bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of the replacement of distressed pavements by low noise pavements - a case study in Portugal
Authors: RAMOS Maria Inês , BRAGA Margarida , FERNANDES Luis , FREITAS Elisabete , RATO Maria João , DOMINGUES Rosa Daniela
Published: October 2024

BRISA is employing efforts to evaluate the pavement influence as a factor of source noise reduction, while studying forms of adjusting the applicability of the CNOSSOS noise prediction method to the reality of the concession road network, in order to comply with European directives
about Environmental Noise evaluation and management. This Project evaluates the environmental noise effects of replacing a wearing course of Porous and Betuminous Asphalt at end-of-life for a course of SMA12 and new Betuminous Asphalt. Two methodologies were applied to evaluate Tire-Pavement
noise, (i) through Statistical Pass-By and (ii) Close Proximity methods. Using these methodologies, it was possible to evaluate the effect of the intervention and the evolution of the noise in the first few months of the exploration of the layers and to monitor noise performance of the pavements
during its entire lifetime. Brisa is challenged to have better pavements knowledge to extend CNOSSOS pavement library and update noise models.
Soundscape and indoor air quality in naturally ventilated educational environments: a multi-domain study
Authors: PELLEGATTI Matteo , VISENTIN Chiara , TORRESIN Simone , BABICH Francesco , PRODI Nicola
Published: October 2024

In this study, indoor air quality (IAQ) and acoustics were jointly analysed to determine their i) combined effect on students' performance in a math task, and ii) cross-modal effect on soundscape perception. 192 students (12 to 14 years) took part in a laboratory experiment. Students
were separated into two classroom-like chambers with different IAQ conditions: a CO2 concentration of 800 and 2000 ppm, respectively. The participants were asked to solve calculations and answer a soundscape questionnaire in three listening conditions: quiet, a natural scenario with birdsongs,
and one scenario with children's playground activity sounds. In the latter two conditions, the sounds were played back through headphones at a level of 47 dBA. Results show that students had faster response times in the math task in quiet compared to the listening condition with children's
activity sounds, while maintaining a similar task accuracy. No effect of the IAQ conditions and natural sounds was found on the task performance. No cross-modal effect of CO2 concentration on soundscape perception was detected. Regarding soundscape assessments, playground activity was rated
as the most annoying listening condition, while listening to birdsongs was the most pleasant one, despite its noise level exceeding the quiet condition.
Perceptual evaluation of sound synthesis of wind turbine noise
Authors: MEUNIER Sabine , EL SAWAF Ossen , MARQUIS-FAVRE Catherine , COUZON Gauthier , STRAUSS Nicolas , COTTé Benjamin , MASCARENHAS David , CHATRON Jacques
Published: October 2024

This study brings together several laboratories with the aim of assessing the health effects of "audible" noise (> 20 Hz) and infrasound (< 20 Hz) emitted by wind turbines. To study loudness and annoyance due to this noise, perceptual tests are planned at the LMA, where
a restitution cabin has been developed, specifically designed to diffuse very low frequencies and infrasound. As recording wind turbine noise is only possible at low wind speeds for a good quality sound reproduction, it would be interesting to be able to use sound synthesis of wind turbine
noise. From sounds recorded in a wind farm for different meteorological conditions, the corresponding sounds have been synthesized. A physical model synthesis was performed, based on an extended-source aeroacoustic model taking into account propagation over flat ground. Dissimilarity tests
including recorded and synthesized sounds enabled a 2D perceptual space to be built. Synthesized and the corresponding recorded sounds are closed together in the perceptual space, but some differences can be perceived, mainly due to difference in amplitude of fluctuation and spectral balance.
The analysis of the perceptual space opens up interesting prospects for improving the sound synthesis and its use for future perceptual tests.
Impact sound insulation performance of floor coverings in a heavyweight reference floor with a floating floor
Authors: KIM Yong Hee , YEON Jun-Oh , MOON Soon-Seong , YUN Chang-Yeon , PARK Ji-Su
Published: October 2024

This study investigates the impact sound reduction performance of floor coverings used on the heavyweight standard floor of a floating floor structure in comparison with bare slab testbeds through on-site experiments. The laboratory performance evaluation of floor coverings designates
only a bare slab between 100 mm and 160 mm as the heavyweight reference floor according to Annex C in ISO 10140-5. However, the recent expansion of over-floor heating systems has led to an increased need for understanding the impact sound reduction performance of floor coverings on floating
floors, to enhance occupants' thermal comfort. In this study, it was measured the heavyweight and lightweight floor impact sound reduction levels of various floor covering test specimens in testbeds with different thicknesses of bare slabs and actual apartment houses with floating floors applied.
The reduction rate for each frequency band was determined before and after installing floor coverings including single number quantity in accordance with ISO 717-2. Additionally, the impact of heavyweight reference floor conditions on quantifying the sound performance of floor coverings was
discussed.
Instrumentation techniques for the measurement of gunfire (Part 3)
Authors: NASH Anthony , MURPHY William
Published: October 2024

This paper is the third in a series concerning near-field measurement of sound pressure from small arms gunfire. It has been long established that exposure to gunfire events can lead to permanent threshold shift for an unprotected shooter. Close to a shooter's ear, the peak sound pressure
level from a rifle or pistol can be 155-to-160 decibels with a pulse rise time on the order of ten microseconds. The U.S. Department of Defense has considered two approaches for assessing exposure limits from small arms gunfire - one involves the unweighted peak sound pressure and the other
a series of A-weighted sound exposure events integrated to obtain an equivalent eight-hour dose. This dose is then compared to hearing damage risk criteria established for continuous noise signals. The first approach places great demands on the measurement system since the necessary bandwidth
extends well into the ultrasonic range, thereby requiring fast slewing from the amplifiers combined with high sampling rates from the digitizer. The second approach requires the A-weighting filter to have specified time and frequency domain properties in the ultrasonic region. The paper discusses
some laboratory experiments using actual gunfire signals to simulate the outcome from both approaches.
Reducing discomfort by integrating unpleasant environmental sounds with cognitive sound control
Authors: SHIIKU Shota , TAKEUCHI Yugo
Published: October 2024

We respond to unpleasant sounds in our daily lives by blocking out sound environments that we find unpleasant. This may be because of our helplessness in interfering with these sounds. However, blocking limits the range of sound selection. To reduce discomfort from unpleasant sound,
rather than blocking the sound environment, this study aimed to make unpleasant sounds less bothersome by integrating them into music. To achieve this, we expect that participants will intervene in the sound environment where there is unpleasant sound, recognize that the environment is controllable,
and reduce the unpleasantness of the sound. If participants can consider unpleasant sounds as part of the environment they can control, they can create an environment in which unpleasant sounds do not bother them. In this study, melody generated based on the rhythm of the unpleasant sound
was played, and experiments were conducted to cognitively mask the unpleasant sound based on the perception that it can interfere with the environment as the melody can be adjusted. Results showed that manipulating the environment altered the perception of unpleasant sounds and improved task
performance by reducing their unpleasantness. Improved performance may be due to task-specific self-efficacy.
Navigating soundscape standardization: understanding barriers to the ISO 12913 implementation
Authors: ALETTA Francesco , XIAO Jieling , KANG Jian
Published: October 2024

This paper explores challenges and opportunities surrounding the implementation of the ISO 12913 series on soundscape, established by the International Organization for Standardization (ISO) to standardize definitions, frameworks, and methodologies for soundscape research. Through semi-structured
interviews with National Standards Bodies (NSBs) representatives and focus group discussions with soundscape experts and stakeholders, the paper unveils barriers such as a lack of national interest, resource constraints, and insufficient awareness and literacy about soundscape theory. This
study offers an opportunity to the broader field of environmental standards, giving practical insights for overcoming barriers and promoting the (further) adoption of ISO 12913 for healthier acoustic environments.
Sound quality evaluation tendency according to driving situation
Authors: YOSHIDA Junji , IRIE YUDAI , OKABAYASHI NAWOKI
Published: October 2024

In near future, autonomous vehicles are expected to be more popular due to the technology development. Through this transition from active driving situation to passive driving, the drivers' psychological state may change. This may cause change of impression to vehicle interior sound.
If the sound evaluation tendency is changed, we should improve autonomous vehicle interior sound by considering the difference. In this study, we investigated whether drivers' impression to interior sound change or not according to the driving situation through subjective evaluation test using
a driving simulator. In the test, an original driving simulator was prepared to reproduce identical sounds at both active and passive driving situation. EV and ICEV interior sounds were presented in the simulator for the sound quality evaluation about discomfort and sporty. Participants drove
the simulator under various driving conditions including acceleration and deceleration and evaluated the sound quality. As the result, interior sounds were found to be evaluated as more discomfort at passive driving situation than that at active situation. Furthermore, this tendency was observed
regardless the driving experience of participants. Accordingly, more interior sound reduction will be necessary for satisfying the customer in the autonomous vehicle development.
Delayed-X Harmonics Synthesizer algorithm for low frequency noise removal
Authors: HIRATA Ito , SHIMOKURA Ryota , IIGUNI Yoji , SASAOKA Naoto
Published: October 2024

As various technologies on noise reduction have improved their performances, slight low frequency noise has become more prominent in quiet environments. Since the traveling of low noise is difficult to be isolated by walls and earplugs, we aim an active noise control embedded in unoccluded
headphones. In this case, both desired sounds (e.g., speech) and unwanted noises pass through the opened ears, so the algorithm is required to adapt only the noise separating from the speech (selective cancelation). Therefore, our selected procedure was Delayed-X Harmonics Synthesizer algorithm
which produces pure tones in the opposite phase, because the generated pure tones in the low frequency can minimize the damage for the speech quality. To select the frequencies of pure tones, we focused on the fact that noise is more stationary than speech. The targets frequencies were determined
by a small frame-variation on the spectra of the error signals. Our simulations demonstrated that the low noise (< 100 Hz) could be reduced by 10dB even in the slight noise condition (SNR = 5dB), while the speech intelligibility (PESQ) was maintained. When our system is embedded in the
unoccluded headphones, the users will take daily conversation without any troubles of low noise.
Markov chain-based temporal correlation processing algorithm in reverberant environment by sparse Bayesian learning for acoustic imaging
Authors: SHEN Xingchen , SHI Tongyang , WU Ming , YANG Jun
Published: October 2024

Identifying sound sources is an important step in noise control, different sound source localization algorithms have been proposed and studied for almost a century. Most of the studies assume an ideal measurement environment, i.e., an anechoic or half-anechoic environment, but there
are limited studies discussing localizing sound sources in a reverberation environment. This paper proposes an acoustic imaging method in a reverberation environment based on the sparse Bayesian learning framework. Initially, a sound propagation model was established by accounting for the
multipath effects of the sound source in a reverberant environment. Based on the temporal correlation of a Markov chain, the algorithm is further improved in the sparse Bayesian learning framework. By leveraging the temporal correlation the algorithm provides, identifying the true source in
a reverberant environment becomes more accurate. Numerical simulation results have shown that the proposed algorithm achieves real sound source localization and eliminates the influence of image sources in contour maps under realistic reverberant environments.
Force sensitivity calibration of artificial mastoids
Authors: AU Chi Ho, Andrew , TUNG Kok Keung, Angus , LAM Hoi Shan, Brenda
Published: October 2024

The Standards and Calibration Laboratory (SCL) has set up a system for calibration of artificial mastoids to meet the growing demand for calibration of bone-conduction hearing aids and audiometers in the audiology industry of Hong Kong. An artificial mastoid (or mechanical coupler,
as specified in IEC 60318-6) is a device that mimics the mechanical characteristics of the human mastoid (one of the bones of the skull behind the ear). It is basically composed of a dome-shaped structure and a force transducer. This paper mainly illustrates the method for measuring the force
sensitivity level (in unit of dB re 1 pC/N) of an artificial mastoid in the frequency range of 125 Hz to 8 kHz. The calibration system has been automated to meet the demand for artificial mastoid calibration services in Hong Kong. This paper describes (i) the method of determining the force
sensitivity level of an artificial mastoid, (ii) the measurement model and uncertainty evaluation, and (iii) the measurement results and details of the calibration system.
Magnetorheological metamaterials for active broadband tuning of vibration attenuation
Authors: XUE Yu , LI Jinqiang , KRUSHYNSKA Anastasiia
Published: October 2024

We propose a class of magnetorheological metamaterial plates with tunable band gaps achieved by means of a frequency-feedback control law. This approach allows for the intelligent tracking of excitation frequencies that enables an active control of band gap bounds. The active control
mechanism is implemented through intelligent local resonators integrated into a main structure which comprise a mass and a magnetorheological elastomer (MRE) sensitive to an external magnetic field. The influence of the external magnetic field on vibration attenuation is examined using the
Galerkin method. Next, a closed-loop frequency feedback control strategy is employed to dynamically adjust the band gap in response to excitation frequencies. This strategy significantly broadens the effective band gap range of the metamaterial plate. Besides, we studied the effect of MRE
damping on broadband vibration reduction, underscoring its pivotal role in the band gap control for our magnetorheological metamaterials.
DOL3: Distilled OpenL3 audio embeddings for lightweight audio classification
Authors: KEHLING Christian , GOURISHETTI Saichand
Published: October 2024

Deep audio representations, also known as embeddings, recently became a popular alternative to conventional features like spectrograms for a wide range of audio classification tasks because of their domain-agnostic character and reduced training costs. Still, the usage is often limited
to rather computationally intensive system due to the nature of their extraction from large networks. This paper aims to minimize the computational costs of embedding extraction by distilling the knowledge of the OpenL3 audio network to a smaller student network. Results show that the student
network maintains comparable performance as the teacher network on various music and ambient noise classification tasks, while reducing the network size by over 90\% and the computational load by five times.
Effects of the earplug and external ear hardness of the direct transmissions induced by high-level impulse noises
Authors: BLONDE-WEINMANN Cyril , HAMERY Pascal , ZIMPFER Véronique , DE MEZZO Sébastien
Published: October 2024

The performances of Hearing Protection Devices (HPD) facing high-level impulse noises is limited by the transmission through the protector. This transmission can be evaluated by measuring the earplug's displacement along the ear canal axis. Previous measurements highlighted a displacement
proportional to the peak acoustic pressure in the protected ear canal. To better understand the consequences on the HPD performances, this evaluation requires to be extended. Thus, various configurations are studied with Acoustic Test Fixture (ATF) external ears and earplugs of low and medium
hardness. The earplug's peak displacements have been measured with a laser-vibrometer and the acoustic pressure with the ATF microphone. The impulse waves employed to excite the earplugs ranged from 150 dB to 180 dB peak. A medium hardness earplug inserted in a low hardness ear led to the
worst performances with a plug displacement of 200 µm and a peak noise reduction of 17.8 dB(SPL) for an impulse noise of 177 dB(SPL). For the best case, a maximum displacement of 66 µm and peak noise reduction of 28.8 dB(SPL) have been measured. These results suggest new perspectives
to improve the HPDs but also their evaluation through the choice of judicious ATF materials that conform to biological tissues.
Creating restorative corridors - Perceptual and physiological feedback of children on the audiovisual environment in primary school corridors
Authors: QU Fei , BAI Yun , XIE Qi
Published: October 2024

The corridor space of the primary school campus is frequently used for recess and relaxation by the students, which brings stress and emotional recovery from the intense academic work. How to integrate natural restorative environment into the corridor has attracted academic and practical
attention. Based on Kaplan's theory of Restorative Environment, this study combined subjective evaluation with physiological feedback to explore the primary school children's perception and evaluation of corridor space, and proposed the effects of different audio-visual indicators. Based on
a questionnaire survey of children's activities and restoration in two schools, the paper found the association between perceived restoration and high interaction behavior in the corridor, including floriculture and interacting with hands-on devices. The richness of amenities and colors in
the corridor space had the highest correlation with children's restorative ratings, followed by interface openness and sky visibility. Natural soundscapes also had a strong correlation with children's auditory restorability. Subsequent virtual audition experiments validated above findings,
suggesting the benefits of increased greenery, sky and natural sounds in reducing children's stress.
Pertinence of finite element method for impulse localization in urban environments
Authors: BLONDE-WEINMANN Cyril , HAMERY Pascal , OSPEL Matthias , IACOB David
Published: October 2024

Although urban combat is nothing new, recent conflicts have shed light on Western armies' difficulties when operating in such environments. Thus, new surveillance and hazard detection challenges in complex environments are addressed. A new decision aid tool for acoustic sensor positioning
has been developed to improve reconnaissance performance. The software's sensor location optimization kernel is based on a genetic algorithm developed by our partners from FKIE. It resolves successive localization problems using pre-computed Times Of Arrival (TOA) between an impulsive acoustic
source and various surveillance microphones. The present study discusses the pertinence of the Time-Domain Finite-Element Method (TD-FEM) to simulate wave propagation within an urban area to obtain TOA and resolve localization problems. The approach is compared to experimental measurements
in an urban area, and the pros and cons of the TD-FEM for this configuration are discussed.
Effects of honeycomb panel's finite dimensions on acoustic performance for lightweight sound insulation
Authors: PERCHAUD Julie , LECOQ Damien , FRUCHART Marianne , BLANCHARD Torea , LAGARRIGUE Clément
Published: October 2024

A honeycomb panel is considered as a lightweight sound insulation solution both numerically and experimentally. First, a unit cell with fixed and infinite periodic conditions is modeled, exhibiting high insulation levels up to the membrane's eigenfrequency. Closer to industrial applications,
a numerical model is developed, where the fixed conditions are applied only on the sides of the finite honeycomb panel. Taking into account structural modes of longer wavelength with this configuration, the panel's first eigenfrequency occurs at lower frequency than the previous case, yielding
to a reduced insulation power. Nevertheless, the low frequency performance obtained numerically on the honeycomb panel is validated with measurements under normal incidence plane waves and diffuse field excitations.
Efficient modeling of atmospheric infrasound propagation with the Semi-Analytical-Finite-Element (SAFE) method
Authors: MOTA Rafael , KIRBY Ray , WILLIAMS Paul , JACOB Stefan
Published: October 2024

Downward refraction in the lower atmosphere, attributed to winds and temperature inversion, can enable infrasound to efficiently propagate over long distances inside acoustic waveguides. In this study, we use the semi-analytic finite element (SAFE) method to predict this effect in stratified,
inhomogeneous, moving air for range-independent noise propagation over reflective half-planes. We present solutions for different temperature and velocity profiles and compare them to direct numerical solutions of the two-dimensional linearized Euler equations. The SAFE method separates the
exact two-dimensional wave equation for a stratified, inhomogeneous, moving medium by expressing the pressure field as a sum of vertical eigenmodes propagating in the range direction. This simplifies the acoustic problem into a one-dimensional eigenvalue problem. As this problem is addressed
with the finite-element method, the method can accommodate arbitrary wind and temperature profiles. For large, range-independent domains, the proposed procedure proves to be much more efficient than the tested direct numerical computations. Additionally, it converges against the exact solution
of the acoustic problem if enough modes are included in the calculation. Therefore, the method offers a viable procedure for benchmarking other pressure field prediction techniques.
On the influence of AVAS directivity on electric vehicle speed perception
Authors: MüLLER Leon , KROPP Wolfgang
Published: October 2024

Electric vehicles (EVs) typically produce minimal noise at low driving speeds, increasing the risk of accidents for pedestrians and other vulnerable road users. Therefore, regulations require EVs to use acoustic vehicle alerting systems (AVAS) that emit artificial warning sounds. Investigating
the human response to these AVAS sounds requires laboratory listening experiments, often based on auralizations. One of the challenges when auralizing electric vehicles is to include AVAS radiation directivity. However, it is currently unknown how this directivity affects the perception of
a vehicle passing by and whether an accurate reproduction is necessary for auralizations. We present a study on the influence of AVAS directivity on perceived vehicle speed, comparing different radiation patterns in combination with narrowband and tonal AVAS signals in a paired comparison
listening experiment with 31 participants. The results show that AVAS radiation directivity can significantly influence the perception of vehicle pass-by speed, with a tendency for omnidirectional patterns to be perceived slower than more directional patterns. Additionally, most participants
consistently rated either the tonal or the narrowband noise AVAS signal as faster throughout most comparisons. This indicates that AVAS signal type can affect vehicle speed perception with a subjective preference between tonal and narrowband noise AVAS.
Optimisation of underwater acoustic sensor networks
Authors: SERRE Ronan , HAMELOTTE Mathis , LEMARCHAND Laurent , DELLONG David , LAJAUNIE Myriam , PIHAN LE BARS Hélène , DEZAN Catherine , BOUTONNIER Jean-Michel
Published: October 2024

The oceans are the scene of intense economical and industrial activities. It is becoming even more competitive with recent military activities and the upcoming development of marine renewable energies. All of these activities have a significant impact on marine ecosystems and must be
carefully evaluated for any maritime planning. The marine environment is also a very effective medium for the propagation of acoustic waves over long distances, depending on the frequency, the source level, the static (bathymetry) and the dynamic (hydrology) oceanographic conditions. Such
conditions make acoustic sensors primary candidates for underwater investigations and the distribution of mixed sensors with various sensitivities, frequency bandwidths or positioning can be optimized for detection, localization or monitoring purposes. This contribution aims to present a methodology
based on evolutionary algorithms which considers the overall physical state of the marine environment and determines the optimal configurations of mixed underwater acoustic networks. The relevance of various objectives, or metrics, can be discussed, as well as specific search operators for
crossover and mutation based on preliminary results.
Partial equivalent sound pressure level as an approach to manage irrelevant sounds in environmental noise measurements
Authors: HELBOE Daniela Toledo , PEDERSEN Trond Iver
Published: October 2024

Residual sound and unwanted events are known factors affecting the accuracy of environmental noise measurements. ISO 1996-2 provides methods to manage these irrelevant sounds, for example by applying correction factors, but the methods require a degree of knowledge of the irrelevant
sounds that is not always practical or possible to obtain when performing long-term measurements with unattended monitoring stations in complex urban soundscapes. While automatic detection of irrelevant sounds provides the required information, it also allows for new approaches not described
in ISO 1996-2. In this paper, we discuss a metric called partial equivalent sound pressure level (Partial Leq), calculated after data samples with residual sound and unwanted events are identified automatically and replaced by project-specific values. Our hypothesis is that better estimates
of equivalent sound pressure levels (Leq) can be achieved with this metric, compared with the general methods given in ISO 1996-2. Comparisons of results are presented, together with a discussion of applicability of the Partial Leq metric and experiences gathered from its use.
Enhancing accuracy and robustness in FBS decoupling through Tikhonov regularization and unit balancing
Authors: NAM Jeongmin , PARK Sangyoung , KANG Yeonjune
Published: October 2024

Frequency-based Substructuring (FBS) enables the prediction of transfer functions for an assembled system based on those of a single-unit system. Conversely, FBS decoupling derives the frequency response function (FRF) of a single-unit system from the assembled system. This approach
is valuable when obtaining the transfer functions of a system is challenging due to boundary conditions and deformation conditions. FBS decoupling can enhance accuracy by using additional indicator sensors. However, this often results in significant noise due to the ill-posed FRF matrix inversion.
In this paper, Tikhonov regularization is employed to reduce noise-induced errors. Furthermore, this paper addresses the issue of inadequate Tikhonov regularization caused by the inherent scaling differences between the rotational and translational components within the FRF matrix. To rectify
this challenge, a unit balancing method is proposed to mitigate the influence of scaling differences. This method enhances the accuracy and reliability of FRF matrix inversion processes, contributing to enhanced noise reduction and robustness in practical applications.
Sources for railway community noise modeling
Authors: GENELL Anders , JERSON Tomas , ÖGREN Mikael , GUSTAFSON Andreas
Published: October 2024

For rail traffic, the wheel-rail interaction is one of the most important sources of noise, and is included in different ways in the noise calculation methods being used in Sweden today. However, if the rolling stock exhibit other noise sources it is not clear how they are handled by
the different calculation methods. Recent measurements in Sweden of the newly refurbished 'X2' passenger trains indicate that cooling fan exhausts mounted high up on the driving unit radiate noise at levels corresponding to the wheel-rail noise at speeds of 200 km/h. The NMT96 calculation
method currently used in Sweden represents the whole train as one line source per octave band, each placed at different heights. The newer Nord 2000 method, applies three sources at low heights for rolling noise and allows additional sources but without defining how to accommodate them. The
Cnossos-EU method puts all potential exhaust and fan noise at the higher of two sources, at 4 m above the rail. None of the models define how to apply a source to just the locomotive as sound power is given per meter train or per rolling axis. The impact on noise exposure and mitigation is
discussed in this paper.
Studying environment sounds using transfer entropy: Application to an urban park in the city of Milan, Italy
Authors: BENOCCI Roberto , ROMAN H. Eduardo , POTENZA Andrea , ZAFFARONI CAORSI Valentina , ALEX Prince , ZAMBON Giovanni
Published: October 2024

Sounds in large cities are usually characterized by multi-source overlaying components. This makes environment sound quality difficult to interpret, thus requiring different investigation approaches. This is the case of urban parks where the coexistence of anthropogenic and biophonic
sound sources makes the evaluation of the local soundscape quality challenging. In this context, we applied the transfer entropy measure to extract additional information with respect to the more classical approach of eco-acoustics. The case study refers to the Parco Nord of Milan, Italy,
for which classical soundscape analysis is already available. We used sound recordings (3.5h long each) taken over an area of approximately 20 hectares using 16 sensors. We calculated the classical eco-acoustic indices and studied the transfer entropy among all sites. The considered time series
corresponded to three representative eco-acoustic indices (Acoustic Diversity Index, ADI, Acoustic Complexity Index, ACI and Dynamic Spectral Centroid, DSC calculated for all the 16 sites with 1-minute time resolution) obtained after a principal components analysis. A preliminary interpretation
of the results is provided by selecting a representative index from one principal component and by comparing its behavior with a previous standard soundscape analysis performed by the authors for the same index and area.
Evaluation of noise emission from passenger cars in urban traffic a comparison between electric cars and cars with internal combustion engines
Authors: WADMAN FIlip , OLAFSEN Sigmund , FORSSéN Jens
Published: October 2024

Traffic noise is one of the largest contributors to environmental noise. Electrical vehicles have since the introduction been profiled as being quieter than the traditional car with internal combustion engine. Electrical passenger cars are becoming a larger part of the traffic fleet
today than before. Since it has been expected that the propulsion noise is significantly lower for electrical passenger cars. This means one could argue that the traffic noise should be expected to decrease in urban traffic where the propulsion noise from cars dominates. Measurements have
been conducted in Oslo, Norway, on electrical passenger cars and passenger cars with internal combustion engines at roads with speed limit from 15 km/h up to 60 km/h. The sound exposure level was compared between the different vehicle types. In addition, the sound power level was calculated
and compared with the CNOSSOS-EU method. Measurements show that electrical passenger cars were only marginally quieter than the cars with internal combustion engines.
Noise and vibration regulations for Uganda - with consideration for people and the environment
Authors: HOMMEDAL Inge , VERSTAPPEN Ivonne
Published: October 2024

As part of a cooperation between the Norwegian Environment Agency and the National Environment Management Authority in Uganda, we have worked on the development of legal noise and vibration regulations for Uganda. In this paper, we address the various noise sources that are relevant
for Uganda and its inhabitants. We discuss how these can be regulated bearing in mind that Uganda is an "outdoor society", while Norway is an "indoor society", like the rest of northern Europe. Regulating noise is in many ways a luxury phenomenon, especially in Norway,
which has a well implemented system with regulations and guidelines. Solutions that work in Norway can therefore not be implemented in Uganda in the same way. The same with limit values: these cannot just be copied. We discuss the process and present the framework for a system where the emphasis
is on regulating activities and their time of day, more than levels - this is easier to understand and enforce. The goal is to complete the regulations before the end of 2024 and hopefully it will lead to a more sustainable society, where e.g. fewer children are awake at night, because the
bar in the street is open around the clock.
SS 25268:2023, an acoustic standard for listeners and speakers
Authors: CHRISTENSSON Jonas
Published: October 2024

The sound environment in many classrooms is not good, and we know that poor room acoustics impedes learning and has a negative effect on teachers' voice health. Sound reflections in the room have a great impact on both speech intelligibility and speech comfort. SS 25268 is a Swedish
sound standard for, among others, school buildings. The standard uses reverberation time, RT, to put requirement on room acoustics. There is a connection between the amount of sound absorption in the room and RT according to Sabine formula. The problem is that Sabine formula requires a diffuse
sound field witch very seldom occurs in classrooms with acoustic ceilings. Another problem is when RT is evaluated with T20, the early reflections are not included, and early reflections have a great impact on speech intelligibility. The standard have been updated to a new version, SS 25268:2023.
In this standard there is an opportunity for landlords to put other requirements then RT to evaluate the room acoustics. The standard have an appendix to help landlords, principals and teachers to better understand how to put the right acoustic requirements on their school buildings to create
both good speech intelligibility and speech comfort.
Machine learning for locally periodic structure transmission modelling
Authors: FURMANOVá Aneta , HRUšKA Viktor , BEDNAříK Michal
Published: October 2024

This research aims to obtain an analytical transmission model for locally periodic structures with the approach of data-driven physics. So far, this task has been done mainly numerically for non-trivial geometries. From a dataset of Bloch phases generated for given frequency band and
structure geometry parameters, it is possible to learn equations relating dispersion relation to axis-symmetric geometry. The dataset is transformed into a lower-dimensional space by applying Principal Component Analysis (PCA) to reduce the complexity of the problem. In the newly obtained
coordinate system, the lower-dimensional patterns are extracted via symbolic regression. The resulting model is interpretable in terms of underlying physics and can be used, e.g., to propose an optimized design for a desired band gap width. Note that this has been so far possible only with
numerical optimization repeatedly going back and forth from geometry to the dispersion relation, and hence, it significantly contributes to the overall readability of the system features.
Large commercial business aircraft acoustic design with SEA
Authors: WANG Tongan , ANTESBERGER Norbert
Published: October 2024

As air travel becomes more frequent, customers are demanding a quieter cabin environment. Over the past two decades, Gulfstream has developed a suite of predictive tools based on Statistical Energy Analysis (SEA) to create a quiet cabin on business aircraft. This paper discusses the
most recent collaboration between Gulfstream and Jet Aviation to develop an acoustic design for a large commercial business aircraft. SEA analysis played a key role to identify the risks, determine the driving mechanisms, and develop solutions to meet the established target. Besides SEA model
development and analysis, this paper will also discuss some unique challenges to this aircraft and some innovations that were developed to mitigate them. One year after the acoustic design was released, flight test data on the completed aircraft confirmed the success of the acoustic design
as the quietest cabin to date on the specific aircraft type.
Annoyance evaluation of impact sounds on lightweight, concrete and cross-laminated timber floors - A comparative study
Authors: SKODA Sabrina , MUELLER-TRAPET Markus , MAHN Jeffrey , BATISTA DA CUNHA Iara
Published: October 2024

For people living in multi-unit residential buildings, neighbor noise and especially impact noise from neighbors, such as dropping objects or footsteps, can affect the quality of living of those who hear the noise. In order to support the inclusion of limits for impact noise in a future
edition of the National Building Code of Canada, a project at the National Research Council of Canada has focused on the perceived annoyance from different types of impact sounds for various timber floor-ceiling assemblies. The results from listening experiments showed poor correlation between
subjective ratings and objective single number metrics for impact noise due to persons walking without shoes. To extend this evaluation to a wider variety of floor-ceiling assembly types and to validate previous results, another listening experiment was conducted at the National Research Council.
Annoyance ratings for ball drops, hammer impacts and footsteps on different lightweight, concrete and cross-laminated timber floor-ceiling assemblies were compared.
Wooden multistorey acoustic test facility for vibration reduction indices measurement on different junctions of floor decking used to reduce flanking transmissions
Authors: KOUYOUMJI Jean-Luc , LOPETEGI Aitor , ALDALUR Ander
Published: October 2024

FCBA, CSTB and Cerqual joint forces together with the French acoustic wood technical commission, to create in 2020, an in-situ measurement mockup: the "Maquette Acoustique Bois". The mockup is a CLT based building of three floors construction, with four rooms on each level.
Measurements from junction characterization to air-borne and impact sound insulations can be performed. In this paper the "Maquette Acoustique Bois" is used to measure vibration reductions levels indexes Kij, in different configurations, where smart building systems junctions are
implemented to reduce flanking transmissions. Measurement results presented are generated from 4 types of junctions in between 2 rooms. The load bearing structure is Cross Laminated Timber (CLT). The measurement strategy is Statistical Energy Analysis (SEA). SEA involves cutting the structure
into subsystems and decomposing the spectrum into third-octaves or octaves. In this way, the exchange of energy flow in the substructures can be analyzed. The parameters that govern vibrational transmission between subsystems are damping and coupling loss factors and can be identified experimentally
by reversing the problem. The approach is, first, based on sub-structuring strategy of structure; second, on experimentally measured coupling and damping loss factors; third, on extracting vibration level difference one by one all flanking passes.
Noise reduction design of new residential buildings along urban roads-taking a residential district in Foshan as an example
Authors: DENG Yulong , WANG Hongwei , ZHANG Wenzheng , LI Shujie
Published: October 2024

Taking a residential district in Foshan along the city road as an example, the impact of urban road traffic noise on it is studied. Firstly, the data is monitored in the noise field, then three-dimensional simulation models of residential buildings and road distribution are established
in Cadna/A software, and noise simulation prediction is carried out according to the actual situation and relevant norms and standards. The predicted noise values of the exterior surface of residential buildings are obtained, which has exceeded the permissible interior noise level for residential
buildings. By comparing the application effects of noise reduction measures in buildings, the noise reduction design scheme of new residential buildings along urban roads is finally proposed: the sound insulation doors and windows that meet the requirements are adopted. After the completion
of the house, the indoor background noise and the sound insulation performance of the doors and windows are measured. The measured results show that the selection of sound insulation doors and windows is suitable and the indoor noise environment meets the design requirements of noise reduction.
The results are helpful to provide technical reference for the noise reduction design and renovation of other residential buildings along urban roads.
Study of the acoustic transmission characteristics of a pipe opening with a baffle considering structural elasticity
Authors: HU Zhi , LIU Gongmin , ZHAO Xiaochen , ZANG Zhenfei
Published: October 2024

Noise can radiate to the external environment through pipe openings. The acoustic transmission characteristics of the pipe openings greatly affect the efficiency of sound radiation. In fluid-filled elastic pipelines, the sound radiation is significantly influenced by the coupling between
the fluid and the elastic structure. The elastic structure studied in this paper includes the pipe wall, as well as the baffle attached to it. Waveguide analysis of fluid-filled elastic pipelines shows that the coupling results in the presence of several types of propagating waves within the
pipeline, even bellow the cut-on frequency. To evaluate the acoustic transmission characteristics of the pipe opening, it is necessary to separate the components of the lowest-order fluid type wave from these waves. A multi-case approach is developed to separate the target waves successfully,
thereby obtaining the characteristics of the pipe opening. The accuracy of the proposed method is verified, and the impact of structural elasticity is analyzed. Subsequently, the effects of the dimensions of the baffle are discussed.
Design of sawtooth-shaped acoustic metasurface for sound field manipulation
Authors: ZHU Zhe , HE Mu , XIA Liang
Published: October 2024

Currently, the goal of research on acoustic metasurfaces is mainly focused on achieving ultimate sound wave control, which often requires complex structural design. However, complex structures are often difficult for manufacturing and large-scale applications. To this end, our study
proposes a sawtooth-shaped metasurface with a simple configuration, easy fabrication and good wave control capability. First, we use "apparent wavefront theory" and "lattice diffraction theory" to predict the main reflected angles of sawtooth metasurfaces. Then, numerical
simulations were performed to validate the theories used and to analyze the conditions of their applicability. Finally, several sawtooth metasurfaces were designed to realize different functions such as large-angle reflection, acoustic focusing and uniform diffusion, which can also be verified
experimentally. In general terms, the sawtooth-shaped metasurface has broad prospects in the field of acoustics.
Analysis of noise characteristics of metal processing equipment
Authors: KIM Kyoung-Woo , JEONG A-Yeong , PARK Sun-woo , LEE Jong-hyeok , CHOI Min-gi , OK Chi-Yeol
Published: October 2024

The management and prevention of industrial injuries among workers are crucial in the work environment. Industrial injuries occur in various forms and have diverse causes, and noise-induced hearing loss accounts for a significant proportion of workplace injuries. Therefore, this study
aimed to measure the factory noise during engine-component (metal) processing for automobiles, where substantial noise-induced hearing loss is prevalent. The measurement results revealed that the 24-h equivalent continuous noise level (Leq) was approximately 83.8 dB(A), and the noise at two
points was higher than the noise exposure standard of 89 dB(A). These points were identified as locations where 2,200- to 3,500-ton casting machines were positioned on both sides to melt iron to produce components. The noise generated from each machine is assumed to have combined at these
points, resulting in elevated noise levels. The results were plotted on a noise rating (NR) curve. The NR values ranged from 81 to 83, surpassing the standard NR range of 60 to 70 that is commonly used in typical workplaces. The frequency band that determined the NR was 2 kHz. Therefore, measures
such as the use of porous sound-absorbing materials should be considered to attenuate the frequency range based on the noise characteristics.
Designing a practical physical framework for AI-enhanced sound detection and localization in vehicles
Authors: BANCHERO Lucas , LóPEZ Jose Javier
Published: October 2024

This paper presents the practical framework of an AI-implemented system currently in development for the detection and localization of external sound events to the vehicle. We delve into the initial block of the automotive project, analyzing sounds of interest and the noise we encounter,
addressing the strategic arrangement of the four microphones on the sides of the vehicle, conceived as the sound input system. This configuration not only optimizes signal capture but also acts as sensitive ears, allowing the system to effectively analyze the acoustic environment. To mitigate
wind interference, we have designed a microphone placement system that considers the vehicle's aerodynamics. The strategic location and implementation of aerodynamic protectors significantly minimize the impact of wind on the microphones, ensuring a sharper capture of acoustic signals. Complementing
this arrangement, we apply advanced noise elimination processes, further enhancing the quality of the captured signals. Although in its early stages, this project aspires to provide effective solutions for vehicular acoustic perception, marking the beginning of a journey towards innovation
in the detection and localization of sounds in mobile environments.