bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound insulation of artificial and natural sound signals in reeds habitats
Authors: Ianovschi Igor , Osipova Ludmila
Published: May 2008

From the point of view of acoustical communication, dense fields of reeds are strong acoustical filtre which distorts original sound signal. In this research the rate of sound signals sound insulation in massives of reeds was estimated. As a models were used artificially synthesized, modulated by frequency signals of three frequency lines: 1-2 kHz, 2-4 kHz, and 4-8 kHz with duration of 0.1 and 0.25 msec. For comparison were also used elements of bird songs. The least damping was noted in signals with descending frequency modulation in 8 - 4 kHz range in the upper level of reeds (6 db on 10 m). The most damping were noted in signals with descending frequency modulation in 2 - 1 kHz in the middle level of juncaceous massive(18 db to 10 m). The signals with frequency modulation of 4-2 kHz were extending better in the upper level of reeds (7-8 db), whereas in the lower and upper levels were noted dependence of damping rate on duration of sound impulse - the signals with duration of 0.25 mec were damping less than signals with duration of 0.1 msec . The elements of bird songs during their emission in the middle level of juncaceous massive were damping by 15-20 db on 10 m.
Echolocation and flight strategies of Japanese house bats (Pipistrellus abramus) to attack a prey in the field revealed by a microphone array
Authors: Fujioka Emyo , Mantani Shigeki , Fukuda Michihiro , Hiryu Shizuko , Riquimaroux Hiroshi , Watanabe Yoshiaki
Published: May 2008

Bats are supposed to have effective strategies for achieving a good balance between echolocation and flight behaviors while capturing small moving insects in the field. To reveal their strategies for catching insects, we successfully reconstructed 3-D flight trajectories for the bat to forage in the field by a four-microphone array system, and conducted both acoustical and behavioral analyses for capturing behavior. Data show that the flying bats changed their flight direction flexibly, and sometime repeated capturing insects every two to three seconds. During the search phase, the bat moved 0.5-0.8 m during an interval between successive pulses (IPI) and then decreased that the moving distance during an IPI up to 0.1 m just before capturing a prey. Interestingly, we found that the bat tended to descend toward a prey from above when the approach phase started. This suggests that foraging bats may effectively utilize gravity for an easy acceleration toward the prey to concentrate on the complex echolocation for capturing moving insects. [Supported by a grant to RCAST at Doshisha Univ. from MEXT of Japan: Special Research Grants for Development of Characteristic Education from the Promotion and Mutual Aid Corporation for Private Schools Japan, Innovative Cluster Creation Project.]
Some problems of analyzing bio-sonar echolocation signals generated by echolocating animals living in the water and in the air
Authors: Gudra Tadeusz , Herman Krzysztof
Published: May 2008

In this paper some similarities and differences of bio-sonar echolocation signals generated in the water and in the air are presented. The echolocation cues of marine mammals and bats are usually frequency and amplitude signals modulated simultaneously. The main problems of the analysis of such type of signals are envelope detecting and time-frequency decomposition. In this paper some digital signal processing (DSP) algorithms that may be used to analyze this type of signals are presented. The basic linear spectrogram (STFS), the nonlinear Winger-Vill'e spectrogram and some time-scale representations of signals using wavelets methods of estimation of the frequency modulation function have been compared. An analysis of possibilities for acoustic identification of particular species of bats by means of echolocation is also presented.
Burst pulses produced by free-ranging bottlenose dolphins in Tampa Bay, Florida and Mississippi Sound, Mississippi
Authors: Lace Natalija , Kuczaj Stan A. , Lammers Marc O.
Published: May 2008

Investigations of the bottlenose dolphin's acoustic repertoire have mainly focused on whistles and echolocation clicks. However, despite their widespread occurrence, burst pulses have not received much attention. The primary function of burst pulses remains unknown and a comparative analysis can be used to advance our knowledge of the function of burst pulses. We recorded the acoustic repertoires of free-ranging bottlenose dolphins in the Tampa Bay and Mississippi Sound areas using broadband recording equipment. The two habitats differ in their environmental features, including water temperature, ambient noise levels and water turbidity. Our preliminary data show that several acoustic parameters such as peak frequency and center frequency of burst pulses differ among habitats. We also report other acoustic parameters, such as the number of clicks, inter-click interval, 3-dB and rms bandwidth. In our ongoing study, we will examine relationships between environmental features of the habitats and the acoustic characteristics of burst pulses.
Real-time acoustic monitoring of the deep-ocean environment
Authors: Andre Michel , Van Der Schaar Mike , Mas A. , Roma A. , Castell J.v. , Morell Maria , Solè M. , Rolin J.f. , Person Roland
Published: May 2008

ESONET is a European Network of Excellence (NoE) associating 50 partners (research centres, universities, industrials and SMEs) from 14 countries: France, Germany, Italy, UK, Spain, Portugal, Greece, Belgium, Ireland, the Netherlands, Norway, Sweden, Bulgaria, and Turkey. More than 300 scientists and engineers will participate to its activities. The aim of the ESONET NoE is the lasting integration of European research on deep-sea multidisciplinary observatories. ESONET is particularly sensitive on the effects of noise on marine organisms. Because our knowledge is still quite limited, ESONET is developing a Demonstration Mission, called LIDO, Listening to the Deep-Ocean Environment, a research program that will help establishing a scientific base to allow (1) the real-time automatic identification and classification of nonbiological and biological sounds, (2) the monitoring of marine organisms and population dynamics, (3) the assessment and control of the long term effects of anthropogenic sources on marine organisms, (4) the education of the public, end-users and the administration, and (5) the approval of ethical guidelines and procedures. This latter point constitutes a major criterion to award the ESONET LABEL to the observatories. This paper presents the data management architecture and the RT analysis processes that will be carried out at the observatories.
Testing the acoustic tolerance of harbour porpoise hearing for impulsive sounds
Authors: Lucke Klaus , Lepper Paul A. , Blanchet Marie-Anne , Siebert Ursula
Published: May 2008

The planned construction of offshore wind turbines in the North and Baltic Seas involves the emission of high numbers of intense impulsive sounds when the foundations of the turbines are being driven into the ground by pile driving. Based on information from other odontocete cetaceans it can be assumed that the source levels which will on average exceed 225 dB re 1 μPa pose a risk at least for temporary threshold shift (TTS) on harbour porpoises which inhabit these waters. In order to base the definition of noise exposure criteria on information on the tolerance of the hearing of this species a TTS study was conducted on one of the harbour porpoises held at the Fjord and Baelt in Kerteminde, Denmark. The hearing data were collected by using the AEP method. An airgun was chosen as sound source for the fatiguing sound stimulus to simulate the impulsive sounds at sufficiently high levels. This study comprises the testing of the animals normal hearing sensitivity and subsequent repetitions of these tests after an exposure to single impulsive sounds from the airgun at increasing levels. The baseline hearing data, thresholds for behavioural reactions and the resulting TTS levels will be presented.
High-resolution population density imaging of random scatterers through cross-spectral coherence in matched filter variance
Authors: Andrews Mark , Gong Zheng , Cocuzzo Daniel , Ratilal Purnima
Published: May 2008

The matched filter enables imaging with high spatial resolution and high signal-to-noise ratio by coherent correlation with the expected field from what is assumed to be a discrete scatterer. In many imaging systems, however, returns from large numbers of scatterers are received together and the coherent or expected field vanishes. This is the case when imaging schools of fish, other groups of marine life, or other diffuse scatterers in sonar or ultrasound applications. Here we show that despite the absence of an expected field, cross spectral coherence in the matched filter variance retains a pulse compression property that enables high-resolution imaging of scatterer population density. Both analytic and numerical models are developed for active imaging systems. We show the conditions for when the coherent intensity can be neglected. The model is implemented for several scenarios where single scattering dominates and also for cases where multiple scattering is important. It can applied to imaging in both free space and waveguide environments.
Dual-mode ultrasound array (DMUA) systems for noninvasive surgery
Authors: Ballard John , Wan Yayun , Ebbini Emad S.
Published: May 2008

Advances in microelectronics and piezocomposite transducer technology have made it possible to design, fabricate, and test therapeutic arrays with imaging capabilities suitable for image-guided noninvasive surgery. Prototype DMUAs have been recently tested and were shown to be capable of generating therapeutic HIFU beams suitable for tissue ablation while intermittently imaging the target volume before, during, and after lesion formation. An additional advantage of imaging with DMUAs is the potential for identifying critical regions in the treatment field for targeting or avoidance by the HIFU beam. We have developed an image-based refocusing algorithm that allows for maximizing the power deposition at the location of HIFU focus while minimizing the power deposition at critical targets to be avoided. Grayscale images obtained using the DMUA are used to define the coordinate of the target and the grid points in the treatment region. A major application of this capability is the targeting of liver tumors by large-aperture arrays in the presence of the rib cage. In this paper, we present experimental validation of this algorithm in vitro. Quantitative analysis of the improvements in the quality of the HIFU beam at the target will be presented and discussed.
Transducers for reduced aberration in HIFU by nonlinear harmonic focusing
Authors: Clement Gregory , White Jason
Published: May 2008

We have been investigating a low-frequency transducer design that promotes the divergence of the low frequency beam while promoting the focusing of nonlinear-induced higher harmonic frequencies. In this manner, a low frequency - and thus less absorbed and less distorted - beam is passed through the near field, peaking before the buildup of higher-frequency components. The high frequency components are then focused by means of the wavefront design. Using this approach, we expect reduced distortion of the ultrasound focus, while allowing a beam that uses mechanical or thermal effects for ablation, as opposed to cavitation. In our preliminary study we have been working to establish feasibility of the approach. Two source transducers (0.272 MHz and 0.272 MHz) with identical geometries were used to propagate through ex vivo human skull, representing strong nearfield aberration. Transmitted fields were scanned after transsskull propagation with a pvdf needle hydrophone. Reconstructions were performed at the fundamental frequencies for both scans, and for the 0.272 MHz transducer, an additional reconstruction was performed at its second harmonic (by design 0.544 MHz). The harmonic signal was observed to be significantly less distorted than the same frequency directly propagated from the transducer. A numeric study for optimizing the method will also be presented.
Progress towards transducers and arrays for real-time high frequency biomedical ultrasound imaging
Authors: Cochran Sandy , Bamber Jeff , Bernassau Anne L. , Bush Nigel , Button Tim W. , Demore Christine E. , Garcia-Gancedo Luis , Hutson David , Maclennan Duncan P. , Maher Paul M. , Meggs Carl , Webster Rhiannon A.
Published: May 2008

As research into transducers and arrays for real-time high frequency biomedical ultrasound imaging continues, it is becoming increasingly clear that major applications exist for systems with significantly higher spatial resolution than those already available for human clinical imaging. A key area of research remains the design and fabrication of the transducer or array. It is now accepted that piezocomposite is the material of choice and composite design and conventional dice-and-fill fabrication techniques have been optimised to allow 40 MHz operation, corresponding to wavelengths around 40 um. This expands the range of applications of piezocomposites but is still limited in terms of resolution of fine structures, for example at cellular level and to explore harmonic imaging. In this paper, we report continuing progress in work on new design techniques and fabrication processes with the potential for fabricating arrays that operate up to 100 MHz. The net-shape micromoulding fabrication technique for the ceramic within our composites is outlined, new single element transducer designs and array fabrication based on advanced surface finishing and photolithographic processes are described, and results are presented illustrating key performance data such as the point spread function, insertion loss and imaging of post mortem human tissue.
Lead magnesium niobate-lead titanate single crystal thick films on silicon substrate for high-frequency micromachined ultrasonic transducers
Authors: Peng Jue , Chao Chen , Dai Jiyan , Chan Helen L. W. , Luo Haosu
Published: May 2008

Some new clinical applications requiring ultrasonic frequencies higher than 30 MHz are emerging, such as ophthalmological and dermatological imaging and intravascular imaging with probes mounted on catheter tips. High frequency ultrasonic transducer (HFUT) has thus been a growing research area in recent years. Most of the HFUTs reported are using piezoelectric PZT ceramic thin plates, ZnO films or PVDF films as the transducer materials. The PMN-PT ((1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3) single crystal, although possessing the highest piezoelectric coefficients, has seldom been used for this purpose because it is difficult to lap down the brittle single crystals to thin plates and handle them in conventional way of transducer fabrication. In this work, a novel high-frequency ultrasonic transducer structure is realized by using PMN-PT-on-silicon technology and silicon micromachining. A hybrid processing method involving wafer bonding, mechanical lapping and wet chemical thinning is successfully developed. PMN-PT thick films with thickness ranging from several to tens of microns have been demonstrated and they have properties comparable to those of PMN-PT bulk samples. A prototype high frequency ultrasonic transducer is being fabricated and characterized. Acknowledgement Financial support from the Innovation and Technology Fund (K-ZP21) is acknowledged.
Microelastic imaging of mineralized tissues - Principles and applications in musculoskeletal research
Authors: Raum Kay
Published: May 2008

High frequency ultrasound has become one of the most powerful tools for microelastic characterization of hard biological materials. A major advantage is the possibility to map not only the microstructure, but also the heterogeneous anisotropic elasticity of mineralized tissues. Quantitative concepts for deriving anisotropic elastic parameters with frequencies from 50 MHz to the GHz range will be presented. Due to the scalability ultrasound can be applied for large animal studies, e.g., to predict the mechanical stability in sheep tibiae after callus distraction, as well as for small animal models, e.g., to study the effects of genetic differences in inbred strain mice. Moreover, SAM data are suitable for numerical deformation or sound propagation analyses on “real- life” models. Such models are crucial for the development and validation of new non-invasive diagnostic tools dedicated to the prediction of an individual fracture risk. For example, it has been shown that the velocity of the first arriving signal - measured with the axial transmission technique at the radius - can be predicted by a nonlinear combination of fracture determining parameters, i.e., porosity, cortical thickness and tissue elasticity, assessed by 50-MHz SAM. These findings may lead to the establishment of pathology specific treatment and regeneration monitoring strategies.
Wave propagation modes and arterial stiffness
Authors: Bernal Miguel , Greenleaf James
Published: May 2008

Arterial elasticity is an independent predictor of cardiovascular disease and mortality. Measurment of waves in thin shells can be used to estimate the circumferential and the longitudinal elastic moduli. Latex tubes and excised pig arteries were used as isotropic and anisotropic models. Waves were generated using focused ultrasound (1 ms, 3 MHz) in different locations of the wall. The modes of propagation of the waves were detected with a laser vibrometer or an ultrasound pulse echo tool while the excitation was moved known distances. Bending waves were predominant when exciting in the center of the wall, while a combination of torsion and bending waves resulted from exciting off center. Wave speeds of 15 m/s and 5 m/s respectively, were measured for the bending waves. Using the Moens-Korteweg equation, values of 1.1 and 0.350 MPa were found for the longitudinal elastic modulus in the tube and artery respectively. Generation of different modes in the tubes and arteries is possible using focused ultrasound. Elastic components of the tubes and vessels in the longitudinal and the circumferential direction can be estimated from the speed of propagation and the frequency of the bending and the torsional waves.
Biomedical applications of radiation force generated in standing ultrasonic waves
Authors: Ostrovsky Lev , Sarvazyan Armen
Published: May 2008

This talk presents an overview of physical basis for the action of acoustic radiation force on particles in standing waves in relation to biomedical applications. The effect itself is known since the 19th century (Kundt, 1974) and its biomedical significance was demonstrated in 1971 by Dyson et al. However, despite a long history, extensive studies of particle behavior in standing ultrasonic waves have started only during the last decade due to numerous emerging biomedical applications. The range of currently explored applications is broad: targeted drug and gene delivery, increasing sensitivity of biosensors and immunochemical tests, manipulating cells in suspensions, microstirring, and others. The presentation will focus on theoretical analysis and applications of radiation force acting on particles and bubbles in the standing ultrasonic fields. Dynamics of particle motion induced by ultrasonic radiation force as a function of frequency, intensity, and other variables will be considered. The principal difference in interaction of ultrasonic standing wave field with solid particles and with bubbles due to resonant properties and high compressibility of the latter will be quantitatively analyzed. Several specific biomedical applications of the analyzed phenomena will be discussed.
Modeling the modulated acoustic radiation force distribution in a viscoelastic medium driven by a spherically focused ultrasound transducer
Authors: Meral Faik Can , Royston Thomas J. , Magin Richard L.
Published: May 2008

Acoustic radiation force created by focused ultrasound transducers is gaining great interest in medical diagnosis. This study aims to clarify the acoustic power delivery by means of a modulated focused transducer and to predict the performance of such systems. A spherical-cap shaped transducer, made of piezoelectric material, is used to create ultrasonic waves at a focal point. Different modulation methods, given in the literature and reviewed here, are available for creating a concentrated alternating force due to the acoustic radiation pressure. The relationship between the voltage input to the piezoelectric transducer and its resulting mechanical deformation is examined using a finite element model (FEM) for high frequency harmonic excitation (3 - 10 MHz). The oscillating surface of the transducer drives the contacting media, which exerts an acoustic load on the transducer that is also considered in the FE analysis. Also, the motion of resulting acoustic waves in a lossy medium is studied for a more accurate estimation of the induced force distribution and energy dissipation within the medium. Ultimately, the intention of this work is to relate the electrical power input to the transducer to the resulting dynamic force generated in the coupling medium. [Research supported by NIH Grant # EB004885.]
Ultrasound stimulated vibrometry for measuring tissue properties
Authors: Greenleaf James , Chen Shigao , Zhang Xiaoming
Published: May 2008

Harmonic or pulsed radiation pressure and subsequent measurement of the tissue response can be used to accurately quantitatively measure fundamental material properties of tissue. The measurement of shear wave dispersion can be used to estimate elastic shear moduli of tissue using an appropriate model. Fundamental model free properties such as complex modulus can also be measured. Ultrasound radiation pressure is used to induce free propagating shear waves. The measurable properties of the shear waves such as speed are sensitive to only the local material properties of the tissue under certain circumstances. A model relating the shear wave speed as a function of frequency is related to the elastic and viscous moduli within small regions of tissue according to, for instance, the Voigt model. Shear and elastic moduli in tissue are measured with high accuracy and precision given appropriate models of wave propagation within the geometry of the tissue. Complex modulus in liver of live pig and other tissues have been made. Careful use of shear wave propagation and subsequent measurements can provide fundamental quantitative measurements of tissue mechanical properties if models are accurate. An application of this method is the noninvasive measurement of liver stiffness as a surrogate for fibrosis.
Supersonic shear imaging: a multiwave imaging example
Authors: Fink Mathias , Tanter Mickael , Bercoff Jeremy
Published: May 2008

A new imaging method that relies on the simultaneous use of both a low frequency shear wave and a high frequency ultrasound is described. The shear waves have typically centimetric wavelengths and they propagated at low velocity in tissues. They are progressively distorted by the viscoelastic inhomogeneities of encountered tissues. When coupled to an ultrafast ultrasound scanner (5000 images per second), it allows for the follow up of the propagation of these waves with a millimetric resolution over a large zone of interest. From the spatiotemporal evolution of the shear displacement fields, inversion algorithms are used to recover the shear modulus and viscosity map with submillimetric resolution. These techniques are no more diffraction limited because, the near field of the transient waves is directly observed. In this multivave technique, the shear wave gives the contrast while the ultrasonic wave gives the spatial resolution. Shear waves are generated leveraging the innovative use of the ultrasonic radiation force generated by an ultrasound probe. A supersonic shear source is remotely created in tissues. Such a moving source creates two plane shear waves propagating in a Mach cone. In vivo images obtained in breast, liver, muscles will be presented that show the great interest of this quantitative imaging technique.
Experimental validation of the amplitude-modulated harmonic motion imaging for tissues stiffness estimation
Authors: Maleke Caroline , Luo Jianwen , Gamarnik Viktor , Konofagou Elisa
Published: May 2008

It has been previously shown that amplitude-modulated harmonic motion imaging (AM-HMI) has the capability of induce and image tissue displacement during the application of an oscillatory radiation force. Here, we aim at validating theoretical HMI findings with experimental results on similar phantoms. A finite-element-method (FEM) was first used to model a dynamic response of phantoms with inclusions at different stiffnesses and sizes. The FEM and experimental results were compared and used to describe the behavior of the locally displaced tissue. The radiation force was generated by a 4.68 MHz FUS transducer modulated at 50 Hz with acoustic pressure levels varied between 1.2 and 4 MPa. A 7.5 MHz pulse-echo transducer was placed through the center of the FUS transducer and used to image the displaced tissue. A 1D-cross-correlation method on successive RF signals was used to estimate the axial-displacement. The FEM and experimental results displayed good agreement in displacement patterns, i.e., the highest localized displacement occurred at the focus and was symmetrically distributed. In addition, mechanical testing was performed to estimate the phantom-gels moduli. A linear relationship between HMI displacements and tissue Young's moduli was established within the range of 13-to-50kPa. Further studies will involve the implementation of 1D linear-array transducer for full-view imaging.
An integrated system to deliver impulsive radiation force and to image induced transient strain for monitoring focused ultrasound surgery
Authors: Berry Gearoid , Bamber Jeff , Ma Yixin , Rivens Ian , Ter Haar Gail
Published: May 2008

Thermal coagulation of tissue causes an approximate three-fold increase in stiffness, which can be easily detected by various elasticity imaging methods. Advantages have been reported, for application to breast cancer diagnosis, of an elasticity imaging method that applies a highly localised transient stress deep within the tissue using a low frequency focused ultrasound radiation force impulse, and uses relatively high frequency echo imaging to measure the transient strain generated in the tissue placed between the transducers. In this paper we describe a new system that implements this concept using a focused ultrasound surgical transducer to apply the transient (<10 ms) load, synchronized by a customised field programmable gate array to a Zonare C5-2 probe to image the strain. Both transducers are on the same side of the tissue and locked together for scanning to create transient strain elastograms. Performance measurements, obtained using gelatine phantoms and ex vivo thermally ablated liver tissue, indicate an elastogram spatial resolution of 2 mm, and acceptable contrast for detecting regions of thermally coagulated tissue. An advantage of this configuration is that it may be easily integrated into focused ultrasound therapy.
Use of radiation force for enhancing efficacy of molecular targeted ultrasound contrast agents - in vitro and in vivo
Authors: Hossack John A.
Published: May 2008

Intravenously injected modified ultrasound microbubbles possessing molecule specific targeting ligands hold significant promise as a method for “molecular imaging.” Unfortunately, although microbubbles can achieve specific adhesion in regions of vascular pathology, the method breaks down in high blood flow regions where the bond formation process is more problematic. I present results indicating that acoustic radiation does increase the specific targeted adhesion of microbubbles by pushing the bubbles towards the periphery of a vessel. During in vitro studies, radiation force enhanced microbubble adhesion up to 60-fold. Microbubble adhesion is observed to increase approximately with the square of acoustic pressure between 25 and 122 kPa, but decreases at higher pressures as the bubbles rupture. Our in vivo studies involved using intravital microscopy to assess the adherence of P-selectin targeted microbubbles in the mouse cremaster microcirculation and femoral vessels. Acoustic radiation force enhanced microbubble retention four-fold in cremaster venules and in the femoral vein. A 20-fold enhancement was observed in the femoral artery. I discuss the potential for derivatives of the technique to provide molecular targeted therapeutic contribution.
Indirect acquisition of flutist gestures: a case study of harmonic note fingerings
Authors: Verfaille Vincent , Wanderley Marcelo M. , Depalle Philippe
Published: May 2008

The indirect acquisition of musicians' gestures consists in retrieving information about gestures from the sound. Inspired by previous studies investigating clarinetists' gestures, we focus on the flute, which features numerous playing modes and a rich palette of sounds. Our goal is to provide musicians with guidelines for using indirect acquisition. For a variety of playing modes, we collected information about gestures, body parts involved, and effects on the acoustical signal. We then designed signal processing algorithms for recognizing which gesture is involved in a given sound; later we will quantize related movement by combining direct acquisition, indirect acquisition and motion capture. Focusing on harmonic note fingerings, a first experiment investigated octave-related harmonic note fingerings with 1 nonexpert performer (ff dynamics and normal articulation). A target F0-guided PCA on the amplitude of the first six harmonics of F0/4 from 1 semi-tone frequency bands retrieved the correct fingering with two principle components in all trials. A second experiment investigated octave and non-octave related harmonic note fingerings with four expert performers. A target F0-guided PCA on the sum of energies around iF0/k (k=2,...,6; i=1,...,12) provided wider clusters, making more difficult to retrieve the correct fingering in some specific cases that we will discuss.
Foundations of sound therapy
Authors: Reznikoff Iegor
Published: May 2008

In the practice of music therapy, the use of the sounds of a live naturally singing voice appears to be the most effective; in some cases, results are obtained whereas there are no results using musical sounds, and generally results are obtained in a much shorter time. Sounds and singing in just intonation are particularly efficient. This practice introduces to a deep understanding of sound therapy. Sketched here are the vocal sound/body relationship and the vocal sound / consciousness relationship, which are relevant in this therapy. Finally clinical examples are given (coma states, loss of speech, old persons, states close to death, mind handicapped persons, depression, etc.). Bibliography I. Reznikoff: On Primitive Elements of Musical Meaning, www.musicandmeaning.net, Journal of Music and Meaning 3 (Invited papers), 2005.
Auditory resolution in virtual environments: Effects of spatialization algorithm, off-center listener positioning and speaker configuration
Authors: Marentakis Georgios , Peters Nils , McAdams Stephen
Published: May 2008

We present the results of an empirical study on the effects of room and off-center listener positioning on sound localization in two virtual environments, VBAP and Ambisonics. Localization accuracy has been assessed by estimating Minimum Audible Angles and Minimum Audible Movement Angles for the two spatialization algorithms and for three directions of sound incidence, in the studio and a concert hall for listeners in off-center listener positions, with two loudspeaker setups. A model of localization accuracy as a function of the experimental variables is presented, that can be used to quantify the effects of the room and off-center listening positions on sound localization and auditory movement detection.
Finite element modelling of steelpan acoustics
Authors: Gay Derek A.
Published: May 2008

In this paper the finite element method is used to model acoustic vibrations of steelpan shells. The steelpan surface is characterized as a three-dimensional compound shell, comprising notes (surfaces with reverse curvature) on a concave ellipsoidal surface attached to a cylindrical shell (the skirt). In this model note and inter-note surfaces are defined by geometric parameters which can be varied to define complex surface geometries. The geometric mesh model is used develop tenor, cello and bass steelpans instruments and a 3D finite element shell vibration algorithm is used to demonstrate their vibration characteristics. Modes shapes and frequencies of the composite shell structures are computed for typical configurations of note and skirt geometry. The model demonstrates that there exist many composite natural modes of a playing surface involving the interaction between two or more notes. In addition, it is found that the frequency range of mode shapes associated primarily within skirt vibration overlaps with the musical range of the notes underscoring the potential for “skirt-note” coupling. The degree of frequency overlap was found to be largely dependent on skirt length and configuration.
The perceptual and cognitive nonlinearities underlying musical preference across multiple exposures
Authors: Margulis Elizabeth H. , Roy Anil K. , Wong Patrick C.
Published: May 2008

Repetition is a fundamental part of engagement with the auditory world. Repeated exposures influence what gets perceived as important and what features are singled out for attention. That repetition can also influence the mysterious phenomenon of aesthetic enjoyment is a longstanding observation to which much intellectual attention has been paid. A special case of repetition and perceptual learning is music, a domain in which people choose to be exposed to the identical stimulus again and again. This apparent preference for repeated exposures connects fundamentally to notions of human identity, affect, cognitive processing, and neural function. We report on a set of experiments that uses behavioral measures to assess perceptual changes across multiple exposures (five over one week) of a 20-minute piece for orchestra. Across the five exposures, we found an inverted U-shape preference response, which possibly is decomposable to the complex interaction of multiple nonlinear components, represented by performance on tasks relating to memory, attention, affect, syntax, and error detection We argue that musical preference has remained a puzzle because the behavior depends on an underlying complex system with numerous nonlinear cognitive components revealed by our results. [Work supported by NIH, NSF, and Northwestern University.]
Single sensor singer/music separation using a source/filter model of the singer voice
Authors: Durrieu Jean-Louis , David Bertrand , Richard Gaël
Published: May 2008

Separating the singer voice from polyphonic music signals has many useful applications, such as demixing/remixing, desoloing or audio indexing. In the works of Benaroya on single sensor blind source separation, the signals are modeled by Gaussian mixtures (GMM) such that each state is characterized by a spectral shape. The separation itself is then done by adaptive Wiener filtering. However, to better fit general signals, the number of states for the vocal model should be equal to the number of notes multiplied by the number of vowels (or canonical vocal tract shapes) that the singer uses. Therefore, in order to separate a singer voice from background music, we suggest a source/filter model for the singer signal, keeping the same models as used by Benaroya for the background music signal. Assuming the presence of only one singer, we separate the desired part from the rest by first estimating the sung melody thanks to the source part of our model and then re-evaluating the parameters of our model. This research is partly supported by the European Commission under contract FP6-027026-K-SPACE and by the French AII (Quaero project).
Initialization, distances and local minima in audio applications of the non-negative matrix factorization
Authors: Bertin Nancy , Badeau Roland
Published: May 2008

The use of the non-negative matrix factorization (NMF) as a decomposition technique has dramatically grown in various signal processing applications over the last years. Its computation, based on the iterative minimization of a cost function, relies on several choices, among which the distance involved in the cost function itself but also the initialization of the algorithm. These choices are all the more crucial as the usual algorithms, iterative, only ensure convergence to a local minimum. In this work, we compare three typical distances in the NMF problem (namely Euclidian, Kullback-Leibler divergence and Itakura-Saito distance) and their combination with different initializations, in an audio context: decomposition of the time-frequency representation for the transcription of polyphonic music. Both the existence of global and local minima, and the efficiency of transcription are examined. Moreover, NMF update rules can be formulated in a unified framework for the three aforementioned cost functions. This formulation allows figuring out new NMF algorithms which could address the local minima question.
Sound feature extraction to distinguish between a grand and an upright piano
Authors: Plitsis Grigorios
Published: May 2008

The sound of a grand piano differs from that of an upright piano. In order to find what characterizes the produced sound, an instrument recognition system capable of producing a model of the sound features should be created. Feature extraction can be performed with the use of the Mel frequency cepstral coefficients (MFCCs). This method is useful as it approximates the mechanism of human hearing. Statistical modeling can be further applied using the Gaussian mixture model (GMM) so as to train the system. In order to decide whether the under test instrument is a grand or an upright piano the log-likelihood should be calculated. This study could assist in the identification of the parameters defining the sound of a grand and an upright piano.
Sparse representations of audio: from source separation to wavefield compressed sensing
Authors: Gribonval Remi
Published: May 2008

Sparse signal representations, which are at the heart of today's coding standards (JPEG, MPEG, MP3), are known to have had a substantial impact in signal compression. Their principle is to represent high-dimensional data by a combination of a few elementary building blocks, called atoms, chosen from a large collection called a dictionary. Over the last five years, theoretical advances in sparse representations have highlighted their potential to impact all fundamental areas of signal processing. We will discuss some current and emerging applications of sparse models in musical sound processing including: signal acquisition (Compressed Sensing - sampling wave fields at a dramatically reduced rate) and signal manipulation (e.g., source separation and enhancement for digital remastering). We will conclude by discussing the new algorithmic and modeling challenges raised by these approaches.
Towards a hierarchically sparse model for audio signals
Authors: Daudet Laurent
Published: May 2008

In this paper we discuss a major issue that arises when building sparse atomic models for music signals: in which space (/ dictionary) should we represent the signals? Having extremely redundant dictionaries is very informative for the locally most important atoms, but is irrelevant for the detail atoms that represent residual signals. Also, what are the advantages of dictionaries composed of learned atoms (which brings the issue of representativeness) compared to generic dictionaries? We here advocate for non-fixed dictionaries, with a multi-layered hierarchical decomposition: the first layer roughly describes the signal, in an extremely redundant, signal-tailored, structured dictionary. This layer is also very sparse, most of the information being carried by the atoms' parameters, similarly to parametric representations. Subsequent layers give more and more details, increasing the data amount while reducing overcompleteness and structural model constraints. These techniques have obvious applications for audio coding, but are also useful for scalable music data mining. This research is supported by the French ANR (DESAM project).
Efficient coding of a xylophone sound using spikogram nonredundent coding
Authors: Bader Rolf
Published: May 2008

Sensory systems try to use the incoming data most efficiently. Studies of Lewicki et al. lately showed, that a representation of a spike train just representing the sound and not having any redundancy is how the auditory system of the cat represents incoming sounds. To compare this theory with musical instruments, a xylophone sound was analyzed in terms of a spikogram. Here, gammatones of a 64 channel filterbank with different attack and decay values are superposed in a way to reconstruct the original sound. Only those gammatones were used which are needed to result in the sound used as input and so no redundancy is present in the analysis of the sound. It was found, that the most reasonable fit of the gammatone shape with the empirical data indeed made the representation most efficient and so the xylophone sound is most easily represented by the auditory system. Although more analysis are needed here, musical instruments could show up to be built in a way to fit a most efficient coding by listeners and so fulfill a middle-of-the-road rule of not too much and not too few information so that listeners are interested in but not overtaxed by the sounds.
Music and speech signal processing using harmonic-temporal clustering
Authors: Le Roux Jonathan , Kameoka Hirokazu , Ono Nobutaka , De Cheveigne Alain , Sagayama Shigeki
Published: May 2008

We present here the principle of the recently introduced harmonic-temporal clustering (HTC) framework and its applications in both music and speech signal processing. HTC relies on a precise parametric description of the harmonic parts of the power spectrum through constrained Gaussian mixture models. The model parameters of all the elements of the acoustical scene are estimated jointly by an unsupervised 2D time-frequency clustering of the observed power density. HTC is effective for multi-pitch analysis of music signals and F0 estimation of single and multiple speaker speech signals in various noisy environments. It also enables to perform extra processing of monaural music and speech signals, such as isolation or cancellation of a particular part, noise reduction and source separation.
Comparison of the sound of a grand and an upright piano using wavelets
Authors: Plitsis Grigorios
Published: May 2008

Wavelet analysis is useful for extracting patterns and thus analyzing signals. Although the Fourier analysis can reveal different features of a signal, it is less appropriate for describing transient phenomena and sudden sound changes. As a result, Fourier-based music reconstruction cannot exactly imitate the physical sound, as it is not possible to know at the same time a specific frequency as well as the time of occurrence of this frequency. Wavelet analysis is capable of highlighting different attributes of a signal. Different types of wavelets are thus used in the present study in order to compare the sound produced by a grand piano with that produced by an upright piano.
Characterizing the sound of an African thumb piano (kalimba)
Authors: Chapman David M.f.
Published: May 2008

The kalimba is an African percussion instrument whose notes are generated by vibrating metal tines of various lengths attached to sound board or sound box. Unlike a vibrating string or organ pipe, the overtone structure is anharmonic, that is, the overtone frequencies (which determine sound quality) are not simple integer multiples of the fundamental frequency (which determines pitch). The ratio of the first overtone to the fundamental is in the range 5.3-5.9, depending on the tine geometry. The vibrating tines are modeled as a clamped-supported-free beam and the observed overtone structure is shown to be in accordance with this model. Audio examples will be provided.
Using the soundscape approach to develop a public space in Berlin - measurement and calculation
Authors: Volz Rudi , Jakob Andre , Schulte-Fortkamp Brigitte
Published: May 2008

In this contribution the Soundscape Project “Nauener Platz” in Berlin is subject to different measurement- and calculation methods to develop acoustical indicators and parameters into a database describing urban and other outdoor living areas with respect to physical conditions and their relevance for life. The “Nauener Platz” is carried out to rebuilt a difficult open space into a space which is dominated by social freedom. To obtain the physical quantities sound pressure levels in 1/3-octave bands were measured and artificial head recordings were taken to describe the current state. Combined with calculations using noise prediction software it was possible to verify the sound propagation data outside according to the measurements and allow predictions about planned arrangements. First estimations of these measurements and calculations will be presented. The Soundscape Project is a module of the Project “Nauener Platz - remodelling for young and old”. This project is in the framework of the research program “Experimental Housing and Urban Development (ExWoSt)” of the “Federal Ministry of Transport, Building, and Urban Affairs (BMVBS)” by the “Federal Office for Building and Regional Planning (BBR)”. It is related to the fields of research (ExWoSt) concerned with “Innovation of Urban Neighbourhoods for Families and the Elderly”. The project executing organization is the Regional Office Berlin-Mitte.
Are perceived soundscapes within urban parks restorative
Authors: Payne Sarah R.
Published: May 2008

The perceived quality of urban park soundscapes is starting to be explored, and attention restoration research has shown which environments are generally restorative. Yet the effect of perceived soundscapes on individuals' restorative experiences is hardly known. Natural environments, in general, provide restoration for people, including recovery from attentional fatigue and enabling reflection. Therefore the visually “natural” environment of urban parks provides a useful setting to explore the role of varying soundscapes in restoration. Four hundred park users within Sheffield, UK, were surveyed as they left two urban parks. Data were collected on aspects of their park visit, along with measures of their current perceived restoration. Participants' perceived soundscapes were described by the amount of time they heard certain sound types in the park, and the volume at which they heard them. Sound levels [LAeq, dB(A)] within the parks were also monitored on a number of days to provide contextual information. Results of the study will be discussed along with the importance of soundscape quality and individuals' restorative experiences in helping to provide a productive and positive quality of urban life.
Soundscape characterization in selected areas of Central London
Authors: Memoli Gianluca , Bloomfield Alan , Dixon Max
Published: May 2008

The Mayor of London's Ambient Noise Strategy 'Sounder City' is the first UK public policy document to promote, not just noise reduction, but positive soundscape management. For its prescriptions to be put into full effect, psychoacoustic methods are needed to characterize existing areas where action may be needed to counteract existing noise pollution. To this aim, the soundscape characterization of two different areas in Central London will be presented in this work, where the two selected parks have in common the presence of a heavily trafficked road nearby. The acoustical experience of passers-by will be mapped using an indicator related to the time history of sound energy, related in previous studies to people's perceptions. Comparison with the same description performed by classical psychoacoustic parameters and perspectives for innovative, positive soundscape based actions will be discussed.