bluuebunny/crossref_metadata_2025 huggingface dataset:
Random matrix theory for modeling random uncertainties in transient elastodynamics
Authors: Soize Christian
Published: February 2014

A probability model for symmetric positive-definite real random matrices is constructed using the maximum entropy principle which allows only the available information to be used. The result obtained differs from the known results concerning Gaussian and circular ensembles for random matrices. The probability distribution of such a random matrix and the probability density function of its random eigenvalues are explicitely constructed. A fundamental mathematical result concerning convergence properties as the dimension of the random matrix approaches infinity is presented. An algebraic representation of the probability model has been obtained and is very well suited to Monte Carlo numerical simulation. This random matrix theory is used to construct a new nonparametric method for modeling random uncertainties in transient elastodynamics. The information used does not require the description of the local parameters of the mechanical model. The available information is constituted of the algebraic properties related to the generalized mass, damping and stiffness matrices which have to be positive-definite symmetric matrices, and the knowledge of these matrices for the mean reduced matrix model. The fundamental properties related to the convergence of the stochastic transient response in elastodynamics is analyzed. Finally, an example is presented.a)Present address: Ing. 2000, Bat. Copernic, Univ. de Marne-la-Vallée, 5 Bd. Descartes, 77454 Marne-la-Vallée, France.
Irreversible energy transfer and distribution in complex systems
Authors: Akay Adnan , Carcaterra Antonio
Published: February 2014

This presentation examines the conditions under which irreversible energy transfer or irreversible energy redistribution can take place within dynamical systems that do not possess classical damping properties. Under usual circumstances, energy input to a system returns to its original form after a delay during which the system components undergo oscillatory motions. However, depending on the complexity of the system, the period during which energy travels within the system may become very large, reaching infinity. While conditions that lead to irreversible energy transfer in linear systems are rare, nonlinearities in the system can more readily provide continuous absorption of energy as in the case of thermalized vibrations of atoms. Numerical simulations suggest that the irreversibility attribute for a given system is deeply related to the observation time scale. Examples show that a process may appear reversible when its instantaneous energy time history is observed while its time-average trend exhibits irreversibility. By introducing entropy as a measure of the irreversibility associated with the energy transfer, this presentation suggests three controlling parameters of irreversibility: system complexity as measured by the number of its degrees of freedom, the effect of nonlinearities, and the time-average observation scale. An analysis of their interrelationships discloses new insights into the thermalization phenomenon. [Research sponsored by NSF and INSEAN.]
Interlanguage benefit for non-native speaker intelligibility
Authors: Bent Tessa
Published: February 2014

Non-native speakers (NNSs) of English must often communicate in English even if they share an L1. This study investigated how the talker–listener match with respect to language background affects L2 intelligibility. Two non-native speakers of English with an L1 of Chinese and two monolingual English speakers were recorded in English reading sentences and producing spontaneous speech. Listeners were 32 monolingual native speakers of English, 18 NNS of English with an L1 of Chinese and 14 NNS of English with an L1 other than Chinese. Results showed patterns of objective intelligibility and subjective comprehensibility ratings across listener groups that were strongly influenced by the relationship between the language backgrounds of talker and listener. As expected, native English listeners showed a preference for the native English talkers over either of the Chinese talkers. In contrast, the Chinese listeners found one of the Chinese talkers most intelligible, and the non-Chinese non-native listeners found one of the Chinese talkers equally intelligible to one of the native talkers. From these patterns of intelligibility, we conclude that, provided the talker is above a certain threshold of intelligibility, if talker and listener both share an interlanguage or are both native speakers, intelligibility is maximized.
Training /v/–/w/ perception with native speakers of Indian languages
Authors: Aravamudhan Radhika , Schmidt Anna Marie
Published: February 2014

Experiments in training listeners to perceive non-native categories are an important aspect of cross-language perception research. In this study, ten native speakers of various Indian languages participated in training designed to improve perception of the English /v/–/w/ contrast using a fading technique (Jamieson and Morosan, 1986). First the subjects labeled English /p, b, f, v, w/ using native language (L1) orthography to ensure that other L1 consonants were not evoked by acoustic cues to English /v/, /w/. They also rated the closeness of the English sound they heard to the sound in their L1. In the five-day training, subjects heard natural stimuli produced by four (two males and two females) English speakers. The steady-state portion of the initial consonant was reiterated by varying amounts with subjects hearing progressively shorter consonants as the training progressed. Both discrimination and identification training with feedback were used. Pre- and post-training testing with stimuli from new speakers as well as recording of production of Indian subjects was completed. Results and implications will be discussed.
Perceptual and acoustical similarity of six European languages
Authors: Stockmal Verna B. , Bond Zinny S.
Published: February 2014

Listeners have shown considerable sensitivity to the ‘‘acoustic signature’’ or ‘‘sound’’ of languages when discriminating or identifying unknown foreign languages. Which acoustic/phonetic properties of languages listeners employ when making these judgments are only imperfectly understood. Bond and Stockmal [Acoust. Soc. of Am. Berlin (1999)] found that initially, listeners made judgments about Asian languages based on regional characteristics, what might be termed voice setting [J. Esling and R. Wong, TESOL Q. 17, 89–95 (1983)], rather than by rhythmic properties. Perceptual focus shifted and rhythm became more salient when the set of languages shared regional characteristics. At least some of the rhythmic properties of languages can be extracted by phonetic measurements of the acoustic signal [F. Ramus, M. Nespor, and J. Mehler, Cognition 73, 265–292 (1999)]. This study presents instrumental measurements based on consonant/vowel segmentation of six European languages, Bulgarian, Czech, Greek, Hungarian, Italian, and Romanian. The acoustical measurements were used to plot the relationship of the languages to one another. Listeners were asked to judge similarity of spoken samples of the languages and to indicate which salient feature of the language was the basis for each judgment. Comparison of the perceptual judgments and instrumental measurements was made.
Acquisition of dialectal differences in English by native Japanese speakers
Authors: McGory Julie , Frieda Elaina , Nissen Shawn , Fox Robert A. , Friedman Kelly , Rosenbauer Kim
Published: February 2014

Many previous investigations of second language (L2) learning have focused on the acquisition of phonetic segments by groups of non-native speakers living in diverse regions in the US. These studies have not, however, assessed possible dialectal variation in L2 productions. The current study investigates the extent to which dialectal differences found in the vowel systems of two different American English (AE) dialects are acquired by adult Japanese speakers. Four subject groups were identified: native English speakers of a midwestern dialect of AE, native English speakers of a southern dialect of AE, Japanese speakers whose target language is a midwestern AE dialect, and Japanese speakers whose target language is a southern AE dialect. Subjects were recorded saying word and nonword utterances in isolation. Acoustic measures of vowels that can potentially capture differences between the dialects were made. These include vowel duration, and F0, F1, F2, and F3 frequencies measured at five equal distances throughout the vowel. F0–F3 measurements were used to calculate bark differences. Preliminary findings suggest that adult Japanese learners acquire some of the acoustic properties that are consistent with the dialect of the target language. [Work supported by an INRS Award from research funding from ATR (Fox, P.I.).]
Emphatic Koreans and neutral Americans?
Authors: Kim Soohee , Curtis Emily , Carmichael Lesley
Published: February 2014

Intonation is one of the subtle grammatical aspects of a second language that often escapes formal instruction and thus acquisition. If intonation is acquired early on in first language, and no formal instruction is received, speakers are likely to carry over native language intonation patterns in a second language. The neutral intonation pattern for indicative sentences may differ across languages, for example. It is hypothesized that the neutral intonation pattern of the Seoul dialect (mid-high–low–high-low) is carried over to English by native speakers of Korean. It so happens that mid-high–low–high is an intonation contour that expresses emphasis or dissatisfaction in English, often resulting in perception of unintended emotion or inappropriate conversational implicature on Korean speakers’ part. To test our hypotheses, five native Seoul dialect speakers’ intonation contours in five statements are compared in both English and Korean. Koreans’ English productions are also rated for emotionality by 10 native speakers of English. Rules of intonation are an integral part of the grammar of a language and should be explicitly taught to learners of a second language, especially where their grammatical (or pragmatic) import differs.
Lexical tone contrast effects related to linguistic experience
Authors: Francis Alexander L. , Ciocca Valter
Published: February 2014

Listeners’ auditory discrimination of vowel sounds depends in part on the order in which stimuli are presented (Cowan and Morse, 1986). Such contrast effects have been argued to be language-independent (Polka and Bohn, 1996), and to result from psychophysical (not speech- or language-specific) order-of-presentation effects such as decay of memory traces over time or increased weighting of later-occurring stimuli (Macmillan, Braida, and Goldberg, 1992; Repp and Crowder, 1990). In the present study, native Cantonese speakers’ discrimination of a linguistic tone continuum is shown to exhibit contrast effects similar to those shown for vowels in previous studies. When presented with two syllables differing in F0 by approximately 4 Hz, listeners were significantly more sensitive to this difference when the first syllable was higher in frequency than the second. However, American English-speaking listeners with no experience listening to Cantonese showed no such contrast effect when tested in the same manner using the same stimuli. Neither English nor Cantonese listeners showed any contrast effects in the discrimination of a nonspeech continuum with the same frequency properties. These results suggest that tone contrast effects, unlike vowel effects, may be language-specific and not merely the consequence of general properties of auditory processing.
Modality salience in multimodal speech perception under degraded presentation conditions
Authors: Weisenberger Janet M. , Kreidler Sandra M. , York Katherine L. , Yeary Michelle A.
Published: February 2014

Studies of the McGurk effect in auditory-visual speech perception have demonstrated that both modalities contribute to the overall percept, even when both modalities are perfectly rendered. Initial studies in our laboratory found that a McGurk-type effect can also be observed with tactile-visual presentation, employing a tactile speech perception device. The present study investigated the question of whether subjects’ relative reliance on a particular sensory modality could be shifted when presentation via one modality was degraded. Subjects were tested with a McGurk paradigm in unimodal (visual, auditory, or tactile) and multimodal presentations, in both nondegraded and degraded presentation conditions. Auditory degradation was achieved by low-pass filtering with cutoffs at 400 or 1000 Hz, and visual degradation was achieved by use of a diffusing screen placed in front of a video monitor. Tactile stimuli were not degraded. Results showed that subjects quickly shifted response patterns when one modality was degraded to show increased reliance on the nondegraded modality. However, increased reliance on the nondegraded tactile input was not found, possibly because the initial training with the tactile device was limited. Nonetheless, tactile-visual McGurk effects were replicated. [Portions of this work were supported by NIH.]
Blind multichannel decision-feedback equalization of precoded OQPSK signals
Authors: Waldhorst Andreas , Weber Rolf , Böhme Johann F.
Published: February 2014

A new special modulation format is derived from Offset Quadri-Phase Shift-Keying (OQPSK) and is applied to high data-rate acoustic digital transmission in very shallow water. A novel multichannel receiver structure for this signal type is introduced. It is based on an adaptive decision feedback equalizer (DFE), which is extended so that both its feedforward and feedback sections are allowed to operate fractionally spaced. This is accomplished by exploitation of the special properties of the introduced modulation format at the receiver’s decision device. To compensate for Doppler effects, explicit feedforward timing and decision-directed carrier recovery are performed. This together enables the receiver to operate in a completely self-recovering or blind manner, which is verified by analyzing experimental data gathered in the North Sea during the ROBLINKS 1999 experiments. To demonstrate the good performance of the proposed blind receiver, results of successful data recovery after transmission over a few kilometers through shallow water in cases with both a fixed and a moving source are given. [Work supported by the European Commission.]
Ease of hearing in various classroom geometries
Authors: Stefaniw Abigail
Published: February 2014

There are many proposed standards by various organizations for classroom acoustics. However, none of these acoustical professionals include architectural designs that would make their criteria appear pragmatic to architects. This paper will summarize current research on classroom acoustics, and further it by linking it to geometrical acoustics. Current classroom standards can be condensed into three settings for three criteria: reverberation time, signal-to-noise ratio, and background-noise level. Each of these settings will be auralized in three different geometries for elementary school classrooms. The auralization will be used to administer intelligibility tests and ease of hearing tests to trained listeners. The ease of hearing questions will measure the concentration effort required to achieve intelligibility. This information will allow an architecturally realistic evaluation of the best acoustic geometry needed for high-intelligibility speech communication in learning spaces.
Acoustic design of the Charles R. Drew Charter School media center—a case study
Authors: Ehnert Jesse J.
Published: February 2014

The new Charles R. Drew Charter School in the East Lake community of Atlanta, GA, slated to open in August 2001, is a privately managed public school focusing on mathematics and reading for grades K–8. In addition to several classrooms, music rooms, laboratories, offices, and a cafetorium, the project includes a media center and reading area which share a common volume with the school’s main entrance lobby. Primary concerns in the design included providing adequate sound isolation for the various spaces within this common volume, ensuring suitably low background noise levels from the HVAC system, and providing high levels of speech intelligibility in the reading area. Designing to these goals while keeping the various areas all within the same space posed unique challenges to the design team. An iterative and collaborative design effort, which included computer modeling, was used to provide a final design which achieved a successful compromise among the various requirements.
Optimum reverberation time for speech intelligibility in classrooms
Authors: Nosal Eva-Marie , Hodgson Murray
Published: February 2014

This work addresses the topical question of the optimum reverberation time (RT) for speech intelligibility in classrooms. Existing literature is reviewed and is found to be inconsistent. Experimental methods generally predict zero optimum RT, while theoretical methods predict nonzero values. These differences are discussed; they appear to stem from different treatments of the background noise. Assuming diffuse-field theory, a theoretical model to predict optimum RT was developed from a previously proposed model [S. R. Bistafa and J. S. Bradley, J. Acoust. Soc. Am. 107, 861–875 (2000)]. It incorporates noise in a physically realistic way and predicts nonzero optimum RTs. Subsequently, to reduce reliance on diffuse-field theory, the model was modified using empirical methods to predict speech level and reverberation times in classrooms [M. R. Hodgson, J. Build. Acoust. (in press, 2001)]. Again, nonzero optimum RTs were predicted. The prediction models and results are presented, practical conclusions are drawn, and suggestions for further work are made.
Speech privacy in open-plan offices. I. Systematic measurements
Authors: Bradley John , Wang Chong
Published: February 2014

This work reports the results of a systematic series of measurements of speech propagation between workstations in a conventional open-plan office. The propagation measurements were repeated as the parameters describing the open-office configuration were systematically changed. The values of the following were varied: workstation panel height, panel absorption, workstation plan size, ceiling height, and ceiling absorption. In addition the effects of the location and type of ceiling light fixtures were investigated as well as details of the workstation furnishings and configuration. The results are evaluated in terms of Speech Intelligibility Index values, SII (ANSI S3.5 1997). The SII is a new version of the articulation index and is a weighted speech-to-noise ratio that is a good measure of the expected speech privacy. The height of the partial height panels separating workstations and the absorption of the ceiling have the most important effects on speech privacy. Workstation size, panel absorption, and lighting configuration have intermediate effects on speech privacy. Ceiling height and workstation configuration had smaller effects on expected speech privacy.
An architectural design tool for the prediction of the acoustic comfort conditions in architectural spaces
Authors: Rodriguez-Manzo Fausto
Published: February 2014

It is usual in many countries that the study programs of architectural studies lack acoustical education; as a consequence, most of their projects and buildings suffer from acoustical problems and noise intrusions, bad acoustical insulation, and spaces reverberant enough to affect speech inteligibility conditions to a large extent. Indeed, this is a problem of acoustical criterion. Due to budgetary reasons and fairly complex calculations for relatively small projects, the architect may not want to be involved in the above, or look for an acoustical consultant. This work presents a simplified model of the acoustical analysis of acoustic comfort conditions in architectural spaces. The model is useful preferably for architectural design purposes, allowing an advanced knowledge of the acoustic comfort conditions of an architectural space. In this model, most of the cases are included, although it is not designed for those spaces in which critical acoustic requirements are called for, such as theaters, and concert halls. The present model is based on the classification of comfort as applied for architecural spaces and human activities. A sample case will be presented to enhance the capabilities of the model.
In vivo quantitation of regional versus systemic SWL-induced free-radical activity
Authors: Auge Brian , Munver Ravi , Kourambas John , Preminger Glenn , Zhong Pei
Published: February 2014

Renal tissue injury in shock wave lithotripsy (SWL) may be attributed directly to vascular trauma and indirectly to ischemia-reperfusion with resultant free-radical formation. We have employed a microdialysis system to assess areas of renal injury in relation to the site of SWL treatment. Swine were assigned to a control group (N=3) and a SWL-treated group (N=3). Microdialysis probes were inserted into the parenchyma of the lower pole, upper pole of right kidney, and the lower pole of left kidney. Seventy-two hours following probe insertion, baseline dialysate samples were collected, after which SWL was administered exclusively to the right kidney lower pole in the treated group, using a Dornier Compact S lithotripter at its highest intensity. Dialysate samples were collected every 1000 shocks. It was found that SWL caused a significant increase in free-radical activity, as measured by lipid peroxidation, in the right lower pole, followed by a moderate increase in the right upper pole. Yet, no free-radical activity was noted in the left kidney. These findings suggest that SWL-induced free-radical activity is localized and confined to the ipsilateral kidney. There does not appear to be systemic circulating nephrotoxic factors following SWL treatment. [Work supported by NIH.]
Cell lysis due to shear in shock wave lithotripsy
Authors: Lokhandwalla Murtuza , Sturtevant Bradford , McAteer James , Williams James
Published: February 2014

Injury to isolated red blood cells (RBCs) and deformation of aluminum foils due to focused shock waves in a cavitation-free environment were investigated. The lithotripter-generated shock wave was refocused by a parabolic reflector. This refocused wave field had a tighter focus (smaller beamwidth and a higher amplitude) than the lithotripter wave field, as characterized by a membrane hydrophone. Cavitation was eliminated by applying overpressure to the fluid. Aluminum foils were used to study shock wave damage and had distinct deformation features corresponding to exposure conditions, i.e., pitting and denting accompanied with wrinkling. Pitting was eliminated by high overpressure (∼12 MPa) and so was due to cavitation bubble collapse, whereas denting and wrinkling were caused by the reflected shock wave refocused by the parabolic reflector. RBCs suspended in phosphate-buffered saline (PBS) were exposed to the reflected wave field from a parabolic reflector and also from a flat reflector. Exposure to the wave field from the parabolic reflector increased hemolysis fourfold compared to untreated controls and was twice that of cell lysis with the flat reflector. Thus, hemolysis was shown to be directly related to the shock-strength gradient and validates shearing as a cell lysis mechanism in SWL. [Work supported by NIH Grant No. P01 DK43881.]
Localized detection of cavitation in vivo
Authors: Bailey Michael R. , Crum Lawrence A. , Miller Nathan , Couret Lisa N. , Sapozhnikov Oleg A. , Pishchalnikov Yuri A. , Keilman George , McAteer James A. , Connors Bret , Evan Andy P.
Published: February 2014

A step in determining cavitation’s deleterious role in shock wave lithotripsy (SWL) is spatially correlating cavitation and tissue damage: Can cavitation be detected in kidney tissue? A system for localized cavitation detection and tests is described. Our lithotripter source and two single-element ring transducers (1.1 MHz, focal length 6.3 cm, radius 1.1–3.5 cm) were aligned confocal and orthogonal. An ultrasound scanhead fit in the central opening. B-mode imaging and fluoroscopy showed the position of the focus within the kidney. Hyperechoic clouds in the image indicated pockets of bubbles during SWL. A coincidence-detection algorithm and the confocal transducers made it possible to localize cavitation to within an 8-mm3 region. Cavitation was detected in a pig kidney during SWL. Following SWL, the tissue region interrogated can be marked with a lesion produced by using the detection transducers as high-intensity focused ultrasound (HIFU) sources. This technique allows one to determine if the site of cavitation detection was located within the kidney tissue. Lesions were produced in pig kidney. Ultimately a ring of lesion might be drawn around the interrogation region so that SWL damage to the region might be assessed and coorelated with cavitation. [Work supported by NIH DK43881 and DK55674.]
Suppression of large intraluminal bubble expansion in SWL
Authors: Zhong Pei , Zhou Yufeng
Published: February 2014

Large, rapid expansion of intraluminal bubbles has recently been demonstrated as a potential mechanism for the rupture of capillaries and small blood vessels in shock wave lithotripsy (SWL). To reduce vascular injury without compromising the fragmentation capability of a lithotripter, we developed a strategy to modify the ellipsoidal reflector of an HM-3 lithotripter so that following each spark discharge a weak compressive pulse is generated to superimpose onto the tensile component of a lithotripter shock wave. This modified waveform was found to significantly suppress bubble expansion; and the propensity of vascular injury, as assessed by the rupture of a cellulose vessel phantom, is reduced by an order of magnitude both at 20 and 24 kV. At 24 kV, stone fragmentation is reduced by about 30% using the modified reflector, which, however, is comparable to that produced by the standard reflector at 20 kV. These results suggest that the modified reflector may be used to produce sufficient stone comminution with much reduced potential for vascular injury in SWL. [Work supported by NIH.]
Time-lapse assessment of SWL shock wave damage to kidney stones using micro-computed tomography (μC
T)
Authors: Cleveland Robin O. , Müller Ralph , Williams James C. , McAteer James A.
Published: February 2014

SWL could be improved with a better understanding of the mechanisms of stone failure. We used μCT to visualize the initiation and progression of fracture in COM stones in vitro and to determine if the stone’s environment influences its mechanism of failure. A desktop μCT (17 μm resolution) was used to collect time-lapse images of the internal and surface structure of kidney stones during administration of SWs using an electrohydraulic lithotripter (20 kV, 1 Hz). Stones were either constrained by water-saturated gauze or were surrounded by water. The constrained stone showed first evidence of fracture on the distal surface at 200 SWs. Subsequent SWs dislodged a slab from the distal side (spall) and separated the stone’s core and shell. In contrast, a stone surrounded by water showed damage at the proximal surface at only 10 SWs. The data imply that the failure mechanism can vary depending on the conditions surrounding a stone. When cavitation was restricted, damage by spall predominated. With sufficient free fluid surrounding the stone, cavitation caused damage at the proximal surface. [Partially supported by NIH through P01-DK 43881 and the M. E. Müller Professorship in Bioengineering at Harvard Medical School.]
Effect of SW rate on stone fragmentation in vivo
Authors: Lingeman James E. , Paterson Ryan F. , Lifshitz David A. , McAteer James A. , Williams James C. , Rietjens Drew L. , Connors Bret A. , Evan Andrew P.
Published: February 2014

The trend toward ungated SWL means that SW’s are often delivered at a fast rate (≥2 Hz). This is a concern, since rapid SW delivery causes increased renal injury in experimental animals. Also, in vitro studies show that slowing the SW rate (<2 Hz) improves stone fragmentation. In the current study, the effect of SW rate on stone comminution was tested in an in vivo model. Gypsum stones were inserted into both kidneys of 100 lb pigs via percutaneous access. SWL was performed (Dornier HM3, 400 SW’s uninterrupted, 20 kV, 2 Hz or 0.5 Hz), and stone fragments were collected and sieved through 2 mm mesh. The percent of stone weight lost (particles <2 mm), was greater in stones shocked at the slower rate, 55.1±4.9% (n=6), compared to the faster rate, 19.4±5.6% (n=6) [p<0.0008]. These data indicate that slowing the SW rate improves the efficiency of stone fragmentation in vivo. It is observed in vitro that bubbles along the SW axis are more numerous with faster SW rate; this could impose a barrier to transmission of SW energy into the stone. Localization of the site of rate-dependent bubble activity could provide clues to help improve SWL. [Work supported by NIH Grant P01 DK43881.]
Vibrational modes and sound spectra of bass steelpans
Authors: Rossing Thomas D. , Hansen Uwe J.
Published: February 2014

The vibrational modes and sound spectra from bass steelpans by two well-known makers are reported. The large note areas generally radiate a strong fundamental along with an octave and a twelfth. The (1,0) mode is most often tuned to the octave, and the (0,1) to the twelfth, but in a few notes these roles are reversed. In some notes, the partial tuned to the twelfth dies out rather slowly, and gives an audible ‘‘aftersound.’’ Modes of vibration in the skirt are made up of bending waves that travel around the circumference. The two circular stiffening ribs appear to have a rather noticeable effect on the vibrational modes of the skirt.
Normal modes of a finite element lip reed model
Authors: Ludwigsen Daniel O. , Strong William J.
Published: February 2014

Models of the lip reed for brass instruments show utility in time-domain simulation with one or two degrees of freedom. Higher-dimensional models may hold further insight into the actual behavior of lip structures in playing conditions. The present model represents a midsagittal slice of lip tissue using ANSYS, a commercial software package for solid modeling and finite element analysis. Modes of the lip model structure provide a first step in understanding its response to pressure loads on the surface in a subsequent time-domain simulation of the player/trombone system. The dependence of the mode frequencies and mode shapes on muscle tissue stiffness can help to inform stiffness parameter selection for simulation, and may offer clues to understanding how the player controls the embouchure.
Symmetries and dynamics of musical scales
Authors: Sevgen Alpar
Published: February 2014

Configurational potential energy, as well as complexity, may be used as a measure for musical scales. To show this, complexities C(n) and energies E(n) of equally tempered scales with the interval structure n={n1,n2,...,nM} for N=12 semitones and M=7 notes are compared. Complexity is the sum of sharps and flats in a scale. Energy E(n) is due to an assumed interaction energy nα between the notes. It is found that the symmetries of C(n) and E(n) are the same: rotations and reflection (i.e., cyclical permutations and reverse ordering, respectively, of the components of n), and note↔no-note transformation (e.g., major↔pentatonic). But beyond that, the complexity and energy models are apparently unrelated. Symmetries explain the groupings of scales but not the differences in complexity or energy of the groups. There is, however, a remarkable agreement between the C(n) and E(n) tables for a range of values of α. (As an example, the harmonic oscillator value α=2 is employed.) That these tables display an almost identical pattern in the ordering of 38 groups comprising 462 scales of 12-tuples implies that energies E(n) can also be used as a measure for musical scales.
An acoustical study on double bass bridge height adjusters
Authors: Brown Andrew W.
Published: February 2014

A study on double bass bridge height adjusters was made using local and international surveys, a listening test survey, and sound spectrum analysis to learn more about the acoustical properties of various bridge adjusters and their current use. A questionnaire sent via e-mail to members of the International Society of Bassists confirmed that preferences and opinions about adjusters vary widely, though some general tendencies are recognizable. Responses also gave some indications why approximately 60 to 80 bassists use bridge adjusters, while adjusters in central Europe are rarely seen. Computerized listening tests showed that all types of bridge height adjusters cause an audible difference in sound compared to a bridge with no adjusters, and that individual models and materials have unique tonal characteristics. Finally, a digital sound analysis was made comparing a bridge with no adjusters to the same bridge fitted successively with six types of bridge height adjusters. The analysis showed that bridge height adjusters make a significant difference in pizzicato decay time depending on the model and material in question, and FFT spectrum analysis of bowed tones showed the sound characteristics of bridge height adjusters throughout the range of the double bass.
Normal modes of vibration in balalaikas
Authors: Morrison Andrew , Rossing Thomas D.
Published: February 2014

Using holographic interferometry, we have studied the vibrational behavior of a prima balalaika, a secondo balalaika, and an alto balalaika, all constructed at the Folk Musical Instrument Manufacturing Company in St. Petersburg, Russia. The modes of lowest frequency are characterized by the in-phase motion of the soundboard, while at higher frequencies we observe modes with longitudinal and transverse nodal lines where the soundboard pivots as it vibrates, much like the guitar. The modal frequencies are compared with the sound spectra recorded when the strings are plucked.
Observer weighting of interaural delays in echo clicks preceded by source clicks that have been attenuated
Authors: Dye Raymond , Gallegos Jose , Brown Christopher
Published: February 2014

This investigation examined the effect that the relative levels of leading and lagging clicks have on binaural precedence. A diotic pulse was presented during the first interval to mark the intracranial midline. In the second interval, two dichotic pulses were presented, separated by an ‘‘echo delay’’ ranging from 1 to 32 ms. The interaural delays of the two pulses were independently selected from a Gaussian distribution. Listeners were instructed to respond according to the laterality of the lagging click. The leading click was attenuated by from 0 to 30 dB. Performance was measured by proportion correct, relative echo weight, and the proportion of responses predicted by the derived weights. At the shortest echo delays, the effect of attenuation on echo weight and proportion correct occurred after merely 6 dB of attenuation. At echo delays longer than 8 ms, the echo weights started out higher but were not as dependent upon source attenuation. The same effect was found for proportion correct. At 4 ms, there were steady increases in both echo weight and proportion correct as the source was attenuated. The proportion of responses accounted for by the weights was dependent upon neither source attenuation nor echo delay. [Work supported by NIDCD.]
The role of masking in the Franssen effect
Authors: Whitmer William M. , Yost William A. , Sheft Stanley
Published: February 2014

The sudden onset of a sound which slowly decays at one loudspeaker can occlude the presence and location of the same sound presented simultaneously with a slow rise time at another loudspeaker. This phenomenon, known as the Franssen effect, has been shown in previous research to be specific to low-frequency pure tones in reverberant rooms. To examine the possible mechanisms involved, listeners heard pure-tone transient/steady-state signal pairs at frequencies ranging from 250–4000 Hz from either one loudspeaker or two contralateral loudspeakers in an eight-speaker array. Signals were masked with Gaussian noise. Using a two-interval, forced-choice tracking procedure, thresholds for detecting the steady-state signals were measured. The transient tone was present in both intervals. The results showed increases across frequencies in threshold of approximately 6 dB for two-source (Franssen) conditions compared to single-source conditions. In an auxiliary experiment, signals were masked with tones of differing frequencies. For Franssen conditions, masking was dependent on the interaction of signal and masker frequencies. Both results are discussed in terms of onset dominance, nonecho suppression and free-field masking. [Work supported by NIDCD.]
Contralateral masking effects in dichotic listening with two competing talkers in the target ear
Authors: Brungart Douglas S. , Simpson Brian D.
Published: February 2014

Some of the most influential experiments in selective auditory attention have been based on a dichotic cocktail party task where listeners are asked to respond to a speech signal presented to one ear while ignoring a simultaneous competing speech signal presented to the other ear. These experiments have generally shown that the intelligibility of a monaural speech signal is unimpeded by the presence of an interfering speech signal at the opposite ear. However, recent results in our laboratory indicate that listeners cannot ignore a speech signal at the unattended ear when two simultaneous speech signals are presented to the target ear. In this study, the intelligibility of a target phrase in a two-talker stimulus presented to one ear was measured monaurally and with a speech or noise signal in the opposite ear. Performance in this task was unaffected when noise was added to the unattended ear, but degraded substantially when speech was added to the unattended ear. These results suggest that there are strong interactions between the monaural processes that listeners use to segregate two spatially colocated voices and the binaural processes they use to segregate voices originating from different apparent locations in space. [Work supported by AFOSR.]
Nonlinear acoustics: Discussions with David Crighton
Authors: Ostrovsky Lev A.
Published: February 2014

This lecture is a brief overview of Professor David Crighton’s important role in nonlinear acoustical research which, as in many other areas, went far beyond his own valuable publications. He was an active organizer of symposia on Nonlinear Acoustics and relevant Euromech meetings. Also personal meetings and discussions with David G. Crighton regarding the topic are memorable for the author.
Hydrofoil sound generation at high Reynolds number
Authors: Judge Carolyn , Bourgoyne Dwayne , Hamel Joshua M. , Ceccio Steven L. , Dowling David R.
Published: February 2014

The unsteady separated turbulent flow near the trailing edge of a loaded hydrofoil is often a source of hydroacoustic noise. Intense turbulence in this region may produce noise directly, but, at low Mach number, hydrodynamically forced structural motions may also radiate sound. In fact, interactions between the foil’s unsteady vortical wake flow and the hydrofoil structure may produce undesired self-excited hydrodynamic-vibratory resonances sometimes called ‘‘singing.’’ This presentation reports experimental results from a series of recent experiments focused on understanding and documenting these phenomena at chord-based Reynolds numbers up to 60 million. The measurements include foil surface static and dynamic pressures, foil vibration, LDV-determined average flow velocities and turbulence quantities, and PIV flow fields in the immediate vicinity of the foil’s trailing edge. The experiments are conducted at the US Navy’s Large Cavitation Channel with a two-dimensional test-section-spanning hydrofoil (2.1 m chord, 3.0 m span) at flow speeds from 0.5–18.3 m/s. Special interest is focused on the trailing edge of the foil where the unsteady Kutta condition is investigated. [Significant assistance provided by personnel from NWSC-CD. Sponsored by Code 333 of ONR.]
Speech analysis in automatic speaker recognition schemes in both forensic and commercial applications
Authors: Ortega-Garcia Javier , Gonzalez-Rodriguez Joaquin
Published: February 2014

Speaker identity is a complex information included in the speech signal and codified in several levels of knowledge. Regarding the phonetic segmental level, this information resides in the specific acoustic resonances of the vocal tract that can be observed in the spectral envelope. Considering the nonstationarity of speech signals, short-time speech analysis techniques are employed through time-windowing procedures. Homomorfic cepstral analysis is then usually performed, as deconvolution between glottal information and vocal tract information is efficiently accomplished in this domain, guiding to a parametrization process of each frame through different techniques, as Mel-frequency-derived (MFCC) or linear prediction-based (LPCC) cepstral analysis. After the parametrization stage, probabilistic characterization of speakers identity is attained, usually through the use of left-to-right or ergodic hidden Markov models (HMM). Two different operating modes are clearly found in speaker recognition, namely (i) speaker identification, task in which a speaker has to be selected from a given set of speakers models, and (ii) speaker verification, in which a binary decision (accepted/rejected) has to be taken regarding the input unknown speech. Automatic speaker recognition leads to development of both commercial and forensic applications, but the cost of the decision of the system clearly separates the technical specificity of them.
A robust fundamental frequency detection algorithm based on the spectrogram
Authors: Diaz Jose , Sapienza Christine , Rothman Howard , Natour Yaser
Published: February 2014

The detection of fundamental frequency (Fo) in speech has often been shown to be a particularly difficult signal processing problem. This parameter is a necessary one for documenting vocal fold vibration and alterations to these vibratory patterns in the presence of pathology. There exist a variety of algorithms for extracting and analyzing Fo. It has been reported that these techniques do not work well for different types of talkers and decrease in performance as the noise level increases. The main objective of this research was to develop a robust algorithm for the extraction and analysis of Fo from normal and pathological voices. This algorithm is based on the spectrogram and makes use of artificial intelligence techniques to extract Fo. An algorithm was developed and tested with six normal and six abnormal samples, which contain a sustained vowel. These 12 samples were also analyzed by two commercial software packages, which make use of other techniques, and the results were compared to the results provided by the proposed algorithm. The results provided by the proposed algorithm agreed with those of the other two software packages, and the algorithm was able to detect Fo for a longer period of time.
Dynamic synapse neural network (DSNN): A new configuration based on wavelet filter bank and genetic algorithm
Authors: Heidari Namarvar Hassan , Liaw Jim-Shih , Berger Theodore W.
Published: February 2014

A new DSNN architecture has been developed by the wavelet filter bank and the genetic algorithm (GA) training algorithm. The original DSNN [J.-S. Liaw and T. W. Berger, Hippocampus 6, 591–600 (1996)] was based on the integrate-and-fire-based neurons using Hebbian learning. Implementing input neurons of DSNN as wavelet filters has been shown to increase the retention of input information and the system performance in comparison to the integrate-and-fire neural network with a Hebbian learning algorithm. This study has shown improvements in achieving convergence of the neural network for difficult discrimination conditions. The Hebbian and anti-Hebbian learning rules do not take into account all of the system parameters which may have a significant impact on system performance. Hence we used the GA as the training algorithm to provide an efficient way for searching parameter spaces. This novel network has been tested by raw speech waveforms for a speech recognition task. The system performance during training phase was highly improved in comparison with the prior version of DSNN. [Work supported by DARPA.]
Automatic classification of the telephone-listening environment in a hearing aid
Authors: Nordqvist Peter , Dai Huanping
Published: February 2014

An algorithm is developed for automatic classification of the telephone-listening environment in a hearing instrument. The system would enable the hearing aid to automatically change its behavior when it is used for a telephone conversation (e.g., decrease the amplification in the hearing aid, or adapt the feedback suppression algorithm for reflections from the telephone handset). The telephone-listening environment and a reference listening environment are modeled with discrete hidden Markov models. The reference listening environment contains information about clean speech and a few different types of background noises. The probabilities for the different listening environments are calculated with forward algorithm for each frame of the input sound, and are compared with each other in order to detect the telephone-listening environment. Preliminary results demonstrate accurate classification of telephone speech by the hidden Markov system. [Work supported by GN ReSound.]
A new technique for joint optimization of excitation and model parameters in parametric speech coders
Authors: Lashkari Khosrow , Miki Toshio
Published: February 2014

In a speech coding system, synthesis error (the difference between the original speech at the encoder input and the reproduced speech at the decoder output) is a more relevant measure of signal distortion than linear prediction (LP) error. By minimizing the synthesis error instead of the linear prediction error, the analysis and synthesis stages become more compatible. While LP error is linear in filter parameters, synthesis error is a highly nonlinear function of these parameters, making it computationally intractable for real-time applications. This paper presents a computationally feasible solution for minimizing the synthesis error applicable for joint optimization of the excitation and model parameters in real time. Using a gradient search in the root domain, synthesis error is minimized by re-optimizing the filter parameters for a given excitation. Starting the gradient search from the LPC solution, the resultant synthesis error produced by the proposed technique is guaranteed to be lower than the synthesis error using the LPC filter. By adding an extra minimization step, this technique can be incorporated into any parametric speech coder including LPC, multipulse LPC and CELP speech coders. The new technique and results of application to real speech will be presented.