bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoacoustic medical imaging demonstration using a pulsed LED
Authors: Burge Leah , McKenna Lauryn , Korman Murray
Published: September 2021

This demonstration of photoacoustics involves a focused light-emitting diode (LED) pulse (620 nm wavelength) which illuminates an optically absorbing target. The rapid expansion generates an ultrasonic pulse detected by an immersion transducer. An LED is a cost-effective alternative
to the traditional neodymium-doped Yttrium-Aluminum Garnet (Nd:YAG) laser and laser diode- that is most effective in near-infrared. The LED is driven by a home-made MOSFET driver capable of 100 A pulses. Focused pulses illuminate a horizontal 1.2 mm capillary tube filled with Fast Green Dye.
A highly-diffuse Teflon cylindrical cavity (9 cm tall, 6 cm diam) contains the mounted capillary tube. A 2.25 MHz immersion transducer with four low-noise amplifier gain blocks (combined 86 decibel gain, 0.5- 30 MHz bandwidth), detects a time-averaged signal from over 1000 trials. Comparisons
are made using India ink. Earlier, T. J. Allen and P. C. Beard used 35 percent hematocrit blood in a capillary tube at a 620 nm wavelength demonstrating the feasibility of photoacoustic medical imaging of vascular systems under the skin or shallow-tissue cancerous tumors (using tomography)
as an alternative to radioactive medical imaging. Our work precedes a photoacoustic tomography demonstration using three targets in an open acrylic tank.
Determination of tonal signal parameters based on zero crossing detection
Authors: Luczynski Michal , Brachmanski Stefan , Dobrucki Andrzej
Published: September 2021

This paper presents a method for identifying tonal signal parameters using zero crossing detection. The signal parameters: frequency, amplitude and phase can change slowly in time. The described method allows to obtain accurate detection using possibly small number of signal samples.
The detection algorithm consists of the following steps: frequency filtering, zero crossing detection and parameter reading. Filtering of the input signal is aimed at obtaining a signal consisting of a single tonal component. Zero crossing detection allows the elimination of multiple random
zero crossings, which do not occur in a pure sine wave signal. The frequency is based on the frequency of transitions through zero, the amplitude is the largest value of the signal in the analysed time interval, and the initial phase is derived from the moment at which the transition through
zero occurs. The obtained parameters were used to synthesise a compensation signal in an active tonal component reduction algorithm. The results of the algorithm confirmed the high efficiency of the method.
Development of Dash insulation with PU elastomer based sound insulation materials for increasing the sound insulation performances of electric vehicle noise derived from motor
Authors: Yu Minji , Park Jang-Seok
Published: September 2021

At present, fuel efficiency improvement technologies for example weight, engine efficiency improvement, design modification, and eco-friendly car are being proceed due to the tightened international regulations. Therefore, production of eco-friendly cars specially electric car has increased.
Due to that, the main noise source has changed from engine to motor noise and road noise as it has been changed from engine cars that have led engine technology to eco-friendly cars. As the noise source has changed, it is necessary to manufacture sound absorption/insulation structure for the
noise characteristics generated by electric vehicles. In this work, the elastomer sheet was applied to the Dash outer as automotive terior parts for reducing engine noise. We applied the elastomer sheets for generation Dash outer layers (nonwooven/PU foam/nonwooven) to improve sound insulation
properties. The elastomer sheet showed surface wetting between PU foam and elastomer sheets by optical microscopy. The acoustic properties were measured by APAMAT-II and BUCK tests.
Acoustic analysis of snoring sound from different microphones
Authors: Yao Yuhe , Zhu Jiecheng , Guo Shaowei , Liu Wei , Ding Li , Peng Jianxin
Published: September 2021

Snoring is a common symptom of obstructive sleep apnea-hypopnea syndrome. The results show that there are obvious differences for most microphones in terms of the data distribution of features in the time and frequency domain. The results of snoring analysis from different recordings
devices would be totally divergent. In view of this, when developing snoring analysis devices based user selected microphones (i.e. smartphone) recorded, we should take into account the discrepancy between different microphones.
Sound quality evaluation for luxury refrigerator door closing sound
Authors: Imamori Kanta , Yoshiga Atsuya , Yoshida Junji
Published: September 2021

In this study, we carried out subjective evaluation tests employing 19 refrigerator door closing sounds to quantify the luxury feeling. By applying factor analysis to the subjective evaluation results, the sound quality of the refrigerator door closing sound was found to be expressed
by the following two factors: overall loudness and the pitch of the sound. Subsequently, luxury feeling evaluation model was obtained through multiple regression analysis. As the result, the luxury feeling of the door closing sound was evaluated to be high when the sound was softer and had
lower pitch. Then, we prepared several luxury door closing sounds according to the obtained evaluation model through a filter processing and conducted subjective evaluation tests again to verify the evaluation model. The result shows that the amplitude increased sound at low frequency band
under 100 Hz, which was calculated to be high luxury by the evaluation model, was actually evaluated as the best among the presented sounds through the subjective test. And the luxury sound quality evaluation method was confirmed to be useful to quantify and estimate the sound quality of the
refrigerator door closing sound.
Experimental study of wavy trailing edge serrations on flat rotor blades
Authors: Kaja Sai Manikanta , Srinivasan K. , Kumar A. Jaswanth Kalyan
Published: September 2021

A detailed experimental study is conducted to observe the effect of various parameters like wavelength, depth of serrations, and pitch angle on serrated blades' acoustic emissions at low speeds up to 2000 rpm. Experiments are conducted on flat blade rotors with sinusoidal serrations
on the trailing edge of blades with different amplitudes and wavelengths. A total of 7 blades with different serration configurations, including a base configuration, are studied, five of them have serrations throughout the span of the blade, and one configuration has serration of varying
amplitude on the farther half of the blade. It is observed that some blade configurations have resulted in tonal noise reduction noise as much as 8dB, whereas some of the serration configurations reduce very little to none, there is no significant effect of T.E serrations on the broadband
noise emitted by the rotor. Directivity of noise generated from the rotor, the effect of serrations on the directivity of the noise is studied.
Numerical simulation of air inlets sound insulation
Authors: Puig Julien
Published: September 2021

Breathing healthy air at home requires efficient ventilation which is generally achieved by mechanically controlled ventilation systems. However, the installation of air inlets, at the top of windows, reduces sound insulation. Actually, laboratory tests must be processed by manufacturers
to measure the SRI (sound reduction index), which is calculated from the difference between the source and receiving sound power levels in the one-third octave band. The addition of melamine, a widely used porous material with interesting acoustic properties, slightly decreases the transmitted
noise through air inlets, but the sound reduction remains far from that of a window without any inlet at all. Moreover, experimental settings induce uncertainties, particularly when low frequencies are involved. Numerical simulation is thus an interesting alternative for studying air inlets'
vibro-acoustic behaviour. Many parameters can be considered without the need to carry out new experiments, thus greatly reducing financial costs. Calculations must be computationally efficient to enable an optimization approach. To this end, the proposed numerical model is based on the patch
transfer function method which is a substructuring approach. Here, each subsystem of complex geometries is discretized by finite elements while porous materials are modelled using an equivalent fluid or localized impedance.
Free vibration analysis of rectangular plates with arbitrary elastic boundary conditions
Authors: Wan Zhenshuai
Published: September 2021

boundary conditions are In this paper, an improved Fourier series method is presented for the free vibration analysis of rectangular plates with arbitrary elastic conditions. The stiffness value of the restraining springs is determined as required to simulate the arbitrary elastic boundary
conditions. The exact solution of plates with arbitrary elastic boundary conditions is solved by the introduced supplementary func-tions. The matrix eigenvalue equation of plates is derived by using boundary conditions and the governing equations. Compared with exist methods, the presented
method can be easily applied to most of plate vibration problems with different boundary conditions. To validate the accuracy of the presented method, numerical simulations with different boundary conditions are presented.presented.
Influence of steering vibration on vehicle speed recognition and comfortableness in cabin.
Authors: Yoshioka Eiji , Itou Shin , Yoshida Junji
Published: September 2021

In recent years, electric vehicles are becoming more popular. This transition makes interior noise and vibration smaller according to the engine rest and makes interior more comfortable. On the other hand, this reduction has a possibility to decrease important information for drivers.
In this study, we focused on the steering vibration as the vehicle speed information and investigated the influence on the comfortableness in cabin for the compatibility through subjective evaluation test using a simple driving simulator. In the test, vehicle speed controlling task was given
to the participants without speed meter at acceleration conditions. In addition, subjective evaluation about the comfortability to the presented sound and vibration was conducted after the speed recognition test. As the presented steering vibration, the following four patterns were prepared.
1: internal combustion engine noise and vibration with road and wind noise (background noise), 2: electric-powered vehicle noise without vibration (background noise without vibration), 3: tire vibration with background noise, 4: motor vibration with background noise. As the result, the steering
vibration of internal combustion engine or motor was found to be suitable stimuli for compatibility between the speed recognition performance and the comfortability in cabin.
Health impact assessment of road traffic noise in the EU in 2020-2035
Authors: Salomons Erik , Dittrich Michael
Published: September 2021

The negative health effects of road traffic noise in the EU are analyzed over the period 20202035. For a baseline scenario, with autonomous traffic growth and fleet development, it is found that the EU health burden in 2030 is equivalent to the loss of 1.7 million 'healthy life years'.
Various noise abatement scenarios are analyzed, with noise solutions such as quiet road surfaces, quiet tyres, and electric vehicles. The health benefits of the scenarios are calculated as healthburden differences from the baseline scenario. The calculation methodology is based on the noise
exposure distributions reported in 2017 by EU member states, for urban agglomerations and for major roads. Changes in noise exposure are calculated with EU model Cnossos for vehicle emission, considering different types of roads (residential streets, main roads, motorways,...). The monetized
health benefits are used as input for a costbenefit analysis of the scenarios over the period 2020-2035. For quiet tyres, for example, high health benefits and low costs are found, resulting in a high cost-to-benefit ratio. This work was part of a study for the European Commision, exploring
different options for reducing the EU health burden caused by noise from road, rail, and air traffic.
Design and simulation of acoustics for the home theatre
Authors: Zhu Liying , Zhao Junjuan , Li Xianhui , Zhang Bin , Wang Yueyue , Wang Wenjiang , Liu Yunan
Published: September 2021

As a typical acoustics room, the sound quality of home theatre is an important standard to evaluate its design. Qualified acoustics design is the guarantee of good sound quality. The volume of home theatre is generally small, so the room size is similar to the low-frequency wavelength.
Then the resonance will occur when the excitation of the sound source frequency acts on the natural resonance frequency of the room. At the same time, the secondary reflection of the room also interferes the direct sound emitted by the speaker, thus destroying the sound image. In order to
solve the above problems, this paper took a home theatre as an example, analyzed the normal modes of the room by the theory of wave acoustics, and then made an acoustics design and simulation. The simulation results showed that the reverberation time was up to the relevant standards and the
room acoustic quality environment was improved obviously after the acoustic design.
An experiment on the feeling of separation when multiple aircraft noises are overlapped
Authors: Morinaga Makoto , Matsui Takanori , Kuwano Sonoko , Namba Seiichiro
Published: September 2021

In order to calculate the A-weighted single event sound exposure level () of aircraft noise, the following method is described in the manual for aircraft noise measurement in Japan. Firstly a time-section, which is the range between two points where the noise level is 10 dB lower than
the maximum noise level (), should be identified, and secondly the energy within the section is integrated. This method can easily be applied to the single event noises. When multiple aircraft noises are overlapped simultaneously, there are cases where cannot be calculated adequately by this
method. In such cases, it is required to record the number of aircraft noises in the field measurements. However, even in the case of manned measurement, it is not easy to separate sound sources just by listening to the sound. A pilot study of the psychoacoustic experiment was conducted using
the stimuli where multiple aircraft noises were overlapped in order to find what condition is needed so that multiple aircraft noises were separately perceived. It was suggested that a considerable time interval was needed so that people felt the separation between aircraft noises only with
auditory information.
(Generalized) Bloch mode synthesis for the fast dispersion curve calculation of 3D periodic metamaterials
Authors: Cool Vanessa , Van Belle Lucas , Claeys Claus , Deckers Elke , Desmet Wim
Published: September 2021

Metamaterials, i.e. artificial structures with unconventional properties, have shown to be highly potential lightweight and compact solutions for the attenuation of noise and vibrations in targeted frequency ranges, called stop bands. In order to analyze the performance of these metamaterials,
their stop band behavior is typically predicted by means of dispersion curves, which describe the wave propagation in the corresponding infinite periodic structure. The input for these calculations is usually a finite element model of the corresponding unit cell. Most common in literature
are 2D plane metamaterials, which often consist of a plate host structure with periodically added masses or resonators. In recent literature, however, full 3D metamaterials are encountered which are periodic in all three directions and which enable complete, omnidirectional stop bands. Although
these 3D metamaterials have favorable vibro-acoustic characteristics, the computational cost to analyze them quickly increases with unit cell model size. Model order reduction techniques are important enablers to overcome this problem. In this work, the Bloch Mode Synthesis (BMS) and generalized
BMS (GBMS) reduction techniques are extended from 2D to 3D periodic structures. Through several verifications, it is demonstrated that dispersion curve calculation times can be strongly reduced, while accurate stop band predictions are maintained.
Big Acoustics in Small Spaces - Achieving HS Auditorium Design Goals with Space Constraints
Authors: Tanen Robert , Aquila Alexander M.
Published: September 2021

When designing a high school auditorium there are several factors that determine the outcome of the final construction. Prior to establishing acoustical design goals, the restrictions outlined from the design team typically start at budget and may extend to the size of the box in which
the auditorium is to fit. A fluent balance between design restrictions and internal acoustical goals is critical to create a successful end-product. This case study shows the actions taken to increase the volume, provide custom diffusion, and isolate an auditorium from mechanical sources directly
above the space. Furthermore, critical acoustical metrics such as loudness, spaciousness, ITDG, intimacy, reverberation time, clarity, etc., were analyzed in design and measured post construction. Results, based on ISO 3382-1 testing are provided, as are the noise control measures implemented
to achieve the established set of design criteria. The overall intent of this case study presentation is to exhibit how goals across each design team discipline can be met, through sometimes unwilling compromise, ultimately producing a rewarding end-result for acousticians, architects, engineers,
and ownership.
"The answer is blowin' in the wind" - case study of a perforated roof screen
Authors: Nash Anthony
Published: September 2021

A recently-completed building was fitted with a roof screen fabricated from perforated sheet metal panels having "U"-shaped upturned flanges. When wind impinges on the panels, complex tone clusters are generated, leading to complaints from the occupants. The unusual character
of the tonal spectrum is reminiscent of a film sound effect intended to simulate a hovering extraterrestrial spacecraft. After some preliminary (but inconclusive) field investigations, it was decided to test samples of the perforated panel in a large commercial wind tunnel where the speed
and angle of the airstream could be controlled. Tones generated in the tunnel were found to occur in groups or clusters - these are most pronounced when the airstream's angle of incidence is close to grazing. Gradually increasing airspeed caused the frequency of the tones to "jump"
from one cluster to the next higher cluster. The physical principles of the tone-generating mechanism are not fully understood; however, it appears that structural resonances in the panel flanges are excited by air flowing over the perforate. Some form of a positive structural-acoustical feedback
loop is involved since a) the frequencies within each tone cluster are quite stable and, b) damping the panel flanges extinguishes the tones.
Development of a feedback interface for in-situ soundscape evaluation
Authors: Karnapi Furi Andi , Lam Bhan , Wong Trevor , Ooi Kenneth , Ong Zhen-Ting , Gan Woon-Seng , Hong Jooyoung , Yeong Samuel
Published: September 2021

Studies involving subjective evaluation require feedback from human participants to assess the performance of a system or an environment. A participant is typically presented with a set of metrics to be observed and they present their assessment accordingly. Investigator-led in-situ
soundscape evaluation in ISO 12913-2 collects perceptual responses along with other acoustical and locale information. This is a labor intensive and time-consuming processes. To alleviate and complement investigator-led evaluations, a portable and compact feedback system with an e-ink display
and capacitive buttons was designed, and is undergoing field tests to address the aforementioned requirements. The system employs a low-cost, low-power microcontroller unit (MCU) with necessary hardware interfaces to enable capacitive sensing. Capacitive buttons provide an intuitive interface
and avoid the inherent wear and tear of mechanical buttons. This digitized feedback interface affords the flexibility to synchronize (wired or wirelessly) with a playback system to evaluate an augmented soundscape, and is suitable for both supervised and unsupervised subjective assessments.
Assessment of inter-IC sound microelectromechanical systems microphones for soundscape reporting
Authors: Wong Trevor , Lam Bhan , Karnapi Furi Andi , Ooi Kenneth , Gan Woon-Seng
Published: September 2021

Acoustic parameters obtained from calibrated acoustic equipment are part of the minimum soundscape reporting requirements as stated in Annex A of ISO 12913-2. To dynamically monitor the acoustic environment of a large area, a large network of acoustic sensors could be deployed, albeit
at significant cost. Micro-Electro-Mechanical Systems (MEMS) microphones offer compact, low-cost and high-performance alternatives to traditional analog microphones. In particular, the use of Inter-IC Sound (IS) communication allows MEMS microphones to be conveniently used in concert with
I2S output interfaces for sound actuation. The performance of several IS MEMS Microphones was compared to that of an IEC 61094-4:1996 WS2F microphone in an anechoic chamber and a series of digital filters was designed to compensate for the differences in frequency response. The noise floor,
compensated frequency response, acoustic parameter accuracy of IS MEMS were evaluated and recommendations regarding the suitability of the IS MEMS were provided.
Confusion in the evaluation of sound barriers under harmonized standard
Authors: Rubáš Pavel
Published: September 2021

After the obligatory introduction of the declaration of uncertainty in EN 1793-2:2018, the B categories shall not be used to prevent further confusion. Contrary to the updated standard, B categories remain a ubiquitous contractual criterion in the Czech Republic. Contractors continue
to request insulation category B3 products determined according to the cancelled EN 1793-2:1997. The current standard only specifies a test method for determining the intrinsic airborne sound insulation performance of noise barriers designed for tunnel roads, deep trenches or covered spaces.
EN 1793-6:2018 shall be used for barriers designed for non-reverberant conditions. Notified bodies involved in barriers testing should exercise care and analyze whether supporting test standards in the cancelled but still harmonized EN 14388:2005 can be used or whether the latest testing procedures
will be considered. A guidance document is vital because the situation is becoming increasingly confusing. Common rules should be established across the EU to prevent invalid contractual requirements concerning B3 category barriers designed for non-reverberant conditions. The paper analyzes
the current unsatisfactory situation, discusses the application of single number rating involving uncertainties, and proposes decision rules for logical and illogical contractual requirements.
Simulation of LMS based adaptive noise cancellation using Labview
Authors: Anachkova Maja , Domazetovska Simona , Petreski Zlatko , Gavriloski Viktor
Published: September 2021

The audio signals processed in the signal measurement systems are inevitably susceptible to unwanted noise which significantly affects the quality of the signal and the overall performance of the signal communication systems. Due to its' random and unpredictable nature, the amount of
noise in signals has proven to be a significant issue in designing these systems and recently has been a trending research topic. In this regard, the active noise cancellation method has proven to be an effective technique for eliminating the noise effects on signal processing. The concept
of active noise cancellation is based on the application of adaptive filters and algorithms proposed to reduce the signal corruption and distortion caused by the noise due to the principle of destructive interference. In this paper a simulation model of active noise reduction technique using
the LMS (Least Mean Square) algorithm in Labview is presented. The purpose of the work is to investigate the noise cancellation effect on a recorded audio file in terms of analyzing the audio file before and after filtering out the noise by using the LMS algorithm and discuss the results thereof.
Spatial release from masking in varying spatial acoustic under higher order ambisonic-based sound reproduction system
Authors: Hui C. T. Justine , Hioka Yusuke , Watson Catherine I. , Masuda Hinako
Published: September 2021

A previous study found that spatial release from masking (SRM) could be observed under virtual reverberant environments using a first order Ambisonic-based sound reproduction system, however, poor localisation accuracy made it difficult to examine effect of varying reverberation time
on SRM. The present study follows on using higher order Ambisonics (HOA) to examine how benefits from SRM vary in different spatial acoustics. Subjective speech intelligibility was measured where four room acoustics:reverberation time (RT)= 0.7 s (clarity (C50)= 16 dB, 7 dB); RT= 1.8 s (C50=
8 dB, 2 dB) were simulated via a third order Ambisonic system with a 16 channel spherical loudspeaker array. The masker was played from 8 azimuthal angles (0, +-45, +-90, +-135, 180 degrees) while the target speech was played from 0 degree. The listeners are deemed to benefit from SRM if their
intelligibility scores were higher when the masker comes from a different angle than that of the target. We found while listeners could benefit from SRM at C50 = 16 dB and 8 dB, the benefit starts to diminish at C50 = 7 dB, and listeners could no longer benefit from SRM at C50 = 2 dB.
Acceleration sound design for vehicles using distortion products
Authors: Aburagi Yu , Yamagiwa Natsuki , Tanimoto Noriyuki , Ishimitsu Shunsuke , Matsumoto Mitsunori , Murakami Yasuki
Published: September 2021

When considering the acoustic design of automobiles, low-frequency sounds can increase the excitement levels for users. However, there are several problems accompany an increase in the low-frequency levels of an engine sound. For example, it is difficult to create a balance between
silence and excitement when a sound's different order components are changed. It is also difficult to generate heavy bass engine sounds in practical scenarios. Thus, the application of distortion products in the auditory system of the cochlea is considered. Distortion products are perceived
when two or more sounds with slightly different frequencies are played simultaneously. This study was conducted to examine the possibility of achieving powerful engine sounds using distortion products. At first, the relationship between different combinations of complex sounds and the pitch
perception of distortion products was investigated. As a second step, the application of distortion products to the acceleration sound was also considered. The results suggested the possibility of synthesizing a low-frequency component using distortion products inside a cochlea.
Vibroacoustic analysis of a thin laminated composite plate with surface-boned piezoelectric patches and subjected to general boundary conditions
Authors: Hu Zhengmin , Zhou Kai , Chen Yong
Published: September 2021

In this paper, a semi-analytical model is proposed to deal with the vibroacoustic problems of laminated composite plates with surfaced-boned piezoelectric patches and subjected to general boundary condition using the modified Fourier series method. Based on Kirchhoff plate theory, the
dynamic equation of the laminated composite plate is derived using Hamilton's principle. In order to satisfy general boundary conditions, the displacement solution of the plate is expressed in the form of two-dimensional Fourier series and serval auxiliary functions. The acoustic response
of the laminated composite plate due to a harmonic concentrated force is obtained with the Rayleigh integral. Besides, the mass and stiffness contribution of the piezoelectric patch are taken into consideration in the present study. Through enough convergent studies and comparative studies,
the convergence, accuracy and universality of the proposed method are validated. The developed semi-analytical model can be used for efficient and accurate analysis and design of laminated composite plates equipped with shunted piezoelectric patches. Finally, the effects of the resistor and
inductor shunt damping circuits on the vibration and acoustic response is discussed.
The effects of different ceiling structures and plan typologies on acoustical conditions of historical mosques
Authors: Yelkenci Sert Fatma , Yılmaz Karaman Özgül , Karaman Özgül Yilmaz
Published: September 2021

Mosque is a building type used by Muslim people consists of speech and music rituals. Good acoustical condition in mosques is an important issue to provide desired acoustical environment for prayers and Imams during different worship rituals. Prayers need to feel individuality in praying
and the sense of unity in recitation of the Quran, hymns. Worship activities need a high level of speech intelligibility and to satisfy prayers in the spiritual aspects which make people feel closed to the God. In the context of study, six historical mosques in Turkey, with different types
of cover structures and plan typologies, are designated as study areas. The present study contains two methods which the first one is collecting acoustical data by measurements and the second consists of mathematical modelling software program. The purpose of study to investigate effects of
different plan typology and ceiling structures on acoustical characteristics in mosques with similar volume. Also, distribution of acoustical parameters and the suitability of the values obtained through acoustic simulations and measurements to the recommended values are aimed to be investigated.
As a result of the investigations, it was concluded that the objective acoustic parameters of mosques changed according to the geometric parameter properties.
Field study for the evaluation of the acoustic quality of open-plan offices
Authors: Chevret Patrick , Bonzom Thomas , Lenne Lucas , Brocolini Laurent , Marchand Julien
Published: September 2021

Even if the global health crisis is currently changing the work organisation in offices in the service industry, the problem of noise in open plan offices remains a major challenge with regard to occupational health and well-being. Since 2012, the French National Research and Safety
Institute for the Prevention of Occupational Accidents and Diseases (INRS) has been carrying out acoustic surveys in French open-plan offices by measuring both some usual indicators of empty offices (Tr, D2S, Lp4m, rc, Lp) and also the ambient noise levels in activity. In addition, GABO questionnaires
have been proposed to employees to assess their perception of the noise environment. So far, 50 open spaces were evaluated, with more or less data collected depending on the situation encountered. Approximately 1,400 employees have already answered the questionnaire. All of the sites visited
cover the entire set of activities described by the ISO 22955 standard. An analysis of the links between the acoustic parameters and the perception of employees was carried out. This analysis provides additional information to the studies on the choice of acoustic descriptors and on the use
of sound masking systems that aim to control background noise to reduce noise disturbance due to intelligible conversations.
Exposure to industrial noise: impacts on cognitive performance
Authors: Mesa Casa Pereira Luiz Henrique , Knöfel Björn , Troge Jan , Drossel Welf-Guntram , Klein Marcel , Hübelt Jörn
Published: September 2021

Research on the relation between exposure to noise and cognitive performance inside industrial environments is not as broad as on office environments. For a better understanding of the specific industrial noise problems, participants performed arithmetic tests inside a hemi anechoic
room while they were exposed to sounds of five typical industrial noise sources. The subjects also classified how annoying they perceived the noise signals. The effect of noise on the arithmetic test's performance was larger on accuracy than on velocity, which was verified using a Student
t-test. Spectral-temporal characteristics - especially high frequency content and strong low frequency modulation - appear to relate better with lower performance on the test than high sound levels. Subjects that evaluated noise as more annoying performed worse in a final arithmetic test (under
silence) after being exposed to the noises, indicating a possible cumulative effect of noise on performance. The findings provide a better insight in the cognitive behavior of people who are exposed to industrial noise. Hence, the study will proceed with the specific noise analysis of single
industrial workplaces.
Precision of inertial measurement unit sensors in head-tracking systems used for binaural synthesis
Authors: Jambrosic Kristian , Planinec Vedran , Horvat Marko , Francek Peter
Published: September 2021

Binaural synthesis is the most used sound system for diverse virtual and augmented reality systems nowadays, given its simplicity of implementation and the need of using only two audio channels. It is widely used in computer games, auralization and even audio production. To achieve
the most natural sound field recreation, systems used for binaural synthesis must include a head-tracking sensor to dynamically calculate the binaural signal for the head orientation at any given moment. This is done by inertial measurement unit (IMU) sensors, specifically the triaxial accelerometers,
gyroscopes, and magnetometers. Simpler systems, e.g., Arduino or other embedded systems, provide only raw sensor data, and the orientation is calculated by a processing unit. Other, more complex systems such as smartphones or VR headsets already calculate their position from the raw data using
complex sensor integration algorithms. In this paper, a measurement procedure for measuring the precision of IMU sensors is presented. The need of absolute orientation calibration is addressed, and challenges of sensor data drift are discussed. Measurement results for simple embedded systems
and complex systems found in smartphones are presented, and an estimation of IMU sensor quality for binaural synthesis is made.
Additional noise reduction with diffracting elements on barriers: experimental testing
Authors: Schwanen Wout , Mertens Mark , Wijnant Ysbrand , Vliet Willem Jan van
Published: September 2021

The noise reduction of a (low) noise barrier can be enhanced by using an additional element with quarter-wavelength resonators with varying depths. The so-called WHISwall or WHIStop deflects sound upwards for specific frequencies creating an additional sound reduction. Different experiments
on the WHISwall and WHIStop are performed as input for model validation. The development and validation of the model are described in a separate paper. In this paper the measurement campaign and its results are presented. We performed measurements on two setups. The first setup consists of
a 1.1 meter high WHISwall, a 1.1m high noise barrier and a reference section (without noise measure). Measurements have been conducted with both an artificial sound source and pass by measurements with light and heavy motor vehicles. In a second test setup, the WHIStop was placed on top of
a 4 meter high noise barrier and the diffraction was determined according the European standard EN 1793-4.
Status - International Space Station (ISS) Crewmembers' Noise Exposures
Authors: Limardo Jose , Allen Christopher S. , Danielson Richard W. , Boone Andrew J.
Published: September 2021

Environmental noise in space vehicles, caused by onboard equipment and crew activities, has generated concerns for crew health and safety since early U.S. space missions. The International Space Station (ISS) provides a unique environment where acoustic conditions can be monitored while
crewmembers from the U.S. and their international partners work and live for as long as 6 to 12 consecutive months. This review of acoustic dosimetry data collected to date reveals that the noise exposure limits of NASA's stringent noise constraint flight rule have been exceeded in 41% of
these dosimetry measurements since ISS Increment 17 (2008), with undefined impacts to crew. These measurements do not take into account the effects of hearing protection devices worn by the crew. The purpose of this paper is to provide an update on ISS noise exposure monitoring approaches
and hearing conservation strategies that include acoustic dosimetry data collected since the ISS Increment 55 mission (April 2018). Future directions and recommendations for the ISS noise exposure monitoring program will also be presented, including research initiatives aimed at better defining
the impact of ISS noise on crew health and performance.
Examination of spectral content, peak frequency relationships, and annoyance for unmanned aerial vehicle operations
Authors: Rochat Judy , Singleton Herb , Yoerg Keith
Published: September 2021

Unmanned aerial vehicles (UAVs) can be used for many purposes, servicing delivery, recreational, utility inspection, and film industries, among others. For some applications, use of UAVs can expose communities to a type of noise not currently experienced, with current noise sources
typically related to transportation operations (e.g., aircraft, rail, road noise sources) and home activities (e.g., air conditioning units, lawn care). As such, it is important to understand the type of noise communities will experience with UAV operations. For this paper, a UAV flyover event
and hover event are examined in terms of spectral content and the relationship of peak frequencies. In addition, the peak frequencies and relationships are discussed in terms of those typically associated with annoyance.
A hybrid method for broadband vibroacoustic simulations
Authors: Miller Jared , Sommerfeldt Scott D. , Blotter Jonathan D. , Copley David C.
Published: September 2021

Many methods for simulating acoustic responses of vibrating systems are only suitable for limited frequency ranges, providing either an accurate low frequency or high frequency response. A hybrid method is presented to combine a low frequency modal response and a high frequency statistical
energy response to obtain a unified broadband response. The method is designed to produce an auralizable response. An experimental setup is used to validate the method. Listening tests are conducted to assess the realism of the auralizations compared to measurements. The listening tests confirm
that the method is able to produce realistic auralizations, subject to a few limitations.
An objective evaluation method and experiment on the impact of road traffic noise on the soundscape: The case of West Lake
Authors: Zhang Jiping
Published: September 2021

A positively judged soundscape generally includes both natural and social/cultural sounds in the sonic environment. Road traffic noise (RTN) is a major source of sound that may impact the both, such as the case of West Lake. Many studies examine soundscapes contexts with RTN based on
physical descriptors, and subjective social scientific assessments by their descriptors mainly using onsite questionnaires to develop an understanding of the situation. By application of an objective evaluation method borrowed from speech intelligibility measurement techniques defined as the
signal-to-noise-ratio-loss in the presence of RTN, research of the correlation between background RTN and environmental soundscape is developed by a self contained and evident proof derivation, proposed an objective evaluation method for protecting the soundscape from RTN, and presented the
design and performance of an experiment to verify the method at two roads where RTN is propagated a distance into two roadside urban parks at West Lake. Our goal is the assessment and protection of the environmental soundscape from RTN using a convenient objective evaluation method that supplements
cumbersome subjective investigations, provides an early warning concerning the RTN impact to the soundscape, and a tool how to improve the soundscape within the RTN impacted areas.
Perception of noise from small quadcopter UAVs
Authors: Hui Justine , Kingan Michael , Hioka Yusuke , Schmid, Gian , Dodd George , Dirks Kim , Edlin Shaun , Mascarenhas Sean , Shim Young-min
Published: September 2021

This paper presents the results of a study evaluating the human perception of the noise produced by small quadcopter UAVs. The study utilised recordings of the noise produced by several different quadcopter UAVs in hover and in constant-speed flight at a fixed altitude. These recordings
were made using an eigenmic system. The recordings were reproduced using a 3D sound reproduction system located in the large anechoic chamber at the University of Auckland. Human subjects were asked to rate the annoyance of the recordings. The responses of the test subjects are presented and
these are compared with objective metrics to assess suitable metrics for quantifying the impact of noise from these vehicles on humans.
Measurement of sound absorption coefficient in a reverberant room using probability density function of damping constant
Authors: Goto Kosuke , Nakagawa Takehiko , Yamada Yoshinari
Published: September 2021

The measurement method of the sound absorption coefficient in a reverberation room is standardized in ISO 354. However, the measurement accuracy often deteriorates at low frequencies. This paper proposes a method that improves the measurement accuracy of the sound absorption coefficient
at low frequencies. It calculates the sound absorption coefficient using reverberation time (RT) that is derived from the distribution of a damping constant for a sinusoidal input. The measured values by the proposed method were compared with those by the ISO 354 method. As a result, the proposed
method reduces the spatial variability of RT and gives a better agreement with the statistical absorption coefficient that is calculated by a transfer matrix model at low frequencies.
Energy fluctuations in recorder pipes during transient sound attacks and steady state sound
Authors: Onitsuka Hirofumi , Shoji Tetsuro , Uchida Katsuya , Miki Akira
Published: September 2021

The evaluation of temporal and spatial fluctuations of energy using compressible fluid analysis is proposed as an effective method to clarify the fundamental mechanism of the self-sustained oscilla-tions in a actual recorder. The main factors of the self-sustained oscillations are investigated
in more detail by evaluating not only the steady state of the sound where the flow field and the sound field are completely coupled, but also the characteristics at the attack transient of the sound before the coupling is established. By analyzing the large energy fluctuations that occur just
below the edge of the labium in the attack transient, it was shown that this phenomenon may be one of the main causes of the self-sustained oscillations. And the characteristics of the energy fluctuations and sound power generation during the steady state of the sound are discussed. It was
also focused on the energy variations in another region that is near the exit of the windway.
An innovative X-shaped vibration isolation mount with tunable quasi-zero-stiffness property
Authors: Bian Jing , Jing Xingjian , Tian Yishen
Published: September 2021

Passive vibration isolation is always preferable in many engineering practices. To this aim, an innovative, compact, and passive vibration isolation mount is studied in this paper. The novel mount is adjustable to different payloads due to a special oblique and tunable stiffness mechanism,
and of high vibration isolation performance with a wider quasi-zero-stiffness range due to the deliberate employment of negative stiffness of the X-shaped structure. The X-shaped structure has been well studied recently due to its excellent nonlinear stiffness and damping properties. In this
study, by using of the negative stiffness property within the X-shaped structure, the X-shaped mount (X-mount) can have an obviously larger vibration displacement range which maintains the quasi-zero-stiffness property. A special oblique spring is thus introduced such that the overall equivalent
stiffness can be much easily adjusted. Systematic parametric study is conducted to reveal the critical design parameters and their relationship with vibration isolation performance. A prototype and experimental validations are implemented to validate the theoretical results. It is believed
that the X-mount would provide an innovative technical upgrade to many existing vibration isolation mounts in various engineering practices and it could also be the first prototyped mount which can offer adjustable quasi-zero stiffness conveniently.
Further investigation on pockets of quiet within historical city centres: the case of widenings
Authors: Masullo Massimiliano , Toma Roxana Adina , Maffei Luigi
Published: September 2021

Making available quiet zones for the urban population is a key factor to offer them the possibility to have restorative experiences and relief from stressful city life. Although these zones are often associated with vast green parks, the latter are usually located outside or far from
cities' centres. Moreover, if we consider the case of historical city centres, they are almost absent. In previous research, we have focused on searching for alternative quiet spaces that inhabitants and tourists could use as a temporary refuge from urban noise and chaos. In these studies,
we have shown that thanks to their acoustics peculiarities and several other non-acoustic characteristics, the cloisters and the courts of historic buildings have a high potential to induce restoration. Nevertheless, among the narrow streets of the historic cities centres, the widenings can
also provide a small contribution to a temporary restoration of people. This paper investigates the restorative potentiality of these further spaces and compares the outcomes carried out from binaural recordings and in situ interviews with those of cloisters and courts of historic buildings
within the ancient city centre of Naples.
Implementing auralized CPB sounds on a pedestrian simulator
Authors: Soares Francisco , Pereira Frederico , Silva Emanuel , Silva Carlos , Sousa Emanuel , Freitas Elisabete
Published: September 2021

Recently, several studies on pedestrian safety and particularly those addressing pedestrian crossing behaviour and decision-making, have been performed using virtual reality systems. The use of simulators to assess pedestrian behaviour is conditioned by the feeling of presence and immersion,
for which the sound is a determining factor. This paper presents an implementation procedure in which tyre-road noise samples are auralized and presented as auditory stimuli in a virtual environment, for assessing pedestrian crossing decision-making. The auditory samples obtained through the
Close Proximity (CPX) method and subsequently auralized to represent Controlled Pass-By (CPB) sounds reproduce the sounds of a vehicle approaching a crosswalk. The auralized sounds together with the presentation of visual stimuli composed an experiment which was carried out with 30 participants.
Safety indicators, as the time-to-passage at the moment that participants decided to cross a virtual crosswalk and the minimum time-to-collision were registered and compared with data obtained in real-world road crossings. A comparison with real world data points to a close alignment between
results obtained in virtual and real environments, indicating a good suitability of the approach for studying pedestrian crossing behaviour.