bluuebunny/crossref_metadata_2025 huggingface dataset:
Phonotaxis and chorus organization in African frogs
Authors: Bishop Phillip J. , Capranica Robert R. , Passmore Neville I.
Published: October 2013

Detailed studies of the phonotactic behavior and chorus organization of several species of African amphibians were conducted from 1982–1992. A range of phonotactic experiments conducted in two- and three-dimensional arenas, using between one and four loudspeakers and a variety of different stimuli were carried out on the painted reed frog (Hyperolius marmoratus). These experiments revealed the remarkable ability of very small anurans (<30 mm, SVL) to accurately localize a sound source, in both the horizontal and vertical planes. Furthermore, females were able to discriminate between two sound sources that differed in intensity by only 5 dB and their ability was significantly impaired by the introduction of further sound sources. The confounding effect of multiple sound sources on female choice may explain the presence of nonrandom mating with respect to size in this species. The chorus organization of five species of African anurans was investigated by using playback experiments. These experiments revealed four distinct categories of chorus organization which can be plotted on a continuum, from random calling to very precise triggered responses. The type of chorus organization was found to be directly related to the length of the call and the delay in response to the playback stimulus.
Eavesdropping on marine mammals to monitor migration
Authors: Stafford Kathleen
Published: October 2013

Many baleen whales produce low-frequency sounds that are sufficiently loud that they can be detected over long distances. Collectively these sounds contribute significantly to ambient noise levels in the ocean during certain times of the year [Curtis et al., J. Acoust. Soc. Am. 106, 3189–3200 (2000)]. By monitoring the occurrence of these sounds at different locations in the ocean, geographic and seasonal patterns begin to emerge that may be used to document the distribution and basin-scale movements of baleen whales. Each baleen whale species make distinctly different calls so distinguishing among them, and sometimes among populations within species, is possible. Although for many species the ecological function of sound production remains poorly understood, acoustic data can nevertheless be used to examine the seasonal occurrence and migratory behavior of large whales. One example of the utility of monitoring migrations by use of passive acoustics can be seen in the northeastern Pacific where sounds from blue whales are detected in the eastern tropical Pacific from November to May, off the west coast of the United States from July to January and in the Gulf of Alaska from September to December.
Toward a fisheries bioacoustics
Authors: Mann David A.
Published: October 2013

Fisheries bioacoustics is emerging as an application of passive acoustic detection of fish sound production. Many fishes produce sounds during reproductive activities that can be used to determine where and when they are spawning. Autonomous dataloggers and hard-wired hydrophones were used to record sound production by fishes in estuaries of southwest Florida. These data show that passive acoustics can be used to locate spawning sites and determine the timing of spawning by commercially important species. Ultimately fisheries bioacoustics should move the way of fisheries acoustics where the signal output is not the actual sound data, but the locations and intensity of fish spawning. A useful analogy is the development of SONAR systems for fish quantification. These systems do not deliver raw sound data to the researcher. They return processed data on fish location and abundance. One can envision the day when real-time fisheries bioacoustics systems will produce maps of the locations of sound-producing fishes that can provide managers with data on the temporal and spatial extent of spawning.
Expanding uses of ambient noise for imaging, detection, and communication
Authors: Potter John R. , Malod Laurent
Published: October 2013

The use of ambient noise to sense the marine environment has a human history of only two decades. Starting with incoherent processing inspired by optical analogies such as Acoustic Daylight (TM), the exploration of the potential for ambient noise to provide useful information about the environment has blossomed into many related areas and diverse algorithms with connections to multistatic active sonar, classic passive sonar, communications, matched field processing and others. This presentation will introduce some recent work in these areas and attempt to draw together how the use of ambient noise, both by mankind and marine animals, is beginning to form a more complete picture of the potential of this exciting area of research. [Work supported by the Defence Science and Technology Agency, Singapore.]
Passive acoustic detection and measurement of rainfall at sea
Authors: Nystuen Jeffrey A. , Ma Barry
Published: October 2013

It is well recognized that rainfall measurements are needed over the world’s oceans. One method of providing these measurements is to passively listen for the underwater sound signal that is produced by rainfall striking the ocean surface. Since 1998, over 70 buoy-months of ambient sound data have been collected using Acoustic Rain Gauges (ARGs) deployed on deep ocean moorings that form part of the Tropical Atmosphere Ocean (TAO) array in the Pacific Ocean. These data demonstrate the acoustic measurement of oceanic wind and rain. Other ‘‘noises’’ are present in the ocean and need to be detected and rejected. This is accomplished by recognizing the unique spectral and temporal character of rain-generated sound. A quantitative relationship between absolute sound levels and rainfall rate is proposed. The probability of acoustic detection of rainfall events under different weather conditions will be discussed. A quantitative comparison of rainfall accumulation using the acoustic technique with co-located rainfall estimates from on-board R.M. Young rain gauges and from NASA TRMM satellite overpasses (Rainfall Product 3B42) shows promising agreement, but also points out problems associated with each measurement method. [Work supported by ONR—Ocean Acoustics, NSF—Physical Oceanography, and NOAA Office of Global Programs.]
Is anthropogenic ambient noise in the ocean increasing?
Authors: McCarthy Elena , Miller James H.
Published: October 2013

It is commonly accepted that the ocean’s ambient noise levels are rising due to increased human activities in coastal and offshore areas. It has been estimated that low-frequency noise levels increased more than 10 dB in many parts of the world between 1950 and 1975. [Ross, Acoustics Bulletin, Jan/Feb (1993)]. Several other sources cite an increase in manmade, or anthropogenic, noise over the past few decades. [D. A. Croll et al., Animal Conservation 4(1) (2001); Marine Mammal Commission Report to Congress (1999); C. W. Turl, NOSC Tech. Report 776 (1982)]. However, there are few historical records of ambient noise data to substantiate these claims. This paper examines several sectors of anthropogenic activities to determine their contributions to ambient noise. These activities include shipping, oil and gas exploration, military sonar development, and academic research. A series of indices for each of these industries is developed to predict ambient noise trends in the sea. It is found that the amount of noise generated by individual activities may have decreased overall due to new technologies and improved efficiency even if the intensity of such activities has increased.
Model-based tracking of marine mammals near California using seismometers
Authors: Tiemann Christopher O. , Porter Michael B. , Hildebrand John
Published: October 2013

An algorithm originally developed for tracking humpback whales around a deep-water hydrophone array near Hawaii has been proven capable of localizing another species of marine mammal in the shallow waters off California. The new sources of interest are blue whales, animals with markedly different call characteristics from humpback whales, and the data under examination is from four bottom-mounted seismometers in a 3 km square array. The algorithm uses a range-dependent acoustic model to predict time differences of arrival (time-lag) of blue whale calls as measured between sensor pairs, while real pairwise time-lags are measured through a phase-only correlation process. Comparison between modeled and measured time-lags forms an ambiguity surface identifying the most probable whale location in a horizontal plane around the sparse array. The robustness of the model-based localization technique is illustrated in its application to a different scenario than for which it was developed, and it is also suitable for continuous, real-time, unattended alert and tracking applications. Examples of tracking whales along their migratory path will be provided.
Hurricane classification using a full-field ocean surface noise model
Authors: Wilson Joshua D. , Makris Nicholas C.
Published: October 2013

Hurricanes generate noise in the ocean due to wind–wave interaction. The authors have previously discussed the possibility of using this noise to determine the size and strength of the hurricane with a modal model [Wilson and Makris, J. Acoust. Soc. Am. 108 (2000)]. Here the analysis is extended to include a full-field model for surface-generated ocean noise. Unlike previous surface noise models that contained far-field approximations, this full-field model can be used to calculate the acoustic field both inside and outside the hurricane. This full-field model is used to calculate the spatial covariance of the acoustic field generated by a hurricane. This spatial covariance is then used to determine the sound from a hurricane that would be detected by hydrophones and hydrophone arrays. Several examples are presented using single sensors and sensor arrays inside and outside the hurricane to determine the best method for classifying a hurricane. In addition shallow- and deep-water environments are compared to illustrate their effect on the propagation of surface-generated hurricane noise. Also simulations are shown for multiple frequencies to show the filtering effect of the waveguide on the propagation and to determine the optimal frequency for hurricane classification.
Upcoming new international measurement standards in the field of building acoustics
Authors: Goydke Hans
Published: October 2013

The extensively completed revision of most of the ISO measurement standards in building acoustics mainly initiated by the European Commissions demand for harmonized standards emphasized the insight that the main goal to avoid trade barriers between the countries can only be reached when the standards sufficiently and comprehensively cover the field when they are related to the actual state of the art and when they are sufficiently related to practice. In modern architecture one can observe the rapid change in the use of building materials, for instance regarding the use of glass. Lightweight constructions as well as heavyweight building elements with additional linings are increasingly in common use and unquestionably there are consequences to be considered regarding the ascertainment of sound insulation properties. Besides others, International Standardization is unsatisfactory regarding the assessment of noise in buildings from waste water installations, in the low frequency area and in general regarding the expression of uncertainty of measurements. Intensity measurements in building acoustics, rainfall noise assessment, estimation of sound insulation, impulse response measurement methods, assessment of sound scattering are examples of upcoming standards.
Pitch jnd and the tritone paradox: The linguistic nexus
Authors: Safari Kourosh
Published: October 2013

Previous research has shown a connection between absolute pitch (the ability to name a specific pitch in the absence of any reference) and native competence in a tone language (Deutsch, 1990). In tone languages, tone is one of the features which determines the lexical meaning of a word. This study investigates the relationship between native competence in a tone language and the just noticeable difference of pitch. Furthermore, the tritone paradox studies have shown that subjects hear two tritones (with bell-shaped spectral envelopes) as either ascending or descending depending on their linguistic backgrounds (Deutsch, 1987). It is hypothesized that the native speakers of tone languages have a higher JND for pitch, and hear the two tones of the tritone paradox as ascending, whereas, native speakers of nontone languages hear them as descending. This study will indicate the importance of early musical training for the development of acute tone sensitivity. It will also underline the importance of language and culture in the way it shapes our musical understanding. The significance of this study will be in the areas of music education and pedagogy.
The effects of timbre on melody recognition are mediated by familiarity
Authors: McAuley J. Devin , Ayala Chris
Published: October 2013

Two experiments examined the role of timbre in music recognition. In both experiments, participants rated the familiarity of a set of novel and well-known musical excerpts during a study phase and then were given a surprise old/new recognition test after a retention interval. The recognition test was comprised of the target melodies and an equal number of distractors; participants were instructed to respond yes to the targets and no to the distractors. In experiment 1, the timbre of the melodies was held constant throughout the study and then either stayed the same or switched to a different instrument sound during the test. In experiment 2, timbre varied randomly from trial to trial between the same two instruments used in experiment 1, yielding target melodies that were either mismatched or matched in their timbre. Switching timbre between study and test in experiment 1 was found to hurt the recognition of the novel melodies, but not the familiar melodies. The mediating effect of familiarity was eliminated in experiment 2 when timbre varied randomly from trial to trial rather than remaining constant. Possible reasons for the difference between studies will be discussed.
Recreating the real, realizing the imaginary—a composer’s preoccupation with acoustic space
Authors: Godman Rob
Published: October 2013

For centuries composers have been concerned with spatialization of sound and with the use of acoustic spaces to create feeling, atmosphere, and musical structure. This paper will explore Rob Godman’s own use of sound in space, including (1) his treatment of ancient Vitruvian principles and how they are combined with new technologies; (2) an exploration of virtual journeys through real and imaginary acoustic spaces; (3) how sounds might be perceived in air, liquid, and solids; and (4) how technology has allowed composers to realize ideas that previously had only existed in the imagination. While focusing on artistic concerns, the paper will provide information on research carried out by the composer into acoustic spaces that are able to transform in real time with the aid of digital technology (Max/MSP software with sensor technology) and how these have been used in installation and pre-recorded work. It will also explore digital reconstructions of Vitruvian theatres and how we perceive resonance and ambience in the real and virtual world.
Music-therapy analyzed through conceptual mapping
Authors: Martinez Rodolfo , de la Fuente Rebeca
Published: October 2013

Conceptual maps have been employed lately as a learning tool, as a modern study technique, and as a new way to understand intelligence, which allows for the development of a strong theoretical reference, in order to prove the research hypothesis. This paper presents a music-therapy analysis based on this tool to produce a conceptual mapping network, which ranges from magic through the rigor of the hard sciences.
An overview of musical instruments used in South American dance traditions
Authors: Wheeler Paul A.
Published: October 2013

Musical instruments used in South American dances combine elements from Amerindian, African, and European musical traditions. The Amerindian influence can be seen in Andean instruments, such as the end-blown flute, panpipe, and charango (modified from the European guitar). The berimau, a musical bow used in the Brazilian capoeira dance, is an example of African influence. The bandoneon is a square-ended German concertina most famous for its use in the tango from Argentina. This paper provides an overview of the musical instruments commonly used in South American dance traditions in relationship to their origins. The acoustics of some of these instruments, such as the guitar, has been studied in detail, whereas others, like the Brazilian cuica, provide opportunity for new studies.
A web-based noise control prediction model for rooms using the method of images
Authors: Dance Stephen
Published: October 2013

Previous simple models could only predict sound levels in untreated rooms. Now, using the method of images, it has become possible to accurately predict the sound level in fitted industrial rooms from any computer on the Internet. Thus, a powerful tool in an acoustician’s armory is available to all, while requiring only the minimal amount of input data to construct the model. This is only achievable if the scope of the model is reduced to one or two acoustic parameters. Now, two common noise control techniques have been implemented into the image source model: acoustic barriers and absorptive patches. Predictions using the model with and without noise control techniques will be demonstrated, so the advantages can be clearly seen in typical industrial rooms. The models are now available on the web, running directly inside Netscape or Internet Explorer.
Application of indoor noise prediction in the real world
Authors: Lewis David N.
Published: October 2013

Predicting indoor noise in industrial workrooms is an important part of the process of designing industrial plants. Predicted levels are used in the design process to determine compliance with occupational-noise regulations, and to estimate levels inside the walls in order to predict community noise radiated from the building. Once predicted levels are known, noise-control strategies can be developed. In this paper an overview of over 20 years of experience is given with the use of various prediction approaches to manage noise in Unilever plants. This work has applied empirical and ray-tracing approaches separately, and in combination, to design various packaging and production plants and other facilities. The advantages of prediction methods in general, and of the various approaches in particular, will be discussed. A case-study application of prediction methods to the optimization of noise-control measures in a food-packaging plant will be presented. Plans to acquire a simplified prediction model for use as a company noise-screening tool will be discussed.
Encapsulated bubble dynamics
Authors: Allen John
Published: October 2013

The study of a bubble encapsulated by a fluid or an elastic shell is a subject of interest for a wide variety of applications. In particular, ultrasound contrast agents are encapsulated bubbles 1–5 microns in radius developed for diagnostic imaging and, more recently, therapeutic purposes involving drug delivery. The previous formulations of the equations for encapsulated bubbles have originated from a generalized Rayleigh–Plesset equation, which follows from the Eulerian form of the fluid dynamics equations. Dynamic formulations of empty spherical shells in an inviscid medium have been also developed independently of these gas bubble studies. Little effort has gone into unifying the two approaches. The equations for a gas-filled incompressible, isotropic elastic spherical shell are derived from the Lagrangian frame using the first Piola–Kirchoff stress tensor. Some previous results are obtained and compared in different limiting cases. Instabilities of the shell are determined for sufficiently flexible shell materials or high internal gas pressures. Also highlighted are the nonspherical instabilities associated with acoustically driven bubbles with fluid shells of different density and viscosity than that of the surrounding fluid.
Evidence for nuclear emissions during neutron seeded acoustic bubble cavitation
Authors: Taleyarkhan R. P. , West C. D. , Cho J. S. , Lahey R. T. , Block R. C. , Nigmatulin R.
Published: October 2013

In cavitation experiments with deuterated acetone, statistically significant tritium decay activity above background levels was detected. In addition, evidence for statistically significant neutron emissions near 2.5 MeV was also observed, as would be expected for deuterium–deuterium fusion. Control experiments with normal acetone did not result in tritium activity or neutron emissions. Hydrodynamic shock code simulations supported the observed data and indicated compressed, hot (106–107 K) bubble implosion conditions, as required for thermonuclear fusion reactions. Separate experiments with additional fluids are under way and results appear to support those observed with acetone. Scalability potential to higher yields, as well as evidence for neutron−tritium branching ratios are presented.
Statistical characteristics of cavitation noise
Authors: Vokurka Karel
Published: October 2013

Cavitation noise originates as a superposition of pressure waves emitted during oscillations of individual cavitation bubbles. These pressure waves contain useful information on bubbles generating them and efforts are done to extract it. Unfortunately the pressure waves emitted by different bubbles usually overlap heavily and thus in experiments it makes sense to measure statistical characteristics only. Typical statistical characteristics determined experimentally encompass autospectral densities and instantaneous autospectra. To be able to extract information concerning the oscillating bubbles, suitable models of both cavitation bubbles and cavitation noise are necessary. It has been found out recently that a reasonable insight into the cavitation noise structure may be obtained by simulating cavitation noise on a computer and comparing statistical characteristics of simulated cavitation noise with those determined experimentally. By varying different parameters in theoretical models used to simulate the noise, a good agreement between the simulated and measured cavitation noise statistical characteristics can be obtained. The models parameters thus found may be then analyzed from a physical point of view and conclusions on behavior of cavitation bubbles can be drawn. [Work supported by the Ministry of Education of the Czech Republic as the research Project No. MSM 245100304.]
On the lateralization of the Huggins pitch
Authors: Zhang Peter Xinya , Hartmann William M.
Published: October 2013

The central activity pattern (CAP) model of Raatgever and Bilsen [J. Acoust. Soc. Am. 80, 429–441 (1986)] correctly predicts that Huggins pitch (HP+) is lateralized in the center whereas HP− is lateralized to the left or the right. Experiments show that some listeners (left-eared listeners) always hear the pitch sensation on the left and others always hear it on the right. Still others can hear it on one side or the other. The CAP model also predicts that the laterality of HP− should follow a hyperbolic function of the boundary frequency. To test this prediction, laterality was measured in careful laterality estimation experiments, wherein HP− was combined with a set of interaural time differences (ITDs). Although laterality estimates followed predictions for finite (ITDs), on those trials where the ITD was zero the hyperbolic law was violated for five out of five listeners. Instead, the laterality of HP− was very insensitive to the boundary frequency over the range tested, 200 to 1000 Hz. A search for a satisfactory variation on the CAP model continues. [Work supported by the NIDCD under Grants Nos. DC00181 and DC00100.]
Noise addiction
Authors: Elizondo-Garza Fernando J.
Published: October 2013

Progress in understanding the brain processes involved in addiction to chemicals has resulted in the recognition of other forms of addiction related to energy and information, i.e., TV and Internet. In that context noise becomes a cause of addiction and, therefore, it is necessary to develop more adequate approaches even to conceptualize noise addiction. In this presentation some of the main aspects to be considered to approach an operational definition of noise addiction are discussed.
Validation of audiometric method for measuring temporary threshold shifts
Authors: Ordoñez Rodrigo , Karariga Ioanna-Rigina , Karlsen Brian L. , Reuter Karen , Hammersho/i Dorte
Published: October 2013

The proposed experiment aims at testing the audiometric method developed earlier [Ordoñez et al., Acta Acustica (Beijing) 88, 450–452 (2002)] by evaluating if it is able to reproduce some of the known aspects of temporary threshold shifts (TTS), such as: Immediate sensitization, the 2 min maximum of the recovery and the half-octave shift of the peak of TTS. The subjects will be exposed to pure tones of 500 Hz and 2 kHz for 2 to 5 min and the levels will cover the range between 40- to 100-dB SPL. The aim is to induce a maximum of 15 dB of TTS. For showing the half-octave shift, the threshold will be determined from one octave below the exposure frequency to one octave above in 1/2 octave steps. For the 2 min maximum, the threshold will be measured at the most affected frequency and it can be determined continuously for 4 min after the exposure. Sensitization at probe frequencies lower than the exposure frequencies will be tested by measuring the threshold at 1/2 and 1 octave below the exposure frequency.
Auscultation in noise: A program to develop a stethoscope capable of functioning during aeromedical transport
Authors: Cain Paul A. , Ahroon William A. , Sewell John M. , Bernhard William N.
Published: October 2013

U.S. Army helicopters used to provide aeromedical transport are extremely noisy (105 dB). This prevents auscultation with current stethoscopes. Ten subjects used four different stethoscopes in noise at 70–100 dB in order to determine the detection threshold of a body sound. The stethoscopes differed in performance (p=0.001); the best being the acoustic, followed by the three electronic stethoscopes. The threshold of noise for the detection of heart and breath sounds was 80 dB and 70–75 dB, respectively. A comparison of a standard stethoscope and one modified with Communications Ear Plugs revealed a difference (p=0.05) at 70 and 80 dB that disappeared at higher noise levels, implying that it was not simple masking, but that noise was amplified after entering the sensing head. Despite the poorer performance of the electronic stethoscopes, the need for a gain of 30–35 dB indicated that this was the preferred route for development. A sensor with an acoustic impedance match close to body tissue, but poorly matched to air-coupled noise, was developed, and trials indicate that heart sounds can be heard at 105 dB. Development continues with the aim of reducing or eliminating the need for signal processing.
Vibrations of raised access floors
Authors: Amick Hal , Gendreau Michael , Gordon Colin G.
Published: October 2013

Raised access floors play a critical role in modern cleanroom design. They have unique mechanical properties that make them respond to dynamic loading in a manner quite different from conventional floors. For example, an unbraced floor is much more flexible horizontally than in the vertical direction. Horizontal vibration amplitudes with walker excitation may exceed 100 μm/s in an unbraced floor, exceeding the sensitivity of 1000× inspection microscopes by as much as an order of magnitude. Issues such as these become important when moderately vibration-sensitive instruments, such as optical microscopes, are supported on access floors, typically the case in cleanrooms. This paper presents results of experimental studies involving a 3 m×3 m segment of floor and a large floor installed in a cleanroom, both of which were subjected to dynamic loads using a shaker. Both drive-point and propagation properties were examined. In addition, data are presented for variations in bracing and bolting using the 3 m×3 m segment.
Evidence of the existence of phononic band gaps: A practical example of a tunable sound insulation by a periodic device of rods
Authors: Goffaux Cecile , Lambin Philippe , Vigneron Jean-Pol , Maseri Fabrizio
Published: October 2013

Based on the principle of phononic band gap materials, the control of acoustic frequency gaps by altering the geometry of the system is analyzed in the particular case of a set of parallel solid square-section columns distributed in air on a square lattice. This system is shown to be sensitive enough to the rotation of the columns to be considered for a practical sonic band gap width engineering. For different geometric configurations, experimental and theoretical results are presented and a discussion about the application of such structures as sound insulators is discussed. We acknowledge the use of the Namur Scientific Computing Facility (Namur-SCF), a common project between FNRS, IBM Belgium, and the Facultés Universitaires Notre-Dame de la Paix (FUNDP). [C. Goffaux acknowledges the financial support of the FIRST program of the Walloon Region Government and the Research and Development Centre of Cockerill-Sambre (ARCELOR Group).]
Physics of a pneumatic vibration isolator revisited
Authors: Ryaboy Vyacheslav M.
Published: October 2013

This paper gives detailed consideration to two phenomena that affect the performance of a pneumatic isolator but have not received adequate attention in the past. The first one is the thermal conductivity of gas. It is usually assumed that the compression of gas in the pneumatic chamber is an adiabatic process. Thermal conductivity can, nevertheless, affect the performance, especially in the low-frequency domain and for small-size isolators. A simple explicit expression for the acoustic compliance is derived from exact solution of conductive gas equations in the cylindrical domain. Another factor affecting the isolator response is the stiffness introduced by the diaphragm. A formula for the stiffness is derived based on the mathematical model of the diaphragm as an elastic membrane. Comparison to experimental data shows that adequate representation of these two factors results in accurate predictions of the isolator performance as a function of the supported load.
Feature extraction and models for speech: An overview
Authors: Schroeder Manfred
Published: October 2013

Modeling of speech has a long history, beginning with Count von Kempelens 1770 mechanical speaking machine. Even then human vowel production was seen as resulting from a source (the vocal chords) driving a physically separate resonator (the vocal tract). Homer Dudley’s 1928 frequency-channel vocoder and many of its descendants are based on the same successful source-filter paradigm. For linguistic studies as well as practical applications in speech recognition, compression, and synthesis (see M. R. Schroeder, Computer Speech), the extant models require the (often difficult) extraction of numerous parameters such as the fundamental and formant frequencies and various linguistic distinctive features. Some of these difficulties were obviated by the introduction of linear predictive coding (LPC) in 1967 in which the filter part is an all-pole filter, reflecting the fact that for non-nasalized vowels the vocal tract is well approximated by an all-pole transfer function. In the now ubiquitous code-excited linear prediction (CELP), the source-part is replaced by a code book which (together with a perceptual error criterion) permits speech compression to very low bit rates at high speech quality for the Internet and cell phones.
Convolutive mixture separation in time–frequency domain for robust automatic speech recognition
Authors: Kadambe Shubha L.
Published: October 2013

In a mobile environment, automatic speech recognition (ASR) systems are being used for information retrieval. Due to the presence of multiple speakers, noise sources and reverberations in such environments, the ASR performance degrades. Here, the problem of improvement of ASR performance by separating the convolutively mixed speech signals that predominantly exist in mobile environments is addressed. For the separation, an extension of the algorithm published in A. Ossadtchi and S. Kadambe [‘‘Over-complete blind source separation by applying sparse decomposition and information theoretic based probabilistic approach,’’ ICASSP, 2001] is applied in the time–frequency domain. In the extended algorithm, the dual update algorithm that minimizes L1 and L2 norms simultaneously is applied in every frequency band. The problem of channel swapping is also addressed. The experimental results of separation of convolutively mixed signals indicate about 6-dB SNR improvement. The enhanced speech signals are then used in GMM based continuous speech recognizer. The recognition experiments are performed using the real speech data collected inside a vehicle. During the presentation, complete ASR performance improvement results will be provided.
A Gaussian-selection-based preclassifier for speaker identification
Authors: Roch Marie A.
Published: October 2013

For practical reasons driven by the need to periodically adapt speaker models or enroll new members of the population, most speaker identification systems train individual models for each speaker. When classifying a speech token, the token is scored against each model and the maximum a posteriori decision rule is used to decide the classification label. Consequently, the cost of classification grows linearly for each token as the population size grows. When considering that the number of tokens to classify is also likely to grow linearly with the population, the total work load increases exponentially. In this work, a new system is presented which builds upon the so-called ‘‘Gaussian selection’’ techniques. The system uses the speaker-specific models as source data and constructs N-best hypotheses of speaker identity. The N-best hypothesis set is then evaluated using individual speaker models. This process results in an overall reduction of workload. The cost of the model generation is low enough to permit enrollment and adaptation, and the accuracy of the preclassifier is such that there is minimal impact on the recognition rate.
Quality of service (QoS) on public telephonic networks for multimedia transmission systems
Authors: Alvarez-Ballesteros Salvador , Alvarez-Rangel Miguel
Published: October 2013

The object of this paper is to determine which QoS maximum can be obtained by applying commercial telecommunications technology in the transmission of audio and video on public telephone lines and the Internet, procuring to achieve the necessary quality to reach the conditions required on H323. It is certain that the top technology that allows to assure that the QoS is most demanding, are a reality. However, these technologies alone pay off practically under conditions that are not very feasible for formalizing would be of the ambient control of the laboratory. In this work we analyzed the technical problems of the telecommunications that affect the yield of the links for applications of multimedia on the Internet.
The Geoclutter Experiment 2001: Remote acoustic imaging of sub-bottom and seafloor geomorphology in continental shelf waters
Authors: Makris Nicholas C. , Ratilal Purnima , Lai Yisan , Symonds Deanelle T. , Ruhlmann Lilimar A. , Scheer Edward K.
Published: October 2013

In the Geoclutter experiment of April–May 2001, an active sonar system was used to remotely and rapidly image geomorphology over wide areas in continental shelf waters by long-range echo sounding. The bistatic system, deployed in the strataform area south of Long Island, imaged extensive networks of buried river channels and inclined subseafloor strata over tens of kilometers in near real time. Bathymetric relief in the strataform area is extremely benign. The vast majority of features imaged apparently correspond to sub-bottom geomorphology that sound waves reach after tunneling as well as propagating through the overlying sediment. Returns from buried river channels were often found to be as discrete and strong as those from calibrated targets placed in the water column. Since buried river channels are expected to be ubiquitous in continental shelf environments, sub-seafloor geomorphology will play a major role in producing ‘‘false alarms’’ or clutter in long-range sonar systems that search for submerged objects such as underwater vehicles or marine mammals. Wave guide scattering and propagation are inherent to this new remote sensing technology because source signals are transmitted over hundreds of water-column depths in range to image sub-seafloor and seafloor geomorphology.
Fish schools as potential clutter and false targets: Observations on the New Jersey shelf
Authors: Nero Redwood W. , Thompson Charles H. , Love Richard H.
Published: October 2013

Fish schools can appear as clutter or false targets on search sonars and can confuse the interpretation of scattering from the sea floor. During Boundary Characterization 2001, a high-frequency echosounder was used to quantify fish schools in an effort to provide estimates of false targets and clutter at low frequency. Schools were quantified from the echosounder data using an image processing algorithm designed to provide estimates of school size, acoustic intensity, and a variety of diagnostic features. The number of schools that had the potential to be low-frequency false targets was estimated using information on fish species obtained from fisheries research trawls and an NRL swimbladder scattering model. A few pelagic fish schools of intermediate size and high intensity, with low-frequency target strengths estimated at +12 dB, occurred near the sea surface at night in the northern corner of the study site, at a density of about one per km2. These schools were most likely to appear as false targets. Demersal fish, those near the sea floor, although abundant along the 80-m contour, were not likely to be strong false targets at low frequency. [Work supported by ONR.]
Modal inversion results for geoacoustic properties in the SWAT experiments
Authors: Ohta Kazuhiko , Okabe Kouki , Oikawa Masanichi , Morishita Itaru , Murakami Hirotaka , Frisk George V.
Published: October 2013

Bottom sediment properties at sites on the New Jersey Shelf and in the East China Sea were studied in the Shallow Water Acoustic Technology (SWAT) experiments. In these experiments, a source towed at constant depth transmitted low-frequency cw signals, which were measured on a bottom-moored vertical line array. The Hankel transform was applied to the acoustic field measured on the resulting synthetic aperture horizontal array created at each receiver depth. The horizontal wave number spectra, with peak positions corresponding to the modal eigenvalues, were observed to be slightly different among the different receiver depths, partially due to noise and range dependency. Thus stochastic mode inversion was exploited by using all of the observed peak positions for estimation of the geoacoustic properties. The sound field simulated using the inversion results agrees well with the measured one for each receiver depth.
Source tow geoacoustic inversions from the 2001 ASIAEX East China Sea experiment
Authors: Huang Chen-Fen , Hodgkiss William S.
Published: October 2013

During the 2001 ASIAEX East China Sea experiment, source tow data were collected by a 16-element, 75-m aperture, autonomously recording vertical line array in 105-m-deep water. Transmissions from two similar 6-km-long tracks have been analyzed. In the first, CW tonals at 95, 195, 295, 395, 805, 850, and 905 Hz were transmitted from a J-15 transducer at a nominal depth of 46 m. In the second, CW tonals at 1.6, 2.4, 3.5, and 4.4 kHz were transmitted from an ITC-2015 transducer at a nominal depth of 49 m. Inversion results for seafloor geoacoustic parameters from these transmissions will be presented. [Work supported by ONR.]
Psychophysical and physiological measures of spectro-temporal processing in humans
Authors: Eddins David A. , Eddins Ann C.
Published: October 2013

The normal perception of natural acoustic stimuli requires the brain to extract, encode, and interpret multidimensional patterns derived from the acoustic input as relayed by the auditory periphery. Of particular importance in audition are patterns of intensity variations across time and frequency. To better understand the relation between perceptual abilities and underlying physiological mechanisms, one may study the relation between measures of psychophysical performance and physiological coding in humans on a range of auditory tasks. Furthermore, similar physiological measures are easily obtained in a variety of animal species, providing a critical link between human perception and relevant animal models. The first series of experiments to be reviewed involves behavioral and physiological measures of auditory temporal processing including the perception of sinusoidal amplitude modulation and nonsimultaneous masking. The second series involves the perception of spectral envelope features using behavorial and physiological estimates of the spectral modulation transfer function. The ability to combine or compare temporal patterns across different spectral regions will be examined via the comodulation masking release (CMR) paradigm. Finally, the processing of local and global spectral features will be examined and hemispheric dominance for each will be discussed.
Neural response characteristics in auditory cortex of the awake ferret
Authors: Depireux Didier A. , Chen Bing-Zhong , Marvit Peter , Li Yaan
Published: October 2013

We are developing an awake preparation for chronic physiological recording in the ferret. In this talk, we describe neural responses in auditory cortex in the restrained preparation to a variety of acoustic stimuli including tones, noise, auditory gratings, and their combinations. We characterize population responses, show how the cells properties change as a function of the stimulus (e.g., how the receptive field of a cell changes, depending on whether the carrier under the gratings spectral envelope is a harmonic complex or noise) and correlated the activity of single units from neighboring cells in a cortical column in response to these stimuli. [Work supported in part by NIH Grant No. R01 DC05019-01A1 and a training grant to the Program in Neuroscience at UMAB.]
Audiomotor integration for active sensing in the echolocating bat, Eptesicus fuscus
Authors: Moss Cynthia , Sinha Shiva
Published: October 2013

Echolocation depends upon the dynamic interplay between auditory information processing and adaptive motor control. We are conducting experiments aimed at understanding the neural mechanisms supporting audiomotor integration for echolocation in the big brown bat, Eptesicus fuscus. In this work we focus on the superior colliculus (SC), a midbrain structure implicated in species-specific orienting behaviors. We have characterized the spatial response profiles of auditory neurons in the bat SC, and have discovered a population of cells that show echo-delay tuning, a response property believed to encode target distance in the bats sonar receiver. These data reveal a 3-D spatial coordinate system that may be used to guide appropriate orienting responses. Our studies also demonstrate that the bat SC plays a functional role in the execution of motor commands used for acoustic orientation by sonar. In particular, SC microstimulation elicits head and pinna movements, along with the production of sonar vocalizations. Multi-unit recordings from the SC of tethered, vocalizing bats reveal bursts of neural activity preceding the production of each sonar cry. Collectively, these results suggest that the bat SC plays a functional role in both auditory information processing and orienting behaviors that operate together in echolocation. [Work supported by the NSF, the NIMH, and the Whitehall Foundation.]
Neuroethology of audition and bat evasion in praying mantises
Authors: Yager David D.
Published: October 2013

Many praying mantises have a unique auditory system comprising a single ear located in the ventral midline of the thorax. The hearing is nondirectional, and best frequencies range from 25 kHz to over 100 kHz depending on the species. Bat-like ultrasound triggers complex evasive maneuvers in flying mantises that requires CNS processing in the head. A mirror-image pair of interneurons (501) rapidly (<20 ms ) carries auditory information from the auditory nerve to the brain and these neurons are the best candidates as the primary input to the evasive response. The 501 recordings from an electrode chronically implanted in a mantis while it is being attacked by a flying, echolocating bat show that 501 responds strongly to bat cries and faithfully reports the temporal pattern of the echolocation cries during the early stages of the attack. However, during the last 200–250 ms before capture (beginning in mid-Buzz I), 501 falls silent. Although consistent with several physiological characteristics of 501, the result is surprising behaviorally. However, based on behavioral latencies, the latest that a successful response could be triggered is 200–250 ms before capture, and silencing 501 after that may prevent potentially dangerous habituation of the interneuron.
Time and frequency information processing in the midbrain: Evidence found in the gerbil inferior colliculus
Authors: Riquimaroux Hiroshi , Maki Katuhiro
Published: October 2013

We have investigated the firing pattern of neurons in the central nucleus of the inferior colliculus (ICc) in time-frequency coordinate. The ICc is the major nucleus in the auditory midbrain. Single-unit recordings were made from ICc contralateral to the monaurally stimulated ear in anesthetized gerbils. We could classify firing patterns into four groups, except the simple ON neurons. Three out of four groups of neurons (53.8%) demonstrated that firing distribution changed depending on time and frequency, which was not shown previously. One group (37.6%) exhibited a frequency response range that changed little with time. The remainder (8.6%) belonged to none of the above. The time-frequency sensitive neuron in ICc may be a good candidate to code communication sounds, which comprise complex temporal change in frequency. [Research supported by Special Coordination Funds from the Science and Technology Agency and a grant to RCAST at Doshisha University from the Ministry of Education and Science of Japan.]
The relative contribution of stress waves and cavitation to the overall success of stone comminution in shock wave lithotripsy
Authors: Zhong Pei , Zhu Songlin , Zhou Yufeng
Published: October 2013

The disintegration of kidney stones in shock wave lithotripsy (SWL) is caused primarily by the stress waves propagating inside the stone and by the collapse of cavitation bubbles in the surrounding fluid near the stone surface. Understanding the relative contribution of these different mechanical forces to the overall success of stone comminution is critical for improving the treatment efficiency of SWL. In this talk, we will provide an overview of the experimental studies under way at Duke University to delineate the contribution of stress waves and cavitation to the overall success of stone comminution in SWL. Limitations of individual contributing factors and their synergistic interaction will also be discussed. Finally, strategies to improve stone comminution efficiency while reducing tissue injury in SWL will be presented. [Work supported by NIH DK52985 and DK58266.]