bluuebunny/crossref_metadata_2025 huggingface dataset:
The Second Princeton Consensus on Sexual Dysfunction and Cardiac Risk: New Guidelines for Sexual Medicine
Authors: Jackson Graham , Rosen Raymond C. , Kloner Robert A. , Kostis John B.
Published: January 2006

Introduction

Erectile dysfunction (ED) is a highly prevalent disorder associated with a significant burden of illness. The prevalence and incidence of ED are strongly age-related, affecting more than half of men >60 years. The first Princeton Consensus Conference (Princeton I) in 1999 developed guidelines for safe management of cardiac patients regarding sexual activity and the treatment of ED.

Aim

The second conference (Princeton II) was convened to update the recommendations based on the expanding knowledge base and new treatments available. This article reviews and expands on the Princeton II guidelines to address sexual dysfunction and cardiac risk.

Methods

A consensus panel of experts reviewed recent multinational studies in safety and drug interaction data for three phosphodiesterase type 5 (PDE5) inhibitors (sildenafil, tadalafil, vardenafil), with emphasis on the safety of these agents in men with ED and concomitant cardiovascular disease.

Results

Erectile dysfunction is an early symptom or harbinger of cardiovascular disease, due to the common risk factors and pathophysiology mediated through endothelial dysfunction. Major comorbidities include diabetes, hypertension, hyperlipidemia and heart disease. Any asymptomatic man who presents with ED that does not have an obvious cause (e.g., trauma) should be screened for vascular disease and have blood glucose, lipids, and blood pressure measurements. Ideally, all patients at risk but asymptomatic for coronary disease should undergo an elective exercise electrocardiogram to facilitate risk stratification. Lifestyle intervention in ED, specifically weight loss and increased physical activity, particularly in patients with ED and concomitant cardiovascular disease, is literature-supported.

Conclusions

The recognition of ED as a warning sign of silent vascular disease has led to the concept that a man with ED and no cardiac symptoms is a cardiac (or vascular) patient until proven otherwise. Men with ED and other cardiovascular risk factors (e.g., obesity, sedentary lifestyle) should be counseled in lifestyle modification.
Theoretical Accuracy of Model-Based Shape Matching for Measuring Natural Knee Kinematics with Single-Plane Fluoroscopy
Authors: Fregly Benjamin J. , Rahman Haseeb A. , Banks Scott A.
Published: January 2006

Quantification of knee motion under dynamic, in vivo loaded conditions is necessary to understand how knee kinematics influence joint injury, disease, and rehabilitation. Though recent studies have measured three-dimensional knee kinematics by matching geometric bone models to single-plane fluoroscopic images, factors limiting the accuracy of this approach have not been thoroughly investigated. This study used a three-step computational approach to evaluate theoretical accuracy limitations due to the shape matching process alone. First, cortical bone models of the femur, tibia/fibula, and patella were created from CT data. Next, synthetic (i.e., computer generated) fluoroscopic images were created by ray tracing the bone models in known poses. Finally, an automated matching algorithm utilizing edge detection methods was developed to align flat-shaded bone models to the synthetic images. Accuracy of the recovered pose parameters was assessed in terms of measurement bias and precision. Under these ideal conditions where other sources of error were eliminated, tibiofemoral poses were within 2mm for sagittal plane translations and 1.5deg for all rotations while patellofemoral poses were within 2mm and 3deg. However, statistically significant bias was found in most relative pose parameters. Bias disappeared and precision improved by a factor of two when the synthetic images were regenerated using flat shading (i.e., sharp bone edges) instead of ray tracing (i.e., attenuated bone edges). Analysis of absolute pose parameter errors revealed that the automated matching algorithm systematically pushed the flat-shaded bone models too far into the image plane to match the attenuated edges of the synthetic ray-traced images. These results suggest that biased edge detection is the primary factor limiting the theoretical accuracy of this single-plane shape matching procedure.
Fluid-Structure Interaction Effects on Sac-Blood Pressure and Wall
Stress in a Stented Aneurysm
Authors: Li Z. , Kleinstreuer C.
Published: January 2006

An aneurysm is a local artery ballooning greater than 50% of its nominal diameter with a risk of sudden rupture. Minimally invasive repair can be achieved by inserting surgically a stent-graft, called an endovascular graft (EVG), which is either straight tubular, curved tubular, or bifurcating. However, post-procedural complications may arise because of elevated stagnant blood pressure in the cavity, i.e., the sac formed by the EVG and the weakened aneurysm wall. In order to investigate the underlying mechanisms leading to elevated sac-pressures and hence to potentially dangerous wall stress levels and aneurysm rupture, a transient 3-D stented abdominal aortic aneurysm model and a coupled fluid-structure interaction solver were employed. Simulation results indicate that, even without the presence of endoleaks (blood flowing into the cavity), elevated sac pressure can occur due to complex fluid-structure interactions between the luminal blood flow, EVG wall, intra-sac stagnant blood, including an intra-luminal thrombus, and the aneurysm wall. Nevertheless, the impact of sac-blood volume changes due to leakage on the sac pressure and aneurysm wall stress was analyzed as well. While blood flow conditions, EVG and aneurysm geometries as well as wall mechanical properties play important roles in both sac pressure and wall stress generation, it is always the maximum wall stress that is one of the most critical parameters in aneurysm rupture prediction. All simulation results are in agreement with experimental data and clinical observations.
Elastic Model for Crimped Collagen Fibrils
Authors: Freed Alan D. , Doehring Todd C.
Published: January 2006

A physiologic constitutive expression is presented in algorithmic format for the nonlinear elastic response of wavy collagen fibrils found in soft connective tissues. The model is based on the observation that crimped fibrils in a fascicle have a three-dimensional structure at the micron scale that we approximate as a helical spring. The symmetry of this wave form allows the force/displacement relationship derived from Castigliano’s theorem to be solved in closed form: all integrals become analytic. Model predictions are in good agreement with experimental observations for mitral-valve chordæ tendineæ.
Heat-Induced Changes in the Finite Strain Viscoelastic Behavior of a Collaagenous Tissue
Authors: Baek S. , Wells P. B. , Rajagopal K. R. , Humphrey J. D.
Published: January 2006

Supra-physiological temperatures are increasingly being used to treat many different soft tissue diseases and injuries. To identify improved clinical treatments, however, there is a need for better information on the effect of the mechanics on the thermal damage process as well as the effect of the incurred damage on the subsequent mechanical properties. In this paper, we report the first biaxial data on the stress relaxation behavior of a collagenous tissue before and after thermal damage. Based on a two-dimensional finite strain viscoelastic model, which incorporates an exponential elastic response, it is shown that the thermal damage can significantly decrease the characteristic time for stress relaxation and the stress residual.
Spatial release from informational masking in speech recognition
Authors: Freyman Richard L. , Balakrishnan Uma , Helfer Karen S.
Published: January 2006

Three experiments were conducted to determine the extent to which perceived separation of speech and interference improves speech recognition in the free field. Target speech stimuli were 320 grammatically correct but nonmeaningful sentences spoken by a female talker. In the first experiment the interference was a recording of either one or two female talkers reciting a continuous stream of similar nonmeaningful sentences. The target talker was always presented from a loudspeaker directly in front (0°). The interference was either presented from the front loudspeaker (the F-F condition) or from both a right loudspeaker (60°) and the front loudspeaker, with the right leading the front by 4 ms (the F-RF condition). Due to the precedence effect, the interference in the F-RF condition was perceived to be well to the right, while the target talker was heard from the front. For both the single-talker and two-talker interference, there was a sizable improvement in speech recognition in the F-RF condition compared with the F-F condition. However, a second experiment showed that there was no F-RF advantage when the interference was noise modulated by the single- or multi-channel envelope of the two-talker masker. Results of the third experiment indicated that the advantage of perceived separation is not limited to conditions where the interfering speech is understandable.
Dynamic consequences of differences in male and female vocal tract dimensions
Authors: Simpson Adrian P.
Published: January 2006

Phonetic differences between male and female speakers are generally considered in terms of the static acoustic and perceptual consequences of different articulatory dimensions. This article investigates the dynamic acoustic and articulatory implications of differences in mean male and female vocal tract dimensions. The temporal acoustic consequences of time-varying twin-tube resonators of different dimensions are explored, and the possible implications for human speech production are considered. Empirical support for the theoretical predictions is sought by investigating the kinematic and acoustic patterns in diphthong productions from 26 female and 22 male speakers in the University of Wisconsin X-ray Microbeam Speech Production Database. Aside from expected acoustic differences, the shape of male and female formant tracks plotted in Bark space is found to be very similar. Male and female patterns of tongue movement, however, are found to be very dissimilar. The mean male diphthong, defined by the tracks of four midsagittal pellets, is characterized by greater pellet excursions, higher pellet speed, and consistently larger dorso-palatal strictures than its female counterpart. The empirical findings suggest that gender-specific dynamic behavior could be an important factor in accounting for nonuniform vowel system differences, but at the same time having more wide-ranging implications for transitional phenomena and undershoot.
Evaluation of speech intelligibility with the coordinate response measure
Authors: Brungart Douglas S.
Published: January 2006

The sentences in the coordinate response measure (CRM) corpus described in a recent letter to this journal [Bolia et al., J. Acoust. Soc. Am. 107, 1065–1066 (2000)] have been used to measure speech intelligibility as a function of signal-to-noise ratio with a speech-spectrum-shaped noise masker. The data from this experiment, along with those of an earlier experiment comparing intelligibility with the CRM and the well-known modified rhyme test (MRT), have also been used to estimate performance with the CRM as a function of the articulation index (AI) for a variety of different masking signals. The results provide a normative evaluation of the CRM for potential users of the CRM corpus, and can be used to compare the CRM with other measures of speech intelligibility.
Acoustic-phonetic features for the automatic classification of fricatives
Authors: Abdelatty Ali Ahmed M. , Van der Spiegel Jan , Mueller Paul
Published: January 2006

In this article, the acoustic-phonetic characteristics of the American English fricative consonants are investigated from the automatic classification standpoint. The features studied in the literature are evaluated and new features are proposed. To test the value of the extracted features, a statistically guided, knowledge-based, acoustic-phonetic system for the automatic classification of fricatives in speaker-independent continuous speech is proposed. The system uses an auditory-based front-end processing system and incorporates new algorithms for the extraction and manipulation of the acoustic-phonetic features that proved to be rich in their information content. Classification experiments are performed using hard-decision algorithms on fricatives extracted from the TIMIT database continuous speech of 60 speakers (not used in the design/training process) from seven different dialects of American English. An accuracy of 93% is obtained for voicing detection, 91% for place of articulation detection, and 87% for the overall classification of fricatives.
Adaptive time-reversal mirror
Authors: Kim J. S. , Song H. C. , Kuperman W. A.
Published: January 2006

The time-reversal mirror uses the received signal from a probe source to refocus the signal at the probe source location by backpropagating the time-reversed version of the received signal. In this study, an adaptive method is described to steer a null to an arbitrary position in a waveguide while maintaining a distortionless response at the probe source location. As an application, selective focusing in free space is demonstrated.
The relationship between spectral characteristics and perceived hypernasality in children
Authors: Kataoka Ryuta , Warren Donald W. , Zajac David J. , Mayo Robert , Lutz Richard W.
Published: January 2006

The purpose of this study was to quantify perceived hypernasality in children. One-third octave spectra of the isolated vowel [i] were obtained from 32 children with cleft palate and 5 children without cleft palate. Four experienced listeners rated the severity of hypernasality of the 37 speech samples using a 6-point equal-appearing interval scale. When the average 1/3-octave spectra from the hypernasal group and the normal resonance group were compared, spectral characteristics of hypernasality were identified as increased amplitudes between F1 and F2 and decreased amplitudes in the region of F2. Based on the findings of the children’s speech, 36 speech samples with manipulated spectral characteristics were used to minimize the influences of voice source characteristics on perceived hypernasality. Multiple regression analysis revealed a high correlation (R=0.84) between the amplitudes of 1/3-octave bands (1 k, 1.6 k, and 2.5 kHz) and the perceptual ratings. Increased amplitudes of bands between F1 and F2 (1 k, 1.6 kHz) and decreased amplitude of the band of F2 (2.5 kHz) was associated with an increasing perceived hypernasality. These results suggest that the amplitudes of the three 1/3-octave bands are appropriate acoustic parameters to quantify hypernasality in the isolated vowel [i].
Excitation of T-phases by seafloor scattering
Authors: de Groot-Hedlin Catherine D. , Orcutt John A.
Published: January 2006

T-phases excited by suboceanic earthquakes are classified into two types: abyssal phases which are excited near the earthquake epicenter at seafloor depths far below the SOFAR velocity channel, and slope T-phases which are excited at continental, or ocean island slopes and ridges at distances up to several hundreds of kilometers from the epicenter. In this article, it is demonstrated that approximate time–frequency characteristics of both classes of T-phase can be synthesized under the assumption that T-phases are excited by scattering from a rough seafloor. Seafloor scattering at shallow depths preferentially excites low order acoustic modes that propagate efficiently within the ocean sound channel minimum. At greater depths, scattering excites higher order modes which interact weakly with the seafloor along much of the propagation path. Using known variations in near-source bathymetry, T-phase envelopes are synthesized at several frequencies for several events south of the Fox Islands that excited both types of T-phase. The synthesized T-phases reproduce the main time vs frequency features of each type of arrival; a higher frequency, nearly symmetric arrival excited near the epicenter and a longer duration, lower frequency arrival excited near the continental shelf, with a peak amplitude at about 5 Hz.
Atmospheric scattering for varying degrees of saturation and turbulent intermittency
Authors: Norris David E. , Wilson D. Keith , Thomson Dennis W.
Published: January 2006

Atmospheric turbulence is inherently inhomogeneous and intermittent. Short periods of high activity are embedded in longer periods of relative calm. Local spatial and temporal changes in sound speed associated with this intermittency increase the likelihood of measuring large values of scattered acoustic signals. Previous work successfully predicted the probability density functions (pdf’s) of fully saturated, scattered signals measured within an acoustic shadow zone [Wilson et al., J. Acoust. Soc. Am. 99, 3393–3400 (1996)]. The more general case of incompletely saturated scattering is considered in this paper; using the Rice–Nagakami distribution a theory is developed. The predicted intensity pdf has two free parameters: one to describe the degree of intermittency and a second for the degree of saturation. For validation purposes, outdoor propagation measurements were made over a flat, hard ground at ranges of 146–283 m and at frequencies of 50–540 Hz. The saturation parameter was determined from the acoustic data and also estimated from the turbulence conditions. The degree of saturation increased with frequency, and measured intensity pdf’s were found to be in excellent agreement with the theory.
Effects of delayed auditory feedback (DAF) on the pitch-shift reflex
Authors: Hain Timothy C. , Burnett Theresa A. , Larson Charles R. , Kiran Swathi
Published: January 2006

Changes in voice pitch auditory feedback to vocalizing subjects elicit compensatory changes in voice fundamental frequency (F0). The neural mechanisms responsible for this behavior involve the auditory and vocal-motor systems, collectively known as the audio-vocal system. Previous work [Burnett et al., J. Acoust. Soc. Am. 103, 3153–3161 (1998); Hain et al., Exp. Brain Res. 130, 133–141 (2000); Larson et al., J. Acoust. Soc. Am. 107, 559–564 (2000)] indicated that this system operates using negative feedback to cancel out low-level errors in voice F0 output. By introducing delays in the auditory feedback pathway, we hoped to transiently “open” the feedback loop and learn which components of the response are most closely related to the timing of the auditory feedback signal. Subjects were presented with pitch-shift stimuli that were paired with a delay of 0, 50, 100, 200, 300, or 500 ms. Delayed auditory feedback did not affect voice F0 response latency or magnitude, but it delayed the timing of later parts of the response. As a further test of the audio-vocal control system, a second experiment was conducted in which delays of 100, 200, or 300 ms were combined with stimuli having onset velocities of 1000 or 330 cents/s. Results confirmed earlier reports that the system is sensitive to velocity of stimulus onset. A simple feedback model reproduced most features of both experiments. These results strongly support previous suggestions that the audio-vocal system monitors auditory feedback and, through closed-loop negative feedback incorporating a delay, adjusts voice F0 so as to cancel unintentional small magnitude fluctuations in F0.
Frequency glides in click responses of the basilar membrane and auditory nerve: Their scaling behavior and origin in traveling-wave dispersion
Authors: Shera Christopher A.
Published: January 2006

Frequency modulations (or glides), reported in impulse responses of both the auditory nerve and the basilar membrane, represent a change over time in the instantaneous frequency of oscillation of the response waveform. Although the near invariance of glides with stimulus intensity indicates that they are not the consequence of nonlinear or active processes in the inner ear, their origin has remained otherwise obscure. This paper combines theory with experimental data to explore the basic phenomenology of glides. When expressed in natural dimensionless form, glides are shown to have a universal form nearly independent of cochlear location for characteristic frequencies (CFs) above approximately 1.5 kHz (the “scaling region”). In the apex of the cochlea, by contrast, glides appear to depend strongly on CF. In the scaling region, instantaneous-frequency trajectories are shown to be approximately equal to the “inverse group delays” of basilar-membrane transfer functions measured at the same locations. The inverse group delay, obtained by functionally inverting the transfer-function group-delay-versus-frequency curve, specifies the frequency component of a broadband stimulus expected to be driving the cochlear partition at the measurement point as a function of time. The approximate empirical equality of the two functions indicates that glides are closely related to cochlear traveling-wave dispersion and suggests that they originate primarily through the time dependence of the effective driving pressure force at the measurement location. Calculations in a one-dimensional cochlear model based on solution to the inverse problem in squirrel monkey [Zweig, J. Acoust. Soc. Am. 89, 1229–1254 (1991)] support this conclusion. In contrast to previous models for glides, which locate their origin in the differential build-up and decay of multiple micromechanical resonances local to each radial cross section of the organ of Corti, the model presented here identifies glides as the global consequence of the dispersive character of wave propagation in the cochlea.
Vector potential in spherical polar coordinates
Authors: Ahmad F. , Ahsan-ul-Haq
Published: January 2006

We comment on a recent paper [J. Acoust. Soc. Am. 104, 2836–2844 (1998)] and point out certain errors in the mathematical formulation of the problem.
The use of impedance matching capillaries for reducing resonance in rosette infrasonic spatial filters
Authors: Hedlin Michael A. H. , Alcoverro Benoit
Published: January 2006

Rosette spatial filters are used at International Monitoring System infrasound array sites to reduce noise due to atmospheric turbulence. A rosette filter consists of several clusters, or rosettes, of low-impedance inlets. Acoustic energy entering each rosette of inlets is summed, acoustically, at a secondary summing manifold. Acoustic energy from the secondary manifolds are summed acoustically at a primary summing manifold before entering the microbarometer. Although rosette filters have been found to be effective at reducing infrasonic noise across a broad frequency band, resonance inside the filters reduces the effectiveness of the filters at high frequencies. This paper presents theoretical and observational evidence that the resonance inside these filters that is seen below 10 Hz is due to reflections occuring at impedance discontinuities at the primary and secondary summing manifolds. Resonance involving reflections at the inlets amplifies noise levels at frequencies above 10 Hz. This paper further reports results from theoretical and observational tests of impedance matching capillaries for removing the resonance problem. Almost total removal of resonant energy below 5 Hz was found by placing impedance matching capillaries adjacent to the secondary summing manifolds in the pipes leading to the primary summing manifold and the microbarometer. Theory and recorded data indicate that capillaries with resistance equal to the characteristic impedance of the pipe connecting the secondary and primary summing manifolds suppresses resonance but does not degrade the reception of acoustic signals. Capillaries at the inlets can be used to remove resonant energy at higher frequencies but are found to be less effective due to the high frequency of this energy outside the frequency band of interest.
Consonant recognition and the articulation index
Authors: Allen Jont B.
Published: January 2006

The purpose of this paper is to provide insight into how speech is processed by the auditory system, by quantifying the nature of nonsense speech sound confusions. (1) The Miller and Nicely [J. Acoust. Soc. Am. 27(2), 338–352 (1955)] confusion matrix (CM) data are analyzed by plotting the CM elements Si,j(SNR) as a function of the signal-to-noise ratio (SNR). This allows for the robust clustering of perceptual feature (event) groups, not robustly defined by a single CM table, where clusters depend on the sound order. (2) The SNR is then re-expressed as an articulation index (AI), and used as the independent variable. The normalized log scores log(1−Si,i(AI)) and log(Si,j(AI)), j≠i, then become linear functions of AI, on log-error versus AI plots. This linear dependence may be interpreted as an extension of the band-independence model of Fletcher. (3) The model formula for the average score for the finite-alphabet case Pc(AI,H)=∑i=1NSi,i/N is then modified to include the effect of entropy H. Due to the grouping of sounds with increased SNR (and AI), the sound-group entropy Hg plays a key role in this performance measure. (4) A parametric model for the confusions Si,j(AI,Hg) is then described, which characterizes the confusions between competing sounds within a group.
Lamb mode conversion at edges. A hybrid boundary element–finite-element solution
Authors: Galán José M. , Abascal Ramón
Published: January 2006

Two general and flexible numerical techniques based on the finite-element and boundary element methods developed by the authors in a previous paper are applied to study Lamb wave propagation in multilayered plates and Lamb mode conversion at free edges for frequencies beyond the first cutoff frequency. Both techniques are supported by a meshing criterion which guarantees the accuracy of the results when a condition is fulfilled. A finite-element formulation is directly applicable to study Lamb wave propagation and reflection by simple obstacles such as a flat edge. In order to tackle Lamb wave diffraction problems by defects with more complex geometries, a hybrid boundary element–finite-element formulation is used. This technique provides a major improvement with respect to the only previous boundary element application on Lamb waves: the connecting boundary might be placed as close to the reflector as desired, reducing greatly the requirement on mesh size. Two main application problems on practical metallic plates are studied and compared with reported numerical, theoretical, and experimental results: (1) Lamb wave propagation in degraded titanium diffusion bonds, and (2) Lamb mode conversion at inclined or perpendicular free edges of steel plates for frequencies beyond the first cutoff frequency.
Measurement of the depth-dependent resonance of water-loaded human lungs
Authors: Martin J. S. , Rogers P. H. , Cudahy E. A.
Published: January 2006

An experiment was conducted to determine the response of the human lung to water-borne sound in the range of 20 to 500 Hz. A small pool inside a hyperbaric chamber was used to simulate four ambient pressure conditions spanning the range of recreational diving depths. Ten subjects were tested on two occasions each using three separate measures to evaluate the response of the subjects’ lungs. With some notable exceptions, results were consistent between subjects and between measures. These indicate that human lungs can be reasonably modeled as a lumped single-degree-of-freedom system over the lower portion of the band of interest. Here, the surrounding fluid provides the dominant mass and the dominant stiffness is provided by the entrapped air with a small additional contribution from tissue elasticity. Measured resonances increase with the square root of ambient pressure from an average of 40 Hz with a quality factor of 1.8 at near-surface pressure to 73 Hz with a quality factor of 2.6 at an equivalent depth of 36.4 m. There is evidence of other resonances within or near the band of interest that may be attributable to nonvolumetric chest/lung modes, Helmholtz resonance, and/or resonance of gastrointestinal bubbles.
Phase speed and attenuation in bubbly liquids inferred from impedance measurements near the individual bubble resonance frequency
Authors: Wilson Preston S. , Roy Ronald A. , Carey William M.
Published: January 2006

In the ocean, natural and artificial processes generate clouds of bubbles that scatter and attenuate sound. Measurements have shown that at the individual bubble resonance frequency, sound propagation in this medium is highly attenuated and dispersive. The existing theory to explain this behavior is deemed adequate away from resonance. However, due to excessive attenuation near resonance, little experimental data exists for a comparison with model predictions. An impedance tube was developed specifically for exploring this regime. The effective medium phase speed and attenuation were inferred from measurements of the surface impedance of a layer of bubbly liquid composed of air bubbles and distilled water, for void fractions from 6.2×10−5 to 5.4×10−4 and bubble sizes centered around 0.62 mm in radius. Improved measurement speed, accuracy, and precision is possible with the new instrument, and both instantaneous and time-averaged measurements were obtained. The phase speed and attenuation at resonance was observed to be sensitive to the bubble population statistics and agreed with an existing model [J. Acoust. Soc. Am. 85, 732–746 (1989)], within the uncertainty of the bubble population parameters. Agreement between the model and the data reported here is better than for the data that was available when the model was originally published.
Defect imaging with guided waves in a pipe
Authors: Hayashi Takahiro , Murase Morimasa
Published: January 2006

Guided wave techniques are expected to become an effective means for rapid, long-range inspection of pipes. Such techniques still have many practical difficulties in application, however, due to the complex characteristics of guided waves such as dispersion and their multimodal nature. A defect imaging technique is developed in this study to overcome the complexities of guided wave inspection. Received signals are separated into single-mode waveforms with a mode extraction technique and then spatial waveforms on the pipe surface at an arbitrary time are reconstructed. The predicted waveforms can provide a defect image at the moment when an incident wave arrives at a defect region, which is based on a time-reversal technique. This defect imaging technique is experimentally verified using eight signals detected at eight different circumferential positions. Images of artificial defects are obtained with one-hole and two-hole test pipes, and increasing the frequency of incident waves increases the resolution of the images. Holes and pipe ends are recognizable in the images, but the reconstructed images contain some errors in the area behind the defects where guided waves do not propagate or do not reflect back to the receiving transducers.
Geoacoustic inversion in time domain using ship of opportunity noise recorded on a horizontal towed array
Authors: Park Cheolsoo , Seong Woojae , Gerstoft Peter
Published: January 2006

A time domain geoacoustic inversion method using ship noise received on a towed horizontal array is presented. The received signal, containing ship noise as a source of opportunity, is time-reversed and then back-propagated to the vicinity of the ship. The back-propagated signal is correlated with the modeled signal which is expected to peak at the ship’s location in case of a good match for the environment. This match is utilized for the geoacoustic parameter inversion. The objective function for this optimization problem is thus defined as the normalized power focused in an area around the source position, using a matched impulse response filter. A hybrid use of global and local search algorithms, i.e., GA and Powell’s method is applied to the optimization problem. Applications of the proposed inversion method to MAPEX 2000 noise experiment conducted north of the island of Elba show promising results, and it is shown that the time domain inversion takes advantage of dominant frequencies of the source signature automatically.
Echolocation characteristics of free-swimming bottlenose dolphins during object detection and identification
Authors: Houser Dorian , Martin Stephen W. , Bauer Eric J. , Phillips Michael , Herrin Tim , Cross Matt , Vidal Andrea , Moore Patrick W.
Published: January 2006

A biosonar measurement tool (BMT) was created to investigate dolphin echolocation search strategies by recording echolocation clicks, returning echoes, and three-dimensional angular motion, velocity, and depth of free-swimming dolphins performing open-water target detections. Trial start and stop times, locations determined from a differential global positioning system (DGPS), and BMT motion and acoustic data were used to produce spatial and acoustic representations of the searches. Two dolphins (LUT, FLP) searched for targets lying on the seafloor of a bay environment while carrying the BMT. LUT searched rapidly (<10 s), produced few clicks, and varied click-peak frequency (20–120 kHz); FLP searched relatively slowly (tens of seconds) and produced many hundreds of clicks with stereotypical frequency-dependent energy distributions dominating from 30–60 kHz. Dolphins amplified target echo returns by either increasing the click source level or reducing distance to the target but without reducing source level. The distribution of echolocation click-peak frequencies suggested a bias in the dominant frequency components of clicks, possibly due to mechanical constraints of the click generator. Prior training and hearing loss accommodation potentially explain differences in the search strategies of the two dolphins.
Statistical properties of infant-directed versus adult-directed speech: Insights from speech recognition
Authors: Kirchhoff Katrin , Schimmel Steven
Published: January 2006

Previous studies have shown that infant-directed speech (‘motherese’) exhibits overemphasized acoustic properties which may facilitate the acquisition of phonetic categories by infant learners. It has been suggested that the use of infant-directed data for training automatic speech recognition systems might also enhance the automatic learning and discrimination of phonetic categories. This study investigates the properties of infant-directed vs. adult-directed speech from the point of view of the statistical pattern recognition paradigm underlying automatic speech recognition. Isolated-word speech recognizers were trained on adult-directed vs. infant-directed data sets and were tested on both matched and mismatched data. Results show that recognizers trained on infant-directed speech did not always exhibit better recognition performance; however, their relative loss in performance on mismatched data was significantly less severe than that of recognizers trained on adult-directed speech and presented with infant-directed test data. An analysis of the statistical distributions of a subset of phonetic classes in both data sets showed that this pattern is caused by larger class overlaps in infant-directed speech. This finding has implications for both automatic speech recognition and theories of infant speech perception.
The shift-invariant discrete wavelet transform and application to speech waveform analysis
Authors: Enders Jörg , Geng Weihua , Li Peijun , Frazier Michael W. , Scholl David J.
Published: January 2006

The discrete wavelet transform may be used as a signal-processing tool for visualization and analysis of nonstationary, time-sampled waveforms. The highly desirable property of shift invariance can be obtained at the cost of a moderate increase in computational complexity, and accepting a least-squares inverse (pseudoinverse) in place of a true inverse. A new algorithm for the pseudoinverse of the shift-invariant transform that is easier to implement in array-oriented scripting languages than existing algorithms is presented together with self-contained proofs. Representing only one of the many and varied potential applications, a recorded speech waveform illustrates the benefits of shift invariance with pseudoinvertibility. Visualization shows the glottal modulation of vowel formants and frication noise, revealing secondary glottal pulses and other waveform irregularities. Additionally, performing sound waveform editing operations (i.e., cutting and pasting sections) on the shift-invariant wavelet representation automatically produces quiet, click-free section boundaries in the resulting sound. The capabilities of this wavelet-domain editing technique are demonstrated by changing the rate of a recorded spoken word. Individual pitch periods are repeated to obtain a half-speed result, and alternate individual pitch periods are removed to obtain a double-speed result. The original pitch and formant frequencies are preserved. In informal listening tests, the results are clear and understandable.
Hearing relative phases for two harmonic components
Authors: Ives D. Timothy , Patterson Roy D. , Reimann H. Martin
Published: January 2006

There is a new wavelet model of basilar membrane motion which predicts that existing roex and gammatone filterbanks underestimate the interaction of harmonically related components in complex tones. This interaction appears as a modulation of the basilar membrane motion associated with a higher harmonic by the presence of a lower harmonic; the period of the modulation is that of the difference frequency, or the fundamental of the implied harmonic series. The modulation depth is largest for stimuli whose spectra have a similar energy distribution as natural sounds: a high frequency roll-off of about 12-dB per octave. The strength of the modulation frequency is dependent on the relative phase of the components, which predicts that listeners will be able to hear a relative phase change. A series of experiments were undertaken to determine the threshold for a change in the relative phase of the components. The results of the experiments show that a change in the relative phase is detectable for components that are generally believed to be resolved on the basilar membrane and therefore should not interact. [Work supported by the U.K. Medical Research Council (G9901257).]
Classification of dysarthric and non-impaired speech based on prosodic features
Authors: Kochanski Greg , Patel Rupal
Published: January 2006

Prosodic differences between dysarthric and healthy speakers were studied. Six acoustic properties that are plausibly more influenced by suprasegmental aspects of speech (e.g., emphasis) than the segmental details of the words were measured. The time course of these properties were analyzed over each utterance by fitting Legendre Polynomials. The resultant Legendre coefficients were then fed to linear- and quadratic-discriminant classifiers. All of the six properties were individually capable of distinguishing dysarthric speech from healthy speech. Based on one acoustic property measured over a single short sentence, we could correctly classify a speaker as healthy or dysarthric 55–75% of the time, depending on the acoustic property used. More complex classifiers that used all the acoustic properties correctly classified the speaker 97% of the time based on nine utterances. The strongest difference between normal and dysarthric speech was in loudness. Dysarthric speakers did not reliably produce the loudness patterns associated with stressed syllables. They also had a wider range in amplitude, greater voicing variability, smaller excursions of fundamental frequency, and less final lengthening compared to healthy speakers. The classification we demonstrated may be extended to a become a graduated measurement of severity, thereby contributing to diagnostics and intervention in dysarthria.
An acoustic microscope designed for observing the vocal fold tissue
Authors: Inoue Yojiro , Kakita Yuki , Hirano Minoru
Published: January 2006

This paper describes our newly designed scanning acoustic microscope (SAM). Our concern is to determine the mechanical properties of each histological component of the vocal folds in normal and varying pathological states. Generally speaking, the images obtained by means of an acoustic microscope not only present structure of the object to be investigated but also reflect its mechanical properties. Our present SAM has the following features. (1) The frequency of ultrasonic waves is variable between 100 and 200 MHz, causing the resolution between 5 and 10 μm. (2) Logarithmic and linear conversion of the image intensity are available. The image converted by logarithmic function can cover a wide range of mechanical properties. (3) Tilting mechanism is installed to the sample bed so as to adjust the angle of the specimen. (4) The images stored in the digital memory can be displayed on an ordinary video system. The structure and function of our new SAM system will be demonstrated together with some preliminary data of vocal fold tissue. [Work supported in part by Scientific Grant ♯57870103 by the Japanese Ministry of Education, Science and Culture.]
Comparing the relative advantages of pneumato- and electroacoustic sources for organ tone radiation in churches
Authors: Martin Daniel W.
Published: January 2006

The variety which exists within church architectural design, in liturgical forms of worship, in the relative location of church organs and the worshippers, and even in the structures (or lack thereof) which organ builders have provided in the immediate vicinity of the organ tone radiators, suggests that there is probably more than one aesthetically acceptable means for radiating organ tone into worship space. Yet some adherents to the traditional maintain that there is only one acceptable means for radiating organ tone, i.e., pneumatoacoustic. This analysis assumes (1) that equivalent room acoustics and tone source locations are provided for either pneumator- or electroacoustic tone radiators; and (2) that electrical input signals are provided to electroacoustic tone radiators which include the transient, spectral and modulation contributions to the tone by the traditional air stream interaction with a pipe resonator. What acoustical advantages and disadvantages remain for the two different types of tone radiation means?
How computer and electroacoustic technology are used to improve musical performance in church electronic organs
Authors: Kuhn Duane A.
Published: January 2006

Recent advances in technology enable the electronic organ to approximate closely the musical resources of the pipe organ while increasing the control and flexibility of those resources. To create a true ensemble of organ sound a patented multiple octave generator tuning system provides multiple frequency sources on a given note and variance in sources between different octaves of the same chromatic note, all under master clock control for tuning stability. A tone radiation system consisting of an electroacoustic pipe array with fifteen individual audio channels provides tone radiation characteristics similar to those of a group of air-blown flue pipes. The use of a microprocessor controlled combination action increases instrument reliability while reducing its cost. New control offered to the organist by this noise-free combination action includes pedal stop-to-manual division registration, visual identification of individual stops in the crescendo pedal sequence, and a new type of division cancel.
Acoustic analysis of cry of SIDS infants
Authors: Heinz John M. , Stark Rachel E. , Condino Rosemary , Hege Michele , Steinschneider Alfred
Published: January 2006

Spontaneous cry recordings were obtained for approximately 1700 infants born at the University of Maryland Hospital over a 212-year period. Where possible, recordings were obtained during both the first and fourth weeks of life. Of those infants recorded, four later died of SIDS. For one, recordings had been obtained during both the first and fourth weeks, for one only during the first week, for one only during the fourth week, and one only at two later times (9 and 14 weeks). Thirty-second samples of continuous, fully developed cry were selected for detailed analysis from each of the SIDS infants and from 50 age-matched controls. For each cry segment, measures of duration, intensity, and fundamental frequency were obtained and the presence or absence of a number of cry features was determined. Preliminary analysis of the data for the two SIDS infants recorded in week one indicates that a number of the measures group toward the tails of the distributions of these measures for the controls, while the data for the two SIDS infants recorded in week four do not show this pattern. Implications of these results and further findings will be discussed. [Work supported by NICHD and the Aaron Straus and Lillie Straus Foundation.]
An approach to telephone communication between deaf and hearing persons
Authors: Bernstein Jared , Becker R. , Bell D. , Murveit H. , Poza F. , Stevens G.
Published: January 2006

It may be possible for a deaf person and a hearing person to converse over the telephone using special equipment only at the deaf person's end of the connection. The deaf person drives a text-to-speech converter with an efficient keyboard system. The hearing person speaks sentences in a word-at-a-time fashion. The words are handled at the deaf person's end by a large vocabulary isolated-word recognition system that displays a sentence lattice (a sequence of sets of likely words for each word spoken). The deaf person then tries to find a sensible path through the sentence lattice. For such a system to be successful requires adequate performance in: (1) human text generation speed, (2) text-to-speech intelligibility, (3) human one-word-at-a-time speaking, (4) large vocabulary IWR, and (5) human disambiguation of sentence lattices. We report preliminary experimental results that bear on requirements (1), (2), (3), and (5); we outline an approach to (4), the implementation of which is simulated. Experimental studies of (1) and (5) are run on deaf subjects. [This material is based upon work supported by the National Science Foundation under Grant ECS-8023527.]
Identification of novel words and sentences using a tactile vocoder
Authors: Frost B. J. , Brooks P. L. , Gibson D. M. , Mason J. L.
Published: January 2006

The present experiments are part of an ongoing evaluation of a tactile vocoder that has been developed at Queen's University. The subject used in the experiments has normal hearing and had previously acquired a tactual vocabulary of 250 words. In all experiments the subject and reader sat in adjacent soundproof booths with a window providing visual contact when necessary. The first series of experiments examined the subject's ability to identify words that the subject had not received tactual experience with before. The subject was not aware of the possible words that might occur and a given word was only tested once. In the lipreading alone (LA) condition 39% of the words were identified correctly compared to 69% correct in the lipreading plus tactile vocoder (LV) condition. The ability of the subject to identify novel words with the tactile vocoder alone (VA) was surprising and encouraging. These results will be discussed in detail. Experiments testing the subject's ability to recognize open set sentences showed an increase in correct identification of over 100% when the LV condition was compared to the LA condition.