bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental design of an active vibration control device used to protect cultural heritage objects.
Authors: Forma Loïc , Wilkie-Chancellier Nicolas , LeConte Sandie , Boutin Henri , Jossic Marguerite
Published: February 2023

While light, temperature and humidity on cultural heritage objects are drastically controlled to assure their better conservation, it is not the case of the vibrations and their impact on the objects have received little consideration. Most of the proposed solutions to protect objects
from vibrations suffer from a lack of adaptability and poor performances in the lowest frequency range. To tackle this issue, the development of a new kind of protection devices based on active control is proposed. The main challenge is to respect the cultural heritage ethics: non intrusiveness
and reversibility. To adapt to a wide variety of cultural heritage objects, the proposed solution aims to minimize the vibrations of a museum's shelf in real time. A replica of museum's shelf is excited by a vibration exciter and a feedforward control configuration is used to monitor the shelf
vibrations, by a reference signal measured on the shelf structure and actuators and error sensors placed on the shelf plate. This bench offers the opportunity to experiment multiple PAA (parameter adaptation algorithms) for which a parameter analysis can be performed. A comparative study based
on criterions such as amplitude attenuation and time convergence is performed to find an optimized control configuration.
Bayesian Optimization Based Adaptive Control of Thermoacoustic Instabilities
Authors: Dharmaputra Bayu , Williner Alain , Schuermans Bruno , Noiray Nicolas
Published: February 2023

Thermoacoustics instability is one of the factors that limits the operational range of gas turbines. Both active and passive control strategies have been developed to suppress thermoacoustic instability. Active control strategies can adapt to the gas turbine's operational condition
and hence provide a wider effectivity than the passive control strategies. However, it remains a challenge to best optimize the control parameters. This work proposes an adaptive control strategy by using Gaussian Process Regression with a modified Safe-Optimisation (SafeOpt) algorithm. The
main benefit of the algorithm is it can safely explore the parameter space and minimize the cost function simultaneously. The performance of the algorithm in suppressing the thermoacoustic instability is experimentally demonstrated by stabilizing a turbulent combustor with loudspeakers actuation.
Research on indoor noise evaluation and renovation design of university library--Taking the library of Wushan campus of South China University of Technology as an example
Authors: Zhang Yang , Wang Hongwei
Published: February 2023

Due to the special use requirements of university libraries, the requirements for indoor acoustic environment quality are relatively high. By investigating the layout and structural design of the library on the Wushan campus of South China University of Technology, distributing questionnaires
to users and conducting on-site monitoring, fiunally found out the problems of the library, such as the sound of the upper and lower floors was connected, noise of friction with the ground when walking, keyboard tapping, moving seats, flipping and rummaging books, air conditioning and ventilation
equipments and the low voice of speech had a greater impact on users, moreovernear the toilet and the elevator was noisy, the actual measurement of the sound level meter showed that the intermittent noise exceeded 55dB (GB 37488-2019 Hygienic indicators and limits for public places stipulates
that the noise limit of the library is 55dB). Based on the above problems, the corresponding renovation measures are put forward, in order to provide technical references for the design and transformation of the acoustic environment of other domestic university libraries.
NVH investigation of automotive HVAC brushless motors
Authors: BENNOUNA SAAD
Published: February 2023

In the automotive industry, thermal systems are of critical importance in securing optimum vehicle operating, preserving battery capacities and ensuring passenger comfort. These systems involve a wide range of components with various technologies, designs and more innovation. Currently,
thermal engine market shares are decreasing as facing increasing electrification trends worldwide. Consequently, thermal systems may become major sources of noise and vibration that may emerge inside the car cabin. This may cause significant discomfort to passengers and can create disturbances
to passersby outside the car. As a system supplier, Valeo ensures NVH compliance according to internal standards and OEM specifications during development and production stages. However, as electrification trends involve more and more innovations with less technical background, ensuring NVH
compliance becomes a formidable challenge to deal with. Among the main NVH sources, the HVAC Brushless motor is highly critical as implanted inside the car cabin. This paper focuses on the main NVH topics encountered on HVAC BLDC motors. First, the NVH sources are analyzed from mechanical
and magnetic design perspectives. Furthermore, solutions to control the NVH behavior are presented which sets the product's intrinsic limitations and operating conditions. Finally, from a technical compliance perspective, specification design implications are discussed.
Cabin noise analysis of an H120 B helicopter for active noise control applications
Authors: Ernst Florian , Sachau Delf
Published: February 2023

Helicopter pilots are exposed to high noise levels during flight induced by the rotor, engine and airflow. To reduce this noise exposure, headsets with active noise control functions are increasingly being used. In addition to the passive noise reduction these systems reduce low frequency
noise by local destructive interference of the sound waves. The development of active noise control systems requires detailed analysis of the acoustic environment, which is rarely available for helicopters. For this reason, sound measurements were taken for different flight parameters on board
an H120 B helicopter. Multiple microphones were placed at the crew and passenger positions and in the center of the cabin. In addition, a head and torso simulator (HATS) was placed in the copilot seat to measure the passive attenuation and the ANC performance of a commonly used commercial
ANC headset in flight. The results of the analysis provide useful information about the noise characteristics for different flight conditions of the H120 B and identify the most critical noise components.
Acoustic search for 'The Witches Valley'
Authors: Lombardi Ilaria , Bevilacqua Antonella , van Tonder Cobi
Published: February 2023

The city of Benevento is famous for the legend of witches as they gathered in a place outside the city and danced under a magical Walnut tree. This legend was resumed in 1639 in Piperno's book "De Nuce Maga Beneventana" which describes this place located in the valley of the
river "Sabato". Another hypothesis states that this legend is due to the invasion of the Longobards (Germans people) during the Middle Ages, as the city was their capital Centre. The Longobards were used to perform rituals dancing under a tree accompanied by the rhythm of drums.
The Longobards selected a place where the sound could be amplified by the natural conformation of the landscape in order to impress the participants. This paper deals with the sound analysis typical of various places located in the valley of the river Sabato. The presence of rocks naturally
amplifies the sound. The acoustic measurements have been performed by using firecrackers and the impulse response was acquired with a Brahma microphone. The acoustic analysis confirms that these places are characterized by a development of sound reflections, a phenomenon that can explain why
a drum roll is perceived as a very reverberant sound.
Emission and propagation of sound waves in porous media with active inner heat sources
Authors: Venegas Rodolfo , Boutin Claude , Núñez Gabriel
Published: February 2023

Wave propagation through porous media with active inner heat sources is investigated in this paper. Through the use of the two-scale asymptotic method of homogenisation, it is found that a macroscopic non-homogeneous wave equation describes the emission and propagation of sound waves
in such active porous media. The upscaled model is validated numerically for the cases of single and double porosity media, and shows that the general properties of the effective parameters of the porous media are not altered by the inner heat sources. Instead, the inner heat sources contribute
to the non-homogeneous term in the upscaled wave equation. The paper also explores the potential of using active inner heat sources for controlling sound waves incident to the porous media in practical scenarios.
Exploring the relationship between acoustic environmental quality and civic engagement against environmental noise: Outline of a study design from an equity perspective
Authors: Riedel Natalie
Published: February 2023

Intractable noise exposure has been related to lacking perceived noise control that may deter residents from adopting active coping strategies, e.g. civic engagement against environmental noise. Conversely, environmental stimuli conferring perceived environmental control could be conducive
for cognitive resources relevant for civic engagement. Given unequal noise exposures and coping options, civic engagement and participation in planning processes are crucial for environmental justice, however. Exploring the relationship between acoustic environmental quality and civic engagement
could therefore deliver an intervention point to achieve more environmental justice. In response to local specifics in the City of Münster, this project shall develop a study design that elaborates on (1) residents' controllability perceptions at home and engagement-specific cognitions,
(2) the qualification of 'restorative' as places of behavioural controllability, and (3) the potential compensatory impact of restorative places on uncontrollability perceptions at home and behavioural sequelae. In view of the research objective, the study itself shall contribute to residents'
empowerment, thereby increasing procedural environmental justice. The study design involves information and communication technologies in order to enhance social inclusion. In this contribution, we aim to discuss our study design from an equity perspective and will present preliminary results
of our feasibility test.
Morphology influence on the acoustics of permeo-elastic media
Authors: Boutin Claude , Venegas Rodolfo
Published: February 2023

This paper deals with the acoustics of permeo-elastic media. These media consist of a rigid porous skeleton on which flexible elastic films are fixed and interact with the fluid saturating the pores. They can correspond to foams, the thin membranes playing the role of films and the
rigid structure being formed by the struts. The acoustics of permeo-elastic media can deviate from that of conventional porous media due to the fluid/film interaction at the pore scale. This introduces an elastic component in the energy that interacts with viscous and inertial effects. The
actual behavior is established by the two-scale asymptotic homogenization method. It is shown that the film effects depend strongly on the pores and the film arrangement. Different wave propagation regimes are identified depending on the nature of the local flow. Consider- ing (i) fully connected,
i.e., no pores are closed by the films, (ii) unconnected, i.e., all pores are closed, and (iii) partially connected, i.e., some pores are closed by the films, the study re- veals under which conditions the fluid-film interaction significantly influences the macroscopic acoustic behavior. Depending
on the morphology, the permeability or compressibility (or both) can exhibit singularities or anomalous properties due to inner resonance or anti-resonance.
The challenging measurement of acoustic effect of road surface on truck tyre noise by standard close proximity method
Authors: Lelong Joël , Anfosso Lédée Fabienne
Published: February 2023

The CPX method is an efficient tool for assessing and comparing road surface acoustic properties. For heavy trucks, the standard method ISO 11819-2 requires that noise measurements are also performed with a "pick-up" type of tyre with noise emission characteristics of heavy
goods vehicles, and proposes the tyre "H1". However this tyre does not comply with European regulations since November 2016. The objective of this experiment is to test the Standard Reference Test Tyre SRTT-C2 for light trucks as a replacement. To this end, our CPX trailer was adapted
to the large size of the test tyre. Then, the relevance of the SRTT-C2 to characterize road surfaces acoustically has been demonstrated in previous papers. The current paper presents a complementary study of the representativeness of this tyre, by comparing spectral effect on different pavements
between CPX measurements with the SRTT-C2 tyre and SPB measurements of real trucks in the traffic. Combined SPB and CPX measurements were performed on three road sites, completed by CPB measurements to characterize the transfer function SPB/CPX. The results show that the SRTT-C2 tyre has a
different spectral behaviour from that of heavy trucks (regardless of the number of axles) particularly in low frequencies.
Comparing Acoustic Measurements of Underwater Materials in Pressure Tanks Using a Calibration Panel
Authors: Kasprzak Scott , Craun Matthew , Robinson Stephen
Published: February 2023

Researchers in the United Kingdom and the United States worked together to compare acoustic panel measurement methods and equipment using a calibration test panel. Underwater testing can be used to calibrate various transducers or to measure acoustic properties of materials, from which
material properties can then be derived. The calibration panel used in this study consisted of a rubber material. Tests were initially conducted in the Acoustic Pressure Vessel (APV) at the National Physical Laboratory (NPL) in Teddington, UK and were subsequently performed in the Acoustic
Pressure Tank Facility (APTF) at the Naval Undersea Warfare Center (NUWC) in Newport, Rhode Island, USA. The UK tank is a smaller-scale version of the US tank. However, the measurement approaches developed by the two groups of researchers differs. The UK utilized a parametric source with a
baffle and a planar hydrophone array for reflection and transmission measurements. The US used a spherical source, a linear pseudo-array along with coherent subtraction for reflection, and a single hydrophone for transmission measurements. Early results indicated that the measurement methods
showed significant discrepancies, but refurbishment of the US facility and subsequent re-testing of the panel delivered results that were in good agreement between the two groups.
A Multiple Target Data Association Method for TDOA Passive Localization
Authors: Feng Miao , Gu Zhaoning , Fang Shiliang
Published: February 2023

In order to solve the multiple target data association problem in underwater acoustic passive localization system, a new algorithm focus on data association in Time Difference of Arriva l(TDOA) is studied. Firstly, the zero-sum condition is used to select TDOA measurements according
to the continuous measurement values within a certain period of time. Then, the selected TDOA measurements are associated with the multiple targets and the correct correlation probability is measured by the correlation degree. The algorithm is used in sea trial. Processing results show that
the method proposed in this paper can effectively solve the TDOA measurement association problem, and can locate multiple targets at the same time.
A general stable approach to modeling and coupling multilayered systems with various types of layers
Authors: Song Guochenhao , Mo Zhuang , Bolton J. Stuart
Published: February 2023

In this article, a general method is proposed to model layered systems with two-by-two transfer matrices, and further, to solve for the acoustic absorption, reflection, and transmission coefficients. Since the proposed method uses the matrix representation of various layers and interfaces
from the Transfer Matrix Method (TMM), the equation system can be established efficiently. However, the traditional TMM can lose stability when there is a large disparity between the magnitudes of the waves traveling in opposite directions within the layers (i.e., at higher frequencies, for
a thick layer, or for extreme parameter values). In such cases, the contribution of the most attenuated wave can be masked by numerical errors and can induce instability when solving the system. Therefore, in the proposed method, to stabilize the calculated acoustic properties of the system,
the principle is to ensure the accuracy of the wave attenuation terms by decomposing each layer's transfer matrix and reformulating the equation system. This method can couple different layer types in a general way and is easy to assemble and implement with numerical code. The predicated acoustic
properties of layered systems calculated using the proposed method have been validated by comparison with those predicted by other existing methods.
Using clustering methods to detect quality data in a smartphone-based crowd-sourced database for environmental noise assessment
Authors: Boumchich Ayoub , Picaut Judicaël , Bocher Erwan
Published: February 2023

Environmental noise is a major source of annoyance with serious effects on health. Therefore, noise assessment is crucial to reduce these impacts. An alternative approach has been developed (i.e. noise measurement with smartphones) to overcome the limitations of classical assessment
methods (e.g. simulation tools or noise observatories). In this way, the NoiseCapture application consists of measuring and sharing data, in order to produce community noise maps. Nevertheless, collected data may suffer from problems such as a lack of calibration, which lowers its quality.
Quality control is therefore very important to enhance the data analysis and the relevance of the noise maps. Having trustworthy data as a reference can help in assessing the database, for example using machine-learning methods. WIth NoiseCapture, such data can be collected thanks to a NoiseCapture
Party, an organized event, on limited space/time (i.e. a cluster of data). Because not all events are known by the people in charge of NoiseCapture, and since the corresponding data can be considered of better quality, so their detection is a relevant task to increase the trust database. In
the present communication, a clustering methodology is then proposed to automatically detect data that could be produced in such events.
Engine Order Cancelation in a super sports car cabin
Authors: Ferrari Cesare Lupo , Cheer Jordan
Published: February 2023

Active noise control (ANC) has been used in several systems to improve acoustic performance while avoiding increases in the size and weight required by passive noise control solutions. This paper considers an ANC application aimed at controlling the sound field in the cabin of a supersports
car with a naturally aspirated engine. This work studies the performance of a system that employs microphones and loudspeakers in the car cabin and uses a reference signal obtained from CANbus data. The controller exploits a multichannel, multi-order Fx-LMS algorithm to control the sound only
in the region surrounding the driver's ears. Due to the nature of the car, this ANC application provides an interesting and challenging case study due to the rapidly changing acoustic excitation provided by the engine. The paper therefore describes a system for noise reduction, focusing on
engine order reduction, aiming at achieving control during the most representative manoeuvre known as the "Wide-Open Throttle" (WOT). The investigated controller - acting locally and only on some orders simultaneously - shows good sound attenuation over the entire spectrum, with
peaks of reduction exceeding 10 dB, and achieving a 5% overall decrease in the loudness, which is calculated according to ISO 532-1.
Evaluation of the renovation of an urban highway viaduct using citizen science low-cost noise monitoring
Authors: Dekoninck Luc
Published: February 2023

A main highway in Belgium (E17) has transected the city of Ghent with a viaduct since 1970. This highway is the main north-south artery for heavy traffic from and to the ports of Antwerp and Rotterdam. The viaduct has significant maintenance issues and was subjected to multiple noise
control actions in the past. Since 2014 a local citizens initiative named 'Viadukaduk' -mimicking the sound of the viaduct to allow public engagement in resolving the environmental issues. In 2020, a major renovation was initiated. Prior to this renovation (in 2015) noise measurements were
performed at two dwellings at either side of the viaduct. In 2020, at the beginning of renovation, measurements were repeated at the two dwellings. Post-renovation, the two datasets, 2015 and 2020/2022, have been used to perform a noise evaluation due to the renovation of the viaduct, including
the impact of changes in noise barrier type, road surface and bridge joints. Preliminary results show a change of 7 dBA, although at the impact of the renovation itself is limited to 1 dBA. The data collected during the renovation illustrate the different phases: speed reduction and lane changes,
removing old screens, placement of new screens, refurbishing bridge joints etc.)
Guidebook: how to reduce noise annoyance from road traffic
Authors: Bendtsen Hans , P. Volk Christer , Holm Pedersen Torben , Eggers Sebastian , Gjestland Truls
Published: February 2023

The objective of the FAMOS project was to develop a European guidebook with practical applications for the National Road Administrations on how to handle noise annoyance by non-acoustic moderators in planning of roads. When all technically feasible and economically possible measures
to reduce the noise have been used, there can still be need for further reduction of the annoyance. Analyses reveal that only 1/3 of the variance in the annoyance response is caused by the noise level. 2/3 are determined by so-called non-acoustic factors. The annoyance response therefore can
be altered without changes to the actual noise level. The project searched moderators that have a large impact on the annoyance without changing the noise level. The search was an international literature survey on annoyance studies. Moderators found were: •Expectations to and visual
appearance of noise barriers •Presence of vegetation/greenery •Access to a quite façade •Neighbourhood soundscape •Attitudes towards authorities and road owners •Perceived traffic safety Experimental tests using sound walks, questionnaires and listening tests
have been performed to quantify some moderators. Various methods have been used to find, extract and analyse data and turn the results into models for moderators formulated for practical use.
Active nonreciprocal structural control on a flexible plate
Authors: Tan Joe , Cheer Jordan , Daley Steve
Published: February 2023

Reciprocity is an acoustic property that describes the symmetry of sound transmission between two points. However, this property is undesirable in certain applications, and this has led to significant interest in the development of nonreciprocal acoustic devices that achieve one-way
sound transmission. These devices typically achieve nonreciprocal sound transmission by introducing nonlinearities or directional biasing. Previously proposed nonreciprocal acoustic devices generally have limitations; for example, they may not be fully adaptable, they can introduce signal
distortions such as additional harmonics, or they can only exhibit nonreciprocal behaviour over a narrow bandwidth. To overcome these challenges, previous work has demonstrated how an wave-based active control system can be used to drive an array of acoustic sources to achieve reversible and
broadband non-reciprocal behaviour. This paper aims to extend this concept to a linear wave-based active structural-acoustic control system that uses an array of structural actuators to control the individual wave components to achieve broadband nonreciprocal transmission through a flexible
plate in a three-dimensional environment. The performance of the wave-based active controller has been investigated at a range of incident angles and the limits of this controller have been identified.
Optimizing the performance of a side-branch array duct muffler
Authors: Tang Shiu , Yu Ho
Published: February 2023

Recent studies of the authors show that muffler formed by putting together narrow side-branches in array form can offer strong and broadband sound attenuation in low Mach number flow ducts. It is also found that such muffler with the increasing branch length in the direction of duct
flow has stronger resilience to flow excitation and thus can maintain its sound attenuation performance unless the duct flow is high. However, the arrangement of the branch length has not been optimized. Numerical investigation is carried out using finite-element computation in the present
study to further understand how the branch length variation is affecting the overall sound attenuation of the side-branch array muffler. For simplicity, a branch length variation is assumed to follow a power law of the branch order. A power law index of 1 represents linear variation. It is
found that for a muffler with 11 side-branches, the index for minimum transmission is about 1.5, but that for maximum particle kinetic energy is around 1.38. In term of noise attenuation spectrum, the muffler with index 1 and 3 give very strong attenuation at particular frequencies, while
that with index 1.5 gives a more uniform attenuation within the operation frequency range.
Application of in-situ blocked forces for characterising structure borne vibration of heavy industrial machinery
Authors: Cabaret Florian , McCormick Jacob , Samami Kian , Farrell Oliver , Elliott Andrew , Meggitt Joshua
Published: February 2023

Industrial machinery can generate excessive vibration, potentially reducing their productivity and disturbing their surroundings. Thus, it is essential to control vibration in industrial environments and accurate predictions are required to adopt mitigation measures in the initial design
stages. It is first necessary to perform measurements on the vibration source to characterise its operational behaviour, and the obtained properties can be expressed in terms of its blocked forces according to ISO 20270:2019. The data can be obtained from the source mounted on a specific receiver,
but still deliver intrinsic quantities that remain valid for any different receiver structures. Although good agreements have already been achieved between predictions and on-board validations from light weight structures, proving the theory is well understood, it has not yet been applied
effectively to heavier assemblies which will be the focus of this work. A source characterisation case study is presented in this paper for a typical heavy industrial installation known as a press softly mounted on an inertia block isolated from the surrounding factory floor. A description
of how the passive properties of the press were obtained and vibration predictions at different positions of the coupled assembly will also be given.
Vehicle pass-by noise auralization in a virtual urban environment
Authors: Dreier Christian , Vorländer Michael
Published: February 2023

Auralization is a suitable method for the subjective evaluation of environmental noise. Due to its complexity, the plausible and immersive acoustic representation of outdoor scenarios in urban environments is an ongoing field of research. This work presents the design and implementation
of a vehicle pass-by noise model with application in a real-time environmental noise auralization. The pass-by noise sources are implemented by procedural audio syntheses of engine and road-tyre noise with according directivities. In an audiovisual demonstration, the resulting source model
is auralized considering the sound propagation phenomena in a virtual urban environment using the Virtual Acoustics framework.
Acoustic assessment of an open-plan office environment against the newly published ISO 22955 acoustic parameters
Authors: Batista Michel
Published: February 2023

This paper aims to assess the acoustic performance of an existing open-plan office environment with suspended sound absorbers below a hard reflective ceiling and low workstation dividers against the newly published ISO 22955 acoustic parameters. The room acoustic variables, such as
sound absorption, screens between workstations, speech masking sounds and room dimensions all interact in a complex way affecting the values of single-number quantities presented in the ISO 22955 standard. In order to determine the in-situ performance, acoustic measurements were carried out
on site. Odeon room acoustic prediction software was utilised to assess the efficiency of various acoustical remedies such as free hanging sound absorbers, wall to wall sound absorbing ceilings, dividers between work areas and increased height of dividers between workstations. The results
from the in-situ room acoustic measurements demonstrate that the required value as described in the ISO 22955 standard is not easily achievable in the open-plan office environment without dividers with sufficient height between workstations and modest room acoustic features. The acoustic modelling
results confirmed that the required level for the open-plan office, in terms of the ISO 22955 standard, is only attainable with a combination of room acoustic variables that go against modern interior designs.
Bias-aware thermoacoustic data assimilation
Authors: Novoa Andrea , Racca Alberto , Magri Luca
Published: February 2023

Ensemble data assimilation algorithms combine experimental data and numerical models to estimate the state and parameters of a system. If the model is unbiased, the estimation concentrates around the true state. Thermoacoustic instabilities are, however, commonly modelled with low-order
models, which are biased by definition. We propose the introduction of reservoir computing to represent the model bias. We combine the ensemble square-root Kalman filter with an echo state network to perform, in real time, (1) the estimation of the state of the system, (2) parameter calibration,
and (3) model bias estimation. The proposed methodology is tested in a Rijke tube system, with synthetic experimental data from a high order model.
Speech perception and deaf and hard of hearing children in the classroom: A multidisciplinary effort in the United States to bring data and standards to architects, school districts, and into building codes
Authors: Iglehart Frank
Published: February 2023

This presentation will discuss efforts by a multidisciplinary team to overcome the notable lack of progress in the United States in acoustic accommodations for deaf and hard of hearing children in the classroom. Data collected through research efforts by members of this team, and by
others, demonstrate the benefits of appropriate acoustics for all children and especially those deaf and hard of hearing. These efforts have resulted in a voluntary standard in classroom acoustics specifically for deaf and hard of hearing children by the American National Standards Institute.
This standard, however, is not reaching built classrooms. This team representing the fields of acoustics, architecture and audiology is using speech perception data and new computer simulations to increase awareness of the need for classroom acoustic standards in building codes to accommodate
deaf and hard of hearing children.
Effect of Bearing Direction and Mounting Techniques on Cross-Laminated Timber Elements in the Field
Authors: Nilsson Erik , Ménard Sylvain , Bard Hagberg Delphine , Hagberg Klas
Published: February 2023

Vibration reduction index (Kij) measurements in the field have some challenges compared to laboratory measurements. Firstly, the measurement requires access to a construction site during the short time span when the cross-laminated timber (CLT) elements are apparent. Secondly, building
contractors are often on a tight time schedule. Therefore, it is important to find a solution that minimizes the measurement time on site. Moreover, Kij measurements in the field include several types of junctions with different bearing directions which may be of importance. This paper aims
to evaluate two different mounting techniques with accelerometers on CLT elements and to discuss how the bearing direction could affect the vibration level difference of junctions. Measurement data indicates few deviations between mounting techniques with bee wax or double-sided adhesive tape
when accelerometers are attached on CLT elements. Furthermore, field measurements indicate that the vibration level will decrease with an increased number of lamellas over the same CLT element. Double-sided adhesive tape is an adequate substitute for bee wax in the field for mounting accelerometers
on CLT elements, with some limitations for high frequencies. Measurement data concludes that the bearing direction of CLT elements can influence the vibration reduction index of a junction.
Acoustic and aesthetics: The effect of paint on fabric backed by a sound absorber
Authors: Diaz Mena Angela Marion , Aygun Haydar
Published: February 2023

This project investigates the effects of paint on the acoustic properties of the cotton and canvas fabrics. Polyurethane foam was used to back the fabric, and the dependencies on the type of paint, painted area, area distribution, and the type of fabric were analysed. One hundred and
nine samples of cotton and canvas fabrics were used for this investigation. The impedance tube method, which is performed via the transfer function method, was employed to determine the acoustic properties. It is shown that the absorption of the samples is affected by the type of paint and
fabric, and painted percentage area, and establishing an effective set of these parameters will result in the acoustic transparency of the fabric.
Acoustic effects of elevated platforms for standing audiences in an indoor music venue
Authors: Sánchez Rebeca , Gomez-Agustina Luis
Published: February 2023

The live music industry has grown significantly over the last decade, making live music not only an important component of the cultural scene but also a major economic engine. There is little research or guidance regarding acoustic design for amplified music venues, especially for improvements
in the design of the indoor standing audience area. This investigation aimed to determine the acoustic effects and potential benefits to the audience, of elevated platforms in an indoor music venue. Objective parameters such as reverberation (T30), Early Decay Time (EDT), Clarity (C80), Definition
(D50), and Sound Pressure Levels (SPL) were analysed through computer simulations for twelve platform arrangements of different platform heights and audience densities. Results from all possible combinations were compared and evaluated for improved acoustical and sound quality. It was shown
that the use of elevated platforms reduced reverberation time parameters and increased C80 and D50. These changes in acoustic parameters appeared also to be dependent on audience density. It is expected that the novel information and guidance provided by this research will assist acoustic
designers, sound engineers, and other relevant decision-makers to improve the audio-visual experience of standing audiences.
Basic study on voice evacuation guidance system using precedence effect in virtual space with wall reverberation
Authors: Daimon Takeru , Osumi Ayumu , Ito Youichi
Published: February 2023

We have studied voice evacuation guidance system using a precedence effect, which was a psychoacoustic effect. This system can be realized rapid evacuation to the safety area in the environment with poor visibility such as smoke and dust, because it uses voice announcements to guide
evacuation. A basic design of construction of sound space suitable for the system and sound adjustment in the field, such as speaker position and sound pressure level setting is required, when applying this system to a building. In this research, we propose to support the basic design for
constructing the above system by using VR (Virtual Reality) technology. If the basic design can be performed in the virtual space using VR technology, the time required for the design can be significantly reduced, because there is no need to experimentally design. In this report, we constructed
a virtual space that reproduced the wall reverberation in the real space, and compared the evaluation characteristics of the preceding sound effect between the real space and the virtual space. As a result, we confirmed that we could obtain the same level of evaluation characteristics of precedence
sound effect in real and virtual spaces.
Diesel Engine Noise Source Visualization by Using Compressive Sensing Algorithms
Authors: Shi Tongyang , Bolton J. Stuart , Eberhardt Frank
Published: February 2023

To identify sound source locations by using Near-field Acoustical Holography (NAH), a large number of microphone measurements is generally required in order to cover the source region and ensure a sufficiently high spatial sampling rate: it may require hundreds of microphones. As a
result, such measurements are costly, a fact which has limited the industrial application of NAH to identify sound source locations. However, recently, it has been shown possible to identify concentrated sound sources with a limited number of microphone measurement based on Compressive Sensing
theory. In the present work, sound radiation from the front face of a diesel engine was measured by using one set of measurements from a thirty-five-channel combo-array placed in front of the engine. The locations of significant noise sources were then identified by using two algorithms: i.e.,
l1-norm minimization and a hybrid approach which combined Wideband Acoustical Holography (WBH) and l1-norm minimization. It was found that both algorithms can successfully localize and visualize the major noise sources over a broad range of frequencies, even though using a relatively small
number of microphones. Finally, comments are made on sound field reconstruction differences between the two algorithms.
Design, construction and commissioning of a reverberation room
Authors: Pearse John , Healey Aaron
Published: February 2023

In this paper we discuss the design, construction and commissioning of a reverberation room that meets the requirements of ISO 354:2003. The new room was built using lightweight double walls rather than the more usual monolithic construction. We present an analysis of measurements made
during the commissioning of the room and discuss these results; these measurements include the effect of adding various diffusing elements, lighting and heating. We made measurements of the sound absorption coefficient of different materials in the commissioned room and these are compared
with measurements of the same materials in two other reverberation rooms that also comply with the requirements of ISO 354:2003.
Method for estimating aircraft noise corresponding to changes in thrust and speed during start of takeoff roll
Authors: Nakazawa Toshiyasu , Shinohara Naoaki , Hanaka Kazuyuki
Published: February 2023

In aircraft noise calculation by international guidelines such as ICAO Doc.9911, NPD (Noise Power Distance) data that relates aircraft thrust and noise are used. In these guidelines net-thrust use as power in NPD data. However, net-thrust of an aircraft engine cannot be measured directly.
Therefore, net-thrust has to be estimated using the conversion equation with engine parameters such as N1% RPM and EPR, as well as speed. Meanwhile, for recent aircraft types, the coefficients for the N1% and speed terms of the conversion equation are not available. For this reason, Japanese
aircraft noise models use N1% and EPR directly in place of net-thrust to create NPD. These parameters change the most at the start of the takeoff roll, and it is necessary to confirm the validity of the noise calculation in this area. In this study, noise measurements at the side of the runway
and aircraft onboard data were analyzed to investigate an alternative method of estimating noise changes to net-thrust. The result shows that it is reasonable to correct the noise according to the speed change in addition to the noise calculation in the section of lower speed state of takeoff
roll.
Deployment of an IoT System for Adaptive In-Situ Soundscape Augmentation
Authors: Wong Trevor , N. Watcharasupat Karn , Lam Bhan , Ooi Kenneth , Ong Zhen Ting , Andi Karnapi Furi , Gan Woon Seng , Yeong Samuel , Lee Irene
Published: February 2023

Soundscape augmentation is an emerging approach for noise mitigation by introducing additionalsounds known as "maskers" to increase indices like acoustic comfort. Traditionally, the choice of maskers is oftenpredicated on expert guidance or post-hoc analysis which can be time-consuming
and sometimesarbitrary. Moreover, this often results in a static set of maskers that are inflexible to the dynamicnature of real-world acoustic environments. Overcoming the inflexibility of traditional soundscapeaugmentation is two-fold. First, given a snapshot of a soundscape, the system
must be able to select anoptimal masker without human supervision. Second, the system must also be able to react to changesin the acoustic environment with near real-time latency. In this work, we harness the combinedprowess of cloud computing and internet-of-things (IoT) to allow in-situ
listening and playback usingmicrocontrollers while delegating the computationally expensive inference tasks to the cloud. Inparticular, a serverless cloud architecture was used for inference, ensuring near real-time latencyand scalability without the need to provision computing resources.
A working prototype of the systemis currently being deployed in a public area experiencing high traffic noise, as well as undergoingpublic evaluation for future improvements.
Validation of calculation method of road traffic noise behind building complex in ASJ RTN-Model 2018 by field measurements
Authors: Sakamoto Shinichi , Xu Wenrui , Fukuda Taiki , Yonemura Miki
Published: February 2023

Road traffic noise calculation method behind the buildings included in the ASJ RTN-Model 2018 is an empirical model formula based on experimental results of a scale model. Therefore the scope of the calculation method is formally limited in terms of building height, density, and distance
from the road, dependent on the range of experimental conditions. However the roadside conditions in Japanese urban and suburban areas are diverse and it is necessary to quantitatively investigate the validity of the calculation in such various conditions in order to widely expand the applicability
of the calculation method. The authors have been studying an efficient estimation method of road traffic conditions in a viewpoint of noise emission from the roads. In order to create accurate noise maps, continuing from the study, an accurate estimation method of noise propagation in various
build-up areas is expected. Therefore, in this study, we examine the validity of the road traffic noise calculation method in building complex by comparing the actual measurement results in some build-up areas around arterial roads.
A time delay estimation approach with low computational complexity for speaker localization
Authors: Song Bangguo , He Hongsen , Yang Tao
Published: February 2023

Time delay estimation (TDE), which aims at estimating the time difference of arrival using the signals captured by an array of microphones, plays an essential role in hands-free speech communication systems for localizing and tracking speakers. The sparse linear prediction model, which
is based on the l1-norm optimization with respect to the prediction-error vector and the coefficient vector of the linear predictor, can be effectively used to prefilter the microphone signals so as to establish a time delay estimator robust to background noise and reverberation. In the course
to solve this model, however, a high-dimension cross-correlation matrix has to be inverted, indicating that the corresponding TDE algorithm has huge computational load. In this paper, we propose a new solution approach to this dual l1-norm optimization model. The original prediction-error
filter is decomposed by Kronecker product into two short subpredictors. Accordingly, the size of the cross-correlation matrix in the TDE algorithm is degraded, which significantly reduces the computational complexity for prewhitening microphone signals. Simulation experiments in room acoustic
environments demonstrate the computational efficiency of the proposed TDE algorithm as well as its estimation precision.
Design of causal preconditioning filters for adaptive filtering algorithms in real-time multi-channel active noise control applications
Authors: wang yiming , Zhuang Yongjie , Liu Yangfan
Published: February 2023

Least-mean-square (LMS) algorithm has been widely used in the area of active noise control (ANC). One practical concern of LMS-based algorithms is its slow convergence rate in multi-channel broadband noise control applications. To improve the convergence speed of traditional LMS algorithm,
preconditioning filters were added to the LMS system in previous studies to remove the correlation between the reference signals and decouple the plant responses. However, the preconditioning filters implemented previously are usually obtained through singular value decomposition of the cross
spectral matrix of reference signals and the plant response matrix, which does not lead to causal preconditioning filters and, thus, it can only be applied in spatial audio applications when delay is not an important concern, but cannot be implemented in real-time active noise control applications.
In the current work, a method is proposed to obtain a casual multi-channel preconditioning filter for real-time active noise control applications through a numerically robust algorithm to perform a spectral factor decomposition to the reference signal cross spectral matrix and a minimum-phase
and all-pass decomposition to the multi-channel secondary path. Simulation results show that, by applying the proposed preconditioning filter, the convergence speed of the LMS algorithm can be significantly improved.
Sound fields characteristics of a box-type CLT building for heavy-weight impact sources
Authors: Kim Yong Hee , Won Dae-gwan , Oh Gyu-in , Koo Bon-su , Lee Jang-won , Kim Sejong
Published: February 2023

This study investigated the effects of interior finishing materials on sound fields characteristics of a box-type CLT building to minimize room responses for heavy-weight impact sources. According to the requirements on ISO 10140-5, the sound fields should have reverberation time (RT)
range between 1 s to 2 s with minimized deviation. Therefore, grid-type sound absorbers, reflectors and diffusers with size of 0.6 m by 0.6 m were designed and applied to the box-type building. The building has a volume of 53.8 m3, and RT of the current condition with no absorbers or diffusers
was 2.56 s at 63 Hz, 1.26 s at 4 kHz. The experiments were carried out with various combination of absorbers and diffusers on lateral walls. As results, it was derived at the case of 44 reflectors with additional 4 bass traps as the optimum sound fields condition. In addition, sound fields
variation as functions of interior finishing materials was discussed for driving heavy-weight impact sources such as bang machine.