bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of periodic wind turbine noise on infrasound array measurements
Authors: Pilger Christoph , Ceranna Lars
Published: November 2016

Aerodynamic noise from the continuously growing number of wind turbines in Germany creates increasing problems for infrasound array measurements recording acoustic signals at frequencies below 20 Hz. Ten years of continuous data (2006-2015) from the 4-element infrasound array IGADE in Northern Germany are analysed to quantify the influence of wind turbine noise in terms of enhanced amplitude modulations. Furthermore, a theoretical model is derived and validated by a field experiment with mobile micro-barometers. Fieldwork was carried out to measure the infrasonic pressure level of a single horizontal-axis 200 kW wind turbine and to extrapolate the noise effect for turbines with higher electric powers and for a larger number of collocated wind turbines. The model estimates the generated sound pressure level of wind turbines and thus enables for specifying the minimum allowable distance between wind turbines and infrasound stations for undisturbed recording. This aspect is particularly important to guarantee the monitoring performance of the German infrasound stations I26DE in the Bavarian Forest and I27DE in Antarctica. These stations are part of the International Monitoring System (IMS) verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and thus have to meet stringent specifications with respect to infrasonic background noise.
A numerical study of inflow turbulence distortion in the vicinity of blade leading edges
Authors: Hainaut Thomas , Gabard Gwenael , Clair Vincent
Published: November 2016

The interaction of the rotor with inflow turbulence is a source of broadband noise, dominant at high wind speeds. In the vicinity of the leading edge of realistic blades, the mean flow distorts the turbulence, resulting in an attenuation of the high-frequency part of the radiated noise compared to zero-thickness blades. In this paper, to study this turbulence distortion by the mean flow, two different numerical approaches are considered. First, the linearized Euler equations are solved in the time-domain using a finite difference code to model the response of an isolated blade interacting with synthetic turbulence. Second, a vorticity approach is applied, using the Biot-Savart law combined with a vortex panel method. Using these approaches on multiple configurations, the up-wash velocity fluctuations along a streamline which goes to the stagnation point, show a decrease of the turbulent levels, from a threshold distance independent of the wavenumber. This decay is then inverted for low frequencies after a wavenumber dependent threshold distance. The turbulence characteristics are found to have no effect on the distortion, whereas the geometry forward the position of the maximum thickness has an effect on this distortion. The full paper will contain more physical insights responsible for this distortion.
Acoustic characterization of in-room footfall noise
Authors: Rawlings Samantha B. , Magee Joshua A. , Tanen Robert M. , Silver Jonathan C. , Celmer Robert D.
Published: November 2016

Existing literature concerning footfalls is primarily focused on its transmission between spaces, such as a floor/ceiling's Impact Isolation Class. Studies at the University of Hartford measured in-room sound power spectra produced by footfalls on twelve different floor surfaces using human subjects and a standard tapping machine. Within a qualified reverberation room, fourteen male and female subjects walked on the floor surfaces while wearing three different types of footwear: leather-soled shoes (hard), rubber-soled shoes (medium), and sneakers (soft). Sound power spectra and vibratory signatures were measured in 1/3 octaves according to the ISO 3741 standard. A tapping machine was also used on each floor profile using both standard drop weights and with cored samples of the same shoe soles attached to the bottom of each weight. The data for each floor profile produced averages by shoe type along with corresponding 95% confidence intervals. Correlations between sound power and vibratory spectra produced with human walkers versus tapping machine (both with and without “shoes”) were investigated, resulting in correction factors to model machine tapping as human footfalls. [Work supported by The Paul S. Veneklasen Research Foundation.]
American Society of Testing Materials draft standard for rating in-room floor impact noise
Authors: Lilly Jerry G.
Published: November 2016

In 2010 an ASTM subcommittee was formed to assess the possibility of rating the noisiness of different floor surfaces from impacts such as footfalls and dropped objects. Since that time the subcommittee has been meeting biannually to discuss potential impact noise sources and measurement techniques that could be used in a future standard. Different impact sources were evaluated including footfalls with different shoe types, golf balls, and the standard mechanical tapping machine. Both field and laboratory measurements were considered. This paper presents some of the preliminary test results that were obtained and the current status of the proposed laboratory standard.
Characterization of a local scatterer in a plate from reverberation of flexural waves
Authors: Moulin Emmanuel , Achdjian Hossep , Benmeddour Farouk , Chehami Lynda , Assaad Jamal , Dupont Lucie
Published: November 2016

In media where acoustic waves are subject to multiple propagation paths (scattering or reverberation), recorded acoustic signals present a random aspect. Still, such signals carry some information about the medium, and ensemble averaging can give access to the estimation of a number of useful parameters. A well-known example, in room acoustics, is the estimation of absorption coefficients of walls from average decrease of the reverberation envelopes. In the work reported here, we have proposed a statistical model allowing to relate the scattering properties of a local heterogeneity (defect) to the average properties of reverberated acoustic signals in a solid plate. A theoretical expression of the averaged envelope of signals produced by scattered and reverberated flexural waves has been derived and both numerically and experimentally validated. A simple curve-fitting procedure applied to signals recorded on a few receivers then allows an experimental estimation of the scattering cross-section of the heterogeneity.
Integrity evaluation of adhesive anchors using electromagnetic acoustic transducer
Authors: Hasebe Kazuhiko , Mizuno Yosuke , Nakamura Kentaro
Published: November 2016

The aging of social infrastructures has recently become a serious problem. The high efficiency of the testing is required to handle increased inspection demand. There is interest in testing the soundness of adhesive anchors. Bolts are connected to a concrete using holes filled with adhesive materials. Since anchor bolts is inspected by skilled workers manually, it is difficult to improve the efficiency. Several sensing methods have been proposed, but these measurements require a precision alignment or contact. We propose a non-contact evaluation method of adhesive anchors using an electromagnetic acoustic transducer (EMAT). An EMAT is a transducer for non-contact vibration generation and reception based on electromagnetic mechanisms. A neodymium ring magnet and two coils were used as an EMAT. We used 100 mm long M8 and M12 steel bolts mounted with epoxy resin in 70 mm depth holes in concrete. The EMAT which was placed around the bolt excited longitudinal vibrations of bolt by burst waves. Vibration signals were received after the excitation. The relationships between the resin amount and the resonance characteristics of the vibrations are evaluated for pursuing the applicability of this method to the on-site inspection. Resonance frequencies and quality factors are utilized for health monitoring of adhesive anchors.
Liquid loading characteristics of multiple SH-wave roundtrip in c-axis parallel oriented ZnO film/silica glass pipe
Authors: Takayanagi Shinji , Hiyama Shoko , Matsukawa Mami , Yanagitani Takahiko
Published: November 2016

Shear waves with in-plane displacement are suitable for liquid sensors because they can propagate without the energy leakage into liquid. In previous study, we have demonstrated the SH-SAW excitation with (11-20) oriented ZnO film whose c-axis is parallel to the substrate plane [1]. For a high sensitive sensor, the long propagation path is needed to detect small changes of the velocity and amplitude. Multiple wave roundtrips on a pipe surface realizes the long propagation path. In this study, we fabricated IDT/c-axis parallel oriented ZnO film/silica glass pipe structure. The fourth roundtrip was observed by the time response measurement using a network analyzer. The insertion loss of the first lap consisted of two frequency components at 131 MHz and 160-350 MHz. We also measured the liquid loading characteristics by immersing the inside pipe surface. Compared with the unloaded characteristics, insertion losses with pure water increased 0.6 dB at 131 MHz and 1.1 dB at 236 MHz. Because of small increases in the insertion losses, we can conclude that SH-type plate wave was excited. Viscosity measurements with the inside pipe surface are expected. [1] A. Tanaka, et al., IEEE TUFFC, 55, 2709 (2008).
Injection of liquid into ultrasonic standing wave fields by exciting flexural vibrations on needle
Authors: Tadakoshi Haruna , Tanaka Hiroki , Mizuno Yosuke , Nakamura Kentaro
Published: November 2016

There is a large need to handle droplets without contact in the development of new drug and materials. We have been trying to utilize ultrasonic levitation for this aim. It is needed to inject a droplet of precise volume into required location of the levitation device. But it is difficult to control the droplet volume using a syringe due to the influence of surface tension. In this study, by exciting ultrasonic vibrations on a needle, we investigated the control method of droplet volume and ejection timing. Exciting flexural vibrations on a needle for 0.2 seconds, a water droplet of 18-28 mg was dropped with a good controllability and the timing of inject can be regulated. To elucidate this dropping mechanism, we observed the behavior of the droplet. Capillary waves were excited on the droplet, and the force of 0.7 times of gravity exerted by vibration was applied on the droplet according to our estimation. Next, we examined the effect of droplet volume on the resonance frequency of flexural vibrations of the needle, and we confirmed that there was a little influence between them. This means that there is no need to change the frequency in accordance with the volume of droplets.
Amplitude modulation masking for frequency modulation detection
Authors: King Andrew J. , Lorenzi Christian
Published: November 2016

It is generally assumed that frequency modulation (FM) is detected as amplitude modulation (AM) for fast FM rates with low carrier frequencies, and for all FM rates with high carrier frequencies. If this is the case, then FM detection in the presence of an AM masker should exhibit the main features of AM masking: tuning, dependency on AM masker depth, negative masking, beating effects and phase effects. We explored the masking effects produced by sinusoidal AM on detection thresholds of sinusoidal FM for normal-hearing listeners. FM rates ranged between 2 and 64 Hz. The carrier was either a 500-Hz or a 5000-Hz pure tone that was either unmodulated in amplitude or modulated in amplitude at 2 or 16 Hz. The masker AM depth was fixed to either 50% or 25%, and stimulus duration was set to either 500 ms or 1 sec. Additionally, detection thresholds were tested as a function of the phase relationship between a 2-Hz FM target and a 2- or 4-Hz AM masker, and between a 16-Hz FM target and an 8-, 16-, or 32-Hz AM masker. The data will be discussed in light of previous studies on AM masking and the modulation filter-bank concept.
Comparing identification of vocal imitations and computational sketches of everyday sounds
Authors: Lemaitre Guillaume , Houix Olivier , Voisin Frédéric , Misdariis Nicolas , Susini Patrick
Published: November 2016

Sounds are notably difficult to describe. It is thus not surprising that human speakers often use many imitative vocalizations to communicate about sounds. In practice, vocal imitations of non-speech everyday sounds (e.g., the sound of a car passing by) are very effective: listeners identify sounds better with vocal imitations than with verbal descriptions, despite the fact that vocal imitations are often inaccurate, constrained by the human vocal apparatus. The present study investigated the semantic representations evoked by vocal imitations by experimentally quantifying how well listeners could match sounds to category labels. It compared two different types of sounds: human vocal imitations, and computational auditory sketches (created by algorithmic computations), both based on easily identifiable sounds (sounds of human actions and manufactured products). The results show that performance with the best vocal imitations was similar to the best auditory sketches for most categories of sounds. More detailed analyses showed that the acoustic distance between vocal imitations and referent sounds is not sufficient to account for such performance. They suggested that instead of reproducing the acoustic properties of the referent sound as accurately as vocally possible, vocal imitations focus on a few important features dependent on each particular sound category.
What ranges of two-mass model parameters should be used in subject-specific and population-based modeling studies?
Authors: Cook Douglas
Published: November 2016

Two-mass models have been used in voice research for over 40 years. It is therefore both surprising and somewhat troubling that there is no firm consensus regarding the values of model parameters that should be used to represent human phonation. A knowledge of the parameter ranges that can (or should) be used is essential for scientifically valid studies involving population-based or subject-specific modeling. In this study, four techniques were used to examine the ranges of two-mass model parameter values that produce behavior representative of human phonation. The first approach involved a review of values that have been used in previous modeling studies. The second approach utilized unrestricted Monte Carlo sampling to examine which ranges can be used to simulate human phonation. The third approach also utilized Monte Carlo sampling, but parameters were restricted based on physical features of the vocal folds. Finally, a reduction or order technique was developed that allows the determination of two-mass model parameters from the physical features of human vocal folds. Finally, results from each of the four methods were compared and contrasted to provide a better understanding of parameter ranges for two-mass models.
A study of reliability parameters extracted through voice analysis
Authors: Park Hyung Woo , Lee Sangmin
Published: November 2016

The human voice is one of the easiest methods for the information transmission between human beings. The characteristics of the voice can be varied by different people and different situations, such as utterance speed, pitch tone, vocal organ features, and the gender. Moreover, the voice can be used as a factor for deciding the personal credit rating scores. The reliable parameters of speech signal can be extracted from different characteristics of the spoken information. In this paper, we collected the voices from people who has relatively high personal credit scores, and analyzed them.
Working memory facilitates the detection and correction of feedback errors in vocal pitch regulation
Authors: Liu Hanjun , Guo Zhiqiang , Wu Xiuqin
Published: November 2016

In speech processing, information related to the speech motor command and sensory re-afference can be stored in working memory (WM) within a feedback circuit and recalled when needed to adjust the motor activity. Whether WM facilitates the online monitoring of speech motor control, however, remains unclear. The present event-related potential study sought to examine the impact of WM on the auditory-motor processing of pitch feedback errors. Participants sustained a vowel phonation while hearing their voice pitch-shifted + 200 or + 500 cents five times. In the WM task, participants were asked to determine whether the sequence of 5 pitch shifts was different or not between two consecutive vocalizations. In the control task, they did nothing but maintaining their vocalizations steady when exposed to pitch-shifted auditory feedback. The behavioral results revealed a significant increase of vocal responses in the WM task as compared to the control task. At the cortical level, the WM task elicited significantly larger N1 responses and smaller P2 responses than the control task. Taken together, these findings demonstrate the influence of WM on the neurobehavioral responses to pitch-shifted voice auditory feedback, indicating that WM can facilitate the detection and correction of pitch feedback errors in vocal motor control.
Relations on prosody of Japanese back-channeling word “hai” and listener's impression: An investigation with synthesized voices
Authors: Tanahashi Tetsu , Kitahara Tetsuro
Published: November 2016

The back-channeling word “hai” in Japanese is basically used in positive contexts, but it may give a negative impression to the listener if an inappropriate prosody is used. The same thing will occur in human-system dialogues using synthesized voices. Therefore, we investigated the relations on the prosody of synthesized voices of “hai” and the listener's impression. An experiment was conducted using the semantic differential method. Synthesized voices of “hai” were presented with different speaking rates (slow and fast) and different fundamental frequencies (low and high). 16 participants (university students, 8 males and 8 females) rated them on 28 adjective scales. The results were analyzed with the factor analysis, so that four factors were extracted. For the first factor, the loadings of “definite”, “calm”, “active”,etc., were higher than 0.5, so the first factor is considered to represent positiveness. For the second factor, the loadings of “definite,” “violent,” “cold,” and etc., were higher than 0.5, so the second factor is considered to represent unfriendliness. The first factor tends to be higher as the fundamental frequency is lower. The second factor tends to be lower as the speaking rate is higher.
Surface categorical variation In the prosodic marking of English focus
Authors: Royer Adam J. , Jun Sun-Ah
Published: November 2016

This study investigates the variability of focus prosody in English. In intonational phonology of English, focus is known to be marked with a L + H* pitch accent on a focused word followed by deaccenting (Ø) post-focus words (Beckman & Pierrehumbert 1986). 80 speakers participated in a picture naming task where they named images (e.g., blue ball, yellow chair) they saw using the phrase “There was a Adjective1 Noun1, but now there's a Adjective2 Noun2.” Contrastive focus (CF) trials elicited narrow focus on the Adjective2 and Non-contrastive (NC) ones did not. For “a Adjective2 Noun2”, f0 contours were ToBI annotated and various acoustic measurements were taken. Preliminary results indicate that in the CF condition, Adjective2 was most often marked by L + H*, but it is used only 40% of the time. In the other cases, Adjective2 carried either H*, H + !H*, L + !H*, or !H*. The tune used on Adjective2 Noun2 was mainly L + H* Ø, but L + H* !H*, H* Ø, and H + !H* Ø also occurred. These results raise questions about previous claims on phonological marking of focus and the level of tonal representation: what is the phonological status of the various pitch accent types used to mark focus? Are they distinctive or allotones of L + H*?
Appropriateness of acoustic characteristics on perception of disaster warnings
Authors: Ogasawara Naomi , Ofuji Kenta , Harada Akari
Published: November 2016

The appropriateness of acoustic characteristics of speech warnings for natural disasters was examined in this study. Three acoustic parameters (voice gender, speech rate, and pitch) were tested in order to find out the best combination of the acoustics which enhances perceived intelligibility, credibility, and urgency by listeners. A hundred native speakers of Japanese listened to short verbal warnings spoken by a male and a female Japanese speaker with normal pitch, 20 Hz higher, or 20 Hz lower pitch; normal speed, 20% faster, or 20% slower speed. Participants rated each stimulus on 1-to-5-scale. A single effect analysis shows that 1) female voice was perceived with higher credibility and urgency; 2) normal pitch was rated best in the three criteria; and 3) normal speed was perceived best except that faster speed was perceived with higher urgency. A mixed effect analysis found that warnings with the combination of female voice, normal speed, and higher pitch most raised credibility and urgency. Faster speed also raised these two criteria although intelligibility was a little sacrificed. Based on the results, we suggest that disaster warnings with female voice and higher pitch would be effective with the appropriate speaking rate to keep good intelligibility.
Effect of temporal fluctuation in speech on perception of humanness of synthesized speech
Authors: Yokomori Fumiya , Morise Masanori , Ozawa Kenji
Published: November 2016

The sound quality of speech synthesized using modern speech synthesis systems is expected to be approximated to human speech. We investigated the effect of temporal fluctuation of speech on the perception of humanness. Speech stimuli used in the evaluation were generated by voice morphing. The morphing source (morphing rate of 0%) and target (morphing rate of 100%) were speech without temporal fluctuation and original speech, respectively. There were three kinds of morphing factors: fundamental frequency (F0), spectral envelope (SP), and both (F0 + SP). We used MUSHRA as the evaluation method involving two speakers (one male and one female), two phonemes (/a/ and /i/), and two F0s (high and low). Nine morphing rates (every 25% from -100 to 100%) were used, and ten subjects with normal hearing participated in the evaluation. The results show that the stimuli with a morphing rate of 0% scored the lowest humanness for all factors. The stimuli with morphing rates of -100% scored significantly lower than those with a morphing rate of 100% in SP and F0 + SP. The most dominant factor was F0 + SP, and the effect of F0 was the smallest of all factors. [Work supported by JSPS KAKENHI Grant Numbers 15H02726, 16H05899, 16H01734.]
A framework for systematic studies of attitudes in speech
Authors: Fujisaki Hiroya , Ohno Sumio , Gu Wentao
Published: November 2016

We present here a framework for a systematic study of attitudes expressed by speech. Although the term “attitude” is commonly used to refer to phenomena at several different levels, we shall assign separate terms to each of these levels for the sake of clarity. The term “ attitude” can refer both to a person and an object (either concrete or abstract), here we shall be concerned only with personal relationships. Stances: Those (attitudes) related to official relationships, often influenced by social factors together with long-term personal factors (such as commanding, subordinate, etc.) Attitudes (in the narrow sense): Those referring to private but mid- to long-term relationships, often involving the whole personality (such as kind, friendly, remote, etc.) Manners: Those (attitudes) referring to short-term but somewhat consistent individual behaviors/acts (such as polite, rude, abrupt, etc.) For example, when a teacher tries to call the attention of a young child to an imminent danger, his/her utterance will have commanding stance, kind attitude, and abrupt manner simultaneously. Although in real life these distinctions are not always clear-cut, our data collection is based on this principle. The result of a preliminary analysis supports the validity of our approach. [This work was funded by the NSSFC major program 13&ZD189.]
Automatic recognition of negative emotion in speech using support vector machine
Authors: Yamamoto Yuto , Niitsuma Masahiro , Yamashita Yoichi
Published: November 2016

This paper addresses negative emotion recognition using paralinguistic information in speech for speech dialogue system. Speech conveys not only linguistic information but also paralinguistic and non-linguistic information such as the emotions, attitudes, and intentions. This easily perceivable information plays a key role in a spoken dialog system. However, most of previous speech recognition systems fail to consider this significant information, focusing only on linguistic information, thus hindering the development of more natural speech dialog systems. In order to utilize these significant information for speech dialog systems, this paper focuses on negative emotion recognition from Japanese utterances. 6552-dimensional acoustic features were extracted from 6300 Japanese utterances of 50 people in three emotional state: negative; positive; and neutral. Negative emotion includes anger, sad and dislike. While positive emotion includes favor, joy, and relief. They were classified by SVM and evaluated by a 10-fold cross validation. The experimental result showed the recognition rate of 93.4 % for the classification of negative and positive and 95.0% for the classification of negative and neutral.
Assessing the effect of phonetic distance on accommodation
Authors: Tobin Stephen , Gafos Adamantios
Published: November 2016

In investigations of phonetic accommodation, convergence is the most frequently reported finding (e.g., Babel, 2012). However, divergence is also attested under some circumstances (Giles, Coupland & Coupland 1991). On the basis of observations and modeling of Tobin and Nam (2009), Tobin, Nam and Fowler (under review) and Kopecz and Schöner (1995), we asked whether and how phonetic distance along some relevant phonetic dimension would modulate accommodation. Following Roon and Gafos (2014) and Gallantucci, Fowler and Goldstein (2009), who report systematic perceptuomotor effects in speech, we used a cue-distractor paradigm to assess the effect of distance. Participants were visually cued to produce a syllable (ta or ka). 150 ms later they heard a distractor syllable from a 5-step ta or ka VOT-continuum. Participants were assigned continua either near or distant from their baseline VOT. An ordinal logistic regression of data from 12 participants in the near condition indicated patterns of divergence from the mean distractor VOT among those closest to the distractor, convergence among those farthest, and maintenance at intermediate distances. Pending analysis of data from the distant condition, we conclude that targets must fall within a range neither too close to nor too far from speakers' baseline to induce convergence.
A novel method to detect rising and setting tones
Authors: Dwijayanti Suci , Miyoshi Masato
Published: November 2016

Rising or setting tone is a natural phenomenon caused by the chorus emission, which has a discrete frequency time structure and increasing or decreasing frequencies. It usually happens in the Very Low Frequency (VLF) range and sounds like bird tweeting. Since the chorus emission seems to have a clue to space research for safe and secure satellite operations, there is a strong demand to detect such tweeting tone. To this end, we develop a new signal processing tool wherein the running spectra of a tone are first treated as the signals received with individual sensors in a linear senor-array. Then, the estimation of signal parameter via rotational invariance techniques (ESPRIT) algorithm is applied to estimate the rising or setting speed of the tone. In order to evaluate the proposed tool, we conduct simulations using chirp signals of different rising or setting speeds. The simulation results show that the rising or setting speed of a tone can accurately be estimated with the proposed tool.
An analysis of methods for the acoustic localization of unattended aerial vehicles
Authors: Grasing David
Published: November 2016

In this paper methods, models, and difficulties associated with the acoustical detection and tracking of Unattended Aerial Vehicles (UAVs) are presented. The chief advantages of acoustics include passive sensing, the ability to operate in day or night, and relatively low cost. Acoustics also presents several notable challenges including low signal to noise, and issues arising from ground reflections. It is the presence of ground reflections that is explored in particular detail as it presents one of the more unique challenges to this problem. Issues arise because the differences in path length between the line-of-sight and ground reflection arrival of the source are of the same order as the wavelengths of the lower frequencies we are able to detect. Methods for bearing estimation will also be presented, explored, and evaluated in terms of their efficacy. The harmonic structure created by the UAV’s propellers and engines are extracted. Bearings are estimated using various beamforming methods including CB, MVDR, and MUSIC. A black box optimization method based on the Nelder-Mead method on the surface of sphere is presented and used to evaluate different bearing estimation criteria. Finally, bearing estimates at different frequencies are combined via coherent and incoherent methods.
Modified DCTNet for audio signals classification
Authors: Xian Yin , Pu Yunchen , Gan Zhe , Lu Liang , Thompson Andrew
Published: November 2016

We introduced the use of modified DCTNet for audio signals feature extraction. The modified DCTNet is a development of DCTNet, with its center frequencies of filterbanks geometrically spaced. The modified DCTNet is adaptive to different acoustic scales, and it can better capture low frequency acoustic information that is sensitive to human audio perception. We use features extracted by the modified DCTNet and put them to classifiers. Experimental results on bird song classification, music genre classification, and artist identification show that the modified DCTNet and RNN improve classification rate, and achieve state of the art performance.
Analysis of sound propagation in the front region off the east of Tsugaru straits
Authors: Tsurugaya Yoshiaki , Kikuchi Toshiaki , Mizutani Koichi
Published: November 2016

Off the east of Tsugaru straits, located in the north of the main-island, there are three big water masses. One is the Oyashio (Kuril current) that is a cold water mass. Other water masses are the warm water masses: the Tsugaru warm current, and Kurosio extension. And, the Tsugaru warm eddy is made from the Tsugaru warm current on the Oyashio. Therefore, the front is generated in the region to which those water masses bound. The temperature structure changes rapidly in that region. In addition, the bottom depth is changed too. Then, bi-directional sound propagation is analyzed on the line of a right-angled direction to the front that Tsugaru warm eddy is bounded to the Oyashio. It is considered about the sound propagation of 220 km that passes the front from the Tsugaru warm eddy to the Oyashio cold water mass, and the opposite path. In the front region, the sound propagation is changed, and suffers the impact of the bottom at the same time. Therefore, the propagation configuration is different in the bi-directional propagation. The transmission loss in the Tsugaru warm eddy was large when the sound source crosses the front from the Oyashio.
Spatial diversity of ambient noise in the new Arctic
Authors: Schmidt Henrik , Carper Scott , Howe Thomas , Poulsen Andrew
Published: November 2016

The Arctic Ocean is undergoing dramatic changes, the most apparent being the rapidly reducing extent and thickness of the summer ice cover. As has been well established over prior decades, the environmental acoustics of the ice-covered Arctic is dominated by two major effects: the highly inhomogeneous ice cover, and the monotonically upward refracting sound speed profile, the combination of which forces all sound paths to be exposed to strong scattering loss and the associated loss of coherence. In some portions of the Arctic Ocean, however, inflow of warm Pacific water has created the so-called “Beaufort Lens,” a neutrally buoyant high sound velocity layer at 70-80 meter depth, which has dramatically altered the acoustic environment, creating a strong acoustic duct between approximately 100 and 300 m depth. This duct has the potential of trapping sound out to significant ranges (80-100 km) without interacting with the ice cover, resulting in much higher coherence and signal preservation. Acoustic noise measurement results collected with a vertically suspended array during ICEX 2016 illustrate the spatial and temporal noise properties in the presence of this acoustic duct at different depths. Comparisons of the ICEX 2016 data are also made with modeled Arctic noise data. [Work supported by ONR and DARPA.]
Investigating flow noise on underwater gliders acoustic data
Authors: dos Santos Francisco A. , São Thiago Pedro M. , de Oliveira André Luis S. , Barmak Rafael , Lima José Antônio M. , de Almeida Fernando G. , Paula Thiago P.
Published: November 2016

Since November 2015, two underwater gliders equipped with external hydrophones were deployed in the South Brazilian Bight in order characterize the area's soundscape. Contrasting to standard fixed mooring systems (where flow noise is generated by currents passing by the hydrophones), gliders are subject to noise generated by its own downward and upward motion, which may compromise soundscape characterizations if not properly evaluated. In order to investigate induced flow noise on the hydrophone and its characteristics, 563 hours of acoustic data from the gliders were correlated to the navigation settings. Results can be comparable to previous flow noise descriptions for fixed systems. A high correlation was observed between the glider speed (both vertical and total) and 1/3 octave band levels centered at frequencies below 20 Hz. Estimates of the broadband sound pressure level were accomplished with different lower frequency limits and found to be uncorrelated to the glider speed above 40 Hz.
Southern California behavioral response study—Overview and synthesis of results to date
Authors: Southall Brandon L. , Calambokidis John , Friedlaender Ari , DeRuiter Stacy , Stimpert Alison , Goldbogen Jeremy , Hazen Elliott , Moretti David , Allen Ann , Gailey Glenn , Douglas Annie , Schorr Greg , Falcone Erin , Cade Dave , Visser Fleur , Barlow Jay
Published: November 2016

The Southern California Behavioral Response Study (SOCAL-BRS) is an interdisciplinary, multi-team collaboration that uses high-resolution, multi-sensor tags to document behavioral responses of cetaceans to Navy mid-frequency (2.5-5 kHz) active sonar (MFAS). Individual animals are monitored before, during, and after controlled exposure experiments (CEEs) using either simulated or [the first-ever use of] actual U.S. Navy ship-based MFAS. Over 175 tags have been deployed on individuals of ten cetacean species and over 80 CEEs have been conducted. Results including baseline behavioral data, as well as behavioral responses to sound exposure have been published in more than a dozen scientific publications. Behavioral responses to MFAS and other mid-frequency sounds have been documented in several species with changes in diving and feeding behavior and avoidance of sound sources being the most common responses observed, though some individuals did not respond despite relatively high received sound levels. Responses appear to depend on species, exposure context (e.g., behavioral state, prey distribution, proximity to sound sources), and source type (simulated versus real). These experiments provide controlled, scientific measurements of response, or lack of response, that are directly applicable to improving Navy environmental compliance assessments of behavioral response to MFAS.
Effects of industrial tones on bowhead whale calling rates
Authors: Blackwell Susanna B. , Nations Christopher S. , Kauffman Mandy E. , Thode Aaron M. , Norman Robert G. , Kim Katherine H.
Published: November 2016

In summer 2012, exploratory drilling was performed by Shell at Sivulliq, a lease holding in the Beaufort Sea, located within the autumn migration corridor of bowhead whales. The drilling operation involved a number of vessels performing various activities, such as towing the drill rig, anchor handling, and drilling. We aimed to assess the effect of sounds from these activities on bowhead whale calling rates. Acoustic data were collected with six arrays of directional recorders (DASARs) deployed on the seafloor over ~7 weeks in Aug-Oct. Industrial sound was quantified with the use of indices, that measured the presence and amplitude of tones from machinery, or the presence of airgun pulses. For each 10-min period of data collected at each of the 40 recorders, the number of whale calls detected was matched with the “dose” of industrial sound received, and the relationship between calling rates and industrial sound was modeled using negative binomial regression. The analysis showed that with increasing tone levels, bowhead whale calling rates initially increased, peaked, and then decreased. This dual behavioral response is similar to that previously described for bowhead whales and airgun pulses. [Work supported by Shell Exploration and Production Company.]
Opportunistic behavioral-response studies of baleen whales in response to US Navy Sonar Training off Kauai, Hawaii
Authors: Martin Stephen W. , Martin Cameron R. , Matsuyama Brian , Henderson Elizabeth E. , Helble Tyler
Published: November 2016

Opportunistic behavioral responses of baleen whales to disturbances from US Navy mid-frequency active sonar (MFAS) training at the Pacific Missile Range Facility, Kauai, Hawai’i, are being studied utilizing passive acoustic recordings. Automated passive acoustic detection, classification, localization, and tracking analyses of the data have shown a behavioral response in terms of a reduction, or cessation, of minke whale “boing” calling in response to US Navy training during the month of February 2011, 2012, and 2013 over a study area of 3,780 km2. The reduced calling is expressed as reduced minimum densities in the study area by utilizing acoustically localized individual whale counts. In February 2011, the density before sonar training was 3.64 whales while the density during sonar training was 0.69 whales (95% confidence intervals of 3.31-4.01 and 0.27-1.8 whales, respectively). Individual ship-whale encounters have been observed to show cessation of calling from ship approaches without MFAS activity as well as ship approaches with MFAS. Sound Pressure Levels and Cumulative Sound Exposure Levels animals are exposed to are being estimated for evaluation of dose-response relationships. Tracking individual whales allows investigation of kinematics coupled with acoustic call details to establish baseline behaviors for comparison with observations during US Navy training.
Whistle characteristics of newly defined species, the Burrunan dolphin (Tursiops australis), in coastal Victorian waters in Australia
Authors: Wellard Rebecca , Charlton-Robb Kate , Erbe Christine , Wong Bob
Published: November 2016

A newly defined species, the Burrunan dolphin (Tursiops australis), was described in 2011 by Charlton-Robb et al., and is endemic to southern and south-eastern Australian coastal waters. This species' distribution is characterized by small, isolated, and genetically distinct populations. With only two known populations in Victoria, the species is now listed as “Threatened” under the Victorian Flora and Fauna Guarantee Act. Describing and quantifying the vocal repertoire of a species is critical for subsequent analysis of signal functionality, geographic variation, social relevance, and identifying threats associated with anthropogenic noise. Here, we present the first quantitative analysis of whistle characteristics for the species, undertaken on these endemic Victorian populations. Vocalizations of T. australis were recorded during population based surveys in 2007 and 2014 across the Gippsland Lakes and Port Phillip Bay, Victoria. Acoustic parameters of whistles were measured including minimum frequency (fmin), maximum frequency (fmax), start frequency (sf), end frequency (ef), delta frequency (df= fmax-fmin), duration, number of extrema, number of inflection points, and number of steps. We review and compare T. australis whistle features to the two other bottlenose dolphins, T. truncatus and T. aduncus, to assess the similarity and/or differences between the sounds of the three species of bottlenose dolphins.
Position and velocity measurement for moving objects by pulse compression using M-sequence-coded ultrasound
Authors: Hirata Shinnosuke , Hachiya Hiroyuki
Published: November 2016

The pulse-echo method is one of the typical methods for ultrasonic distance measurement. Pulse compression using an M-sequence can improve the SNR of the echo reflected from an object and distance resolution in the pulse-echo method by the cross correlation between the received signal and the reference signal which correspond to the transmitted M-sequence-coded signal. In the case of a moving object, however, the echo is modulated due to the Doppler effect. The Doppler-shifted M-sequence-coded signal cannot be correlated with the original reference signal. Therefore, Doppler velocity estimation by autocorrelation of cyclic M-sequence-coded signal and cross correlations with Doppler-shifted reference signals which correspond to estimated Doppler velocities has been proposed. In this paper, measurement of position and velocity of the static and moving objects by the proposed method using the loud speaker and the microphone array are described. First, the Doppler velocity of the moving object is estimated in each array element. Second, received signals are correlated with the original reference signal for the static object. Then, received signals are correlated with Doppler-shifted reference signals for the moving object. Finally, positions of both objects are determined from the B-mode image formed by the synthetic aperture focusing technique.
Design of a low profile conformal array for transcranial ultrasound imaging
Authors: Smiley Aref , Howell Mark , Fleischman Aaron , Wang Qi , Clement Gregory T.
Published: November 2016

In our ongoing work toward transskull ultrasound brain imaging, we investigate an optically-registered “belt-type” conformal transducer designed to maximize energy transfer while maintaining precise phase control. Previous simulations determined that approximately 500 channels is sufficient for two-dimensional brain imaging by utilizing a tomographic approach valid on irregular boundaries [Clement, Inverse Problems30 125010 (2014)]. The present design is based around an assembly of rigid planar sub-arrays with flexible interconnects. Each piezo-composite sub-array (500 kHz, 1-3 random-fiber, 20 mm X 20 mm) is formed by electroding both faces of the composite before partially dicing the rear surface to produce 19 signal electrode terminals (width~0.85 mm, height~20 mm, and kerf~0.18 mm) with a shared ground face. Sub-arrays are bonded to a custom printed circuit boards and wired to shielded ribbon cable. The full transducer is then created by UV bonding the electrodes to a flexible band, forming the front transducer surface. Length may be customized ~500 elements for an average-sized head. Element performance is assessed by underwater scanned hydrophone characterization. Measurements numerically back-projected to the transducer face indicate good element isolation. Signals through an anatomically-correct full head phantom will be presented as well as the methodology for registering the array to the head using a 3D optical scanner.
Null subtraction imaging: achieving super resolution by imaging with beam nulls
Authors: Reeg Jonathan , Oelze Michael L.
Published: November 2016

Null subtraction imaging (NSI) uses multiple apodizations on receive to create images with low side lobes and super lateral resolution. The first apodization weight has a zero mean when summed across the aperture, placing a null in the beam at broadside. The second apodization simply adds a small DC offset to the first. The third apodization is the transpose of the second. An image created with the zero-mean apodization is then subtracted from the mean of images created with the second and third apodizations. Imaging tasks were performed using a 9L4 array connected to an Ultrasonix RP/SonixDAQ system on an ATS539 phantom containing wire, anechoic and hyperechoic targets. Images were constructed using NSI and compared with rectangular apodization. Image quality was assessed by estimating lateral resolution (-3-dB receive beamwidth), the mainlobe to sidelobe ratio (MSR) in dB and the contrast-to-noise ratio (CNR). NSI provided lateral resolution better than 25 times that of rectangular apodization. The MSR decreased by an average of 29 dB with NSI. However, because the speckle of NSI images become point like, the contrast of the contrast targets were reduced using NSI (e.g., CNR of hyperechoic targets was 1.35 and 0.36 for rectangular versus NSI).
Ultrasonic imaging of sum frequency components by crossed beam contrast echo method
Authors: Kihara Ayane , Kanai Kazumasa , Akiyama Iwaki
Published: November 2016

In a breast cancer diagnosis, the clinical usefulness of the contrast echo harmonic imaging has been reported. The authors proposed a contrast echo method by crossing the two ultrasonic beams to improve the accuracy. The microbubbles in the crossed region re-emit the secondary wave including the sum frequency components. It is capable of discriminating between the echo from microbubbles and the echo from tissue without microbubbles, since the sum frequency are not generated during the nonlinear propagation of primary wave outside the crossed region. Thus the contrast of the resultant image is improved. This study measured the sum frequency components in the echoes from the microbubbles of Sonazoid® in degassed water by using the ultrasonic imaging system with 64 channels. The ultrasonic wave of 5 MHz was transmitted from the array probe of central frequency of 6 MHz equipped with the imaging system. Since the beam formed by the array probe crossed the other beam of 2 MHz at the position 8 cm apart from the probe at 90 degrees, the value of sum frequency is the same as 7 MHz. 7 MHz components in the echo from the microbubbles in the crossed region was observed as 20 dB increased.
Effects of wing flexibility on sound characteristics of a four-wing flapping wing micro air vehicle
Authors: Aono Hikaru , Ozawa Yuta , Yamamoto Makoto , Ishikawa Hitoshi , Kang Chang-kwon , Nonomura Taku , Liu Hao
Published: November 2016

The objective of this study was to understand the sound generation of flapping wings. In particular, the structural properties of the wings were varied to assess the effects of wing flexibility on the sound generation of flapping wings. A four-wing, hummingbird-inspired flapping wing micro air vehicle (FMAV) was considered. The half wing span was approximately six centimeters and the flapping frequency was approximately 25 Hz. The sound produced by the FMAV was measured using a 1/2 inches diameter microphone in an acoustic chamber under the quiescent flow condition. Time-averaged aerodynamic forces were measured by the force and torque sensor Nano17 (ATI Industrial Automation). Results revealed the characteristics of flapping-wing sound in terms of directivity, frequency response, and attenuation. Moreover, the degree of wing deformation led to a variation in the frequency response corresponding to the maximum sound pressure level as well as time-averaged aerodynamic force, even when the flapping frequency was held constant in all the cases. All outcomes of this study would be helpful to control the sound generation of FMAVs and to develop new, silent FMAVs.