bluuebunny/crossref_metadata_2025 huggingface dataset:
A constrained optimization technique for the design of a uniformly excited N×N ultrasonic transducer micro-array
Authors: Whitney James , Etienne-Cummings Ralph
Published: October 2013

A method for obtaining the optimal and specific sensor parameters for an ultrasonic transducer micro-array is presented. The ultrasonic transducer array sensor parameters, such as frequency of operation, element size, interelement spacing, number of elements, and transducer geometry, are adjusted using a quadratic programming method to obtain maximum directivity while being constrained by MEMS design rules, a total array size of 4 mm2, and the required resolution for microsurgery. The technique is used to determine whether a uniformly spaced N×N transducer array is capable of resolving structures as small as 2 μm. The parameters extracted from the proposed technique will be used in the development of tool-mounted sensors for imaging and robotic guidance for retinal microsurgery.
Three-dimensional ultrasound image registration and shear elastic modulus reconstruction
Authors: Richards Michael S. , Gokhale Nachiket H. , Barbone Paul E. , Oberai Assad A.
Published: October 2013

It is widely recognized that tissue pathologies often change biomechanical properties. For instance, neoplastic tissue is typically highly vascularized, contains abnormal concentrations of extracellular proteins (i.e., collagen, proteoglycans) and has a high interstitial fluid pressure compared to most normal tissues. The aim of this work is to develop and evaluate an ultrasound technique to quantitatively measure and image the mechanical properties of soft tissues in three dimensions. The intended application of our work is in the detection and diagnosis of breast cancer and other soft tissue pathologies. The specific goal of this project is the accurate measurement of the elastic shear modulus distribution of a tissue-mimicking ultrasound phantom, using a 3-D ultrasound imaging system. This requires the design and characterization of algorithms to provide three-dimensional motion estimates from ultrasound images and to solve the three-dimensional inverse problem to recover shear elastic modulus. Modulus images, reconstructed using our algorithms, are presented and compared to values determined by independent mechanical testing. The effect of the boundary conditions and regularization methods on the reconstructed modulus images and the uniqueness of the solution is also discussed.
Motion detection for vibro-acoustography
Authors: Urban Matthew , Greenleaf James
Published: October 2013

Vibro-acoustography is a method that uses ultrasound radiation force to investigate the mechanical response of an object [Fatemi and Greenleaf, ‘‘Ultrasound-stimulated vibro-acoustic spectrography,’’ Science, 280, 82–85 (1998)]. The dynamic radiation force causes the object to vibrate within the focal region of the transducer, which creates a sound field called acoustic emission measured by a hydrophone. To gain a better understanding of the objects investigated with vibro-acoustography, a method is proposed that measures the displacement of the local vibration. A pulse-echo ultrasound method is implemented with the same transducer used to create the radiation force to measure the displacement of the object. A Kalman filter approach is used to process the pulse-echo data to obtain estimates of the local displacement [Zheng et al., ‘‘Kalman filter motion detection for vibroacoustography using pulse-echo ultrasond,’’ 2003 IEEE Ultrasonics Symposium, pp. 1812–1815 (2003)]. Results using this ultrasound method to measure vibration of a metal beam compare well with laser vibrometer results. This method can reliably measure displacements with amplitudes of 120–2000 nm with error less than 9%. A pulse-echo method is described that provides displacement detection with simultaneous radiation force generation for vibro-acoustography applications using a single transducer. [Work supported by Grants EB002640 and EB002167 from NIH.]
Transcranial ultrasound tracking of brain shift
Authors: Ross Anthony B. , Clement Greg T.
Published: October 2013

Transcranial ultrasound provides a portable, inexpensive, rapid, and nonionizing technique to measure brain shift and structural changes. This technique may have important implications in neurosurgery, emergency room diagnosis, and long-term or frequent patient monitoring. The ability of transcranial ultrasound to measure motion inside the skull was investigated in ex vivo human skulls. The skulls were submerged in degassed water and a 2-D velmax positioning system was used to position a small needle within the skull. An array of low-frequency transducers (0.5–2 MHz) was positioned in a frame around the skull. Ultrasound pulses were sent in longitudinal and shear wave modes through the skull. The digitized receive signals of all transducers were then analyzed with Matlab. Using geometric and time-of-flight analysis the magnitude and direction of the needle shifts were determined. The transcranial ultrasound tracking system was able to accurately (within 0.2 mm) detect the needle motion in the skull. Overall, transcranial ultrasound using both shear and longitudinal waves was shown to be an effective method to track motion in the skull and may be a useful real time method to correct for misregistration of presurgical images. [Work supported by NIH Grants R21EB004353 and U41RR019703.]
Singular spectrum analysis applied to ultrasonic imaging of brachytherapy seeds
Authors: Mamou Jonathan , Feleppa Ernest
Published: October 2013

Singular spectrum analysis (SSA) shows promise for reliably imaging radioactive seeds implanted in the prostate gland. Brachytherapy using small titanium-shelled radioactive seeds is proving to be a well-accepted means of treating prostate cancer. Unfortunately, implantation using needles inserted transperineally causes gland movement, and the resulting distortion may cause seed misplacement and dosimetry errors. If actual seed locations can be determined during the brachytherapy procedure, then dosimetry errors can be corrected immediately in the operating room. SSA utilizes pairs of eigenvalues derived from the autocorrelation matrix of envelope-detected radiofrequency echo signals to identify seed-specific signal repetitions. The power spectrum associated with a repetition signal is computed to derive a P-value indicative of the likelihood of the presence of a seed at the location of that repetitive signal. Simulations to assess performance as a function of different levels of white and speckle noise and the presence of signals at repetition periods not associated with seeds. Experiments in an ideal scattering environment were performed, using seeds implanted in beef. Results show an encouraging potential of SSA for seed detection and imaging, and illustrate the basic trade-off considerations for optimization of SSA for clinical applications. [Work supported by NIH Grant R01 CA098465.]
Quantitative evaluation of architectural acoustics computer models
Authors: Beers Christopher J. , Celmer Robert D.
Published: October 2013

Computer modeling has enhanced many professional fields, including that of architectural acoustics. The accuracies of these models should be known if they are to be used in the design process. While some calculations in architectural acoustics software have been well established (such as the Sabine and Eyring reverberation time), the development of other higher-order algorithms is more recent. The purpose of this investigation is to examine possible methods for evaluating accuracy in architectural acoustics computer models. Recordings were made in an existing space, and analogous audio files were generated through one such software package. The recorded and calculated audio files were then compared via multiple means. The effectiveness and appropriateness of each metric was analyzed. Conclusions were drawn regarding the metrics and subsequent research implications were explored. [Work supported by ASA Robert W. Young Award for Undergraduate Student Research in Acoustics.]
Status of acoustics in Russia
Authors: Dubrovskiy Nikolay A.
Published: October 2013

Acoustics is developed mainly in Moscow, Saint Petersburg, Nizhny Novgorod, and Vladivostok. Studies are performed in different directions including both fundamental studies and applied research connected with the needs of Russian industry and the developing Russian market. Coordination of works on acoustics and dissemination of knowledge are implemented mainly by the Russian Acoustic Society (RAO), East European Association of the acousticians (EEAA), and the Council for Acoustics of the Russian Academy of Sciences. RAO carries out 1 or 2 scientific sessions yearly. This year RAO conducted two sessions. The basic periodical of Russian acousticians is Acoustical Physics. Science (and acoustics, in particular) in Russia is slowly reviving after a crisis happened after the collapse of the Soviet Union. This crisis manifests itself in significant reduction in funding; loss of prestige in being a scientist; young people leaving science and the aging of personnel; capable acousticians leaving the country; lack of demand for scientific innovations by Russian industry; lack of experience to work within the market economy; and absence of adequate tools for financing R&D. Wide international collaboration has become a positive factor for Russian acoustics. ASA provided valuable financial support for young Russian acousticians in recent years. [This lecture is supported by the ASA.]
Whole-body finite-difference formulation of the violin
Authors: Bader Rolf
Published: October 2013

The whole body of a violin was modeled with the finite-difference method in terms of a transient calculation. The model, like a previous guitar body model, takes bending or transversal and longitudinal or in-plane motion of the wooden body into consideration and couples these two kinds of vibrations. Here, the curvature of the violin body also enhances this coupling according to the amount of curvature. The string/bow mechanism was modeled in terms of sticking/slipping, depending on the displacement difference of the bowing point to a point next to this bowing point. The different parts of the violin show different behavior within the steady state of one bowing cycle. Most noticeable, the ribs showed a chaotic motion, causing it to be quite small and greatly influenced by the surrounding parts. As this is practically the only part with noisy components, we can say the violin bowing noise comes from the ribs. Additionally, initial transients were modeled by changing the bowing pressure and velocity over the intial transient phase for a soft and a hard attack, resulting in reasonable descriptions of the violin playing attack.
From articulation index to speech privacy: A review
Authors: Beranek Leo L.
Published: October 2013

Communication by voice over wired and radio systems is ever more important. Voice recognition by machine is commonplace today, whether it involves a person telephoning into an organization or the government spying on international communications. In these examples, context is not yet highly developed, so that the advantage a person has in understanding a sentence even if all words are not perceived does not ordinarily exist. Thus, correct understanding of isolated words is crucial. Two papers pioneered in establishing a metric for determining the degree of understanding of words in the presence of noise [French and Steinberg, ‘‘Factors governing the intelligibility of speech sounds,’’ J. Acoust. Soc. Am. 19, 90–119 (1947); Beranek, Proc. I.R.E., 35, 880–890 (1947)]. This paper will review the basic principles taught in those papers. Very low values of AI (i.e., little or no intelligibility) proved critical in studies on speech privacy in buildings by BBN scientists some 50 years ago. Those early studies also confirmed the relative importance of masking sounds in offices and other spaces, sometimes referred to as acoustic perfume, in achieving desired degrees of speech privacy.
Speech privacy in buildings: A review
Authors: Cavanaugh William , Hirtle Parker
Published: October 2013

Studies on speech privacy problems in buildings at Bolt Beranek and Newman begun in the mid 1950s showed convincingly that a person’s sense of acoustical privacy was directly related to the intelligibility of the intruding speech over the continuous ambient sound present [Cavanaugh et. al., J. Acoust. Soc. Am. 34, 475–492 (1962)]. Both in laboratory and in real-world settings people feel they have confidential privacy when the articulation index (AI) of the intruding speech is 0.05 or less. Higher values of AI are acceptable for less demanding tasks, i.e., normal privacy. The method quantifies each of the significant variables involved and compares a summary of these metrics with response data for prior case histories both to predict, and, in the case of existing situations, to evaluate speech privacy conditions. R. W. Young reviewed the analysis method and showed that sufficient accuracy was preserved if simple, commonly used A-scale sound levels were used in place of more cumbersome frequency-based metrics [R. W. Young, J. Acoust. Soc. Am. 38, 524–533 (1965)]. Later in the 1960s the method was successfully applied to open plan offices which were becoming more prevalent [Hirtle et. al., J. Acoust. Soc. Am. 46. 91A (1969)]. The lessons learned in applying the speech privacy calculation over the years are discussed.
Postoccupancy assessment of speech privacy in offices
Authors: Salter Charles , Waldeck Randy , Powell Kevin
Published: October 2013

The General Services Administration (GSA) Workplace 20.20 initiative includes acoustical design analysis for offices. Internet questionnaires about acoustics and occupant satisfaction have been filled out by hundreds of GSA office workers. These results have been correlated with acoustical testing that our firm, Charles M. Salter Associates, Inc., has conducted during the last 4 years around the country. Survey responses, which are correlated with the results of our acoustical testing, will be presented.
Open-plan privacy revisited
Authors: Pirn Rein
Published: October 2013

Driven by a desire for economy, the open office has been with us since before World War II. However, it was not until the 1960s that largely through the work of a Quickborn (Germany)-based team of space planners it became an art form, touting all manner of organizational benefits, and flexibility. Though speech privacy was recognized as an issue, there was no systematic approach to resolve it. Against this backdrop, five variables that would affect speech privacy in an open plan were identified and their relative contributions quantified [R. Pirn, ‘‘Acoustic variables in open planning,’’ J. Acoust. Soc. Am. 49, 1339–1345 (1971)]. This work and its impact on acoustical design of the 1970s is reviewed, as are the trends in and the failings of current open-plan design practices.
Speech privacy: New laws require changes in professional practice
Authors: Sykes David
Published: October 2013

We take privacy for granted but changing technology and heightened government security concerns have altered the landscape, putting privacy back in the headlines. Privacy laws like HIPAA, GLBA, and PIPEDA compete against tech-based crimes like identify theft as well as security, laws like the Patriot Act, Homeland Security, and FISA. What constructive role can acoustics professionals play? Speech privacy is covered by most privacy laws, explicitly or implicitly—though enforcement procedures remain unclear. But, thanks to 50 years of research and standards development, a basis for objective, measurable enforcement of speech privacy exists and will soon be integrated into professional practice by the AIA. New policies and improved understanding by architects as well as legislators, regulators, judges, lawyers, and juries are beginning to stimulate demand for speech privacy engineering services including research, measurement, design, monitoring, site certification, expert testimony, and training. The TCAAN joint subcommittee on speech privacy (soon to be an S.12 Work Group) was set up in November 2005 to lead this work. Subcommittee members are addressing two issues: Writing new Guidelines for Acoustics in Healthcare Facilities for the AIA and American Hospital Association, and developing a uniform speech privacy enforcement guideline for use in healthcare environments.
Noise in hospitals redux
Authors: Goodfriend Lewis S.
Published: October 2013

A major result of the patient survey, conducted as part of the study, Noise in Hospitals, published in 1963, and funded by the U.S. Public Health Service, was that patients in private and semi-private rooms could hear conversations from the corridor and, on occasion, discussions of their diagnosis and condition by hospital staff. Also noted was the audibility of conversations from adjacent rooms. The study covered eight eastern hospitals of varied size. The results showed background ambient sound kevels in patient rooms, in the low-to-mid 40 dB(A) range. In general, the spectra, with low mid- and high-frequency levels, show why speech in the corridor, at normal levels, was highly intelligible in patient rooms in a number of hospitals. Much of the noise in hospitals is not continuous and that which was continuous, often had undesirable spectral or cyclic characteristics that added to the annoyance of the patients, but did not interfere with speech intelligibility, even with high, annoying, low-frequency levels. More recent information from one of the original hospitals and work by others indicates that the problem of noise in hospitals has not yet been well addressed.
Quieting Weinberg 5C: A case study in reducing hospital noise on a patient ward
Authors: MacLeod Mark , West James E. , Busch-Vishniac Ilene J. , Dunn Jeffrey , Reedy Anita
Published: October 2013

Although noise in hospitals is among the top complaints of patients, visitors, and staff, little has been done to address the problem. Further, hospitals have become increasingly worried about using materials that might harbor bacteria, shunning traditional sound absorbers and making the problem even more acute. In this study, we investigated an oncology unit in a relatively new building at Johns Hopkins Hospital, with the aim of demonstrating a noise reduction. We found a series of problems at Weinberg 5C, including architectural design that focuses sound at the nurses station, hallways that create an effective waveguide around the unit, and the total absence of sound-absorbing materials. We were able to mitigate these problems through judicious placement of sound-absorbing panels on the ceiling and high on hallway walls. The panels were constructed of noncompressed fiberglass insulation wrapped in an antibacterial fabric and suspended with Velcro. Results show a drop in sound level of about 5 dB(A), a drop in reverberation time of roughly a factor of 3. A survey of patients and staff before and after the intervention shows a remarkable shift from the perception that the unit is noisy to a perception that it is reasonably quiet.
Recent advances in nanoindentation-based nanoscale dynamic mechanical analysis
Authors: Warren Oden L. , Syed Asif S. A.
Published: October 2013

Nanoindentation-based nanoscale dynamic mechanical analysis is rapidly gaining popularity as a quantitative small-volume characterization technique for soft matter such as polymers. In addition, the so-called nanoDMA technique can be coupled to scanning probe microscopy to quickly generate images showing the spatial distribution of storage and loss moduli, a time-saving advantage for the study of heterogeneous materials such as phase-segregated polymer blends. This presentation will address recent advances in nanoDMA, including instrumentation improvements, new measurement/analysis techniques, and efforts to push beyond the widely used linearized equation of motion to begin accounting for sources of nonlinearity not previously appreciated. If time permits, this presentation will also address the use of nanoDMA in combination with scanning probe microscopy for rapid screening of combinatorial polymer libraries.
Resonance ultrasound microscopy for quantitative determination of local stiffness and local damping of solids
Authors: Ogi Hirotsugu , Hirao Masahiko
Published: October 2013

Home-built resonance ultrasound microscopy is presented for quantitatively determining local Young’s modulus and local internal friction of materials. It evaluates the elastic properties from resonance frequencies and attenuation of an isolated langasite oscillator, touching the examined material. Noncontacting measurement (wireless and electrodeless) of the resonance frequency and attenuation of the oscillator has been achieved with a line antenna by the piezoelectric effect. The oscillator is supported by a fixture exactly at nodal points, and it touches the material at an antinodal point. Thus, acoustical contact on the oscillator surfaces occurs only at one point with the material, providing high sensitivity to the modulus and damping in the local area. Formulation of relationships between material’s stiffness and internal friction, and oscillator’s resonance frequency and attenuation is proposed using the generalized Hertzian-contact model. Results for polycrystalline copper, dual-phase stainless steel, and NbTi/Cu superconducting wire are shown, giving important knowledge including stiffness distribution within a crystallite. The results are compared by electron-backscattering-pattern measurements.
Dissipation mechanisms associated with atomic force acoustic microscopy
Authors: Turner Joseph A. , Stagemeyer Matthew , Shen Kangzhi
Published: October 2013

The impact of tip-sample dissipation mechanisms in atomic force acoustic microscopy (AFAM) and other techniques is evident in the width (and corresponding Q-factor) of the resonances observed. The Q-factors of resonances while in contact are often several orders of magnitude lower than those for air alone. Dependence on applied load, humidity, and vibration mode have also been observed. Here, two dissipation mechanisms are discussed with application to AFAM. First, frictional losses associated with the tip-sample oscillations are examined. The cyclic energy loss that accompanies tip vibrations is calculated for the combined normal and shear forces present during AFAM measurements using an extension of a Mindlin contact model. The dependence on mode, applied load and friction coefficient, and other parameters is seen explicitly. Second, the dissipation associated with losses from viscoelastic contact is calculated using simple viscoelastic materials models that are coupled with the vibrating-beam boundary value problem. In this case, the dependence of the dissipation on sample properties and tip geometry is determined. The role of each of these mechanisms for specific tip-sample systems is discussed. The results are expected to impact quantitative aspects of nanomechanical characterization techniques. [Work supported by ARL.]
An auditory perceptual change with repeating noise bursts
Authors: Zurek Patrick M.
Published: October 2013

This talk describes a change in perception that is experienced when listening to repeating noise bursts. When a brief (10–20 ms) frozen noise burst is presented repeatedly at a rate of about 1/s, the perceived quality of the bursts changes. Initially, the noise bursts have the expected perceptual texture of white noise (like the consonant ‘‘ch’’ spoken in isolation). At some later time, usually 10–30 s after the start, that noise texture disappears and the perceptual quality becomes that of a dull click or thump. Initial observations of this perceptual change under a variety of stimulus manipulations will be described. Unlike perceptual changes involving repeated speech (e.g., semantic satiation and the verbal transformation effect), which are usually labile and involve multiple transitions among multiple perceptual forms, the observed change with noise bursts appears (thus far) to be only a two-state, one-way change with constant stimulus repetition.
Estimating the rate of response growth using above characteristic-frequency maskers
Authors: Wojtczak Magdalena , Viemeister Neal F.
Published: October 2013

Growth of forward masking was measured to determine the relative rate of basilar-membrane (BM) response growth at the characteristic-frequency (CF) place that was stimulated with a higher-frequency tone. Two signal frequencies (fs) were used, 1 and 4 kHz. The masker frequency was 1.1fs or 1.2fs. A lower-frequency masker (0.6fs) was also used to replicate previously published data. Previous data obtained using a method for deriving the BM input-output function based on temporal masking curves suggested a linear growth of the BM response to a tone with a frequency equal or higher than 1.1fs and a compressive growth for the CF tone. This study demonstrates that the growth-of-masking method for deriving the BM response provides a similar result (indicating a compressive growth for the CF tone) when a low-frequency masker is used but leads to a fundamentally different result (indicating an expansive response growth) when a higher-frequency masker is used. The expansive growth is observed even when a low-pass noise is used to limit potential off-frequency listening. The data will be related to mechanical BM data and the equivalence of the two psychophysical methods for deriving BM compression will be discussed. [Supported by NIH Grants DC00683 and DC006804.]
Speeded detection of sound signals based on temporal differences
Authors: Suied Clara , Pruvost Laurent , Susini Patrick , Misdariis Nicolas , Langlois Sabine , McAdams Stephen
Published: October 2013

Previous research has identified acoustic parameters modulating the perceived urgency of alarms. Such approaches have focused mainly on the subjective relationship between characteristics of the alarms and the perception of urgency. We suggest that an objective measurement will ensure with more certainty the effectiveness of the acoustic parameters and will help us to understand more precisely the underlying processes. We have to the improve the ability of warning signals to increase the probability of a faster reaction under emergency conditions. Thus, we performed two experiments using a speeded reaction-time (RT) paradigm, under two tracking task conditions: motor and visual. Experiment 1 studied the influence of the tempo of the sequences. RT decreased as tempo became faster. Experiment 2 studied the influence of temporal irregularity. Outlier analyses show that RT decreased with the irregularity of the sequences. A scaled judgment of urgency was also given by subjects. Two underlying processes seem to be involved: experiment 1 highlights expectancy effects (temporal regularities provide a temporal reference frame), whereas experiment 2 emphasizes capture effects (a temporally perturbed event is more salient than a temporally expected one) [Jones, M.R., ‘‘Attention and timing,’’ in Ecological Psyhoacoustics, edited by J. Neuhoff (Elsevier Acadamic Press, San Diego, 2004) pp. 49–88 (2004)]. Moreover, comparisons between RT measurements and subjective judgments improve the validity of our approach.
Using psychometric functions to determine auditory perception of the size and speed of a rolling ball
Authors: Stoelinga Christophe , Hermes Dik , Kohlrausch Armin
Published: October 2013

The purpose of the presented experiments is to quantify exactly how precise listeners can judge certain mechanical parameters of a system by listening to the sounds generated by this system. We used sounds generated by a ball rolling over a plate. In the recording of these sounds, the ball diameter, rolling speed, and plate thickness were varied. Subjects were asked to judge each of these three parameters in the sound in two different ways; in a paired comparison, two alternative forced choice, and using absolute magnitude estimation. Both methods were used to calculate psychometric functions which estimate the probability that a listener correctly identifies the difference in one of the physical parameters. Both paired comparison and absolute magnitude estimation lead essentially to the same psychometric functions. For each pair of sounds the percentage of correct responses is plotted against the fraction of their sizes. These datapoints are then fitted to a cumulative normal distribution. The good fit of the results, using this logaritmic scale for the estimated parameter, is in close agreement with Steven’s law. This method was used to test whether if discrimination capabilities decrease when two parameters, eg. speed and size, are changed simultaneously.
Relationships of performance accuracy, target call sign sensitivity, and response bias on the Coordinated Response Measure task
Authors: Shafiro Valeriy , Gygi Brian , Snapp Hillary
Published: October 2013

Coordinated Response Measure tasks evaluate attentional processing by requiring the listener to mark the color-number response contained in a phrase that starts with a specific call sign. However, when a target call sign is present on every trial, it is not known whether subjects must perceive the call sign in order to respond correctly. The present experiment examined the relationships among sensitivity to the target call sign, response bias, and performance accuracy in 6 normal-hearing subjects over 4 testing sessions. The number of talkers (2–4) and talker sex configuration were manipulated in 9 stimulus conditions. In session 1, a target call sign was present on every trial. During sessions 2 and 4, 10% of the trials were foils with no target call sign, while the stimuli in the third session had an equal number of trials with and without the target call sign. Results indicate significant main effects of test session and sex configuration for all 3 experimental parameters. High correlations were observed between sensitivity and accuracy for all sessions. However, a significant improvement in sensitivity was not accompanied by a similar improvement in accuracy, suggesting that better call sign detection does not necessarily lead to better task performance.
Monitoring of bulk materials using ultrasonic waveguides
Authors: Lowe Michael , Cawley Peter , Simonetti Francesco
Published: October 2013

Much progress has been made in the use of guided waves for the detection of cracks and corrosion in structures such as pipelines, railway lines, and steel reinforcing tendons. The challenge with those ideas is to use waves which are sensitive to the defects and insensitive to any materials in contact with the structure. However, a complementary approach is to identify waves which are particularly sensitive to materials in contact with the waveguide and thus to identify their presence and properties. The authors have worked on a number of interesting applications of this kind, including the characterization of sludge and detection of blockages in pipelines, the in situ measurement of the material properties of soil, the monitoring of the cure of adhesives, and the measurement of the properties of complex fluids. The paper will discuss the physical phenomena which determine how the guided waves in bars, pipes, and plates are affected by materials with which they are in contact, and give examples of how these phenomena can be exploited.
Acceptable noise levels with intelligible and unintelligible primary discourse
Authors: Hickey Susan G. , Moore Robert E.
Published: October 2013

Acceptable noise levels (ANL) were assessed for 30 adult, normal-hearing listeners in sound field in three conditions. The three conditions were primary signal of (1) intelligible discourse (Arizona Travelogue); (2) unintelligible backwards discourse (Arizona Travelogue recorded backwards); and (3) unintelligible Chinese discourse. In each condition the primary speaker was male. ANL was determined for each of three conditions by having participants select their most comfortable level (MCL) for the primary discourse. Next, for each condition, speech babble was added and adjusted to find the participant’s maximum background noise level (BNL) that was acceptable while listening to the primary discourse. The ANL was determined by subtracting the BNL from the MCL. The group mean ANLs for the intelligible discourse, the backwards discourse, and the Chinese discourse were 7.16, 8.64, and 9.31 dB, respectively. An ANOVA for repeated measures indicated a significant main effect for primary discourse type (F=5.54, p=0.006). Posthoc paired samples t-tests indicated a significant difference between the intelligible and unintelligible backwards discourse condition (t=−2.47, p=0.020) and the intelligible and unintelligible Chinese discourse condition (t=−3.17, p=0.004).
Predicting changes in breathiness resulting from variations in aspiration noise and open quotient using a loudness model
Authors: Camacho Arturo , Shrivastav Rahul
Published: October 2013

Previous studies have reported that increases in high-frequency aspiration noise (AH) and open quotient (OQ) are correlated with an increase in the perception of breathiness in vowels [Klatt and Klatt, J. Acoust. Soc. Am. 87, 820–857 (1990)]. However, a system based on psychoacoustic loudness models has been shown to predict the level of breathiness in vowels to a greater extent than AH and OQ themselves [Shrivastav and Sapienza, J. Acoust. Soc. Am. 114, 2217–2224 (2003)]. The goal of this experiment was to verify the significance of AH and OQ in the perception of breathiness and to determine how each of these influences the output of the loudness model, individually and in combination. Ten vowels, five male and five female, were synthesized using a Klatt synthesizer. Each vowel was used to generate three continua varying in terms of their OQ and/or AH. Ten listeners rated breathiness for each continuum using a magnitude estimation task. Results show that normalized partial loudness as well as the loudness of aspiration noise predicted changes in breathiness resulting from an increase in AH. Increase in OQ resulted in very small changes in perceived breathiness, resulting in poor correlation with loudness measures. [Research supported by NIH/R21DC006690.]
Infant’s perception of speech in noise: Effect of the number of background talkers
Authors: Newman Rochelle S.
Published: October 2013

A number of recent studies have investigated infants’ abilities to hear speech in noise [Newman & Jusczyk, ‘‘The cocktail party effect in infants,’’ Percep. Psychophs. 58, 1145–1156 (1996); Newman, R. S., ‘‘The cocktail party effect in infants revisited: Listening to one’s name in noise,’’ Develop. Psychol. 41, 352–362 (2005); Barker & Newman, ‘‘Listen to your mother! The role of talker familiarity in infant streaming,’’ Cognition, 94, B45–B53 (2004); Hollich, et al., ‘‘Infants’ use of synchronized visual information to seperate streams of speech,’’ Child Develop. 76, 598–613 (2005)]. In the current study, we examine how the type of background noise influences infants’ ability to understand speech. Infants aged 5 months heard a talker repeat either their own name or another infant’s name in the presence of one of 3 types of background noise: multitalker babble, a single background talker, or a single talker reversed in time. With multitalker babble, infants could recognize their name (shown by longer listening to own-name than other-name test trials) only when the target speech was at least 10 dB more intense than the background. However, even at this high SNR, infants fail to recognize their name when the background consists of a single talker. This difficulty is not the result of semantic information or speechlike properties from the single talker; infants likewise fail when the single talker is temporally reversed. Rather, infants appear to be distracted by signals containing the time-varying amplitude patterns of a human voice, and do not appear to benefit from the dips in noise amplitude that occur with a single voice.
Acoustics of clear speech from children with normal hearing and cochlear implants
Authors: Lotto Andrew J. , Ide-Helvie Dana L. , McCleary Elizabeth A. , Higgins Maureen B.
Published: October 2013

It is common among clinicians to ask children to produce their best speech during intervention. However, it is unclear whether children know how to respond to these directions and whether any contingent changes in their production actually result in better speech. Normal and best speech for children with normal hearing (NH) and cochlear implants (CI) were compared on a variety of acoustic measures. The children (7 to 14 years of age) were asked to read ten simple sentences to train up a fictional automatic speech recognizer for children. They subsequently produced the same sentences with their best and then very best, very clearest speech (ostensibly to test the recognizer). Sentence, pause, and vowel duration were calculated for all sentences as well as vowel intensity and fundamental frequency. Additionally, phonetic distinctiveness was evaluated through vowel space size and voice onset time differences between voiced and voiceless stops. NH children demonstrated patterns of best speech that resemble adult clear speech productions. CI children’s speech resembled NH best speech in all elicitation conditions, except that they slowed (their already slower) speaking rate for best speech. The results indicate that clear speech can be produced by children. [Work supported by NIH.]
Bayesian model comparison and selection in energy decay analysis of acoustically coupled spaces
Authors: Jasa Tomislav , Xiang Ning
Published: October 2013

The use of Bayesian inference in problems of parameter estimation from noisy data and in uncertain environments has been well discussed in the acoustical signal processing literature. In many acoustical problems where it is uncertain which suitable model among a set of competing ones should be used, the model comparison and selection become crucial prior to the actual parameter estimation. However, tools for model selection in Bayesian inference have received less attention. In problems of model comparison and selection, the Bayesian methodology is most different from orthodox statistical methods. We present several methods for model comparison and selection from a Bayesian viewpoint and demonstrate their application to the problem of estimating the number of decay rates present in acoustically coupled spaces.
A comparison of behavioral and auditory brainstem response measurements of absolute and masked auditory thresholds in three species of birds
Authors: Noirot Isabelle C. , Brittan-Powell Elizabeth F. , Dooling Robert J. , Montgomery Lindsay
Published: October 2013

Auditory brainstem responses (ABRs) were used to measure auditory thresholds for pure tone in quiet and in noise for three species of birds: budgerigars (Melopsittacus undulatus), canaries (Serinus canarius), and zebra finches (Taeniopygia guttata). ABRs were recorded in response to 5-ms pure tones at frequencies between 500 and 8000 Hz. Results showed that the shape of ABR audiograms generally paralleled the shape of behavioral audiograms but ABR thresholds were generally 20 to 40 dB higher than those obtained behaviorally. ABR thresholds in noise were also measured at frequencies between 1000 and 4000 Hz. Three different levels of broadband white noise were used and critical ratios (CR; signal-to-noise ratio at masked threshold) were calculated. In general, CRs were independent of the level of the masking noise, in good correspondence with behavioral data. While CRs across a wide variety of vertebrates show a 3-dB/octave increase, CRs in these birds were similar or better at 2860 Hz than 2000 Hz, and worse at 4000 Hz. To the extent that these relationships between behavioral and ABR thresholds are generalizable across species, ABR measurements can be used to calculate audiograms and CRs in species that cannot be tested behaviorally. [Work supported by DC00198, DC04664 to R.J.D.]
The performance of a newly developed mobile hands-free context-aware communications system in a hospital environment
Authors: Atkins Joshua D. , Sammon Michael J. , Brotman Lynne S.
Published: October 2013

This paper characterizes the effect of hospital noise conditions on a mobile communications system developed for a research trial in a Johns Hopkins Hospital nursing unit. The system provides an alternative to telephones and overhead paging in hopes of reducing the amount of noise on the hospital unit. Benefits of this system over current similar solutions include a completely hands free approach using a computerized voice agent and a design that addresses privacy concerns to comply with HIPAA requirements. The nurses were happy with the system and bypassed the phones and overhead paging in preference of their headsets. However, during the system trial, the effect of noise on the automatic speech recognition (ASR) engine from sources like alarms, medical equipment, and wind noise from mobile users was an issue. Utterance tests were run using a variety of different Bluetooth headsets to measure the impact of various noise sources, S/N, and noise reduction algorithms on ASR performance. Common noise reduction methods were not helpful for the type of noise encountered, suggesting that solutions such as noise robust speech systems and noise reduction with adaptive microphone arrays currently being researched will be of great importance to future systems of this kind.
The role of sound masking treatment in the value engineering of office designs
Authors: Horrall Thomas , Rosenberg Carl
Published: October 2013

For over 50 years sound masking systems have often been included in the design and planning of office spaces because the owner understood that they are required to provide adequate speech privacy, or because he believed they can create a more pleasing and private acoustic environment. However, installations have rarely been considered on the basis of project value engineering or return on investment. In this paper, we argue that sound masking systems should in fact be considered not only as a stand-alone cost component of the office design, but evaluated along with ceiling tile, private office wall construction, and workstation design for their mutual impact on the overall project budget, instead of solely on their contribution to acoustical performance. With over 70 years of combined experience dealing with speech privacy issues and masking systems of all kinds, we provide typical project data to demonstrate that contemporary systems often can result in substantial overall project cost savings.
Approximating acoustic field uncertainty in underwater sound channels
Authors: James Kevin R. , Dowling David R.
Published: October 2013

Precise acoustic field prediction relies on accurate knowledge of many environmental parameters. Uncertainty in any of the inputs to a propagation routine leads to uncertainty in the predicted field. The most accurate but time-consuming method of assessing the resulting field uncertainty is Monte Carlo simulation, which requires calculating the field with many possible combinations of inputs. This presentation covers a method to approximately determine the uncertainty in the predicted field, using only one additional field calculation for each uncertain parameter, when the input uncertainties are relatively small. The method relies on identifying how variations in uncertain input parameters can be mapped into spatial displacements in the original field calculation. Simultaneous uncertainty in multiple input parameters is handled using a net effective spatial displacement. In addition to expected values and standard deviations, the method allows for the generation of complete probability density functions for the uncertain predicted field. Calculated field amplitude results for both ideal and more realistic range-independent sound channels having small depth and sound speed uncertainty are shown and compared to Monte Carlo simulations at several source-receiver ranges. [Work sponsored by the Office of Naval Research, Code 321OA.]
Adaptive sampling based on the waveguide invariant for determining environmental provinces
Authors: Leclere James H. , Smith George B.
Published: October 2013

The waveguide invariant (related to the striations seen in range-frequency plots of sonar data) can be used as a tool to determine provinces in adaptive sampling schemes used to plan the placement of environmental measurements. The quantity from which the waveguide invariant is derived is used to demark spatial regions over which the environment can be considered to be range and bearing independent from an acoustic point of view. This allows significant speedup in acoustic propagation calculations. It also provides guidance for the placement of environmental measurements—particularly water column sound speed profile measurements. Results from the application of this technique to simulated data and to data from the Sea of Japan are shown and are compared to results of another method based on the adiabatic condition. [This work was supported by ONR with technical guidance provided by the Naval Research Laboratory, Stennis Space Center, MS.]
Vis-a-vis (2002), Katherine Bergeron, voice
Authors: Rovan Joseph
Published: October 2013

What is the cause, and the cost, of insight? What does it mean to see the world face to face? These questions were raised by the young Rainer Maria Rilke in a passage from his Notebooks of Malte Laurids Brigge, a journal he kept in 1904 while serving as secretary to the sculptor Rodin. They also lie at the heart of Vis-a-vis, a multimedia work for voice and computer music soundscape, which takes Rilkes words as a dramatic point of departure. Recalling an encounter with a nameless woman in the streets of Paris, Rilke’s text is a meditation on the nature of faces. It reads like a drama, a story in five virtual scenes told from multiple points of view and in several voices, alternately droll, philosophical, ironic, pathetic. In this new 5.1 mix the multivocal and multilingual aspects of Vis-a-vis are highlighted through the use of acousmatic space; the aim is to suggest the shifting psychological relationship between the woman who sings and the nameless woman who is the subject of Rilkes narration.
Convergence
Authors: Carballeira Andrew
Published: October 2013

In the words of Mahatma Gandhi, ‘‘We must become the change we wish to see in the world.’’ Exploitation, racism, violence, and militarism are all the rage in our world today. Persons of conscience opposed to this intoxicating madness are charged with envisioning something better. This piece is one in a series of attempts to draw a ray from our current predicament to a world free of war and racism. It opens with highly disjointed, atonal interactions physically separated in space. As the piece evolves, the voices begin to move together and speak more consonantly with each other: an aural simulation of the world uniting around the principles of peace, justice, and equality.
Untitled Number 3
Authors: Clifford Andrew , Cohn Eli D. , Mallory Robert M. , Case Alexander U.
Published: October 2013

Untitled Number 3 was written and performed by Sparrows Swarm & Sing in 2005 and 2006. The work is a postrock instrumental for cello, violin, percussion, distorted electric guitar, rock drums, voices, handmade noisemakers, and digital signal processors. Composition is a collaborative process that occurs through both live improvisation among the six-piece ensemble and deliberate experimentation, rehearsal, and overdubbing.
‘‘Thaw/Twist at Bailey’s.’’
Authors: Moore Stephan
Published: October 2013

A field recording of the 2004 spring thaw at Thomas Bailey’s farmhouse in Richland, MI is used to explore the phenomena of temporal/spatial convergence and dispersal, as it can be used to manipulate and disorient our perception of location. Originally composed for a site-specific 16-channel array of custom-built speakers, this piece has been adapted to standard 5.1 surround sound. Duration: approximately 9 min.
Power chords, polyphonic trains, and plain old phase
Authors: Moulton David
Published: October 2013

Power chords, polyphonic trains, and plain old phase is a 36-min work of music composed directly for a six-channel array of loudspeakers (reduced to 5 channels for this performance). This piece draws on the work of minimalist sculptors such as Donald Judd and Michael Heizer, and explores the evolving nature of slowly shifting phase, reverberation, and the sonic continuum, using extremely simple sonic materials.