bluuebunny/crossref_metadata_2025 huggingface dataset:
Basic processes underlying speaking and singing: Preliminary acoustic and aerodynamic comparisons
Authors: Shah Amee P.
Published: October 2013

Intuitively, we think speech and singing are different. Perceptually, we hear the difference. Aesthetically, we appreciate the difference. Psychologically, we benefit from the positive effect of singing. The important question is whether this perceived difference is purely perceptual or is it grounded in physiological reality? It is important to identify the difference between speaking and singing if indeed there is one as it can shed light on our theoretical understanding of normal auditory perception and vocal production processes. Addressing this question has practical applications as well, as the findings could yield valuable information for working with clients in the fields of speech pathology and vocal music training. In addressing this question, the present investigation targeted broad areas to identify the differences between speech and singing. Specifically, respiration (the mechanics of breathing), articulation (the movements of the oral musculature), phonation (vocal-fold movement and air pressures), and acoustic attributes (temporal and spectral measures) were compared across speaking and singing. Surprisingly, and somewhat counterintuitively, results showed that speaking and singing are not as different as they are perceived to be. Results of preliminary acoustic and aerodynamic comparisons will be discussed as they help better understand the processes of singing and speaking.
The effect of stress on consonant vowel (CV) coarticulation: Decoupling of the CV bond
Authors: Agwuele Augustine , Sussman Harvey , Lindblom Bjorn
Published: October 2013

Two common sources of variation in the speech signal arise from (1) naturally imposed speaking conditions (e.g., stress, tempo), overlaid onto (2) inherent contextual influences. Coarticulatory analyses are affected by both sources of variation, but rarely are they dissociated. The focus of this study was to derive quantitative methods to assess the effect of emphatic vowel stress on preceding stop consonant onsets, apart from, and independent of, anticipatory effects of changing vowel contexts. Three speakers produced V1CV2 tokens, with emphatic stress either on V1 or V2; C=/bdg/. There were six V1 and 10 V2 vowel contexts. Novel methods were applied to both standard locus equation scatterplots and multiple regression analyses to isolate F2 midvowel (Hz) and F2 onset (Hz) adjustments as a function of emphatic stress. The analyses show how stress differentially affects the V-midpoints and C-onsets for labial /b/ relative to lingual stops /dg/.
Spectral properties of Japanese whispered vowels referred to pitch
Authors: Konno Hideaki , Kanemitsu Hideo , Toyama Jun , Shimbo Masaru
Published: October 2013

Whispered speech can communicate the same linguistic information as ordinary speech in spite of the great difference of their respective acoustic characteristics. In this respect, whispering is an interesting object for studying speech perception and recognition. In this study, we investigate the spectral properties of five whispered Japanese vowels uttered in isolation and having different pitch. Pitch of ordinary whispered vowels was measured in terms of the manner in which the talkers were listening to pure tones while uttering and adjusting its frequency so that the pitch matched the utterance. For other samples, talkers changed the pitch of utterances to match the given pure tones. Acoustic analyses were carried out on formant frequencies, a spectral tilt, and a peak frequency of wide-ranging spectral shape using second-order LPC method called a global peak. Preliminary results show a tendency of upward shift of F1, F2, and global peaks, and flattened spectral tilts on overall vowels with increasing pitch. The intended pitch by a talker is not correspondent to a specific formant frequency. Results of pitch comparison tests among samples and pitch matching test with pure tones will also be discussed. [Work supported by MEXT Japan.]
Detecting nonlinearity in voice production systems
Authors: Zhang Yu , Tao Chao , Jiang Jack J.
Published: October 2013

Many biomedical systems exhibit some form of nonlinear behavior, such as saturation in response to certain inputs. Linear description may not be sufficient to describe the complex nonlinear phenomena, including bifurcation and chaos. The determination of nonlinearity from time series has become an important topic for the analysis and modeling of biomedical systems. In this study, we will apply nonlinear dynamic modeling based on Volterra kernel function to describe the nonlinearity of voice signals. Three nonlinear parameters including nonlinearity-to-linearity amplitude ratio (NLAR), nonlinearity-to-linearity parameter ratio (NLPR), and nonlinear order are employed. Sufficiently lower NLAR and NLPR, and a nonlinear order approaching 1 can be found in periodic voice signals, demonstrating the linear mechanism of periodic voice production. However, aperiodic voices show sufficiently high NLAR and NLAR, and a nonlinear order above 2, indicating the dominant role of nonlinearity in disordered voice production. Furthermore, the effects of the signal length and noises on these three parameters are investigated. These three nonlinear parameters show the robustness of short signal length and noise perturbations, demonstrating their potential applications in measuring the nonlinearity of disordered voice production systems. [Work supported by NIH.]
Database construction and analysis of user speech with real environment spoken guidance systems
Authors: Kawanami Hiromichi , Kida Manabu , Cincarek Tobias , Shikano Kiyohiro
Published: October 2013

A spoken guidance information system ‘‘Takemaru-kun’’ has developed and been operated in a public city center in Ikoma city, Nara, Japan since November 2002. The system employs the example-based response selection strategy and answers to users’ questions about the hall facility, the city, sightseeing, etc. with CG agent animation. Following the success of the system, two new spoken systems ‘‘Kita-chan’’ and ‘‘Kita-chan robot’’ were developed and were set on a railway station since March 2006. ‘‘Kita-chan robot’’ is being operated with a robotlike agent. All user speech of the systems is recorded and two year’s data of ‘‘Takemaru-kun’’ and one month’s data of ‘‘Kita-chan’’ systems are manually transcribed and labeled by age and gender. Proper answers are also given to each utterance. In this paper, details of the three user speech databases are described and analytical results concerning numbers of inputs and response accuracy and age group and gender are reported.
Khmu voice register: Acoustic analysis and perceptual experiments
Authors: Abramson Arthur S. , Nye Patrick W. , L-Thongkum Theraphan
Published: October 2013

Khmu has phonological voice registers, i.e., bundles of phonetic properties pertinent to the syllable. Auditory observations claim clear voice and high pitch for register 1 and breathy voice and low pitch for register 2. Although Suai registers were in flux [Abramson et al., Phonetica 61, 147–171 (2004)], it was understood that Khmu Rawk had a stable distinction. Words were recorded by 25 native speakers. Acoustic analysis yielded F0 and overall amplitude contours, frequencies of F1 and F2 in quasi-steady states of the vowels, relative intensities of higher harmonics to that of the first harmonic, and vowel durations. When circumstances caused early attention to perception testing, the words of only eight speakers had been analyzed. Since the only significant factor that had emerged by then was F0 contour, the synthetic stimuli were made with a series of seven contours. The labeling by 32 native speakers yielded two categories, demonstrating the sufficiency of F0 as an acoustic cue. The completed acoustic analysis showed a significant effect of the harmonic ratios for the women, suggesting a conservative bias. The language is shifting toward tonality. Further perception testing must be done for phonation-type effects. [Work supported by NIH and the Thailand Research Fund.]
Modeling scattering from simple three-dimensional bathymetric features using wave-field superposition
Authors: Fawcett John A.
Published: October 2013

In the method of wave-field superposition a set of point sources inside or outside of a scattering region can be used to represent the exterior or interior acoustic fields. A method is presented that represents a simple bathymetric feature as a closed scattering region in an otherwise flat water-seabed environment. In particular, the feature is taken to be azimuthally symmetric about the vertical axis, thus allowing the three-dimensional scattering problem to be solved in terms of a set of two-dimensional problems. These problems are solved using the method of wave-field superposition. Numerical examples are presented. As well, a benchmark solution in the case that the surrounding medium has only a density jump at the seabed is derived and compared with the more general numerical approach.
Validating physics-based clutter from seafloor roughness and biologic scattering
Authors: Arvelo Juan , Monjo Charles , Newhall Bruce , Frankel Adam , Love Richard , Ellison William T.
Published: October 2013

Two physics-based clutter models were developed for comparison and to study the merits and limitations of both approaches. The stochastic approach [Newhall and Arvelo, J. Acoust. Soc. Am. 118, 2041 (2005)] makes use of perturbation theory, to relate the mean seafloor scattering strength to the mean surface wavenumber spectrum, and the extrapolation of this spectrum to the Bragg wavenumber to generate the clutter distribution from the seafloor roughness. The semi-deterministic approach [Monjo and Arvelo, J. Acoust. Soc. Am. 118, 2041 (2005)] is based on 2-D power-law fractal realizations of the ocean floor, coherent modal addition, and the microscale bathymetric slopes. Biologic scattering was later included where spatial distribution and nonstationarity of schools of fish and individual marine mammals are realistically represented [Frankel et al. J. Acoust. Soc. Am. 119, 3437 (2006)] through individual-based modeling of their movements, school size, and target strengths. Clutter distributions from both approaches are compared against each other, for selected test cases, and against clutter measurements. [This effort was funded by the Maritime Sensing Program of the Office of Naval Research (ONR Code MS 321).]
Reducing source localization errors: A visualization method to help guide the design, calibration, and use of widely separated acoustic sensor arrays
Authors: Berchok Catherine L. , D’Spain Gerald L. , Hildebrand John A.
Published: October 2013

The use of acoustic arrays to obtain source positions of vocalizing animals has become quite common in field studies of wild animal populations, but the results presented rarely include error bounds, leading to a false sense of confidence in the animal locations. As research from the acoustics community has shown, these source localization errors vary with respect to bearing and distance from the array and are generated by measurement uncertainties associated with the propagation environment, field equipment, and data processing/analysis methods. However, these errors can be reduced by making informed decisions about the design, calibration, and deployment of the arrays and by including measurements of amplitude ratios and vector sensor bearings in addition to time-of-arrival differences. A numerical method is presented here that allows for visualization and quantification of the impact of measurement uncertainties on source localization error bounds for widely spaced acoustic sensor array. This method will be used to show how quick comparisons of source localization error bound maps can help determine appropriate array designs for a particular field application. Among the parameters compared are array geometry, beamforming techniques, and measurement of various combinations of properties of the received acoustic field. [Work supported by a Hunt Postdoctoral Fellowship.]
Current structure measurements by the coastal acoustic tomography
Authors: Kaneko Arata , Yamaguchi Keisuke , Lin Ju , Gohda Noriaki , Zheng Hong , Takasugi Yoshio
Published: October 2013

The coastal acoustic tomography (CAT), coastal-sea application of deep-sea acoustic tomography (Munk and Wunsch, 1978), is proposed as an advanced technology to map current structures in the coastal sea. A sequence of successful experiments was recently carried out in the coastal seas with various oceanographic conditions around Japan (Yamaguchi et al., 2005; Kaneko et al., 2005; Lin et al., 2005). In the Tokyo Bay experiment of November 2002, the 2-D tidal currents inducing a clockwise residual circulation were mapped by eight CAT systems, located at both the eastern and western coasts of the bay. The vortex-embedded tidal currents with a maximum velocity of 5 ms−1 were targets in the Kanmon Strait experiment of March 2003. In the Hiroshima Bay experiment of September 2003, the stratified sea was shifted to the homogenized sea after the passage of a typhoon. The transition of tidal current structures before and after the typhoon was well measured by seven CAT systems, located at the northern coast and on the southern oyster rafts. The procedure of 2-D current mapping for the coastal seas with depths shallower than about 30 m is well established through a sequence of CAT experiments mentioned above.
Shallow-water tomography: Is it a good idea?
Authors: Lynch James F. , Duda Timothy F.
Published: October 2013

There seems to be a feeling among ocean acousticians that anything that can be measured acoustically should be measured acoustically. However, there are two drawbacks to that point of view, comforting as it might be to us acousticians. First, many things that one would think are measurable with acoustics are actually not measurable, or are only barely so. And second, acoustics may turn out to be a poor or cost-ineffective measurement compared to other techniques. In this paper, we will look at whether acoustic tomography is viable, can produce high-quality measurements, and is cost effective in shallow water. We will use feature resolution, cost, reliability, intrusiveness, averaging properties, and other measures to obtain a weighted description of how effective tomography is for typical shallow-water (coastal) applications and then compare this to the same measure for other (conventional) oceanographic measurement systems. [Work supported by ONR.]
A modular system yielding jazz-style arrangement for a given melody and sequence of chord names
Authors: Emura Norio , Yanagida Masuzo , Miura Masanobu
Published: October 2013

There are many music systems available on the market, such as ones for automatic arrangement of music pieces given as note sequences for solo piano into a piano score in a specific style. Those systems, however, are usually designed to generate music by concatenating existing arrangement patterns, so we cannot expect those systems to meet user requirements. This paper proposes a system that arranges a given set of melody expressed as a note sequence and a chord name sequence into a piano score in modern jazz style based on so-called ‘‘jazz theory.’’ The system is implemented in the classical theory of harmony and arrangement techniques described in jazz theory in a modular system. Proposed is a system that gives arrangement by integrating several modules according to structure of input music and user requirements. Performance of the proposed system is evaluated by comparing results given by the proposed system with those given by popular arrangement systems available on the market. Experimental results show that arrangement by the proposed system is significantly superior to arrangement by other systems available on the market. [Work supported by Academic Frontier Project, Doshisha Univ., Knowledge Cluster Project, MEXT, Grant-in Aid for Scientific Research (No. 16700154), MEXT, HRC, Ryukoku Univ.]
Beam sweeping in sediment layer using phase-conjugated pseudo sound sources
Authors: Tsurugaya Yoshiaki , Kikuchi Toshiaki , Iwase Ryoichi , Mizutani Koich
Published: October 2013

When an object that is buried in a sediment layer is detected from the diagonal, detection is hampered by reflection from the bottom surface. Stated in different terms, the sound-wave energy that reaches the object is small because of the reflection and refraction that occurs at the bottom surface when a sound wave is applied to the object in the sediment for diagonal detection. To alleviate that problem, a pseudo sound source can be set up in sediment layer. The sound wave radiated from the pseudo sound source is then received by a time-reversal array. The sound wave can be injected into the sediment layer by reversing the received signal with time and radiating it again from the time-reversal array. The beam can hit the target through movement of this pseudo sound source along the bottom surface. The sound wave that hits the target is reflected and returns in water. The sound wave is subsequently reflected many times at the surface and bottom and is diffused over time. The passive-phase conjugate processing is then given to the received diffusing signal to reduce this diffusion. The pulse is compressed by this processing, thereby obtaining the target position. a)Currently at NDA; b)Currently at JAMSTEC; c)Currently at Univ. of Tsukuba.
Robust wideband time-reversal using time-domain principal component analysis
Authors: Higley W. J. , Roux Philippe , Hodgkiss W. S. , Kuperman W. A. , Song Heechun , Akal Tungay , Stevenson J. Mark
Published: October 2013

Time reversal (TR), a two-step process, involves time reversing the measured transfer functions from a source and then retransmitting this signal to produce a focus back at the source position. When attempting TR in a fluctuating ocean environment, it is desirable to alter the transmitted signal such that it produces a more robust focus. This has typically been done with work based on frequency domain analysis. In contrast, this work, using oceanic data measured during FAF05, is broadband and the development is totally in the time domain. Different definitions of robustness give different optimal answers to the question of how to design the most robust transformation of the time-reversed data of the first step in the TR process. Two definitions of robustness are studied, one related to outage probability and another related to average power. For each definition, a different approach to a practical approximation is taken. In the case of outage probability, we iteratively solve a minimax optimization problem. In the case of average power, principal component analysis is performed on time-domain data.
Identification and classification of resonant targets with iterative, single-channel time reversal in a noisy environment
Authors: Waters Zachary J. , Holt R. Glynn , Roy Ronald A. , Dzikowicz Benjamin R.
Published: October 2013

The identification and classification of mines resting on and buried beneath the sea floor is an important and challenging problem. Previous numerical results indicate that iterative time reversal using a single-element transducer increases the signal-to-noise ratio of the backscattered return while simultaneously converging to a narrow-band signal characteristic of the scattering target [D. M. Pierson, ‘‘Buried object detection using time-reversed acoustics,’’ Ph.D. dissertation, North Carolina State University 2003]. This technique offers an inexpensive and simple means for maximizing signal level in a noisy or cluttered environment. We investigate this phenomena through experiments performed in a water tank using a 6.35-mm-diam hollow steel sphere and broadband Q∼1.5) piston transducers operating in the 100-kHz to 2-MHz frequency range. Time-reversal convergence of the interrogation pulse was readily achieved using a variety of broadband (0.1–2 MHz) pulses to initiate the process. Results indicate that the spectrum of the echo rapidly converges to the dominant resonant mode of the target, with a significant enhancement in signal level even in the presence of broadband noise and coherent clutter returns. [Work supported by Office of Naval Research Award No. N000140610044.]
Numerical analysis of sound propagation in rooms using the finite difference time domain method
Authors: Sakamoto Shinichi , Ushiyama Ayumi , Nagatomo Hiroshi
Published: October 2013

Impulse response is an important quantity for room acoustics. To predict the impulse response, several types of calculation methods based on wave theory, such as the boundary element method (BEM), finite element method (FEM) and finite difference method (FDM), are being investigated. Among them, the authors are exploring application of the finite difference time domain (FDTD) method to calculate room sound fields. Using the method, by which the acoustical quantities at discrete grid points of a closed field are successively solved step-by-step according to vector operations, the impulse responses can be obtained directly in a time domain using little computer memory storage. Furthermore, changes of spatial distributions of room sound fields in time can be obtained easily by storing the sound pressure at grid points and displaying them by animation. In this presentation, several examples of the FDTD analyses of room impulse responses are reported and computer animation of their room sound fields is introduced. In addition, examination of the applicability of prediction of the impulse responses by comparison with in situ measurement of a small hall is discussed.
Absorption and aperture size effects on subjective response to complex computer modeled coupled volume systems
Authors: Bradley David T. , Wang Lily M.
Published: October 2013

A typical coupled volume concert hall consists of a large, absorbent main volume linked to a smaller, reverberant auxiliary space through a series of acoustically transparent openings. This type of space can exhibit a nonexponential sound decay, a phenomenon that is referred to as the double slope effect (DSE). An imagined, realistic coupled volume concert hall has been computer modeled, and room impulse responses of the space have been obtained. Several configurations of the hall were conceived in which the absorption and aperture size were modified. Paired-comparison tests were conducted to determine listener preference for the sound fields developed from auralizations of the configurations. The results from this subjective testing were statistically analyzed using multidimensional scaling methods. The analysis showed that listener preference increased with decreasing DSE, with highest preference levels for low and medium DSE. These results will be presented and contrasted with objective parameters calculated from the room impulse responses of the computer-modeled configurations.
Effects of peg’s positions of low-registered strings on acoustic gain by a stage riser: Theoretical model analysis
Authors: Nakanishi Shinsuke
Published: October 2013

This paper theoretically analyzes acoustic gain by a stage riser, which has been observed when playing the low strings, e.g., a violoncello and a double bass, on the riser in concert auditoria [Beranek et al., J. Acoust. Soc. Am. 36, 1247–1262 (1964)]. The previous paper reported that ‘‘the tone quality increased in richness with the risers, particularly when the pegs of the instruments were placed about 4 in. from the edge’’ as musician’s comments. The author discusses effects of the peg’s positions of the low strings on the acoustic gain, through numerical examples of theoretical model analysis. The solution of a sound field is obtained when playing the low string on the riser placed on the rigid floor, which receives a spherical incident wave and mechanical excitation force from the low string. Numerical examples show that peg’s positions of the low string affect peaks and dips of the acoustic gain, which are caused by eigenvibrations of a top plate of the riser. And, the acoustic gain becomes a positive value at more frequencies as the standing position of the low string shifts towards the riser’s edge.
Bottom-mounted hydrophones used to investigate sperm whale click and swim characteristics
Authors: Nosal Eva-Marie , Frazer L. Neil
Published: October 2013

A method that relies solely on the time difference between direct and reflected arrivals (DRTD) on individual hydrophones was previously used to localize a single sperm whale [E.-M. Nosal and L. N. Frazer, Appl. Acoust., Special Ed.: Detection and Localization of Marine Mammals using Passive Acoustics (in press)]. Regular clicks in recordings from five bottom-mounted hydrophones in the AUTEC range were used in the localization. In this study, the DRTD method is extended by incorporating time differences (between hydrophones) of direct arrivals to refine the track of the whale and to determine the time of generation of individual clicks. Clicks, which have a multi-pulse structure, are analyzed in detail to determine changes in interpulse intervals (IPI) with time. The resulting time, location, and IPI information are used to investigate swim patterns and directionality characteristics of regular sperm whale clicks. [Work supported by ONR. Data provided by NUWC for the 2nd International Workshop on Detection and Localization of Marine Mammals using Passive Acoustics.]
The acoustic recording of bottlenose dolphin (Tursiops truncatus) phonations: Problems and contributions
Authors: Bazúa-Durán Carmen , Herrera-Hernández Axel
Published: October 2013

Bottlenose dolphin sounds have been studied for decades; however, more needs to be investigated. This work demonstrates that results obtained in wild dolphin studies greatly depend on the recording system used. Dolphin phonations were simultaneously recorded with two systems, a narrow-band (<24 kHz) and a broadband (<180 kHz), and were analyzed using spectral characteristics (narrow-band: 512 points, Hamming window, 50% overlap; broadband: 2048 points, Hamming window, 50% overlap) to determine the acoustic repertoire as echolocation click trains (EC), whistles (W), and burst pulses (BP). As expected, the number of BP and EC recorded was considerably larger with the broadband system than with the narrowband; whereas the number of W recorded was greater with the narrowband system than with the broadband (it was expected to obtain the same number of W with both systems). As W are less intense than BP or EC, when gain is adjusted for recording BP or EC, the recording system is not able to record the less intense W. Therefore, it is not possible to capture the same number of dolphin phonations with the same recording system. One should use at least two different recording systems to adequately describe dolphin phonations. [Work supported by CONACyT-Campeche and PAPIIT-UNAM.]
Acoustic monitoring of resident, offshore, and transient killer whales off the Washington coast
Authors: Oleson Erin M. , Wiggins Sean M. , Hildebrand John A.
Published: October 2013

Three acoustically distinct populations of killer whales representing each of the known ecotypes (resident, offshore, transient) were recorded in the Summer–Fall of 2004 off the southern Olympic Coast of Washington. Two high-frequency acoustic recording packages (HARPs) continuously recording at 80-kHz sample rate were deployed to assess the seasonal occurrence of vocal odontocetes in this region. From mid-July to early-October the population-specific discrete calls of killer whales were heard on 8 days and were classified to population by Volker Deecke (UBC) and John Ford (DFO-Canada) using an acoustic ID catalogue. West Coast Transient killer whales producing calls of the California dialect were heard on three occasions from August through October. Offshore killer whales were heard twice in August–September, and Northern Resident killer whales were heard once in August. Although Northern Resident killer whales have been extensively studied within Puget Sound and coastal British Columbia, they have been visually sighted only once off the northern Olympic Peninsula, making their detection at this offshore southerly location unique. Endangered Southern Resident killer whales were not heard at this site from July–October. Analysis of year-round data from a site further offshore is underway. [Funded by Chief of Naval Operations- N45.]
Ocean acoustic thermometry and the seasonal cycle of temperature in the North Pacific Ocean
Authors: Dushaw Brian D. , Andrew R. , Howe B. , Mercer J. , Cornuelle B. , Dzieciuch M. , Munk W. , Worcester P. , Birdsall T. , Metzger K. , Menemenlis D. , Spindel R.
Published: October 2013

With several years of long-range (several Mm) acoustic propagation data obtained during the Acoustic Thermometry of Ocean Climate (ATOC) and North Pacific Acoustic Laboratory (NPAL) projects, the seasonal cycle of ocean temperature in the North Pacific can be examined. Acoustic transmissions have been made from a source located off the northern Californian coast and from a source located north of Kauai, HI to several receivers of opportunity located in the North Pacific Basin. The acoustic data are a high signal-to-noise measure of large-scale temperature with excellent temporal resolution. Although only a few realizations of the seasonal cycle are available, it is clear that inter- and intraannual variabilities are large contributions to the time series, with signal amplitudes comparable to the seasonal cycle. Such variabilities are likely advective in origin. The time scales for some of the changes in temperature are short, sometimes of order weeks. Not all available acoustic paths are suitable for assessing the seasonal cycle, however. Near Hawaii, the acoustic sampling does not extend to the near-surface waters, so seasonal variations there are not measured. The acoustic results will be compared to measures of the seasonal cycle by satellite altimetry, profiling floats, and the ECCO numerical ocean model.
The SPICEX (Spice Experiment) component of the 2004 North Pacific Acoustic Laboratory (NPAL) experiment: An overview
Authors: Worcester Peter F. , Dzieciuch Matthew A. , Van Uffelen Lora J. , Rudnick Daniel L. , Cornuelle Bruce D. , Munk Walter H.
Published: October 2013

The objectives of the SPICEX component of the 2004 North Pacific Acoustic Laboratory (NPAL) experiment were (i) to elucidate the relative roles of internal waves, ocean spice, and internal tides in causing acoustic fluctuations; (ii) to understand the acoustic scattering far into the geometric shadow zone beneath caustics previously seen on bottom-mounted SOSUS receivers (shadow-zone arrivals); and (iii) to explore the range dependence of the fluctuation statistics. Two vertical line array receivers deployed in close proximity in the central North Pacific Ocean, together spanning much of the water column, recorded transmissions from broadband 250-Hz sources moored at the sound channel axis (750 m) and at surface conjugate depth (3000 m) at ranges of 500 and 1000 km from June through November 2004. Extensive environmental measurements were made along the acoustic path. The acoustic data from SPICEX reveal the vertical structure of the deep shadow zone arrivals. Internal waves are able to account for much of the observed vertical scattering in the reception finale, but other mechanisms seem necessary to account for the early shadow zone arrivals. Receptions from the abyssal sources show scattering occurring predominantly along the acoustic time fronts, as previously suggested by simulations, rather than across them.
Seafloor hydrophone and vertical geophone observations during the North Pacific Acoustic Laboratory/Long-range Ocean Acoustic Propagation Experiment (NPAL/LOAPEX)
Authors: Stephen Ralph A. , Mercer James A. , Andrew Rex K. , Colosi John A.
Published: October 2013

Four OBSs (ocean bottom seismometers), consisting of one hydrophone and one vertical component geophone channel each, were deployed below the deep vertical line array (DVLA) on the North Pacific Acoustic Laboratory/Long-range Ocean Acoustic Propagation Experiment (NPAL/LOAPEX). The OBSs were deployed at 2 km offset north, south, east, and west from the nominal DVLA location. Data, sampled at 500 sps, were recorded continuously from the deployment in September 2004 for over 100 days. The OBSs were on the seafloor in about 5000 m of water and would be in the shadow zone for long-range, ducted propagation in the sound channel. The goals of the deployment were (1) to quantify the amount of energy that leaks out of the sound channel into the shadow zone; (2) to measure the relative sensitivity (signal-to-noise) of seafloor hydrophones and vertical component geophones to long-range signals; and (3) to study the physics of earthquake generated T-phases. Leakage was observed out to 3200 km on the vertical component geophone and out to 1000 km on the hydrophone. The ratio of the pressure to vertical velocity varies between arrivals on the same trace. [The OBS deployments were funded by contributions from ONR, NSF, and WHOI. Data analysis funded by ONR.]
Analysis of low-mode arrivals at 500 and 1000-km ranges in the North Pacific
Authors: Wage Kathleen E. , Worcester Peter F. , Dzieciuch Matthew A.
Published: October 2013

Experimental measurements of low-mode signals in the deep ocean are needed to verify statistical models and to design improved processing algorithms for these signals. Several long-range propagation experiments provided estimates of low mode statistics at ranges between 3 and 5 megameters [Wage et al., J. Acoust. Soc. Am. 117, 1565–1581 (2005)]. The 2004–2005 SPICE experiment included measurements at shorter ranges and a higher frequency than previous experiments. A 40-element vertical line array (VLA) received signals from two broadband sources at ranges of 500 and 1000 km. Both sources were moored at depths near the sound-channel axis; thus, they directly excited the lowest modes. The VLA was designed to spatially resolve 20 modes at the center frequency of 250 Hz. In addition to hydrophones the SPICE array included temperature and salinity sensors, which can be used to infer sound speed, and hence mode shapes, at the VLA. This talk describes an analysis of the low-mode arrivals in the SPICE data set. The presentation will include a discussion of mode filter design, focusing on how often the filter coefficients need to be updated to avoid problems with environmental mismatch. [Work supported by ONR.]
Acoustic computed tomography: Waves of approaches
Authors: Greenleaf James F.
Published: October 2013

Computed tomography (CT) using acoustic waves was invented at about the same time as MRI. The method of computing attenuation from projections was a direct analog of the x-ray CT approach. However, the method of computing speed from the time of flight of the acoustic ray was a larger logical jump. The field started with straight ray, earliest arrival time methods and has matured to what can be termed the full wave equation inversion method. The extension from two dimensions to three, although essential in the body, did not find a practical solution until very recently. The inverse problem represented by this field has found the attention of many investigators over the years. Practical medical implementations continue being investigated by several investigators more than 30 years after the first invention of the method. Acoustic tomography has been applied in nonmedical areas including oceanography, seismic, and solar sciences. Time awaits its success in medicine.
On the use of inverse scattering tomographic methods for quantitative ultrasound techniques
Authors: Lavarello Roberto J. , Oelze Michael L.
Published: October 2013

The application of the distorted Born iterative method (DBIM) is proposed to construct tomographic images of small scale structures. Specifically, DBIM is proposed as a tool to construct better ultrasonic models of cells in order to improve the accuracy of quantitative ultrasound (QUS) analysis. An alternative implementation of DBIM valid for measurement configurations where the receiver positions are fixed is discussed. In addition, a method for the selection of the regularization parameter is determined, based on the Rayleigh quotient iteration. QUS imaging has been used to differentiate malignant from benign tissue. Recently, cells have been hypothesized as an important source of scattering in tissue. Generating tomographic images of sound speed and density of cells would allow better models to be constructed. Because the contrast mechanism in cells is unknown, the effect of variable density is explored. Stage II–III Xenopus oocytes are proposed as an initial cell model for scattering, with typical sizes ranging between 300 and 600 μm. Based on measurements of the propagation delay through oocytes, it was determined that their diameters correspond to at most 24 resolution cells when using single-frequency DBIM. Hence, frequency hopping may be required to discriminate smaller features inside the oocytes.
Photoacoustic imaging with a planar measurement array: Improving the resolution using image sources
Authors: Cox Benjamin T. , Arridge Simon. R. , Beard Paul C.
Published: October 2013

Biomedical photoacoustic (PA) imaging is a soft-tissue imaging modality that combines the high spatial resolution of ultrasound (US) with the contrast and spectroscopic opportunities afforded by imaging optical absorption. Exact reconstruction algorithms for PA imaging have been described for spherical, cylindrical, and planar sensor arrays. Many applications to date have used a cylindrical measurement geometry because a single US transducer may be scanned straightforwardly in a circle around a sample. However, planar US arrays composed of piezo or optical elements with small element sizes and fast acquisition times are readily available, making them an attractive option for imaging applications. To capture sufficient data for an exact PA reconstruction with a planar geometry requires an infinitely wide array. In practice, of course, it will be finite, resulting in a loss of resolution and introducing artefacts into the image. To overcome this limitation, it is proposed that acoustic image sources are used to generate a periodically repeating sound field that can be reconstructed exactly from measurements made over a finite aperture. [This work was funded by the EPSRC, UK]
An acoustic technique to assess particle distribution following transcutaneous needle-free injection
Authors: Condliffe Jamie , Collin Jamie R. T. , Costigan George , Coussios Constantin-C.
Published: October 2013

Needle-free injection is a novel technique enabling pain-free transdermal drug and vaccine delivery. The present work aims at developing a noninvasive, ultrasonic technique to assess distribution of drug particles delivered in this manner beneath an optically opaque layer, such as the skin. Drug particles are modeled as a monodisperse distribution of 50-μm polystyrene spheres that are injected into an agar-based tissue-mimicking material, which they penetrate to a mean depth of 500 μm. A 15-MHz broadband focused immersion transducer, driven in pulse-echo mode, was used to scan the surface of the agar phantom. By assuming that the mean-squared voltage of the received waveform is proportional to the number of particles encountered by the incident pulse, a 3-D map of particle distribution was generated. The resulting acoustic microscopy data were validated by examining phantom slices of thickness similar to the acoustic pulse length under a conventional optical microscope. The acoustic technique was found to provide a good prediction of the mean particle penetration depth and an accurate map of transverse particle distribution in planes normal to the direction of injection. It thus shows great promise as a noninvasive means of assessing the efficacy of needle-free injection, both in vitro and in vivo.
Removing multiples and depth imaging and inverting primaries without knowing or determining the velocity model: A response to pressing seismic challenges
Authors: Weglein Arthur B.
Published: October 2013

The isolated task specific subseries of the inverse scattering series represents a direct response to many pressing seismic exploration challenges. Those challenges often involve removing multiply reflected events and locating and identifying targets when the subsurface properties and boundaries are rapidly varying and beyond all current methods to adequately predict and estimate. The goal of these fundamentally new concepts and algorithms is to make currently inaccessible targets accessible and accessible targets better defined. We will exemplify these new algorithms with synthetic and field data. Open issues and plans will be discussed.
Seismic imaging of subduction zone deformational structures using 3D seismic profiling
Authors: Bangs Nathan L.
Published: October 2013

In the past 15–20 years, considerable efforts have been made to image complex deformational structures beneath the seafloor at subduction zones using seismic imaging techniques. The goals have been to: 1) accurately image structures to determine the geometry of thrust faults controlling the deformation and tectonics of plate collision at subduction zones, and 2) to determine the rock physical properties from seismic reflections to infer fault zone mechanical properties and examine conditions leading to fault rupture and earthquake generation. Subduction zones generate the world’s largest and most destructive earthquakes and tsunamis and accurate seismic images of faults to depths of 6–7 km below seafloor offer an opportunity to examine conditions at these inaccessible depths. Three-dimensional seismic techniques have proven to be critical for sampling the reflected wavefield at the sea surface sufficiently to be able to migrate reflections to their proper subsurface positions and construct accurate images. I will present examples of these 3-D seismic reflection images, analyses of these data, and future directions. [Work supported by NSF.]
Application of CHIRP data to neotectonic, sediment dispersal and sea level studies
Authors: Johnstone Elizabeth , Driscoll Neal
Published: October 2013

CHIRP seismic data will be presented in order to demonstrate the importance of subbottom imaging in addressing fundamental problems in Earth sciences. Examples from actively deforming regions in California place important constraints on the rupture history along major fault systems as well as tectonic control on sediment preservation and exposure of hardgrounds on the seafloor. Tectonic deformation creates a rich tapestry of geologic substrate exposed on the seafloor, ranging from mobile sands to lithified hardgrounds. It is this heterogeneity of the seafloor that creates different biological ecosytems and consequent increased biodiversity. CHIRP data have also provided new insights into sediment dispersal and clinoform development in the Gulf of Papua. In the northern gulf, oblique clinoforms suggest the rate of sediment supply has outstripped the formation of accommodation, whereas in the south the sigmoidal package indicates that accommodation increased faster than sediment supply. The morphology and internal geometry of the clinoform itself are inherently three-dimensional. The underlying physiography also appears to play an important role in governing sediment dispersal and distribution.
Acoustical analysis of nonlinguistic sounds
Authors: Inverso Yell , Bickley Corine , Limb Charles
Published: October 2013

The perception of speech is an undisputed important goal for cochlear implantation; however, the reception of nonlinguistic sounds (NLS) is also important. Nonlinguistic sounds are important for one’s safety and they are considered to have importance to a person’s sense of connection to and welfare in one’s environment. NLS are different from speech, and the perception and acoustic characteristics of NLS have not been studied adequately to allow clinicians to fit CIs for optimal recognition of both speech and NLS. The specific categories of nonlinguistic sounds to be evaluated in this study are (1) human vocal/nonverbal, such as a baby crying or a person coughing; (2) mechanical/alerting, such as a telephone or an alarm clock buzzing; (3) nature/inanimate, such as weather sounds; (4) animal/insect, such as a dog barking; and (5) musical instruments such as the strum of a guitar. In this ongoing study, 50 listeners (half adults with normal hearing and half adult post-ling deafened CI users) are being evaluated with respect to their ability to identify the sources of a variety of common, everyday NLS. In this poster, an acoustic analysis of a representative set of the stimuli will be presented.
Contribution of continuous infrasound monitoring to scientific research
Authors: Le Pichon Alexis , Antier Karl , Ceranna Lars , Drob Doug , Lardy Michel
Published: October 2013

Continuous automatic processing of the data is being performed at the French NDC from a number of IMS-type infrasound stations in order to detect and characterize coherent infrasonic waves recorded on the arrays. A large number of detections are associated with natural phenomena. Infrasonic waves generated by strong earthquakes occurring within region of high mountains are of great interest. Such events allow the evaluation of the relative contributions of the different source mechanisms involved in large earthquakes, and offer an opportunity to improve our understanding of the amplification of ground displacement caused by the topography. Microbaroms as well as mountain waves are quasipermanent sources of infrasonic waves detected on a global scale. Their monitoring reveals clear periodic trends in the detected bearings and signal amplitude, providing further confirmation that long-range propagation strongly depends on the atmospheric conditions. Signals from volcanic activities also offer a unique opportunity for atmospheric studies. At large propagation ranges from the volcanoes, infrasound measurements can be used as input of inversion procedures to evaluate more precisely the vertical structure of the wind in a range of altitude unaccessible to ground-based or satellite measurements.
Infrasound from tornadoes and other severe storms
Authors: Noble John M. , Bedard Alfred J.
Published: October 2013

Infrasound arrays have been used for a long time to detect and monitor man-made and natural acoustic sources below 20 Hz. Much of the earlier work on infrasound from severe weather was below 0.1 Hz and was related to severe weather penetrating the tropopause. It was noticed when violent thunderstorms passed near an array that a coherent signal would be detected coming from the same direction as the storm. By correlating the measurements with visual, satellite, and Doppler radar observations, the characteristics of the storm could be studied to determine what type of storm would cause the production of infrasound. Most of the storms that would produce an infrasonic signal were the strong supercell-type storms that produced intense gust fronts and tornadoes. More recent measurements at frequencies above 0.1 Hz have been associated with tornadoes and tornadic storms. Following on these observations, NOAA established an infrasonic network to evaluate the use of infrasound for tornado detection and warning. This network has operated since 2003 and is still being optimized and evaluated. This talk will cover the studies that have been conducted and numerical models developed to try and explain this phenomenon.