bluuebunny/crossref_metadata_2025 huggingface dataset:
Voice quality of emphatics in comparison with non-emphatics in Morrocan Arabic
Authors: Shoul Karim
Published: May 2008

Based on acoustic and physiological data, this study examines the voice quality of emphacized (also called pharyngealized) vowels in Moroccan Arabic. The aim is to determine whether, as argued by some authors (Heath 1987, Fre woldu 1986), these vowels are creaky or glottalized. For this purpose, the /a/ vowel is considred in syllables after initial and intervocalic /t, d, s/ and their emphatic counterparts for an acoustic study as well as a physiological one (Fourcin's EGG 1974). The cues axamined inculde F0 values, duration and amplitude of the acoustic and glottalic signals, as well as the open quotien (0q) (as seen by Henrich 2001). Results of the acoustic analysis show no significant differences between emphacized and non-emphacized vowels as far as F0 values, duration and amplitude of the acoustic signal are concerned. The same absence of difference is observed from the EGG experiment, which indicate that 0q represents half of the whole glottal phase. These findings sugget that emphacized vowels, just like the corresponding non-emphacized counterparts, are characterized by a modal voice quality. They imply that 'secondary' pharyngealization does not require a narrowing of the supra-glottic cavity which would affect the mode of vocal-fold vibrations.
Influence of multi-channel dynamic range compression on intelligibility: effect of envelope modulation bandwidth
Authors: Stone Michael A. , Füllgrabe Christian , Moore Brian
Published: May 2008

Stone and Moore [J. Acoust. Soc. Am. (in press)] showed that, as the speed and number of channels in a multi-channel compressor increased, intelligibility of noise-vocoded signals in a competing speech task decreased. The noise vocoder is often used to simulate the information conveyed by cochlear implants. However, the vocoder of Stone and Moore preserved only low-rate (<45 Hz) envelope modulations whereas some implantees show sensitivity to envelope modulation rates up to about 300 Hz. Furthermore, intrinsic fluctuations in the noise carriers affect the reception of low-rate modulations of the signal (Whitmal et al. [J. Acoust. Soc. Am. 122:2376-2388, (2007)]). Here, a tone vocoder with N=8 or N=16 channels was used. Vocoding was preceded by N/8, N/4, or N/2 channels of compression, each using one of three speeds, affecting modulation rates up to about 2, 6, or 18 Hz, respectively. The lowpass filters extracting the channel envelopes had corner frequencies of 45 or 180 Hz. Intelligibility was measured using IEEE sentences with a competing speaker. The deleterious effect of compression with increasing channel number and speed was greater for the lower corner frequency. Compression of rates below 6 Hz affected intelligibility, independent of the presence of higher modulation rates.
Training-induced auditory plasticity measured using auditory steady-state responses
Authors: Kluk Karolina , Tan Christine M. , John Michael S. , Picton Terence W.
Published: May 2008

Re-mapping of the primary auditory cortex may be induced by extensive training. For example, training of monkeys to perform frequency discrimination (FD) at one carrier frequency expands the representation of that frequency region in the auditory cortex. This study was intended to demonstrate training-induced auditory plasticity using auditory steady-state responses (ASSRs) in humans. Right-handed, non-musicians underwent FD training in their left ear only at 1 kHz. ASSRs were recorded to 1- and 2-kHz amplitude modulated tones (100 % AM depth at rates of 41, 83 and 45, 87 Hz, across two conditions). ASSRs recorded at the start of the experiment were compared with the ASSRs recorded after three two-hour sessions of FD training scheduled 24 hours apart. The results revealed significant increase in the amplitude of ASSRs recorded to 41- and 45-Hz AM tones (at 1 kHz only) presented to the trained left ear. There was no significant change in the amplitude of ASSRs recorded to the 2-kHz tones or to any stimuli presented to the un-trained right ear. As expected FD training had no effect on 83- and 87-Hz ASSRs (which are generated mainly in the brainstem). These results support the idea of training-induced reorganization of the auditory cortex.
Form and content in emotional reactions to sounds
Authors: Vastfjall Daniel , Asutay Erkin , Genell Anders , Tajadura Ana
Published: May 2008

People react emotionally to auditory stimuli. Despite this fact relatively little is known how sounds can create emotional reactions in listeners. We have developed a framework, the Emotion Reaction Model (ERM), that predict that both form features (i.e classical psychophysical attributes such as loudness, sharpness etc) and content feratures (i.e. psychological associations to the sound producing source). Using ERM we tested the relative contribution of form vs. content in producing emotional reactions to sounds. In a first experiment, participants rated their emotional reactions to sounds from qualitatively different categories (animals, humans, machine noise) and to same sounds with time or frequency scrambling applied (thus rendering them difficult to identify, but with retained psychoacoustical properties). Experiments 2 used the same sounds but with a priming procedure and experiment 3 assessed emotional reactions using physiological measures. Overall, content, rather than form, appeared to have the biggest impact on emotional reactions. This research may complement traditional psychoacoustical theories that focus solely on form features.
Temporal response of a simplified bidimensional numerical model of the cochlea
Authors: Lepine Christine , Gibiat Vincent
Published: May 2008

Within the framework of a study related to bone conduction, numerical simulations have been performed in the time domain, with the aim of comparing the cochlear partition displacement in the case of different places of stimulation. An oversimplified 2D model of the cochlea is used. It is first excited with pulses centered on various audible-range frequencies with a localisation of the source which is analogous to the position of the oval window. Secondly, new sets of calculations introduce different localisations and/or spatial extensions of the sources. An analogy with seismology being adequate to simulate the solid-fluid (cochlear partition-perilymph) coupling, a finite difference numerical simulation based upon the Virieux scheme for elastic waves propagation has been used. The movement of the simplified basilar membrane is observable when excited via air or bone conduction. Results of the propagation of a single pulse within the model will be presented and discussed through information available in literature.
Hemispheric Differences in the Recognition of Environmental Sounds
Authors: Gonzalez Julio , McLennan Conor T.
Published: May 2008

In the visual domain, Marsolek and colleagues have provided support for their claim that two dissociable and parallel neural subsystems underlie abstract and specific object recognition [Marsolek, 1999; Marsolek & Burgund, 2003]. According to their dissociable subsystems theory, an abstract-category subsystem operates more effectively in the left hemisphere (LH) and is less sensitive to the specific surface characteristics of the stimuli, whereas a specific-exemplar subsystem operates more effectively in the right hemisphere (RH) and is more sensitive to specific stimulus characteristics. In the present study, we tested this hypothesis in the auditory domain by conducting 2 long-term repetition-priming experiments on the recognition of environmental sounds. Participants attempted to identify target sounds from an initial 750 ms sound stem. Target stems were primed by either an identical or a different exemplar sound (e.g., the same or different tokens of a bagpipe). Target stems were presented monaurally in both experiments; however, in Exp. 2 white noise was simultaneously administered to the opposite ear. Our results are consistent with Marsolek's framework. In particular, in both experiments an exemplar specificity effect was obtained when the sounds were presented to the left ear (RH), but not when the sounds were presented to the right ear (LH).
Perception of speech properties from extremely brief segments
Authors: Harding Sue , Cooke Martin
Published: May 2008

A glance at a visual scene enables observers to become rapidly aware of its most important characteristics. Here, we describe experiments using very brief segments of natural speech which demonstrate that a surprising amount of information can be determined from only a few milliseconds of the auditory signal. Segments with durations ranging from 2.5 to 80 ms were extracted from six vowels and six fricatives spoken by males and females. Listeners identified the phoneme and/or gender, or whether a vowel or consonant had been presented. While listeners' performance dropped close to chance for the 2.5 ms stimuli for most tasks, for the vowel/fricative distinction listeners obtained scores above 70% even for such short segments. Listeners performed well above chance for the 10 ms stimuli for three out of four tasks. Combining results within tasks showed that listeners also distinguished voiced from unvoiced phonemes in less than 10 ms. Threshold values from logistic fits indicate the order in which information becomes available: vowel/fricative distinction (3.0 ms), voicing distinction (6.7 ms), phoneme identification (11.9 ms) and gender identification (15.3 ms). By exploiting the "gist" of an auditory scene, listeners may be able to deploy prior knowledge rapidly to constrain further interpretation.
The influence of pinna position on head-related transfer function
Authors: Plaskota Przemyslaw , Dobrucki Andrzej B.
Published: May 2008

The changes of spectrum of sound at listener ear are one of the major cues for sound source localization. Head Related Transfer-Function (HRTF) describes the influence of torso, head and pinna on sound spectrum. It is possible to recognize HRTF using computational method, e.g. Boundary Elements Method (BEM). The numerical model used for calculation of HRTF is constructed by transfer geometrical shape of head and pinna into numerical domain. Important question during geometry reconstruction process is the accuracy of shape mapping. The pinna has significant influence on HRFT. In the paper, the influence of accuracy of pinna geometry transformation and pinna position on HRTF is presented. Particularly, the pinna flare angle, pinna rotation angle and position of ear entrance were taking into considerations. Measurements have been done on numerical model with the invariable pinna and head shapes, using BEM method.
Environmental Enrichment Increases Response Strength And Paired-Pulse Depression Of Auditory Cortex Neurons
Authors: Percaccio Cherie R. , Pruette Autumn L. , Mistry Shilpa T. , Chen Yeting H. , Rathbun Daniel L. , Kilgard Michael P.
Published: May 2008

A wide variety of sensory gating impairments have been associated with autism. Abnormal brain development may alter patterns of interaction between the child and the environment and hinder the acquisition of critical language skills. After several months of therapy, autistic symptoms may subside as children advance to higher cognitive stages. This study modeled the physiological changes associated with therapy-related gains in children by investigating enrichment-induced plasticity in rat auditory cortex. Evoked potential response strength and paired-pulse depression were enhanced by exposure to an enriched environment and degraded by exposure to a standard environment. While neither exercise nor social stimulation, specifically, resulted in any plasticity, rats that heard the enriched environment from a distance also exhibited enhanced responses. The degree of enrichment-induced plasticity was not reduced by a substantial and persistent cholinergic deficit. The finding that enrichment increases response strength and paired-pulse depression in the auditory cortex of rats is consistent with earlier clinical observations, suggesting that proper sensory development is necessary for higher cognitive processes. In the future we will investigate if clinical gains during and after therapy are associated with increased event-related potential discrimination and hemispheric localization of speech stimuli in children with autism.
Toward synthesis tools using 'evocation' as control parameters
Authors: Merer Adrien , Aramaki Mitsuko , Kronland-Martinet Richard , Ystad Solvi
Published: May 2008

This study addresses the design of synthesis tool controlled by high-level parameters, such as mental evocations induced by sounds. As a first approach, we considered sounds evoking motions and we addressed 3 main questions: What are the different categories of motion? What are the common acoustic features of sounds within a category? How to synthesize sounds that evokes specific motions? We gathered samples used by electro-acoustic music composers as a framework for their compositions and synthesized sounds. Then we effectuated a two-steps listening test. The first part aims at determining these different motion categories. It consisted in a free categorization task in which listeners build their own groups of sounds as function of evoked motions. The second part aims at determining a set of sounds characteristic of each of these categories. It consisted in a constrained categorization task with predefined categories represented by prototypical sounds (deduced from free categorization task). We used a feature selection method to highlight most relevant signal descriptors for each category. Finally, designing a synthesis tool implies the calibration of these descriptors (a specific range of values for each category) and their control (leading to address the inverse problem). These aspects are currently being investigated.
Adaptive predictive feedback control of circular plate vibrations
Authors: Leniowska Lucyna , Kos Pawel
Published: May 2008

Adaptive predictive controller, consists of an on-line identification technique coupled with a control scheme, is used in this paper for a plate vibration suppression. It is assumed, that the system to be regulated is unknown and the control schemes presented have the ability to identify and suppress the plate vibrations with only an initial estimate of the system order. The choice of structure is motivated by its representative nature. This configuration has also been well studied by the authors both analytically and experimentally, using several kind of controllers (PID, PI2D, fuzzy, LQR). There are two fundamental steps involved in the closed-loop system. The first step is to identify a mathematical model. The second step is to use the identified model to design a controller. One drawback of this approach is that, the control signal is fed to the actuator after updates of the control law expression, which always leads to some delay. In order to align better the updating process, the authors introduce the prediction of plant output with established error convergence. The one-step ahead system output prediction is calculated from the recursive formulas of the interpolation functions chosen. Simulations are included and discussed.
Voice production modes and vocal tract shape in South-Siberian throat-singing
Authors: Grawunder Sven
Published: May 2008

South-Siberian throat-singing features reinforced harmonics as carrier of sung melodies and enforced phonation modes. Available articulatory studies of throat-singers suggest that throat-singing makes use of three voice production mechanisms which result in two basic voice modes (mid tensed vs. low rough). Thus all three mechanisms share an excessive constriction of the larynx entrance i.e. approximation of the aryepiglottic folds and the epiglottis. The current study comprises acoustic data from 69 male singers. 25 singer were recorded by use of a field setting for acoustic, electroglottographic and subglottal resonance signal acquisition. Perturbation measures show dominance of individual variability over areal (cultural) factors, but strong influence of articulatory reinforcement strategies. The data also provide evidence for a model of reinforcement of harmonics by means of (1) voice source variation (closing phase, excitation strength), i.e. increased subglottal pressure, while air flow remains constant or lowered for the tensed mode; and double cycle modes involving mass bodies of upper laryngeal structures for the low mode; (2) formant merging due to multiple vocal tract constrictions including a coupling of source to the adjacent epilaryngeal tube of 1/6 vocal-tract length and bandwidth tuning as a result of adjustment of lip radiation.
Empirical articulatory-acoustic relations for vowels
Authors: McGowan Richard S. , Berger Michael A.
Published: May 2008

Vowels tokens were extracted from four talkers in the Wisconsin X-ray Microbeam Speech Production Database. The neighboring phonemes of these vowels were restricted to be non-nasal and non-liquid. The first three formant frequencies were measured using LPC analysis with manual corrections at a rate corresponding to the pellet trajectory sampling rate, thus yielding large amounts of simultaneous formant frequency and pellet position data points (between 11,000 and 20,000 for each talker.) Principal components analysis was performed for both the formant frequencies and the pellet position data, to produce three orthogonal acoustic components and four orthogonal articulatory components. A local linear regression technique, known as loess [Cleveland, W. S. and Devlin, S. J. (1988), J. Amer. Stat. Assoc., 83, 596 - 610], was applied to orthogonal components to map between the acoustic and articulatory domains. This technique permits regression slopes to vary within the domain of the independent variables. The results will be discussed in terms of optimization of loess parameters (e.g. size of local neighborhoods), goodness of fit of the mappings, and the degree to which slopes in the mappings vary. Manually corrected formant frequencies will be compared with fully automatic Line Spectral Frequencies. [Supported by NIDCD-001247 to CReSS LLC]
Acoustic characteristics of solid vocal tracts modeled from ATR MRI database of Japanese vowel production
Authors: Kitamura Tatsuya , Takemoto Hironori , Honda Kiyoshi
Published: May 2008

"ATR MRI database of Japanese vowel production" provides volumetric magnetic resonance images and speech data of the five Japanese vowels produced by a male native Japanese speaker. In this study, the database was used to evaluate acoustic characteristics of vocal tracts for five Japanese vowels; we measured frequency responses of realistic vocal tract solid models formed by a stereo-lithographic technique. The model's glottis was sealed with a plastic plane with a 1.2-mm hole. A time-stretched pulse signal generated from a horn driver unit was introduced into the solid model at the lip end. The response signals of the models were recorded at the model's glottis from the hole by a probe microphone. This method permits accurate measurement of acoustic characteristics of the vocal tract including the laryngeal cavity, which generates the laryngeal cavity resonance during closed-glottis periods of phonation [H. Takemoto et al., JASA, 120, 2228-2238 (2006), T. Kitamura et al., JASA, 120, 2239-2249 (2006)]. The results provide a benchmark for evaluating numerical analysis methods, such as transmission line models, finite element methods, and finite difference-time domain-methods, which have been used to study vocal tract acoustics. [Work supported by SCOPE (071705001) of Ministry of Internal Affairs and Communications, Japan.]
Effects of auditory, visual, and audio-visual training on nonnative perception of English fricatives
Authors: Wang Yue , Behne Dawn , Cooper Angela , Jiang Haisheng , Leung Nina , Tu Jung-Yueh
Published: May 2008

This study examines the effects of auditory (A), visual (V), and audio-visual (AV) training on nonnative speech perception. Mandarin Chinese natives were trained to perceive English voiceless fricatives (in monosyllabic words and nonwords) of three visually distinct places of articulation: interdentals nonexistent in Mandarin, labiodentals and alveolars common in both languages. Participants were randomly assigned to a control group or one of three 2-week (six sessions, 40 minutes/session) training groups with a different input modality: A, V, or AV. In pre- and post-tests, the fricatives are presented in four ways for an identification task: A-only, V-only, AV congruent (AVc), and AV incongruent (AVi). Additionally, three generalization posttests are administered testing voiced fricatives, new real words, and a new speaker. Results show that post-training, the trainees reveal: (1) improvements corresponding to training type (e.g., the V-training group improves most for the V-only stimuli), (2) greater improvements for the familiar (but less visually distinct) alveolars than for the new interdentals, (3) decreased AV-fusion for the AVi stimuli, and (4) consistent patterns in the generalization tests. Results are discussed in terms of the effects of speech input modality, experience, and L1 on L2 AV speech learning. [Research supported by SSHRC]
Experimental study of the fluid-structure-acoustic interaction in a human voice model
Authors: Kniesburges Stefan , Becker Stefan , Mueller Stefan , Delgado Antonio , Link Gerhard , Kaltenbacher Manfred , Doellinger Michael
Published: May 2008

A fluid-structure-coupled in-vitro model was developed for the investigation of the physical processes of the human phonation. The setup enables to simulate self-sustained vocal fold oscillation and to analyse the resulting supraglottal flow field. Measurement techniques like high-speed flow visualization, Particle Image Velocimetry (PIV) of the time-dependent flow field, unsteady pressure measurement, vibration measurement by a Laser-Scanning-Vibrometer were applied. The acoustic field was simultaneously recorded. Analysis was performed regarding correlations between the acoustic field, the flow velocity and the displacement of the vocal folds. The results support the existence of the Coanda-effect during phonation as assumed in previous work. The flow attaches to one vocal fold just past the glottis and forms a spacious vortex behind the vocal folds. This behaviour is not linked to one vocal fold and changes stochastically from cycle to cycle. The analysis indicates, that the acoustic sound is primarily produced by the pressure fluctuation caused by the pulsating flow rate due to the opening and closing process of the vocal folds. We assume, that the structural sound and the turbulence-induced sound do have minor acoustical implication.
The role of source and filter cues in emotion recognition in speech
Authors: Sauter Disa , Eisner Frank , Rosen Stuart , Scott Sophie K.
Published: May 2008

In the context of the source-filter theory of speech, it is well established that intelligibility is heavily reliant on information carried by the filter, that is, spectral cues (e.g., Faulkner et al., 2001; Shannon et al., 1995). However, the extraction of other types of information in the speech signal, such as emotion and identity, is less well understood. In this study we investigated the extent to which emotion recognition in speech depends on filter-dependent cues, using a forced-choice emotion identification task at ten levels of noise-vocoding ranging between one and 32 channels. In addition, participants performed a speech intelligibility task with the same stimuli. Our results indicate that compared to speech intelligibility, emotion recognition relies less on spectral information and more on cues typically signaled by source variations, such as voice pitch, voice quality, and intensity. We suggest that, while the reliance on spectral dynamics is likely a unique aspect of human speech, greater phylogenetic continuity across species may be found in the communication of affect in vocalizations.
Influences of manner and voicing on articulatory coordination in German and French initial consonant clusters
Authors: Kuehnert Barbara , Hoole Phil , Mooshammer Christine , Bombien Lasse
Published: May 2008

This study aims for improved understanding of whether and how coordination patterns of supraglottal gestures in complex syllable onsets are driven by competing demands of motor economy for the speaker and high recoverability for the listener. Specifically, EMA data for four German and three French speakers was acquired for C1C2 clusters where manner of articulation was varied for C2 (/l/ vs. /n/) and voicing for C1 (/p/ vs. /b/, /k/ vs. /g/). Results (1): A robust effect of less overlap of the constriction gesture for C1 and C2 when C2 is nasal. Clusters with nasal C2 may require less overlap in order to avoid compromising the acoustic characteristics of the C1 burst by early velar lowering. Interestingly, such clusters appear to be less stable diachronically and may be less favoured for the formation of complex onsets because of reduced scope for efficient parallel transmission of segmental information. Results (2): For German, a consistent effect of less overlap for voiceless compared to voiced C1. Discussion here will centre on whether possible cross-language differences between German and French can be related to differences in timing of voice onset and resulting differences in the acoustic properties of the C1-C2 transitions.
Probing the independence of formant control
Authors: Macdonald Ewen , Burt Bryan P. , Munhall Kevin G.
Published: May 2008

Previous experiments in speech motor learning have demonstrated that acoustic feedback is used to control formant frequencies (Houde and Jordan 1998; Purcell and Munhall 2006; Villacorta, Perkell, and Guenther 2007). In these studies, the formants of a vowel were shifted using a real-time signal processing system. When subjects spoke a vowel, they heard themselves saying a different vowel. The talkers spontaneously compensated for this auditory feedback perturbation by producing formants in the opposite direction in frequency to the perturbation. The purpose of the present study was to investigate if compensating for a perturbation in either the first or second formant also leads to a change in production of the other formant. A between-subjects experiment was conducted where half the participants had a perturbation applied only to the first formant and the other half had a perturbation applied only to the second formant. As in previous experiments, both groups compensated for the perturbed formant. In compensating for the perturbed formant, the production of the other, unperturbed, formant was also affected. However, the change in frequency was quite small. The results will be discussed in terms of the independent variables of speech motor planning
Intraglottal pressures in a static physical model of the converging glottis: entrance loss coefficients, exit coefficients, Bernoulli effects, and viscous effects
Authors: Fulcher Lewis P. , Scherer Ronald C.
Published: May 2008

Pressure distributions were obtained with a static physical model (M5) at diameters d = 0.005, 0.01, 0.02, 0.04, 0.08, 0.16, and 0.32 cm for converging angles of 5, 10, 20, and 40 degrees. At each diameter and angle, transglottal pressures typically ranged from 3 to 15 cm H2O. For each angle, diameter, and transglottal pressure, the measured pressure at the glottal entrance was used to calculate an entrance loss coefficient, and the measured pressure near the glottal exit was used to determine an exit coefficient. Previous work with the uniform glottis, where the only important physical effect was viscosity, found linear fits to the intraglottal pressures to be excellent approximations. Since the widening channel of the converging glottis produces Bernoulli effects as well as viscous effects, a parabolic form for intraglottal pressures is explored. Such an analytic form for the intraglottal pressures when accompanied by tables of entrance loss and exit coefficients would be a useful tool for researchers needing expressions easily included in numerical models of phonation. The validity of the new analytic treatment will be assessed by comparing the calculated pressures with the observed M5 pressures. [Work supported by NIH R01DC03577.]
Fricative synthesis investigations using the transmission line matrix method
Authors: Katsamanis Athanasios , Maragos Petros
Published: May 2008

We investigate the potential of properly applying the Transmission Line Matrix method to simulate the 3D acoustic field in the vocal tract especially for the synthesis of fricatives. For fricatives, we are mainly interested in the higher end of the spectrum where the planar wave propagation assumption that is accepted in the one-dimensional simulation cannot provide accurate results. This is the main reason why we explore 3D acoustic field simulation. Proper incorporation of noise sources is considered to account for frication. Their placement and acoustic properties are investigated. Motivated by measurements of the airflow during fricative production, we also explore the influence of mean flow to acoustics in the tract. Sound propagation in moving medium is considered for this purpose. The applied vocal tract geometry is determined from 3D MRI images. We present computational considerations for the analyzed framework in parallel to potential benefits compared to the one-dimensional vocal tract simulation.
Chirplet Transform Analysis for Ultrasonic Inspection of Composite Materials
Authors: Benammar Abdessalem , Drai Redouane , Kechida Ahmed , Guessoum Abderrezak
Published: May 2008

In this work, a successive parameter estimation algorithm based on the chirplet transform is presented. The chirplet transform is used not only as a means for time frequency representation, but also to estimate the echo parameters, including the amplitude, time-of-arrival, center frequency, bandwidth, phase, and chirp rate. We initially apply this method to simulated signals with additional structural noise. These signals contain several echo defects, closer between them. This stage permits to see the robustness of the developed algorithm. Thereafter, we validate all simulated results by experimental results obtained on composite material with and without delamination defects.
Acoustic Source Localization via Distributed Sensor Networks using Tera-scale Optical-Core Devices
Authors: Imam Neena , Barhen Jacob
Published: May 2008

For real-time acoustic source localization applications, one of the primary challenges is the considerable growth in computational complexity associated with the emergence of ever larger, active or passive, distributed sensor networks. The complexity of the calculations needed to achieve accurate source localization increases dramatically with the size of sensor arrays, resulting in substantial growth of computational requirements that cannot be met with standard hardware. One option to meet this challenge builds upon the emergence of digital optical-core devices. The objective of this work was to explore the implementation of key building block algorithms used in underwater source localization on optical-core digital processing platform recently introduced by Lenslet Inc. We investigate key concepts of threat-detection algorithms such as Time Difference Of Arrival (TDOA) estimation via sensor data correlation in both time and frequency domains with the purpose of implementation on the optical-core processor. We illustrate our results with the aid of numerical simulation and actual optical hardware runs. The major accomplishments of this research, in terms of computational speedup and numerical accuracy achieved via the deployment of optical processing technology, should be of substantial interest to the acoustic signal processing community.
Averaged Lagrange Method for interpolation filter
Authors: Andrea Jonathan , Coutard Frederic , Schweitzer Patrick , Tisserand Etienne
Published: May 2008

This paper presents a new method for Lagrange interpolation for reducing distortions without introducing any complexity. The aim is to improve the linearity of the phase and the gain responses of the interpolation filter by an averaging method. A first FIR interpolation filter of the second order computes the values between three successive samples of the input signal. At the same time, a second filter, identical to the first, computes the values between (xk–2 , xk–1 , xk ). Finally, the common values between (xk–2 , xk–1 ) provided by the two filters are averaged two by two. This double interpolation can be simply done with a single third order filter and with a Farrow structure filter. Compared to the usual Lagrange's third order interpolation filter, the behaviour of the filter we propose is more regular especially in the high frequencies of the Nyquist band. More, the filter coefficients are easier to calculate. The designed filter is tested on a FPGA of Altera. The results shows that the method significantly reduces distortions and improves quality of the frequency response.
Application of digital filters for measurement of nonlinear distortions in loudspeakers using Wolf's method
Authors: Siczek Rafal
Published: May 2008

The design of digital filters used for measurement of nonlinear distortions in loudspeakers by the Wolf's method is presented in the paper. The Wolf's method has been developed in 1953 and originally the analog filters was applied. This method requires particularly steep slopes of both band-reject filters (at the transmitting part of the measurement system) and band-pass filters (at the receiving part). The digital filters allows for achievement of such steep slopes with a relatively small cost in comparison with analog ones. The very high attenuation in the barrage bands can be achieved. In the very narrow transition band any irregularities do not appear. The design procedures using MATLAB package have been described. Then, the digital filter allow for achievement of a high accuracy of measurement.
Detecting Scenes in Lifelog Videos based on Probabilistic Models of Audio data
Authors: Yamano Kiichiro , Itou Katunobu
Published: May 2008

Lifelog videos are recorded every activity in everyday lives. To utilize them efficiently, it is required to be indexed automatically. To index continuous shots of the lifelog, significant scenes are detected automatically. For detection, many researches employ image features such as color and edge, however, the accuracy is insufficient. In this study, we propose probabilistic models for scene detection from lifelog video. In this method, mel-frequency filter bank output of audio tracks of the lifelog videos is modeled statistically with hand-labeled training data. We tested the proposed method to use train station scene. We collected 11 hour sound data for such scenes. To analyze them, we defined seven categories, such as stopping trains, passing trains, starting trains, waiting, and so on. Our method achieved to 100% for waiting scene and 18.4% in average.
Characteristics of sound pressure field focused by an acoustic aplanat lens
Authors: Nakamura Toshiaki , Sato Yuji , Miyazaki Ayano , Mori Kazuyoshi
Published: May 2008

In this paper, we describe the characteristics of an acoustic aplanat lens which can eliminate both spherical and coma aberrations. A singlet aplanat lens was designed using a ray theory in paraxial area. Sound pressure fields of the bi-concave aplanat lens and a spherical lens with 160 mm in diameter for the frequency of 500 kHz were evaluated by a three-dimensional finite difference time domain (3-D FDTD) method. The aplanetic lens showed better convergence characteristics than spherical lens. Two bi-concave lenses of aplanat and spherical lenses were made by acrylic resin and water tank experiment was conducted to compare the on-axis characteristics and beam patterns at the focus of them. As a result, the aplanat lens could focus higher sound pressure than the spherical one within the incident angle of 10 degrees.
Echo analysis of objects on the seafloor
Authors: Li Xiukun , Chi Huiguang
Published: May 2008

Echoes from elastic objects on the seafloor comprise two kinds of acoustic components as well as bottom reverberation. One is elastic scattering echoes, and the other is geometric echoes. These echoes are called highlights, which can be used for identification of objects. Because time delay among highlights from small objects is very short, neither the wavelets resolved highlights structure nor suppressed bottom reverberation according to research. In order to obtain highlights structure and decay reverberation, the Hilbert Huang Transform (HHT), which is a new idea for analyzing nonlinear and nonstationary is applied in the paper. The HHT can describe the data from the instantaneous frequency and energy rather than the global frequency and energy defined by the Fourier spectral analysis, and the adjustable window Fourier spectral analysis defined by the wavelet. The results from both extensive simulations and real data show that the HHT has the highest resolution in time and frequency domain, and may prove to be a vital method for identification of objects on the sea floor.
Changing of scattering properties of underwater objects covered by elastic shell
Authors: Grelowska Grazyna , Gloza Ignacy
Published: May 2008

In certain situations it is of a great importance to decrease reflection properties of underwater objects positioned into water, deployed on a seabed or buried into sediments. This effect could be achieved by means of covering shell changing acoustic parameters of considered object. The aim of the paper is to present the idea of performing the covering material for underwater objects as well as results of experimental investigation of its scattering characteristics. Acoustic scattering measurements were performed in laboratory condition on solid air-filled objects of sphere or ellipsoidal shape with or without covering shell. The objects were insonified by acoustic source at frequency in range of 60 kHz - 150 kHz.
Can also diffracted sound be handled as flow of particles? Some new results of a beam tracing approach based on the uncertainty principle
Authors: Stephenson Uwe M.
Published: May 2008

In computational room acoustics as well as noise immission prognosis efficient ray or beam tracing methods are well approved - but the problem of the neglected diffraction is still unsolved in general. The author's successful approach of 1986 based on Heisenbergs uncertainty principle was extended to the more efficient beam tracing technique and presented at the ICA 2007. The algorithm has now been generalized to recursive higher order diffraction. Now, not only single edge, but also multiple edge diffraction could be simulated (slit and “wide obstacle” with two edges). The results have again been compared with Svensson's exact wave-theoretical secondary edge source model. With some restrictions, they seem to indicate, that indeed even diffraction of sound - like light - may be handled as flow of particles. To avoid the feared explosion of computation time with higher order diffraction, a beam reunification may now be achieved by Quantized Pyramidal Beam Tracing.
Maximizing field performance of thin, light-weight partition and floor assemblies
Authors: Eligator Ronald
Published: May 2008

Laboratory test reports are an important source of information regarding anticipated performance of a sound barrier construction. However, differences in construction conditions between the laboratory and a real building can greatly affect, usually negatively, the performance of a sound barrier assembly in the field. This reality, combined with the typical client's focus on reducing construction costs, requires that for a sound barrier construction to be successful, the effect of abutting constructions must be well understood. This paper reports on our firm's experience in translating lab-tested light-weight sound barrier assemblies to the field, relating design conditions to field results in terms of physical construction and noise reduction results.
Influence of static-load on airflow resistivity determination
Authors: Schiavi Alessandro , Guglielmone Claudio , Miglietta Piercarlo , Alasia Franco
Published: May 2008

Dynamic stiffness of resilient materials used as underlayer in floating floors give useful knowledge on the acoustical behaviour of a floor in impact sound insulation. In previous works the influence of the static load and the compressive behaviour of the resilient layers on dynamic stiffness evaluation has been shown. A new measurement technique of the airflow resistance (according to ISO 9053) in terms of static load applied on the resilient materials with open cells is proposed. Usually the airflow resistance of porous materials used as underlayers is evaluated on unloaded samples of material. In dynamic stiffness measurements the material is subject to a static load of 2 kPa. Because the dynamic stiffness value depends on airflow resistivity r [Pa×s/m2] (in particular when 10 kPas/m2< r <100 kPas/m2) through the material, it is important to evaluate the airflow resistivity behaviour in the same condition of the dynamic stiffness measurement, i.e., under a static load of 2 kPa. A new apparatus to evaluate the airflow resistivity in terms of different static loads has been designed and realized at I.N.RI.M. of Turin. The first experimental results show evidence of the dependence of the airflow resistivity of the resilient materials on the applied load.
Compression of felt-type thermal insulation layer for underfloor heating system and floor impact sound
Authors: Cho Tongjun , Kim Hyun-Min
Published: May 2008

In Korea, almost every house uses underfloor heating, which has advantages of thermal comfort and energy efficiency. However, when it is constructed for high-rise apartment houses, it yields a problem in floor impact sound insulation. It accounts for the fact that a foam-type thermal insulator sandwiched between structural slab and heating floor functions as a spring and easily transmits impacts on the floor to the slab. In that case, the system's transmissibility is determined by dynamic stiffness of the thermal insulation layer and the lower the dynamic stiffness is, the more the floor impact is isolated. For that reason, apartments construction companies are attempting to lower the dynamic stiffness of the thermal insulation layer for impact sound reduction. As part of the attempt, felt-type materials with relatively low dynamic stiffness such as glass wool or polyester felt are considered as a substitution for the foam-type thermal insulator. However, there is a possibility that compression of the felt-type materials would increase the dynamic stiffness and the impact sound insulation effect at early stage might be weakened in the long term. This paper investigates the correlation between gradual compression of the felt-type thermal insulation layer and the impact sound variation.
The acoustical effect of reveal blocks, from measuring method to prediction
Authors: Reis Frigyes , Tóth Balázs
Published: May 2008

The analysis of the efforts to create high quality building from the point of view of energy-efficiency, and the resulting variety of new products, building constructions and systems leads to the conclusion: there are characteristic deficiencies in the field of measuring and prediction methods related to sound insulation, and there is a need to stop the gap. The example on which the problem is shown is the acoustical effects of reveal blocks, used around window openings, to reduce heat propagation and increase energy efficiency. The reveal blocks include more sound propagation paths, the sound insulation of which can not be determined using the existing measuring standards. The paper describes new measuring concept and method to characterise the sound insulation characteristics of reveal blocks in their built-in form. The methods are fitted to the standardised measuring methods of sound insulation. Proposal is presented for the modification in the prediction procedure of sound insulation of façade constructions, utilising the results of the new measuring method.
Survey on the insulation performance of acoustic louvres
Authors: De Geetere Lieven , Ingelaere Bart
Published: May 2008

Machinery such as compressors, boilers and generators require adequate ventilation and extract. To avoid excessive noise breakout, acoustic louvres are frequently used. These are usually made of tilted hollow metallic blades filled with absorptive materials and perforated at the inside face. This study investigates the important characteristics of common shaped acoustic louvres with regard to sound insulation. First, a market survey on 109 existing acoustic louvres of 24 producers worldwide is made. Second, laboratory measurements of sound insulation on 38 prototypes of 1 m2 acoustic louvres are compared. The influence of several parameters are studied such as louvre depth, blade angle, blade shape, blade thickness, blade spacing, kind of absorptive material, perforation degree, and edge filling.
Size-adaptive spherical receptor acceleration method for acoustical ray tracing
Authors: Lesoinne Stéphane , Embrechts Jean-Jacques
Published: May 2008

Randomized ray tracing in room acoustics can be used to compute echograms, but the results computed at the receptor are affected by statistical errors [1]. To decrease these statistical errors, the usual solution is to increase the number of rays, but this also increases the computation time. Another solution is to increase the receptor size, but this lowers the spatial resolution of the computed sound field, which is particularly important for the early part of the echogram. In order to decrease the computation time and keep a sufficient resolution, the method proposed in this paper is based on a progressive modification of the receptor size (spherical type) as long as the ray's travel grows. At the same time, the number of rays into the room can be decreased as the sound ray lengths increase while keeping the statistical errors more or less constant. The consequence is that the sound field spatial resolution evolves from “precise” at the beginning of the echogram to “rough” at its end. The first applications of this new method show a significant gain of CPU time. [Broad spectrum diffusion model for room acoustics ray-tracing algorithms, J. J. Embrechts, Jnl. Acoust. Soc. Am. 107(4) 2068-2081 (2000)].
Detection of beaked whales using near surface towed hydrophones: prospects for survey and mitigation
Authors: Gillespie Douglas , Gordon Jonathan , Caillat Marjolaine , Claridge Diane , Moretti David , Boyd Ian
Published: May 2008

Beaked whales are extremely difficult to sight at sea and this hampers attempts to study them, and makes real time mitigation difficult. Passive acoustic monitoring could improve detection efficiency. Blainville's beaked whales, (Mesoplodon densirostris) are known to produce most of their vocalizations at depth. They are routinely detected on bottom mounted hydrophones arrays but the extent to which they can be detected using near-surface hydrophones is not known. Continuous recordings were made at a sampling rate of 192 kHz from towed hydrophone arrays during line transect surveys in the Bahamas in conjunction with teams monitoring bottom-mounted hydrophones at the AUTEC Tongue of the Ocean navy range. A beaked whale click detector and classifier was developed within Rainbow Click and PAMGUARD and this was both run in real time and used to analyze recordings to pick out beaked whale click trains. Detected click trains correlated well with detection of beaked whales on bottom-mounted hydrophones. Three species of beaked whale were encountered visually and detected acoustically: Mesoplodon densirostris, Ziphius cavirostris and Mesoplodon europaeus. Target motion analysis of bearings to sequences of clicks suggests a maximum detection range of approximately three kilometers and preliminary results indicate that clicks can be identified to species.