bluuebunny/crossref_metadata_2025 huggingface dataset:
Sound absorption of slit resonator with embedded aperture in linear and nonlinear regimes
Authors: SUN Wei , CHU Zhigang
Published: October 2024

This paper presents a slit resonator with embedded aperture (SREA) by embedding the slit-type neck into the cavity, and investigates its sound absorption characteristics in linear and nonlinear regimes. The theoretical acoustic impedance model of the SREA is established through transfer
matrix method. The theoretical, simulation and experimental results demonstrate that the SREA enhances oscillating mass without altering acoustic capacity through the embedded slit-type neck, enabling it to achieve quasi-perfect absorption at lower frequencies with the same external geometry
as traditional slit resonator. The formation and shielding of acoustic vortex caused by the high sound intensity increase the normalized acoustic resistance and decreases the acoustic reactance, causing the peak sound absorption coefficient to decline. This paper introduces a nonlinear correction
expression for the normalized acoustic resistance of SREA by analogy with cylindrical neck.
Waveguide finite element modelling for broadband vibration analysis of tyres including rotation and prestress
Authors: TREYSSèDE Fabien , CESBRON Julien
Published: October 2024

In the framework of tyre/road noise prediction, our aim is to introduce a waveguide finite element (WFE) method for broadband vibration analysis of rotating inflated structures of arbitrary cross-section. Approximating the geometry as perfectly circular, the finite element discretization
is restricted to the two-dimensional cross-section, enabling fast and high-frequency computations. Tyres are particularly challenging to model due to various complicating effects, often approximated or neglected in WFE models : rotation, inflation, structural anisotropy, heterogenetity, damping
among others. Our formulation uses Lagrangian perturbations of displacement in Eulerian coordinates, providing a concise way to express equilibrium equations in vibrating media initially moving, prestressed and subjected to fixed point forces (typically, contact excitations in rotating tyres).
The method comprises three steps: computing the steady rolling state (including rotation, inflation and centrifugal force), determining the undamped vibration modes superimposed onto the steady state (solving an eigenvalue problem of quadratic type owing to Coriolis acceleration), and obtaining
the forced response of the damped structure through specific orthogonality relationships (considering a specific form of damping). The WFE method is compared with a rotating shell analytical model from existing literature and is subsequently applied to a rotating tyre with heterogeneous cross-section
up to 4kHz.
Lateral vibration reduction in vertically installed shafts by active control with LMS algorithm
Authors: SONG Jaewon , KIM Byeongil
Published: October 2024

Machines such as generators and electric motors that use vertical shafts must avoid noise and heat problems caused by vibration. Especially in the case of vertical hydro generators, vibrations caused by water flow through the turbine and imbalance of components can lead to poor performance,
premature wear of components, and even system failure. Therefore, effective control of shaft vibration is very important for system maintenance and stable operation. To solve this problem, an active control method with Least Mean Squares(LMS) algorithm were applied to the lateral vibration.
In the study, the vertical shaft and the active bearing were modeled using the Finite Element Method (FEM), and the external hydraulic force was employed with an unbalanced mass. Simulations were conducted and effectiveness of the simulation results was verified through the active control
experiments. These results show that active bearings have the potential to solve vibration problems and extend the life of machines with vertical shafts, such as generators or electric motors.
A numerical analysis of isolated propeller noise using a lattice Boltzmann method approach
Authors: VAZQUEZ CASIQUE Raul , GOPALAKRISHNAN Lakshmanan , BOUSSUGE Jean-François , SAGAUT Pierre
Published: October 2024

Current environmental needs to achieve carbon neutral commercial aviation by 2050 require the development of new technologies and aircraft configurations. Among the different technological developments proposed, the use of open fan or Ultra-High Bypass Ratio configurations is of interest
due to their higher propulsive efficiency and performance. To support the development of such technologies, accurate and efficient tools early in the design stages are needed to predict aerodynamic performances and noise levels. One such tool is the lattice Boltzmann method, which can perform
high-fidelity aeroacoustic simulations of flows around propellers and engines. The lattice Boltzmann approach can be advantageous over other numerical methods due to its easy integration with complex geometries, its low numerical dissipation properties, and its high level of computational
efficiency. This paper presents the aerodynamic and aeroacoustic numerical study of an isolated propeller using the commercial lattice Boltzmann solver ProLB. Large Eddy Simulations were carried out using a compressible hybrid thermal version of the solver. An aeroacoustic analysis using a
Ffowcs-Williams and Hawkings acoustic analogy for far-field noise was carried out. The objective is to assess the capabilities of the solver to predict acoustic emissions of an isolated propeller towards the future study of an installed case.
Vibration reduction index improvement by adding resilient strips: influence of junction properties
Authors: DIJCKMANS Arne , PETTONI POSSENTI Vincenzo , BARBARESI Luca , CRISPIN Charlotte
Published: October 2024

Resilient strips can be used to decrease the structural transmission in junctions and thus limit the flanking sound transmission in buildings. In the standard ISO 12354-1, the efficiency of a resilient strip is characterized by the vibration reduction index improvement. To evaluate
the vibration reduction improvement, a standardized measurement method is needed. However, the vibration reduction improvement is not an intrinsic material parameter of the resilient strip and can depend on the mounting conditions and junction geometry. In this paper, the vibration reduction
index improvement is evaluated by means of numerical simulations carried out with a statistical model for junctions with resilient strips. The model was first validated by laboratory measurements. While the influence of the junction type (L, T or X) and transmission path (straight on or around
the corner) is limited, the influence of the plate properties (mass and bending stiffness) cannot be neglected, with differences in vibration reduction improvement of up to 20 dB.
On mediation: ethnographic and statistical analysis of an Indian helpline for reporting "Sound Abuse in Public Spaces"
Authors: GUILLEBAUD Christine , CHAUVEL Brian
Published: October 2024

This paper focuses on the Indian program "National Initiative for Safe Sound", a non-profit group based in Kerala. One of NISS's main actions is running a telephone helpline for residents "to report sound abuse in public spaces." It provides the population with its
first opportunity to speak out about the disturbing noises they endure, and is an invitation to nurture sonic citizenship via intermediation with noise-makers. Unlike governmental services that gather data in pre-established categories, the helpline foregrounds the fundamentally sociological
aspects of sound annoyance. As part of its telephone exchange, the helpline maintains a register recording some personal information, details on the context of the noise, and the indicated sound sources. Ethnographic and statistical analyses are combined to precisely identify the social and
geographical origin of callers, categories of sound sources, and the nature of the conflicts that emerge from the experience of unwanted sound. This paper describes local singularities and remarkable differences with comparable, earlier studies based on "official" noise complaints
in other countries. We favored an anthropological approach, offering an initial analysis of the profile of people calling in with complaints, and their highly conflictual relationship with the sounds entering the public space from places of worship.
Comprehensive evaluation on wearing and hearing comfort of over-ear headphones based on adjustable clamping force
Authors: YU Guangzheng , CHEN Zihan , WANG Yewei , WANG Tingting , LI Zhelin
Published: October 2024

Headphones are wearable devices that directly contact the human body. Ergonomics focuses on the wearing comfort associated with clamping force, which is closely related to the user's tactile perception. Additionally, as auditory input terminal devices, headphones should also encompass
the aspect of hearing comfort. Theoretically, slight and uneven clamping force may cause noise exposure, subsequently influencing hearing comfort. Conversely, an overloaded clamping force, while aiming to improve hearing conditions, may introduce discomfort for the wearer. Therefore, the current
work concerns the interplay between wearing and hearing comfort. In this study, four loudspeakers placed around a listener in a sound insulation room render a stable noise environment. A dynamometer mounted on a horizontal track radially supplies specific clamping force on the two earmuffs
of an over-ear headphone worn by the listener. Simultaneously, a comfort questionnaire was employed to investigate users' subjective perceptions of wearing and hearing comfort under various clamping forces. These results could provide a valuable reference for the design and evaluation of over-ear
headphones.
The Correlation analysis between ambient noise level at low-frequency range and wind speed in shallow water
Authors: KIM Byoung-Nam , JI Ho Youn , CHOI Bok Kyung
Published: October 2024

The ambient noise level in the ocean is an important consideration in the enhancement of passive sonar detection performance as well as undersea surveillance in a harbor area. The wind affects considerably the ambient noise level in the ocean. For this reason, many researchers have
analyzed the wind dependency of ambient noise levels in the ocean in the last few decades. However, this analysis is mainly limited to more than the frequency of 100Hz, because the ambient noise level below 100 Hz has been affected by sea current. In this study, we have investigated ambient
noise levels in the frequency range 10 Hz - 100Hz as the wind speed increases in shallow water. A drifting small vessel is used to exclude the effect of fluid noise generated on the surface of a hydrophone due to the sea current. The correlation between the ambient noise level and wind speed
in frequency range 10 - 25 Hz showed from 0.77 to 0.95. Whereas, it was from 0.11 to 0.69 in the frequency range 32 -100 Hz. The maximum correlation appeared at 10 and 16 Hz. This was much higher than those measured in the frequency range 1kHz - 25 kHz.
Advances in elevator dynamics
Authors: TRACHSEL Mathis
Published: October 2024

The dynamics of an elevator system and therefore the ride quality in the car is governed by the masses, rope elasticities and a variety of excitations involved. In case of tall buildings, the rope mass significantly participates to the vertical dynamics and effects of longitudinal waves
result in complex system interactions. The mechanical model presented allows to accurately simulate the vertical dynamics of an elevator system, including effects of wave propagation with reflection, standing waves and resonances depending on the parameters involved. Considering the drive
control and its parameters as well, testing efforts can be heavily reduced, as ride quality and suitable control parameters can be determined in advance. To further improve ride quality, possible modifications of damping, decoupling and tuned mass dampers can be added to the model and real
system if needed. Simulation results are presented and compared with measurements and provide additional insight into the rope dynamics, which are not accessible by measurements.
Selective noise control by adaptive bandpass filter and secondary aural cartilage source
Authors: KATO Yoshiki , SHIMOKURA Ryota , SASAOKA Naoto , IIGUNI Yoji
Published: October 2024

When a transducer is put on an aural cartilage, the transmitted vibration generates sound in the external auditory canal (i.e., cartilage conduction). Different from conventional earphones, the cartilage conduction technology enables the use of earphones without occluding the canal.
However, the opening ears allow both desired sounds (e.g., speech) and unwanted noises to reach the eardrums. To minimize only the noise selectively, our study introduced filtered-x least means square algorithm combined with adaptive bandpass filter (ABF-FxLMS). The ABF-FxLMS stored the narrowband
noise separating from a speech and transferred it to the FxLMX as a secondary sound source produced via the cartilage conduction. The adaptive bandpass filter actively adjusted to changes in the center frequency of noise, and the ABF-FxLMS ensured effective noise reduction permitting the passing
of speech. Our simulations demonstrated achieving approximately 19 dB reduction in the noise while keeping the speech quality. A coming cartilage conduction device will enable conversations in noisy environments.
Rotating and stationary sound sources separation method based on MCB
Authors: NING Fangli , HOU Hongjie , JIA Deyu , WANG Haiwei , WANG PengChuan
Published: October 2024

Traditional beamforming methods do not effectively separate the mixed field of sound sources for different rotational speeds. The coexistence of these sources often manifests out-of-focus sources (for instance, stationary sources appearing with a rotational focus), thereby blurring
the beamforming outcomes. Most existing algorithms for segregating rotational different speed sources employ a virtual rotating array utilizing ring arrays. However, due to the constant microphone spacing, the acoustic imaging of the ring array suffers from the interference of high-level side
lobes. In this work, a hybrid deconvolution method based on modal composition beamforming is used to explore the ability of a multi-arm spiral array to separate different speed sources. Considering the even energy distribution from the out-of-focus source along the circular trajectory, the
beamforming result of out-of-focus sources exhibits a weaker amplitude than the source amplitude. Therefore, out-of-focus sources can be considered noise. First, the point spread function is derived based on the modal transfer function. Then, a system of linear equations is constructed based
on an incomplete cross-point spread function matrix. Finally, the source separation is solved through sparse-constrained deconvolution. Simulation and experimental results demonstrate that this method can accurately locate and separate different rotational speed sound sources.
Small-scale noise mapping for arbitrary regions using open source noise prediction module "NoiseModelling" and global databases
Authors: TAGUSARI Junta
Published: October 2024

Extensive noise mapping has been crucial in shaping noise mitigation policies; however, assessing noise exposure in different scenarios remains challenging due to static maps that only represent pre-calculated sound levels. To fill this gap, this study introduces a novel noise mapping
framework tailored to calculate sound levels in specific environments within small, arbitrary regions. Using the open-source noise prediction tool NoiseModelling and global databases of road networks, buildings, terrain, and population distribution on QGIS, this framework seamlessly integrates
noise mapping procedures, including comprehensive data collection, receiver placement, sound level calculation, and visualization. The user-friendly graphical interfaces enable quick and easy generation of noise maps. The approach offers flexibility through customizable geometry and parameter
settings to account for variations in noise sources and propagation characteristics, thereby providing stakeholders with valuable insights for policy formulation, environmental impact assessment, and community engagement. This methodology not only improves the accessibility and relevance of
noise mapping but also empowers decision makers to implement tailored noise mitigation strategies that promote healthier and more livable environments.
The effect of fan-type inducer blade tip geometry on cavitation behavior and noise in an industrial centrifugal pump
Authors: UTSUMI Haruto , EJIRI Shinichiro , MIYABE Masahiro
Published: October 2024

Cavitation is one of the biggest problems in industrial centrifugal pumps because it causes serious vibration and noise. Therefore, there is a demand for pump manufacturers to prevent problems due to the cavitation before delivering products to the site. Noise is considered to increase
due to the development of cavitation at the tip of the inducer blades. In this study, the location of cavitation development was controlled by changing the inducer blade tip geometry to reduce noise. A centrifugal pump with a fan-type inducer was operated to measure noise at various cavitation
numbers and flow rates with a microphone set up on the outer wall near the inducer. A visualization experiment using an acrylic casing around the inducer, a high-speed camera, and strobe light was also conducted to observe the behavior of cavitation development. The relationship between cavitation
form and noise was investigated in detail.
Exploring cross-modal perception: audio, visual, and thermal responses to changes in audio-visual Stimuli within virtual urban parks
Authors: NITIDARA Ni Putu Amanda , SARWONO Joko , SUPRIJANTO S.
Published: October 2024

Human perception is an essential factor in soundscape. Humans are multisensory beings, and thus, their perceptions are influenced by various multisensorial experiences. Our perception of a soundscape is not solely influenced by the sound in itself but also by various non-auditory factors.
This research examines how visual factors, other than auditory, influence people's perceptions in public open spaces. An experiment was conducted using audio and visual stimuli. Three setups were compared: audio-only, visual-only, and combined audio-visual stimuli to observe differences in
the respondent's perception. Furthermore, this research examines not only auditory perception but also visual and thermal perceptions, all of which are known to be important in public open spaces. The statistical test ANOVA showed that the Audio-Visual and visual-only stimuli produced a significant
difference (p<0.05) in the thermal perception. On the other hand, the Audio-Visual and audio-only stimuli did not result in any significant differences. This study contributes to understanding the interaction between different sensory modalities and how it affects our perception. The findings
underscore the importance of considering multisensory experiences, including auditory, visual, and thermal aspects when designing or evaluating environments in urban settings.
Comparative analysis of acoustic testing methods of a multi-layered material: uncovering the membrane effect
Authors: FERNANDEZ COMESANA DANIEL , SCHMAL Jared , PULJIZEVIć Maro , POLJANSEK Tadej , POLAK Andraz
Published: October 2024

This paper presents a comprehensive investigation into the differences observed when evaluating the acoustic properties of a multi-layered material using different standardized methods. The primary focus is on the membrane effect of the upper aluminum layer, which has been shown to
contribute to the overall acoustic absorption. This phenomenon, crucial for applications requiring enhanced acoustic performance at lower frequencies, is observed in tests conducted with large sample sizes but remains undetected in impedance tube measurements. Through a series of experiments,
including reverberant chamber, impedance tube, and in-situ absorption measurements, this study investigates the complexities of accurately estimating sound absorption characteristics in multi-layered materials. Additionally, 2D colormaps to visualize the spatial distribution of sound absorption
across different samples are examined, offering deeper insights into the uneven absorption patterns that standard testing methods may overlook. The experimental findings highlight the importance of selecting an appropriate evaluation technique for multi-layered materials, particularly in applications
where acoustic performance is critical at lower frequencies.
Advanced concept for noise monitoring in smart cities through wireless sensor units with AI classification technologies
Authors: DOMAZETOVSKA MARKOVSKA Simona , ANACHKOVA Maja , PECIOSKI Damjan , VIKTOR Gavriloski
Published: October 2024

The rapid urbanization in the cities has indicated the importance of sustainable development for creating smart cities with high quality of life. Environmental noise as one of the main concerns has to be addressed according to International Directives and Legislation. Traditional noise
estimation methods are costly and time-consuming, but the emerging technologies like low-cost wireless sensor units (WSUs) offer more granular data collection and analysis. Requirements for more accurate assessment of the noise pollution by detecting the dominant noise sources impose the need
to apply novel approaches in the technical systems for noise monitoring. To this aim, this paper investigates the advanced methods for noise monitoring through WSUs with AI classification technologies. The proposed concept of the device not only quantitively describes the noise pollution,
but also tends to recognize the class of the disturbing sound events. The accuracy of the WSUs are configured by comparing the results with professional hand-held analyzer, showing powerful and affordable low-cost units able to publish results through cloud and fog computing based on the IoT
and smart city technologies. The paper discusses the challenges for merging noise measurement technology and the AI algorithms to classify and quantify the different classes of sound events.
Spatial windowing for finite-size incident sound transmission coefficient of multi-component surfaces
Authors: TERZAKIS Michail Evangelos , VAN HOORICKX Cédric , HORNIKX Maarten
Published: October 2024

Spatial windowing was introduced for alleviating problems related to the infinite behaviour of rectangular surfaces. For finite rectangular surfaces, the radiation efficiency can be computed very efficiently. Considering multi-component surfaces such as a building façade, which
include both rectangular and non-rectangular surfaces (e.g., wall and window), an adjusted version of the spatial windowing is here applied, using a divide-and-conquer approach of rectangular surfaces and applying the correlation between two adjacent surfaces. Hence, the transmission coefficient
and sound reduction index (SRI) of multi-component finite surfaces can be calculated. For a glass surface, the adjusted radiation efficiency presents good agreement with the non-adjusted one. Applying a convergence study to the adjusted radiation efficiency with respect to the glass surface,
it was found that a coarsely divided surface approximates the relative undivided surface very well, under far-field conditions. Similar results were obtained with respect to the SRI of a single-component (glass) and a multi-component (glass and wall) surface. Applying both far-field and near-field
conditions in a multi-component surface, the glass typically dominates the total SRI, especially with increasing its area. However, in the coincidence region of the wall, the SRI of the wall can be decisive for the total SRI.
Geometric optimization for localized attenuation of subsonic slit-based open acoustic barriers
Authors: CASTIñEIRA-IBáñEZ Sergio , TARRAZó-SERRANO Daniel , SAN BAUTISTA Alberto , URIS Antonio , RUBIO Constanza
Published: October 2024

In recent years, many solutions have been developed to reduce noise from different sources. One of these solutions is acoustic barriers. An acoustic barrier is a structure designed to reduce noise transmission between areas by blocking the direct path of sound. Open acoustic barriers
are a valuable solution for technical and industrial plants. They allow airflow and visibility. Given the need for localized attenuation in these environments, it is possible to use numerical models to improve effectiveness and thus increase insertion loss in a region of interest. This study
has used numerical simulation tools to provide degrees of freedom in placing the different elements of a subsonic slit-based open barrier. It has been shown that by rotating some of the elements and determining an area of interest, it is possible to improve the effectiveness of the barrier.
These results allow using all the elements with the same topology to individually attack noise pollution problems in their location and frequency range.
Open noise barriers for peri-urban environments
Authors: TARRAZó-SERRANO Daniel , CASTIñEIRA-IBáñEZ Sergio , SAN BAUTISTA Alberto , RUBIO Constanza , URIS Antonio
Published: October 2024

Noise as an environmental pollutant in peri-urban environments has become a constant annoyance. Implementing noise-reducing elements to solve this problem is necessary to mitigate noise nuisance and promote the quality of daily life in these areas. This project analyses using trees
as scattering elements, using the typology of acoustic barriers based on sonic crystals. Different tree configurations are analyzed using numerical models to determine their effectiveness in scatter sound and absorption, complemented with field studies to validate the models. The results show
that specific arrangements and species combinations can significantly reduce noise, proposing a sustainable and aesthetically pleasing solution for noise mitigation in peri-urban areas. This approach offers an effective method of noise control and contributes to the improvement of the ecosystem
surrounding these populated areas. Integrating acoustic engineering and ecology principles in this study opens new perspectives in the design of noise barriers, marking a milestone in the search for innovative and environmentally friendly solutions.
Why should eventfulness be replaced with arousal in the Perceived Affective Quality Scale for soundscape research?
Authors: NAGAHATA Koji
Published: October 2024

The two attributes "eventful" and "uneventful" are proposed for those evaluating the perceived affective qualities of soundscapes in ISO/TS 12913-2. In this paper, from two points of view, the reasons why those attributes should be replaced with those regarding arousal
are discussed. From the viewpoint of psychology, affective quality is defined as the ability to cause a change in core affect and, therefore, can be describable in terms of the same two dimensions as core affect. On the other hand, "eventful" and "uneventful" are not affective
but cognitive attributes. It is a theoretical mistake to term different dimensional attributes as affective ones. From the viewpoint of translatability, the Japanese-translated word for "uneventful" cannot be distinguished from those for "calm." This fact suggests that
at least one culture exists in which the semantic difference between "uneventful" and "calm" is not essential. For those in a culture where the semantic difference between two attributes is not essential, it is natural that the evaluation using those attributes is also
inessential. The scales proposed in the international standards should be meaningful beyond the cultures. From this perspective, we can say that "uneventful" is not the appropriate attribute for using ISO standards.
Performance improvement of active sonar target classification using feature fusion
Authors: HWANG Young-Sang , KIM Geun-Hwan , HONG Woo-Young , KWON Hyuck-Jong , CHOO Young-Min
Published: October 2024

In this study, we propose a neural network architecture considering feature fusion to improve active sonar target classification, where training data is scarce. We use various hand-crafted features with different perspectives for the active sonar one- and two-dimention raw data to enhance
target classification performance. We use two kinds of features, in 1D feature and 2D features, because different perspectives on the same sample complement effectively by exchanging. For this, we contrived attention based complementary learning module to extract comprehensive features using
the two kinds of features. To verify the generalization performance of this model, two real-ocean datasets were used and the classification results are compared with existing DL models.
Toward the symbiosis and co-prosperity between Narita International Airport and the local community in line with airport capacity enhancement
Authors: FUJITA MASAO , SUGIMOTO CHIHIRO
Published: October 2024

Narita International Airport is working toward "Further capacity enhancement of Narita International Airport", and will be able to increase the annual departure and arrival capacity from the current 300,000 to 500,000 times by constructing Runway C, as well as the extension
of Runway B. This report describes what kind of initiatives and measures Narita International Airport Corporation (NAA) takes in collaboration with the local municipalities and residents based on the basic idea that "Airport development is regional community development" including
the efforts to investigate noise impact on the living environment, including health effects. Narita International Airport has been regarding its symbiosis measures, airport development, and regional development as a trinity and various efforts have been made. In addition, since the opening
of the airport, NAA has taken detailed measures from various angles to address the problems stem from being an inland airport. This report describes the background to the implementation of the investigation of the impact of aircraft noise on the living environment, including the impact on
health effects, at Narita International Airport. The technical aspects of the study will be presented in another report.
Optimization and adjustment of indoor acoustic environment of theatre - Taking Guangzhou design capital-design hall theatre as an example
Authors: ZHANG Wenzheng , WANG Hongwei , LI Shujie , DENG Yulong
Published: October 2024

Theater is a place for all kinds of performing arts, and its design and function are usually diversified to meet the needs of different types of performances. odeon software is calculated with the sound source method and sound line tracking method, and adopts the Lambert scattering
algorithm to calculate the sound diffusion, so that the simulation process is more and more realistic, and the calculated results are closer to the actual measured values. using odeon software to simulate the Using ODEON software to simulate the Guangzhou Design Capital - Design Hall Theater,
according to the simulation results, the reverberation time is relatively short and other issues such as corresponding adjustments and recommendations, to give the Guangzhou Design Capital - Design Hall Theater indoor sound-absorbing material layout plan.
Improving bone-conducted speech quality: a novel approach based on speech production principles
Authors: RICHARD Julien , ZIMPFER Véronique , ROTH Sébastien
Published: October 2024

Bone conduction microphone (BCM) which records speech that travels through at least one human tissue, demonstrates a significant advantage in capturing voice in noisy environments. The ergonomic design and versatile placement options of BCMs further enhance their utility, allowing integration
with various head equipment such as earplugs, glasses, helmets, or NRBC masks. Despite these advantages, ensuring the quality and intelligibility of recorded speech remains a challenge. Past efforts have involved various post-treatments uniformly applied to all signals, to address these drawbacks,
with limited success. In this paper, we introduce a novel approach aimed at enhancing BC speech quality by implementing a select number of filters grounded in speech production principles. In this study, treatments both dependent and independent of phonemes are applied. Subjective tests are
conducted to assess the efficacy of these filters and compare their effects.
Extraordinary viscous absortion by phononic supercrystals
Authors: SANCHEZ-DEHESA Jose , IBARIAS Martin A. , KROKHIN Arkadii
Published: October 2024

An effective medium theory has been developed to study the viscous absorption of a doubly periodic phononic crystal, here denominated as supercrystal (SC). In practice, the SC is made of hard cylindrical scatterers embedded in a viscous fluid and consists of a combination of two phononic
crystals with lattice periods, $a_1$ and $a_2$. The decay coefficient of sound due to viscosity is calculated analytically at low frequencies when both lattices homogenize. The viscous absorbance of finite SC slabs calculated with the analytical model is supported
by exact calculations based on the finite element method (COMSOL simulations). In addition, results for the complex sound speed show a good agreement with the experimentally extracted sound speed.
SICALC - A new tool for aircraft noise calculations
Authors: HAUGE Leo , OLSEN Herold , RANDEBERG Rolf Tore
Published: October 2024

This paper investigates how aircraft noise calculations can be made available for everyone. Traditionally, tools for aircraft noise calculations have been characterized by high complexity and numerous variables that users must consider. This complexity has necessitated expert competence
to conduct calculations, limiting the accessibility of these calculations. SICALC (SINTEF Noise Calculator) is a new web-application tool that aims to challenge this practice and make noise calculation available to everyone while ensuring high-quality, reliable, uniform, and error-free results.
The paper will discuss how the aircraft noise calculation method, NORTIM (the Norwegian Topography Integrated Model), has incorporated new technology and design principles into SICALC. It will also address the various challenges associated with this development.
Source localization at low frequency using deconvolution of the waveguide impulse response
Authors: LE COURTOIS Florent , LAJAUNIE Myriam , KINDA G. Bazile
Published: October 2024

Matched-mode processing (MMP) methods have been widely investigated for source localization and geoacoustic inversion. For horizontal line arrays (HLA), it aims at retrieving the horizontal wavenumbers and thus at inferring source range and bearing. In this work, the matched-mode is
performed by applying the deconvolution of the waveguide response in a narrowband context in order to improve the localization accuracy. Deconvolution usually refers to a sparse framework when the number of sources is smaller than the number of sensors of the HLA. The Orthogonal Matching Pursuit
algorithm is then used in this work. First results from numerical simulations for Pekeris waveguide highlight better localization accuracy than MMP. The deconvolution shows as well stronger robustness to mismatch in the sound speed values of the seabed. Results from measurement campaign, involving
large HLA, low to ultra-low frequency and water depth up to 1500 m are investigated as well.
Design, optimization and validation of a small cabin for standardized objective measurements of earmuffs and earplugs on artificial head (ATF) according to ISO4869-3
Authors: FOHR François , SANALATII Maryna , RENCKLY Kevin
Published: October 2024

The attenuation of hearing protection devices is currently mainly measured using the REAT (ISO 4869-1) standardized subjective method. However, during the development step, manufacturers need to carry out a numerous tests quickly making the REAT method unsuitable due to its need of
a large number of subjects with associated training time and represents a significant cost. As an alternative, the standardized objective method (ISO 4869-3) uses an artificial head (ATF) in a controlled acoustic environment. Delta Plus called on CTTM to provide a test facility compliant with
the 4869-3 standard, and designed with reduced dimensions to fit easily into its test laboratory. The presented work describes the steps of design, development and validation of a measuring cabin meeting these requirements. The search for a suitable geometry for the cabin volume is based on
numerical modeling using boundary elements. The cabin, built using this initial approach, is then empirically optimized using different types of diffusers to meet sound field homogeneity criteria. Comparisons of measurements made using both subjective (ISO 4869-1) and objective (ISO 4869-3)
methods are presented at the end.
ECMA-418-2 roughness, a challenging implementation
Authors: WANTY Salomé , GLESSER Martin , CASAGRANDE HIRONO Fabio
Published: October 2024

Over the past decade, psychoacoustics has grown significantly and sound quality metrics have become an easy way to include the human factor in NVH analysis. Most of these metrics have been defined by standards (ISO, DIN, ANSI or ECMA), which should promote their use in industrial applications.
MOSQITO is an open-source project providing implementations of sound quality metrics in Python(e.g. loudness ISO 532-1, sharpness DIN 45692, SII ANSI S3.5) along with complete documentations and validation procedures. In 2020, the European Computer Manufacturers Association released the ECMA-418-2
standard, revised in 2022, describing new loudness, roughness and tonality implementations based on a common hearing model. During the implementation of the roughness metric in MOSQITO, it appeared that some implementation instructions are subject to interpretation, and some information was
missing in the standard to allow for a valid computation of this metric. Moreover, the standard does not define some validation cases, which can limit the spread of its metrics. This paper highlights these difficulties for each section of the calculation process, and proposes new steps that
would aid the user's understanding and implementation of the standard.
Diagnosing multiple faults in rotating machinery using empirical mode decomposition and blind source separation methods
Authors: YELVE Nitesh.P , KUMAR Sunil , SINGH Swapna
Published: October 2024

It is a challenging task to accurately diagnose multiple faults in a rotating machinery. In this paper, the authors have used empirical mode decomposition (EMD) and blind source separation (BSS) methods for this purpose. A portable rotating machinery setup is made in the laboratory
and faults such as bearing inner and outer race faults, angular misalignment are created into it. The vibration data is collected using SPM made LEONOVA DIAMOND(r) FFT analyzer and processed using CONDMASTER RUBY(r) and MATLAB(r) softwares. Firstly, wavelet transform is applied to the signal
to denoise it. After this, EMD is implemented to decompose the signal into different intrinsic mode functions (IMFs). After preprocessing these IMFs using the principal component analysis (PCA), BSS is used to extract fault-related information from the IMFs. A comparison of the results obtained
from EMD and PCA-BSS is also presented in the paper. Keywords: Rotating machinery, Multiple faults, Vibration data, Wavelet transform, Empirical mode decomposition, Blind source separation, Principal component analysis.
Setting up light and noise maps to define the contours of a reserve of darkness and silence in Sherbrooke, Québec, Canada
Authors: BISSON Jérôme , CôTé Sabrina , CURRY Henri , FAUTEUX William , HATIER Jérémie , LABSIR Othmane , RIVARD Léa , GUY Audrey , BELLEAU-MAGNAT Gaëlle , APPARICIO Philippe , ROBY Johanne , ROBIN Olivier
Published: October 2024

Urban sprawl brings cities closer to natural areas, making them cohabit is a significant environmental challenge. Densification can also increase light and noise pollution, negatively affecting human and biodiversity well-being. Grounded on a collaboration between a college and a university,
this work combines brightness and noise maps to establish the contours of a reserve of darkness and silence in Sherbrooke's Mont-Bellevue Park (Québec, Canada). The light and sound environments of the city are mapped by the research team using two devices mounted on vehicles or bicycles:
a multispectral and multidirectional brightness sensor and a sound level meter. Long-term and fixed-point light and noise measurements were also conducted to develop the mobile measurement protocol. Wind tunnel measurements in an anechoic chamber were finally used to determine the effect of
travel speed on measured noise levels, showing that speeds of less than 15 km/h ensure unbiased acoustic measurements using a windscreen. Perspectives include using the Noise Capture application to provide crowdsourced and additional noise levels at fixed measurement points. The open-source
Noise Modelling tool will provide us with calculated environmental noise maps to be compared with measured data.
Electromechanical coupling optimization for a sandwich beam activation using piezoceramics
Authors: CAMUS Corentin , EGE Kerem , COTTINET Pierre-Jean , SAUNIER Lambert , RICHARD Claude
Published: October 2024

Sandwich beams composed of two stiff carbon fiber skins and a viscoelastic core are often used to passively dissipate energy through the activation of shearing in a specific frequency range. Semi-active or active energy dissipation can be made possible on those structures adding piezoelectric
patches, coupling mechanical vibration energy and electrical energy. J.L. Guyader et al. [jsv, 1978] theorized a frequency dependent equivalent dynamic model of a sandwich structure, recently extended to the homogenization of anisotropic multi-layers by F.Marchetti et al. [jsv, 2020]. This
frequency-dependent stiffness of the beam has to be taken into account in the piezoceramic thickness definition in order to optimize the global electromechanical coupling coefficient. An analytical model is derived from the works of F.Marchetti et al. and adapted to predict the first vibration
mode of a finite cantilever beam instrumented with a piezoelectric patch. The electromechanical coupling evolution is then calculated with the proper boundary conditions and for different PZT ceramic thicknesses. This model is furtherly used to define the best transducer configuration for
a given sandwich structure beam.
Predicting the acoustic attenuation of dual protection
Authors: TROMPETTE Nicolas , CHEVRET Patrick
Published: October 2024

When workers are subjected to very high noise levels, one way of protecting their hearing is to use dual protection, i.e. to wear earplugs and earmuffs simultaneously. The literature shows that the acoustic attenuation provided by a dual protection is much lower than the sum of the
acoustic attenuations provided by each of the hearing protectors, but it does not propose any method for evaluating it, which poses a risk to safety. A review of the literature was undertaken. The acoustic attenuations of a number of combinations were collected. At the same time, tests were
carried out on four combinations, in order to supplement the relatively old data in the literature with up-to-date data. On the basis of this data set, formulas were established to calculate the octave-band attenuations of the combination of two protection devices from their respective attenuations.
The overall attenuation indices (SNR, H, M and L) can be deduced to select hearing protectors according to noise exposure. These indices are predicted with good accuracy, less than 3dB. This work will enable occupational health and safety professionals to assess the protection provided by
dual protection, and thus to recommend it in a fully safe way.
Assessment of industrial noise nuisance - guidelines for calculating the HA index - results of surveys on the population covered by strategic noise maps in Poland
Authors: MALEC Tomasz
Published: October 2024

The work contains the results of research conducted in the field based on the ISO 15666 standard. The aim was to assess the annoyance of industrial noise around sources mapped as part of strategic noise maps made in Poland. The research area included five selected industrial areas,
among all those mapped in Poland. 431 people were surveyed. The analysis included residents of five noise ranges: 50 - 55, 55 - 60, 60 - 65, 65 - 70 dB, described by the LDWN index. The result of the research was the determination of the dose-effect relationship for the HA (High Annoyance)
index and the method of its calculation for the sample analysis area.
Loudness and preference judgments for noises of a heat pump
Authors: STüRENBURG Lara , BRAREN Hark , ASPöCK Lukas , FELS Janina
Published: October 2024

An increasing number of heat pumps have recently been installed to replace conventional heating systems to provide more environmentally friendly and energy-efficient indoor heating. Most commonly, air-to-water heat pumps are chosen. However, the sounds of their fan and compressor can
lead to noise complaints and can reach the limit of noise emission regulations. To achieve a more pleasant environment, research is conducted to reduce the perceived noise of heat pumps. As part of an interdisciplinary research project, this study aims to investigate the annoyance ratings
of a heat pump and characterize them in terms of equivalent loudness and preference penalties. The study uses a two-alternative forced-choice (2AFC) method with a 1-up-1-down rule to measure the point of subjective equality for six stimuli representing different operation states of the investigated
device. This experiment aims to identify differences between loudness and preference, and combined with an evaluation of psychoacoustic parameters, its results are used to improve the acoustics of heat pumps and the overall user experience.
Computing the dynamic response of a periodic structure coupled with a nonlinear junction using the harmonic balance method and Floquet-Bloch modelling
Authors: MAHé Vincent , DROZ Christophe , CHOUVION Benjamin , MELOT Adrien
Published: October 2024

Structures constituted of assembled sub-components are often subject to nonlinear effects due to the presence of joints or contacts, which can induce higher-order harmonics of the source excitation. In the context of periodic structures, these nonlinearities cannot be tackled using
the Floquet-Bloch theory in its usual harmonic formulation. This study hence presents an adaptation of the classical Floquet-Bloch theory to address multi-harmonic systems arising from a finite number of localized nonlinearities in periodic waveguides. We adopt the Harmonic Balance Method
to recast the governing equations into a nonlinear algebraic system, which can then be solved using numerical continuation algorithms. To demonstrate the validity and benefit of this approach, the predictions derived from the proposed methodology are compared to results obtained through conventional
Finite Element analysis. Excellent agreement and a notable reduction in computational cost are observed. This efficient procedure for analysing the nonlinear dynamic response of periodic waveguides opens up new possibilities in the study of damaged composite structures.
Determination of reverberation time in large educational auditoriums
Authors: JAGNIATINSKIS Aleksandras , FIKS Boris , MICKAITIS Marius
Published: October 2024

According to the current regulation, acoustic comfort in educational buildings in Lithuania is ensured by applying sound insulation of structures and limiting excessive room reverberation. The maximum reverberation time values described in the document depend on the building's acoustic
comfort class, room volume and frequency range. In order to determine the design values of the reverberation time for larger auditoriums, there is a need for consultations with an acoustic expert. This paper presents some typical examples of reverberation time measurements in new, old and
modernized large lecture halls. The measurement results indicate good practice in the design and installation of new auditorium, as well as the nature and importance of acoustic problems in old and modernized ones. The analysis of the measurement results allows us to assume that the success
of the project's acoustic quality often depends on the designer's ability to properly assess the design indicators and the properties of applied materials.