bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of microphone frequency response and windscreen insertion-loss corrections on sound power determinations.
Authors: Ristroph Einar , Black Michael , Phillips John
Published: March 2010

Engineering-grade product noise emission testing programs are qualified, and correction factors are applied to test results, based on “known” sound power levels of a reference sound source; i.e., a sound source that has been tested and qualified in accordance with ANSI S12.5/ISO 6926. The accuracy and uncertainty of ANSI S12.5/ISO 6926 test results are then transferred to the engineering-grade testing program and are thus of crucial importance. ETS-Lindgren recently commissioned the new Acoustic Research Laboratory at headquarters in Cedar Park, TX, and is developing an ANSI S12.5/ISO 6926 reference sound source testing program. This work included evaluation of factors contributing to accuracy and uncertainty. The application of microphone frequency response corrections (obtained from outside calibration laboratory) is discussed and data are presented. In addition, the use of windscreen insertion-loss corrections is discussed and data are presented.
Exposure to recreational/occupational shooting range noise versus industrial impulsive noise.
Authors: Marlund Hale
Published: March 2010

Public shooting ranges are used primarily for recreational shooting. Certain occupations require periodic certification of firearms proficiency. Single gunfire noise is loud and impulsive. However, both recreational and occupational proficiency shooters are often exposed to firearm noise from other shooters. In such cases, the shooting noise exposure can include gunfire impulses less than 1 s apart. This situation changes noise exposure from “impulsive” to “continuous” during each open-fire session. A similar situation occurs in industrial applications when the work process involves impulsive fastening activities, such as pneumatic riveting. The similarities in high-intensity noise exposure at busy shooting ranges and production line riveting include time-weighted averages, under the current OSHA regulations, that are less than 90 dB(A) but consistently exceed 140 dB(C) peak. As a result, even though firing range and workplace rules require the use of hearing protection, it is not uncommon for recreational or occupational shooters and industrial workers to be casual about the fitting and proper use of their hearing protection devices. This paper describes the similarities in daily impulsive noise exposure at the shooting range and fastening production line. It also discusses the potential dangers in both situations with ill fitting and best practice use of hearing protectors.
Vibration transfer path analysis on fender noise control.
Authors: Liang Paul
Published: March 2010

The fender is one of the major noise radiators in motorcycles. The source of the fender noise comes primarily from the engine vibration through the vehicle frame. A rubber isolator between the engine and frame can effectively break the vibration path, thus reducing the fender noise. A finite element method will be used to analyze the vibration transfer paths of an engine and a boundary element method will be used to predict the radiated noise from the rear fender.
Quasi-wavelet cascade models for intermittent random media and application to wave scattering.
Authors: Wilson D. Keith , Ostashev Vladimir E. , Goedecke George H. , Ott Soren , Albert Donald G.
Published: March 2010

Terrestrial environments often possess intermittent distributions of scattering objects. Examples include atmospheric turbulence, subsurface geology, vegetation, and buildings. A quasi-wavelet (QW) cascade process model for such intermittent random media is described, and the implications for wave scattering are examined. The QW model builds the random medium from randomly positioned and oriented, wavelet-like entities, which follow prescribed distributions for number density and energy vs spatial scale. Different types of QWs, including monopole and dipole scalar fields and toroidal and poloidal vector fields, can be combined with statistically preferred orientations to create multiple field properties possessing correlated properties and anisotropy. The spatially localized nature of the QWs facilitates construction of intermittent random fields in a manner that would be extremely challenging, if not impossible, with conventional Fourier approaches. To test the QW model, we conducted a seismic propagation experiment in the vicinity of a volcanic crater in the Mojave Desert. This site was chosen for its highly inhomogeneous, intermittent distribution of basalt and sand. Propagation of impulse signals was sampled along 864 distinct paths. Statistical distributions of seismic travel times were simulated with good success using a finite-difference, time-domain method applied to a QW model for the site geology.
Effect of combined noise sources on cognitive performance and perceived disturbance.
Authors: Jeon Jin Yong , Lee Pyoung Jik
Published: March 2010

An experiment was conducted to investigate the differences in cognitive performance and perceptions under road traffic noise and construction noise combined with road traffic noise. Under the conditions with individual noise and combined noise sources, an episodic memory task and semantic task were carried out in the laboratory. The subjects were asked to recall the presented words after the exposure to noises (episodic memory task) and to select the target word when the five words, including the target word and other words, were presented simultaneously (semantic memory task). Subjects also rated perceived annoyance and disturbance to the noise exposure during the experiment. The result showed that the percentage of correct answer significantly decreased with an increase in construction noise in an episodic memory task. In contrast, the semantic memory task was not impaired by the level of construction noise level. This indicates that only the retrieval task with a process of generating the internal cues was affected by the level of combined noise sources. And it was also found that the perceptions of combined noise sources were highly correlated with the result of the episodic memory task.
Standardizing the measurement of natural and urban soundscapes.
Authors: Kull Robert
Published: March 2010

For the purpose of discussion, a simple model was presented to illustrate the contributions and interactions of various elements within an environment that make up soundscapes [Kull (2006)]. These elements should be considered when attempting to characterize a soundscape using acoustic measurements. For this presentation, the model will be used with the objective of creating a plan for taking sound measurements.
Marine mammals and anthropogenic noise: Challenges from a management and regulatory prospective.
Authors: Scholik-Schlomer Amy R. , Guan Shane , Harrison Jolie , Johnson Craig
Published: March 2010

Responsibilities of the National Marine Fisheries Service (NMFS) include conserving and recovering marine species protected under the U.S. Marine Mammal Protection and Endangered Species Acts. One of our primary objectives is to assess the risks anthropogenic noise in marine/coastal environments poses to animals in those environments and implement appropriate measures to reduce these risks. Many challenges to achieving these goals exist from both a scientific and a regulatory perspective. Accounting for the inherent complexity of source characteristics, noise propagation through the environment, and temporal/spatial overlap between sources and protected species, as well as understanding how noise exposure affects species are often quite difficult. Exposures typically are either high-level, short-term (e.g., seismic survey), or lower-level, long-term (e.g., construction project), with each presenting different risks. Establishing appropriate metrics for describing noise sources, assessing effects on individuals and on populations/stocks, as our statutes require, and ensuring the practicality of applying these metrics to real-world situations are essential. There are also often considerable data gaps, which require us to draw upon the knowledge gained from human and other terrestrial species. NMFS is currently re-evaluating and updating our acoustic criteria, which are used within our impact assessments, to reflect the best-available science on these issues.
Evidence-based medicine meets evidence-based design: An interdisciplinary study of acoustics and sleep disruption as a context for improving teamwork.
Authors: Solet Jo M.
Published: March 2010

Hospital noise-induced sleep arousal probability curves were derived by exposing laboratory monitored sleeping human subjects to 14 common stimuli selected and scaled from a recorded inpatient hospital sound-scape. The research process in this recently published successful project, which informed the 2010 Guidelines for the Construction of Health Care Facilities, serves as a context for discussion of the promise and pitfalls of interdisciplinary teamwork, bringing together evidence-based medicine and evidence-based design, to solve real world problems. Revealing normally unspoken professional assumptions, work ethics, record keeping requirements, and conflict of interest concerns, this program seeks to make cross field boundary breaking collaboration easier and more successful and to improve possibilities for meaningful innovation. [Work supported by AAHF, FGI, and CHD.]
Acousto-optics as the background of a long-lasting friendship with Mack Breazeale.
Authors: Leroy Oswald
Published: March 2010

Ever since I have known Mack Breazeale, our friendship has come along with discussions and bilateral suggestions for further research in acousto-optics. Among many other topics we had a common interest in the application of acousto-optics for nondestructive testing. For layered structures all information concerning the structure is contained in the phase information of the ultrasound investigating the material. This phase information is obtained using two or only one laser beam depending on the kind of required information. Using the technique of two laser beams the measured phase difference between the incident and the reflected ultrasonic beam is influenced by the geometrical shape of a plate, the thickness of a thin layer on a substrate, as well as by the presence of defects inside a layered material. In addition different methods are discussed to describe the diffraction of light by monofrequent, pulsed, and adjacent superposed ultrasound. In the optical nearfield of a diffracted laser beam, it is even possible to reconstruct all of the acoustic wave parameters. The ability of measuring the amplitude and phase of reflected and transmitted waves is a powerful tool to discover information about the surface on which scattering of sound occurs.
Nonlinear interaction of ultrasonic waves: A tribute to Mack Breazeale.
Authors: Korman Murray S.
Published: March 2010

While at Brown University (∼1977), this graduate student was fortunate enough to learn about Mack Breazeale’s important early work in nonlinear ultrasonic waves in solids [J. Appl. Phys. 36, 3486 (1965)] through his thesis advisor (R. T. Beyer), who had friendly and most collegial interactions with Mack, through the ASA. When I met Mack Breazeale at ASA Meetings, he would discuss how he made some of his measurements and helped me understand some complexities involving the scattering of sound by sound. While Mack Breazeale was Associate Editor of nonlinear acoustics he gave a wealth of good advice (over a period of several years) on how to improve a manuscript on crossed beam scattering in turbulence and divide the material into at least two parts—which was done. When the paper was out, one agreed with Mack that it was much better and worth the effort. Years later, doing summer research at NCPA, Mack helped improve a manuscript on nonlinear acoustic landmine detection. As a tribute to Mack Breazeale, his work on “Quantum mechanical theory on nonlinear interaction of ultrasonic waves” (with I. L. Bajak) [J. Acoust. Soc. Am. 68, 1245 (1980)] will be discussed in some detail.
Ultrasonics in solids with frequency-dependent nonlinearity parameters.
Authors: Elmore Paul A.
Published: March 2010

This paper reviews the current state of modeling the nonlinear generation of second-harmonic ultrasonic waves in heterogeneous solids. Experiments measure the rate in which the higher-order harmonics grow with wavenumber, k, and propagation distance, a. The lowest-order nonlinearity parameter, quantifying the growth rate of the second-harmonic amplitude, A2, experimentally is β∝limA1→0(A1/A22k2a), where A1 is the fundamental harmonic amplitude. In crystals and amalgamated metals, β is constant, and the corresponding equation of motion can be written with one nonlinear term to a good approximation. In heterogeneous materials with granular contacts, however, such as lead-zirconate-titanate (PZT) and graphite-epoxy composites, β changes with wavenumber, and the corresponding equation of motion requires more nonlinear terms. An equation of motion updated from the one for crystals does provide predictions of β that appear to match the experimental results; however, it is inadequate for providing velocity predictions in graphite-epoxy composites, where there is significant dispersion, and does not explicitly account for the hysteric behavior of grain contacts. A recent model that accounts for grain contacts asserts that it can account for the frequency dependent β. This paper will review these models and compare predictions for β with PZT and composites data.
Comodulation masking release with signal-masker interactions represented in the envelope.
Authors: Pierzycki Robert H. , Seeber Bernhard U.
Published: March 2010

In normal hearing, the threshold of a tone masked by a modulated narrow-band on-frequency masker (OFB) can be reduced if correlated modulation is present on spectrally distant flanking bands (FBs), an effect known as comodulation masking release (CMR). Since electric hearing with current cochlear implants is based on envelope information, comodulation of envelopes on multiple electrodes might also be beneficial for detection in electric hearing. CMR was investigated with normal-hearing participants listening to unprocessed or vocoded stimuli. In Experiment 1, tone thresholds were determined when masked by a sinusoidally amplitude-modulated band of noise (SAM and OFB) and by zero to four FBs of noise whose envelopes were either co- or anti-modulated with the OFB envelope. In Experiment 2, envelopes of those signals were extracted in a vocoder and used to modulate noise or sinusoidal carriers, thereby replacing the original temporal fine structure (TFS). Significant CMR of 3–10 dB was found in unprocessed conditions and although reduced to 2–6 dB, CMR was still significant after vocoding. CMR did not differ significantly between the sine and the noise vocoder, suggesting that the applied SAM determined the magnitude of CMR. Since CMR withstands vocoding, comodulation is hoped to improve detection in electric hearing.
Discrimination of repetitive intervals by younger and older listeners.
Authors: Fitzgibbons Peter , Gordon-Salant Sandra
Published: March 2010

The study measured listener sensitivity to increments in the inter-onset intervals (IOIs) separating successive 20-ms 4000-Hz tone bursts in isochronous sequences. Stimulus sequences contained from 2–6 tone bursts, separated equally by IOIs in the range of 25–100 ms across stimulus conditions. Difference limens (DLs) for increments of all tonal IOIs were measured to assess listener sensitivity to changes in sequence rate. A DL was also measured for increments of a single IOI located at a fixed position within 6-tone sequences. Listeners included younger and older normal-hearing adults and older adults with high-frequency hearing loss. The results revealed that the relative DLs for sequence rate decreased as the magnitude of the reference IOI and the number of sequence components increased. The relative DL for a single interval embedded within a six-tone sequence was smaller than corresponding DLs measured with two-tone sequences, but only for brief reference IOIs. The discrimination performance of the older listeners was poorer than that of the younger listeners, especially for two-tone sequences with the shortest reference IOIs. The findings are interpreted within the context of multiple-look mechanisms and possible age-related differences in the sensory coding of signal onsets. [Research supported by the National Institute on Aging, NIH.]
Interaural time difference thresholds as a function of the duration of the beginning of a sound in hearing-impaired adults.
Authors: Akeroyd Michael A. , Guy Fiona H.
Published: March 2010

The precedence effect indicates that the auditory system places most weight on spatial information at the onset of a sound. In this experiment, we measured how well hearing-impaired adults can ignore what comes immediately after the onset of a sound, as any limitations in that should interfere with localization in environments with lots of reflections. The stimulus was designed to be a simplified analog of a room impulse response: it consisted of two bursts of speech-shaped noise concatenated together: the first was short and given some ITD (representing an ideal onset that marked direction correctly), but the second was far longer and was interaurally uncorrelated (representing later reflections and reverberation from all possible directions). We measured psychometric functions (over the ITD and duration of the first burst) to determine the minimum duration of the first burst needed to report its direction. Presently, 19 listeners have completed the task. No significant correlation was found between minimum first-burst duration and hearing loss (better-ear loss = 3–50 dB), but the individual variation was considerable, especially so in those listeners with larger hearing losses. The results indicate that some listeners will have difficulty in ignoring irrelevant information after a sound’s onset.
Effects of independent bilateral compressive amplification on lateralization of a single source.
Authors: Wiggins Ian M. , Seeber Bernhard U.
Published: March 2010

Use of compressive amplification in bilateral hearing aid fittings can disrupt binaural cues important to spatial hearing. The head-related transfer function introduces direction-dependent interaural time and level differences (ITDs and ILDs) which are consistent with one another. Independent bilateral compression, however, reduces ILDs such that they suggest a different, conflicting direction than ITDs. The reduction in ILDs is a dynamic effect that depends on the characteristics of the compression and the sound. Single-channel compression was applied over a wide, high-frequency band. Two conditions were run, with the high-frequency channel presented to listeners in isolation or recombined with an unprocessed low-frequency channel. Stimuli included pink noise bursts with varied onset slopes and rates of amplitude modulation and speech. The effects of compression on the perceived auditory objects were assessed using a semantic differential method, in which listeners rated various spatial attributes on scales between two bipolar adjectives, for example, image width was rated on a scale between “focused” and “diffuse.” Additionally, a lateralization task was performed. Initial results show that for sounds with slow onsets, compression tends to shift image location or causes the image to split. Interestingly, image location can also be affected for speech, particularly if high-pass filtered.
Effect of waveform shape and polarity on loudness and on place pitch for cochlear implant users.
Authors: Carlyon Robert , Macherey Olivier , Deeks John
Published: March 2010

It has been shown that, for pseudomonophasic pulses presented in monopolar mode, less current is needed to achieve the same loudness when the short-high phase is anodic than when it is cathodic. Experiment 1 extended that finding, obtained with the Advanced Bionics (AB) device, to waveforms that can be implemented in other devices, using 99-pps, 32-μs/phase pulse trains. For AB and MedEl devices, stimuli were triphasic pulses whose central phase had twice the amplitude of the first and third phases. For the Nucleus device, stimuli were pairs of biphasic pulses with opposite leading polarity, each with a 58-μs interphase-gap, separated by 8 μs—resulting in two adjacent same-polarity phases in the center of the waveform. The current level needed was always 1–2 dB lower when the central portion was anodic than when it was cathodic—including for electrode 1 of the MedEl device, which is inserted deep into the cochlea. Experiment 2 showed that, for pseudomonophasic pulses in bipolar mode, (a) pitch is lower when the “short-high” pulse is anodic relative to the more-apical than to the more-basal electrode and (b) intermediate pitches can be produced by variations in waveform shape and polarity applied to the same bipolar pair.
Noise-suppression algorithms for improved speech intelligibility by normal-hearing and cochlear implant listeners.
Authors: Loizou Philipos
Published: March 2010

Much research in the past few decades focused on the development of noise reduction algorithms that can suppress background noise. While these single-microphone based algorithms have been proven to improve the subjective speech quality, they have not been effective in improving speech intelligibility. This is partly due to the fact that most noise-suppression algorithms introduce speech distortion and partly because most algorithms are not optimized to operate in a particular noisy environment. Furthermore, none of the existing noise-reduction algorithms was designed to optimize a metric that correlates highly with intelligibility. This talk will present intelligibility data collected with normal-hearing and cochlear implant listeners who were presented with noisy speech processed by environment-optimized algorithms. It will also present algorithms that were designed using metrics that correlate highly with speech intelligibility. The data from these studies suggest that it is possible to develop noise reduction algorithms that improve speech intelligibility provided some constraints are imposed on the design of the suppression function and/or the intended listening environment. Research supported by NIDCD/NIH.]
Subjective evaluation of the speech quality from speech enhancement and segregation algorithms.
Authors: Mahadevan Vijay , Vishnubhotla Srikanth , Espy-Wilson Carol
Published: March 2010

Automatic separation of speech from noise and segregation of overlapping co-channel speech are two of the most challenging problems in speech processing. In previous work, we have developed algorithms to both enhance noisy speech and segregate overlapping speech streams. Our single-channel speech enhancement and speech segregation algorithms have shown better performance than other reported algorithms for automatic speech recognition. Additionally, objective evaluation scores of perceptual quality have shown a significant improvement following processing by our algorithms. In this study, we focus on subjective evaluation of these algorithms for human listeners. We investigate the intelligibility and quality of speech from our algorithm on normal-hearing listeners, cochlear implant users, and hearing impaired subjects. Our preliminary results indicate a significant improvement in the perceptual quality of the speech signal after being processed by our algorithm and suggest that the proposed algorithms can be used as a pre-processing block within the signal processing in hearing aid devices.
Synthesizing speech from surface electromyography and acoustic Doppler sonar.
Authors: Toth Arthur R. , Wand Michael , Jou Szu-Chen Stan , Schultz Tanja , Raj Bhiksha , Kalgaonkar Kaustubh , Ezzat Tony
Published: March 2010

Numerous techniques have been devised to process speech audio in noise, but automatic speech recognition is difficult when the noise is too great. An alternative approach is to collect data that represent the speech production process but is less affected by noise in the speech audio range. Two such types of data come from surface electromyography (EMG) and acoustic Doppler sonar (ADS). EMG records muscle activation potentials. ADS records reflected ultrasound tones. Both can be used to measure facial movements related to speech, but they present their own challenges for automatic speech recognition. This work investigates the alternative approach of using these data sources for speech synthesis. The synthesis techniques explored in this work are based on Gaussian mixture model mapping techniques, which are commonly used for voice transformation. Voice transformation is traditionally concerned with changing the identity of speech audio signals, but others have demonstrated that such techniques can be used to transform different types of signals, such as non-audible murmur and electromagnetic articulography, to speech. This work demonstrates that such techniques also show promise for transforming EMG and ADS signals to speech.
Relevant spectro-temporal modulations for robust speech and nonspeech classification.
Authors: Nemala Sridhar Krishna , Elhilali Mounya
Published: March 2010

Robust speech/non-speech classification is an important step in a variety of speech processing applications. For example, in speech and speaker recognition systems designed to work in real world environments, a robust discrimination of speech from other sounds is an essential pre-processing step. Auditory-based features at multiple-scales of time and spectral resolution have been shown to be very useful for the speech/non-speech classification task [Mesgarani et al., IEEE Trans. Speech Audio Process. 10, 504–516 (2002)]. The features used are computed using a biologically inspired auditory model that maps a given sound to a high-dimensional representation of its spectro-temporal modulations (mimicking the various stages taking place along the auditory pathway from the periphery all the way to the primary auditory cortex). In this work, we analyze the contribution of different temporal and spectral modulations for robust speech/non-speech classification. The results suggest the temporal modulations in the range 12–22 Hz, and spectral modulations in the range 1.5–4 cycles/octave are particularly useful to achieve the robustness in highly noisy and reverberant environments.
The cooperative array performance experiment: A joint China-US vector field experiment.
Authors: Rouseff Daniel , Wang Zhongkang , Zhou Shihong , Meng Hong , Zhou Lisheng
Published: March 2010

The cooperative array performance experiment (CAPEx) was performed in Lake Washington near Seattle in September 2009. Acoustic transmissions in the 1.5–4 kHz band were recorded simultaneously on two vertical arrays: one a conventional 32-element pressure-sensor array and the other an 8-element array that measured both pressure and the three orthogonal components of acoustic particle velocity at each element. The present talk is an overview of both the data collected and the hardware used during CAPEx. Data were collected on the stationary arrays for both stationary- and towed-source scenarios in water 60 m deep. The source-receiver range varied between 10 m and 4 km. The data collected at short range demonstrate the relationship between the pressure and particle velocity fields. At more distant ranges, the particle velocity data are used to estimate the bearing to the source. Experimental results are compared to predictions generated using numerical models. [Work supported by ONR.]
A particle velocity gradient beam forming system.
Authors: de Bree Hans-Elias
Published: March 2010

The topic of this paper is the determination of the acoustic source distribution in the far field with a small, three dimensional (3-D) system consisting closely spaced sound pressure sensitive microphones and particle velocity sensitive Microflown. Sound pressure sensors do have a zero order directionality (that is, no directionality). Particle velocity vector sensors have a first order directionality (this is a cosine shape directionality). With two closely spaced zero order sensors, a first order system can be created. Disadvantages are the low sensitivity for low frequencies and a limited high-frequency response. With two closely spaced first order sensors, a second order system is created. The directionality is a squared cosine shape. With this higher directivity it is possible to create a very small 3-D beam forming system with a reasonable resolution which is the topic of this paper. A second order system can be made with accelerometers or pressure sensors; however, the low-frequency response is very poor. The Microflown has a very high sensitivity at low frequencies so the velocity gradient signal is good. In this paper the velocity gradient method is presented, and a 3-D velocity gradient system is demonstrated.
Low background noise is needed for good student-to-student classroom communication.
Authors: Lubman David
Published: March 2010

ANSI standard S12.60 requires that background noise not exceed 35 dBA in unoccupied lecture classrooms. Despite the strong and broad research basis for ANSI’s 35-dBA requirement, some classroom noise guidelines permit 45 dBA (notably California Collaborative for High Performance Schools and Leadership in Energy and Environmental Design). How did this come about? The 45-dBA limit was a compromise between the 50-dBA guidelines then prevailing and ANSI’s 35-dBA limits. There is no audiological basis for a 45-dBA BNL limit. With 45-dBA BNLs, the speech to noise ratio (SNR) in the rear of small classrooms is well below the 15-dB minimum required for sustained learning. With 35-dBA BNLs, the SNR approaches ANSI’s 15-dB minimum. It is underappreciated that BNLs of 35 dBA or less also promote better student-to-student (STS) communication. For every 10 dB of background noise reduction, the physical range of STS communication increases by a factor of about 3.16, and the floor area encompassed increases by a factor of 10. As BNL is reduced, eventually all classroom occupants are within communication range.
Effects of noise type and signal-to-noise ratio on speech intelligibility and the speech transmission index.
Authors: Secules Stephen D.
Published: March 2010

The STI metric is the most reliable measure we have for assessing the intelligibility of speech in public address/voice alarm or speech reinforcement systems. A good design for speech is based on an understanding of the room acoustics and electroacoustics of the system, with a consideration for the expected signal to noise ratios in the room. In modeling, most noise signals are assumed to be broadband, whereas in reality the noise signals can be significantly variable in the frequency and time domain, which may dramatically increase or reduce the intelligibility. This study compares the effects of type of noise on intelligibility as measured through both word scores and STI. It explores masking from both theoretical and real world signals. The determined relationships will help inform the design process by clarifying the effects of non-broadband and variable noise signals on intelligibility.
Verifying speech intelligibility in classrooms.
Authors: Wowk Roman
Published: March 2010

Classroom speech intelligibility has undoubtedly become a hot topic and is capturing attention on all fronts. While there has been widespread adoption of many new guidelines and standards, even the most precise initiatives will not reach their full potential if speech intelligibility is not directly verified in classrooms after they are built. Performance verification ultimately encourages a better final product and provides crucial measured data for validating design methods. To ensure measurable performance, criteria would have to be established at the outset of the design using a metric directly related to speech intelligibility such as speech transmission index. Current guidelines generally focus on reverberation time (RT) and background noise for improving speech communication in classrooms. While low background noise is a necessary component for speech intelligibility, there is not always a direct correlation between RT and speech intelligibility. For instance, improper placement of absorptive treatments for reverberation control could eliminate early supporting reflections which are beneficial for speech intelligibility. With computer modeling becoming widespread and relatively inexpensive, designing directly for speech intelligibility is becoming more practical. This paper explores case studies and examines the overall process for optimizing speech communication in classrooms with an emphasis on performance verification.
Combining visual and fixed passive acoustic methods to measure annual variability of cetacean occurrence at the NE-coast of Iceland.
Authors: Magnusdottir Edda E. , Rasmussen Marianne H. , Lammers Marc
Published: March 2010

In order to measure cetacean occurrence at the NE-coast of Iceland, two seabed-mounted Ecological Acoustic Recorders (EARs) were deployed in Skjálfandi Bay in September 2008, deployments will continue throughout September 2010. To obtain species confirmation, visual observations were conducted from a lighthouse in October 2008 to September 2009 with total observation effort of 202 h. With visual observations, the aim was to acquire background information on the cetacean sighted in the area to improve the estimates of occurrence in continued long-term passive acoustic recordings in Icelandic and adjacent waters. Movements and locations of the animals were recorded using a theodolite and a real-time mapping program (CYCLOPS TRACKER). Visual observations included sightings of blue whales (Balenoptera musculus), Humpback whales (Megaptera novaeangliae), Minke whales (Balaenoptera acutorostrata), white-beaked dolphins (Lagernorhynchus albirostris) and killer whales (Orcinus orca). A custom MATLAB program is used to automatically detect and analyze target biological sounds produced by cetaceans or by pelagic fish recorded on the EARs. The visual data are compared to the occurrence of identified sounds in order to better understand the vocal activity and average silence periods of the cetaceans. Also, detected vocalizations are compared to the number, location, and behavior of simultaneously sighted animals.
Analytic and numerical modeling of ultrasonic B-scan and echo decorrelation imaging.
Authors: Mast T. Douglas , Subramanian Swetha
Published: March 2010

An numerical model is presented for B-scan images of weakly scattering, lossy media, based on ultrasound array beam patterns calculated analytically under the Fresnel approximation. Given these beam patterns and a three-dimensional analytic or numerical tissue model, this method yields beamformed A-line signals from which B-scan images are constructed. This approach is further employed to model echo decorrelation imaging, a method for quantitatively mapping transient heat-induced changes in pulse-echo ultrasound images. In echo decorrelation imaging, a normalized decorrelation parameter is computed between A-line signals separated by milliseconds. Maps of this parameter comprise echo decorrelation images, which are potentially useful for monitoring of local tissue coagulation during thermal ablation treatments for cancer therapy. Following previous studies in which scattering cross section has been related to spatial-frequency spectra of tissue sound speed, density, and impedance variations, echo decorrelation is related quantitatively to the local decoherence of these spatial-frequency spectra. Decoherence estimates are validated by simulations employing analytic array beam patterns and random-media models for ablated tissue and are further applied to quantify tissue structure changes caused by thermal coagulation during radiofrequency ablation of ex-vivo bovine liver tissue.
Rising to the challenges of noise monitoring around construction sites.
Authors: Manvell Douglas , Alexander Martin
Published: March 2010

The construction of infrastructure and new buildings causes changes to the environment of the neighborhood both during and possibly after construction, particularly for major projects. These changes are often significant and result in concern among local population and government and often result in restrictions. To be effective and thus meet the demands on these restrictions, adequate enforcement is needed. Enforcement of noise limit compliance around construction sites needs to efficiently determine noise limit compliance, avoiding false positive exceedences, in order to provide a correct and true picture of the impact of the construction work. This paper describes some of the major challenges faced when designing, deploying, and operating a system to monitor compliance of noise regulations and limits around a construction site. It describes and compares alternative approaches to facing these challenges.
Remote construction vibration monitoring at sensitive facilities.
Authors: Newmark Marc , Zapfe Jeffrey , Wood Eric
Published: March 2010

Construction-related vibrations, while temporary, still have the potential to disrupt vibration- or noise-sensitive operations in adjacent facilities (such as hospitals, laboratories, and performing arts venues). Traditional construction vibration monitors are configured to measure levels corresponding to building damage thresholds. Unfortunately, vibration-sensitive equipment can be adversely affected at levels that are orders of magnitude lower than this. Furthermore, while most construction vibration monitors provide level information at a single dominant frequency, most criteria for sensitive equipment are specified over a range of frequencies. Generally, occupants of buildings near construction sites prefer to continue operations during the construction process. To do this, however, they need to know how the construction-related vibrations compare to their instrument criteria. To help provide this information, we have developed a remote monitoring system that provides real-time vibration and/or noise spectra in the sensitive facility. These spectra can be directly compared to instrument criteria with appropriate alarm notifications as needed. In this paper, we will present three case studies that show the evolution of this remote monitoring capability and discuss how the information has been used by the institutions where it has been installed.
Using the Federal Highway Administration Roadway Construction Noise Model for the Jerome Park reservoir construction project.
Authors: Yanez-Uribe Gabriella , Thalheimer Erich
Published: March 2010

The new Jerome Park Reservoir in the Bronx, NY, is a critical water supply source for the residents and businesses of New York city. This paper will describe the noise modeling work done in support of the project as well as an odd bug found in the FHWA’s RCNM model. Noise associated with the various construction phases and equipment for the project were analyzed to evaluate the potential loudest hour during each month of work for the project’s 50-month duration. Noise analyses were performed for expected weekday work conditions and Saturday work conditions at several receptor locations surrounding the reservoir using the FHWA’s Roadway Construction Noise Model (RCNM), Version 1.0. During the analysis, an error was found with the output function of RCNM when exporting results for multiple receptors into CSV and TXT output files. The total Leq and Lmax levels were being reported as zeros even though the correct total noise levels were displayed on screen. This error was submitted to FHWA for review, and as a result, RCNM Version 1.01 was soon released addressing the problem. More importantly, the project was performed to the client’s satisfaction and has allowed the necessary construction work to proceed.
Development of the standard ISO 7779 3rd edition: Revised and new contents.
Authors: Kimizuka Ikuo
Published: March 2010

ISO 7779 is a noise test code for airborne noise emission of information technology and telecommunications equipment (so called, ITTE). Since its 1st edition of 1988, ISO 7779 has stated, in detail, the installation and operating conditions for specific equipment categories. In nature of ITTE, however, changing of the product characteristics is much faster than the pace of standard document updates. For instance, most models of copy machines and printers (except some dedicated high speed machines) are almost being combined into new category, so called, multi-functional devices. To catch such rapid changes up timely, it becomes impractical to state specific condition within this International standard. Therefore, ISO/TC43/SC1/WG23 which is responsible for ISO 7779 decided to propose new frame work so that 3rd edition should refer to ECMA-74, annex C, which has been the industrial counterpart and also pilot standard of ISO 7779. This paper introduces background of key changes from 2nd edition and new technical contents for ITTE noise emission measurement methodologies.
Impact of personal video recorder/digital video recorder on hard disk drive acoustic requirements.
Authors: Ali Dave
Published: March 2010

In recent years the impact of the personal video recorder/digital video recorder market has grown substantially. This growth has a direct impact on the acoustic test laboratories that make sure the systems meet the manufacturer’s specification for noise emissions. To date the standards have not addressed this growth and subsequently have not provided guidance as to standardized methods of test for these systems. This paper will show the impact of the market and provide a proposed addition to the appropriate acoustic test standards.
Fan noise prediction for design.
Authors: Oppenheimer Charles
Published: March 2010

This paper develops a fan noise prediction model intended for use in the design of systems for cooling and drying. Airflow through a system is described by a dimensionless resistance parameter. Fan noise is predicted by a scaling relationship obtained from a dimensional solution of Lighthill’s acoustic analogy. The scaling relationship contains unknown proportionality factors, which are determined empirically and compared for axial fans and centrifugal blowers. The dependence of fan and blower noise spectra on non-dimensional scaling parameters is also investigated.
Improving screw compressor housing design using simulation.
Authors: Herrin D. W. , Tao Z. , Graybill A. J. , Bender J.E. , Marks P.C. , Eichelberger C.
Published: March 2010

The sound radiation from a rotary screw compressor was simulated using structural finite element and acoustic boundary element analysis. The modes of the housing were measured with and without the screws. Finite element modal analysis results were compared to the experimental modes with good agreement. Results demonstrated that the screws affected the bending modes but not the more important cylinder modes of the compressor housing. The sound radiation from the compressor housing was then predicted using acoustic boundary element analysis. The results indicated that the second and fourth pumping frequencies were close to two structural modes. Subsequent simulations investigated the effect of design changes on the housing. These changes included using a thicker cylinder and adding ribs.
Acoustics of energy efficient hand dryers: Is this progress?
Authors: Fullerton Jeffrey , Unger Gladys
Published: March 2010

Recently there have been innovations in the technology of bathroom hand dryers with a particular focus on energy efficiency. The results have included some rather interesting methods for drying wet hands in different ways than previous generations of hand dryer models. The focus of this study will be to compare the sound levels from these different energy efficient models with previous models that have been used for years. The overall sound level will be compared to the rated efficiency of each unit.
Manipulating the short time Fourier transform and cross-spectrum to estimate speech parameters.
Authors: Nelson Douglas J.
Published: March 2010

Presented are methods for automated estimation of speech parameters, including pitch, formant frequencies, and the instants of excitation of voiced speech. These methods are based on reassignment applied to the short time Fourier transform (STFT) and to the cross-spectrum computed as the product of the STFT and the complex conjugate of the STFT delayed in time. The cross-spectrum is a complex-valued surface whose magnitude is the conventional spectrogram and whose phase is the phase of the STFT differentiated with respect to time. It is demonstrated that this representation may be easily manipulated to detect and extract information, such as pitch and formant frequencies. Based on the cross-spectral representation, we present a peak representation that may be used to efficiently encode speech spectral features, and we demonstrate applications of this representation.
A characterization of scatterred acoustic intesity fields in the resonance region.
Authors: Barton Robert J. , Smith Kevin B.
Published: March 2010

In this study, we investigate the properties of the scattered acoustic vector fields generated by simple rigid and fluid-filled spheroids. Analytical solutions are derived from acoustic target strength scattering models in the near field region. Of particular interest is the understanding of the characteristics of energy flow of the scattered acoustic vector field in the near- to far-field transition region. We utilize the separable active and reactive acoustic intensity fields to investigate the structural features of the scattered field components. Numerical and in-air measured results are presented for the near and transition region scattered acoustic vector field of simple spheroids. A qualitative method is developed for characterizing submerged scatterer properties based on boundary condition and features of the scattered vector field.
Case study in cafeteria noise solutions.
Authors: Good Kenneth , Browne Sean
Published: March 2010

A recent case study was conducted addressing excessive occupant noise within a cafeteria in a Rhode Island school. A design requirement was to retain the open structure ceiling. This paper will discuss the before and after acoustic performance and the effect it had on the occupants.
The acoustical balancing act for music rehearsal spaces in schools.
Authors: Adams David L.
Published: March 2010

Conflicting acoustical criteria are encountered in the design of music rehearsal spaces, particularly when a single space must serve both orchestra and band rehearsals, not to mention the situation when the space must also serve for chorus rehearsals. For example, the criterion commonly found in the literature for room volume or more explicitly ceiling height conflicts with the requirement for an appropriate reverberation time or design goal loudness level, which are also dependent on the group (band, orchestra, and chorus) that will use the space and for that matter on the individual music teacher. The degree of involvement of music teachers in the design of these spaces and their potential impact on the end result is discussed. Case histories are presented to illustrate the good, the bad, and the ugly with respect to music rehearsal spaces in schools.
Identifying manatee location using dual-frequency sonar DIDSON.
Authors: Niezrecki Christopher
Published: March 2010

Over the last several years there has been much interest in detecting the West Indian manatee (Trichechus manatus latirostris) in turbid waters. Even in clear waters, manatees can be difficult to detect at appreciable distances by looking from above at the surface of the water. The standard DIDSON sonar is a multibeam sonar that provides dynamic images and operates at two frequencies (1.1 and 1.8 MHz). It is capable of providing high-resolution images of objects underwater that are typically scanned from the side or from above. Within this work, the DIDSON sonar is used to detect manatees at Homosassa Springs, FL. The manatees are ensonified from the side and appear to be viewed from the top. The manatees are readily apparent at a range up to 23 m for the measurements acquired in this preliminary sample. The presentation will present some of the images of manatees using a handheld diver DIDSON unit and describes some of the challenges and implications in using the device to detect manatees.