bluuebunny/crossref_metadata_2025 huggingface dataset:
Signal Quality Analysis for Long-Term ECG Monitoring Using a Health Patch in Cardiac Patients
Authors: Campero Jurado Israel , Lorato Ilde , Morales John , Fruytier Lonneke , Stuart Shavini , Panditha Pradeep , Janssen Daan M. , Rossetti Nicolò , Uzunbajakava Natallia , Serban Irina Bianca , Rikken Lars , de Kok Margreet , Vanschoren Joaquin , Brombacher Aarnout
Published: February 2023

Cardiovascular diseases (CVD) represent a serious health problem worldwide, of which atrial fibrillation (AF) is one of the most common conditions. Early and timely diagnosis of CVD is essential for successful treatment. When implemented in the healthcare system this can ease the existing socio-economic burden on health institutions and government. Therefore, developing technologies and tools to diagnose CVD in a timely way and detect AF is an important research topic. ECG monitoring patches allowing ambulatory patient monitoring over several days represent a novel technology, while we witness a significant proliferation of ECG monitoring patches on the market and in the research labs, their performance over a long period of time is not fully characterized. This paper analyzes the signal quality of ECG signals obtained using a single-lead ECG patch featuring self-adhesive dry electrode technology collected from six cardiac patients for 5 days. In particular, we provide insights into signal quality degradation over time, while changes in the average ECG quality per day were present, these changes were not statistically significant. It was observed that the quality was higher during the nights, confirming the link with motion artifacts. These results can improve CVD diagnosis and AF detection in real-world scenarios.
Crip Time and Radical Care in/as Artful Politics
Authors: Chazan May
Published: February 2023

This article brings together critical disability scholarship and personal narrative, sharing the author’s pandemic story of disruption, caregiving, grief, burnout, cancer, and post-operative fatigue. It offers critical reflection on the limits of the neoliberal academy and possibilities for practicing liberatory politics within it, posing two central questions: What does it mean to crip time and centre care as an arts-based researcher? What might a commitment to honouring crip time based on radical care do for the author and their scholarship, and for others aspiring to conduct reworlding research? This analysis suggests that while committing to “slow scholarship” is a form of resistance to ableist capitalist and colonial pressures within the academy, slowness alone does not sufficiently crip research processes. Crip time, by contrast, involves multiply enfolded temporalities imposed upon (and reclaimed by) many researchers, particularly those living with disabilities and/or chronic illness. The article concludes that researchers can commit to recognizing crip time, valuing it, and caring for those living through it, including themselves, not only/necessarily by slowing down. Indeed, they can also carry out this work by actively imagining the crip futures they are striving to make along any/all trajectories and temporalities. This means simultaneously transforming academic institutions, refusing internalized pressures, reclaiming interdependence, and valuing all care work in whatever time it takes.
Space-Time Properties of Extreme RN Black Holes in Static Triangular Distribution
Authors: Shen Gangqi , Wang Yu , Lü Houjun
Published: February 2023

We studied the space-time properties of the triangular symmetric black hole in the case of extreme RN black hole. Because the neutral test particle is only affected by space-time in the curved space-time, we chose the triangular symmetric black hole as the model with which to study the motion of the test particle in this case. The curvature tensor and curvature scalar were calculated by giving the metric and the Christoffel Symbol, and then the kinematics equation of the test particle was obtained and analyzed by using these quantities. Then we analyzed the relationship between the coordinate distance and the inherent distance, the relationship between the coordinate time and the inherent time, the inherent velocity and the coordinate velocity of light, and then verified the correctness of general relativity. Next, the one-dimensional effective potential and two-dimensional effective potential of the system under different separation distances were analyzed. Finally, we analyzed and explored the innermost stable circular orbit, calculated all the Lagrange points under this model, and expounded some applications of circular orbit in astrophysics.
Fishing Cat Scats as a Biomonitoring Tool for Toxic Heavy Metal Contamination in Aquatic Ecosystems
Authors: Harika Thirupati , Al-Ghanim Khalid , Riaz Mian , Krishnappa Kaliyamoorthy , Pandiyan Jeganathan , Govindarajan Marimuthu
Published: February 2023

Mangrove forest is one of the productive ecosystems that provide essential habitats for various fauna as breeding and feeding drives. However, heavy metal pollution in the mangrove forest has led to severe health problems for several aquatic species. Biomonitoring of metals using a nondestructive method is an emerging technique. Scats of the fishing cat (Prionailurus viverrinus) were collected from five locations in the Godavari estuary mangrove habitats, Coringa Wildlife Sanctuary, Andhra Pradesh, India, to determine the level of various metals. An opportunistic method was applied to collect scats in the mangrove forest. Six scat samples were collected from each of the sampling sites. The following prey species, such as crabs, fishes, birds, rodents, plants, plastics, and unidentifiable prey matters, were found in the scats. Select metals, such as chromium (Cr), copper (Cu), and lead (Pb) were analyzed from the scats of the fishing cat since they intensively influence the physiology and behavior of top predators. The concentration of Cu in fishing cat scats was higher than the other two metals assessed. Metals showed statistically substantial variation across locations (p < 0.05). According to the current study, heavy metals may significantly threaten the fishing cat in the Coringa Wildlife Sanctuary. The fishing cat is a vulnerable species in accordance with the ICUN categories. Due to pollution and other human pressures, the fishing cat may soon be categorized as a threatened or endangered species; the research advises that authorities should prioritize the protection of the vulnerable species of the fishing cat from the Coringa Wildlife Sanctuary, Andhra Pradesh, India.
A botanical name for a well-known Hylotelephium (Crassulaceae) hybrid
Authors: Shaw Julian M. H. , Stephenson Ray
Published: February 2023

A widespread hybrid of Hylotelephium spectabile (Boreau) H.Ohba × H. telephium subsp. maximum (L.) H.Ohba (Crassulaceae), is commonly referred to by a cultivar name, ‘Herbstfreude’. A binomial, Hylotelephium × mottramianum J.M.H. Shaw & R. Stephenson is provided for the nothospecies.
Can acoustic design accommodate aural diversity?
Authors: Davies Bill
Published: February 2023

Up to now, the acoustic design of almost everything has assumed a typical listener with "normal" hearing. This includes the physical environment (homes, workplaces, public space), products that make sound (transport, appliances, loudspeakers), and systems for broadcast and
reproduction (TV, radio, games). But at least one in five people in the world has atypical hearing. They are either narrowly medicalised (e.g., hearing aids) or mostly ignored (e.g., noise sensitivity). As the global population ages this proportion will increase. Aural diversity is a way of
reconceptualising human experience of sound that emphasises the broad and semi-continuous distribution of differences that exist in detecting, processing and responding to sound. This paper explores whether acoustic design could adapt to incorporate the concept of aural diversity and what
might be gained in doing so. The literature is reviewed to see how several different kinds of aural divergence are currently characterised and to identify some other auditory differences that are under-researched. A conceptual framework is proposed in which a single "normal" hearing
model could be replaced with a hearing distribution or a multi-dimensional space of aural experience.
Virtual work experience in acoustics
Authors: Muirhead Matthew , Wills Vicky
Published: February 2023

The Institute of Acoustics is in the process of organising a virtual work experience for up to 1000 GCSE and A-Level students. Unlike traditional workplace work experience, the virtual environment will provide an overview of the acoustics industry, an opportunity to engage with a large
number of students from anywhere in the UK and a window to show young people the huge range of careers in acoustics. Through this initiative it is hoped that we will be able to inspire a pipeline of future acousticians. The work experience has been designed to run over two weeks, for 1 hour
a day, and will include engaging content like videos, games, activities and live webinars. The modules will cover careers in consultancy, research, local authority, medical science, music and technology, and will cover the range of career pathways into our industry. This paper outlines the
collaborative approach taken in creating and curating the virtual work experience programme. It gives an insight into structuring an inclusive and exciting experience for students and discusses the lessons learned from attempting to successfully showcase such an inherently diverse subject.
Serial recall performance under different room acoustic conditions
Authors: Selzer Jan , Schelle Florian , Fiebig André
Published: February 2023

In office workplaces high demands on the concentration of employees are set. This is contrasted by the effect of irrelevant speech, which has been shown to decrease working memory performance. The presented survey investigates the impact of different room acoustic conditions on the
irrelevant speech effect. To address this question, the decrease of performance was investigated by a serial recall test using a within-subject design. Six stimuli were used for the experiment: silence as reference, pink noise, two speech signals with different degrees of fluctuation strength,
each presented in room acoustic conditions with long and without reverberation. Each stimulus is used in twelve trials. One trial consisted of the representation phase of nine digits, sequentially presented in random order and the recall phase. Furthermore, different test designs were used.
In the first design the playback of the stimulus was continuing during twelve trials. In the second design each trial had a randomised stimulus playback. In addition, the annoyance was assessed, and a closing interview conducted. The results of the study with 44 participants are presented
and discussed in this contribution. Overall, a significant decrease in performance is observed in the speech conditions compared to the reference condition.
Spatial audio for interactive hearing research
Authors: Kuntz Matthieu , Seeber Bernhard U.
Published: February 2023

The use of sound field synthesis for hearing research has gained popularity due to the ability to auralize a wide range of sound scenes in a controlled and reproducible way. We are interested in reproducing acoustic environments for interactive hearing research, allowing participants
to move freely over an extended area in the reproduced sound field. While the physically accurate sound field reproduction using sound field synthesis is limited to the sweet spot, it is unclear how different perceptual measures vary across the reproduction area and how suitable sound field
synthesis is to evaluate them. To investigate the viability of listening experiments and provide a database for modelling approaches, measurements of binaural cues were carried out in the Simulated Open Field Environment loudspeaker array. Results show that the binaural cues are reproduced
well close to the center, but exhibit more variance than in the corresponding free field case. Off center, lower interaural coherence is observed, which can affect binaural unmasking and speech intelligibility. In this work, we study binaural cues and speech reception thresholds over a wide
area in the loudspeaker array to investigate the feasibility of psychoacoustic experiments involving speech understanding.
An in-plane flexible ring model for the analysis of the free and forced response of a rolling tyre
Authors: Rapino Luca , La Paglia Ivano , Ripamonti Francesco , Corradi Roberto , Baro Simone
Published: February 2023

The increased demand for vibroacoustic comfort as well as regulations on noise and vibration levels have made the NVH (Noise, Vibration, Harshness) performances of a vehicle to become one of the fundamental design criteria. Therefore, predictive models for the analysis of noise and
vibration transmission mechanisms represent interesting tools to support the R&D department of the automotive companies. Focusing the attention on passenger's comfort, the vibrations induced by the tyre/road interaction propagate from the contact area to the hub and finally inside the
cockpit through structure-borne transmission paths. This can be regarded as one of the major contributors to the car cabin interior noise at low frequencies (between 20 and 500 Hz). Simplified models able to interpret the waves propagating inside the tyre structure and influenced by the angular
speed may support the studies in this research field. To this end, an analytical model based on the theory of the flexible ring on elastic foundation has been developed. It allows analysing the tyre dynamics in both static and rolling conditions. Model parameters have been calibrated based
on an Experimental Modal Analysis of the static tyre. The free response of the tyre shows the bifurcation effect at different rolling speeds, while a cleat test simulation has been carried out to investigate the forced response of the tyre.
Application of active noise control based on neural network to vehicle's engine sound
Authors: Lee Donghyeon , Kim Narae , Park Junhong
Published: February 2023

Active noise control(ANC) is a particularly effective system for reducing low-frequency noise to compensate passive noise control. With the recent development of digital signal processor(DSP) performance, ANC has the potential to be developed with various algorithms. Accordingly, several
ANC algorithms using various controlloer such as artificial neural network(ANN) are being proposed. In nonlinear system; at many practical applications, the ANC algorithm using a neural network gets more reduction performance compared to the linear ANC. In this study, the methology proposed
neural network based FxLMS algorithm to reduce noise for non-linear system by predicting time series data for near future. This proposed algorithm is applied to reduce the engine noise of vehicle to construct silent inner environment and verify the performance by below.
Effects of binaural classroom noise scenarios on primary school children's speech perception and listening comprehension
Authors: Leist Larissa , Reimers Carolin , Fremerey Stephan , Fels Janina , Raake Alexander , Klatte Maria
Published: February 2023

When it comes to learning in school, perception of speech and listening comprehension are crucial. The ability to listen effectively under the conditions of background noise and reverberation in a classroom involves the ability to continuously filter out background noise and fill in
missing pieces in the speech communicated by teachers or classmates. A large number of experimental tasks have demonstrated that children's speech perception is significantly more sensitive to unfavorable listening settings than adults' (Buss et al., 2017; Klatte et al. 2013). Despite this,
there are just a few studies that have looked at the impact of real-world classroom noise on children's performance in listening tasks that take into account the demands of school-based education. Rather, the increased listening effort appeared to lower the amount of resources available for
storing and processing information in working memory, as demonstrated by Klatte and colleagues (2010). The goal of this study is to compare children's performance on word identification and listening comprehension tasks in realistic classroom scenarios, which include monaural and binaural
reproductions of complex background noises such as typical classroom sounds and non-native children's speech. Conclusions on the acoustic design of learning environments and the development of speech-in-noise perception in primary school students can be drawn.
Limitations of FxLMS in Feedforward Active Vibration Control of a Nonlinear Two-Degree-of-Freedom System
Authors: Pike Xander , Cheer Jordan
Published: February 2023

Active control systems are often used to surmount the challenges associated with passive noise and vibration control measures to control low frequency disturbances, since they achieve control without the application of large or heavy control treatments. Historically, linear active control
strategies have been used in feedforward control systems to drive the control source to minimise the signal measured at the error sensor. Amongst the various control algorithms available, the Filtered-reference Least Mean Squares (FxLMS) algorithm has become extremely popular in the last few
decades due to its relatively good performance and high level of robustness, as well as simplicity in both design and application. However, when the system under control contains nonlinearities, either in the primary or secondary paths, the performance of the FxLMS algorithm can degrade dramatically.
This paper explores the performance limitations of the FxLMS algorithm when applied to the control of a two degree of freedom mass-spring-damper system with linear and cubic nonlinear stiffness terms. The aim of this study is to improve understanding of and inspire better design of nonlinear
control systems. The statistical uncertainty present in the linear plant model and control filter is discussed, as well as the effect of this on control performance and control effort. The effect of nonlinearity on the maximum convergence parameter of the algorithm is also discussed.
A new Building Regulation for overheating: practical considerations for the acoustic constraints
Authors: Harvie-Clark Jack , Conlan Nick , Dobinson Nicholas , Kazlauciunas Rupert
Published: February 2023

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.
Assessing human activity noise in workspaces using machine learning and numerical models
Authors: De Salvio Domenico , Fratoni Giulia , D'Orazio Dario , Garai Massimo
Published: February 2023

Acoustic comfort of workspace environments is deeply dependent on the balance between indoor background noises. For example, colleagues' speaking might affect task performances by downgrading privacy and productivity. Conversely, HVAC noise can reduce the employee's distraction since
such continuous mechanical noise is detrimental to speech comprehension. Therefore, in the analysis of workspaces' acoustic comfort, different background noise sources identification becomes essential. In this regard, machine learning techniques are resourceful for clustering sound pressure
level patterns among the unlabeled data. A previous work by the authors provided reliable results on separating noise sources via Gaussian Mixture Model and K-means clustering. Nevertheless, such method was applied to a single workspace, and thus it needs further investigation on a wider sample
of environments. For this reason, in the present work long-term monitoring was carried out in various active workspaces extending previous results and confirming the procedure's robustness. Moreover, simulations of the acoustic conditions by summing up the human activity contribution to the
mechanical noise allowed obtaining more reliable speech intelligibility criteria at the workstations. Refining the numerical models' setup through background noise levels obtained through machine learning analysis enhance the assessment of workers' privacy condition in realistic scenarios.
Clustering analyses to assess HVAC noise in real-world conditions
Authors: De Salvio Domenico , D'Orazio Dario , Garai Massimo
Published: February 2023

The assessment of systems' noise during measurements is usually carried out in an empty state of the spaces under study. Long-term monitoring in real-world conditions can provide insights into the performance of systems during the day. Thus, it becomes useful to find methods able to
separate coexisting sound sources in the same space. Clustering techniques can supply the lack of robust methods to perform the segregation. Previous works have shown reliable results about distinguishing human and mechanical noises through sound level meter long-term measurements. Sound pressure
levels (SPLs) were post-processed via Gaussian Mixture Model and K-means clustering with a three-step algorithm. The first step is clustering validation and concerns the assessment of the optimal number of clusters among the candidate models. Then, SPLs were divided into the number of clusters
obtained by the validation. Finally, statistical and metrical features were used to label the sound sources whether mechanical or human, depending on the algorithm that performed the clustering. Carrying out these algorithms during real-time conditions is possible to monitor the actual HVAC
noise providing more accurate analyses. Further studies will focus on broadening the ability to analyze the mechanical noise into its components, such as continuous and discontinuous sources.
Vibrational damping properties of finite microperforated plates
Authors: Gallerand Lucie , Legrand Mathias , Dupont Thomas , Leclaire Philippe
Published: February 2023

Microperforated plates (MPP) are traditionally used to advantageously absorb acoustic waves in sound control technologies. However, less is known concerning the additional structural damping they can induce. The latter is activated through exchanges in the viscous and thermal boundary
layers near the fluid-structure interface of the microperforations. MPPs therefore offer an alternative to, or can be used together with, viscoelastic materials, commonly implemented to damp vibrations at medium and high frequencies. In this work, the structural damping capabilities of MPP
are investigated. To this end, the damping performance of a finite size MPP is explored analytically through an alternative form of the Biot model, classically devoted to porous plates, and considering energy dissipation through viscous friction mechanisms. Analytical results are compared
to experimental measurements of structural damping factors on various MPP samples. The model is validated and confirms the damping effect added by the microperforations in the low frequency range. A sensitivity analysis on the perforation rate and perforation diameter provides a condition
for which additional damping is maximized.
Wicked problems in an aviation noise system
Authors: Runebjörk Isabel , Runebjörk Werner Isabel , Ulfvengren Pernilla
Published: February 2023

There is a growing awareness of impact of aviation noise, such as health an annoyance issues. Community complaints that interfere with airport business has resulted in serious efforts to reduce aviation noise. However, even though improvements have been made, these efforts have not
successfully reduced noise annoyance, in fact, community reactions towards airport operations have increased over time. The project INFRA, was initiated based on a community complaint regarding Arlanda airport, with the objective to develop knowledge of noise annoyance. Based on a broad interview
study, a number of actors and their perspectives have been identified: neighbors, house and land owners, municipals, county board, land and environmental jurisdiction, transportation agency, transport administration, airports, air service providers, environmental protection agency and politicians.
Results show that the aviation system contains opposing perceptions of noise and strategies which induce conflicts and breaches of trust from policies and regulations, all the way down to individual neighbors. An outcome is a set of identified dilemmas representing incompatible worldviews,
and deep disagreement of values. After analysis these are concluded to represent conditions associated with what is called "wicked problem". The study results in an increased understanding and representation of the wicked aviation noise system.
The Vibration Reduction Index of Typical Canadian Cross-laminated Timber Junctions
Authors: Mahn Jeffrey , Müller-Trapet Markus , Cunha Iara
Published: February 2023

In support of the National Building Code of Canada, The National Research Council Canada has published research report RR-335 which describes the results of measurements of the transmission of structure-borne noise through junctions between mass timber elements. The Code only allows
for the use of measured data for the vibration reduction index from the NRC's reports or reports from other research institutes. The Code does not currently allow for the use of empirical data for the calculation of the apparent sound transmission class of mass timber buildings. A lack of
published data for typical mass timber junctions used in Canada can result in the overdesign of buildings or buildings which don't meet the acoustic requirements of the Code. The NRC has embarked on a program to measure the vibration reduction index of a number of mock junctions of typical
junctions used in Canada including junctions between cross-laminated timber floors and lightweight timber framed walls. The new data will aid in the development of empirical models of typical Canadian mass timber constructions.
Effect of urban morphology and greening on noise and air pollution - case studies including disease burden estimates
Authors: Forssén Jens , Haeger-Eugensson Marie , Berghauser Pont Meta , Gustafson Andreas , Achberger Christine , Rosholm Niklas
Published: February 2023

Exposure of both noise and air pollution due to road traffic in urban environments has been calculated and evaluated for multiple cases assuming constant total traffic flow. A model study in an urban setting used 31 cases of building morphologies and traffic concentration. An evaluating
second set was based on a real case of an arterial road transformed into a boulevard. Besides the effect of building morphology, the effects of driving speed, electric vehicles and urban greening were studied. The levels of noise exposure (Lden and Lnight at housing facades) and air pollution
(NO2 and PM10 at sidewalks and yards) were calculated as input to estimating the health impact using DALY (Disability-Adjusted Life Years) per person. Openings in building blocks were shown to impair the noise situation but improve air quality. Nonconflicting positive results were shown for
several solutions including densification by complementing the blocks with towers, transitioning to electric vehicles in combination with reduced vehicle speed, and traffic concentration by locating all local traffic to a single, widened road. Urban greening was shown to improve the noise
situation whereas air quality varied due to the interaction between wind speed, dispersion, and filtering effect of leaves.
An inter-laboratory study to quantify the repeatability, reproducibility, and bias of sound power measurement methods
Authors: Underwood Samuel , Wang Lily
Published: February 2023

An inter-laboratory study across multiple facilities has been completed to quantify the repeatability, reproducibility, and bias of three different sound power measurement methods used in the heating, ventilation, and air-conditioning industry: free field method, diffuse field method,
and intensity method. The sound power levels of a loudspeaker source across one-third octave bands have been measured in each participating laboratory by the test methods preferred in those facilities. Both a broadband signal with decreasing slope of - 5 dB per octave band and the same broadband
signal with four discrete tones at 58, 120, 300, and 600 Hz have been measured in this round robin study. Comparisons of measured sound power levels have been made between methods, between laboratories, and between laboratories using the same method. Repeatability, reproducibility, laboratory
bias, and test method bias are then quantified in accordance with ISO 5725. [Work supported by the Air-Conditioning, Heating, and Refrigeration Institute]
The role of sound emergence for aircraft noise annoyance
Authors: Schreckenberg Dirk , Belke Christin , Wothge Jördis , Guski Rainer
Published: February 2023

The metric emergence relates source-specific sound levels to background noise. The approach of subtracting a residual sound level (total sound level without the level of a specific source) from the total sound level follows the definition of emergence in ISO 1996-1. Using exposure and
survey data of the German NORAH study, the impact of emergence on aircraft noise annoyance was analysed. As total background sound levels were not available, information about source-specific and combined noise levels was used instead. For participants exposed to aircraft and road traffic
noise for the emergence substitute es(air/road), road traffic sound levels for daytime (LAeq,road,day) of the home address of survey participants were subtracted from the combined sound levels of aircraft and road traffic noise (LAeq,air+road,day) with road traffic noise regarded as a proxy
for background noise. Similar, for participants exposed to aircraft and railway noise, LAeq,rail,day were subtracted from LAeq,air+rail,day to obtain es(air/rail). The percentage of people highly annoyed (%HAV) by aircraft was predicted by LAeq,air,day for subgroups with es(air/road) and es(air/rail)
≥ 3 dB and es(air/road) / es(air/rail) < 3 dB. Results: Particularly in low aircraft noise-exposed areas, %HAV is higher for those with higher values of es(air/road) and es(air/rail), respectively.
An investigation of classroom sound levels as a function of class size
Authors: James Adrian
Published: February 2023

It is generally acknowledged that students with special hearing and communication needs should be taught in classrooms with relatively short reverberation times. There has been a great deal of research into the effect of room acoustics on the signal-to-noise ratio experienced by pupils.
There is, however, much less research into the effect of class size on ambient noise levels during lessons, and hence on the signal-to-noise ratio and on absolute sound levels in classrooms. These absolute levels are important because many students with special needs are sensitive to high
noise levels, either for psycho-acoustic reasons or because of the limited dynamic range of cochlear implants and other assistive devices. In his work as an expert witness on acoustics for Special Education Needs and Disabilities Tribunals, the author has measured in-lesson sound levels for
different types of teaching and learning activity in many schools throughout England. He has analysed these to investigate the correlation, when corrected for acoustic factors, between class size and sound levels generated by teachers and pupils, and to consider whether there is a typical
class size at which an effect analogous to the Lombard Effect occurs. From this the author draws conclusions as to the acoustic justification for teaching pupils with special hearing and communication needs in smaller classes.
Acoustic monitoring to evaluate the effect of anthropogenic noise within a park
Authors: Zambon Giovanni , Potenza Andrea , Bisceglie Alessandro , Confalonieri Chiara , Canedoli Claudia , Padoa Schioppa Emilio , Benocci Roberto
Published: February 2023

The aim of this paper is to propose the use of passive acoustic monitoring (PAM) as a non-invasive method to investigate the state of communities and ecosystems. PAM operates through the study and characterization of the soundscape of an area. One of the three components of the soundscape
(beside geophony and biophony) is anthrophony, which is the collection of sounds produced by human activities. This kind of sounds can have effects on natural envi-ronments and natural population. In this study, recording instruments and sampling tech-niques have been used to acquire and collect
sound data for long periods (two weeks) in a nat-ural terrestrial ecosystem (Ticino Park) which is affected by road and rail traffic noise. The analysis conducted studied the trends of the eco-acoustic indices belonging to three measure-ment sites to detect the presence of characteristic trends
and to evaluate the influence of the two anthropogenic noise sources at different distances.
Investigation of electric vehicle noise sources on low-noise road surfaces
Authors: Pallas Marie-agnès , Bianchetti Simon , Le Bellec Adrien , Cesbron Julien
Published: February 2023

Electric vehicles (EVs) constitute an increasing share of the vehicle fleet, in particular regarding light vehicles. This ratio may be significantly enhanced in urban areas that favour access to low-emission vehicles. Acknowledged to be quieter than conventional vehicles due to a lower
propulsion noise, EVs feature a comparatively heightened tyre-road noise contribution, further reduction of which can be achieved by selecting appropriate low-noise road surfaces. These factors may result in modified noise source distributions on the vehicles. In the framework of the LIFE
E-VIA project, noise source contributions have been investigated on several light EVs from different segments on a reference ISO road surface, by using a microphone array with dedicated processing. Wide ranges of speeds and driving conditions were considered. In a second step, particular focus
has been placed on the road surfaces, comparing the noise sources of selected EVs either driving on the ISO road surface or on low-noise prototypes optimized for EVs and developed within the project. These are two similar versions of a very thin asphalt concrete 0/6, one containing crumb rubber.
The presentation gives an overview of the EV noise source behaviour and their ranking with regard to the various situations tested in the project.
Wake-adapted ducted propeller for full-scale generic underwater vehicle: parametric study on blade skew for unsteady propeller thrust
Authors: Takahashi Kenshiro , Gargan-Shingles Chris
Published: February 2023

A parametric study of blade skew for unsteady propeller thrust in the wake of an underwater vehicle (BB2) is presented. Unsteady thrust forces transmit via the propeller shaft and produce undesirable noise and vibration, particularly at frequencies corresponding to multiples of the
blade number. The effectiveness of blade skew in reducing noise and vibration has been reported in previous studies, though not for underwater vehicles. The amplitudes of the dominant harmonics of the unsteady propeller thrust are determined using a Fourier series. The balanced skew reduces
the dominant fifth harmonic more significantly than the biased skew at identical total-skew angles. The total-skew angle strongly influences the unsteady propeller thrust magnitude for balanced skew designs, whereas the effect of the maximum forward-skew angle is negligible. Significant fluctuations
in one-blade loads are observed when the blade passes through the downstream wake of the vehicle's sail and casing. Increasing the blade total-skew reduces the blade load fluctuation when the blade approaches the top dead centre position, but has limited influence on the fluctuations when
the blade moves away from this position. The nominal wake distribution at the propeller plane is analysed, and the fifth harmonic is identified as having the largest amplitude. This suggests that an increase in the number of blades would reduce the unsteady propeller thrust of the full-scale
BB2 underwater vehicle.
The impact of China's traffic noise spectrum on the Single-number-quantities (SNQs) evaluation of airborne sound insulation in the new era
Authors: Cai Yangsheng
Published: February 2023

The ISO 717-1 specified the weighted sound reduction index calculation method of airborne sound insulation, also includes two spectrum adaptation terms C and Ctr, to take into account different spectra of environmental and living noises. The reference spectrum for Ctr is A-weighted
urban traffic noise, and it is meant for noise sources such as traffic noise (urban road traffic, railway traffic at low speeds, propeller driven aircraft), disco music, and factory emission noise (low and medium frequency noise emissions).It should be noted that the spectra Ctr applied in
ISO 717-1 was adopted from the Nordtest Method NT ACOU 061 (Nordtest, 1987).The means of transportation are undergoing great changes, and the characteristics of traffic noises are also changing significantly. Therefore, in order to better resolve the disputes caused by sound insulation and
traffic noise in China, it is necessary to explore whether the existing evaluation standards are still applicable to various types of traffic noise. In this paper, the urban traffic noises in China have been measured and analyzed, a new spectrum adaptation terms for airborne sound insulation
evaluation was established, and applied to the calculation of sound insulation of several common building components, and its applicability was discussed.
Amplitude-decorrelation avoiding spectral artifacts of sound field synthesis in the anechoic chamber or free sound field
Authors: Zotter Franz , Frank Matthias , Müller Gregor-Johannes , Pinkas Julia , Bayer Oliver
Published: February 2023

Sounds to appear in directions between the loudspeakers will typically activate neighboring loudspeakers with the same signal when spatially rendered. The resulting interference causes frequency- and position-dependent cancellation in the superimposed sound field. While keeping the
number of active loudspeakers uniformly small is often enough to have the few acoustic reflections of a studio environment conceal the unwanted cancellations, they will remain a problem when synthesizing sound fields in the anechoic chamber or free field. Our contribution investigates short
filters for amplitude decorrelation to reduce this problem. The filters supply neighboring loudspeakers via frequency responses that are mutually exclusive and hereby avoid cancellation in the superimposed soundfield. This only works at the expense of requiring a minimum spread to ensure a
spectrally balanced synthesis, i.e., by avoiding to activate single filtered loudspeaker, alone. We present a listening experiment investigating in how far the proposed filter strategy is able to improve the spectral stability within a reasonable range of motion for a seated listener, in the
anechoic chamber. Other thinkable approaches are investigated for comparison.
Study on Sound and Vibration Propagation Caused by External Flow Affecting Interior Noise of Railway Vehicles
Authors: Minorikawa Gaku , Hotta Kousuke , Yamano Noboru
Published: February 2023

Among the aerodynamic noises generated by Railway Vehicles running at high speed, the noise generated by the structure on the roof not only affects the environment along the railroad tracks outside the vehicle, but also propagates inside the vehicle, damaging the comfort of the cabin.
Exterior noise is a phenomenon in which aerodynamic noise generated by the structure propagates, and the source of the noise has been clarified and predicted. On the other hand, interior noise is a combination of flow-induced aerodynamic noise propagating acoustically and structural excitation
caused by pressure fluctuation due to wake vortices around the structure, and these two phenomena have not been investigated quantitatively. In this study, the effects of aerodynamic noise generated by structures in the airflow on the acoustic environment inside and outside the vehicle were
experimentally investigated using a small low-noise wind tunnel from the viewpoint of source and propagation characteristics, and practical modeling of these effects was attempted. In addition, the characteristics of the sound source were investigated in detail by computational aeroacoustic
analysis.
Description of sound absorption by a flat resonator stacking metamaterial with double porosity model
Authors: Brooke Daniel Craig , Umnova Olga , Leclaire Philippe , Dupont Thomas
Published: February 2023

Acoustic metamaterials can be designed by inserting along the path of a sound wave periodically spaced side resonators. An example of efficient design was recently proposed consisting of a perforated stacking of flat annular cavities (the pancake resonator), the perforation allowing
the propagation of sound waves. The pancake resonator is used in absorber mode and the theoretical description of sound absorption can be achieved with the help of the theory of sound propagation in fluid saturated porous media in which two porosities are considered: the main porosity associated
with the perforation and a porosity associated with the flat cavity volumes. Considering a perforation diameter and flat cavity thickness ranging from submillimetric values to a few millimeters allows a wide range of material permeabilities and permeability contrasts between main pore and
stacking of cavities. The relatively small values of diameter and cavity thickness also results in the existence of viscous and thermal boundary layers in the main pore (the perforation) and in the flat cavities. This metamaterial makes simultaneous use of viscothermal losses and periodicity
in order to achieve low frequency sound absorption for an overall small absorber thickness. Experimental results are also presented for the validation of the model.
Traffic noise and children's health: New insights from a machine learning algorithm?
Authors: Spilski Jan , Giehl Christoph , Boshuizen Hendriek , Wong Albert , Bergström Kirstin , Lachmann Thomas , Klatte Maria
Published: February 2023

Studies on the influence of traffic noise on children's health are usually very comprehensive and collect data on a large number of measured variables in comparatively large samples. In the NORAH Study, for example, almost 700 variables have been considered including more than 100 variables
related to traffic noise. With a theory-based approach, the statistical evaluation of that data focused on a limited number of variables to be included in the regression models as predictors, mediators, moderators, or confounders. In contrast, machine learning (ML) methods are able to consider
the complete scope of variables in an analysis. Random forest models are one type of ML methods for dealing with possible multicollinearity of predictors or nonlinear relationships. Although these methods can offer advantages, they have hardly been used in relation to traffic noise and children's
health. In the EU project EqualLife, random forest models are computed in order to obtain information on the significance of individual exposomes (e.g., traffic noise) for children's health. In the present paper, we compare the results of a regression model and a random forest model using
the NORAH Study as an example. Possible advantages and disadvantages of the methods are discussed.
Structural design optimization of a high-speed rotor system for mechanical vibration mitigation
Authors: Ran Liaoyuan , Halim Dunant , Ket Thein Chung , Galea Michael
Published: February 2023

This work proposes a design optimization approach for a high-speed rotor system, commonly used in a wide range of industrial applications, in order to address the issue with the flexural flexibility of a rotor system which can cause significant vibration and noise problems due to shaft
whirl. For this purpose, the numerical modeling of a flexible rotor system was used to carry out the optimization process considering the effects of the mass and transverse natural frequency to the optimized design. Torque and geometrical sizing were also incorporated as the constraints in
the optimization. The rotor system was modeled as a multi-disc Jeffcott rotor system that allows a rapid design optimization process. A case study on a high-speed rotor was carried out to demonstrate the effectiveness of the developed optimization approach, yielding the reduction of the rotor
mass by at least 45.6%, while the fundamental transverse natural frequency has been increased by 2.91% as the result.
Acousto-optic sensing for near-field acoustic holography
Authors: Verburg Samuel A. , Fernandez-Grance Efren , Williams Earl G.
Published: February 2023

Near-field acoustic holography (NAH) is a very powerful and widely used technique for the study of complex acoustic radiators. NAH enables to quickly understand how a complex source radiates into the medium. The technique is particularly suitable at low frequencies. At high frequencies,
a dense transducer interspacing is required, and the measurement microphones can disturb the studied sound field when their size is comparable to the acoustic wavelength. In this study we examine the use of acousto-optic sensing in NAH. Acousto-optic sensing uses light beams as the sensing
element, making it possible to acquire remote and non-invasive measurements without introducing extraneous objects in the vicinity of the source. The pressure, particle velocity and intensity fields, as well as the sound power radiated by a complex source, are determined from measurements
in the near-field with an optical interferometer. The presented results demonstrate the potential of optical sensing to non-intrusively characterize sound fields, particularly at high frequencies.
Clustering the residential noise in apartment house based on spectral and temporal analysis
Authors: Kim Jeonghun , Lee Songmi , Kim Suhong , Song Eunsung , Kim Dokyeong , Eom Chunwon , Ryu Jongkwan
Published: February 2023

This study aimed to investigate how the residential noises cluster based on spectral and temporal characteristics of the noises in apartment houses. The type of noise was floor impact, air-borne, plumbing, transmitted outdoor unit of air-conditioner, traffic (road, rail, and air-craft
noise), and construction noise. Duration of sound was edited to 5 s and sound pressure level was adjusted to be equal to be 50 dBA. K-means clustering analysis was performed to classify various sound sources, and the elbow method was used to confirm the number of clusters. As a result, residential
noise sources were classified into twelves clusters according to spectral and temporal characteristics and difference in psychoacoustic parameters between clusters was also found. In addition, perceptual aspect of each cluster was investigated through sematic differential test.