bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptual descriptors for the characterization of reflection fields in small rooms.
Authors: Romero-Perez Julian , Fazenda Bruno
Published: October 2010

This document aims to define a perceptual model that maps the characteristics of a given small room based on its reflection and diffuseness patterns. The study is done for the horizontal plane only and takes into account the impulse responses commonly found in small rooms. 2-D measurement methods based on intensity are applied in order to extract factors such as direction, time and strength of single reflections, and diffuseness estimates based on the latter part of the measured decay. These factors are then mapped to allow a description of their evolution over the room decay. The measured data are then weighted for in light of the current state of the art knowledge for perception of reflected energy within rooms. An objective measure is proposed which aligns the perceived features by listeners to a given measured response of a room.
Detection of blunt force trauma liver injuries using shear wave elastography.
Authors: Yu Jiao , Kaczkowski Peter , Crum Lawrence , Mitchell Stuart
Published: October 2010

Violent impacts, such as vehicle accidents, frequently yield injuries of the liver due to its size and its location in the abdominal cavity. Frequently these injuries are fractures which may lead to life-threatening hemorrhage. Currently, a fast means of non-invasively visualizing areas of injuries in the liver due to blunt force trauma does not exist; hence there is a need to develop better imaging modalities of hepatic injuries to assist in clinical assessments. In this study, we investigate the feasibility of visualizing liver fractures using shear wave elastography. We hypothesize that there is a shear modulus discontinuity between the two edges of a fracture, and we expect that these discontinuities can be observed from the imaging at the boundary of the split. In testing the hypothesis, we first use optical methods to track and study the displacements and motion trajectories of different regions of a hepatic injury phantom in response to shear wave excitations. Then, following Fink et al. [Proc.-IEEE Ultrason. Symp. 1767 (2002)], we implement similar methods with a Verasonics ultrasound system and examine the propagation of shear waves induced by the acoustic radiation force in tissue-mimicking phantoms and ex vivo liver. [Work supported by NIH 1R01GM77318.]
Ultrasonic characterization of bone quality based on Bayesian probability theory.
Authors: Anderson Christian C. , Bretthorst G. Larry , Holland Mark R. , Miller James G
Published: October 2010

The hypothesis that underlies the approach to be reported is that ultrasonic properties obtained using Bayesian probability theory can produce reliable estimates of bone quality and fracture risk. A key factor in this approach is to provide quantitative estimates of the confidence to be associated with the derived values of speed of sound (SOS) and frequency dependence of attenuation or broadband ultrasonic attenuation (BUA). Our laboratory demonstrated that when overlapping fast and slow compressional wave mode data are processed using phase spectroscopy and spectral subtraction techniques, interference effects may result in artifacts. In previous reports of studies of bone conducted in vitro, Bayesian probability theory was shown to be an effective method for extracting the ultrasonic properties of the individual fast and slow waves, even in the presence of substantial interference, whereas the same signals processed using conventional methods often exhibited anomalous features including non-causal negative dispersion. The focus of the present report is on the distribution of the probability density functions about their maximum values as a means for providing meaningful estimates of the confidence to be associated with the reported values for SOS and BUA for fast and slow wave modes. [Work supported by NIH R01HL40302, R01AR057433, and NSF CBET-0717830.]
Vibro-acoustography with rotational liner array transducer.
Authors: Alizad Azra , Urban Matthew W , Fatemi Mostafa
Published: October 2010

Vibro-acoustography with rectilinear raster scanning using confocal or linear array transducers have been reported before. Endo-cavity imaging requires a different type of scanning due to space limitation. This paper describes 3-D endo-cavity vibro-acoustography by a rotating linear array that scans the volume of interest. In this configuration a linear array is used to steer the beam electronically, which is combined with the rotational motion of the transducer to scan the beam in a cylindrical volume. This particular geometry produces special artifacts in the image. One such artifact is non-uniformity in signal power due to angular variations with respect to the hydrophone. Another artifact is related to the geometrical distortion in the image. In this paper, we will present examples of vibro-acoustography images with linear and rotational scanning and describe image characteristics and methods to reduce the artifacts. [Work supported by NIH Grant P50 CA91956P2.]
Ultrasonic modeling and measurements of cultured normal and malignant breast epithelial cells.
Authors: Doyle Timothy E. , Patel Hemang , Goodrich Jeffrey B. , Kwon Soonjo , Ambrose Brady J.
Published: October 2010

Developing an in vivo ultrasonic detection method for cancer would be valuable for applications such as the real-time assessment of surgical margins during breast conservation surgery. To study the spectral signatures of normal and malignant mammary epithelial cells, computer simulations and laboratory measurements were performed on 2-D cell cultures. The simulations modeled the cell monolayers as arrays of spherical cells containing spherical nuclei. Multipole expansions and boundary conditions were used to solve for the acoustic scattering from each cell. Backscattered wave fields were summed at the transducer face to calculate the measured ultrasonic amplitude. The measurements used a high-frequency NDT pulser-receiver with a broadband, unfocused 50-MHz immersion transducer. Waveforms were acquired by immersing the transducer in the growth media of cell culture well plates and collecting the first reflection from the well bottoms. Simulated spectra and preliminary data indicated that a confluent cell monolayer was detectable at 75–100 MHz. To reduce variability in test results, an in situ monitoring system was designed to periodically collect ultrasonic waveforms inside a tissue culture incubator over several days without moving the well plate or transducer during monolayer growth. Results from these and other tests will be presented. [Work supported by NIH 5R21CA131798-02.]
Conventional frequency evaluation of tumor cell death response in locally advanced breast cancer patients to chemotherapy treatment administration.
Authors: Papanicolau Naum , Dent Rebecca , Spayne Jacqueline , Kolios Michael , Sofroni Ervis , Iraji Sara , Czarnota Gregory
Published: October 2010

The aim of many cancer therapies is to induce cell death within a target tumor. A substantial body of research using in vitro and in vivo models has demonstrated that cell death can be detected via quantitative ultrasound techniques. This study investigates for the first time the potential to quantify tumor responses to therapy in patients, using spectral and signal envelope statistics analysis of ultrasound data. A clinical study was undertaken investigating the efficacy of ultrasound to quantify cell death in tumor responses with cancer treatment. Patients (n=20) with locally advanced breast cancer received anthracyline and taxane-based chemotherapy treatments. Data collection consisted of acquiring tumor images and radiofrequency data prior to treatment onset and at 4 times during treatment (weeks 1, 4, and 8, and preoperatively). Data indicate increases of approximately 9 dBr (±1.67) in ultrasound backscatter in patients who responded to treatment. Patients assessed as responding poorly demonstrated significantly lower increases (2.3 ± 1.7 dBr). Increases in 0-MHz intercept followed similar trends, while increases in spectral slope were observed from tumor regions demonstrating increases in tissue echogenicity. This study demonstrates the potential of ultrasound to quantify changes in tumors in response to cancer treatment administration in a clinical setting.
New absorbing materials obtained from recycled plastic bottles.
Authors: Alba Jesus , del Rey Romina
Published: October 2010

In controlling environmental noise, a lot of effort is put in place to optimize noise barriers. However, in doing so, the noise barriers are usually made of materials that are difficult to recycle. Currently, several studies are aimed to use textile-based materials, such as polyester wool instead of mineral wool, in manufacturing noise barriers. However, the pure polyester chip is made of synthesized polymers obtained from petroleum, whose price has risen during the last years. In this work, alternative polyester wool obtained through processing the polyethylene terephthalate (PET) from recycled plastic bottles is presented. For comparison, the sound absorption material characteristic parameters are obtained for pure polyester fiber and the new polyester wool made from recycled plastic bottles. In addition, an empirical model to predict the acoustic behavior of recycled PET is proposed. Thus, the model can be used both to design and to optimize noise barriers.
Road traffic noise barriers based on recycled materials.
Authors: Alba Jesus , del Rey Romina , Ramis Jaime
Published: October 2010

One of the main corrective measures taken to reduce environmental noise produced by roads is using sound barriers. However, the construction of miles of noise barriers implies a high cost. One solution to reduce the costs is using recycled materials in the noise barriers, for example, plastic wastes, which has great environmental benefits. According to EN 1793-1 to 3:1998, the main acoustic characteristics of noise barriers are the sound absorption and the airborne sound insulation. On the other hand, the technical document CEN/TS 1793-5:2003 gives guidelines for determining the in situ sound reflection index, which is an important parameter because the reflections from the barrier may increase the background noise in the surrounding area. This method has not been validated for noise barriers having a relatively low airborne sound insulation. In this study, sound reflection index using the impulse method is obtained in the laboratory for a wide frequency range. Environmental designs of road traffic noise barriers based on recycled materials with minimum sound reflection index are obtained. Optimization of the acoustic characteristics of the designs allows one to reduce the annoyance in the vicinity of the noise barrier.
A simple empirical model for recycled polyurethane foams for acoustical applications.
Authors: del Rey Tormos Romina , Alba Fernández Jesús , Arenas Jorge P.
Published: October 2010

In this work, the acoustic behavior of recycled polyurethane foams is studied in the frequency domain. Other authors have described the behavior of porous materials based either on the flow resistance [Dunn & Davern] or the structural characteristics of the pores [Voronina]. The main objective of all these works has been the determination of the propagating constant and the characteristic impedance. Here, the propagating constant and the characteristic impedance are described as a function of the flow resistance. The flow resistance has been obtained from experimental measurements using the method proposed by Ingard & Dear. On the other hand, the normal incidence sound absorption coefficient values are obtained using the procedure described in the standard UNE-EN ISO 10534-2:2002. In this way, specific coefficients for recycled polyurethane foams are determined. These coefficients are later compared with the classical coefficients that describe the behavior of any open-pore material.
The acoustics of lip-excited animal horns.
Authors: Campbell Murray
Published: October 2010

For thousands of years the thrilling sound of the lip-excited animal horn has been a central feature of religious ceremonies, and has also played an important role in signaling and communication. It can be argued that all the brass instruments now in use in Western orchestras and bands have evolved from this common source. Modern brass instruments, however, have bore profiles which have been developed and refined over centuries of trial and error to serve specific musical functions. The internal bore profile of the animal horn is largely determined by the choice of horn: the maker has therefore little control over the frequencies of the air column acoustic modes. This paper discusses the different types of horn which have been commonly used to make musical instruments and explores the effect of the natural bore profile on the sounding properties of the instrument.
Acoustical analysis of musical traditional instruments from South-America.
Authors: Jimenez Hernandez Mario
Published: October 2010

The musical instruments are present in all of mankind’s history, and these have been built employing artisanal techniques gained by experience; these techniques are transmitted through generations of the instruments’ constructors. The inexistence of a formal method for the construction has the consequence that two similar instruments play different timbers and have contrasts in their acoustical characteristics. This fact has major relevance in the case of wind instruments because it is impossible to modify their structure. This paper presents the acoustical analysis of two different musical instruments from South-America, Quenas and Zampoñas, with emphasis in the musical scale, the techniques of construction, and the physical models for these instruments.
Acoustic summary as a tool for soundscape analysis and design.
Authors: Botteldooren Dick , Oldoni Damiano , De Coensel Bert
Published: October 2010

The soundscape approach to designing sonic environments recognizes the importance of the sounds that can be heard by the attentive listener. These sounds not only contribute to the affective component of appraisal of the sonic environment but also carry the cultural identity of the neighborhood. For the purpose of discussion and communication in the soundscape design process, it is suggested to use a compilation of typical sounds amended with a sample of unusual sounds. To create such an acoustic summary automatically, a clustering system based on self-organizing maps (also called Kohonen networks) using well-chosen acoustical features is proposed. In addition, an oscillating neural network groups the sound into auditory streams with well defined duration. The proposed computational system continuously learns to identify the sounds that surround it and allows retrieving prototypical sounds for all identified clusters of sounds. Since the system is trained for a specific environment, the acoustic summary thus produced could contain more diverse samples of categories of sounds that often occur at this location. Listening panels, architects, and urban planners can use the acoustic summary for shaping their personal mental image of an existing or future sonic environment.
Interventions through the soundscape approach.
Authors: Schulte-Fortkamp Brigitte , Brooks Bennett
Published: October 2010

Instead of calculations about noise, the soundscape approach uses the experience of the people who live in the environment as an essential part of the evaluation and also of the design of the environment. This is proven to lead to novel and effective solutions regarding developments and changes in diverse areas. Recent decisions regarding soundscape research as in the ISO TC43/S1/WG54 and the COST project TD 0804 will support and connect these promising procedures and solutions in a network. In this presentation, experiences in projects concerning methods and procedures with regard to upcoming research in diverse fields of changes will be addressed. For the evaluation procedure, it is needed to integrate physical and perceptual context variables, and to prove that soundscape is not just a matter of noise level reduction but accounts for peoples concerns and acceptance. Therefore, soundscape approaches will guide the paths in future research concerning community noise.
Participation of public and stakeholders in the design of urban quiet areas.
Authors: Luzzi Sergio , Bellomini Raffaella , Borchi Francesco
Published: October 2010

The strategic action plan and the city plan for noise control and reduction of Florence (Italy) have been developed by the authors, integrating the planned actions, in the frame of HUSH, a LIFE+ EU funded project concerning the Harmonization of Urban noise reduction Strategies for Homogeneous plans. Quiet areas and relative actions have been planned according to a Participatory Design approach, connected with the multi-sensorial conception of landscape and its perception and following a model aiming to actively involve the public, considering the real and potential stakeholders’ opinions. In a number of squares, green areas and urban open spaces, chosen for stressing the method, actions directly involve the users of each place, through a process of participation and communication that increase the sense of belonging to the place itself, reinforcing the idea of community. Two case studies, regarding a square ideally divided in four connected areas with different soundscapes and different users and a wide green area surrounding a widely attended primary school and annoyed by the close presence of a heavy traffic suburban street are presented.
Local sonic wonders: Tectonics of measuring, modeling, and mapping aspects of soundscapes.
Authors: Siebein Gary W. , Siebein Keely M. , Tsaih Lucky , Park Sang Bum , Shin Sang Bong
Published: October 2010

Soundscape theory is based on the premise that the ambient sound in an area is composed of a series of specific acoustic events that can be measured and modeled. In order to technically execute the process of measuring the specific acoustic events in a soundscape, each event must first be identified in an acoustic taxonomy and then measured in sufficient detail to allow modeling of the perceptually robust aspects of the event, so auralizations or other assessments of existing and future sounds can be made. The evaluation of site planning strategies was based on whether the sound levels at the proposed site would first comply with the noise ordinance, and second, be audible at homes when windows were open late at night at levels that might disturb sleep or be otherwise annoying. Full size simulations of sounds from entertainment establishments played into neighborhoods so people could listen to proposed sounds in their homes and yards as a method to allow citizens to participate in public hearings where acoustic impacts are addressed was also used.
A new tranquility rating tool and the role of audio and visual interactions.
Authors: Horoshenkov Kirill , Pheasant Robert , Watts Greg , Whitaker David , Kang Jian
Published: October 2010

Restorative environments which enable individuals to recover the sense of well-being are becoming increasingly important. These environments are characterized by an enhanced level of tranquility. Therefore, measuring the optimum relationship between the landscape and soundscape characteristics and the tranquility rating of these spaces is essential for their design and maintenance. In order to understand the key factors which affect the tranquillity construct, a large volume of audio and visual data has been collected across a representative range of landscapes in the UK. These data have been analyzed objectively by studying the temporal and spectral characteristics of the recorded sounds and the proportion of the natural and contextual features present in the video clips. The tranquility rating of these landscapes has been obtained from subjective experiments on 44 subjects to whom uni- and bimodal stimuli have been presented in a separate experiment. The results of these experiments make possible to objectively measure the key components of the tranquility construct and determine their relative importance in the design of a restorative space. On this basis, new relations between the tranquility rating, sound pressure level, loudness characteristics, and the visual quality of the scene have been derived.
Keep it quiet: Acoustic design and the High Line.
Authors: Adams Tyler , Braasch Jonas
Published: October 2010

The High Line is a newly opened park, developed on an abandoned elevated train line located along the West Side of Manhattan. The park was designed by the landscape firm James Corner Field Operations and architects Diller, Scofidio, and Renfro, whose design mantra for the project was “Keep it simple, keep it wild, keep it quiet, keep it slow.” The location and elevation of the High Line make it an unorthodox site for a park, particularly in terms of sound, as the park traverses over and along streets and intersections, offers sightlines to the adjacent West Side Highway, exposes visitors to HVAC noise on nearby roofs, and is parallel to a helicopter flight path. This calls into question the design objectives of the architects to “Keep it quiet.” Through interviews, public surveys, recordings, and observations, our goal was to determine the role acoustic design played in the overall design process and assess the design’s success by evaluating the attitudes and expectations of the park visitors. Following this, it can be speculated as to how the sound environment contributes to the overall critical acclaim of the High Line and provide some suggestions for improvements and ideas for future acoustic design strategies.
The influence of the ground on the attenuation properties of sonic crystal barriers.
Authors: Sanchez-Perez J. V. , Romero-Garcia V. , Attenborough K. , Taherzadeh S. , Chong A.
Published: October 2010

Sonic crystals (SCs) are periodic arrangement of scatterers embedded in a fluid medium with different elastic properties. One of the main acoustical properties of these materials is the existence of ranges of frequencies where the transmission is forbidden according to Bragg’s law of diffraction. This property enables the use of these devices in the design of acoustic screens for environmental noise. One factor that can affect the attenuation of these systems is the presence of the ground. Experimental, numerical, and analytical results are shown in this work, related to the influence of the hard ground on the attenuation properties of 2-D SC consisting of rigid cylinder arrays with the cylinder axes parallel to the ground.
Modal analysis and transient response of a sonic crystal room.
Authors: Spiousas Ignacio , Eguia Manuel C.
Published: October 2010

New acoustic metamaterials offer promising applications, ranging from noise barriers to acoustical diodes. This work applies large-sized sonic crystals to room acoustics. A model of a rectangular room where the walls were replaced by 2-D sonic crystals is proposed. In this way, the room is conceived as a rectangular cavity inside the crystal, and we expect highly nontrivial acoustical properties for such a space. The main interest is focused on creating a new venue for contemporary music performance and site-specific sound art. Both practices could take advantage of the expected unusual acoustical features of this space (sonic crystal room). In order to characterize the room, a finite element model (FEM) modal analysis is performed and spatial impulse responses of the system are modeled using transient acoustic FEM. Several parameters of room quality evaluation are computed from the impulse responses.
Improved active control algorithm for marine diesel two-stage vibration isolation system.
Authors: Xiao Bin
Published: October 2010

The active control technology was carried out on the marine diesel two-stage vibration isolation system (MDTVIS); the active control technology was able to make up for passive vibration isolation technology in the low-frequency range. The construction of a secondary path was one of the most important sectors, which had a full impact on active vibration isolation performance. Nonlinear components comprised the secondary path, which were principally the nonlinear vibration of multi-degrees of freedom in the practical MDTVIS and the nonlinear control path in the hydraulic servo actuator. The nonlinearity was not ignorable in coping with the second path, so that the vibration isolation performance was greatly influenced by the secondary path in the active control technology with the classic adaptive comb-type filter. By combining the model reference adaptive inverse control strategy with the nonlinear robust control technology, the linearity control algorithm was designed, and then the classic adaptive comb-type filter algorithm was carried out for the new system; herein the hybrid control strategy was constructed to apply to the secondary path in the practical MDTVIS. The proposed hybrid control strategy was able to improve the initial active vibration isolation control algorithm with an adaptive comb-type filter and overcome shortcomings of the vibration strengthened in some multi-harmonic-frequency sites in the low-frequency range. The total performance of vibration isolation coupling with multi-path was improved in balance.
The influence of Poisson’s ratio on the excitability of the first higher symmetric (S1) zero-group velocity Lamb mode.
Authors: Ryden Nils
Published: October 2010

The impact echo (IE) method is widely used in non-destructive testing of concrete plate like structures but has proved difficult to apply on asphalt pavements. Observed low IE resonance amplitudes on asphalt have been attributed to larger material damping but the present study shows that it may also be an effect from a larger Poisson’s ratio. The IE frequency corresponds to the stationary resonance of the S1 Lamb mode at zero-group velocity (ZGV). It has been previously shown that the S1 ZGV Lamb mode only exists below a Poisson’s ratio of 0.45. [Prada et al., J. Acoust. Soc. Am. 124, 203–212 (2008).] The present study investigates the magnitude of the excitability and damping ratio of the S1 ZGV mode as a function of Poisson’s ratio. The frequency response from a point source is predicted using a finite element model. Results show that the excitability decreases with increasing Poisson’s ratio. The excitability of the S1 ZGV mode is about twice as high at a Poisson’s ratio of 0.18 compared to 0.30, which are representative values for concrete and asphalt, respectively. The modal damping ratio increases with Poisson’s ratio, causing an overall lower IE resonance amplitude at higher values of Poisson’s ratio.
Vibroacoustic behavior of cylindrical shell: Comparison of numerical approach and experimental measurement.
Authors: El Hafidi Ali , Lay Beatrice
Published: October 2010

The control of the vibratory and sound level inside the planes is a significant commercial argument which has direct consequences on comfort, health, and safety of the users. Viscoelastic multilayered patches, called systems passive constrained layer damping (PCLD), based on the damping brought by viscoelastic materials are passive systems used to reduce the vibratory levels. The objective of this presentation is to show, using numerical and experimental studies, that this damping applied to the structure has an influence on the sound transmission (outside/inside), which makes it possible to increase the noise reduction. The experimental study is carried out on a model made up of a cylindrical shell coupled to a cavity and excited by a white noise. The cylindrical shell is equipped with a damping device implying viscoelastic materials which work in shearing. Parallel to this, a numerical study was carried out to (1) predict the vibroacoustic behavior of the stiffened cylindrical shell coupled with the cavity and (2)validate the vibration attenuation brought by the PCLD technology in terms of acoustic performances. The high modal density and the big vibroacoustic size of the model are two problems for numerical modeling. These studies show that numerical and experimental results are similar.
Modeling and validation of the response of ribbed panels using numerical methods and experimental data.
Authors: González M. A. , Jordan R. , Lenzi A.
Published: October 2010

Rib-reinforced panels are widely used by the aeronautical industry. This kind of structure is typical on the fuselage of airplanes. Under flight conditions, the fuselage suffers several dynamic loads, which may be localized or distributed. Consequently, the vibration response will produce noise inside the cabin. On the other hand, the passive control based on surface damping treatments by the addition of viscoelastic material can reduce the levels of structural vibration and the noise generated. In this paper results of experimental data and numerical models in finite element method about the vibration response in aeronautical panels are introduced by comparison of the response itself whether considered a viscoelastic material or not.
Detecting vibration damping from thermal images.
Authors: Bridgeo Kyle R. , McDaniel J. Gregory
Published: October 2010

Available technologies for producing thermal images promise temperature sensitivity on the order of 25 mK. This sensitivity prompts the present investigation, which is concerned with defining circumstances in which thermal images may be used to detect and perhaps measure damping effects. Ultimately, thermal images may lead to a spatial map of damping effectiveness that would be of great use in improving the design and configuration of vibration damping treatments. A frequency-domain analysis is presented in which a passive structure with damping is excited mechanically and the resulting change in temperature is estimated based on the assumption that local damped energy is fully converted to heat. A strategy for exciting the structure, based in part on modal theory, considers two opposing objectives. One wishes to excite the structure over the longest possible time interval so that a larger temperature difference will be produced. This will naturally result in a higher signal-to-noise ratio. However, longer time intervals will allow heat to conduct and convect in the structure and to the surroundings, thus hindering one’s ability to spatially localize the origin of damped energy. Optimal balance between the objectives is achieved and illustrated in numerical examples. [Work supported by ONR under Grant #N000140810531.]
Validation of a switchable stiffness system for shock isolation.
Authors: Ledezma-Ramirez Diego , Elizondo-Garza Fernando J. , Ferguson Neil
Published: October 2010

The idea of a switchable stiffness device intended to provide improved shock isolation is presented. A control strategy in two stages, namely, the reduction of stiffness during a shock and the later suppression of residual vibration switching between minimum and maximum stiffness values is analyzed. Experimental validation is presented, where a switchable stiffness device based on magnetic forces is developed. It is found that the implementation of switchable stiffness can yield better shock isolation performance.
Forensic speaker recognition: Comparison and validation of three generations of automatic systems.
Authors: Meuwly Didier
Published: October 2010

The first aim of this paper is to demonstrate the improvement of automatic speaker recognition systems used for forensic evaluation over a period of 12 years. The second aim consists of exploring how the results of different systems can be compared and their improvement measured. The same set of experiments is replicated on three different systems: the original LR-based ASR system from 1998 (ASPIC I), the EPFL ASR system of 2004 (ASPIC II), and the Agnitio ASR system (BATVOX) from 2010. The reference database, Polyphone, consisting of 2000 male and 2000 female speakers from the French part of Switzerland, and the forensic database, Polyphone-IPSC, consisting of 16 male and 16 female speakers from the same region, were used to test the following forensic conditions: spontaneous speech, disguised speech, PSTN, GSM, signal to noise ratio from 30 to −3 dB, digital and analog recording, and close set of family related speakers. The results are visualized using Tippett plots. The refinement and calibration of the systems are measured and compared using the log-likelihood-ratio cost (Cllr). Finally, the value, in terms of forensic validation, of the methodology used and the results produced are discussed.
Passive matched-field inversion using a short vertical array.
Authors: DelBalzo Donald R. , Leclere James H. , Klicka Joseph
Published: October 2010

Shallow-water acoustic predictions are severely limited by uncertainty in sediment property characteristics. Inverse methods with controlled active sources have been used to estimate seabed properties; however, some applications require a covert approach. This work is focused exclusively on passive inversion using signals from surface ships-of-opportunity. The simulation study addresses the accuracy of low-frequency (100–300 Hz) matched-field correlations using broadband signals from surface ships with unknown source levels at unknown ranges. Matched-field techniques are applied in a realistic shallow-water environment with short vertical line arrays of various lengths and high signal-to-noise ratios. The simulations indicate significant potential for accurate estimates of thick-sediment characterizations of grain size out to ranges of tens of water depths in shallow water, despite moderate mismatch conditions in the environmental model. The relationship between frequency, water depth, and aperture size is also examined. [Work sponsored by NAVAIR.]
Speed filtering to improve shallow water matched-field detection.
Authors: DelBalzo Donald R. , Leclere James H.
Published: October 2010

Passive acoustic sonars have difficulty in detecting quiet sources in noisy shallow-water environments. The standard approach to improve detection is to use a large aperture linear array of horizontally distributed hydrophones and azimuthal processing to increase the signal-to-noise ratio through beamforming. A newer approach is to exploit the acoustic interference of normal modes in shallow water and apply matched-field (model-to-data) correlation techniques to estimate source locations in depth and range using signals received on a linear vertical array. These localization techniques are not designed for the detection of quiet targets, and some applications preclude the use of vertical arrays. This work examines the utility of matched-field processing on linear and planar horizontal arrays on the ocean bottom in shallow water. A speed filter to eliminate higher-speed targets is applied. Then a track-before-detect strategy to convert matched-field localizations into source detections in various physical and acoustic environments is utilized. We show the advantages of planar compared to linear arrays to discriminate submerged from surface sources as a function of SNR. [Work sponsored by QNA.]
Rayleigh-non-Rayleigh mixtures for active sonar clutter.
Authors: Abraham Douglas , Gelb James , Oldag Andrew
Published: October 2010

False alarms in active sonar systems commonly come from natural and man-made inhomogeneities in the ocean environment. For example, fish, mud-volcanoes, rock outcrops, and ship-wrecks can all cause target-like false alarms called clutter. The sparse nature of the physical sources of clutter can lead to data most appropriately represented statistically as a mixture of two probability distribution functions (PDFs). The Rayleigh PDF is a natural choice for the background scattering, while there are many options to represent the clutter-source scattering. Expectation-maximization (EM) based algorithms are presented to estimate parameters for a Rayleigh-distributed background mixed with log-normal, generalized Pareto, Weibull, or K PDFs representing the clutter. The EM algorithm requires maximization of a weighted log-likelihood function, similar to maximum-likelihood parameter estimation. While the log-normal distribution yields closed-form estimates, the other PDFs do not. Thus, an EM-gradient algorithm is implemented for the generalized-Pareto and Weibull PDFs, while a method-of-moments algorithm is necessary for the K. Application of the estimation algorithm on real data ranging from near-Rayleigh to very-heavy-tailed illustrates the various models’ efficacy. [Work sponsored by ONR under Contract nos. N00014-09-C-0318 and N00014-06-G-0218-34.]
Active noise reduction in ventilation ducts.
Authors: Gaab Oliver , Sachau Delf
Published: October 2010

ANC is commonly used in several noise exposed areas. The basic idea has been extensively analyzed in literature, especially for the cancellation of sinusoidal noise in ducts. Here, the challenge for an ANC-system is the attenuation of undesired broadband noise in a ventilation duct with high air flow. In this case special consideration must be given toward the performance of the acoustic sensors while exposed to turbulent flow. The concept of a Swinbank-source in combination with an adaptive filter appears to fit well for the given problem. Furthermore, causality constraints concerning the feed forward adaptive controller are analyzed with respect to sensor and actuator placement. In an experimental setup with a duct of 3 m length and a diameter of 350 mm, noise attenuation of 14 dB in a frequency range from 50<f<450 H can be achieved downstream of the control source.
Extremely shallow underground imaging using optimum frequency range method.
Authors: Sugimoto Tsuneyoshi , Abe Touma
Published: October 2010

We propose a method of distinguishing a buried object using the optimum frequency response range corresponding to the vibration velocity. Air-borne sound and a scanning laser Doppler vibrometer are used for noncontact acoustic imaging in the extremely shallow underground. Flat speakers that have a sharp directivity are used as vibration sources. Plastic container, hollow steel can, unglazed pot, and stone are used as buried objects and they are buried in the sand about 2 cm deep. First, noise waves are used for the confirmation of the buried object’s frequency response range. The ground surface imaging result by scanning laser Doppler vibrometer is used to confirm the position of the buried objects. To confirm the frequency range, the difference of the vibration velocities is used. Next, burst waves are emitted again to make a clear image. The frequency of the burst waves is set near the frequency response range. Finally, the buried object’s frequency response range is checked again the same way. The clear image is made by using the optimum frequency. From the indoor experimental results, we confirmed the frequency response range of each buried objects and the effectiveness of our proposed method.
Representation of floating point with reconfigurable logic.
Authors: Jiménez Flores Armando , Schnadower Baram Isaac , Castillo Tapia Guillermo , Peńa Guerrero Maximino
Published: October 2010

Given the discreet nature of the digital systems and that the languages used in their design do not provide native instructions to handle floating point numbers, it is advisable to develop hardware solutions that allow the representation of this type of numbers in order to improve the precision and speed in applications related to signal analysis. In this document we show an algorithm that describes the floating point numbers, by means of Very High Speed Integrated Circuits Hardware Description Language (VHDL), to create the fundamental bases for the development of a floating point arithmetical unit that can be implanted in Field Programmable Gate Array (FPGA) devices and be applied in voice signal processing. Our algorithm uses the simple precision format of IEEE-754 standard, and the operation used as a test is an arithmetical sum. The results are by means of generated waveform with design tools of the Xilinx Company.
The feasibility of detecting a large plume of oil drops using low-to-mid frequency active sonar.
Authors: Ainslie M. A. , Beerens S. P. , Prevo R. , Zampolli M.
Published: October 2010

The use of long range active sonar in the frequency range 1–10 kHz is considered with regard to its potential for detecting large quantities of submerged oil drops. In the scenario considered, the drops are modeled as fluid spheres of radius of order 1 cm, for which the acoustic wavelength is large compared with the oil drop radius. This means that the volume backscattering strength of a cloud of oil (of given volume fraction) increases rapidly with increasing frequency. The implied requirement for the use of high frequency sound is balanced against the preference for low frequencies in order to reduce absorption in seawater. Detection performance is simulated for a background of bottom reverberation and ambient noise. It is shown that the optimum detection frequency depends on drop size, coverage distance, and ambient noise level. At the time of writing, the authors are exploring the possibility of carrying out measurements during the summer of 2010 to test the modelling results. If available in time, results from these measurements will be presented. The possibility of detection of oil by forward scattering in a bistatic geometry is also considered.
Volume scattering and reflectivity from Louisiana Sweet Crude oil measured at 200 and 400 kHz in the Gulf of Mexico, May 2010.
Authors: Wendelboe Gorm , Christoffersen Jesper , Maillard Eric
Published: October 2010

Between May 19 and 21, 2010, RESON and Terrasound conducted experiments with SeaBat 200- and 400-kHz multibeam systems in the Gulf of Mexico. Tests were carried out with a wide-opening-angle multibeam system and a narrow-opening-angle multibeam system. Volume scattering from oil contaminated water columns as well as non-polluted water columns were measured and comparisons were made in order to determine changes in volume scattering. Reflectivity from a water/oil interface was also measured. Results show a significant difference in volume backscatter between oil contaminated water columns and non-polluted water columns. The reflectivity from a water/oil interface is pronounced.
Passive acoustic monitoring to assess marine mammal population trends in vicinity of the Deepwater Horizon oil spill.
Authors: Sidorovskaia Natalia , Tiemann Christopher O. , Ioup George E. , Ioup Juliette W.
Published: October 2010

The area near the Deepwater Horizon incident was abundant with a variety of marine mammals, including endangered sperm whales and beaked whales. Our group, the Littoral Acoustic Demonstration Center (LADC), is in a unique position to assess short-term and long-term environmental impacts on marine mammal species in the immediate area of the oil spill source. LADC possesses multiple-year passive acoustic data in the vicinity of the oil spill, including an extensive 9-day visual and acoustic survey of marine mammals and the first recordings of the Gulf of Mexico beaked whales made in July 2007 just 9 miles from the Deepwater Horizon location. The previous recordings provide a baseline which, when combined with new measurements, can give important indicators of changes in the populations in response to the disaster. The paper reviews available population density estimation models based on acoustic recordings as applied to the LADC data. The baseline density estimations from acoustic data for sperm and beaked whales in the vicinity of the incident are presented and compared to available data derived from visual surveys.
Sound-speed fluctuations in the Philippine Sea.
Authors: Van Uffelen Lora J. , Worcester Peter F. , Dzieciuch Matthew A. , Colosi John A.
Published: October 2010

Observations from MicroCAT sensors deployed as part of the 2004 SPICEX experiment indicate that the Garrett–Munk internal wave energy spectrum at full strength appropriately describes the rms sound-speed fluctuations in the North Pacific in the region of the experimental deployment. Parabolic equation simulations incorporating sound-speed field perturbations consistent with this model show remarkable agreement with acoustic data both in intensity and travel time spread. The Philippine Sea is dynamically a very different region. In the recent PhilSea09 deployment, a single acoustic source mooring and an acoustic receiver mooring were outfitted with MicroCAT sensors. The hydrophone modules on the receiving array also housed calibrated thermistors. The fluctuations of these measurements will be compared with the Garrett–Munk spectrum to determine whether this model is accurate in this region of the Philippine Sea. Acoustic propagation models incorporating the observed fluctuations will be compared with acoustic measurements from the receiving array. [Work supported by ONR.]
Sound propagation in strongly range-dependent deep ocean environments with application to the Philippine Sea.
Authors: Rypina Irina I. , Udovydchenkov Ilya A. , Brown Michael G. , Dushaw Brian
Published: October 2010

Many mid-latitude deep ocean environments are characterized by strongly range-dependent sound speed structure associated with mesoscale variability, including internal tides. Often much of this variability is describable as a combination of barotropic and lowest baroclinic mode variability. There are reasons to anticipate that ocean structure of this type leads only to a relatively benign range-dependent modulation of underwater sound fields. These ideas will be explained and tested using ECCO2 state estimates in the Philippine Sea. [Work supported by the ONR.]
Deepwater acoustic propagation in the northern Philippine Sea: Comparison of modeled and observed ray travel times.
Authors: Cornuelle Bruce D. , Gopalakrishnan Ganesh , Dzieciuch Matthew A. , Worcester Peter F.
Published: October 2010

This presentation will report on comparisons between ray travel times computed in a model and observations in the Northern Philippine Sea (NPS). The model is the MITgcm, configured with 50 vertical levels and 1/12 deg resolution in a domain covering 17–27 deg north and from the western boundary to 140 deg East. It is forced by surface fluxes from NCEP and NOGAPS products, and assimilated HYCOM 1/12 deg output is used for initial and boundary conditions. Sound speed profiles taken from the model will be compared to those from climatologies and from Argo floats in the region. Ray arrival times calculated using the time evolution of the model over several years will be calculated. The arrival pattern and its variability will be compared to observations and to calculations in climatologies. Ray arrival and ray path stability will be analyzed to assess the utility of travel time measurements for estimating ocean structure. This is a step in preparation for a model-based analysis of the NPS.
Vertical directionality of low-frequency ambient noise in the Philippine Sea.
Authors: Wage Kathleen E. , Dzieciuch Matthew A. , Worcester Peter F.
Published: October 2010

Measurements of the vertical structure of deep ocean noise are important for understanding noise generation and propagation as well as for designing improved sonar processing algorithms. There have been relatively few measurements of the vertical directionality of low-frequency noise due to the large apertures required. Urick’s book (1983) describes the earliest work on vertical directionality, while the paper by Baggeroer et al. [J. Acoust. Soc. Am. 117] summarizes more recent results. Most of the previous experimental measurements of deep noise statistics were collected in either the Atlantic or the North Pacific. The PhilSea09 experiment provided an opportunity to measure the vertical directionality of noise in the Philippine Sea using a distributed vertical linear array (DVLA) deployed in 5500 m of water. The DVLA consisted of two subarrays, the first spanning the sound channel axis and the second located below the surface conjugate depth. The subarrays facilitate a comparison of deep sound channel noise with the noise below the critical depth, similar to the analysis done by Anderson for the North Pacific [J. Acoust. Soc. Am. 66]. This paper will present an analysis of the vertical directionality observed in the Philippine Sea during April/May of 2009. [Work sponsored by ONR.]