SwePub - search: L773:0001 4966

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1.	Ahrens, Jens, 1978, et al. (author) Perceptual evaluation of headphone auralization of rooms captured with spherical microphone arrays with respect to spaciousness and timbre 2019 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 145:4, s. 2783-2794 Journal article (peer-reviewed)abstract A listening experiment is presented in which subjects rated the perceived differences in terms of spaciousness and timbre between a headphone-based headtracked dummy head auralization of a sound source in different rooms and a headphone-based headtracked auralization of a spherical microphone array recording of the same scenario. The underlying auralizations were based on mea- sured impulse responses to assure equal conditions. Rigid-sphere arrays with different amounts of microphones ranging from 50 to up to 1202 were emulated through sequential measurements, and spherical harmonics orders of up to 12 were tested. The results show that the array auralizations are partially indistinguishable from the direct dummy head auralization at a spherical harmonics order of 8 or higher if the virtual sound source is located at a lateral position. No significant reduction of the perceived differences with increasing order is observed for frontal virtual sound sources. In this case, small differences with respect to both spaciousness and timbre persist. The evaluation of lowpass-filtered stimuli shows that the perceived differences occur exclusively at higher frequen- cies and can therefore be attributed to spatial aliasing. The room had only a minor effect on the results.
2.	Ahrens, Jens, 1978, et al. (author) Spherical harmonic decomposition of a sound field based on observations along the equator of a rigid spherical scatterer 2021 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 150:2, s. 805-815 Journal article (peer-reviewed)abstract We present a method for computing a spherical harmonic representation of a sound field based on observations of the sound pressure along the equator of a rigid spherical scatterer. Our proposed solution assumes that the captured sound field is height invariant so that it can be represented by a two-dimensional (2D) plane wave decomposition (PWD). The 2D PWD is embedded in a three-dimensional representation of the sound field, which allows for perfectly undoing the effect of the spherical scattering object. If the assumption of height invariance is fulfilled, then the proposed solution is at least as accurate as a conventional spherical microphone array of the same spherical harmonic order, which requires a multiple of the number of sensors. Our targeted application is binaural rendering of the captured sound field. We demonstrate by analyzing the binaural output signals that violations of the assumptions that the solution is based on—particularly height invariance and consequently also horizontal propagation—lead to errors of moderate magnitude.
3.	Akita, Kimi, et al. (author) Iconicity mediates semantic networks of sound symbolism 2024 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 155:4, s. 2687-2697 Journal article (peer-reviewed)abstract One speech sound can be associated with multiple meanings through iconicity, indexicality, and/or systematicity. It was not until recently that this “pluripotentiality” of sound symbolism attracted serious attention, and it remains uninvestigated how pluripotentiality may arise. In the current study, Japanese, Korean, Mandarin, and English speakers rated unfamiliar jewel names on three semantic scales: size, brightness, and hardness. The results showed language-specific and cross-linguistically shared pluripotential sound symbolism. Japanese speakers associated voiced stops with large and dark jewels, whereas Mandarin speakers associated [i] with small and bright jewels. Japanese, Mandarin, and English speakers also associated lip rounding with darkness and softness. These sound-symbolic meanings are unlikely to be obtained through metaphorical or metonymical extension, nor are they reported to colexify. Notably, in a purely semantic network without the mediation of lip rounding, softness can instead be associated with brightness, as illustrated by synesthetic metaphors such as yawaraka-na hizashi /jawaɾakanaçizaɕi/ “a gentle (lit. soft) sunshine” in Japanese. These findings suggest that the semantic networks of sound symbolism may not coincide with those of metaphor or metonymy. The current study summarizes the findings in the form of (phono)semantic maps to facilitate cross-linguistic comparisons of pluripotential sound symbolism.
4.	Alku, Paavo, et al. (author) An amplitude quotient based method to analyze changes in the shape of the glottal pulse in the regulation of vocal intensity 2006 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 120:2, s. 1052-1062 Journal article (peer-reviewed)abstract This study presents an approach to visualizing intensity regulation in speech. The method expresses a voice sample in a two-dimensional space using amplitude-domain values extracted from the glottal flow estimated by inverse filtering. The two-dimensional presentation is obtained by expressing a time-domainmeasure of the glottal pulse, the amplitude quotient (AQ), as a function of the negative peak amplitude of the flow derivative (d(peak)). The regulation of vocal intensity was analyzed with the proposed method from voices varying from extremely soft to very loud with a SPL range of approximately 55 dB. When vocal intensity was increased, the speech samples first showed a rapidly decreasing trend as expressed on the proposed AQ-d(peak) graph. When intensity was further raised, the location of the samples converged toward a horizontal line, the asymptote of a hypothetical hyperbola. This behavior of the AQ-d(peak) graph indicates that the intensity regulation strategy changes from laryngeal to respiratory mechanisms and the method chosen makes it possible to quantify how control mechanisms underlying the regulation of vocal intensity change gradually between the two means. The proposed presentation constitutes an easy-to-implement method to visualize the function of voice production in intensity regulation because the only information needed is the glottal flow wave form estimated by inverse filtering the acoustic speech pressure signal.
5.	Alvarsson, Jesper J., et al. (author) Aircraft noise and speech intelligibility in an outdoor living space 2014 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 135:6, s. 3455-3462 Journal article (peer-reviewed)abstract Studies of effects on speech intelligibility from aircraft noise in outdoor places are currently lacking. To explore these effects, first-order ambisonic recordings of aircraft noise were reproduced outdoors in a pergola. The average background level was 47 dB L-Aeq. Lists of phonetically balanced words (L-ASmax,L- word = 54 dB) were reproduced simultaneously with aircraft passage noise (L-ASmax,L- noise = 72-84 dB). Twenty individually tested listeners wrote down each presented word while seated in the pergola. The main results were (i) aircraft noise negatively affects speech intelligibility at sound pressure levels that exceed those of the speech sound (signal-to-noise ratio, S/N < 0), and (ii) the simple A-weighted S/N ratio was nearly as good an indicator of speech intelligibility as were two more advanced models, the Speech Intelligibility Index and Glasberg and Moore's [J. Audio Eng. Soc. 53, 906-918 (2005)] partial loudness model. This suggests that any of these indicators is applicable for predicting effects of aircraft noise on speech intelligibility outdoors.
6.	Amundin, Mats, 1947-, et al. (author) An echolocation visualization and interface system for dolphin research 2008 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 123:2, s. 1188-1194 Journal article (peer-reviewed)abstract The present study describes the development and testing of a tool for dolphin research. This tool was able to visualize the dolphin echolocation signals as well as function as an acoustically operated "touch screen." The system consisted of a matrix of hydrophones attached to a semitransparent screen, which was lowered in front of an underwater acrylic panel in a dolphin pool. When a dolphin aimed its sonar beam at the screen, the hydrophones measured the received sound pressure levels. These hydrophone signals were then transferred to a computer where they were translated into a video image that corresponds to the dynamic sound pressure variations in the sonar beam and the location of the beam axis. There was a continuous projection of the image back onto the hydrophone matrix screen, giving the dolphin an immediate visual feedback to its sonar output. The system offers a whole new experimental methodology in dolphin research and since it is software-based, many different kinds of scientific questions can be addressed. The results were promising and motivate further development of the system and studies of sonar and cognitive abilities of dolphins. © 2008 Acoustical Society of America.
7.	Andersson, Carl, 1992 (author) Acoustic levitation of multi-wavelength spherical bodies using transducer arrays of non-specialized geometries 2022 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 151:5, s. 2999-3006 Journal article (peer-reviewed)abstract Recently, acoustic levitation of a wavelength-sized spherical object using a general-purpose ultrasonic transducer array was demonstrated. In this article, the possibility of extending the capabilities of such arrays to levitate multi-wavelength-sized objects is explored. The driving signals for the elements in the array are determined via numerical optimization of a physics-based cost function that includes components for trap stabilization. The cost function is balanced with an improved approach, mimicking dynamical de-weighting of the included components to avoid over-optimization of each individual component. Sound fields are designed and analyzed for levitation of objects with diameters up to 50 mm for various general-purpose simulated array configurations. For a 16 x 16 element transducer array, simulations predict levitation of spheres with diameters up to 20 mm (2.3 wavelengths), which is verified experimentally.
8.	Arehart, Kathryn, et al. (author) Relationship between distortion and working memory for digital noise-reduction processing in hearing aids 2014 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 133:5 Journal article (peer-reviewed)abstract Several recent studies have shown a relationship between working memory and the ability of older adults to benefit from specific advanced signal processing algorithms in hearing aids. In this study, we quantify tradeoffs between benefit due to noise reduction and the perceptual costs associated with distortion caused by the noise reduction algorithm. We also investigate the relationship between these tradeoffs and working memory abilities. Speech intelligibility, speech quality, and perceived listening effort were measured in a cohort of elderly adults with hearing loss. Test materials were low-context sentences presented in fluctuating noise conditions at several signal-to-noise ratios. Speech stimuli were processed with a binary mask noise-reduction strategy. The amount of distortion produced by the noise reduction algorithm was parametrically varied by manipulating two binary mask parameters, error rate, and attenuation rate. Working memory was assessed with a reading span test. Results will be discussed in terms of the extent to which intelligibility, quality, and effort ratings are explained by the amount of distortion and/or noise and by working memory ability. [Funded by NIH, Oticon, and GN ReSound.].
9.	Arnela, Marc, et al. (author) Influence of lips on the production of vowels based on finite element simulations and experiments 2016 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 139:5, s. 2852-2859 Journal article (peer-reviewed)abstract Three-dimensional (3-D) numerical approaches for voice production are currently being investigated and developed. Radiation losses produced when sound waves emanate from the mouth aperture are one of the key aspects to be modeled. When doing so, the lips are usually removed from the vocal tract geometry in order to impose a radiation impedance on a closed cross-section, which speeds up the numerical simulations compared to free-field radiation solutions. However, lips may play a significant role. In this work, the lips' effects on vowel sounds are investigated by using 3-D vocal tract geometries generated from magnetic resonance imaging. To this aim, two configurations for the vocal tract exit are considered: with lips and without lips. The acoustic behavior of each is analyzed and compared by means of time-domain finite element simulations that allow free-field wave propagation and experiments performed using 3-D-printed mechanical replicas. The results show that the lips should be included in order to correctly model vocal tract acoustics not only at high frequencies, as commonly accepted, but also in the low frequency range below 4 kHz, where plane wave propagation occurs.
10.	Arnela, Marc, et al. (author) Influence of vocal tract geometry simplifications on the numerical simulation of vowel sounds 2016 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 140:3, s. 1707-1718 Journal article (peer-reviewed)abstract For many years, the vocal tract shape has been approximated by one-dimensional (1D) area functions to study the production of voice. More recently, 3D approaches allow one to deal with the complex 3D vocal tract, although area-based 3D geometries of circular cross-section are still in use. However, little is known about the influence of performing such a simplification, and some alternatives may exist between these two extreme options. To this aim, several vocal tract geometry simplifications for vowels [É‘], [i], and [u] are investigated in this work. Six cases are considered, consisting of realistic, elliptical, and circular cross-sections interpolated through a bent or straight midline. For frequencies below 4â€“5 kHz, the influence of bending and cross-sectional shape has been found weak, while above these values simplified bent vocal tracts with realistic cross-sections are necessary to correctly emulate higher-order mode propagation. To perform this study, the finite element method (FEM) has been used. FEM results have also been compared to a 3D multimodal method and to a classical 1D frequency domain model.
11.	Askenfelt, Anders (author) Between the frog and the tip : Bowing gestures and bow-string interaction in violin playing (invited) 2008 In: Program abstracts for Acoustics‘08 Paris. - : Acoustical Society of America (ASA). ; , s. 3656- Conference paper (other academic/artistic)abstract The motion of the bow gives a natural visualization of a string performance. Watching the player's bowing may augment the communicative power of the music, but all relevant bow control parameters are not easy to capture by a spectator. The string player controls volume of sound and tone quality continuously by coordination of three basic bowing parameters (bow velocity, bow‐bridge distance, and bow force), which set the main conditions for the bow‐string interaction. At a more detailed level of description, the tilting of the bow, which among other things controls the effective width of the bow hair, enters into the model. On a longer time scale, pre‐planned coordination schemes ('bowing gestures'), including the basic bowing parameters and the angles between the path of the bow and the strings, builds the performance. Systems for recording bowing parameters will be reviewed and results from old and current studies on bowing gestures presented. The player's choice and coordination of bowing parameters are constrained both in attacks and 'steady‐state' according to bow‐string interaction models. Recent verifications of these control spaces will be examined. Strategies for starting notes and examples of how players do in practice will be presented and compared with listeners' preferences.
12.	Asraf, Daniel, et al. (author) Phenomenological detectors for crack echo families in elastic solids 2004 In: Journal of the Acoustical Society of America. - 0001-4966 .- 1520-8524. ; 116:1, s. 379-388 Journal article (peer-reviewed)abstract The potential performance of low-complexity phenomenological detectors for crack echo families in elastic solids is evaluated. Ultrasonic echoes from a strip-like crack residing in an isotropic elastic solid with coarse microstructure are considered and the achieved detector performance is compared to the theoretical upper bounds (constrained only by the underlying physics) obtained by means of a recently presented physics-based optimal detector. A phenomenological signal model for the scattering process is formulated based on the time-domain impulse-response method and used to derive detectors of low numerical complexity which are dependent on a small number of parameters. The proposed detectors are compared in terms of receiver operating characteristic curves, which are computed by means of Monte Carlo simulations for the case of a strip-like crack with uncertain angular orientation. The minimum probability of error criterion is used to optimize the detector parameters for the simulation study and shown to be useful even for small training data sets. These results show that the proposed detectors have close to optimal performance in particular for the case of high signal-to-noise ratios.
13.	Auregan, Yves, et al. (author) Low frequency sound attenuation in a flow duct using a thin slow sound material 2016 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 139:5, s. EL149-EL153 Journal article (peer-reviewed)abstract A thin subwavelength material that can be flush mounted in a duct and that gives an attenuation band at low frequencies in air flow channels is presented. To decrease the material thickness, the sound is slowed in the material using folded side branch tubes. The impedance of the material is compared to the optimal value given by the Cremer condition, which can differ greatly from the air characteristic impedance. Grazing flow on this material increases the losses at the interface between the flow and the material.
14.	Axelsson, Östen, et al. (author) A principal components model of soundscape perception 2010 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 128:5, s. 2836-2846 Journal article (peer-reviewed)abstract There is a need for a model that identifies underlying dimensions of soundscape perception, and which may guide measurement and improvement of soundscape quality. With the purpose to develop such a model, a listening experiment was conducted. One hundred listeners measured 50 excerpts of binaural recordings of urban outdoor soundscapes on 116 attribute scales. The average attribute scale values were subjected to principal components analysis, resulting in three components: Pleasantness, eventfulness, and familiarity, explaining 50, 18 and 6% of the total variance, respectively. The principal-component scores were correlated with physical soundscape properties, including categories of dominant sounds and acoustic variables. Soundscape excerpts dominated by technological sounds were found to be unpleasant, whereas soundscape excerpts dominated by natural sounds were pleasant, and soundscape excerpts dominated by human sounds were eventful. These relationships remained after controlling for the overall soundscape loudness (Zwicker’s N10), which shows that ‘informational’ properties are substantial contributors to the perception of soundscape. The proposed principal components model provides a framework for future soundscape research and practice. In particular, it suggests which basic dimensions are necessary to measure, how to measure them by a defined set of attribute scales, and how to promote high-quality soundscapes.
15.	Axelsson, Östen (author) Progress in soundscape research requires a common agenda 2011 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:4, s. 2495-2495 Journal article (other academic/artistic)abstract It is commonly believed that progress and success in any field requires competition. This is probably true, but this belief implies that all competitors have a common view on the objectives. There would not be much competition if all parties ran off in opposite directions, striving to achieve different goals. Nor would it lead to much progress. The present session calls for networking and international collaboration in soundscape research. For such collaboration to be successful, it is critical to agree on a common agenda; a mission; an objective. Recent development in soundscape research makes evident that the objective must be practical and applicable. Our minds must be set to implementing soundscape research in practice to avoid exhausting academic debates, which tend to be ends in themselves and do not contribute to progress. Two excellent, recent examples of international collaboration in soundscape research, contributing to progress, are ISO/TC 43/SC 1/WG 54 and the European COST Action TD0804 “Soundscape of European Cities and Landscapes.” Both illustrate the need for international and interdisciplinary collaboration among acousticians, architects, and urban planners to accelerate progress in soundscape research. The present paper presents possible topics for a common agenda in soundscape research.
16.	Axelsson, Östen, et al. (author) Soundscape assessment. 2005 In: The Journal of the Acoustical Society of America. - 0001-4966. ; 117:4, s. 2591-2592 Journal article (other academic/artistic)abstract In order to improve the quality of the soundscape it is necessary to know its descriptive and evaluative properties, and the relationships between these properties. This was explored in a listening experiment with 100 participants (48 women, 52 men; mean age 25,6 years). Each participant scaled 5 out of 50 soundscapes with regard to 116 single verbal attributes, using a visual analogue scale of agreeableness. In addition, acoustical properties of the soundscapes were assessed. A principal component analysis identified two major evaluative components, labeled Hedonic Tone and Eventfulness. Furthermore it was found that the mere presence of common sound sources, regardless of sound level, correlated significantly with these evaluative components. Technological sounds (e.g., traffic noise) were negatively associated with both Hedonic Tone and Eventfulness, while a positive association was found between Hedonic Tone and sounds of nature (e.g., bird song), and a positive association was found between Eventfulness and human sounds (e.g., human voices). These relationships lead to the hypothesis that introduction of nature and human sounds, in combination with the reduction of technological sounds may improve the quality of soundscapes considerably.
17.	Axelsson, Östen (author) The ISO 12913 series on soundscape : An update, May 2012 2012 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 131:4 Journal article (peer-reviewed)abstract In February 2009 the working group ISO/TC 43/SC 1/WG 54 “Perceptual assessment of soundscape quality”, of the International Organization for Standardization (ISO), begun preparing the first International Standard on soundscape “ISO 12913-1 Acoustics — Soundscape — Part 1: Definition and conceptual framework”. This paper presents the latest version of the definition of “soundscape” and its conceptual framework. At its current state of development the framework highlights seven general concepts and their relationships: (1) sound sources, (2) acoustic environment, (3) auditory sensations, (4) interpretation of auditory sensations, (5) responses, (6) context, and (7) outcomes. By providing a standard reference, the working group aims at international consensus in order to avoid ambiguity, and to enable conceptual progress in soundscape research. ISO 12913-1 is expected to be published as an International Standard in 2015. Subsequent parts of the ISO 12913 series will deal with minimum reporting requirements in soundscape research, and methods for measuring soundscape quality.
18.	Axelsson, Östen (author) Tower of Babel, or why bother about international standards? 2011 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:4, s. 2467-2467 Journal article (other academic/artistic)abstract While a vast nation like the USA has the capacity to be self-sufficient, many countries lack this privilege. Take Sweden as an example, a small country in northern Europe with a population of 9 million. Swedes are proud to be international. And they should, because how could a nation, which since the days of the Vikings has depended on international trade, sustain itself without a global economy. International standards support the development within this global economy, just like English as business language facilitates global collaboration. Imagine humanity without these common frames of reference.
19.	Axelsson, Östen, et al. (author) Validation of the Swedish soundscape-quality protocol 2012 In: Journal of the Acoustical Society of America. - New York : Acoustical Society of America (ASA). - 0001-4966. ; 131:4, s. 3474- Journal article (other academic/artistic)abstract The Swedish Soundscape-Quality Protocol was developed to help non-experts (e.g., officials working for municipalities rather than soundscaperesearchers) to make informed, accurate measurements of soundscape quality. The Protocol has hitherto been used in England, France, Italy, Spain, Sweden, and The Netherlands; a Korean version is being developed. Based on field studies – soundwalks in urban residential areas, recreational areas, and parks – the present paper reports on the psychometric properties of the scales of the Protocol. Participants were residents, or visitors to the areas and their results support the reliability and validity of the scales in the Protocol. Because high acoustic quality has a greater effect in visually attractive than in visually poor areas, the Swedish Soundscape-Quality Protocol includes scales for cross-sensory tabulation. These are sound source identification – sounds from humans, nature and technology – attribute scales (e.g., eventful, exciting, pleasant, and calm), overall soundscape quality, and concomitant visual impressions. In brief, the Swedish Soundscape-Quality Protocol is an easy to use and practical tool for measuringsoundscape quality. It has the potential to help operationalize how soundscapes can be measured in “quiet areas” to meet a future guideline value of the World Health Organization.
20.	Axelsson, Östen, et al. (author) Water features and acoustic diversity of urban parks 2011 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:4, s. 2533-2533 Journal article (other academic/artistic)abstract Water features are well-acknowledged in architecture and urban planning for their visual characteristics. But, how do water features contribute to acoustic diversity and soundscape quality? Visitors in an urban park were recruited to complete a questionnaire on how they perceived the park including its soundscape. Meanwhile, the soundscape was manipulated by turning a fountain on or off at irregular hours. The fountain sounds had a positive effect on soundscape quality in an area close to the fountain, by masking background road-traffic noise. The fountain sound also masked other natural sounds, which may have a negative influence on acoustic diversity and soundscape quality. In addition, some participants may have mistaken the fountain sounds for distant road-traffic noise. Hence, when introducing a water feature in an urban park it is necessary to consider the acoustic characteristics of the water sounds, as well as the placement of the water feature.
21.	Babisch, W, et al. (author) Exposure modifiers of the relationships of transportation noise with high blood pressure and noise annoyance 2012 In: The Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 132:6, s. 3788-3808 Journal article (peer-reviewed)
22.	Balling, Laura, et al. (author) Investigating lexical competition and the cost of phonemic restoration 2017 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 142:6, s. 3603-3612 Journal article (peer-reviewed)abstract Due to phonemic restoration, listeners can reliably perceive words when a phoneme is replaced with noise. The cost associated with this process was investigated along with the effect of lexical uniqueness on phonemic restoration, using data from a lexical decision experiment where noise replaced phonemes that were either uniqueness points (the phoneme at which a word deviates from all nonrelated words that share the same onset) or phonemes immediately prior to these. A baseline condition was also included with no noise-interrupted stimuli. Results showed a significant cost of phonemic restoration, with 100 ms longer word identification times and a 14% decrease in word identification accuracy for interrupted stimuli compared to the baseline. Regression analysis of response times from the interrupted conditions showed no effect of whether the interrupted phoneme was a uniqueness point, but significant effects for several temporal attributes of the stimuli, including the duration and position of the interrupted segment. These results indicate that uniqueness points are not distinct breakpoints in the cohort reduction that occurs during lexical processing, but that temporal properties of the interrupted stimuli are central to auditory word recognition. These results are interpreted in the context of models of speech perception.
23.	Bard, Delphine, et al. (author) Human footsteps induced floor vibration. 2008 In: The Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 123:5, s. 3356-3356 Journal article (peer-reviewed)abstract The generation of the impact sound by the act of the human walk involves two factors, the characters of the footfall and the shape of the induced floor deflection. The footfall noise is created by the impact excitation and the characters of the footfall depend on the foot-ware: the heels and the frequencies of the footfall. The shape of the floor deflection depends rather on the geometrical walking pattern and the construction of the floor structure. In this investigation, the vibration patter of the light-weight construction floor is created by the same walking object, a male with common height. The excitation from the person to the floor in the FE simulations is a function of the length of the foot and the weight of the walking object. The geometrical time history is of the foot step allows it to have different directions in the room. Since the excitation is assumed to be deterministic, differences between the excitation frequencies are estimated from the video records. The goal of this investigation is to determine the difference of the floor structure deflections between two different walking paths: one is perpendicular to the bearing beams and the other is the diagonal path.
24.	Bard, Delphine, et al. (author) Newborn pain cry analysis based on pitch frequency tracking. 2008 In: The Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 123:5 Journal article (peer-reviewed)abstract The aim of the newborn pain cry analysis is to test the hypothesis that cry can be used as a tool to detect signs of nocioceptive pain. Previous studies applying signal processing techniques to analyze the sound of these cries have been done. The subject of this paper is to adapt and improve the original method with the help of new signal processing methods. The pitch frequency is extracted from the waveform of the recorded babies' cries using time domain methods. The fluctuations of this parameter are analyzed in terms of jitter. In particular, a sliding buffer approach is presented, as well as an improvement of the Average Mean Difference Function (AMDF). Comparison between original and news results has been done.
25.	Benetos, Emmanouil, et al. (author) Automatic transcription of Turkish microtonal music 2015 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966. ; 138:4, s. 2118-2130 Journal article (peer-reviewed)abstract Automatic music transcription, a central topic in music signal analysis, is typically limited to equal-tempered music and evaluated on a quartertone tolerance level. A system is proposed to automatically transcribe microtonal and heterophonic music as applied to the makam music of Turkey. Specific traits of this music that deviate from properties targeted by current transcription tools are discussed, and a collection of instrumental and vocal recordings is compiled, along with aligned microtonal reference pitch annotations. An existing multi-pitch detection algorithm is adapted for transcribing music with 20 cent resolution, and a method for converting a multi-pitch heterophonic output into a single melodic line is proposed. Evaluation metrics for transcribing microtonal music are applied, which use various levels of tolerance for inaccuracies with respect to frequency and time. Results show that the system is able to transcribe microtonal instrumental music at 20 cent resolution with an F-measure of 56.7%, outperforming state-of-the-art methods for the same task. Case studies on transcribed recordings are provided, to demonstrate the shortcomings and the strengths of the proposed method.
26.	Berglund, B, et al. (author) Sources and effects of low-frequency noise 1996 In: The Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966. ; 99:5, s. 2985-3002 Journal article (peer-reviewed)
27.	Bergman, Penny, 1982, et al. (author) Emotion and meaning in interpretation of sound sources 2008 In: Journal of Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966. ; 123, s. 3567- Journal article (peer-reviewed)abstract Research regarding the perception of sound focuses in large on the acoustical properties of the sound. We argue that, for a more complete picture of sound perception, one must take the non‐physical properties into account. By changing the emotional descriptor of a sound the perception in terms of level of annoyance will change. The present study investigates how a priming picture placing the origin of the sound in either a positive or negative environment affects the level of annoyance to same sound. Three different sounds were used in the experiment, all based on pink noise. The participants were, in the beginning of each sound, exposed to a picture telling where the sound originated. The picture was either a positive environment (a picture of a waterfall) or a negative environment (a picture of a larger factory). While listening to the sounds the participants completed different performance tasks. In the end of each sound the participants rated the level of annoyance. Results show that the annoyance ratings are significantly lower when primed with a positive picture. Results also indicate that for more attention demanding tasks this correlation is stronger. The findings are discussed in relation to theories of sound perception.
28.	Bergman, Penny, 1982, et al. (author) Perceptual and emotional categorization of sound 2009 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 126:6, s. 3156-3167 Journal article (peer-reviewed)abstract This paper investigates how different types of data from psychoacoustical experiments may be combined to render further knowledge about the mechanisms underlying sound perception. Two studies were conducted with auditory alerts of short duration. First, an experiment where participants rated the dissimilarity among the auditory alerts was performed. This resulted in a two-dimensional multi-dimensional scaling solution. Second, an experiment where participants evaluated the stimuli with semantic descriptors and rated their emotional reactions to the sounds was performed. The output of this experiment was a reduced set of underlying perceptual and emotional dimensions. The results of the two experiments were then integrated by the use of multi-dimensional perceptual unfolding and a set mediation analyses. The integrative analyses showed that part of the cognitive categorization of the semantic descriptors was mediated by the emotional reactions to the sounds. The results are discussed in relation to theories of auditory perception and emotional response categorization.
29.	Beskow, Jonas (author) Spoken and non-verbal interaction experiments with a social robot 2016 In: The Journal of the Acoustical Society of America. - : Acoustical Society of America. - 0001-4966. Conference paper (peer-reviewed)abstract During recent years, we have witnessed the start of a revolution in personal robotics. Once associated with highly specialized manufacturing tasks, robots are rapidly starting to become part of our everyday lives. The potential of these systems is far-reaching; from co-worker robots that operate and collaborate with humans side-by-side to robotic tutors in schools that interact with humans in a shared environment. All of these scenarios require systems that are able to act and react in a social way. Evidence suggests that robots should leverage channels of communication that humans understand—despite differences in physical form and capabilities. We have developed Furhat—a social robot that is able to convey several important aspects of human face-to-face interaction such as visual speech, facial expression, and eye gaze by means of facial animation that is retro-projected on a physical mask. In this presentation, we cover a series of experiments attempting to quantize the effect of our social robot and how it compares to other interaction modalities. It is shown that a number of functions ranging from low-level audio-visual speech perception to vocabulary learning improve when compared to unimodal (e.g., audio-only) settings or 2D virtual avatars.
30.	Bilbao, Stefan, et al. (author) Incorporating Source Directivity in Wave-based Virtual Acoustics: Time-domain Models and Fitting to Measured Data 2019 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 146:4, s. 2692-2703 Journal article (peer-reviewed)abstract The modeling of source directivity is a problem of longstanding interest in virtual acoustics and auralisation. This remains the case for newer time domain volumetric wave-based approaches to simulation such as the finite difference time domain method. In this article, a spatio-temporal model of acoustic wave propagation, including a source term is presented. The source is modeled as a spatial Dirac delta function under the action of a series of differential operators associated with the spherical harmonic functions. Each term in the series gives rise to the directivity pattern of a given spherical harmonic, and is separately driven through a time domain filtering operation of an underlying source signal. Such a model is suitable for calibration against measured frequency-dependent directivity patterns and a procedure for arriving at time domain filters for each spherical harmonic channel is illustrated. It also yields a convenient framework for discretisation, and a simple strategy is presented, yielding a locally-defined operation over the spatial grid. Numerical results, illustrating various features of source directivity, including the comparison of measured and synthetic directivity patterns, are presented.
31.	Bilbao, Stefan, et al. (author) Modeling continuous source distributions in wave-based virtual acoustics 2020 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 148:6, s. 3951-3962 Journal article (peer-reviewed)abstract All acoustic sources are of finite spatial extent. In volumetric wave-based simulation approaches (including, e.g., the finite difference time domain method among many others), a direct approach is to represent such continuous source distributions in terms of a collection of point-like sources at grid locations. Such a representation requires interpolation over the grid and leads to common staircasing effects, particularly under rotation or translation of the distribution. In this article, a different representation is shown, based on a spherical harmonic representation of a given distribution. The source itself is decoupled from any particular arrangement of grid points, and is compactly represented as a series of filter responses used to drive a canonical set of source terms, each activating a given spherical harmonic directivity pattern. Such filter responses are derived for a variety of commonly encountered distributions. Simulation results are presented, illustrating various features of such a representation, including convergence, behaviour under rotation, the extension to the time varying case, and differences in computational cost relative to standard grid-based source representations.
32.	Bjerva, Johannes, et al. (author) Preceding non-linguistic stimuli affect categorisation of Swedish plosives 2012 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 131:4 Journal article (peer-reviewed)abstract Speech perception is highly context-dependent. Sounds preceding speech stimuli affect how listeners categorise the stimuli, regardless of whether the context consists of speech or non-speech. This effect is acoustically contrastive; a preceding context with high-frequency acoustic energy tends to skew categorisation towards speech sounds possessing lower-frequency acoustic energy and vice versa (Mann, 1980; Holt, Lotto, Kluender, 2000; Holt, 2005). Partially replicating Holt's study from 2005, the present study investigates the effect of non-linguistic contexts in different frequency bands on speech categorisation. Adult participants (n=15) were exposed to Swedish syllables from a speech continuum ranging from /da/ to /ga/ varying in the onset frequencies of the second and third formants in equal steps. Contexts preceding the speech stimuli consisted of sequences of sine tones distributed in different frequency bands: high, mid and low. Participants were asked to categorise the syllables as /da/ or /ga/. As hypothesised, high frequency contexts shift the category boundary towards /da/, while lower frequency contexts shift the boundary towards /ga/, compared to the mid frequency context.
33.	Bjurström, Henrik, 1983-, et al. (author) Detecting the thickness mode frequency in a concrete plate using backward wave propagation 2016 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 139:2, s. 649-657 Journal article (peer-reviewed)abstract Material stiffness and plate thickness are the two key parameters when performing quality assurance/quality control on pavement structures. In order to estimate the plate thickness non-destructively, theImpact Echo (IE) method can be utilized to extract the thickness resonance frequency. An alternativeto IE for estimating the thickness resonance frequency of a concrete plate, and to subsequently enablethickness determination, is presented in this paper. The thickness resonance is often revealed as asharp peak in the frequency spectrum when contact receivers are used in seismic testing. Due to a lowsignal-to-noise ratio, IE is not ideal when using non-contact microphone receivers. In studying thecomplex Lamb wave dispersion curves at a frequency infinitesimally higher than the thickness frequency,it is seen that two counter-directed waves occur at the same frequency but with phase velocitiesin opposite directions. Results show that it is possible to detect the wave traveling with anegative phase velocity using both accelerometers and air-coupled microphones as receivers. Thisalternative technique can possibly be used in non-contact scanning measurements based on aircoupled microphones.
34.	Bodén, Hans (author) Experimental source characterization techniques for studying the acoustic properties of perforates under high level acoustic excitation 2011 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:5, s. 2639-2647 Journal article (peer-reviewed)abstract This paper discusses experimental techniques for obtaining the acoustic properties of in-duct samples with non-linear acoustic characteristic. The methods developed are intended both for studies of non-linear energy transfer to higher harmonics for samples only accessible from one side such as wall treatment in aircraft engine ducts or automotive exhaust systems and for samples accessible from both sides such as perforates or other top sheets. When harmonic sound waves are incident on the sample nonlinear energy transfer results in sound generation at higher harmonics at the sample (perforate) surface. The idea is that these sources can be characterized using linear system identification techniques similar to one-port or two-port techniques which are traditionally used for obtaining source data for in-duct sources such as IC-engines or fans. The starting point will be so called polyharmonic distortion modeling which is used for characterization of nonlinear properties of microwave systems. It will be shown how acoustic source data models can be expressed using this theory. Source models of different complexity are developed and experimentally tested. The results of the experimental tests show that these techniques can give results which are useful for understanding non-linear energy transfer to higher harmonics.
35.	Boij, Susann (author) Flow effects on the acoustic end correction of a sudden in-duct area expansion 2009 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 126:3, s. 995-1004 Journal article (peer-reviewed)abstract For scattering of plane waves at a sudden area expansion in a duct, the presence of flow may significantly alter the reactive properties. This paper studies the influence of a mean flow field and unstable separated flow on the reactive properties of the expansion, formulated as an end correction. Theoretical and experimental results show that the expansion end correction is significantly affected by the flow and hydrodynamic waves excited at the edge of the expansion. The effects are different in three regions where the Strouhal number is small, of order 1, and large. The influence is most significant at Strouhal numbers of the order 1, with specific limiting values for large and small Strouhal numbers, respectively. In the analytic model, an important feature is the shear layer at the edge modeled as a vortex sheet with the unsteady Kutta condition applied at the edge. The influence of Mach number, Helmholtz number, and area expansion ratio is studied, and a quasistationary, small Strouhal number, approximation yields an expression for the end correction. Further, the influence of edge condition is explored, emphasizing the importance of interaction between sound and unsteady vorticity shedding at the edge of the area expansion.
36.	Bolin, Karl, et al. (author) Air-borne sound generated by sea waves 2010 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 127:5, s. 2771-2779 Journal article (peer-reviewed)abstract This paper describes a semi-empiric model and measurements of air-borne sound generated by breaking sea waves. Measurements have been performed at the Baltic Sea. Shores with different slopes and sediment types have been investigated. Results showed that the sound pressure level increased from 60 dB at 0.4 m wave height to 78 dB at 2.0 m wave height. The 1/3 octave spectrum was dependent on the surf type. A scaling model based on the dissipated wave power and a surf similarity parameter is proposed and compared to measurements. The predictions show satisfactory agreement to the measurements. (C) 2010 Acoustical Society of America. [DOI: 10.1121/1.3327815]
37.	Bolin, Karl, 1977-, et al. (author) An investigation of the influence of the refractive shadow zone on wind turbine noise 2020 In: Journal of the Acoustical Society of America. - : Acoustical Society of America. - 0001-4966 .- 1520-8524. ; 148:2, s. EL166-EL171 Journal article (peer-reviewed)abstract This article aims to investigate if the proportion of the rotor area of a wind turbine that is in the refractive shadow zone according to a ray tracing algorithm coupled to meteorological forecast data is correlated to sound levels and amplitude modulation. The acoustic station is situated 950 m from a wind farm in Northern Sweden and the measurement period is seven months. On average, 1.9 dBA lower sound levels are measured when the part of the rotor disk of the closest turbine is in the refractive shadow zone. A higher probability of amplitude modulations are observed when around half of the turbine rotor is within the refractive shadow zone compared to conditions with no shadow zone present.
38.	Bolin, Karl, et al. (author) Long range sound propagation over a sea surface 2009 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 126:5, s. 2191-2197 Journal article (peer-reviewed)abstract This paper describes methodology and results from a model-based analysis of data on sound transmission from controlled sound sources at sea to a 10-km distant shore. The data consist of registrations of sound transmission loss together with concurrently collected atmospheric data at the source and receiver locations. The purpose of the analysis is to assess the accuracy of methods for transmission loss prediction in which detailed data on the local geography and atmospheric conditions are used for computation of the sound field. The results indicate that such sound propagation predictions are accurate and reproduce observed variations in the sound level as function of time in a realistic way. The results further illustrate that the atmospheric model must include a description of turbulence effects to ensure predicted noise levels to remain realistically high during periods of sound shadow. (C) 2009 Acoustical Society of America. [DOI: 10.1121/1.3238236]
39.	Bolin, Karl, et al. (author) Long term estimations of low frequency noise levels over water from an off-shore wind farm 2014 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 135:3, s. 1106-1114 Journal article (peer-reviewed)abstract This article focuses on computations of low frequency sound propagation from an off-shore wind farm. Two different methods for sound propagation calculations are combined with meteorological data for every 3 hours in the year 2010 to examine the varying noise levels at a reception point at 13 km distance. It is shown that sound propagation conditions play a vital role in the noise impact from the off-shore wind farm and ordinary assessment methods can become inaccurate at longer propagation distances over water. Therefore, this paper suggests that methodologies to calculate noise immission with realistic sound speed profiles need to be combined with meteorological data over extended time periods to evaluate the impact of low frequency noise from modern off-shore wind farms.
40.	Boström, Anders E, 1951 (author) Acoustic scattering by a sound-hard rectangle 1991 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 90, s. 3344-3347 Journal article (peer-reviewed)abstract The scattering of an incoming plane wave by a sound-hard infinitely thin rectangle is considered. Starting from a double spatial Fourier transform representation of the scattered wave, a matching of the conditions in the plane of the rectangle leads to an integral equation for the potential jump across the rectangle. The jump is expanded in a double series in Chebyshev polynomials which fulfill the right edge conditions (but no special measures are taken for the corners where the right conditions are anyway unknown). The integral equation is thus discretized and the only tricky part is the computations of double integrals in the systen matrix where special care must be excercised. A double stationary phase analysis gives the scattered far fields, and some numerical examples of total scattering cross sections are given.
41.	Boström, Anders E, 1951 (author) Multiple scattering of elastic waves by bounded obstacles 1980 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 67, s. 399-413 Journal article (peer-reviewed)abstract The transition matrix method for stationary elastic waves is extended to a great class of obstacles characterized by piecewise constant properties. First, the translation properties of the basis functions is used to treat two and, then, then several homogeneous obstacles, and thereafter an obstacle with consecutively enclosing layers is considered. It is then indicated how these two basic methods of combination can be applied tp treat more complex cases, including an obstacle consisting of several nonenclosing parts. Finally, we give some numrecal applications of configurations of spherical and nonspherical obstacles in and below the resonance region.
42.	Boström, Anders E, 1951 (author) Propagating, damped, and leaky surface waves on the corrugated traction-free boundary of an elastic half-space 1989 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 85, s. 1549-1555 Journal article (peer-reviewed)abstract The dispersion relation for surface waves on the corrugated boundary (periodic in one direction and constant in the other) of an elastic half-space is derived using a modal approach, and the result is shown to be equivalent to that derived by the null-field approach. The dispersion relation is solved numerically for roots on all Riemann sheets for varying corrugation heights, frequencies, and angles of propagation. Many of the roots move on several sheets, and this leads to zero, one, or two roots residing on the physical sheets.
43.	Boström, Anders E, 1951, et al. (author) Propagation of elastic surface waves along a cylindrical cavity and their excitation by a point force 1982 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 72, s. 998-1004 Journal article (peer-reviewed)abstract The existence of surface wave modes, propagating along on infinite cylindrical cavity in an elastic medium, is established for every integer m, where m is the azimuthal mode number. These waves are analogous to the Rayleigh wave on a half-space, being confined to the immediate vicinity of the cavity. The modes exhibit dispersion and have a cutoff frequency that increases with m, except for the flexural (m=1) mode which exists at all frequencies. At cutoff the phase velocity is equal to that of the shear waves and decreases, with increasing frequency, to that of the Rayleigh wave. We present results for the group velocities and displacement and stress fields of the modes and also exhibit the effect of various point forces acting near the cavity. In the vicinity of the cavity, not too near the point force, the surface wave contribution dominates the total displacement field.
44.	Boström, Anders E, 1951 (author) Scattering by a smooth elastic obstacle 1980 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 67, s. 1904-1913 Journal article (peer-reviewed)abstract In the present paper we adapt the transition matrix method to the case of a smooth elastic obstacle. The boundary conditions employed are discussed in some detail and are seen to be responsible for the fact that the rather complicated formal solution in many respects resembles that of an elastic obstacle in a fluid. Comparisons are made between the smooth and the usually employed welded obstacles, and for spheres approximate expressions are given for the transition matrices in the long wavelength limit. Numerical results (cross sections and surface stresses) are given for spheres and spheroids, and it is then seen that often the smooth and welded obstacles, at least qualitatively, show similar features.
45.	Boström, Anders E, 1951, et al. (author) Scattering of acoustic waves by a circular disc in the interface between two fluids 1991 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 90, s. 3338-3343 Journal article (peer-reviewed)abstract The scattering of acoustic waves by a sound-hard circular disc situated in the planar interface between two different fluids is considered. The incident wave is taken as a plane wave and a Hankel transform representation of the scattered field is used. After some manipulations using the boundary conditions, this leads to an integral equation over the disc for the potential jump across the disc. This jump is expanded in a series of Legendre functions which fulfill the correct edge condition and the integral equation is projected on the same set of Legendre functions. The far fields are calculated and the implications of energy conservation are explored and used as a numerical check. A few numerical computations showing the disc-scattered far field amplitude and the total scattering cross section are given and are shown to compare favorably with the expectations from simple ray theory at higher frequencies.
46.	Boström, Anders E, 1951 (author) Scattering of acoustic waves by a layered elastic obstacle in a fluid - an improved null field appraoch 1984 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 76, s. 588-593 Journal article (peer-reviewed)abstract Scattering by a layered elastic obstacle submerged in a fluid is considered. The null field approach (T-matrix method) is used, but the method is modified so that all surface fields can be expanded in spherical harmonics. The resulting method is then compared with the conventional null field approach (which uses expansions in regular wavefunctions), and it is concluded that the present method is better in general. It is, however, doubtful if the null field approach is applicable to cases where there is no sphere that circumscribes the core and inscribes the outer surface. Some numerical results are given for a layered spheroid and superspheroid.
47.	Boström, Anders E, 1951 (author) Scattering of stationary acoustic waves by an elastic obstacle immersed in a fluid 1980 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 67, s. 390-398 Journal article (peer-reviewed)abstract The scattering of stationary acoustic waves by a bounded elastic obstacle in an inviscid fluid is considered. The developed formalism is an extension of the transition matrix method, which has been given by Waterman for acoustic, electromagnetic, and elastic scattering. In fact the problem at hand is more complex than the elastic case, something which is apparent in the solution. It is possible to obtain some different forms for the transition matrix, depending upon whether the Rayleigh hypothesis enters or not. It is worthy of notice that the more general formalism, i.e., the one not assuming the Rayleigh hypothesis, is also the more efficient numerically. Numerical results are given for spheroids and an object resembling the number "8".
48.	Boström, Anders E, 1951 (author) The null-field approach in series form - the direct and inverse problems 1986 In: Journal of the Acoustical Society of America. - 1520-8524 .- 0001-4966. ; 79, s. 1223-1229 Journal article (peer-reviewed)abstract The direct and inverse scattering problem in two-dimensional acoustics at a fixed frequency are considered. It is shown how the null-field approach can be modified so that the Q matrix (which in a straightforward manner gives the transition matrix) is obtained as a series instead of an integral. For an obstacle which is a perturbation of a circle this series form gives an approximate, very explicit, expression for the transition matrix. A few numerical examples are given to show the utility and limitations of this approximation. For the inverse problem, the series form of Q gives a system of nonlinear polynomial equations which are solved by the imbedding method. Some numerical examples show that quite accurate results are obtained by this method in cases where the system of equations can be kept small. The linear approximation of the system of polynomial equations yields a method that works surprisingly well and which is also promising for the more difficult three-dimensional and vector problems.
49.	Botteldooren, Dick, et al. (author) An LAeq is not an LAeq. 2005 In: Journal of the Acoustical Society of America. - 0001-4966. ; 117:4, s. 2616- Journal article (other academic/artistic)abstract Classical dose response relationships for environmental noise annoyance have been based on Ldn or Lden. These exposure measures are essentially based on an energy averaging measure, LAeq. Differences between groups of sources (e.g., continuous or event based) are accounted for by using separate dose-effect relationships. In society today, one often sees that event loudness is traded for number of events which is perfectly acceptable within the LAeq based annoyance concept. Clearly a more unified theory for noise annoyance is needed to fully account for the effect of such trade-offs. In this paper a model implementing such a theory is presented. The perceptual model starts from the premises that a sound event has to be noticed for it to contribute to overall annoyance. The model accounts for the fact that noticing a noise event not only depends on the level of the event itself but also on background noise, sound insulation and acoustic characteristics of the dwelling, level of attention, etc. The severity of the effect of a noticed sound on overall annoyance is assumed to primarily depend on the signal to noise ratio. The model allows to account for modifiers such as previous exposure, noise sensitivity, and coping. The model results are compared to the findings of a recent field experiment. Conclusions based on calculated and experimental trends are presented.
50.	Brunskog, Jonas, et al. (author) Absorption and scattering by perforated facings with periodic narrow slits 2022 In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 151:3, s. 1847-1859 Journal article (peer-reviewed)abstract This paper develops a theory for the sound absorption and scattering of perforated slit absorbers.A rigid plane, perforated periodically in one dimension with absorbing slits, scatters incoming sound waves as discrete wave components in different directions. The absorbing slits are assumed to be line-like in the sense that their width is much shorter than the wavelengths.The equation for the sound field is solved in the wavenumber domain. The slits are described with an impedance description, assuming local reaction of the slits (typically a Helmholtz resonator).The solution is found by means of an inverse transform, back to the spatial domain. This results in an explicit formulation of the sound field, including a sum consisting of components that either radiate energy in discrete directions or are surface waves.A similar sum is also included in a term that can be interpreted as radiation impedance. The explicit expressions for the absorption and scattering coefficients are found with the aid of the radiating part of the scattered and reflected field.Numerical results of the absorption and scattering coefficients are presented. The result is verified with finite element method and compared with the result from an alternative general formulation of the problem.

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