bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound systems in reverberant spaces: Approaches in practice
Authors: Woolworth David S.
Published: June 2017

This paper presents three separate case studies of the pairing of sound systems and reverberant spaces, including existing and retrofitted spaces. The design or troubleshooting utilizes various approaches to meet the challenges of reverberant spaces in regard to acoustics, programming of the space, and the use of loudspeakers and processing.
Using the extended techniques on the trombone to demonstrate many of the basic principles of music acoustics
Authors: Plsek Thomas J.
Published: June 2017

The author has realized that the trombone can be used as a low tech device to demonstrate many of the principles of acoustics. This is especially true when one considers all the extended techniques that have been developed for the instrument. A sampling of them could include (but not be limited to) multiphonics creating beats, playing lip buzzes through the various parts of the instrument giving audible information about the signal processing path, mouthpieces slaps to illustrate resonance, inhaling while playing to put an interesting take on brass pedagogy, showing how the water key can indicate the presence of nodes and antinodes and how the instrument provides very little feedback in the extreme high register. Live demonstrations will be presented.
Even weirder than the real thing—Gated reverb history and aesthetics
Authors: Case Alexander U.
Published: June 2017

Sound presented via loudspeaker may take advantage of signal processing to create sounds not possible in an all-acoustic production chain. Breaking free of the acoustic constraints for music-making in the concert hall to take advantage of an analog, digital and electro-acoustic production chain has been a major attraction for many popular recording artists. New aesthetics evolved. Among the most absurd sonic concoctions to come from this, gated reverb is part discovery, and part invention, motivated by misunderstandings, and driven by plain old rock and roll rebellion. This paper tours the development of gated reverb, with audio illustrations, and makes the case for its continued use today.
First international round robin on auralization: Results of the perceptual evaluation
Authors: Brinkmann Fabian , Ackermann David , Aspöck Lukas , Weinzierl Stefan
Published: June 2017

The round robin on auralization aimed at a systematic evaluation of room acoustic modeling software by means of comparing simulated and measured impulse responses. While a physical evaluation by means room acoustical parameters and spectro-temporal comparisons is addressed in an accompanying talk, here, we focus on an evaluation of perceptual differences arising in complex room acoustical scenarios. In these cases, a mere physical evaluation might not be able to predict the perceptual impact of the manifold interaction of different sound propagation phenomena in enclosed spaces such as reflection, scattering, diffraction, or modal behavior. For this purpose, dynamic auralizations of binaural room impulse responses that were simulated with different room acoustical modeling softwares were evaluated against their measured counterparts. For this purpose, listening tests were conducted using “plausibility” and “authenticity” as overall quality criteria and the Spatial Audio and Quality Inventory (SAQI) for a differential diagnosis of the remaining differences.
Interactive reproduction of virtual acoustic environments for the evaluation of hearing devices—Methods and validation
Authors: Grimm Giso , Hohmann Volker
Published: June 2017

Virtual acoustic environments are increasingly used for evaluating hearing devices in complex acoustic conditions. In this talk we propose an interactive simulation method via multi-channel loudspeaker systems or headphones. The method focuses on the time-domain simulation of the direct path and a geometric image source model, which simulates air absorption and in case of motion the Doppler effect of all primary and image sources. To establish the feasibility of this approach, the interaction between reproduction method and technical and perceptual hearing aid performance measures was investigated using computer simulations. Three spatial audio reproduction methods were compared in regular circular loudspeaker arrays with 4 to 72 channels. The influence of reproduction method and array size on performance measures of multi-microphone hearing aid algorithms was analyzed. In addition to the analysis of reproduction methods, algorithm performance was tested in a number of different virtual acoustic environments in order to assess the underlying factors of decreased hearing aid performance in complex environments. The results confirm previous findings that spatial complexity has a major impact on hearing aid benefit, and demonstrate the potential of virtual acoustic environments for hearing aid evaluation. [Funded by DFG FOR1732 “Individualized hearing acoustics.”]
On the numerical simulation of natural acoustic sound sources
Authors: Ackermann David , Böhm Christoph , Weinzierl Stefan
Published: June 2017

A convincing auralization of acoustical scenes does not only require a proper modeling of the sound propagation between source and receiver, but also an appropriate representation of the acoustical source itself. While the properties of electro-acoustic sources can be well represented by advanced loudspeaker formats with high resolution, the complex, time-variant behavior of natural acoustic sources such as speakers, singers or musical instruments is not in any way considered by current techniques for acoustical simulation and auralization. In the talk, we will present measurement results of the sound power and directivity of natural acoustic sound sources and their dependence on pitch and dynamic level, as well as measurements of typical movements of the source during musical performances. We will demonstrate the physical and perceptual relevance of these effects both in the direct field and in room acoustical environments based on a technical and perceptual evaluation, and discuss new approaches to include these effects in numerical simulations.
Acoustical evaluation of the Teatro Colón of Buenos Aires
Authors: Basso Gustavo J.
Published: June 2017

It is been said that the Teatro Colón of Buenos Aires is one of the best halls for opera and symphonic music of the world, and this statement is made mainly for its wonderful acoustics. During the restoration works carried out between 2006 and 2010, we made a lot of studies in order to preserve the acoustical quality of the theater. Among them, we can mentioned acoustical measurements, architectonical examination, statistical analysis, aural descriptions and the development of a digital model of the space. None of the tools used for evaluating the acoustical quality of the hall, mainly based on the parameters of the ISO-3382 Standard, like the acoustical systems proposed by Leo Beranek and Yoichi Ando, was enough to explain the true quality of the room, which was deduced from opinion polls about the perceived sound by the audience. In order to find the causes of its acoustical behavior, we developed an architectural and acoustical study of the hall with the aid of a digital model that can explain, if not all, some of the main characteristics of its particular acoustical field. A synthesis of the results of this evaluation is described in this paper.
Rock art and prehistoric soundscapes: Some results from Italy, France, and Spain
Authors: Díaz-Andreu Margarita , Mattioli Tommaso
Published: June 2017

Under the axis of the SONART project—Sounds of Rock Art. Archaeoacoustics and post-palaeolithic Schematic art in the Western Mediterranean—a series of acoustic tests have been undertaken in seven rock art areas of Italy, France and Spain. The early chronology of this art—Neolithic and Chalcolithic—makes that no information exists about the reasons prehistoric peoples had to produce the art and the beliefs surrounding its creation. This means that in order to check whether sound is related to this cultural manifestation, formal methods need to be used. This also affects the analysis of sound for, in contrast to other areas of the world such as the circumpolar area, no legends or myths can be found to explain the link between art and special reverberation or echoes. Related to the latter, the results of our experiments to assess the direction of arrival (DOA) of echoes will be explained for the rock art landscapes of Valle d’Idivoro (Italy) and Baume Brune (France). The location of rock art in sites where the audibility of the landscape is exceptionally optimal will also be analyzed for the case of the Arroyo de San Serván landscape area in Extremadura (Spain).
Were palaeolithic cave paintings placed because of acoustic resonances?
Authors: Fazenda Bruno M.
Published: June 2017

Previous archaeoacoustics work published from the 1980s to the 2000s has suggested that the location of palaeolithic paintings in French caves, such as Le Portel, Niaux, Isturitz, and Arcy-sur-Cureis, are associated with the acoustic response of those locations, particularly with strong low frequency resonances. Recent work done in caves in the Asturian and Cantabrian regions of Northern Spain has shown some evidence of statistical association between paintings dated from the Aurignacian/Gravettian period (cf. 42,000-25,000 BP) and the existence of acoustic responses which exhibit resonant artifacts. The work presented in this paper reports on a further analysis of the data that explores the association in more detail. A number of metrics focused specifically on low frequency response are used as factors to form statistical models that explain the position of paintings within the caves studied. The results of this study further our understanding on how perception of acoustic response might have played a part in modulating the expressive behavior of our ancestors.
The acoustic of Cumaean Sibyl
Authors: Iannace Gino , Berardi Umberto
Published: June 2017

The Cumaean Sibyl cave is a place in the north of Naples, Italy. The Sibyl was a priestess presiding over the Apollonian oracle; she received the travelers to whom she predicted their future. The cave is length about 140 m, with trapezoidal section excavated in the rock of tuff; the height is about 4.5 m and large about 2.4 m. There is a little room, in the final part of the cave, where according to the legend, the Sibyl received the travelers. The acoustic measurements were done with an omnidirectional sound source in the in the little room and the microphones along the cave. The software for architectural acoustic were used to better understand the sound propagation in the cave. From acoustic measurements and numerical results it emerges that the voice emitted by an orator positioned in the room inside the Sybil cave, is understood in every tunnel point. This paper shows that the legend that this site was an oracle has true acoustical basis.
Acoustic measurements at the sacred sites in Finland
Authors: Rainio Riitta , Lassfolk Kai , Lahelma Antti , Äikäs Tiina
Published: June 2017

In Finland, near the canyon lakes of Julma-Ölkky, Somerjärvi and Taatsijärvi, steep rock cliffs produce distinctive acoustic spaces. On these cliffs, prehistoric rock paintings (5200—500 BC) as well as an ancient Sami offering site (cf. 1100—AD) can be found. Ethnographic sources describe that the Sami used to sing and listen to echoes while making offerings there. This paper presents the results of an archaeoacoustic project that seeks to explore the role of sound in the development and use of these archaeological sites. The applied methods include multichannel impulse response recording, angle of arrival estimation of early reflections, spectrum analysis, digital image processing, and 3D laser scanning. On the basis of the analyses, we have concluded that the cliffs that have been painted or held as sacred are efficient sound reflectors. They create discreet echoes and, accordingly, phantom sound sources. Especially at the Värikallio cliff, the sound appears to emanate directly from the painted figures. These results, together with previously unnoticed drumming figures in the Värikallio painting, provide a clue to the significance of the sound rituals at these sacred sites.
A theoretical framework for archaeoacoustics and case studies
Authors: Waller Steven J.
Published: June 2017

Application of black box theory is proposed as a theoretical framework for archaeoacoustic studies. First, input/output analysis can be applied to archaeological sites, in which the physical characteristics of a site serve as a black box to physically transform initial sonic inputs directly into various acoustic output phenomena that can be quantitatively measured, such as reflected repeats, resonance, etc. In turn, acoustic output from the first (archaeological) black box serves as input for a second black box: the human mind. Examples are presented to support the argument that the psychoacoustics of sound perception is/was a crucial aspect of archaeoacoustics. Cognitive response is heavily influenced by culture, expectations, and subjective values attributed to various sounds. Outputs of the second (cognitive) black box that can be analyzed include tangible archaeological manifestations such as rock art, megaliths, etc., as well as intangible responses such as orally recorded myths, traditions, rituals, and beliefs. Analysis of each of the input/output components from these two coupled black boxes can reveal important interrelationships between initial sonic inputs, sound transforming characteristics of archaeological sites, and the cognitive responses of ancient artists and architects to those transformed sounds. Case studies are presented to illustrate application of this theoretical approach.
Long-term monitoring of cetacean bioacoustics using cabled observatories in deep-sea off East Sicily
Authors: Caruso Francesco , Sciacca Virginia , Alonge Giuseppe , Bellia Giorgio , Buscaino Giuseppa , De Domenico Emilio , Grammauta Rosario , Larosa Giuseppina , Mazzola Salvatore , Pavan Gianni , Papale Elena , Pellegrino Carmelo , Pulvirenti Sara , Simeone Francesco , Speziale Fabrizio , Viola Salvatore , Riccobene Giorgio
Published: June 2017

The EMSO Research Infrastructure operates multidisciplinary seafloor-cabled observatories in a deep-sea area offshore Eastern Sicily (2100 m of depth). In a data-lacking zone, Passive Acoustic Monitoring activities revealed new information on cetacean bioacoustics over multiple ecological scales. Expert operators investigated the presence of cetacean vocalizations within the large acoustic datasets acquired. Then, algorithms were developed to provide information on the behavior and ecology of the recorded species. In 2005-2006, the acoustic activity of toothed whales was investigated through the OvDE antenna (100 Hz to 48 kHz). The assessment of the size distribution of sperm whales was acoustically possible and the tracking of the animals showed the direction of movement and the diving profile. The biosonar activity of dolphins resulted mostly confined in the nighttime, linked to seasonal variation in daylight time and prey-field variability known for these deep-pelagic waters. Furthermore, in 2012-2013, we monitored the annual acoustic presence of fin whales thanks to the NEMO-SN1 station (1 Hz to 1 kHz). The results showed that the species was present throughout all seasons, with peaks in call detection rate during spring and summer months, and that the fin whale calls were mostly detected in low background noise conditions.
Polar coastal soundscapes: Tridimensional mapping of benthic biophony and ice geophony with a compact sensor array
Authors: Lossent Julie , Gervaise Cedric , Chauvaud Laurent , Jolivet Aurélie , Mathias Delphine , Mars Jérôme
Published: June 2017

Polar areas show fast changes linked to global warming. The reduction of the ice pack and the melting of the ice sheet modify the conditions of living of marine fauna. We propose the simultaneous monitoring of the ice and benthic fauna using passive acoustics. Thanks to a compact sensor array of 4 hydrophones (2m*2m*2m), we detected, localized and mapped in three dimensions ({azimuth, elevation} or {x, y, z}) the biophonic and geophonic contributions made up of short and wideband pulses. Tridimensional maps of benthic biophony and ice geophony of Antarctic and Arctic 7 days-long recording sessions (2015, 2016) are built and analyzed over a surface of the order of 1 km2. Benthic invertebrates emit high energetic pulses with peak frequencies ranging from 2 to 55 kHz, most of them below 15 kHz. Geophony is structured into two parts. The ice sheet, located several kilometers or tens of kilometers away, creates a stable spatial distribution of low energetic pulses (representing the majority of pulses in the soundscape) modulated by the temporal variability. The movements of isolated icebergs or pack ice produce localized acoustic events identifiable by the high sound levels and the stable peak frequencies of the emitted pulses.
Acoustic habitat utilized by ice-living seals: Hearing and masking in natural noise environments
Authors: Sills Jillian , Reichmuth Colleen , Whiting Alex
Published: June 2017

Acoustic habitat is a fundamental but poorly understood resource for marine mammals, including seals. To evaluate the soundscapes experienced by seals in dynamic Arctic environments, two DSG-Ocean Acoustic Dataloggers were deployed in Kotzebue Sound, Alaska from September 2014 through September 2015, providing a full year of acoustic coverage for this region of the Chukchi Sea. The recorders were placed in an area of seasonal fast ice where spotted, ringed, and bearded seals are all found at various times of year. The data describe the acoustic conditions typically experienced by these ecologically and culturally important seal species, including variations in noise up to 48 kHz within and across scales of hours, days, months, and seasons. The noise profiles provide an ecological framework for laboratory studies of hearing with trained seals, allowing for improved understanding of their sensory biology in the context of their acoustic habitat. The integration of these noise measurements with hearing and auditory masking data enables a quantitative assessment of the effects of varying ambient noise conditions on the communication ranges of seals living in Arctic waters. [Work supported by the Northwest Arctic Borough Science Committee.]
Acoustic and biological trends on coral reefs off Maui, Hawaii
Authors: Kaplan Maxwell B. , Lammers Marc , Mooney T Aran , Zang Eden
Published: June 2017

Coral reef soundscapes comprise a range of biological sounds. To investigate how the sounds produced on a given reef relate to the species present, 7 Hawaiian reefs that varied in their species assemblages were equipped with acoustic recorders operating on a 10% duty cycle for 16 months, starting in September 2014. Benthic and fish visual surveys were conducted 4 times over the course of the study. Acoustic analyses were carried out in 2 frequency bands (50-1200 Hz and 1.8-20.5 kHz) that corresponded with the spectral features of the major sound-producing taxa on these reefs, fish and snapping shrimp, respectively. In the low-frequency band, the presence of humpback whales (December-May) was the major driver of sound level, whereas in the high-frequency band sound level closely tracked water temperature. On shorter timescales, the magnitude of the diel trend varied in strength among reefs, which may reflect differences in the species assemblages present. Regression trees indicated that, at low frequencies, the relationship between species assemblages and acoustic parameters varied by season; however, at high frequencies, a given reef was generally most like itself over time. Thus, long-term acoustic recordings can capture and distill the substantial acoustic variability present in coral reef ecosystems.
Noise affects black-tufted marmoset (Callithrix penicillata; GEOFFROY, 1812) phee call frequency
Authors: Santos Sara , Duarte Marina H. , Cardoso Isabela F. , Sousa-Lima Renata S. , Young Robert J.
Published: June 2017

Anthropogenic noise is very different from natural sounds, and could cause organisms living in noisy areas to modify their vocal communication. We assessed the influence of noise on black tufted-ear marmoset acoustic communication. Spontaneously produced phee vocalizations were recorded in two areas: a noisy urban park, located in Belo Horizonte, Minas Gerais state, Brazil and a quiet natural forest, located at Cauaia in Matozinhos, in the same state. We also recorded bus brakes sounds (BBS) in the noisy park because we noticed that the sounds produced by these vehicles were similar to the phee vocalizations. Frequencies and duration of phees and the BBS were measured and used to compare: 1- pheesfrom the urban and natural areas and 2- urban phee vocalizations and BBS. The duration of the phee calls was longer in the urban area. The low, high and dominant frequencies were significantly higher in the natural area. The low frequency extracted from BBS was similar to those of the phee calls of marmosets in the urban area. We suggest that the difference between the marmoset calls from urban and natural areas is influenced by noise and BBS compete with marmosets calls and may disturb the communication of these primates.
Vocal behavior and ontogeny of Northern right whales in the southeast critical habitat
Authors: Gerstein Edmund R. , Trygonis Vasilis , Moir James B.
Published: June 2017

North Atlantic right whales are one of the most endangered of the great whales. A remnant population of ~500 inhabits the eastern seaboard of North America. A small fraction (2%) travels south to their critical calving habitat along the Florida and Georgia coast. By late November and through the winter, right whales give birth and nurse their calves in these shallow waters before departing in early spring to their northern habitats. In the southeast critical habitat mother-calf pairs remain generally isolated from other whales, presenting a unique platform to study vocal development and learning in large whales. Using small boats, GPS-instrumented, free-drifting autonomous acoustic buoys were deployed in close proximity to 44 photo-identified mother-calf pairs over 7 calving seasons. Surface video and synchronized underwater recordings documented their social and vocal behavior. With the exception of some low-energy gunshot sounds, mothers, and their calves, remained predominantly silent during the first 4 weeks. This might be due to calf maturation, and or a strategy to avoid harassment by other whales or potential predators. Over 100 calls have been analyzed from 15 different calves. Some of these calves were resampled at different stages at <1 week up to 12 weeks of age. Evidence of individual and age-related variance and changes in call structure, complexity, power, rates, as well as vocal mimicry are presented. [Funding: HBOI Florida PFW License Plate Fund, The Harry Richter Foundation and IBM, NOAA Permit #14233.]
Characterizing soundscapes and larval fish settlement in tropical seagrass and mangrove habitats
Authors: Jones Ian T. , Suca Justin , Llopiz Joel , Mooney T. Aran
Published: June 2017

Recent evidence suggests soundscapes of coral reefs may provide acoustic cues that larval reef fish utilize during settlement. Seagrass and mangrove habitats are further important refuges for larvae and juveniles of many fishes; however, compared to reefs, less is known about the characteristics of tropical seagrass and mangrove soundscapes and their potential as settlement cues. We deployed light traps to assess fish larvae settlement and passive acoustic recorders to study the “ecoacoustics” at mangrove, seagrass, and coral reef sites around two bays in St. John, U.S. Virgin Islands. Light traps were deployed nightly around the third quarter and new moon, and 24 h periods of acoustic recordings were taken during the same time. Fish larvae were counted and identified to the lowest possible taxonomic level. Focusing on biotic soundscape components, diel trends in metrics such as sound pressure level, power spectral density, and snap counts of snapping shrimp were assessed. Although what role mangrove and seagrass soundscapes may play in fish settlement remains unclear, these soundscape and larval settlement data provide foundations for deeper investigations of the relationship between acoustic and larval ecology in these essential nursery habitats.
Toward an unsupervised and automated analysis framework for large acoustic datasets to assess animal biodiversity and ecosystem health
Authors: Shiu Yu , Rahaman Ashakur , Clark Christopher W. , Klinck Holger
Published: June 2017

Passive acoustic monitoring is a promising and non-invasive method to assess the biodiversity and potentially health of terrestrial and marine ecosystems. Over the last decade, various methods have been proposed to extract information on the animal biodiversity primarily based on acoustics indices. Several recent studies have shown that ecological relevance and effectiveness of these indices remain uncertain. We propose a new, multi-step method to estimate animal biodiversity from acoustic datasets by applying an unsupervised detection and classification technique. Our semi-automated framework extracts every acoustic event with a pre-defined signal-to-noise ratio. In a second step, the detected events are grouped into classes based on the similarity of acoustic features. The number of resultant classes are linked to animal biodiversity in an area by applying a transfer function, which is established using manually/expert reviewed class labels. Our framework provides diel and seasonal changes in the overall number of sound classes as well as number of acoustic events in each class. We will demonstrate its performance by application to three datasets collected in the Chukchi Sea, Alaska, Sapsucker Woods Sanctuary, Ithaca, NY, and Abel Tasman National Park, New Zealand.
Using automated acoustic monitoring to detect elevational migration in the avian community of the Gondwana Rainforests of Australia
Authors: Leach Elliot , Burwell Chris , Jones Darryl , Kitching Roger
Published: June 2017

Climate change presents the most significant threat to Australia's rainforest avifauna. In order to determine the future impacts of climate change and make informed conservation decisions, baseline information on species distributions, elevational preferences, and seasonal movements is necessary. Traditionally, generating data such as these over large spatio-temporal scales has been difficult and costly. However, the recent development of cheap, reliable bioacoustic recorders has facilitated such data collection. By using automated acoustic recorders in subtropical rainforest along two elevational gradients in northern New South Wales, Australia, we were able to continuously monitor the avian community for a 14-month period. The data generated during this project allowed us to detect seasonal elevation migration amongst resident species, the arrival and departure times of migratory species and the breeding behavior of cryptic species. This research also represented the first comprehensive avian biodiversity survey conducted in the region. Here, we present our results from the automated acoustic monitoring, and discuss the implications for future research and monitoring of the avian community in the Gondwanan Rainforests of Australia.
Large scale passive acoustic monitoring using compact arrays of synchronized hydrophones
Authors: Urazghildiiev Ildar R. , Hannay David E.
Published: June 2017

Modern and future ecosystem-level data processing techniques need to solve the problem of detecting, classifying, localizing, tracking, and estimating density (DCLTDE) concurrently from all sounds an acoustic recorder detects. To solve this problem, we propose a technique based on three major components: the compact array of synchronized hydrophones; the automatic DCLTDE technique; and the software to visualize and to rapidly analyze the results of long-term data processing. The compact array provides an additional information about the azimuth and elevation angles of the detected sounds, and the data processing technique uses this information to solve the required DCLTDE problems automatically. Processed acoustic recordings collected over one year in the Strait of Georgia, BC, Canada, are presented. These results demonstrated that the proposed technique dramatically increases the efficiency-to-cost ratio by decreasing the time needed for a person to analyze a huge amount of data and by increasing the amount and accuracy of the information extracted from acoustic recordings.
Acoustic detection of macroalgae in a dynamic Arctic environment. Isfjorden (West Spitsbergen) case study
Authors: Kruss Aleksandra , Wiktor Jozef , Tatarek Agnieszka , Wiktor Jozef
Published: June 2017

Acoustic imaging of seabed morphology and benthic habitats is a fast-developing tool for investigating large areas of underwater environment. Even though single- and multi-beam echosounders have been widely used for this purpose for many years, there is still much to discover, especially in terms of processing water column echoes to detect macroalgae and other scatterers (e.g., fishes, or suspended sediments) that can provide us with important information about the underwater environment and its evolution. In difficult Arctic conditions, acoustic monitoring plays an important role in the investigation of bottom morphology and in imaging habitats. In July 2016, we carried out a multidisciplinary expedition to investigate macroalgae spatial distribution in Isfjorden and to measure significant environmental features (currents, salinity, turbidity) influencing their occurrence. An area of 4.3 km² was mapped using single- and multi-beam sonars along with underwater video recordings, CTD and ADCP measurements. We obtained a unique data set showing variability of acoustic properties among different macroalgae species, supported by very well correlated ground-truth data and environmental measurements. Modern processing techniques were used to analyze water column data signals for kelp detection. This study presents efficient tools for monitoring benthic communities and their environmental context, focusing on macroalgae acoustic characteristics.
Internal wave effects on seafloor imagery and bathymetry estimates
Authors: Lyons Anthony P. , Hansen Roy E. , Prater James , Connors Warren A. , Rice Glen , Pailhas Yan
Published: June 2017

Large linear structures (tens of meters by several meters) have been observed recently in seafloor imagery and bathymetry collected with both synthetic aperture sonar (SAS) and multibeam echosounder (MBES) systems. It has been suggested [Hansen, et al., IEEE J. Oceanic Eng., 40, 621-631 (2015)] that this phenomenon is not due to the true morphology of the seafloor, but is caused by water column features related to breaking internal waves. Changes observed in acoustic intensity and bathymetry estimates are caused by a focusing of the acoustic field which results in structures that appear to be true seabed topography. In terms of seafloor mapping, these topography-mimicking features will impact the interpretation of imagery, may complicate the production of mosaics, and have the potential to cause bathymetric uncertainties exceeding International Hydrographic Organization standards. In this talk we will show that these water-column caused features may not be uncommon using examples of data collected with several different SAS and MBES systems in a variety of experimental locations.
Seafloor mapping with a cylindrical array
Authors: Rice Glen , Gammelseter Ole Bernt , Weber Thomas C.
Published: June 2017

Seafloor mapping is conducted with different types of arrays. Single beam mapping systems are often constructed with piston arrays. Linear arrays are used for both side scan sonar and for multibeam echo sounders. These conventional approaches to seafloor mapping are typically constrained to a single observation of any one point on the seafloor for any one pass of a moving vessel. A less conventional cylindrical array offers the opportunity to observe the majority of the seafloor from different perspectives but with the same angle with a single pass. This has the potential to improve the resulting depth estimates and seafloor backscatter products. In 2016, a Simrad Omnisonar was used to demonstrate seafloor mapping with a cylindrical array. While this array is designed for observing fish schools, a small area was successfully mapped and the results compared with a conventional bathymetric mapping system. Observations on the benefits and challenges of this approach to seafloor mapping will be discussed.
Improving seep detection by swath sonars with adaptive beamforming
Authors: Lønmo Tor Inge B. , Weber Thomas C.
Published: June 2017

Detection of gas seeps is currently of interest for a wide variety of applications. The oil and gas industry can use it to monitor their installations, e.g. oil wells and pipelines. It may also contribute to the understanding of geological and biological activity in the seabed. In a climate perspective, it is also important for estimating the amount of methane that seeps into the atmosphere and monitoring CO2 stored in geological structures. Seeps are commonly detected by bathymetric swath sonars. Bubbles are strong acoustical targets and may form clear flares in the water column display, depending on the size and density of the bubbles. Detection is often easy before the first bottom return arrive and is gradually masked by the seafloor reverberation at longer ranges. We propose to use the sidelobe suppressing properties of adaptive beamforming to suppress seafloor reverberation and extend seep detection range. To investigate this in practice we placed an artificial seep at approximately 45 m depth and mapped it with a swath sonar. We ran lines over the seep at between 0 and 80 m horizontal range. Our processing chain allows us to process each ping with both standard and adaptive beamforming, providing easily comparable results.
Paradigm shift of underwater echo sounding technology III—Evaluation of paradigm shift echo-sounder
Authors: Matsuo Ikuo , Sasakura Toyoki
Published: June 2017

Underwater echo sounding technology was developed 65 years ago and has been applied to various systems such as fishfinder, bathymetry, sonar, side scanning sonar, multi beam echo sounding system and synthetic aperture sonar. We have suggested a new concept that may change the history of underwater echo sounding technology, should be called as “Paradigm Shift.” In the conventional system, the transmission intervals are always longer than the time of the round trip distance to the target divided by the underwater sound velocity. By adapting our new “Paradigm Shift Echo-sounder” into the system, the transmission intervals can be decided except for depending on a target and it will be possible to conduct a bathymetry survey that transmits 100 times per second. The system utilized the 7th order Gold code sequence signals. Transmitting signal is the phase modulated and four cycles of carrier signals as one bit of the Gold code sequence. The actual sea trial experiment was done by the proto type of “Paradigm Shift Echo-sounder.” The experimental result was obtained by the transmission of 100 times per second at the depth of 10 to 80 m sea bottom. We also confirmed that this system could reconstruct a high-resolution echogram of the artificial reef.
Standards for pressure pulses used in lithotripsy, pain therapy, and other medical applications
Authors: Ueberle Friedrich
Published: June 2017

Shockwave lithotripsy was first used in 1980 for the non-invasive, safe treatment of stones in the urinary tract. The first commercial lithotripters were introduced in 1983, using an underwater spark discharge as sound source, which was focused by an ellipsoidal mirror. Single steep (Shockwave) pressure pulses of few microseconds duration with 20…>100MPa amplitude are released at a rate up to 2 per second. Each treatment requires ca. 1000 to 3000 pulses. Competitors developed lithotripters with spherical piezoelectric and focused electromagnetic sources. Up today, these three source types are applied in commercial lithotripters. With the occurrence of different types of sources from different manufacturers, it became important to standardize the description of pulses and acoustic wave fields, for clinical approval and safety, the understanding of pressure pulse interaction with biological tissue and stones, and for quality control. A lithotripter safety standard was created 1997 (IEC601-2-36). In 1998, the international standard IEC61846 was released, which describes measurement methods and parameters for focused pressure pulse sources. Both standards are regularly reviewed and enhanced in maintenance projects. A new project (IEC63045) defines parameters for non-focusing and weakly focusing pressure pulse sources, which are widely used in pain therapy and other tissue applications since 1998.
Fast accurate optical measurement of medical ultrasonic field in combination with numerical simulation of nonlinear propagation
Authors: Umemura Shin-ichiro , Yoshizawa Shin
Published: June 2017

Fast and accurate measurement of ultrasonic field is necessary to ensure the safety and efficacy of therapeutic as well as diagnostic applications of medical ultrasound. The most common method for the purpose is hydrophone scanning. However, it requires a long scanning time and potentially disturbs the field, which is limiting the efficiency of developing such applications. This study proposes an optical phase contrast method in combination of a CT algorithm. Ultrasonic pressure field modulates the phase of the light passing through the field. A phase plate was employed to shift the phase of the non-diffracted component of the light typically by 90 degrees. The phase modulation of the diffracted component was converted to amplitude modulation through interference with the phase-shifted non-diffracted component and then measured by camera. From the measured projected 2D data, the 3D pressure field was reconstructed by a CT algorithm. An upstream field, in which the optical phase does not wrap and the effect of nonlinear propagation can be ignored, was thereby quantified. Nonlinear ultrasonic propagation was simulated based on a pseudo spectral method using the upstream pressure field as the input. Both pressure waveform and absolute pressure from the proposed method agreed well with those directly from hydrophone scanning.
Acoustic holography combined with radiation force measurements to characterize broadband ultrasound transducers and calibrate hydrophone sensitivity
Authors: Tsysar Sergey , Kryzhanovsky Maxim A. , Khokhlova Vera , Kreider Wayne , Sapozhnikov Oleg
Published: June 2017

Accurate characterization of broadband ultrasound (US) transducers operating either in pulsed or CW modes is necessary for their use in biomedical applications. The acoustic holography method allows reconstruction of the pattern of vibrations at the transducer surface for use as a model boundary condition to simulate ultrasound fields in water or tissue. A calibrated hydrophone is often not available to perform such measurements. Here, it is proposed to combine transient acoustic holography with radiation force balance (RFB) measurements at multiple frequencies to quantitatively determine 3D distributions of the acoustic field at different source frequencies, the corresponding acoustic power of the source, and the hydrophone sensitivity within the frequency bandwidth of the transducer. First, a transient acoustic hologram is measured using a short-pulse excitation of the source by raster scanning the hydrophone along a surface in front of the source and recording the waveform at a large number of points (typically 10-40 thousand). Then, RFB measurements are conducted for different frequencies within the pulse bandwidth to determine axial component of the acoustic radiation force. These data are related to the corresponding values calculated from the holograms at each frequency component to determine the corresponding hydrophone sensitivities. [Work supported by RSF-14-12-00974.]
Use of acoustic holography to quantify and correct geometrical errors in ultrasound field characterization
Authors: Kreider Wayne , Khokhlova Vera , Tsysar Sergey , Sapozhnikov Oleg
Published: June 2017

The development of medical ultrasound devices requires characterization of the ultrasound fields they radiate. Recently, acoustic holography methods have gained increased acceptance for field characterization. Because such an approach allows reconstruction of the full 3D field, the beam axis, its orientation relative to the positioner, and any field quantities of interest can be readily determined. Inherently, the accuracy of such projection methods can be sensitive to uncertainties in the positions at which field measurements are recorded. Although commonly used industrial positioning systems have linear axes with repeatability specifications much less than an ultrasound wavelength, the assembled orthogonality of three linear axes is not guaranteed. Here we analyze a typical raster scanning holography experiment by considering two distinct coordinate systems: ideal rectilinear coordinates aligned with the transducer (1.2 MHz, aperture 124 mm, F-number 1) and non-orthogonal coordinates aligned with the positioner (Velmex Unislides). By locating a distinct field feature in both projection calculations and independent hydrophone measurements, a misalignment of positioner axes of about 0.50 was identified. The impact of positioner non-orthogonality on field characterization metrics is discussed along with the potential use of this approach for a priori positioner calibration. [Work supported by NIH EB007643, NIH EB016118, and RSF-14-15-00665.]
Use of wide-element one-dimensional receiving arrays to measure two-dimensional lateral pressure distribution of ultrasound beams
Authors: Sapozhnikov Oleg , Kreider Wayne , Maxwell Adam D. , Khokhlova Vera
Published: June 2017

Measurement of acoustic fields is an important aspect of ultrasound research and development. The corresponding data is usually collected by a raster scan using a single point receiver moved by a computer-controlled positioning system. A faster approach could be based on the use of a 1D linear multi-element array with several tens or hundreds of small elements, which is moved in a direction perpendicular to the beam axis. The drawback of such an approach is difficulty in making small, closely-positioned receiving elements that provide sufficient signal-to-noise ratio. The current paper presents an alternative design for a 1D linear array: instead of using small elements, here it is suggested to use narrow but long elements, with a width on the order of a half wavelength or less and a length larger than the extent of the ultrasound beam being studied. The drawback of the proposed long-element arrays is absence of resolution in the direction along the element. This problem is solved by incrementally rotating the array either around the axis parallel to the array surface and perpendicular to the elements or around the axis perpendicular to the array surface. [Work supported by RSF 14-15-00665, NIH R01 EB007643, and NIH R21 EB016118.]
Ultrasound triggered mRNA delivery to dendritic cells—Towards an in vivo cancer vaccination strategy
Authors: Dewitte Heleen , Stock Emmelie , Vanderperren Katrien , De Smedt Stefaan , Breckpot Karine , Lentacker Ine
Published: June 2017

Increasing knowledge on the crucial role of dendritic cells (DCs) in the initiation of immunity has launched a new field in cancer immunotherapy: DC vaccination. By loading patient’s DCs with tumor antigens and injecting them as a vaccine, antitumor immune responses can be induced. This project aims to use theranostic mRNA-loaded MBs for ultrasound-guided, ultrasound-triggered antigen-loading of DCs within the lymph nodes in vivo. mRNA-loaded MBs were prepared by attaching mRNA-lipid complexes to lipid MBs via avidin-biotin linkages. MBs loaded with mRNA encoding a tumor antigen (ovalbumin, OVA) were used to sonoporate murine DCs in vitro. These mRNA-sonoporated DCs were then used as therapeutic vaccines in E.G7-OVA-bearing mice. In vitro mRNA-sonoporation of murine DCs revealed transfection efficiencies up to 27%. The potential of this technique was further assessed in vivo by vaccinating E.G7-OVA-bearing mice with sonoporated DCs. When mRNA-sonoporated DCs were used, tumor growth was significantly reduced and even regressed in 30% of the animals. Moreover, rechallenge with tumor cells did not lead to tumor growth, indicating long-lasting immunological protection. A CEUS study in dogs showed the MBs rapidly drained to the lymph nodes after sc injection. Moreover, this revealed detailed information on the lymphatic anatomy.
Enhanced delivery of a density-modified therapeutic using ultrasound: Comparing the influence of micro- and nano-scale cavitation nuclei
Authors: Lea-Banks Harriet , Mannaris Christophoros , Grundy Megan , Stride Eleanor P. , Coussios Constantin
Published: June 2017

New strategies are required to enhance the penetration and tumor-wide distribution of cancer therapeutics, including viruses, antibodies, and oligonucleotides. We have shown previously that increasing the density of a nanoparticle can enhance its ultrasound-mediated transport, particularly when exposed to microstreaming. The current study investigates how the physical characteristics and dynamics of different cavitation nucleation agents affect the cavitation-mediated transport of therapeutics not directly bound to the gas nuclei. SonoVue (Bracco, Milan, Italy) microbubble contrast agent (with 3 μm mean initial bubble diameter) and polymeric gas-entrapping nanoparticles (with 260 nm mean initial bubble diameter) were first compared in terms of inertial cavitation threshold and cavitation persistence. Under the same ultrasound exposure conditions (centre frequencies of either 0.5 MHz or 1.6 MHz, and peak negative pressures from 0.2 MPa to 3.5 MPa) their respective cavitation emissions were found to differ in magnitude, frequency composition and duration. The resultant penetration depths of co-injected gold-coated nanoparticles in a tissue-mimicking phantom were also found to vary, with the polymeric gas-entrapping nanoparticles giving rise to greater penetration distances. This study concludes that both the characteristics of the therapeutic and the cavitation nuclei can significantly influence ultrasound-mediated drug delivery.
Comparative lytic efficacy of rt-PA and intermittent ultrasound in porcine versus human clots
Authors: Huang Shenwen , Shekhar Himanshu , Holland Christy
Published: June 2017

Porcine thrombi are employed routinely in preclinical models of ischemic stroke. In this study, we examined the differential lytic susceptibility of porcine and human whole blood clots to recombinant tissue-plasminogen activator (rt-PA) and the adjuvant use of an echo contrast agent, Definity®, and intermittent 120 kHz ultrasound to enhance thrombolysis. An in vitro system equipped with time-lapse microscopy was used to evaluate rt-PA lysis of porcine and human clots in same species or cross species plasma. The rt-PA lytic efficacy observed for porcine clots in porcine plasma was 22 times lower than for human clots in human plasma. Porcine clots did not exhibit increased lysis with adjuvant Definity® and ultrasound exposure. However, the rt-PA lytic susceptibility of the porcine clots in human plasma was similar to that of human clots in human plasma. Human clots perfused with porcine plasma did not respond to rt-PA, but adjuvant use of Definity® and ultrasound enhanced lysis. These results reveal considerable differences in lytic susceptibility of porcine clots and human clots to rt-PA, and highlight the limitations of current porcine models used to develop clinical thrombolytic therapies.