Acoustic Constraints Research Articles

A rule-based framework for capturing geometric characteristics in design: A study of façade analysis for acoustic behaviour in urban space

In urban acoustics, the design of built environment substantially impacts the environmental noise of our everyday lives, as the built environment constantly reflects the sounds of human or non-human actors in its vicinity. The effects produced by these reflected sounds significantly depend on the geometric characteristics of the surrounding building façades. Despite their impact, the façade characteristics are often excluded from urban acoustic simulation models. As a result, sound reflection and scattering that are specifically related to building façades remain largely unexplored in noise control at the urban scale. Inspired by computational design tools used for exploring room acoustics, we investigate how a computational approach enables the analysis of geometric characteristics of façades to simulate urban acoustics during early design processes. This paper introduces a rule-based characterisation framework that enables the representation of geometric façade characteristics and their relationships with acoustic constraints in the form of rules. Our first results showed how these rules allowed for capturing and reconstructing façade geometries based on the given acoustic constraints. We believe that this novel approach empowers designers to describe their initial design ideas in a formalism that can be dynamically adapted to various dimensions, such as urban acoustics, and to reconstruct the form throughout the design process.

Who is singing? Voice recognition from spoken versus sung speech.

Singing is socially important but constrains voice acoustics, potentially masking certain aspects of vocal identity. Little is known about how well listeners extract talker details from sung speech or identify talkers across the sung and spoken modalities. Here, listeners (n = 149) were trained to recognize sung or spoken voices and then tested on their identification of these voices in both modalities. Learning vocal identities was initially easier through speech than song. At test, cross-modality voice recognition was above chance, but weaker than within-modality recognition. We conclude that talker information is accessible in sung speech, despite acoustic constraints in song.

A new Building Regulation for overheating: practical considerations for the acoustic constraints

A new Building Regulation to mitigate overheating applies in England from June 2022. A requirement of the regulation is that the strategy to mitigate overheating must be usable, considering occupants' safety and comfort. If internal noise levels exceed 40 dBA Lnight, or 55 dB LAmax more than 10 times a night, then windows cannot be assumed to be open during the night time period. This paper discusses a triage process to consider the noise risk, the practical methods and uncertainties in the noise survey, environmental noise modelling, calculation of facade sound insulation with windows sufficiently open to mitigate overheating, and demonstrating compliance. Potential solutions for natural ventilation and mechanically assisted ventilation are outlined. Until now, the environmental noise impact on new dwellings has been controlled through the planning regime, where environmental health officers have acoustics expertise. The Building Regulations are enforced by building control officers, who may have little or no training in acoustics. More than 30 % of existing dwellings in the UK are exposed noise levels that may preclude reliance on opening windows to mitigate overheating in future dwellings.

Design of an acoustic sensor for fission gas release characterization devoted to JHR environment measurements

Among numerous research projects devoted to the improvement of the nuclear fuel behaviour knowledge, the development of advanced instrumentation for in-pile experiments in Material Testing Reactor is of great interest. In the frame of JHR reactor, new requirements have arisen creating new constraints. An acoustic method was tested with success during a first experiment called REMORA 3 in 2010 and 2011, and the results were used to differentiate helium and fission gas release kinetics under transient operating conditions. This experiment was leading at OSIRIS reactor (CEA Saclay, France). The maximal temperature during the irradiation test was about 150 °C. [1], [2]. We have developed thick film transducers produced by screen-printing process. They offered a wide range of possible application for the development of acoustic sensors and piezoelectric structure for harsh temperature environment measurements [3]. We proposed a screen-printed modified Bismuth Titanate piezoelectric element on alumina substrate allowing acoustic measurements [4] for JHR environment. In this paper we will focus on the mechanical design of the new sensor. This acoustic sensor is composed of an acoustic element for generation and detection of acoustic waves propagating into a cavity filled with gaz. We will detail the choice of piezoelectric materials, the thickness of the different layers, the cavity shapes, the electrical connections, the means of assembly of the different parts. Theoretical and experimental results will be given. All that point will be discussed in terms of acoustic sensor sensitivity versus dimensional constraints, in the case of a high temperature range working.

Effects of Mirror and Metronome Use on Spontaneous Dance Movements

This study investigated effects of mirror and metronome use on spontaneous upper body movements by 10 preprofessional dancers in a motor task in which maximally diverse upper body movement patterns were targeted. Hand and trunk accelerations were digitally recorded utilizing accelerometers and analyzed using polar frequency distributions of the realized acceleration directions and sample entropy of the acceleration time. Acceleration directions were more variably used by the arms than by the torso, particularly so when participants monitored their performance via a mirror. Metronome use hardly affected the predictability of the acceleration time series. The findings underscore the intrinsic limitations that people experience when being asked to move randomly and reveal moderate effects of visual and acoustic constraints on doing so in dance.

Planning Framework for Robot-assisted Blood-Brain Barrier Opening with Focused Ultrasound.

This article presents a method to plan BloodBrain Barrier (BBB) disruption with Focused Ultrasound, under neuronavigated robotic assistance. Robotic and acoustic constraints are defined to estimate brain target accessibility. The relevance of the proposed framework is illustrated in specific brain target examples.

Perceptual fusion of musical notes by native Amazonians suggests universal representations of musical intervals

Music perception is plausibly constrained by universal perceptual mechanisms adapted to natural sounds. Such constraints could arise from our dependence on harmonic frequency spectra for segregating concurrent sounds, but evidence has been circumstantial. We measured the extent to which concurrent musical notes are misperceived as a single sound, testing Westerners as well as native Amazonians with limited exposure to Western music. Both groups were more likely to mistake note combinations related by simple integer ratios as single sounds (‘fusion’). Thus, even with little exposure to Western harmony, acoustic constraints on sound segregation appear to induce perceptual structure on note combinations. However, fusion did not predict aesthetic judgments of intervals in Westerners, or in Amazonians, who were indifferent to consonance/dissonance. The results suggest universal perceptual mechanisms that could help explain cross-cultural regularities in musical systems, but indicate that these mechanisms interact with culture-specific influences to produce musical phenomena such as consonance.

Allometric escape from acoustic constraints is rare for frog calls.

Allometric constraint is a product of natural selection and physical laws, particularly with respect to body size and traits constrained by properties thereof, such as metabolism, longevity, and vocal frequency. Allometric relationships are often conserved across lineages, indicating that physical constraints dictate scaling patterns in deep time, despite substantial genetic and ecological divergence among organisms. In particular, acoustic allometry (sound frequency ~ body size) is conserved across frogs, in defiance of massive variation in both body size and frequency. Here, we ask how many instances of allometric escape have occurred across the frog tree of life using a Bayesian framework that estimates the location, number, and magnitude of shifts in the adaptive landscape of acoustic allometry. Moreover, we test whether ecology in terms of calling site could affect these relationships. We find that calling site has a major influence on acoustic allometry. Despite this, we identify only four major instances of allometric escape, potentially deriving from ecomorphological adaptations to new signal modalities. In these instances of allometric escape, the optima and strength of the scaling relationship are different than expected for most other frog species, representing new adaptive regimes of body size ~ call frequency. Allometric constraints on frog calls are highly conserved and have rarely allowed escape, despite frequent invasions of new adaptive regimes and dramatic ecomorphological divergence. Our results highlight the rare instances in which natural and sexual selection combined can overcome physical constraints on sound production.

P1827 Impact of coronary microcirculatory dysfunction in the impairment of left ventricular deformation parameters by 4D echocardiographic techniques in hypertrophic cardiomyopathy patients

Abstract Background Coronary microvascular dysfunction has been described as an important pathophysiologic feature in hypertrophic cardiomyopathy (HCM). Objective To analyse the impact of coronary microcirculatory dysfunction on left ventricular (LV) deformation parameters obtained by 4D echocardiography in HCM. Methods HCM patients (P) prospectively underwent dedicated transthoracic echocardiogram for microcirculation study. The evaluation of coronary flow velocity reserve (CFVR) was performed in apical three chambers view for the left anterior descending (LAD) artery and in an apical two chambers view for the posterior descending (PD) artery. Diastolic coronary flow velocity (CFV) was measured at basal conditions and during hyperaemia, induced with adenosine perfusion (0.14 mg/kg/min intravenously, during 2 minutes). Absolute CFVR was calculated as the ratio of hyperaemic to basal peak diastolic flow velocities. By 4D TTE (GE E95 equipment) LV global longitudinal strain (GLS), global circumferential stain, global radial strain, area strain, twist and torsion were analysed. Results 23 P were enrolled (57% male, mean age 57.9 ± 13.7 years). Asymmetric septal hypertrophy was verified in 70% of patients, with maximal wall thickness of 21.6 ± 4.3mm. Obstructive HCM was documented in 35% of patients. CFV was successfully measured in the LAD in all patients, but only in 70% of patients in the PD due to technical issues related to poor acoustic window and anatomical constraints. 78% of P (n = 18) presented CFVR <2, denoting microcirculatory dysfunction. Relative CFVR (CFVR LAD / CFVR PD) was ≥1 in 43% of P. At baseline conditions, 4D GLS < -8% was associated with lower LAD flow (34.3 ± 8.3 vs 42.7 ± 9.7cm/s; p = 0.037), trend to lower PD flow (35.3 ± 17.8 vs 49.9 ±18.4 cm/s; p = 0.066). 4D GLS < -8% P presented higher CFVR PD (2.0 ± 0.8 vs 1.1 ± 0.2; p = 0.009), with no significant difference in CFVR LAD. Global circumferential stain <-13% seemed to be associated with lower basal CFV LAD (32.5 ± 8.8 vs 40.4 ± 9.5 cm/s; p = 0.089) and PD (29.8 ± 9.0 vs 45.6 ± 17.4 cm/s; p = 0.054). P with better global circumferential stain (<-13%) presented higher CFVR PD (2.3 ± 0.7 vs 1.4 ± 0.7; p = 0.005), as well as P with an area strain <-18% (CFVR PD 2.0 ± 0.8 vs 1.4 ± 0.8; p = 0.038). P with LV twist >4deg presented higher CFV PD at baseline (49.6 ± 16.5 vs 33,8 ± 12.9 cm/s; p = 0.039) and during hyperemia (68.0 ± 12.2 vs 52.9 ± 12.1cm/s; p = 0.032). Conclusion HCM P with greater impairment in LV deformation parameters by 4D echocardiography presented increased basal diastolic CFV, which can be explained by increased coronary vascular resistance and a higher oxygen demand at baseline conditions. Worse LV performance was also associated with decreased CFVR, mainly in PD.

Large-eddy simulation of an air-assisted liquid jet under a high-frequency transverse acoustic forcing

The present contribution falls in the scope of high-frequency combustion instabilities occurring in liquid rocket engines. Under subcritical operating conditions, numerical simulations have to render the effects of acoustic waves on the atomisation of liquid jets since these may impact the stability of the engine. Therefore, the present contribution aims at evaluating the ability of a particular numerical strategy adapted to the simulation of two-phase flows to render these interaction mechanisms. The selected strategy is based on the coupling between a diffuse interface method for the simulation of large liquid structures, and a kinetic-based Eulerian model for the description of droplets. The numerical simulation of an air-assisted liquid jet submitted to a transverse acoustic modulation is performed. The flattening of the liquid core under acoustic constraints is retrieved and induces an intensification of its stripping. In addition, thanks to appropriate coupling source terms, the modification of the spray shape as well as periodic oscillations of droplets are retrieved. The numerical strategy is thus proved to be adapted to deal with atomised liquid jets under transverse acoustic modulation and can be used for future numerical studies of high-frequency combustion instabilities.

Data Driven Product Portfolio Analysis of Electric Motors Based on Product Platforms Using Knowledge-Based Systems

AbstractFor a company it is necessary to know, which products can be configured using carry-over-parts or the same technology. This can become quite relevant in the context of automobile electrification, where complex mechatronic systems are used. Consisting of various mechanical components, these systems perform the required function while being actuated by electronically controlled motors. To solve this, a novel mechanism for data driven portfolio analysis based on product platforms using knowledge-based systems is proposed in this paper. Further, the mechanism is tested by applying it to an electrical motors' case study. Using this method, all possible combinations of a product platform are calculated and finally displayed in different product portfolios. Additionally, all the non-feasible motor designs are removed from the solutions portfolio using the acquired knowledge base and performing design checks. The latter are employed for penalising and eliminating from the pareto-front of the designs, which violate the thermal, mechanical and acoustic constraints. The generated product portfolio can be used further to expand the systems engineering collaboration and support decision-making.

How the environment shapes animal signals: a test of the acoustic adaptation hypothesis in frogs.

Long-distance acoustic signals are widely used in animal communication systems and, in many cases, are essential for reproduction. The acoustic adaptation hypothesis (AAH) implies that acoustic signals should be selected for further transmission and better content integrity under the acoustic constraints of the habitat in which they are produced. In this study, we test predictions derived from the AAH in frogs. Specifically, we focus on the difference between torrent frogs and frogs calling in less noisy habitats. Torrents produce sounds that can mask frog vocalizations and constitute a major acoustic constraint on call evolution. We combine data collected in the field, material from scientific collections and the literature for a total of 79 primarily Asian species, of the families Ranidae, Rhacophoridae, Dicroglossidae and Microhylidae. Using phylogenetic comparative methods and including morphological and environmental potential confounding factors, we investigate putatively adaptive call features in torrent frogs. We use broad habitat categories as well as fine-scale habitat measurements and test their correlation with six call characteristics. We find mixed support for the AAH. Spectral features of torrent frog calls are different from those of frogs calling in other habitats and are related to ambient noise levels, as predicted by the AAH. However, temporal call features do not seem to be shaped by the frogs' calling habitats. Our results underline both the complexity of call evolution and the need to consider multiple factors when investigating this issue.

Acoustic Constraints and Musical Consequences: Exploring Composers' Use of Cues for Musical Emotion.

Emotional communication in music is based in part on the use of pitch and timing, two cues effective in emotional speech. Corpus analyses of natural speech illustrate that happy utterances tend to be higher and faster than sad. Although manipulations altering melodies show that passages changed to be higher and faster sound happier, corpus analyses of unaltered music paralleling those of natural speech have proven challenging. This partly reflects the importance of modality (i.e., major/minor), a powerful musical cue whose use is decidedly imbalanced in Western music. This imbalance poses challenges for creating musical corpora analogous to existing speech corpora for purposes of analyzing emotion. However, a novel examination of music by Bach and Chopin balanced in modality illustrates that, consistent with predictions from speech, their major key (nominally “happy”) pieces are approximately a major second higher and 29% faster than their minor key pieces (Poon and Schutz, 2015). Although this provides useful evidence for parallels in use of emotional cues between these domains, it raises questions about how composers “trade off” cue differentiation in music, suggesting interesting new potential research directions. This Focused Review places those results in a broader context, highlighting their connections with previous work on the natural use of cues for musical emotion. Together, these observational findings based on unaltered music—widely recognized for its artistic significance—complement previous experimental work systematically manipulating specific parameters. In doing so, they also provide a useful musical counterpart to fruitful studies of the acoustic cues for emotion found in natural speech.

Even weirder than the real thing—Gated reverb history and aesthetics

Sound presented via loudspeaker may take advantage of signal processing to create sounds not possible in an all-acoustic production chain. Breaking free of the acoustic constraints for music-making in the concert hall to take advantage of an analog, digital and electro-acoustic production chain has been a major attraction for many popular recording artists. New aesthetics evolved. Among the most absurd sonic concoctions to come from this, gated reverb is part discovery, and part invention, motivated by misunderstandings, and driven by plain old rock and roll rebellion. This paper tours the development of gated reverb, with audio illustrations, and makes the case for its continued use today.

A global modelling approach of natural ventilation with acoustic and daylighting constraints

ABSTRACTNatural ventilation helps to cool buildings in summer without energy consumption, but its application may be restricted by acoustic and glare constraints. Here, a modelling approach integrating different physical aspects was developed and connected to TRNSYS. Different control strategies of glazed openings were defined and simulations were performed with an office room and a detached family house. We find the natural ventilation potential is largely reduced due to acoustic and visual comfort constraints. An acoustic shutter, which facilitates more frequent window opening during occupancy by decreasing outdoor noise transmission, was equally studied in detail with the help of this modelling approach. The acoustic shutter improves the acoustic and thermal comforts for intelligent control strategy and is an attractive solution to enhance the natural ventilation potential under a moderate noisy environment.

Auditory Lexical Decision and Repetition in Children: Effects of Acoustic and Lexical Constraints.

The objective of this study was to identify factors that may detract from children's ability to identify words they do and do not know. Factors investigated were acoustic constraints stemming from the presence of hearing loss (HL) or an acoustic competitor, and lexical constraints due to an impoverished or cluttered vocabulary. Eleven children with normal hearing (NH) and 11 children with bilateral, mild to moderately severe sensorineural HL were asked to categorize and repeat two-syllable real and nonsense words. Stimuli were amplified and frequency shaped for each child with HL and presented randomly at a level consistent with average conversational speech (65 dB SPL). About half of the children in each group listened in quiet while the other half listened in multitalker babble. In addition to overall performance, responses were judged based on the word category chosen by the child (real or nonsense), the category of the word produced by the child as judged by an examiner (real or nonsense), and the accuracy of the verbal response compared with the stimulus. From these judgments, 10 discrete types of errors were identified. Analyses were conducted for three different combinations of the 10 error categories to best characterize the effects of acoustic and lexical constraints. Performance was highest for real words presented in quiet and poorest for nonsense words presented in multitalker babble. Also, the performance of the children with HL was poorer than that of the children with NH. Error analyses revealed strong effects of acoustic constraints on performance but few effects of lexical constraints. The two most frequently occurring errors were the same for both children with NH and the children with HL and entailed the misperception of nonsense words and the mistaking of nonsense words for real words. However, while both groups of children exhibited these errors in multitalker babble, the children with HL demonstrated these errors in quiet as well. These results suggest that children's interactions with real and nonsense words are significantly constrained when the acoustic signal is degraded by HL and/or an acoustic competitor. The children's tendency to repair unknown words into real words in the presence of acoustic interference may be beneficial when perceiving familiar speech, but could also be detrimental if that tendency causes them to miss opportunities to learn new words.

Environmental constraints drive the partitioning of the soundscape in fishes

The underwater environment is more and more being depicted as particularly noisy, and the inventory of calling fishes is continuously increasing. However, it currently remains unknown how species share the soundscape and are able to communicate without misinterpreting the messages. Different mechanisms of interference avoidance have been documented in birds, mammals, and frogs, but little is known about interference avoidance in fishes. How fish thus partition the soundscape underwater remains unknown, as acoustic communication and its organization have never been studied at the level of fish communities. In this study, passive acoustic recordings were used to inventory sounds produced in a fish community (120 m depth) in an attempt to understand how different species partition the acoustic environment. We uncovered an important diversity of fish sounds, and 16 of the 37 different sounds recorded were sufficiently abundant to use in a quantitative analysis. We show that sonic activity allows a clear distinction between a diurnal and a nocturnal group of fishes. Moreover, frequencies of signals made during the day overlap, whereas there is a clear distinction between the different representatives of the nocturnal callers because of a lack of overlap in sound frequency. This first demonstration, to our knowledge, of interference avoidance in a fish community can be understood by the way sounds are used. In diurnal species, sounds are mostly used to support visual display, whereas nocturnal species are generally deprived of visual cues, resulting in acoustic constraints being more important.

Using genetic algorithms to improve the thermodynamic efficiency of gas turbines designed by traditional methods

A method for optimizing the thermodynamic efficiency of aeronautical gas turbines designed by classical methods is presented. This method is based in the transformation of the original constrained optimization problem into a new constrained free optimization problem which is solved by a genetic algorithm. Basically, a set of geometric, aerodynamic and acoustic noise constraints must be fulfilled during the optimization process. As a case study, the thermodynamic efficiency of an already optimized by traditional methods real aeronautical low pressure turbine design of 13 rows has been successfully improved, increasing the turbine efficiency by 0.047% and reducing the total number of airfoils by 1.61%. In addition, experimental evidence of a strong correlation between the total number of airfoils and the turbine efficiency has been observed. This result would allow us to use the total number of airfoils as a cheap substitute of the turbine efficiency for a coarse optimization at the first design steps.

Dynamic adjustment of biosonar intensity to habitat clutter in the bat Macrophyllum macrophyllum (Phyllostomidae)

Echolocating bats adjust the time–frequency structure such as sweep rate and pulse interval of their sonar calls when they move from open space to vegetation-dense environments. Emitted call intensity is equally important for echolocation, but adjustment of signal intensity to different habitats has never been systematically studied in any bat species. To address this question, we recorded sonar calls of the Neotropical trawling insectivorous bat Macrophyllum macrophyllum (Phyllostomidae) at three sites with different obstacle densities (clutter). We found a clear correlation between emitted intensity and degree of clutter, with intensity proportional to decreasing clutter. In highly cluttered, semicluttered, and open spaces, M. macrophyllum emitted calls with mean source levels (sound pressure level (SPL) 10 cm from the bat’s mouth) of 100, 105, and 111 dB SPL root mean square (rms), respectively. To our knowledge, this is the first documentation of dynamic intensity adjustments in bats. Phyllostomid bats were previously considered silent, but the 111-dB SPL rms emitted by free-ranging M. macrophyllum in open space is comparable to output in aerial insectivorous bats from other families. Our results suggest that the acoustic constraints of habitats are better predictors of call intensity than phylogeny and therefore likely to be major drivers shaping the sonar system of bats in the course of evolution.

Distinctive features: Phonological underspecification in representation and processing

Phonological variation of any sort (determined by speech styles, phrasing, or morphophonological rules) affecting the shapes of words and morphemes are a matter of concern for theories of speech perception and language comprehension. To come to grips with parsing the speech stream, accessing the lexicon and ultimately recognizing words, both representational as well as processing issues must be considered. The central questions in the research presented here are: W hat is represented in the mental lexicon? H ow is it represented? H ow is the speech signal parsed and information mapped onto the mental lexicon? In this paper we will address four issues within the framework of our Featurally Underspecified Lexicon model (FUL): (a) our assumptions concerning distinctive feature organization defined by phonological, perceptual and acoustic constraints; (b) specification of features in the mental lexicon (based on universal and language specific requirements); (c) extracting distinctive features from the signal; (d) mapping features from the signal to the lexicon. We claim that phonological features are extracted from the variable acoustic signal based on broad acoustic properties. A three-way matching algorithm maps these features onto highly abstract phonological mental representations. We provide evidence from synchronic phonological analyses, language change, psycholinguistic and neurolinguistic data.