bluuebunny/crossref_metadata_2025 huggingface dataset:
Scattering enhancements for partially exposed cylinders at a free surface caused by Franz waves: Measurements and geometric model
Authors: Eastland Grant C. , Marston Philip L.
Published: September 2012

Creeping waves on solid cylinders having slightly subsonic phase velocities and large radiation damping are usually described as Franz waves because of their association with complex poles investigated by Franz. For free-field high frequency broadside backscattering in water, the associated echoes are weak due to the radiation damping. It is demonstrated here, however, that for partially exposed solid metal cylinders at a free surface viewed at grazing incidence, the Franz wave echo can be large relative to the specular echo even for ka above 20 when the grazing angle is sufficiently small. The reason is that at small grazing angles and small exposures, the Fresnel zone associated with the specular echo is occluded so that the specular echo is weak [K. Baik and P. L. Marston, IEEE J. Ocean. Eng. 33, 386 (2008)] while the Franz wave is partially reflected at the interface. This has been confirmed from the evolution of echo timing with cylinder exposure and by SAS imaging. In the experiment a solid cylinder was slowly lowered through the free surface into the water. In bistatic scattering a Franz echo can be present with small exposure without the Franz wave reflecting from the free surface. [Supported by ONR.]
The acoustics of pianos
Authors: Chaigne Antoine J.
Published: September 2012

The manufacturing of pianos remains largely empirical, with numerous trial-and-error procedures and fine adjustments at each step of the building process. The “skeleton” of the instrument obeys fundamental principles of vibrations, acoustics, and material science. An abundance of literature is available on its different constitutive parts. However, scientific studies based on a global model of the instrument that connects all of these constitutive parts together are more recent. Such modeling sheds useful light on the essential coupling properties between elements and, in particular, on the string-soundboard coupling at the bridge, and on the radiation of the soundboard. Fine analysis of piano tones also shows that in most cases, a nonlinear model of the strings is necessary to account for perceptually significant features such as precursors in the time-domain and the so-called “phantom partials” in the spectrum. This nonlinearity is based on the coupling between transverse and longitudinal waves in the string. In this lecture, a time-domain model of a complete piano is presented that couples together nonlinear strings, soundboard vibrations, and radiation in air. It highlights the transmission of both transverse and longitudinal string forces to the soundboard, and the influence of rib design and bridge on soundboard mobility and radiation patterns. Comparisons between the results of the model and measurements made on real pianos will be discussed.
Sound quality from binaural and multidirectional measurements
Authors: Griesinger David H.
Published: September 2012

There has been rapid progress in methods to gather binaural and multi-directional point-to-point impulse responses from unoccupied venues. With individual matching of headphones to a listener this data can sometimes be auralized to obtain a glimpse of the sound of a venue. But numerical methods to analyze such data in order to quantify the precise sound of a particular seat remain elusive. This paper will discuss some of the limitations of point measurements, recent work on binaural technology, and impulse response analysis techniques that are not based on sound energy, but on the methods used by the ear and brain to aurally perceive music, speech, and sonic environments. The goal - nearly in sight - is developing methods for obtaining objective quality assessments from binaural or multidirectional recordings of live music and speech.
Using a higher-order spherical microphone array to assess spatial and temporal distribution of sound in rooms
Authors: Elko Gary W. , Meyer Jens M.
Published: September 2012

We have developed a spherical microphone called the Eigenmike® microphone array that is capable of achieving up to third-order spherical harmonics decomposition of the sound field. One potential use of the spherical array is to investigate the spatial nature of sound fields in rooms. In this talk, we will show some measurement results where the processed data from an Eigenmike® array is used to compute various energy ratios between the direct, lateral, rear, and floor and ceiling directions. We will also show some other simple measures that might be useful in the spatial analysis and characterization of room acoustics.
A measurement technique achieving high spatial resolution for sound sources within a performance venue
Authors: Case Alex , Roginska Agnieszka , Anderson Jim
Published: September 2012

A proof of concept for gathering high spatial resolution sound radiation, from near field to far field, in 3 dimensions around an electric guitar amplifier is presented, with an eye and ear toward applying a similar technique to other essential sound sources. A high density microphone array is used to gather many thousands of impulse response in a hemi-anechoic space. The resulting data serves as a useful input to room models and auralizers, but finds added purpose as an educational tool in musical acoustics and sound recording.
A spatial encoding method for measured room impulse responses
Authors: Tervo Sakari , Pätynen Jukka , Lokki Tapio
Published: September 2012

The spatial information contained in measured room impulse responses can be used to explain some of the acoustical properties of performance spaces. This paper presents a spatial encoding method, which can extract accurate spatial information from impulse responses that are measured with at least four microphones in an open 3-D array. The method is based on decomposing a spatial room impulse response into a set of image-sources, i.e., every single sample in the impulse response is considered as an image source. Each of the image-sources is localized with an acoustic source localization method, which depends on the applied microphone array and the acoustic conditions. Due to the image-source presentation, the presented method can be applied to any compact array and used in conjunction with variety of current spatial loudspeaker reproduction systems to create convolution reverb-type spatial sound reproduction. The method allows static and interactive binaural reproduction via virtual loudspeaker arrays. The presentation includes demonstrations with a binaural reproduction system.
Acoustic tomography as a component of the Fram Strait observing system
Authors: Dushaw Brian D. , Sagen Hanne , Sandven Stein , Worcester Peter
Published: September 2012

The Fram Strait, a deep constriction between Svalbard and Greenland, is the primary location for the exchange of heat, mass and freshwater between the Arctic and Atlantic Oceans. With existing data and ocean modeling, current estimates of these exchanges, critical for understanding the Arctic Ocean climate, are inaccurate. To try to improve these estimates, during 2008-9 the DAMOCLES project deployed a test tomography path spanning the deep, ice-free part of the northward-flowing West Spitzbergen Current (WSC). Small-scale scintillations of sound speed due to eddies, fronts, and internal waves, are an important aspect of acoustic propagation of the region. Variability within Fram Strait, and the WSC in particular, is characterized by ubiquitous mesoscale eddies with 20-km scale. These eddies extend to depths of several hundred meters. Understanding the forward problem is essential for the inversion of acoustic data. The sound speed environment of Fram Strait generally prevents individual ray arrivals from being resolved in O(100-km) acoustic paths. An accurate inversion of these data for path-averaged sound speed (temperature) can be still be obtained, however. An objective mapping study, combining acoustic and existing data types, demonstrates that tomography will be a valuable and effective addition to the Fram Strait observing system.
Acoustics at the ALOHA Cabled Observatory
Authors: Howe Bruce M. , Duennebier Fred , Lukas Roger , Roth Ethan
Published: September 2012

Since 6 June 2011, the ALOHA Cabled Observatory (ACO) has been collecting ocean acoustic data, continuing an earlier data set covering February 2007 - October 2008. The ACO is at Station ALOHA 100 km north of Oahu, the field site of the Hawaii Ocean Time-series (HOT) program that has collected biological, physical, and chemical oceanographic data since 1988. At 4728 m water depth, it is the world’s deepest operating cabled observatory. ACO provides power and communications to user instrumentation. Among the instrumentation there are two hydrophones 1 m off the bottom separated by 1 m. One is an OAS Model E-2PD meant for low frequencies (0.014 Hz to 8 kHz). A second (uncalibrated) hydrophone is meant for higher frequencies. Current sampling rates for both hydrophones are 96 kHz; subsampled 24 kHz data are streamed to the Web in real-time. The system will be described and examples of acoustic events and signals presented, including local and distant earthquakes, marine mammals, surface waves, wind, rain, ships, sonars, and implosions. Plans for future acoustics research will be discussed. [Work supported by the National Science Foundation.]
On the region of feasibility of interference alignment for underwater acoustic communication
Authors: Pompili Dario
Published: September 2012

To enable underwater applications such as coastal and tactical surveillance, undersea explorations, and picture/video acquisition, there is a need to achieve high data-rate underwater acoustic communications, which translates into attaining high acoustic channel spectral efficiencies. Interference Alignment (IA) technique, which has recently been proposed for radio-frequency MIMO terrestrial communication systems, aims at improving the spectral efficiency by enabling nodes to transmit data simultaneously at a rate equal to half of the interference-free channel capacity. The core of IA lies in designing transmit precoding matrices for each transmitter such that all the interfering signals align at the receiver along a direction different from the desired signal. To decode, the receiver projects the received signal onto a decoding vector that is orthogonal to the data vector of interfering signal. While promising, there are challenges to be solved for the use of IA underwater, i.e., 1) imperfect acoustic channel knowledge, 2) high computational complexity, and 3) high communication delay. We study the feasibility of IA in underwater environment under these challenges; we also propose a distributed computational framework to parallelize the iterative IA algorithm and determine to what extent we can parallelize it among neighboring nodes under different channel coherence times.
Recent development and application of active acoustic techniques for studies of zooplankton ecology and implications for ocean observatories
Authors: Lawson Gareth L. , Lavery Andone C. , Wiebe Peter H. , Fincke Jonathan R. , Copley Nancy J.
Published: September 2012

High-frequency active acoustic techniques enjoy a long history in the study of zooplankton ecology and increasingly are being incorporated into ocean observing systems, addressing a pressing need for zooplankton-sampling capabilities. Discriminating among sources of scattering remains a key problem in ecological applications of active acoustics, however, especially when deploying on autonomous platforms, where independent sampling with nets or optics to verify acoustic observations is often not feasible. Here we consider the ecological insights that can be afforded by active acoustic methods and implications to the design of ocean observing systems by reporting on (1) a series of recent field studies of krill ecology employing both a traditional multi-frequency system (43, 120, 200, 420 kHz) and a recently-developed broadband system (30-600 kHz) designed to provide enhanced capabilities for discrimination of scattering sources, and (2) test deployments on autonomous platforms of a low-power active acoustic system capable of broadband or narrowband transmission. Comparisons to concurrent sampling with a depth-stratified net system, when available, allow an assessment of the abilities of these acoustic systems for remotely discriminating among sources of scattering and for estimating the abundance and size of animals.
Passive acoustics monitoring as part of integrated ocean observing systems
Authors: Luczkovich Joseph J. , Sprague Mark W. , Krahforst Cecilia S. , Corbett D. Reide , Walsh John P.
Published: September 2012

Passive acoustic monitoring can be a useful tool to include on Ocean Observing Systems. As an example, we describe the monitoring the acoustic environment in the coastal waters of North Carolina (USA) using an instrumented platform. The ECU Itpod (instrumented tripod) has been deployed in several locations in Pamlico Sound and river estuaries since 2006 to study fishes in the Family Sciaenidae (drums and croakers). We will present data recorded with hydrophones deployed on the Itpod with remote data loggers, acoustic Doppler current profilers, turbidity meters and water quality instruments. We have used passive acoustic recordings to study the correlations of fish sounds and environmental parameters (temperature, salinity, turbidity, dissolved oxygen, wave action, river discharge, tropical storms). The long-term data suggest that spring temperature increases are associated with increased activity of acoustically mediated courtship and spawning behavior of sciaenid fishes; these sounds decline in the fall as water temperature declines. In addition, we have observed acoustic interactions between marine mammal predators and their fish prey and the effects of noise from tugs and small boats on fish sound production. Itpods must be recovered periodically to recover data and replenish batteries; solar-powered platforms and automated fish detection algorithms are under development.
A low cost, open source autonomous passive acoustic recording unit for recording marine animals
Authors: Valtierra Robert D. , VanParijs Sofie M. , Holt R. G. , Mace Connor , Silver Kara , Bernard Chris
Published: September 2012

An autonomous passive acoustic recording unit (ARU) was developed through a collaboration between the Boston University Department of Mechanical Engineering and the NOAA Northeast Fisheries Science Center. The ARU consists of two main sections, an electronic data logger and a mechanical pressure case and release. The datalogger makes use of widely adopted commercial hardware such as SD card memory and USB connectivity. In addition, WAV file formats and open-source compiler software allow flexibility and programmability at minimal expense. The pressure case was designed for shallow water (100 m) applications with few machined parts and several “off the shelf” parts. The overall system can be constructed at a minimal cost and has been successfully tested during both laboratory and at-sea trials.
Tracking and source level estimation of multiple sperm whales in the Gulf of Alaska using a two-element vertical array
Authors: Mathias Delphine , Thode Aaron M. , Straley Jan , Andrews Russel D.
Published: September 2012

Between 15-17 August 2010 a two-element vertical array (VA) was deployed in 1200 m deep water off the continental slope of Southeast Alaska. The array was attached to a longline fishing buoyline at 300 m depth, close to the sound-speed minimum of the deep-water profile. The line also attracted seven depredating sperm whales to the area, each generating impulsive `clicks' that arrived on the VA via multiple ray paths. The propagation model BELLHOP was used to model relative arrival times and vertical elevation angles of click ray paths as a function of depth and range from the VA. The resulting tracking system yielded range-depth tracks of multiple animals out to at least 35 km range. These locations, along with the transmission loss estimates of the model, permitted the sound source levels to be recovered. Here we present the consistency of source levels from individuals over time, the degree of source level variation between individuals, and possible correlations between inter-click interval and source level. This analysis suggests how a relatively simple ocean observing acoustic system could localize bioacoustic signals over large ranges, given the appropriate deployment configuration.
Acoustic thermometry as a component of the global ocean observing system
Authors: Dushaw Brian D.
Published: September 2012

Acoustic data acquired during the 1995-2006 Acoustic Thermometry of Ocean Climate (ATOC) program were used to test the accuracy of ocean state estimates of the North Pacific obtained by various means: simple forward integration of a model, objective analysis of hydrographic and altimeter data, and data assimilation using general circulation models. The comparisons of computed and measured time series stringently tested the accuracy of the state estimates. The differences were substantial, indicating that acoustic thermometry provides unique information about the large-scale temperature. On some acoustic paths, changes in temperature occurring over time scales of weeks with magnitudes comparable to the seasonal cycle were observed. Acoustic thermometry offers valuable constraints on the large-scale thermal variability for the ocean observing system. Acoustic tomography was accepted as part of the Ocean Observing System during the OceanObs'99 and '09 international workshops. Sources and receivers of acoustic thermometry can serve multiple purposes. Hydrophone arrays are used to study a wide range of human, biological, and geological activity. Acoustic sources can transmit signals that can be used to track drifting instrumentation. A modest number of active and passive acoustic instruments deployed worldwide can form a general purpose global acoustic observing network.
Full-wave nonlinear ultrasound simulation on distributed clusters using the k-space pseudospectral method
Authors: Treeby Bradley E. , Jaros Jiri , Cox Ben T. , Rendell Alistair P.
Published: September 2012

Performing realistic simulations of the propagation of nonlinear ultrasound waves through biological tissue is a computationally difficult task. This is because the domain size of interest is often very large compared to the wavelengths of the high-frequency harmonics generated as the ultrasound waves progress. Recently, the k-space pseudospectral method has been applied to this problem to reduce the number of grid points required per wavelength compared to finite difference methods. However, the global nature of the spectral gradient calculations used in this method introduces new challenges for tackling large-scale problems. Here, we discuss three important issues for pseudospectral methods in the context of distributed computing. (1) Decomposing the domain to allow distribution across multiple nodes while still retaining the global accuracy of the spectral gradient calculations. (2) Using non-uniform grids to allow grid points to be clustered around highly nonlinear regions. (3) Avoiding aliasing errors due to modeling nonlinear wave propagation on a fixed grid. For each issue, solutions that retain the efficiency advantages of the pseudospectral method are discussed. We then present recent results of large-scale 3D nonlinear ultrasound simulations in heterogeneous and absorbing media running on both shared memory computers and distributed computer clusters.
Numerical simulations of three-dimensional nonlinear acoustical waves: Application to the modeling of helicoïdal beams
Authors: Marchiano Régis , Thomas Jean-Louis , Baresch Diego
Published: September 2012

A numerical method for the simulation of three-dimensional nonlinear acoustical wave propagation through a homogeneous or weakly heterogeneous medium is presented. This method is based on the resolution a nonlinear wave equation taking into account diffraction, nonlinearities and weak heterogeneities exact up to second order. It is numerically solved in a one-way manner by using a classical splitting method in three steps: angular spectrum method for diffraction, implicit finite differences method for heterogeneities, and semi-analytical Burgers-Hayes method for nonlinearities. Simulations of propagation of nonlinear helicoïdal beams will illustrate the capacities of the method. This kind of acoustical beams featuring radial, azimuthal and axial variations of the field is intrinsically three-dimensional. Furthermore, they have properties of potential interest in biomedical acoustics either for imaging purposes (dynamics of the so-called topological charge) or for therapy purposes (generation of helical shock front or acoustical tweezers with radiation force).
Medical application of nonlinear wave vector frequency domain modeling
Authors: Clement Gregory T. , Jing Yun
Published: September 2012

While the nonlinear properties of tissues have been well documented, the computational demands required to solve nonlinear partial differential equations have generally restricted the dimensionality of numeric studies. These restrictions have been significantly reduced over time, thanks to increased memory and processing availability. Combined with more efficient computational approaches, PC-based three-dimensional modeling of nonlinear fields in tissues is now becoming feasible. Both diagnostic and therapeutic ultrasound could benefit from such accessible modeling, providing a tool for studying customized energy deposition, harmonic signal buildup, parametric methods, transducer characterization, thermometry methods, etc. We will present one such approach, which calculates diffraction through the solution to the homogenous frequency-domain Westervelt equation, while nonlinearity is calculated by the particular solution through a Green's function. The validity and efficiency of the method will be demonstrated by comparison with other well-established methods. This approach also permits backward projection of waves from an initial measurement plane toward the source, allowing a single plane to characterize an entire field, including nonlinear induction of both harmonic and sub-harmonic wave components. This ability will be shown using experimental measurements acquired with a focused source designed for HIFU.
Modeling acousto-optic sensing of high-intensity focused ultrasound lesion formation
Authors: Adams Matthew T. , Giraud David S. , Cleveland Robin O. , Roy Ronald A.
Published: September 2012

Real-time acousto-optic (AO) sensing has been shown to non-invasively detect changes in tissue optical properties, a direct indicator of thermal damage, during high-intensity focused ultrasound (HIFU) therapy. In this work, a comprehensive model is developed to describe the AO sensing of lesion formation during HIFU therapy. The angular spectrum method is used to model ultrasound propagation, and the temperature field due to the absorption of ultrasound is modeled using a finite-difference time-domain (FDTD) solution to the Pennes bioheat equation. Thermal damage dependent optical properties are calculated based on a probabilistic and calibrated thermal dose model. To simulate light propagation inside of insonified and optically heterogeneous tissue, an open-source graphics processing unit (GPU) accelerated Monte Carlo algorithm is used. The Monte Carlo algorithm is modified to account for light-sound interactions, using input from the angular spectrum method, and to account for AO signal detection. Results will show how wavelength and illumination/detection configurations affect the detectability of HIFU lesions using AO sensing.
Modeling translation of a pulsating spherical bubble between viscoelastic layers
Authors: Tengelsen Daniel R. , Hay Todd A. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: September 2012

A model was developed previously that enables calculation of the translational force exerted on a pulsating bubble between parallel viscoelastic layers [Hay et al., J. Acoust. Soc. Am. 128, 2441 (2010)]. Here the translational motion of the bubble is taken into account. Force on the bubble is calculated with a Green’s function for the reverberant acoustic field in the channel. The Green’s function takes into account not only elastic waves in the channel walls but also viscous boundary layers at the interfaces with the liquid. The dynamical response of the bubble is modeled by an equation of Rayleigh-Plesset form for pulsation, coupled to a momentum equation for translation. The dynamical equations are coupled to the Green’s function providing the reverberant pressure field and its gradient acting on the bubble. Calculation of the time-dependent Green’s function requires integration over both wavenumber and frequency space at each location along the trajectory of the bubble. Different numerical implementations were considered based on accuracy and efficiency. Simulations will be presented for several combinations of bubble radius, standoff distance, and viscous boundary layer thickness. [Work supported by the ARL:UT McKinney Fellowship in Acoustics and NIH DK070618.]
Motional current velocity control of piezoelectric loads
Authors: Randall Robert C.
Published: September 2012

It is well known that acoustic interactions affect the transmit radiation pattern of a SONAR array, particularly when the element spacing is small relative to the acoustic wavelength. A negative feedback system with a velocity sense signal fed back to the power amplifier is one method of mitigating the array interactions, and has significant advantages for wideband use compared to either open loop compensation or passive electrical tuning. A velocity control loop flattens the transducer’s frequency response, and also reduces the effects of the array interactions proportional to the loop gain. The velocity feedback signal for piezoelectric loads may be obtained by the motional current method, which is equivalent to using an ideal massless accelerometer if the transducer’s electrical branch admittance is estimated correctly. The transducer’s coupling coefficient, mechanical Q, and a priori estimate of the blocked capacitance fundamentally limits both the maximum stable loop gain, and the output velocity gain and phase tracking relative to the amplifier’s input voltage. The array equations governing the acoustical outputs are presented, both with and without motional current velocity control.
A wideband moving coil electrodynamic transducer system for autonomous underwater vehicle-based geoacoustic inversion
Authors: Massa Donald P. , Arvelo Juan I.
Published: September 2012

A small expendable wideband low-frequency sound source that will be deployed on the seafloor is being developed to be used for geoacoustic inversion surveys in conjunction with a terrain-hugging AUV. This low-cost deployable source contains a transducer that produces a relatively flat transmit response over the broad frequency band of 100 to 4000 Hz. In operation, a seafloor interface wave will be excited and exploited for geoacoustic inversion by the deployed sound source and a receiving array on the bottom-hugging AUV. A feasibility study is also being performed that includes physics-based sonar simulations to infer the performance of geoacoustic inversion in a number of AUV scenarios and environmental conditions. Based on this study, design trade-offs will be determined to finalize key factors of the transducer, such as its physical size, weight, and production cost. Battery technology is also being developed to optimize the source level, the duty cycle, and the operating life of the signals that will be transmitted during data collection. This effort is being supported by ONR.
Array synthesis and wide band system
Authors: Huang Dehua
Published: September 2012

Acoustic arrays play important role as the key devices in wide band system designs. The Laguerre polynomials are successfully applied to the array synthesis first time. Conventional uniform array is the simplest design, because each element is excited at the same weight, which leads to high side lobe levels, artifacts and noise to advanced systems. Dolph utilized the first kind Chebyshev polynomials to synthesize the array beam pattern for side lobe control. However, it comes with the equal levels of the side lobes, due to the mathematical nature of the first kind Chebyshev polynomials. Taylor introduced a modified version Dolph-Chebyshev synthesis technique, which displayed tapered down side lobe levels in the region away from the main lobe. The key characteristics from the sample numerically simulated arrays by the Laguerre polynomials synthesis, i. e. radiation patterns, half-power beam width, directivity and the beam efficiency are compared with those from the synthesis of the Dolph-Chebyshev of the first kind or second kind, Taylor shading, Legendre and Hermite polynomials techniques. Work supported by the U.S. Navy.
Collaborating to improve science teaching and learning through the ComPADRE digital library I
Authors: Mason Bruce , Barbato Lyle
Published: September 2012

Most educators have found that improving their classes is best done as a collaborative process, by sharing best practices and resources with others. The ComPADRE digital library has been supporting these collaborations for the past decade through a vetted, online database of teaching and learning materials, personalization services, and tools for groups to interact. This talk will explore some examples of the resources available through the ComPADRE database that can be used to engage students in learning and can help instructors improve the outcomes of their courses. It will cover the organization of materials and how ComPADRE members can meet their personal needs. The talk will also explore examples of ComPADRE collections built by and for communities of teachers interested in specific topics or courses. Of course, examples of fun and engaging learning materials will also be demonstrated. ComPADRE is a collaboration of the American Association of Physics Teachers, the American Institute of Physics, the American Physical Society, and the Society of Physics Students and is part of the National STEM Digital Library. It is supported, in part, by funding of the National Science Foundation.
Teaching musical acoustics with clickers
Authors: Hartmann William
Published: September 2012

Musical acoustics is a well-proved avenue for teaching scientific concepts to students whose fields of study and interests are far removed from any science. In recent years the Michigan State course in musical acoustics has benefited greatly from using clickers. Frequent clicker questions (1 point for any answer; 2 points for the correct answer) promote attendance and help maintain a lively, interactive classroom environment, even for a large lecture class. Nobody sleeps when clicker points are on the line. Students are encouraged to discuss responses to clicker questions among themselves before answering, and the response protocol allows students to change their responses at any time before the polling is closed. Musical acoustics lectures include many demonstrations that can be presented as experiments requiring students to predict the result in advance using their clickers. “No-count” or “all-good” clicker questions can be used to determine student responses to perceptual experiments, and the feedback from the scoring algorithm gives the answer and the inevitable variability. Most important, responses to clicker questions give an instructor instant feedback about whether new lecture material has been understood. To use clickers in this way requires flexible instruction and spontaneous generation of new clicker questions.
Providing interactive engagement in introductory acoustics through design-intensive laboratories
Authors: Morrison Andrew
Published: September 2012

More than three decades worth of education research has shown with overwhelming evidence that the best way for students to learn is to be actively engaged in the classroom rather than passively taking in material delivered from an instructor. Although the reform of introductory classes has been widely adopted by many instructors, the implementation of reformed introductory laboratory curricula has not been as widely adopted. In our introductory acoustics course, students complete design-intensive labs where much of the instruction has been stripped away. The emphasis on student-driven experiment design and analysis is intended to provide a more scientifically authentic experience for students. The course is taught using an integrated lecture and laboratory approach. An overview of the laboratory framework and example laboratory activities used in our introductory acoustics class will be presented.
Techniques for teaching building acoustics and noise control to university architecture students
Authors: Coffeen Robert C.
Published: September 2012

Architects are visual people. And, we cannot see sound in an architectural venue. Perhaps this has something to do with their historically poor record in dealing with acoustic and noise control issues in building spaces. Experience in teaching architecture students indicates useful teaching techniques include visits to venues with both suitable and unsuitable acoustic conditions, using modeling and auralization so that students can hear simulations of acoustical conditions produced by various interior surface shapes and architectural materials, relating their actual listening experiences in venues of various types to interior surface shapes and finish materials, and discussing the acoustical characteristics of interior materials so that a visual inspection of a space can lead to a general determination of the room acoustic conditions to be anticipated. Also discussed will be techniques for teaching architecture students the basics of architectural noise control and the basics of mechanical system noise control.
Acoustic tweets and blogs: Using social media in an undergraduate acoustics course
Authors: Wang Lily M.
Published: September 2012

Each fall, the author teaches an undergraduate architectural acoustics course to around 40 third-year architectural engineering students at the University of Nebraska. Beginning in 2011, a social media component was introduced to explore the use of this technology and how it may supplement the students’ learning experience. Students were given an opportunity to receive extra credit by using twitter and/or blogging about course material using a set hashtag (#AE3300) or through the course website. Results were positive, and the author will discuss pros and cons that she has experienced in adding this social media component. Suggestions for future implementations and examples of student participation will be presented.
Use of pre-class quizzes to promote active learning in acoustics
Authors: Gee Kent L. , Neilsen Tracianne B.
Published: September 2012

Classroom instruction can be inefficient or ineffective when students do not come to class prepared. One strategy to engage students prior to class is the use of pre-class quizzes. One pedagogical method developed for introductory courses by physics education researchers is pre-class “just-in-time-teaching” quizzes. As a variation on that idea, pre-class learning activities have been used with great success in the general education acoustics course at Brigham Young University (BYU). However, such methods are not often applied at the advanced undergraduate and graduate levels. This paper reviews some of the findings from the introductory course efforts and then describes the implementation of pre-class quizzes for two advanced acoustics courses at BYU. Two lessons learned thus far are 1) the questions, which have a free-response format, must be carefully constructed so that the instructor can gauge student understanding, and 2) when successfully implemented, the quizzes can provide an effective framework for a class discussion of a topic, rather than a lecture with little to no participation.
Active-learning techniques in an introductory acoustics class
Authors: Neilsen Tracianne B. , Gee Kent L.
Published: September 2012

The goal of active-learning techniques is to encourage the students to become involved with the material and take ownership for their learning, which fosters long-term knowledge and enjoyment of the subject. In this era of student-based learning outcomes, an active-learning approach is important because it focuses on what the students are doing to facilitate learning instead of what the instructor is trying to teach. To benefit most from class time, the students need to have the opportunity to actively engage with the material beforehand. If meaningful pre-class activities are required, it is easier to interact with the students during class. Some key methods for encouraging active learning during class include incorporating their pre-class experiences, conducting discussions, encouraging student participation, and evaluating student understanding with a response system, such as i-clickers. After the class time, students need apply what they have learned in answering additional questions on homework assignments and in hands-on laboratory experiences. Lessons learned after several years’ worth of step-by-step efforts to approach these goals in an introductory acoustics class, which serves a wide range of majors as a general science elective, are presented.
Problem solving assessment
Authors: Adams Wendy K.
Published: September 2012

Although educators and employers highly value problem solving and have put extensive effort into understanding successful problem solving, there is currently no efficient way to evaluate it. Science educators regularly make use of concept inventories and perceptions surveys (aka: attitudes and beliefs) to evaluate instruction. However, these only touch on a fraction of what is learned in a course. Students apply a range of processes, expectations and bits of knowledge when solving a physics problem and some of these are impacted by the course. The question is how can we identify what these processes, expectations and knowledge are, how can we teach them and then how can we measure them? While developing the CAPS (Colorado Assessment of Problem Solving), I identified 44 processes, expectations and bits of knowledge used to solve an in depth real world problem. In this presentation CAPS and some of what was learned during the development will be presented.
Approaching environmental resources through soundscape
Authors: Schulte-Fortkamp Brigitte
Published: September 2012

The Soundscape concept is introduced as a scope to rethink the evaluation of “noise” and its effects and to focus on a diverse field of experts and expertise in order to fulfill the requirements for a “good environment” or a “sensitive environment” with respect to quality of life. Moreover, Soundscape is defined as an environment of sound with emphasis on the way it is perceived and understood by the individual, or by a society. Therefore it is suggested to explore noise in its complexity and its ambivalence and its approach towards sound to consider the conditions and purposes of its production, perception, and evaluation, to understand evaluation of noise/ sound as a holistic approach. Qualitative methods referring to a heterogeneous ‘field of research’ and among them are different forms of observation, interviewing techniques and the collection of documents or archival data as well as binaural measurements will be presented and proven regarding their effects of explanations. The intention of scientific research here is to learn about the meaning of the noise with respect to people’s living situation and to implement the adequate procedure to open the “black box” of people’s mind regarding their needs for a supportive environment.
Relationship between environmental noise, sound quality, soundscape
Authors: Genuit Klaus , Fiebig André , Schulte-Fortkamp Brigitte
Published: September 2012

The term “Environmental Noise” is well known for many years. Its characteristic is often described by parameters like A-weighted SPL, Lden, Lday, Levening, Lnight. These parameters can be measured and calculated. In the field of “Sound Quality” psychoacoustic parameters are additionally used like loudness, sharpness, roughness and others, which can be measured but not calculated for a complex sound field. On an international level a standard is available only for the loudness of stationary sounds so far. The “relatively” young term “soundscape” will be standardized in ISO 12913-1. Moreover, as it considers human perception including cognitive aspects, context and interaction it goes beyond physics and psychoacoustics. It involves a concept, where environmental noise is not reduced to an averaged quantity evoking only unpleasantness feelings estimated by statistical probabilities, but understanding noise as a valuable resource, which can be purposefully utilized. In spite of recent progresses in the standardization process lots of misinterpretations occur in practical use, where the terms are heavily mixed up. Environmental noise and soundscape are no synonyms, for example low noise level does not directly mean a good sound quality. The paper will clarify options and limitation of both terms.
Soundscape and sound quality—Similar and powerful design techniques
Authors: Brooks Bennett M.
Published: September 2012

Two powerful analysis techniques available to acoustical researchers and designers include the sound quality method and the very similar soundscape method. In each of these techniques physical acoustical measurements are combined with in-depth interviews and opinion juries to determine the cause and effect relationship that a particular sound, or set of sounds, has on a population. The sound quality technique has been in use for many years, and focuses on product development. An example is the sound of an automobile door closing - is the car door closing sound perceived as “solid and expensive” or “cheap and tinny”. Another example is a vacuum cleaner - does it sound "powerful and effective" or “weak and ineffective”? The soundscape technique focuses on environmental sound, often in public spaces like a park or in a residential neighborhood. For example, is a certain transportation vehicle sound or outdoor entertainment facility sound acceptable or unacceptable to the wider community? This paper will explore the similarities between these two related fields and the opportunities they offer to sound designers.
The sound-absorbing city—New ideas for living environments around airports
Authors: Bauer Juergen
Published: September 2012

Great efforts and progress have been made in terms of noise protection measures in both urban, suburban and rural environments. Local or regional urban planning guidelines and anti-noise-manuals provide experienced and practical advice to reduce noise, in order to provide a better quality of life. Most of the anticipated solutions such as noise-protection-walls, fences, planted mounds etc. will address issues caused by land traffic. However, due to their nature, they fail to respond to "airborne" noise immission. In addition, there is a common public misconception that sound should be interpreted as noise ie. as a waste to get rid of, instead of critically identifying sound and sound clusters as a potential and as a resource to be integrated. The concept of the sound-absorbing city applies the same principles of sound reflection and sound absorption, as applied to an architectural space, in an urban space. It also investigates the possibility of combining unwanted sound, such as air traffic noise with wanted sound, such as nature and community sound. The paper discusses the concept of the sound-absorbing city, its potentials and its apparent limits, with regard to new settlements and existing agglomerations around airports.
I hear what you mean—Source intensity versus receiver level
Authors: Case Alex
Published: September 2012

A receiver’s assessment of the quality of any single element of a soundscape is not limited to the objective values of sound attributes at the receiver location, but includes an intuitive or instinctive compensation for the source-to-receiver path. Borrowing from the time-proven connection between performance intensity versus presented level in sound recordings, emotion and meaning are found to include what a listener infers about the local environment and context at the sound source, discounting whatever may have happened on its way to the listener.
Soundwalks in urban areas—Triangulation of perceptive and acoustical data
Authors: Voigt Kay S. , Schulte-Fortkamp Brigitte
Published: September 2012

Current work takes a comparative view on the analysis of several soundwalks in urban areas, investigating the benefit of additional effort in enhancing the attendees' description-level for data triangulation. Soundwalk is a tool in the soundscape approach for an all-embracing analysis of the unique sonic environment. The triangulation of data has to combine acoustical measurements of the same procedures and perceptive appraisals differing in its quality of description. The focus of each research varies from perception of places to questions of the overall feeling of safety at the different locations. Local, acoustical and safety experts are involved. The qualitative analysis considers several variables like profession of soundwalkers, knowledge about places, kind of places, chosen or given locations, and the used native language of questioning. Different levels of description narrated by the participators will be identified, as well as its possible emphasis by discourse on attendees' scaled ratings and written notes. This analysis progress contributes to an appropriate assignment of subjective descriptions to values of psychoacoustical parameters and the elucidation of predominant aspects in the soundscape. Furthermore the soundwalk's contrasting capacity with regards to the content of previous interviews detected multiple layers on the issue of safety in municipal locations.
Sound and noise in urban parks
Authors: Carvalho Antonio P. , Dias Ricardo C.
Published: September 2012

The main goal of this work is to study the soundscape of urban gardens and parks using a sample of ten sites in Porto, Portugal to characterize their noise levels through the acoustic characterization of the park's exterior and interior noise levels (LAeq, LA10, LA50 and LA90) and by a socio-acoustic survey to the visitors to check their perception of acoustic quality. The measurements showed gardens/parks with interior noise levels from 47 to 61 dBA (with maximum exterior noise levels up to 67 dBA). The difference between exterior and interior LAeq was between 3 and 19 dBA. The gardens with lower noise levels are the larger and out of downtown. An “acoustic” classification for gardens/urban parks is proposed regarding their noise “isolation” capacity and acoustic ambience. Measurements done in 1990 allow for the comparison of the evolution in the last 21 years. The socio-acoustic survey concludes that Porto’s city parks are visited mostly by an elderly male population that regards these places as sites of gathering and to practice some physical activity rather than as an acoustic retreat. The population seems accustomed to the dominant noise, classifying these spaces as pleasant and quiet, even when noise is over acceptable limits.
Ultrasound therapy delivery and monitoring through intact skull
Authors: Hynynen Kullervo , Huang Yuexi , O'Reilly Meaghan , Jones Ryan , Pajek Dan , Pulkkinen Aki
Published: September 2012

Magnetic Resonance imaging guided and monitored focused ultrasound is now tested for deep focal thermal ablation of brain tissue in clinical setting. The major barrier for this treatment is the propagation of ultrasound through an intact skull that strongly attenuates and scatters the ultrasound wave. The distortion can be corrected by using CT-derived bone density information and computer simulations to derive phase and amplitude information such that the driving signals can be adjusted to reduce the distortions. In this paper the current results on ultrasound propagation through skull will be discussed and the clinical applications of noninvasive ultrasound treatments will be reviewed. The advance in online acoustic monitoring of cavitation based treatments methods will also be shown