USVSEG: A robust method for segmentation of ultrasonic vocalizations in rodents.

Rodents' ultrasonic vocalizations (USVs) provide useful information for assessing their social behaviors. Despite previous efforts in classifying subcategories of time-frequency patterns of USV syllables to study their functional relevance, methods for detecting vocal elements from continuously recorded data have remained sub-optimal. Here, we propose a novel procedure for detecting USV segments in continuous sound data containing background noise recorded during the observation of social behavior. The proposed procedure utilizes a stable version of the sound spectrogram and additional signal processing for better separation of vocal signals by reducing the variation of the background noise. Our procedure also provides precise time tracking of spectral peaks within each syllable. We demonstrated that this procedure can be applied to a variety of USVs obtained from several rodent species. Performance tests showed this method had greater accuracy in detecting USV syllables than conventional detection methods.

Reproducibility of Dual-Microphone Voice Range Profile Equipment.

Purpose: The aim of this study was to add further knowledge about the usefulness of the Voice Range Profile (VRP) assessment in clinical settings and research by analyzing VRP dual-microphone equipment precision, reliability, and room effect. Method: Test-retest studies were conducted in an anechoic chamber and an office: (a) comparing sound pressure levels (SPLs) from a dual-microphone VRP device, the Voice Profiler, when given the same input repeatedly (test-retest reliability); (b) comparing SPLs from 3 devices when given the same input repeatedly (intervariation); and (c) assessing the room effect. Results: (a) The mean standard deviation across 17 measurement points was 0.7 dB for 1 device. (b) One device was less precise than the other 2 devices. All devices presented high SPLs at low frequencies compared with the reference. (c) Mean SPLs were almost equal in the anechoic chamber and the office. Conclusions: The high test-retest reliability of the dual-microphone VRP equipment, especially in general office surroundings, is a positive finding. Attention must be paid to specific factors such as using the same device when comparing the same voice before and after treatment, caution in headset placement, and manual recalibrations when automatic recalibration occurs. We suggest recalibrations verified with a reference source at regular intervals.

Assessment of continuous acoustic respiratory rate monitoring as an addition to a pulse oximetry-based patient surveillance system.

Technology advances make it possible to consider continuous acoustic respiratory rate monitoring as an integral component of physiologic surveillance systems. This study explores technical and logistical aspects of augmenting pulse oximetry-based patient surveillance systems with continuous respiratory rate monitoring and offers some insight into the impact on patient deterioration detection that may result. Acoustic respiratory rate sensors were introduced to a general care pulse oximetry-based surveillance system with respiratory rate alarms deactivated. Simulation was used after 4324 patient days to determine appropriate alarm thresholds for respiratory rate, which were then activated. Data were collected for an additional 4382 patient days. Physiologic parameters, alarm data, sensor utilization and patient/staff feedback were collected throughout the study and analyzed. No notable technical or workflow issues were observed. Sensor utilization was 57 %, with patient refusal leading reasons for nonuse (22.7 %). With respiratory rate alarm thresholds set to 6 and 40 breaths/min., the majority of nurse pager clinical notifications were triggered by low oxygen saturation values (43 %), followed by low respiratory rate values (21 %) and low pulse rate values (13 %). Mean respiratory rate collected was 16.6 ± 3.8 breaths/min. The vast majority (82 %) of low oxygen saturation states coincided with normal respiration rates of 12-20 breaths/min. Continuous respiratory rate monitoring can be successfully added to a pulse oximetry-based surveillance system without significant technical, logistical or workflow issues and is moderately well-tolerated by patients. Respiratory rate sensor alarms did not significantly impact overall system alarm burden. Respiratory rate and oxygen saturation distributions suggest adding continuous respiratory rate monitoring to a pulse oximetry-based surveillance system may not significantly improve patient deterioration detection.

Nocturnal "humming" vocalizations: adding a piece to the puzzle of giraffe vocal communication.

BACKGROUND: Recent research reveals that giraffes (Giraffa camelopardalis sp.) exhibit a socially structured, fission-fusion system. In other species possessing this kind of society, information exchange is important and vocal communication is usually well developed. But is this true for giraffes? Giraffes are known to produce sounds, but there is no evidence that they use vocalizations for communication. Reports on giraffe vocalizations are mainly anecdotal and the missing acoustic descriptions make it difficult to establish a call nomenclature. Despite inconclusive evidence to date, it is widely assumed that giraffes produce infrasonic vocalizations similar to elephants. In order to initiate a more detailed investigation of the vocal communication in giraffes, we collected data of captive individuals during day and night. We particularly focussed on detecting tonal, infrasonic or sustained vocalizations. FINDINGS: We collected over 947 h of audio material in three European zoos and quantified the spectral and temporal components of acoustic signals to obtain an accurate set of acoustic parameters. Besides the known burst, snorts and grunts, we detected harmonic, sustained and frequency-modulated "humming" vocalizations during night recordings. None of the recorded vocalizations were within the infrasonic range. CONCLUSIONS: These results show that giraffes do produce vocalizations, which, based on their acoustic structure, might have the potential to function as communicative signals to convey information about the physical and motivational attributes of the caller. The data further reveal that the assumption of infrasonic communication in giraffes needs to be considered with caution and requires further investigations in future studies.

Noise Levels in Patient Rooms and at Nursing Stations at Three VA Medical Centers.

OBJECTIVES: To conduct an assessment of sound, dB(A) levels, in two areas of the hospital: patient rooms and nurse stations using sound meters (SMs). BACKGROUND: The World Health Organization (WHO) recommends sound levels of 35 dB(A) during the day and 30 dB(A) during the night; however, many hospitals exceed these recommended levels. Assessing post-occupancy sound levels enables hospital administrators and healthcare workers to identify whether interventions to improve sound levels are needed. METHODS: Sound assessments were conducted at three healthcare facilities in both patient rooms and nursing stations, and we include information on facility characteristics. An Amprobe SM-20A Sound Level Meter was placed for a 24-hr period and recorded decibel levels every 8 min. These sound levels were averaged for each hour for reporting purposes. Averages as well as highest and lowest readings are reported for both daytime (8 a.m.-10 p.m.) and nighttime (10 p.m.-8 a.m.) for each facility. RESULTS: All three sites are considered urban and are classified with the highest complexity level (1a). Average daytime measurements for patient rooms and their corresponding nurses stations were as follows: Site A-63 dB(A)/56 dB(A), Site B-52 dB(A)/55 dB(A), and Site C-42 dB(A)/59 dB(A). Average nighttime measurements for patient rooms and nurses stations were Site A-62 dB(A)/55 dB(A), Site B-48 dB(A)/55 dB(A), and Site C-42 dB(A)/60 dB(A). CONCLUSION: Our findings, considered independently and collectively, showed that facilities in this study exceeded the WHO-recommended sound levels for patient rooms of 35 dB(A) during daytime and 30 dB(A) during nighttime. Research has reported negative patient outcomes, for example, decreased satisfaction, sleep disturbance, and higher incidence of rehospitalization in patients staying in areas with higher noise levels.

Automated acoustic analysis in detection of spontaneous swallows in Parkinson's disease.

Acoustic monitoring of swallow frequency has become important as the frequency of spontaneous swallowing can be an index for dysphagia and related complications. In addition, it can be employed as an objective quantification of ingestive behavior. Commonly, swallowing complications are manually detected using videofluoroscopy recordings, which require expensive equipment and exposure to radiation. In this study, a noninvasive automated technique is proposed that uses breath and swallowing recordings obtained via a microphone located over the laryngopharynx. Nonlinear diffusion filters were used in which a scale-space decomposition of recorded sound at different levels extract swallows from breath sounds and artifacts. This technique was compared to manual detection of swallows using acoustic signals on a sample of 34 subjects with Parkinson's disease. A speech language pathologist identified five subjects who showed aspiration during the videofluoroscopic swallowing study. The proposed automated method identified swallows with a sensitivity of 86.67 %, a specificity of 77.50 %, and an accuracy of 82.35 %. These results indicate the validity of automated acoustic recognition of swallowing as a fast and efficient approach to objectively estimate spontaneous swallow frequency.

Differentiating between underwater construction noise of monopile and jacket foundations for offshore windmills: a case study from the Belgian part of the North Sea.

Steel monopiles, jackets requiring four steel pinpiles, and gravity-based foundations were applied in offshore wind farms in the Belgian part of the North Sea. This paper compares the underwater noise generated during the piling activities of steel monopiles at the Belwind wind farm (Blighbank) with that of jacket pinpiles at the C-Power project (Thorntonbank). Underwater noise was measured at various distances from the pile driving location. The underwater noise was quantified by its zero to peak sound pressure level (L(z-p)), unweighted sound exposure level (SEL), cumulative SEL, and 1/3 octave spectra. No significant differences in L(z-p) could be demonstrated (monopile L(z-p): 179-194 dB re 1 µPa, jacket L(z-p): 172-189 dB re 1 µPa). SEL showed no statistical difference between monopile and jacket and varied between 145 and 168 dB re 1 µPa(2)s. Furthermore, near identical spectra were measured for both types of piling. Piling of the jacket pinpiles took, however, about 2.5 times the time of the monopile. When standardised to megawatt installed per foundation both types of piling scored near equally. As an illustration, the radius of major behavioural disturbance (L(p-p) = 155 dB re 1 µPa) in the harbour porpoise Phocoena phocoena was estimated by a model at 16 km for monopiles and at 8 km for jacket.

[Objective assessment of total noise exposure over 24 hours: a cross-sectional study in Bavaria]. / Objektive Bestimmung der 24-Stunden-Gesamtlärmbelastung: eine Querschnittsstudie in Bayern.

INTRODUCTION: Noise can affect well-being and performance of individuals and might be associated with an increased risk of cardiovascular events. To date most epidemiological studies considered exposure from a single source of noise. The EU Environmental Noise Directive (2002/49/EC) requires a summative measurement of ambient noise. This study aimed to capture the participants' exposure to environmental noise by means of personal noise dosimetry. METHODS: Children (n=628, participation=61%, age 8-12 years), adolescents (n=632, participation=58%, age 13-17 years) and adults (n=482, participation=40%, age 18-65 years) were selected randomly from the population registry of 4 Bavarian towns and were invited to participate in a 24-h measurement using noise dosimetry. Noise exposures during day and night were analyzed separately. In addition, predictors of noise exposure were assessed. RESULTS: For daytime noise exposure mean±standard deviation were in children 80.0±5.8 dB(A), in adolescents 76.0±6.2 dB(A), in adults 72.1±6.1 dB(A) (p(ANOVA)<0.001). During the day personal noise exposure was statistically significantly higher for participants from smaller towns than for those living in Munich, while nighttime noise exposure was highest for participants from Munich [44.1±7.2 dB(A)]. CONCLUSION: The summative noise exposure in urban Bavaria is high, in particular among children at daytime. Increased exposure levels in children might be caused by themselves while, e.g., playing. Whether the higher daytime exposure in towns is due to high noise levels commuting between home and work has to be assessed in future studies.

Use of spectral/cepstral analyses for differentiating normal from hypofunctional voices in sustained vowel and continuous speech contexts.

PURPOSE: In this study, the authors evaluated the diagnostic value of spectral/cepstral measures to differentiate dysphonic from nondysphonic voices using sustained vowels and continuous speech samples. METHODOLOGY: Thirty-two age- and gender-matched individuals (16 participants with dysphonia and 16 controls) were recorded reading a standard passage (The Rainbow Passage; Fairbanks, 1960) and sustaining the vowel /α/. Recorded voices were analyzed with custom software that calculated 4 spectral/cepstral measures. RESULTS: Measures of cepstral peak prominence (CPP) and low-high spectral ratio (L/H ratio) were significantly different between groups in both speaking conditions; the standard deviation of the CPP was significantly different between groups in continuous speech only. In differentiating dysphonic individuals with a hypofunctional etiology from nondysphonic individuals, receiver operating characteristic (ROC) analyses demonstrated (a) high sensitivity and high specificity for the CPP in the sustained vowel condition and (b) high sensitivity and moderate specificity for the CPP in the speech condition. CONCLUSIONS: In a sample of dysphonic speakers (hypofunctional etiologies) versus typical speakers, spectral/cepstral measures of CPP and L/H ratio were able to differentiate these groups from one another in both vowel prolongation and continuous speech contexts with high sensitivity and specificity. The results of this study support the growing body of literature documenting the significant value of cepstral and other spectral-based acoustic measures to the clinical evaluation and management processes.

Multiband analysis and synthesis of spectro-temporal modulations of Fourier spectrogram.

The two-dimensional spectro-temporal modulation filtering concept of the auditory model [T. Chi, P. Ru, and S. A. Shamma, J. Acoust. Soc. Am. 118(2), 887-906 (2005)] is implemented on the Fourier spectrogram. The Fourier magnitude spectrogram is analyzed in terms of its joint spectro-temporal modulations, which embed the temporal dynamics and spectral structures. Instead of iterative projection methods, the overlap-and-add method is adopted to invert modified Fourier spectrograms back to sounds. The proposed framework not only provides a similar spectro-temporal analytical process for sounds as the auditory model but also produces synthesized sounds with better quality in a timely manner, which makes proposed framework feasible to human speech recognition (HSR) applications as well.

Sonography and sociality: obstetrical ultrasound imaging in urban Vietnam.

This article is about new reproductive technologies, maternal anxieties, and existential uncertainties. It explores the question of why pregnant women in Vietnam's capital, Hanoi, have become avid consumers of obstetrical ultrasound scanning even while expressing profound doubts regarding the reliability and safety of this new technology of pregnancy. Through a phenomenological analysis of the social production of women's sense of reproductive risks and uncertainties, the article shows how Hanoian women's paradoxical stances toward ultrasound imaging can be explained through a consideration of embodied and historically generated experiences within everyday local worlds. The article argues that the "scientific stories" of fetal well-being and normality that are produced through ultrasonography are challenged by vivid and continual exchanges in everyday lives of stories of the inherent uncertainties of existence in general and of human reproduction in particular.

Loudness pattern-based speech quality evaluation using bayesian modeling and Markov chain Monte Carlo methods.

This work presents a speech quality evaluation method which is based on Moore and Glasberg's loudness model and Bayesian modeling. In the proposed method, the differences between the loudness patterns of the original and processed speech signals are employed as the observed features for representing speech quality, a Bayesian learning model is exploited as the cognitive model which maps the features into quality scores, and Markov chain Monte Carlo methods are used for the Bayesian computation. The performance of the proposed method was demonstrated through comparisons with the state-of-the-art speech quality evaluation standard, ITU-T P.862, using seven ITU subjective quality databases.

Discrimination of starting phase with sinusoidal envelope modulation.

Modulation-filterbank models discard phase information above very low rates of amplitude modulation (AM). The present work evaluated this restriction by measuring thresholds for discriminating the starting phase of sinusoidal modulators of wideband-noise carriers. Results showed a low-pass characteristic with some listeners unable to perform the task once the modulation rate was greater than 12.5 Hz. For others, however, thresholds were obtained with AM rates of up to one to two octaves higher. Intersubject variability may in part relate to the presence of multiple discrimination cues, with only some based on comparison of the ongoing pattern of envelope fluctuation.

Evolution of breast cancer screening in countries with intermediate and increasing incidence of breast cancer.

BACKGROUND: Few studies have been published regarding the practice of breast cancer screening in Asian countries. AIMS: The present study illustrates how the health policy for breast cancer screening has evolved in Taiwan from selective mammographic screening within a high-risk group, firstly to a programme of physical examination by public health nurses, and finally to a two-stage breast cancer screening programme, with a risk assessment followed by mammography for those at moderate to high risk. DATA SOURCES: Breast cancer screening has evolved from 1995 to 2004 in Taiwan in three stages: (1) selective screening for breast cancer with mammography, ultrasound and physical examination only in first-degree relatives of breast cancer cases (1995-1998); (2) a programme of mass screening (1999-2001) with physical examination by public health nurses; and (3) two-stage breast cancer screening with a risk factor questionnaire and mammography for those deemed at moderate-to-high risk (2002-2004). The questionnaire was based on significant risk factors in a previous epidemiological study, in conjunction with the physical examination programme, a risk score was constructed from the logistic regression coefficients from the previous study, and women with a score above the median in the previous epidemiological study were assigned to mammography. RESULTS: Two-stage mammography screening had the most favourable results compared with the two previous screening regimes. It had a positive predictive value of recall after mammography of 14%, compared with 8% for selective screening and 2% for physical examination. Of screen-detected cancers in the two-stage programme, 71% were either ductal carcinoma in situ or stage T1, compared with 61% for selective screening and 60% for physical examination. The area under the receiver operating characteristic curve was 71% for the two-stage programme. CONCLUSIONS: For a low- to medium-risk country such as Taiwan, two-stage screening has acceptable parameters of recall and cancer detection, and compares well with other screening strategies.

Automated auditory response detection: statistical problems with repeated testing.

Sequential application of a statistical test is usually applied in an automated auditory response detection algorithm. The sequential test strategy is very time-efficient but increases the probability of a false rejection of the null-hypothesis. For this reason, it is necessary to correct the critical test value. However, the well-known Bonferroni correction leads to an over-correction when dealing with dependent or partly dependent data. The objective of the study reported here was to develop a method to determine the critical test value for the sequential testing of dependent data. Extensive Monte Carlo simulations were used to develop this method. The simulation results were reviewed and the benefit of the suggested method, in comparison to the Bonferroni correction, was shown using a large sample of real amplitude modulation following response data. The detection rate determined for these data and the ROC curve demonstrate the advantage of using the method suggested here.

A statistics-based pitch contour model for Mandarin speech.

A statistics-based syllable pitch contour model for Mandarin speech is proposed. This approach takes the mean and the shape of a syllable log-pitch contour as two basic modeling units and considers several affecting factors that contribute to their variations. The affecting factors include the speaker, prosodic state (which essentially represents the high-level linguistic components of F0 and will be explained more clearly in Sec. I), tone, and initial and final syllable classes. The parameters of the two modeling units were automatically estimated using the expectation-maximization (EM) algorithm. Experimental results showed that the root mean squared errors (RMSEs) obtained in the closed and open tests in the reconstructed pitch period were 0.362 and 0.373 ms, respectively. This model provides a way to separate the effects of several major factors. All of the inferred values of the affecting factors were in close agreement with our prior linguistic knowledge. It also gives a quantitative and more complete description of the coarticulation effect of neighboring tones rather than conventional qualitative descriptions of the tone sandhi rules. In addition, the model can provide useful cues to determine the prosodic phrase boundaries, including those occurring at intersyllable locations, with or without punctuation marks.

Automatic classification and speaker identification of African elephant (Loxodonta africana) vocalizations.

A hidden Markov model (HMM) system is presented for automatically classifying African elephant vocalizations. The development of the system is motivated by successful models from human speech analysis and recognition. Classification features include frequency-shifted Mel-frequency cepstral coefficients (MFCCs) and log energy, spectrally motivated features which are commonly used in human speech processing. Experiments, including vocalization type classification and speaker identification, are performed on vocalizations collected from captive elephants in a naturalistic environment. The system classified vocalizations with accuracies of 94.3% and 82.5% for type classification and speaker identification classification experiments, respectively. Classification accuracy, statistical significance tests on the model parameters, and qualitative analysis support the effectiveness and robustness of this approach for vocalization analysis in nonhuman species.

Robustness of spatial average equalization: a statistical reverberation model approach.

Traditionally, multiple listener room equalization is performed to improve sound quality at all listeners, during audio playback, in a multiple listener environment (e.g., movie theaters, automobiles, etc.). A typical way of doing multiple listener equalization is through spatial averaging, where the room responses are averaged spatially between positions and an inverse equalization filter is found from the spatially averaged result. However, the equalization performance, will be affected if there is a mismatch between the position of the microphones (which are used for measuring the room responses for designing the equalization filter) and the actual center of listener head position (during playback). In this paper, we will present results on the effects of microphone-listener mismatch on spatial average equalization performance. The results indicate that, for the analyzed rectangular configuration, the region of effective equalization depends on (i) the distance of a listener from the source, (ii) the amount of mismatch between the responses, and (iii) the frequency of the audio signal. We also present some convergence analysis to interpret the results.

The statistical structure of human speech sounds predicts musical universals.

The similarity of musical scales and consonance judgments across human populations has no generally accepted explanation. Here we present evidence that these aspects of auditory perception arise from the statistical structure of naturally occurring periodic sound stimuli. An analysis of speech sounds, the principal source of periodic sound stimuli in the human acoustical environment, shows that the probability distribution of amplitude-frequency combinations in human utterances predicts both the structure of the chromatic scale and consonance ordering. These observations suggest that what we hear is determined by the statistical relationship between acoustical stimuli and their naturally occurring sources, rather than by the physical parameters of the stimulus per se.