bluuebunny/crossref_metadata_2025 huggingface dataset:
Algorithmic analysis of sounds using morphometric methods
Authors: Taft Benjamin N.
Published: May 2014

The vast diversity of animal sounds makes it difficult to analyze them in a quantitative, yet general way. Morphological research faces the same scope of variation and has met the challenge of generally applicable quantitative analysis by using landmarks to describe shapes. Spectrograms are a ubiquitous tool in bioacoustics research because they portray sounds visually—as shapes. The SoundPoints application provides a modular set of algorithms that reduce time-varying signals, especially sounds, into sets of landmarks. The landmark stage of analysis provides a layer of abstraction between feature detection and statistics or pattern recognition algorithms. As a result, it is possible to measure the large numbers of sounds that are needed to quantify variation at individual, population, and species levels. To demonstrate measures of stereotypy, I will present a developmental series of Swamp Sparrow (Melospiza georgiana) calls composed of more than 600 000 individual notes. To demonstrate spatial applications of classification, I will use a meta-population analysis of similarity among 22 000 Tree Swallow (Tachycineta bicolor) dawn song syllables.
Large-scale automatic acoustic monitoring of African forest elephants' calls in the terrestrial acoustic recordings
Authors: Shiu Yu , Wrege Peter H. , Keen Sara , Rowland Elizabeth D.
Published: May 2014

African forest elephants live in the rain forests of western and central Africa. The dense habitat prevents them from communicating visually within the family group. Automatic detection of African Forest Elephants' calls intercepts signals in their communication channel and enables fast processing of large scale acoustic data. In this work, first, an automatic detection system targeting at African forest elephants' rumble calls is proposed. De-noising pre-processing, design of acoustic feature vectors, and choice of classifiers are discussed respectively. Second, the detector's performance is evaluated by the cross-validation of a 432-h of acoustic recording from eight locations in Gabon, Africa. It shows that the detector achieve 79.19% true positive rate when the false positive number is the low 5.70 per hour. The F1-score (geometric mean of precision and recall) is around 0.77 when relatively high score threshold (over 0.8) is selected. Finally, a case study demonstrates the results of applying our automatic detection system to a large-scale data set, which amounts to 420 days of acoustic recording over 3 years from the Ivindo National Park, Gabon. Visualization of the call activities reveal the seasonal and daily patterns as well as the temporal variation over the 3 years.
Residency of reef fish during pile driving within a shallow pierside environment
Authors: Iafrate Joseph , Watwood Stephanie , Reyier Eric , Gilchrest Matthew , Crocker Steven
Published: May 2014

The potential effects of pile-driving on fish populations have received significant attention with the prevalence of construction at in-shore areas throughout the world. In this study, the movement and survival of free-ranging reef fish in Port Canaveral, Florida, in response to pile driving for 35 days at an existing wharf was examined through the use of acoustic telemetry. Twenty-seven Sheepshead (Archosargus probatocephalus) and 13 mangrove snapper (Lutjanus griseus) were monitored for a period of approximately 11 months. Underwater acoustic receivers were deployed within Port Canaveral to complement an existing array of compatible receivers spanning a range of over 300 kilometers (km) along the east coast of Florida. Baseline residency and diel patterns of movement were compared for fish in two adjacent locations with and without disturbance before, during, and after the event. There was a significant decline in residency index for mangrove snapper at the construction wharf noted during the pre-during period. Also, 16 of 25 fish tagged at the construction wharf were detected 3-months post tagging, and 11 fish were detected 6-months post tagging. Although there was no apparent impact on patterns of behavior for resident reef fish populations, alterations on behavior of individual fish were noted, including displacement.
Investigating the relationship between foraging odontocetes and ocean acoustic biomass off the Kona coast of the Island of Hawaii
Authors: Copeland Adrienne M. , Au Whitlow , Giorli Giacomo , Polovina Jeffrey
Published: May 2014

To understand the distribution of deep diving odontocetes, it is important to investigate the relationship between foraging whales and their prey. Tagged sperm whales have been documented to dive as deep as 1202 m. Short-finned pilot whales in Hawaii dive deeper during the day down to 600–800 m and shallower dives at night, driven possibly by the migration of organisms at night. Foraging sperm and pilot whales off the Island of Hawaii were located using a hydrophone array detecting echolocation clicks. A 500 m by 500 m active acoustics survey box was set up over two foraging sites: one during the night above foraging sperm whales and one during the day over foraging pilot whales. A four-frequency (38, 70, 120, and 200 kHz) split-beam echosounder collected acoustic data over foraging populations and non-foraging control sites of a similar bottom depth and time. The Nautical Acoustic Scattering Coefficient (NASC) or acoustic biomass (m2nmi−2) profile over the complete water column was statically compared over foraging and non-foraging populations to analyze the relationship between foraging and ocean biomass.
Soundscapes and vocal behavior of humpback whales in Massachusetts Bay
Authors: Merchant Nathan D. , Parks Susan E. , Van Parijs Sofie M. , Wiley David N. , Thompson Michael A. , Friedlaender Ari S.
Published: May 2014

In recent years, technological advances have revolutionized the study of acoustic communication in marine mammals. Exciting new perspectives on vocal behavior, acoustic habitats, and the influence of noise on communication are offered by passive acoustic monitoring (PAM) platforms such as acoustic tags (DTAGs), autonomous PAM recorders, drifting PAM buoys, and subsea gliders. These innovations bring the opportunity to integrate data from fixed and mobile PAM devices to gain deeper insight into the dynamic interactions between marine mammal vocalizations, behavioral context, and the acoustic environment. In this study, we bring together such data sources to study the vocal behavior and acoustic habitat of humpback whales in the context of their spring and summer feeding grounds. Recordings were made in Stellwagen Bank National Marine Sanctuary during 2008–2010, using arrays of autonomous PAM recorders and DTAGs. In addition, AIS ship-tracking data were obtained to study the influence of vessel movements. We present preliminary findings of this work and discuss future strategies for analyzing the spatiotemporal interactions between vocal behavior and acoustical context.
Multimode and other sonar transducer patents of Stanley Ehrlich
Authors: Brown David A.
Published: May 2014

Stanley Ehrlich was an innovative sonar transducer designer and inventor who made many important contributions to the field of acoustic transduction at Raytheon Submarine Signal Division in Portsmouth, Rhode Island. With the advent of searchable digital patent archives at the USPTO and google/patents, it is now relatively easy to review Stan's patents and gain a glimpse at his innovation and creativity. This presentation reviews some these patents including: Sonar Transducer, that describes a multimode transducer producing simultaneously two dipole patterns with mutually perpendicular acoustic axes and an omnidirectional pattern; a Spherical [Multimode] Acoustic Transducer (#3732535 filed 1969) that enables the radial and circumferential vibrating modes of the acoustically excited sphere to be processed to determine bearing. The presentation also draws connections of these and other Ehrlich inventions to more recent ongoing works in multimode transducers.
Automated parameter fitting of two-port network transducer models
Authors: Warren Daniel M.
Published: May 2014

Networks of linear lumped-parameter components, as may be simulated in electronic circuit design software such as SPICE, are a lightweight, fast, and convenient means of predicting the behavior of electroacoustic transducers in practical application. The development of these models can be quite burdensome. The selection and networking of the equivalent electronic components requires specialized domain knowledge of the transduction mechanisms and design of a transducer. Previously, a general network synthesis approach was proposed [Warren, Daniel, “Applications of network synthesis and zero-pole analysis in transducer modeling,” J. Acoust. Soc. Am. 133, 3360–3360 (2013)] but was deemed to be an unreliable and awkward means of developing transducer networks in practice. However, networks that represent transducer behavior are generally well-known for a given transducer type and design. The more difficult task, or, at least, the more often performed and thereby repetitive task, is the selection of component parameter values which correctly predict the transducer's behavior under all electrical drive and acoustical loading conditions which may be encountered in practical application. The approach taken here is to assume that the network itself is already known and seek to develop an automated means of determining the correct parameter values.
Why should a U.S. Navy researcher discuss cicada mating calls for hours with several journalist?
Authors: Hughes Derke
Published: May 2014

The first journalist to comment officially on my cicada research was by American Institute of Physics (AIP), which was quickly followed up by a LA Times reporter. Unfortunately, the LA Times author wrote how the cicada sound system functioned like a Helmholtz resonator. However, when the author actually interviewed me, I contradicted the journalist by saying that I do not believe that theory was correct. Furthermore, I was interviewed by a radio commentator for National Public Radio (NPR) as well who diligently discussed my research and its inspiration for 50 min. My segment aired for 2 min and those few seconds consisted of “crude construction worker harassment and bar talk.” Overall, the opportunity of communicating my research to an international audience was outstanding. The other correspondents that interviewed me for the article were from the ScienceNow and Wall Street Journal. Also, one of my interviewers was a writer for Le Presse so the immediate columnist coverage did span at least two countries. I am proud to have bought awareness to an insect that has been on earth with civilized mankind for millennia; nonetheless, our practical knowledge of the cicada is rather limited.
We don't bite; we want to get it right. Really
Authors: Spotts Peter
Published: May 2014

If a full-time science writer calls you for an interview, count yourself lucky. These days, full-time science writers are a vanishing breed. The reporter about to interview you may be just as nervous about the impending conversation as you are. You know the subject cold. He or she may have had little time to prepare. We'll take a brief look inside one news organization's day (mine) to understand the context on our side of the so-called divide, and share some thoughts on how you can help us explain what you do to your Aunt Elsie or Uncle Sid.
On becoming an expert witness in a high-profile patent-dispute case
Authors: Hamilton Mark F.
Published: May 2014

Several years ago, the author was contacted by the legal team representing a major smartphone manufacturer and asked if he would serve as an expert witness in a patent-dispute case to be tried before an administrative law judge at the International Trade Commission. The author had no significant prior experience as an expert witness, and he therefore had no inkling of what responsibilities lay ahead of him. The author will describe his experiences in this case, beginning with assisting the legal team with understanding the relevant acoustics, then writing expert reports, and finally preparing for deposition and trial.
Progress report—American National Standards Institute Community Noise Standard
Authors: Brooks Bennett M. , Finegold Lawrence S.
Published: May 2014

The American National Standards Institute (ANSI) Accredited Standards Committee S12 (Noise) Working Group (WG) 41 has been developing a draft community noise standard document for over 13 years. The purpose of the document is to provide guidance to government officials, acoustical consultants, and other interested persons on how to develop a community noise ordinance or regulation, which is appropriate for the existing local circumstances. The current version of the document embodies significant revisions, based on the inputs of many stakeholders in the community noise arena, including industry, government, consulting, and the public. The document addresses issues such as public and government priorities and values, and available resources, and also provides the technical basis to manage the local sound environment. The keys to the effectiveness of the document are that it provides a menu of options for the user, discusses the trade-offs involved for decisions that must be made by government officials, and emphasizes that enforcement of a community noise ordinance is crucial to its success. Recent progress made by the Working Group in drafting this standard is reported.
Active control of traffic noise radiation and propagation
Authors: Hu Qi , Tang Shiu-keung
Published: May 2014

Active noise control tends to be challenging, especially for open space scenario. This work intends to control road traffic noise that is treated as an ideal line source with finite length, actively through the introduction of an array of secondary point monopole sources to modify the original sound field, which accordingly creates a quiet zone for the noise sensitive receivers. Three dimensional analytical formulation and numerical simulation are performed to compare the difference before and after the introduction of control sources, through which the optimal position and strength of each control source are studied.
Yeast filtration using large volume flow rate acoustophoretic separation
Authors: McCarthy Brian , Ross-Johnsrud Ben , Lipkens Bart
Published: May 2014

Cell processing occurs in many technologies such as lab-on-a-chip, biopharmaceutical manufacturing, and food and beverage industry. Centrifuges and filters are used in preprocessing and filtration stages. These technologies are not continuous flow filtration methods, a drawback for automation and miniaturization. Continuous cell filtration using ultrasonic standing waves has been successfully used at limited flow rates [Hawkes and Coakley, Enzyme Microbial Technol. 19, 57–62 (1996)]. Advantages of ultrasonic particle filtration are continuous operation with no mechanical moving parts, no risk of membrane fouling, and no consumables. We present a novel design of an acoustophoretic particle separation system operating at large volume flow rates. The technology operates by creating ultrasonic standing waves that produce an acoustic radiation force on particles which exceeds the drag and gravitational forces thereby trapping the particles. Over time aggregation of trapped particles results in gravitational settling of the agglomerated particles. The system comprises a 1 in. × 1 in. flow section and is powered by a 2 MHz PZT-8 transducer and typically operates at flow rates up to 2 L/H. Concentration reductions in excess of 90% are obtained for yeast suspensions of rehydrated S. cerevisiae in RO-DI water with volume concentrations ranging from 0.5 to 3%. [Work supported by NSF PFI:BIC 1237723.]
Optical theorem for beams and application to radiation forces and torques by Bessel beams
Authors: Zhang Likun , Marston Philip L.
Published: May 2014

The optical theorem is known as one of the central theorems in scattering theory; the theorem for plane waves relates the extinction by an object to the scattering amplitude at the forward direction. For a general non-diffracting beam an extended theorem was given recently [Zhang and Marston, J. Acoust. Soc. Am. 131, EL329–EL335 (2012)]. The theorem relates the extinction to the scattering amplitude at the forward direction of plane wave components of the invariant beam. The theorem was used to examine the extinction by a sphere centered on the axis of a non-diffracting Bessel beam [Zhang and Marston, Bio. Opt. Express 4(9), 1610–1617 (2013)]. The results are applied to recover axial radiation force [Zhang and Marston, Phys. Rev. E 84, 035601(R) (2011)] and torque [Zhang and Marston, Phys. Rev. E 84, 065601(R) (2011)] exerted by the Bessel beam on the sphere. This form of optical theorem may be extended to a broader class of incident wave fields. [Zhang was supported by the 2013-14 ASA F. V. Hunt Postdoctoral Research Fellowship. Marston was supported by ONR.]
Experimental investigation of acoustic streaming flows inside a standing wave tube
Authors: Rafat Yasser , Amiri Shahin , Taher Rani , Mongeau Luc
Published: May 2014

Acoustic streaming is identified as one of the several phenomena which affect the efficiency of thermoacoustic system by causing convective heat transfer. In the context of thermoacoustic machines, most of the experimental and numerical studies were performed on Rayleigh acoustic streaming. In the present study, different acoustic streaming flows within a standing wave tube were investigated. Experiments were performed using particle image velocimetry. A rectangular Plexiglas resonator was used as an idealized standing wave thermoacoustic refrigerator. The experimental results were compared with linear acoustic theory to ascertain their validity. Acoustic streaming generated due to interaction of standing wave with thermoacoustic core was also studied. Simplified components were used to model the stack and heat exchangers. It was found that presence of rigid obstacles in the standing wave resonator changed the streaming flow completely. Both the magnitude and shape of the streaming cells changed when compared with the classical Rayleigh streaming cell. The resulting local streaming velocity due to rigid obstacles in the standing wave tube had very high magnitude when compared with streaming in an empty standing wave tube.
The temporal coding of pitch: Insights from human electrophysiology
Authors: Plack Christopher
Published: May 2014

Brian Moore and Roy Patterson have made seminal contributions to our understanding of pitch perception, and in particular the use of temporal pitch information by the auditory brain. The pitch of sounds may be encoded, at least in part, by the tendency of neurons to phase lock to the temporal fine structure and/or envelope of basilar membrane vibration. Direct physiological measures of this mechanism are difficult in humans. However, the gross activity of neurons in the brainstem can be measured using electrophysiological techniques. The frequency-following response (FFR) is an electrophysiological measure of phase locking in the rostral brainstem. The FFR differs between musicians and non-musicians, and across linguistic groups, and is sensitive to short-term pitch discrimination training. These findings suggest that the FFR may reflect neural activity relevant to the encoding of pitch, although other results suggest that it may reflect basic peripheral encoding, rather than the output of a pitch extraction process. Recent results from our laboratory show that combining behavioral and FFR measures can provide insights into the coding of the pitch of pure tones and the coding of musical consonance. The FFR may be a blunt tool, but it provides information that cannot be obtained using other techniques, and this may be particularly useful in investigations of the effects of age and hearing loss on the neural coding of pitch.
Simple models for linear and nonlinear modal vibration of circular cylindrical shells
Authors: Ginsberg Jerry H.
Published: May 2014

Beginning shortly after the Second World War, ONR sponsored projects at Columbia University, New York, that analyzed vibration and shock response of shell structures. This work necessitated ingenuity because it preceded the advent of numerical modeling tools. A central theme was energy methods. This paper will review two works of this type. Baron and Bleich [J. Appl. Mech. 21, 178–184 (1954)] used the mechanical energies of the Flugge-Byrne-Lur’ye shell theory and a fundamental property of the modal energies to obtain accurate formulas for the three vibration branches and associated modal displacements of a simply supported cylindrical shell. This author [Ginsberg, J. Appl. Mech. 40, 471–477 (1973)] used these modes to analyze finite amplitude effects at resonances. Examination of the order of magnitude of terms in the mechanical energies led to identification of nonlinear mode coupling. The resulting differential equations for the modal coordinates were solved by a singular perturbation technique. The outcome was a set of algebraic equations for the nonlinear frequency response, and disclosure of the conditions under which an azimuthally symmetric response destablizes in favor of an antisymmetric response as a consequence of nonlinear coupling.
Vowel systems of quantity languages compared: Arabic dialects and other languages
Authors: Rosenhouse Judith K. , Amir Noam , Amir Ofer
Published: May 2014

The acoustic phonetic features of colloquial Arabic vowel systems are still not entirely researched. This paper studies phonetic structure of several Arabic dialects and other languages. A basic issue is the fact that Arabic is a quantity language; but from the published literature we see that vowel systems of Arabic dialects differ in many acoustic details. We researched two colloquial Arabic dialects which are spoken in Israel, and hitherto not acoustically studied. These dialects constitute the axis around which we conducted the literature-based comparison with vowel systems of a few other Arabic dialects and other languages which share similar quantity features (i.e., long and short vowels). The study reveals similarities and differences in pitch (F0), the first three formants and duration. These differences appear between the two Arabic dialects spoken in Israel, between them and other Arabic dialects, as well as between non-Arabic languages (English, German, Swedish, and Hungarian). The findings of our study are discussed in relation with the questions of (1) vowel spaces of short and long vowels and (2) speaker's sex-dependent differences.
The articulation of lexical palatalization in Scottish Gaelic
Authors: Sung Jae-Hyun , Archangeli Diana , Clayton Ian , Brenner Daniel , Johnston Samuel , Hammond Michael , Carnie Andrew
Published: May 2014

Scottish Gaelic (Gàidhlig, henceforth SG) exhibits a rich system of consonant mutation, which is mostly governed by its morphology (Ladefoged et al. 1998; Gillies 2002; Stewart 2004). For instance, bàta “boat” changes to [v] when the word undergoes morphological inflection—e.g., a bhàta “his boat”, in which the sound spelled bh is pronounced as [v]. Using ultrasound imaging, the present study investigates palatalization in SG, which is considered as one of lexicalized consonant mutation types. Experimental data was collected in Sabhal Mòr Ostaig, a college on the Isle of Skye. Preliminary results show a clear sign of palatalization across different consonant types in palatalization environments (i.e., when morphologically conditioned), represented by higher tongue contours in the front region of tongue. While the articulatory distinction between plain and palatalized consonants is significant, different syllabic positions (i.e., word-initial vs. -final palatalization) often yield individualized patterns.
A cross-linguistic study of lexical stress shifts in level 1 [ + cyclic] derivations
Authors: Keyworth Paul R.
Published: May 2014

Laboratory phonology has been widely employed to understand the interactional relationship between the acoustic cues of English Lexical Stress (ELS)—duration, fundamental frequency, and intensity. However, research on ELS production in polysyllabic words is limited, and cross-linguistic research in this domain even more so. Hence, the impacts of second language (L2) experience and first language (L1) background on ELS acquisition have not been fully explored. This study of 100 adult Mandarin (Chinese), Arabic (Saudi Arabian), and English (Midwest American) speakers examines their ELS productions in tokens containing seven different stress-moving suffixes; i.e., Level 1 [ + cyclic] derivations according to lexical phonology. Speech samples were systematically analyzed using Praat and compared using statistical sampling. Native-speaker productions provided norm values for cross-reference to yield insights into the proposed Salience Hierarchy of the Acoustic Correlates of Stress (SHACS). The author recently reported the main findings which support the idea that SHACS exists in L1 sound schemes, and that native-like command of these systems can be acquired by L2 learners through increased L2 input. Other results are expected to reveal the role of tonic accent shift, the idiosyncrasies of individual suffixes, conflicts with standard dictionary pronunciations, and the effects of frequency perception scales on SHACS.
Effects of observing or producing hand gestures on non-native speakers’ auditory learning of Japanese short and long vowels
Authors: Hirata Yukari , Kelly Spencer D. , Huang Jessica , Manansala Michael
Published: May 2014

This study examined whether auditory training coupled with hand gesture can improve non-native speakers’ auditory learning of phonemic vowel length contrasts in Japanese. Hirata and Kelly (2010) found that observing hand gesture that moved along with the rhythm of spoken short and long vowels in Japanese did not uniquely contribute to non-native speakers’ auditory learning. The present study compared effects of four types of training to examine whether there is a more effective method: (1) producing syllabic-rhythm gesture, (2) observing syllabic-rhythm gesture, (3) producing moraic-rhythm gesture, and (4) observing moraic-rhythm gesture. Each of native English speakers (N = 88) participated in one of the four types of training in four sessions, and took a pretest and a posttest that measured their ability to auditorily identify the vowel length of novel words without hand gesture. Tested disyllable pairs had the contrast in the first and the second syllables, spoken in sentences at slow and fast rates. Results showed that all four groups improved significantly (9%), but the amount of improvement did not differ. However, ‘observing syllabic-rhythm gesture’ was the only condition in which auditory learning was balanced between the first and the second syllable contexts and between the slow and fast rates.
The effect of language experience on the ability of non-native listeners to identify Japanese phonemic length contrasts
Authors: Hisagi Miwako , Tajima Keiichi , Kato Hiroaki
Published: May 2014

This study investigated how language experience affects second-language (L2) listeners’ ability to perceive phonemic length contrasts in the face of stimulus variability. Native English-speaking learners of Japanese (N = 42) participated in an identification task in which the stimuli were Japanese words contrasting in vowel or consonant length, produced in isolation or embedded in a carrier sentence at slow, normal, or fast speaking rates, presented in a random order. Participants also received an Oral Proficiency Interview (OPI), developed by the American Council on the Teaching of Foreign Languages (ACTFL), to assess their Japanese proficiency on a 10-level scale. Results showed that identification accuracy as measured by d’ was weakly correlated with OPI level (r = 0.298), and moderately correlated with number of semesters enrolled in Japanese language courses (r = 0.401). Speaking rate significantly affected performance, but its effect differed by context. For word-in-isolation context, d' was highest at the normal rate, while for word-in-sentence context, d' was highest at the slow rate. However, the effect of speaking rate was not reduced as a function of OPI level or number of semesters in Japanese courses. Thus, language experience may not always strongly predict L2 speech perception. [Work supported by JSPS-KAKENHI, MIT-RLE and -Linguistics & Philosophy.]
Multiple sources of information contribute to novel category formation
Authors: Cibelli Emily
Published: May 2014

The acquisition of novel phonemes in a new language often presents a challenge for learners, particularly when target categories overlap with or assimilate to native categories. In the current study, English speakers who have no experience with Hindi are asked to learn the Hindi dental-retroflex place contrast and the four-way stop voicing contrast. The multi-day study includes an AX discrimination task and a repetition task with (V)CV syllables. In experiment 1, a training procedure was designed to manipulate multiple sources of information available to the listener. Training sessions include performance feedback and adaptive fading (a progression in exposure from clear tokens to more peripheral exemplars). Critically, the study also includes explicit articulatory training of the target sounds, to test the hypothesis that information about the existence of a new articulatory target can support the development of a perceptual category. Experiment 2, a control study, tests whether simple exposure to stimuli without feedback or training has any effect on performance. Without training, discrimination remained at baseline levels, suggesting that short-term exposure alone is insufficient for category formation. The place contrast presented the biggest challenge for listeners, with some improvement in performance if a voicing cue co-occurred with the place contrast.
Native English speakers' perception of Arabic emphatic contrasts
Authors: Durham Kristie , Zaba Aleksandra , Hayes-Harb Rachel
Published: May 2014

In Arabic, emphasis (secondary velar/pharyngeal constriction) distinguishes some consonants. Native Jordanian Arabic speakers have been shown to rely more heavily on the rime than the onset of CVC syllables when identifying plain versus emphatic onsets (Jongman et al. 2011). We investigated whether native English speakers similarly rely on the rime when discriminating Arabic plain-emphatic pairs. We also investigated the influence of vowel quality on discrimination performance. Native English speakers (no Arabic experience) performed an AXB task involving cross-spliced CVCs with plain/emphatic onsets/rimes. Our subjects also relied more heavily on the rime than on the onset; this effect was most robust when the V was /æ/, followed by /u/ and /i/. A cross-language vowel identification task revealed that subjects identified Arabic /æ/ in emphatic contexts as systematically different English vowels than in plain contexts, with only 10% overlap in vowels identified. The overlap for /i/ and /u/ was much higher, at 84% and 91%, respectively. We thus found that native English listeners, like native Arabic listeners, rely on the rime to make onset emphasis judgments, this effect is moderated by vowel, and the influence of the preceding vowel may be related to the mapping between vowel allophones and English vowel categories.
Reproduction of higher order virtual sources using loudspeaker arrays
Authors: Choi Jung-Woo , Kim Yang-Hann
Published: May 2014

Reproduction of a monopole virtual source has been extensively studied for providing the locatedness or directional information to the listener. The monopole virtual source is often assumed to be omni-directional, and the driving signals of multiple loudspeakers are determined such that the uniform radiation pattern can be reproduced in space and time. The virtual source of which radiation pattern consists of higher order radiation pattern, however, can also be reproduced for the control of perceived stage width or focusing of acoustic energy. In this work, we introduce various applications involving the higher order radiation pattern. The magnitude or phase distribution rapidly changing in space and time is reproduced by an array of loudspeakers, and the limitation of the conventional reproduction technique based on the stationary phase approximation, e.g., wave field synthesis, is demonstrated. A single layer formula to eliminate the artifact of the conventional technique is addressed.
A constrained adaptive beamforming algorithm for spherical microphone arrays
Authors: Elko Gary W. , Meyer Jens M.
Published: May 2014

In this presentation, we will present a novel constrained adaptive beamformer algorithm that utilizes an inherent property of spherical harmonic eigenbeams which form the bases signals for spherical microphone array beamforming. Two simple constraints are placed on the weights to preclude the adaptive beamformer from nulling signals arriving from a desired “look” direction. The adaptive algorithm has been simulated for some simple acoustic fields as well as a diffuse field. We have implemented the algorithm in realtime on mh acoustics em32 Eigenmike¯ spherical microphone array and we will present some measurement results.
Multichannel myopic deconvolution using ambient noise sources
Authors: Tian Ning , Romberg Justin , Sabra Karim
Published: May 2014

The ocean ambient noise has been increasingly utilized for ocean passive sensing and monitoring applications. By recording the received signals from the same individual noise source (for example, the shipping noise) at multiple hydrophones simultaneously, we develop a framework, called multichannel myopic deconvolution, which can allow us jointly estimate the source and the channel responses without any assumption about the source, but using some priori knowledge of the channel. Our work on this classical signal processing problem has two novel aspects. First, we recast the corresponding bilinear system of equations as a linear system with a rank constraint. This allows us to apply recently developed algorithms and analytical tools from the field of low-rank recovery to the blind channel estimation problem, yielding insight into the conditions under which accurate channel estimation is possible. Second, we incorporate (continuous-time) parametric uncertainty about the Green's functions as subspace constraints in the low-rank recovery problem. These subspaces are generated in a systematic way using the singular value decomposition, and their dimension can be directly related to the amount of priori knowledge we have about the channel. We will present simulations in shallow water environments of the proposed approach from relatively short observation times.
The interference structure of very low frequency vector acoustic field and its positioning application
Authors: Dajun Sun , Junjie Shi , Yunfei Lv , Hualin Lan , Jidan Mei
Published: May 2014

Vector hydrophone has natural dipole beam-pattern, and can also simultaneously and colocatedly measure the scalar and vector information of ocean acoustic field, which makes it convenient to determine the direction of arrival (DOA) and represent the stable interference structure of vector acoustic field. Utilizing the DOA and interference structure information together acquired by single vector hydrophone, it is able to position the target of interest. Firstly, bearing-time course for passing-by target is obtained by using the line or continuous spectrum imbedded in the received signal of vector hydrophone. Then, CPA ratio between the CPA range and speed of target as well as CPA instant are estimated on the basis on LMS criteria. Finally, the speed of target can be determined through the theoretically predicted interference range and the real interference time interval to fulfill target positioning including DOA and range. The idea was effectively validated during the experiment that took place in October of 2010 in South China Sea nearly 100m depth. Moreover, the idea presented here can be easily extended for further application such as combining the waveguide invariant. [Work supported by the National 863 Project (No. 2011AA090502) and National Defense Foundation Project (B2420132004).]
The influence of directional sea-surface waves on the acoustic intensity vector field
Authors: Dall'Osto David R. , Dahl Peter H.
Published: May 2014

The effects of a rough sea surface on shallow water acoustic propagation are examined using experimental data collected from the Target and Reverberation Experiment (TREX) which took place off of the coast of Panama City, Florida in May 2013. During the experiment, the sea surface directional-wave spectrum was measured by a pair directional buoys moored at the experimental site. Acoustic measurements were collected using a bottom deployed recording tower (depth 20 m), that coherently recorded data from an accelerometer-based vector sensor, and a horizontal and vertical line array. Measurements using an active source, lowered from the stern of a research vessel, were made along propagation paths perpendicular and parallel to the surface wind-waves at source receiver ranges corresponding to approximately 10, 20, and 40 water depths. Results show that the directional properties of the rough sea-surface influence both the azimuthal and vertical distribution of the forward scattered intensity. A frequency dependence in vertical angular spreading is identified for the frequency range 1 to 3 kHz. A partial explanation for this effect originates from differences in the directional wave spectral level corresponding to forward scattering Bragg wavenumbers that are computed from the angles of the trapped modes.
Joint estimation of frequency and azimuth using acoustic vector sensor signals based on sparse decomposition theory
Authors: Fu Jinshan
Published: May 2014

Acoustic vector sensor can obtain more information of sound field compared with scalar hydrophone. The sparse decomposition theory was put forward in the 90s of last century, and it provides a simple, flexible, and self-adaptive representation method of signal. Through sparse decomposition theory, it can essentially reduce the cost of signal processing and improve the compression efficiency. Space-time array manifold is constructed through signal analysis of single acoustic vector sensor (AVS). Based on sparse decomposition theory, the frequency and azimuth estimation algorithm is proposed, the frequencies and azimuths of multi-targets are estimated simultaneously by the joint estimation algorithm. Results using simulated data received from single acoustic vector sensor are illustrated. The accurate estimation of multi-targets’ frequencies, azimuths, and signal amplitudes can be obtained using the estimation algorithm we deduced. Then, the influence of targets number, signal-to-noise (SNR), snapshots number on algorithm performance is analyzed.
Some effects of reflections and delayed sound arrivals on the perception of speech and corresponding measurements of the speech transmission index
Authors: Mapp Peter
Published: May 2014

Although the effects of reflections and later arriving sound repetitions (echoes) have been well researched and published over the past 60 years—ranging from Haas, Wallach, and more recently to Bradley & Sato and Toole, their effect on Speech Transmission Index measurements and assessments has only be cursorily studied. Over the past 20 years, the speech Transmission Index (STI) has become the most widely employed measure of potential speech intelligibility for both natural speech and more importantly of Public Address and emergency sound systems and Voice Alarms. There is a common perception that STI can fully account for echoes and late, discrete sound arrivals and reflections. The paper shows this not to be the case but that sound systems achieving high STI ratings can exhibit poor and unacceptable speech intelligibility due to the presence of late sound arrivals and echoes. The finding is based on the results of a series of listening tests and extensive sound system modeling, simulations and measurements. The results of the word score experiments were found to be highly dependent upon the nature of the test material and presentation.
Effects of room-acoustic exposure on localization and speech perception in cocktail-party listening situations
Authors: Sudirga Renita , Cheesman Margaret F. , Macpherson Ewan A.
Published: May 2014

Given previous findings suggesting perceptual mechanisms counteracting the effects of reverberation in a number of listening tasks, we asked whether listening experience in a particular room can enhance localization and speech perception abilities in cocktail-party situations. Utilizing the CRM stimuli we measured listeners' abilities in: (1) identifying the location of a speech target given a (-22.5o, 0o, + 22.5o) talker configuration, (2) identifying the target color/number under co-located (0o, 0o, 0o) and spatially-separated (Ő22.5o, 0o, + 22.5o) configurations. Stimuli were presented in three types of artificial reverberation. All reverberation types had the same relative times-of-arrival and levels of the reflections (T60 = 400 ms, C50 = 14 dB; wideband) and varied only in the lateral spread of the reflections. Reverberated stimuli were presented via a circular loudspeaker array situated in an anechoic chamber. Listening exposure was varied by mixing or fixing the reverberation type within a block of trials. For the location identification task, exposure benefit decreased with increasing Target-to-Masker Ratio (TMR). No exposure effect was observed in the speech perception task at Ő4 to 10 dB TMRs, except in the separated, narrowest reverberation condition. Results will be discussed in relation to the different nature of the tasks and findings from other studies.
Establishing baselines for cetaceans using passive acoustic monitoring off west Africa
Authors: Rekdahl Melinda , Cerchio Salvatore , Rosenbaum Howard
Published: May 2014

Knowledge of cetacean presence in west African waters is sparse due to the remote and logistically challenging nature of working in these waters. Exploration and Production (E&P) activities are increasing in this region; therefore, collecting baseline information on species distribution is important. Previous research is limited although a number of species listed as vulnerable or data deficient by the IUCN red list have been documented. In 2012/2013, we deployed an array of eight Marine Autonomous Recording Units (MARUs) in a series of three deployments, off Northern Angola, targeting Mysticetes (2 kHz SR, continuous) during winter/spring and Odontocetes (32 kHz SR, 20% duty cycled) during summer/autumn. Preliminary results are presented on the temporal and spatial distribution of species identified from automated and manual detection methods. Humpback whales were frequently detected from August through December, with peaks during September/October. During the deployment period, sperm whales and Balaenopterid and Odontocete calls were also detected and possible species will be discussed. Species detections will be used to identify temporal hotspots for cetacean presence and any potential overlap with E&P activities. We recommend that future research efforts include visual and acoustic vessel surveys to increase the utility of passive acoustics for monitoring these populations.
Classifying humpback whale individuals from their nocturnal feeding-related calls
Authors: Huang Wei , Wu Fan , Makris Nicholas C. , Makris Purnima R.
Published: May 2014

A large number of humpback whale vocalizations, comprising of both songs and non-song calls, were passively recorded on a high-resolution towed horizontal receiver array during a field experiment in the Gulf of Maine near Georges Bank in the immediate vicinity of the Atlantic herring spawning ground from September to October 2006. The non-song calls were highly nocturnal and dominated by trains of “meows,” which are downsweep chirps lasting roughly 1.4 s in the 300 to 600 Hz frequency range, related to night-time foraging activity. Statistical temporal-spectral analysis of the downsweep chirps from a localized whale group indicate that these “meows”can be classified into six or seven distinct types that occur repeatedly over the nighttime observation interval. These meows may be characteristic of different humpback individuals, similar to human vocalizations. Since the “meows” are feeding-related calls for night-time communication or prey echolocation, they may originate from both adults and juveniles of any gender; whereas songs are uttered primarily by adult males. The meows may then provide an approach for passive detection, localization and classification of humpback whale individuals regardless of sex and maturity, and be especially useful for night-time and/or long range monitoring and enumeration of this species.
Quantitative acoustic microscopy at 250 MHz for unstained ex vivo assessment of retinal layers
Authors: Rohrbach Daniel , Lloyd Harriet O. , Silverman Ronald H. , Mamou Jonathan
Published: May 2014

Few quantitative acoustic microscopy (QAM) investigations have been conducted on the vertebrate retina. However, quantitative assessment of acoustically-related material properties would provide valuable information for investigating several diseases. We imaged 12-μm sections of deparaffinized eyes of rdh4 knockout mice (N = 3) using a custom-built acoustic microscope with an F-1.16, 250-MHz transducer (Fraunhofer IBMT) with a 160-MHz bandwidth and 7-μm lateral beamwidth. 2D QAM maps of ultrasound attenuation (UA) and speed of sound (SOS) were generated from reflected signals. Scanned samples then were stained using hematoxylin and eosin and imaged by light microscopy for comparison with QAM maps. Spatial resolution and contrast of QAM maps of SOS and UA were sufficient to resolve anatomic layers within the 214 μm thick retina; anatomic features in QAM maps corresponded to those seen by light microscopy. UA was significantly higher in the outer plexiform layer (420±70 dB/mm) compared to the inner nuclear layer (343±22 dB/mm). SOS values ranged between 1696±56 m/s for the inner nuclear layer and 1583±42 m/s for the inner plexiform layer. To the authors’ knowledge, this study is the first to assess the UA, and SOS of retina layers of vertebrate animals at high frequencies. [NIH Grant R21EB016117 and Core Grant P30EY019007.]
An experimental investigation on the near-field turbulence for an airfoil with trailing-edge serrations at different angles of attack
Authors: Xu Kunbo , Qiao Weiyang
Published: May 2014

The ability to fly silently of most owl species has long been a source of inspiration for finding solutions for quieter aircraft and turbo machinery. This study concerns the mechanisms of the turbulent broadband noise reduction for an airfoil with the trailing edge serrations while the angles of attack varies from + 5° to Ő5°. The turbulence spatio-temporal information are measured with 3D hot-wire. The experiment is carried out in the Northwestern Polytechnical University low speed open jet wind tunnel on the SD2030 airfoil. λ/h = 0.2. It is showed the spreading rate of the wake and the decay rate of the wake centerline velocity deficit increased with serrated edge compared to the straight edge, and the three components of velocity changed differently with serrated trailing edge while the angle of attack was changed. It is also found that the turbulence peak occurs further from the airfoil surface in the presence of the serrations, and the serrations widened the mix area which allowed the flow mixed together ahead of the schedule.