bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound insulation in residential buildings
Authors: George Ballard W.
Published: September 2008

This paper considers similarities and differences experienced with sound insulation in various types of residential buildings, such as townhouses and condominiums. Typically with two adjacent dwelling units, there is a primary inter-unit sound path, such as a party wall, and other paths that are categorized as flanking paths. In typical condominiums and apartments, the floor/ceiling is also a primary path. Implications of the plywood subfloor extending across the party wall are discussed. Avantages along with potential limitations of double stud party walls in controlling noise flanking transmission by the subfloor path are shown. Diagonal noise transmission between units is a factor that is common to both townhouse and apartment and condominium types of buildings. An example is given of the conversion of a single famiy house to a vertically-separated duplex, with implications regarding the closing off of the stairs and isolation of the garage from the neighbor unit. The exterior wall, due to its proximity to the neighboring building, acted to some extent as a ‘‘party wall’’ assembly. An example is also given of a ‘‘defacto’’ townhouse where settling had caused the exterior wall of one single dwelling to butt against another house.
Evolution of sound localization in lizards
Authors: Carr Catherine , Tang Yezhong , Christensen-Dalsgaard Jakob
Published: September 2008

Tympanic hearing may have developed independently in four major tetrapod groups, the anurans, lepidosaurs, archosaurs, and mammals. The emergence of a tympanic ear would have increased the frequency range and sensitivity of hearing. Furthermore, early tympana were acoustically coupled through the mouth cavity and therefore must have acted as pressure difference receivers, which are inherently directional, obviating a need for central computation of ITD and ILD. In lizards, this acoustical coupling generates a large directional difference at the tympanum and recordings from auditory nerve are strongly ITD- and ILD-dependent. To separate neural from acoustical interactions, interaural transmission in a gecko was blocked to reveal true binaural neurons in nucleus magnocellularis, nucleus angularis, and superior olive. The function of these neurons with naturalistic, i.e., free-field stimulation may be to sharpen the directional response, a mechanism similar to that suggested for teleost fish. The closure of the middle ear cavity in the mammals and some birds is a derived condition, and may have profoundly changed the operation of the ancestral tetrapod ear by decoupling the tympana, improving the low-frequency response of the tympanum, and leading to a requirement for neural computation of directionality in the central nervous system.
Are binaural cues available for sound source localization in teleost fishs?
Authors: Edds-Walton Peggy , Fay Richard
Published: September 2008

When reading the review literature regarding directional hearing or sound source localization by fishs, one usually sees a list of reasons why fish cannot use binaural cues. The assumptions are that teleost fishs cannot detect left versus right differences in arrival times (due to the speed of sound in water), amplitude differences (due to the closeness of the ears and the acoustic transparency of the tissues), nor phase differences (due to the long wavelengths of the frequencies most fish can hear best). However, there is some behavioral evidence that fishs can distinguish the direction of a sound source, if not the actual location. We will present evidence that there are potential binaural cues that might be available given left versus right differences in auditory input to the brain that are the result of both anatomical organization and physiological mechanisms. In addition, sharpened directional responses are present in the medulla and the midbrain, which are likely to be due to binaural computations. [Work funded by the National Institutes of Health, NIDCD.]
Sound localization by echolocating dolphins
Authors: Branstetter Brian K. , Mercado Eduardo
Published: September 2008

Dolphins (and other odontocetes) rely on echolocation to aid in detecting, identifying, localizing, and capturing prey. Dolphin sonar signals are well suited for localizing multiple, small targets in a three-dimensional aquatic environment by utilizing highly directional (3 dB beamwidth of about 10 deg), broadband (3 dB bandwidth typically of about 40 kHz; peak frequencies between 40 kHz and 120 kHz), short duration clicks (about 40 μs). Dolphins can localize sounds both passively and actively (echolocation) with a resolution of about 1 deg. Cross-modal matching (between vision and echolocation) suggests dolphins perceive the spatial structure of complex objects interrogated through echolocation, a feat that likely requires spatially resolving individual object features and integration into a holistic representation of object shape. Although dolphins are sensitive to small, binaural intensity and time differences, mounting evidence suggests dolphins employ position-dependent spectral cues derived from well developed head-related transfer functions, for sound localization in both the horizontal and vertical planes. A very small temporal integration time (264 μs) allows localization of multiple targets at varying distances. Localization adaptations include pronounced asymmetry of the skull, nasal sacks, and specialized lipid structures in the forehead and jaws, as well as acoustically isolated middle and inner ears. [Financial support was provided by the National Science Foundation under Grant No. 234046.]
Sound localization by echolocating bats: Are auditory signals enough?
Authors: Aytekin Murat , Moss Cynthia F. , Simon Jonathan Z.
Published: September 2008

Echolocating bats localize objects by producing ultrasound vocalizations and listening to sonar returns. Interaural differences in the echoes arriving at the bats’ ears contribute to the process of object localization. The spatial properties of sonar emissions and the mobility of the head and pinna also contribute to the process of sound localization in bats. Measurements of sonar emission patterns from unrestrained, freely vocalizing bats have shown that sonar beam shape varies across individual vocalizations. Consequently, the bat auditory system needs to adapt its computations to accurately localize objects using changing acoustic inputs. Extra-auditory signals that carry information about pinna position and beam shape are required for auditory localization of sound sources. The auditory system must learn associations between extra-auditory signals (e.g., head and pinna position) and acoustic spatial cues. These demands on the nervous system suggest that sound localization is achieved through the interaction of behavioral control and acoustic inputs. A sensorimotor model that demonstrates how an organism can learn space through auditory-motor contingencies is presented. The model also reveals how different aspects of sound localization, e.g., experience-dependent acquisition, adaptation, and extra-auditory influences, can be joined under a comprehensive framework.
Training-induced improvements on interaural level difference (ILD) and interaural time difference (ITD) discrimination in human adults
Authors: Wright Beverly A.
Published: September 2008

The two primary cues to the location of sound sources on the horizontal plane are interaural level differences (ILDs) and interaural time differences (ITDs). The malleability of the processing of these two cues in humans was investigated by examining how multiday practice affects the discrimination of different values of ILDs and ongoing ITDs presented over headphones in adults with normal hearing. On average, the listeners improved on both ILD and ITD discrimination, but the learning patterns differed between the two cue types. Improvement was initially rapid for both cue types and appeared to generalize broadly across conditions, suggesting procedural learning. However, a subsequent slower-improvement stage occurred solely for the ILD cue and showed some specificity to the stimulus used during training. Interestingly, for ILD discrimination, both the best and worst daily threshold estimates decreased with multiday training, indicating an improvement in fundamental processing capacity. In contrast, for ITD discrimination, the best threshold estimates remained unchanged but the worst decreased, suggesting an increased ability to access already existing capacities. One interpretation of these data is that training mediates the processing of ILDs and ITDs at a stage in the auditory pathway, where these two cues are processed separately. [Work supported by NIH/NIDCD.]
Recovery from localization dominance in the barn owl
Authors: Nelson Brian S. , Takahashi Terry T.
Published: September 2008

Barn owls, like humans, localize sounds that arrive directly from a source and are less influenced by reflections that follow after a short delay. Neural responses in the owls’ auditory space map are diminished when a sound duration exceeds that of the reflection’s delay and firing recovers only when the delay exceeds ∼10 ms. Neither the onset- nor the ongoing-delay causes this diminishment. Instead, recovery corresponds with the emergence of a response at the stimulus end, when only the reflection is present. Head-saccades were measured while manipulating the duration of the reflection-alone sound segment. The proportion of saccades that each owl made toward the lagging source depended on the duration of the reflection-alone segment and was independent of the stimulus onset-delay. The perceptual salience of a reflection, or other lagging sound, may thus depend on the space map’s response to this reflection-alone segment. [Work supported by NIH, Grants F32 DC008267-01A1 to B.S.N and DC 03925.]
Why humpback whales learn songs: Courting or ranging?
Authors: Mercado Eduardo
Published: September 2008

Singing humpback whales within a population appear to continuously modify the content of their songs such that at any given time, most whales in a particular region are singing stereotypically-structured songs. This phenomenon is widely regarded as evidence that humpback whales learn songs from conspecifics, and is often cited as evidence that humpback whale songs are a reproductive acoustic display comparable to the songs of songbirds. An alternative possibility, however, is that humpback whales copy the songs of their neighbors because this maximizes their ability to passively or actively track the positions of other whales. In particular, comparing incoming sounds to memories of self-produced sounds may enhance a whale’s capacity to judge the distance that the sound has traveled by increasing the whale’s ability to identify degradation cues that vary systematically as a function of propagation distance. An increased capacity to accurately estimate the position of sound sources might in turn improve a whale’s ability to segregate songs when multiple singers are audible. This alternative perspective suggests that song learning by humpback whales is an adaptation for auditory spatial perception, rather than the result of sexual selection for a communal vocal display that increases the responsiveness of females.
Acoustic radiation patterns of mating calls of the túngara frog: Implications for multiple receivers
Authors: Bernal Ximena E. , Page Rachel A. , Ryan Michael J. , Argo Theodore F. , Wilson Preston S.
Published: September 2008

In its simplest form, communication is an interaction between a signaler and a receiver in which the signal has some probabilistic influence on the behavior of the receiver. For communication to proceed, the signal must be detected and perceived by the receiver; that is, the receiver must be within the active space of the signal. If patterns of sound radiation are not omni-directional, the position of the receiver relative to the sender is critical. In previous measurements of the horizontal directivity of mating calls of frogs and toads, the acoustic signals were analyzed using peak or RMS analysis [Gerhardt, J. Comp. Physiol. A 102, 1–12 (1975)] and the resulting broadband directivities ranged from negligible (omnidirectional) to a maximum of about 5 dB. We report new laboratory measurements of both the horizontal and vertical frequency-dependent directivity of the mating calls of túngara frogs (Physalaemus pustulosus). These band-limited directivities are significantly greater than broadband directivities, with a maximum directivity of 20 dB in the vertical plane for harmonics near 6 kHz. Ultrasonic frequencies, recently found in the calls of some frogs, are absent in the mating call of túngara frogs. The implications with regard to mating and predator-prey interactions are discussed.
Seismic investigation of natural methane hydrate deposits
Authors: Wood Warren
Published: September 2008

The world’s continental margins are home to the very high pressures and low temperatures where methane combines with water to form the ice-like methane hydrate. Only in the last couple of decades has it been discovered that methane hydrate is distributed over virtually every continental margin, as well as Arctic and Antarctic regions, and as such, may play a significant role as a future energy source, an agent of global climate change, or a factor in marine slope stability. Because the acoustic impedance of gas phase methane is significantly less than sediment, water, or methane hydrate, the phase boundary between gas and gas hydrate is frequently quite strong, and easily discernible in seismic sections. Further, because pressure variations in this part of the seafloor are typically small, the phase boundary can be used to determine sediment temperature. In certain circumstances, lateral variations in the depth to this phase boundary can be used to constrain the flux of heat, pore-water, and methane responsible for concentrated methane hydrate deposits and chemosynthetic communities found at seafloor seeps.
Synthetic aperture processing of reflection profiling data
Authors: Schock Steven
Published: September 2008

Chirp sonar data are processed using synthetic aperture processing to improve the spatial resolution and subsurface penetration of reflection profiles of the seabed. Synthetic aperture processing is implemented by calculating the vertical change in the positions of acoustic transducers between transmission and using the offsets to time shift the acoustic data so that reflectors are summed coherently. The changes in projector and hydrophone positions between successive transmissions are calculated based on Doppler velocity log and inertial measurement unit measurements of vehicle motion. The pulse repetition interval can exceed half-wavelength spacing by increasing the number of physical hydrophone channels. Imagery generated from reflection profiles of seabeds generated in several depositional environments are compared, and used to quantify the improvement in the spatial resolution and the SNR of reflection profiles as a function of the length of the synthetic aperture.
Chirp seismic reflection data on the New Jersey middle and outer shelf: The geologic response to 40,000 years of sea level change
Authors: Goff John , Austin James , Christensen Beth , Turgut Altan
Published: September 2008

Chirp seismic reflection data have been collected extensively on the New Jersey continental shelf in support of Office of Naval Research (ONR)-sponsored research. This composite data set includes surveys in 2001 and 2002 for the Geoclutter program, and in 2006 for the Shallow Water 06 program. Chirp uses a swept-frequency source (1–15 kHz), matched filtered to provide decimeter vertical accuracy and penetration up to 30 m in coarse-grained sediments. These data have been used to map out the complex shallow stratigraphy of this region, which includes: (1) a regional reflector formed about 40,000 years ago; (2) a layered shelf-edge wedge deposited during sea level fall; (3) fluvial channels formed at lowstand, and later filled with an estuarine sequence during sea level rise; (4) a ravinement surface created by shoreface erosion, which forms a lag of coarse material; and (5) the Holocene sand sheet, formed into sand ridges up to 10 m thick. Modern erosion has exposed many of the older units at or near the seafloor. Seabed sediments along acoustic propagation pathways are therefore highly heterogeneous. Vibracoring is planned for August, 2007. Analysis will include geoacoustic logging and geologic characterization. Preliminary results from these cores will also be presented.
Mobile parametric sub-bottom profiler system for shallow and medium depth applications
Authors: Wunderlich Jens
Published: September 2008

Sub-bottom profilers based on parametric acoustics offer many advantages, especially for applications with the focus on high resolution. They have a narrow beam in spite of small transducers and virtually no side lobes. They transmit very short sound pulses at high pulse repetition rates. Excellent vertical, as well as horizontal, resolutions at reasonable penetrations are proven benefits by using this technique. Electronic steering of focussed sound beams allows the compensation of movements of the survey platform. The paper presents a parametric system with low frequencies in the range of 4 kHz to 15 kHz. The transducer has an active area of 22 cm × 22 cm only and provides a stabilized sound beam of less than 4 deg. Such small size and no need for an additional receiver gives high mobility for the operation on different platforms. Sound beam stabilization guarantees the operation from offshore vessels under ocean conditions. Due to a special transmit regime, high ping rates of up to 30 pings per s are maintained, independent of water depth. Some more design parameters will be discussed and illustrated, with results from shallow water and offshore applications.
Extrapolation of geoacoustic properties using seismic reflection data: A shallow water example
Authors: Holland Charles W. , Lowrie Allen , Dettmer Jan , Dosso Stan E.
Published: September 2008

In areas of the world that are bottom limited, sonar performance models require accurate seabed geoacoustic properties. Geoacoustic properties, e.g., sound speed, density, and attenuation as a function of depth, frequency and geographic position, are expensive to acquire over large areas. Most geoacoustic techniques, including direct sampling (e.g., cores, probes) or acoustic inversion methods (e.g., matched field methods) spatially sample either in 1-D or 2-D. Conducting these measurements in a dense grid over large areas is not feasible and as a consequence seabed database developers rely on seismic reflection data coupled with geologic models to spatially interpolate and extrapolate the geoacoustic properties. Seismic reflection data is attractive for this purpose because it has much greater geographic coverage and contains information on underlying geologic processes that ultimately control the geoacoustic properties. The inherent strengths and weaknesses of seismic data for geoacoustic extrapolation are explored using seismic reflection transects in the Straits of Sicily together with ground-truth geoacoustic properties and their uncertainties (from wide-angle reflection measurements) at each end of the transect. The uncertainties of the extrapolated geoacoustic properties are determined with and without the ground-truth data. [Work supported by the Office of Naval Research OA321 and the NATO Undersea Research Centre.]
Meteorological instrumentation for infrasonic wind noise studies
Authors: Raspet Richard , Webster Jeremy
Published: September 2008

Recent research on the prediction of wind noise contributions from the measured turbulent velocity spectrum has led to a better understanding of what meteorological variables are necessary to analyze and compare wind noise measurements on infrasound arrays. In this talk, we will describe the variables necessary to correlate different contributions to the pressure spectrum, depending on the sensor configuration and arrangement. The instrumentation necessary to study surface pressure fluctuations on wind screens, the intrinsic turbulence-turbulence pressure fluctuation, the mean shear-turbulence fluctuation pressure, and the surface pressure fluctuations above flat surfaces will be discussed. The case of elevated shears above vegetation layers is particularly important to infrasound arrays. A theoretical investigation has identified what meteorological parameters must be evaluated in order to compare theory to measurement. [Research supported by the U.S. Army TACOM-ARDEC at Picatinny Arsenal, NJ.]
Decoupling of seismic and infrasonic sources based on the orientation of a low-frequency electret condenser microphone
Authors: Shams Qamar A. , Zuckerwar Allan J. , Binger Lloyd W. , Stoughton John W.
Published: September 2008

Membrane-based microphones are subject to seismic excitation, which interferes with signals from propagating infrasound. An experiment was designed to decouple seismic and infrasonic signals. The microphone was rigidly attached to a base plate on the ground with a fixture that permitted the orientation of the microphone axis to be varied. An accelerometer was mounted to respond to seismic stimuli normal to the base plate. Subsequent field testing included the dropping of various weights from a height of 2–3 m vertical drop at distances of 2 to 15 m from the system. In addition, a low frequency Helmholtz resonator (17 Hz) was used to provide an acoustic test signal. The intent of the experiment was to identify the best microphone orientation to reduce the effects of local seismic disturbances in the presence of low-frequency acoustic monitoring. Additional experiments were performed in the laboratory using a vibration exciter. The results of decoupling of seismic and infrasonic sources, based upon laboratory and field experiments, will be presented.
Sources of background noise in low-frequency condenser microphones
Authors: Zuckerwar Allan J. , Shams Qamar A. , Cooper Jeremy A.
Published: September 2008

The background noise of a condenser microphone originates from external sources (electromagnetic interference, vibration) and internal sources (self-noise). The leading internal sources include the membrane damping resistance, the polarization voltage resistance (air condenser microphone only), the input resistance to the preamplifier, the capillary vent resistance, and a source of 1/f noise. These sources are modeled in a noise-equivalent circuit, from which an expression for the noise power spectral density is derived. This expression is compared to measurements on a low-frequency electret condenser microphone taken in an acoustic isolation vessel. The capillary vent and 1/f noises vary inversely with frequency and, thus, impact the background noise levels in the infrasonic region.
Preparing and retaining high quality science and mathematics teachers: Research, programs and results
Authors: Gillespie Nicole
Published: September 2008

A growing body of research is revealing that the much-publicized lack of sufficient high-quality teachers in U.S. schools is a problem of retention rather than insufficient production, particularly in the case of secondary math and science teachers. Across all subjects, nearly 50% of teachers tend to leave the profession within the first 5 years of beginning teaching, so the attrition problem appears to be one of novice teachers rather than veterans. Furthermore, there is a common assumption in the U.S. that math and science teachers leave at a higher rate than teachers of other subjects because more, and more lucrative, career opportunities are available to individuals with science and math backgrounds. In response to a growing need for highly effective math and science teachers, the Knowles Science Teaching Foundation (KSTF) provides 5-year teaching fellowships to beginning secondary mathematics and science teachers across the United States. In this presentation, I will discuss the structure and rationale of the fellowship in light of national trends in math and science teacher qualifications, effectiveness and retention as well as preliminary results of the fellowship program evaluation research.
Teachers in industry: A model for K-12 professional development
Authors: Harpole Sandra H.
Published: September 2008

The Center for Science, Mathematics and Technology (CSMT) at Mississippi State University, with funding from the National Science Foundation and the Appalachian Regional Commission, has developed a model for professional development that utilizes industry-education partnerships, critical in educating students to enable them to compete for jobs in today’s knowledge-based economy. Through quality learning experiences that result from research/industry experiences, teachers can better prepare students for the 21st century workforce, become more aware of career opportunities, and emphasize to their students the importance of preparation in science, technology, engineering, and mathematics. Professional development programs offered by the CSMT focus on utilizing partnerships to bridge the gap between the classroom and the workplace by placing K-12 teachers in industry to learn the relationship between academic content and real world applications, as well as the basic skills and competencies required by employers. Components of successful CSMT professional development programs include multi-year summer workshops providing industry experience, academic year follow-up sessions, and local industry internships. Partner industries include Northrop Grumman Ingalls Ship Systems, Tennessee Valley Authority, North American Coal, Nissan, and Stennis Space Center, as well as a number of industries located in participants local area. [Work is supported by NSF and ARC.]
Issues of equity in physics access and enrollment in New York City public high schools
Authors: Kelly Angela
Published: September 2008

Despite reports to the contrary, the availability of physics as a course for high school students is not equitably distributed throughout the U.S. While some schools provide physics for all, a more common scenario is limited availability, often open only to the relatively few students who have completed the necessary prerequisites or are deemed capable of understanding physics. Some schools do not offer physics at all. This is particularly true in urban districts, where science resources and instruction are chronically inadequate. This study looks at the access to and availability of physics courses for high school students in New York City. The schools were surveyed to determine where physics was offered and how many students were enrolled in the course. Statistics were performed to compare differences between schools that offered physics and those that did not. Additionally, factors were examined that relate to physics availability, such as the magnet school configuration, the AP Physics option, science curricular sequence, and the conceptual physics option. Overall, it was determined that physics availability is very limited in NYC schools, a serious inequity that disproportionately affects students of color and poor children. Strategies for improving access and enrollment will be discussed.
Revising New Mexico’s science standards in 2003
Authors: Dogruel Sharon B. , Sánchez Steven A. , Swift Gregory W.
Published: September 2008

Partly in response to the No Child Left Behind Act of 2001, most states use ‘‘standards’’ to guide the creation of K–12 curriculum in school districts. The authors of this talk were centrally involved in the 2003 revision of New Mexico’s science standards. According to the Fordham Foundation’s 2005 review of 50 state science standards, the 2003 revision took New Mexico’s standards from among the worst in the nation to seventh best. Summarizing that revision, this talk will challenge the audience to consider what every American should know about physical acoustics, science, and scientific methods, and how government-established standards for K–12 education can support such goals. Examples of the relationship between core science standards and specialized subjects, such as acoustics, will be given, and the measurable effect of standards-based curriculum development on student achievement in one New Mexico school district will be described. The influence of those who mix science and religion will also be discussed, with particular attention to testable hypotheses in science and to lessons learned while revising the New Mexico science standards.
Introduction of therapeutic ultrasound projects into undergraduate biomedical engineering curriculum at the George Washington University
Authors: Zderic Vesna
Published: September 2008

Therapeutic ultrasound examples and projects have been successfully incorporated in both formal classes and undergraduate research at the George Washington University. Topics appropriate for various levels of experience and knowledge had to be carefully selected. These included: General demonstrations for summer high school students from local public schools, well-defined sophomore research projects, and finally capstone projects that focus on device design and development. Demonstrations of therapeutic ultrasound ranged from application of high-intensity focused ultrasound (HIFU) to make precise holes in plastic containers and cook meat (showing thermal effects), to production of water fountains (showing streaming effects) and production of dancing (standing wave pattern) bubbles that outline the shape of focus (showing cavitation effects). While very entertaining for younger students, these demonstrations also allow an explanation of basic ultrasound theory and potential clinical applications. Some examples of sophomore research in the therapeutic ultrasound area are: Ultrasound-enhanced delivery of ocular antibiotics, HIFU treatment of deep seated tumors, and studying effects of the presence of air or bone in the post-focal HIFU region. Examples of capstone projects include: Portable ultrasound driving system, cooling system for HIFU transducers, robotic HIFU control, flow phantom for testing of ultrasound-guided HIFU treatments, and system for measurements of ultrasound powers.
Active music listening interfaces based on sound source separation and F0 estimation
Authors: Goto Masataka
Published: September 2008

This paper describes research aimed at building ‘‘active music listening interfaces’’ to demonstrate the importance of music understanding technologies, including sound source separation and F0 estimation, and the benefit they offer to end users. Active music listening is a way of listening to music through active interactions. Given polyphonic sound mixtures taken from available music recordings, our active music listening interfaces enrich end-users’ music listening experiences. For example, by suppressing drum sounds and adding other drum sounds, Drumix [Yoshii et al., IPSJ Journal, 48(3), (2007)] enables a user to change the volume and timbre of drum sounds separated from the mixtures and rearrange rhythmic patterns of these drum sounds during playback. In addition, during the playback of a song, LyricSynchronizer [Fujihara et al., Proc. of IEEE ISM 2006] displays scrolling lyrics and highlights the phrase currently sung. Because lyrics are automatically synchronized with vocal melodies (separated from polyphonic sound mixtures using our predominant-F0 estimation method PreFEst), a user can easily follow the current playback position and click on a word in the lyrics to listen to it. These interfaces can also be regarded as ‘‘augmented music-understanding interfaces’’ that facilitate deeper understanding of music by end users.
Timbre modeling for the purpose of sound source recognition and separation in music
Authors: Klapuri Anssi
Published: September 2008

Timbre models of musical instruments were studied in order to recognize sound sources in music and to organize sounds to their sources. The log-power spectrum of the sounds was modeled using a combination of linear bases, one defined as a function of frequency, and another as a function of harmonic index. Algorithms for initializing, learning, and sequentilly adapting this model are described. In simulations, the model had a benefit over conventional Mel-cepstral representations, especially in the case of certain instruments, including the electric guitar, the organ, the mallet percussions, and the clarinets. The improvement was observed in supervised instrument classification, but not so clearly in the unsupervised clustering of sounds.
A framework for sound source separation using spectral clustering
Authors: Tzanetakis George , Lagrange Mathieu , Martins Luis Gustavo , Murdoch Jennifer
Published: September 2008

Clustering based on the normalized cut criterion, and more generally, spectral clustering methods, are techniques originally proposed to model perceptual grouping tasks, such as image segmentation in computer vision. In this work, it is shown how such techniques can be applied to the problem of dominant melodic source separation in polyphonic music audio signals. One of the main advantages of this approach is the ability to incorporate mutiple perceptually-inspired grouping criteria into a single framework without requiring multiple processing stages, as many existing computational auditory science analysis approaches do. Experimental results for several tasks, including dominant melody pitch detection, are presented. The system is based on a sinusoidal modeling analysis front-end. A novel similarity cue based on harmonicity (harmonically-wrapped peak similariy) is also introduced. The proposed system is data-driven (i.e., requires no prior knowledge about the extracted source), causal, robust, practical, and efficient (close to real-time on a fast computer). Although a specific implementation is presented, one of the main advantages of the proposed approach is its ability to utilize different analysis front-ends and grouping criteria in a straightforward manner.
Algorithm for separating vocals from polyphonic music
Authors: Virtanen Tuomas , Ryynänen Matti
Published: September 2008

An algorithm for the separation of vocals from polyphonic music is described. The algorithm consists of two stages, which first estimate the predominant melody line, and then the sinusoidal modeling parameters corresponding to the melody line. The melody line is estimated using a hidden Markov model where the output of a multiple fundamental frequency estimator is used as a feature set. The states of the hidden Markov model correspond to musical notes having different fundamental frequencies, and the state transition probabilities are determined by a musicological model. The sinusoidal modeling stage estimates the frequency, amplitude, and phase of each overtone of the predominant melody line in each frame. The sinusoidal modeling stage can also include mechanisms which reduce the effect of interfering sound sources on the estimated parameters. The resulting separation algorithm is independent of singer identity, musical genre, or instrumentation. Simulation experiments on real polyphonic music show that the algorithm enables separation of vocals from the accompaniment, providing robust results on various musical genres.
Separation of singing voice from music accompaniment for monaural recordings
Authors: Li Yipeng , Wang DeLiang
Published: September 2008

Separating singing voice from music accompaniment is useful in a wide range of applications, such as lyrics recognition and alignment, singer identification, and music information retrieval. Compared to speech separation, which has been extensively studied for decades, singing voice separation has been little explored. We have developed a pitch-based system to separate singing voice from music accompaniment for monaural recordings. Our system consists of three stages. The singing voice detection stage partitions and classifies an input into vocal and nonvocal portions. For each vocal portion, the predominant pitch detection stage detects the pitches of the singing voice. Finally, the separation stage uses the detected pitch to group the time-frequency segments of the singing voice. Quantitative results show that the system performs the separation task successfully. [The work is supported by AFOSR and AFRL.]
Statistical models for music signal analysis and transcription
Authors: Cemgil A. Taylan
Published: September 2008

In recent years, there has been an increasing interest in statistical approaches and tools from machine learning, for the analysis of audio and music signals. The application of statistical techniques is quite natural: Acoustical time series can be conveniently modeled using hierarchical signal models by incorporating prior knowledge from various sources: From physics or studies of human cognition and perception. Once a realistic hierarchical model is constructed, many audio processing tasks, such as coding, restoration, transcription, separation, identification, or resynthesis can be formulated consistently as Bayesian posterior inference problems. This contribution illustrates various realistic generative signal models for audio and music signal analysis. In particular, factorial switching state space models, Gamma-Markov random fields, and point process models will be discussed. Some models admit exact inference, otherwise, efficient algorithms based on variational or stochastic approximation methods can be developed. We will illustrate the approach on music transcription, restoration, and source separation applications. [Work supported by EPSRC.]
Employing the mutual phase coherence of the overtones in musical sounds for audio source separation and reconstruction
Authors: Velikic Gordana , Bocko Mark F.
Published: September 2008

Source separation from a monaural mixture of musical sounds is challenging. When only a single mixture of multiple sources is available, the method of independent component analysis may not be straightforwardly applied, and proposed source separation methods have relied on previous knowledge of the independent sources. Our method employs mutual correlations of the overtone phases of musical sounds to ascribe spectral features to individual sources. The phase versus time is computed from the analytical signal representation of the output of a set of adaptive band-pass filters that perform initial spectral separation. A small number of cleanly separable partials, usually the fundamentals, are then employed as references to which the remaining filter-bank outputs are correlated. To separate overlapping spectral features and ascribe the proper amount of power to each source, the phase of the reference signal is scaled to the harmonic frequency, and the amplitude of each overtone is estimated by computing the cross-correlation of the phase trajectories. To group sonic events in time, we employ the history of the signal itself, thus eliminating the need for prior information. We discuss this separation method and the audio quality of the reconstructed source signals, with examples and a quantitative perceptual metric.
A standard way of measuring rainfall noise
Authors: Peppin Richard J. , Coffeen Robert C.
Published: September 2008

About 10 years ago at an ISO TC 29 meeting, the concept of the measurement of rainfall noise was suggested. At the time it made no sense to me. Who cares about this? Not me, since I liked the sound of rain on my roof, and the louder the better. The concept was to evaluate roofs to assess the insulation capabilities from sound (vibration?) produced by rainfall. But in spite of my skepticism, wiser heads prevailed, and in the end, the approach was drafted into a work item, a draft, and a final draft standard. This paper is a summary of ISO FDIS 140-18, ‘‘Acoustics—Measurement of sound insulation in buildings and of building elements—part 18: Laboratory measurement of sound generated by rainfall on building elements.’’ I discuss the equipment needed, the test method, and the uncertainty.
Waterfall noise
Authors: Lilly Jerry
Published: September 2008

Noise generated by natural and man-made waterfalls is of considerable interest to acoustical consultants, who are looking for reliable sources of outdoor masking noise. Being able to estimate noise levels from water features prior to construction is also important. This presentation discusses field measurements taken at waterfalls with flow rates ranging from 0.2 to 20,000 cubic ft per s and drop heights ranging from 1 to 270 ft. Octave band spectra and time variations will be shown. Empirical expressions for estimating octave band and A-weighted sound power levels will also be presented.
Characterization of a large volume spherical resonator for studies of acoustically induced cavitation in liquids
Authors: Raymond Jason L. , Bader Kenneth , Mobley Joel , Gaitan D. Felipe , Hiller Robert A. , Tessien Ross A.
Published: September 2008

This paper describes a spherical acoustical resonator system used to study acoustic cavitation phenomena in liquids as part of an effort to scale up the energy density of collapse of transient cavitation. The resonator is formed by a stainless steel spherical shell 24.1 cm in diameter (OD) and either 1.27 cm or 1.90 cm thick designed for generating transient cavitation at high static pressures. An external transducer attached to the surface of the resonator was used to excite an acoustic standing wave in the liquid in order to generate a pressure maximum near the center of the liquid. We will present the results of our characterization of this device, including hydrophone measurements of the acoustic pressure generated in the liquid and vibration analysis on the surface of the resonator carried out using laser Doppler vibrometry. The resonance frequency spectrum and modal structure are compared to numerical predictions using theory developed by (Mehl, JASA 78(2), 782–788 (1985)) [Work supported by SMDC Contract No. W9113M-07-C-0178.]
Computer simulations of cavitation collapses at high static pressure using hydrocode HYADES: Plasma conditions and shock waves in the liquid
Authors: Gaitan D. Felipe , Tessien Ross A. , Hiller Robert A. , Alstadter Jeff
Published: September 2008

Previously (JASA 121 pt.2, p. 3181) transient cavitation in high pressure spherical resonators was described. The phenomenon is characterized by cavitation events lasting a few ms (100 s acoustic cycles) in which a cavity (or cavities) collapse violently, emitting flashes of light of widths ∼1–40 nsec and spherical shock waves with amplitudes ∼1–100 bars (depending on the static pressure) at a distance of 10 cm from the collapse. Both SL and shock amplitudes are proportional to the static pressure. The goal of these experiments is to investigate how the static pressure increases the intensity of acoustic cavitation collapse and whether thermonuclear fusion reactions are possible this way. The determination of plasma temperatures, pressures, and densities is therefore critical in making progress. Furthermore, the amplitude and velocity of the shock waves can be used to determine the conditions at stagnation (end of collapse), assuming the cavity size at that time is known. To this end, results of numerical simulations using HYADES plasma physics hydrocode will be presented, with emphasis on the plasma conditions versus the amount of gas in the cavity and the static pressure, as well as the amplitude and velocity of the outgoing shock waves generated after the collapse [Work supported by SMDC Contract No. W9113M-07-C-0178.]
Time of flight measurements for strong shocks emitted from transient cavitation in 300 bar resonator
Authors: Tessien Ross A. , Schaefer James , Hiller Robert A. , Gaitan D. Felipe , Tardif Henry
Published: September 2008

The behavior of shocks emitted from transient cavitation in acoustic cavitation systems with static pressures up to 300 bar is explored using photomultiplier tubes, hydrophones, Schlieren, and Shadowgraphic methods. Shocks emitted from strong implosions travel initially at supersonic velocities, leading to a shortening of the time of flight (TOF) from implosion site to detector as compared to sound speed motions. A larger difference between expected sonic and actual supersonic translation times is indicative of higher stagnation pressures. Experimental results are indicative of possible stagnation pressures in the Mbar range and place constraints on computer models. [Work supported by SMDC Contract no. W9113M-07-C-0178.]
Morphology of transient cavitation in 300 bar resonator
Authors: Tessien Ross A. , Tardif Henry , Hiller Robert A. , Schaefer James , Gaitan D. Felipe
Published: September 2008

Details of the observed evolution of a high pressure transient cavitation event are described. The combination of photomultiplier tubes, hydrophones, fiber optic hydrophone, laser to photo diode light blocking methods are used to explore the evolution of a transient bubble cloud event from ns to ms time scales. [Work supported by SMDC Contract No. W9113M-07-C-0178.]
Acoustic and vibratory emissions from bubbles collapsing near boundaries
Authors: Manzi Nicholas J. , Geary Sean , Squires Allison , Chitnis Parag V. , Cleveland Robin O. , Holt R. Glynn , Roy Ronald A.
Published: September 2008

The collapse of transient bubbles in the vicinity of a boundary was investigated. Transient bubbles were created using a focused laser, and a shock-wave lithotripter. Two boundary types were investigated, rigid and smooth, and rigid and porous. The porous boundary was either gas-saturated, or actively bubbling. Acoustic emissions from the collapsing transient bubbles were measured with a hydrophone. Boundary vibrations were (in some cases) measured using a laser vibrometer. Images of the collapse were also obtained from a high-speed camera. These diagnostics were used to investigate the threshold for and dynamics of the well-known asymmetric jetting collapse of a bubble near a boundary, by varying the distance of the bubble from the boundary. The possibility of using an acoustic or vibration-based measurement as a diagnostic for boundary damage from bubble collapse is considered. [Work supported by ORNL.]
Resonant bubble effects in void fraction measurements from modal frequencies of a bubbly impedance tube
Authors: Ormonde Christopher E. , Cohen Seth B. , Chitnis Parag V. , Cleveland Robin O. , Roy Ronald A. , Holt R. Glynn
Published: September 2008

The effects of resonant bubbles on the measurement of void fraction in a cylindrical waveguide are examined. Air bubbles are introduced into a steel cylindrical waveguide containing a Xanthan gum gel. The frequency response of the system is obtained. Sound speeds are inferred by assuming a linear dependence of axial mode number on mode frequency, and void fractions are calculated assuming a mixture sound speed for a bubble population much smaller than the resonant sizes in the modal frequency range (Woods limit). Results from experiments with various bubble sizes and varying number of bubbles are presented, including single bubbles, two differently sized bubbles, and multiple bubbles of roughly the same size. Local dispersion effects are exhibited in the region of bubble resonance for bubbles that are large enough to violate the Woods limit assumption. The effect of such rogue bubbles on the accuracy of the void fraction measurement in a system with unknown bubble size is considered. [Work supported by ORNL.]
Acoustic phase speed measurements in a bubbly liquid
Authors: Cheyne Stanley A. , Hembree Robert H.
Published: September 2008

Acoustic phase speed measurements of a bubbly liquid have been made using hydrophones. Standing wave and time-of-flight methods were used in both a cylindrical tube and a larger tank. A standing-wave technique similar to [Silberman, J. Acoust. Soc. Am. 29 (1957)] was used to measure sound velocity at low void fractions (<2%). Above 2% the bubble size distribution was not uniform, making it more difficult to get reliable results. Bubble clouds were produced using a variety of arrays of hypodermic needles.