bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in vocal tract resonance during a pitch cycle
Authors: Takemoto Hironori , Kitamura Tatsuya , Adachi Seiji
Published: October 2013

Vocal tract (VT) resonances during a pitch cycle were examined using area functions of the five Japanese vowels extracted from MRI data of a male subject. The volume-velocity distribution within the VT at each formant was calculated by a transmission line model, as a function of the glottal area. Our previous study showed that in glottal closure condition the fourth formant was provided by the laryngeal cavity (LC) and the other formants by the VT excluding LC, the VT proper (VTp). During the early stage of glottal opening, the fourth formant disappeared, as it had been provided by the closed-tube resonance of LC. After glottal opening, the single volume-velocity node of the first formant moved to the middle pharynx, shortening the effective VT length and thus increasing its frequency. At the other formants, a node appeared at the junction between LC and VTp, and the VT resonance during the glottal opening condition could therefore be approximated by the VTp. This result indicates that the VTp was responsible for most of the VT resonances throughout a period, while LC provided the fourth formant in the glottal closure period. [Work supported by NICT and MEXT KAKENHI of Japan.]
Spectral characteristics of period doubled phonation
Authors: Kreiman Jody , Gerratt Bruce R.
Published: October 2013

Period doubling (also called subharmonic phonation, bifurcated phonation, F0 series) occurs frequently in both pathological and normal phonation. In this kind of phonation, the most obvious acoustic characteristic is that vocal pulses appear in pairs, with alternate pulses differing in period and often in amplitude. Attempts at modeling period doubling by varying period and amplitude did not capture its characteristic quality, leaving the question of which acoustic variables underlie our perception of period doubling. Acoustic analyses of 50 period doubled voices were undertaken to determine what acoustic features might underlie the constant percept associated with period doubling. Every voice examined did show alternation between short/long and large/small glottal pulses. However, alternations in amplitude were not consistently linked to alternations in period. Voices additionally showed a consistent pattern of alterations in pulse shape, so that the A and B pulses consistently differed in H1-H2. Results suggest that the consistent vocal quality associated with period doubling is due to combined alternations in period and spectral tilt. Amplitude alternations appear to be acoustic artifacts of the period and spectral alternations.
Validity of the Nasometer measuring the temporal characteristics of nasalization
Authors: Bae Youkyung , Kuehn David P. , Ha Seunghee
Published: October 2013

Patients with oral-nasal resonance imbalance may present different characteristics not only in the amplitude but also in the temporal aspects of nasalization. Although nasalance has been the most commonly derived measure from the Nasometer (KayPENTAX), the Nasometer also might be useful in providing another important measure, time. Such measurements, however, should be validated in relation to a separate external criterion procedure. This study examined the validity of the Nasometer measuring the temporal characteristics of nasalization. Fourteen adult American English speakers produced three rate-controlled nonsense speech samples: /izinizi/, /azanaza/, and /uzunuzu/. Acoustic data recorded through the Nasometer were compared to those recorded through a standard audio recording setup which served as an external criterion procedure. Four timing variables pertinent to nasalization were measured from the digitized acoustic signals: nasal onset, nasal consonant, nasal offset, and total nasalization. No significant differences were found between the two instrumental conditions in any of four timing variables measured, which suggests the Nasometer can be used as a valid tool to measure the temporal features of nasalization. This study also provided a valid way of segmenting speech tasks using the Nasometer and confirmed the significant effect of different vowel contexts on the temporal characteristics of nasalization.
Pitch determination and sinusoidal modeling for time-varying voiced speech
Authors: Ito Masashi , Yano Masafumi
Published: October 2013

A voiced speech signal consists of sinusoidal components of which amplitude and frequency are time varying. Usually the signals are analyzed by assuming that they are stationary within a local analysis window, so they include inevitable errors. To solve this problem, we have proposed a method termed local vector transform (LVT), in which amplitude and phase of the sinusoidal components were approximated by quadratic functions uniquely determined from input spectrum. Two types of experiments were carried out to evaluate the validity of this method. First, time-varying pitch frequencies (F0s) of natural utterances were investigated. F0 determined by LVT greatly improved the accuracy compared to the conventional pitch determination algorithms: cepstrum, autocorrelation, and instantaneous frequency estimation. Second, LVT is applied to the sinusoidal modeling and the amplitude and phase were estimated for every component. The results apparently showed that the signal obtained by LVT was very close to the input. This was quantified by a signal to residual power ratio (S/R). For both of synthesized and naturally uttered speech signals, LVT showed the higher S/R compared to the conventional algorithm. These results indicate that the proposed algorithm is highly effective for pitch determination and sinusoidal modeling for time-varying speech signals.
Concurrent speech disturbs word generation: Semantic, associative, and grammatical processes in picture naming: A pictureword interference study
Authors: Watanabe Masumi , Kakehi Kazuhiko , Arciuli Joanne , Vinson David , Vigliocco Gabriella , Iwasaki Noriko
Published: October 2013

In pictureword interference (PWI), a picture of an object to be named is presented with a distracter word. Most PWI studies showed semantic interference between a target picture and distracter word (noun). Recently, Vigliocco et al. (2005) studied grammatical effect in naming a picture of action. They found that generation of an inflected form of an Italian verb was disturbed by a distracter in the same grammatical class. In experiment 1 of the present study, naming an object with an auditorily presented noun or verb distracter in Japanese was investigated, and grammatical class but not semantic effect was found, which is incongruent with previous findings. Analyzing the distracters revealed that familiarity of the verbs was lower than that of nouns, and half of nouns classified as semantically close were associative (e.g., garage versus car). In experiment 2, familiarity was matched across distracters, and association effect was examined separately. To see time course of interference, stimulus onset asynchrony (SOA) was changed from −300 to +200 ms. Again, grammatical effect was observed, and associative as well as semantic effect was found for negative SOAs. Possible factors producing grammatical and associative effects in PWI will be discussed cross-linguistically.
Frequency modulated feedback of ones own voice can cause dysfluence of speech
Authors: Yizhong Xu , Toyomura Akira , Koyama Sachiko , Kuriki Shinya
Published: October 2013

Delayed auditory feedback (DAF) can cause speech dysfluency (e.g., stuttering) in healthy normal subjects. In previous studies, feedback frequency was changed linearly or to a constant value in FAF. In this study, we introduce frequency-modulated feedback of pitch in a sine-wave manner. The modulation depth of pitch (F0) of auditory feedback voice was six semitones, and the modulation frequencies of sinewaves were set at 0.05, 0.1, 0.5, 0.9, 2, 4, 6, 8, 10, 12, 14, and 16 Hz. In addition to the FAF experiment, we conducted DAF experiments with delay times of 50, 200, and 400 ms. Participants (18 Chinese and 18 Japanese) were instructed to read sentences as they listened to the altered feedback voice through a headphone under each condition. Speech dysfluency was apparent under all FAF and DAF conditions for both groups. Only when the modulation frequency was 14 Hz did Chinese subjects show significantly larger disturbance than Japanese in FAF. A significant greater disturbance of Chinese in DAF was observed when the delay time was 50 ms. These results indicate that frequency modulation can cause speech dysfluency, as does DAF. [Work supported by the 21st century COE (Center of Excellence) Program.]
Numerical and experimental investigations of transformations of near-field to far-field scattering measurements
Authors: Fawcett John A. , Sildam Juri , Trevorrow Mark V.
Published: October 2013

Due to the size of a target and measurement constraints, the measurements of monostatic acoustic scattering are often made in the near field of the target. For many applications, it is an estimate of the far-field target scattering strength, which is desired. In this presentation some model-based inversion techniques, which can be used to predict far-field monostatic target strengths as a function of aspect angle, are derived. In particular, a set of near-field measurements is used in an inversion scheme to compute coefficients for either a linear array of point scatterers or for a generalized Kirchhoff model of the target. The resulting model is then used to predict the far field scattering amplitudes. Simulated and experimental data are used to illustrate the accuracy of the proposed methods.
Scattering in swell-contaminated seas: A semiempirical approach
Authors: Gauss Roger C. , Fialkowski Joseph M.
Published: October 2013

Acoustic scattering from the undersea air-sea interface is driven by its surface roughness. In modeling this scattering, 2-D spectral models such as the Pierson-Moskowitz model are used to represent the roughness contribution. However, these spectral models typically assume fully developed wind-driven seas. In practice, seas are not always fully developed and swell is often present. In general, scattering depends on the full roughness spectrum and so can be sensitive to its peak behavior. This paper describes low-to-midfrequency (<10 kHz) bistatic scattering strength and coherent surface-loss models that are acoustically constrained by backscatter data and oceanographically constrained by coincidentally measured wave spectra. To match the latter, a semiempirical surface-wave spectral model is developed whose key parameters (strength, exponent, and peak) are expressed solely in terms of significant wave height and wind speed. It is shown that including the non-wind-wave contributions is essential to accurately modeling interface scattering in general at low frequencies, and forward scattering at all frequencies. [Work supported by ONR and PEO C4I & Space (PMW-180).]
Modeling reverberation time series for shallow water clutter environments
Authors: LePage Kevin D. , Holland Charles W. , Neumann Peter
Published: October 2013

The phenomenon of clutter in shallow water environments can be modeled from a variety of viewpoints. One approach we have taken is to model reverberation time series for heterogeneous environments with a variety of scattering mechanisms to see if some of the characteristics of resulting estimates model the characteristics of experimentally observed clutter. Here we show reverberation time series estimates for the Straits of Sicily that seem to capture some of the clutter behavior observed during the Boundary 04 experiment conducted in conjunction with the NATO Undersea Research Centre. Of particular interest is the appearance of coherent time-frequency striation patterns in both the modeled and observed reverberation, with compact time supported but broadband clutter features superimposed by the presence of environmental discontinuities. [Work supported by ONR Phase II STTR N00014-04-C-0399.]
How can auditory presence be generated and controlled?
Authors: Morimoto Masayuki
Published: October 2013

This paper reviews key results of many listening tests on auditory presence, especially auditory localization (AL) and auditory spatial impression (ASI) by the author. The author gave the first demonstration that AL in any direction can be simulated through two loudspeakers using head-related transfer functions (HRTFs). However, individual differences in HRTFs affect the accuracy of AL. It is basically possible to localize sound images in any direction using median-plane HRTFs combined with interaural differences. Furthermore, HRTFs can be simplified by the combination of only some spectral peaks and notches. Meanwhile, the author demonstrated that ASI comprises at least two perceptual components. One is auditory source width (ASW), defined as the width of a sound image fused temporally and spatially with the direct sound image. The other is listener envelopment (LEV), which is the degree of fullness of sound images around the listener, excluding the sound image composing ASW. A listener can perceive these two components separately. The perception of ASW and LEV has a close connection with the law of the first wavefront. Acoustic components under the upper limit of the law contribute to ASW, and acoustic components beyond the upper limit of the law contribute to LEV.
Numerical determination of scattering coefficients of wall surfaces for geometrical room acoustic simulation
Authors: Sakuma Tetsuya , Kosaka Yoshiyuki , Tachioka Yuki
Published: October 2013

There exist a dozen geometrical room acoustic simulation programs which include scattering coefficients of wall surfaces to generate more realistic sound energy reflection. In the light of this utilization, a measurement method of the random-incidence scattering coefficient has been recently standardized by ISO 17497-1, while a numerical technique with BEM is developed to determine the scattering coefficient. First, one case study is done to investigate the behavior of scattering performance of periodical surfaces with sinusoid, triangles and rectangles, with changing the height of surface roughness. As a result, it is seen that the height-to-period ratio of about 30% maximizes the scattering coefficient in the range of middle and high frequency. Second, another case study of geometrical room acoustic simulation is done for a rectangular room composed of uneven reflective walls and absorptive ceiling and floor. Geometrical simulation is performed on a variety of conditions with changing the scattering coefficient, and the reverberation times simulated are compared with those given by wave-based simulation at every octave bands. From the correspondence in reverberation time, the scattering coefficients of the walls are estimated, and its frequency characteristics are compared with those given by the former numerical determination.
Assessing marine mammal abundance, density and habitat use with acoustics
Authors: Gisiner Robert
Published: October 2013

Counting marine mammals is challenging: when seen they usually cannot be heard, and when heard they usually cannot be seen. Both methods miss some fraction of the population, but how does one reconcile two sampling methods that are uncalibrated themselves and will be difficult to calibrate against each other? Three approaches to calibration are reviewed. The one-way calibration approach treats one method as correct and derives a correction function for estimating population data from the other method. The parallel independent approach derives sources of error for each method independently and then compares population estimates: close agreement would strengthen confidence in both methods. The concurrent approach attempts to reconcile each visual detection to an acoustic detection and vice versa, with estimated total numbers derived from the intersection of the two sets. Examples of each method will be provided to illustrate the challenges and potential of each approach.
An archive of odontocete sounds for automatic call recognition
Authors: Mellinger David K. , Nieukirk Sharon L. , Heimlich Sara L.
Published: October 2013

Acoustic remote monitoring using automatic detection of cetacean sounds is becoming widely used to study species’ seasonal distributions and to monitor and mitigate human impacts on cetaceans. To date, most work on automatic detection has focused on baleen whales and a handful of odontocetes, principally sperm whales and harbor porpoises. To further the development of detection methods for other odontocetes (particularly beaked whales, which have become the focus of much interest), it would be helpful to have standardized training and testing datasets. In preparing such datasets, several questions must be addressed: What recordings are available? How certain are the species IDs for these, and how should differing levels of certainty be handled? What is the recording quality? How should recordings be presented and annotated to make them most useful for automatic detection research? Are there any recordings known to be made on-axis with respect to the animal? How are multiple overlapping animals handled? How are mixed-species groups handled? Are data needs different for clicks and whistles? What metadata will be most useful for detection? For localization? How should recordings and metadata be stored and made them available on the net? Partial or full solutions to these questions will be presented.
A broadband acoustic system for resonance classification of swimbladder-bearing fish
Authors: Stanton Timothy K. , Chu Dezhang , Jech J. Michael , Irish James D.
Published: October 2013

A commercial system originally designed for surveying the seafloor has been adapted for measuring the swimbladder resonance of swimbladder-bearing fish. The new towed system has three broadband active acoustic echosounders with nearly continuous coverage of the frequency band 2–110 kHz (with some gaps). The lower frequency bands are used for measuring the resonance, while the highest band can detect zooplankton. A pulse-compression approach (cross correlating the transmit waveform with the echoes) is used to exploit the bandwidth through significantly improving the range resolution to 20, 10, and 2 cm (low-, med-, and high-frequency bands, respectively). The system has been successfully deployed as deeply as 200 m and observed resonances at approximately 3 kHz for herring. Because of the 10–20-cm range resolution at the low frequencies, fish near the towbody could be resolved from one another and fish swimming within 1 m of the seafloor could be distinguished from the seafloor. This system is compared with previous approaches of measuring swimbladder resonance. The potential of the resonance classification method for significantly reducing ambiguities associated with interpreting acoustic echo data compared with traditional high-frequency narrow-band systems (10’s to 100’s of kHz) is discussed.
Enhancement of recombinant tissue-plasminogen activator (rt-PA) activity with 2-MHz transcranial Doppler ultrasound
Authors: Porter Tyrone M. , Holland Christy K. , Meunier Jason M. , Shaw George J.
Published: October 2013

A video microscopy technique was developed to monitor the lytic activity of recombinant tissue plasminogen activator (rt-PA) in combination with 2-MHz transcranial Doppler ultrasound (TCD). Human whole blood clots formed on silk sutures were treated with TCD pulses alone [pulse length=10 cycles, pulse repetition frequency (PRF)=10.5 kHz, Pneg=0.18−0.47 MPa], rt-PA alone (3 μg/ml), and rt-PA with TCD pulses in human fresh frozen plasma for 30 min. An inverted optical microscope was used to acquire images of the clot during treatment. The extent of clot lysis was determined by assessing clot width as a function of time. The average percent change in clot width at 30 min was comparable (∼25%) for clots treated with rt-PA and TCD pulses for all output pressures. However, the initial lytic rate (within the first 5 min) was directly related to the TCD pressure output. The initial lytic activity of rt-PA and 2-MHz TCD pulses (Pneg=0.18 MPa, PRF=10.5 kHz, duty cycle=13%) was similar to the initial lytic activity of rt-PA and 120-kHz ultrasound pulses (Pneg=0.18 MPa, PRF=1667 Hz, duty cycle=20%).
Ultrasound and biodegradable nanoparticles for anticancer drug and gene delivery
Authors: Esenaliev Rinat , Chumakova Olga , Cicenaite Inga , Chakrabarty Shilla , Evers Mark , Andreev Valery
Published: October 2013

Poor penetration of macromolecular drugs and genes in tumor cells substantially limits efficacy and safety of cancer chemo- and biotherapy. Cavitation induced by interaction of ultrasound with nanoparticles accumulated in tumors due to the enhanced permeability and retention effect may provide efficient drug and gene delivery in tumor cells. Biodegradable polymer (PLGA) air-filled nanoparticles manufactured in our laboratory were used for enhancement of drug and gene delivery in vitro and in vivo in human breast, prostate, or ovarian tumors of nude mice (two tumors in each animal). Our specially designed confocal ultrasound system allowed for irradiation and cavitation detection in vitro and in vivo. It was found that the nanoparticles substantially decrease cavitation threshold and increase cavitation activity in vitro and in vivo. Moreover, we obtained three-fold increase of tumor cell transfection in vivo compared to non-irradiated control tumors of same mice. Substantial tumor necrosis was achieved when macromolecular anticancer drug anti-IGFBP-2 was used in combination with the nanoparticles and ultrasound. Our results indicate that biodegradable polymer nanoparticles and ultrasound can be used for enhancement of drug and gene delivery in tumors. [These studies were supported by the DoD Prostate Cancer Research Program (Grant No. W81XWH-04-1-0247) and Breast Cancer Research Program (Grant No. DAMD17-01-1-0416).]
Modeling prosody in speech processing
Authors: Liu Yang
Published: October 2013

Prosody is an important aspect of speech. In spoken language processing, effective prosody modeling helps to identify additional information beyond words (i.e., ‘‘how it is said’’ instead of ‘‘what is said’’) and thus better understand speech. In this talk, we will discuss how prosodic information is utilized in various speech processing tasks. Prosodic features are extracted to represent duration, pitch, and energy, with different normalization, and modeled using machine learning techniques. Research has shown that prosody provides valuable information for tasks such as automatic identification of important events in spoken language (e.g., sentence boundaries or punctuation, disfluencies, discourse markers, topics, and emotions in dialog). These phenomena are important for enriching speech recognition output and helping downstream language processing modules. Modeling prosodic variation across speakers is also useful for these tasks, as well as for developing speaker recognition systems. Additionally, some issues in machine learning techniques in prosody modeling will be discussed. Understanding how prosody is used to signal interesting events in speech will help to build better synthesis models for generating more natural and expressive speech.
Realization of rhythmic dialogue on spoken dialogue system using paralinguistic information
Authors: Fujie Shinya , Kobayashi Tetsunori
Published: October 2013

Paralinguistic information recognition and its application to spoken dialogue system are discussed. Paralinguistic information brings various useful cues that cannot be obtained from linguistic information. The system may know, for example, who should speak next, how the user really feels, and so on. In this paper, we implement several paralingusitic information recognition systems, such as prosody-based attitude recognition system, back-channel feedback generation/recognition system, head gesture recognition system, and so on. Finally, we combine them into the spoken dialogue system on the humanoid robot, and realize a rhythmic dialogue.
Synchronized time-reversal focusing with application to virtual array formation, beam forming, and remote imaging
Authors: Walker Shane C. , Roux Philippe , Kuperman W. A.
Published: October 2013

By sampling and time reversing the field from a distant probe source, a time-reversal mirror (TRM) can produce an intense acoustic focus at the probe source location. Extending this idea to a collection of sources, this work demonstrates that a TRM can generate a virtual array at a downrange location, which can act as a remote platform for time delay beam forming and other coherent wavefront techniques useful for imaging in the vicinity of the virtual array. The technique requires no a priori information about the environment, only the knowledge of the source fields and a means for synchronizing them. In one promising application the TRM is used to coherently image an extended region around a distant passive array. The geometry of the source array is arbitrary. Recent advances in self-adaptive acoustic Green’s function determination may provide opportunities to apply this method without need for a source array. Simulation and experimental results are discussed.
The application of boundary integral equation methods to the numerical calculation of transient waves in rooms
Authors: Kawai Yasuhito
Published: October 2013

The boundary integral equations derived from Kirchhoff’s formula and its normal derivative form are available for the numerical calculation of transient waves in rooms. The two equations are compared in view of the stability and accuracy in the numerical calculation of responses in a rigid cubic room in which rigorous responses can be obtained by the image method. Some source waves and some problems appear in the numerical implementation such as the singular integrals, and the treatment of absorbent surfaces is also investigated. Finally, it is shown that the boundary integral equation method is a powerful tool to obtain transient waves in rooms.
Fogg Art Museum lecture room: A calibrated recreation of the birthplace of room acoustics
Authors: Katz Brian F. G. , Wetherill Ewart A.
Published: October 2013

At the end of the 19th century, Wallace Clement Sabine undertook the task of correcting the acoustics of the Fogg Art Museum lecture hall. His work on this acoustically difficult (semi-circular, domed, arched) auditorium was the basis for his monumental work on reverberation time and absorption, beginning the science of room acoustics as it is now known. The room underwent various renovations over 70 years, concluding with its demolition in 1973. Just prior to this event, one author was fortunate to have measured several room impulse responses. Through the use of architectural plans and the few existing photos, a computational room acoustical model was created. This model was calibrated using the historically important measurements as a reference. The geometrical model incorporates the room’s various architectural phases. Using computer auralizations, the room is now accessible in acoustical terms, with the ability to ‘‘perience’’ an educated rendering of the acoustics of the room as Sabine found it in 1895. The results of this study, particularly the geometrical model, are intended for public use and are made generally available for room acoustics students and researchers who chose to follow in Sabine’s footsteps (www.catt.se/FoggArtMusum.htm). Portions of this presentation were presented at Forum Acousticum 2005.
A comparison of computer modeling auralization and binaural room recordings for a multipurpose high school auditorium utilizing an orchestral shell, overhead panels, and clouds.
Authors: Freiheit Ron
Published: October 2013

The development of auralization techniques has provided a new method to demonstrate potential acoustical benefits of changes in design or the application of acoustic treatments in specific spaces. It’s useful to compare the results from the auralization process with actual binaural recordings in the physical space to discover similarities and differences. A typical high school proscenium-style, multipurpose auditorium was modeled, including an orchestral shell, overhead panels, and clouds. Auralizations were made of the auditorium at various locations in the audience area and on stage, with and without the shell and overhead panels, in place. These were compared with binaural recordings made at the same locations within the auditorium. Auralization metrics will be compared with the binaural recordings, highlighting the changes made with the shell and overhead panels in place, along with the similarities and differences between the two methods.
Real-time audio rendering system for virtual reality
Authors: Lentz Tobias , Schroeder Dirk , Behler Gottfried K. , Vorlaender Michael
Published: October 2013

Systems of virtual acoustics are more and more coming into the focus of research and application. Creating a virtual sound scene with spatially distributed sources requires a technique for adding spatial cues to audio signals and an appropriate reproduction. A real-time audio rendering system is introduced that combines room acoustics, dynamic crosstalk cancellation, and multitrack binaural synthesis for virtual acoustical imaging. The room acoustics component takes into account the full up-to-date algorithmic approach of specular reflections and scattering, but with real-time processing. The real-time performance of the software was reached by introduction of a flexible framework for the interactive auralisation of virtual environments. The concept of scene graphs for the efficient and flexible linkage of autonomous-operating subscenes by means of so-called portals has been incorporated into the existing framework, combined with an underlying BSP-tree structure for processing geometry issues very fast. Using this framework enables a significant reduction of computation time for both applied algorithms (deterministic image sources and a stochastic ray tracer). This enables the simulation of indoor or outdoor spatial distributed sources and, in addition to that, near-to-head sources for a freely moving listener in room-mounted virtual environments without the use of headphones.
Theoretical analysis of statistical properties of the sound-pressure field and sound energy density field in rectangular enclosures
Authors: Xu Buye , Sommerfeldt Scott D.
Published: October 2013

The sound-pressure field and sound energy density (ED) field for rectangular enclosures are obtained theoretically by solving the Helmholtz equation and Euler’s equation with low-energy absorption boundaries. Based on those results, both analytic and numerical methods are applied to compute some statistical properties. The results of the statistical analysis show that the spatial variation of the ED field is generally much less than that of the pressure field in reverberant enclosures. In addition, a modified ED quantity is developed and will be discussed.
An automated approach to detecting pulsive gray whale (Eschrichtius robustus) vocalizations within acoustic data to estimate call rate changes over time in Laguna San Ignacio
Authors: Guerra Melania , Thode Aaron M. , Dahlheim Marilyn E. , Urban Jorge , Koltz Amanda M.
Published: October 2013

Acoustic recordings of type 1b gray whale calls were made in San Ignacio Lagoon, during the wintering months of 2005 and 2006 when these animals were present to breed and raise calves. A collection of horizontal, bottom-mounted arrays containing two or three elements monitored the mouth of the lagoon over consecutive days, targeting vocalizations below 1 kHz. Because these pulsive calls are highly variable in the timing and number of pulses, standardized detection methods involving matched-filtering or spectrogram correlation have been unsuccessful. A sequence of automated procedures programed in matlab and ishmael was implemented to assist with the detection of calls within the dataset. Simple manual recognition based on human judgment was also performed on the shorter time series to serve as an independent check. Results for hourly call rates were computed for both seasons individually. A similar such acoustic dataset had been previously collected by Dahlheim (1987) in the years 1982–84 and analyzed manually. This dataset would be digitized and examined with the new automated analyses in order to compare changes in average call rates over the two-decade interval. A rough relationship with animals present can be drawn, as census numbers are available for both periods.
Variation in sound production in relation to behavior of bottlenose dolphins (Tursiops aduncus)
Authors: Lemon Michelle , Cato Douglas H. , Lynch Tim P. , Harcourt Robert G.
Published: October 2013

Dolphins are social animals that inhabit an opaque environment where visual cues are often limited, thus acoustic signals play an important role in inter- and intragroup communication. Phonations may be used to signal conspecifics, in navigation, or in the detection of prey, and may vary with behavior, environmental conditions, or geographic location. Variation in the acoustic and surface behavior of two geographically separated and genetically differentiated populations of bottlenose dolphins in Southeastern Australia were investigated over a 3-year period. Two hypotheses were tested: (1) vocal repertoire varies with behavior; and (2) variation in vocal repertoire may have arisen due to geographic isolation. Overall rate of sound production by the dolphins was similar in each field site but varied significantly with behavioral activity. Call rates were highest with behavior that involved increased arousal, such as socializing and foraging. Whistle rates and the duration of echolocation click bouts were similar for each location, however, burst-pulsed sounds varied significantly with behavioral state and between the field areas. This difference may relate to differences in social behavior between populations and be driven by variability in social structure and environmental conditions. [Research supported by Australian Geographic, PADI Foundation and Macquarie University.]
Standard-target calibration of active sonars used to quantify aquatic organisms
Authors: Foote Kenneth G.
Published: October 2013

The span of sonars being calibrated by the standard-target method continues to grow. In this retrospective of the past 25 years, the essence of the method is reviewed for both narrow-band and broadband systems. Applications to scientific echo sounders with operating frequencies from 18 kHz to 3.2 MHz are summarized. Applications to multibeam sonars that provide the water-column signal, with frequencies of 90, 200, 240, and 400 kHz, are also summarized. A planned application to a parametric sonar, with primary frequencies in the range 15–21 kHz and difference-frequency band 0.5–6 kHz, is described. The method is applicable to ordinary midfrequency sonars. In each example, particular standard targets are specified. Diameters vary from 10 mm for a sphere of tungsten carbide with 6% cobalt binder for use at low megahertz frequencies, to 60 mm for a sphere of electrolytic-grade copper for use at 38 kHz, to 280 mm for a sphere of aluminum alloy for use at low-kilohertz frequencies.
Acoustic identification and density estimate of Diaphus theta (myctophidae) off Hokkaido, Japan
Authors: Yasuma Hiroki , Miyashita Kazushi , Yamamura Orio
Published: October 2013

Diaphus theta is the most abundant micronektonic fish in the northwestern Pacific. Field acoustic data and biological samples were obtained both day and night off of eastern Hokkaido, Japan in September 2006 to estimate the fish density and diel changes of its vertical distribution. Differences of acoustical target strength (TS) values between at 38 and 120 kHz were applied to identify D. theta echos using field echo data. Theoretical estimation using swimbladder acoustic scattering models showed that the TS difference (TS 120-38 kHz) of larger fishes (over 60 mm) was between −4 and 1 dB; that for smaller fishes (less 60 mm) was less than .4 dB. These values differed from those of other major component species of the deep-scattering layer, such as krill and pollock, suggesting that the echo from D. theta is acoustically identifiable. Diel vertical distributions of D. theta were estimated after identification. Relatively dense schools were observed at around 400-m depth during daytime, although the schools were scattered widely above 100-m depth during nighttime. These results matched those obtained by biological sampling. In the surface layer (above 100 m), the estimated fish densities were about tenfold higher at nighttime than in daytime.
Mode processing of transient signals using a deficient vertical receiving array, with application to LOAPEX measurements
Authors: Udovydchenkov Ilya A. , Brown Michael G. , Worcester Peter F. , Dzieciuch Matthew A. , Van Uffelen Lora J. , Mercer James A. , Howe Bruce M. , Andrew Rex K.
Published: October 2013

Mode processing of transient signals in a deep ocean environment using a deficient vertical receiving array is considered. Here, ‘‘deficient’’ implies that the vertical array is too sparse to resolve modes and/or has gaps. It is well known that mode processing of cw signals using a deficient array leads to significant modal cross-talk, i.e., nonzero projections of mode n energy onto mode m, m≠n. It is shown, using simulated wave fields, that when phase-coherent processing is employed, transient signals are less sensitive to modal cross-talk than their cw counterparts. An explanation of this behavior is provided. Mode processing of a subset of the measurements made during the LOAPEX experiment at approximately 1 Mm range with f0=75 Hz, Δf=35 Hz is shown to give robust estimates of modal group time spreads for mode numbers 0≤m≤70. [Work supported by ONR.]
Horizontal coherence of tracked arrivals in the North Pacific Acoustic Laboratory98 (NPAL98)
Authors: Dzieciuch Matthew A. , Vera Michael D. , NPAL Group The , Colosi J. A. , Cornuelle B. D. , Dushaw B. D. , Howe B. M. , Mercer J. A. , Munk W. H. , Spindel R. C. , Worcester P. F.
Published: October 2013

The NPAL98 experiment offered a unique opportunity to study horizontal coherence because of the deployment of a billboard array. The billboard consisted of five vertical line arrays with a 3600-m horizontal aperture listening to a 75-Hz acoustic signal 3500 km away. Original estimates of horizontal coherence were complicated by the bottom-interacting sound field, which made it difficult to track individual arrivals. Thus, previous studies of the horizontal coherence in this experiment were limited to the arrival pattern in aggregate. By using a turning-point filter and a rake correlator, it is now possible to track individual arrivals during the NPAL98 experiment. We can thus measure the coherence of individual early non-bottom-interacting arrivals. Results are compared to recent calculated predictions using both Monte Carlo and path-integral methods for the same environment. [Work supported by ONR.]
The range evolution of the mean wavefront intensity for the long-range ocean acoustic propagation experiment (LOAPEX) off-axis source transmissions
Authors: Xu Jinshan , Colosi John A. , Mercer James A. , Howe Bruce M. , Andrew Rex K. , Worcester Peter F. , Dzieciuch Matthew
Published: October 2013

One of the main objectives of the NPAL 2004 experiment, LOAPEX (Long-range Ocean Acoustic Propagation EXperiment), which was conducted between 10 September and 10 October 2004, was to better understand the roles of scattering and diffraction in general. The LOAPEX measurement provided acoustic transmission data for ranges of 50, 250, 500, 1000, 1600, 2300, and 3200 km. By placing the source off-axis in order to avoid exciting low-order modes, we are able to study phenomena of the significant in-filling of acoustic energy into the finale region. Our focus will be on the transmissions for the off-axis source location (nominally 350-m depth), and the acoustic receptions as recorded on the 1400-m-long axial receiving array. The observation of the mean intensity of the wavefront arrival pattern at each range will be compared to deterministic ray and parabolic equation calculations. The following questions will be addressed here: (1) How does high angle acoustic energy from an off-axis source transfer energy to low angles in the axial region of the waveguide? (2) What are the relative contributions from diffraction and scattering? (3) How does this energy transfer scale with range? [Work supported by ONR.]
From laboratory to clinical trials: An odyssey of ultrasound inverse scattering imaging for breast cancer diagnosis
Authors: Johnson Steven A. , Borup David T. , Wiskin James W. , Berggren Michael , Hanover Barry , Setinsek Frank , Olsen Scott , Callahan Karleen
Published: October 2013

Techniscan has completed a local phase of clinical trials of a unique inverse scattering breast cancer scanner. The scanner is based on transmission of plane waves from 0.3 to 2 MHz through the breast to a receiver on the opposite side of the breast. The receiver consists of a 2-D array of six rows by 160 columns. These elements are multiplexed by a factor of 12 into 80 analog to digital converters. The dual transducer-head design allows the inversion of the transmission data to create two independent quantitative images, one of speed of sound and a second of attenuation. The two heads are mechanically attached to a hollow rotating shaft, to provide 360 deg of mechanical motion. Typically, 180 to 360 steps per 360-deg rotation and 2-mm vertical steps are used to create a data set that is inverted into a 3-D image of 240 by 240 by 70 voxels. A unique set of custom circuit boards was constructed to implement scanner electronics. The next scanner version with anticipated inverse scattering resolution of 1 mm or less and reflection tomography resolution of 0.5 mm or less should improve performance. Clinical images to date and performance will be discussed.
Whole breast imaging with ultrasound tomography: First clinical results at the Karmanos cancer institute
Authors: Duric Neb , Littrup Peter , Holsapple Earle , Rama Olsi
Published: October 2013

Although mammography is the gold standard for breast imaging, it leads to a high rate of biopsies of benign lesions and a significant false negative rate for women with dense breasts. A clinical breast-imaging device, based on the principles of ultrasound tomography, is being developed in response to this imaging performance gap. The computed ultrasound risk evaluation (CURE) system has been designed with the clinical goal of providing fast, whole-breast, operator-independent imaging, capable of differentiating breast masses. In an initial assessment of its in vivo performance, 50 patients were examined with CURE. The following results were demonstrated: (i) tomographic imaging of breast architecture, (ii) in-plane spatial resolution of 0.5 mm in reflection and 4 mm in transmission, (iii) imaging of breast masses in reflection and transmission mode (sound speed and attenuation, and (iv) differentiation of breast masses was shown to be feasible. These initial results indicate that operator-independent, whole-breast imaging and the detection and characterization of breast masses are feasible. Future studies will focus on improved detection and differentiation of masses with the long-term goal of improving the specificity of breast exams. [The authors acknowledge financial support from the Karmanos Cancer Institute and the NIH (grant R43 CA108072-01).]
Advanced tomographic algorithms and their potential applications to ultrasound imaging
Authors: Pan Xiaochuan , LeRoque Samuel , Sidky Emil , Anastasio Mark
Published: October 2013

The success of computed tomography has led to the development of a wide variety of tomographic imaging techniques. There has always been a great interest in ultrasound-based tomographic imaging because it can provide detailed, quantitative information about the imaged subject, which can be used for diagnosis, evaluation, and monitoring of cancer and other diseases. Tomographic imaging relies not only upon the imaging system for data acquisition but also upon the algorithms for image recovery from the data. In the last decade or so, there has been a tremendous development of innovative algorithms for tomographic imaging. One important breakthrough is that an artifact-free ROI image within the subject can be obtained from, e.g., truncated data. This breakthrough has led to the development of the so-called targeted-ROI imaging strategy in which one can substantially reduce imaging effort and artifacts. There have also been significant advances in reconstructing images from highly incomplete data acquired, e.g., at a small number of views and/or over a limited angular range. In this paper, we will discuss these new developments and their potential applications to ultrasound-based imaging. We will use examples to illustrate how they can be exploited for reconstructing images in different types of ultrasound-based tomographic imaging.
Full wave nonlinear inverse scattering for transmission breast imaging
Authors: Wiskin James , Borup David , Johnson Steven
Published: October 2013

Ultrasound has been proposed as an adjunct diagnostic modality for 25+ years. However, initial studies were hampered by relatively low resolution. Over the past 20 years there has been a tremendous amount of research carried out in inverse scattering, the mathematical foundation behind quantitative determination of the coefficients of a partial differential equation. In particular, the research at TechniScan, Inc., and the Dept. of Bioengineering, Univ. of Utah, has culminated in algorithms that give approximately millimeter resolution, and quantitative accuracy, in 2-D and 3-D problems. We invert the full nonlinear acoustic inverse scattering problem (no Born/Rytov approximation) in 2-D and 3-D. We reconstruct a phantom with known inclusions. The image space is 241×241×135=∼7.8 Megapixels or larger. Each pixel is 0.8×0.8×1.0mm3 in size. The data is collected on a 6 by 160 element array, positioned 180 views surrounding the breast. The transmitted wave is a plane wave chirp. Reconstruction time is ∼2 h on a six-node cluster of Pentium Ms. This paper will discuss theoretical algorithm development, practical issues that result in images, and a device presently being used in a clinical setting. We show several reconstructed images from ∼400 volunteers.
Ultrasonic reflection imaging with a heterogeneous background for breast cancer detection and diagnosis
Authors: Huang Lianjie , Quan Youli , Duric Nebojsa , Li Cuiping
Published: October 2013

Sound speeds and densities of breast tissue vary in space, and those of tumors are different from the surrounding tissues. These differences in mechanical properties cause scattering of ultrasonic waves, particularly in dense breasts. An ultrasonic reflection imaging method using a heterogeneous background is presented to properly account for scattering off heterogeneities within the breast. The method is based on downward continuation of ultrasonic wave fields in the frequency-space and frequency-wave-number domains. Synthetic ultrasonic data for scatterers within a heterogeneous breast model were used to investigate the imaging resolution of the method. Imaging examples using ultrasonic data acquired using a clinical prototype, consisting of an ultrasound scanner with a ring transducer array, are presented. The heterogeneous background sound-speed models were obtained using transmission tomography. The imaging results are compared with those obtained using a homogeneous background. The study demonstrates that imaging with heterogeneous backgrounds significantly improves image quality and resolution. [This work was supported through the DOE Laboratory-Directed Research and Development program at Los Alamos National Laboratory.]