conditional probability distribution suitable for estimating the statistical properties of ocean seabed parameter values inferred from acoustic measurements is derived from a maximum entropy principle. The specification of the expectation value for an error function constrains the maximization of an entropy functional. This constraint determines the sensitivity factor (β) to the error function of the resulting probability distribution, which is a canonical form that provides a conservative estimate of the uncertainty of the parameter values. From the conditional distribution, marginal distributions for individual parameters can be determined from integration over the other parameters. The approach is an alternative to obtaining the posterior probability distribution without an intermediary determination of the likelihood function followed by an application of Bayes' rule. In this paper the expectation value that specifies the constraint is determined from the values of the error function for the model solutions obtained from a sparse number of data samples. The method is applied to ocean acoustic measurements taken on the New Jersey continental shelf. The marginal probability distribution for the values of the sound speed ratio at the surface of the seabed and the source levels of a towed source are examined for different geoacoustic model representations. © 2012 Acoustical Society of America

Last century seabed morphodynamics of the Magra River estuary (Western Mediterranean Sea)

NASA Astrophysics Data System (ADS)

Pratellesi, Marta; Ivaldi, Roberta; Ciavola, Paolo; Sinapi, Luigi

2016-04-01

The estimation of morphological and volumetric changes of the delta system at the mouth of the Magra River is presented in this paper using bathymetric and sedimentological data. The data series were collected during several hydro-oceanographic surveys carried out from 1882 to 2014, processed following the hydrographic international standards and stored in the Italian Navy Hydrographic Institute database. In particular, bathymetric data characterized by the same standard and accuracy were collected using different devices such as sounding lines, single-beam and multi-beam acoustic system. This research compares Digital Terrain Models (DTMs), derived from highly accurate bathymetric data and covering different time scales (secular, half-century and decade) in order to assess and quantify the seabed morphodynamics in relation with the river sedimentary budget. The methodology and data exploitation consist mainly in the production of DTMs to study the elevation change, two-dimensional and three dimensional maps, cross-sections of the seabed, difference surfaces and computation of net volumes as well as an historical sedimentological map. These products are also an useful contribution to the aim of EU RISC-KIT Project. The results of the analysis highlight changes in the geometry of the Magra River mouth, of the coastal profile and bottom features primarily due to variations of the sedimentary budget and secondarily to wave dynamics. This behaviour is characterized by evident river mouth and coastal retreat, beach erosion and sediment bars decay and net accretion under periods of high river sediment discharge and elongate bar formation during relatively fair conditions. In the last century the main change is constituted by the disappearance of the typical constructive seabed delta morphology and the transformation into the current small estuary, with microtidal condition. This small estuary has an upper sector where river processes, sediments and bedforms dominate, a

Shallow-Water Mud Acoustics

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Shallow- Water Mud Acoustics William L. Siegmann...shallow water over mud sediments and of acoustic detection, localization, and classification of objects buried in mud. OBJECTIVES • Develop...including long-range conveyance of information; detection, localization, and classification of objects buried in mud; and improvement of shallow water

An algorithm of the wildfire classification by its acoustic emission spectrum using Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Khamukhin, A. A.; Demin, A. Y.; Sonkin, D. M.; Bertoldo, S.; Perona, G.; Kretova, V.

2017-01-01

Crown fires are extremely dangerous as the speed of their distribution is dozen times higher compared to surface fires. Therefore, it is important to classify the fire type as early as possible. A method for forest fires classification exploits their computed acoustic emission spectrum compared with a set of samples of the typical fire acoustic emission spectrum stored in the database. This method implies acquisition acoustic data using Wireless Sensors Networks (WSNs) and their analysis in a central processing and a control center. The paper deals with an algorithm which can be directly implemented on a sensor network node that will allow reducing considerably the network traffic and increasing its efficiency. It is hereby suggested to use the sum of the squares ratio, with regard to amplitudes of low and high frequencies of the wildfire acoustic emission spectrum, as the indicator of a forest fire type. It is shown that the value of the crown fires indicator is several times higher than that of the surface ones. This allows classifying the fire types (crown, surface) in a short time interval and transmitting a fire type indicator code alongside with an alarm signal through the network.

Ocean Space and Seabed Mining

ERIC Educational Resources Information Center

Earney, Fillmore C. F.

1975-01-01

The purpose of this paper is to briefly explore some of the questions with which this and the next generation will be faced concerning the wise and equitable use of ocean space and seabed minerals and to look at contemporary efforts to resolve some of these questions. (Author)

Active acoustic classification via transient resonance scattering

NASA Astrophysics Data System (ADS)

Gaunaurd, Guillermo C.

1992-12-01

The echoes reflected by a sound ping emerging from active sonar when it interacts with a target in its path can be remotely sensed by a receiver. The presented approach capitalizes on an air inverse scattering method that exploits the presence of certain resonance features in these echoes returned by targets to classify them. Classifying underwater objects is important to naval programs such as mine countermeasures (MC) and anti-submarine warfare (ASW) to preclude wasting of ordnance on false targets. Although the classification of complex shapes is still a formidable task, considerable progress has been made in classifying simple shapes such as spheroidal or cylindrical shells. The briefly overviewed methodology has emphasized the extraction, isolation, and labeling of resonance features hidden within the echo, but little has been said about how these could be used to classify a target. A couple of simple examples illustrate exactly how these resonances can be linked to the physical characteristics of the target, allowing for its unambiguous characterization. The procedure, although illustrated with active acoustics (i.e., sonar), can be extended to any active return from any sensor, including radar.

Developing INFOMAR's Seabed Mapping Data to Support a Sustainable Marine Economy

NASA Astrophysics Data System (ADS)

Judge, M. T.; Guinan, J.

2016-02-01

As Ireland's national seabed mapping programme, INFOMAR1 (INtegrated mapping FOr the sustainable development of Ireland's MARine resource) enters its eleventh year it continues to provide pivotal seabed mapping data products, e.g. databases, charts and physical habitat maps to support Ireland's Integrated Marine Plan. The programme, jointly coordinated by the Geological Survey of Ireland and the Marine Institute, has gained a world class reputation for developing seabed mapping technologies, infrastructure and expertise. In the government's current Integrated Marine Plan, the programme's critical role in marine spatial planning enabling infrastructural development, research and education has been cited2. INFOMAR's free data policy supports a thriving maritime economy by promoting easy access to seabed mapping datasets that underpin; maritime safety, security and surveillance, governance, business development, research and technology innovation and infrastructure. The first hydrographic surveys of the national marine mapping programme mapped the extent of Ireland's deepest offshore area, whilst in recent years the focus has been to map the coastal and shallow areas. Targeted coastal areas include 26 bays and 3 priority areas for which specialised equipment, techniques and vessels are required. This talk will discuss how the INFOMAR programme has evolved to address the scientific and technological challenges of seabed mapping across a range of water depths; particularly the challenges associated with addressing inshore data gaps. It will describe how the data converts to bathymetric and geological maps detailing seabed characteristics and habitats. We will expand on how maps are: incorporated into collaborative marine projects such as EMODnet, commercialised to identify marine resources and used as marine decision support tools that drive policy and promote protection of the vastly under discovered marine area.

Nearshore Hydroacoustic Seafloor Mapping In The German Bight (North Sea): Hydroacoustic Interpretation With And Without Classification

NASA Astrophysics Data System (ADS)

Hass, H. C.; Mielck, F.; Papenmeier, S.

2016-12-01

Nearshore habitats are in constant dynamic change. They need regular assessment and appropriate monitoring of areas of special interest. To accomplish this, hydroacoustic seabed characterization tools are applied to allow for cost-effective and efficient mapping of the seafloor. In this context single beam echosounders (SBES) systems provide a comprehensive view by analyzing the hardness and roughness characteristics of the seafloor. Interpolation between transect lines becomes necessary when gapless maps are needed. This study presents a simple method to process and visualize data recorded with RoxAnn (Sonavision, Edinburgh, UK) and similar SBES. Both, hardness and roughness data are merged to one combined parameter that receives a color code (RGB) according to the acoustic properties of the seafloor. This color information is then interpolated to obtain an area-wide map that provides unclassified and thus unbiased seabed information. The RGB color data can subsequently be used for classification and modeling purposes. Four surveys are shown from a morphologically complex nearshore area west of the island of Helgoland (SE North Sea). The area has complex textural and dynamic characteristics reaching from outcropping bedrock via sandy to muddy areas with mostly gradual transitions. RoxAnn data allow to discriminate all seafloor types that were suggested by ground-truth information (seafloor samples, video). The area appears to be fluctuating within certain limits. Sediment import (sand and fluid mud) paths can be reconstructed. Manually, six RoxAnn zones (RZ) were identified and left without hard boundaries to better match the seafloor types of the study site. The k-means fuzzy cluster analysis employed yields best results with 3 classes. We show that interpretations on the basis of largely non-classified, color-coded and interpolated data provide the best gain of information in the highest possible resolution. Classification with hard boundaries is necessary for

Improved Maturity and Ripeness Classifications of Magnifera Indica cv. Harumanis Mangoes through Sensor Fusion of an Electronic Nose and Acoustic Sensor

PubMed Central

Zakaria, Ammar; Shakaff, Ali Yeon Md; Masnan, Maz Jamilah; Saad, Fathinul Syahir Ahmad; Adom, Abdul Hamid; Ahmad, Mohd Noor; Jaafar, Mahmad Nor; Abdullah, Abu Hassan; Kamarudin, Latifah Munirah

2012-01-01

In recent years, there have been a number of reported studies on the use of non-destructive techniques to evaluate and determine mango maturity and ripeness levels. However, most of these reported works were conducted using single-modality sensing systems, either using an electronic nose, acoustics or other non-destructive measurements. This paper presents the work on the classification of mangoes (Magnifera Indica cv. Harumanis) maturity and ripeness levels using fusion of the data of an electronic nose and an acoustic sensor. Three groups of samples each from two different harvesting times (week 7 and week 8) were evaluated by the e-nose and then followed by the acoustic sensor. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to discriminate the mango harvested at week 7 and week 8 based solely on the aroma and volatile gases released from the mangoes. However, when six different groups of different maturity and ripeness levels were combined in one classification analysis, both PCA and LDA were unable to discriminate the age difference of the Harumanis mangoes. Instead of six different groups, only four were observed using the LDA, while PCA showed only two distinct groups. By applying a low level data fusion technique on the e-nose and acoustic data, the classification for maturity and ripeness levels using LDA was improved. However, no significant improvement was observed using PCA with data fusion technique. Further work using a hybrid LDA-Competitive Learning Neural Network was performed to validate the fusion technique and classify the samples. It was found that the LDA-CLNN was also improved significantly when data fusion was applied. PMID:22778629

Improved maturity and ripeness classifications of Magnifera Indica cv. Harumanis mangoes through sensor fusion of an electronic nose and acoustic sensor.

PubMed

Zakaria, Ammar; Shakaff, Ali Yeon Md; Masnan, Maz Jamilah; Saad, Fathinul Syahir Ahmad; Adom, Abdul Hamid; Ahmad, Mohd Noor; Jaafar, Mahmad Nor; Abdullah, Abu Hassan; Kamarudin, Latifah Munirah

2012-01-01

In recent years, there have been a number of reported studies on the use of non-destructive techniques to evaluate and determine mango maturity and ripeness levels. However, most of these reported works were conducted using single-modality sensing systems, either using an electronic nose, acoustics or other non-destructive measurements. This paper presents the work on the classification of mangoes (Magnifera Indica cv. Harumanis) maturity and ripeness levels using fusion of the data of an electronic nose and an acoustic sensor. Three groups of samples each from two different harvesting times (week 7 and week 8) were evaluated by the e-nose and then followed by the acoustic sensor. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to discriminate the mango harvested at week 7 and week 8 based solely on the aroma and volatile gases released from the mangoes. However, when six different groups of different maturity and ripeness levels were combined in one classification analysis, both PCA and LDA were unable to discriminate the age difference of the Harumanis mangoes. Instead of six different groups, only four were observed using the LDA, while PCA showed only two distinct groups. By applying a low level data fusion technique on the e-nose and acoustic data, the classification for maturity and ripeness levels using LDA was improved. However, no significant improvement was observed using PCA with data fusion technique. Further work using a hybrid LDA-Competitive Learning Neural Network was performed to validate the fusion technique and classify the samples. It was found that the LDA-CLNN was also improved significantly when data fusion was applied.

Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance.

PubMed

Hiddink, Jan Geert; Jennings, Simon; Sciberras, Marija; Szostek, Claire L; Hughes, Kathryn M; Ellis, Nick; Rijnsdorp, Adriaan D; McConnaughey, Robert A; Mazor, Tessa; Hilborn, Ray; Collie, Jeremy S; Pitcher, C Roland; Amoroso, Ricardo O; Parma, Ana M; Suuronen, Petri; Kaiser, Michel J

2017-08-01

Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after trawling. Depletion of biota and trawl penetration into the seabed are highly correlated. Otter trawls caused the least depletion, removing 6% of biota per pass and penetrating the seabed on average down to 2.4 cm, whereas hydraulic dredges caused the most depletion, removing 41% of biota and penetrating the seabed on average 16.1 cm. Median recovery times posttrawling (from 50 to 95% of unimpacted biomass) ranged between 1.9 and 6.4 y. By accounting for the effects of penetration depth, environmental variation, and uncertainty, the models explained much of the variability of depletion and recovery estimates from single studies. Coupled with large-scale, high-resolution maps of trawling frequency and habitat, our estimates of depletion and recovery rates enable the assessment of trawling impacts on unprecedented spatial scales.

Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance

PubMed Central

Hiddink, Jan Geert; Jennings, Simon; Sciberras, Marija; Szostek, Claire L.; Hughes, Kathryn M.; Ellis, Nick; Rijnsdorp, Adriaan D.; McConnaughey, Robert A.; Mazor, Tessa; Hilborn, Ray; Collie, Jeremy S.; Pitcher, C. Roland; Amoroso, Ricardo O.; Parma, Ana M.; Suuronen, Petri; Kaiser, Michel J.

2017-01-01

Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after trawling. Depletion of biota and trawl penetration into the seabed are highly correlated. Otter trawls caused the least depletion, removing 6% of biota per pass and penetrating the seabed on average down to 2.4 cm, whereas hydraulic dredges caused the most depletion, removing 41% of biota and penetrating the seabed on average 16.1 cm. Median recovery times posttrawling (from 50 to 95% of unimpacted biomass) ranged between 1.9 and 6.4 y. By accounting for the effects of penetration depth, environmental variation, and uncertainty, the models explained much of the variability of depletion and recovery estimates from single studies. Coupled with large-scale, high-resolution maps of trawling frequency and habitat, our estimates of depletion and recovery rates enable the assessment of trawling impacts on unprecedented spatial scales. PMID:28716926

Surface area and the seabed area, volume, depth, slope, and topographic variation for the world's seas, oceans, and countries.

PubMed

Costello, Mark John; Cheung, Alan; De Hauwere, Nathalie

2010-12-01

Depth and topography directly and indirectly influence most ocean environmental conditions, including light penetration and photosynthesis, sedimentation, current movements and stratification, and thus temperature and oxygen gradients. These parameters are thus likely to influence species distribution patterns and productivity in the oceans. They may be considered the foundation for any standardized classification of ocean ecosystems and important correlates of metrics of biodiversity (e.g., species richness and composition, fisheries). While statistics on ocean depth and topography are often quoted, how they were derived is rarely cited, and unless calculated using the same spatial resolution the resulting statistics will not be strictly comparable. We provide such statistics using the best available resolution (1-min) global bathymetry, and open source digital maps of the world's seas and oceans and countries' Exclusive Economic Zones, using a standardized methodology. We created a terrain map and calculated sea surface and seabed area, volume, and mean, standard deviation, maximum, and minimum, of both depth and slope. All the source data and our database are freely available online. We found that although the ocean is flat, and up to 71% of the area has a < 1 degree slope. It had over 1 million approximately circular features that may be seamounts or sea-hills as well as prominent mountain ranges or ridges. However, currently available global data significantly underestimate seabed slopes. The 1-min data set used here predicts there are 68,669 seamounts compared to the 30,314 previously predicted using the same method but lower spatial resolution data. The ocean volume exceeds 1.3 billion km(3) (or 1.3 sextillion liters), and sea surface and seabed areas over 354 million km(2). We propose the coefficient of variation of slope as an index of topographic heterogeneity. Future studies may improve on this database, for example by using a more detailed bathymetry

Model selection and Bayesian inference for high-resolution seabed reflection inversion.

PubMed

Dettmer, Jan; Dosso, Stan E; Holland, Charles W

2009-02-01

This paper applies Bayesian inference, including model selection and posterior parameter inference, to inversion of seabed reflection data to resolve sediment structure at a spatial scale below the pulse length of the acoustic source. A practical approach to model selection is used, employing the Bayesian information criterion to decide on the number of sediment layers needed to sufficiently fit the data while satisfying parsimony to avoid overparametrization. Posterior parameter inference is carried out using an efficient Metropolis-Hastings algorithm for high-dimensional models, and results are presented as marginal-probability depth distributions for sound velocity, density, and attenuation. The approach is applied to plane-wave reflection-coefficient inversion of single-bounce data collected on the Malta Plateau, Mediterranean Sea, which indicate complex fine structure close to the water-sediment interface. This fine structure is resolved in the geoacoustic inversion results in terms of four layers within the upper meter of sediments. The inversion results are in good agreement with parameter estimates from a gravity core taken at the experiment site.

Can single classifiers be as useful as model ensembles to produce benthic seabed substratum maps?

NASA Astrophysics Data System (ADS)

Turner, Joseph A.; Babcock, Russell C.; Hovey, Renae; Kendrick, Gary A.

2018-05-01

Numerous machine-learning classifiers are available for benthic habitat map production, which can lead to different results. This study highlights the performance of the Random Forest (RF) classifier, which was significantly better than Classification Trees (CT), Naïve Bayes (NB), and a multi-model ensemble in terms of overall accuracy, Balanced Error Rate (BER), Kappa, and area under the curve (AUC) values. RF accuracy was often higher than 90% for each substratum class, even at the most detailed level of the substratum classification and AUC values also indicated excellent performance (0.8-1). Total agreement between classifiers was high at the broadest level of classification (75-80%) when differentiating between hard and soft substratum. However, this sharply declined as the number of substratum categories increased (19-45%) including a mix of rock, gravel, pebbles, and sand. The model ensemble, produced from the results of all three classifiers by majority voting, did not show any increase in predictive performance when compared to the single RF classifier. This study shows how a single classifier may be sufficient to produce benthic seabed maps and model ensembles of multiple classifiers.

Seabed mapping and characterization of sediment variability using the usSEABED data base

USGS Publications Warehouse

Goff, J.A.; Jenkins, C.J.; Jeffress, Williams S.

2008-01-01

We present a methodology for statistical analysis of randomly located marine sediment point data, and apply it to the US continental shelf portions of usSEABED mean grain size records. The usSEABED database, like many modern, large environmental datasets, is heterogeneous and interdisciplinary. We statistically test the database as a source of mean grain size data, and from it provide a first examination of regional seafloor sediment variability across the entire US continental shelf. Data derived from laboratory analyses ("extracted") and from word-based descriptions ("parsed") are treated separately, and they are compared statistically and deterministically. Data records are selected for spatial analysis by their location within sample regions: polygonal areas defined in ArcGIS chosen by geography, water depth, and data sufficiency. We derive isotropic, binned semivariograms from the data, and invert these for estimates of noise variance, field variance, and decorrelation distance. The highly erratic nature of the semivariograms is a result both of the random locations of the data and of the high level of data uncertainty (noise). This decorrelates the data covariance matrix for the inversion, and largely prevents robust estimation of the fractal dimension. Our comparison of the extracted and parsed mean grain size data demonstrates important differences between the two. In particular, extracted measurements generally produce finer mean grain sizes, lower noise variance, and lower field variance than parsed values. Such relationships can be used to derive a regionally dependent conversion factor between the two. Our analysis of sample regions on the US continental shelf revealed considerable geographic variability in the estimated statistical parameters of field variance and decorrelation distance. Some regional relationships are evident, and overall there is a tendency for field variance to be higher where the average mean grain size is finer grained

Incorporating ecosystem services into environmental management of deep-seabed mining

NASA Astrophysics Data System (ADS)

Le, Jennifer T.; Levin, Lisa A.; Carson, Richard T.

2017-03-01

Accelerated exploration of minerals in the deep sea over the past decade has raised the likelihood that commercial mining of the deep seabed will commence in the near future. Environmental concerns create a growing urgency for development of environmental regulations under commercial exploitation. Here, we consider an ecosystem services approach to the environmental policy and management of deep-sea mineral resources. Ecosystem services link the environment and human well-being, and can help improve sustainability and stewardship of the deep sea by providing a quantitative basis for decision-making. This paper briefly reviews ecosystem services provided by habitats targeted for deep-seabed mining (hydrothermal vents, seamounts, nodule provinces, and phosphate-rich margins), and presents practical steps to incorporate ecosystem services into deep-seabed mining regulation. The linkages and translation between ecosystem structure, ecological function (including supporting services), and ecosystem services are highlighted as generating human benefits. We consider criteria for identifying which ecosystem services are vulnerable to potential mining impacts, the role of ecological functions in providing ecosystem services, development of ecosystem service indicators, valuation of ecosystem services, and implementation of ecosystem services concepts. The first three steps put ecosystem services into a deep-seabed mining context; the last two steps help to incorporate ecosystem services into a management and decision-making framework. Phases of environmental planning discussed in the context of ecosystem services include conducting strategic environmental assessments, collecting baseline data, monitoring, establishing marine protected areas, assessing cumulative impacts, identifying thresholds and triggers, and creating an environmental damage compensation regime. We also identify knowledge gaps that need to be addressed in order to operationalize ecosystem services

Mapping and classifying the seabed of the West Greenland continental shelf

NASA Astrophysics Data System (ADS)

Gougeon, S.; Kemp, K. M.; Blicher, M. E.; Yesson, C.

2017-03-01

Marine benthic habitats support a diversity of marine organisms that are both economically and intrinsically valuable. Our knowledge of the distribution of these habitats is largely incomplete, particularly in deeper water and at higher latitudes. The western continental shelf of Greenland is one example of a deep (more than 500 m) Arctic region with limited information available. This study uses an adaptation of the EUNIS seabed classification scheme to document benthic habitats in the region of the West Greenland shrimp trawl fishery from 60°N to 72°N in depths of 61-725 m. More than 2000 images collected at 224 stations between 2011 and 2015 were grouped into 7 habitat classes. A classification model was developed using environmental proxies to make habitat predictions for the entire western shelf (200-700 m below 72°N). The spatial distribution of habitats correlates with temperature and latitude. Muddy sediments appear in northern and colder areas whereas sandy and rocky areas dominate in the south. Southern regions are also warmer and have stronger currents. The Mud habitat is the most widespread, covering around a third of the study area. There is a general pattern that deep channels and basins are dominated by muddy sediments, many of which are fed by glacial sedimentation and outlets from fjords, while shallow banks and shelf have a mix of more complex habitats. This first habitat classification map of the West Greenland shelf will be a useful tool for researchers, management and conservationists.

On the use of drift bottle and seabed drifter data in coastal management

NASA Technical Reports Server (NTRS)

Welch, C. S.; Norcross, J. J.

1973-01-01

The use of drift bottle and seabed drifter information for use in coastal management is discussed. The drift bottle/seabed drifter portion of VIMS project MACONS (Mid Atlantic Continental Shelf) is described as an example of how a comprehensive survey using drift bottles and seabed drifters provides data useful for coastal management. The data from MACONS are analyzed to answer specific questions of interest to several different coastal managers: a manager siting a deep oil port, one siting a sewage outfall, a manager responsible for setting up emergency beach protection procedures before an accident occurs, and a manager responsible for the environmental quality of a particular small section of coastline.

Evidence for cultural dialects in vocal emotion expression: acoustic classification within and across five nations.

PubMed

Laukka, Petri; Neiberg, Daniel; Elfenbein, Hillary Anger

2014-06-01

The possibility of cultural differences in the fundamental acoustic patterns used to express emotion through the voice is an unanswered question central to the larger debate about the universality versus cultural specificity of emotion. This study used emotionally inflected standard-content speech segments expressing 11 emotions produced by 100 professional actors from 5 English-speaking cultures. Machine learning simulations were employed to classify expressions based on their acoustic features, using conditions where training and testing were conducted on stimuli coming from either the same or different cultures. A wide range of emotions were classified with above-chance accuracy in cross-cultural conditions, suggesting vocal expressions share important characteristics across cultures. However, classification showed an in-group advantage with higher accuracy in within- versus cross-cultural conditions. This finding demonstrates cultural differences in expressive vocal style, and supports the dialect theory of emotions according to which greater recognition of expressions from in-group members results from greater familiarity with culturally specific expressive styles.

The morphology and structure of the Hannibal Bank fisheries management zone, Pacific Panama using acoustic seabed mapping.

PubMed

Cunningham, Sarah; Guzman, Hector M; Bates, Richard

2013-12-01

The Hannibal Bank sits within the Coiba UNESCO World Heritage Site in Pacific Panama and is also a fisheries management zone. Despite the protected status of the area and the importance of the Bank for commercial fish species such as snapper and tuna, the seamount has received no detailed survey except some collection of organisms. This study mapped the major topographic features and complexity of the Hannibal Bank seamount using acoustic remote sensing. A survey area of around 125 km2 was defined using existing charts and side-scan sonar data were collected during July 2008. A bathymetric output was imported to ArcGIS where a digital bathymetric model and slope map were created. The Benthic Terrain Modeler (BTM) extension for ArcGIS was used to calculate bathymetric position index and rugosity, and used to create a map of zones representing the various seabed morphology zones. The Hannibal bank is an elongated, triangular guyot (flat topped seamount), which ranges in depth from 53m to 416m, covers an area of 76 km2 and is 14.4 km long and 7.1 km wide. Hannibal bank is composed of steep slopes, more gentle slopes, top of the seamount, crests (elevated ridges at the top of the pinnacles), rugose areas (on crests, top of seamount and slope), gullies and pinnacles. The bank is asymmetric in nature with the Northerly side having a relatively gentle slope with gullies across the surface compared to the SouthWest side which is far steeper and more rugose. There are two pinnacles to the North and South East of the bank that range in depth from 180 to 333 m. Rocky substrate makes up 22.6 km2 of the bank and sediment 37.8 km2. The bank and its steeply sided, rugose areas and pinnacles provide upright structures which can disrupt and topographically enhance currents, increasing productivity. The rugose areas of Hannibal Bank should be primary targets for further research efforts as they may contain corals and their rugosity indicates that these should be some of the highest

usSEABED: Pacific coast (California, Oregon, Washington) offshore surficial-sediment data release

USGS Publications Warehouse

Reid, Jane A.; Reid, Jamey M.; Jenkins, Chris J.; Zimmermann, Mark; Williams, S. Jeffress; Field, Michael E.

2006-01-01

Over the past 50 years there has been an explosion in scientific interest, research effort, and information gathered on the geologic sedimentary character of the continental margin of the United States. Data and information from thousands of publications have greatly increased our scientific understanding of the geologic origins of the margin surface but rarely have those data been combined and integrated. This publication is the first release of the Pacific coast data from the usSEABED database. The report contains a compilation of published and unpublished sediment texture and other geologic data about the sea floor from diverse sources. usSEABED is an innovative database system developed to unify assorted data, with the data processed by the dbSEABED system. Examples of maps displaying attributes such as grain size and sediment color are included. This database contains information that is a scientific foundation for the U.S. Geological Survey (USGS) Sea floor Mapping and Benthic Habitats project and the Marine Aggregate Resources and Processes assessment project, and will be useful to the marine science community for other studies of the Pacific coast continental margin. The publication is divided into 10 sections: Home, Introduction, Content, usSEABED (data), dbSEABED (processing), Data Catalog, References, Contacts, Acknowledgments, and Frequently Asked Questions. Use the navigation bar on the left to navigate to specific sections of this report. Underlined topics throughout the publication are links to more information. Links to specific and detailed information on processing and to those to pages outside this report will open in a new browser window.

Uncertainty quantification of seabed parameters for large data volumes along survey tracks with a tempered particle filter

NASA Astrophysics Data System (ADS)

Dettmer, J.; Quijano, J. E.; Dosso, S. E.; Holland, C. W.; Mandolesi, E.

2016-12-01

Geophysical seabed properties are important for the detection and classification of unexploded ordnance. However, current surveying methods such as vertical seismic profiling, coring, or inversion are of limited use when surveying large areas with high spatial sampling density. We consider surveys based on a source and receiver array towed by an autonomous vehicle which produce large volumes of seabed reflectivity data that contain unprecedented and detailed seabed information. The data are analyzed with a particle filter, which requires efficient reflection-coefficient computation, efficient inversion algorithms and efficient use of computer resources. The filter quantifies information content of multiple sequential data sets by considering results from previous data along the survey track to inform the importance sampling at the current point. Challenges arise from environmental changes along the track where the number of sediment layers and their properties change. This is addressed by a trans-dimensional model in the filter which allows layering complexity to change along a track. Efficiency is improved by likelihood tempering of various particle subsets and including exchange moves (parallel tempering). The filter is implemented on a hybrid computer that combines central processing units (CPUs) and graphics processing units (GPUs) to exploit three levels of parallelism: (1) fine-grained parallel computation of spherical reflection coefficients with a GPU implementation of Levin integration; (2) updating particles by concurrent CPU processes which exchange information using automatic load balancing (coarse grained parallelism); (3) overlapping CPU-GPU communication (a major bottleneck) with GPU computation by staggering CPU access to the multiple GPUs. The algorithm is applied to spherical reflection coefficients for data sets along a 14-km track on the Malta Plateau, Mediterranean Sea. We demonstrate substantial efficiency gains over previous methods. [This

Near-specular acoustic scattering from a buried submarine mud volcano.

PubMed

Gerig, Anthony L; Holland, Charles W

2007-12-01

Submarine mud volcanoes are objects that form on the seafloor due to the emission of gas and fluidized sediment from the Earth's interior. They vary widely in size, can be exposed or buried, and are of interest to the underwater acoustics community as potential sources of active sonar clutter. Coincident seismic reflection data and low frequency bistatic scattering data were gathered from one such buried mud volcano located in the Straits of Sicily. The bistatic data were generated using a pulsed piston source and a 64-element horizontal array, both towed over the top of the volcano. The purpose of this work was to appropriately model low frequency scattering from the volcano using the bistatic returns, seismic bathymetry, and knowledge of the general geoacoustic properties of the area's seabed to guide understanding and model development. Ray theory, with some approximations, was used to model acoustic propagation through overlying layers. Due to the volcano's size, scattering was modeled using geometric acoustics and a simple representation of volcano shape. Modeled bistatic data compared relatively well with experimental data, although some features remain unexplained. Results of an inversion for the volcano's reflection coefficient indicate that it may be acoustically softer than expected.

Coastal Seabed Mapping with Hyperspectral and Lidar data

NASA Astrophysics Data System (ADS)

Taramelli, A.; Valentini, E.; Filipponi, F.; Cappucci, S.

2017-12-01

A synoptic view of the coastal seascape and its dynamics needs a quantitative ability to dissect different components over the complexity of the seafloor where a mixture of geo - biological facies determines geomorphological features and their coverage. The present study uses an analytical approach that takes advantage of a multidimensional model to integrate different data sources from airborne Hyperspectral and LiDAR remote sensing and in situ measurements to detect antropogenic features and ecological `tipping points' in coastal seafloors. The proposed approach has the ability to generate coastal seabed maps using: 1) a multidimensional dataset to account for radiometric and morphological properties of waters and the seafloor; 2) a field spectral library to assimilate the high environmental variability into the multidimensional model; 3) a final classification scheme to represent the spatial gradients in the seafloor. The spatial pattern of the response to anthropogenic forcing may be indistinguishable from patterns of natural variability. It is argued that this novel approach to define tipping points following anthropogenic impacts could be most valuable in the management of natural resources and the economic development of coastal areas worldwide. Examples are reported from different sites of the Mediterranean Sea, both from Marine Protected and un-Protected Areas.

Bio-inspired UAV routing, source localization, and acoustic signature classification for persistent surveillance

NASA Astrophysics Data System (ADS)

Burman, Jerry; Hespanha, Joao; Madhow, Upamanyu; Pham, Tien

2011-06-01

A team consisting of Teledyne Scientific Company, the University of California at Santa Barbara and the Army Research Laboratory* is developing technologies in support of automated data exfiltration from heterogeneous battlefield sensor networks to enhance situational awareness for dismounts and command echelons. Unmanned aerial vehicles (UAV) provide an effective means to autonomously collect data from a sparse network of unattended ground sensors (UGSs) that cannot communicate with each other. UAVs are used to reduce the system reaction time by generating autonomous collection routes that are data-driven. Bio-inspired techniques for search provide a novel strategy to detect, capture and fuse data. A fast and accurate method has been developed to localize an event by fusing data from a sparse number of UGSs. This technique uses a bio-inspired algorithm based on chemotaxis or the motion of bacteria seeking nutrients in their environment. A unique acoustic event classification algorithm was also developed based on using swarm optimization. Additional studies addressed the problem of routing multiple UAVs, optimally placing sensors in the field and locating the source of gunfire at helicopters. A field test was conducted in November of 2009 at Camp Roberts, CA. The field test results showed that a system controlled by bio-inspired software algorithms can autonomously detect and locate the source of an acoustic event with very high accuracy and visually verify the event. In nine independent test runs of a UAV, the system autonomously located the position of an explosion nine times with an average accuracy of 3 meters. The time required to perform source localization using the UAV was on the order of a few minutes based on UAV flight times. In June 2011, additional field tests of the system will be performed and will include multiple acoustic events, optimal sensor placement based on acoustic phenomenology and the use of the International Technology Alliance (ITA

Acoustic diagnosis of pulmonary hypertension: automated speech- recognition-inspired classification algorithm outperforms physicians

NASA Astrophysics Data System (ADS)

Kaddoura, Tarek; Vadlamudi, Karunakar; Kumar, Shine; Bobhate, Prashant; Guo, Long; Jain, Shreepal; Elgendi, Mohamed; Coe, James Y.; Kim, Daniel; Taylor, Dylan; Tymchak, Wayne; Schuurmans, Dale; Zemp, Roger J.; Adatia, Ian

2016-09-01

We hypothesized that an automated speech- recognition-inspired classification algorithm could differentiate between the heart sounds in subjects with and without pulmonary hypertension (PH) and outperform physicians. Heart sounds, electrocardiograms, and mean pulmonary artery pressures (mPAp) were recorded simultaneously. Heart sound recordings were digitized to train and test speech-recognition-inspired classification algorithms. We used mel-frequency cepstral coefficients to extract features from the heart sounds. Gaussian-mixture models classified the features as PH (mPAp ≥ 25 mmHg) or normal (mPAp < 25 mmHg). Physicians blinded to patient data listened to the same heart sound recordings and attempted a diagnosis. We studied 164 subjects: 86 with mPAp ≥ 25 mmHg (mPAp 41 ± 12 mmHg) and 78 with mPAp < 25 mmHg (mPAp 17 ± 5 mmHg) (p  < 0.005). The correct diagnostic rate of the automated speech-recognition-inspired algorithm was 74% compared to 56% by physicians (p = 0.005). The false positive rate for the algorithm was 34% versus 50% (p = 0.04) for clinicians. The false negative rate for the algorithm was 23% and 68% (p = 0.0002) for physicians. We developed an automated speech-recognition-inspired classification algorithm for the acoustic diagnosis of PH that outperforms physicians that could be used to screen for PH and encourage earlier specialist referral.

Estimation of Ocean and Seabed Parameters and Processes Using Low Frequency Acoustic Signals

DTIC Science & Technology

2011-09-01

Dr. Mohsen Badiey (University of Delaware), Kevin Smith (Naval Postgraduate School), Dr. James F. Lynch and Dr. Y.-T. Lin (Woods Hole Oceanographic...Wilson (ARL, University of Texas) in this topic. 3. Finite Element Modeling of wave propagation: Doctoral student, Hui- Kwan Kim, is modeling wave...student Hui- Kwan Kim is focusing on finite element modeling of wave propagation. RESULTS 1. Acoustic variability in the presence of internal waves

Quantitative Evaluations of the Effects of the Seabed Sediments on Scattering and Propagation of Acoustics Energy in Shallow Oceans

DTIC Science & Technology

1999-09-30

Dec. (1998) Yamamoto, T., “ A poroelastic model of highly permeable rocks,” Geophysics, revised August 1999a. Yamamoto, T., “ Acoustical imaging of...scattering mechanisms (volume fluctuation, bottom and sub-bottom roughness) on the acoustic propagation and scattering, and the effects of poroelastic ...properties of the sediments on the propagation of acoustic waves. OBJECTIVES To develop a universal (forward/inverse) model for the seafloor roughness

Use of Seafloor Electromagnetic and Acoustic Backscatter Data for Seafloor Classification: An Example From Martha's Vineyard, Massachusetts.

NASA Astrophysics Data System (ADS)

Evans, R. L.; Kraft, B.; Mayer, L.

2006-12-01

Near surface offshore geophysical data allow sediment classification in coastal settings at high levels of spatial detail. We present data from offshore Martha's Vineyard, Massachusetts collected as part of the Office of Naval Researchś Mine Burial Prediction program. Seafloor electromagnetic data provide estimates of near surface porosity at approximately 10m intervals along each tow-line. In addition, the area has undergone repeat surveys with high resolution acoustic backscatter and bathymetry. In some locations, the geophysical data has been groundtruthed by grab sampling and coring. We examine the spatial variability in near surface sediment properties on the basis of the geophysical data. The EM data are particularly well suited to constructing semi-variograms to display length scales of variability. Preliminary examination does not show any obvious correlation between the EM data and acoustic backscatter, however, further processing of the backscatter is being carried out and so this result is tentative.

Voice based gender classification using machine learning

NASA Astrophysics Data System (ADS)

Raahul, A.; Sapthagiri, R.; Pankaj, K.; Vijayarajan, V.

2017-11-01

Gender identification is one of the major problem speech analysis today. Tracing the gender from acoustic data i.e., pitch, median, frequency etc. Machine learning gives promising results for classification problem in all the research domains. There are several performance metrics to evaluate algorithms of an area. Our Comparative model algorithm for evaluating 5 different machine learning algorithms based on eight different metrics in gender classification from acoustic data. Agenda is to identify gender, with five different algorithms: Linear Discriminant Analysis (LDA), K-Nearest Neighbour (KNN), Classification and Regression Trees (CART), Random Forest (RF), and Support Vector Machine (SVM) on basis of eight different metrics. The main parameter in evaluating any algorithms is its performance. Misclassification rate must be less in classification problems, which says that the accuracy rate must be high. Location and gender of the person have become very crucial in economic markets in the form of AdSense. Here with this comparative model algorithm, we are trying to assess the different ML algorithms and find the best fit for gender classification of acoustic data.

A Lesson in Complexity: Seabed Minerals and Easter Island.

ERIC Educational Resources Information Center

Druker, Kristen

1984-01-01

This high school-level classroom activity presents a hypothetical situation based on scientific fact concerning the likelihood that seabed mineral deposits lie off Easter Island. Activity goals, instructional strategies, and instructions for students are included. (JN)

Nuclear waste disposal in subseabed geologic formatons: the Seabed Disposal Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, D.R.

1979-05-01

The goal of the Seabed Disposal Program is to assess the technical and environmental feasibility of using geologic formations under the sea floor for the disposal of processed high-level radioactive wastes or repackaged spent reactor fuel. Studies are focused on the abyssal hill regions of the sea floors in the middle of tectonic plates and under massive surface current gyres. The red-clay sediments here are from 50 to 100 meters thick, are continuously depositional (without periods of erosion), and have been geologically and climatologically stable for millions of years. Mineral deposits and biological activity are minimal, and bottom currents aremore » weak and variable. Five years of research have revealed no technological reason why nuclear waste disposal in these areas would be impractical. However, scientific assessment is not complete. Also, legal political, and sociological factors may well become the governing elements in such use of international waters. These factors are being examined as part of the work of the Seabed Working Group, an international adjunct of the Seabed Program, with members from France, England, Japan, Canada, and the United States.« less

U.S. Geological Survey ArcMap Sediment Classification tool

USGS Publications Warehouse

O'Malley, John

2007-01-01

The U.S. Geological Survey (USGS) ArcMap Sediment Classification tool is a custom toolbar that extends the Environmental Systems Research Institute, Inc. (ESRI) ArcGIS 9.2 Desktop application to aid in the analysis of seabed sediment classification. The tool uses as input either a point data layer with field attributes containing percentage of gravel, sand, silt, and clay or four raster data layers representing a percentage of sediment (0-100%) for the various sediment grain size analysis: sand, gravel, silt and clay. This tool is designed to analyze the percent of sediment at a given location and classify the sediments according to either the Folk (1954, 1974) or Shepard (1954) as modified by Schlee(1973) classification schemes. The sediment analysis tool is based upon the USGS SEDCLASS program (Poppe, et al. 2004).

Recent Advances in Tsunami-Seabed-Structure Interaction from Geotechnical and Hydrodynamic Perspectives

NASA Astrophysics Data System (ADS)

Sassa, S.

2017-12-01

This presentation shows some recent research advances on tsunami-seabed-structure interaction following the 2011 Tohoku Earthquake Tsunami, Japan. It presents a concise summary and discussion of utilizing a geotechnical centrifuge and a large-scale hydro flume for the modelling of tsunami-seabed-structure interaction. I highlight here the role of tsunami-induced seepage in piping/boiling, erosion and bearing capacity decrease and failure of the rubble/seabed foundation. A comparison and discussion are made on the stability assessment for the design of tsunami-resistant structures on the basis of the results from both geo-centrifuge and large-scale hydrodynamic experiments. The concurrent processes of the instability involving the scour of the mound/sandy seabed, bearing capacity failure and flow of the foundation and the failure of caisson breakwaters under tsunami overflow and seepage coupling are made clear in this presentation. Three series of experiments were conducted under fifty gravities. The first series of experiments targeted the instability of the mounds themselves, and the second series of experiments clarified how the mound scour would affect the overall stability of the caissons. The third series of experiments examined the effect of a countermeasure on the basis of the results from the two series of experiments. The experimental results first demonstrated that the coupled overflow-seepage actions promoted the development of the mound scour significantly, and caused bearing capacity failure of the mound, resulting in the total failure of the caisson breakwater, which otherwise remained stable without the coupling effect. The velocity vectors obtained from the high-resolution image analysis illustrated the series of such concurrent scour/bearing-capacity-failure/flow processes leading to the instability of the breakwater. The stability of the breakwaters was significantly improved with decreasing hydraulic gradient underneath the caissons due to an

Acoustic Tomography of the Atmospheric Surface Layer

DTIC Science & Technology

2014-11-28

Report Title Acoustic tomography of the atmospheric surface layer (ASL) is based on the measurements of the travel times of sound propagation between...SECURITY CLASSIFICATION OF: Acoustic tomography of the atmospheric surface layer (ASL) is based on the measurements of the travel times of sound ...organ. In the case of acoustic tomography of the atmospheric surface layer (ASL), the travel times of sound propagation between speakers and

Third International Conference on Acoustic Communication by Animals

DTIC Science & Technology

2011-09-30

communications Invited Speakers Peter Tyack cetacean communications Christopher Clark acoustic environment of whales Whitlow Au sound detection and...echolocation by dolphins Magnus Wahlberg sperm whale acoustics Robert Dooling bird hearing Ronald Hoy communication strategies in insects Peter Narins...frogs (6). Topics covered included cognition/language; song and call classification; rule learning; acoustic ecology; communication in noisy

Formation of Hydro-acoustic Waves in Dissipative Coupled Weakly Compressible Fluids

NASA Astrophysics Data System (ADS)

Abdolali, A.; Kirby, J. T., Jr.; Bellotti, G.

2014-12-01

Recent advances in deep sea measurement technology provide an increasing opportunity to detect and interpret hydro-acoustic waves as a component in improved Tsunami Early Warning Systems (TEWS). For the idealized case of a homogeneous water column above a moving but otherwise rigid bottom (in terms of assessing acoustic wave interaction), the description of the infinite family of acoustic modes is characterized by local water depth at source area; i.e. the period of the first acoustic mode is given by four times the required time for sound to travel from the seabed to the surface. Spreading off from earthquake zone, the dominant spectrum is filtered and enriched by seamounts and barriers. This study focuses on the characteristics of hydro-acoustic waves generated by sudden sea bottom motion in a weakly compressible fluid coupled with an underlying sedimentary layer, where the added complexity of the sediment layer rheology leads to both the lowering of dominant spectral peaks and wave attenuation across the full spectrum. To overcome the computational difficulties of three-dimensional models, we derive a depth integrated equation valid for varying water depth and sediment thickness. Damping behavior of the two layered system is initially taken into account by introducing the viscosity of fluid-like sedimentary layer. We show that low frequency pressure waves which are precursor components of tsunamis contain information of seafloor motion.

Squared exponential covariance function for prediction of hydrocarbon in seabed logging application

NASA Astrophysics Data System (ADS)

Mukhtar, Siti Mariam; Daud, Hanita; Dass, Sarat Chandra

2016-11-01

Seabed Logging technology (SBL) has progressively emerged as one of the demanding technologies in Exploration and Production (E&P) industry. Hydrocarbon prediction in deep water areas is crucial task for a driller in any oil and gas company as drilling cost is very expensive. Simulation data generated by Computer Software Technology (CST) is used to predict the presence of hydrocarbon where the models replicate real SBL environment. These models indicate that the hydrocarbon filled reservoirs are more resistive than surrounding water filled sediments. Then, as hydrocarbon depth is increased, it is more challenging to differentiate data with and without hydrocarbon. MATLAB is used for data extractions for curve fitting process using Gaussian process (GP). GP can be classified into regression and classification problems, where this work only focuses on Gaussian process regression (GPR) problem. Most popular choice to supervise GPR is squared exponential (SE), as it provides stability and probabilistic prediction in huge amounts of data. Hence, SE is used to predict the presence or absence of hydrocarbon in the reservoir from the data generated.

Acoustic Propagation Modeling for Marine Hydro-Kinetic Applications

NASA Astrophysics Data System (ADS)

Johnson, C. N.; Johnson, E.

2014-12-01

The combination of riverine, tidal, and wave energy have the potential to supply over one third of the United States' annual electricity demand. However, in order to deploy and test prototypes, and commercial installations, marine hydrokinetic (MHK) devices must meet strict regulatory guidelines that determine the maximum amount of noise that can be generated and sets particular thresholds for determining disturbance and injury caused by noise. An accurate model for predicting the propagation of a MHK source in a real-life hydro-acoustic environment has been established. This model will help promote the growth and viability of marine, water, and hydrokinetic energy by confidently assuring federal regulations are meet and harmful impacts to marine fish and wildlife are minimal. Paracousti, a finite difference solution to the acoustic equations, was originally developed for sound propagation in atmospheric environments and has been successfully validated for a number of different geophysical activities. The three-dimensional numerical implementation is advantageous over other acoustic propagation techniques for a MHK application where the domains of interest have complex 3D interactions from the seabed, banks, and other shallow water effects. A number of different cases for hydro-acoustic environments have been validated by both analytical and numerical results from canonical and benchmark problems. This includes a variety of hydrodynamic and physical environments that may be present in a potential MHK application including shallow and deep water, sloping, and canyon type bottoms, with varying sound speed and density profiles. With the model successfully validated for hydro-acoustic environments more complex and realistic MHK sources from turbines and/or arrays can be modeled.

Assessing Deep Sea Communities Through Seabed Imagery

NASA Astrophysics Data System (ADS)

Matkin, A. G.; Cross, K.; Milititsky, M.

2016-02-01

The deep sea still remains virtually unexplored. Human activity, such as oil and gas exploration and deep sea mining, is expanding further into the deep sea, increasing the need to survey and map extensive areas of this habitat in order to assess ecosystem health and value. The technology needed to explore this remote environment has been advancing. Seabed imagery can cover extensive areas of the seafloor and investigate areas where sampling with traditional coring methodologies is just not possible (e.g. cold water coral reefs). Remotely operated vehicles (ROVs) are an expensive option, so drop or towed camera systems can provide a more viable and affordable alternative, while still allowing for real-time control. Assessment of seabed imagery in terms of presence, abundance and density of particular species can be conducted by bringing together a variety of analytical tools for a holistic approach. Sixteen deep sea transects located offshore West Africa were investigated with a towed digital video telemetry system (DTS). Both digital stills and video footage were acquired. An extensive data set was obtained from over 13,000 usable photographs, allowing for characterisation of the different habitats present in terms of community composition and abundance. All observed fauna were identified to the lowest taxonomic level and enumerated when possible, with densities derived after the seabed area was calculated for each suitable photograph. This methodology allowed for consistent assessment of the different habitat types present, overcoming constraints, such as specific taxa that cannot be enumerated, such as sponges, corals or bryozoans, the presence of mobile and sessile species, or the level of taxonomic detail. Although this methodology will not enable a full characterisation of a deep sea community, in terms of species composition for instance, itt will allow a robust assessment of large areas of the deep sea in terms of sensitive habitats present and community

Comparison of different classification algorithms for underwater target discrimination.

PubMed

Li, Donghui; Azimi-Sadjadi, Mahmood R; Robinson, Marc

2004-01-01

Classification of underwater targets from the acoustic backscattered signals is considered here. Several different classification algorithms are tested and benchmarked not only for their performance but also to gain insight to the properties of the feature space. Results on a wideband 80-kHz acoustic backscattered data set collected for six different objects are presented in terms of the receiver operating characteristic (ROC) and robustness of the classifiers wrt reverberation.

Acoustic Scattering Classification of Zooplankton and Microstructure

DTIC Science & Technology

2001-09-30

As part of this investigation, we have been observing concentrations of siphonulae, a larval form of the gas-bearing zooplankton siphonophore . The...situ measurements of acoustic target strengths of siphonophores , a gas-bearing zooplankter,” ICES J. Mar. Sci. 58: 740-749. Warren, J.D., T.K

Application of a new genetic classification and semi-automated geomorphic mapping approach in the Perth submarine canyon, Australia

NASA Astrophysics Data System (ADS)

Picard, K.; Nanson, R.; Huang, Z.; Nichol, S.; McCulloch, M.

2017-12-01

The acquisition of high resolution marine geophysical data has intensified in recent years (e.g. multibeam echo-sounding, sub-bottom profiling). This progress provides the opportunity to classify and map the seafloor in greater detail, using new methods that preserve the links between processes and morphology. Geoscience Australia has developed a new genetic classification approach, nested within the Harris et al (2014) global seafloor mapping framework. The approach divides parent units into sub-features based on established classification schemes and feature descriptors defined by Bradwell et al. (2016: http://nora.nerc.ac.uk/), the International Hydrographic Organization (https://www.iho.int) and the Coastal Marine and Ecological Classification Standard (https://www.cmecscatalog.org). Owing to the ecological significance of submarine canyon systems in particular, much recent attention has focused on defining their variation in form and process, whereby they can be classified using a range of topographic metrics, fluvial dis/connection and shelf-incising status. The Perth Canyon is incised into the continental slope and shelf of southwest Australia, covering an area of >1500 km2 and extending from 4700 m water depth to the shelf break in 170 m. The canyon sits within a Marine Protected Area, incorporating a Marine National Park and Habitat Protection Zone in recognition of its benthic and pelagic biodiversity values. However, detailed information of the spatial patterns of the seabed habitats that influence this biodiversity is lacking. Here we use 20 m resolution bathymetry and acoustic backscatter data acquired in 2015 by the Schmidt Ocean Institute plus sub-bottom datasets and sediment samples collected Geoscience Australia in 2005 to apply the new geomorphic classification system to the Perth Canyon. This presentation will show the results of the geomorphic feature mapping of the canyon and its application to better defining potential benthic habitats.

An Annotated Bibliography of Patents Related to Coastal Engineering. Volume I. 1967-1970. Appendix.

DTIC Science & Technology

1979-11-01

HYDRAULIC MODEL BASIN PILE, STRUCTURE CONNECTION ICE PROTECTION PILE, WOOD 16 -- mi • . ... -- POLLUTANT ABSORPTION SEISMIC ACOUSTIC TRANSMITTER ARRAY...NT SEABED PIPELINE PLACEMENT WIND MEASUREMENT SEABED PROPERTY MEASUREMENT WOOD PRESERVATIVE SEABED SCOUR PROTECTION SEABED SITE SURVEY SEABED SOIL...concrete, wood , or thin steel piling to aid driving. PILE EXTRACTOR - A means of removing a pile from the earth. PILE FOOTING - A means of increasing a

A comparison of acoustic and observed sediment classifications as predictor variables for modelling biotope distributions in Galway Bay, Ireland

NASA Astrophysics Data System (ADS)

O'Carroll, Jack P. J.; Kennedy, Robert; Ren, Lei; Nash, Stephen; Hartnett, Michael; Brown, Colin

2017-10-01

The INFOMAR (Integrated Mapping For the Sustainable Development of Ireland's Marine Resource) initiative has acoustically mapped and classified a significant proportion of Ireland's Exclusive Economic Zone (EEZ), and is likely to be an important tool in Ireland's efforts to meet the criteria of the MSFD. In this study, open source and relic data were used in combination with new grab survey data to model EUNIS level 4 biotope distributions in Galway Bay, Ireland. The correct prediction rates of two artificial neural networks (ANNs) were compared to assess the effectiveness of acoustic sediment classifications versus sediments that were visually classified by an expert in the field as predictor variables. To test for autocorrelation between predictor variables the RELATE routine with Spearman rank correlation method was used. Optimal models were derived by iteratively removing predictor variables and comparing the correct prediction rates of each model. The models with the highest correct prediction rates were chosen as optimal. The optimal models each used a combination of salinity (binary; 0 = polyhaline and 1 = euhaline), proximity to reef (binary; 0 = within 50 m and 1 = outside 50 m), depth (continuous; metres) and a sediment descriptor (acoustic or observed) as predictor variables. As the status of benthic habitats is required to be assessed under the MSFD the Ecological Status (ES) of the subtidal sediments of Galway Bay was also assessed using the Infaunal Quality Index. The ANN that used observed sediment classes as predictor variables could correctly predict the distribution of biotopes 67% of the time, compared to 63% for the ANN using acoustic sediment classes. Acoustic sediment ANN predictions were affected by local sediment heterogeneity, and the lack of a mixed sediment class. The all-round poor performance of ANNs is likely to be a result of the temporally variable and sparsely distributed data within the study area.

Seabed ripple morphology and surficial sediment size at the SAX04 experiments near Fort Walton Beach, Florida, fall 2004

USGS Publications Warehouse

Hanes, Daniel M.; Erikson, Li H.; Lescinski, Jamie M.R.; Harney, Jodi N.; Carter, Carissa L.; Hatcher, Gerry A.; Lacy, Jessica R.; Rubin, David M.

2007-01-01

Data presented in this report originates from measurements obtained off the Florida coast (fig. 1) as part of the Sediment Acoustics Experiment (SAX04) and Ripples Department Research Initiative (DRI) (Office of Naval Research (ONR), Critical Benthic Environmental Processes and Modeling, Long Range BAA 04-001, Sept. 10, 2003). The aim of this document is to present methods employed to extract data and the resulting measured ripple characteristics (ripple height, wavelength, and orientation) and seabed grain sizes. Application and analysis of the data with respect to hydro- and morphodynamics will be addressed in subsequent reports. Sediment transport in the coastal region is a complex process involving interactions between flow dynamics, sediments, and bedforms. Sediment type and bed geometry directly influence entrainment of sediments into suspension, and at sites where ripples occur (sand formations on the order of several cm high and less than two meter long wavelengths), the understanding of ripple dynamics is an essential component in improving sediment transport models. To gain a better understanding and ability to predict sediment transport, a field study was undertaken to investigate morphology, orientation, and dynamics of ripples on the seafloor. The data obtained from the field campaign also supports an on-going effort to study the effects of ripples on low grazing acoustic penetration into sandy marine sediments for the detection of objects, such as mines (Jackson and others, 2002).

Effect of seabed roughness on tidal current turbines

NASA Astrophysics Data System (ADS)

Gupta, Vikrant; Wan, Minping

2017-11-01

Tidal current turbines are shown to have potential to generate clean energy for a negligible environmental impact. These devices, however, operate in high to moderate current regions where the flow is highly turbulent. It has been shown in flume tank experiments at IFREMER in Boulogne-Sur-Mer (France) and NAFL in the University of Minnesota (US) that the level of turbulence and boundary layer profile affect a turbine's power output and wake characteristics. A major factor that determines these marine flow characteristics is the seabed roughness. Experiments, however, cannot simulate the high Reynolds number conditions of real marine flows. For that, we rely on numerical simulations. High accuracy numerical methods, such as DNS, of wall-bounded flows are very expensive, where the number of grid-points needed to resolve the flow varies as (Re) 9 / 4 (where Re is the flow Reynolds number). While numerically affordable RANS methods compromise on accuracy. Wall-modelled LES methods, which provide both accuracy and affordability, have been improved tremendously in the recent years. We discuss the application of such numerical methods for studying the effect of seabed roughness on marine flow features and their impact on turbine power output and wake characteristics. NSFC, Project Number 11672123.

Acoustic Scattering Classification of Zooplankton and Microstructure

DTIC Science & Technology

2002-09-30

the scattering in different areas. In some cases, siphonophores dominated the scattering; in other cases, euphausiids were the dominant scatterers...juvenile form of siphonophores ) through the use of BIOMAPER-II acoustics and video systems. Because of their fragility, these organisms are...scattering strength, total biomass, siphonophore abundance, and water temperature, throughout the water column in a one-hour section of a transect

Storm-wave-induced seabed deformation: Results from in situ observation in the Yellow River subaqueous delta

NASA Astrophysics Data System (ADS)

Jia, Y.; Wang, Z. Mr; Liu, X.; Shan, H.

2017-12-01

Submarine landslides move large volumes of sediment and are often hazardous to offshore installations. Current research into submarine landslides mainly relies on marine surveying techniques. In contrast, in situ observations of the submarine landslide process, specifically seabed deformation, are sparse, and therefore restrict our understanding of submarine landslide mechanisms and the establishment of a disaster warning scheme. The submarine landslide monitoring (SLM) system, which has been designed to partly overcome these pitfalls, can monitor storm-wave-induced submarine landslides in situ and over a long time period. The SLM system comprises two parts: (1) a hydrodynamic monitoring tripod for recording hydrodynamic data and (2) a shape accel array for recording seabed deformation at different depths. This study recorded the development of the SLM system and the results of in situ observation in the Yellow River Delta, China, during the boreal winter of 2014-2015. The results show an abrupt small-scale storm-wave-induced seabed shear deformation; the shear interface is in at least 1.5-m depth and the displacement of sediments at 1.23-m depth is more than 13 mm. The performance of the SLM system confirms the feasibility and stability of this approach. Further, the in situ observations, as well as the laboratory tests, helped reveal the profound mechanism of storm-wave-induced seabed deformation.

Classification of acoustic emission signals using wavelets and Random Forests : Application to localized corrosion

NASA Astrophysics Data System (ADS)

Morizet, N.; Godin, N.; Tang, J.; Maillet, E.; Fregonese, M.; Normand, B.

2016-03-01

This paper aims to propose a novel approach to classify acoustic emission (AE) signals deriving from corrosion experiments, even if embedded into a noisy environment. To validate this new methodology, synthetic data are first used throughout an in-depth analysis, comparing Random Forests (RF) to the k-Nearest Neighbor (k-NN) algorithm. Moreover, a new evaluation tool called the alter-class matrix (ACM) is introduced to simulate different degrees of uncertainty on labeled data for supervised classification. Then, tests on real cases involving noise and crevice corrosion are conducted, by preprocessing the waveforms including wavelet denoising and extracting a rich set of features as input of the RF algorithm. To this end, a software called RF-CAM has been developed. Results show that this approach is very efficient on ground truth data and is also very promising on real data, especially for its reliability, performance and speed, which are serious criteria for the chemical industry.

Fatigue Level Estimation of Bill Based on Acoustic Signal Feature by Supervised SOM

NASA Astrophysics Data System (ADS)

Teranishi, Masaru; Omatu, Sigeru; Kosaka, Toshihisa

Fatigued bills have harmful influence on daily operation of Automated Teller Machine(ATM). To make the fatigued bills classification more efficient, development of an automatic fatigued bill classification method is desired. We propose a new method to estimate bending rigidity of bill from acoustic signal feature of banking machines. The estimated bending rigidities are used as continuous fatigue level for classification of fatigued bill. By using the supervised Self-Organizing Map(supervised SOM), we estimate the bending rigidity from only the acoustic energy pattern effectively. The experimental result with real bill samples shows the effectiveness of the proposed method.

An adaptable walking-skid for seabed ROV under strong current disturbance

NASA Astrophysics Data System (ADS)

Si, Jianting; Chin, Chengsiong

2014-09-01

This paper proposed a new concept of an adaptable multi-legged skid design for retro-fitting to a remotely-operated vehicle (ROV) during high tidal current underwater pipeline inspection. The sole reliance on propeller-driven propulsion for ROV is replaced with a proposed low cost biomimetic solution in the form of an attachable hexapod walking skid. The advantage of this adaptable walking skid is the high stability in positioning and endurances to strong current on the seabed environment. The computer simulation flow studies using Solidworks Flow Simulation shown that the skid attachment in different compensation postures caused at least four times increase in overall drag, and negative lift forces on the seabed ROV to achieve a better maneuvering and station keeping under the high current condition (from 0.5 m/s to 5.0 m/s). A graphical user interface is designed to interact with the user during robot-in-the-loop testing and kinematics simulation in the pool.

Seabed Motion During Sediment Density Flows as Recorded by Displaced Man-Made Motion-Recording Boulders and a Heavy Instrument Platform

NASA Astrophysics Data System (ADS)

Gwiazda, R.; Paull, C. K.; Kieft, B.; Bird, L.; Klimov, D.; Herlien, R.; Sherman, A.; McCann, M. P.; Sumner, E.; Talling, P.; Xu, J.; Parsons, D. R.; Maier, K. L.; Barry, J.

2017-12-01

Over a period of 18 months the Coordinated Canyon Experiment documented the passage of at least 15 sediment density flows in Monterey Canyon, offshore California, with an array of moorings and sensors placed from 200 m to 1,850 m water depths. Free-standing `smart' boulders (Benthic Event Detectors, BED) and a 1,000 Kg tripod with an Acoustic Monitoring Transponder (AMT) and a BED attached to it were deployed in the upper canyon to detect seabed motions during sediment density flows. BEDs consist of spheres made of a combination of metal, plastic and syntactic foam ballasted to 2.1 g/cm3 density, containing accelerometers along three orthogonal axes, a time recorder, and a pressure sensor inside a pressure case rated to 500 m water depth. Acceleration of ≥ 0.008 G triggers data collection at a recording rate of 50 Hz until motion stops. Built-in acoustic beacons and modems allow for BEDs to be relocated, and data to be downloaded, even when BEDs are buried in sediment to depths of >1 m. Over the course of the study, depth changes and velocities of 24 BED movements during 9 events were recorded. BEDs moved at the velocity of the propagation of the flows down canyon, as documented by the time of arrival of the flow at successive sensors, but sometimes travelled at lower speeds. Seven movements of the AMT tripod were also recorded. In the largest of these, the heavy AMT tripod was transported over a distance of 4.1 Km. For at least four of these seven motions the AMT temperature record indicates that the movements were initiated while the tripod was buried. In one particular event simultaneous movements of five BEDs over a 100 m depth range indicate that the entire seabed was in motion at the same time over a canyon distance of 3.5 Km. Reconstructions of instrument motions in this event from their internally recorded acceleration data show that the AMT displacement was at the front of the event and had no rotational component. In contrast, free standing BEDs at the

Data-driven automated acoustic analysis of human infant vocalizations using neural network tools.

PubMed

Warlaumont, Anne S; Oller, D Kimbrough; Buder, Eugene H; Dale, Rick; Kozma, Robert

2010-04-01

Acoustic analysis of infant vocalizations has typically employed traditional acoustic measures drawn from adult speech acoustics, such as f(0), duration, formant frequencies, amplitude, and pitch perturbation. Here an alternative and complementary method is proposed in which data-derived spectrographic features are central. 1-s-long spectrograms of vocalizations produced by six infants recorded longitudinally between ages 3 and 11 months are analyzed using a neural network consisting of a self-organizing map and a single-layer perceptron. The self-organizing map acquires a set of holistic, data-derived spectrographic receptive fields. The single-layer perceptron receives self-organizing map activations as input and is trained to classify utterances into prelinguistic phonatory categories (squeal, vocant, or growl), identify the ages at which they were produced, and identify the individuals who produced them. Classification performance was significantly better than chance for all three classification tasks. Performance is compared to another popular architecture, the fully supervised multilayer perceptron. In addition, the network's weights and patterns of activation are explored from several angles, for example, through traditional acoustic measurements of the network's receptive fields. Results support the use of this and related tools for deriving holistic acoustic features directly from infant vocalization data and for the automatic classification of infant vocalizations.

Benthic Community Composition and Seabed Characteristics of a Chukchi Sea Pockmark

NASA Astrophysics Data System (ADS)

MacDonald, I. R.; Bluhm, B.; Iken, K.; Gagaev, S.; Robinson, S.

2005-12-01

Several dozen seafloor features were mapped by Larry Mayer and his colleagues using swath bathymetry during a 2003 cruise with the USCGC HEALY near the eastern edge of the Chukchi Plateau (Chukchi Sea 76.6N, 163.9W). These were sub-circular depressions ranging from approximately 250 to over 1000m in width, with depths of up to 50m below the surrounding seabed, and situated in water depths from 500 to 950m. The origin of these features was undetermined, but one possibility was that they were pockmarks formed as a result of gas or fluid expulsion processes. We report here on benthic sampling undertaken at one of these pockmarks on 18 July 2005, also from USCGC HEALY. This elongated feature had maximum water depth of approximately 940m, was 1200m in maximum width, and was depressed approximately 40m below the surrounding seabed. The ocean in the vicinity of the pockmark was heavily ice-covered, which tightly restricted the ship's mobility during sampling operations. We used an ROV to collect and photograph the benthic epifauna during a 6h transit that crossed from the outside of the pockmark to near the center over a distance of 900m. We used a down-looking digital camera to collect over 800 pictures of the benthos at altitudes of 2 to 3m above the seabed. We also collected three cores with a 25x25cm box corer. Our investigations did not provide any direct evidence for gas or fluid flux through the seabed of this feature. Neither did we see any secondary indications of methane flux such as authigenic carbonates or bacterial mats. The abundance and diversity of benthic epifauna at this station was the highest among 8 stations sampled using similar methods during a 30 day cruise. The ROV observed brittle stars, various types of anemones, shrimps, eel pouts, stalked crinoids, benthic ctenophore (likely new species), burrows and mounts, gooseneck barnacles, mysids. Holothurians (c.f. Peneagone sp.) were the single most abundant group and were often photographed in

Lake bed classification using acoustic data

USGS Publications Warehouse

Yin, Karen K.; Li, Xing; Bonde, John; Richards, Carl; Cholwek, Gary

1998-01-01

As part of our effort to identify the lake bed surficial substrates using remote sensing data, this work designs pattern classifiers by multivariate statistical methods. Probability distribution of the preprocessed acoustic signal is analyzed first. A confidence region approach is then adopted to improve the design of the existing classifier. A technique for further isolation is proposed which minimizes the expected loss from misclassification. The devices constructed are applicable for real-time lake bed categorization. A mimimax approach is suggested to treat more general cases where the a priori probability distribution of the substrate types is unknown. Comparison of the suggested methods with the traditional likelihood ratio tests is discussed.

Age group estimation in free-ranging African elephants based on acoustic cues of low-frequency rumbles

PubMed Central

Stoeger, Angela S.; Zeppelzauer, Matthias; Baotic, Anton

2015-01-01

Animal vocal signals are increasingly used to monitor wildlife populations and to obtain estimates of species occurrence and abundance. In the future, acoustic monitoring should function not only to detect animals, but also to extract detailed information about populations by discriminating sexes, age groups, social or kin groups, and potentially individuals. Here we show that it is possible to estimate age groups of African elephants (Loxodonta africana) based on acoustic parameters extracted from rumbles recorded under field conditions in a National Park in South Africa. Statistical models reached up to 70 % correct classification to four age groups (infants, calves, juveniles, adults) and 95 % correct classification when categorising into two groups (infants/calves lumped into one group versus adults). The models revealed that parameters representing absolute frequency values have the most discriminative power. Comparable classification results were obtained by fully automated classification of rumbles by high-dimensional features that represent the entire spectral envelope, such as MFCC (75 % correct classification) and GFCC (74 % correct classification). The reported results and methods provide the scientific foundation for a future system that could potentially automatically estimate the demography of an acoustically monitored elephant group or population. PMID:25821348

Seabed photographs, sediment texture analyses, and sun-illuminated sea floor topography in the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts

USGS Publications Warehouse

Valentine, Page C.; Gallea, Leslie B.; Blackwood, Dann S.; Twomey, Erin R.

2010-01-01

The U.S. Geological Survey, in collaboration with National Oceanic and Atmospheric Administration's National Marine Sanctuary Program, conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary region from 1993 to 2004. The mapped area is approximately 3,700 km (1,100 nmi) in size and was subdivided into 18 quadrangles. An extensive series of sea-floor maps of the region based on multibeam sonar surveys has been published as paper maps and online in digital format (PDF, EPS, PS). In addition, 2,628 seabed-sediment samples were collected and analyzed and are in the usSEABED: Atlantic Coast Offshore Surficial Sediment Data Release. This report presents for viewing and downloading the more than 10,600 still seabed photographs that were acquired during the project. The digital images are provided in thumbnail, medium (1536 x 1024 pixels), and high (3071 x 2048) resolution. The images can be viewed by quadrangle on the U.S. Geological Survey Woods Hole Coastal and Marine Science Center's photograph database. Photograph metadata are embedded in each image in Exchangeable Image File Format and also provided in spreadsheet format. Published digital topographic maps and descriptive text for seabed features are included here for downloading and serve as context for the photographs. An interactive topographic map for each quadrangle shows locations of photograph stations, and each location is linked to the photograph database. This map also shows stations where seabed sediment was collected for texture analysis; the results of grain-size analysis and associated metadata are presented in spreadsheet format.

Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping

PubMed Central

Augustsson, Per; Karlsen, Jonas T.; Su, Hao-Wei; Bruus, Henrik; Voldman, Joel

2016-01-01

Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells' interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size. PMID:27180912

Iso-acoustic focusing of cells for size-insensitive acousto-mechanical phenotyping.

PubMed

Augustsson, Per; Karlsen, Jonas T; Su, Hao-Wei; Bruus, Henrik; Voldman, Joel

2016-05-16

Mechanical phenotyping of single cells is an emerging tool for cell classification, enabling assessment of effective parameters relating to cells' interior molecular content and structure. Here, we present iso-acoustic focusing, an equilibrium method to analyze the effective acoustic impedance of single cells in continuous flow. While flowing through a microchannel, cells migrate sideways, influenced by an acoustic field, into streams of increasing acoustic impedance, until reaching their cell-type specific point of zero acoustic contrast. We establish an experimental procedure and provide theoretical justifications and models for iso-acoustic focusing. We describe a method for providing a suitable acoustic contrast gradient in a cell-friendly medium, and use acoustic forces to maintain that gradient in the presence of destabilizing forces. Applying this method we demonstrate iso-acoustic focusing of cell lines and leukocytes, showing that acoustic properties provide phenotypic information independent of size.

Evaluation of seabed mapping methods for fine-scale classification of extremely shallow benthic habitats - Application to the Venice Lagoon, Italy

NASA Astrophysics Data System (ADS)

Montereale Gavazzi, G.; Madricardo, F.; Janowski, L.; Kruss, A.; Blondel, P.; Sigovini, M.; Foglini, F.

2016-03-01

Recent technological developments of multibeam echosounder systems (MBES) allow mapping of benthic habitats with unprecedented detail. MBES can now be employed in extremely shallow waters, challenging data acquisition (as these instruments were often designed for deeper waters) and data interpretation (honed on datasets with resolution sometimes orders of magnitude lower). With extremely high-resolution bathymetry and co-located backscatter data, it is now possible to map the spatial distribution of fine scale benthic habitats, even identifying the acoustic signatures of single sponges. In this context, it is necessary to understand which of the commonly used segmentation methods is best suited to account for such level of detail. At the same time, new sampling protocols for precisely geo-referenced ground truth data need to be developed to validate the benthic environmental classification. This study focuses on a dataset collected in a shallow (2-10 m deep) tidal channel of the Lagoon of Venice, Italy. Using 0.05-m and 0.2-m raster grids, we compared a range of classifications, both pixel-based and object-based approaches, including manual, Maximum Likelihood Classifier, Jenks Optimization clustering, textural analysis and Object Based Image Analysis. Through a comprehensive and accurately geo-referenced ground truth dataset, we were able to identify five different classes of the substrate composition, including sponges, mixed submerged aquatic vegetation, mixed detritic bottom (fine and coarse) and unconsolidated bare sediment. We computed estimates of accuracy (namely Overall, User, Producer Accuracies and the Kappa statistic) by cross tabulating predicted and reference instances. Overall, pixel based segmentations produced the highest accuracies and the accuracy assessment is strongly dependent on the number of classes chosen for the thematic output. Tidal channels in the Venice Lagoon are extremely important in terms of habitats and sediment distribution

The impact of floods and storms on the acoustic reflectivity of the inner continental shelf: A modeling assessment

USGS Publications Warehouse

Pratson, Lincoln F.; Hutton, E.W.H.; Kettner, A.J.; Syvitski, J.P.M.; Hill, P.S.; George, D.A.; Milligan, T.G.

2007-01-01

Flood deposition and storm reworking of sediments on the inner shelf can change the mixture of grain sizes on the seabed and thus its porosity, bulk density, bulk compressional velocity and reflectivity. Whether these changes are significant enough to be detectable by repeat sub-bottom sonar surveys, however, is uncertain. Here the question is addressed through numerical modeling. Episodic flooding of a large versus small river over the course of a century are modeled with HYDROTREND using the drainage basin characteristics of the Po and Pescara Rivers (respectively). A similarly long stochastic record of storms offshore of both rivers is simulated from the statistics of a long-term mooring recording of waves in the western Adriatic Sea. These time series are then input to the stratigraphic model SEDFLUX2D, which simulates flood deposition and storm reworking on the inner shelf beyond the river mouths. Finally, annual changes in seabed reflectivity across these shelf regions are computed from bulk densities output by SEDFLUX2D and compressional sound speeds computed from mean seafloor grain size using the analytical model of Buckingham [1997. Theory of acoustic attenuation, dispersion, and pulse propagation in unconsolidated granular materials including marine sediments. Journal of the Acoustical Society of America 102, 2579-2596; 1998. Theory of compressional and shear waves in fluidlike marine sediments. Journal of the Acoustical Society of America 103, 288-299; 2000. Wave propagation, stress relaxation, and grain-tograin shearing in saturated, unconsolidated marine sediments. Journal of the Acoustical Society of America 108, 2796-2815]. The modeling predicts reflectivities that change from 9 dB for muds farther offshore, values that agree with reflectivity measurements for these sediment types. On local scales of ???100 m, however, maximum changes in reflectivity are <0.5 dB. So are most annual changes in reflectivity over all water depths modeled (i.e., 0-35 m

usSEABED: Gulf of Mexico and Caribbean (Puerto Rico and U.S. Virgin Islands) offshore surficial sediment data release

USGS Publications Warehouse

Buczkowski, Brian J.; Reid, Jane A.; Jenkins, Chris J.; Reid, Jamey M.; Williams, S. Jeffress; Flocks, James G.

2006-01-01

Over the past 50 years there has been an explosion in scientific interest, research effort and information gathered on the geologic sedimentary character of the United States continental margin. Data and information from thousands of publications have greatly increased our scientific understanding of the geologic origins of the shelf surface but rarely have those data been combined and integrated. This publication is the first release of the Gulf of Mexico and Caribbean (Puerto Rico and U.S. Virgin Islands) coastal and offshore data from the usSEABED database. The report contains a compilation of published and previously unpublished sediment texture and other geologic data about the sea floor from diverse sources. usSEABED is an innovative database system developed to bring assorted data together in a unified database. The dbSEABED system is used to process the data. Examples of maps displaying attributes such as grain size and sediment color are included. This database contains information that is a scientific foundation for the USGS Marine Aggregate Resources and Processes Assessment and Benthic Habitats projects, and will be useful to the marine science community for other studies of the Gulf of Mexico and Caribbean continental margins. This publication is divided into ten sections: Home, Introduction, Content, usSEABED (data), dbSEABED (processing), Data Catalog, References, Contacts, Acknowledgments and Frequently Asked Questions. Use the navigation bar on the left to navigate to specific sections of this report. Underlined topics throughout the publication are links to more information. Links to specific and detailed information on processing and those to pages outside this report will open in a new browser window.

Development of new exploration tools for seabed mineral resources - Result of R/V YOKOSUKA research cruise YK09-09 -

NASA Astrophysics Data System (ADS)

Harada, M.; Sayanagi, K.; Kasaya, T.; Sawa, T.; Goto, T.; Tada, N.; Ichihara, H.; Asada, M.; Nakajima, T.; Isezaki, N.

2009-12-01

Detailed information on subsurface structure under seafloor is necessary for the estimation of seabed resources such as the hydrothermal deposit and methane hydrate. Although advantages of geophysical exploration near seafloor are expected for the seabed resource survey, efficient method has not been well-established. The authors started a project to develop exploration tools for seabed resources under the financial support of MEXT-Japan. We carry out research and development mainly regarding measurement of the magnetic field with high-resolution and high-sampling rate electric exploration devices with accurately controlled active source signals. Developed tools will be mounted underwater platforms such as deep-tow system, ROV (remotely operated vehicle), and AUV (autonomous undersea vehicle). We carried out the research cruise (vessel: JAMSTEC R/V YOKOSUKA YK09-09, cruise period: 19-29 July 2009, area surveyed: Kumano-nada, off Kii Peninsula, Japan) to investigate the performance of developed equipments for magnetic exploration. We mounted an Overhauser and two flux-gate magnetometers on the deep-tow and the AUV URASHIMA. To inspect the efficiency of equipments, it is better to measure the magnetic anomaly which is caused by known magnetic source. Therefore, we made a magnetic target which is consisted of 50 neodymium magnets. Before the navigation, the magnetic target was put under water and its position was measured by the acoustic method. The depth of target is about 2,050 meters, and the measurement was performed in the circle of a radius of about 300 meters. The vehicles were navigated at heights of 25 meters for AUV, and about 15 meters for deep-tow. Each of underwater navigation was practiced for two times. Both performances were carried out successfully, which means that we detected the significant magnetic anomalies caused by the target. We will be able to estimate three-dimensional distribution of anomalous magnetic field, and the source property of

Automated classification of mouse pup isolation syllables: from cluster analysis to an Excel-based "mouse pup syllable classification calculator".

PubMed

Grimsley, Jasmine M S; Gadziola, Marie A; Wenstrup, Jeffrey J

2012-01-01

Mouse pups vocalize at high rates when they are cold or isolated from the nest. The proportions of each syllable type produced carry information about disease state and are being used as behavioral markers for the internal state of animals. Manual classifications of these vocalizations identified 10 syllable types based on their spectro-temporal features. However, manual classification of mouse syllables is time consuming and vulnerable to experimenter bias. This study uses an automated cluster analysis to identify acoustically distinct syllable types produced by CBA/CaJ mouse pups, and then compares the results to prior manual classification methods. The cluster analysis identified two syllable types, based on their frequency bands, that have continuous frequency-time structure, and two syllable types featuring abrupt frequency transitions. Although cluster analysis computed fewer syllable types than manual classification, the clusters represented well the probability distributions of the acoustic features within syllables. These probability distributions indicate that some of the manually classified syllable types are not statistically distinct. The characteristics of the four classified clusters were used to generate a Microsoft Excel-based mouse syllable classifier that rapidly categorizes syllables, with over a 90% match, into the syllable types determined by cluster analysis.

Modified DCTNet for audio signals classification

NASA Astrophysics Data System (ADS)

Xian, Yin; Pu, Yunchen; Gan, Zhe; Lu, Liang; Thompson, Andrew

2016-10-01

In this paper, we investigate DCTNet for audio signal classification. Its output feature is related to Cohen's class of time-frequency distributions. We introduce the use of adaptive DCTNet (A-DCTNet) for audio signals feature extraction. The A-DCTNet applies the idea of constant-Q transform, with its center frequencies of filterbanks geometrically spaced. The A-DCTNet is adaptive to different acoustic scales, and it can better capture low frequency acoustic information that is sensitive to human audio perception than features such as Mel-frequency spectral coefficients (MFSC). We use features extracted by the A-DCTNet as input for classifiers. Experimental results show that the A-DCTNet and Recurrent Neural Networks (RNN) achieve state-of-the-art performance in bird song classification rate, and improve artist identification accuracy in music data. They demonstrate A-DCTNet's applicability to signal processing problems.

Acoustic and spectral characteristics of young children's fricative productions: A developmental perspective

NASA Astrophysics Data System (ADS)

Nissen, Shawn L.; Fox, Robert Allen

2005-10-01

Scientists have made great strides toward understanding the mechanisms of speech production and perception. However, the complex relationships between the acoustic structures of speech and the resulting psychological percepts have yet to be fully and adequately explained, especially in speech produced by younger children. Thus, this study examined the acoustic structure of voiceless fricatives (/f, θ, s, /sh/) produced by adults and typically developing children from 3 to 6 years of age in terms of multiple acoustic parameters (durations, normalized amplitude, spectral slope, and spectral moments). It was found that the acoustic parameters of spectral slope and variance (commonly excluded from previous studies of child speech) were important acoustic parameters in the differentiation and classification of the voiceless fricatives, with spectral variance being the only measure to separate all four places of articulation. It was further shown that the sibilant contrast between /s/ and /sh/ was less distinguished in children than adults, characterized by a dramatic change in several spectral parameters at approximately five years of age. Discriminant analysis revealed evidence that classification models based on adult data were sensitive to these spectral differences in the five-year-old age group.

76 FR 65180 - Proposed Information Collection; Comment Request; Deep Seabed Mining Exploration Licenses

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-20

... Collection; Comment Request; Deep Seabed Mining Exploration Licenses AGENCY: National Oceanic and Atmospheric... documentation electronically when feasible. III. Data OMB Control Number: 0648-0145. Form Number: None. Type of... information on respondents, including through the use of automated collection techniques or other forms of...

Baseline seabed habitat and biotope mapping for a proposed marine reserve.

PubMed

Lee, Sonny T M; Kelly, Michelle; Langlois, Tim J; Costello, Mark J

2015-01-01

Seabed mapping can quantify the extent of benthic habitats that comprise marine ecosystems, and assess the impact of fisheries on an ecosystem. In this study, the distribution of seabed habitats in a proposed no-take Marine Reserve along the northeast coast of Great Barrier Island, New Zealand, was mapped using underwater video combined with bathymetry and substratum data. As a result of the boundary extending to the 12 nautical mile Territorial Limit, it would have been the largest coastal Marine Reserve in the country. Recreational and commercial fisheries occur in the region and would be expected to affect species' abundance. The seabed of the study area and adjacent coastal waters has been trawled up to five times per year. Benthic communities were grouped by multivariate cluster analysis into four biotope classes; namely (1) shallow water macroalgae Ecklonia sp. and Ulva sp. on rocky substrata (Eck.Ulv); and deeper (2) diverse epifauna of sponges and bryozoans on rocky substrata (Por.Bry), (3) brittle star Amphiura sp. and sea anemone Edwardsia sp. on muddy sand (Amph.Edw), and (4) hydroids on mud (Hyd). In biotopes Por.Bry, Amph.Edw and Hyd, there where boulders and rocks were present, and diverse sponge, bryozoan and coral communities. Fifty species were recorded in the deep water survey including significant numbers of the shallow-water hexactinellid glass sponges Symplectella rowi Dendy, 1924 and Rossella ijimai Dendy, 1924, the giant pipe demosponge Isodictya cavicornuta Dendy, 1924, black corals, and locally endemic gorgonians. The habitats identified in the waters to the northeast of Great Barrier Island are likely to be representative of similar depth ranges in northeast New Zealand. This study provides a baseline of the benthic habitats so that should the area become a Marine Reserve, any habitat change might be related to protection from fishing activities and impacts, such as recovery of epifauna following cessation of trawling. The habitat map may

Applying multibeam sonar and mathematical modeling for mapping seabed substrate and biota of offshore shallows

NASA Astrophysics Data System (ADS)

Herkül, Kristjan; Peterson, Anneliis; Paekivi, Sander

2017-06-01

Both basic science and marine spatial planning are in a need of high resolution spatially continuous data on seabed habitats and biota. As conventional point-wise sampling is unable to cover large spatial extents in high detail, it must be supplemented with remote sensing and modeling in order to fulfill the scientific and management needs. The combined use of in situ sampling, sonar scanning, and mathematical modeling is becoming the main method for mapping both abiotic and biotic seabed features. Further development and testing of the methods in varying locations and environmental settings is essential for moving towards unified and generally accepted methodology. To fill the relevant research gap in the Baltic Sea, we used multibeam sonar and mathematical modeling methods - generalized additive models (GAM) and random forest (RF) - together with underwater video to map seabed substrate and epibenthos of offshore shallows. In addition to testing the general applicability of the proposed complex of techniques, the predictive power of different sonar-based variables and modeling algorithms were tested. Mean depth, followed by mean backscatter, were the most influential variables in most of the models. Generally, mean values of sonar-based variables had higher predictive power than their standard deviations. The predictive accuracy of RF was higher than that of GAM. To conclude, we found the method to be feasible and with predictive accuracy similar to previous studies of sonar-based mapping.

Acoustic⁻Seismic Mixed Feature Extraction Based on Wavelet Transform for Vehicle Classification in Wireless Sensor Networks.

PubMed

Zhang, Heng; Pan, Zhongming; Zhang, Wenna

2018-06-07

An acoustic⁻seismic mixed feature extraction method based on the wavelet coefficient energy ratio (WCER) of the target signal is proposed in this study for classifying vehicle targets in wireless sensor networks. The signal was decomposed into a set of wavelet coefficients using the à trous algorithm, which is a concise method used to implement the wavelet transform of a discrete signal sequence. After the wavelet coefficients of the target acoustic and seismic signals were obtained, the energy ratio of each layer coefficient was calculated as the feature vector of the target signals. Subsequently, the acoustic and seismic features were merged into an acoustic⁻seismic mixed feature to improve the target classification accuracy after the acoustic and seismic WCER features of the target signal were simplified using the hierarchical clustering method. We selected the support vector machine method for classification and utilized the data acquired from a real-world experiment to validate the proposed method. The calculated results show that the WCER feature extraction method can effectively extract the target features from target signals. Feature simplification can reduce the time consumption of feature extraction and classification, with no effect on the target classification accuracy. The use of acoustic⁻seismic mixed features effectively improved target classification accuracy by approximately 12% compared with either acoustic signal or seismic signal alone.

Comparing acoustic measurement data in eastern margin of Sea of Japan and Umitaka Spur

NASA Astrophysics Data System (ADS)

Kondo, M., IV; Aoyama, C.

2017-12-01

Recently, methane hydrate is gaining remarkable attention for the abundant amount in the sea area around Japan, and also for its carbon dioxide emission amount being as little as that of natural resources when being combusted. Two types of methane hydrates are known to exist, depending on the settings. Sand layer type methane hydrate contains sand particles and is extracted mainly in the Pacific Ocean, around 100 to 400m below seafloor. On the other hand, shallow type is found around 100m below seafloor in the Sea of Japan, in clumps, veins, and particles. One of the extraction methods of shallow type methane hydrate observed in the Sea of Japan is the seabed exploration system using acoustic equipment, which Chiharu Aoyama owns patent. Methane plumes often exist in the vicinity of shallow type methane hydrate and these seeping plumes are visualized as images on acoustic instruments such as quantitative echo sounder and multi-beam echo sounder (hereinafter referred to as MBES). These images look like rising beams on monitors and are called gas plumes. Methane hydrate can be explored effectively in the area using this method and it is understood that even when the same plume is examined, backscattering strength data (hereinafter referred as SV) observed using acoustic equipment will not be the same on quantitative echo sounder and MBES. In June 2017, measurement of acoustic data using multi-beam sonar (EM122) and quantitative echo sounder (EA600) were performed onboard DAIICHI KAIYOMARU (KAIYO ENGINEERING CO., LTD) at eastern margin of Sea of Japn and at Umitaka Spur. In this study, author will make comparisons of the acoustic data.

Suppressed Alpha Oscillations Predict Intelligibility of Speech and its Acoustic Details

PubMed Central

Weisz, Nathan

2012-01-01

Modulations of human alpha oscillations (8–13 Hz) accompany many cognitive processes, but their functional role in auditory perception has proven elusive: Do oscillatory dynamics of alpha reflect acoustic details of the speech signal and are they indicative of comprehension success? Acoustically presented words were degraded in acoustic envelope and spectrum in an orthogonal design, and electroencephalogram responses in the frequency domain were analyzed in 24 participants, who rated word comprehensibility after each trial. First, the alpha power suppression during and after a degraded word depended monotonically on spectral and, to a lesser extent, envelope detail. The magnitude of this alpha suppression exhibited an additional and independent influence on later comprehension ratings. Second, source localization of alpha suppression yielded superior parietal, prefrontal, as well as anterior temporal brain areas. Third, multivariate classification of the time–frequency pattern across participants showed that patterns of late posterior alpha power allowed best for above-chance classification of word intelligibility. Results suggest that both magnitude and topography of late alpha suppression in response to single words can indicate a listener's sensitivity to acoustic features and the ability to comprehend speech under adverse listening conditions. PMID:22100354

Computation on free gas seepage and associated seabed pockmark formation

NASA Astrophysics Data System (ADS)

Su, Z.; Cathles, Lawrence M.; Chen, D. F.; Wu, N. Y.

2010-03-01

Seabed pockmarks formed by seepage of subsurface fluids are very commonly located in areas where gas is present in near-surface sediments. Especially, they are widely observed on the seafloor at hydrate regions around the world. In this paper we consider that capillary sealing is the crucial mechanism for gas entrapment, gas escape, and pockmark formation. In the hydrate system, free gas is trapped beneath the hydrate layer. The gas overpressure increases as the gas accumulates beneath the hydrate. the hydrate layer is a capillary seal. Capillary seals have the property that they fail completely when the gas pressure reaches the point that they are invaded by gas. The release of gas is thus episodic and sudden. We imagine in our model that when it occurs the venting gas will push the overlying water upward at increasingly higher velocities as the gas pipe approaches the seafloor. As the water velocity increases, the near surface sediments will become quick at a depth that is a function of the thickness of free gas column under the hydrate seal and the depth of hydrate seal, leaving a pockmark on the seafloor. The model shows that at least a 22-m-thick free gas layer beneath the hydrate at Blake Ridge is needed to form the 4-m-deep pockmark at the seabed.

Use of acoustic classification of sidescan sonar data for mapping benthic habitat in the Northern Channel Islands, California

USGS Publications Warehouse

Cochrane, Guy R.; Lafferty, Kevin D.

2002-01-01

Highly reflective seafloor features imaged by sidescan sonar in nearshore waters off the Northern Channel Islands (California, USA) have been observed in subsequent submersible dives to be areas of thin sand covering bedrock. Adjacent areas of rocky seafloor, suitable as habitat for endangered species of abalone and rockfish, and encrusting organisms, cannot be differentiated from the areas of thin sand on the basis of acoustic backscatter (i.e. grey level) alone. We found second-order textural analysis of sidescan sonar data useful to differentiate the bottom types where data is not degraded by near-range distortion (caused by slant-range and ground-range corrections), and where data is not degraded by far-range signal attenuation. Hand editing based on submersible observations is necessary to completely convert the sidescan sonar image to a bottom character classification map suitable for habitat mapping.

Tsunami generation and associated waves in the water column and seabed due to an asymmetric earthquake motion within an anisotropic substratum

NASA Astrophysics Data System (ADS)

Bagheri, Amirhossein; Greenhalgh, Stewart; Khojasteh, Ali; Rahimian, Mohammad; Attarnejad, Reza

2016-10-01

In this paper, closed-form integral expressions are derived to describe how surface gravity waves (tsunamis) are generated when general asymmetric ground displacement (due to earthquake rupturing), involving both horizontal and vertical components of motion, occurs at arbitrary depth within the interior of an anisotropic subsea solid beneath the ocean. In addition, we compute the resultant hydrodynamic pressure within the seawater and the elastic wavefield within the seabed at any position. The method of potential functions and an integral transform approach, accompanied by a special contour integration scheme, are adopted to handle the equations of motion and produce the numerical results. The formulation accounts for any number of possible acoustic-gravity modes and is valid for both shallow and deep water situations as well as for any focal depth of the earthquake source. Phase and group velocity dispersion curves are developed for surface gravity (tsunami mode), acoustic-gravity, Rayleigh, and Scholte waves. Several asymptotic cases which arise from the general analysis are discussed and compared to existing solutions. The role of effective parameters such as hypocenter location and frequency of excitation is examined and illustrated through several figures which show the propagation pattern in the vertical and horizontal directions. Attention is directed to the unexpected contribution from the horizontal ground motion. The results have important application in several fields such as tsunami hazard prediction, marine seismology, and offshore and coastal engineering. In a companion paper, we examine the effect of ocean stratification on the appearance and character of internal and surface gravity waves.

An Acoustic Study of the Relationships among Neurologic Disease, Dysarthria Type, and Severity of Dysarthria

ERIC Educational Resources Information Center

Kim, Yunjung; Kent, Raymond D.; Weismer, Gary

2011-01-01

Purpose: This study examined acoustic predictors of speech intelligibility in speakers with several types of dysarthria secondary to different diseases and conducted classification analysis solely by acoustic measures according to 3 variables (disease, speech severity, and dysarthria type). Method: Speech recordings from 107 speakers with…

The legal regime for moon resource utilization, with particular emphasis on environmental protection, and comparable solutions adopted for deep seabed activities

NASA Astrophysics Data System (ADS)

Viikari, L.

This paper will examine the resource utilization regime as established by the body of international space law and by the 1979 Moon Treaty in particular, as well as the current problems pertaining to it. A particular area of interest is environmental protection vis-à-vis resource utilization. A potential source of fruitful analogy is provided by the deep seabed mineral utilization regime, as established by the 1982 United Nations Convention on the Law of the Sea, the 1994 New York Agreement amending it, and the recent 2000 Mining Code as the first part of more detailed regulations that will eventually govern exploration for and exploitation of all deep seabed minerals. Such comparison seems advantageous, because several developments in the field of using the space environment are showing obvious similarities with previous developments in the law of the sea regarding deep seabed resource management. The Moon and the deep seabed (and their natural resources) are also the only environs explicitly proclaimed as the common heritage of mankind. On the other hand, both domains are increasingly affected by commercializat ion and privatization, too. A recent new (legally non-binding) instrument for space activities is the 1996 Declaration on International Cooperation in the Exploration and Use of Outer Space for the Benefit and in the Interests of All States, Taking into Particular Account the Needs of Developing Countries. It attempts at an important compromise regarding the Common Heritage provision, offering a means to share benefits while recognizing market principles. These principles very much resemble the previous solutions adopted by the 1994 New York Agreement for the deep seabed. The paper attempts to reflect in particular upon the experience available from such developments.

The effect of call libraries and acoustic filters on the identification of bat echolocation.

PubMed

Clement, Matthew J; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-09-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management

The effect of call libraries and acoustic filters on the identification of bat echolocation

PubMed Central

Clement, Matthew J; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-01-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management

The effect of call libraries and acoustic filters on the identification of bat echolocation

USGS Publications Warehouse

Clement, Matthew; Murray, Kevin L; Solick, Donald I; Gruver, Jeffrey C

2014-01-01

Quantitative methods for species identification are commonly used in acoustic surveys for animals. While various identification models have been studied extensively, there has been little study of methods for selecting calls prior to modeling or methods for validating results after modeling. We obtained two call libraries with a combined 1556 pulse sequences from 11 North American bat species. We used four acoustic filters to automatically select and quantify bat calls from the combined library. For each filter, we trained a species identification model (a quadratic discriminant function analysis) and compared the classification ability of the models. In a separate analysis, we trained a classification model using just one call library. We then compared a conventional model assessment that used the training library against an alternative approach that used the second library. We found that filters differed in the share of known pulse sequences that were selected (68 to 96%), the share of non-bat noises that were excluded (37 to 100%), their measurement of various pulse parameters, and their overall correct classification rate (41% to 85%). Although the top two filters did not differ significantly in overall correct classification rate (85% and 83%), rates differed significantly for some bat species. In our assessment of call libraries, overall correct classification rates were significantly lower (15% to 23% lower) when tested on the second call library instead of the training library. Well-designed filters obviated the need for subjective and time-consuming manual selection of pulses. Accordingly, researchers should carefully design and test filters and include adequate descriptions in publications. Our results also indicate that it may not be possible to extend inferences about model accuracy beyond the training library. If so, the accuracy of acoustic-only surveys may be lower than commonly reported, which could affect ecological understanding or management

A comparative evaluation of piezoelectric sensors for acoustic emission-based impact location estimation and damage classification in composite structures

NASA Astrophysics Data System (ADS)

Uprety, Bibhisha; Kim, Sungwon; Mathews, V. John; Adams, Daniel O.

2015-03-01

Acoustic Emission (AE) based Structural Health Monitoring (SHM) is of great interest for detecting impact damage in composite structures. Within the aerospace industry the need to detect and locate these events, even when no visible damage is present, is important both from the maintenance and design perspectives. In this investigation, four commercially available piezoelectric sensors were evaluated for usage in an AE-based SHM system. Of particular interest was comparing the acoustic response of the candidate piezoelectric sensors for impact location estimations as well as damage classification resulting from the impact in fiber-reinforced composite structures. Sensor assessment was performed based on response signal characterization and performance for active testing at 300 kHz and steel-ball drop testing using both aluminum and carbon/epoxy composite plates. Wave mode velocities calculated from the measured arrival times were found to be in good agreement with predictions obtained using both the Disperse code and finite element analysis. Differences in the relative strength of the received wave modes, the overall signal strengths and signal-to-noise ratios were observed through the use of both active testing as well as passive steel-ball drop testing. Further comparative is focusing on assessing AE sensor performance for use in impact location estimation algorithms as well as detecting and classifying damage produced in composite structures due to impact events.

Supervised classification of continental shelf sediment off western Donegal, Ireland

NASA Astrophysics Data System (ADS)

Monteys, X.; Craven, K.; McCarron, S. G.

2017-12-01

Managing human impacts on marine ecosystems requires natural regions to be identified and mapped over a range of hierarchically nested scales. In recent years (2000-present) the Irish National Seabed Survey (INSS) and Integrated Mapping for the Sustainable Development of Ireland's Marine Resources programme (INFOMAR) (Geological Survey Ireland and Marine Institute collaborations) has provided unprecedented quantities of high quality data on Ireland's offshore territories. The increasing availability of large, detailed digital representations of these environments requires the application of objective and quantitative analyses. This study presents results of a new approach for sea floor sediment mapping based on an integrated analysis of INFOMAR multibeam bathymetric data (including the derivatives of slope and relative position), backscatter data (including derivatives of angular response analysis) and sediment groundtruthing over the continental shelf, west of Donegal. It applies a Geographic-Object-Based Image Analysis software package to provide a supervised classification of the surface sediment. This approach can provide a statistically robust, high resolution classification of the seafloor. Initial results display a differentiation of sediment classes and a reduction in artefacts from previously applied methodologies. These results indicate a methodology that could be used during physical habitat mapping and classification of marine environments.

In-flight fiber optic acoustic emission sensor (FAESense) system for the real time detection, localization, and classification of damage in composite aircraft structures

NASA Astrophysics Data System (ADS)

Mendoza, Edgar; Prohaska, John; Kempen, Connie; Esterkin, Yan; Sun, Sunjian

2013-05-01

Acoustic emission sensing is a leading structural health monitoring technique use for the early warning detection of structural damage associated with impacts, cracks, fracture, and delaminations in advanced materials. Current AE systems based on electronic PZT transducers suffer from various limitations that prevent its wide dynamic use in practical avionics and aerospace applications where weight, size and power are critical for operation. This paper describes progress towards the development of a wireless in-flight distributed fiber optic acoustic emission monitoring system (FAESense™) suitable for the onboard-unattended detection, localization, and classification of damage in avionics and aerospace structures. Fiber optic AE sensors offer significant advantages over its counterpart electronic AE sensors by using a high-density array of micron-size AE transducers distributed and multiplex over long lengths of a standard single mode optical fiber. Immediate SHM applications are found in commercial and military aircraft, helicopters, spacecraft, wind mil turbine blades, and in next generation weapon systems, as well as in the petrochemical and aerospace industries, civil structures, power utilities, and a wide spectrum of other applications.

Identification of Damaged Wheat Kernels and Cracked-Shell Hazelnuts with Impact Acoustics Time-Frequency Patterns

USDA-ARS?s Scientific Manuscript database

A new adaptive time-frequency (t-f) analysis and classification procedure is applied to impact acoustic signals for detecting hazelnuts with cracked shells and three types of damaged wheat kernels. Kernels were dropped onto a steel plate, and the resulting impact acoustic signals were recorded with ...

Fatigue level estimation of monetary bills based on frequency band acoustic signals with feature selection by supervised SOM

NASA Astrophysics Data System (ADS)

Teranishi, Masaru; Omatu, Sigeru; Kosaka, Toshihisa

Fatigued monetary bills adversely affect the daily operation of automated teller machines (ATMs). In order to make the classification of fatigued bills more efficient, the development of an automatic fatigued monetary bill classification method is desirable. We propose a new method by which to estimate the fatigue level of monetary bills from the feature-selected frequency band acoustic energy pattern of banking machines. By using a supervised self-organizing map (SOM), we effectively estimate the fatigue level using only the feature-selected frequency band acoustic energy pattern. Furthermore, the feature-selected frequency band acoustic energy pattern improves the estimation accuracy of the fatigue level of monetary bills by adding frequency domain information to the acoustic energy pattern. The experimental results with real monetary bill samples reveal the effectiveness of the proposed method.

Fault diagnosis of helical gearbox using acoustic signal and wavelets

NASA Astrophysics Data System (ADS)

Pranesh, SK; Abraham, Siju; Sugumaran, V.; Amarnath, M.

2017-05-01

The efficient transmission of power in machines is needed and gears are an appropriate choice. Faults in gears result in loss of energy and money. The monitoring and fault diagnosis are done by analysis of the acoustic and vibrational signals which are generally considered to be unwanted by products. This study proposes the usage of machine learning algorithm for condition monitoring of a helical gearbox by using the sound signals produced by the gearbox. Artificial faults were created and subsequently signals were captured by a microphone. An extensive study using different wavelet transformations for feature extraction from the acoustic signals was done, followed by waveletselection and feature selection using J48 decision tree and feature classification was performed using K star algorithm. Classification accuracy of 100% was obtained in the study

Machine Learning Algorithms for Automatic Classification of Marmoset Vocalizations

PubMed Central

Ribeiro, Sidarta; Pereira, Danillo R.; Papa, João P.; de Albuquerque, Victor Hugo C.

2016-01-01

Automatic classification of vocalization type could potentially become a useful tool for acoustic the monitoring of captive colonies of highly vocal primates. However, for classification to be useful in practice, a reliable algorithm that can be successfully trained on small datasets is necessary. In this work, we consider seven different classification algorithms with the goal of finding a robust classifier that can be successfully trained on small datasets. We found good classification performance (accuracy > 0.83 and F1-score > 0.84) using the Optimum Path Forest classifier. Dataset and algorithms are made publicly available. PMID:27654941

Acoustic signature recognition technique for Human-Object Interactions (HOI) in persistent surveillance systems

NASA Astrophysics Data System (ADS)

Alkilani, Amjad; Shirkhodaie, Amir

2013-05-01

Handling, manipulation, and placement of objects, hereon called Human-Object Interaction (HOI), in the environment generate sounds. Such sounds are readily identifiable by the human hearing. However, in the presence of background environment noises, recognition of minute HOI sounds is challenging, though vital for improvement of multi-modality sensor data fusion in Persistent Surveillance Systems (PSS). Identification of HOI sound signatures can be used as precursors to detection of pertinent threats that otherwise other sensor modalities may miss to detect. In this paper, we present a robust method for detection and classification of HOI events via clustering of extracted features from training of HOI acoustic sound waves. In this approach, salient sound events are preliminary identified and segmented from background via a sound energy tracking method. Upon this segmentation, frequency spectral pattern of each sound event is modeled and its features are extracted to form a feature vector for training. To reduce dimensionality of training feature space, a Principal Component Analysis (PCA) technique is employed to expedite fast classification of test feature vectors, a kd-tree and Random Forest classifiers are trained for rapid classification of training sound waves. Each classifiers employs different similarity distance matching technique for classification. Performance evaluations of classifiers are compared for classification of a batch of training HOI acoustic signatures. Furthermore, to facilitate semantic annotation of acoustic sound events, a scheme based on Transducer Mockup Language (TML) is proposed. The results demonstrate the proposed approach is both reliable and effective, and can be extended to future PSS applications.

Acoustic Cavitation and Bubble Dynamics.

DTIC Science & Technology

1985-06-15

Ultrasound : Chemical, Physical and Biological Effects by Verlag Chemie International, Inc. FORM I47 EDTOO NOV 65 ISOBSOLETE DD , 3 1473 EDITION OF I...SUnclassified S/N 0102- LF-014-6601 SECURITY CLASSIFICATION OF THIS PAGE (When Date Entered) I ULTRASOUND : CHEMICAL, PHYSICAL, AND BIOLOGICAL EFFECTS CHAPTER...stable cavitation. The topic of this chapter, acoustic cavitation, is but one of several possible mechanisms through which ultrasound can interact with a

Bibliography of marine radiation ecology prepared for the Seabed Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultz, V.S.

1980-02-01

References on the effects of ionizing radiation on aquatic organisms have been obtained from a number of sources. Many were obtained from reviews and other publications. Although the primary purpose of preparing this bibliography was to obtain information related to the nuclear wastes Seabed Disposal Biology Program of Sandia Laboratories, freshwater organisms are included as a matter of convenience and also with the belief that such a bibliography would be of interest to a wider audience than that restricted to the Seabed Program. While compilation of a list in an area broad in scope is often somewhat arbitrary, an attemptmore » was made to reference publications that were related to field or laboratory studies of wild species of plants and animals with respect to radiation effects. Complete information concerning each reference are provided without excessive library search. Since one often finds references listed in the literature that are incompletely cited, it was not always possible to locate the reference for verification or completion of the citation. Such references are included where they appeared to be of possible value. When known, a reference is followed with its Nuclear Science Abstract designation, or rarely other abstract sources. Those desiring additional information should check Nuclear Science Abstracts utilizing the abstract number presented or other abstracting sources. In addition, the language of the article, other than English, is given when it is known to me.« less

Baseline seabed habitat and biotope mapping for a proposed marine reserve

PubMed Central

Kelly, Michelle; Langlois, Tim J.; Costello, Mark J.

2015-01-01

Seabed mapping can quantify the extent of benthic habitats that comprise marine ecosystems, and assess the impact of fisheries on an ecosystem. In this study, the distribution of seabed habitats in a proposed no-take Marine Reserve along the northeast coast of Great Barrier Island, New Zealand, was mapped using underwater video combined with bathymetry and substratum data. As a result of the boundary extending to the 12 nautical mile Territorial Limit, it would have been the largest coastal Marine Reserve in the country. Recreational and commercial fisheries occur in the region and would be expected to affect species’ abundance. The seabed of the study area and adjacent coastal waters has been trawled up to five times per year. Benthic communities were grouped by multivariate cluster analysis into four biotope classes; namely (1) shallow water macroalgae Ecklonia sp. and Ulva sp. on rocky substrata (Eck.Ulv); and deeper (2) diverse epifauna of sponges and bryozoans on rocky substrata (Por.Bry), (3) brittle star Amphiura sp. and sea anemone Edwardsia sp. on muddy sand (Amph.Edw), and (4) hydroids on mud (Hyd). In biotopes Por.Bry, Amph.Edw and Hyd, there where boulders and rocks were present, and diverse sponge, bryozoan and coral communities. Fifty species were recorded in the deep water survey including significant numbers of the shallow-water hexactinellid glass sponges Symplectella rowi Dendy, 1924 and Rossella ijimai Dendy, 1924, the giant pipe demosponge Isodictya cavicornuta Dendy, 1924, black corals, and locally endemic gorgonians. The habitats identified in the waters to the northeast of Great Barrier Island are likely to be representative of similar depth ranges in northeast New Zealand. This study provides a baseline of the benthic habitats so that should the area become a Marine Reserve, any habitat change might be related to protection from fishing activities and impacts, such as recovery of epifauna following cessation of trawling. The habitat map

Multi-angle backscatter classification and sub-bottom profiling for improved seafloor characterization

NASA Astrophysics Data System (ADS)

Alevizos, Evangelos; Snellen, Mirjam; Simons, Dick; Siemes, Kerstin; Greinert, Jens

2018-06-01

This study applies three classification methods exploiting the angular dependence of acoustic seafloor backscatter along with high resolution sub-bottom profiling for seafloor sediment characterization in the Eckernförde Bay, Baltic Sea Germany. This area is well suited for acoustic backscatter studies due to its shallowness, its smooth bathymetry and the presence of a wide range of sediment types. Backscatter data were acquired using a Seabeam1180 (180 kHz) multibeam echosounder and sub-bottom profiler data were recorded using a SES-2000 parametric sonar transmitting 6 and 12 kHz. The high density of seafloor soundings allowed extracting backscatter layers for five beam angles over a large part of the surveyed area. A Bayesian probability method was employed for sediment classification based on the backscatter variability at a single incidence angle, whereas Maximum Likelihood Classification (MLC) and Principal Components Analysis (PCA) were applied to the multi-angle layers. The Bayesian approach was used for identifying the optimum number of acoustic classes because cluster validation is carried out prior to class assignment and class outputs are ordinal categorical values. The method is based on the principle that backscatter values from a single incidence angle express a normal distribution for a particular sediment type. The resulting Bayesian classes were well correlated to median grain sizes and the percentage of coarse material. The MLC method uses angular response information from five layers of training areas extracted from the Bayesian classification map. The subsequent PCA analysis is based on the transformation of these five layers into two principal components that comprise most of the data variability. These principal components were clustered in five classes after running an external cluster validation test. In general both methods MLC and PCA, separated the various sediment types effectively, showing good agreement (kappa >0.7) with the Bayesian

Contamination tracer testing with seabed drills: IODP Expedition 357

NASA Astrophysics Data System (ADS)

Orcutt, Beth N.; Bergenthal, Markus; Freudenthal, Tim; Smith, David; Lilley, Marvin D.; Schnieders, Luzie; Green, Sophie; Früh-Green, Gretchen L.

2017-11-01

IODP Expedition 357 utilized seabed drills for the first time in the history of the ocean drilling program, with the aim of collecting intact sequences of shallow mantle core from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This novel drilling approach required the development of a new remote seafloor system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

Sensitivity of Tsunami Waves and Coastal Inundation/Runup to Seabed Displacement Models: Application to the Cascadia Subduction zone

NASA Astrophysics Data System (ADS)

Jalali Farahani, R.; Fitzenz, D. D.; Nyst, M.

2015-12-01

Major components of tsunami hazard modeling include earthquake source characterization, seabed displacement, wave propagation, and coastal inundation/run-up. Accurate modeling of these components is essential to identify the disaster risk exposures effectively, which would be crucial for insurance industry as well as policy makers to have tsunami resistant design of structures and evacuation planning (FEMA, 2008). In this study, the sensitivity and variability of tsunami coastal inundation due to Cascadia megathrust subduction earthquake are studied by considering the different approaches for seabed displacement model. The first approach is the analytical expressions that were proposed by Okada (1985, 1992) for the surface displacements and strains of rectangular sources. The second approach was introduced by Meade (2006) who introduced analytical solutions for calculating displacements, strains, and stresses on triangular sources. In this study, the seabed displacement using triangular representation of geometrically complex fault surfaces is compared with the Okada rectangular representations for the Cascadia subduction zone. In the triangular dislocation algorithm, the displacement is calculated using superposition of two angular dislocations for each of the three triangle legs. The triangular elements could give a better and gap-free representation of the fault surfaces. In addition, the rectangular representation gives large unphysical vertical displacement along the shallow-depth fault edge that generates unrealistic short-wavelength waves. To study the impact of these two different algorithms on the final tsunami inundation, the initial tsunami wave as well as wave propagation and the coastal inundation are simulated. To model the propagation of tsunami waves and coastal inundation, 2D shallow water equations are modeled using the seabed displacement as the initial condition for the numerical model. Tsunami numerical simulation has been performed on high

Acoustic imaging of the Mediterranean water outflowing through the Strait of Gibraltar

NASA Astrophysics Data System (ADS)

Biescas Gorriz, Berta; Carniel, Sandro; Sallarès, Valentí; Rodriguez Ranero, Cesar

2016-04-01

Acoustic imaging of the Mediterranean water outflowing through the Strait of Gibraltar Berta Biescas (1), Sandro Carniel (2) , Valentí Sallarès (3) and Cesar R. Ranero(3) (1) Istituto di Scienze Marine, CNR, Bologna, Italy (2) Istituto di Scienze Marine, CNR, Venice, Italy (3) Institut de Ciències del Mar, CSIC, Barcelona, Spain Acoustic reflectivity acquired with multichannel seismic reflection (MCS) systems allow to detect and explore the thermohaline structure in the ocean with vertical and lateral resolutions in the order of 10 m, covering hundreds of kilometers in the lateral dimension and the full-depth water column. In this work we present a MCS 2D profile that crosses the Strait of Gibraltar, from the Alboran Sea to the internal Gulf of Cadiz (NE Atlantic Ocean). The MCS data was acquired during the Topomed-Gassis Cruise (European Science Foundation TopoEurope), which was carried out on board of the Spanish R/V Sarmiento de Gamboa in October 2011. The strong thermohaline contrast between the Mediterranean water and the Atlantic water, characterizes this area and allows to visualize, with unprecedented resolution, the acoustic reflectivity associated to the dense flow of the Mediterranean water outflowing through the prominent slope of the Strait of Gibraltar. During the first kilometers, the dense flow drops attached to the continental slope until it reaches the buoyancy depth at 700 m. Then, it detaches from the sea floor and continues flowing towards the Atlantic Ocean, occupying the layer at 700-1500 m deep and developing clear staircase layers. The reflectivity images display near seabed reflections that could well correspond to turbidity layers. The XBT data acquired coincident in time and space with the MCS data will help us in the interpretation and analysis of the acoustic data.

Assessment of pollution impact on biological activity and structure of seabed bacterial communities in the Port of Livorno (Italy).

PubMed

Iannelli, Renato; Bianchi, Veronica; Macci, Cristina; Peruzzi, Eleonora; Chiellini, Carolina; Petroni, Giulio; Masciandaro, Grazia

2012-06-01

The main objective of this study was to assess the impact of pollution on seabed bacterial diversity, structure and activity in the Port of Livorno. Samples of seabed sediments taken from five selected sites within the port were subjected to chemical analyses, enzymatic activity detection, bacterial count and biomolecular analysis. Five different statistics were used to correlate the level of contamination with the detected biological indicators. The results showed that the port is mainly contaminated by variable levels of petroleum hydrocarbons and heavy metals, which affect the structure and activity of the bacterial population. Irrespective of pollution levels, the bacterial diversity did not diverge significantly among the assessed sites and samples, and no dominance was observed. The type of impact of hydrocarbons and heavy metals was controversial, thus enforcing the supposition that the structure of the bacterial community is mainly driven by the levels of nutrients. The combined use of chemical and biological essays resulted in an in-depth observation and analysis of the existing links between pollution macro-indicators and biological response of seabed bacterial communities. Copyright © 2012 Elsevier B.V. All rights reserved.

Semi-Automated Classification of Seafloor Data Collected on the Delmarva Inner Shelf

NASA Astrophysics Data System (ADS)

Sweeney, E. M.; Pendleton, E. A.; Brothers, L. L.; Mahmud, A.; Thieler, E. R.

2017-12-01

We tested automated classification methods on acoustic bathymetry and backscatter data collected by the U.S. Geological Survey (USGS) and National Oceanic and Atmospheric Administration (NOAA) on the Delmarva inner continental shelf to efficiently and objectively identify sediment texture and geomorphology. Automated classification techniques are generally less subjective and take significantly less time than manual classification methods. We used a semi-automated process combining unsupervised and supervised classification techniques to characterize seafloor based on bathymetric slope and relative backscatter intensity. Statistical comparison of our automated classification results with those of a manual classification conducted on a subset of the acoustic imagery indicates that our automated method was highly accurate (95% total accuracy and 93% Kappa). Our methods resolve sediment ridges, zones of flat seafloor and areas of high and low backscatter. We compared our classification scheme with mean grain size statistics of samples collected in the study area and found that strong correlations between backscatter intensity and sediment texture exist. High backscatter zones are associated with the presence of gravel and shells mixed with sand, and low backscatter areas are primarily clean sand or sand mixed with mud. Slope classes further elucidate textural and geomorphologic differences in the seafloor, such that steep slopes (>0.35°) with high backscatter are most often associated with the updrift side of sand ridges and bedforms, whereas low slope with high backscatter correspond to coarse lag or shell deposits. Low backscatter and high slopes are most often found on the downdrift side of ridges and bedforms, and low backscatter and low slopes identify swale areas and sand sheets. We found that poor acoustic data quality was the most significant cause of inaccurate classification results, which required additional user input to mitigate. Our method worked well

Segmentation of the spinous process and its acoustic shadow in vertebral ultrasound images.

PubMed

Berton, Florian; Cheriet, Farida; Miron, Marie-Claude; Laporte, Catherine

2016-05-01

Spinal ultrasound imaging is emerging as a low-cost, radiation-free alternative to conventional X-ray imaging for the clinical follow-up of patients with scoliosis. Currently, deformity measurement relies almost entirely on manual identification of key vertebral landmarks. However, the interpretation of vertebral ultrasound images is challenging, primarily because acoustic waves are entirely reflected by bone. To alleviate this problem, we propose an algorithm to segment these images into three regions: the spinous process, its acoustic shadow and other tissues. This method consists, first, in the extraction of several image features and the selection of the most relevant ones for the discrimination of the three regions. Then, using this set of features and linear discriminant analysis, each pixel of the image is classified as belonging to one of the three regions. Finally, the image is segmented by regularizing the pixel-wise classification results to account for some geometrical properties of vertebrae. The feature set was first validated by analyzing the classification results across a learning database. The database contained 107 vertebral ultrasound images acquired with convex and linear probes. Classification rates of 84%, 92% and 91% were achieved for the spinous process, the acoustic shadow and other tissues, respectively. Dice similarity coefficients of 0.72 and 0.88 were obtained respectively for the spinous process and acoustic shadow, confirming that the proposed method accurately segments the spinous process and its acoustic shadow in vertebral ultrasound images. Furthermore, the centroid of the automatically segmented spinous process was located at an average distance of 0.38 mm from that of the manually labeled spinous process, which is on the order of image resolution. This suggests that the proposed method is a promising tool for the measurement of the Spinous Process Angle and, more generally, for assisting ultrasound-based assessment of scoliosis

Investigating trends in acoustics research from 1970-1999.

PubMed

Viator, J A; Pestorius, F M

2001-05-01

Text data mining is a burgeoning field in which new information is extracted from existing text databases. Computational methods are used to compare relationships between database elements to yield new information about the existing data. Text data mining software was used to determine research trends in acoustics for the years 1970, 1980, 1990, and 1999. Trends were indicated by the number of published articles in the categories of acoustics using the Journal of the Acoustical Society of America (JASA) as the article source. Research was classified using a method based on the Physics and Astronomy Classification Scheme (PACS). Research was further subdivided into world regions, including North and South America, Eastern and Western Europe, Asia, Africa, Middle East, and Australia/New Zealand. In order to gauge the use of JASA as an indicator of international acoustics research, three subjects, underwater sound, nonlinear acoustics, and bioacoustics, were further tracked in 1999, using all journals in the INSPEC database. Research trends indicated a shift in emphasis of certain areas, notably underwater sound, audition, and speech. JASA also showed steady growth, with increasing participation by non-US authors, from about 20% in 1970 to nearly 50% in 1999.

Vertical migration of fine-grained sediments from interior to surface of seabed driven by seepage flows-`sub-bottom sediment pump action'

NASA Astrophysics Data System (ADS)

Zhang, Shaotong; Jia, Yonggang; Wen, Mingzheng; Wang, Zhenhao; Zhang, Yaqi; Zhu, Chaoqi; Li, Bowen; Liu, Xiaolei

2017-02-01

A scientific hypothesis is proposed and preliminarily verified in this paper: under the driving of seepage flows, there might be a vertical migration of fine-grained soil particles from interior to surface of seabed, which is defined as `sub-bottom sediment pump action' in this paper. Field experiments were performed twice on the intertidal flat of the Yellow River delta to study this process via both trapping the pumped materials and recording the pore pressures in the substrate. Experimental results are quite interesting as we did observe yellow slurry which is mainly composed of fine-grained soil particles appearing on the seabed surface; seepage gradients were also detected in the intertidal flat, under the action of tides and small wind waves. Preliminary conclusions are that `sediment pump' occurs when seepage force exceeds a certain threshold: firstly, it is big enough to disconnect the soil particles from the soil skeleton; secondly, the degree of seabed fluidization or bioturbation is big enough to provide preferred paths for the detached materials to migrate upwards. Then they would be firstly pumped from interior to the surface of seabed and then easily re-suspended into overlying water column. Influential factors of `sediment pump' are determined as hydrodynamics (wave energy), degree of consolidation, index of bioturbation (permeability) and content of fine-grained materials (sedimentary age). This new perspective of `sediment pump' may provide some implications for the mechanism interpretation of several unclear geological phenomena in the Yellow River delta area.

Acoustical standards in engineering acoustics

NASA Astrophysics Data System (ADS)

Burkhard, Mahlon D.

2004-05-01

The Engineering Acoustics Technical Committee is concerned with the evolution and improvement of acoustical techniques and apparatus, and with the promotion of new applications of acoustics. As cited in the Membership Directory and Handbook (2002), the interest areas include transducers and arrays; underwater acoustic systems; acoustical instrumentation and monitoring; applied sonics, promotion of useful effects, information gathering and transmission; audio engineering; acoustic holography and acoustic imaging; acoustic signal processing (equipment and techniques); and ultrasound and infrasound. Evident connections between engineering and standards are needs for calibration, consistent terminology, uniform presentation of data, reference levels, or design targets for product development. Thus for the acoustical engineer standards are both a tool for practices, for communication, and for comparison of his efforts with those of others. Development of many standards depends on knowledge of the way products are put together for the market place and acoustical engineers provide important input to the development of standards. Acoustical engineers and members of the Engineering Acoustics arm of the Society both benefit from and contribute to the Acoustical Standards of the Acoustical Society.

Mine burial in the seabed of high-turbidity area—Findings of a first experiment

NASA Astrophysics Data System (ADS)

Baeye, Matthias; Fettweis, Michael; Legrand, Sebastien; Dupont, Yves; Van Lancker, Vera

2012-07-01

The seabed of the North Sea is covered with ammunition dating back from World Wars I and II. With increasing human interference (e.g. fisheries, aggregate extraction, harbor related activities), it forms a threat to the safety at sea. In this study, test mines were deployed on a sandy seabed for 3 months to investigate mine burial processes as a function of hydrodynamic and meteorological conditions. The mine experiment was conducted in a shallow (9 m), macrotidal environment characterized by highly turbid waters (yearly and depth-averaged suspended particulate matter concentration of 100 mg l-1). Results showed some variability of the overall mine burial, which corresponded with scouring processes induced by a (sub-) tidal forcing mechanism. The main burial events however were linked to storm-related scouring processes, and subsequent mine roll into the resulting pit. Two storms affecting the mines during the 3-month experiment resulted in enduring increases in burial volume to 60% and 80%, respectively. More cyclic and ephemeral burial and exposure events appear to be linked to the local hydrodynamic regime. During slack tides, suspended sediment settles on the seabed, increasing the burial volume. In between slack tides, sediment is resuspended, decreasing the burial volume. The temporal pattern of this never reported burial mechanism, as measured optically, mimics the cyclicity of the suspended sediment concentration as recorded by ultrasonic signals at a nearby benthic observatory. Given the similarity in response signals at the two sites, we hypothesize that the formation of high-concentrated mud suspensions (HCMS) is a mechanism causing short-term burial and exposure of mines. This short-term burial and exposure increase the chance that mines are 'missed' during tracking surveys. Test mines contribute to our understanding of the settling and erosion of HCMS, and thus shed a light on generic sedimentary processes.

Extensions to the Speech Disorders Classification System (SDCS)

PubMed Central

Shriberg, Lawrence D.; Fourakis, Marios; Hall, Sheryl D.; Karlsson, Heather B.; Lohmeier, Heather L.; McSweeny, Jane L.; Potter, Nancy L.; Scheer-Cohen, Alison R.; Strand, Edythe A.; Tilkens, Christie M.; Wilson, David L.

2010-01-01

This report describes three extensions to a classification system for pediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). Part I describes a classification extension to the SDCS to differentiate motor speech disorders from speech delay and to differentiate among three subtypes of motor speech disorders. Part II describes the Madison Speech Assessment Protocol (MSAP), an approximately two-hour battery of 25 measures that includes 15 speech tests and tasks. Part III describes the Competence, Precision, and Stability Analytics (CPSA) framework, a current set of approximately 90 perceptual- and acoustic-based indices of speech, prosody, and voice used to quantify and classify subtypes of Speech Sound Disorders (SSD). A companion paper, Shriberg, Fourakis, et al. (2010) provides reliability estimates for the perceptual and acoustic data reduction methods used in the SDCS. The agreement estimates in the companion paper support the reliability of SDCS methods and illustrate the complementary roles of perceptual and acoustic methods in diagnostic analyses of SSD of unknown origin. Examples of research using the extensions to the SDCS described in the present report include diagnostic findings for a sample of youth with motor speech disorders associated with galactosemia (Shriberg, Potter, & Strand, 2010) and a test of the hypothesis of apraxia of speech in a group of children with autism spectrum disorders (Shriberg, Paul, Black, & van Santen, 2010). All SDCS methods and reference databases running in the PEPPER (Programs to Examine Phonetic and Phonologic Evaluation Records; [Shriberg, Allen, McSweeny, & Wilson, 2001]) environment will be disseminated without cost when complete. PMID:20831378

Fidelity of Automatic Speech Processing for Adult and Child Talker Classifications.

PubMed

VanDam, Mark; Silbert, Noah H

2016-01-01

Automatic speech processing (ASP) has recently been applied to very large datasets of naturalistically collected, daylong recordings of child speech via an audio recorder worn by young children. The system developed by the LENA Research Foundation analyzes children's speech for research and clinical purposes, with special focus on of identifying and tagging family speech dynamics and the at-home acoustic environment from the auditory perspective of the child. A primary issue for researchers, clinicians, and families using the Language ENvironment Analysis (LENA) system is to what degree the segment labels are valid. This classification study evaluates the performance of the computer ASP output against 23 trained human judges who made about 53,000 judgements of classification of segments tagged by the LENA ASP. Results indicate performance consistent with modern ASP such as those using HMM methods, with acoustic characteristics of fundamental frequency and segment duration most important for both human and machine classifications. Results are likely to be important for interpreting and improving ASP output.

Fidelity of Automatic Speech Processing for Adult and Child Talker Classifications

PubMed Central

2016-01-01

Automatic speech processing (ASP) has recently been applied to very large datasets of naturalistically collected, daylong recordings of child speech via an audio recorder worn by young children. The system developed by the LENA Research Foundation analyzes children's speech for research and clinical purposes, with special focus on of identifying and tagging family speech dynamics and the at-home acoustic environment from the auditory perspective of the child. A primary issue for researchers, clinicians, and families using the Language ENvironment Analysis (LENA) system is to what degree the segment labels are valid. This classification study evaluates the performance of the computer ASP output against 23 trained human judges who made about 53,000 judgements of classification of segments tagged by the LENA ASP. Results indicate performance consistent with modern ASP such as those using HMM methods, with acoustic characteristics of fundamental frequency and segment duration most important for both human and machine classifications. Results are likely to be important for interpreting and improving ASP output. PMID:27529813

INFOMAR, Ireland's National Seabed Mapping Programme; Sharing Valuable Insights.

NASA Astrophysics Data System (ADS)

Judge, M. T.; McGrath, F.; Cullen, S.; Verbruggen, K.

2017-12-01

Following the successful high-resolution deep-sea mapping carried out as part of the Irish National Seabed Survey (INSS), a strategic, long term programme was established: INtegrated mapping FOr the sustainable development of Ireland MArine Resources (INFOMAR). Funded by Ireland's Department of Communication, Climate Action and Environment, INFOMAR comprises a multi-platform approach to completing Ireland's marine mapping, and is a key action in the integrated marine plan, Harnessing Our Ocean Wealth. Co-managed by Geological Survey Ireland and the Marine Institute, the programme has three work strands: Data Acquisition; Data Exchange and Integration; Value Added Exploitation.The Data Acquisition strand includes collection of geological, hydrographic, oceanographic, habitat and heritage datasets that underpin sustainable development and management of Ireland's marine resources. INFOMAR operates a free data policy; data and outputs are delivered online through the Data Exchange and Integration strand. Uses of data and outputs are wide-ranging and multipurpose. In order to address the evolution and diversification of user requirements, further data product development is facilitated through the Value Added Exploitation strand.Ninety percent of Ireland's territory lies offshore. Therefore, strategic national seabed mapping continues to provide critical, high-resolution baseline datasets for numerous economic sectors and societal needs. From these we can glean important geodynamic knowledge of Ireland's vast maritime territory. INFOMAR remains aligned with national and European policies and directives. Exemplified by our commitment to EMODnet, a European Commission funded project that supports the collection, standardisation and sharing of available marine information, data and data products across all European Seas. As EMODnet Geology Minerals leaders we have developed a framework for mapping marine minerals. Furthermore, collaboration with the international research

Scientific Literature Review on the Topic of Monitoring and Modeling Seabed Evolution Rates

DTIC Science & Technology

2014-11-01

measurement techniques Benthic sea-floor characterisation Coastal Mapping/LIDAR Biomass /benthic habitat Climatology XBeach Policy 1.2.2...http://ed.gdr.nrcan.gc.ca/index_e.php On online data base of “Measurements of biomass and productivity of seabed macrobenthic and megabenthic...unknown origin. At one site, long wavelength ripples are present in what is presumed to be sediment composed of broken shells , tidal velocities exceed

Targeted Acoustic Data Processing for Ocean Ecological Studies

NASA Astrophysics Data System (ADS)

Sidorovskaia, N.; Li, K.; Tiemann, C.; Ackleh, A. S.; Tang, T.; Ioup, G. E.; Ioup, J. W.

2015-12-01

The Gulf of Mexico is home to many species of deep diving marine mammals. In recent years several ecological studies have collected large volumes of Passive Acoustic Monitoring (PAM) data to investigate the effects of anthropogenic activities on protected and endangered marine mammal species. To utilize these data to their fullest potential for abundance estimates and habitat preference studies, automated detection and classification algorithms are needed to extract species acoustic encounters from a continuous stream of data. The species which phonate in overlapping frequency bands represent a particular challenge. This paper analyzes the performance of a newly developed automated detector for the classification of beaked whale clicks in the Northern Gulf of Mexico. Current used beaked whale classification algorithms rely heavily on experienced human operator involvement in manually associating potential events with a particular species of beaked whales. Our detection algorithm is two-stage: the detector is triggered when the species-representative phonation band energy exceeds the baseline detection threshold. Then multiple event attributes (temporal click duration, central frequency, frequency band, frequency sweep rate, Choi-Williams distribution shape indices) are measured. An attribute vector is then used to discriminate among different species of beaked whales present in the Gulf of Mexico and Risso's dolphins which were recognized to mask the detections of beaked whales in the case of widely used energy-band detectors. The detector is applied to the PAM data collected by the Littoral Acoustic Demonstration Center to estimate abundance trends of beaked whales in the vicinity of the 2010 oil spill before and after the disaster. This algorithm will allow automated processing with minimal operator involvement for new and archival PAM data. [The research is supported by a BP/GOMRI 2015-2017 consortium grant.

Seabed gamma-ray spectrometry: applications at IAEA-MEL.

PubMed

Osvath, I; Povinec, P P

2001-01-01

The technique of underwater gamma-ray spectrometry has been developed to complement or replace the traditional sampling-sample analysis approach for applications with space-time constraints, e.g. large areas of investigation, emergency response or long-term monitoring. IAEA-MEL has used both high-efficiency NaI(Tl) and high-resolution HPGe spectrometry to investigate contamination with anthropogenic radionuclides in a variety of marine environments. Surveys at the South Pacific nuclear test sites of Mururoa and Fangataufa have been used to guide sampling in areas of high contamination around ground zero points. In the Irish Sea offshore from the Sellafield nuclear reprocessing plant, a gamma-ray survey of seabed sediment was carried out to obtain estimates of the distribution and subsequently, for the inventory of 137Cs in the investigated area.

Measures of voiced frication for automatic classification

NASA Astrophysics Data System (ADS)

Jackson, Philip J. B.; Jesus, Luis M. T.; Shadle, Christine H.; Pincas, Jonathan

2004-05-01

As an approach to understanding the characteristics of the acoustic sources in voiced fricatives, it seems apt to draw on knowledge of vowels and voiceless fricatives, which have been relatively well studied. However, the presence of both phonation and frication in these mixed-source sounds offers the possibility of mutual interaction effects, with variations across place of articulation. This paper examines the acoustic and articulatory consequences of these interactions and explores automatic techniques for finding parametric and statistical descriptions of these phenomena. A reliable and consistent set of such acoustic cues could be used for phonetic classification or speech recognition. Following work on devoicing of European Portuguese voiced fricatives [Jesus and Shadle, in Mamede et al. (eds.) (Springer-Verlag, Berlin, 2003), pp. 1-8]. and the modulating effect of voicing on frication [Jackson and Shadle, J. Acoust. Soc. Am. 108, 1421-1434 (2000)], the present study focuses on three types of information: (i) sequences and durations of acoustic events in VC transitions, (ii) temporal, spectral and modulation measures from the periodic and aperiodic components of the acoustic signal, and (iii) voicing activity derived from simultaneous EGG data. Analysis of interactions observed in British/American English and European Portuguese speech corpora will be compared, and the principal findings discussed.

Continental-shelf Scale Passive Ocean AcousticWaveguide Remote Sensing of Marine Mammals and other Submerged Objects including Detection, Localization, and Classification

NASA Astrophysics Data System (ADS)

Wang, Delin

In this thesis, we develop the basics of the Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) technique for the instantaneous continental-shelf scale detection, localization and species classification of marine mammal vocalizations. POAWRS uses a large-aperture, densely sampled coherent hydrophone array system with orders of magnitude higher array gain to enhance signal-to-noise ratios (SNR) by coherent beamforming, enabling detection of underwater acoustic signals either two orders of magnitude more distant in range or lower in SNR than a single hydrophone. The ability to employ coherent spatial processing of signals with the POAWRS technology significantly improves areal coverage, enabling detection of oceanic sound sources over instantaneous wide areas spanning 100 km or more in diameter. The POAWRS approach was applied to analyze marine mammal vocalizations from diverse species received on a 160-element Office Naval Research Five Octave Research Array (ONR-FORA) deployed during their feeding season in Fall 2006 in the Gulf of Maine. The species-dependent temporal-spatial distribution of marine mammal vocalizations and correlation to the prey fish distributions have been determined. Furthermore, the probability of detection regions, source level distributions and pulse compression gains of the vocalization signals from diverse marine mammal species have been estimated. We also develop an approach for enhancing the angular resolution and improving bearing estimates of acoustic signals received on a coherent hydrophone array with multiple-nested uniformly-spaced subapertures, such as the ONR-FORA, by nonuniform array beamforming. Finally we develop a low-cost non-oil-filled towable prototype hydrophone array that consists of eight hydrophone elements with real-time data acquisition and 100 m tow cable. The approach demonstrated here will be applied in the development of a full 160 element POAWRS-type low-cost coherent hydrophone array system in the future.

Seabed substrates and sedimentation rates of the European Seas - EMODnet-Geology2

NASA Astrophysics Data System (ADS)

Kaskela, Anu; Kotilainen, Aarno; Alanen, Ulla; Stevenson, Alan; Partners, EMODnet Geology 2

2015-04-01

Seas and oceans are important for us. However, increased human activities in marine and coastal areas have altered marine ecosystems worldwide. To ensure sustainable use of marine resources and health of the seas, improved management is needed. The European Union's (EU) Marine Strategy Framework Directive targets to achieve Good Environmental Status (GES) of the EU's marine waters by 2020. However, it has been acknowledged that the poor access to data on the marine environment was a handicap to government decision-making, a barrier to scientific understanding and a break on the economy. The effective management of the broad marine areas requires spatial datasets covering all European marine areas. As a consequence the European Commission adopted the European Marine Observation and Data Network (EMODnet) in 2009 to combine dispersed marine data into publicly available datasets covering broad areas. The second phase of the EMODnet -Geology project started in 2013 and it will run for 3 years. The partnership includes 36 marine organizations from 30 countries. The partners, mainly from the marine departments of the geological surveys of Europe (through the Association of European Geological Surveys - EuroGeoSurveys), aim to assemble marine geological information at a scale of 1:250,000 from all European sea areas (e.g. the White Sea, Baltic Sea, Barents Sea, the Iberian Coast, and the Mediterranean Sea within EU waters). In comparison to the urEMODnet project (2009-2012) the data will be more detailed and aim to cover much larger area. The project includes collecting and harmonizing the first seabed substrate map for the European Seas, as well as data/map showing sedimentation rates at the seabed. The data will be essential not only for geologists but also for others interested in marine sediments like marine managers and habitat mappers. A 1:250,000 GIS layer on seabed substrates will be delivered in the portal, in addition to the existing 1:1 million map layer from

The impacts of Segura River (Spain) channelization on the coastal seabed.

PubMed

Aragonés, L; Pagán, J I; López, M P; García-Barba, J

2016-02-01

Human actions over rivers and coasts have generated great changes along seaboard. In order to know future development of those changes, it is necessary to understand the development of the coast during the past. When there is a complex morphologic system as a result of the combination of natural elements with human construction elements, the study of the abovementioned changes requires a wider perspective than the one provided by traditional two-dimensional methods. Thus, the Geographic Information Systems (GIS) become a suitable tool for that kind of studies. In this work, GIS are used to understand changes in bathymetry, sediments properties and transport, as well as surface variations of plant species occurred in the Segura River mouth (Spain) within a period of 17 years due to the channelization of the river low course. The methodology followed here implies the integration of data coming from different sources and with different formats in a GIS, what allows for a spatial analysis. Results obtained show the grain-size spatial distribution for every period of time studied, as well as bathymetry changes and seabed morphology. It can be concluded that the construction works carried out in the riverbed have affected sediment grain-size in the area. Clays have nearly disappeared and consequently there is a descent of seabed level that affects plant species, such as Posidonia oceanica. Copyright © 2015 Elsevier B.V. All rights reserved.

Acoustic structures in the alarm calls of Gunnison's prairie dogs.

PubMed

Slobodchikoff, C N; Placer, J

2006-05-01

Acoustic structures of sound in Gunnison's prairie dog alarm calls are described, showing how these acoustic structures may encode information about three different predator species (red-tailed hawk-Buteo jamaicensis; domestic dog-Canis familaris; and coyote-Canis latrans). By dividing each alarm call into 25 equal-sized partitions and using resonant frequencies within each partition, commonly occurring acoustic structures were identified as components of alarm calls for the three predators. Although most of the acoustic structures appeared in alarm calls elicited by all three predator species, the frequency of occurrence of these acoustic structures varied among the alarm calls for the different predators, suggesting that these structures encode identifying information for each of the predators. A classification analysis of alarm calls elicited by each of the three predators showed that acoustic structures could correctly classify 67% of the calls elicited by domestic dogs, 73% of the calls elicited by coyotes, and 99% of the calls elicited by red-tailed hawks. The different distributions of acoustic structures associated with alarm calls for the three predator species suggest a duality of function, one of the design elements of language listed by Hockett [in Animal Sounds and Communication, edited by W. E. Lanyon and W. N. Tavolga (American Institute of Biological Sciences, Washington, DC, 1960), pp. 392-430].

Acoustic surface perception from naturally occurring step sounds of a dexterous hexapod robot

NASA Astrophysics Data System (ADS)

Cuneyitoglu Ozkul, Mine; Saranli, Afsar; Yazicioglu, Yigit

2013-10-01

Legged robots that exhibit dynamic dexterity naturally interact with the surface to generate complex acoustic signals carrying rich information on the surface as well as the robot platform itself. However, the nature of a legged robot, which is a complex, hybrid dynamic system, renders the more common approach of model-based system identification impractical. The present paper focuses on acoustic surface identification and proposes a non-model-based analysis and classification approach adopted from the speech processing literature. A novel feature set composed of spectral band energies augmented by their vector time derivatives and time-domain averaged zero crossing rate is proposed. Using a multi-dimensional vector classifier, these features carry enough information to accurately classify a range of commonly occurring indoor and outdoor surfaces without using of any mechanical system model. A comparative experimental study is carried out and classification performance and computational complexity are characterized. Different feature combinations, classifiers and changes in critical design parameters are investigated. A realistic and representative acoustic data set is collected with the robot moving at different speeds on a number of surfaces. The study demonstrates promising performance of this non-model-based approach, even in an acoustically uncontrolled environment. The approach also has good chance of performing in real-time.

Prediction for potential landslide zones using seismic amplitude in Liwan gas field, northern South China Sea

NASA Astrophysics Data System (ADS)

Li, Xishuang; Liu, Baohua; Liu, Lejun; Zheng, Jiewen; Zhou, Songwang; Zhou, Qingjie

2017-12-01

The Liwan (Lw) gas field located in the northern slope of the South China Sea (SCS) is extremely complex for its sea-floor topograghy, which is a huge challenge for the safety of subsea facilities. It is economically impractical to obtain parameters for risk assessment of slope stability through a large amount of sampling over the whole field. The linkage between soil shear strength and seabed peak amplitude derived from 2D/3D seismic data is helpful for understanding the regional slope-instability risk. In this paper, the relationships among seabed peak, acoustic impedance and shear strength of shallow soil in the study area were discussed based on statistical analysis results. We obtained a similar relationship to that obtained in other deep-water areas. There is a positive correlation between seabed peak amplitude and acoustic impedance and an exponential relationship between acoustic impedance and shear strength of sediment. The acoustic impedance is the key factor linking the seismic amplitude and shear strength. Infinite slope stability analysis results indicate the areas have a high potential of shallow landslide on slopes exceeding 15° when the thickness of loose sediments exceeds 8 m in the Lw gas field. Our prediction shows that they are mainly located in the heads and walls of submarine canyons.

Real-Time Speech/Music Classification With a Hierarchical Oblique Decision Tree

DTIC Science & Technology

2008-04-01

REAL-TIME SPEECH/ MUSIC CLASSIFICATION WITH A HIERARCHICAL OBLIQUE DECISION TREE Jun Wang, Qiong Wu, Haojiang Deng, Qin Yan Institute of Acoustics...time speech/ music classification with a hierarchical oblique decision tree. A set of discrimination features in frequency domain are selected...handle signals without discrimination and can not work properly in the existence of multimedia signals. This paper proposes a real-time speech/ music

Understanding Nearshore Processes Of a Large Arctic Delta Using Combined Seabed Mapping, In Situ Observations, Remote Sensing and Modeling

NASA Astrophysics Data System (ADS)

Solomon, S. M.; Couture, N. J.; Forbes, D. L.; Hoque, A.; Jenner, K. A.; Lintern, G.; Mulligan, R. P.; Perrie, W. A.; Stevens, C. W.; Toulany, B.; Whalen, D.

2009-12-01

The Mackenzie River Delta and the adjacent continental shelf in the southeastern Beaufort Sea are known to host significant quantities of hydrocarbons. Recent environmental reviews of proposed hydrocarbon development have highlighted the need for a better understanding of the processes that control sediment transport and coastal stability. Over the past several years field surveys have been undertaken in winter, spring and summer to acquire data on seabed morphology, sediment properties, sea ice, river-ocean interaction and nearshore oceanography. These data are being used to improve conceptual models of nearshore processes and to develop and validate numerical models of waves, circulation and sediment transport. The timing and location of sediment erosion, transport and deposition is complex, driven by a combination of open water season storms and spring floods. Unlike temperate counterparts, the interaction between the Mackenzie River and the Beaufort Sea during spring freshet is mediated by the presence of ice cover. Increasing discharge exceeds the under-ice flow capacity leading to flooding of the ice surface, followed by vortex drainage through the ice and scour of the seabed below (“strudel” drainage and scour). During winter months, nearshore circulation slows beneath a thickening ice canopy. Recent surveys have shown that the low gradient inner shelf is composed of extensive shoals where ice freezes to the seabed and intervening zones which are slightly deeper than the ice is thick. The duration of ice contact with the bed determines the thermal characteristics of the seabed. Analysis of cores shows that the silts comprising the shoals are up to 6 m thick. The predominantly well sorted and cross-laminated nature of the silts at the top of the cores suggests an active delta front environment. Measurements of waves, currents, conductivity, temperature and sediment concentration during spring and late summer have been acquired. During moderate August

Joint deconvolution and classification with applications to passive acoustic underwater multipath.

PubMed

Anderson, Hyrum S; Gupta, Maya R

2008-11-01

This paper addresses the problem of classifying signals that have been corrupted by noise and unknown linear time-invariant (LTI) filtering such as multipath, given labeled uncorrupted training signals. A maximum a posteriori approach to the deconvolution and classification is considered, which produces estimates of the desired signal, the unknown channel, and the class label. For cases in which only a class label is needed, the classification accuracy can be improved by not committing to an estimate of the channel or signal. A variant of the quadratic discriminant analysis (QDA) classifier is proposed that probabilistically accounts for the unknown LTI filtering, and which avoids deconvolution. The proposed QDA classifier can work either directly on the signal or on features whose transformation by LTI filtering can be analyzed; as an example a classifier for subband-power features is derived. Results on simulated data and real Bowhead whale vocalizations show that jointly considering deconvolution with classification can dramatically improve classification performance over traditional methods over a range of signal-to-noise ratios.

Study of acoustic correlates associate with emotional speech

NASA Astrophysics Data System (ADS)

Yildirim, Serdar; Lee, Sungbok; Lee, Chul Min; Bulut, Murtaza; Busso, Carlos; Kazemzadeh, Ebrahim; Narayanan, Shrikanth

2004-10-01

This study investigates the acoustic characteristics of four different emotions expressed in speech. The aim is to obtain detailed acoustic knowledge on how a speech signal is modulated by changes from neutral to a certain emotional state. Such knowledge is necessary for automatic emotion recognition and classification and emotional speech synthesis. Speech data obtained from two semi-professional actresses are analyzed and compared. Each subject produces 211 sentences with four different emotions; neutral, sad, angry, happy. We analyze changes in temporal and acoustic parameters such as magnitude and variability of segmental duration, fundamental frequency and the first three formant frequencies as a function of emotion. Acoustic differences among the emotions are also explored with mutual information computation, multidimensional scaling and acoustic likelihood comparison with normal speech. Results indicate that speech associated with anger and happiness is characterized by longer duration, shorter interword silence, higher pitch and rms energy with wider ranges. Sadness is distinguished from other emotions by lower rms energy and longer interword silence. Interestingly, the difference in formant pattern between [happiness/anger] and [neutral/sadness] are better reflected in back vowels such as /a/(/father/) than in front vowels. Detailed results on intra- and interspeaker variability will be reported.

Can the benefits of physical seabed restoration justify the costs? An assessment of a disused aggregate extraction site off the Thames Estuary, UK.

PubMed

Cooper, Keith; Burdon, Daryl; Atkins, Jonathan P; Weiss, Laura; Somerfield, Paul; Elliott, Michael; Turner, Kerry; Ware, Suzanne; Vivian, Chris

2013-10-15

Physical and biological seabed impacts can persist long after the cessation of marine aggregate dredging. Whilst small-scale experimental studies have shown that it may be possible to mitigate such impacts, it is unclear whether the costs of restoration are justified on an industrial scale. Here we explore this question using a case study off the Thames Estuary, UK. By understanding the nature and scale of persistent impacts, we identify possible techniques to restore the physical properties of the seabed, and the costs and the likelihood of success. An analysis of the ecosystem services and goods/benefits produced by the site is used to determine whether intervention is justified. Whilst a comparison of costs and benefits at this site suggests restoration would not be warranted, the analysis is site-specific. We emphasise the need to better define what is, and is not, an acceptable seabed condition post-dredging. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Acoustic mode coupling induced by shallow water nonlinear internal waves: sensitivity to environmental conditions and space-time scales of internal waves.

PubMed

Colosi, John A

2008-09-01

While many results have been intuited from numerical simulation studies, the precise connections between shallow-water acoustic variability and the space-time scales of nonlinear internal waves (NLIWs) as well as the background environmental conditions have not been clearly established analytically. Two-dimensional coupled mode propagation through NLIWs is examined using a perturbation series solution in which each order n is associated with nth-order multiple scattering. Importantly, the perturbation solution gives resonance conditions that pick out specific NLIW scales that cause coupling, and seabed attenuation is demonstrated to broaden these resonances, fundamentally changing the coupling behavior at low frequency. Sound-speed inhomogeneities caused by internal solitary waves (ISWs) are primarily considered and the dependence of mode coupling on ISW amplitude, range width, depth structure, location relative to the source, and packet characteristics are delineated as a function of acoustic frequency. In addition, it is seen that significant energy transfer to modes with initially low or zero energy involves at least a second order scattering process. Under moderate scattering conditions, comparisons of first order, single scattering theoretical predictions to direct numerical simulation demonstrate the accuracy of the approach for acoustic frequencies upto 400 Hz and for single as well as multiple ISW wave packets.

Contamination Tracer Testing With Seabed Rock Drills: IODP Expedition 357

NASA Astrophysics Data System (ADS)

Orcutt, B.; Bergenthal, M.; Freudenthal, T.; Smith, D. J.; Lilley, M. D.; Schneiders, L.; Fruh-Green, G. L.

2016-12-01

IODP Expedition 357 utilized seabed rock drills for the first time in the history of the ocean drilling program, with the aim of collecting intact core of shallow mantle sequences from the Atlantis Massif to examine serpentinization processes and the deep biosphere. This new drilling approach required the development of a new system for delivering synthetic tracers during drilling to assess for possible sample contamination. Here, we describe this new tracer delivery system, assess the performance of the system during the expedition, provide an overview of the quality of the core samples collected for deep biosphere investigations based on tracer concentrations, and make recommendations for future applications of the system.

A micro-Doppler sonar for acoustic surveillance in sensor networks

NASA Astrophysics Data System (ADS)

Zhang, Zhaonian

Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

Seabed characterization for the development of marine renewable energy on the Pacific margin of Canada

NASA Astrophysics Data System (ADS)

Barrie, J. Vaughn; Conway, Kim W.

2014-07-01

An inventory of Canada's marine renewable energy resources based on numerical modeling of the potential tidal, wave and wind energy has been published that identifies areas with maximum resource potential. However, the inventory does not consider the seabed geological conditions that will control the safe development of seabed installations and cable corridors. The Geological Survey of Canada (Natural Resources Canada) has therefore undertaken an assessment of seafloor geological characteristics and physical environmental parameters that will be encountered during any extensive deployment of marine renewable energy systems for the Pacific offshore of Canada. Here we present an overview of seabed characterization for key sites for each of the three energy types. Narrow passages exiting the Salish Sea near the Canadian boundary with the United States and northwards out of the Strait of Georgia provide very promising sites for tidal generation. Here, elliptical fields of very large subaqueous dunes, from 12 to 28 m in height, present a significant challenge to site development. Along the exposed continental shelf of Vancouver Island focused wave-energy close to shore (40-60 m water depth) offers significant energy potential, but any engineering systems would have to be founded on a seafloor made up of a mobile gravel lag and an extensive boulder pavement. A large wind farm proposed for the Pacific North Coast would be built on an extensive shallow bank that has active sediment transport and a large field of sand ridges that have developed within a macrotidal environment. A significant challenge is providing for a safe seafloor cable corridor of over 100 km that crosses a large subaqueous dune field to connect to the electrical grid on the mainland. These examples show how geoscience has and will provide critical information to project proponents and regulators for the safe development of marine renewable energy.

Acoustic Biometric System Based on Preprocessing Techniques and Linear Support Vector Machines

PubMed Central

del Val, Lara; Izquierdo-Fuente, Alberto; Villacorta, Juan J.; Raboso, Mariano

2015-01-01

Drawing on the results of an acoustic biometric system based on a MSE classifier, a new biometric system has been implemented. This new system preprocesses acoustic images, extracts several parameters and finally classifies them, based on Support Vector Machine (SVM). The preprocessing techniques used are spatial filtering, segmentation—based on a Gaussian Mixture Model (GMM) to separate the person from the background, masking—to reduce the dimensions of images—and binarization—to reduce the size of each image. An analysis of classification error and a study of the sensitivity of the error versus the computational burden of each implemented algorithm are presented. This allows the selection of the most relevant algorithms, according to the benefits required by the system. A significant improvement of the biometric system has been achieved by reducing the classification error, the computational burden and the storage requirements. PMID:26091392

Acoustic Biometric System Based on Preprocessing Techniques and Linear Support Vector Machines.

PubMed

del Val, Lara; Izquierdo-Fuente, Alberto; Villacorta, Juan J; Raboso, Mariano

2015-06-17

Drawing on the results of an acoustic biometric system based on a MSE classifier, a new biometric system has been implemented. This new system preprocesses acoustic images, extracts several parameters and finally classifies them, based on Support Vector Machine (SVM). The preprocessing techniques used are spatial filtering, segmentation-based on a Gaussian Mixture Model (GMM) to separate the person from the background, masking-to reduce the dimensions of images-and binarization-to reduce the size of each image. An analysis of classification error and a study of the sensitivity of the error versus the computational burden of each implemented algorithm are presented. This allows the selection of the most relevant algorithms, according to the benefits required by the system. A significant improvement of the biometric system has been achieved by reducing the classification error, the computational burden and the storage requirements.

Spatial and temporal variability in sediment deposition and seabed character on the Waipaoa River margin, New Zealand

NASA Astrophysics Data System (ADS)

Walsh, J. P.; Corbett, D. R.; Kiker, J. M.; Orpin, A. R.; Hale, R. P.; Ogston, A. S.

2014-09-01

The stratigraphic record is the manifestation of a wide range of processes, interactions and responses to environmental drivers. Understanding the functioning of river sediment dispersal systems is necessary to determine the fate of sediment and associated material in the marine environment and differentiate key influences in the development of the stratigraphic record. To that end, this study uses sediment cores collected on four successive cruises (January, May and September 2010 and February 2011) on the Waipaoa River margin, New Zealand, to provide insight into spatial and temporal variability in sediment deposition and seabed character. The Waipaoa River discharges a large sediment load into an energetic coast that has a complex margin morphology. Several flood and wave events occurred during the study, and sedimentation varied spatially and temporally. X-radiographs and short-lived radioisotopes indicate emplacement of new event layers prior to all cruises. Notable variation in surficial seabed character (grain-size composition, loss-on-ignition percentage) was apparent on the inner shelf (water depths <40 m), but mid-shelf areas and seaward had more homogeneous sediment properties. 7Be inventories indicate variable patterns of deposition related to fluvial and oceanographic conditions prior to cruises. Ephemeral sediment storage occurs on the inner-shelf of Poverty Bay, into which the Waipaoa River discharges directly, and subsequent export and dispersal patterns are linked to the relative timing and size of flood and wave events. Surficial deposits with characteristics of fluid muds and wave-enhanced sediment gravity flows were noted at some (<25 sites total) mid-shelf and shallower sites from all cruises. During the last cruise considerable inter- and intra-site seabed variability occurred in the interbedded river-proximal inner-shelf deposits over spatial scales of less than a few kilometers. Evidence from earlier sidescan data infer that this could be

Wireless acoustic modules for real-time data fusion using asynchronous sniper localization algorithms

NASA Astrophysics Data System (ADS)

Hengy, S.; De Mezzo, S.; Duffner, P.; Naz, P.

2012-11-01

The presence of snipers in modern conflicts leads to high insecurity for the soldiers. In order to improve the soldier's protection against this threat, the French German Research Institute of Saint-Louis (ISL) has been conducting studies in the domain of acoustic localization of shots. Mobile antennas mounted on the soldier's helmet were initially used for real-time detection, classification and localization of sniper shots. It showed good performances in land scenarios, but also in urban scenarios if the array was in the shot corridor, meaning that the microphones first detect the direct wave and then the reflections of the Mach and muzzle waves (15% distance estimation error compared to the actual shooter array distance). Fusing data sent by multiple sensor nodes distributed on the field showed some of the limitations of the technologies that have been implemented in ISL's demonstrators. Among others, the determination of the arrays' orientation was not accurate enough, thereby degrading the performance of data fusion. Some new solutions have been developed in the past year in order to obtain better performance for data fusion. Asynchronous localization algorithms have been developed and post-processed on data measured in both free-field and urban environments with acoustic modules on the line of sight of the shooter. These results are presented in the first part of the paper. The impact of GPS position estimation error is also discussed in the article in order to evaluate the possible use of those algorithms for real-time processing using mobile acoustic nodes. In the frame of ISL's transverse project IMOTEP (IMprovement Of optical and acoustical TEchnologies for the Protection), some demonstrators are developed that will allow real-time asynchronous localization of sniper shots. An embedded detection and classification algorithm is implemented on wireless acoustic modules that send the relevant information to a central PC. Data fusion is then processed and the

Enhancement of the surface methane hydrate-bearing layer based on the specific microorganisms form deep seabed sediment in Japan Sea.

NASA Astrophysics Data System (ADS)

Hata, T.; Yoneda, J.; Yamamoto, K.

2017-12-01

A methane hydrate-bearing layer located near the Japan Sea has been investigated as a new potential energy resource. In this study examined the feasibility of the seabed surface sediment strength located in the Japan Sea improvement technologies for enhancing microbial induced carbonate precipitation (MICP) process. First, the authors cultivated the specific urease production bacterium culture medium from this surface methane hydrate-bearing layer in the seabed (-600m depth) of Japan Sea. After that, two types of the laboratory test (consolidated-drained triaxial tests) were conducted using this specific culture medium from the seabed in the Japan Sea near the Toyama Prefecture and high urease activities bacterium named Bacillus pasteurii. The main outcomes of this research are as follows. 1) Specific culture medium focused on the urease production bacterium can enhancement of the urease activities from the methane hydrate-bearing layer near the Japan Sea side, 2) This specific culture medium can be enhancement of the surface layer strength, 3) The microbial induced carbonate precipitation process can increase the particle size compared to that of the original particles coating the calcite layer surface, 4) The mechanism for increasing the soil strength is based on the addition of cohesion like a cement stabilized soil.

High resolution mapping and classification of oyster habitats in nearshore Louisiana using sidescan sonar

USGS Publications Warehouse

Allen, Y.C.; Wilson, C.A.; Roberts, H.H.; Supan, J.

2005-01-01

Sidescan sonar holds great promise as a tool to quantitatively depict the distribution and extent of benthic habitats in Louisiana's turbid estuaries. In this study, we describe an effective protocol for acoustic sampling in this environment. We also compared three methods of classification in detail: mean-based thresholding, supervised, and unsupervised techniques to classify sidescan imagery into categories of mud and shell. Classification results were compared to ground truth results using quadrat and dredge sampling. Supervised classification gave the best overall result (kappa = 75%) when compared to quadrat results. Classification accuracy was less robust when compared to all dredge samples (kappa = 21-56%), but increased greatly (90-100%) when only dredge samples taken from acoustically homogeneous areas were considered. Sidescan sonar when combined with ground truth sampling at an appropriate scale can be effectively used to establish an accurate substrate base map for both research applications and shellfish management. The sidescan imagery presented here also provides, for the first time, a detailed presentation of oyster habitat patchiness and scale in a productive oyster growing area.

Event identification by acoustic signature recognition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dress, W.B.; Kercel, S.W.

1995-07-01

Many events of interest to the security commnnity produce acoustic emissions that are, in principle, identifiable as to cause. Some obvious examples are gunshots, breaking glass, takeoffs and landings of small aircraft, vehicular engine noises, footsteps (high frequencies when on gravel, very low frequencies. when on soil), and voices (whispers to shouts). We are investigating wavelet-based methods to extract unique features of such events for classification and identification. We also discuss methods of classification and pattern recognition specifically tailored for acoustic signatures obtained by wavelet analysis. The paper is divided into three parts: completed work, work in progress, and futuremore » applications. The completed phase has led to the successful recognition of aircraft types on landing and takeoff. Both small aircraft (twin-engine turboprop) and large (commercial airliners) were included in the study. The project considered the design of a small, field-deployable, inexpensive device. The techniques developed during the aircraft identification phase were then adapted to a multispectral electromagnetic interference monitoring device now deployed in a nuclear power plant. This is a general-purpose wavelet analysis engine, spanning 14 octaves, and can be adapted for other specific tasks. Work in progress is focused on applying the methods previously developed to speaker identification. Some of the problems to be overcome include recognition of sounds as voice patterns and as distinct from possible background noises (e.g., music), as well as identification of the speaker from a short-duration voice sample. A generalization of the completed work and the work in progress is a device capable of classifying any number of acoustic events-particularly quasi-stationary events such as engine noises and voices and singular events such as gunshots and breaking glass. We will show examples of both kinds of events and discuss their recognition likelihood.« less

Acoustic discrimination of Southern Ocean zooplankton

NASA Astrophysics Data System (ADS)

Brierley, Andrew S.; Ward, Peter; Watkins, Jonathan L.; Goss, Catherine

Acoustic surveys in the vicinity of the sub-Antarctic island of South Georgia during a period of exceptionally calm weather revealed the existence of a number of horizontally extensive yet vertically discrete scattering layers in the upper 250 m of the water column. These layers were fished with a Longhurst-Hardy plankton recorder (LHPR) and a multiple-opening 8 m 2 rectangular mid-water trawl (RMT8). Analysis of catches suggested that each scattering layer was composed predominantly of a single species (biovolume>95%) of either the euphausiids Euphausia frigida or Thysanöessa macrura, the hyperiid amphipod Themisto gaudichaudii, or the eucalaniid copepod Rhincalanus gigas. Instrumentation on the nets allowed their trajectories to be reconstructed precisely, and thus catch data to be related directly to the corresponding acoustic signals. Discriminant function analysis of differences between mean volume backscattering strength at 38, 120 and 200 kHz separated echoes originating from each of the dominant scattering layers, and other signals identified as originating from Antarctic krill ( Euphausia superba), with an overall correct classification rate of 77%. Using echo intensity data alone, gathered using hardware commonly employed for fishery acoustics, it is therefore possible to discriminate in situ between several zooplanktonic taxa, taxa which in some instances exhibit similar gross morphological characteristics and have overlapping length- frequency distributions. Acoustic signals from the mysid Antarctomysis maxima could also be discriminated once information on target distribution was considered, highlighting the value of incorporating multiple descriptors of echo characteristics into signal identification procedures. The ability to discriminate acoustically between zooplankton taxa could be applied to provide improved acoustic estimates of species abundance, and to enhance field studies of zooplankton ecology, distribution and species interactions.

[Acoustic information in snoring noises].

PubMed

Janott, C; Schuller, B; Heiser, C

2017-02-01

More than one third of all people snore regularly. Snoring is a common accompaniment of obstructive sleep apnea (OSA) and is often disruptive for the bed partner. This work gives an overview of the history of and state of research on acoustic analysis of snoring for classification of OSA severity, detection of obstructive events, measurement of annoyance, and identification of the sound excitation location. Based on these objectives, searches were conducted in the literature databases PubMed and IEEE Xplore. Publications dealing with the respective objectives according to title and abstract were selected from the search results. A total of 48 publications concerning the above objectives were considered. The limiting factor of many studies is the small number of subjects upon which the analyses are based. Recent research findings show promising results, such that acoustic analysis may find a place in the framework of sleep diagnostics, thus supplementing the recognized standard methods.

Seabed maps showing topography, ruggedness, backscatter intensity, sediment mobility, and the distribution of geologic substrates in Quadrangle 6 of the Stellwagen Bank National Marine Sanctuary Region offshore of Boston, Massachusetts

USGS Publications Warehouse

Valentine, Page C.; Gallea, Leslie B.

2015-11-10

The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration's National Marine Sanctuary Program, has conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary (SBNMS) region since 1993. The area is approximately 3,700 square kilometers (km2) and is subdivided into 18 quadrangles. Seven maps, at a scale of 1:25,000, of quadrangle 6 (211 km2) depict seabed topography, backscatter, ruggedness, geology, substrate mobility, mud content, and areas dominated by fine-grained or coarse-grained sand. Interpretations of bathymetric and seabed backscatter imagery, photographs, video, and grain-size analyses were used to create the geology-based maps. In all, data from 420 stations were analyzed, including sediment samples from 325 locations. The seabed geology map shows the distribution of 10 substrate types ranging from boulder ridges to immobile, muddy sand to mobile, rippled sand. Mapped substrate types are defined on the basis of sediment grain-size composition, surface morphology, sediment layering, the mobility or immobility of substrate surfaces, and water depth range. This map series is intended to portray the major geological elements (substrates, topographic features, processes) of environments within quadrangle 6. Additionally, these maps will be the basis for the study of the ecological requirements of invertebrate and vertebrate species that utilize these substrates and guide seabed management in the region.

Automated aural classification used for inter-species discrimination of cetaceans.

PubMed

Binder, Carolyn M; Hines, Paul C

2014-04-01

Passive acoustic methods are in widespread use to detect and classify cetacean species; however, passive acoustic systems often suffer from large false detection rates resulting from numerous transient sources. To reduce the acoustic analyst workload, automatic recognition methods may be implemented in a two-stage process. First, a general automatic detector is implemented that produces many detections to ensure cetacean presence is noted. Then an automatic classifier is used to significantly reduce the number of false detections and classify the cetacean species. This process requires development of a robust classifier capable of performing inter-species classification. Because human analysts can aurally discriminate species, an automated aural classifier that uses perceptual signal features was tested on a cetacean data set. The classifier successfully discriminated between four species of cetaceans-bowhead, humpback, North Atlantic right, and sperm whales-with 85% accuracy. It also performed well (100% accuracy) for discriminating sperm whale clicks from right whale gunshots. An accuracy of 92% and area under the receiver operating characteristic curve of 0.97 were obtained for the relatively challenging bowhead and humpback recognition case. These results demonstrated that the perceptual features employed by the aural classifier provided powerful discrimination cues for inter-species classification of cetaceans.

Shear wave velocity and attenuation in the upper layer of ocean bottoms from long-range acoustic field measurements.

PubMed

Zhou, Ji-Xun; Zhang, Xue-Zhen

2012-12-01

Several physics-based seabed geoacoustic models (including the Biot theory) predict that compressional wave attenuation α(2) in sandy marine sediments approximately follows quadratic frequency dependence at low frequencies, i.e., α(2)≈kf(n) (dB/m), n=2. A recent paper on broadband geoacoustic inversions from low frequency (LF) field measurements, made at 20 locations around the world, has indicated that the frequency exponent of the effective sound attenuation n≈1.80 in a frequency band of 50-1000 Hz [Zhou et al., J. Acoust. Soc. Am. 125, 2847-2866 (2009)]. Carey and Pierce hypothesize that the discrepancy is due to the inversion models' neglect of shear wave effects [J. Acoust. Soc. Am. 124, EL271-EL277 (2008)]. The broadband geoacoustic inversions assume that the seabottom is an equivalent fluid and sound waves interact with the bottom at small grazing angles. The shear wave velocity and attenuation in the upper layer of ocean bottoms are estimated from the LF field-inverted effective bottom attenuations using a near-grazing bottom reflection expression for the equivalent fluid model, derived by Zhang and Tindle [J. Acoust. Soc. Am. 98, 3391-3396 (1995)]. The resultant shear wave velocity and attenuation are consistent with the SAX99 measurement at 25 Hz and 1000 Hz. The results are helpful for the analysis of shear wave effects on long-range sound propagation in shallow water.

The effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed

NASA Astrophysics Data System (ADS)

Messieh, S. N.; Rowell, T. W.; Peer, D. L.; Cranford, P. J.

1991-08-01

This paper presents an overview of current knowledge on the effects of trawling, dredging and ocean dumping on the eastern Canadian continental shelf seabed. The impact of trawling and dredging for fish and shellfish on marine habitats has recently attracted international attention among fisheries and environmental scientists. In Atlantic Canada, trawling and dredging are the principal methods of harvesting groundfish and scallops and ocean clams, respectively. It is estimated that fish trawlers and scallop dredges have swept tracks, cris-crossing the Canadian continental shelf, approximately 4.3 million km in length in 1985. In the past few years several studies were carried out by scientists from Canada, the United States and Europe to assess the impacts of trawling and dredging but results were inconclusive. Some studies showed physical damage as well as biological effects, whereas others indicated that the adverse effects were not considered to be serious. Fishermen are not the only potential users of the resources of the continental shelf. There is an increasing demand for good-quality sand and gravel aggregate and the ocean seabed is being seen as a possible source. The eastern Canadian continental shelf also exhibits hydrocarbon potential and operational and accidental discharges are an environmental concern. Increased marine transportation and expansion of the fishing fleet have resulted in a greater need for harbour dredging. Dredging and dredge spoil disposal were controlled by the Ocean Dumping Control Act and now the Canadian Environmental Protection Act which places restrictions on the composition of material that can be disposed of in the sea. Nevertheless some harbours contain contaminant concentrations exceeding the maximum allowable limits. It is concluded that the impacts of human activities on the continental shelf seabed environment are inevitable and the long-term effects, while difficult to determine, must be assessed. The sub-lethal effects

Advanced Technologies for Acoustic Monitoring of Bird Populations

DTIC Science & Technology

2009-04-01

Ford and P. Spong. 2000. Dialect change in resident killer whales : implications for vocal learning and cultural transmission. Animal Behaviour 60: 629...network to compare killer whale (Orcinus orca) dialects. Journal of the Acoustical Society of America 105(4): 2499-2507. Deecke, V. B., J. K. B...Murray, S. O., E. Mercado and H. L. Roitblat. 1998. The neural network classification of false killer whale (Pseudorca crassidens) vocalizations

Backscattering from a sandy seabed measured by a calibrated multibeam echosounder in the 190–400 kHz frequency range

NASA Astrophysics Data System (ADS)

Wendelboe, Gorm

2018-06-01

A SeaBat T50 calibration that combines measurements in a test tank with data from numerical models is presented. The calibration is assessed with data obtained from a series of tests conducted over a sandy seabed outside the harbor of Santa Barbara, California (April 2016). The tests include different tone-burst durations, sound pressure levels, and receive gains in order to verify that the estimated seabed backscattering strength (S_b) is invariant to sonar settings. Finally, S_b-estimates obtained in the frequency range from 190 kHz in steps of 10 kHz up to 400 kHz, and for grazing angles from 20° up to 90° in bins of width 5°, are presented. The results are compared with results found in the literature.

Automated classification of dolphin echolocation click types from the Gulf of Mexico.

PubMed

Frasier, Kaitlin E; Roch, Marie A; Soldevilla, Melissa S; Wiggins, Sean M; Garrison, Lance P; Hildebrand, John A

2017-12-01

Delphinids produce large numbers of short duration, broadband echolocation clicks which may be useful for species classification in passive acoustic monitoring efforts. A challenge in echolocation click classification is to overcome the many sources of variability to recognize underlying patterns across many detections. An automated unsupervised network-based classification method was developed to simulate the approach a human analyst uses when categorizing click types: Clusters of similar clicks were identified by incorporating multiple click characteristics (spectral shape and inter-click interval distributions) to distinguish within-type from between-type variation, and identify distinct, persistent click types. Once click types were established, an algorithm for classifying novel detections using existing clusters was tested. The automated classification method was applied to a dataset of 52 million clicks detected across five monitoring sites over two years in the Gulf of Mexico (GOM). Seven distinct click types were identified, one of which is known to be associated with an acoustically identifiable delphinid (Risso's dolphin) and six of which are not yet identified. All types occurred at multiple monitoring locations, but the relative occurrence of types varied, particularly between continental shelf and slope locations. Automatically-identified click types from autonomous seafloor recorders without verifiable species identification were compared with clicks detected on sea-surface towed hydrophone arrays in the presence of visually identified delphinid species. These comparisons suggest potential species identities for the animals producing some echolocation click types. The network-based classification method presented here is effective for rapid, unsupervised delphinid click classification across large datasets in which the click types may not be known a priori.

The acoustic repertoire and behavioural context of the vocalisations of a nocturnal dasyurid, the eastern quoll (Dasyurus viverrinus)

PubMed Central

Dorph, Annalie

2017-01-01

Defining an acoustic repertoire is essential to understanding vocal signalling and communicative interactions within a species. Currently, quantitative and statistical definition is lacking for the vocalisations of many dasyurids, an important group of small to medium-sized marsupials from Australasia that includes the eastern quoll (Dasyurus viverrinus), a species of conservation concern. Beyond generating a better understanding of this species' social interactions, determining an acoustic repertoire will further improve detection rates and inference of vocalisations gathered by automated bioacoustic recorders. Hence, this study investigated eastern quoll vocalisations using objective signal processing techniques to quantitatively analyse spectrograms recorded from 15 different individuals. Recordings were collected in conjunction with observations of the behaviours associated with each vocalisation to develop an acoustic-based behavioural repertoire for the species. Analysis of recordings produced a putative classification of five vocalisation types: Bark, Growl, Hiss, Cp-cp, and Chuck. These were most frequently observed during agonistic encounters between conspecifics, most likely as a graded sequence from Hisses occurring in a warning context through to Growls and finally Barks being given prior to, or during, physical confrontations between individuals. Quantitative and statistical methods were used to objectively establish the accuracy of these five putative call types. A multinomial logistic regression indicated a 97.27% correlation with the perceptual classification, demonstrating support for the five different vocalisation types. This putative classification was further supported by hierarchical cluster analysis and silhouette information that determined the optimal number of clusters to be five. Minor disparity between the objective and perceptual classifications was potentially the result of gradation between vocalisations, or subtle differences present

In situ acoustic and laboratory ultrasonic sound speed and attenuation measured in heterogeneous soft seabed sediments: Eel River shelf, California

USGS Publications Warehouse

Gorgas, T.J.; Wilkens, R.H.; Fu, S.S.; Neil, Frazer L.; Richardson, M.D.; Briggs, K.B.; Lee, H.

2002-01-01

We compared in situ and laboratory velocity and attenuation values measured in seafloor sediments from the shallow water delta of the Eel River, California. This region receives a substantial volume of fluvial sediment that is discharged annually onto the shelf. Additionally, a high input of fluvial sediments during storms generates flood deposits that are characterized by thin beds of variable grain-sizes between the 40- and 90-m isobaths. The main objectives of this study were (1) to investigate signatures of seafloor processes on geoacoustic and physical properties, and (2) to evaluate differences between geoacoustic parameters measured in situ at acoustic (7.5 kHz) and in the laboratory at ultrasonic (400 kHz) frequencies. The in situ acoustic measurements were conducted between 60 and 100 m of water depth. Wet-bulk density and porosity profiles were obtained to 1.15 m below seafloor (m bsf) using gravity cores of the mostly cohesive fine-grained sediments across- and along-shelf. Physical and geoacoustic properties from six selected sites obtained on the Eel margin revealed the following. (1) Sound speed and wet-bulk density strongly correlated in most cases. (2) Sediment compaction with depth generally led to increased sound speed and density, while porosity and in situ attenuation values decreased. (3) Sound speed was higher in coarser- than in finer-grained sediments, on a maximum average by 80 m s-1. (4) In coarse-grained sediments sound speed was higher in the laboratory (1560 m s-1) than in situ (1520 m s-1). In contrast, average ultrasonic and in situ sound speed in fine-grained sediments showed only little differences (both approximately 1480 m s-1). (5) Greater attenuation was commonly measured in the laboratory (0.4 and 0.8 dB m-1 kHz-1) than in situ (0.02 and 0.65 dB m-1 kHz-1), and remained almost constant below 0.4 m bsf. We attributed discrepancies between laboratory ultrasonic and in situ acoustic measurements to a frequency dependence of

European Science Notes Information Bulletin Reports on Current European/ Middle Eastern Science

DTIC Science & Technology

1991-12-01

50 m); innovative acoustic, substances laser, and biosensors; fluxes through the seabed, and . Biological processes real - time measurement of seabed...Woodhouse, Lowestoft, U.K. 4 r ESNIB 91-07 Title Coordinator and Partners FAX Number European River Ocean System (EROS 2000): J.M. Martin, tcole Normale...Athens, Greece; F. Voutsinou, Athens, Greece European River Ocean System (EROS 2000) - J.-M. Martin, Icole Normale Superierre, Montrouge, 33 1 46570497

Flying insect detection and classification with inexpensive sensors.

PubMed

Chen, Yanping; Why, Adena; Batista, Gustavo; Mafra-Neto, Agenor; Keogh, Eamonn

2014-10-15

An inexpensive, noninvasive system that could accurately classify flying insects would have important implications for entomological research, and allow for the development of many useful applications in vector and pest control for both medical and agricultural entomology. Given this, the last sixty years have seen many research efforts devoted to this task. To date, however, none of this research has had a lasting impact. In this work, we show that pseudo-acoustic optical sensors can produce superior data; that additional features, both intrinsic and extrinsic to the insect's flight behavior, can be exploited to improve insect classification; that a Bayesian classification approach allows to efficiently learn classification models that are very robust to over-fitting, and a general classification framework allows to easily incorporate arbitrary number of features. We demonstrate the findings with large-scale experiments that dwarf all previous works combined, as measured by the number of insects and the number of species considered.

Flying Insect Detection and Classification with Inexpensive Sensors

PubMed Central

Chen, Yanping; Why, Adena; Batista, Gustavo; Mafra-Neto, Agenor; Keogh, Eamonn

2014-01-01

An inexpensive, noninvasive system that could accurately classify flying insects would have important implications for entomological research, and allow for the development of many useful applications in vector and pest control for both medical and agricultural entomology. Given this, the last sixty years have seen many research efforts devoted to this task. To date, however, none of this research has had a lasting impact. In this work, we show that pseudo-acoustic optical sensors can produce superior data; that additional features, both intrinsic and extrinsic to the insect’s flight behavior, can be exploited to improve insect classification; that a Bayesian classification approach allows to efficiently learn classification models that are very robust to over-fitting, and a general classification framework allows to easily incorporate arbitrary number of features. We demonstrate the findings with large-scale experiments that dwarf all previous works combined, as measured by the number of insects and the number of species considered. PMID:25350921

Visual classification of feral cat Felis silvestris catus vocalizations

PubMed Central

Owens, Jessica L.; Olsen, Mariana; Fontaine, Amy; Kloth, Christopher; Kershenbaum, Arik

2017-01-01

Abstract Cat vocal behavior, in particular, the vocal and social behavior of feral cats, is poorly understood, as are the differences between feral and fully domestic cats. The relationship between feral cat social and vocal behavior is important because of the markedly different ecology of feral and domestic cats, and enhanced comprehension of the repertoire and potential information content of feral cat calls can provide both better understanding of the domestication and socialization process, and improved welfare for feral cats undergoing adoption. Previous studies have used conflicting classification schemes for cat vocalizations, often relying on onomatopoeic or popular descriptions of call types (e.g., “miow”). We studied the vocalizations of 13 unaltered domestic cats that complied with our behavioral definition used to distinguish feral cats from domestic. A total of 71 acoustic units were extracted and visually analyzed for the construction of a hierarchical classification of vocal sounds, based on acoustic properties. We identified 3 major categories (tonal, pulse, and broadband) that further breakdown into 8 subcategories, and show a high degree of reliability when sounds are classified blindly by independent observers (Fleiss’ Kappa K = 0.863). Due to the limited behavioral contexts in this study, additional subcategories of cat vocalizations may be identified in the future, but our hierarchical classification system allows for the addition of new categories and new subcategories as they are described. This study shows that cat vocalizations are diverse and complex, and provides an objective and reliable classification system that can be used in future studies. PMID:29491992

Visual classification of feral cat Felis silvestris catus vocalizations.

PubMed

Owens, Jessica L; Olsen, Mariana; Fontaine, Amy; Kloth, Christopher; Kershenbaum, Arik; Waller, Sara

2017-06-01

Cat vocal behavior, in particular, the vocal and social behavior of feral cats, is poorly understood, as are the differences between feral and fully domestic cats. The relationship between feral cat social and vocal behavior is important because of the markedly different ecology of feral and domestic cats, and enhanced comprehension of the repertoire and potential information content of feral cat calls can provide both better understanding of the domestication and socialization process, and improved welfare for feral cats undergoing adoption. Previous studies have used conflicting classification schemes for cat vocalizations, often relying on onomatopoeic or popular descriptions of call types (e.g., "miow"). We studied the vocalizations of 13 unaltered domestic cats that complied with our behavioral definition used to distinguish feral cats from domestic. A total of 71 acoustic units were extracted and visually analyzed for the construction of a hierarchical classification of vocal sounds, based on acoustic properties. We identified 3 major categories (tonal, pulse, and broadband) that further breakdown into 8 subcategories, and show a high degree of reliability when sounds are classified blindly by independent observers (Fleiss' Kappa K  = 0.863). Due to the limited behavioral contexts in this study, additional subcategories of cat vocalizations may be identified in the future, but our hierarchical classification system allows for the addition of new categories and new subcategories as they are described. This study shows that cat vocalizations are diverse and complex, and provides an objective and reliable classification system that can be used in future studies.

Acoustics based assessment of respiratory diseases using GMM classification.

PubMed

Mayorga, P; Druzgalski, C; Morelos, R L; Gonzalez, O H; Vidales, J

2010-01-01

The focus of this paper is to present a method utilizing lung sounds for a quantitative assessment of patient health as it relates to respiratory disorders. In order to accomplish this, applicable traditional techniques within the speech processing domain were utilized to evaluate lung sounds obtained with a digital stethoscope. Traditional methods utilized in the evaluation of asthma involve auscultation and spirometry, but utilization of more sensitive electronic stethoscopes, which are currently available, and application of quantitative signal analysis methods offer opportunities of improved diagnosis. In particular we propose an acoustic evaluation methodology based on the Gaussian Mixed Models (GMM) which should assist in broader analysis, identification, and diagnosis of asthma based on the frequency domain analysis of wheezing and crackles.

Acoustic Environment of Admiralty Inlet: Broadband Noise Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jinshan; Deng, Zhiqun; Martinez, Jayson J.

2011-09-30

Admiralty Inlet has been selected as a potential tidal energy site. It is located near shipping lanes, is a highly variable acoustic environment, and is frequented by the highly endangered southern resident killer whale (SRKW). Resolving environmental impacts is the first step to receiving approval to deploy tidal turbines at Admiralty Inlet. Of particular concern is the potential for blade strike or other negative interactions between the SRKW and the tidal turbine. A variety of technologies including passive and active monitoring systems are being considered as potential tools to determine the presence of SRKW in the vicinity of the turbines.more » Broadband noise level measurements are critical for the determination of design and operation specifications of all marine and hydrokinetic energy capture technologies. Acoustic environment data at the proposed site was acquired at different depths using a cabled vertical line array (VLA) with four calibrated hydrophones. The sound pressure level (SPL) power spectrum density was estimated based on the fast Fourier transform. This study describes the first broadband SPL measurements for this site at different depths with frequency ranging from 10 kHz to 480 kHz in combination with other information. To understand the SPL caused by this bedload transport, three different pressure sensors with temperature and conductivity were also assembled on the VLA to measure the conditions at the hydrophone deployment depth. The broadband SPL levels at frequency ranges of 3 kHz to 7 kHz as a function of depth were estimated. Only the hydrophone at an average depth of 40 m showed the strong dependence of SPL with distance from the bottom, which was possibly caused by the cobbles shifting on the seabed. Automatic Identification System data were also studied to understand the SPL measurements.« less

Seabed topography beneath Larsen C Ice Shelf from seismic soundings

NASA Astrophysics Data System (ADS)

Brisbourne, A. M.; Smith, A. M.; King, E. C.; Nicholls, K. W.; Holland, P. R.; Makinson, K.

2014-01-01

Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-ice shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines was collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-ice shelf oceanic circulation may be affected by ice draft and seabed depth. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general < 10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-ice shelf ocean circulation models.

A psychophysical imaging method evidencing auditory cue extraction during speech perception: a group analysis of auditory classification images.

PubMed

Varnet, Léo; Knoblauch, Kenneth; Serniclaes, Willy; Meunier, Fanny; Hoen, Michel

2015-01-01

Although there is a large consensus regarding the involvement of specific acoustic cues in speech perception, the precise mechanisms underlying the transformation from continuous acoustical properties into discrete perceptual units remains undetermined. This gap in knowledge is partially due to the lack of a turnkey solution for isolating critical speech cues from natural stimuli. In this paper, we describe a psychoacoustic imaging method known as the Auditory Classification Image technique that allows experimenters to estimate the relative importance of time-frequency regions in categorizing natural speech utterances in noise. Importantly, this technique enables the testing of hypotheses on the listening strategies of participants at the group level. We exemplify this approach by identifying the acoustic cues involved in da/ga categorization with two phonetic contexts, Al- or Ar-. The application of Auditory Classification Images to our group of 16 participants revealed significant critical regions on the second and third formant onsets, as predicted by the literature, as well as an unexpected temporal cue on the first formant. Finally, through a cluster-based nonparametric test, we demonstrate that this method is sufficiently sensitive to detect fine modifications of the classification strategies between different utterances of the same phoneme.

Improvements to Passive Acoustic Tracking Methods for Marine Mammal Monitoring

DTIC Science & Technology

2016-05-02

separate and associate calls from individual animals . Marine mammal; Passive acoustic monitoring; Localization; Tracking; Multiple source; Sparse array...position and hydrophone timing offset in addition to animal position Almost all marine mammal tracking methods treat animal position as the only unknown...Workshop on Detection, Classification and Localization (DCL) of Marine Mammals). The animals were expected to be relatively close to the surface

The influence of fish feed pellets on the stability of seabed sediment: A laboratory flume investigation

NASA Astrophysics Data System (ADS)

Neumeier, Urs; Friend, Patrick L.; Gangelhof, Uffe; Lunding, Jens; Lundkvist, Morten; Bergamasco, Alessandro; Amos, Carl L.; Flindt, Mogens

2007-11-01

Superfluous fish food settling below fish farms can have a negative impact on the seabed. To aid in the assessment of this impact a series of flume experiments, designed to mimic seabed conditions below a fish farm, was conducted with the aim of examining the effects of fish pellets on the stability of fine sediments. Artificial beds, with varying quantities of fish pellets incorporated both within the sediment matrix and lying on the sediment surface, were allowed to consolidate for different periods of time ranging from 1 to 10 days, and then subjected to erosion experiments. In flume experiments containing fish pellets, a bacterial biofilm developed at the sediment-water interface after a few days. In the control experiments (no fish pellets), a diatom biofilm caused extensive stabilisation of the surface sediment. The erosion experiments showed that the addition of fish pellets reduced the surface erosion threshold by more than 50%. The stability decrease was more pronounced in the experiments with greater amounts of pellets. Evidence of drag reduction due to high suspended sediment concentration was also observed. This phenomenon is discussed and a correction formula is proposed for the effective shear stress experienced by the bed.

Seabed images from Southern Ocean shelf regions off the northern Antarctic Peninsula and in the southeastern Weddell Sea

NASA Astrophysics Data System (ADS)

Piepenburg, Dieter; Buschmann, Alexander; Driemel, Amelie; Grobe, Hannes; Gutt, Julian; Schumacher, Stefanie; Segelken-Voigt, Alexandra; Sieger, Rainer

2017-07-01

Recent advances in underwater imaging technology allow for the gathering of invaluable scientific information on seafloor ecosystems, such as direct in situ views of seabed habitats and quantitative data on the composition, diversity, abundance, and distribution of epibenthic fauna. The imaging approach has been extensively used within the research project DynAMo (Dynamics of Antarctic Marine Shelf Ecosystems) at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research Bremerhaven (AWI), which aimed to comparatively assess the pace and quality of the dynamics of Southern Ocean benthos. Within this framework, epibenthic spatial distribution patterns have been comparatively investigated in two regions in the Atlantic sector of the Southern Ocean: the shelf areas off the northern tip of the Antarctic Peninsula, representing a region with above-average warming of surface waters and sea-ice reduction, and the shelves of the eastern Weddell Sea as an example of a stable high-Antarctic marine environment that is not (yet) affected by climate change. The AWI Ocean Floor Observation System (OFOS) was used to collect seabed imagery during two cruises of the German research vessel Polarstern, ANT-XXIX/3 (PS81) to the Antarctic Peninsula from January to March 2013 and ANT-XXXI/2 (PS96) to the Weddell Sea from December 2015 to February 2016. Here, we report on the image and data collections gathered during these cruises. During PS81, OFOS was successfully deployed at a total of 31 stations at water depths between 29 and 784 m. At most stations, series of 500 to 530 pictures ( > 15 000 in total, each depicting a seabed area of approximately 3.45 m2 or 2.3 × 1.5 m) were taken along transects approximately 3.7 km in length. During PS96, OFOS was used at a total of 13 stations at water depths between 200 and 754 m, yielding series of 110 to 293 photos (2670 in total) along transects 0.9 to 2.6 km in length. All seabed images taken during the two cruises

Varying acoustic-phonemic ambiguity reveals that talker normalization is obligatory in speech processing.

PubMed

Choi, Ja Young; Hu, Elly R; Perrachione, Tyler K

2018-04-01

The nondeterministic relationship between speech acoustics and abstract phonemic representations imposes a challenge for listeners to maintain perceptual constancy despite the highly variable acoustic realization of speech. Talker normalization facilitates speech processing by reducing the degrees of freedom for mapping between encountered speech and phonemic representations. While this process has been proposed to facilitate the perception of ambiguous speech sounds, it is currently unknown whether talker normalization is affected by the degree of potential ambiguity in acoustic-phonemic mapping. We explored the effects of talker normalization on speech processing in a series of speeded classification paradigms, parametrically manipulating the potential for inconsistent acoustic-phonemic relationships across talkers for both consonants and vowels. Listeners identified words with varying potential acoustic-phonemic ambiguity across talkers (e.g., beet/boat vs. boot/boat) spoken by single or mixed talkers. Auditory categorization of words was always slower when listening to mixed talkers compared to a single talker, even when there was no potential acoustic ambiguity between target sounds. Moreover, the processing cost imposed by mixed talkers was greatest when words had the most potential acoustic-phonemic overlap across talkers. Models of acoustic dissimilarity between target speech sounds did not account for the pattern of results. These results suggest (a) that talker normalization incurs the greatest processing cost when disambiguating highly confusable sounds and (b) that talker normalization appears to be an obligatory component of speech perception, taking place even when the acoustic-phonemic relationships across sounds are unambiguous.

Innovative Acoustic Sensor Technologies for Leak Detection in Challenging Pipe Types

DTIC Science & Technology

2016-12-30

correlation features to detect and pinpoint leaks in challenging pipe types, as well as metallic pipes. 15. SUBJECT TERMS Leak detection; acoustic... correlation ; water distribution systems 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18.NUMBER OF PAGES 109 19a. NAME OF...6 1.3.2 State Regulations and Voluntary Water Industry Standards .......................... 7 2.0 TECHNOLOGY DESCRIPTION

Monitoring of leaked CO2 through sediment, water column and atmosphere in sub-seabed CCS experiment

NASA Astrophysics Data System (ADS)

Shitashima, K.; Sakamoto, A.; Maea, Y.

2013-12-01

CO2 capture and storage in sub-seabed geological formations (sub-seabed CCS) is currently being studied as a feasible option to mitigate the accumulation of anthropogenic CO2 in the atmosphere. In implementing sub-seabed CCS, detecting and monitoring the impact of the sequestered CO2 on the ocean environment is highly important. The first controlled CO2 release experiment, entitled 'Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS)', took place in Ardmucknish Bay, Oban, in May-July 2012. We applied the in-situ pH/pCO2/ORP sensor to the QICS experiment for detection and monitoring of leaked CO2, and carried out several observations. The on-line sensor that was connected by 400m of RS422 cable was deployed close to the CO2 leakage (bubbling) point, and the fluctuations of pH, pCO2 and ORP were monitored in real-time in a observation van on land. Three sets of off-line sensors were also placed on seafloor in respective points (release point, and two low impacted regions at 25m and 75m distant) for three months. The long-term monitoring of pH in sediment at 50cm depth under the seafloor was conducted. The spear type electrode was stabbed into sediment by diver near the CO2 leakage point. Wide-area mapping surveys of pH, pCO2 and ORP in seawater around the leakage point were carried out by AUV (REMUS-100) that some chemical sensors were installed in. The AUV cruised along the grid line in two layers of 4m and 2m above the seafloor during both of periods of low tide and high tide. Atmospheric CO2 in sea surface above the leakage point was observed by the LI-COR CO2 Analyzer. The analyzer was attached to the bow of ship, and the ship navigated a wide-area along a grid observation line during both of periods of low tide and high tide.

A tool for urban soundscape evaluation applying Support Vector Machines for developing a soundscape classification model.

PubMed

Torija, Antonio J; Ruiz, Diego P; Ramos-Ridao, Angel F

2014-06-01

To ensure appropriate soundscape management in urban environments, the urban-planning authorities need a range of tools that enable such a task to be performed. An essential step during the management of urban areas from a sound standpoint should be the evaluation of the soundscape in such an area. In this sense, it has been widely acknowledged that a subjective and acoustical categorization of a soundscape is the first step to evaluate it, providing a basis for designing or adapting it to match people's expectations as well. In this sense, this work proposes a model for automatic classification of urban soundscapes. This model is intended for the automatic classification of urban soundscapes based on underlying acoustical and perceptual criteria. Thus, this classification model is proposed to be used as a tool for a comprehensive urban soundscape evaluation. Because of the great complexity associated with the problem, two machine learning techniques, Support Vector Machines (SVM) and Support Vector Machines trained with Sequential Minimal Optimization (SMO), are implemented in developing model classification. The results indicate that the SMO model outperforms the SVM model in the specific task of soundscape classification. With the implementation of the SMO algorithm, the classification model achieves an outstanding performance (91.3% of instances correctly classified). © 2013 Elsevier B.V. All rights reserved.

Automated classification of dolphin echolocation click types from the Gulf of Mexico

PubMed Central

Roch, Marie A.; Soldevilla, Melissa S.; Wiggins, Sean M.; Garrison, Lance P.; Hildebrand, John A.

2017-01-01

Delphinids produce large numbers of short duration, broadband echolocation clicks which may be useful for species classification in passive acoustic monitoring efforts. A challenge in echolocation click classification is to overcome the many sources of variability to recognize underlying patterns across many detections. An automated unsupervised network-based classification method was developed to simulate the approach a human analyst uses when categorizing click types: Clusters of similar clicks were identified by incorporating multiple click characteristics (spectral shape and inter-click interval distributions) to distinguish within-type from between-type variation, and identify distinct, persistent click types. Once click types were established, an algorithm for classifying novel detections using existing clusters was tested. The automated classification method was applied to a dataset of 52 million clicks detected across five monitoring sites over two years in the Gulf of Mexico (GOM). Seven distinct click types were identified, one of which is known to be associated with an acoustically identifiable delphinid (Risso’s dolphin) and six of which are not yet identified. All types occurred at multiple monitoring locations, but the relative occurrence of types varied, particularly between continental shelf and slope locations. Automatically-identified click types from autonomous seafloor recorders without verifiable species identification were compared with clicks detected on sea-surface towed hydrophone arrays in the presence of visually identified delphinid species. These comparisons suggest potential species identities for the animals producing some echolocation click types. The network-based classification method presented here is effective for rapid, unsupervised delphinid click classification across large datasets in which the click types may not be known a priori. PMID:29216184

Audio Tracking in Noisy Environments by Acoustic Map and Spectral Signature.

PubMed

Crocco, Marco; Martelli, Samuele; Trucco, Andrea; Zunino, Andrea; Murino, Vittorio

2018-05-01

A novel method is proposed for generic target tracking by audio measurements from a microphone array. To cope with noisy environments characterized by persistent and high energy interfering sources, a classification map (CM) based on spectral signatures is calculated by means of a machine learning algorithm. Next, the CM is combined with the acoustic map, describing the spatial distribution of sound energy, in order to obtain a cleaned joint map in which contributions from the disturbing sources are removed. A likelihood function is derived from this map and fed to a particle filter yielding the target location estimation on the acoustic image. The method is tested on two real environments, addressing both speaker and vehicle tracking. The comparison with a couple of trackers, relying on the acoustic map only, shows a sharp improvement in performance, paving the way to the application of audio tracking in real challenging environments.

Aircraft Operations Classification System

NASA Technical Reports Server (NTRS)

Harlow, Charles; Zhu, Weihong

2001-01-01

Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.

Bird sound spectrogram decomposition through Non-Negative Matrix Factorization for the acoustic classification of bird species.

PubMed

Ludeña-Choez, Jimmy; Quispe-Soncco, Raisa; Gallardo-Antolín, Ascensión

2017-01-01

Feature extraction for Acoustic Bird Species Classification (ABSC) tasks has traditionally been based on parametric representations that were specifically developed for speech signals, such as Mel Frequency Cepstral Coefficients (MFCC). However, the discrimination capabilities of these features for ABSC could be enhanced by accounting for the vocal production mechanisms of birds, and, in particular, the spectro-temporal structure of bird sounds. In this paper, a new front-end for ABSC is proposed that incorporates this specific information through the non-negative decomposition of bird sound spectrograms. It consists of the following two different stages: short-time feature extraction and temporal feature integration. In the first stage, which aims at providing a better spectral representation of bird sounds on a frame-by-frame basis, two methods are evaluated. In the first method, cepstral-like features (NMF_CC) are extracted by using a filter bank that is automatically learned by means of the application of Non-Negative Matrix Factorization (NMF) on bird audio spectrograms. In the second method, the features are directly derived from the activation coefficients of the spectrogram decomposition as performed through NMF (H_CC). The second stage summarizes the most relevant information contained in the short-time features by computing several statistical measures over long segments. The experiments show that the use of NMF_CC and H_CC in conjunction with temporal integration significantly improves the performance of a Support Vector Machine (SVM)-based ABSC system with respect to conventional MFCC.

Bird sound spectrogram decomposition through Non-Negative Matrix Factorization for the acoustic classification of bird species

PubMed Central

Quispe-Soncco, Raisa

2017-01-01

Feature extraction for Acoustic Bird Species Classification (ABSC) tasks has traditionally been based on parametric representations that were specifically developed for speech signals, such as Mel Frequency Cepstral Coefficients (MFCC). However, the discrimination capabilities of these features for ABSC could be enhanced by accounting for the vocal production mechanisms of birds, and, in particular, the spectro-temporal structure of bird sounds. In this paper, a new front-end for ABSC is proposed that incorporates this specific information through the non-negative decomposition of bird sound spectrograms. It consists of the following two different stages: short-time feature extraction and temporal feature integration. In the first stage, which aims at providing a better spectral representation of bird sounds on a frame-by-frame basis, two methods are evaluated. In the first method, cepstral-like features (NMF_CC) are extracted by using a filter bank that is automatically learned by means of the application of Non-Negative Matrix Factorization (NMF) on bird audio spectrograms. In the second method, the features are directly derived from the activation coefficients of the spectrogram decomposition as performed through NMF (H_CC). The second stage summarizes the most relevant information contained in the short-time features by computing several statistical measures over long segments. The experiments show that the use of NMF_CC and H_CC in conjunction with temporal integration significantly improves the performance of a Support Vector Machine (SVM)-based ABSC system with respect to conventional MFCC. PMID:28628630

Relative acoustic frequency response of induced methane, carbon dioxide and air gas bubble plumes, observed laterally.

PubMed

Kubilius, Rokas; Pedersen, Geir

2016-10-01

There is an increased need to detect, identify, and monitor natural and manmade seabed gas leaks. Fisheries echosounders are well suited to monitor large volumes of water and acoustic frequency response [normalized acoustic backscatter, when a measure at one selected frequency is used as a denominator, r(f)] is commonly used to identify echoes from fish and zooplankton species. Information on gas plume r(f) would be valuable for automatic detection of subsea leaks and for separating bubble plumes from natural targets such as swimbladder-bearing fish. Controlled leaks were produced with a specially designed instrument frame suspended in mid-water in a sheltered fjord. The frame was equipped with echosounders, stereo-camera, and gas-release nozzles. The r(f) of laterally observed methane, carbon dioxide, and air plumes (0.040-29 l/min) were measured at 70, 120, 200, and 333 kHz, with bubble sizes determined optically. The observed bubble size range (1-25 mm) was comparable to that reported in the literature for natural cold seeps of methane. A negative r(f) with increasing frequency was observed, namely, r(f) of about 0.7, 0.6, and 0.5 at 120, 200, and 333 kHz when normalized to 70 kHz. Measured plume r(f) is also compared to resolved, single bubble target strength-based, and modeled r(f).

Underwater target classification using wavelet packets and neural networks.

PubMed

Azimi-Sadjadi, M R; Yao, D; Huang, Q; Dobeck, G J

2000-01-01

In this paper, a new subband-based classification scheme is developed for classifying underwater mines and mine-like targets from the acoustic backscattered signals. The system consists of a feature extractor using wavelet packets in conjunction with linear predictive coding (LPC), a feature selection scheme, and a backpropagation neural-network classifier. The data set used for this study consists of the backscattered signals from six different objects: two mine-like targets and four nontargets for several aspect angles. Simulation results on ten different noisy realizations and for signal-to-noise ratio (SNR) of 12 dB are presented. The receiver operating characteristic (ROC) curve of the classifier generated based on these results demonstrated excellent classification performance of the system. The generalization ability of the trained network was demonstrated by computing the error and classification rate statistics on a large data set. A multiaspect fusion scheme was also adopted in order to further improve the classification performance.

Spatial and temporal variation of acoustic backscatter in the STRESS experiment

NASA Astrophysics Data System (ADS)

Dworski, J. George; Jackson, Darrell R.

1994-08-01

Acoustic backscatter measurements were made of the seabed with a bottom mounted, circularly scanning sonar. The placement was at 91 m depth, mid-shelf of Northern California (38° 34'N), site C3 of the experiment STRESS I (1988-1989). Our expectation was that sonar images (70 m radius, 12,000 m 2) would provide a means of observing, over a large field of view, changes in the bottom due to storm-induced sediment transport and due to bioturbation. This expectation was supported in part by towed sonar measurements at 35 kHz over a sandy area in the North Sea, where dramatic spatial variation in the level of the backseattered signal was observed during an Autumn storm on scales of a few km with no concomitant change in sediment grain size [ JACKSONet al. (1986) The Journal of the Acoustical Society of America, 80, 1188-1199]. It appeared possible that storm-driven sediment transport might have been responsible for this patchiness, by altering bottom roughness and by redeposition of suspended material. At the California site, a conventional sonar processing of our data from the STRESS experiment reveals no such dramatic change in backscattered signal level due to storms. The sonar images contain random structures whose time evolution is subtle and difficult to interpret. A much clearer picture of temporal and spatial variations emerges from a processing scheme involving cross-correlation of time-separated acoustic views of the bottom. In effect, the sequence of correlation data images produces a movie in which patches of activity are seen to develop as functions of time. It appears that most of this activity is biological rather than hydrodynamic. A tentative explanation is two-fold. The bottom shear stress might have been considerably greater at the North Sea site (with depth only one-half of the California site). The seafloor at the California site was silty-clayey, and backscatter from such floor is less sensitive to the water-floor interface shape and roughness than

Leak detection in gas pipeline by acoustic and signal processing - A review

NASA Astrophysics Data System (ADS)

Adnan, N. F.; Ghazali, M. F.; Amin, M. M.; Hamat, A. M. A.

2015-12-01

The pipeline system is the most important part in media transport in order to deliver fluid to another station. The weak maintenance and poor safety will contribute to financial losses in term of fluid waste and environmental impacts. There are many classifications of techniques to make it easier to show their specific method and application. This paper's discussion about gas leak detection in pipeline system using acoustic method will be presented in this paper. The wave propagation in the pipeline is a key parameter in acoustic method when the leak occurs and the pressure balance of the pipe will generated by the friction between wall in the pipe. The signal processing is used to decompose the raw signal and show in time- frequency. Findings based on the acoustic method can be used for comparative study in the future. Acoustic signal and HHT is the best method to detect leak in gas pipelines. More experiments and simulation need to be carried out to get the fast result of leaking and estimation of their location.

Characterization of Sedimentary Deposits Using usSEABED for Large-scale Mapping, Modeling and Research of U.S.Continental Margins

NASA Astrophysics Data System (ADS)

Williams, S. J.; Reid, J. A.; Arsenault, M. A.; Jenkins, C.

2006-12-01

Geologic maps of offshore areas containing detailed morphologic features and sediment character can serve many scientific and operational purposes. Such maps have been lacking, but recent computer technology and software to capture diverse marine data are offering promise. Continental margins, products of complex geologic history and dynamic oceanographic processes, dominated by the Holocene marine transgression, contain landforms which provide a variety of important functions: critical habitats for fish, ship navigation, national defense, and engineering activities (i.e., oil and gas platforms, pipeline and cable routes, wind-energy sites) and contain important sedimentary records. Some shelf areas also contain sedimentary deposits such as sand and gravel, regarded as potential aggregate resources for mitigating coastal erosion, reducing vulnerability to hazards, and restoring ecosystems. Because coastal and offshore areas are increasingly important, knowledge of the framework geology and marine processes is useful to many. Especially valuable are comprehensive and integrated digital databases based on data from original sources in the marine community. Products of interest are GIS maps containing thematic information such as seafloor physiography, geology, sediment character and texture, seafloor roughness, and geotechnical engineering properties. These map products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The USGS with partners is leading a Nation-wide program to gather a wide variety of extant marine geologic data into the usSEABED system (http://walrus.wr.usgs/usseabed). This provides a centralized, fully integrated digital database of marine geologic data collected over the past 50 years by USGS, other federal and state agencies, universities and private companies. To date, approximately 325,000 data points from the U.S. EEZ reside in usSEABED. The usSEABED, which combines a broad array of physical data

INFOMAR - Ireland's National Seabed Mapping Programme: A Tool For Marine Spatial Planning

NASA Astrophysics Data System (ADS)

Furey, T. M.

2016-02-01

INFOMAR is Ireland's national seabed mapping programme and is a key action in the national integrated marine plan, Harnessing Our Ocean Wealth. It comprises a multi-platform approach to delivering marine integrated mapping in 2 phases, over a projected 20 year timeline (2006-2026). The programme has three work strands; Data Acquisition, Data Exchange and Integration, and Value Added Exploitation. The Data Acquisition strand includes collection of hydrographic, oceanographic, geological, habitat and heritage datasets that will underpin future sustainable development and management of Ireland's marine resource. INFOMAR outputs are delivered through the Data Exchange and Integration strand. Uses of these outputs are wide ranging and multipurpose, from management plans for fisheries, aquaculture and coastal protection works, to environmental impact assessments, ocean renewable development and integrated coastal zone management. In order to address the evolution and diversification of maritime user requirements, the programme has realigned and developed outputs and new products, in part, through an innovative research funding initiative. Development is also fostered through the Value Added Exploitation strand. INFOMAR outputs and products serve to underpin delivery of Ireland's statutory obligations and enhance compliance with EU and national legislation. This is achieved through co-operation with the agencies responsible for supporting Ireland's international obligations and for the implementation of marine spatial planning. A strategic national seabed mapping programme such as INFOMAR, provides a critical baseline dataset which underpins development of the marine economy, and improves our understanding of the response of marine systems to pressures, and the effect of cumulative impacts. This paper will focus on the evolution and scope of INFOMAR, and look at examples of outputs being harnessed to serve approaches to the management of activities having an impact on the

Method of Adjusting Acoustic Impedances for Impedance-Tunable Acoustic Segments

NASA Technical Reports Server (NTRS)

Jones, Kennie H (Inventor); Nark, Douglas M. (Inventor); Jones, Michael G. (Inventor); Parrott, Tony L. (Inventor); Lodding, Kenneth N. (Inventor)

2012-01-01

A method is provided for making localized decisions and taking localized actions to achieve a global solution. In an embodiment of the present invention, acoustic impedances for impedance-tunable acoustic segments are adjusted. A first acoustic segment through an N-th acoustic segment are defined. To start the process, the first acoustic segment is designated as a leader and a noise-reducing impedance is determined therefor. This is accomplished using (i) one or more metrics associated with the acoustic wave at the leader, and (ii) the metric(s) associated with the acoustic wave at the N-th acoustic segment. The leader, the N-th acoustic segment, and each of the acoustic segments exclusive of the leader and the N-th acoustic segment, are tuned to the noise-reducing impedance. The current leader is then excluded from subsequent processing steps. The designation of leader is then given one of the remaining acoustic segments, and the process is repeated for each of the acoustic segments through an (N-1)-th one of the acoustic segments.

Perceptual integration of acoustic cues to laryngeal contrasts in Korean fricatives.

PubMed

Lee, Sarah; Katz, Jonah

2016-02-01

This paper provides evidence that multiple acoustic cues involving the presence of low-frequency energy integrate in the perception of Korean coronal fricatives. This finding helps explain a surprising asymmetry between the production and perception of these fricatives found in previous studies: lower F0 onset in the following vowel leads to a response bias for plain [s] over fortis [s*], despite the fact that there is no evidence for a corresponding acoustic asymmetry in the production of [s] and [s*]. A fixed classification task using the Garner paradigm provides evidence that low F0 in a following vowel and the presence of voicing during frication perceptually integrate. This suggests that Korean listeners in previous experiments were responding to an "intermediate perceptual property" of stimuli, despite the fact that the individual acoustic components of that property are not all present in typical Korean fricative productions. The finding also broadens empirical support for the general idea of perceptual integration to a language, a different manner of consonant, and a situation where covariance of the acoustic cues under investigation is not generally present in a listener's linguistic input.

Acoustic detection of biosonar activity of deep diving odontocetes at Josephine Seamount High Seas Marine Protected Area.

PubMed

Giorli, Giacomo; Au, Whitlow W L; Ou, Hui; Jarvis, Susan; Morrissey, Ronald; Moretti, David

2015-05-01

The temporal occurrence of deep diving cetaceans in the Josephine Seamount High Seas Marine Protected Area (JSHSMPA), south-west Portugal, was monitored using a passive acoustic recorder. The recorder was deployed on 13 May 2010 at a depth of 814 m during the North Atlantic Treaty Organization Centre for Maritime Research and Experimentation cruise "Sirena10" and recovered on 6 June 2010. The recorder was programmed to record 40 s of data every 2 min. Acoustic data analysis, for the detection and classification of echolocation clicks, was performed using automatic detector/classification systems: M3R (Marine Mammal Monitoring on Navy Ranges), a custom matlab program, and an operator-supervised custom matlab program to assess the classification performance of the detector/classification systems. M3R CS-SVM algorithm contains templates to detect beaked whales, sperm whales, blackfish (pilot and false killer whales), and Risso's dolphins. The detections of each group of odontocetes was monitored as a function of time. Blackfish and Risso's dolphins were detected every day, while beaked whales and sperm whales were detected almost every day. The hourly distribution of detections reveals that blackfish and Risso's dolphins were more active at night, while beaked whales and sperm whales were more active during daylight hours.

Translational illusion of acoustic sources by transformation acoustics.

PubMed

Sun, Fei; Li, Shichao; He, Sailing

2017-09-01

An acoustic illusion of creating a translated acoustic source is designed by utilizing transformation acoustics. An acoustic source shifter (ASS) composed of layered acoustic metamaterials is designed to achieve such an illusion. A practical example where the ASS is made with naturally available materials is also given. Numerical simulations verify the performance of the proposed device. The designed ASS may have some applications in, e.g., anti-sonar detection.

Underwater object classification using scattering transform of sonar signals

NASA Astrophysics Data System (ADS)

Saito, Naoki; Weber, David S.

2017-08-01

In this paper, we apply the scattering transform (ST)-a nonlinear map based off of a convolutional neural network (CNN)-to classification of underwater objects using sonar signals. The ST formalizes the observation that the filters learned by a CNN have wavelet-like structure. We achieve effective binary classification both on a real dataset of Unexploded Ordinance (UXOs), as well as synthetically generated examples. We also explore the effects on the waveforms with respect to changes in the object domain (e.g., translation, rotation, and acoustic impedance, etc.), and examine the consequences coming from theoretical results for the scattering transform. We show that the scattering transform is capable of excellent classification on both the synthetic and real problems, thanks to having more quasi-invariance properties that are well-suited to translation and rotation of the object.

An approach for automatic classification of grouper vocalizations with passive acoustic monitoring.

PubMed

Ibrahim, Ali K; Chérubin, Laurent M; Zhuang, Hanqi; Schärer Umpierre, Michelle T; Dalgleish, Fraser; Erdol, Nurgun; Ouyang, B; Dalgleish, A

2018-02-01

Grouper, a family of marine fishes, produce distinct vocalizations associated with their reproductive behavior during spawning aggregation. These low frequencies sounds (50-350 Hz) consist of a series of pulses repeated at a variable rate. In this paper, an approach is presented for automatic classification of grouper vocalizations from ambient sounds recorded in situ with fixed hydrophones based on weighted features and sparse classifier. Group sounds were labeled initially by humans for training and testing various feature extraction and classification methods. In the feature extraction phase, four types of features were used to extract features of sounds produced by groupers. Once the sound features were extracted, three types of representative classifiers were applied to categorize the species that produced these sounds. Experimental results showed that the overall percentage of identification using the best combination of the selected feature extractor weighted mel frequency cepstral coefficients and sparse classifier achieved 82.7% accuracy. The proposed algorithm has been implemented in an autonomous platform (wave glider) for real-time detection and classification of group vocalizations.

Using novel acoustic and visual mapping tools to predict the small-scale spatial distribution of live biogenic reef framework in cold-water coral habitats

NASA Astrophysics Data System (ADS)

De Clippele, L. H.; Gafeira, J.; Robert, K.; Hennige, S.; Lavaleye, M. S.; Duineveld, G. C. A.; Huvenne, V. A. I.; Roberts, J. M.

2017-03-01

Cold-water corals form substantial biogenic habitats on continental shelves and in deep-sea areas with topographic highs, such as banks and seamounts. In the Atlantic, many reef and mound complexes are engineered by Lophelia pertusa, the dominant framework-forming coral. In this study, a variety of mapping approaches were used at a range of scales to map the distribution of both cold-water coral habitats and individual coral colonies at the Mingulay Reef Complex (west Scotland). The new ArcGIS-based British Geological Survey (BGS) seabed mapping toolbox semi-automatically delineated over 500 Lophelia reef `mini-mounds' from bathymetry data with 2-m resolution. The morphometric and acoustic characteristics of the mini-mounds were also automatically quantified and captured using this toolbox. Coral presence data were derived from high-definition remotely operated vehicle (ROV) records and high-resolution microbathymetry collected by a ROV-mounted multibeam echosounder. With a resolution of 0.35 × 0.35 m, the microbathymetry covers 0.6 km2 in the centre of the study area and allowed identification of individual live coral colonies in acoustic data for the first time. Maximum water depth, maximum rugosity, mean rugosity, bathymetric positioning index and maximum current speed were identified as the environmental variables that contributed most to the prediction of live coral presence. These variables were used to create a predictive map of the likelihood of presence of live cold-water coral colonies in the area of the Mingulay Reef Complex covered by the 2-m resolution data set. Predictive maps of live corals across the reef will be especially valuable for future long-term monitoring surveys, including those needed to understand the impacts of global climate change. This is the first study using the newly developed BGS seabed mapping toolbox and an ROV-based microbathymetric grid to explore the environmental variables that control coral growth on cold-water coral

Three-dimensional parabolic equation models of the acoustic coverage of the CTBT hydrophone station at Crozet

NASA Astrophysics Data System (ADS)

Zampolli, Mario; Haralabus, Georgios; Prior, Mark K.; Heaney, Kevin D.; Campbell, Richard

2014-05-01

Hydrophone stations of the Comprehensive Nuclear-Test-Ban Organisation (CTBTO) International Monitoring System (IMS), with the exception of one in Australia, comprise two triplets of submerged moored hydrophones, one North and one South of the island from which the respective system is deployed. Triplet distances vary approximately between 50 - 100 km from the island, with each triplet connected to the receiving shore equipment by fibre-optic submarine data cables. Once deployed, the systems relay underwater acoustic waveforms in the band 1 - 100 Hz in real time to Vienna via a shore based satellite link. The design life of hydroacoustic stations is at least 20 years, without need for any maintenance of the underwater system. The re-establishment of hydrophone monitoring station HA04 at Crozet (French Southern and Antarctic Territories) in the South-Western Indian Ocean is currently being investigated. In order to determine appropriate locations and depths for the installation of the hydrophones a number of constraints need to be taken into account and balanced against each other. The most important of these are (i) hydrophone depth in a region where the sound-speed profile is mostly upward refracting and the Sound Fixing and Ranging (SOFAR) channel is not well defined, (ii) a safe distance from the surface currents which occupy the first few hundred meters of the water column, (iii) seabed slopes that enable the safe deployment of the hydrophone mooring bases, (iv) avoidance of regions of high internal tide activity, (v) choice of locations to optimize basin and cross-basin scale acoustic coverage of each triplet and (vi) redundancy considerations so that one triplet can partially cover for the other one in case of necessity. A state-of-the-art three-dimensional (3-D) parabolic equation acoustic propagation model was used to model the propagation for a number of potential triplet locations. Criteria for short-listing candidate triplet locations were based on

Distributed acoustic cues for caller identity in macaque vocalization.

PubMed

Fukushima, Makoto; Doyle, Alex M; Mullarkey, Matthew P; Mishkin, Mortimer; Averbeck, Bruno B

2015-12-01

Individual primates can be identified by the sound of their voice. Macaques have demonstrated an ability to discern conspecific identity from a harmonically structured 'coo' call. Voice recognition presumably requires the integrated perception of multiple acoustic features. However, it is unclear how this is achieved, given considerable variability across utterances. Specifically, the extent to which information about caller identity is distributed across multiple features remains elusive. We examined these issues by recording and analysing a large sample of calls from eight macaques. Single acoustic features, including fundamental frequency, duration and Weiner entropy, were informative but unreliable for the statistical classification of caller identity. A combination of multiple features, however, allowed for highly accurate caller identification. A regularized classifier that learned to identify callers from the modulation power spectrum of calls found that specific regions of spectral-temporal modulation were informative for caller identification. These ranges are related to acoustic features such as the call's fundamental frequency and FM sweep direction. We further found that the low-frequency spectrotemporal modulation component contained an indexical cue of the caller body size. Thus, cues for caller identity are distributed across identifiable spectrotemporal components corresponding to laryngeal and supralaryngeal components of vocalizations, and the integration of those cues can enable highly reliable caller identification. Our results demonstrate a clear acoustic basis by which individual macaque vocalizations can be recognized.

Distributed acoustic cues for caller identity in macaque vocalization

PubMed Central

Doyle, Alex M.; Mullarkey, Matthew P.; Mishkin, Mortimer; Averbeck, Bruno B.

2015-01-01

Individual primates can be identified by the sound of their voice. Macaques have demonstrated an ability to discern conspecific identity from a harmonically structured ‘coo’ call. Voice recognition presumably requires the integrated perception of multiple acoustic features. However, it is unclear how this is achieved, given considerable variability across utterances. Specifically, the extent to which information about caller identity is distributed across multiple features remains elusive. We examined these issues by recording and analysing a large sample of calls from eight macaques. Single acoustic features, including fundamental frequency, duration and Weiner entropy, were informative but unreliable for the statistical classification of caller identity. A combination of multiple features, however, allowed for highly accurate caller identification. A regularized classifier that learned to identify callers from the modulation power spectrum of calls found that specific regions of spectral–temporal modulation were informative for caller identification. These ranges are related to acoustic features such as the call’s fundamental frequency and FM sweep direction. We further found that the low-frequency spectrotemporal modulation component contained an indexical cue of the caller body size. Thus, cues for caller identity are distributed across identifiable spectrotemporal components corresponding to laryngeal and supralaryngeal components of vocalizations, and the integration of those cues can enable highly reliable caller identification. Our results demonstrate a clear acoustic basis by which individual macaque vocalizations can be recognized. PMID:27019727

Acoustic Tonal and Vector Properties of Red Hind Grouper Vocalizations

NASA Astrophysics Data System (ADS)

Matthews, Cameron Anthony

Vertebrates are the most prodigious vocalizing animals in existence, and the most diverse methods of acoustic communication among vertebrates can be found in the ocean. Relatively many teleost fish are gifted with the ability to communicate acoustically, and the family of serranidae often performs this as a function of the swim bladder. Epinephelus Guttatus (E. guttatus), or more commonly the red hind grouper, is equipped with a drum shaped swim bladder acting as a monopole under typical ocean conditions. This configuration allows for what is understood to be omnidirectional projection of tones approximately centered between 40 and 440 Hz and spanning anywhere from 40 to 200 Hz of bandwidth and modulation effects based on observed data provided by researchers. Prior studies on many other fish show correlation in acoustic communication profile with length, size and sexual identity. In the red hind, sexual dimorphism leads to an inherent female identity in all juvenile fish which converts to male according to environmental factors, recommending at least consistent organs across both sexes be assumed even if not in use. Much research has been performed on male fish vocalization in terms of spectral content. Communication in fish is a complex multi-modal process, with acoustic communication being important for many of the species, particularly those in the littoral regions of the worlds' oceans. If identifying characteristics of the red hind vocalization can be isolated based on detection, classification, tracking and localizing methodologies, then these identifying characteristics may indeed lead to passive feature identification that allows for estimation of individual fish mass. Hypotheses based on vector, cyclostationary and classical tonal mechanics are presented for consideration. A battery of test data collection events, applying pre-recorded fish vocalizations to a geolocated undersea sound source were conducted. The results are supplied with the intent of

Vibratory regime classification of infant phonation.

PubMed

Buder, Eugene H; Chorna, Lesya B; Oller, D Kimbrough; Robinson, Rebecca B

2008-09-01

Infant phonation is highly variable in many respects, including the basic vibratory patterns by which the vocal tissues create acoustic signals. Previous studies have identified the regular occurrence of nonmodal phonation types in normal infant phonation. The glottis is like many oscillating systems that, because of nonlinear relationships among the elements, may vibrate in ways representing the deterministic patterns classified theoretically within the mathematical framework of nonlinear dynamics. The infant's preverbal vocal explorations present such a variety of phonations that it may be possible to find effectively all the classes of vibration predicted by nonlinear dynamic theory. The current report defines acoustic criteria for an important subset of such vibratory regimes, and demonstrates that analysts can be trained to reliably use these criteria for a classification that includes all instances of infant phonation in the recorded corpora. The method is thus internally comprehensive in the sense that all phonations are classified, but it is not exhaustive in the sense that all vocal qualities are thereby represented. Using the methods thus developed, this study also demonstrates that the distributions of these phonation types vary significantly across sessions of recording in the first year of life, suggesting developmental changes. The method of regime classification is thus capable of tracking changes that may be indicative of maturation of the mechanism, the learning of categories of phonatory control, and the possibly varying use of vocalizations across social contexts.

Vibratory Regime Classification of Infant Phonation

PubMed Central

Buder, Eugene H.; Chorna, Lesya B.; Oller, D. Kimbrough; Robinson, Rebecca B.

2008-01-01

Infant phonation is highly variable in many respects, including the basic vibratory patterns by which the vocal tissues create acoustic signals. Previous studies have identified the regular occurrence of non-modal phonation types in normal infant phonation. The glottis is like many oscillating systems that, because of non-linear relationships among the elements, may vibrate in ways representing the deterministic patterns classified theoretically within the mathematical framework of non-linear dynamics. The infant’s pre-verbal vocal explorations present such a variety of phonations that it may be possible to find effectively all the classes of vibration predicted by non-linear dynamic theory. The current report defines acoustic criteria for an important subset of such vibratory regimes, and demonstrates that analysts can be trained to reliably use these criteria for a classification that includes all instances of infant phonation in the recorded corpora. The method is thus internally comprehensive in the sense that all phonations are classified, but it is not exhaustive in the sense that all vocal qualities are thereby represented. Using the methods thus developed, this study also demonstrates that the distributions of these phonation types vary significantly across sessions of recording in the first year of life, suggesting developmental changes. The method of regime classification is thus capable of tracking changes that may be indicative of maturation of the mechanism, the learning of categories of phonatory control, and the possibly varying use of vocalizations across social contexts. PMID:17509829

Predicting couple therapy outcomes based on speech acoustic features

PubMed Central

Nasir, Md; Baucom, Brian Robert; Narayanan, Shrikanth

2017-01-01

Automated assessment and prediction of marital outcome in couples therapy is a challenging task but promises to be a potentially useful tool for clinical psychologists. Computational approaches for inferring therapy outcomes using observable behavioral information obtained from conversations between spouses offer objective means for understanding relationship dynamics. In this work, we explore whether the acoustics of the spoken interactions of clinically distressed spouses provide information towards assessment of therapy outcomes. The therapy outcome prediction task in this work includes detecting whether there was a relationship improvement or not (posed as a binary classification) as well as discerning varying levels of improvement or decline in the relationship status (posed as a multiclass recognition task). We use each interlocutor’s acoustic speech signal characteristics such as vocal intonation and intensity, both independently and in relation to one another, as cues for predicting the therapy outcome. We also compare prediction performance with one obtained via standardized behavioral codes characterizing the relationship dynamics provided by human experts as features for automated classification. Our experiments, using data from a longitudinal clinical study of couples in distressed relations, showed that predictions of relationship outcomes obtained directly from vocal acoustics are comparable or superior to those obtained using human-rated behavioral codes as prediction features. In addition, combining direct signal-derived features with manually coded behavioral features improved the prediction performance in most cases, indicating the complementarity of relevant information captured by humans and machine algorithms. Additionally, considering the vocal properties of the interlocutors in relation to one another, rather than in isolation, showed to be important for improving the automatic prediction. This finding supports the notion that behavioral

Heard Island and McDonald Islands Acoustic Plumes: Split-beam Echo sounder and Deep Tow Camera Observations of Gas Seeps on the Central Kerguelen Plateau

NASA Astrophysics Data System (ADS)

Watson, S. J.; Spain, E. A.; Coffin, M. F.; Whittaker, J. M.; Fox, J. M.; Bowie, A. R.

2016-12-01

Heard and McDonald islands (HIMI) are two active volcanic edifices on the Central Kerguelen Plateau. Scientists aboard the Heard Earth-Ocean-Biosphere Interactions voyage in early 2016 explored how this volcanic activity manifests itself near HIMI. Using Simrad EK60 split-beam echo sounder and deep tow camera data from RV Investigator, we recorded the distribution of seafloor emissions, providing the first direct evidence of seabed discharge around HIMI, mapping >244 acoustic plume signals. Northeast of Heard, three distinct plume clusters are associated with bubbles (towed camera) and the largest directly overlies a sub-seafloor opaque zone (sub-bottom profiler) with >140 zones observed within 6.5 km. Large temperature anomalies did not characterize any of the acoustic plumes where temperature data were recorded. We therefore suggest that these plumes are cold methane seeps. Acoustic properties - mean volume backscattering and target strength - and morphology - height, width, depth to surface - of plumes around McDonald resembled those northeast of Heard, also suggesting gas bubbles. We observed no bubbles on extremely limited towed camera data around McDonald; however, visibility was poor. The acoustic response of the plumes at different frequencies (120 kHz vs. 18 kHz), a technique used to classify water column scatterers, differed between HIMI, suggestiing dissimilar target size (bubble radii) distributions. Environmental context and temporal characteristics of the plumes differed between HIMI. Heard plumes were concentrated on flat, sediment rich plains, whereas around McDonald plumes emanated from sea knolls and mounds with hard volcanic seafloor. The Heard plumes were consistent temporally, while the McDonald plumes varied temporally possibly related to tides or subsurface processes. Our data and analyses suggest that HIMI acoustic plumes were likely caused by gas bubbles; however, the bubbles may originate from two or more distinct processes.

Acoustic, genetic and morphological variations within the katydid Gampsocleis sedakovii (Orthoptera, Tettigonioidea)

PubMed Central

Zhang, Xue; Wen, Ming; Li, Junjian; Zhu, Hui; Wang, Yinliang; Ren, Bingzhong

2015-01-01

Abstract In an attempt to explain the variation within this species and clarify the subspecies classification, an analysis of the genetic, calling songs, and morphological variations within the species Gampsocleis sedakovii is presented from Inner Mongolia, China. Recordings were compared of the male calling songs and analysis performed of selected acoustic variables. This analysis is combined with sequencing of mtDNA - COI and examination of morphological traits to perform cluster analyses. The trees constructed from different datasets were structurally similar, bisecting the six geographical populations studied. Based on two large branches in the analysis, the species Gampsocleis sedakovii was partitioned into two subspecies, Gampsocleis sedakovii sedakovii (Fischer von Waldheim, 1846) and Gampsocleis sedakovii obscura (Walker, 1869). Comparing all the traits, the individual of Elunchun (ELC) was the intermediate type in this species according to the acoustic, genetic, and morphological characteristics. This study provides evidence for insect acoustic signal divergence and the process of subspeciation. PMID:26692795

Fundamentals of Acoustics. Psychoacoustics and Hearing. Acoustical Measurements

NASA Technical Reports Server (NTRS)

Begault, Durand R.; Ahumada, Al (Technical Monitor)

1997-01-01

These are 3 chapters that will appear in a book titled "Building Acoustical Design", edited by Charles Salter. They are designed to introduce the reader to fundamental concepts of acoustics, particularly as they relate to the built environment. "Fundamentals of Acoustics" reviews basic concepts of sound waveform frequency, pressure, and phase. "Psychoacoustics and Hearing" discusses the human interpretation sound pressure as loudness, particularly as a function of frequency. "Acoustic Measurements" gives a simple overview of the time and frequency weightings for sound pressure measurements that are used in acoustical work.

Acoustic source for generating an acoustic beam

DOEpatents

Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

2016-05-31

An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

1995-01-01

An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors

NASA Technical Reports Server (NTRS)

Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)

1994-01-01

An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.

North Pacific Acoustic Laboratory and Deep Water Acoustics

DTIC Science & Technology

2015-09-30

range acoustic systems, whether for acoustic surveillance, communication, or remote sensing of the ocean interior . The data from the NPAL network, and...1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. North Pacific Acoustic Laboratory and Deep Water... Acoustics PI James A. Mercer Applied Physics Laboratory, University of Washington 1013 NE 40th Street Seattle, WA 98105 phone: (206) 543-1361 fax

Analysis of the acoustic spectral signature of prosthetic heart valves in patients experiencing atrial fibrillation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott, D.D.; Jones, H.E.

1994-05-06

Prosthetic heart valves have increased the life span of many patients with life threatening heart conditions. These valves have proven extremely reliable adding years to what would have been weeks to a patient`s life. Prosthetic valves, like the heart however, can suffer from this constant work load. A small number of valves have experienced structural fractures of the outlet strut due to fatigue. To study this problem a non-intrusive method to classify valves has been developed. By extracting from an acoustic signal the opening sounds which directly contain information from the outlet strut and then developing features which are suppliedmore » to an adaptive classification scheme (neural network) the condition of the valve can be determined. The opening sound extraction process has proved to be a classification problem itself. Due to the uniqueness of each heart and the occasional irregularity of the acoustic pattern it is often questionable as to the integrity of a given signal (beat), especially one occurring during an irregular beat pattern. A common cause of these irregular patterns is a condition known as atrial fibrillation, a prevalent arrhythmia among patients with prosthetic hear valves. Atrial fibrillation is suspected when the ECG shows no obvious P-waves. The atria do not contract and relax correctly to help contribute to ventricular filling during a normal cardiac cycle. Sometimes this leads to irregular patterns in the acoustic data. This study compares normal beat patterns to irregular patterns of the same heart. By analyzing the spectral content of the beats it can be determined whether or not these irregular patterns can contribute to the classification of a heart valve or if they should be avoided. The results have shown that the opening sounds which occur during irregular beat patterns contain the same spectral information as the opening which occur during a normal beat pattern of the same heart and these beats can be used for classification.« less

Deep-sea seabed habitats: Do they support distinct mega-epifaunal communities that have different vulnerabilities to anthropogenic disturbance?

NASA Astrophysics Data System (ADS)

Bowden, David A.; Rowden, Ashley A.; Leduc, Daniel; Beaumont, Jennifer; Clark, Malcolm R.

2016-01-01

Growing economic interest in seabed resources in the deep-sea highlights the need for information about the spatial distribution and vulnerability to disturbance of benthic habitats and fauna. Categorisation of seabed habitats for management is often based on topographic features such as canyons and seamounts that can be distinguished using regional bathymetry ('mega-habitats'). This is practical but because such habitats are contiguous with others, there is potential for overlap in the communities associated with them. Because concepts of habitat and community vulnerability are based on the traits of individual taxa, the nature and extent of differences between communities have implications for strategies to manage the environmental effects of resource use. Using towed video camera transects, we surveyed mega-epifaunal communities of three topographically-defined habitats (canyon, seamount or knoll, and continental slope) and two physico-chemically defined meso-scale habitats (cold seep and hydrothermal vent) in two regions off New Zealand to assess whether each supports a distinct type of community. Cold seep and hydrothermal vent communities were strongly distinct from those in other habitats. Across the other habitats, however, distinctions between communities were often weak and were not consistent between regions. Dissimilarities among communities across all habitats were stronger and the density of filter-feeding taxa was higher in the Bay of Plenty than on the Hikurangi Margin, whereas densities of predatory and scavenging taxa were higher on the Hikurangi Margin. Substratum diversity at small spatial scales (<1 km) and trawl history were significantly correlated with community composition in both regions. We conclude that, (1) a lack of consistent distinction between communities raises questions about the general utility of topographically-defined mega-habitats in environmental management, (2) fine-scale survey of individual features is necessary to

Artillery/mortar round type classification to increase system situational awareness

NASA Astrophysics Data System (ADS)

Desai, Sachi; Grasing, David; Morcos, Amir; Hohil, Myron

2008-04-01

Feature extraction methods based on the statistical analysis of the change in event pressure levels over a period and the level of ambient pressure excitation facilitate the development of a robust classification algorithm. The features reliably discriminates mortar and artillery variants via acoustic signals produced during the launch events. Utilizing acoustic sensors to exploit the sound waveform generated from the blast for the identification of mortar and artillery variants as type A, etcetera through analysis of the waveform. Distinct characteristics arise within the different mortar/artillery variants because varying HE mortar payloads and related charges emphasize varying size events at launch. The waveform holds various harmonic properties distinct to a given mortar/artillery variant that through advanced signal processing and data mining techniques can employed to classify a given type. The skewness and other statistical processing techniques are used to extract the predominant components from the acoustic signatures at ranges exceeding 3000m. Exploiting these techniques will help develop a feature set highly independent of range, providing discrimination based on acoustic elements of the blast wave. Highly reliable discrimination will be achieved with a feedforward neural network classifier trained on a feature space derived from the distribution of statistical coefficients, frequency spectrum, and higher frequency details found within different energy bands. The processes that are described herein extend current technologies, which emphasis acoustic sensor systems to provide such situational awareness.

Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

PubMed

Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

2014-11-24

Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

Acoustically Induced Vibration of Structures: Reverberant Vs. Direct Acoustic Testing

NASA Technical Reports Server (NTRS)

Kolaini, Ali R.; O'Connell, Michael R.; Tsoi, Wan B.

2009-01-01

Large reverberant chambers have been used for several decades in the aerospace industry to test larger structures such as solar arrays and reflectors to qualify and to detect faults in the design and fabrication of spacecraft and satellites. In the past decade some companies have begun using direct near field acoustic testing, employing speakers, for qualifying larger structures. A limited test data set obtained from recent acoustic tests of the same hardware exposed to both direct and reverberant acoustic field testing has indicated some differences in the resulting structural responses. In reverberant acoustic testing, higher vibration responses were observed at lower frequencies when compared with the direct acoustic testing. In the case of direct near field acoustic testing higher vibration responses appeared to occur at higher frequencies as well. In reverberant chamber testing and direct acoustic testing, standing acoustic modes of the reverberant chamber or the speakers and spacecraft parallel surfaces can strongly couple with the fundamental structural modes of the test hardware. In this paper data from recent acoustic testing of flight hardware, that yielded evidence of acoustic standing wave coupling with structural responses, are discussed in some detail. Convincing evidence of the acoustic standing wave/structural coupling phenomenon will be discussed, citing observations from acoustic testing of a simple aluminum plate. The implications of such acoustic coupling to testing of sensitive flight hardware will be discussed. The results discussed in this paper reveal issues with over or under testing of flight hardware that could pose unanticipated structural and flight qualification issues. Therefore, it is of paramount importance to understand the structural modal coupling with standing acoustic waves that has been observed in both methods of acoustic testing. This study will assist the community to choose an appropriate testing method and test setup in

A comparative study of the SVM and K-nn machine learning algorithms for the diagnosis of respiratory pathologies using pulmonary acoustic signals.

PubMed

Palaniappan, Rajkumar; Sundaraj, Kenneth; Sundaraj, Sebastian

2014-06-27

Pulmonary acoustic parameters extracted from recorded respiratory sounds provide valuable information for the detection of respiratory pathologies. The automated analysis of pulmonary acoustic signals can serve as a differential diagnosis tool for medical professionals, a learning tool for medical students, and a self-management tool for patients. In this context, we intend to evaluate and compare the performance of the support vector machine (SVM) and K-nearest neighbour (K-nn) classifiers in diagnosis respiratory pathologies using respiratory sounds from R.A.L.E database. The pulmonary acoustic signals used in this study were obtained from the R.A.L.E lung sound database. The pulmonary acoustic signals were manually categorised into three different groups, namely normal, airway obstruction pathology, and parenchymal pathology. The mel-frequency cepstral coefficient (MFCC) features were extracted from the pre-processed pulmonary acoustic signals. The MFCC features were analysed by one-way ANOVA and then fed separately into the SVM and K-nn classifiers. The performances of the classifiers were analysed using the confusion matrix technique. The statistical analysis of the MFCC features using one-way ANOVA showed that the extracted MFCC features are significantly different (p < 0.001). The classification accuracies of the SVM and K-nn classifiers were found to be 92.19% and 98.26%, respectively. Although the data used to train and test the classifiers are limited, the classification accuracies found are satisfactory. The K-nn classifier was better than the SVM classifier for the discrimination of pulmonary acoustic signals from pathological and normal subjects obtained from the RALE database.

A comparative study of the svm and k-nn machine learning algorithms for the diagnosis of respiratory pathologies using pulmonary acoustic signals

PubMed Central

2014-01-01

Background Pulmonary acoustic parameters extracted from recorded respiratory sounds provide valuable information for the detection of respiratory pathologies. The automated analysis of pulmonary acoustic signals can serve as a differential diagnosis tool for medical professionals, a learning tool for medical students, and a self-management tool for patients. In this context, we intend to evaluate and compare the performance of the support vector machine (SVM) and K-nearest neighbour (K-nn) classifiers in diagnosis respiratory pathologies using respiratory sounds from R.A.L.E database. Results The pulmonary acoustic signals used in this study were obtained from the R.A.L.E lung sound database. The pulmonary acoustic signals were manually categorised into three different groups, namely normal, airway obstruction pathology, and parenchymal pathology. The mel-frequency cepstral coefficient (MFCC) features were extracted from the pre-processed pulmonary acoustic signals. The MFCC features were analysed by one-way ANOVA and then fed separately into the SVM and K-nn classifiers. The performances of the classifiers were analysed using the confusion matrix technique. The statistical analysis of the MFCC features using one-way ANOVA showed that the extracted MFCC features are significantly different (p < 0.001). The classification accuracies of the SVM and K-nn classifiers were found to be 92.19% and 98.26%, respectively. Conclusion Although the data used to train and test the classifiers are limited, the classification accuracies found are satisfactory. The K-nn classifier was better than the SVM classifier for the discrimination of pulmonary acoustic signals from pathological and normal subjects obtained from the RALE database. PMID:24970564

Estimating animal population density using passive acoustics.

PubMed

Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

2013-05-01

, amphibians, and insects, especially in situations where inferences are required over long periods of time. There is considerable work ahead, with several potentially fruitful research areas, including the development of (i) hardware and software for data acquisition, (ii) efficient, calibrated, automated detection and classification systems, and (iii) statistical approaches optimized for this application. Further, survey design will need to be developed, and research is needed on the acoustic behaviour of target species. Fundamental research on vocalization rates and group sizes, and the relation between these and other factors such as season or behaviour state, is critical. Evaluation of the methods under known density scenarios will be important for empirically validating the approaches presented here. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

Estimating animal population density using passive acoustics

PubMed Central

Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

2013-01-01

, amphibians, and insects, especially in situations where inferences are required over long periods of time. There is considerable work ahead, with several potentially fruitful research areas, including the development of (i) hardware and software for data acquisition, (ii) efficient, calibrated, automated detection and classification systems, and (iii) statistical approaches optimized for this application. Further, survey design will need to be developed, and research is needed on the acoustic behaviour of target species. Fundamental research on vocalization rates and group sizes, and the relation between these and other factors such as season or behaviour state, is critical. Evaluation of the methods under known density scenarios will be important for empirically validating the approaches presented here. PMID:23190144

Automation method to identify the geological structure of seabed using spatial statistic analysis of echo sounding data

NASA Astrophysics Data System (ADS)

Kwon, O.; Kim, W.; Kim, J.

2017-12-01

Recently construction of subsea tunnel has been increased globally. For safe construction of subsea tunnel, identifying the geological structure including fault at design and construction stage is more than important. Then unlike the tunnel in land, it's very difficult to obtain the data on geological structure because of the limit in geological survey. This study is intended to challenge such difficulties in a way of developing the technology to identify the geological structure of seabed automatically by using echo sounding data. When investigation a potential site for a deep subsea tunnel, there is the technical and economical limit with borehole of geophysical investigation. On the contrary, echo sounding data is easily obtainable while information reliability is higher comparing to above approaches. This study is aimed at developing the algorithm that identifies the large scale of geological structure of seabed using geostatic approach. This study is based on theory of structural geology that topographic features indicate geological structure. Basic concept of algorithm is outlined as follows; (1) convert the seabed topography to the grid data using echo sounding data, (2) apply the moving window in optimal size to the grid data, (3) estimate the spatial statistics of the grid data in the window area, (4) set the percentile standard of spatial statistics, (5) display the values satisfying the standard on the map, (6) visualize the geological structure on the map. The important elements in this study include optimal size of moving window, kinds of optimal spatial statistics and determination of optimal percentile standard. To determine such optimal elements, a numerous simulations were implemented. Eventually, user program based on R was developed using optimal analysis algorithm. The user program was designed to identify the variations of various spatial statistics. It leads to easy analysis of geological structure depending on variation of spatial statistics

Agent Collaborative Target Localization and Classification in Wireless Sensor Networks

PubMed Central

Wang, Xue; Bi, Dao-wei; Ding, Liang; Wang, Sheng

2007-01-01

Wireless sensor networks (WSNs) are autonomous networks that have been frequently deployed to collaboratively perform target localization and classification tasks. Their autonomous and collaborative features resemble the characteristics of agents. Such similarities inspire the development of heterogeneous agent architecture for WSN in this paper. The proposed agent architecture views WSN as multi-agent systems and mobile agents are employed to reduce in-network communication. According to the architecture, an energy based acoustic localization algorithm is proposed. In localization, estimate of target location is obtained by steepest descent search. The search algorithm adapts to measurement environments by dynamically adjusting its termination condition. With the agent architecture, target classification is accomplished by distributed support vector machine (SVM). Mobile agents are employed for feature extraction and distributed SVM learning to reduce communication load. Desirable learning performance is guaranteed by combining support vectors and convex hull vectors. Fusion algorithms are designed to merge SVM classification decisions made from various modalities. Real world experiments with MICAz sensor nodes are conducted for vehicle localization and classification. Experimental results show the proposed agent architecture remarkably facilitates WSN designs and algorithm implementation. The localization and classification algorithms also prove to be accurate and energy efficient.

Geological and Geochemical Analysis of Seabed Stability at the Norfolk Ocean Disposal Site. Part 1: Geological Analysis.

DTIC Science & Technology

1983-05-31

ANALYSIS OF SEABED STABILITY AT THE NORFOLK OCEAN DISPOSAL SITE PART 1: GEOLOGICAL ANALYSIS U LU D George F. Oertel, Principal Investigator i- Final Report...eC.it ,ie _. _ r. .. .... All e d !t-o i’~$ ~- - - • ° . .. • : " . o . . . , . . ... - . • , .. . . . . . kkN 4. 18. parameters, diver reconnaissance of...For the period ending September 30, 1982 Prepared for the Department of the Army Norfolk District, Corps of Engineers 803 Front Street D I *Norfolk

Texture as a basis for acoustic classification of substrate in the nearshore region

NASA Astrophysics Data System (ADS)

Dennison, A.; Wattrus, N. J.

2016-12-01

Segmentation and classification of substrate type from two locations in Lake Superior, are predicted using multivariate statistical processing of textural measures derived from shallow-water, high-resolution multibeam bathymetric data. During a multibeam sonar survey, both bathymetric and backscatter data are collected. It is well documented that the statistical characteristic of a sonar backscatter mosaic is dependent on substrate type. While classifying the bottom-type on the basis on backscatter alone can accurately predict and map bottom-type, it lacks the ability to resolve and capture fine textural details, an important factor in many habitat mapping studies. Statistical processing can capture the pertinent details about the bottom-type that are rich in textural information. Further multivariate statistical processing can then isolate characteristic features, and provide the basis for an accurate classification scheme. Preliminary results from an analysis of bathymetric data and ground-truth samples collected from the Amnicon River, Superior, Wisconsin, and the Lester River, Duluth, Minnesota, demonstrate the ability to process and develop a novel classification scheme of the bottom type in two geomorphologically distinct areas.

A constant flux of diverse thermophilic bacteria into the cold Arctic seabed.

PubMed

Hubert, Casey; Loy, Alexander; Nickel, Maren; Arnosti, Carol; Baranyi, Christian; Brüchert, Volker; Ferdelman, Timothy; Finster, Kai; Christensen, Flemming Mønsted; Rosa de Rezende, Júlia; Vandieken, Verona; Jørgensen, Bo Barker

2009-09-18

Microorganisms have been repeatedly discovered in environments that do not support their metabolic activity. Identifying and quantifying these misplaced organisms can reveal dispersal mechanisms that shape natural microbial diversity. Using endospore germination experiments, we estimated a stable supply of thermophilic bacteria into permanently cold Arctic marine sediment at a rate exceeding 10(8) spores per square meter per year. These metabolically and phylogenetically diverse Firmicutes show no detectable activity at cold in situ temperatures but rapidly mineralize organic matter by hydrolysis, fermentation, and sulfate reduction upon induction at 50 degrees C. The closest relatives to these bacteria come from warm subsurface petroleum reservoir and ocean crust ecosystems, suggesting that seabed fluid flow from these environments is delivering thermophiles to the cold ocean. These transport pathways may broadly influence microbial community composition in the marine environment.

Recent developments in seismic seabed oil reservoir monitoring applications using fibre-optic sensing networks

NASA Astrophysics Data System (ADS)

De Freitas, J. M.

2011-05-01

This review looks at recent developments in seismic seabed oil reservoir monitoring techniques using fibre-optic sensing networks. After a brief introduction covering the background and scope of the review, the following section focuses on state-of-the-art fibre-optic hydrophones and accelerometers used for seismic applications. Related metrology aspects of the sensor such as measurement of sensitivity, noise and cross-axis performance are addressed. The third section focuses on interrogation systems. Two main phase-based competing systems have emerged over the past two decades for seismic applications, with a third technique showing much promise; these have been compared in terms of general performance.

Multimodal integration of micro-Doppler sonar and auditory signals for behavior classification with convolutional networks.

PubMed

Dura-Bernal, Salvador; Garreau, Guillaume; Georgiou, Julius; Andreou, Andreas G; Denham, Susan L; Wennekers, Thomas

2013-10-01

The ability to recognize the behavior of individuals is of great interest in the general field of safety (e.g. building security, crowd control, transport analysis, independent living for the elderly). Here we report a new real-time acoustic system for human action and behavior recognition that integrates passive audio and active micro-Doppler sonar signatures over multiple time scales. The system architecture is based on a six-layer convolutional neural network, trained and evaluated using a dataset of 10 subjects performing seven different behaviors. Probabilistic combination of system output through time for each modality separately yields 94% (passive audio) and 91% (micro-Doppler sonar) correct behavior classification; probabilistic multimodal integration increases classification performance to 98%. This study supports the efficacy of micro-Doppler sonar systems in characterizing human actions, which can then be efficiently classified using ConvNets. It also demonstrates that the integration of multiple sources of acoustic information can significantly improve the system's performance.

Semidiurnal Temperature Changes Caused by Tidal Front Movements in the Warm Season in Seabed Habitats on the Georges Bank Northern Margin and Their Ecological Implications

PubMed Central

Guida, Vincent G.; Valentine, Page C.; Gallea, Leslie B.

2013-01-01

Georges Bank is a large, shallow feature separating the Gulf of Maine from the Atlantic Ocean. Previous studies demonstrated a strong tidal-mixing front during the warm season on the northern bank margin between thermally stratified water in the Gulf of Maine and mixed water on the bank. Tides transport warm water off the bank during flood tide and cool gulf water onto the bank during ebb tide. During 10 days in August 2009, we mapped frontal temperatures in five study areas along ∼100 km of the bank margin. The seabed “frontal zone”, where temperature changed with frontal movment, experienced semidiurnal temperature maxima and minima. The tidal excursion of the frontal boundary between stratified and mixed water ranged 6 to 10 km. This “frontal boundary zone” was narrower than the frontal zone. Along transects perpendicular to the bank margin, seabed temperature change at individual sites ranged from 7.0°C in the frontal zone to 0.0°C in mixed bank water. At time series in frontal zone stations, changes during tidal cycles ranged from 1.2 to 6.1°C. The greatest rate of change (−2.48°C hr−1) occurred at mid-ebb. Geographic plots of seabed temperature change allowed the mapping of up to 8 subareas in each study area. The magnitude of temperature change in a subarea depended on its location in the frontal zone. Frontal movement had the greatest effect on seabed temperature in the 40 to 80 m depth interval. Subareas experiencing maximum temperature change in the frontal zone were not in the frontal boundary zone, but rather several km gulfward (off-bank) of the frontal boundary zone. These results provide a new ecological framework for examining the effect of tidally-driven temperature variability on the distribution, food resources, and reproductive success of benthic invertebrate and demersal fish species living in tidal front habitats. PMID:23405129

Semidiurnal temperature changes caused by tidal front movements in the warm season in seabed habitats on the georges bank northern margin and their ecological implications.

PubMed

Guida, Vincent G; Valentine, Page C; Gallea, Leslie B

2013-01-01

Georges Bank is a large, shallow feature separating the Gulf of Maine from the Atlantic Ocean. Previous studies demonstrated a strong tidal-mixing front during the warm season on the northern bank margin between thermally stratified water in the Gulf of Maine and mixed water on the bank. Tides transport warm water off the bank during flood tide and cool gulf water onto the bank during ebb tide. During 10 days in August 2009, we mapped frontal temperatures in five study areas along ∼100 km of the bank margin. The seabed "frontal zone", where temperature changed with frontal movment, experienced semidiurnal temperature maxima and minima. The tidal excursion of the frontal boundary between stratified and mixed water ranged 6 to 10 km. This "frontal boundary zone" was narrower than the frontal zone. Along transects perpendicular to the bank margin, seabed temperature change at individual sites ranged from 7.0°C in the frontal zone to 0.0°C in mixed bank water. At time series in frontal zone stations, changes during tidal cycles ranged from 1.2 to 6.1°C. The greatest rate of change (-2.48°C hr(-1)) occurred at mid-ebb. Geographic plots of seabed temperature change allowed the mapping of up to 8 subareas in each study area. The magnitude of temperature change in a subarea depended on its location in the frontal zone. Frontal movement had the greatest effect on seabed temperature in the 40 to 80 m depth interval. Subareas experiencing maximum temperature change in the frontal zone were not in the frontal boundary zone, but rather several km gulfward (off-bank) of the frontal boundary zone. These results provide a new ecological framework for examining the effect of tidally-driven temperature variability on the distribution, food resources, and reproductive success of benthic invertebrate and demersal fish species living in tidal front habitats.

Semidiurnal temperature changes caused by tidal front movements in the warm season in seabed habitats on the Georges Bank northern margin and their ecological implications

USGS Publications Warehouse

Guida, Vincent G.; Valentine, Page C.; Gallea, Leslie B.

2013-01-01

Georges Bank is a large, shallow feature separating the Gulf of Maine from the Atlantic Ocean. Previous studies demonstrated a strong tidal-mixing front during the warm season on the northern bank margin between thermally stratified water in the Gulf of Maine and mixed water on the bank. Tides transport warm water off the bank during flood tide and cool gulf water onto the bank during ebb tide. During 10 days in August 2009, we mapped frontal temperatures in five study areas along ∼100 km of the bank margin. The seabed “frontal zone”, where temperature changed with frontal movment, experienced semidiurnal temperature maxima and minima. The tidal excursion of the frontal boundary between stratified and mixed water ranged 6 to 10 km. This “frontal boundary zone” was narrower than the frontal zone. Along transects perpendicular to the bank margin, seabed temperature change at individual sites ranged from 7.0°C in the frontal zone to 0.0°C in mixed bank water. At time series in frontal zone stations, changes during tidal cycles ranged from 1.2 to 6.1°C. The greatest rate of change (-2.48°C hr-1) occurred at mid-ebb. Geographic plots of seabed temperature change allowed the mapping of up to 8 subareas in each study area. The magnitude of temperature change in a subarea depended on its location in the frontal zone. Frontal movement had the greatest effect on seabed temperature in the 40 to 80 m depth interval. Subareas experiencing maximum temperature change in the frontal zone were not in the frontal boundary zone, but rather several km gulfward (off-bank) of the frontal boundary zone. These results provide a new ecological framework for examining the effect of tidally-driven temperature variability on the distribution, food resources, and reproductive success of benthic invertebrate and demersal fish species living in tidal front habitats.

Broadband Acoustic Clutter

DTIC Science & Technology

2006-09-30

DRDC-A, and the NATO Undersea Research Centre, La Spezia Italy (this is ongoing). Under these main topics, accomplishments included: a...associated with clutter from an undersea ridge and mud volcano cluster. RESULTS A constrained comparison of waveguide reverberation theory and...1000 Hz c) 0 10 20 −70 −60 −50 −40 −30 −20 −10 Angle (deg) S ca tte rin g S tr en gt h (d B ) 900 Hz a) Figure 1. Measured (x) seabed a

Simulation of vehicle acoustics in support of netted sensor research and development

NASA Astrophysics Data System (ADS)

Christou, Carol T.; Jacyna, Garry M.

2005-05-01

The MITRE Corporation has initiated a three-year internally-funded research program in netted sensors, the first-year effort focusing on vehicle detection for border monitoring. An important component is developing an understanding of the complex acoustic structure of vehicle noise to aid in netted sensor-based detection and classification. This presentation will discuss the design of a high-fidelity vehicle acoustic simulator to model the generation and transmission of acoustic energy from a moving vehicle to a collection of sensor nodes. Realistic spatially-dependent automobile sounds are generated from models of the engine cylinder firing rates, muffler and manifold resonances, and speed-dependent tire whine noise. Tire noise is the dominant noise source for vehicle speeds in excess of 30 miles per hour (MPH). As a result, we have developed detailed models that successfully predict the tire noise spectrum as a function of speed, road surface wave-number spectrum, tire geometry, and tire tread pattern. We have also included realistic descriptions of the spatial directivity patterns for the engine harmonics, muffler, and tire whine noise components. The acoustic waveforms are propagated to each sensor node using a simple phase-dispersive multi-path model. A brief description of the models and their corresponding outputs is provided.

Marine mammal tracks from two-hydrophone acoustic recordings made with a glider

NASA Astrophysics Data System (ADS)

Küsel, Elizabeth T.; Munoz, Tessa; Siderius, Martin; Mellinger, David K.; Heimlich, Sara

2017-04-01

A multinational oceanographic and acoustic sea experiment was carried out in the summer of 2014 off the western coast of the island of Sardinia, Mediterranean Sea. During this experiment, an underwater glider fitted with two hydrophones was evaluated as a potential tool for marine mammal population density estimation studies. An acoustic recording system was also tested, comprising an inexpensive, off-the-shelf digital recorder installed inside the glider. Detection and classification of sounds produced by whales and dolphins, and sometimes tracking and localization, are inherent components of population density estimation from passive acoustics recordings. In this work we discuss the equipment used as well as analysis of the data obtained, including detection and estimation of bearing angles. A human analyst identified the presence of sperm whale (Physeter macrocephalus) regular clicks as well as dolphin clicks and whistles. Cross-correlating clicks recorded on both data channels allowed for the estimation of the direction (bearing) of clicks, and realization of animal tracks. Insights from this bearing tracking analysis can aid in population density estimation studies by providing further information (bearings), which can improve estimates.

Topological Acoustics

NASA Astrophysics Data System (ADS)

Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile

2015-03-01

The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.

Multichannel analysis of surface-waves and integration of downhole acoustic televiewer imaging, ultrasonic Vs and Vp, and vertical seismic profiling in an NEHRP-standard classification, South of Concordia, Kansas, USA

NASA Astrophysics Data System (ADS)

Raef, Abdelmoneam; Gad, Sabreen; Tucker-Kulesza, Stacey

2015-10-01

Seismic site characteristics, as pertaining to earthquake hazard reduction, are a function of the subsurface elastic moduli and the geologic structures. This study explores how multiscale (surface, downhole, and laboratory) datasets can be utilized to improve "constrained" average Vs30 (shear-wave velocity to a 30-meter depth). We integrate borehole, surface and laboratory measurements for a seismic site classification based on the standards of the National Earthquake Hazard Reduction Program (NEHRP). The seismic shear-wave velocity (Vs30) was derived from a geophysical inversion workflow that utilized multichannel analysis of surface-waves (MASW) and downhole acoustic televiewer imaging (DATI). P-wave and S-wave velocities, based on laboratory measurements of arrival times of ultrasonic-frequency signals, supported the workflow by enabling us to calculate Poisson's ratio, which was incorporated in building an initial model for the geophysical inversion of MASW. Extraction of core samples from two boreholes provided lithology and thickness calibration of the amplitudes of the acoustic televiewer imaging for each layer. The MASW inversion, for calculating Vs sections, was constrained with both ultrasonic laboratory measurements (from first arrivals of Vs and Vp waveforms at simulated in situ overburden stress conditions) and the downhole acoustic televiewer (DATV) amplitude logs. The Vs30 calculations enabled categorizing the studied site as NEHRP-class "C" - very dense soil and soft rock. Unlike shallow fractured carbonates in the studied area, S-wave and P-wave velocities at ultrasonic frequency for the deeper intact shale core-samples from two boreholes were in better agreement with the corresponding velocities from both a zero-offset vertical seismic profiling (VSP) and inversion of Rayleigh-wave velocity dispersion curves.

Acoustic sensors using microstructures tunable with energy other than acoustic energy

DOEpatents

Datskos, Panagiotis G.

2003-11-25

A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

Acoustic sensors using microstructures tunable with energy other than acoustic energy

DOEpatents

Datskos, Panagiotis G.

2005-06-07

A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

Acoustic dispersive prism.

PubMed

Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R

2016-01-07

The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz-1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium.

Back-barrier and seabed sediment dynamics in the Albemarle-Pamlico estuarine system, North Carolina

NASA Astrophysics Data System (ADS)

Walsh, J. P.; Corbett, D. R.

2016-02-01

Estuaries are critical habitats as well as places where people live, recreate, and make their livelihood. Additionally, they are sites where land and sea interact, and sediments, and associated pollutants and carbon, are deposited, remobilized and accumulated. Many processes, such as river discharge, waves, tides, and sea-level rise, are operating in estuaries to cause sediment dynamics, impacting humans and organisms as a result. Recent research we have been engaged in across the Albemarle-Pamlico Estuarine System (APES) has investigated the sediments dynamics of this important estuary. The APES is the second largest estuary in the continental United States, consisting of the Albemarle and Pamlico sounds and the Pamlico River and Neuse River sub-estuaries. Although expansive in size, the system is shallow with minimal tidal range. Water and sediment discharge into the APES is modest, and the existence of few inlets along the Outer Banks limits mixing with the Atlantic Ocean. Human impact on the drainage basin and estuarine system is moderate and increasing over time. Over the last five years, a considerable volume of sedimentary process data has been collected over various timescales and locations in the APES. More specifically, work has included: deployments of instrumented tripods to examine seabed dynamics; collection and analysis of shallow cores and GIS investigation of aerial photographs and other data. This wealth of data highlights several insights: 1) shorelines are generally eroding ( 0.25 m/y and rapidly >3 m/y in places), but rates are temporally and spatially variable; 2) seabed resuspension is frequent, yet net accumulation of 2-4 mm/y is widespread in deeper locations; and 3) storms cause episodic, localized impacts (e.g., barrier breaches) on this large, shallow estuarine system.

Automatic classification of killer whale vocalizations using dynamic time warping.

PubMed

Brown, Judith C; Miller, Patrick J O

2007-08-01

A set of killer whale sounds from Marineland were recently classified automatically [Brown et al., J. Acoust. Soc. Am. 119, EL34-EL40 (2006)] into call types using dynamic time warping (DTW), multidimensional scaling, and kmeans clustering to give near-perfect agreement with a perceptual classification. Here the effectiveness of four DTW algorithms on a larger and much more challenging set of calls by Northern Resident whales will be examined, with each call consisting of two independently modulated pitch contours and having considerable overlap in contours for several of the perceptual call types. Classification results are given for each of the four algorithms for the low frequency contour (LFC), the high frequency contour (HFC), their derivatives, and weighted sums of the distances corresponding to LFC with HFC, LFC with its derivative, and HFC with its derivative. The best agreement with the perceptual classification was 90% attained by the Sakoe-Chiba algorithm for the low frequency contours alone.

Contraband detection using acoustic technology

NASA Astrophysics Data System (ADS)

George, Robert D.; Gauthier, Ronald D.; Denslow, Kayte D.; Cinson, Anthony M.; Diaz, Aaron A.; Griffin, Molly

2008-03-01

Maritime security personnel have a need for advanced technologies to address issues such as identification, confirmation or classification of substances and materials in sealed containers, both non-invasively and nondestructively in field and first response operations. Such substances include items such as hazardous/flammable liquids, drugs, contraband, and precursor chemicals used in the fabrication of illicit materials. Our initial efforts focused specifically on a commercial portable acoustic detector technology that was evaluated under operational conditions in a maritime environment. Technical/operational limitations were identified and enhancements were incorporated that would address these limitations. In this paper, application-specific improvements and performance testing/evaluation results will be described. Such enhancements will provide personnel/users of the detector a significantly more reliable method of screening materials for contraband items that might be hidden in cargo containers.

Acoustic energy harvesting based on a planar acoustic metamaterial

NASA Astrophysics Data System (ADS)

Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

2016-06-01

We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

Panel acoustic contribution analysis.

PubMed

Wu, Sean F; Natarajan, Logesh Kumar

2013-02-01

Formulations are derived to analyze the relative panel acoustic contributions of a vibrating structure. The essence of this analysis is to correlate the acoustic power flow from each panel to the radiated acoustic pressure at any field point. The acoustic power is obtained by integrating the normal component of the surface acoustic intensity, which is the product of the surface acoustic pressure and normal surface velocity reconstructed by using the Helmholtz equation least squares based nearfield acoustical holography, over each panel. The significance of this methodology is that it enables one to analyze and rank relative acoustic contributions of individual panels of a complex vibrating structure to acoustic radiation anywhere in the field based on a single set of the acoustic pressures measured in the near field. Moreover, this approach is valid for both interior and exterior regions. Examples of using this method to analyze and rank the relative acoustic contributions of a scaled vehicle cabin are demonstrated.

Is dust acoustic wave a new plasma acoustic mode?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dwivedi, C.B.

1997-09-01

In this Brief Communication, the claim of the novelty of the dust acoustic wave in a dusty plasma within the constant dust charge model is questioned. Conceptual lacunas behind the claim have been highlighted and appropriate physical arguments have been forwarded against the claim. It is demonstrated that the so-called dust acoustic wave could better be termed as a general acoustic fluctuation response with a dominant characteristic feature of the acoustic-like mode (ALM) fluctuation response reported by Dwivedi {ital et al.} [J. Plasma Phys. {bold 41}, 219 (1989)]. It is suggested that both correct and more usable nomenclature of themore » ALM should be the so-called acoustic mode. {copyright} {ital 1997 American Institute of Physics.}« less

Classifiers utilized to enhance acoustic based sensors to identify round types of artillery/mortar

NASA Astrophysics Data System (ADS)

Grasing, David; Desai, Sachi; Morcos, Amir

2008-04-01

Feature extraction methods based on the statistical analysis of the change in event pressure levels over a period and the level of ambient pressure excitation facilitate the development of a robust classification algorithm. The features reliably discriminates mortar and artillery variants via acoustic signals produced during the launch events. Utilizing acoustic sensors to exploit the sound waveform generated from the blast for the identification of mortar and artillery variants as type A, etcetera through analysis of the waveform. Distinct characteristics arise within the different mortar/artillery variants because varying HE mortar payloads and related charges emphasize varying size events at launch. The waveform holds various harmonic properties distinct to a given mortar/artillery variant that through advanced signal processing and data mining techniques can employed to classify a given type. The skewness and other statistical processing techniques are used to extract the predominant components from the acoustic signatures at ranges exceeding 3000m. Exploiting these techniques will help develop a feature set highly independent of range, providing discrimination based on acoustic elements of the blast wave. Highly reliable discrimination will be achieved with a feedforward neural network classifier trained on a feature space derived from the distribution of statistical coefficients, frequency spectrum, and higher frequency details found within different energy bands. The processes that are described herein extend current technologies, which emphasis acoustic sensor systems to provide such situational awareness.

Acoustic Seal

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor)

2006-01-01

The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

Acoustic seal

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M. (Inventor)

2006-01-01

The invention relates to a sealing device having an acoustic resonator. The acoustic resonator is adapted to create acoustic waveforms to generate a sealing pressure barrier blocking fluid flow from a high pressure area to a lower pressure area. The sealing device permits noncontacting sealing operation. The sealing device may include a resonant-macrosonic-synthesis (RMS) resonator.

100% of the World Ocean Floor Mapped by 2030 - Contribution of the South and West Pacific Regional Data Assembly and Coordination Centre to the Seabed 2030 Initiative

NASA Astrophysics Data System (ADS)

Lamarche, G.; Neil, H.; Stagpoole, V. M.; Greenland, A.; Mackay, K.; Black, J.; Griffin, E.

2017-12-01

The Seabed 2030 SaWPac Centre (South and West Pacific Ocean Regional Data Assembly and Coordination Centre) has been formed to generate new high resolution ocean floor maps of the western and southern Pacific Ocean. The centre is part of the joint Nippon Foundation and the General Bathymetric Chart of the Oceans (GEBCO) initiative to produce a definitive map of the World Ocean floor by 2030, empowering the world to make policy decisions, use the ocean sustainability and undertake scientific research based on detailed bathymetric information of the Earth's seabed. The SaWPac Centre is based at NIWA Wellington (New Zealand) and includes a collaborative partnership with GNS Science and Land Information New Zealand. It is responsible for the region from South America to Australia, north of latitude 50°S to 10° north of the Equator and the western part of the Northern Pacific Ocean to Russia. The region includes the world's deepest trenches and also covers some of the remotest oceans where bathymetric data form existing ship tracks is spaced up to 100 km apart. The challenge for the SaWPac Centre is to collate and combine all the available bathymetric data from the numerous nations that have surveyed in the region. The centre will also promote efforts to collect new data and contribute to map products generated by the Seabed 2030 global mapping project.

NW-MILO Acoustic Data Collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matzner, Shari; Myers, Joshua R.; Maxwell, Adam R.

2010-02-17

There is an enduring requirement to improve our ability to detect potential threats and discriminate these from the legitimate commercial and recreational activity ongoing in the nearshore/littoral portion of the maritime domain. The Northwest Maritime Information and Littoral Operations (NW-MILO) Program at PNNL’s Coastal Security Institute in Sequim, Washington is establishing a methodology to detect and classify these threats - in part through developing a better understanding of acoustic signatures in a near-shore environment. The purpose of the acoustic data collection described here is to investigate the acoustic signatures of small vessels. The data is being recorded continuously, 24 hoursmore » a day, along with radar track data and imagery. The recording began in August 2008, and to date the data contains tens of thousands of signals from small vessels recorded in a variety of environmental conditions. The quantity and variety of this data collection, with the supporting imagery and radar track data, makes it particularly useful for the development of robust acoustic signature models and advanced algorithms for signal classification and information extraction. The underwater acoustic sensing system is part of a multi-modal sensing system that is operating near the mouth of Sequim Bay. Sequim Bay opens onto the Straight of Juan de Fuca, which contains part of the border between the U.S. and Canada. Table 1 lists the specific components used for the NW-MILO system. The acoustic sensor is a hydrophone permanently deployed at a mean depth of about 3 meters. In addition to a hydrophone, the other sensors in the system are a marine radar, an electro-optical (EO) camera and an infra-red (IR) camera. The radar is integrated with a vessel tracking system (VTS) that provides position, speed and heading information. The data from all the sensors is recorded and saved to a central server. The data has been validated in terms of its usability for characterizing the

Speaker verification system using acoustic data and non-acoustic data

DOEpatents

Gable, Todd J [Walnut Creek, CA; Ng, Lawrence C [Danville, CA; Holzrichter, John F [Berkeley, CA; Burnett, Greg C [Livermore, CA

2006-03-21

A method and system for speech characterization. One embodiment includes a method for speaker verification which includes collecting data from a speaker, wherein the data comprises acoustic data and non-acoustic data. The data is used to generate a template that includes a first set of "template" parameters. The method further includes receiving a real-time identity claim from a claimant, and using acoustic data and non-acoustic data from the identity claim to generate a second set of parameters. The method further includes comparing the first set of parameters to the set of parameters to determine whether the claimant is the speaker. The first set of parameters and the second set of parameters include at least one purely non-acoustic parameter, including a non-acoustic glottal shape parameter derived from averaging multiple glottal cycle waveforms.

High-acoustic-impedance tantalum oxide layers for insulating acoustic reflectors.

PubMed

Capilla, Jose; Olivares, Jimena; Clement, Marta; Sangrador, Jesús; Iborra, Enrique; Devos, Arnaud

2012-03-01

This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators.

Efficient source separation algorithms for acoustic fall detection using a microsoft kinect.

PubMed

Li, Yun; Ho, K C; Popescu, Mihail

2014-03-01

Falls have become a common health problem among older adults. In previous study, we proposed an acoustic fall detection system (acoustic FADE) that employed a microphone array and beamforming to provide automatic fall detection. However, the previous acoustic FADE had difficulties in detecting the fall signal in environments where interference comes from the fall direction, the number of interferences exceeds FADE's ability to handle or a fall is occluded. To address these issues, in this paper, we propose two blind source separation (BSS) methods for extracting the fall signal out of the interferences to improve the fall classification task. We first propose the single-channel BSS by using nonnegative matrix factorization (NMF) to automatically decompose the mixture into a linear combination of several basis components. Based on the distinct patterns of the bases of falls, we identify them efficiently and then construct the interference free fall signal. Next, we extend the single-channel BSS to the multichannel case through a joint NMF over all channels followed by a delay-and-sum beamformer for additional ambient noise reduction. In our experiments, we used the Microsoft Kinect to collect the acoustic data in real-home environments. The results show that in environments with high interference and background noise levels, the fall detection performance is significantly improved using the proposed BSS approaches.

Accurate positioning based on acoustic and optical sensors

NASA Astrophysics Data System (ADS)

Cai, Kerong; Deng, Jiahao; Guo, Hualing

2009-11-01

Unattended laser target designator (ULTD) was designed to partly take the place of conventional LTDs for accurate positioning and laser marking. Analyzed the precision, accuracy and errors of acoustic sensor array, the requirements of laser generator, and the technology of image analysis and tracking, the major system modules were determined. The target's classification, velocity and position can be measured by sensors, and then coded laser beam will be emitted intelligently to mark the excellent position at the excellent time. The conclusion shows that, ULTD can not only avoid security threats, be deployed massively, and accomplish battle damage assessment (BDA), but also be fit for information-based warfare.

Impact of Acoustic Standing Waves on Structural Responses: Reverberant Acoustic Testing (RAT) vs. Direct Field Acoustic Testing (DFAT)

NASA Technical Reports Server (NTRS)

Kolaini, Ali R.; Doty, Benjamin; Chang, Zensheu

2012-01-01

Loudspeakers have been used for acoustic qualification of spacecraft, reflectors, solar panels, and other acoustically responsive structures for more than a decade. Limited measurements from some of the recent speaker tests used to qualify flight hardware have indicated significant spatial variation of the acoustic field within the test volume. Also structural responses have been reported to differ when similar tests were performed using reverberant chambers. To address the impact of non-uniform acoustic field on structural responses, a series of acoustic tests were performed using a flat panel and a 3-ft cylinder exposed to the field controlled by speakers and repeated in a reverberant chamber. The speaker testing was performed using multi-input-single-output (MISO) and multi-input-multi-output (MIMO) control schemes with and without the test articles. In this paper the spatial variation of the acoustic field due to acoustic standing waves and their impacts on the structural responses in RAT and DFAT (both using MISO and MIMO controls for DFAT) are discussed in some detail.

An acoustic switch.

PubMed

Vanhille, Christian; Campos-Pozuelo, Cleofé

2014-01-01

The benefits derived from the development of acoustic transistors which act as switches or amplifiers have been reported in the literature. Here we propose a model of acoustic switch. We theoretically demonstrate that the device works: the input signal is totally restored at the output when the switch is on whereas the output signal nulls when the switch is off. The switch, on or off, depends on a secondary acoustic field capable to manipulate the main acoustic field. The model relies on the attenuation effect of many oscillating bubbles on the main travelling wave in the liquid, as well as on the capacity of the secondary acoustic wave to move the bubbles. This model evidences the concept of acoustic switch (transistor) with 100% efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

Acoustic tweezers via sub-time-of-flight regime surface acoustic waves.

PubMed

Collins, David J; Devendran, Citsabehsan; Ma, Zhichao; Ng, Jia Wei; Neild, Adrian; Ai, Ye

2016-07-01

Micrometer-scale acoustic waves are highly useful for refined optomechanical and acoustofluidic manipulation, where these fields are spatially localized along the transducer aperture but not along the acoustic propagation direction. In the case of acoustic tweezers, such a conventional acoustic standing wave results in particle and cell patterning across the entire width of a microfluidic channel, preventing selective trapping. We demonstrate the use of nanosecond-scale pulsed surface acoustic waves (SAWs) with a pulse period that is less than the time of flight between opposing transducers to generate localized time-averaged patterning regions while using conventional electrode structures. These nodal positions can be readily and arbitrarily positioned in two dimensions and within the patterning region itself through the imposition of pulse delays, frequency modulation, and phase shifts. This straightforward concept adds new spatial dimensions to which acoustic fields can be localized in SAW applications in a manner analogous to optical tweezers, including spatially selective acoustic tweezers and optical waveguides.

Acoustic levitation of an object larger than the acoustic wavelength.

PubMed

Andrade, Marco A B; Okina, Fábio T A; Bernassau, Anne L; Adamowski, Julio C

2017-06-01

Levitation and manipulation of objects by sound waves have a wide range of applications in chemistry, biology, material sciences, and engineering. However, the current acoustic levitation techniques are mainly restricted to particles that are much smaller than the acoustic wavelength. In this work, it is shown that acoustic standing waves can be employed to stably levitate an object much larger than the acoustic wavelength in air. The levitation of a large slightly curved object weighting 2.3 g is demonstrated by using a device formed by two 25 kHz ultrasonic Langevin transducers connected to an aluminum plate. The sound wave emitted by the device provides a vertical acoustic radiation force to counteract gravity and a lateral restoring force that ensure horizontal stability to the levitated object. In order to understand the levitation stability, a numerical model based on the finite element method is used to determine the acoustic radiation force that acts on the object.

ACOUSTICS IN ARCHITECTURAL DESIGN, AN ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS.

ERIC Educational Resources Information Center

DOELLE, LESLIE L.

THE PURPOSE OF THIS ANNOTATED BIBLIOGRAPHY ON ARCHITECTURAL ACOUSTICS WAS--(1) TO COMPILE A CLASSIFIED BIBLIOGRAPHY, INCLUDING MOST OF THOSE PUBLICATIONS ON ARCHITECTURAL ACOUSTICS, PUBLISHED IN ENGLISH, FRENCH, AND GERMAN WHICH CAN SUPPLY A USEFUL AND UP-TO-DATE SOURCE OF INFORMATION FOR THOSE ENCOUNTERING ANY ARCHITECTURAL-ACOUSTIC DESIGN…

Textural Analysis and Substrate Classification in the Nearshore Region of Lake Superior Using High-Resolution Multibeam Bathymetry

NASA Astrophysics Data System (ADS)

Dennison, Andrew G.

Classification of the seafloor substrate can be done with a variety of methods. These methods include Visual (dives, drop cameras); mechanical (cores, grab samples); acoustic (statistical analysis of echosounder returns). Acoustic methods offer a more powerful and efficient means of collecting useful information about the bottom type. Due to the nature of an acoustic survey, larger areas can be sampled, and by combining the collected data with visual and mechanical survey methods provide greater confidence in the classification of a mapped region. During a multibeam sonar survey, both bathymetric and backscatter data is collected. It is well documented that the statistical characteristic of a sonar backscatter mosaic is dependent on bottom type. While classifying the bottom-type on the basis on backscatter alone can accurately predict and map bottom-type, i.e a muddy area from a rocky area, it lacks the ability to resolve and capture fine textural details, an important factor in many habitat mapping studies. Statistical processing of high-resolution multibeam data can capture the pertinent details about the bottom-type that are rich in textural information. Further multivariate statistical processing can then isolate characteristic features, and provide the basis for an accurate classification scheme. The development of a new classification method is described here. It is based upon the analysis of textural features in conjunction with ground truth sampling. The processing and classification result of two geologically distinct areas in nearshore regions of Lake Superior; off the Lester River,MN and Amnicon River, WI are presented here, using the Minnesota Supercomputer Institute's Mesabi computing cluster for initial processing. Processed data is then calibrated using ground truth samples to conduct an accuracy assessment of the surveyed areas. From analysis of high-resolution bathymetry data collected at both survey sites is was possible to successfully calculate

AST Launch Vehicle Acoustics

NASA Technical Reports Server (NTRS)

Houston, Janice; Counter, D.; Giacomoni, D.

2015-01-01

The liftoff phase induces acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are then used in the prediction of internal vibration responses of the vehicle and components which result in the qualification levels. Thus, predicting these liftoff acoustic (LOA) environments is critical to the design requirements of any launch vehicle. If there is a significant amount of uncertainty in the predictions or if acoustic mitigation options must be implemented, a subscale acoustic test is a feasible pre-launch test option to verify the LOA environments. The NASA Space Launch System (SLS) program initiated the Scale Model Acoustic Test (SMAT) to verify the predicted SLS LOA environments and to determine the acoustic reduction with an above deck water sound suppression system. The SMAT was conducted at Marshall Space Flight Center and the test article included a 5% scale SLS vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 250 instruments. The SMAT liftoff acoustic results are presented, findings are discussed and a comparison is shown to the Ares I Scale Model Acoustic Test (ASMAT) results.

Acoustic neuroma

MedlinePlus

... Cerebellopontine angle tumor; Angle tumor; Hearing loss - acoustic; Tinnitus - acoustic ... that makes it hard to hear conversations Ringing ( tinnitus ) in the affected ear Less common symptoms include: ...

Double negative acoustic metastructure for attenuation of acoustic emissions

NASA Astrophysics Data System (ADS)

Kumar, Sanjay; Bhushan, Pulak; Prakash, Om; Bhattacharya, Shantanu

2018-03-01

Acoustic metamaterials hold great potential for attenuation of low frequency acoustic emissions. However, a fundamental challenge is achieving high transmission loss over a broad frequency range. In this work, we report a double negative acoustic metastructure for absorption of low frequency acoustic emissions in an aircraft. This is achieved by utilizing a periodic array of hexagonal cells interconnected with a neck and mounted with an elastic membrane on both ends. An average transmission loss of 56 dB under 500 Hz and an overall absorption of over 48% have been realized experimentally. The negative mass density is derived from the dipolar resonances created as a result of the in-phase movement of the membranes. Further, the negative bulk modulus is ascribed to the combined effect of out-of-phase acceleration of the membranes and the Helmholtz resonator. The proposed metastructure enables absorption of low frequency acoustic emissions with improved functionality that is highly desirable for varied applications.

Reducing the dimensions of acoustic devices using anti-acoustic-null media

NASA Astrophysics Data System (ADS)

Li, Borui; Sun, Fei; He, Sailing

2018-02-01

An anti-acoustic-null medium (anti-ANM), a special homogeneous medium with anisotropic mass density, is designed by transformation acoustics (TA). Anti-ANM can greatly compress acoustic space along the direction of its main axis, where the size compression ratio is extremely large. This special feature can be utilized to reduce the geometric dimensions of classic acoustic devices. For example, the height of a parabolic acoustic reflector can be greatly reduced. We also design a brass-air structure on the basis of the effective medium theory to materialize the anti-ANM in a broadband frequency range. Numerical simulations verify the performance of the proposed anti-ANM.

North Pacific Acoustic Laboratory: Deep Water Acoustic Propagation in the Philippine Sea

DTIC Science & Technology

2016-06-21

the "Special Issue on Deep-water Ocean Acoustics" in the Journal of the Acoustical Society of America (Vol. 134, No . 4, Pt. 2 of 2 , October20 13...also listed. Fourteen (14) of these publications appeared in the " Special Issue on Deep-water Ocean Acoustics" in the Journal of the Acoustical

Automatic intelligibility classification of sentence-level pathological speech

PubMed Central

Kim, Jangwon; Kumar, Naveen; Tsiartas, Andreas; Li, Ming; Narayanan, Shrikanth S.

2014-01-01

Pathological speech usually refers to the condition of speech distortion resulting from atypicalities in voice and/or in the articulatory mechanisms owing to disease, illness or other physical or biological insult to the production system. Although automatic evaluation of speech intelligibility and quality could come in handy in these scenarios to assist experts in diagnosis and treatment design, the many sources and types of variability often make it a very challenging computational processing problem. In this work we propose novel sentence-level features to capture abnormal variation in the prosodic, voice quality and pronunciation aspects in pathological speech. In addition, we propose a post-classification posterior smoothing scheme which refines the posterior of a test sample based on the posteriors of other test samples. Finally, we perform feature-level fusions and subsystem decision fusion for arriving at a final intelligibility decision. The performances are tested on two pathological speech datasets, the NKI CCRT Speech Corpus (advanced head and neck cancer) and the TORGO database (cerebral palsy or amyotrophic lateral sclerosis), by evaluating classification accuracy without overlapping subjects’ data among training and test partitions. Results show that the feature sets of each of the voice quality subsystem, prosodic subsystem, and pronunciation subsystem, offer significant discriminating power for binary intelligibility classification. We observe that the proposed posterior smoothing in the acoustic space can further reduce classification errors. The smoothed posterior score fusion of subsystems shows the best classification performance (73.5% for unweighted, and 72.8% for weighted, average recalls of the binary classes). PMID:25414544

Relationships between objective acoustic indices and acoustic comfort evaluation in nonacoustic spaces

NASA Astrophysics Data System (ADS)

Kang, Jian

2004-05-01

Much attention has been paid to acoustic spaces such as concert halls and recording studios, whereas research on nonacoustic buildings/spaces has been rather limited, especially from the viewpoint of acoustic comfort. In this research a series of case studies has been carried out on this topic, considering various spaces including shopping mall atrium spaces, library reading rooms, football stadia, swimming spaces, churches, dining spaces, as well as urban open public spaces. The studies focus on the relationships between objective acoustic indices such as sound pressure level and reverberation time and perceptions of acoustic comfort. The results show that the acoustic atmosphere is an important consideration in such spaces and the evaluation of acoustic comfort may vary considerably even if the objective acoustic indices are the same. It is suggested that current guidelines and technical regulations are insufficient in terms of acoustic design of these spaces, and the relationships established from the case studies between objective and subjective aspects would be useful for developing further design guidelines. [Work supported partly by the British Academy.

Virtual acoustics displays

NASA Astrophysics Data System (ADS)

Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

1991-03-01

The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

Virtual acoustics displays

NASA Technical Reports Server (NTRS)

Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

1991-01-01

The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

Simulation of Acoustics for Ares I Scale Model Acoustic Tests

NASA Technical Reports Server (NTRS)

Putnam, Gabriel; Strutzenberg, Louise L.

2011-01-01

The Ares I Scale Model Acoustics Test (ASMAT) is a series of live-fire tests of scaled rocket motors meant to simulate the conditions of the Ares I launch configuration. These tests have provided a well documented set of high fidelity acoustic measurements useful for validation including data taken over a range of test conditions and containing phenomena like Ignition Over-Pressure and water suppression of acoustics. To take advantage of this data, a digital representation of the ASMAT test setup has been constructed and test firings of the motor have been simulated using the Loci/CHEM computational fluid dynamics software. Results from ASMAT simulations with the rocket in both held down and elevated configurations, as well as with and without water suppression have been compared to acoustic data collected from similar live-fire tests. Results of acoustic comparisons have shown good correlation with the amplitude and temporal shape of pressure features and reasonable spectral accuracy up to approximately 1000 Hz. Major plume and acoustic features have been well captured including the plume shock structure, the igniter pulse transient, and the ignition overpressure.

Compositional Signatures in Acoustic Backscatter Over Vegetated and Unvegetated Mixed Sand-Gravel Riverbeds

NASA Astrophysics Data System (ADS)

Buscombe, D.; Grams, P. E.; Kaplinski, M. A.

2017-10-01

Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

Compositional signatures in acoustic backscatter over vegetated and unvegetated mixed sand-gravel riverbeds

USGS Publications Warehouse

Buscombe, Daniel; Grams, Paul E.; Kaplinski, Matt A.

2017-01-01

Multibeam acoustic backscatter has considerable utility for remote characterization of spatially heterogeneous bed sediment composition over vegetated and unvegetated riverbeds of mixed sand and gravel. However, the use of high-frequency, decimeter-resolution acoustic backscatter for sediment classification in shallow water is hampered by significant topographic contamination of the signal. In mixed sand-gravel riverbeds, changes in the abiotic composition of sediment (such as homogeneous sand to homogeneous gravel) tend to occur over larger spatial scales than is characteristic of small-scale bedform topography (ripples, dunes, and bars) or biota (such as vascular plants and periphyton). A two-stage method is proposed to filter out the morphological contributions to acoustic backscatter. First, the residual supragrain-scale topographic effects in acoustic backscatter with small instantaneous insonified areas, caused by ambiguity in the local (beam-to-beam) bed-sonar geometry, are removed. Then, coherent scales between high-resolution topography and backscatter are identified using cospectra, which are used to design a frequency domain filter that decomposes backscatter into the (unwanted) high-pass component associated with bedform topography (ripples, dunes, and sand waves) and vegetation, and the (desired) low-frequency component associated with the composition of sediment patches superimposed on the topography. This process strengthens relationships between backscatter and sediment composition. A probabilistic framework is presented for classifying vegetated and unvegetated substrates based on acoustic backscatter at decimeter resolution. This capability is demonstrated using data collected from diverse settings within a 386 km reach of a canyon river whose bed varies among sand, gravel, cobbles, boulders, and submerged vegetation.

DARPA counter-sniper program: Phase 1 Acoustic Systems Demonstration results

NASA Astrophysics Data System (ADS)

Carapezza, Edward M.; Law, David B.; Csanadi, Christina J.

1997-02-01

During October 1995 through May 1996, the Defense Advanced Research Projects Agency sponsored the development of prototype systems that exploit acoustic muzzle blast and ballistic shock wave signatures to accurately predict the location of gunfire events and associated shooter locations using either single or multiple volumetric arrays. The output of these acoustic systems is an estimate of the shooter location and a classification estimate of the caliber of the shooter's weapon. A portable display and control unit provides both graphical and alphanumeric shooter location related information integrated on a two- dimensional digital map of the defended area. The final Phase I Acoustic Systems Demonstration field tests were completed in May. These these tests were held at USMC Base Camp Pendleton Military Operations Urban Training (MOUT) facility. These tests were structured to provide challenging gunfire related scenarios with significant reverberation and multi-path conditions. Special shot geometries and false alarms were included in these tests to probe potential system vulnerabilities and to determine the performance and robustness of the systems. Five prototypes developed by U.S. companies and one Israeli developed prototype were tested. This analysis quantifies the spatial resolution estimation capability (azimuth, elevation and range) of these prototypes and describes their ability to accurately classify the type of bullet fired in a challenging urban- like setting.

DARHT Multi-intelligence Seismic and Acoustic Data Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevens, Garrison Nicole; Van Buren, Kendra Lu; Hemez, Francois M.

The purpose of this report is to document the analysis of seismic and acoustic data collected at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory for robust, multi-intelligence decision making. The data utilized herein is obtained from two tri-axial seismic sensors and three acoustic sensors, resulting in a total of nine data channels. The goal of this analysis is to develop a generalized, automated framework to determine internal operations at DARHT using informative features extracted from measurements collected external of the facility. Our framework involves four components: (1) feature extraction, (2) data fusion, (3) classification, andmore » finally (4) robustness analysis. Two approaches are taken for extracting features from the data. The first of these, generic feature extraction, involves extraction of statistical features from the nine data channels. The second approach, event detection, identifies specific events relevant to traffic entering and leaving the facility as well as explosive activities at DARHT and nearby explosive testing sites. Event detection is completed using a two stage method, first utilizing signatures in the frequency domain to identify outliers and second extracting short duration events of interest among these outliers by evaluating residuals of an autoregressive exogenous time series model. Features extracted from each data set are then fused to perform analysis with a multi-intelligence paradigm, where information from multiple data sets are combined to generate more information than available through analysis of each independently. The fused feature set is used to train a statistical classifier and predict the state of operations to inform a decision maker. We demonstrate this classification using both generic statistical features and event detection and provide a comparison of the two methods. Finally, the concept of decision robustness is presented through a preliminary

Repertoire and classification of non-song calls in Southeast Alaskan humpback whales (Megaptera novaeangliae).

PubMed

Fournet, Michelle E; Szabo, Andy; Mellinger, David K

2015-01-01

On low-latitude breeding grounds, humpback whales produce complex and highly stereotyped songs as well as a range of non-song sounds associated with breeding behaviors. While on their Southeast Alaskan foraging grounds, humpback whales produce a range of previously unclassified non-song vocalizations. This study investigates the vocal repertoire of Southeast Alaskan humpback whales from a sample of 299 non-song vocalizations collected over a 3-month period on foraging grounds in Frederick Sound, Southeast Alaska. Three classification systems were used, including aural spectrogram analysis, statistical cluster analysis, and discriminant function analysis, to describe and classify vocalizations. A hierarchical acoustic structure was identified; vocalizations were classified into 16 individual call types nested within four vocal classes. The combined classification method shows promise for identifying variability in call stereotypy between vocal groupings and is recommended for future classification of broad vocal repertoires.

Classification of the Correct Quranic Letters Pronunciation of Male and Female Reciters

NASA Astrophysics Data System (ADS)

Khairuddin, Safiah; Ahmad, Salmiah; Embong, Abdul Halim; Nur Wahidah Nik Hashim, Nik; Altamas, Tareq M. K.; Nuratikah Syd Badaruddin, Syarifah; Shahbudin Hassan, Surul

2017-11-01

Recitation of the Holy Quran with the correct Tajweed is essential for every Muslim. Islam has encouraged Quranic education since early age as the recitation of the Quran correctly will represent the correct meaning of the words of Allah. It is important to recite the Quranic verses according to its characteristics (sifaat) and from its point of articulations (makhraj). This paper presents the identification and classification analysis of Quranic letters pronunciation for both male and female reciters, to obtain the unique representation of each letter by male as compared to female expert reciters. Linear Discriminant Analysis (LDA) was used as the classifier to classify the data with Formants and Power Spectral Density (PSD) as the acoustic features. The result shows that linear classifier of PSD with band 1 and band 2 power spectral combinations gives a high percentage of classification accuracy for most of the Quranic letters. It is also shown that the pronunciation by male reciters gives better result in the classification of the Quranic letters.

Subwavelength diffractive acoustics and wavefront manipulation with a reflective acoustic metasurface

NASA Astrophysics Data System (ADS)

Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.

2016-11-01

Acoustic metasurfaces provide useful wavefront shaping capabilities, such as beam steering, acoustic focusing, and asymmetric transmission, in a compact structure. Most acoustic metasurfaces described in the literature are transmissive devices and focus their performance on steering sound beam of the fundamental diffractive order. In addition, the range of incident angles studied is usually below the critical incidence predicted by generalized Snell's law of reflection. In this work, we comprehensively analyze the wave interaction with a generic periodic phase-modulating structure in order to predict the behavior of all diffractive orders, especially for cases beyond critical incidence. Under the guidance of the presented analysis, a broadband reflective metasurface is designed based on an expanded library of labyrinthine acoustic metamaterials. Various local and nonlocal wavefront shaping properties are experimentally demonstrated, and enhanced absorption of higher order diffractive waves is experimentally shown for the first time. The proposed methodology provides an accurate approach for predicting practical diffracted wave behaviors and opens a new perspective for the study of acoustic periodic structures. The designed metasurface extends the functionalities of acoustic metasurfaces and paves the way for the design of thin planar reflective structures for broadband acoustic wave manipulation and extraordinary absorption.

Sound Classification in Hearing Aids Inspired by Auditory Scene Analysis

NASA Astrophysics Data System (ADS)

Büchler, Michael; Allegro, Silvia; Launer, Stefan; Dillier, Norbert

2005-12-01

A sound classification system for the automatic recognition of the acoustic environment in a hearing aid is discussed. The system distinguishes the four sound classes "clean speech," "speech in noise," "noise," and "music." A number of features that are inspired by auditory scene analysis are extracted from the sound signal. These features describe amplitude modulations, spectral profile, harmonicity, amplitude onsets, and rhythm. They are evaluated together with different pattern classifiers. Simple classifiers, such as rule-based and minimum-distance classifiers, are compared with more complex approaches, such as Bayes classifier, neural network, and hidden Markov model. Sounds from a large database are employed for both training and testing of the system. The achieved recognition rates are very high except for the class "speech in noise." Problems arise in the classification of compressed pop music, strongly reverberated speech, and tonal or fluctuating noises.

Stop-like modification of the dental fricative ∕ð∕: An acoustic analysis

PubMed Central

Zhao, Sherry Y.

2010-01-01

This study concentrates on one of the commonly occurring phonetic variations in English: the stop-like modification of the dental fricative ∕ð∕. The variant exhibits a drastic change from the canonical ∕ð∕; the manner of articulation is changed from one that is fricative to one that is stop-like. Furthermore, the place of articulation of stop-like ∕ð∕ has been a point of uncertainty, leading to confusion between stop-like ∕ð∕ and ∕d/. In this study, acoustic and spectral moment measures were taken from 100 stop-like ∕ð∕ and 102 ∕d/ tokens produced by 59 male and 23 female speakers in the TIMIT corpus. Data analysis indicated that stop-like ∕ð∕ is significantly different from ∕d/ in burst amplitude, burst spectrum shape, burst peak frequency, second formant at following-vowel onset, and spectral moments. Moreover, the acoustic differences from ∕d/ are consistent with those expected for a dental stop-like ∕ð∕. Automatic classification experiments involving these acoustic measures suggested that they are salient in distinguishing stop-like ∕ð∕ from ∕d/. PMID:20968372

Advanced Methods for Passive Acoustic Detection, Classification, and Localization of Marine Mammals

DTIC Science & Technology

2014-09-30

floor 1176 Howell St Newport RI 02842 phone: (401) 832-5749 fax: (401) 832-4441 email: David.Moretti@navy.mil Steve W. Martin SPAWAR...APPROACH Odontocete click detection and classification. A multi-class support vector machine (SVM) classifier was previously developed ( Jarvis ...beaked whales, Risso’s dolphins, short-finned pilot whales, and sperm whales. Here Moretti’s group, particularly S. Jarvis , is improving the SVM

Advanced Methods for Passive Acoustic Detection, Classification, and Localization of Marine Mammals

DTIC Science & Technology

2011-09-30

Newport RI 02842 phone: (401) 832-5749 fax: (401) 832-4441 email: David.Moretti@navy.mil Steve W. Martin SPAWAR Systems Center Pacific...APPROACH Odontocete click detection and classification. A multiclass support vector machine (SVM) classifier was previously developed ( Jarvis et...beaked whales, Risso’s dolphins, short-finned pilot whales, and sperm whales. Here Moretti’s group, especially S. Jarvis , will improve the SVM classifier

Processes of physical change to the seabed and bivalve recruitment over a 10-year period following experimental hydraulic clam dredging on Banquereau, Scotian Shelf

NASA Astrophysics Data System (ADS)

Gilkinson, K.; King, E. L.; Li, M. Z.; Roddick, D.; Kenchington, E.; Han, G.

2015-01-01

A previous study on the effects of experimental hydraulic clam dredging on seabed habitat and commercial bivalve populations revealed a lack of recovery after a 3-year post-dredging period (1998-2001) on a deep (65-75 m) offshore sandy bank on the Scotian Shelf, Canada. Follow-up sidescan sonar surveys were carried out 5 and 10 years after dredging (2003, 2008) in order to identify long-term processes of seabed recovery. Grab sampling was carried out 10 years after dredging to identify post-dredging commercial bivalve recruitment. Changes in the seafloor, including dredge tracks, were documented with a series of 7 sidescan sonar surveys between 1998 and 2008. A sediment mobility model was constructed based on modeled tidal current and hindcast wave data over this time period to quantify natural seabed disturbance and interpret changes to the dredge tracks mapped by sidescan sonar surveys. The model indicated that tidal currents had minimal effect on sediment mobilization. The main driving force associated with re-working of surficial sediments as evidenced by deterioration of dredge tracks in sonograms was annual fall/winter storms. While the annual frequency of storms and associated wave heights was variable, the observations and sediment mobility calculations suggest that the most influential variable is the magnitude of individual large storms, specifically storms with a significant wave height of ∼11 m. These storms are capable of generating mobile sediment layers of 20-30 cm thickness, equivalent to the dredge blade cutting depth. It appears that, with minor exceptions, sediment properties have returned to pre-dredging conditions 10 years after dredging in this habitat. Based on known age-length relationships, the four commercial bivalve species showed very low recruitment at the experimental site over the 10-year post-dredging period. However, this is unlikely due to a dredging effect since a similar pattern was observed in non-dredged areas.

Acoustic Neuroma

MedlinePlus

An acoustic neuroma is a benign tumor that develops on the nerve that connects the ear to the brain. ... can press against the brain, becoming life-threatening. Acoustic neuroma can be difficult to diagnose, because the ...

How many rumbles are there? Acoustic variation and individual identity in the rumble vocalizations of African elephants (Loxodonta africana)

NASA Astrophysics Data System (ADS)

Soltis, Joseph M.; Savage, Anne; Leong, Kirsten M.

2004-05-01

The most commonly occurring elephant vocalization is the rumble, a frequency-modulated call with infrasonic components. Upwards of ten distinct rumble subtypes have been proposed, but little quantitative work on the acoustic properties of rumbles has been conducted. Rumble vocalizations (N=269) from six females housed at Disney's Animal Kingdom were analyzed. Vocalizations were recorded from microphones in collars around subject necks, and rumbles were digitized and measured using SIGNAL software. Sixteen acoustic variables were measured for each call, extracting both source and filter features. Multidimensional scaling analysis indicates that there are no acoustically distinct rumble subtypes, but that there is quantitative variation across rumbles. Discriminant function analysis showed that the acoustic characteristics of rumbles differ across females. A classification success rate of 65% was achieved when assigning unselected rumbles to one of the six females (test set =64 calls) according to the functions derived from the originally selected calls (training set =205 calls). The rumble is best viewed as a single call type with graded variation, but information regarding individual identity is encoded in female rumbles.

Acoustic suspension system

NASA Technical Reports Server (NTRS)

Lee, M. C.; Wang, T. G. (Inventor)

1983-01-01

An acoustic levitation system is described, with single acoustic source and a small reflector to stably levitate a small object while the object is processed as by coating or heating it. The system includes a concave acoustic source which has locations on opposite sides of its axis that vibrate towards and away from a focal point to generate a converging acoustic field. A small reflector is located near the focal point, and preferably slightly beyond it, to create an intense acoustic field that stably supports a small object near the reflector. The reflector is located about one-half wavelength from the focal point and is concavely curved to a radius of curvature (L) of about one-half the wavelength, to stably support an object one-quarter wavelength (N) from the reflector.

Acoustic evaluation of wood quality in standing trees. Part I, Acoustic wave behavior

Treesearch

Xiping Wang; Robert J. Ross; Peter Carter

2007-01-01

Acoustic wave velocities in standing trees or live softwood species were measured by the time-of-flight (TOF) method. Tree velocities were compared with acoustic velocities measured in corresponding butt logs through a resonance acoustic method. The experimental data showed a skewed relationship between tree and log acoustic measurements. For most trees tested,...

Room Acoustics

NASA Astrophysics Data System (ADS)

Kuttruff, Heinrich; Mommertz, Eckard

The traditional task of room acoustics is to create or formulate conditions which ensure the best possible propagation of sound in a room from a sound source to a listener. Thus, objects of room acoustics are in particular assembly halls of all kinds, such as auditoria and lecture halls, conference rooms, theaters, concert halls or churches. Already at this point, it has to be pointed out that these conditions essentially depend on the question if speech or music should be transmitted; in the first case, the criterion for transmission quality is good speech intelligibility, in the other case, however, the success of room-acoustical efforts depends on other factors that cannot be quantified that easily, not least it also depends on the hearing habits of the listeners. In any case, absolutely "good acoustics" of a room do not exist.

Acoustic scaling: A re-evaluation of the acoustic model of Manchester Studio 7

NASA Astrophysics Data System (ADS)

Walker, R.

1984-12-01

The reasons for the reconstruction and re-evaluation of the acoustic scale mode of a large music studio are discussed. The design and construction of the model using mechanical and structural considerations rather than purely acoustic absorption criteria is described and the results obtained are given. The results confirm that structural elements within the studio gave rise to unexpected and unwanted low-frequency acoustic absorption. The results also show that at least for the relatively well understood mechanisms of sound energy absorption physical modelling of the structural and internal components gives an acoustically accurate scale model, within the usual tolerances of acoustic design. The poor reliability of measurements of acoustic absorption coefficients, is well illustrated. The conclusion is reached that such acoustic scale modelling is a valid and, for large scale projects, financially justifiable technique for predicting fundamental acoustic effects. It is not appropriate for the prediction of fine details because such small details are unlikely to be reproduced exactly at a different size without extensive measurements of the material's performance at both scales.

Acoustic Test Characterization of Melamine Foam for Usage in NASA's Payload Fairing Acoustic Attenuation Systems

NASA Technical Reports Server (NTRS)

Hughes, William O.; McNelis, Anne M.; McNelis, Mark E.

2014-01-01

The external acoustic liftoff levels predicted for NASA's future heavy lift launch vehicles are expected to be significantly higher than the environment created by today's commercial launch vehicles. This creates a need to develop an improved acoustic attenuation system for future NASA payload fairings. NASA Glenn Research Center initiated an acoustic test series to characterize the acoustic performance of melamine foam, with and without various acoustic enhancements. This testing was denoted as NEMFAT, which stands for NESC Enhanced Melamine Foam Acoustic Test, and is the subject of this paper. Both absorption and transmission loss testing of numerous foam configurations were performed at the Riverbank Acoustical Laboratory in July 2013. The NEMFAT test data provides an initial acoustic characterization and database of melamine foam for NASA. Because of its acoustic performance and lighter mass relative to fiberglass blankets, melamine foam is being strongly considered for use in the acoustic attenuation systems of NASA's future launch vehicles.

Helmet-mounted acoustic array for hostile fire detection and localization in an urban environment

NASA Astrophysics Data System (ADS)

Scanlon, Michael V.

2008-04-01

The detection and localization of hostile weapons firing has been demonstrated successfully with acoustic sensor arrays on unattended ground sensors (UGS), ground-vehicles, and unmanned aerial vehicles (UAVs). Some of the more mature systems have demonstrated significant capabilities and provide direct support to ongoing counter-sniper operations. The Army Research Laboratory (ARL) is conducting research and development for a helmet-mounted system to acoustically detect and localize small arms firing, or other events such as RPG, mortars, and explosions, as well as other non-transient signatures. Since today's soldier is quickly being asked to take on more and more reconnaissance, surveillance, & target acquisition (RSTA) functions, sensor augmentation enables him to become a mobile and networked sensor node on the complex and dynamic battlefield. Having a body-worn threat detection and localization capability for events that pose an immediate danger to the soldiers around him can significantly enhance their survivability and lethality, as well as enable him to provide and use situational awareness clues on the networked battlefield. This paper addresses some of the difficulties encountered by an acoustic system in an urban environment. Complex reverberation, multipath, diffraction, and signature masking by building structures makes this a very harsh environment for robust detection and classification of shockwaves and muzzle blasts. Multifunctional acoustic detection arrays can provide persistent surveillance and enhanced situational awareness for every soldier.

Plant Classification from Bat-Like Echolocation Signals

PubMed Central

Yovel, Yossi; Franz, Matthias Otto; Stilz, Peter; Schnitzler, Hans-Ulrich

2008-01-01

Classification of plants according to their echoes is an elementary component of bat behavior that plays an important role in spatial orientation and food acquisition. Vegetation echoes are, however, highly complex stochastic signals: from an acoustical point of view, a plant can be thought of as a three-dimensional array of leaves reflecting the emitted bat call. The received echo is therefore a superposition of many reflections. In this work we suggest that the classification of these echoes might not be such a troublesome routine for bats as formerly thought. We present a rather simple approach to classifying signals from a large database of plant echoes that were created by ensonifying plants with a frequency-modulated bat-like ultrasonic pulse. Our algorithm uses the spectrogram of a single echo from which it only uses features that are undoubtedly accessible to bats. We used a standard machine learning algorithm (SVM) to automatically extract suitable linear combinations of time and frequency cues from the spectrograms such that classification with high accuracy is enabled. This demonstrates that ultrasonic echoes are highly informative about the species membership of an ensonified plant, and that this information can be extracted with rather simple, biologically plausible analysis. Thus, our findings provide a new explanatory basis for the poorly understood observed abilities of bats in classifying vegetation and other complex objects. PMID:18369425

Beluga whale (Delphinapterus leucas) vocalizations and call classification from the eastern Beaufort Sea population.

PubMed

Garland, Ellen C; Castellote, Manuel; Berchok, Catherine L

2015-06-01

Beluga whales, Delphinapterus leucas, have a graded call system; call types exist on a continuum making classification challenging. A description of vocalizations from the eastern Beaufort Sea beluga population during its spring migration are presented here, using both a non-parametric classification tree analysis (CART), and a Random Forest analysis. Twelve frequency and duration measurements were made on 1019 calls recorded over 14 days off Icy Cape, Alaska, resulting in 34 identifiable call types with 83% agreement in classification for both CART and Random Forest analyses. This high level of agreement in classification, with an initial subjective classification of calls into 36 categories, demonstrates that the methods applied here provide a quantitative analysis of a graded call dataset. Further, as calls cannot be attributed to individuals using single sensor passive acoustic monitoring efforts, these methods provide a comprehensive analysis of data where the influence of pseudo-replication of calls from individuals is unknown. This study is the first to describe the vocal repertoire of a beluga population using a robust and repeatable methodology. A baseline eastern Beaufort Sea beluga population repertoire is presented here, against which the call repertoire of other seasonally sympatric Alaskan beluga populations can be compared.

Effects of subsampling of passive acoustic recordings on acoustic metrics.

PubMed

Thomisch, Karolin; Boebel, Olaf; Zitterbart, Daniel P; Samaran, Flore; Van Parijs, Sofie; Van Opzeeland, Ilse

2015-07-01

Passive acoustic monitoring is an important tool in marine mammal studies. However, logistics and finances frequently constrain the number and servicing schedules of acoustic recorders, requiring a trade-off between deployment periods and sampling continuity, i.e., the implementation of a subsampling scheme. Optimizing such schemes to each project's specific research questions is desirable. This study investigates the impact of subsampling on the accuracy of two common metrics, acoustic presence and call rate, for different vocalization patterns (regimes) of baleen whales: (1) variable vocal activity, (2) vocalizations organized in song bouts, and (3) vocal activity with diel patterns. To this end, above metrics are compared for continuous and subsampled data subject to different sampling strategies, covering duty cycles between 50% and 2%. The results show that a reduction of the duty cycle impacts negatively on the accuracy of both acoustic presence and call rate estimates. For a given duty cycle, frequent short listening periods improve accuracy of daily acoustic presence estimates over few long listening periods. Overall, subsampling effects are most pronounced for low and/or temporally clustered vocal activity. These findings illustrate the importance of informed decisions when applying subsampling strategies to passive acoustic recordings or analyses for a given target species.

Use of classification trees to apportion single echo detections to species: Application to the pelagic fish community of Lake Superior

USGS Publications Warehouse

Yule, Daniel L.; Adams, Jean V.; Hrabik, Thomas R.; Vinson, Mark R.; Woiak, Zebadiah; Ahrenstroff, Tyler D.

2013-01-01

Acoustic methods are used to estimate the density of pelagic fish in large lakes with results of midwater trawling used to assign species composition. Apportionment in lakes having mixed species can be challenging because only a small fraction of the water sampled acoustically is sampled with trawl gear. Here we describe a new method where single echo detections (SEDs) are assigned to species based on classification tree models developed from catch data that separate species based on fish size and the spatial habitats they occupy. During the summer of 2011, we conducted a spatially-balanced lake-wide acoustic and midwater trawl survey of Lake Superior. A total of 51 sites in four bathymetric depth strata (0–30 m, 30–100 m, 100–200 m, and >200 m) were sampled. We developed classification tree models for each stratum and found fish length was the most important variable for separating species. To apply these trees to the acoustic data, we needed to identify a target strength to length (TS-to-L) relationship appropriate for all abundant Lake Superior pelagic species. We tested performance of 7 general (i.e., multi-species) relationships derived from three published studies. The best-performing relationship was identified by comparing predicted and observed catch compositions using a second independent Lake Superior data set. Once identified, the relationship was used to predict lengths of SEDs from the lake-wide survey, and the classification tree models were used to assign each SED to a species. Exotic rainbow smelt (Osmerus mordax) were the most common species at bathymetric depths 100 m (384 million; 6.0 kt). Cisco (Coregonus artedi) were widely distributed over all strata with their population estimated at 182 million (44 kt). The apportionment method we describe should be transferable to other large lakes provided fish are not tightly aggregated, and an appropriate TS-to-L relationship for abundant pelagic fish species can be determined.

On the Resonant Behavior of a Weakly Compressible Water Layer During Tsunamigenic Earthquakes

NASA Astrophysics Data System (ADS)

Cecioni, Claudia; Bellotti, Giorgio

2018-01-01

Tsunamigenic earthquakes trigger pressure waves in the ocean, given the weak compressibility of the sea water. For particular conditions, a resonant behavior of the water layer can occur, which influences the energy transfer from the sea-bed motion to the ocean. In this paper, the resonance conditions are explained and analyzed, focusing on the hydro-acoustic waves in the proximity of the earthquake area. A preliminary estimation of the generation parameters (sea-bed rising time, velocity) is given, by means of parametric numerical simulations for simplified conditions. The results confirm the importance of measuring, modeling, and interpreting such waves for tsunami early detection and warning.

On the Resonant Behavior of a Weakly Compressible Water Layer During Tsunamigenic Earthquakes

NASA Astrophysics Data System (ADS)

Cecioni, Claudia; Bellotti, Giorgio

2018-04-01

Tsunamigenic earthquakes trigger pressure waves in the ocean, given the weak compressibility of the sea water. For particular conditions, a resonant behavior of the water layer can occur, which influences the energy transfer from the sea-bed motion to the ocean. In this paper, the resonance conditions are explained and analyzed, focusing on the hydro-acoustic waves in the proximity of the earthquake area. A preliminary estimation of the generation parameters (sea-bed rising time, velocity) is given, by means of parametric numerical simulations for simplified conditions. The results confirm the importance of measuring, modeling, and interpreting such waves for tsunami early detection and warning.

An efficient robust sound classification algorithm for hearing aids.

PubMed

Nordqvist, Peter; Leijon, Arne

2004-06-01

An efficient robust sound classification algorithm based on hidden Markov models is presented. The system would enable a hearing aid to automatically change its behavior for differing listening environments according to the user's preferences. This work attempts to distinguish between three listening environment categories: speech in traffic noise, speech in babble, and clean speech, regardless of the signal-to-noise ratio. The classifier uses only the modulation characteristics of the signal. The classifier ignores the absolute sound pressure level and the absolute spectrum shape, resulting in an algorithm that is robust against irrelevant acoustic variations. The measured classification hit rate was 96.7%-99.5% when the classifier was tested with sounds representing one of the three environment categories included in the classifier. False-alarm rates were 0.2%-1.7% in these tests. The algorithm is robust and efficient and consumes a small amount of instructions and memory. It is fully possible to implement the classifier in a DSP-based hearing instrument.

Acoustical and optical radiation pressure and the development of single beam acoustical tweezers

NASA Astrophysics Data System (ADS)

Thomas, Jean-Louis; Marchiano, Régis; Baresch, Diego

2017-07-01

Studies on radiation pressure in acoustics and optics have enriched one another and have a long common history. Acoustic radiation pressure is used for metrology, levitation, particle trapping and actuation. However, the dexterity and selectivity of single-beam optical tweezers are still to be matched with acoustical devices. Optical tweezers can trap, move and position micron size particles, biological samples or even atoms with subnanometer accuracy in three dimensions. One limitation of optical tweezers is the weak force that can be applied without thermal damage due to optical absorption. Acoustical tweezers overcome this limitation since the radiation pressure scales as the field intensity divided by the speed of propagation of the wave. However, the feasibility of single beam acoustical tweezers was demonstrated only recently. In this paper, we propose a historical review of the strong similarities but also the specificities of acoustical and optical radiation pressures, from the expression of the force to the development of single-beam acoustical tweezers.

Broadband acoustic focusing by Airy-like beams based on acoustic metasurfaces

NASA Astrophysics Data System (ADS)

Chen, Di-Chao; Zhu, Xing-Feng; Wei, Qi; Wu, Da-Jian; Liu, Xiao-Jun

2018-01-01

An acoustic metasurface (AM) composed of space-coiling subunits is proposed to generate acoustic Airy-like beams (ALBs) by manipulating the transmitted acoustic phase. The self-accelerating, self-healing, and non-diffracting features of ALBs are demonstrated using finite element simulations. We further employ two symmetrical AMs to realize two symmetrical ALBs, resulting in highly efficient acoustic focusing. At the working frequency, the focal intensity can reach roughly 20 times that of the incident wave. It is found that the highly efficient acoustic focusing can circumvent obstacles in the propagating path and can be maintained in a broad frequency bandwidth. In addition, simply changing the separation between the two AMs can modulate the focal length of the proposed AM lens. ALBs generated by AMs and the corresponding AM lens may benefit applications in medical ultrasound imaging, biomedical therapy, and particle trapping and manipulation.

Comprehensive Characterization a Tidal Energy Site (Invited)

NASA Astrophysics Data System (ADS)

Polagye, B. L.; Thomson, J. M.; Bassett, C. S.; Epler, J.; Northwest National Marine Renewable Energy Center

2010-12-01

Northern Admiralty Inlet, Puget Sound, Washington is the proposed location of a pilot tidal energy project. Site-specific characterization of the physical and biological environment is required for device engineering and environmental analysis. However, the deep water and strong currents which make the site attractive for tidal energy development also pose unique challenges to collecting comprehensive information. This talk focuses on efforts to optimally site hydrokinetic turbines and estimate their acoustic impact, based on 18 months of field data collected to date. Additional characterization efforts being undertaken by the University of Washington branch of the Northwest National Marine Renewable Energy Center and its partners include marine mammal presence and behavior, water quality, seabed geology, and biofouling potential. Because kinetic power density varies with the cube of horizontal current velocity, an accurate map of spatial current variations is required to optimally site hydrokinetic turbines. Acoustic Doppler profilers deployed on the seabed show operationally meaningful variations in flow characteristics (e.g., power density, directionality, vertical shear) and tidal harmonic constituents over length scales of less than 100m. This is, in part, attributed to the proximity of this site to a headland. Because of these variations, interpolation between stationary measurement locations introduces potentially high uncertainty. The use of shipboard acoustic Doppler profilers is shown to be an effective tool for mapping peak currents and, combined with information from seabed profilers, may be able to resolve power density variations in the project area. Because noise levels from operating turbines are expected to exceed regulatory thresholds for incidental harassment of marine mammals known to be present in the project area, an estimate of the acoustic footprint is required to permit the pilot project. This requires site-specific descriptions of pre

Acoustic integrated extinction.

PubMed

Norris, Andrew N

2015-05-08

The integrated extinction (IE) is defined as the integral of the scattering cross section as a function of wavelength. Sohl et al. (2007 J. Acoust. Soc. Am. 122 , 3206-3210. (doi:10.1121/1.2801546)) derived an IE expression for acoustic scattering that is causal, i.e. the scattered wavefront in the forward direction arrives later than the incident plane wave in the background medium. The IE formula was based on electromagnetic results, for which scattering is causal by default. Here, we derive a formula for the acoustic IE that is valid for causal and non-causal scattering. The general result is expressed as an integral of the time-dependent forward scattering function. The IE reduces to a finite integral for scatterers with zero long-wavelength monopole and dipole amplitudes. Implications for acoustic cloaking are discussed and a new metric is proposed for broadband acoustic transparency.

Interacting Multiscale Acoustic Vortices as Coherent Excitations in Dust Acoustic Wave Turbulence

NASA Astrophysics Data System (ADS)

Lin, Po-Cheng; I, Lin

2018-03-01

In this work, using three-dimensional intermittent dust acoustic wave turbulence in a dusty plasma as a platform and multidimensional empirical mode decomposition into different-scale modes in the 2 +1 D spatiotemporal space, we demonstrate the experimental observation of the interacting multiscale acoustic vortices, winding around wormlike amplitude hole filaments coinciding with defect filaments, as the basic coherent excitations for acoustic-type wave turbulence. For different decomposed modes, the self-similar rescaled stretched exponential lifetime histograms of amplitude hole filaments, and the self-similar power spectra of dust density fluctuations, indicate that similar dynamical rules are followed over a wide range of scales. In addition to the intermode acoustic vortex pair generation, propagation, or annihilation, the intra- and intermode interactions of acoustic vortices with the same or opposite helicity, their entanglement and synchronization, are found to be the key dynamical processes in acoustic wave turbulence, akin to the interacting multiscale vortices around wormlike cores observed in hydrodynamic turbulence.

Acoustic Test Results of Melamine Foam with Application to Payload Fairing Acoustic Attenuation Systems

NASA Technical Reports Server (NTRS)

Hughes, William O.; McNelis, Anne M.

2014-01-01

A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle's payload fairing. In order to ensure the mission success of the spacecraft it is often necessary to reduce the resulting internal acoustic sound pressure levels through the usage of acoustic attenuation systems. Melamine foam, lining the interior walls of the payload fairing, is often utilized as the main component of such a system. In order to better understand the acoustic properties of melamine foam, with the goal of developing improved acoustic attenuation systems, NASA has recently performed panel level testing on numerous configurations of melamine foam acoustic treatments at the Riverbank Acoustical Laboratory. Parameters assessed included the foam's thickness and density, as well as the effects of a top outer cover sheet material and mass barriers embedded within the foam. This testing followed the ASTM C423 standard for absorption and the ASTM E90 standard for transmission loss. The acoustic test data obtained and subsequent conclusions are the subjects of this paper.

Acoustic Suppression Systems and Related Methods

NASA Technical Reports Server (NTRS)

Kolaini, Ali R. (Inventor); Kern, Dennis L. (Inventor)

2013-01-01

An acoustic suppression system for absorbing and/or scattering acoustic energy comprising a plurality of acoustic targets in a containment is described, the acoustic targets configured to have resonance frequencies allowing the targets to be excited by incoming acoustic waves, the resonance frequencies being adjustable to suppress acoustic energy in a set frequency range. Methods for fabricating and implementing the acoustic suppression system are also provided.

Introducing passive acoustic filter in acoustic based condition monitoring: Motor bike piston-bore fault identification

NASA Astrophysics Data System (ADS)

Jena, D. P.; Panigrahi, S. N.

2016-03-01

Requirement of designing a sophisticated digital band-pass filter in acoustic based condition monitoring has been eliminated by introducing a passive acoustic filter in the present work. So far, no one has attempted to explore the possibility of implementing passive acoustic filters in acoustic based condition monitoring as a pre-conditioner. In order to enhance the acoustic based condition monitoring, a passive acoustic band-pass filter has been designed and deployed. Towards achieving an efficient band-pass acoustic filter, a generalized design methodology has been proposed to design and optimize the desired acoustic filter using multiple filter components in series. An appropriate objective function has been identified for genetic algorithm (GA) based optimization technique with multiple design constraints. In addition, the sturdiness of the proposed method has been demonstrated in designing a band-pass filter by using an n-branch Quincke tube, a high pass filter and multiple Helmholtz resonators. The performance of the designed acoustic band-pass filter has been shown by investigating the piston-bore defect of a motor-bike using engine noise signature. On the introducing a passive acoustic filter in acoustic based condition monitoring reveals the enhancement in machine learning based fault identification practice significantly. This is also a first attempt of its own kind.

Cumulative impacts on seabed habitats: an indicator for assessments of good environmental status.

PubMed

Korpinen, Samuli; Meidinger, Manuel; Laamanen, Maria

2013-09-15

The European seas are under anthropogenic pressures impacting the state of water quality, benthic habitats and species. The EU Marine Strategy Framework Directive (MSFD) requires the Member States to assess the impacts of pressures and make a programme of measures leading to good environmental status (GES) by 2020. This study presents a method for assessing the quantity and distribution of anthropogenic impacts on benthic habitats in the Baltic Sea by using spatial data of human pressures and benthic habitats. The southern sub-basins were more extensively impacted than the northern sub-basins. Over the entire sea area, deep sea habitats were more impacted than shallower infralittoral and circalittoral habitats. Sand and coarse sediments were the seabed types relatively most impacted in the Baltic Sea scale. A comparison against tentative thresholds for GES showed that in the sub-basin scale only one third of the habitat types was in GES. Copyright © 2013 Elsevier Ltd. All rights reserved.

Surficial geology and benthic habitat of the German Bank seabed, Scotian Shelf, Canada

USGS Publications Warehouse

Todd, Brian J.; Kostylev, Vladimir E.

2011-01-01

To provide the scientific context for management of a newly opened scallop fishing ground, surficial geology and benthic habitats were mapped on German Bank on the southern Scotian Shelf off Atlantic Canada. To provide a seamless regional dataset, multibeam sonar surveys covered 5320 sqaure kilometres of the bank in water depths of 30–250 m and provided 5 m horizontal resolution bathymetry and backscatter strength. Geoscience data included high-resolution geophysical profiles (seismic reflection and sidescan sonar) and seabed sediment samples. Geological interpretation and is overlain in places by glacial and postglacial sediment. Biological data included seafloor video transects and photographs from which 127 taxa of visible megabenthos were identified. Trawl bycatch data were obtained from government annual research surveys. Statistical analysis of revealed that bedrock is exposed at the seafloor on much of German Bankthese two datasets and a suite of oceanographic environmental variables demonstrated that significantly different fauna exist on bedrock, glacial sediment and postglacial sediment.

Classification VIA Information-Theoretic Fusion of Vector-Magnetic and Acoustic Sensor Data

DTIC Science & Technology

2007-04-01

10) where tBsBtBsBtBsBtsB zzyyxx, . (11) The operation in (10) may be viewed as a vector matched- filter on to estimate )(tB CPARv . In summary...choosing to maximize the classification information in Y are described in Section 3.2. A 3.2. Maximum mutual information ( MMI ) features We begin with a...review of several desirable properties of features that maximize a mutual information ( MMI ) criterion. Then we review a particular algorithm [2

Mapping seabed geomorphology in the Inner Hebrides, Scotland; Bathymetric records of ice streaming and retreat

NASA Astrophysics Data System (ADS)

Dove, Dayton; Finlayson, Andrew; Bradwell, Tom; Arosio, Riccardo; Howe, John

2014-05-01

Approximately 7,000 km² of new bathymetry have been stitched together with onshore airborne radar data, both gridded at 5m resolution, to map and describe the submarine glacial landscape of the Inner Hebrides sector of the former British-Irish Ice Sheet (BIIS). As part of the MAREMAP Project (http://www.maremap.ac.uk), and to build on previous work (Howe et al., 2012), we are using recently acquired swath bathymetry data, collected primarily by the UKHO Civil Hydrography Programme, to characterise the geomorphology, sea-bed sediments, and bedrock geology of the Inner Hebrides region. Mapping has revealed an extensive array of well-preserved glacigenic landforms on the seabed associated with key stages of ice flow and retreat of the BIIS following the Last Glacial Maximum. On multiple submarine rock platforms and within overdeepened troughs, diverse assemblages of glacially streamlined landforms are present, forming a geomorphic continuum between rock drumlins and mega-flutes. Superimposed streamlined bedforms indicate different phases of fast flow at the ice sheet bed, and the convergence of flow sets suggest that ice sheet flow was organised into faster flowing topographically controlled corridors. Across the region, the streamlined landforms occur within a geographically controlled zone, semi-independent of the underlying geology. This is consistent with the onset zone of the Hebrides Ice Stream, as previously postulated (Howe et al., 2012). Submarine moraine ridges are observed widely across the survey area: within sea lochs, atop rock platforms and superimposed on glacially streamlined bedforms, as well as pinned to topographic highs (i.e. islands). Some retreat patterns reveal clear glacial recession towards respective catchments, while others are more ambiguous and are the focus of ongoing work. The bathymetry data notably reveal more geomorphic evidence of glaciation than adjacent land records, thus providing the opportunity to reassess onshore mapping

New Acoustic Arena Qualified at NASA Glenn's Aero-Acoustic Propulsion Laboratory

NASA Technical Reports Server (NTRS)

Wnuk, Stephen P.

2004-01-01

A new acoustic arena has been qualified in the Aero-Acoustic Propulsion Laboratory (AAPL) at the NASA Glenn Research Center. This arena is outfitted specifically for conducting fan noise research with the Advanced Noise Control Fan (ANCF) test rig. It features moveable walls with large acoustic wedges (2 by 2 by 1 ft) that create an acoustic environment usable at frequencies as low as 250 Hz. The arena currently uses two dedicated microphone arrays to acquire fan inlet and exhaust far-field acoustic data. It was used successfully in fiscal year 2003 to complete three ANCF tests. It also allowed Glenn to improve the operational efficiency of the four test rigs at AAPL and provided greater flexibility to schedule testing. There were a number of technical challenges to overcome in bringing the new arena to fruition. The foremost challenge was conflicting acoustic requirements of four different rigs. It was simply impossible to construct a static arena anywhere in the facility without intolerably compromising the acoustic test environment of at least one of the test rigs. This problem was overcome by making the wall sections of the new arena movable. Thus, the arena can be reconfigured to meet the operational requirements of any particular rig under test. Other design challenges that were encountered and overcome included structural loads of the large wedges, personnel access requirements, equipment maintenance requirements, and typical time and budget constraints. The new acoustic arena improves operations at the AAPL facility in several significant ways. First, it improves productivity by allowing multiple rigs to operate simultaneously. Second, it improves research data quality by providing a unique test area within the facility that is optimal for conducting fan noise research. Lastly, it reduces labor and equipment costs by eliminating the periodic need to transport the ANCF into and out of the primary AAPL acoustic arena. The investment to design, fabricate, and

Acoustic cooling engine

DOEpatents

Hofler, Thomas J.; Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

1988-01-01

An acoustic cooling engine with improved thermal performance and reduced internal losses comprises a compressible fluid contained in a resonant pressure vessel. The fluid has a substantial thermal expansion coefficient and is capable of supporting an acoustic standing wave. A thermodynamic element has first and second ends and is located in the resonant pressure vessel in thermal communication with the fluid. The thermal response of the thermodynamic element to the acoustic standing wave pumps heat from the second end to the first end. The thermodynamic element permits substantial flow of the fluid through the thermodynamic element. An acoustic driver cyclically drives the fluid with an acoustic standing wave. The driver is at a location of maximum acoustic impedance in the resonant pressure vessel and proximate the first end of the thermodynamic element. A hot heat exchanger is adjacent to and in thermal communication with the first end of the thermodynamic element. The hot heat exchanger conducts heat from the first end to portions of the resonant pressure vessel proximate the hot heat exchanger. The hot heat exchanger permits substantial flow of the fluid through the hot heat exchanger. The resonant pressure vessel can include a housing less than one quarter wavelength in length coupled to a reservoir. The housing can include a reduced diameter portion communicating with the reservoir. The frequency of the acoustic driver can be continuously controlled so as to maintain resonance.

Acoustic Translation of an Acoustically Levitated Sample

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Allen, J. L.

1986-01-01

Acoustic-levitation apparatus uses only one acoustic mode to move sample from one region of chamber to another. Sample heated and cooled quickly by translation between hot and cold regions of levitation chamber. Levitated sample is raised into furnace region by raising plunger. Frequency of sound produced by transducers adjusted by feedback system to maintain (102) resonant mode, which levitates sample midway between transducers and plunger regardless of plunger position.

Characterizing riverbed sediment using high-frequency acoustics 1: spectral properties of scattering

USGS Publications Warehouse

Buscombe, Daniel D.; Grams, Paul E.; Kaplinski, Matt A.

2014-01-01

Bed-sediment classification using high-frequency hydro-acoustic instruments is challenging when sediments are spatially heterogeneous, which is often the case in rivers. The use of acoustic backscatter to classify sediments is an attractive alternative to analysis of topography because it is potentially sensitive to grain-scale roughness. Here, a new method is presented which uses high-frequency acoustic backscatter from multibeam sonar to classify heterogeneous riverbed sediments by type (sand, gravel,rock) continuously in space and at small spatial resolution. In this, the first of a pair of papers that examine the scattering signatures from a heterogeneous riverbed, methods are presented to construct spatially explicit maps of spectral properties from geo-referenced point clouds of geometrically and radiometrically corrected echoes. Backscatter power spectra are computed to produce scale and amplitude metrics that collectively characterize the length scales of stochastic measures of riverbed scattering, termed ‘stochastic geometries’. Backscatter aggregated over small spatial scales have spectra that obey a power-law. This apparently self-affine behavior could instead arise from morphological- and grain-scale roughnesses over multiple overlapping scales, or riverbed scattering being transitional between Rayleigh and geometric regimes. Relationships exist between stochastic geometries of backscatter and areas of rough and smooth sediments. However, no one parameter can uniquely characterize a particular substrate, nor definitively separate the relative contributions of roughness and acoustic impedance (hardness). Combinations of spectral quantities do, however, have the potential to delineate riverbed sediment patchiness, in a data-driven approach comparing backscatter with bed-sediment observations (which is the subject of part two of this manuscript).

Contour mode resonators with acoustic reflectors

DOEpatents

Olsson, Roy H [Albuquerque, NM; Fleming, James G [Albuquerque, NM; Tuck, Melanie R [Albuquerque, NM

2008-06-10

A microelectromechanical (MEM) resonator is disclosed which has a linear or ring-shaped acoustic resonator suspended above a substrate by an acoustic reflector. The acoustic resonator can be formed with a piezoelectric material (e.g. aluminum nitride, zinc oxide or PZT), or using an electrostatically-actuated material. The acoustic reflector (also termed an acoustic mirror) uses alternating sections of a relatively low acoustic impedance Z.sub.L material and a relatively high acoustic impedance Z.sub.H material to isolate the acoustic resonator from the substrate. The MEM resonator, which can be formed on a silicon substrate with conventional CMOS circuitry, has applications for forming oscillators, rf filters, and acoustic sensors.

Towards marine seismological Network: real time small aperture seismic array

NASA Astrophysics Data System (ADS)

Ilinskiy, Dmitry

2017-04-01

Most powerful and dangerous seismic events are generated in underwater subduction zones. Existing seismological networks are based on land seismological stations. Increased demands for accuracy of location, magnitude, rupture process of coming earthquakes and at the same time reduction of data processing time require information from seabed seismic stations located near the earthquake generation area. Marine stations provide important contribution for clarification of the tectonic settings in most active subduction zones of the world. Early warning system for subduction zone area is based on marine seabed array which located near the area of most hazardous seismic zone in the region. Fast track processing for location of the earthquake hypocenter and energy takes place in buoy surface unit. Information about detected and located earthquake reaches the onshore seismological center earlier than the first break waves from the same earthquake will reach the nearest onshore seismological station. Implementation of small aperture array is based on existed and shown a good proven performance and costs effective solutions such as weather moored buoy and self-pop up autonomous seabed seismic nodes. Permanent seabed system for real-time operation has to be installed in deep sea waters far from the coast. Seabed array consists of several self-popup seismological stations which continuously acquire the data, detect the events of certain energy class and send detected event parameters to the surface buoy via acoustic link. Surface buoy unit determine the earthquake location by receiving the event parameters from seabed units and send such information in semi-real time to the onshore seismological center via narrow band satellite link. Upon the request from the cost the system could send wave form of events of certain energy class, bottom seismic station battery status and other environmental parameters. When the battery life of particular seabed unit is close to became empty

Acoustic Remote Sensing

NASA Astrophysics Data System (ADS)

Dowling, David R.; Sabra, Karim G.

2015-01-01

Acoustic waves carry information about their source and collect information about their environment as they propagate. This article reviews how these information-carrying and -collecting features of acoustic waves that travel through fluids can be exploited for remote sensing. In nearly all cases, modern acoustic remote sensing involves array-recorded sounds and array signal processing to recover multidimensional results. The application realm for acoustic remote sensing spans an impressive range of signal frequencies (10-2 to 107 Hz) and distances (10-2 to 107 m) and involves biomedical ultrasound imaging, nondestructive evaluation, oil and gas exploration, military systems, and Nuclear Test Ban Treaty monitoring. In the past two decades, approaches have been developed to robustly localize remote sources; remove noise and multipath distortion from recorded signals; and determine the acoustic characteristics of the environment through which the sound waves have traveled, even when the recorded sounds originate from uncooperative sources or are merely ambient noise.

The acoustic vector sensor: a versatile battlefield acoustics sensor

NASA Astrophysics Data System (ADS)

de Bree, Hans-Elias; Wind, Jelmer W.

2011-06-01

The invention of the Microflown sensor has made it possible to measure acoustic particle velocity directly. An acoustic vector sensor (AVS) measures the particle velocity in three directions (the source direction) and the pressure. The sensor is a uniquely versatile battlefield sensor because its size is a few millimeters and it is sensitive to sound from 10Hz to 10kHz. This article shows field tests results of acoustic vector sensors, measuring rifles, heavy artillery, fixed wing aircraft and helicopters. Experimental data shows that the sensor is suitable as a ground sensor, mounted on a vehicle and on a UAV.

Acoustic manipulation of oscillating spherical bodies: Emergence of axial negative acoustic radiation force

NASA Astrophysics Data System (ADS)

Rajabi, Majid; Mojahed, Alireza

2016-11-01

In this paper, emergence of negative axial acoustic radiation force on a rigid oscillating spherical body is investigated for acoustic manipulation purposes. The problem of plane acoustic wave scattering from an oscillating spherical body submerged in an ideal acoustic fluid medium is solved. For the case of oscillating direction collinear with the wave propagation wave number vector (desired path), it has been shown that the acoustic radiation force, as a result of nonlinear acoustic wave interaction with bodies can be expressed as a linear function of incident wave field and the oscillation properties of the oscillator (i.e., amplitude and phase of oscillation). The negative (i.e., pulling effects) and positive (i.e., pushing effects) radiation force situations are divided in oscillation complex plane with a specific frequency-dependant straight line. This characteristic line defines the radiation force cancellation state. In order to investigate the stability of the mentioned manipulation strategy, the case of misaligned oscillation of sphere with the wave propagation direction is studied. The proposed methodology may suggest a novel concept of single-beam acoustic handling techniques based on smart carriers.

Hybrid Electrostatic/Acoustic Levitator

NASA Technical Reports Server (NTRS)

Rhim, Won K.; Trinh, Eugene H.; Chung, Sang K.; Elleman, Daniel D.

1987-01-01

Because electrostatic and acoustic forces independent of each other, hybrid levitator especially suitable for studies of drop dynamics. Like all-acoustic or all-electrostatic systems, also used in studies of containerless material processing. Vertical levitating force applied to sample by upper and lower electrodes. Torques or vibrational forces in horizontal plane applied by acoustic transducers. Electrically charged water drop about 4 mm in diameter levitated electrostatically and rotated acoustically until it assumed dumbell shape and broke apart.

Education in acoustics in Argentina

NASA Astrophysics Data System (ADS)

Miyara, Federico

2002-11-01

Over the last decades, education in acoustics (EA) in Argentina has experienced ups and downs due to economic and political issues interfering with long term projects. Unlike other countries, like Chile, where EA has reached maturity in spite of the acoustical industry having shown little development, Argentina has several well-established manufacturers of acoustic materials and equipment but no specific career with a major in acoustics. At the university level, acoustics is taught as a complementary--often elective--course for careers such as architecture, communication engineering, or music. In spite of this there are several research centers with programs covering environmental and community noise, effects of noise on man, acoustic signal processing, musical acoustics and acoustic emission, and several national and international meetings are held each year in which results are communicated and discussed. Several books on a variety of topics such as sound system, architectural acoustics, and noise control have been published as well. Another chapter in EA is technical and vocational education, ranging between secondary and postsecondary levels, with technical training on sound system operation or design. Over the last years there have been several attempts to implement master degrees in acoustics or audio engineering, with little or no success.

The North Pacific Acoustic Laboratory deep-water acoustic propagation experiments in the Philippine Sea.

PubMed

Worcester, Peter F; Dzieciuch, Matthew A; Mercer, James A; Andrew, Rex K; Dushaw, Brian D; Baggeroer, Arthur B; Heaney, Kevin D; D'Spain, Gerald L; Colosi, John A; Stephen, Ralph A; Kemp, John N; Howe, Bruce M; Van Uffelen, Lora J; Wage, Kathleen E

2013-10-01

A series of experiments conducted in the Philippine Sea during 2009-2011 investigated deep-water acoustic propagation and ambient noise in this oceanographically and geologically complex region: (i) the 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) the 2010-2011 NPAL Philippine Sea Experiment, and (iii) the Ocean Bottom Seismometer Augmentation of the 2010-2011 NPAL Philippine Sea Experiment. The experimental goals included (a) understanding the impacts of fronts, eddies, and internal tides on acoustic propagation, (b) determining whether acoustic methods, together with other measurements and ocean modeling, can yield estimates of the time-evolving ocean state useful for making improved acoustic predictions, (c) improving our understanding of the physics of scattering by internal waves and spice, (d) characterizing the depth dependence and temporal variability of ambient noise, and (e) understanding the relationship between the acoustic field in the water column and the seismic field in the seafloor. In these experiments, moored and ship-suspended low-frequency acoustic sources transmitted to a newly developed distributed vertical line array receiver capable of spanning the water column in the deep ocean. The acoustic transmissions and ambient noise were also recorded by a towed hydrophone array, by acoustic Seagliders, and by ocean bottom seismometers.

Review of Progress in Acoustic Levitation

NASA Astrophysics Data System (ADS)

Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.

2018-04-01

Acoustic levitation uses acoustic radiation forces to counteract gravity and suspend objects in mid-air. Although acoustic levitation was first demonstrated almost a century ago, for a long time, it was limited to objects much smaller than the acoustic wavelength levitating at fixed positions in space. Recent advances in acoustic levitation now allow not only suspending but also rotating and translating objects in three dimensions. Acoustic levitation is also no longer restricted to small objects and can now be employed to levitate objects larger than the acoustic wavelength. This article reviews the progress of acoustic levitation, focusing on the working mechanism of different types of acoustic levitation devices developed to date. We start with a brief review of the theory. Then, we review the acoustic levitation methods to suspend objects at fixed positions, followed by the techniques that allow the manipulation of objects. Finally, we present a brief summary and offer some future perspectives for acoustic levitation.

Measuring acoustic habitats

PubMed Central

Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

2015-01-01

1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies. PMID:25954500

Measuring acoustic habitats.

PubMed

Merchant, Nathan D; Fristrup, Kurt M; Johnson, Mark P; Tyack, Peter L; Witt, Matthew J; Blondel, Philippe; Parks, Susan E

2015-03-01

1. Many organisms depend on sound for communication, predator/prey detection and navigation. The acoustic environment can therefore play an important role in ecosystem dynamics and evolution. A growing number of studies are documenting acoustic habitats and their influences on animal development, behaviour, physiology and spatial ecology, which has led to increasing demand for passive acoustic monitoring (PAM) expertise in the life sciences. However, as yet, there has been no synthesis of data processing methods for acoustic habitat monitoring, which presents an unnecessary obstacle to would-be PAM analysts. 2. Here, we review the signal processing techniques needed to produce calibrated measurements of terrestrial and aquatic acoustic habitats. We include a supplemental tutorial and template computer codes in matlab and r, which give detailed guidance on how to produce calibrated spectrograms and statistical analyses of sound levels. Key metrics and terminology for the characterisation of biotic, abiotic and anthropogenic sound are covered, and their application to relevant monitoring scenarios is illustrated through example data sets. To inform study design and hardware selection, we also include an up-to-date overview of terrestrial and aquatic PAM instruments. 3. Monitoring of acoustic habitats at large spatiotemporal scales is becoming possible through recent advances in PAM technology. This will enhance our understanding of the role of sound in the spatial ecology of acoustically sensitive species and inform spatial planning to mitigate the rising influence of anthropogenic noise in these ecosystems. As we demonstrate in this work, progress in these areas will depend upon the application of consistent and appropriate PAM methodologies.

Interaction of surface plasmon polaritons and acoustic waves inside an acoustic cavity.

PubMed

Khokhlov, Nikolai; Knyazev, Grigoriy; Glavin, Boris; Shtykov, Yakov; Romanov, Oleg; Belotelov, Vladimir

2017-09-15

In this Letter, we introduce an approach for manipulation of active plasmon polaritons via acoustic waves at sub-terahertz frequency range. The acoustic structures considered are designed as phononic Fabry-Perot microresonators where mirrors are presented with an acoustic superlattice and the structure's surface, and a plasmonic grating is placed on top of the acoustic cavity so formed. It provides phonon localization in the vicinity of the plasmonic grating at frequencies within the phononic stop band enhancing phonon-light interaction. We consider phonon excitation by shining a femtosecond laser pulse on the plasmonic grating. Appropriate theoretical model was used to describe the acoustic process caused by the pump laser pulse in the GaAs/AlAs-based acoustic cavity with a gold grating on top. Strongest modulation is achieved upon excitation of propagating surface plasmon polaritons and hybridization of propagating and localized plasmons. The relative changes in the optical reflectivity of the structure are more than an order of magnitude higher than for the structure without the plasmonic film.

Acoustic biosensors.

PubMed

Fogel, Ronen; Limson, Janice; Seshia, Ashwin A

2016-06-30

Resonant and acoustic wave devices have been researched for several decades for application in the gravimetric sensing of a variety of biological and chemical analytes. These devices operate by coupling the measurand (e.g. analyte adsorption) as a modulation in the physical properties of the acoustic wave (e.g. resonant frequency, acoustic velocity, dissipation) that can then be correlated with the amount of adsorbed analyte. These devices can also be miniaturized with advantages in terms of cost, size and scalability, as well as potential additional features including integration with microfluidics and electronics, scaled sensitivities associated with smaller dimensions and higher operational frequencies, the ability to multiplex detection across arrays of hundreds of devices embedded in a single chip, increased throughput and the ability to interrogate a wider range of modes including within the same device. Additionally, device fabrication is often compatible with semiconductor volume batch manufacturing techniques enabling cost scalability and a high degree of precision and reproducibility in the manufacturing process. Integration with microfluidics handling also enables suitable sample pre-processing/separation/purification/amplification steps that could improve selectivity and the overall signal-to-noise ratio. Three device types are reviewed here: (i) bulk acoustic wave sensors, (ii) surface acoustic wave sensors, and (iii) micro/nano-electromechanical system (MEMS/NEMS) sensors. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

High temperature acoustic and hybrid microwave/acoustic levitators for materials processing

NASA Technical Reports Server (NTRS)

Barmatz, Martin

1990-01-01

The physical acoustics group at the Jet Propulsion Laboratory developed a single mode acoustic levitator technique for advanced containerless materials processing. The technique was successfully demonstrated in ground based studies to temperatures of about 1000 C in a uniform temperature furnace environment and to temperatures of about 1500 C using laser beams to locally heat the sample. Researchers are evaluating microwaves as a more efficient means than lasers for locally heating a positioned sample. Recent tests of a prototype single mode hybrid microwave/acoustic levitator successfully demonstrated the feasibility of using microwave power as a heating source. The potential advantages of combining acoustic positioning forces and microwave heating for containerless processing investigations are presented in outline form.

Acoustic emission frequency discrimination

NASA Technical Reports Server (NTRS)

Sugg, Frank E. (Inventor); Graham, Lloyd J. (Inventor)

1988-01-01

In acoustic emission nondestructive testing, broadband frequency noise is distinguished from narrow banded acoustic emission signals, since the latter are valid events indicative of structural flaws in the material being examined. This is accomplished by separating out those signals which contain frequency components both within and beyond (either above or below) the range of valid acoustic emission events. Application to acoustic emission monitoring during nondestructive bond verification and proof loading of undensified tiles on the Space Shuttle Orbiter is considered.

Research on Acoustical Scattering, Diffraction Catastrophes, Optics of Bubbles, Photoacoustics, and Acoustical Phase Conjugation.

DTIC Science & Technology

1987-09-15

optical levitation of bubbles; D. Acoustical and optical diffraction catastrophes (theory and optical simulation of transverse cusps, experiments with...35 C. Optical Levitation of Bubbles in Water by the Radiation Pressure of a Laser Beam: An Acoustically Quiet Levitator ...radiation pressure of a laser beam: an acoustically quiet levitator ," J. Acoust . Soc. Am. (submitted July 1987). C. Books (and sections thereof) Published

Acoustics

NASA Technical Reports Server (NTRS)

Goodman, Jerry R.; Grosveld, Ferdinand

2007-01-01

The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources

USGS Publications Warehouse

Williams, S.J.; Bliss, J.D.; Arsenault, M.A.; Jenkins, C.J.; Goff, J.A.

2007-01-01

Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

Cave acoustics in prehistory: Exploring the association of Palaeolithic visual motifs and acoustic response.

PubMed

Fazenda, Bruno; Scarre, Chris; Till, Rupert; Pasalodos, Raquel Jiménez; Guerra, Manuel Rojo; Tejedor, Cristina; Peredo, Roberto Ontañón; Watson, Aaron; Wyatt, Simon; Benito, Carlos García; Drinkall, Helen; Foulds, Frederick

2017-09-01

During the 1980 s, acoustic studies of Upper Palaeolithic imagery in French caves-using the technology then available-suggested a relationship between acoustic response and the location of visual motifs. This paper presents an investigation, using modern acoustic measurement techniques, into such relationships within the caves of La Garma, Las Chimeneas, La Pasiega, El Castillo, and Tito Bustillo in Northern Spain. It addresses methodological issues concerning acoustic measurement at enclosed archaeological sites and outlines a general framework for extraction of acoustic features that may be used to support archaeological hypotheses. The analysis explores possible associations between the position of visual motifs (which may be up to 40 000 yrs old) and localized acoustic responses. Results suggest that motifs, in general, and lines and dots, in particular, are statistically more likely to be found in places where reverberation is moderate and where the low frequency acoustic response has evidence of resonant behavior. The work presented suggests that an association of the location of Palaeolithic motifs with acoustic features is a statistically weak but tenable hypothesis, and that an appreciation of sound could have influenced behavior among Palaeolithic societies of this region.

Implementation and performance evaluation of acoustic denoising algorithms for UAV

NASA Astrophysics Data System (ADS)

Chowdhury, Ahmed Sony Kamal

Unmanned Aerial Vehicles (UAVs) have become popular alternative for wildlife monitoring and border surveillance applications. Elimination of the UAV's background noise and classifying the target audio signal effectively are still a major challenge. The main goal of this thesis is to remove UAV's background noise by means of acoustic denoising techniques. Existing denoising algorithms, such as Adaptive Least Mean Square (LMS), Wavelet Denoising, Time-Frequency Block Thresholding, and Wiener Filter, were implemented and their performance evaluated. The denoising algorithms were evaluated for average Signal to Noise Ratio (SNR), Segmental SNR (SSNR), Log Likelihood Ratio (LLR), and Log Spectral Distance (LSD) metrics. To evaluate the effectiveness of the denoising algorithms on classification of target audio, we implemented Support Vector Machine (SVM) and Naive Bayes classification algorithms. Simulation results demonstrate that LMS and Discrete Wavelet Transform (DWT) denoising algorithm offered superior performance than other algorithms. Finally, we implemented the LMS and DWT algorithms on a DSP board for hardware evaluation. Experimental results showed that LMS algorithm's performance is robust compared to DWT for various noise types to classify target audio signals.

An Expendable Source for Measuring Shallow Water Acoustic Propagation and Geo-Acoustic Bottom Properties

DTIC Science & Technology

2015-09-30

Propagation and Geo -Acoustic Bottom Properties Harry A DeFerrari RSMAS – University of Miami 4600 Rickenbacker Causeway Miami FL. 33149...limited information about the ocean acoustic environment and the geo -acoustic properties of the bottom. The objective here is to measure the pulse...models and estimate the geo -acoustic properties of the bottom by inversion. APPROACH M-sequences have long been the workhorse of basic research

Observation of self-excited acoustic vortices in defect-mediated dust acoustic wave turbulence.

PubMed

Tsai, Ya-Yi; I, Lin

2014-07-01

Using the self-excited dust acoustic wave as a platform, we demonstrate experimental observation of self-excited fluctuating acoustic vortex pairs with ± 1 topological charges through spontaneous waveform undulation in defect-mediated turbulence for three-dimensional traveling nonlinear longitudinal waves. The acoustic vortex pair has helical waveforms with opposite chirality around the low-density hole filament pair in xyt space (the xy plane is the plane normal to the wave propagation direction). It is generated through ruptures of sequential crest surfaces and reconnections with their trailing ruptured crest surfaces. The initial rupture is originated from the amplitude reduction induced by the formation of the kinked wave crest strip with strong stretching through the undulation instability. Increasing rupture causes the separation of the acoustic vortex pair after generation. A similar reverse process is followed for the acoustic vortex annihilating with the opposite-charged acoustic vortex from the same or another pair generation.

Ares I Scale Model Acoustic Test Lift-Off Acoustics

NASA Technical Reports Server (NTRS)

Counter, Douglas D.; Houston, Janie D.

2011-01-01

The lift-off acoustic (LOA) environment is an important design factor for any launch vehicle. For the Ares I vehicle, the LOA environments were derived by scaling flight data from other launch vehicles. The Ares I LOA predicted environments are compared to the Ares I Scale Model Acoustic Test (ASMAT) preliminary results.

Acoustic Response of Underwater Munitions near a Sediment Interface: Measurement Model Comparisons and Classification Schemes

DTIC Science & Technology

2015-04-23

12 Figure 4. Pulse- compressed baseband signals for sequence 40 from TREX13 …… 13 Figure 5. SAS image for sequence 40 from TREX13...12 meshes with data …………… 28 Figure 14. FE simulations for aluminum and steel replicas of an 100-mm UXO …… 28 Figure 15. FE meshes for two targets...PCB Pulse- compressed and baseband PC SWAT Personal Computer Shallow Water Acoustic Toolset PondEx09 Pond Experiment 2009 PondEx10 Pond Experiment

Object Classification in Semi Structured Enviroment Using Forward-Looking Sonar

PubMed Central

dos Santos, Matheus; Ribeiro, Pedro Otávio; Núñez, Pedro; Botelho, Silvia

2017-01-01

The submarine exploration using robots has been increasing in recent years. The automation of tasks such as monitoring, inspection, and underwater maintenance requires the understanding of the robot’s environment. The object recognition in the scene is becoming a critical issue for these systems. On this work, an underwater object classification pipeline applied in acoustic images acquired by Forward-Looking Sonar (FLS) are studied. The object segmentation combines thresholding, connected pixels searching and peak of intensity analyzing techniques. The object descriptor extract intensity and geometric features of the detected objects. A comparison between the Support Vector Machine, K-Nearest Neighbors, and Random Trees classifiers are presented. An open-source tool was developed to annotate and classify the objects and evaluate their classification performance. The proposed method efficiently segments and classifies the structures in the scene using a real dataset acquired by an underwater vehicle in a harbor area. Experimental results demonstrate the robustness and accuracy of the method described in this paper. PMID:28961163

Acoustic Neuroma Association

MedlinePlus

... Gold Sponsor NSPC Brain & Spine Surgery Learn More Gold Sponsor University of Colorado Acoustic Neuroma Program and Rocky Mountain Gamma Knife Center Learn More Gold Sponsor USC Acoustic Neuroma Center Learn More Gold ...

Carbon Nanotube Underwater Acoustic Thermophone

DTIC Science & Technology

2016-09-23

Attorney Docket No. 300009 1 of 8 A CARBON NANOTUBE UNDERWATER ACOUSTIC THERMOPHONE STATEMENT OF GOVERNMENT INTEREST [0001] The...the Invention [0003] The present invention is an acoustically transparent carbon nanotube thermophone. (2) Description of the Prior Art [0004...Traditional acoustic transduction typically begins with the generation of electrical excitation pulsed through an amplifier into an electro- acoustic

Acoustic building infiltration measurement system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muehleisen, Ralph T.; Raman, Ganesh

Systems and methods of detecting and identifying a leak from a container or building. Acoustic pressure and velocity are measured. Acoustic properties are acquired from the measured values. The acoustic properties are converted to infiltration/leakage information. Nearfield Acoustic Holography (NAH) may be one method to detect the leakages from a container by locating the noise sources.

The accidental (acoustical) tourist

NASA Astrophysics Data System (ADS)

Van Kirk, Wayne

2002-11-01

The acoustical phenomenon observed at an ancient temple in the Great Ball Court at Chichen Itza was described as ''little short of amazing--an ancient whispering gallery'' by Silvanus G. Morley, leader of the Carnegie Institute's archaeological team that excavated and restored these structures in the 1920s. Since then, many others have experienced the extraordinary acoustics at Chichen Itza and other Maya sites. Despite these reports, archaeologists and acousticians have until recently shown little interest in understanding these phenomena. After experiencing Chichen Itza's remarkable acoustics as a tourist in 1994, the author commenced collecting and disseminating information about acoustical phenomena there and at other Mayan sites, hoping to stimulate interest among archaeologists and acousticians. Were these designs accidental or intentional? If intentional, how was the knowledge obtained? How were acoustical features used? This paper highlights the author's collection of anecdotal reports of mysterious Mayan acoustics (http://http://www.ianlawton.com/pa1.htm<\\/A>), recommended reading for scientists and engineers who wish to pursue this fascinating study. Also recounted are some of the reactions of archaeologists-ranging from curious, helpful, and insightful to humorous and appalling--to outsiders' efforts to bring serious scientific attention to the new field of acoustical archaeology.

Signal classification using global dynamical models, Part II: SONAR data analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kremliovsky, M.; Kadtke, J.

1996-06-01

In Part I of this paper, we described a numerical method for nonlinear signal detection and classification which made use of techniques borrowed from dynamical systems theory. Here in Part II of the paper, we will describe an example of data analysis using this method, for data consisting of open ocean acoustic (SONAR) recordings of marine mammal transients, supplied from NUWC sources. The purpose here is two-fold: first to give a more operational description of the technique and provide rules-of-thumb for parameter choices; and second to discuss some new issues raised by the analysis of non-ideal (real-world) data sets. Themore » particular data set considered here is quite non-stationary, relatively noisy, is not clearly localized in the background, and as such provides a difficult challenge for most detection/classification schemes. {copyright} {ital 1996 American Institute of Physics.}« less

Developments in Acoustic Metamaterials for Acoustic Ground Cloaks

NASA Astrophysics Data System (ADS)

Kerrian, Peter Adam

The objective of acoustic cloaking is to eliminate both the back scattered and forward scattered acoustic fields by redirecting the incident wave around an object. Acoustic ground cloaks, which conceal an object on a rigid reflecting surface, utilize a linear coordinate transformation to map the flat surface to a void by compressing space into two cloaking regions consisting of a homogeneous anisotropic acoustic metafluid. Transformation acoustics allows for the realization of a coordinate transformation through a reinterpretation of the scale factors as a new material in the original coordinate system. Previous work has demonstrated at least three types of unit cells exhibit homogeneous anisotropic mass density and homogeneous isotropic bulk modulus: alternating layers of homogeneous isotropic fluids, perforated plates and solid inclusions. The primary focus of this dissertation is to demonstrate underwater anisotropic mass density with a solid inclusion unit cell and realize an underwater perforated plate acoustic ground cloak. An in depth analysis into the methods used to characterize the effective material parameters of solid inclusion unit cells with water as the background fluid was performed for both single inclusion unit cells as well as multi-inclusion unit cells. The degree of density anisotropy obtainable for a rigid single inclusion unit cell is limited by the size of the inclusion. However, a greater degree of anisotropy can be achieved by introducing additional inclusions into the unit cell design. For example, including a foam material that is less dense than the background fluid, results in an anisotropic density tensor with one component greater than and one component less than the value of the background fluid. The results of a parametric study determined that for a multi-inclusion unit cell, the effective material parameters can be controlled by the dimensions of the rigid inclusion as well as the material parameters and dimensions of the foam

Diagnosing Acoustic Neuroma

MedlinePlus

... Other symptoms of the acoustic neuroma include asymmetric tinnitus (ringing in the ear), dizziness and disequilibrium (difficulty ... than 80% of patients having acoustic neuromas have tinnitus. Tinnitus is usually described as hissing, ringing, buzzing ...

Acoustic field modulation in regenerators

NASA Astrophysics Data System (ADS)

Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

2016-12-01

The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

Ares I Scale Model Acoustic Tests Instrumentation for Acoustic and Pressure Measurements

NASA Technical Reports Server (NTRS)

Vargas, Magda B.; Counter, Douglas D.

2011-01-01

The Ares I Scale Model Acoustic Test (ASMAT) was a development test performed at the Marshall Space Flight Center (MSFC) East Test Area (ETA) Test Stand 116. The test article included a 5% scale Ares I vehicle model and tower mounted on the Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments located throughout the test article. There were four primary ASMAT instrument suites: ignition overpressure (IOP), lift-off acoustics (LOA), ground acoustics (GA), and spatial correlation (SC). Each instrumentation suite incorporated different sensor models which were selected based upon measurement requirements. These requirements included the type of measurement, exposure to the environment, instrumentation check-outs and data acquisition. The sensors were attached to the test article using different mounts and brackets dependent upon the location of the sensor. This presentation addresses the observed effect of the sensors and mounts on the acoustic and pressure measurements.

Acoustics of a planetarium

NASA Astrophysics Data System (ADS)

Shepherd, Micah; Leishman, Timothy W.; Utami, Sentagi

2005-09-01

Brigham Young University has recently constructed a planetarium with a 38-ft.-diameter dome. The facility also serves as a classroom. Since planetariums typically have poor acoustics due to their domed ceiling structures, acoustical recommendations were requested before its construction. The recommendations were made in an attempt to create an acceptable listening environment for lectures and other listening events. They were based in part on computer models and auralizations intended to predict the effectiveness of several acoustical treatments on the outer walls and on the dome itself. The recommendations were accepted and the planetarium was completed accordingly. A series of acoustical measurements was subsequently made in the room and the resulting acoustical parameters were mapped over the floor plan. This paper discusses these results and compares them with the predictions of the computer models.

Investigation into the Effect of Acoustic Radiation Force and Acoustic Streaming on Particle Patterning in Acoustic Standing Wave Fields

PubMed Central

Yang, Yanye; Ni, Zhengyang; Guo, Xiasheng; Luo, Linjiao; Tu, Juan; Zhang, Dong

2017-01-01

Acoustic standing waves have been widely used in trapping, patterning, and manipulating particles, whereas one barrier remains: the lack of understanding of force conditions on particles which mainly include acoustic radiation force (ARF) and acoustic streaming (AS). In this paper, force conditions on micrometer size polystyrene microspheres in acoustic standing wave fields were investigated. The COMSOL® Mutiphysics particle tracing module was used to numerically simulate force conditions on various particles as a function of time. The velocity of particle movement was experimentally measured using particle imaging velocimetry (PIV). Through experimental and numerical simulation, the functions of ARF and AS in trapping and patterning were analyzed. It is shown that ARF is dominant in trapping and patterning large particles while the impact of AS increases rapidly with decreasing particle size. The combination of using both ARF and AS for medium size particles can obtain different patterns with only using ARF. Findings of the present study will aid the design of acoustic-driven microfluidic devices to increase the diversity of particle patterning. PMID:28753955

Modeling interface roughness scattering in a layered seabed for normal-incident chirp sonar signals.

PubMed

Tang, Dajun; Hefner, Brian T

2012-04-01

Downward looking sonar, such as the chirp sonar, is widely used as a sediment survey tool in shallow water environments. Inversion of geo-acoustic parameters from such sonar data precedes the availability of forward models. An exact numerical model is developed to initiate the simulation of the acoustic field produced by such a sonar in the presence of multiple rough interfaces. The sediment layers are assumed to be fluid layers with non-intercepting rough interfaces.

Ocean acoustic reverberation tomography.

PubMed

Dunn, Robert A

2015-12-01

Seismic wide-angle imaging using ship-towed acoustic sources and networks of ocean bottom seismographs is a common technique for exploring earth structure beneath the oceans. In these studies, the recorded data are dominated by acoustic waves propagating as reverberations in the water column. For surveys with a small receiver spacing (e.g., <10 km), the acoustic wave field densely samples properties of the water column over the width of the receiver array. A method, referred to as ocean acoustic reverberation tomography, is developed that uses the travel times of direct and reflected waves to image ocean acoustic structure. Reverberation tomography offers an alternative approach for determining the structure of the oceans and advancing the understanding of ocean heat content and mixing processes. The technique has the potential for revealing small-scale ocean thermal structure over the entire vertical height of the water column and along long survey profiles or across three-dimensional volumes of the ocean. For realistic experimental geometries and data noise levels, the method can produce images of ocean sound speed on a smaller scale than traditional acoustic tomography.

Acoustic well cleaner

DOEpatents

Maki, Jr., Voldi E.; Sharma, Mukul M.

1997-01-21

A method and apparatus are disclosed for cleaning the wellbore and the near wellbore region. A sonde is provided which is adapted to be lowered into a borehole and which includes a plurality of acoustic transducers arranged around the sonde. Electrical power provided by a cable is converted to acoustic energy. The high intensity acoustic energy directed to the borehole wall and into the near wellbore region, redissolves or resuspends the material which is reducing the permeability of the formation and/or restricting flow in the wellbore.

Characterizing Broadband Acoustic Propagation Scintillation and Modelling Scattering and Reverberation for Sensing in a Random Ocean Waveguide

DTIC Science & Technology

2014-09-30

34Ecosystem scale acoustic sensing reveals humpback whale behavior synchronous with herring spawning processes and re-evaluation finds no effect of sonar...on humpback song occurrence in the Gulf of Maine in Fall 2006." PlosOne (accepted, in print for 2014). 2. D. Tran, W. Huang, A. Bohn, D. Wang, Z...Gong, N. Makris and P. Ratilal, "Using a coherent hydrophone array for observing sperm whale range, classification, and shallow-water dive profiles

Vowel Acoustic Space Development in Children: A Synthesis of Acoustic and Anatomic Data

ERIC Educational Resources Information Center

Vorperian, Houri K.; Kent, Ray D.

2007-01-01

Purpose: This article integrates published acoustic data on the development of vowel production. Age specific data on formant frequencies are considered in the light of information on the development of the vocal tract (VT) to create an anatomic-acoustic description of the maturation of the vowel acoustic space for English. Method: Literature…

3D AUV Microseismic Implementation for Deepwater Seabed Investigations

NASA Astrophysics Data System (ADS)

George, R.; Taylor, M. W.; Gravely, J. G.

2005-05-01

Autonomous Underwater Vehicle (AUV) technology, developed commercially over the past 5 years, allows for the geophysical investigation of the seabed on the deepwater continental slope at resolutions, data densities and timelines not previously attainable. High-resolution geophysical systems normally employed on deepwater survey AUVs consist of multibeam bathymetry, side scan sonar and subbottom profiler. Inertial navigation allows positioning accuracies on the order of plus or minus 3 meters in depths up to 2,000 meters. C & C Technologies, Inc. owns and operates the C-Surveyor I AUV, which has collected more than 40,000 km of geohazard survey data on the continental slopes of the Gulf of Mexico, Mediterranean Sea, Brazil and West Africa. The oil and gas industry routinely engineers deepwater platform-mooring systems and other bottom founded subsea systems for exploration and production developments. Resolute subbottom imaging of the foundation zone in order to identify the near-seafloor geologic conditions at these deepwater development sites is critical in order to maintain system integrity. The paper describes the methodology and post-processing techniques used to create a high-resolution (2-8 kHz) 3D seismic cube from subbottom profiler data collected from an AUV system. Data examples of the multibeam bathymetry, side scan sonar and 2D seismic profiles will be provided to complement the results of the 3D seismic cube processing. Examples of inlines, crosslines, arbitrary lines, seafloor amplitude extraction and time slices are presented for the 4-meter binned data set. Advantages, disadvantages and suggested improvements for the survey acquisition technique and post processing are discussed.

Acoustic Levitation With Less Equipment

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Jacobi, N.

1983-01-01

Certain chamber shapes require fewer than three acoustic drivers. Levitation at center of spherical chamber attained using only one acoustic driver. Exitation of lowest spherical mode produces asymmetric acoustic potential well.

Laser acoustic emission thermal technique (LAETT): a technique for generating acoustic emission in dental composites.

PubMed

Duray, S J; Lee, S Y; Menis, D L; Gilbert, J L; Lautenschlager, E P; Greener, E H

1996-01-01

This study was designed to investigate a new method for generating interfacial debonding between the resin matrix and filler particles of dental composites. A pilot study was conducted to evaluate laser-induced acoustic emission in dental resins filled with varying quantities of particles. Model systems of 50/50 BisGMA/TEGDMA resin reinforced with 0, 25, and 75 wt% 5-10 micrometers silanated BaSiO(6) were analyzed. The sample size was 3.5 mm diameter x 0.25-0.28 mm thick. A continuous wave CO2 laser (Synrad Infrared Gas Laser Model 48-1) was used to heat the composite samples. Acoustic events were detected, recorded and processed by a model 4610 Smart Acoustic Monitor (SAM) with a 1220A preamp (Physical Acoustic Corp.) as a function of laser power. Initially, the acoustic signal from the model composites produced a burst pattern characteristic of fracturing, about 3.7 watts laser power. Acoustic emission increased with laser power up to about 6 watts. At laser powers above 6 watts, the acoustic emission remained constant. The amount of acoustic emission followed the trend: unfilled resin > composite with 25 wt% BaSiO(6) > composite with 75 wt% BaSiO(6). Acoustic emission generated by laser thermal heating is dependent on the weight percent of filler particles in the composite and the amount of laser power. For this reason, laser thermal acoustic emission might be useful as a nondestructive form of analysis of dental composites.

Turbofan Acoustic Propagation and Radiation

NASA Technical Reports Server (NTRS)

Eversman, Walter

2000-01-01

This document describes progress in the development of finite element codes for the prediction of near and far field acoustic radiation from the inlet and aft fan ducts of turbofan engines. The report consists of nine papers which have appeared in archival journals and conference proceedings, or are presently in review for publication. Topics included are: 1. Aft Fan Duct Acoustic Radiation; 2. Mapped Infinite Wave Envelope Elements for Acoustic Radiation in a Uniformly Moving Medium; 3. A Reflection Free Boundary Condition for Propagation in Uniform Flow Using Mapped Infinite Wave Envelope Elements; 4. A Numerical Comparison Between Multiple-Scales and FEM Solution for Sound Propagation in Lined Flow Ducts; 5. Acoustic Propagation at High Frequencies in Ducts; 6. The Boundary Condition at an Impedance Wall in a Nonuniform Duct with Potential Flow; 7. A Reverse Flow Theorem and Acoustic Reciprocity in Compressible Potential Flows; 8. Reciprocity and Acoustics Power in One Dimensional Compressible Potential Flows; and 9. Numerical Experiments on Acoustic Reciprocity in Compressible Potential Flows.

Variable-Position Acoustic Levitation

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Stoneburner, J. D.; Jacobi, N.; Wang, T. G.

1983-01-01

Method of acoustic levitation supports objects at positions other than acoustic nodes. Acoustic force is varied so it balances gravitational (or other) force, thereby maintaining object at any position within equilibrium range. Levitation method applicable to containerless processing. Such objects as table-tennis balls, hollow plastic spheres, and balsa-wood spheres levitated in laboratory by new method.

Waves propagating over a two-layer porous barrier on a seabed

NASA Astrophysics Data System (ADS)

Lin, Qiang; Meng, Qing-rui; Lu, Dong-qiang

2018-05-01

A research of wave propagation over a two-layer porous barrier, each layer of which is with different values of porosity and friction, is conducted with a theoretical model in the frame of linear potential flow theory. The model is more appropriate when the seabed consists of two different properties, such as rocks and breakwaters. It is assumed that the fluid is inviscid and incompressible and the motion is irrotational. The wave numbers in the porous region are complex ones, which are related to the decaying and propagating behaviors of wave modes. With the aid of the eigenfunction expansions, a new inner product of the eigenfunctions in the two-layer porous region is proposed to simplify the calculation. The eigenfunctions, under this new definition, possess the orthogonality from which the expansion coefficients can be easily deduced. Selecting the optimum truncation of the series, we derive a closed system of simultaneous linear equations for the same number of the unknown reflection and transmission coefficients. The effects of several physical parameters, including the porosity, friction, width, and depth of the porous barrier, on the dispersion relation, reflection and transmission coefficients are discussed in detail through the graphical representations of the solutions. It is concluded that these parameters have certain impacts on the reflection and transmission energy.

Photo-acoustic and video-acoustic methods for sensing distant sound sources

NASA Astrophysics Data System (ADS)

Slater, Dan; Kozacik, Stephen; Kelmelis, Eric

2017-05-01

Long range telescopic video imagery of distant terrestrial scenes, aircraft, rockets and other aerospace vehicles can be a powerful observational tool. But what about the associated acoustic activity? A new technology, Remote Acoustic Sensing (RAS), may provide a method to remotely listen to the acoustic activity near these distant objects. Local acoustic activity sometimes weakly modulates the ambient illumination in a way that can be remotely sensed. RAS is a new type of microphone that separates an acoustic transducer into two spatially separated components: 1) a naturally formed in situ acousto-optic modulator (AOM) located within the distant scene and 2) a remote sensing readout device that recovers the distant audio. These two elements are passively coupled over long distances at the speed of light by naturally occurring ambient light energy or other electromagnetic fields. Stereophonic, multichannel and acoustic beam forming are all possible using RAS techniques and when combined with high-definition video imagery it can help to provide a more cinema like immersive viewing experience. A practical implementation of a remote acousto-optic readout device can be a challenging engineering problem. The acoustic influence on the optical signal is generally weak and often with a strong bias term. The optical signal is further degraded by atmospheric seeing turbulence. In this paper, we consider two fundamentally different optical readout approaches: 1) a low pixel count photodiode based RAS photoreceiver and 2) audio extraction directly from a video stream. Most of our RAS experiments to date have used the first method for reasons of performance and simplicity. But there are potential advantages to extracting audio directly from a video stream. These advantages include the straight forward ability to work with multiple AOMs (useful for acoustic beam forming), simpler optical configurations, and a potential ability to use certain preexisting video recordings. However

Particle filtering based structural assessment with acoustic emission sensing

NASA Astrophysics Data System (ADS)

Yan, Wuzhao; Abdelrahman, Marwa; Zhang, Bin; Ziehl, Paul

2017-02-01

Nuclear structures are designed to withstand severe loading events under various stresses. Over time, aging of structural systems constructed with concrete and steel will occur. This deterioration may reduce service life of nuclear facilities and/or lead to unnecessary or untimely repairs. Therefore, online monitoring of structures in nuclear power plants and waste storage has drawn significant attention in recent years. Of many existing non-destructive evaluation and structural monitoring approaches, acoustic emission is promising for assessment of structural damage because it is non-intrusive and is sensitive to corrosion and crack growth in reinforced concrete elements. To provide a rapid, actionable, and graphical means for interpretation Intensity Analysis plots have been developed. This approach provides a means for classification of damage. Since the acoustic emission measurement is only an indirect indicator of structural damage, potentially corrupted by non-genuine data, it is more suitable to estimate the states of corrosion and cracking in a Bayesian estimation framework. In this paper, we will utilize the accelerated corrosion data from a specimen at the University of South Carolina to develop a particle filtering-based diagnosis and prognosis algorithm. Promising features of the proposed algorithm are described in terms of corrosion state estimation and prediction of degradation over time to a predefined threshold.

Constraints on the Dynamics of Seabed Pockmarks: an Integrated Sedimentological, Biostratigraphic, Geophysical, Oceanographic and Experimental Approach

NASA Astrophysics Data System (ADS)

Pau, M.; Hammer, Ø.; Chand, S.; Gisler, G. R.

2015-12-01

Pockmarks are crater-like seabed depressions commonly resulting from focused fluid escape from soft, fine-grained sediments. Typically measuring 20-50 m across with depths of 2-10 m, these features often occur in extensive fields containing hundreds of them per square kilometre. They are prominent hazards for offshore installations such as oil rigs and pipelines, affecting vast areas worldwide. Besides, they represent a major geological source of methane, and their importance has been pointed out as contributors to the global climate variability.Sedimentological and biostratigraphic analyses of sediment cores were coupled with shallow seismic images to investigate the origin and evolution of a pockmark field in the southwestern Barents Sea, an epicontinental sea part of the Arctic Ocean. The pockmarks formed as a result of reduced sedimentation above active gas seeps near the retreating edge of the Barents Sea ice sheet about 15,000 years ago. The seepage is ascribed to climate change-induced dissociation of methane hydrates. These findings strengthen the case that pockmarks, worldwide, recorded the release of massive quantities of methane from the seafloor into the ocean during the last deglaciation. No evidence was found for current upward methane flux, so the pockmarks in the study area appear as inactive seabed features. Field measurements of currents and sediment fluxes in pockmarks in the Oslofjord, Norway, along with an experimental hydrodynamics study, provide insight into the mechanisms responsible for the long-term maintenance of inactive pockmarks. Near-bed currents may control the net sedimentation rate in these depressions by inhibiting the sedimentation from suspended transport. Enhanced turbulence and more intense biological activity suggest that the suspended fines are supported in the water column more easily in the pockmarks than on the surrounding bed, and can be transported away before settling. Moreover, upwelling generated by flow deflection

Low frequency acoustic microscope

DOEpatents

Khuri-Yakub, Butrus T.

1986-11-04

A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

The Nozzle Acoustic Test Rig: an Acoustic and Aerodynamic Free-jet Facility

NASA Technical Reports Server (NTRS)

Castner, Raymond S.

1994-01-01

The nozzle acoustic test rig (NATR) was built at NASA Lewis Research Center to support the High Speed Research Program. The facility is capable of measuring the acoustic and aerodynamic performance of aircraft engine nozzle concepts. Trade-off studies are conducted to compare performance and noise during simulated low-speed flight and takeoff. Located inside an acoustically treated dome with a 62-ft radius, the NATR is a free-jet that has a 53-in. diameter and is driven by an air ejector. This ejector is operated with 125 lb/s of compressed air, at 125 psig, to achieve 375 lb/s at Mach 0.3. Acoustic and aerodynamic data are collected from test nozzles mounted in the free-jet flow. The dome serves to protect the surrounding community from high noise levels generated by the nozzles, and to provide an anechoic environment for acoustic measurements. Information presented in this report summarizes free-jet performance, fluid support systems, and data acquisition capabilities of the NATR.

Magnetoactive Acoustic Metamaterials.

PubMed

Yu, Kunhao; Fang, Nicholas X; Huang, Guoliang; Wang, Qiming

2018-04-11

Acoustic metamaterials with negative constitutive parameters (modulus and/or mass density) have shown great potential in diverse applications ranging from sonic cloaking, abnormal refraction and superlensing, to noise canceling. In conventional acoustic metamaterials, the negative constitutive parameters are engineered via tailored structures with fixed geometries; therefore, the relationships between constitutive parameters and acoustic frequencies are typically fixed to form a 2D phase space once the structures are fabricated. Here, by means of a model system of magnetoactive lattice structures, stimuli-responsive acoustic metamaterials are demonstrated to be able to extend the 2D phase space to 3D through rapidly and repeatedly switching signs of constitutive parameters with remote magnetic fields. It is shown for the first time that effective modulus can be reversibly switched between positive and negative within controlled frequency regimes through lattice buckling modulated by theoretically predicted magnetic fields. The magnetically triggered negative-modulus and cavity-induced negative density are integrated to achieve flexible switching between single-negative and double-negative. This strategy opens promising avenues for remote, rapid, and reversible modulation of acoustic transportation, refraction, imaging, and focusing in subwavelength regimes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spacecraft Internal Acoustic Environment Modeling

NASA Technical Reports Server (NTRS)

Allen, Christopher; Chu, S. Reynold

2008-01-01

The objective of the project is to develop an acoustic modeling capability, based on commercial off-the-shelf software, to be used as a tool for oversight of the future manned Constellation vehicles to ensure compliance with acoustic requirements and thus provide a safe and habitable acoustic environment for the crews, and to validate developed models via building physical mockups and conducting acoustic measurements.

Saturn systems holddown acoustic efficiency and normalized acoustic power spectrum.

NASA Technical Reports Server (NTRS)

Gilbert, D. W.

1972-01-01

Saturn systems field acoustic data are used to derive mid- and far-field prediction parameters for rocket engine noise. The data were obtained during Saturn vehicle launches at the Kennedy Space Center. The data base is a sorted set of acoustic data measured during the period 1961 through 1971 for Saturn system launches SA-1 through AS-509. The model assumes hemispherical radiation from a simple source located at the intersection of the longitudinal axis of each booster and the engine exit plane. The model parameters are evaluated only during vehicle holddown. The acoustic normalized power spectrum and efficiency for each system are isolated as a composite from the data using linear numerical methods. The specific definitions of each allows separation. The resulting power spectra are nondimensionalized as a function of rocket engine parameters. The nondimensional Saturn system acoustic spectrum and efficiencies are compared as a function of Strouhal number with power spectra from other systems.

Applications of surface acoustic and shallow bulk acoustic wave devices

NASA Astrophysics Data System (ADS)

Campbell, Colin K.

1989-10-01

Surface acoustic wave (SAW) device coverage includes delay lines and filters operating at selected frequencies in the range from about 10 MHz to 11 GHz; modeling with single-crystal piezoelectrics and layered structures; resonators and low-loss filters; comb filters and multiplexers; antenna duplexers; harmonic devices; chirp filters for pulse compression; coding with fixed and programmable transversal filters; Barker and quadraphase coding; adaptive filters; acoustic and acoustoelectric convolvers and correlators for radar, spread spectrum, and packet radio; acoustooptic processors for Bragg modulation and spectrum analysis; real-time Fourier-transform and cepstrum processors for radar and sonar; compressive receivers; Nyquist filters for microwave digital radio; clock-recovery filters for fiber communications; fixed-, tunable-, and multimode oscillators and frequency synthesizers; acoustic charge transport; and other SAW devices for signal processing on gallium arsenide. Shallow bulk acoustic wave device applications include gigahertz delay lines, surface-transverse-wave resonators employing energy-trapping gratings, and oscillators with enhanced performance and capability.

Compact acoustic refrigerator

DOEpatents

Bennett, G.A.

1992-11-24

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits, in a borehole environment. An acoustic engine includes first thermodynamic elements for generating a standing acoustic wave in a selected medium. An acoustic refrigerator includes second thermodynamic elements located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements and a relatively hot temperature at a second end of the second thermodynamic elements. A resonator volume cooperates with the first and second thermodynamic elements to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements, first heat pipes transfer heat from the heat load to the second thermodynamic elements and second heat pipes transfer heat from first and second thermodynamic elements to the borehole environment. 18 figs.

Acoustic imaging system

DOEpatents

Smith, Richard W.

1979-01-01

An acoustic imaging system for displaying an object viewed by a moving array of transducers as the array is pivoted about a fixed point within a given plane. A plurality of transducers are fixedly positioned and equally spaced within a laterally extending array and operatively directed to transmit and receive acoustic signals along substantially parallel transmission paths. The transducers are sequentially activated along the array to transmit and receive acoustic signals according to a preestablished sequence. Means are provided for generating output voltages for each reception of an acoustic signal, corresponding to the coordinate position of the object viewed as the array is pivoted. Receptions from each of the transducers are presented on the same display at coordinates corresponding to the actual position of the object viewed to form a plane view of the object scanned.

Transmission acoustic microscopy investigation

NASA Astrophysics Data System (ADS)

Maev, Roman; Kolosov, Oleg; Levin, Vadim; Lobkis, Oleg

The nature of acoustic contrast, i.e. the connection of the amplitude and phase of the output signal of the acoustic microscope with the local values of the acoustic parameters of the sample (density, elasticity, viscosity) is a central problem of acoustic microscopy. A considerable number of studies have been devoted to the formation of the output signal of the reflection scanning acoustic microscope. For the transmission acoustic microscope (TAM) this problem has remained almost unstudied. Experimental investigation of the confocal system of the TAM was carried out on an independently manufactured laboratory mockup of the TAM with the working frequency of the 420 MHz. Acoustic lenses with the radius of curvature of about 500 microns and aperture angle of 45 deg were polished out in the end faces of two cylindrical sound conductors made from Al2O3 single crystals with an axis parallel to the axis C of the crystal (the length of the sound conductor is 20 mm; diameter, 6 mm). At the end faces of the sound conductor, opposite to the lenses, CdS transducers with a diameter of 2 mm were disposed. The electric channel of the TAM provided a possibility for registering the amplitude of the microscope output signal in the case of the dynamic range of the 50 dB.

What Is an Acoustic Neuroma

MedlinePlus

... CALENDAR DONATE NEWS Home Learn Back Learn about acoustic neuroma AN Facts What is acoustic neuroma? Diagnosing ... Italian Japanese Korean Portuguese Romanian Spanish What is Acoustic Neuroma? Each heading slides to reveal information. Important ...

Tutorial on architectural acoustics

NASA Astrophysics Data System (ADS)

Shaw, Neil; Talaske, Rick; Bistafa, Sylvio

2002-11-01

This tutorial is intended to provide an overview of current knowledge and practice in architectural acoustics. Topics covered will include basic concepts and history, acoustics of small rooms (small rooms for speech such as classrooms and meeting rooms, music studios, small critical listening spaces such as home theatres) and the acoustics of large rooms (larger assembly halls, auditoria, and performance halls).

Hurricane Sandy's Fingerprint: Ripple Bedforms at an Inner Continental Shelf Sorted Bedform Field Site

NASA Astrophysics Data System (ADS)

DuVal, C.; Trembanis, A. C.; Beaudoin, J. D.; Schmidt, V. E.; Mayer, L. A.

2013-12-01

The hydrodynamics and seabed morphodynamics on the inner continental shelf and near shore environments have increasing relevance with continued development of near shore structures, offshore energy technologies and artificial reef construction. Characterizing the stresses on and response of the seabed near and around seabed objects will inform best practices for structural design, seabed mine and unexploded ordnance detection, and archaeological and benthic habitat studies. As part of an ONR funded project, Delaware's Redbird Reef is being studied for object scour and sorted bedform morphodynamics (Trembanis et al., in press). Central to this study are the effects of large storm events, such as Hurricane Sandy, which have had significant impact on the seafloor. Previous studies of inner shelf bedform dynamics have typically focused on near bed currents and bed stressors (e.g. Trembanis et al., 2004), sorted bedforms (e.g. Green et al., 2004) and object scour (e.g. Quinn, 2006; Trembanis et al., 2007; Mayer et al., 2007), but our understanding of the direct effects of objects and object scour on bedform morphodynamics is still incomplete. With prominent sorted bedform ripple fields, the Delaware Redbird artificial reef site, composed of 997 former New York City subway cars, as well as various military vehicles, tugboats, barges and ballasted tires, has made an ideal study location (Raineault et al., 2013 and 2011). Acoustic mapping of the Redbird reef three days prior to Sandy and two days after the following nor'easter, captured the extensive effects of the storms to the site, while acoustic Doppler current profilers characterized both the waves and bottom currents generated by the storm events. Results of the post-Sandy survey support the theory of sorted bedform evolution proposed by Murray and Thieler (2004). Acoustic imagery analysis indicates a highly energized and mobile bed during the storms, leading to self-organization of bedforms and creation of large

Seabed roughness parameters from joint backscatter and reflection inversion at the Malta Plateau.

PubMed

Steininger, Gavin; Holland, Charles W; Dosso, Stan E; Dettmer, Jan

2013-09-01

This paper presents estimates of seabed roughness and geoacoustic parameters and uncertainties on the Malta Plateau, Mediterranean Sea, by joint Bayesian inversion of mono-static backscatter and spherical wave reflection-coefficient data. The data are modeled using homogeneous fluid sediment layers overlying an elastic basement. The scattering model assumes a randomly rough water-sediment interface with a von Karman roughness power spectrum. Scattering and reflection data are inverted simultaneously using a population of interacting Markov chains to sample roughness and geoacoustic parameters as well as residual error parameters. Trans-dimensional sampling is applied to treat the number of sediment layers and the order (zeroth or first) of an autoregressive error model (to represent potential residual correlation) as unknowns. Results are considered in terms of marginal posterior probability profiles and distributions, which quantify the effective data information content to resolve scattering/geoacoustic structure. Results indicate well-defined scattering (roughness) parameters in good agreement with existing measurements, and a multi-layer sediment profile over a high-speed (elastic) basement, consistent with independent knowledge of sand layers over limestone.

A Cross-Language Study of Acoustic Predictors of Speech Intelligibility in Individuals With Parkinson's Disease

PubMed Central

Choi, Yaelin

2017-01-01

Purpose The present study aimed to compare acoustic models of speech intelligibility in individuals with the same disease (Parkinson's disease [PD]) and presumably similar underlying neuropathologies but with different native languages (American English [AE] and Korean). Method A total of 48 speakers from the 4 speaker groups (AE speakers with PD, Korean speakers with PD, healthy English speakers, and healthy Korean speakers) were asked to read a paragraph in their native languages. Four acoustic variables were analyzed: acoustic vowel space, voice onset time contrast scores, normalized pairwise variability index, and articulation rate. Speech intelligibility scores were obtained from scaled estimates of sentences extracted from the paragraph. Results The findings indicated that the multiple regression models of speech intelligibility were different in Korean and AE, even with the same set of predictor variables and with speakers matched on speech intelligibility across languages. Analysis of the descriptive data for the acoustic variables showed the expected compression of the vowel space in speakers with PD in both languages, lower normalized pairwise variability index scores in Korean compared with AE, and no differences within or across language in articulation rate. Conclusions The results indicate that the basis of an intelligibility deficit in dysarthria is likely to depend on the native language of the speaker and listener. Additional research is required to explore other potential predictor variables, as well as additional language comparisons to pursue cross-linguistic considerations in classification and diagnosis of dysarthria types. PMID:28821018

Properties of Materials Using Acoustic Waves.

DTIC Science & Technology

1982-05-01

Acoust. Soc. Am. 69, 1624 (1981). R.E. Apfel, "Acoustic Cavitation : A Possible Consequence of Biomedical Uses of Ultrasound ," Brit. J. Cancer, in...efforts can be classified into four broad categories; - Applications of acoustic levitation; nonlinear acoustics and radiation pressure; acoustic cavitation ...supercooled water - a question of concern to cryobiologists. We have also measured the properties of several lipid oils (only available in less than

Pathological speech signal analysis and classification using empirical mode decomposition.

PubMed

Kaleem, Muhammad; Ghoraani, Behnaz; Guergachi, Aziz; Krishnan, Sridhar

2013-07-01

Automated classification of normal and pathological speech signals can provide an objective and accurate mechanism for pathological speech diagnosis, and is an active area of research. A large part of this research is based on analysis of acoustic measures extracted from sustained vowels. However, sustained vowels do not reflect real-world attributes of voice as effectively as continuous speech, which can take into account important attributes of speech such as rapid voice onset and termination, changes in voice frequency and amplitude, and sudden discontinuities in speech. This paper presents a methodology based on empirical mode decomposition (EMD) for classification of continuous normal and pathological speech signals obtained from a well-known database. EMD is used to decompose randomly chosen portions of speech signals into intrinsic mode functions, which are then analyzed to extract meaningful temporal and spectral features, including true instantaneous features which can capture discriminative information in signals hidden at local time-scales. A total of six features are extracted, and a linear classifier is used with the feature vector to classify continuous speech portions obtained from a database consisting of 51 normal and 161 pathological speakers. A classification accuracy of 95.7 % is obtained, thus demonstrating the effectiveness of the methodology.

Micromachined silicon acoustic delay line with improved structural stability and acoustic directivity for real-time photoacoustic tomography

NASA Astrophysics Data System (ADS)

Cho, Young; Kumar, Akhil; Xu, Song; Zou, Jun

2017-03-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. However, as its length increases to provide longer delay time, the delay line becomes more vulnerable to structural instability due to reduced mechanical stiffness. In addition, the small cross-section area of the delay line results in a large acoustic acceptance angle and therefore poor directivity. To address these two issues, this paper reports the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, a new tapered design for the input terminal of the delay line was also investigate to improve its acoustic directivity by reducing the acoustic acceptance angle. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

Acoustic Imaging of a Turbidity Current Flowing along a Channel

NASA Astrophysics Data System (ADS)

Hughes Clarke, J. E.; Hiroji, A.; Cahill, L.; Fedele, J. J.

2017-12-01

As part of a 3 month sequence of repetitive surveys and ADCP monitoring, more than 30 turbidity currents have been identified modifying a lobe channel in 130 to 190m of water on the Squamish prodelta. For a 6 day period, daily surveys at low tide tried to capture the change resulting from a single flow. On the 8thof June three flows occurred within a half hour. Along channel multibeam images of the seabed and water column were obtained from a moving vessel immediately before, during and after the passage of the third flow. In this manner the spatial extent of the in-channel and overbank flow could be constrained. By following the flow, the spatial pattern of scattering from the flow upper surface could be examined over a 2 km length of the channel. Along channel bands of high scattering appear related to enhanced release of gas along the channel flanks. Notably, no signature of the underlying across-channel bedform modulations were evident, suggesting that the upper surface of the flow does not feel the influence of the channel floor. Overbank spillage of the flow could be detected by perturbation of a plankton scattering layer just above the seabed. Additionally, evidence of enhanced overbank deposition due to flow stripping on the outer corner of a bend was identified from backscatter changes. The specific seabed alteration due to this flow could be identified and compared with the cumulative change over three months in the channel and adjacent channel-lobe transition zone. As the flow passed under the ADCP, it had a peak velocity of over 2 m/s, a thickness of 4-5m and duration of 35 minutes. Based on the timing of the flow head when in view of the surface vessel, it was decelerating as it exited the mouth of the channel.

Multimode Acoustic Research

NASA Technical Reports Server (NTRS)

Barmatz, M.

1985-01-01

There is a need for high temperature containerless processing facilities that can efficiently position and manipulate molten samples in the reduced gravity environment of space. The goal of the research is to develop sophisticated high temperature manipulation capabilities such as selection of arbitrary axes rotation and rapid sample cooling. This program will investigate new classes of acoustic levitation in rectangular, cylindrical and spherical geometries. The program tasks include calculating theoretical expressions of the acoustic forces in these geometries for the excitation of up to three acoustic modes (multimodes). These calculations are used to: (1) determine those acoustic modes that produce stable levitation, (2) isolate the levitation and rotation capabilities to produce more than one axis of rotation, and (3) develop methods to translate samples down long tube cylindrical chambers. Experimental levitators will then be constructed to verify the stable levitation and rotation predictions of the models.

A generalized baleen whale call detection and classification system.

PubMed

Baumgartner, Mark F; Mussoline, Sarah E

2011-05-01

Passive acoustic monitoring allows the assessment of marine mammal occurrence and distribution at greater temporal and spatial scales than is now possible with traditional visual surveys. However, the large volume of acoustic data and the lengthy and laborious task of manually analyzing these data have hindered broad application of this technique. To overcome these limitations, a generalized automated detection and classification system (DCS) was developed to efficiently and accurately identify low-frequency baleen whale calls. The DCS (1) accounts for persistent narrowband and transient broadband noise, (2) characterizes temporal variation of dominant call frequencies via pitch-tracking, and (3) classifies calls based on attributes of the resulting pitch tracks using quadratic discriminant function analysis (QDFA). Automated detections of sei whale (Balaenoptera borealis) downsweep calls and North Atlantic right whale (Eubalaena glacialis) upcalls were evaluated using recordings collected in the southwestern Gulf of Maine during the spring seasons of 2006 and 2007. The accuracy of the DCS was similar to that of a human analyst: variability in differences between the DCS and an analyst was similar to that between independent analysts, and temporal variability in call rates was similar among the DCS and several analysts.

The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

NASA Technical Reports Server (NTRS)

Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

2011-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC s Plum Brook Station in Sandusky, Ohio. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

The Development of the Acoustic Design of NASA Glenn Research Center's New Reverberant Acoustic Test Facility

NASA Technical Reports Server (NTRS)

Hughes, William O.; McNelis, Mark E.; Hozman, Aron D.; McNelis, Anne M.

2011-01-01

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is leading the design and build of the new world-class vibroacoustic test capabilities at the NASA GRC's Plum Brook Station in Sandusky, Ohio, USA. Benham Companies, LLC is currently constructing modal, base-shake sine and reverberant acoustic test facilities to support the future testing needs of NASA s space exploration program. The large Reverberant Acoustic Test Facility (RATF) will be approximately 101,000 ft3 in volume and capable of achieving an empty chamber acoustic overall sound pressure level (OASPL) of 163 dB. This combination of size and acoustic power is unprecedented amongst the world s known active reverberant acoustic test facilities. The key to achieving the expected acoustic test spectra for a range of many NASA space flight environments in the RATF is the knowledge gained from a series of ground acoustic tests. Data was obtained from several NASA-sponsored test programs, including testing performed at the National Research Council of Canada s acoustic test facility in Ottawa, Ontario, Canada, and at the Redstone Technical Test Center acoustic test facility in Huntsville, Alabama, USA. The majority of these tests were performed to characterize the acoustic performance of the modulators (noise generators) and representative horns that would be required to meet the desired spectra, as well as to evaluate possible supplemental gas jet noise sources. The knowledge obtained in each of these test programs enabled the design of the RATF sound generation system to confidently advance to its final acoustic design and subsequent on-going construction.

Acoustic Levitator Maintains Resonance

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Gaspar, M. S.

1986-01-01

Transducer loading characteristics allow resonance tracked at high temperature. Acoustic-levitation chamber length automatically adjusted to maintain resonance at constant acoustic frequency as temperature changes. Developed for containerless processing of materials at high temperatures, system does not rely on microphones as resonance sensors, since microphones are difficult to fabricate for use at temperatures above 500 degrees C. Instead, system uses acoustic transducer itself as sensor.

Back-and-Forth Methodology for Objective Voice Quality Assessment: From/to Expert Knowledge to/from Automatic Classification of Dysphonia

NASA Astrophysics Data System (ADS)

Fredouille, Corinne; Pouchoulin, Gilles; Ghio, Alain; Revis, Joana; Bonastre, Jean-François; Giovanni, Antoine

2009-12-01

This paper addresses voice disorder assessment. It proposes an original back-and-forth methodology involving an automatic classification system as well as knowledge of the human experts (machine learning experts, phoneticians, and pathologists). The goal of this methodology is to bring a better understanding of acoustic phenomena related to dysphonia. The automatic system was validated on a dysphonic corpus (80 female voices), rated according to the GRBAS perceptual scale by an expert jury. Firstly, focused on the frequency domain, the classification system showed the interest of 0-3000 Hz frequency band for the classification task based on the GRBAS scale. Later, an automatic phonemic analysis underlined the significance of consonants and more surprisingly of unvoiced consonants for the same classification task. Submitted to the human experts, these observations led to a manual analysis of unvoiced plosives, which highlighted a lengthening of VOT according to the dysphonia severity validated by a preliminary statistical analysis.

Time-reversal imaging for classification of submerged elastic targets via Gibbs sampling and the Relevance Vector Machine.

PubMed

Dasgupta, Nilanjan; Carin, Lawrence

2005-04-01

Time-reversal imaging (TRI) is analogous to matched-field processing, although TRI is typically very wideband and is appropriate for subsequent target classification (in addition to localization). Time-reversal techniques, as applied to acoustic target classification, are highly sensitive to channel mismatch. Hence, it is crucial to estimate the channel parameters before time-reversal imaging is performed. The channel-parameter statistics are estimated here by applying a geoacoustic inversion technique based on Gibbs sampling. The maximum a posteriori (MAP) estimate of the channel parameters are then used to perform time-reversal imaging. Time-reversal implementation requires a fast forward model, implemented here by a normal-mode framework. In addition to imaging, extraction of features from the time-reversed images is explored, with these applied to subsequent target classification. The classification of time-reversed signatures is performed by the relevance vector machine (RVM). The efficacy of the technique is analyzed on simulated in-channel data generated by a free-field finite element method (FEM) code, in conjunction with a channel propagation model, wherein the final classification performance is demonstrated to be relatively insensitive to the associated channel parameters. The underlying theory of Gibbs sampling and TRI are presented along with the feature extraction and target classification via the RVM.

Acoustic Resonance Spectroscopy (ARS) Munition Classification System enhancements. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vela, O.A.; Huggard, J.C.

Acoustic Resonance Spectroscopy (ARS) is a non-destructive evaluation technology developed at the Los Alamos National Laboratory (LANL). This technology has resulted in three generations of instrumentation, funded by the Defense Special Weapons Agency (DSWA), specifically designed for field identification of chemical weapon (CW) munitions. Each generation of ARS instrumentation was developed with a specific user in mind. The ARS1OO was built for use by the U.N. Inspection Teams going into Iraq immediately after the Persian Gulf War. The ARS200 was built for use in the US-Russia Bilateral Chemical Weapons Treaty (the primary users for this system are the US Onsitemore » Inspection Agency (OSIA) and their Russian counterparts). The ARS300 was built with the requirements of the Organization for the Prohibition of Chemical Weapons (OPCW) in mind. Each successive system is an improved version of the previous system based on learning the weaknesses of each and, coincidentally, on the fact that more time was available to do a requirements analysis and the necessary engineering development. The ARS300 is at a level of development that warrants transferring the technology to a commercial vendor. Since LANL will supply the computer software to the selected vendor, it is possible for LANL to continue to improve the decision algorithms, add features where necessary, and adjust the user interface before the final transfer occurs. This paper describes the current system, ARS system enhancements, and software enhancements. Appendices contain the Operations Manual (software Version 3.01), and two earlier reports on enhancements.« less

Acoustic and microwave tests in a cylindrical cavity for acoustic gas thermometry at high temperature

PubMed Central

Zhang, K.; Feng, X.J.; Gillis, K.; Moldover, M.; Zhang, J.T.; Lin, H.; Qu, J.F.; Duan, Y.N.

2016-01-01

Relative primary acoustic gas thermometry determines the ratios of thermodynamic temperatures from measured ratios of acoustic and microwave resonance frequencies in a gas-filled metal cavity on isotherms of interest. When measured in a cavity with known dimensions, the frequencies of acoustic resonances in a gas determine the speed of sound, which is a known function of the thermodynamic temperature T. Changes in the dimensions of the cavity are measured using the frequencies of the cavity's microwave resonances. We explored techniques and materials for acoustic gas thermometry at high temperatures using a cylindrical cavity with remote acoustic transducers. We used gas-filled ducts as acoustic waveguides to transmit sound between the cavity at high temperatures and the acoustic transducers at room temperature. We measured non-degenerate acoustic modes in a cylindrical cavity in the range 295 K < T < 797 K. The fractional uncertainty of the measured acoustic frequencies increased from 2×10−6 at 295 K to 5×10−6 at 797 K. In addition, we measured the frequencies of several transverse magnetic (TM) microwave resonances up to 1000 K in order to track changes in the cavity's length L and radius R. The fractional standard deviation of the values of L deduced from three TM modes increased from 3×10−6 for T < 600 K to 57×10−6 at 1000 K. We observed similar inconsistencies in a previous study. PMID:26903106

Airy acoustical-sheet spinner tweezers

NASA Astrophysics Data System (ADS)

Mitri, F. G.

2016-09-01

The Airy acoustical beam exhibits parabolic propagation and spatial acceleration, meaning that the propagation bending angle continuously increases before the beam trajectory reaches a critical angle where it decays after a propagation distance, without applying any external bending force. As such, it is of particular importance to investigate its properties from the standpoint of acoustical radiation force, spin torque, and particle dynamics theories, in the development of novel particle sorting techniques and acoustically mediated clearing systems. This work investigates these effects on a two-dimensional (2D) circular absorptive structure placed in the field of a nonparaxial Airy "acoustical-sheet" (i.e., finite beam in 2D), for potential applications in surface acoustic waves and acousto-fluidics. Based on the characteristics of the acoustic field, the beam is capable of manipulating the circular cylindrical fluid cross-section and guides it along a transverse or parabolic trajectory. This feature of Airy acoustical beams could lead to a unique characteristic in single-beam acoustical tweezers related to acoustical sieving, filtering, and removal of particles and cells from a section of a small channel. The analysis developed here is based on the description of the nonparaxial Airy beam using the angular spectrum decomposition of plane waves in close association with the partial-wave series expansion method in cylindrical coordinates. The numerical results demonstrate the ability of the nonparaxial Airy acoustical-sheet beam to pull, propel, or accelerate a particle along a parabolic trajectory, in addition to particle confinement in the transverse direction of wave propagation. Negative or positive radiation force and spin torque causing rotation in the clockwise or the anticlockwise direction can occur depending on the nondimensional parameter ka (where k is the wavenumber and a is the radius) and the location of the cylinder in the beam. Applications in

Direct Field Acoustic Testing

NASA Technical Reports Server (NTRS)

Larkin, Paul; Goldstein, Bob

2008-01-01

This paper presents an update to the methods and procedures used in Direct Field Acoustic Testing (DFAT). The paper will discuss some of the recent techniques and developments that are currently being used and the future publication of a reference standard. Acoustic testing using commercial sound system components is becoming a popular and cost effective way of generating a required acoustic test environment both in and out of a reverberant chamber. This paper will present the DFAT test method, the usual setup and procedure and the development and use of a closed-loop, narrow-band control system. Narrow-band control of the acoustic PSD allows all standard techniques and procedures currently used in random control to be applied to acoustics and some examples are given. The paper will conclude with a summary of the development of a standard practice guideline that is hoped to be available in the first quarter of next year.

Wideband acoustic microscopy of tissue.

PubMed

Daft, C W; Briggs, G D

1989-01-01

A scanning acoustic microscope (SAM) has been used to measure the elastic properties of tissue with a resolution of around 8 mum. This is achieved by broadband excitation of the acoustic lens, and the recording of an undemodulated returning signal. A method of analyzing this information to yield sound velocity, acoustic impedance, section thickness, and acoustic attenuation is described. Results from a sample of skin tissue are presented and compared with data from a computer simulation of the experiment.

Verification of Ares I Liftoff Acoustic Environments via the Ares I Scale Model Acoustic Test

NASA Technical Reports Server (NTRS)

Counter, Douglas; Houston, Janice

2012-01-01

The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the predicted Ares I liftoff acoustic environments and to determine the acoustic reduction gained by using an above deck water sound suppression system. The test article included a 5% scale Ares I vehicle model and Mobile Launcher with tower. Acoustic and pressure data were measured by over 200 instruments. The ASMAT results are compared to Ares I-X flight data.

Wideband acoustic wave resonators composed of hetero acoustic layer structure

NASA Astrophysics Data System (ADS)

Kadota, Michio; Tanaka, Shuji

2018-07-01

“Hetero acoustic layer (HAL) surface acoustic wave (SAW) device” is a new type of SAW device using a single crystal piezoelectric thin plate supported by a substrate. In this study, a HAL SAW resonator using a LiNbO3 (LN) thin plate and a multi-layer acoustic film was designed by finite element method (FEM) and fabricated. The thickness of LN is 3.6 µm and the pitch of an interdigital transducer (IDT) (λ) is 5.24 µm for a resonance frequency of 600 MHz. The multi-layer acoustic film is composed of 3 layers of SiO2 and AlN for each, i.e., 6 layers in total, alternately deposited on a glass substrate. The HAL SAW resonator achieved a wide bandwidth of 20.3% and a high impedance ratio of 83 dB. Compared with a 0th shear horizontal (SH0) mode plate wave resonator, the performance is better and the thickness of LN is 7 times larger. The HAL SAW without a cavity is advantageous in terms of mechanical stability, thickness controllability and fabrication yield.

Acoustic Absorption in Porous Materials

NASA Technical Reports Server (NTRS)

Kuczmarski, Maria A.; Johnston, James C.

2011-01-01

An understanding of both the areas of materials science and acoustics is necessary to successfully develop materials for acoustic absorption applications. This paper presents the basic knowledge and approaches for determining the acoustic performance of porous materials in a manner that will help materials researchers new to this area gain the understanding and skills necessary to make meaningful contributions to this field of study. Beginning with the basics and making as few assumptions as possible, this paper reviews relevant topics in the acoustic performance of porous materials, which are often used to make acoustic bulk absorbers, moving from the physics of sound wave interactions with porous materials to measurement techniques for flow resistivity, characteristic impedance, and wavenumber.

Department of Cybernetic Acoustics

NASA Astrophysics Data System (ADS)

The development of the theory, instrumentation and applications of methods and systems for the measurement, analysis, processing and synthesis of acoustic signals within the audio frequency range, particularly of the speech signal and the vibro-acoustic signal emitted by technical and industrial equipments treated as noise and vibration sources was discussed. The research work, both theoretical and experimental, aims at applications in various branches of science, and medicine, such as: acoustical diagnostics and phoniatric rehabilitation of pathological and postoperative states of the speech organ; bilateral ""man-machine'' speech communication based on the analysis, recognition and synthesis of the speech signal; vibro-acoustical diagnostics and continuous monitoring of the state of machines, technical equipments and technological processes.

Compact acoustic refrigerator

DOEpatents

Bennett, Gloria A.

1992-01-01

A compact acoustic refrigeration system actively cools components, e.g., electrical circuits (22), in a borehole environment. An acoustic engine (12, 14) includes first thermodynamic elements (12) for generating a standing acoustic wave in a selected medium. An acoustic refrigerator (16, 26, 28) includes second thermodynamic elements (16) located in the standing wave for generating a relatively cold temperature at a first end of the second thermodynamic elements (16) and a relatively hot temperature at a second end of the second thermodynamic elements (16). A resonator volume (18) cooperates with the first and second thermodynamic elements (12, 16) to support the standing wave. To accommodate the high heat fluxes required for heat transfer to/from the first and second thermodynamic elements (12, 16), first heat pipes (24, 26) transfer heat from the heat load (22) to the second thermodynamic elements (16) and second heat pipes (28, 32) transfer heat from first and second thermodynamic elements (12, 16) to the borehole environment.

Acoustic detection of pneumothorax

NASA Astrophysics Data System (ADS)

Mansy, Hansen A.; Royston, Thomas J.; Balk, Robert A.; Sandler, Richard H.

2003-04-01

This study aims at investigating the feasibility of using low-frequency (<2000 Hz) acoustic methods for medical diagnosis. Several candidate methods of pneumothorax detection were tested in dogs. In the first approach, broadband acoustic signals were introduced into the trachea during end-expiration and transmitted waves were measured at the chest surface. Pneumothorax was found to consistently decrease pulmonary acoustic transmission in the 200-1200-Hz frequency band, while less change was observed at lower frequencies (p<0.0001). The ratio of acoustic energy between low (<220 Hz) and mid (550-770 Hz) frequency bands was significantly different in the control (healthy) and pneumothorax states (p<0.0001). The second approach measured breath sounds in the absence of an external acoustic input. Pneumothorax was found to be associated with a preferential reduction of sound amplitude in the 200- to 700-Hz range, and a decrease of sound amplitude variation (in the 300 to 600-Hz band) during the respiration cycle (p<0.01 for each). Finally, chest percussion was implemented. Pneumothorax changed the frequency and decay rate of percussive sounds. These results imply that certain medical conditions may be reliably detected using appropriate acoustic measurements and analysis. [Work supported by NIH/NHLBI #R44HL61108.

Acoustic Liners for Turbine Engines

NASA Technical Reports Server (NTRS)

Jones, Michael G (Inventor); Grady, Joseph E (Inventor); Heidmann, James D. (Inventor); Kiser, James D. (Inventor); Miller, Christopher (Inventor)

2016-01-01

An improved acoustic liner for turbine engines is disclosed. The acoustic liner may include a straight cell section including a plurality of cells with straight chambers. The acoustic liner may also include a bent cell section including one or more cells that are bent to extend chamber length without increasing the overall height of the acoustic liner by the entire chamber length. In some cases, holes are placed between cell chambers in addition to bending the cells, or instead of bending the cells.

Robust analysis method for acoustic properties of biological specimens measured by acoustic microscopy

NASA Astrophysics Data System (ADS)

Arakawa, Mototaka; Mori, Shohei; Kanai, Hiroshi; Nagaoka, Ryo; Horie, Miki; Kobayashi, Kazuto; Saijo, Yoshifumi

2018-07-01

We proposed a robust analysis method for the acoustic properties of biological specimens measured by acoustic microscopy. Reflected pulse signals from the substrate and specimen were converted into frequency domains to obtain sound speed and thickness. To obtain the average acoustic properties of the specimen, parabolic approximation was performed to determine the frequency at which the amplitude of the normalized spectrum became maximum or minimum, considering the sound speed and thickness of the specimens and the operating frequency of the ultrasonic device used. The proposed method was demonstrated for a specimen of malignant melanoma of the skin by using acoustic microscopy attaching a concave transducer with a center frequency of 80 MHz. The variations in sound speed and thickness analyzed by the proposed method were markedly smaller than those analyzed by the method based on an autoregressive model. The proposed method is useful for the analysis of the acoustic properties of bilogical tissues or cells.

Impact-acoustics inspection of tile-wall bonding integrity via wavelet transform and hidden Markov models

NASA Astrophysics Data System (ADS)

Luk, B. L.; Liu, K. P.; Tong, F.; Man, K. F.

2010-05-01

The impact-acoustics method utilizes different information contained in the acoustic signals generated by tapping a structure with a small metal object. It offers a convenient and cost-efficient way to inspect the tile-wall bonding integrity. However, the existence of the surface irregularities will cause abnormal multiple bounces in the practical inspection implementations. The spectral characteristics from those bounces can easily be confused with the signals obtained from different bonding qualities. As a result, it will deteriorate the classic feature-based classification methods based on frequency domain. Another crucial difficulty posed by the implementation is the additive noise existing in the practical environments that may also cause feature mismatch and false judgment. In order to solve this problem, the work described in this paper aims to develop a robust inspection method that applies model-based strategy, and utilizes the wavelet domain features with hidden Markov modeling. It derives a bonding integrity recognition approach with enhanced immunity to surface roughness as well as the environmental noise. With the help of the specially designed artificial sample slabs, experiments have been carried out with impact acoustic signals contaminated by real environmental noises acquired under practical inspection background. The results are compared with those using classic method to demonstrate the effectiveness of the proposed method.

Processing and Analysis of Multibeam Sonar Data and Images near the Yellow River Estuary

NASA Astrophysics Data System (ADS)

Tang, Q.

2017-12-01

Yellow River Estuary is a typical high-suspended particulate matter estuary in the world. A lot of sediments from Yellow River and other substances produced by human activity cause high-concentration suspended matter and depositional system in the estuary and adjacent water area. Multibeam echo sounder (MBES) was developed in the 1970s, and it not only provided high-precision bathymetric data, but also provided seabed backscatter strength data and water column data with high temporal and spatial resolution. Here, based on high-precision sonar data of the seabed and water column collected by SeaBat7125 MBES system near the Yellow River Estuary, we use advanced data and image processing methods to generate seabed sonar images and water suspended particulate matter acoustic images. By analyzing these data and images, we get a lot of details of the seabed and whole water column features, and we also acquire their shape, size and basic physical characteristics of suspended particulate matters in the experiment area near the Yellow River Estuary. This study shows great potential for monitoring suspended particulate matter use MBES, and the research results will contribute to a comprehensive understanding of sediment transportation, evolution of river trough and shoal in Yellow River Estuary.

Crack classification in concrete beams using AE parameters

NASA Astrophysics Data System (ADS)

Bahari, N. A. A. S.; Shahidan, S.; Abdullah, S. R.; Ali, N.; Zuki, S. S. Mohd; Ibrahim, M. H. W.; Rahim, M. A.

2017-11-01

The acoustic emission (AE) technique is an effective tool for the evaluation of crack growth. The aim of this study is to evaluate crack classification in reinforced concrete beams using statistical analysis. AE has been applied for the early monitoring of reinforced concrete structures using AE parameters such as average frequency, rise time, amplitude counts and duration. This experimental study focuses on the utilisation of this method in evaluating reinforced concrete beams. Beam specimens measuring 150 mm × 250 mm × 1200 mm were tested using a three-point load flexural test using Universal Testing Machines (UTM) together with an AE monitoring system. The results indicated that RA value can be used to determine the relationship between tensile crack and shear movement in reinforced concrete beams.

Deep Water Ocean Acoustics

DTIC Science & Technology

2016-12-22

in both the energy received and the travel time , both exhibiting strong 3D propagation. A paper was published on using noise correlations to estimate...3-5 Hz. 3.2. Passive Acoustic Thermometry From theoretical considerations it follows that the acoustic travel time between two sensors can be...obtained from the ambient noise field. In underwater acoustics, this travel time strongly depends on the depth and temperature and to a lesser extent

Review of Combustion-acoustic Instabilities

NASA Technical Reports Server (NTRS)

Oyediran, Ayo; Darling, Douglas; Radhakrishnan, Krishnan

1995-01-01

Combustion-acoustic instabilities occur when the acoustic energy increase due to the unsteady heat release of the flame is greater than the losses of acoustic energy from the system. The problem of combustion-acoustic instability is a concern in many devices for various reasons, as each device may have a unique mechanism causing unsteady heat release rates and many have unique boundary conditions. To accurately predict and quantify combustion-acoustic stabilities, the unsteady heat release rate and boundary conditions need to be accurately determined. The present review brings together work performed on a variety of practical combustion devices. Many theoretical and experimental investigations of the unsteady heat release rate have been performed, some based on perturbations in the fuel delivery system particularly for rocket instabilities, while others are based on hydrodynamic processes as in ramjet dump combustors. The boundary conditions for rocket engines have been analyzed and measured extensively. However, less work has been done to measure acoustic boundary conditions in many other combustion systems.

Improved Acoustic Blanket Developed and Tested

NASA Technical Reports Server (NTRS)

1996-01-01

Acoustic blankets are used in the payload fairing of expendable launch vehicles to reduce the fairing's interior acoustics and the subsequent vibration response of the spacecraft. The Cassini spacecraft, to be launched on a Titan IV in October 1997, requires acoustic levels lower than those provided by the standard Titan IV blankets. Therefore, new acoustic blankets were recently developed and tested to reach NASA's goal of reducing the Titan IV acoustic environment to the allowable levels for the Cassini spacecraft.

Genetic, morphological, and acoustic evidence reveals lack of diversification in the colonization process in an island bird.

PubMed

Illera, Juan Carlos; Palmero, Ana M; Laiolo, Paola; Rodríguez, Felipe; Moreno, Ángel C; Navascués, Miguel

2014-08-01

Songbirds with recently (i.e., early Holocene) founded populations are suitable models for studying incipient differentiation in oceanic islands. On such systems each colonization event represents a different evolutionary episode that can be studied by addressing sets of diverging phenotypic and genetic traits. We investigate the process of early differentiation in the spectacled warbler (Sylvia conspicillata) in 14 populations separated by sea barriers from three Atlantic archipelagos and from continental regions spanning from tropical to temperate latitudes. Our approach involved the study of sexual acoustic signals, morphology, and genetic data. Mitochondrial DNA did not provide clear population structure. However, microsatellites analyses consistently identified two genetic groups, albeit without correspondence to subspecies classification and little correspondence to geography. Coalescent analyses showed significant evidence for gene flow between the two genetic groups. Discriminant analyses could not correctly assign morphological or acoustic traits to source populations. Therefore, although theory predicting that in isolated populations genetic, morphological, or acoustic traits can lead to radiation, we have strikingly failed to document differentiation on these attributes in a resident passerine throughout three oceanic archipelagos. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Prediction and Measurement of the Vibration and Acoustic Radiation of Panels Subjected to Acoustic Loading

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Rizzi, Stephen A.

1995-01-01

Interior noise and sonic fatigue are important issues in the development and design of advanced subsonic and supersonic aircraft. Conventional aircraft typically employ passive treatments, such as constrained layer damping and acoustic absorption materials, to reduce the structural response and resulting acoustic levels in the aircraft interior. These techniques require significant addition of mass and only attenuate relatively high frequency noise transmitted through the fuselage. Although structural acoustic coupling is in general very important in the study of aircraft fuselage interior noise, analysis of noise transmission through a panel supported in an infinite rigid baffle (separating two semi-infinite acoustic domains) can be useful in evaluating the effects of active/adaptive materials, complex loading, etc. Recent work has been aimed at developing adaptive and/or active methods of controlling the structural acoustic response of panels to reduce the transmitted noise1. A finite element formulation was recently developed to study the dynamic response of shape memory alloy (SMA) hybrid composite panels (conventional composite panel with embedded SMA fibers) subject to combined acoustic and thermal loads2. Further analysis has been performed to predict the far-field acoustic radiation using the finite element dynamic panel response prediction3. The purpose of the present work is to validate the panel vibration and acoustic radiation prediction methods with baseline experimental results obtained from an isotropic panel, without the effect of SMA.

Effect of body position on vocal tract acoustics: Acoustic pharyngometry and vowel formants.

PubMed

Vorperian, Houri K; Kurtzweil, Sara L; Fourakis, Marios; Kent, Ray D; Tillman, Katelyn K; Austin, Diane

2015-08-01

The anatomic basis and articulatory features of speech production are often studied with imaging studies that are typically acquired in the supine body position. It is important to determine if changes in body orientation to the gravitational field alter vocal tract dimensions and speech acoustics. The purpose of this study was to assess the effect of body position (upright versus supine) on (1) oral and pharyngeal measurements derived from acoustic pharyngometry and (2) acoustic measurements of fundamental frequency (F0) and the first four formant frequencies (F1-F4) for the quadrilateral point vowels. Data were obtained for 27 male and female participants, aged 17 to 35 yrs. Acoustic pharyngometry showed a statistically significant effect of body position on volumetric measurements, with smaller values in the supine than upright position, but no changes in length measurements. Acoustic analyses of vowels showed significantly larger values in the supine than upright position for the variables of F0, F3, and the Euclidean distance from the centroid to each corner vowel in the F1-F2-F3 space. Changes in body position affected measurements of vocal tract volume but not length. Body position also affected the aforementioned acoustic variables, but the main vowel formants were preserved.

Introduction to Acoustics

NASA Astrophysics Data System (ADS)

Rossing, Thomas

This brief introduction may help to persuade the reader that acoustics covers a wide range of interesting topics. It is impossible to cover all these topics in a single handbook, but we have attempted to include a sampling of hot topics that represent current acoustical research, both fundamental and applied.

Acoustic emission linear pulse holography

DOEpatents

Collins, H.D.; Busse, L.J.; Lemon, D.K.

1983-10-25

This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

Acoustic communication in plant-animal interactions.

PubMed

Schöner, Michael G; Simon, Ralph; Schöner, Caroline R

2016-08-01

Acoustic communication is widespread and well-studied in animals but has been neglected in other organisms such as plants. However, there is growing evidence for acoustic communication in plant-animal interactions. While knowledge about active acoustic signalling in plants (i.e. active sound production) is still in its infancy, research on passive acoustic signalling (i.e. reflection of animal sounds) revealed that bat-dependent plants have adapted to the bats' echolocation systems by providing acoustic reflectors to attract their animal partners. Understanding the proximate mechanisms and ultimate causes of acoustic communication will shed light on an underestimated dimension of information transfer between plants and animals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acoustic emission monitoring system

DOEpatents

Romrell, Delwin M.

1977-07-05

Methods and apparatus for identifying the source location of acoustic emissions generated within an acoustically conductive medium. A plurality of acoustic receivers are communicably coupled to the surface of the medium at a corresponding number of spaced locations. The differences in the reception time of the respective sensors in response to a given acoustic event are measured among various sensor combinations prescribed by the monitoring mode employed. Acoustic reception response encountered subsequent to the reception by a predetermined number of the prescribed sensor combinations are inhibited from being communicated to the processing circuitry, while the time measurements obtained from the prescribed sensor combinations are translated into a position measurement representative of the location on the surface most proximate the source of the emission. The apparatus is programmable to function in six separate and five distinct operating modes employing either two, three or four sensory locations. In its preferred arrangement the apparatus of this invention will re-initiate a monitoring interval if the predetermined number of sensors do not respond to a particular emission within a given time period.

Truck acoustic data analyzer system

DOEpatents

Haynes, Howard D.; Akerman, Alfred; Ayers, Curtis W.

2006-07-04

A passive vehicle acoustic data analyzer system having at least one microphone disposed in the acoustic field of a moving vehicle and a computer in electronic communication the microphone(s). The computer detects and measures the frequency shift in the acoustic signature emitted by the vehicle as it approaches and passes the microphone(s). The acoustic signature of a truck driving by a microphone can provide enough information to estimate the truck speed in miles-per-hour (mph), engine speed in rotations-per-minute (RPM), turbocharger speed in RPM, and vehicle weight.

Transition section for acoustic waveguides

DOEpatents

Karplus, H.H.B.

1975-10-28

A means of facilitating the transmission of acoustic waves with minimal reflection between two regions having different specific acoustic impedances is described comprising a region exhibiting a constant product of cross-sectional area and specific acoustic impedance at each cross-sectional plane along the axis of the transition region. A variety of structures that exhibit this feature is disclosed, the preferred embodiment comprising a nested structure of doubly reentrant cones. This structure is useful for monitoring the operation of nuclear reactors in which random acoustic signals are generated in the course of operation.

Determining Equilibrium Position For Acoustical Levitation

NASA Technical Reports Server (NTRS)

Barmatz, M. B.; Aveni, G.; Putterman, S.; Rudnick, J.

1989-01-01

Equilibrium position and orientation of acoustically-levitated weightless object determined by calibration technique on Earth. From calibration data, possible to calculate equilibrium position and orientation in presence of Earth gravitation. Sample not levitated acoustically during calibration. Technique relies on Boltzmann-Ehrenfest adiabatic-invariance principle. One converts resonant-frequency-shift data into data on normalized acoustical potential energy. Minimum of energy occurs at equilibrium point. From gradients of acoustical potential energy, one calculates acoustical restoring force or torque on objects as function of deviation from equilibrium position or orientation.

High-sensitivity fiber optic acoustic sensors

NASA Astrophysics Data System (ADS)

Lu, Ping; Liu, Deming; Liao, Hao

2016-11-01

Due to the overwhelming advantages compared with traditional electronicsensors, fiber-optic acoustic sensors have arisen enormous interest in multiple disciplines. In this paper we present the recent research achievements of our group on fiber-optic acoustic sensors. The main point of our research is high sensitivity interferometric acoustic sensors, including Michelson, Sagnac, and Fabry-Pérot interferometers. In addition, some advanced technologies have been proposed for acoustic or acoustic pressure sensing such as single-mode/multimode fiber coupler, dual FBGs and multi-longitudinal mode fiber laser based acoustic sensors. Moreover, our attention we have also been paid on signal demodulation schemes. The intensity-based quadrature point (Q-point) demodulation, two-wavelength quadrature demodulation and symmetric 3×3 coupler methodare discussed and compared in this paper.

Verification of Ares I Liftoff Acoustic Environments via the Ares Scale Model Acoustic Test

NASA Technical Reports Server (NTRS)

Counter, Douglas D.; Houston, Janice D.

2012-01-01

Launch environments, such as Liftoff Acoustic (LOA) and Ignition Overpressure (IOP), are important design factors for any vehicle and are dependent upon the design of both the vehicle and the ground systems. The NASA Constellation Program had several risks to the development of the Ares I vehicle linked to LOA which are used in the development of the vibro-acoustic environments. The risks included cost, schedule and technical impacts for component qualification due to high predicted vibro-acoustic environments. One solution is to mitigate the environment at the component level. However, where the environment is too severe to mitigate at the component level, reduction of the launch environments is required. The Ares I Scale Model Acoustic Test (ASMAT) program was implemented to verify the predicted Ares I launch environments and to determine the acoustic reduction for the LOA environment with an above deck water sound suppression system. The test article included a 5% scale Ares I vehicle model, tower and Mobile Launcher. Acoustic and pressure data were measured by approximately 200 instruments. The ASMAT results are compared to the Ares I LOA predictions and water suppression effectiveness results are presented.

Broadband unidirectional acoustic cloak based on phase gradient metasurfaces with two flat acoustic lenses

NASA Astrophysics Data System (ADS)

Wang, Xiao-Peng; Wan, Le-Le; Chen, Tian-Ning; Song, Ai-Ling; Wang, Fang

2016-07-01

Narrow bandwidth and bulky configuration are the main obstacles for the realization and application of invisible cloaks. In this paper, we present an effective method to achieve broadband and thin acoustic cloak by using an acoustic metasurface (AMS). In order to realize this cloak, we use slitted unit cells to design the AMS due to the advantage of less energy loss, broad operation bandwidth, and subwavelength thickness. According to the hyperboloidal phase profile along the AMS, the incident plane waves can be focused at a designed focal spot by the flat lens. Furthermore, broadband acoustic cloak is obtained by combining two identical flat lenses. The incident plane waves are focused at the center point in between of the two lenses by passing through one lens, and then recovered by passing through the other one. However, they cannot reach the cloaked regions in between of the two lenses. The simulation results can verify the non-detectability effect of the acoustic cloak. Our study results provide an available and simple approach to experimentally achieve the acoustic cloak, which can be used in acoustic non-detectability for large objects.

Determination of the viscous acoustic field for liquid drop positioning/forcing in an acoustic levitation chamber in microgravity

NASA Technical Reports Server (NTRS)

Lyell, Margaret J.

1992-01-01

The development of acoustic levitation systems has provided a technology with which to undertake droplet studies as well as do containerless processing experiments in a microgravity environment. Acoustic levitation chambers utilize radiation pressure forces to position/manipulate the drop. Oscillations can be induced via frequency modulation of the acoustic wave, with the modulated acoustic radiation vector acting as the driving force. To account for tangential as well as radial forcing, it is necessary that the viscous effects be included in the acoustic field. The method of composite expansions is employed in the determination of the acoustic field with viscous effects.

Acoustic energy exchange through flow turning

NASA Astrophysics Data System (ADS)

Baum, Joseph D.

1987-01-01

A numerical investigation of the mechanisms of acoustic energy exchange between the mean and acoustic flow fields in resonance chambers, such as rocket engines, is reported. A noniterative linearized block implicit scheme was used to solve the time-dependent compressible Navier-Stokes equations. Two test cases were investigated: acoustic wave propagation in a tube with a coexisting sheared mean flow (the refraction test) and acoustic wave propagation in a tube where the mean sheared flow was injected into the tube through its lateral boundary (the flow turning study). For flow turning, significant excitation of mean flow energy was observed at two locations: at the edge of the acoustic boundary layer and within a zone adjacent to the acoustic boundary layer extending up to 0.1 radii away from the wall. A weaker streaming effect was observed for the refraction study, and only at the edge of the acoustic boundary layer. The total dissipation for the flow turning test was twice the dissipation for refraction.

Novel Fiber-Optic Ring Acoustic Emission Sensor.

PubMed

Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-13

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Clutter suppression and classification using twin inverted pulse sonar in ship wakes.

PubMed

Leighton, T G; Finfer, D C; Chua, G H; White, P R; Dix, J K

2011-11-01

Twin inverted pulse sonar (TWIPS) is here deployed in the wake of a moored rigid inflatable boat (RIB) with propeller turning, and then in the wake of a moving tanker of 4580 dry weight tonnage (the Whitchallenger). This is done first to test its ability to distinguish between scatter from the wake and scatter from the seabed, and second to test its ability to improve detectability of the seabed through the wake, compared to conventional sonar processing techniques. TWIPS does this by distinguishing between linear and nonlinear scatterers and has the further property of distinguishing those nonlinear targets which scatter energy at the even-powered harmonics from those which scatter in the odd-powered harmonics. TWIPS can also, in some manifestations, require no range correction (and therefore does not require the a priori environment knowledge necessary for most remote detection technologies).

Magneto-photo-acoustic imaging

PubMed Central

Qu, Min; Mallidi, Srivalleesha; Mehrmohammadi, Mohammad; Truby, Ryan; Homan, Kimberly; Joshi, Pratixa; Chen, Yun-Sheng; Sokolov, Konstantin; Emelianov, Stanislav

2011-01-01

Magneto-photo-acoustic imaging, a technique based on the synergy of magneto-motive ultrasound, photoacoustic and ultrasound imaging, is introduced. Hybrid nanoconstructs, liposomes encapsulating gold nanorods and iron oxide nanoparticles, were used as a dual-contrast agent for magneto-photo-acoustic imaging. Tissue-mimicking phantom and macrophage cells embedded in ex vivo porcine tissue were used to demonstrate that magneto-photo-acoustic imaging is capable of visualizing the location of cells or tissues labeled with dual-contrast nanoparticles with sufficient contrast, excellent contrast resolution and high spatial resolution in the context of the anatomical structure of the surrounding tissues. Therefore, magneto-photo-acoustic imaging is capable of identifying the nanoparticle-labeled pathological regions from the normal tissue, providing a promising platform to noninvasively diagnose and characterize pathologies. PMID:21339883