bluuebunny/crossref_metadata_2025 huggingface dataset:
Municipal Theater of Lima: Reconstruction after fire
Authors: Moy Jorge , Segami Mario , Ferrari Jose , Moscoso Richard A.
Published: October 2013

The Municipal Theater of Lima was inaugurated on 28 July 1920 as the Forero Theater and was acquired by the Metropolitan Municipality of Lima in 1929. On 2 August 1998 it was partially destroyed by fire. The damage to the audience area was minimal, allowing complete restoration. However, the stage was destroyed, which required a complete reconstruction. The Municipality of Lima launched a project competition for its reconstruction and restoration the results of which were known in 2001. One of the objectives was the correction of well-known acoustical defects, which had been never solved. The results of computer simulations of the original theater with a commercially available ray-tracing-type computer program will be presented, showing its acoustical evaluation and available options to correct the acoustical defects. The acquisition of five lots around the theater site will allow increases in the fly tower, the dressing rooms, the pit, and the shops. There are plans for the modernization of the technical and mechanical services, the accesses, the air-conditioning system, and security as well. These modifications will allow all types of presentations of contemporary arts. Retaking its position as first in the national scene, the Municipal Theater will be able to house sophisticated national and international performances.
Reuse of a cylinder shape lecture hall as a recital hall
Authors: Chiang Weihwa , Wu Weiping , Chih Wenling , Lee Choye
Published: October 2013

A cylinder shape lecture hall in Danchiang University, Taiwan was reused as a 300-seat recital hall with recording facilities. Acoustical design was analyzed with computer models and a scale model. Besides the acoustical defects due to the cylinder plan, the low ceiling height of 3.3 m caused a low reverberation with ceiling preserved but poor sound propagation with the ceiling removed because of the 1.2 deep girders. Three major convex-curved walls were used, two on both sides of the stage and the other as the partition between the hall and the control room. Two side boxes on each side of the hall were used with the box facing slightly tilted down to provide lateral reflection. Installing oval shaped supply ducts diffused the remaining concave wall surfaces. Triangular overhead panels in various sizes were used to diffuse first order ceiling reflection. Scale modeling demonstrated that most of the design strategies were not only effective in enhancing uniform energy distribution spatially but also randomized the reflection pattern for individual receivers. A low strength factor of 11 dB was beneficial for large chamber groups. On going study is conducted regarding the field tuning and measurements of the hall.
Acoustic conditioning of the metropolitan cathedral of Porto Alegre, RS, Brazil
Authors: Simoes Flavio M. , Nabinger Luciano B. , Ramalho Aline I.
Published: October 2013

In the acoustic study of the Metropolitan Cathedral of Porto Alegre, RS, Brazil, initially background noise and reverberation time were measured. A digital model was built using acoustic simulation software AcustaCadd, applying the values of the measured reverberation time. Then reverberation time, speech intelligibility, and geometric acoustics were analyzed. As a result the Project of Acoustic Conditioning was developed to correct the high reverberation time, by increasing absorption with the installation of 65000 m of panels of glass wool (100 mm, 60 kg/m). Advantage was taken of existing details in the plaster to embed the panels in the walls. Also the volume of the choir and of the lateral balcony to the altar was reduced and the interior of this was covered with the same glass wool. Special care was taken to minimize alterations to the architectural characteristics of the place, because it is a construction of historical importance. The measured values of background noise were also analyzed and appropriate acoustic isolation considered. The final measure of the reverberation time showed an average reduction of 5 seconds and better speech intelligibility, long demanded by the users. [Work supported by FAIR/FUNDATEC, BR; IUCC-US, SP.]
Frequency and directional selectivity in primary auditory afferents in fishes
Authors: Fay Richard R.
Published: October 2013

Coding of frequency and particle motion directionality is described for two fishes; goldfish (a sound-pressure specialist), and oyster toadfish (a hearing generalist). The goldfish hears in a wide bandwidth (>2 kHz) and the toadfish in a narrower one (<400 Hz). Nevertheless, the mechanisms and degree of peripheral frequency analysis appear to be similar. Reverse correlation (revcor) studies of frequency filtering in the auditory nerve reveal two fundamental filter types in both species; one at low and one at higher frequencies. The details of the two filter functions are similar, and one can be transformed into the other by introducing a simple spectral tilt to one of the filters. This suggests that only one fundamental filter exists for each species, and that the second filter type may be derived from it through alterations in the mode of coupling between the hair cell cilia and restraint structures. In spite of this simple filtering, goldfish effectively analyze the frequency components in complex and simple sounds. In both species, primary afferents show directional preferences in 3-D space that correspond to the directionalities of hair cells. Frequency analysis and directional processing in fishes share many fundamental features with those of most other vertebrates.
Auditory brainstem response (ABR), a noninvasive electrophysiological method for the study of hearing ability of fishes
Authors: Yan Hong
Published: October 2013

Over the past 100+ years several methods have been used to study hearing ability of fish. Behavioral (psychophysical) methods including food reward, barrier crossing, and electrical shock conditioning are used to train fish to respond to sound. Invasive-type of electrophysiological methods include single unit and microphonics recordings. In 1996, my laboratory developed auditory brainstem response (ABR) recording technique, an electrophysiological far-field recording method, to record acoustically evoked brainstem potentials from fish. This noninvasive method overcomes the major limitations of traditional behavioral (prolonged training period; erratic behavioral response) and electrophysiological (invasive surgery) methods. The ABR recording can be achieved easily with assemblage of conventional electrophysiological devices with the aid of computer programs. Since the development of this noninvasive electrophysiological recording method, it has been widely adopted by many laboratories around the world to study fish hearing. The role of gasbladder in hearing enhancement, the ontogenetic development of hearing ability of embryo and larval fish, the impacts of noise exposure on threshold shifts, the effect of aging on hearing all have been understood with the use of ABR method. This quick pace of achievement cannot be obtained without the use of this noninvasive recording technique. [Work supported by NIH, NOHR, IMLS.]
Role of cavitation in stone fragmentation by shock wave lithotripsy
Authors: McAteer James A. , Williams James C. , Evan Andrew P. , Cleveland Robin O. , Bailey Michael R. , Crum Lawrence A.
Published: October 2013

Several strategies were used to assess the importance of cavitation in the breakage of stones by an electrohydraulic lithotripter in vitro. (1) Stones exposed to SWs at atmospheric pressure broke readily. However, stones treated at high overpressure (OP∼125 atm) sufficient to eliminate cavitation did not break into fragments even with twice the number of SWs. Stones at OP did, however, develop transverse fractures typical of spall. This suggests that cavitation contributes to stone fragmentation, but is clearly not the only mechanism involved in stone breakage. (2) Cylindrical model stones positioned vertically in the acoustic field of a research-EHL showed proximal erosion and spall. However, placement of a mylar disk against the flat leading face of the stone eliminated cavitation-erosion, and spall did not occur. This suggests that cavitation may contribute to stone fracture by spall. (3) Time reversal of the lithotripter wave form using a pressure release reflector (Prel) also prevented stone fragmentation. With the Prel insert the tensile phase of the SW preceding the compressive wave bubble growth is interrupted by P+ and, thus, cavitation is suppressed. Together, these results suggest that cavitation plays an important role in the breakage of stones by lithotripter shock waves. [Work supported by NIH P01-DK43881.]
Overpressure and noise due to multiple airbag systems in a passenger car
Authors: Hickling Robert , Henning Peter J. , Newton Gary
Published: October 2013

Multiple airbag systems in passenger cars can generate overpressure and noise that may be hazardous to human hearing. Overpressure is compression of the air inside a closed compartment caused by deployment of the bags. Noise results from the action of the gas inflating the bags. SAE J247 provides a standard for measuring the combination of overpressure and noise in a passenger compartment. A special microphone has recently been developed that meets this standard, which operates down to a fraction of a hertz. Details of the microphone are given. Little appears to have been published on the overpressure and noise of modern multiple airbag systems, but early results [R. Hickling, ‘‘The noise of the automotive safety air cushion,’’ Noise Control Eng., May–June, 110–121 (1976)] provide a basic understanding of the phenomenon. Spectral data shows that peak overpressure occurs at about 2 to 3 Hz. A significant reduction in overpressure and noise can be achieved with an aspirating airbag, originally developed at General Motors, whose outer structure is inflated with gas from the inflator, and whose inner structure draws in air from the passenger compartment through one-way cloth valves. Tests have shown that such bags function well when impacted.
Coda wave interferometry, a new method for monitoring change
Authors: Snieder Roel , Gret Alexandre , Douma Huub , Scales John
Published: October 2013

Multiply scattered waves are extremely sensitive to small changes of the medium through which these waves have propagated. Coda Wave Interferometry [Science 295, 2253–2255 (2002)] is a new technique that utilizes multiply scattered waves in the time domain to monitor small changes in media. This is applied to ultrasonic waves that were recorded in a granite sample that was subjected to a change in temperature. Velocity perturbations of about 0.1% can be detected with this technique with an accuracy of about 0.02%. A multiply scattered wave in an elastic medium has traveled part of its trajectory as a P-wave and part as an S-wave. A model for the equilibration of P- and S-waves is presented. This model is used to extend the theory of coda wave interferometry to include elastic wave propagation. [Work was partially supported by the NSF (EAR-0106668 and EAR-0111804), by the U.S. Army Research Office (DAAG55-98-1-0070), and by the sponsors of the Consortium Project on Seismic Inverse Methods for Complex Structures at the Center for Wave Phenomena.]
Turbulent boundary layer induced vibration up to high frequencies by means of local energy methods
Authors: Hardy Pierre , Jezequel Louis , Ichchou Mohammed , Jacques Yves
Published: October 2013

The local energy method developed in the last years revealed appropriate in medium and high frequencies and supplies an accurate description of the spread of vibration and acoustic fields up to high frequencies. Our aim in the paper is to provide a complete description of the turbulent boundary layer (TBL) induced vibration by means of this method, for a simply supported thin plate. The first step in the energy method proof is the characterization of energy input from a given model of the TBL pressure interspectrum. Then, is deduced the uncoherent structural response of the panel, and the uncoherent normal mean square velocity. The latter provides, using the acoustic radiation resistance, a prediction of noise radiating by the panel up to high frequencies. Accuracy of the local energy analysis versus the usual random normal modes decomposition is demonstrated. Ultimately, a numerical parametric survey is given for various internal loss level. Precisely, the link between results provided here and SEA predictions of TBL structural induced vibration is discussed.
Fast on-line speaker/environment adaptation using modified maximum likelihood stochastic matching
Authors: Kadambe Shubha L. , Iseli Marcus
Published: October 2013

The problem of speaker/environment adaptation to improve the recognition accuracy and thus making recognizers robust is addressed here. For this, a fast on-line adaptation algorithm that does not need a separate adaptation training data and that adapts acoustic models fast enough to achieve near real-time recognition is developed. This technique is based on stochastic matching in the model space similar to [A. Shankar and C.-H. Lee, IEEE Trans. Signal Process. 4, 190–202 (1996)]. For fast adaptation only the models and the mixture components that need to be adapted are selected based on the cluster formation and Euclidean distance. This adaptation algorithm is implemented as part of a GMM based continuous speech recognizer. It is tested using a non-native speakers dataset. For example, the five best hypotheses output of the speech recognizer before and after applying the adaptation technique indicated that the right answer corresponding to an utterance ‘‘none of the earth’’ before adaptation did not correspond to the best hypothesis; however, it corresponded to the third best. After adaptation all of the five-best hypotheses converged to the right answer. The test results of this technique on a larger non-native speakers’ dataset shows 70% to 75% relative WER improvement.
Adaptive beamformer based on average vowels/consonant spectrum weights for noisy speech recognition
Authors: Nakayama Masato , Nishiura Takanobu , Kawahara Hideki
Published: October 2013

Background noise and reverberations seriously degrades the sound capture quality. A microphone-array is an ideal candidate for capturing distant-talking speech. With a microphone array, a desired speech signal can be acquired selectively by steering the directivity. The AMNOR (Adaptive Microphone-Array for Noise Reduction) is an adaptive beamformer proposed by Kaneda et al. In addition, as the beamformer for speech capture, S-AMNOR, the AMNOR with a long time speech spectrum was also proposed by Okada et al. However, the performance of the S-AMNOR may be further improved, if each adaptive filter for vowel and consonants could be designed with average vowels/consonants spectrum. Therefore, we propose the new AMNOR with adaptive filters for vowels/consonants, in order to improve the signal capturing performance. We evaluated the ASR (Automatic Speech Recognition) performance with the enhanced desired signal using the adaptive filters for vowels/consonants after detecting vowels and consonants on each phoneme. As a result of evaluation experiments, by comparing the results from the proposed AMNOR and the conventional AMNOR/S-AMNOR, we could confirm that the ASR performance was improved with proposed AMNOR. [Work supported by JSPS.]
An evaluation of talker localization based on direction of arrival estimation and statistical sound source identification
Authors: Nishiura Takanobu , Nakamura Satoshi
Published: October 2013

It is very important to capture distant-talking speech for a hands-free speech interface with high quality. A microphone array is an ideal candidate for this purpose. However, this approach requires localizing the target talker. Conventional talker localization algorithms in multiple sound source environments not only have difficulty localizing the multiple sound sources accurately, but also have difficulty localizing the target talker among known multiple sound source positions. To cope with these problems, we propose a new talker localization algorithm consisting of two algorithms. One is DOA (direction of arrival) estimation algorithm for multiple sound source localization based on CSP (cross-power spectrum phase) coefficient addition method. The other is statistical sound source identification algorithm based on GMM (Gaussian mixture model) for localizing the target talker position among localized multiple sound sources. In this paper, we particularly focus on the talker localization performance based on the combination of these two algorithms with a microphone array. We conducted evaluation experiments in real noisy reverberant environments. As a result, we confirmed that multiple sound signals can be identified accurately between ‘‘speech’’ or ‘‘non-speech’’ by the proposed algorithm. [Work supported by ATR, and MEXT of Japan.]
Audible and visual representations of the signals from a seismic landmine detection system
Authors: Scott Waymond R. , Larson Gregg D. , Martin James S.
Published: October 2013

A system using high frequency seismic waves to detect buried landmines is being investigated using both experimental and numerical models. The simplest detection cue for the localization of buried landmines has been found to be resonances of the trigger mechanism and overlying soil as these resonances create substantial localized surface displacements over the buried landmine in comparison to other buried objects such as rocks, sticks, and manmade clutter. The prototype system utilizes a noncontact radar sensor to detect surface–normal displacements and a remotely-located surface-contacting source to generate seismic waves in the ground. Processing of the measured data shows the location of mines both graphically and audibly, either of which could be used as inputs for automatic target recognition algorithms. Visual images created by a wavenumber-domain signal processing algorithm and audible representations will be compared for landmines and typical clutter objects. [Work supported by ONR and ARO.]
Ocean acoustic laboratory at the Pacific Missile Range Facility
Authors: Stein Peter , Rudzinsky Jason , Rajan Subramaniam , Lewis James
Published: October 2013

An ocean acoustic laboratory (OAL) is being implemented at the Pacific Missile Range Facility (PMRF). The range covers 1100 sq nm off the west coast of Kauai, HI, with water depths ranging from very shallow to abyssal plane. There are 172 bottom-mounted hydrophones and 15 bottom-mounted sources permanently cabled to shore. The range is used extensively for training and test and evaluation. The general OAL concept is to improve the range products by providing an accurate depiction of the four-dimensional ocean environment. A high-resolution ocean model has been implemented for the region with 48-h forecasts available on the Scientific Solutions web site (www.scisol.com/hawaii). We are currently implementing a tomographic imaging capability using the bottom-mounted sources and receivers. These sound-speed images will be assimilated into the ocean model to improve accuracy. The long-term goals include providing a real-time picture of this well-described ocean environment over the global network. Applications of the ocean acoustic laboratory include oceanographic research, ocean acoustic research, system evaluation, training, and virtual war fighting. [Work supported by ONR and CEROS.]
Use of the internet in maintaining and operating the Intermediate Scale Measurement System (ISMS) underwater test facility
Authors: Nightingale Duane , Troxel Steve , Libby Bruce
Published: October 2013

The Intermediate Scale Measurement System (ISMS) is the Navy’s premier underwater measurement facility for performing target strength and structural acoustic evaluations on 1/4 scale submarine models. Located in Bayview, Idaho, ISMS reaches out to its customers through extensive use of the internet and open source technologies. Central to the operation of the system is an apache web server used to monitor and control systems within the models and the land-based facilities. Many aspects of ISMS, including data acquisition can be performed remotely over the internet. Specific topics include overcoming firewall issues, remote monitoring and control, collaborative test development and execution, and open source tools.
A resonant scattering formalism for a fluid loaded elastic spherical near a planar boundary
Authors: Bishop Garner
Published: October 2013

Free field scattering from stationary fluid loaded elastic targets is well known and understood in terms of free field resonant scattering theory (RST), that it is given by the superposition of resonant and background components, and that the resonant components can be isolated by subtraction of an appropriate background. Backgrounds for isolating free field resonance spectra are well known. However, RST for scattering from a fluid loaded elastic target near a planar boundary where target scattering is accompanied by target-boundary scattering is less well known. A T-matrix formalism for plane wave scattering from rigid and soft spheres near a planar penetrable boundary is generalized to include a fluid loaded elastic spherical shell and RST is used to replace the free field T-matrix for the elastic shell that occurs within the formalism. It is shown that target-boundary scattering couples resonant and background components, couples modal resonances, and produces super-resonances. A background is introduced and it is shown that while background scattering is suppressed, coupled background and resonant scattering is not. Numerical results demonstrate some of the effects of target boundary scattering on the free field resonant spectrum of the shell as well as the dependence of target-boundary scattering on target.
Is the Speech Transmission Index (STI) a robust measure of sound system speech intelligibility performance?
Authors: Mapp Peter
Published: October 2013

Although RaSTI is a good indicator of the speech intelligibility capability of auditoria and similar spaces, during the past 2–3 years it has been shown that RaSTI is not a robust predictor of sound system intelligibility performance. Instead, it is now recommended, within both national and international codes and standards, that full STI measurement and analysis be employed. However, new research is reported, that indicates that STI is not as flawless, nor robust as many believe. The paper highlights a number of potential error mechanisms. It is shown that the measurement technique and signal excitation stimulus can have a significant effect on the overall result and accuracy, particularly where DSP-based equipment is employed. It is also shown that in its current state of development, STI is not capable of appropriately accounting for a number of fundamental speech and system attributes, including typical sound system frequency response variations and anomalies. This is particularly shown to be the case when a system is operating under reverberant conditions. Comparisons between actual system measurements and corresponding word score data are reported where errors of up to 50 implications for VA and PA system performance verification will be discussed.
General considerations regarding the importance of a study of the acoustic conditions of churches with historic and artistic value in Mexico. The case of baroque architecture
Authors: Rodriguez Manzo Fausto , Kotasek Gonzalez Eduardo
Published: October 2013

This paper deals with the problem of old churches in Mexico with historic and artistic value. Some churches in the baroque period in Mexico are examples of a kind of building used as concert and conference halls. However there is a lack of acoustic knowledge of these kinds of architectural spaces in Mexico. This knowledge will also augment that of the historic, artistic and architectural point of view, and be a foundation for high-quality renovation and preservation projects for this type of building. The particular characteristics of some of the most significant churches of this period are presented as well as a first architectural acoustics review of them.
Features of echoes bottlenose dolphins use to perceive object properties
Authors: DeLong Caroline M. , Au Whitlow W. L. , Harley Heidi E.
Published: October 2013

Echolocating bottlenose dolphins can discriminate among objects that vary in size, shape, and structure. Our purpose in this project is to investigate the features of echoes dolphins may use to determine each of these object properties (e.g., target strength, number, and position of highlights). A dolphin performed a cross-modal matching task where he was presented with an object in one modality (e.g., vision) and then asked to choose the same object from among a group of three objects using another modality (e.g., echolocation). The dolphin was presented with object sets in which the objects within the set varied along one feature (size or shape or material or texture). These objects were later ensonified with dolphin-like clicks and the object echoes were collected with a binaural (two hydrophone) system. To mimic the dolphin’s ability to scan across objects, echoes were captured as the objects were rotated. Differences in echoic features within object sets were examined along with the dolphin’s error. In addition, an artificial neural network (ANN) was used to classify objects using the object echoes. The ANN was utilized to explore the importance of spectral versus time domain features, and single versus multiple object orientations in object classification.
Hearing is an active process in mosquitoes
Authors: Robert Daniel , Goepfert Martin C.
Published: October 2013

Auditory sensitivity and frequency selectivity are enhanced by active mechanics. Known from vertebrates, active audition is established for an invertebrate. The auditory mechanics of antennal sound receivers in mosquitoes exhibits key diagnostic features of active mechanics: (a) physiologically vulnerable sensitivity and tuning. The mechanical sensitivity and tuning sharpness of the receiver decrease after death. (b) Vulnerable nonlinear mechanical response. Nonlinearity is expressed as amplitude-dependent damping: lower stimulus intensities result in larger response gain and sharper resonance peaks. This band-limited nonlinearity disappears post-mortem. (c) Hypoxia sensitivity. In females, transient exposure to CO2 reversibly reduces tuning sharpness. In males, the effect is opposite: CO2 sharpens tuning and elicits large vibrations in the absence of acoustic stimulation. Hypoxia-induced vibrations are unrelated to external forces; they are autonomous and self-sustained, and forcibly generated by an internal motor. (d) Autonomous antennal vibration (AV). AV is also induced by the injection of dimethylsufoxide (DMSO). DMSO-induced AV persists (90 min) at large amplitudes (>400 nm). Antennal deflection shapes rule out the involvement of muscles, narrowing down the source of mechanical activity to the auditory sense organ at the antennas base. [Work supported by the Leopoldina Academic Society, the Swiss National Science Foundation, BBSRC and the University of Bristol.]
Micromechanics of Drosophila audition
Authors: Goepfert Martin C. , Robert Daniel
Published: October 2013

In Drosophila melanogaster, hearing is mediated by the antenna, vibrations of which are transduced by Johnston’s organ. The receiver’s mechanical response exhibits key features of active mechanics. Limit cycle oscillations (LCO) can be measured in untreated animals and after the injection of dimethylsulphoxide. LCO are entrained by acoustic stimuli and reversibly vanish during hypoxia. The mechanical response is nonlinear, exhibiting an increase in resonance frequency with stimulus intensity. This nonlinear stiffness is reversibly affected by hypoxia and disappears post mortem. The origin of mechanical nonlinearity and LCO was traced in auditory mutants no-mechanoreceptor-potential A. NompA protein links the receptor neurone dendrites to the extracellular caps. Mutations in the nompA gene thus mechanically isolate the auditory receptors from antennal structures, resulting in conductive hearing loss. An antennal response in nompA flies lacks LCO and the nonlinear stiffness alteration of controls. Also, LCO and intensity-dependent stiffness depend on functional mechanotransduction channels: mutations in nompC linearize antennal mechanics. Similar effects are measured in touch-insensitive-larva B (tilB) and beethoven (btv) mutants, indicating that mechanical activity in Drosophila ensues from the interplay between nompC channels and receptor cilia, possibly involving ciliary motility. [Work supported by the Leopoldina Academic Society, the Swiss Science Foundation, BBSRC, and the University of Bristol.]
Transdermal drug delivery by sono-macroporation
Authors: Weimann Ludwig , Wu Junru
Published: October 2013

A feasibility study of using high amplitude ultrasound to deliver large molecules transdermally was undertaken. Ultrasound (20 kHz) of intensity in the range between 2 to 50 W/cm2 was used to increase the permeability of skin in vitro to poly-l-lysines as models of drug molecules. When 20 kHz, 5% duty cycle ultrasound at the spatial average and pulse average intensity ISAPA=19 W/cm2 was applied for 10 min the skin permeability was calculated to be 0.5±0.2 cm/h and 8.5±4.2 cm/h, respectively, for poly-l-lysine-FITC (51 kDa) and octa-l-lysine-FITC (2.5 kDa). Without application of ultrasound the skin permeability of the above-mentioned molecules was essentially zero. A transdermal flux enhancement occurred during the process reported here was much higher than that due to sonophoresis (ISAPA<2 W/cm2) as reported in literature (Mitragotri et al., 1995). Reported here are experimental results from transdermal flux kinetis, and confocal microscopic cross sectional and optical images suggest the formation of pores in the stratum corneum whose size varies with skin samples and may be in the range of 1–100 μm. The confocal images also suggest the formation of micron-size pathways in epidermis during ultrasound exposure.
Sound power measurement standards at laboratory and field environments
Authors: Taibo Lucìa , Riganti Jorge , Dittmar Waldemar
Published: October 2013

Sound power level measurements, SWLs, of equipment and machinery through direct or comparison methods at laboratory or field conditions, are of increasing importance in terms of regulations and industrial competitiveness. SWLs constitute the input data when modeling the real world, in complex industrial premises for example, as a means for diagnosis and SPL predictions. SWLs have a major technical and economical impact, trying to keep the measurement uncertainties as low as possible, while balancing the testing complexity, time consumption, and costs. In the present work, a description about the calibration of a Reference Sound Source, RSS, B&K 4204 [ISO 6926] is made. The testing survey of normal equipment emitting steady noise and the RSS at different acoustical environments, that range from an hemi-anechoic room to a typical industrial facility is also described. Some measuring methods such as ISO 3745, ISO 3744, ISO 9614-2 are compared for the different sources and environments, yielding some discrepancies between standards as is extensively referred to in literature. A proposal based on a new multiple height microphone array is encouraged at laboratory conditions. Regarding field tests, sound intensity measurements by scanning is extensively adopted for practical reasons, with acceptable results according to our experience.
A BIPM/CIPM key comparison covering the calibration of ultrasonic hydrophones over the frequency range 1 MHz to 15 MHz
Authors: Zeqiri Bajram , Lee Nigel D.
Published: October 2013

A central objective of the Mutual Recognition Arrangement (MRA), signed by national measurement institute (NMI) directors in 1999, is the establishment of the degrees of equivalence of national measurement standards held by each institute. International comparisons, known as key comparisons, represent the sole mechanism for establishing these degrees of equivalence. In this paper we describe a key comparison, undertaken under the auspices of the BIPM/CIPM Consultative Committee for Acoustics, Ultrasound, and Vibration, related to the realization of the acoustic pascal in water at ultrasonic frequencies. This is most appropriately achieved through a comparison of calibrations of stable transfer standard hydrophones; 1 mm active element bilaminar membrane hydrophones, being chosen for this purpose. With NPL acting as the pilot laboratory, two hydrophones were calibrated using the NPL primary standard laser interferometer and circulated sequentially to participant NMI laboratories in Germany, China, The Netherlands, and Denmark. Laboratories were asked to report values for the hydrophone open-circuit free-field sensitivity over the frequency range 1 MHz to 15 MHz. The principal calibration methods used by the NMIs were optical interferometry and/or two-transducer reciprocity. The key comparison process, its results, and the analysis used to derive the key comparison reference values, are all described in detail.
Concerthalls.org: A webpage for architectural acoustics education
Authors: Wang Lily M. , Hall Jessica M.
Published: October 2013

A website focusing on concert hall acoustics (www.concerthalls.org) has been developed under the Schultz Grant from the Newman Student Award Fund. The website includes historical information, discussions on a variety of architectural acoustical measures, links to other websites of interest including a collection of concert hall webpages, and a comprehensive reference list. Of particular interest are the many listening examples provided on the website, which help students and other visitors to understand each subjective quality audibly and give insight on how to measure and control the associated objective measure. Examples are provided for reverberation, clarity, intimacy, warmth, loudness, and spaciousness. Various samples will be played during this presentation. Instructors of architectural acoustics are encouraged to introduce the site to their students and incorporate it into their instructional materials. [Work supported by Schultz Grant from the Newman Student Award Fund.]
Physical models of the human vocal tract as tools for education in acoustics
Authors: Arai Takayuki , Maeda Eri , Saika Noriko , Murahara Yuji
Published: October 2013

We recently replicated the Chiba and Kajiyama physical models of the human vocal tract and found that they are extremely effective as a manipulative tool for education in acoustics. This study is an overview of our previous development of the models and their application for education. The models we developed simulate the configuration of the vocal tract, and are of two major types: cylinder and plate. The interior, bottle shape of the cylindrical models was based on the original measurements of Chiba and Kajiyama. The diameters of the holes in the 10–17 movable plates of the plate-type model were also based on the Chiba and Kajiyama measurements, but the radius curves were approximated at 10 mm resolution in a stepwise fashion. We also developed a nasalized model, which consists of a side branch attaching to a cylindrical model. Our experience confirmed that when used in a classroom environment, the models increase student understanding of the acoustic theory of speech production.
Application of statistical energy analysis to the design of crew rest compartments
Authors: Gmerek Mark M.
Published: October 2013

Longer flight times for modern commercial aircraft have led to the need for crew rest compartments. Noise levels in the crew rest compartments must be conducive to proper rest and recuperation. Statistical Energy Analysis (SEA) has been used to develop a 777 crew rest compartment design that achieves appropriate noise levels at acceptable weight and cost. In this paper the design of a 777 overhead crew rest compartment is outlined using SEA design tools and methods. Noise data were gathered in flight to distinguish airplane source components and develop model inputs. Crew rest panels, the airplane fuselage, and acoustic volumes were modeled as SEA subsystems by taking into account geometry, material properties, modulus, and damping. A model was built, excited with inputs, and analyzed to determine energy flow paths and acoustic pressure at receiver locations. Prospective add-on treatments were then assessed to engineer an effective noise control package. The model development was supplemented by laboratory sound transmission loss testing of individual components. The good agreement between the laboratory tests and individual SEA models of the components increased confidence in the approach. Once the crew rest was installed on the airplane, the measured in-flight noise levels closely matched the SEA estimates.
Rayleigh scattering and heterodyne detection as a nonintrusive microphone
Authors: Aguilar Cesar , Azpeitia Carlos , Porta Andres , Stern Catalina
Published: October 2013

Heterodyne detection of a monochromatic laser beam scattered by molecules in a transparent gas gives a signal that is proportional to the spatial Fourier transform of density fluctuations for a wave vector determined by the optics. In a turbulent air jet, density fluctuations are due to either acoustic waves or to entropy fluctuations. This technique captures both. The method can then be used as a nonintrusive microphone to study the propagation of acoustic waves inside the jet. At each point in the flow the direction of propagation of the acoustic wave is determined, and the acoustic field can be described. This will eventually help to localize the sources of the waves in the flow and hopefully determine the hydrodynamic event that generates these waves.
Monitoring of atmospheric nuclear explosions with infrasonic microphone arrays
Authors: Wilson Charles R.
Published: October 2013

A review is given of the various United States programs for the infrasonic monitoring of atmospheric nuclear explosions from their inception in 1946 to their termination in 1975. The US Atomic Energy Detection System (USAEDS) monitored all nuclear weapons tests that were conducted by the Soviet Union, France, China, and the US with arrays of sensitive microbarographs in a worldwide network of infrasonic stations. A discussion of the source mechanism for the creation and subsequent propagation around the globe of long wavelength infrasound from explosions (volcanic and nuclear) is given to show the efficacy of infrasonic monitoring for the detection of atmospheric nuclear weapons tests. The equipment that was used for infrasound detection, the design of the sensor arrays, and the data processing techniques that were used by USAEDS are all discussed.
Reconstructing acoustic radiation using eigenfunction expansions
Authors: Maynard J. D.
Published: October 2013

A powerful tool for reconstructing the sound radiation from a vibrating structure is near-field acoustic holography. In this method, the sound pressure is measured at points near the vibrating structure, and these data are analyzed by computer to determine any desired feature of the entire sound field, including acoustic energy sources at the vibrating structure. Some versions of this method have involved first solving the ‘‘forward problem,’’ which consists of finding the radiated sound field, assuming that the surface velocity of the vibrating structure is known. Usually such problems are solved using acoustic boundary elements. However, we have been studying a method for solving the reconstruction problem and by-passing the forward problem by using eigenfunction expansions. Furthermore, Sean Wu has developed a significant extension of the technique for solving the forward problem, and this method may challenge the boundary element method. In this talk, the fundamentals of the eigenfunction expansion method will be reviewed, and results of some practical tests will be presented.
Nearfield acoustic holography and its evolution
Authors: Wu Sean
Published: October 2013

This paper reviews the evolution of nearfield acoustic holography (NAH) over the past two decades. The original NAH (Williams and Maynard, 1980) could only reconstruct acoustic radiation from a surface containing a level of constant coordinate in an exterior region. Soon a generalized NAH based on the Helmholtz integral theory and boundary element method (BEM) was developed to reconstruct acoustic radiation from arbitrarily shaped surfaces. This BEM-based NAH is advantageous in many aspects, but has several inherent shortcomings. An alternative is to expand the acoustic field in terms of the spherical wave functions, the most prominent one being the Helmholtz equation–least squares (HELS) method. This HELS method offers a great flexibility and versatility in reconstructing the acoustic fields in both exterior and interior regions, and allows reconstruction of transient acoustic radiation from impulsively accelerated objects. Meanwhile, we have seen the extension of NAH to characterize acoustic sources of a moving object and variations of NAH based on measurements of acoustic intensity rather than pressures. Many techniques are developed along the way to tackle the ill-posedness difficulties inherent in this inverse acoustic problem. Progression of able researchers is transforming NAH into an ever more powerful diagnostic tool. [Work supported by NSF.]
Acoustic imaging of harmonic near-field sources from surface pressure measurements on a body using singular value decomposition
Authors: Stepanishen Peter R. , Brodjonegoro Irsan
Published: October 2013

An inverse or backward projection method based on a combined Greens function and singular value decomposition method is developed to locate and to determine the strength of near field harmonic sources from the acoustic field on the surface of a nearby rigid body. A resolution matrix, which is based on the free space Greens function, the geometry of the measurement surface of interest and the field locations of interest, is introduced to determine the resolution and accuracy of the backward projection method. Point source distributions located above a rigid planar surface are addressed both analytically and numerically. In addition, line source distributions located outside of infinite rigid circular and elliptical cylinders are also addressed. It is demonstrated that the method is able to identify the location and to determine the strength of harmonic near-field sources which are separated by less than 0.01 of a wavelength.
Examination of the relevance of cochlear dead regions to hearing aid fittings
Authors: Dybala Paul D. , Thibodeau Linda M.
Published: October 2013

Vickers et al. [J. Acoust. Soc. Am. 110, 1164–1175 (2001)] suggested that identification of Cochlear Dead Regions (CoDR) may provide information relative to hearing aid fittings. The relationship between CoDR and hearing aid fittings was explored in the current study two ways: (1) by reviewing the hearing loss characteristics of Vickers et al. (2001) subjects with CoDR using the Articulation Index, and (2) examining the frequency of CoDR in a clinical population. Using amplified, low-pass filtered nonsense syllables Vickers et al. (2001) found a relationship between the edge of the identified high-frequency CoDR and the filter setting that provided optimal syllable recognition. Because of the severity of the high-frequency hearing loss for the CoDR group the Articulation Index results from the present study suggested that these listeners may have not benefited from high-frequency amplification because of inaudibility. The frequency of CoDR was determined in a clinical population using the Threshold Equalization Noise (TEN) test described in Moore et al. [Br. J. Audiol. 34, 205–224 (2000)]. Results suggested that CoDR are not encountered as frequently as implied in the literature. These findings have important implications on how CoDR testing relates to hearing aid fittings.
Application of Plomp’s model to recognition of the Hearing in Noise Test sentences
Authors: Thibodeau Linda M. , Scott Jack M.
Published: October 2013

Sensitive measures of speech recognition are needed for adequate characterization of the effects of various types and degrees of hearing loss. The Hearing in Noise Test (HINT), by Nilsson et al. [J. Acoust. Soc. Am. 95, 1085–1099 (1994)], was developed to quantify the benefits of binaural amplification by measuring a reception threshold for sentences (RTS) in the soundfield in quiet and various noise arrangements. The purpose of the present study was to expand the use of the HINT as a tool to characterize effects of hearing loss in monotic listening conditions. Modeled after Plomp’s [J. Acoust. Soc. Am. 63, 533–549 (1978)] adaptive, speech-recognition paradigm with Dutch sentences, the HINT sentences were presented in quiet and in increasing noise levels via insert receivers to listeners with normal and mild-to-severe hearing impairments. Following Plomp’s analysis, two variables were derived for each listener with hearing loss from the function relating RTS to noise level: A and D, which represent attenuation and distortion effects, respectively. As expected, the pure-tone average was more strongly correlated with A than with D. Derivation of these two variables was also explored using an abbreviated procedure of only two RTS values, one in quiet and one in noise.
Auditory-visual integration: A comparison of neuropathy and developmental dyslexia
Authors: Ramirez Joshua C. , Mann Virginia
Published: October 2013

Auditory neuropathy and developmental dyslexia have been previously associated with inferior perception of acoustic speech in noise. To probe the underlying mechanisms of these deficits, an audio-visual integration experiment was conducted to compare the speech perception abilities of reading-impaired subjects and auditory neuropathy patients (relative to controls). Natural acoustic speech stimuli that were white-noise masked at various intensities and accompanied by a video of the talker were presented to subjects. Neuropathy patients were expected to benefit from the pairing of visually presented articulatory cues and auditory CV stimuli, owing to the fact that their speech perception impairment reflects a peripheral auditory disorder. To the extent that developmental dyslexia reflects a general impairment of speech processing rather than a peripheral disorder of audition, it was hypothesized that reading-impaired subjects would not benefit from an introduction of visual cues. Current experimental data yielded a significant correlation between reading ability and dependence upon visual cues. Furthermore, under conditions where articulatory cues are matched with heavily masked CV stimuli, neuropathy patients and controls made more use of the visual cues than reading-impaired subjects. This may suggest that some forms of reading impairment stem from deficits of general speeach processing.