bluuebunny/crossref_metadata_2025 huggingface dataset:
Wave propagation model for acoustic evaluation of polymeric thin films.
Authors: Ju Hyeong Sick , Tittmann Bernhard R.
Published: March 2010

Polymeric thin films are fabricated on crystalline wafers to serve as a photoresist in lithography processes of semiconductors or MEMS. Essentially these film structures are viscoelastic layers on anisotropic substrates. Acoustic evaluation for these material structures requires an appropriate wave propagation model. This paper presents a leaky surface acoustic wave (LSAW) model for the evaluation of polymeric film integrity. Scanning acoustic microscopy (SAM) operating at relative high-frequency above 100 MHz is utilized to measure the LSAW velocity. For the use of SAM, the model modifies the pre-existing anisotropic layered model by employing hysteretic absorption in viscoelastic polymer and water-loading. The model produces the mean reflectance function and mean dispersion curve, which are specialized for spherical acoustic lenses. The predicted mean dispersion shows good agreement with LSAW velocities measured at several frequencies with spherical lenses.
Active vibration control modules for damping, compensation, measurement and dynamic testing.
Authors: Ryaboy Vyacheslav M.
Published: March 2010

The active vibration control module was introduced previously as part of active vibration damping system for optical tables and other precision vibration isolated platforms. This paper describes steps to expand the application of those modules to other tasks, namely, compensation of forced vibration in local areas and dynamic testing of structures. Vibration damping of most significant structural modes had been achieved using a small number of properly placed active dampers. This did not affect forced tonal vibration. Current state of the art does not offer a practically feasible way to suppress all vibration, forced and normal, over the total table surface. However, by placing vibration control modules around a local area of the table supporting a vibration sensitive device, it is possible to abate forced tonal vibration in this area. Feedback control for vibration compensation will be discussed along with experiments demonstrating stable concerted work of several vibration control modules. In application to dynamic testing, the actuator is excited by white noise, and the sensor signal is processed to calculate the dynamic compliance. The test data show that the vibration control modules can be used to measure dynamic compliance with precision comparable to that of dedicated vibration measurement systems.
When is a system random?
Authors: Lyon Richard H.
Published: March 2010

Statistical energy analysis (SEA) is a method for estimating structural acoustic transfer functions based on a statistical model of the system. The SEA model assumes random noise excitation in frequency bands and an underlying ensemble of “similar” systems. However, since the results of a SEA calculation are nearly always applied to a single system, there is a natural question of in what sense a single system can be random. A particular structural acoustics system is considered that displays both deterministic and random behavior with a distinct transition between the two. System parameters (damping, modal density, and coupling factors) are examined to see how they might be controlling the transition from deterministic to random.
Bloch response of framed wings with upper and lower skins.
Authors: Martinez R. , Eash M.
Published: March 2010

Aircraft wings are typically composed of spanwise-periodic framing elements running from leading to trailing edge. Each frame is connected to the wing’s upper and lower skins through continuity of motions among frames and skins. This paper presents calculations of a generic wing’s low-wavenumber Bloch response in global flexure per the following physical content: (1) the frames are mass controlled both in vertical translation and rotation; (2) the skins are plate-like, and respond dynamically to normal and compressional shears against each of the frames; (3) the two plates bend symmetrically with respect to the normal component of the virtual foces driving them, and antisymmetrically in compression with respect to their tangent component. The need for compressional forces and a corresponding in-plane response for each of the wing’s two skins stems from the theory’s lack of restrictions on frame height, which for our thick wing implies a neutral axis for global flexure that is far from the system’s uppermost and lowermost material points. Our calculations showcase the effects of the skins’ compression on the system’s low-wavenumber response, as well as how compression defines the structure’s low-frequency limit for a stiffness-controlled effective medium rendered anisotropic by its chordwise-running frames.
Control algorithms for adaptive time-frequency test signal synthesis for architectural acoustics measurements during music concerts.
Authors: Ren Gang , Lundberg Justin , Headlam Dave , Bocko Mark F.
Published: March 2010

A system was proposed by G. Ren et al. [158th Meeting of the ASA (2009)] to perform field acoustics measurements during ongoing music concerts. It addresses the long-standing problem of performing architectural acoustic measurements with an audience present. In this system, an adaptive time-frequency synthesis algorithm was employed to generate test signals with time-frequency energy distributions that conform to predicted “masked measurement vacancies” to ensure that the acoustic response of the test signals can be separated from the music and that the test signals are inaudible to the audience by taking advantage of auditory masking phenomena. In the present paper, approaches utilizing higher-level structure of music are exploited to reduce the number of conflicts between the test signals and the music. Three approaches are described: a music theory based probabilistic prediction algorithm, using prior knowledge of the score, and the third exploits the availability of previous recordings of the music being performed. These control algorithms are adapted to architectural acoustic measurement procedures conforming to ISO3382-1/2(2009). The proposed system achieves similar performance compare to conventional acoustic test procedures, which emit loud test signals in empty music halls.
An improved formulation for predicting low-frequency noise transmitted through double-pane windows.
Authors: Ou Dayi , Mak Cheuk Ming , Li Kai Ming
Published: March 2010

With superior sound insulation properties over a single-panel configuration, a double-panel structure with the presence of a cavity has found a wide range of applications for sound insulation. A classical method for combining a finite element method (FEM) with a boundary element method (BEM) is used to examine the transmission of low-frequency noise through double-pane windows in the present study. The technique of component mode synthesis is applied to adjust the stiffness matrix in the FEM formulation in order to examine the effects of elastic boundary conditions on the sound transmission through these structures. However, the Green function for predicting sound propagation in a rectangular long enclosure is used in favor of the free-field Green function for predicting the pressure inside the cavity of the window panes. The predicted pressure in the cavity is then coupled with the FEM formulation for the window panes and the BEM formulations for the sound fields at the outer surfaces of window panes. A parametric study is conducted systematically to allow a detailed examination for the characteristics of sound insulation of a double-pane window at different frequency bands especially for the low-frequency components.
Acoustic signatures of partial electric discharges in different thicknesses of Kapton.
Authors: Hanley Daniel P. , Tucholski Edward J.
Published: March 2010

Thin polymer films in the presence of high electric fields undergo partial discharge and have characteristic acoustic emissions. It is hoped that studying these acoustic signals can aid in anticipating failure of the films, thereby providing a tripwire to reduce the electric voltage in high-energy capacitor applications before failure actually occurs and the capacitor is permanently damaged. This study compared the acoustic emission from a variety of thicknesses of Kapton film between 7 and 55 μm. A laser Doppler vibrometer with a frequency response from 0–22 kHz was used to study surface vibrations of a gold coated polymer sample as voltage was raised at a controlled rate of 500 V/s from 0 V to material failure. Emissions from partial discharges prior to failure are studied. The results of these tests demonstrate the relationship between characteristic frequencies for the acoustic emission and the polymer thickness.
Seismic surface wave method for near surface soil exploration.
Authors: Lu Zhiqu
Published: March 2010

There are many applications that require the information of near surface soil properties. The related areas include agricultural land management, levee/dam evaluation, landmines/UXO/tunnel detection, battle field condition assessment, and site foundation characterization, to name a few. To obtain soil properties in a non-invasive manner, a multi-channel analysis of surface wave (MASW) method based on laser-Doppler vibrometer was developed recently and reported in 157th ASA Meeting, Portland, OR. This talk will present the latest development. In particular, two methods of determination of the dispersive curve, i.e., the phase slope method and the two dimensional FFT transformation method, will be discussed. The emphasis will be given to demonstrate the capabilities of the two methods in identifying the fundamental mode and high modes of Rayleigh waves. An inversion algorithm using the measured dispersive curve can back calculate the soil profile, i.e., the shear wave velocity as a function of depth. Several case studies of the MASW method will be addressed.
Fault classification for rotating machines using neural network.
Authors: Han Hyungseob , Chong Uipil
Published: March 2010

When the rotating machines in the plants malfunction during operating, they can cause huge economic losses and many casualties. For these reasons, fault detection and diagnosis of rotating machines have become very important issues. This paper proposes a system to detect and diagnose abnormal states for induction motors. Through an effective combination of wavelet transform and neural network for measured vibration signals from the motors, successful fault detection and diagnosis can be achieved. This system is divided into two parts: analysis and classification. In the analysis part, vibration signals are divided into eight subbands by using wavelet transform. The most significant features of the signals are shown in the lowest-frequency band. For an efficient classification in the neural network, input samples chosen in that band were minimized. In the classification part, through one of the representative techniques, multi-layer perceptron, all kinds of vibration signals are trained and tested. From the experimental results, the proposed system perfectly classified input signals into each fault case. Furthermore, since it does not need reference data for classification, it can perform very quickly and be implemented to a real-time system.
Common voice measures as indicators of fatigue.
Authors: LaJambe Cynthia M. , Brown Frederick M. , Reichardt Rebecca M. , Brenner Malcolm , Prosek Robert A.
Published: March 2010

Unobtrusive, economical, and readily accessible fatigue-monitoring technologies are needed especially in transportation, military operations, and security industries. Voice analysis is compatible with operational settings, given its minimal interference with hands-on work duties. Controlled laboratory studies are underway to establish the sensitivity of this fatigue-monitoring method. A recent study evaluated sleep-deprivation consequences on basic voice attributes using multiple speech tasks. Twenty-six native English-speaking 18-26 year-old subjects were screened for physical and psychological problems. Several sleep/wake cycles were monitored with actigraphy prior to laboratory participation. Vocal measures were compared between 13 speakers sleep deprived for 36 hours and 13 non-sleep-deprived controls. In the laboratory, speech was recorded during baseline sessions and on the following day. Group differences varied by speech task and vocal measure, with more sleep-deprivation sensitivity found, for example, in speaking rate as compared to fundamental frequency. Fatigue-related changes in vocal measures were associated with decrements in psychomotor reaction times and cognitive performance. Results are compared with previous studies relating psycho-physiological states to basic voice measures. Design considerations are discussed.
Speaker assessment: The impact of environment on speech systems and individuals.
Authors: Hansen John H. L.
Published: March 2010

Assessing speaker variability is critical in developing a scientific understanding or model of human speech production. The environmental context plays a significant role in how this variability plays out. In this study, recent findings are presented on the variability of speech production due to environmental factors that influence man-machine interaction as well as human-to-human interaction. Speech produced under task stress, emotional stress, and background noise (resulting in Lombard effect) all cause speech production changes. This impacts both speech processing algorithms intended for speech recognition/technology and human-to-human interaction. Specifically, two speech production domains are briefly considered including Part-1: speech production under varying types/levels of background noise and how this produces flavors of Lombard effect and impacts speaker recognition systems, and Part-2: assessing the stress/emotional state of parents/care-givers in quantifying the language learning exposure of children (ages 10–36 months). In Part-1: the UT-Scope corpus is employed with speech from 30 subjects (19M,11F) for analysis of duration and spectral tilt as well as developing an automatic Lombard effect classification scheme which is incorporated into speaker recognition. Next, Part-2: considers how neutral versus stressed/emotional state of adults impacts conversational turns and adult word-count in a child language learning environment (20 child-parent interactions).
Intelligibility of speech produced under sleep-deprivation conditions.
Authors: Boyce Suzanne , MacAuslan Joel , Combs Sandra , Blood Alexandra
Published: March 2010

In previous work, we applied the technique of acoustic landmark detection to speech produced under rested vs sleep-deprived conditions. We found significant differences for both the number and pattern of landmarks detected. In a parallel study we found significant differences in clear vs conversational styles of speech. While it has been shown by a number of investigators that clear and conversational speech styles differ in the degree to which intelligibility to listeners is preserved in noise, it is not clear whether the articulatory changes found in sleep-deprived speech affect the ability of listeners to understand what is said, especially in noise. In this paper, we present the results of a study in which normal-hearing listeners are asked to transcribe speech presented with and without background noise. Similar levels of background noise have been shown to reduce speech intelligibility for clear vs conversational speech presented to normal listeners. The speech in this study was produced under rested and sleep-deprived conditions. Results will be compared to effects of clear vs conversational speech presented in noise and in quiet.
The detection of stress, emotion, and deception from speech: The intersection of phonetics, policy, and politics.
Authors: Harnsberger James
Published: March 2010

While prior research on the detection of stress, emotion, and deception from speech and language has shown limited progress, this has not prevented the marketing of commercial devices that purport to detect these states to a variety of customers, such as law enforcement agencies, the military, intelligence agencies, homeland security, and insurance companies. For the major products currently on the market, all independent studies to date have failed to verify their efficacy with a wide range of speech materials collected under various experimental conditions, ranging from laboratory studies with carefully controlled speech to “mock crimes” to speech produced under realistic levels of jeopardy. This literature (including two studies by the author) will be reviewed and discussed in terms of how their experimental design and results are shaped and used in policy debates by private manufacturers, elected officials and their staffers, academic researchers, and others.
Using temporal cycles in spontaneous speech to quantify linguistic impairments in patients with neurodegenerative disorders.
Authors: Kaiser Eden , Pakhomov Serguei V. S. , Birnbaum Angela K. , Boley Daniel , Knopman David S.
Published: March 2010

Fronto-temporal lobar degeneration (FTLD) is a form of dementia which may manifest through symptoms similar to Alzheimer’s, including language-specific impairment. Linguistic manifestations of the disorder are often described in subjective assessments of the disorder, but not always easily quantifiable using objective tests. This paper investigates a speech characteristic not yet assessed in FTLD patients, that of “temporal cycles” [Henderson et al. (1966); Butterworth and Goldman-Eisler (1979)]. Temporal cycles in the speech of healthy adults consist of alternating and roughly equal periods of fluent and hesitant speech [Roberts and Kirsner (2000)]. A time series analysis of temporal cycles was conducted using spontaneous speech from 45 adults diagnosed with FTLD. Patients’ cognitive functioning was assessed using the language-specific clinical dementia rating (CDR) scale by board-certified neurologists. Periodicity of temporal cycles was quantified using the proportion of the energy in the highest peak to the total energy in the power spectrum. It was found that this measure was correlated with independent CDR assessments. The results of this study indicate that temporal cycles may be used to characterize the effects of neurodegenerative disorders on speech communication. [Work supported by US NIA Grants Nos. R01-AG023195, P50-AG16574, P30-AG19610, and NIH NIA-1R01AG026390, and Univ. of MN Academic Health Center.]
Transition characteristics in speakers with dysarthria and in healthy controls: Part IV: Additional data on vital capacity transitions and stroke patients.
Authors: Weismer Gary , Kuo Christina , Allen Phoebe
Published: March 2010

Formant transitions are known to provide important cues for speech perception, sound identification, and inferences to articulatory behavior. This study describes and examines three types of formant transitions [consonant-vowel (CV), vowel-consonant (VC), and diphthong transitions] in four groups of speakers: healthy, ALS, Parkinson’s disease, and stroke. This is an extension from previous work by Weismer et al. [J. Acoust. Soc. Am. 121, 3135 (2007)] and Weismer et al. [J. Acoust. Soc. Am. 124, 2558 (2008)], who showed shallower slopes for CV and diphthong transitions in persons with dysarthria (ALS and PD). To better understand the characteristics of the different transition types in healthy and disordered populations, two questions are addressed here. First, are CV transitions associated with dysarthria different from those in healthy speakers in a way comparable to the observed differences in diphthong transitions? Second, do VC transitions show the same normal characteristics, and are the differences between healthy speakers and speakers with dysarthria the same as in CV transitions? Distributional analyses for 50-ms CV, 50-ms VC, and diphthong (highest-lowest/lowest-highest) F2 transition measures will be presented for 18 healthy speakers, 4 speakers with ALS, 4 speakers with PD, and 20 stroke patients. [Work supported by NIDCD R01 DC003723.]
The differential effect of altered auditory feedback on speech in early- and late-onset of Parkinson disease.
Authors: Wang Emily Q. , Verhagen Metman Leo
Published: March 2010

Advanced speech symptoms in Parkinson disease (PD), such as “festinating speech” or palilalia and frequent hesitations, are a clinical challenge. This report is a part of a larger study testing the hypothesis that the use of altered auditory feedback (AAF) would improve speech intelligibility in patients with PD and more advanced speech impairment. Our initial report showed that the use of AAF indeed improved speech intelligibility in these patient’s spontaneous speech [Wang et al. (2008)]. In this report, the spontaneous speech samples produced by four older-onset (aged 72.4 SD 6.02 years) vs four young-onset PD patients (aged 54.2 SD 4.44 years), with and without the use of AAF, were analyzed. The results indicated that, regardless of the use of AAF, the older-onset patients performed poorer than the young-onset patients in many areas including the mean length of utterance in words, number of different word roots, within utterance pause time, and words per minute. These findings are consistent with the report that patients with an older age at onset had more rapid progression of PD than those with a younger age at onset in mentation, freezing, and activities of daily living. Possible underlying mechanism for the findings will be discussed.
Temporal analysis of simultaneous nasopharyngoscopic and nasometric recordings.
Authors: Tian Wei
Published: March 2010

The velopharyngeal port closes and opens by the velar and pharyngeal wall motion during speech. Velopharyngeal dysfunction (failure to close or open appropriately) often involves insufficient motion or mistiming of the motion. Despite the fact that evaluation of the velopharyngeal port size by nasopharyngoscopy has been popular in clinical settings, the temporal pattern of velar and pharyngeal motion has never been studied. On the other hand, separate nasal and oral recording of speech acoustics with a Nasometer is reported to demonstrate speech nasality change in customized utterances. The present study aimed at investigating the correlations between velopharyngeal motion and speech acoustic change by simultaneous recordings of nasopharyngoscopy and nasometry. Kymographic analysis of the motion in the velum and lateral pharyngeal walls were performed in two female adult speakers during five repetitions of six VCVNVCV at a controlled speech rate. Although the velar and pharyngeal motions show the similar pattern, they do not initiate and end simultaneously. There is strong correlation between the physiologic motion and acoustic change, but they are not synchronized and have very different temporal patterns. There is also difference across speakers and phonemes.
Bayesian parameter estimation in adaptive psychometric procedures: Simulated and experimental results.
Authors: Remus Jeremiah J. , Collins Leslie M.
Published: March 2010

The wide use of psychometric assessments and the associated time required to conduct such experiments have motivated a substantial research effort focused on developing more efficient psychometric procedures to expedite the estimation of parameters of interest. Adaptive step size psychometric procedures, which have increasingly received attention as an alternative to fixed step size procedures, can be viewed as having two separate stages: estimation of the parameters of interest based on the available data and a selection of the experimental settings in order to maximize the information obtained from the next trial. Psychometric procedures that utilize a Bayesian framework for parameter estimation have become more prevalent in recent years. In this talk, we will present experimental results for Bayesian psychometric procedures from both psychoacoustics studies and computer simulations. Several computer simulations explored the sensitivity of the procedure to different model parametrizations and evaluated performance using stimulus selection rules based on minimizing entropy and maximizing information gain. Psychoacoustic studies using two different listening tasks were used to investigate the robustness and stability of estimates provided by the Bayesian parameter estimation procedure. Collectively, the outcomes suggest that a Bayesian framework may be an important component in the development of more efficient psychometric procedures.
Revit and the role of architectural acoustics in the design process.
Authors: Larrick Jeff
Published: March 2010

A presentation by Autodesk discussing the role of Revit in the building information modeling design process and how it allows for collaboration between the architect and acoustical consultant.
Distilling the acoustical model from BIM (Building Information Modeling) Standard architectural, mechanical and structural models: Robust acoustical templates, limitations, and recommendations.
Authors: Vedvik Richard A. , Mooney Jon W.
Published: March 2010

The integration of architectural acoustics into building integration modeling (BIM) software and the implementation of such integration is discussed between available systems and platforms. The process of integrating the various platforms of building integration modeling software, in such a manner that the assigned properties can be shared, manipulated, and exported, is of great interest to acousticians. As the architectural model is created, a standardization of materials and generic construction methods is desirable so the relevant properties assigned to the various building components are able to be imported and adjusted by robust acoustical templates (RATs). Additional complications are identified as the acoustical model is detached from the live model. Standardization is also important between the architectural, structural, and mechanical models in order to create a common shared model that is able to maintain the relevant properties, both physical and analytical. Finally, the operation of a RAT prototype is demonstrated in the distillation of an acoustical model from standard BIM architectural, mechanical, and structural models.
Examining the relationship between total acoustic absorption and late lateral energy (GLL).
Authors: Dick David A. , Vigeant Michelle C.
Published: March 2010

Listener envelopment, the sense of being immersed in the sound field, has been shown to correlate with the objective parameter late lateral energy (GLL). Barron proposed that GLL is primarily a function of the ratio of reverberation time to auditorium volume or the total acoustic absorption [Barron, Appl. Acoust. 62, 185–202 (2001)]. An investigation has been conducted to examine this proposed theory with measurement data and predicted values from a room acoustics computer modeling program. Room impulse response measurements have been taken in the Belding Theatre in downtown Hartford, CT. Features of the hall include variable absorption in the form of curtains, both within the hall and also within small adjacent coupled volumes. Measurements were taken in several absorption configurations. A detailed room acoustics computer model of the hall has been created in ODEON v9.22 to examine the accuracy of the model’s prediction of GLL. The model was initially validated using the measured parameters of reverberation time (T30), early decay time (EDT), and clarity index (C80). A comparison of the measured and predicted results will be discussed, along with an analysis of the relationship between GLL and total acoustic absorption. [Work supported by a University of Hartford Greenberg Junior Faculty Grant.]
Experimental validations of the transport equation model for room-acoustic predictions in long spaces.
Authors: Jing Yun , Xiang Ning
Published: March 2010

This paper presents an experimental study on steady-state sound pressure levels and reverberation times in a tenth long-space scale model. The purpose of this work is to validate a recently developed one-dimensional transport equation model for acoustic predictions in long spaces. A series of measurements has been conducted in the scale model to reveal receiver-position dependence of measured and modeled parameters in the long spaces. Experimental results at different octave bands are obtained. This paper will compare the acoustically measured results with that of simulations.
Insertion loss estimation of an opened enclosure using a statistical ray-tracing model.
Authors: Xu Buye , Sommerfeldt Scott D. , Leishman Timothy W.
Published: March 2010

Estimating the insertion loss (IL) of an enclosure with one or more openings is important for many noise control applications. In the low-frequency range (below the Schroeder frequency) where modal effects are dominant, numerical simulations based on modal expansions or the finite element method are feasible for obtaining the desired predictions. Above the Schroeder frequency, statistical room acoustics theories are more desirable because numerical simulations are not applicable or are computationally expensive. However, existing room acoustics theories can only deal with simple cases where a diffuse field can be assumed. The acoustic field inside enclosures is generally sufficiently complicated in practice such that the diffuse field assumption is not valid. Examples of the complex conditions include narrow spatial regions, non-uniform boundaries, and the existence of obstacles in the enclosure. In this paper, a model that adopts the basic ideas of both ray-tracing and Sabine’s room acoustics theory will be introduced to deal with the difficulties mentioned. This new model greatly improves the ability to estimate acoustic performance when the enclosure conditions are not ideal, yet requires much less computation than the normal ray-tracing model. Comparisons of different models with experimental data will be presented.
High-resolution absorption mapping with a pu surface impedance method.
Authors: Tijs Emiel
Published: March 2010

The in situ method to measure the surface impedance with a pu probe documented is published in many publications. The method is based on the measurement of sound pressure (p) and particle velocity (u) close to an acoustic absorbing material. A loudspeaker at a defined distance is applied to generate a sound field with a known radiation impedance. The impedance of a small area (a few square cm2) with a known impedance is scanned with an ultraminiature pu probe very close to the surface. The area is made of steel with a cut-out, behind this a material with a known impedance is placed. In this paper the method is explained, the spatial accuracy of the measurement is examined, and a visualization technique is presented with a display of the spatial distribution (two dimensional picture) of the damping properties as function of frequency. Finally the high-resolution measurements are combined and compared with a method that covers a larger surface area.
Is it 6 decibels? The effect of pressure doubling on exterior to interior transmission loss values.
Authors: Hart Noel , Lefkowitz Kimberly , Bommer Arno S. , Bruce Robert D.
Published: March 2010

When calculating sound levels inside a building due to external sources, should some value be added to the expected sound level? ATSM E966 recommends adding 6 dB to this level. It has been theorized that this is due to pressure doubling. The effect of pressure doubling on the calculated exterior to interior sound transmission in the direct field is, however, often misunderstood. Most texts on the subject simply list a 5- or 6-dB correction factor that is applied to the transmission loss value. The reasoning of this particular number is neither expounded upon nor explained. This paper investigates and explains this correction factor.
Multipath features as a contextual clue for classification.
Authors: Tiemann Christopher O.
Published: March 2010

A single odontocete click is often heard as multiple click echoes due to the many paths sound travels between the source (whale) and receiver; these echoes are called multipath arrivals, and together they form an arrival pattern. Because each arrival can appear differently due to propagation effects, efforts to associate recorded clicks with individual whales can be frustrated by the presence of multipath arrivals, particularly when many whales click simultaneously. Automated classifiers may associate arrivals from one click event into many groups, even though they come from one source, thus overestimating the number of whales in a recording. However, collectively a multipath arrival pattern can be exploited to huge advantage when trying to do individual association. Typically, the relative spacing of arrivals changes slowly over time (due to slow movement of the source) and is unique for a given source location. The persistence of stable arrival patterns over successive click events provides a contextual clue for associating many arrivals to a single individual or can validate automated classification techniques. Finding unique arrival patterns should provide an accurate estimation of the number of sources in an area and even serves as the first step in passive acoustic tracking of whales.
Contextual rhythmic analysis of beaked whale clicks for passive acoustic identification.
Authors: Sidorovskaia Natalia , Schexnayder Philip , Ioup George E. , Ioup Juliette W. , Tiemann Christopher O. , Ekimov Alexander E. , Sabatier James
Published: March 2010

The Littoral Acoustic Demonstration Center (LADC) has collected an extensive acoustic library of marine mammal phonations in the Northern Gulf of Mexico, including the Cuvier’s and Blainville’s beaked whale clicks. An automatic algorithm, which performs cadence frequency analysis, has been developed and successfully applied to sperm whale clicks to identify temporal evolution of individual rhythmic patterns in overlapping trains of simultaneously clicking whales in a group. In this study the results of the association of cadence frequencies with individual beaked whales in a group for the LADC 2007 Gulf of Mexico recordings are reported. The algorithm is a part of an integrated tool proposed by LADC for identification of individual animals in a group. The cadence frequency association results are compared to multi-attribute self-organizing map clustering and to time-of-arrival analysis and localization. A multi-band version of the algorithm is also presented. It provides species association cues for complex cluttered acoustic environments where different species phonate with similar inter-click intervals. The proposed approach is beneficial for passive acoustic studies of beaked whale populations and social behavior and may contribute to understanding acoustic communication of these evasive animals. [Research supported by ONR and SPAWAR.]
Using click change detection to modify cluster analysis for acoustically identifying individual sperm whales with changing aspect.
Authors: Ioup George E. , Ioup Juliette W. , Pflug Lisa A. , Tiemann Christopher O. , Sidorovskaia Natalia A.
Published: March 2010

As described by Mohl et al. J. Acoust. Soc. Am. 114, 1143–1154 (2003)], the acoustic properties of the received clicks of a turning sperm whale change as the whale rotates. These changing properties (the time signal, the discrete Fourier transform, and the discrete wavelet transform are studied here) confound cluster analysis attempts to identify individual whales by grouping like clicks in classes representing individuals. The 4th International Workshop on Detection, Classification and Localization of Marine Mammals Using Passive Acoustics has associated workshop data containing a sequence of sperm whale clicks which most likely come from the same individual (as shown by careful manual click analysis) turning with respect to the acoustic recording buoy. The time domain sequence of clicks indicates that the angle of a line from the head of the whale to the buoy appears to be changing from greater than 90 deg to less than 90 deg and back again. Time evolution and click change detection are applied to follow the whale and give correct automatic identification. This analysis is incorporated into the clustering process. [Research supported by ONR and SPAWAR.]
Acoustic identification of individual beaked whales using self-organizing maps for automated classification of clicks in Littoral Acoustic Demonstration Center (LADC) data.
Authors: Ioup Juliette W. , Ioup George E. , Pflug Lisa A. , Sidorovskaia Natalia A. , Schexnayder Philip , Tiemann Christopher O. , Bernstein Alan
Published: March 2010

The Littoral Acoustic Demonstration Center (LADC) acquired underwater acoustic data from clicking sperm and beaked whales in the Gulf of Mexico during an experiment in July 2007. Analysis of sperm whale echolocation and coda clicks in the data has been presented at previous ASA meetings. Research emphasis is now on identifying individual beaked whales from their echolocation clicks. Again, clustering methods present one appropriate approach to the automated identification of these whales by computer. Self-organizing maps have the ability to limit the number of clusters automatically, and their successful use with sperm whales encourages the application to beaked whales as well. Results for time, frequency, and wavelet domain data allow comparison among clustering done using different signal representations and help highlight areas of concern in the analysis. As in the case of sperm whales, the beaked whale identifications are verified by comparing to cadence analysis (as presented in an accompanying abstract) and to a limited extent by manual analysis and localization. [Research supported by ONR and SPAWAR.]
Automated detection of sperm whales (Physeter macrocephalus) creaks and association with depredation events.
Authors: Mathias Delphine , Thode Aaron , Straley Jan , Calambokidis John , Schorr Gregory S. , Burgess Bill
Published: March 2010

Sperm whales have been depredating black cod (Anoplopoma fimbria) from demersal longlines in the Gulf of Alaska for decades, but the behavior has now become pervasive enough that it is starting to affect government estimates of the sustainable catch, motivating further studies of this behavior. In July 2007 and June 2009, bioacoustic tags were attached to adult sperm whales off Southeast Alaska under both natural foraging conditions and situations wherein the animals were depredating sablefish from commercial longlining vessels. Tags remained attached for a cumulative hours, yielding more than 100 h of depth, orientation, and acoustic data. Results show that when depredating, sperm whales often dive at depths shallower than 50 m, compared to natural foraging depths of 300–400 m in the area. Dive durations, pitch, and roll rates are also distinctively different. Techniques such as spectrogram cross-correlation and cepstral analysis are used to automatically detect creak events, which have lower intensities and narrower frequency ranges than conventional clicks. Acoustic measurements such as creak production rate, duration, and intensity are then extracted. Correlations are derived between creak events, sudden changes in body orientation and depredation rate, with a goal of determining an acoustic measure of depredation activity and efficacy. [Work conducted under the SEA SWAP Program, supported by the North Pacific Research Board and the National Geographic Society.]
Quantitative ultrasound in the management of osteoporosis.
Authors: Krieg Marc-Antoine , Didier Hans
Published: March 2010

Bone mineral density (BMD) is one of the major determinants of bone strength and fracture risk (FR), but it is not the only determinant, and overlap exists in BMD values between patients with and without fractures. It is therefore important to improve the strategy in better detecting patients at high FR who will benefit from treatments (TT). Quantitative bone US(QUS) are portable and less expensive than DXA. Only few QUS measuring the heel have reached a sufficient level of validation to be routinely used. They usually measure the attenuation (BUA) and the velocity (SOS) of the US wave. It is well established that valid heel QUSs predict fragility fracture in PM women and men >65, independent of BMD. Then, heel QUS can be used in combination with other clinical risk factors (CRFs) in a model of risk assessment. Then, when DXA is available, the primary clinical use of heel QUS is to identify, in conjunction with CRF, a population at low FR in which no further diagnostic evaluation is necessary. On the other hand, if central DXA cannot be done, pharmacologic TT can be initiated if the probability, as assessed by heel QUS in conjunction with CRF, is sufficiently high.
New developments in x-ray micro-computed tomography technology and its applications to study bone micro-architecture.
Authors: Kapadia Rasesh
Published: March 2010

Developments in hardware and software capabilities, along with a significant increase in access to equipment and awareness of the methods, over the last 10 years have enabled micro-computed tomography (CT) technology to establish itself as one of the basic tools to study bone micro-architecture in the laboratory. A wide range of equipment is now available ranging from synchrotron based facilities to compact desktop scanners for small to large specimens and scanners for in vivo pre-clinical imaging. The various scanners offer the ability to acquire images with resolution ranging from sub-micron to 100 μm in acceptable scan times and where applicable, with acceptable x-ray doses. More recently, high-resolution scanners (under 100 μm) have become available for clinical research. Micro-CT is now widely used to investigate bone from pre-clinical models of various aging and pathologic conditions (osteoporosis, osteoarthritis, and arthritis) as well as models for tissue regeneration and bone fracture repair as well as high-throughput skeletal phenotyping. Pre-clinical in vivo imaging methods are now routinely used as a screening tool in drug discovery and development processes. The availability of sophisticated software for analyses and visualization of these images has made micro-CT a very versatile research tool for the pre-clinical laboratory and promises to do the same for clinical research.
Comparison of conventional ultrasonic phase velocity and attenuation measurements of cancellous bone to estimates obtained using Bayesian probability theory.
Authors: Anderson Christian C. , Pakula Michal , Laugier Pascal , Bretthorst G. Larry , Holland Mark R. , Miller James G.
Published: March 2010

Cancellous bone supports the propagation of two compressional waves, commonly referred to as fast and slow waves, which can overlap in the acquired time-domain data. When such data are processed using conventional techniques, interference effects may cause artifacts to be present in the speed of sound and broadband ultrasound attenuation (BUA) measurements. Bayesian probability theory is a proposed method for extracting the ultrasonic properties of the individual fast and slow waves, even in the presence of substantial interference. In the current study, data were acquired in vitro at sites on a cancellous bone, and the acquired signals were used as input to a Bayesian probability approach for estimating parameters characterizing the fast and slow waves. For comparison, the signals were also processed using conventional methods. Although the conventionally obtained phase velocity and BUA frequently exhibited anomalous features, including negative dispersion, those estimated using probability theory exhibited no aberrant behavior. Hence, material properties obtained using Bayesian probability theory may provide more reliable estimates of bone quality and fracture risk than the apparent properties derived from the non-causal mixed mode signals. [Work supported by NIH R01HL40302 and R01AR057433, NSF CBET-0717830.]
Transfer functions for one-dimensional bone models.
Authors: Buchanan James L. , Gilbert Robert P. , Ou Miao-Jung
Published: March 2010

A system for calculating wave pulses through one-dimensional layered media via a series of transfer functions is developed. This system obviates the need for numerical approximation beyond the use of discrete Fourier transforms, whence it is not necessary to deal with the poor numerical conditioning of the linear systems that arise in multi-layered models. A one-dimensional model of bone as a cancellous segment between two cortical segments insonified by an ultrasonic pulse is considered. For the cancellous segment the Johnson–Dashen–Koplik modification of Biot’s model for a poroelastic medium is used. The cortical segments are modeled both as dense fluids or porous media and the results compared.
Fabric dependence of wave attenuation in anisotropic poroelastic media.
Authors: Cardoso Luis , Cowin Stephen
Published: March 2010

The governing equations for wave motion in the linear theory of anisotropic poroelastic materials have been developed and extended to include the dependence of the constitutive relations upon fabric. Fabric is a quantitative stereological measure of the degree of structural anisotropy in the pore architecture of a porous medium. This anisotropic poroelastic theory is then applied to cancellous bone architecture to study the role of both porosity and fabric on the wave attenuation due to reflection, absorption, and scattering. The analysis of the fast and slow wave attenuation is performed as a function of the porosity of the medium and the frequency of the wave. This study demonstrates that the attenuation ratio between fast and slow waves strongly depends on the porosity and fabric of the trabecular structure. Wave attenuation predictions from this model confirm our previous experimental observations indicating that either the fast or slow wave may be the predominant wave mode in trabecular bone depending on the bone architecture. [This work was supported by grants from NSF (NSF/CUNY AGEP 0450360, NSF-MRI 0723027, and PHY-0848491). The authors also acknowledge the support from PSC-CUNY Research Award Program (PSC-CUNY-60014-38-39, 69486-00 38, and PSCREG-39-1103) and NIH 1SC2AG34198-1A1.]
Fabric dependence of tortuosity in poroelastic wave propagation.
Authors: Cowin Stephen , Cardoso Luis
Published: March 2010

The governing equations for wave motion in the linear theory of anisotropic poroelastic materials have been developed and extended to include the dependence of the constitutive relations on fabric. Fabric is a quantitative stereological measure of the degree of structural anisotropy in the pore architecture of a porous medium. With the addition of the second order symmetric tensor fabric variable, the formulation of wave motions in the poroelastic theory is consistent with the presentations of Biot and later authors. In this work we show that tortuosity is a function of the fabric tensor. This relationship between tortuosity and fabric is employed to provide a geometric understanding of tortuosity in terms of pore space architecture. This geometric understanding is then applied to cancellous bone architecture. [This work was supported by grants from NSF (NSF/CUNY AGEP 0450360, NSF-MRI 0723027, and PHY-0848491). The authors also acknowledge the support from PSC-CUNY Research Award Program (PSC-CUNY-60014-38-39, 69486-00 38, and PSCREG-39-1103), and NIH 1SC2AG34198-1A1.]