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Pitch circularity as found in Shepard tones was examined by using complex tones that had various degrees of exactness in their spectral periodicities on the logarithmic frequency dimension. This dimension was divided into periods of 1400 cents by tone components, and each period was subdivided into two parts of a fixed ratio of 700:700, 600:800, 550:850, 500:900, 450:950, 400:1000, or 0:1400. Subjects made paired comparison judgments for pitch. When the subdividing ratio was 0: 1400 or 400:1000, the subjects responded to the spectral periodicity of 1400 cents, and, when the ratio was 700:700 or 600:800, they responded to the periodicity of 700 cents. Some seemingly intermediate cases between these two extremes or some qualitatively different cases were obtained in the other conditions. As we have asserted before, the human ear appears to detect a global pitch movement when some tone components move in the same direction by similar degrees on the logarithmic frequency dimension.

Long-term studies of rabbit blood pressure require a reliable method for repeated blood pressure measurements. Ideally, this method would be simple, noninvasive, and accurate over the range of anticipated blood pressures. To facilitate our own studies of rabbit carotid artery graft patency, we have developed a technique for the indirect measurement of systolic blood pressure in the rabbit that utilizes a photoplethysmograph sensor placed distal to an inflatable air bladder positioned over the central ear artery. We have compared measurements obtained with this method to direct measurements of aortic pressure and found a linear correlation.

ProblemTo non-invasively measure the 2D curvature of human ear canal and produce the earmold by the non-invasive 3D ear impression.MethodsThe images of external ear were scanned by high-resolution computed tomography (HRCT). The resolution for each slice was 512⋉512 pixels. The pixel size was 0.188⋉0.188mm and the slice thickness was 0.625mm. The boundary between tympanic membrane and external auditory meatus was enhanced by image processing. Additionally, 3D model of ear canal was reconstructed by 2D images. The length and angle of first and second bends of canal were measured based on the 3D model. 2D curvature of first and second bends of canal was then computed by sine and cosine laws.ResultsThe volume of ear canal was 862.0 cubic mm. The angle and curvature of superior wall of first bend at axial view were 121.5 degrees and 0.0685; of inferior wall of first bend were 246 degrees and −0.1102; of superior wall of second bend were 227.8 degrees and −0.0332; of inferior wall of second bend were 143.1 deg...

The human ear is a complex biomechanical system and is divided by three parts: outer, middle and inner ear.

We address the problem of intra-subject registration for change detection. The goal is to separate stationary and changing subsets to be able to robustly perform rigid registration on the stationary subsets and thus improve the subsequent change detection. An iterative approach using a hybrid of parametric and non-parametric statistics is presented. The method uses non-parametric clustering and large scale hypothesis testing with estimation of the empirical null hypothesis. The method is successfully applied to 3D surface scans of human ear impressions containing true changes as well as data with synthesized changes. It is shown that the method improves registration and is capable of reducing the difference between registration using different norms.

A pervasive theme in the literature for the transient evoked otoacoustic emission (TEOAE) measured from the human ear canal has been one of the emission arising solely (or largely) from a single, place-fixed mechanism. Here TEOAEs are reported measured in the absence of significant stimulus contamination at stimulus onset, providing for the identification of a TEOAE response beginning within the time window that is typically removed by windowing. Contrary to previous studies, it was found that in humans, as has previously been found in guinea pig, the TEOAE appears to arise from two generation mechanisms, the relative contributions of these two mechanisms being time and stimulus-level dependent. The method of windowing the earliest part of the ear canal measurement to remove stimulus artifact removes part of the TEOAE i.e., much of the component arising from a nonlinear generation mechanism. This reconciliation of TEOAE origin is consistent with all OAEs in mammals arising in a stimulus-level dependent manner from two mechanisms of generation, one linear, one nonlinear, as suggested by Shera and Guinan [J. Acoust. Soc. Am. 105, 782-798 (1999)].

This paper presents the observation from SAR images of the dried Lop Nur Lake in Xinjiang of west China. Lop Nur Lake is one of the driest places in the world and finally lost its last drop of water in 1972. It is well known for its "human ear shape" feature in optical remote sensing images. Likewise, the "ear" feature is shown in synthetic aperture radar (SAR) images, and is even larger because of the penetration effect. The universal existence of lacustrine deposit with high water content and salinity are undetectable by previous remote sensing images in Lop Nur Lake. We have made some laboratory experiments about subsurface soils and developed an improved dielectric model for moist saline soil at microwave bands. A field trip was conducted from October 25 to November 8, 2006 to validate the image interpretation results. As an important indicator for environment degradation and climate change study in arid region, Lop Nur does need long-term and overall research to answer many scientific questions.

Valsalva's life as anatomist, physician, and surgeon of the late XVIIth century is surveyed. The second edition of the "Morgagni" version of Valsalva's Treatise on the Human Ear, published in 1741, is considered in relation to the work of his predecessors, the scientific milieu of his time, and his influence on the development of modern otology.

An improved analysis procedure has been applied to standing wave patterns measured previously [B. W. Lawton and M. R. Stinson, J. Acoust. Soc. Am. 79, 1003-1009 (1986)] in human ear canals. Revised acoustic energy reflection coefficients, at the eardrum, are obtained for 20 ears for frequencies between 3 and 13 kHz. The new analysis addresses anomalous features of the standing wave patterns, apparent at frequencies above 8 kHz, due primarily to the curvature of the ear canal. Much better agreement is now found, at these higher frequencies, between the theoretical form assumed for the standing wave patterns and the experimental data. The revised values of eardrum reflectance are somewhat smaller, especially for frequencies above 11 kHz. The reflectance rises from about 0.25 at 4 kHz up to 0.7 at 8 kHz, falls to a minimum of 0.5 at 11 kHz, then rises to 0.6 at 13 kHz. Considerable intersubject variability in the results is noted.

The cochleas of four human fetuses ranging 22–25 weeks gestation were studied by scanning electron microscopy (SEM) for the purpose of obtaining a better understanding of the nerve fiber arrangement in the human ear. After critical point drying, the specimens were dissected and the floor of the tunnel of Corti and the outer wall of Nuel's space were exposed for observation. Upper cochlear turns, especially the apical turn, seemed to be still immature. Observed nerve fibers were classified into three types: 1 Spiral fibers: Fibers traveling basalward and following the shape of the cochlea were found in both the tunnel of Corti and Nuel's space and believed to be the afferent nerves responsible for innervating the outer hair cells 2 Radial fibers: radiating outward from the osseous spiral lamina—one such radial fiber transversing high in the tunnel space (supposedly the efferent nerve servicing the outer hair cells), and another sort of radial fiber (found crossing the tunnel floor), the nature of which was uncertain. 3 Irregular fibers: Consisting of thin, randomly running fibers within the cochlea. The destination of these fibers was not determined, but possibly they represent transitory nerve branchings of afferent or more probably efferent nerves, which would later regress during maturation.

The effect of bleeding (20% of total blood volume) and of hypervolaemic haemodilution with dextran infusion (20% of total blood volume) on traumatic vasospasm was studied in the central ear arteries of 10 rabbits. The blood pressure dropped significantly after bleeding and the packed cell volume was significantly lower after dextran infusion. Neither treatment had any effect on the duration, intensity or severity of the vasospasm. The results suggest that moderate changes in blood volume do not influence traumatic vasospasm.

The effect of hypothermia on traumatically induced vasospasm was studied in an in vivo model of the rabbit ear artery. Spasm was induced by standardized compression of a 3.2 mm segment of the artery for 3 s. The internal diameter was continuously measured with the aid of an operating microscope during transillumination of the artery. Measurements were begun before spasm induction and continued until the spasm was completely resolved. Spasm was first induced at normothermia and then after reduction of the body temperature by 1.0 degrees C and 1.75 degrees C. The spasm was evaluated in terms of its duration, intensity (% reduction of initial diameter) and severity (area under the curve where diameter was plotted against time). The results were compared with those in a control group which was kept normothermic. Reduction of the body temperature caused a significant increase in the duration of the spasm and increased its severity, but did not influence its intensity.

The effect of isovolemic hemodilution using dextran-60 on arterial blood flow in the rabbit ear was investigated. The animals were anesthetized and an electromagnetic flow probe was applied around the central artery of the ear. Isovolemic hemodilution was performed during a 15 min exchange period. Two degrees of hemodilution were investigated [8.5 and 17 ml dextran-60/kg body weight (b.w.)] and compared with a nontreated control group. The two levels of hemodilution induced reductions in hematocrit to 29 and 21%, respectively, from the control level of about 40%. In all groups, blood pressure maintained constant levels throughout each experiment, which lasted 240 min. In the controls, ear artery blood flow was unchanged or decreased slightly during the experiment. The lower level of hemodilution caused a slight increase of blood flow after 4 h. In the group treated with 17 ml/kg b.w. dextran, blood flow gradually increased after 90 min following hemodilution. After 240 min, flow rates had increased to two- or threefold the initial rate in this group. Although other possibilities exist, the increased blood flow following hemodilution may be interpreted as reflecting a decreased resistance to flow in the tissue due to the decreased viscosity of the blood.

A study was undertaken to develop a model for investigations of traumatically induced vasospasm. The left ear of the rabbit was denervated under short anesthesia. With the animal under light sedation, spasm of the central ear artery was repeatedly induced with a clip applying forceps. To evaluate the vasospasm, the vessel was transilluminated with cold light, and the internal diameter was continuously measured. The spasm was assessed in terms of its duration, intensity (reduction of initial diameter) and severity (integrated change in diameter over time). Repetitive application of the forceps on the same vessel segment shortened the spasm duration. With prolonged pinch duration, the spasm duration was lengthened. The preparation was stable for at least 3 hours. This model was effective for manipulating small vessels and producing spasm and is of potential value for studying the treatment of vasospasm by topical local intra-arterial and systemic methods.

Although it was suggested more than 50 years ago that active elements might have a significant role in cochlear mechanics (Gold 1948), it was not until (1) direct observations of basilar membrane (BM) motion revealed clear differences between in vivo and postmortem responses (Rhode 1973; Cooper et al., Chapter 2) and (2) otoacoustic emissions (OAE) were convincingly recorded in human ear canals (Kemp 1978; Kemp, Chapter 1) that the need to consider the influence of active elements on BM mechanics became compelling. The first active model of cochlear mechanics (Kim et al. 1980b) used negative damping elements as an internal source of mechanical energy and was able to explain the higher sensitivity and sharper tuning characteristic of in vivo responses in contrast to the more broadly tuned, less sensitive postmortem responses.

Many hearing aid users experience physical discomfort when wearing their device. The main contributor to this problem is believed to be deformation of the ear and ear canal caused by movement of the mandible. Physical discomfort results from added pressure on soft tissue areas in the ear. Identifying features that can predict potential deformation is therefore important for identifying problematic cases in advance. A study on the physical deformation of the human ear and canal due to movement of the mandible is presented. The study is based on laser scannings of 30 pairs of ear impressions from 9 female and 21 male subjects. Two impressions have been taken from each subject, one with open mouth, and one with the mouth closed. All impressions are registered using non-rigid surface registration and a shape model is built. From each pair of impressions a deformation field is generated and propagated to the shape model, enabling the building of a deformation model in the reference frame of the shape model. A relationship between the two models is established, showing that the shape variation can explain approximately 50% of the variation in the deformation model. An hypothesis test for significance of the deformations for each deformation field reveals that all subjects have significant deformation at Tragus and in the canal. Furthermore, a relation between the magnitude of the deformation and the gender of the subject is demonstrated. The results are successfully validated by comparing the outcome to the anatomy by using a single set of high resolution histological sectionings of the region of interest.

In the article we discuss the problem of image pre-classification in biometrics identification systems. In such systems acquired images contain various parts of human body. Specifically, we present .ngerprint image classification and we introduce the original method of human ear image pre-classification based on the geometrical approach.

Ultrasound is a pressure wave with a frequency above the audible range of a human ear(18-20 kHz); it is generated by a mechanical motion that induces the molecules in amedium to oscillate around their rest positions. Due to the bonding between themolecules, the disturbance is transmitted to neighboring molecules. The motion causescompressions and rarefactions of the medium and thus a pressure wave travels with themechanical disturbance (Figs. 1 and 2).

Background: Innervation of blood vessels shows inter-species variability. There are few studies on the innervation of human vessels; thus, healthy mesenteric vessels were studied to identify the expression of immunomarkers and the morphology of sympathetic innervation as the basis for a study of mesenteric vessels in inflammatory bowel disease. Methods and Results: Electron microscopy studies examined the relationships of nerves to smooth muscle cells. In veins, nerves were distributed throughout the medial smooth muscle coat, often in close apposition (50 nm) to smooth muscle cells. In arteries, nerves were located at the adventitial-medial border, few closer than 2,000 nm to smooth muscle cells, often with interposing connective tissue and Schwann cell processes. There was a significantly greater nerve density in veins than in arteries (227 vs. 41 mm2; p = 0.03). Immunohistochemical studies revealed the presence of sympathetic and sensory-motor nerves in arteries and veins. Conclusions: It is suggested that in humans with an upright stance, the mesenteric venous system plays a particularly important role in controlling mesenteric capacitance, which is reflected by their dense innervation. It is speculated that transmitters released from perivascular nerves supplying the human mesenteric arteries may play a long-term (trophic) role in addition to short-term signalling roles.

To treat auricular deformities or to perform facial rejuvenation, a plastic surgeon requires normative data for auricular dimensions. The metric standards vary in various ethnic groups, and such data are especially scarce from in India. This study aimed to provide anthropometric information about the normal dimensions of the adult male auricle in central India. A cross-sectional study was undertaken in central India with 415 males categorized in five age groups. Six linear dimensions including the length and width of the auricle, lobule, and concha and the heights of the auricular protrusion at the superaurale and tragal levels were measured. Auricular, lobular, and conchal indices were calculated. The inclination of the auricle relative to its vertical axis was measured. Descriptions of various auricle parts including its shape, preauricular area, form of the helical fold, lobular shape, size, and type of attachment to the cheek were recorded. Almost all the linear measurements showed a steady increase in size with age. The dimensions of the lobule were dependent on its shape and attachment to the cheek. The mean lobular and auricular indices were found to decrease with increasing age, indicating more elongation than widening of the structures. On the average, bilateral asymmetry was observed in all measurements, although only auricular length, width, and conchal length in a few age groups were found to be statistically significant. The frequency distribution of forms of various auricular features is presented. The human ear continues to grow throughout life. The lobule contributes the most to the overall elongation of the auricle. This study furnishes the first set of metric data of auricular dimensions for normal Indian males 18 to 70 years of age. In comparison with other ethnic groups, Indian males seem to have the smallest auricular and lobular lengths, although their respective widths are comparable with those of others.

Due to its semi-rigid shape and robustness against change over time, the ear has become an increasingly popular biometric feature. It has been shown that combining individual biometric methods into multi-biometric systems improves recognition. What features should be used, how they should be captured, what algorithms should be used, and how they should be combined are all open questions. In this paper, we discuss several existing methods of combination and the recognition rates of each.

We have previously shown a constitutively active and noradrenaline-evoked Ca2+-permeable cation channel in rabbit ear artery myocytes which is proposed to have an important role is setting resting ...

Before starting to look at the creative aspects of analog sound synthesis, it's a huge help to develop a basic understanding of the principles of physics governing the whole subject of sound – perhaps because of all the methods of electronic sound creation, analog synthesis is probably the closest to those basic scientific principles. If that means a few hours thinking about what sound really is, how it can most easily be created electronically and how it is interpreted by the human ear, then that time will be more than paid back through a deeper, more intuitive approach to the handling of analog synthesizers, modules and effects. So let's briefly take a look at some very basic physics before starting to look at analog instruments themselves.

MIL-STD-1474E uses the Auditory Hazard Assessment Algorithm for Humans (AHAAH) model to calculate hazard from intense impulses, its theoretic basis providing greatly increased power and accuracy. It is an electro-acoustic analog paralleling the ear’s physiology, including the ear’s critical non-linearities and it calculates hazard from basilar membrane displacements. Successfully developed and tested first with an animal model, a parallel version for the human ear was developed and validated with human data. Given a pressure history as input, AHAAH predicts hazard for the 95%ile susceptible ear. It also makes a movie that allows engineering insight into amelioration of hazard. Hearing protection is accommodated by using input from an acoustic manikin or by implementation of a mathematical protector model using REAT data to calculate input waveforms from free field data. The AHAAH model is also currently used by the Society of Automotive Engineers for calculation of airbag noise hazard, by the Israeli Defense Forces for impulse noise analysis and is being considered by ANSI's S3 Bioacoustics Committee Working Group 62 (Impulse Noise with Respect to Hearing Hazard) as a basis for an ANSI impulse noise standard.

The finite element (FE) method was used to analyze the effect of coupling conditions between the actuator and the round window membrane (RWM) on the performance of round window (RW) stimulation. A FE model of the human ear consisting of the external ear canal, middle ear and cochlea was firstly developed, and then validation of this model was accomplished through comparison between analytical results and experimental data in the literature. Intracochlear pressure were derived from the model under normal forward sound stimulation and reverse RW stimulation. The equivalent sound pressure of RW stimulation was then calculated via comparing the differential intracochlear pressure produced by the actuator and normal ear canal sound stimulus. The actuator was simulated as a floating mass and placed onto the middle ear cavity side of RWM. Two aspects about the actuator coupling conditions were considered in this study: (1) the cross-section area of the actuator relative to the RWM; (2) the coupling layer between the actuator and the RWM. The results show that smaller actuator size can improve the implant performance of RW stimulation, and size requirements of the actuator can also be reduced by introducing a coupling layer between the actuator and RWM, which will benefit the manufacture of the actuator.

Identifying the people by using their ear is the emerging trend in the modern era. Biometrics deals with the procedure to identify people, by using their measurable, unique and permanent features such as fingerprint, iris, face, vein, DNA, hand writing, hand geometry and many more. Biometrics serves as integrated part of modern security systems. This paper discuss about the ear biometrics. Human ear is the unique and clearly visible trait that is permanent for his/her lifetime. The increasing age of human being affects very less on the ear. This paper provides a detailed survey of 16 most popular image databases available for ear biometrics, which will be helpful for the researchers on which they can perform the experiments. This paper includes a comparative study of techniques used for ear detection and ear recognition techniques. Current research work in ear biometrics is limited to database of images captured under certain conditions.

We introduce an unobtrusive sensor-based control system for human-machine interface to control robotic and rehabilitative devices. The interface is capable of directing assistive robotic devices in response to tongue movement and/or speech without insertion of any device in the vicinity of the oral cavity. The interface is centered on the unique properties of the human ear as an acoustic output device. Our work has shown that various movements within the oral cavity create unique, traceable pressure changes in the human ear, which can be measured with a simple sensor (such as a microphone) and analysed to produce commands signals, which can in turn be used to control robotic devices. In this work, we present: 1) an analysis of the sensitivity of human ear canals as acoustic output device, 2) the design of a new sensor for monitoring airflow in the aural canal, 3) pattern recognition procedures for recognition of both speech and tongue movement by monitoring aural flow across several human test subjects, and 4) a conceptual design and simulation of the machine interface system

In Chapter 2 we saw that sound levels are measured according to a logarithmic scale of decibels (dB) and that applying a frequency weighting to simulate the response of the human ear gives A-weighted decibel values (dB(A)). The decibel scale is a logarithmic scale defined relative to a suitable reference value.

Nearly all studies on auditory-nerve responses to electric stimuli have been conducted using chemically deafened animals so as to more realistically model the implanted human ear that has typically been profoundly deaf. However, clinical criteria for implantation have recently been relaxed. Ears with “residual” acoustic sensitivity are now being implanted, calling for the systematic evaluation of auditory-nerve responses to electric stimuli as well as combined electric and acoustic stimuli in acoustically sensitive ears. This article presents a systematic investigation of single-fiber responses to electric stimuli in acoustically sensitive ears. Responses to 250 pulse/s electric pulse trains were collected from 18 cats. Properties such as threshold, dynamic range, and jitter were found to differ from those of deaf ears. Other types of fiber activity observed in acoustically sensitive ears (i.e., spontaneous activity and electrophonic responses) were found to alter the temporal coding of electric stimuli. The electrophonic response, which was shown to greatly change the information encoded by spike intervals, also exhibited fast adaptation relative to that observed in the “direct” response to electric stimuli. More complex responses, such as “buildup” (increased responsiveness to successive pulses) and “bursting” (alternating periods of responsiveness and unresponsiveness) were observed. Our findings suggest that bursting is a response unique to sustained electric stimulation in ears with functional hair cells.

A standardized acoustical coupler should enable the calibration of audiometric earphones which ensures that the hearing thresholds determined in the audiometric measurement are independent of the earphone type. This requires that the coupler approximates the average human ear closely. Nevertheless, the differences among earphones as well as between human ears and the coupler affect the results of the audiometric measurements inducing uncertainty. As the mentioned differences are related to the coupling of different earphones to human ears and to a standardized coupler, the effects of this coupling are investigated by measuring the transfer functions from input voltage of the earphone terminals to the pressure at the ear canal entrance in two situations: open and blocked canals. Since the "ear canal entrance" is not well-defined for the coupler, transfer function measurements in the coupler were carried out in a similar way but at different depths. In order to describe and compare the earphone couplings, the pressure divisions at the entrance of the ear canal are calculated from the measured transfer functions. The results indicate that significant difference appears among sound pressures generated in different individuals' ears. Also, the earphone couplings to human ears and to the coupler differ considerably.

The human ear has discovered a new phenomenon in quantum mechanics. Two reservoirs of superfluid helium, connected only by tiny holes, oscillate when they are pumped to different pressures. This effect is expected, and is analogous to the familiar Josephson effect in electronics, but in the superfluid system it has been exceptionally hard to demonstrate.

Because of the need for automatic, easily repeated physiological measurements in animal models of chronic cardiac disease states, we have developed a rapid and accurate, optically assisted method for determining blood pressure in New Zealand White rabbits. The method relies on the change in the attenuation of laser light through a peripheral ear artery as a function of an externally applied pressure ramp.

We present results of the largest experimental investigation of 3D ear biometrics to date. ICP-based approaches are carefully explored, and the best rank one recognition rate achieves 98.8%. Only 4 cases out of 302 are incorrectly matched. This result is encouraging in that it suggests the uniqueness of the human ear and its potential applicability as a biometric.

Application and research of ear recognition technology is a new subject in the field of biometrics recognition. Earlier research showed that human ear is one of the representative human biometrics with uniqueness and stability. Feasibility and characteristics of ear recognition was discussed and recent advances in 2D and 3D domain was presented. Furthermore, a proposal for future research topics was given, such as ear database generation, ear detection, ear occluding problem and multimodal biometrics with face etc.

Can you hear a whispered voice? Can you hear different types of sound, such as a conversation or music? Everyone with normal ears should answer, “Yes, I can hear these sounds”. Nevertheless, since 1837, science has tried to answer two important questions: how do human ears allow us to hear faint sounds, such as a whispered voice, and how do they allow us to hear sounds at various frequencies? The famous German scientist Helmholtz [1] (1821–1894) attempted to answer these two questions by examining the sensitivity of the ear and its analysis of sound. The human ear consists of the outer, middle, and inner ears (Fig.1). The middle ear plays an important role in the sensitivity of the ear, while the inner ear analyzes sound.

This is the period in which the sound is made rational. The human ear hears sounds selectively, and these sounds are filtered further by the brain into the relevant and irrelevant categories. A studio microphone has no such ability, so the Post-Production Sound folk must do it for us. Stray sounds always creep into our track while we are filming; now we can equalize them out. We also can add interesting new sounds to give the picture more life.

Biometrics identification methods proved to be very efficient, more natural and easy for users than traditional methods of human identification. The future of biometrics leads to passive physiological methods based on images of such parts of human body as face and ear. The article presents a novel geometrical method of feature extraction from human ear images in order to perform human identification.

Two technologies, 3-D reconstruction of human temporal bones and finite element analysis of ear biomechanics, were combined to construct a computational model for describing function of the ear for sound transmission. A set of histological sections of a human temporal bone was prepared, scanned, and digitized for imaging analysis. The aligned and treated images of the middle ear components, external ear canal and middle ear cavity were constructed with attached ligaments, muscles, and tendons. A 3-D CAD model was first created which provided accurate geometric data. Based on the solid model, the finite element (FE) model of the human ear was generated with whole middle ear and ear canal. The dynamic behavior of the FE model was very close to the actual mechanical performance of human temporal bone with 90 dB SPL at the eardrum across auditory frequencies. The model will be further used for acoustic analysis of the ear. (Supported by Whitaker Foundation and OCAST).

Dependence of specific absorption rates (SARs) on the shapes of a human ear during exposure to microwave from a cellular telephone was experimentally evaluated. The local SARs were measured using an electric-field probe in a head phantom of a plastic cubical shell filled with brain-tissue-simulating liquid. It was shown that the shape of the ear strongly affected the SAR distribution in the human head. It was also shown that the measured SAR distributions agreed well with those obtained by the numerical simulation.

A system is described for the analysis of recordings made on infants suffering from a condition of the airway known as stridor. The method is based on the use of a digital filterbank designed to model the critical band response of the human ear. This physiologically based filterbank uses 145 fourth-order bandpass filters whose center frequencies are spaced on a perceptual scale as determined by the critical band theory over the range 100 Hz to 6.4 kHz. Results from three recordings are illustrated and discussed. >

Modelling musical instruments is a particularly challenging task. For these structures, the complexity of both the continuous model and numerical formulation is mainly due to the high sensitivity of the human ear. An overview of the major difficulties are given, with regard to elastic and acoustic field equations, as well as to initial and boundary conditions. To illustrate these features, some recently obtained results in the modelling of some selected instruments are commented. A number of current advances and research perspectives for the near future are briefly described.

How do human ears work? The textbook explanation starts by dividing the ear into three separate anatomical entities that have equally separate functions in converting airborne sound (pressure waves outside the ear) into fluid-borne traveling waves inside the ear, a conversion that makes long-distance hearing on dry land possible ( 1 , 2 ). On page 968 of this issue, Montealegre-Z. et al. ( 3 ) show that although the hearing organ of a rainforest insect looks very different from a human ear, it can be divided into the same three functional entities, providing evidence for convergent evolution.

Transform or subband audio coders can deliver high quality reconstruction at rates around two bits per sample. Most quantization strategies take into account masking properties of the human ear to make the quantization noise less noticeable. In this paper we describe a new coder in which we extend such quantization strategies by incorporating run-length and arithmetic encoders. They lead to improved performance for quasi-periodic signals, including speech. The quantization tables are computed from only a few parameters, allowing for a high degree of adaptability without increasing quantization table storage. To improve the performance for transient signals, the coder uses a nonuniform modulated lapped biorthogonal transform with variable resolution without input window switching. Experimental results show that the coder can be used for good quality signal reproduction at rates close to one bit per sample, and quasi-transparent reproduction at two bits per sample.

Traditional spectrography commonly found in speech sciences laboratories, makes use of fixed bandwidth bandpass analysis filters. The bandwidth can be adjusted to optimise between time and frequency resolution of the output spectrogram as desired. Acoustic analysis by the human ear can be modelled as a bank of bandpass filters whose bandwidth varies as a function of centre frequency. We describe a real-time transputer-based implementation of a spectrograph based on knowledge of peripheral human hearing. The purpose of this paper is to compare and contrast the output from this system with traditional spectrograms for a variety of musical performances to illustrate: (i) the differences between the systems, (ii) psychoacoustic ideas relating to music, and (iii) the complex nature of the signal that is sent to higher centres of neural processing from each ear.

We propose an algorithm to modify the synchronized overlap-and-add (SOLA) technique. SOLA is a popular technique for time scale modification of speech and audio signal. It changes the time scale of the signal while maintaining the pitch information. However, when the time scale of the signal is compressed more, the synthesized speech of SOLA has high articulations rate that it becomes almost impossible for the human ear to comprehend. The proposed algorithm can enhance the quality if the time scaled signal by using a time varying time scale factor which is locally adapted to the input signal. It is found that the intelligibility of the synthesized signal using the proposed algorithm is considerably better than the one synthesized from simple SOLA.

Natural penile prostheses created from the patient's own cells may eliminate the biocompatibility risks associated with artificial prostheses. We previously demonstrated that autologous cartilaginous rods could be created in animal corpus cavernosum as penile prostheses in situ by transplanting autologous chondrocytes on biodegradable polymer scaffolds. In the present study we investigated the possibility of engineering human cartilage rods for potential use as penile prostheses.Chondrocytes isolated from human ear were seeded on rod shaped biodegradable polymer scaffolds (1.2 cm. in diameter, 6.0 cm. long). The seeded scaffolds were maintained in stirred bioreactors for 1 month. Subsequently, the seeded scaffolds were implanted subcutaneously into athymic rats. The specimens were retrieved 2 months after implantation, and histological, structural and mechanical properties were analyzed. The mechanical properties of the engineered prostheses were compared to those of silicone prostheses.Human chondrocytes seeded onto polymer scaffolds formed milk-white cartilaginous rods of the same size as the initial implants. Histological analyses using hematoxylin and eosin, toluidine blue and alcian blue showed mature and well-formed chrondrocytes in the retrieved implants. The engineered human cartilaginous rods were flexible, elastic and able to withstand high degrees of compressive forces. The mechanical properties were comparable to those of commercially available silicone prostheses.Transplantation of chrondrocytes isolated from human ear on polymer scaffolds resulted in the formation of human cartilage rods with the appropriate mechanical properties required for use as penile prostheses. This study demonstrates the feasibility of creating human cartilage rods with a large dimension. This technology may be useful for patients who need penile reconstruction.