bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of tidal breathing and reiterant speech breathing using whole body plethysmography
Authors: Bonadies Marguerite , Withnell Robert H. , Lulich Steven M.
Published: October 2014

Classic research in the field of speech breathing has found differences in the characteristics of breathing patterns between speech respiration and tidal breathing. Though much research has been done on speech breathing mechanisms, relatively little research has been done using the whole body plethysmograph. In this study, we sought to examine differences and similarities between tidal respiration and breathing in reiterant speech using measures obtained through whole-body plethysmography. We hypothesize that there are not significant differences between pulmonary measures in tidal respiration and in speech breathing. This study involves tidal breathing on a spirometer attached to the whole-body plethysmograph followed by reiterant speech using the syllable /da/ while reading the first part of The Rainbow Passage. Experimental measures include compression volumes during both breathing tasks, and absolute lung volumes as determined from the spirometer and calibrated whole-body plethysmograph. These are compared with the pulmonary subdivisions obtained from pulmonary function tests, including vital capacity, functional residual capacity, and total lung volume.
SIPMI: Superimposing palatal profile from maxillary impression onto midsagittal articulographic data
Authors: Chen Wei-rong , Chang Yueh-chin
Published: October 2014

Palatal traces reconstructed by current advanced technologies of real-time mid-sagittal articulatory tracking (e.g., EMA, ultrasound, rtMRI, etc.) are mostly in low-resolution and lack concrete anatomical/orthodontic reference points as firm articulatory landmarks for determining places of articulation. The present study proposes a method of superimposing a physical palatal profile extracted from maxillary impression, onto mid-sagittal articulatory data. The whole palatal/dental profile is first obtained from performing an alginate maxillary impression, and a plaster maxillary mold is made from the impression. Then, the mold is either (1) cut into halves for hand-tracing or (2) 3D-scanned to extract a high resolution mid-sagittal palatal line. The mid-sagittal palatal line made from maxillary mold is further sub-divided into articulatory zones, following definitions of articulatory landmarks in the literature (e.g., Catford 1988), by referring to anatomical/orthodontic landmarks imprinted on the mold. Lastly, the high-resolution, articulatorily divided palatal line can be superimposed, by using modified Iterative Closet Point (ICP) algorithm, onto the reconstructed, low-resolution palatal traces in the real-time mid-sagittal articulatory data, so that clearly divided places of articulation on palate can be visualized with articulatory movements. Evaluation results show that both hand-tracing and 3D-scanned palatal profiles yield accurate superimpositions and satisfactory visualizations of place of articulation in our EMA data.
Waveform morphology of pre-speech brain electrical potentials
Authors: Smith Silas , Yonovitz Al
Published: October 2014

The inter- and intra-subject variations of the cortical responses before the initiation of speech were recorded. These evoked potentials were obtained at a sufficient sample rate that both slow negative waves as well as faster neurogenic signals were obtained. The marking point for determining the pre-event time epoch has been an EMG source. The data are typically acquired off-line and later averaged. This research uses a vocal signal as the marking point, and displays in real time the event-related potential. Subjects were 12 males and females. Electrodes were recorded with a silver–silver chloride electrodes positioned at Cz and using the earlobes as reference and ground. A biological preamplifier was used to amplify the weak bioelectric signals 100,000 times. Each time epoch was sampled at 20,000 samples/sec. The frequency response of these amplifiers had a high-pass of 0.1 Hz and a low-pass of 3 kHz. One second of these signals were averaged for 100 trials just prior to the subject initiation of the word “pool.” Electrical brain potentials have proven to be extremely useful for diagnosis, treatment, and research in the auditory system, and are expected to be of equal importance for the speech system.
Dialectal variation in affricate place of articulation in Korean
Authors: Kang Yoonjnung , Han Sungwoo , Kochetov Alexei , Kong Eunjong
Published: October 2014

The place of articulation (POA) of Korean affricates has been a topic of much discussion in Korean linguistics. The traditional view is that the affricates were dental in the 15th century and then changed to a posterior coronal place in most dialects of Korean but the anterior articulation is retained in major dialects of North Korea, most notably Phyengan and Yukjin. However, recent instrumental studies on Seoul Korean and some impressionistic descriptions of North Korean dialects cast doubt on the validity of this traditional view. Our study examines the POA of /c/ (lenis affricate) and /s/ (anterior fricative) before /a/ in Seoul Korean (26 younger and 32 older speakers) and in two North Korean varieties, as spoken by ethnic Koreans in China (14 Phyengan and 21 Yukjin speakers). The centre of gravity of the frication noise of /c/ and /s/ was examined. The results show that in both North Korean varieties, both sibilants are produced as anterior coronal and comparable in their POA. In Seoul Korean, while the POA contrast shows a significant interaction with age and gender, the affricate is consistently and substantially more posterior than the anterior fricative across all speaker groups. The results support the traditional description.
An articulatory study of high vowels in Mandarin produced by native and non-native speakers
Authors: Wu Chenhuei , Chen Weirong , Shih Chilin
Published: October 2014

This paper examined the articulatory properties of high vowels [i], [y], and [u] in Mandarin produced by four Taiwanese Mandarin native speakers and four English-speaking Chinese learners (L2 learners) with an Electromagnetic Articulagroph AG500. The articulatory positions of the tongue top (TT), the tongue body (TB), the tongue dorsal (TD), and the lips were investigated. The TT, TB, and TD of [y] produced by the L2 learner were further back than that by the native. In addition, the TD of [y] by the L2 learners was higher than the native. Further comparison found that the tongue positions of [y] was similar to [u] in L2 production. Regarding to the lip positions, the [y] and [u] were more protruded that [i] in the native production, while there is no difference among these three vowels in the L2 production. The findings suggested that most of the L2 learner were not aware that the lingual target [y] should be very similar to [i] but the lip articulators of [y] are more protruded than [i]. Some L2 learners pronounce [y] more like a diphthong [iu] rather than a monophthong.
Production and perception training of /r l/ with native Japanese speakers
Authors: Schmidt Anna M.
Published: October 2014

Visual feedback with electropalatometry was used to teach accurate /r/ and /l/ to a native Japanese speaker. Perceptual differentiation of the phonemes did not improve. A new perceptual training protocol was developed and tested.
Production of a non-phonemic variant in a second language: Acoustic analysis of Japanese speakers’ production of American English flap
Authors: Kitahara Mafuyu , Tajima Keiichi , Yoneyama Kiyoko
Published: October 2014

Second-language (L2) learners need to learn the sound system of an L2 so that they can distinguish L2 words. However, it is also instructive to learn non-phonemic, allophonic variations, particularly if learners want to sound native-like. The production of intervocalic /t d/ as an alveolar flap is a prime example of a non-phonemic variation that is salient in American English and presumably noticeable to many L2 learners. Yet, how well such non-phonemic variants are learned by L2 learners is a relatively under-explored subject. In the present study, Japanese learners’ production of alveolar flaps was investigated, to clarify how well learners can learn the phonetic environments in which flapping tends to occur, and how L2 experience affects their performance. Native Japanese speakers who had lived in North America for various lengths of time read a list of words and phrases that contained a potentially flappable stop, embedded in a carrier sentence. Preliminary results indicated that the rate of flapping varied considerably across different words and phrases and across speakers. Furthermore, acoustic parameters such as flap closure duration produced by some speakers showed intermediate values between native-like flaps and regular stops, suggesting that flapping is a gradient phenomenon. [Work supported by JSPS.]
A comparison of speaking rate consistency in native and non-native speakers of English
Authors: Baese-Berk Melissa M. , Morrill Tuuli
Published: October 2014

Non-native speech differs from native speech in many ways, including overall longer durations and slower speech rates (Guion et al., 2000). Speaking rate also influences how listeners perceive speech, including perceived fluency of non-native speakers (Munro & Derwing, 1998). However, it is unclear what aspects of non-native speech and speaking rate might influence perceived fluency. It is possible that in addition to differences in mean speaking rate, there may be differences in the consistency of speaking rate within and across utterances. In the current study, we use production data to examine speaking rate in native and non-native speakers of English, and ask whether native and non-native speakers differ in the consistency of their speaking rate across and within utterances. We examined a corpus of read speech, including isolated sentences and longer narrative passages. Specifically, we test whether the overall slower speech rate of non-native speakers is coupled with an inconsistent speech rate that may result in less predictability in the produced speech signal.
Design of a coprime array for the North Elba sea trial
Authors: Chavali Vaibhav , Wage Kathleen E. , Buck John R.
Published: October 2014

Vaidyanathan and Pal [IEEE Trans. Signal Process. 2011] proposed the use of Coprime Sensor Arrays (CSAs) to sample spatial fields using fewer elements than a Uniform Line Array (ULA) spanning the same aperture. A CSA consists of two interleaved uniform subarrays that are undersampled by coprime factors M and N. The subarrays are processed independently and then their scanned responses are multiplied to obtain a unaliased output. Although the CSA achieves resolution comparable to that of a fully populated ULA, the CSA beampattern has higher sidelobes. Adhikari et al. [Proc. ICASSP, 2013] showed that extending the subarrays and applying spatial tapers could reduce CSA sidelobes. This paper considers the problem of designing a CSA for the North Elba Sea Trial described by Gingras [SACLANT Tech. Report, 1994]. The experimental dataset consists of receptions recorded by a 48-element vertical ULA in a shallow water environment for two different source frequencies: 170 Hz and 335 Hz. This paper considers all possible coprime subsamplings for this array and selects the configuration that provides the best tradeoff between number of sensors and performance. Results are shown for both simulated and experimental data. [Work supported by ONR Basic Research Challenge Program.]
Wind generated ocean noise in deep sea
Authors: Li Fenghua , Wang Jingyan
Published: October 2014

Ocean noise is an important topic in underwater acoustics, which has been paid much attention in last decades. Ocean noise sources may consist of wind, biological sources, ships, earthquakes and so on. This paper discusses measurements of the ocean noise intensity in deep sea during strong wind periods. During the experiment, shipping density is small enough and the wind generated noise is believed to be the dominated effect in the observed frequency range. The analyses of the recoded noise data reveal that the wind generated noise source has a strong dependence on the wind speed and frequency. Based on the data, a wind generated noise source model is presented. [Work supported by National Natural Science Foundation of China, Grant No. 11125420.]
Ocean ambient noise in the North Atlantic during 1966 and 2013–2014
Authors: Sirovic Ana , Wiggins Sean M. , Hildebrand John A. , McDonald Mark A.
Published: October 2014

Low-frequency ocean ambient noise has been increasing in many parts of the worlds’ oceans as a result of increased shipping. Calibrated passive acoustic recordings were collected from June 2013 to March 2014 on the south side of Bermuda in the North Atlantic, at a location where ambient noise data were collected in 1966. Monthly and hourly mean power spectra (15–1000 Hz) were calculated, in addition to skewness, kurtosis, and percentile distributions. Average spectrum levels at 40 Hz, representing shipping noise, ranged from 78 to 80 dB re: 1 µPa2/Hz, with a peak in March and minimum in July and August. Values recorded during this recent period were similar to those recorded during 1966. This is different from trends observed in the Northern Pacific, where ocean ambient noise has been increasing; however, the location of this monitoring site was exposed only to shipping lanes to the south of Bermuda. At frequencies dominated by wind and waves (500 Hz), noise levels ranged from 55 to 66 dB re: 1 µPa2/Hz, indicating low sea states (2–3) prevailed during the summer, and higher sea states (4–5) during the winter. Seasonally important contribution to ambient sound also came from marine mammals, such as blue and fin whales.
Defining home recording spaces
Authors: Otero Sebastian
Published: October 2014

The idea of home recording has been widely used through out the audio and acoustics community for some time. The effort and investment put into these projects fluctuate in such a wide spectrum that there is no clear way to unify the concept of “home studio,” making it difficult for acoustical consultants and clients to reach an understanding on each other project goals. This paper analyses different spaces which vary in terms of privacy, comfort, size, audio quality, budget, type of materials, acoustic treatments, types of projects developed and equipment, but which can all be called “home recording spaces,” in order to develop a more specific classification of these environments.
Equalization and compression—Friends or foes?
Authors: Case Alexander U.
Published: October 2014

These two essential signal processors have overlapping capabilities. Tuning a sound system for any function requires complementary interaction between equalization and compression. The timbral impact of compression is indirect, and can be counterintuitive. A deeper understanding of compression parameters, particularly attack and release, clarifies the connection between compression and tone and makes coordination with equalization more productive.
Investigate the persistence of sound frequencies Indoor television decors
Authors: Karami Mohsen
Published: October 2014

It seems to add to the décor of the studio and make a half-closed spaces and reduce the absorption of waves hitting the studio sound and lasting changes in the frequency of sound energy absorption occurs. To address this issue, the pink noise playback with B&K2260 device, standard time ISO3382, reverberation time in IRIB channels programs twelve decors was measured in various studios. Survey shows values obtained in all the décor, the persistence of high frequencies and this effect occurred regardless of the décor’s shape and the studio is.
Detection of fish calls by using the small underwater sound recorder
Authors: Matsuo Ikuo , Imaizumi Tomohito , Akamatsu Tmonari
Published: October 2014

Passive acoustic monitoring has been widely used for the survey of marine mammals. This method can be applied for any sounding creatures in the ocean. Many fish, including croaker, grunt, and snapper, produce species-specific low-frequency sounds associated with courtship and spawning behavior in chorus groups. In this paper, the acoustic data accumulated by an autonomous small underwater recorder were used for the sound detection analysis. The recorder was set on the sea floor off the coast of Chosi in Japan (35°40′55″N，140°49′14″E). The observed signals include not only target fish calls (white croaker) but also calls of another marine life and noises of vessels. We tried to extract the target fish calls out of the sounds. First, recordings were processed by bandpass filter (400–2400 Hz) to eliminate low frequency noise contamination. Second, a low frequency filter applied to extract envelope of the waveform and identified high intensity sound units, which are possibly fish calls. Third, parameter tuning has been conducted to fit the detection of target fish call using absolute received intensity and duration. In this method, 28614 fish calls could be detected from the observed signals during 130 hours Comparing with manually identified fish call, correct detection and false alarm were 0.88 and 0.03, respectively. [This work was supported by CREST, JST.]
Plugin architecture for creating algorithms for bioacoustic signal processing software
Authors: Marsh Christopher A. , Roch Marie A. , Mellinger David K.
Published: October 2014

There are several acoustic monitoring software packages that allow for the creation and execution of algorithms that automate detection, classification, and localization (DCL). Algorithms written for one program are generally not portable to other programs, and usually must be written in a specific programming language. We have developed an application programming interface (API) that seeks to resolve these issues by providing a plugin framework for creating algorithms for two acoustic monitoring packages: Ishmael and PAMGuard. This API will allow new detection, classification, and localization algorithms to be written for these programs without requiring knowledge of the monitoring software’s source code or inner workings, and lets a single implementation run on either platform. The API also allows users to write DCL algorithms in a wide variety of languages. We hope that this will promote the sharing and reuse of algorithm code. [Funding from ONR.]
Temporal patterns in detections of sperm whales (Physeter macrocephalus) in the North Pacific Ocean based on long-term passive acoustic monitoring
Authors: Merkens Karlina , Simonis Anne , Oleson Erin
Published: October 2014

Sperm whales (Physeter macrocephalus), a long-lived, cosmopolitan species, are well suited for long-term studies, and their high amplitude echolocation signals make them ideal for passive acoustic monitoring. NOAA’s Pacific Islands Fisheries Science Center has deployed High-frequency Acoustic Recording Packages (200 kHz sampling rate) at 13 deep-water locations across the central and western North Pacific Ocean since 2005. Recordings from all sites were manually analyzed for sperm whale signals, and temporal patterns were examined on multiple scales. There were sperm whale detections at all sites, although the rate of detection varied by location, with the highest rate at Wake Island (15% of samples), and the fewest detections at sites close to the equator (<1%). Only two locations (Saipan and Pearl and Hermes Reef) showed significant seasonal patterns, with more detections in the early spring and summer than in later summer or fall. There were no significant patterns relating to lunar cycles. Analysis of diel variation revealed that sperm whales were detected more during the day and night compared to dawn and dusk at most sites. The variability shown in these results emphasizes the importance of assessing basic biological patterns and variations in the probability of detection before progressing to further analysis, such as density estimation, where the effects of uneven sampling effort could significantly influence results.
Automatic detection of tropical fish calls recorded on moored acoustic recording platforms
Authors: Kaplan Maxwell B. , Mooney T. A. , Partan Jim
Published: October 2014

Passive acoustic recording of biological sound production on coral reefs can help identify spatial and temporal differences among reefs; however, the contributions of individual fish calls to overall trends are often overlooked. Given that the diversity of fish call types may be indicative of fish species diversity on a reef, quantifying these call types could be used as a proxy measure for biodiversity. Accordingly, automatic fish call detectors are needed because long acoustic recorders deployments can generate large volumes of data. In this investigation, we report the development and performance of two detectors—an entropy detector, which identifies troughs in entropy (i.e., uneven distribution of entropy across the frequency band of interest, 100–1000 Hz), and an energy detector, which identifies peaks in root mean square sound pressure level. Performance of these algorithms is assessed against a human identification of fish sounds recorded on a coral reef in the US Virgin Islands in 2013. Results indicate that the entropy and energy detectors, respectively, have false positive rates of 9.9% and 9.9% with false negative rates of 28.8% and 31.3%. These detections can be used to cluster calls into types, in order to assess call type diversity at different reefs.
A comparison of measured and forecast acoustic propagation in a virtual denied area characterized by a heterogeneous data collection asset-network
Authors: Jiang Yong-Min , Alvarez Alberto
Published: October 2014

The fidelity of sonar performance predictions depends on the model used and the quantity and quality of the environmental information that is available. To investigate the impact of the oceanographic information collected by a heterogeneous and near-real time adaptive network of robots in a simulated access denied area, a field experiment (REP13-MED) was conducted by CMRE during August 2013 in an area (70 × 81 km) located off-shore La Spezia (Italy), in the Ligurian Sea. The sonar performance assessment makes use of acoustic data recorded by a vertical line array at source—receiver ranges from 0.5 to 30 km. Continuous wave pulses at multiple frequencies (300–600 Hz) were transmitted at two source depths, 25 and 60 meters, at each range. At least 60 pings were collected for each source depth to build up the statistics of the acoustic received level and quantify the measurement uncertainty. A comparison of the acoustic transmission loss measured and predicted using an ocean prediction model (ROMS) assimilating the observed oceanographic data is presented, and the performance of the observational network is evaluated. [Work funded by NATO–Allied Command Transformation]
Performance assessment of a short hydrophone array for seabed characterization using natural-made ambient noise
Authors: Nielsen Peter L. , Siderius Martin , Muzi Lanfranco
Published: October 2014

The passive acoustic estimate of seabed properties using natural-made ambient noise received on a glider equipped hydrophone array provides the capability to perform long duration seabed characterization surveys on demand in denied areas. However, short and compact arrays associated with gliders are limited to a few hydrophones and small aperture. Consequently, these arrays exhibit lower resolution of the estimated seabed properties, and the reliability of the environmental estimates may be questionable. The objective of the NATO-STO CMRE sea trial REP14-MED (conducted west of Sardinia, Mediterranean Sea) is to evaluate the performance of a prototype glider array with eight hydrophones in a line and variable hydrophone spacing for seabed characterization using natural-made ambient noise. This prototype array is deployed vertically above the seabed together with a 32-element reference vertical line array. The arrays are moored at different sites with varying sediment properties and stratification. The seabed reflection properties and layering structure at these sites are estimated from ambient noise using both arrays and the results are compared to assess the glider array performance. Synthetic extension of the glider array is performed to enhance resolution of the bottom properties, and the results are compared with these from the longer reference array.
Species classification of individual fish using the support vector machine
Authors: Kinjo Atsushi , Ito Masanori , Matsuo Ikuo , Imaizumi Tomohito , Akamatsu Tomonari
Published: October 2014

The fish species classification using echo-sounder is important for fisheries. In the case of fish school of mixed species, it is necessary to classify individual fish species by isolating echoes from multiple fish. A broadband signal, which offered the advantage of high range resolution, was applied to detect individual fish for this purpose. The positions of fish were estimated from the time difference of arrivals by using the split-beam system. The target strength (TS) spectrum of individual fish echo was computed from the isolated echo and the estimated position. In this paper, the Support Vector Machine was introduced to classify fish species by using these TS spectra. In addition, it is well known that the TS spectra are dependent on not only fish species but also fish size. Therefore, it is necessary to classify both fish species and size by using these features. We tried to classify two species and two sizes of schools. Subject species were chub mackerel (Scomber japonicas) and Japanese jack mackerel (Trachurus japonicus). We calculated the classification rates to limit the training data, frequency bandwidth and tilt angles. It was clarified that the best classification rate was 71.6 %. [This research was supported by JST, CREST.]
Application of time reversal to acoustic noise interferometry in shallow water
Authors: Katsnelson Boris , Godin Oleg , Qin Jixing , Zabotin Nikolai , Zabotina Liudmila , Brown Michael , Williams Neil
Published: October 2014

Two-point cross-correlations function (CCF) of diffuse acoustic noise approximates the Green’s function, which describes deterministic sound propagation between the two measurement points. Similarity between CCFs and Green’s functions motivates application to acoustic noise interferometry of the techniques that were originally developed for remote sensing using broadband, coherent compact sources. Here, time reversal is applied to CCFs of the ambient and shipping noise measured in 100 meter-deep water in the Straits of Florida. Noise was recorded continuously for about six days at three points near the seafloor by pairs of hydrophones separated by 5.0, 9.8, and 14.8 km. In numerical simulations, a strong focusing occurs in the vicinity of one hydrophone when the Green’s function is back-propagated from the other hydrophone, with the position and strength of the focus being sensitive to density, sound speed, and attenuation coefficient in the bottom. Values of these parameters in the experiment are estimated by optimizing focusing of the back-propagated CCFs. The results are consistent with the values of the seafloor parameters evaluated independently by other means.
Shear wave inversion in a shallow coastal environment
Authors: Potty Gopu R. , Giard Jennifer L. , Miller James H. , Baxter Christopher D. P. , Isakson Marcia J. , Goldsberry Benjamin M.
Published: October 2014

Estimation of the shear properties of seafloor sediments in littoral waters is important in modeling the acoustic propagation and predicting the strength of sediments for geotechnical applications. One of the promising approaches to estimate shear speed is by using the dispersion of seismo-acoustic interface (Scholte) waves that travel along the water-sediment boundary. The propagation speed of the Scholte waves is closely related to the shear wave speed over a depth of 1–2 wavelengths into the seabed. A geophone system for the measurement of these interface waves, along with an inversion scheme that inverts the Scholte wave dispersion data for sediment shear speed profiles have been developed. The components of this inversion scheme are a genetic algorithm and a forward model which is based on dynamic stiffness matrix approach. The effects of the assumptions of the forward model on the inversion, particularly the shear wave depth profile, will be explored using a finite element model. The results obtained from a field test conducted in very shallow waters in Davisville, RI, will be presented. These results are compared to historic estimates of shear speed and recently acquired vibracore data. [Work sponsored by ONR, Ocean Acoustics.]
The effects of pH on acoustic transmission loss in an estuary
Authors: Miller James H. , Kloepper Laura , Potty Gopu R. , Spivack Arthur J. , D'Hondt Steven , Turner Cathleen
Published: October 2014

Increasing atmospheric CO2 will cause the ocean to become more acidic with pH values predicted to be more than 0.3 units lower over the next 100 years. These lower pH values have the potential to reduce the absorption component of transmission loss associated with dissolved boron. Transmission loss effects have been well studied for deep water where pH is relatively stable over time-scales of many years. However, estuarine and coastal pH can vary daily or seasonally by about 1 pH unit and cause fluctuations in one-way acoustic transmission loss of 2 dB over a range of 10 km at frequencies of 1 kHz or higher. These absorption changes can affect the sound pressure levels received by animals due to identifiable sources such as impact pile driving. In addition, passive and active sonar performance in these estuarine and coastal waters can be affected by these pH fluctuations. Absorption changes in these shallow water environments offer a potential laboratory to study their effect on ambient noise due to distributed sources such as shipping and wind. We introduce an inversion technique based on perturbation methods to estimate the depth-dependent pH profile from measurements of normal mode attenuation. [Miller and Potty supported by ONR 322OA.]
Receiver operating characteristic analysis for the detectability of malignant breast lesions in acousto-optic transmission ultrasound breast imaging
Authors: Rosenfield Jonathan R. , Sandhu Jaswinder S. , La Rivière Patrick J.
Published: October 2014

Conventional B-mode ultrasound imaging has proven to be a valuable supplement to x-ray mammography for the detection of malignant breast lesions in premenopausal women with high breast density. We have developed a high-resolution transmission ultrasound breast imaging system employing a novel acousto-optic (AO) liquid crystal detector to enable rapid acquisition of full-field breast ultrasound images during routine cancer screening. In this study, a receiver operating characteristic (ROC) analysis was performed to assess the diagnostic utility of our prototype system. Using a comprehensive system model, we simulated the AO transmission ultrasound images expected for a 1-mm malignant lesion contained within a dense breast consisting of 75% normal breast parenchyma and 25% fat tissue. A Gaussian noise model was assumed with SNRs ranging from 0 to 30. For each unique SNR, an ROC curve was constructed and the area under the curve (AUC) was computed to assess the lesion detectability of our system. For SNRs in excess of 10, the analysis revealed AUCs greater than 0.8983, thus demonstrating strong detectability. Our results indicate the potential for using an imaging system of this kind to improve breast cancer screening efforts by reducing the high false negative rate of mammography in premenopausal women.
Using speckle statistics to improve attenuation estimates for cervical assessment
Authors: Kumar Viksit , Bigelow Timothy
Published: October 2014

Quantitative ultrasound parameters like attenuation can be used to observe microchanges in the cervix. To give a better estimate of attenuation we can use speckle properties to classify which attenuation estimates are valid and conform to the theory. For fully developed and only one type of scatterer, Rayleigh distribution models the signal envelope. But in tissues as the number of scatterer type increases and the speckle becomes unresolved Rayleigh model fails. Gamma distribution has been empirically shown to be the best fit among all the distributions. Since more than one scatterer type is present for our work we used a mixture of gamma distributions. EM algorithm was used to find the parameters of the mixture and on basis of that the tissue types were segmented from each other based on the criteria of different scattering properties. Attenuation estimates were then calculated for tissues of the same scattering type only. 67 Women underwent Transvaginal scan and the attenuation estimates were calculated for them after segregation of tissues on scattering basis. Attenuation was seen to decrease as the time of delivery came closer.
Using two-dimensional impedance maps to study weak scattering in isotropic random media
Authors: Luchies Adam , Oelze Michael
Published: October 2014

An impedance map (ZM) is a computational tool for studying weak scattering in soft tissues. Currently, three-dimensional (3D) ZMs are created from a series of adjacent histological slides that have been stained to emphasize acoustic scattering structures. The 3D power spectrum of the 3DZM may be related to quantitative ultrasound parameters such as the backscatter coefficient. However, constructing 3DZMs is expensive, both in terms of computational time and financial cost. Therefore, the objective of this study was to investigate using two-dimensional (2D) ZMs to estimate 3D power spectra. To estimate the 3D power spectrum using 2DZMs, the autocorrelation of 2DZMs extracted from a volume were estimated and averaged. This autocorrelation estimate was substituted into the 3D Fourier transform that assumes radial symmetry to estimate the 3D power spectrum. Simulations were conducted on sparse collections of spheres and ellipsoids to validate the proposed method. Using a single slice that intersected approximately 75 particles, a mean absolute error was achieved of 1.1 dB and 1.5 dB for sphere and ellipsoidal particles, respectively. The results from the simulations suggest that 2DZMs can provide accurate estimates of the power spectrum and are a feasible alternative to the 3DZM approach.
Backscatter coefficient estimation using tapers with gaps
Authors: Luchies Adam , Oelze Michael
Published: October 2014

When using the backscatter coefficient (BSC) to estimate quantitative ultrasound (QUS) parameters such as the effective scatterer diameter (ESD) and the effective acoustic concentration (EAC), it is necessary to assume that the interrogated medium contains diffuse scatterers. Structures that invalidate this assumption can significantly affect the estimated BSC parameters in terms of increased bias and variance and decrease performance when classifying disease. In this work, a method was developed to mitigate the effects of non-diffuse echoes, while preserving as much signal as possible for obtaining diffuse scatterer property estimates. Specially designed tapers with gaps that avoid signal truncation were utilized for this purpose. Experiments from physical phantoms were used to evaluate the effectiveness of the proposed BSC estimation methods. The mean squared error (MSE) for BSC between measured and theoretical had an average value of approximately 1.0 and 0.2 when using a Hanning taper and PR taper, respectively, with six gaps. The BSC error due to amplitude bias was smallest for PR tapers with time-bandwidth product Nω = 1. The BSC error due to shape bias was smallest for PR tapers with Nω = 4. These results suggest using different taper types for estimating ESD versus EAC.
Application of the polydisperse structure function to the characterization of solid tumors in mice
Authors: Han Aiguo , O'Brien William D.
Published: October 2014

A polydisperse structure function model has been developed for modeling ultrasonic scattering from dense scattering media. The polydisperse structure function is incorporated to a fluid-filled sphere scattering model to model the backscattering coefficient (BSC) of solid tumors in mice. Two types of tumors were studied: a mouse sarcoma (Englebreth-Holm-Swarm [EHS]) and a mouse carcinoma (4T1). The two kinds of tumors had significantly different microstructures. The carcinoma had a uniform distribution of carcinoma cells. The sarcoma had cells arranged in groups usually containing less than 20 cells per group, causing an increased scatterer size and size distribution. Excised tumors (13 EHS samples and 15 4T1 samples) were scanned using single-element transducers covering the frequency range 11–105 MHz. The BSC was estimated using a planar reference technique. The model was fit to the experimental BSC using a least-square fit. The mean scatterer radius and the Schulz width factor (which characterizes the width of the scatterer size distribution) were estimated. The results showed significantly higher scatterer size estimates and wider scatterer size distribution estimates for EHS than for 4T1, consistent with the observed difference in microstructure of the two types of tumors. [Work supported by NIH CA111289.]
Numerical simulations of ultrasound-pulmonary capillary interaction
Authors: Patterson Brandon , Miller Douglas L. , Dowling David R. , Johnsen Eric
Published: October 2014

Although lung hemorrhage (LH) remains the only bioeffect of non-contrast, diagnostic ultrasound (DUS) proven to occur in mammals, a fundamental understanding of DUS-induced LH remains lacking. We hypothesize that the fragile capillary beds near the lungs surface may rupture as a result of ultrasound-induced strains and viscous stresses. We perform simulations of DUS waves propagating in tissue (modeled as water) and impinging on a planar lung surface (modeled as air) with hemispherical divots representing individual capillaries (modeled as water). Experimental ultrasound pulse waveforms of frequencies 1.5–7.5 MHz are used for the simulation. A high-order accurate discontinuity-capturing scheme solves the two-dimensional, compressible Navier-Stokes equations to obtain velocities, pressures, stresses, strains, and displacements in the entire domain. The mechanics of the capillaries are studied for a range of US frequencies and amplitudes. Preliminary results indicate a strong dependence of the total strain on the capillary size relative to the wavelength.
Convergence of Green’s function-based shear wave simulations in models of elastic and viscoelastic soft tissue
Authors: Yang Yiqun , Urban Matthew , McGough Robert
Published: October 2014

Green’s functions effectively simulate shear waves produced by an applied acoustic radiation force in elastic and viscoelastic soft tissue. In an effort to determine the optimal parameters for these simulations, the convergence of Green's function-based calculations is evaluated for realistic spatial distributions of the initial radiation force “push.” The input to these calculations is generated by FOCUS, the “Fast Object-oriented C + + Ultrasound Simulator,” which computes the approximate intensity fields generated by a Phillips L7-4 ultrasound transducer array for both focused and unfocused beams. The radiation force in the simulation model, which is proportional to the simulated intensity, is applied for 200 μs, and the resulting displacements are calculated with the Green's function model. Simulation results indicate that, for elastic media, convergence is achieved when the intensity field is sampled at roughly one-tenth of the wavelength of the compressional component that delivers the radiation force “push.” Aliasing and oscillation artifacts are observed in the model for an elastic medium at lower sampling rates. For viscoelastic media, spatial sampling rates as low as two samples per compressional wavelength are sufficient due to the low-pass filtering effects of the viscoelastic medium. [Supported in part by NIH Grants R01EB012079 and R01DK092255.]
Comparison between diffuse infrared and acoustic transmission over the human skull
Authors: Wang Qi , Reganti Namratha , Yoshioka Yutoku , Howell Mark , Clement Gregory T.
Published: October 2014

Skull-induced distortion and attenuation present a challenge to both transcranial imaging and therapy. Whereas therapeutic procedures have been successful in offsetting aberration using from prior CTs, this approach impractical for imaging. In effort to provide a simplified means for aberration correction, we have been investigating the use of diffuse infrared light as an indicator of acoustic properties. Infrared wavelengths were specifically selected for tissue penetration; however this preliminary study was performed through bone alone via a transmission mode to facilitate comparison with acoustic measurements. The inner surface of a half human skull, cut along the sagittal midline, was illuminated using an infrared heat lamp and images of the outer surface were acquired with an IR-sensitive camera. A range of source angles were acquired and averaged to eliminate source bias. Acoustic measurement were likewise obtained over the surface with a source (1 MHz, 12.7 mm-diam) oriented parallel to the skull surface and hydrophone receiver (1 mm PVDF). Preliminary results reveal a positive correlation between sound speed and optical intensity, whereas poor correlation is observed between acoustic amplitude and optical intensity. [Work funded under NIH R01EB014296.]
Leo Beranek's contributions to noise control
Authors: Maling George C. , Lang William W.
Published: October 2014

Leo Beranek has made contributions to noise control for many years, beginning with projects during World War II when he was a Harvard University. Later, at MIT, he taught a course (6.35) which included noise control, and ran MIT summer courses on the subject. His book, Noise Reduction, was published during that time. Additional books followed. Noise control became an important part of the consulting work at Bolt Beranek and Newman. Two projects are of particular interest: The efforts to silence a wind tunnel in Cleveland, Ohio, and the differences in noise emissions and perception as the country entered the jet age. Leo was one of the founders of the Institute of Noise Control Engineering, and served as its charter president. Much of the success of the Institute is due to his early leadership. He has also played an important role in noise policy, beginning in the late 1960s and, in particular, with the passage of the Noise Control Act of 1972. This work continued into the 1990s with the formation of the “Peabody Group,” and cooperation with the National Academy of Engineering in the formation of noise policy.
Technology, business, and civic visionary
Authors: Walden David
Published: October 2014

In high school and college, Leo Beranek was already developing the traits of an entrepreneur. At Bolt Beranek and Newman he built a culture of innovation. He and his co-founders also pursued a policy of looking for financial returns, via diversification and exploitation of intellectual property, beyond their initial acoustics-based professional services business. In particular, in 1956–1957 Leo recruited J.C.R. Licklider to help BBN move into the domain of computers. In time, information sciences and computing became as significant a business for BBN as acoustics. While BBN did innovative work in many areas of computing, perhaps the most visible area was with the technology that became the Internet. In 1969, Leo left day-to-day management of BBN, although he remained associated with the company for more years. Beyond BBN, Leo worked, often in a leadership role, with a variety of institutions to improve civic life and culture around Boston.
Concert hall acoustics: Recent research
Authors: Beranek Leo L.
Published: October 2014

Recent research on concert hall acoustics is reviewed. Discussed are (1) ten top quality halls acoustically; (2) listeners acoustical preferences; (3) how musical dynamics are enhanced by hall shape; (4) effect of seat upholstering on sound strength and hall dimensions; (5) recommended minimum and maximum hall dimensions and audience capacities in shoebox, surround, and fan shaped halls.
Synchronization of organ pipes—Experimental facts and theory
Authors: Abel Markus W. , Fischer Jost L.
Published: October 2014

Synchronization of musical instruments has raised attention due to the important implications on sound production in musical instruments and technological applications. In this contribution, we show new results on the interaction of two coupled organ pipes: we present a new experiment where the pipes were positioned in a plane with varying distance, further we briefly refer to a corresponding description in terms of a reduced model, and eventually show numerical simulations which are in full agreement with the measurements. Experimentally, the 2D setup allows for the observation of a new phenomenon: a synchronization/desynchronization transition at regular distances of the pipes. The developed model basically consists of a self-sustained oscillator with nonlinear, delayed coupling. The nonlinearity reflects the complicated interaction of emitted acoustical waves with the jet exiting at the organ pipe mouth, and the delay term takes care of the wave propagation. Synchronization is a clear evidence for the importance of nonlinearities in music and continues to be a source of astonishing results.
Nonlinear coupling mechanisms in acoustic oscillator systems which can lead to synchronization
Authors: Fischer Jost , Abel Markus
Published: October 2014

We present results on the coupling mechanisms in wind-driven, self-sustained acoustic oscillators. Such systems are found in engineering applications, as gas burners, and—more beautiful—in musical instruments. As a result, we find that coupling and oscillators are nonlinear in character, which can lead to synchronization. We demonstrate our ideas using one of the oldest and most complex musical devices: organ pipes. Building up on the questions of preceding works, the elements of the sound generation are identified using detailed experimental and theoretical studies, as well as numerical simulations. From these results, we derive the nonlinear coupling mechanisms of the mutual interaction of organ pipes. This leads to a nonlinear coupled acoustic oscillator model, which is based on the aeroacoustical and fluid dynamical first principles. The model calculations are compared with the experimental results from preceding works. It appears that the sound generation and the coupling mechanisms are properly described by the developed nonlinear coupled model of self-sustained oscillators. In particular, we can explain the unusual nonlinear shape Arnold tongues of the coupled two-pipe system. Finally, we show the power of modern CFD simulations by a 2D simulation of two mutually interacting organ pipes, i.e., the compressible Navier-Stokes equations are numerically solved.