bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound speed and attenuation in the sea bottom from broadband sound propagation in the Yellow Sea.
Authors: Wan Lin , Zhou Ji-Xun , Rogers Peter
Published: October 2013

A joint China-U.S. underwater acoustics experiment was conducted in August, 1996 in 75-m water in the Yellow Sea with a very flat bottom and a strong and sharp thermocline. Broadband explosive sources were detonated both above and below the thermocline along two radial lines and a quarter of circle. Two inversion schemes are used to obtain the sound speed in the bottom. The first scheme is based on extracting normal mode depth functions from the cross-spectral density matrix (CSDM). The CSDM is constructed from explosive signals measured using a 32-element vertical line array at a fixed long range. In the second scheme, the modal arrival times are extracted using an adaptive time-frequency analysis technique. The inverted bottom sound speed is used as a constraint on high-quality TL data to extract the bottom sound attenuation. The inverted bottom attenuation exhibits apparent nonlinear frequency dependence over a frequency range from 80 to 1260 Hz. A possible effect of mode-coupling on the inverted bottom attenuation is discussed. Measured TL as a function of frequency, range, and depth is in good agreement with the predictions based on the inverted bottom acoustic parameters. [Work supported by ONR.]
Measuring grain roughness for the purpose of high-frequency acoustic modeling.
Authors: Briggs Kevin , Reed Allen , Ray Richard , Richardson Michael
Published: October 2013

Grain roughness and packing are important sediment properties for newer acoustic models. We present the scanning electron stereomicroscopic imagery of natural sand grains of varying shape and roughness for evaluation of potential grain interactions of individual grains. The grain shape and the presence of microasperities will determine the probability of the contact with surrounding grains being a point or a larger area. Moreover, the use of a micro-roughness power spectrum in characterizing the sand grain roughness may be appropriate. Grain contact information is an essential starting point for developing and evaluating acoustic models that address acoustic losses at high frequencies. This information provides the basis to understand contact mechanics, such as grain slip and frame dilation, during insonification. Because media frame stiffness depends, at the grain scale, on the number and type of grain-to-grain contacts, we characterize sand sediments with imagery identifying such grain contact information. The natural shapes of grains, their variations, and their packing density present a broad distribution of grain contact types and areas. X-ray microfocus computed tomography captures volumetric images of grain interactions, which enable the grain contacts to be classified and quantified. The method and results of this evaluation with computed tomography will be also presented.
Dynamic encoding of pitch, timing, and timbre.
Authors: Kraus Nina
Published: October 2013

The perception of music depends on three fundamental elements: pitch, timing, and timbre. It is possible to access the neural transcription of these elements objectively, noninvasively, and with great fidelity with scalp electrodes in humans. The effects of musical experience on subcortical encoding of sound are pervasive and extend beyond music to the domains of language and emotion. The acoustic cues relating to pitch, timing, and timbre have distinct representations, which can be selectively enhanced or degraded in different populations. Musically trained subjects have enhanced subcortical representation of pitch, timing, and timbre, although with increased stimulus complexity, timbre cues become more pronounced while pitch cues are diminished. Musical experience fundamentally shapes auditory processing that occurs early in the sensory processing stream. This top-down influence is likely mediated by the extensive (corticofugal) circuitry of descending efferent fibers that synapse all along the auditory pathway. Sensory shaping occurs not only with lifelong experience but can be effected by short-term training. I will discuss a series of experiments demonstrating the lifelong and short-term malleability of the neural encoding of pitch, timing, and timbre in the auditory brainstem. [Work supported by National Institutes of Health (R01DC001510) and National Science Foundation (NSF 0544846).
Nonlinear dynamics approach to pitch perception and harmony.
Authors: Cartwright Julyan H. E. , Gonzalez Diego L. , Piro Oreste
Published: October 2013

For perception, the brain handles and reacts to an enormous amount of information from the senses in real time. The question of how all this information is represented and processed within the nervous system is addressed by the nonlinear and complex system researches through the proposal that dynamical attractors may form the basis of neural information processing. Sometimes, this rather qualitative approach to modeling provides very accurate quantitative predictions. Here we show an example where this idea can be successfully applied in the human auditory system to describe and, perhaps, explain the nature of some phenomena in the perception of pitch. We will also discuss possible implications of this approach to the theory of harmony.
Coding for underwater acoustic channels.
Authors: Zhou Shengli
Published: October 2013

This talk will give an overview on channel coding, coded modulation, and their applications in underwater acoustic channels. We will cover classical block codes, convolutional codes, and the traditional coded modulation such as trellis coded modulation and bit-interleaved-coded-modulation. We will then focus on modern Turbo codes and low-density-parity-check codes, space-time coding, and highlight the recent progress on the application of the iterative (or Turbo) principle to underwater acoustic communications.
Patterns of coastal use by Hawaiian spinner dolphins (Stenella longirostris) observed using passive acoustic monitoring.
Authors: Lammers Marc O. , Bernasconi Simona , Au Whitlow W. L. , Wong Kevin , Brainard Russell E.
Published: October 2013

Spinner dolphins are the most commonly sighted cetacean in coastal Hawaiian waters and are an important higher-level trophic component of the near-shore ecosystem. Establishing their long-term patterns of occurrence is important both for their conservation and for a better understanding of the relationships between dolphins, their prey, and other members of the ecosystem. Here we report on an effort to use ecological acoustic recorders (EARs) to monitor the presence of spinner dolphins along the leeward coast of the island of Oahu, Hawaii. The EAR is a bottom-moored recorder with a bandwidth of 30 kHz, which allows the detection of both dolphin whistles and echolocation clicks. Eight EARs were deployed along the coast at depths ranging from 15 to 50 m. Five units were deployed in an array, providing information about the EAR’s detection range. The other three units were placed at sites along the coast commonly frequented by spinner dolphins. The results reveal distinct patterns of preference in habitat use, both for daytime resting behavior and night-time foraging. The recordings also provide a measure of vessel traffic at locations important to spinner dolphins. Combined, these data demonstrate the value of passive acoustic methods for monitoring cetacean populations and their habitat over extended periods.
Contextual sound production by tagged humpback whales (Megaptera novaeangliae) on a feeding and breeding ground.
Authors: Stimpert Alison K. , Au Whitlow W. L. , Wiley David N. , Mattila David
Published: October 2013

Humpback whales are amongst the best studied of the baleen whales. The species is also known for its flexibility and variety of behavior on both feeding and breeding grounds. DTAGs were attached to 19 whales on the Hawaiian breeding grounds and to 24 whales on the northwestern Atlantic feeding grounds between the years of 2004 and 2008 to describe the variety of acoustic behavior in each location. Sounds were analyzed using ADOBE AUDITION, XBAT, and custom programs in MATLAB 7, and acoustic records from the tags showed differences in sound production between the two populations engaged in different activities. Recordings from the feeding grounds showed higher social sound production rates and also contained the sounds with the highest signal-to-noise ratios (10–20 dB for 1 μPa higher than on the breeding grounds). Differences in ambient noise may contribute to this: song chorusing is present in Hawaii, but commercial shipping traffic is higher in the northwest Atlantic feeding areas. Some similar sounds were recorded from the two areas, and exemplars of sound types from each location will be described. Overall, the feeding whales appeared to use sound more frequently, and perhaps for longer range communication than sounds produced within competitive groups in Hawaii.
Historical perspectives and ongoing developments in telematic performances.
Authors: Gresham-Lancaster Scot
Published: October 2013

This paper presents historical perspective on development 8232, and new technology applications for performances in which the author collaborated with several other dancers, musicians, and media artists to present synchronized colocated concerts at two or more sites. This work grew out of the author’s participation in the landmark computer music ensemble, “The HUB.” Each of the various performances was made possible by an evolving array of videoconferencing hardware and software. These will be discussed, as well a look back at the early history of “telematic” performance. The problems and interesting side effects presented by latency and dropouts are a unique part of this performance practice. This work leverages the concepts of shared space, and video and audio feedback generate with evolving forms created by the combinations of the space, the sounds, and the movements of the participants. The ubiquity of broadband Internet connections and the integration and constant improvement of videoconferencing software in modern operating systems make this unique mode of performance an essential area of research and development in new media performance. These new techniques will be discussed as well.
A filtered convolution method for the numerical evaluation of very large-scale ultrasound problems.
Authors: Verweij Martin , Huijssen Jacob , de Jong Nico
Published: October 2013

The pulsed ultrasound field in nonlinear biomedical tissue may be computed by the recurrent evaluation of the field of a distributed contrast source in a linear homogeneous background medium. For human organs, the computational domain may easily measure hundreds of wavelengths or periods in each spatiotemporal dimension. Even with today’s supercomputers, the evaluation of the transient field from the contrast sources in these very large inhomogeneous domains is a big challenge, and is only feasible if the applied numerical method is extremely efficient in terms of memory usage and computational speed. Using a Green’s function method, the critical operation is a spatiotemporal convolution over the entire computational domain. It is shown how a systematic filtering and windowing of the involved functions yield accurate numerical convolutions with a discretization approaching the Nyquist limit of two points per wavelength or period of the highest frequency. This minimizes the storage requirement. Application of fast Fourier transforms for evaluation of the discrete convolution sum renders a method that is also computationally fast. The performance of a Neumann method equipped with these numerical convolutions is shown by presenting the computed transient wave field that traverses a very large inhomogeneous domain. [Work supported by the STW and the NCF.]
Timbre perception.
Authors: Hennig Lydia
Published: October 2013

An electroencephalographic study dealing with timbre perception has been performed. Timbre is next to tone and chroma is the basic element of sound and is perceived as a multidimensional space in which perceptual coordinates correlate with acoustic parameters. To show these correlations and their associations with different brain areas, sounds all constant with respect to their fundamental pitch of 311 Hz were varied in timbre. Due to these variations of acoustical parameters clear differences could be found concerning the perceptional pathway and corresponding brain areas. The modification applied to the sounds included variations of attack time, spectral center of gravity, and even harmonic attenuation. Next to other findings a hierarchy of perception was found where variations of the attack time was overwritten by the even harmonic attenuation and the spectral centroit variations, but only if all three were varied simultaneously. In all other cases the attack time variations caused clear perceptional delays in the prefrontal lobe.
The relationship between open quotient and H1*-H2*.
Authors: Kreiman Jody , Iseli Markus , Neubauer Juergen , Shue Yen-Liang , Gerratt Bruce R. , Alwan Abeer
Published: October 2013

It is widely assumed that changes in open quotient (OQ) produce corresponding changes in H1*-H2*, but empirical data supporting this relationship are scant. To provide such data, high-speed video images and audio signals were simultaneously recorded from six speakers producing the vowel /i/ while varying F0 from high to low and voice quality from pressed to breathy. Across speakers, the observed relationship between OQ and H1*-H2* was much weaker than generally assumed. Patterns of covariation also differed substantially from speaker to speaker. Estimation of harmonic amplitudes was complicated by difficulties in determining the frequency of F1 when F0 was high and by uncertainties regarding the F1 bandwidth in the presence of a persistent glottal chink. Use of analysis-by-synthesis allowed correction of formant values, but bandwidth estimation remains problematic and will be discussed further at the conference. [Work supported by NIH Grant DC01797 and NSF Grant BCS-0720304.]
Alternatives to f0 turning points in American English intonation.
Authors: Barnes Jonathan , Veilleux Nanette , Brugos Alejna , Shattuck-Hufnagel Stefanie
Published: October 2013

Since the inception of the autosegmental-metrical approach to intonation (Bruce 1977, Pierrehumbert 1980, Ladd 1996), the location and scaling of f0 turning points have been used to characterize phonologically distinct f0 contours in various languages, including American English. This approach is undermined, however, by the difficulty listeners experience in perceiving differences in turning point location. Numerous studies have demonstrated either listener insensitivity to changes in turning point location or the capacity for other aspects of contour “shape” to override turning-point alignment for contour identification (Chen 2003, D’Imperio 2000, Niebuhr 2008). Even labelers with access to visual representations of the f0 encounter similar challenges. By contrast, a family of related measurements using area under the f0 curve to quantify differences in contour shape appear more robust. For example, a measure of the synchronization of the center of gravity of the accentual rise with the boundaries of the accented vowel yields 93.9% correct classification in a logistic regression model on a data set of 115 labeled utterances differing in pitch accent type. (L*+H L+H* in ToBI terminology). This classification proceeds entirely without explicit reference to the turning points (i.e., beginning of rise, peak) traditionally used to characterize this distinction.
Comparison of a child’s fundamental frequencies during structured and unstructured activities: A case study.
Authors: Hunter Eric
Published: October 2013

This case study investigates the difference between children’s fundamental frequency (F0) during structured and unstructured activities, building on the concept that task type influences F0 values. A healthy male child (67 months) was evaluated (31 h, 4 days). During all activities, a National Center for Voice and Speech voice dosimeter was worn to measure long-term unstructured vocal usage. Four structured tasks from previous F0 studies were also completed: (1) sustaining the vowel /ɑ/, (2) sustaining the vowel /ɑ/ embedded in a phrase-end word, (3) repeating a sentence, and (4) counting from one to ten. Mean F0 during vocal tasks (≈257 Hz), as measured by the dosimeter and acoustic analysis of microphone data, matched the literature’s average results for the child’s age. However, the child’s mean F0 during unstructured activities was significantly higher (376 Hz). The mode and median of the vocal tasks were respectively 260 and 259 Hz, while the dosimeter’s mode and median were 290 and 355 Hz. Results suggest that children produce significantly different voice patterns during clinical observations than in routine activities. Further, long-term F0 distribution is not normal, making statistical mean an invalid measure for such. F0 mode and median are suggested as two replacement parameters to convey basic information about F0 usage.
The weighting of vowel quality in perception of English lexical stress.
Authors: Zhang Yanhong , Francis Alexander
Published: October 2013

Acoustically, English lexical stress is multidimensional, involving F0, duration, intensity, and vowel quality. Previous research found that Mandarin speakers had problems using vowel reduction in English lexical stress production. Assuming nativelike perception is a prerequisite to nativelike production for non-native speech, the weight of vowel quality with comparison to that of F0, duration, and intensity in Mandarin listeners’ stress perception was examined. Mandarin and English listeners judged lexical stress placement in synthesized tokens of desert, in which the first syllable /de/ was varied along vowel quality and each of the other cues depending on the pair of cues in focus. Results showed that both Mandarin and English listeners consistently weighted vowel quality more than the other cues. Vowel quality and duration were treated as combinational cues by both groups. English listeners used both intensity and vowel quality (separately), while Mandarin listeners did not use intensity at all. Findings suggest that Mandarin listeners had a nativelike use of vowel quality for perceiving English stress. However, Mandarin listeners treated F0 in a different way from English listeners, possibly owing to the influence of their native tonal background. Implications for the interaction between production and perception in second-language learning will be also discussed. [Work supported by Purdue Linguistics.]
Effects of language background on tonal perception for young school-aged children.
Authors: Liu Chang , Yang Jie
Published: October 2013

Given that Chinese is a tonal language while English is not, the present study investigates how language background affects tonal perception for young children. Tonal identification and discrimination are measured on for three groups of school-aged children (6–7 years old): Chinese-monolingual (CM), English-monolingual (EM), and English-Chinese bilingual (ECB) children. Children’s task is to identify and discriminate tone 1 (level), tone 2 (rising), and tone 4 (falling) of a Chinese syllable /ma/, for which the fundamental frequency contour is systematically manipulated from tone 1 to tone 2 and from tone 1 to tone 4. CM and ECB children show typical categorical perception in both identification and discrimination, while EM children cannot identify and discriminate the three tones. These results suggest that learning and exposure experience of the tonal language is critical for children to perceive tonal changes in speech sounds.
Investigating the influence of context frequency on lexical tone perception.
Authors: Huang Jingyuan , Holt Lori
Published: October 2013

Tone languages such as Mandarin use pitch variations to contrast meaning. Within tone languages, large variability exists in the pitch of tones produced by different speakers. However, previous studies of speaker normalization for contour tones have produced inconsistent results; whether speakers rely on context information in tone perception is unclear. The present study intended to provide an unambiguous test of the effect of context on contour lexical tone perception and to explore its underlying mechanisms and sources of information. In four experiments, Mandarin listeners’ perceptions of Mandarin first and second (level and rising) tones were investigated with preceding speech and nonspeech contexts. Results indicate that (1) the mean fundamental frequency (f0) of a preceding sentence affects the perception of contour lexical tones and the effect is spectrally contrastive: Following a sentence with a higher-frequency mean f0, a following word is more likely to be perceived as a low-frequency tone and vice versa; (2) nonspeech precursors also elicit this effect, suggesting general perceptual rather than articulatory-based mechanisms; (3) listeners can use information from both fundamental frequency and periodicity to normalize tone perception. [Work supported by NIH NIDCD 2 R01DC004674-04A2].
A sparse-grid, nonintrusive formulation of acoustic field uncertainty in ocean waveguides.
Authors: Finette Steven , Burkhardt John
Published: October 2013

The inclusion of environmental uncertainty in simulations of acoustic wave propagation in ocean waveguides is important for the development of simulation-based prediction methods that quantify the influence of multiple sources of incomplete environmental knowledge on the simulation results. Polynomial chaos expansions have been suggested as a natural mathematical framework for describing both environmental and acoustic field uncertainties, their interaction, and propagation through the waveguide [S. Finette, J. Acoust. Soc. Am. 120 (2006)]. Previous research has described the inclusion of these expansions directly into the propagation equation (the intrusive approach), yielding coupled differential equations for the expansion coefficients. The solution for the coefficients contains the statistical properties of the uncertain field. Here we describe an alternative nonintrusive formulation, where existing acoustic propagation codes can be used to estimate the chaos coefficients rather than solve for them via a complex set of coupled differential equations. The nonintrusive formulation involves multiple solutions of an existing deterministic code, e.g., a wide-angle parabolic equation solver, in conjunction with the Smolyak sparse-grid interpolation and multidimensional quadrature to obtain uncertainty statistics on the acoustic field. [Research supported by the Office of Naval Research.]
Resolution matrix perturbation series applied to a nonlinear ocean acoustic inverse problem.
Authors: Odom Robert I. , Ganse Andrew A.
Published: October 2013

The resolution operator for a nonlinear inverse problem is the product of the estimated inverse of the forward model operator and the forward model operator itself. If the inverse of the forward model operator were exact, then the resolution operator would be the identity, but in general the resolution operator describes the (noninvertible) transfer function between the unknown true environmental model and the limited-resolution version, which can be estimated from measurements. The nonlinear model resolution operator can be computed iteratively from the Neumann series representation of an estimate of the inverse of the forward model operator with the assumption that both the data functional and the model perturbation functional possess regular perturbation expansions. An example of a problem that fits these criteria is normal mode acoustic propagation with “slow enough” perturbations such that the modes adjust adiabatically to the perturbations, and the mode eigenvalues are “far” from cutoff. We examine the effects of the nonlinear components of the model and the higher order components of the model resolution on the reconstruction of the model estimate for a simple ocean acoustic propagation problem. [Work supported by ONR.]
Open ocean seamount geoacoustic inversion.
Authors: Heaney Kevin D.
Published: October 2013

During the BASSEX-2004 (Basin Acoustic Seamount Scattering Experiment), sound from three sources [(250 Hz LFM, 100 Hz bandwidth) and (75 Hz, m-seq, 50 Hz bandwidth)] was transmitted in a range of 200–250 km to a moving towed array receiver (200 m aperture, cut for 250 Hz) in the vicinity of two seamounts in the central North Pacific. The seamounts rise from a depth of 6000 m to approximately 1000 m below the sea surface. A simple sediment model (soft surficial unconsolidated sediment overlying a hard basement) is used to try and model the energetics of the receptions. Two sets of receptions are used to perform this geoacoustic inversion. The first is a received energy versus range (equivalent to TL versus range) in the shadow behind the seamount. The depth of the received level minimum behind the seamount is sensitive to the sediment cover of the seamount. This approach is limited by the available signal-to-noise ratio at the receiver. The second approach is to use data taken when the receiver is just above the seamount. For this geometry, the beamformer is capable of resolving direct propagating paths and paths that bounce off the seamount up to the array from below.
My colleague and competitor: Russell Johnson.
Authors: Jaffe Christopher
Published: October 2013

This presentation documents the relationship between two architectural acoustic consultants that were active throughout the second half of the 20th century and into the 21st century. It illustrates the fact that practioners in a competive setting, devoted to the search for truth, can work together to arrive at solutions that enable a discipline to move forward.
Automated classification of frequency-modulated bowhead whale calls using contour tracing and image segmentation methods.
Authors: Mathias Delphine , Thode Aaron , Blackwell Susanna B. , Greene Charles R. , Kim Katherine H.
Published: October 2013

In 2007, directional autonomous seafloor acoustic recorders (DASARs) were deployed at 35 locations over a 280 km swath in the Beaufort Sea in order to monitor potential changes in bowhead whale (Balaena mysticetus) locations and/or acoustic activity during seismic exploration activities. The large amount of acoustic data generated motivated the development of computer-aided methods to assist in detecting and classifying bowhead whale calls. In the classification stage, bowhead whale calls were divided into six categories: (1) upsweeps, (2) downsweeps, (3) constant calls, (4) u-shaped and (5) n-shaped undulated calls, and (6) complex calls. The frequency range, duration, and fine structure of individual calls vary considerably, creating difficulties when using match-filtering or spectrogram correlation methods. A manually reviewed test data set was assembled, containing examples from each call category, arranged by signal-to-noise ratio. The data set was then used to test several methods (based on image segmentation techniques) for extracting relevant parameters from the signal for subsequent classification. An optimization procedure was then used to generate receiver operating characteristic curves and thus determine appropriate decision boundaries for optimum statistical classifiers. [Work supported by Shell Exploration and Production Company.]
Consistency of frequency dependent echolocation beam focus in an echolocating false killer whale (Pseudorca crassidens) performing a discrimination task.
Authors: Kloepper Laura , Ibsen Stuart , Nachtigall Paul , Breese Marlee
Published: October 2013

Tremendous variation in individual echolocation click parameters has been shown for odontocetes, making trend analysis of individual clicks within a click train necessary to understand their generalized echolocation behavior. The frequency dependent spatial echolocation beam profile of clicks for a single false killer whale (Pseudorca crassidens) performing a discrimination task was collected using a star shaped 16 hydrophone array. These spatial profiles were analyzed to compare the relative spatial location and focusing of various frequencies from click to click under different target exposures. Using a go/no go paradigm, the whale actively discriminated between objects of varying transmission reflectance properties. Very tight focusing and consistent spatial location was observed for frequencies near peak frequency but deteriorated for frequencies above peak frequency. This trend did not vary between targets, suggesting that the animal maintained a constant beam focus pattern regardless of the reflection characteristics of the target. Additionally, these patterns were consistent for all clicks within a train, suggesting that the animal employs a similar beam focus pattern throughout the entire click train.
Remote detection of vehicle obscured by forest canopy using laser Doppler vibrometer.
Authors: Sabatier James , Ekimov Alexander , Aranchuk Vyacheslav , Mack Richard
Published: October 2013

Detection and identification of vehicles obscured by forest canopy is a particularly challenging military problem. Imaging techniques (laser radar imaging a target through gaps in foliage, for example) require extensive data, making this approach processing-intensive and time consuming. A new method for detection of a vehicle obscured by forest canopy by remotely sensing the vibration of foliage with a laser Doppler vibrometer has been proposed. The method uses the effect of coupling of sound waves from the vehicle's engine through the air to tree leaves, causing them to vibrate. The presence of a vehicle can be determined by the spectrum of the leaves' vibrations. The feasibility of the proposed method has been studied experimentally. The acoustical impedance of various types of leaves was measured in the laboratory and outdoor settings. The results show that the vibration response of a leaf to the sound from an idling vehicle is high enough to be reliably sensed with an LDV in a wide frequency band. The vibrations of leaves excited with simulated vehicle acoustic stimuli were successfully measured with an LDV in the laboratory and outdoor environment. A real vehicle masked by foliage was successfully detected by the proposed method.
Modal analysis of musical instruments.
Authors: Rossing Thomas
Published: October 2013

The complex vibrations of musical instruments can be described in terms of normal modes of vibration. Modal analysis can be done either experimentally or mathematically. We review some of the ways in which modal analysis has been successfully applied to musical instruments in the string, wind, and percussion families.
Applying electronic speckle pattern interferometry to the study of musical instruments.
Authors: Moore Thomas
Published: October 2013

An overview of the electronic speckle pattern interferometer as a tool for the study of structural vibrations will be presented, highlighting both the theory and construction of the device. Two specific applications to the study of musical instruments will then be discussed: time-averaged interferometry of harmonic motion and time resolved interferometry of transient motion.
Generalized structural acoustics model of violin radiativity profiles.
Authors: Bissinger George
Published: October 2013

Violin radiativity profiles are dominated by contributions from the Helmholtz-like A0 cavity mode near 280 Hz, the first corpus bending (B1) modes near 500 Hz, followed by a slow rise, peaking near 2.4 kHz, and a slow falloff above this peak. A blend of total damping trends, f-hole air motions, bridge-filter effects, bridge versus bridge-island impedances, effective critical frequencies fcrit, and radiation efficiency-damping trends was used to create a structural acoustics model for the entire profile. The lowest top and back plate bending modes 2 and 5 subsumed into the B1 modes provide nominal values for the violin fcrit as well as significantly influencing the B1 mode frequencies. A0 excitation via coupling of f-hole volume flows with those of the B1 modes is proposed. This coupling predicts A0 radiativity increasing as the A0-B1 frequency difference decreases, in accord with recent VIOCADEAS data (including violin octet experimental results) and a 1937 experiment involving too-thick/too-thin plate thickness and soundpost removal. Simplified simulations show the fraction-of-vibrational-energy-radiated Frad peaking at fcrit (nominally coinciding with the bridge-filter peak). Dropping fcrit drops this peak frequency, reduces the maximum Frad, and changes the relative spectral balance in vibration-acoustic energy conversion.
Acoustic holography of musical instruments using radiation directivity method.
Authors: Bader Rolf
Published: October 2013

Static and time-dependent acoustic holography is applied to the radiation of musical instruments using the acoustic camera developed at the Institute of Musicology consisting of 128 microphones simultaneously recording at a 48-kHz sample rate. Here a radiation directivity method was developed suiting the great amount of microphones as well as the high sampling frequency. It uses not only the radiation strength but also the radiation directivity pattern of 128 points on the geometry as a dependent variable. This does not only allow for a precise reconstruction of the vibration of the instruments but also results in a detailed description of the radiation directivity for the overall geometry or for each radiating point individually. Furthermore the time-dependent reconstruction avoids any temporal integration and reconstructs the vibration of the geometry with the samplerate precision. With this method the different role and strength instrument parts have in the overall body radiation, scattering effects caused by geometrical inhomogeneities, and time-dependent initial transients reconstructed as radiation patterns were investigated. The material as well as the air parts of the instrument are considered simultaneously, i.e., with guitars or violins, the enclosed air radiating through the sound holes is investigated in relation to the surrounding plates.
Impact of suspended acoustical ceilings on the fire performance of open spaces.
Authors: Fritz Tom , Roy Kenneth
Published: October 2013

An architectural design trend referred to as the “exposed structure” look is becoming increasingly popular due to a number of emerging design factors. In some cases, there is a desire to expose the overhead mechanical systems and roof deck, thus providing a feeling of spaciousness and economy. Or, in other cases, the desire for openness is driven by the installation of underfloor air distribution, in which case a traditional overhead ceiling is not needed to cover plenum mechanicals. The architects and building owners must, however, be reminded that the occupant safety, satisfaction, and performance will often be negatively impacted by these architectural design decisions. In particular, the response time of fire safety devices may be adversely affected, as shown by simulation tests.
Gypsum board fire resistant assembly codes, standards, and certification.
Authors: Curkeet Rick , Nicholas John
Published: October 2013

Fire resistant (FR) assemblies are key components of building a life safety design. These assemblies are typically required to divide buildings into smaller compartments so that, should a fire start, it will remain confined for a sufficient period to allow evacuation and arrival of fire fighting personnel. Properly installed and maintained FR construction has a long history of performance in both saving lives and limiting fire related property damage. This presentation provides an overview of the process used to develop FR assembly ratings and listings where a gypsum wallboard is a key assembly component. The discussion includes the test methods and standards required by model building codes, the process used by designers and manufacturers to obtain design certifications, and how these designs are intended to be applied in the field. There are often occasions where a basic FR assembly may need to be altered to improve performance not directly related to fire resistance. This frequently includes addition or changes in materials or other aspects of a design to improve acoustical performance. However, all changes to FR assembly designs have the potential to change the fire resistance of the assembly. The process required to obtain acceptance of design modifications is discussed.
Elastic constant measurements at elevated temperatures.
Authors: Adebisi Rasheed , Gladden Josh
Published: October 2013

Resonant ultrasound spectroscopy (RUS) is a technique in obtaining the full elastic tensor of single crystal materials by measuring the mechanical resonances of a polished sample. Elastic constants of materials are a sensitive probe into the atomic environment; therefore, they are useful tools for studying phase transitions at high temperatures. A high-temperature system in which test samples are in direct contact with two transducers was designed to conduct RUS measurements up to 650 °C. Extremely high-temperature (∼650 °C) measurements are made possible by separating the sample, placed in a tube furnace, and the transducers with buffer rods made of low-acoustic attenuation materials with good thermal stability such as ceramic alumina or fused quartz. Results from the high-temperature measurements on a standard thermoelectric material, silicon-germanium, demonstrated that the system has the ability of acquiring resonance signals at temperatures up to 1000 °C. Experimental issues such as additional resonance peaks introduced by the buffer rods and sample loading will be addressed. The apparatus has been used to study phase transitions in transition metal oxides and novel Zintl phase thermoelectric materials. These results demonstrate the great potential of RUS methods in high-temperature physics.
Dispersion of plate acoustic waves in periodically poled lithium niobate.
Authors: Nadtochiy Andriy , Ostrovskii Igor
Published: October 2013

The phase and group velocity dispersion of the plate acoustic waves (PAWs) in ZX-cut periodically poled lithium niobate (PPLN) wafer is calculated theoretically and verified experimentally. The dispersion curves of eight lowest PAW modes are calculated with the help of the finite element method. The PAWs in PPLN have some peculiarities in comparison with the case of a single crystal waveguide. First, some PAW modes may reflect out of the multidomain structure, and so a band gap may occur in the PAW spectrum. For example, a zero antisymmetric mode A0 has 0.2-MHz-wide band gap at frequency where its wavelength is equal to the period of a domain pattern. Second effect includes a variation of a cutoff frequency of PAW. The experimental dispersion curves are in agreement with calculations. The phononic band gap of A0 mode and the cutoff frequency shift of first antisymmetric mode A1 are confirmed by our experiments. The group velocity is calculated from the experimental phase-velocity dispersion curves. The calculated and measured group velocities are consistent. It is shown that the group velocity of A0 mode approaches zero within the band gap.
Create an audio system to sonic boom an entire house?
Authors: Sparrow Victor , Garrett Steven
Published: October 2013

To establish thresholds of public acceptability, the Federal Aviation Administration (FAA) would like to determine if it is possible to design and build a sonic boom simulation device that can accurately reproduce a sonic boom over an entire building, or portion of a building, such as a residential home. Having such a sonic boom reproduction device would make it possible to perform subjective tests on people in their own homes when exposed to simulated sonic boom noise corresponding to aircraft that have not yet been built. This presentation describes an ongoing study directed toward the design of a simulation device that can accurately reproduce sonic booms over the entire exterior surface of a building. The authors will present some plausible strategies that are in the development stages. However, an additional motivation for this presentation is to make ASA members aware of this research and to solicit feedback from attendees prior to a January 2009 down-selection activity for the design of a system. The strict requirements for sonic boom playback fidelity make this project a Grand Challenge in Audio Reproduction. [Work supported by the FAA through the PARTNER Center of Excellence, www.partner.aero .]
Pressure and displacement fields inside an absorbing fluid sphere ensonified by a plane harmonic wave.
Authors: Foote Kenneth G. , Francis David T. I.
Published: October 2013

Analytic expressions have been developed for the pressure and displacement fields and dilatation in a lossy fluid sphere due to ensonification by a plane harmonic wave in a lossy immersion medium. These quantities have been computed for a 50-mm-diameter fluid sphere in water with a density of 1000 kg/m3 and a sound speed of 1500 m/s for each of two frequencies, 10 and 100 kHz, hence with wavenumber-radius products of order 1 and 10, respectively. The density and sound speed values in the fluid sphere have been varied to achieve contrast factors in the range of 0.5–2 relative to the respective medium property. Absorption in the fluid sphere has been varied over the range of 0–10 dB/m. Results are presented for each field quantity along the axis of the sphere, as defined by the direction of propagation of the incident wave, transverse to this axis from the center, and along the surface from the forward to reverse directions. [Work partly supported by NOPP through ONR Award No. N000140710992.]
The invariants of the time-reversal operator for asymmetric response matrices.
Authors: Simko Peter , Saniie Jafar
Published: October 2013

The decomposition of the time-reversal operator is a signal analysis method applicable to ultrasonic methods of target detection and characterization. In this paper, the eigenmodes of the time-reversal operator are studied for a single rigid cylinder with elliptical cross-section leading to an asymmetric response matrix formed by the interelement response of an active transducer array. The elliptical cylinder is of considerable interest in scattering problems since it encompasses within the limit both the circular cross-section case (very low eccentricity) and the strip (eccentricity approaching infinity). Variable cylinder properties will include parameters such as cross-sectional area, eccentricity, and angle of inclination of the semimajor axis with respect to the axis of a probing transducer array. Exact solutions for determination of the far-field response matrix using the familiar modal expansion with scattering coefficients computed via Mathieu functions will be discussed. The basis functions spanning the range of the time-reversal operator under conditions for which reciprocity no longer holds will also be discussed. Theoretical analysis will indicate that for scatterers near the Rayleigh limit, it is possible to characterize the aspect ratio of the target using a subarray method.
Physical principles behind quantal relations.
Authors: Hanson Helen M. , Stevens Kenneth N.
Published: October 2013

A distinctive contrast can be defined by a quantal relation between an articulatory parameter and an acoustic parameter. It is postulated that there are two sources of quantal relations. Aeromechanical interactions arise because the nature of the interaction of airflow with the compliant mechanical structures of the vocal tract can change abruptly as an articulatory parameter changes continuously. As a result, the nature of the generated acoustic source changes abruptly. Acoustic resonator coupling results from the fact that the vocal tract, together with adjacent structures, can create several cavities that can be coupled and uncoupled, resulting in a transfer function that can show an abrupt discontinuity as a consequence of the rapid movement of a zero. These two principles lead to a natural division of the distinctive features into two groups, articulator free and articulator bound. Because the features in the two groups are defined by different physical principles, relations among the features are quite different: the articulator-free features, being based on aerodynamic conditions in the vocal tract, are constrained hierarchically, while articulator-bound features have fewer constraints. The natural constraints among the features are such that the featural representation of a segment is rather sparse.
Language-independent phonetic definitions of distinctive features.
Authors: Clements G. N. , Ridouane Rachid
Published: October 2013

In spite of the fundamental role that distinctive features play in phonology and phonetics, current research continues to raise basic questions concerning how features can be defined in terms of measurable language-independent physical properties in the articulatory and acoustic/auditory domains. It has been proposed that for a feature to be recovered from a speech event, not only must its articulatory condition be met but the acoustic definition must be satisfied, in the absence of which further enhancing attributes must be present [K. N. Stevens, “Acoustic and perceptual evidence for universal phonological features,” Procedings of the 15th International Conference of Phonetic Sciences, Barcelona, 2003 (unpublished), pp. 33–38]. This paper addresses this proposal through the study of the phonetic feature (spread glottis), drawing upon acoustic, fiberscopic, and photoelectroglottographic data from Berber and Kabiyé. A definition for this feature is proposed which associates a specific articulatory state with an equally specific acoustic definition, holding for the full set of sounds and contexts in which this feature can be implemented.
Aggressive adaptive beamforming for ambient noise inversion with a limited-aperture sonar on an autonomous platform.
Authors: Arvelo Juan
Published: October 2013

Bottom loss inference from ambient noise inversion has been shown to yield accurate and robust predictions of undersea sound propagation and sonar detection performance using vertical line arrays and a conventional beamformer [J. I. Arvelo, J. Acoust. Soc. Am. 123, 679 (2008)]. However, any array with a vertical aperture should be good candidates for ambient noise inversion. The main problem with vertical line arrays is that they are not well suited to rapidly survey a large area. Platform translation with a vertical array is expected to cause extreme array shape distortions that could seriously limit the accuracy of the results. To mitigate array shape distortion, a smaller array with vertical aperture could be mounted on the survey platform, which would allow it to survey the area at greater speeds. The platforms’ diameter certainly limits the vertical aperture of the array. A limited vertical aperture limits the frequency range, resolution, and accuracy of the estimated bottom loss. Since the array is rigidly fixed to the platform's body, an aggressive adaptive beamformer may be adopted to increase the resolution and accuracy of the inverted bottom loss to very low frequencies. The performance is demonstrated via comparisons against conventional beamformers with numerical simulations and measurements.
Arrival time estimation from sound signals in the ocean: A particle filtering approach.
Authors: Jain Rashi , Michalopoulou Zoi-Heleni
Published: October 2013

The focus of this work is on accurate arrival time estimation from measured time-series at an array of vertically separated hydrophones in the ocean. We develop a particle filtering approach that treats arrival times as “targets”, dynamically modeling their “location” at arrays of spatially separated receivers. Using Monte Carlo simulations, we perform an evaluation of our method and compare it to conventional maximum likelihood estimation, whereas we also compare our errors to Cramer–Rao bounds. The comparison demonstrates an advantage in using the proposed approach, which can be employed for minimization of uncertainty in arrival time estimation. Improved arrival time estimates can then be used for accurate geoacoustic inversion and source localization. [Work supported by ONR.]