bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact sound prediction of finite floor structures with the modal transfer matrix method
Authors: Vastiau Jasper , Van hoorickx Cédric , Reynders Edwin
Published: September 2021

The transfer matrix method (TMM) is commonly employed for wave propagation analysis in layered media of fluid, elastic and porous nature. Up to now it has been used extensively to analyze airborne sound transmission and sound absorption. Its use for impact sound transmission has been
investigated to a limited extent, i.e. for thick homogeneous elastic plates of infinite extent and for specific receiver points. This contribution aims to broaden the scope such that the global impact sound, radiated by finite floor structures containing elastic, fluid and/or porous layers,
can be analyzed in a more robust way than previously available in literature. A disadvantage of the conventional TMM is that only floors of infinite extent can be implemented. It is possible to remove this drawback using a spatial windowing technique. Furthermore, the modal behavior of the
floor is approximately taken into account by projecting the impact force onto the mode shapes and only allowing for the propagation of those waves, corresponding to modal wavenumbers, in the structure. Predictions of the radiated sound power are made for various bare floors and floating floor
systems of both infinite and finite extent.
Measuring the force due to standard tapping machine and floor impedance for ASTM standards
Authors: Girdhar Sunit , Barnard Andrew R. , LoVerde John , Dong Wayland
Published: September 2021

The standard tapping machine used for the ASTM test standards on impact noise insulation does not have any provision to measure input force. A modified tapping machine with a force transducer was used for eight different residential floors, revealing that the force injected into the structure varies by approximately 37 dB. This variation is due to the combination of the tapping machine and the floor compliance. On one of the floors for the same test, the force injected due to the tapping machine varies by 2.6 dB for a single hammer. The floor impedance was also measured using accelerometers and the lightweight floor impedance is about 40 dB lower than heavyweight floors. The impedance varies by 20 - 30 dB throughout the frequency spectra for the four light-weight joist-framed floors. The authors propose that this injected force be measured, and an injected-to-radiated energy ratio be used to compare various floor-ceiling assemblies.
Computationally efficient source grid selection and source interpolation in computational aeroacoustics applied to an axial fan.
Authors: Wurzinger Andreas , Kaltenbacher Manfred , Schoder Stefan
Published: September 2021

The noise generation of an axial fan is mainly caused by flow-induced noise and can therefore be extracted from its aeroacoustics. To do so, a hybrid approach separating flow and acoustics is well suited due to its low Mach number. Such a computationally efficient hybrid workflow requires
a robust conservative mesh-to-mesh transformation of the acoustic sources as well as a suitable mesh refinement to guarantee good convergence behavior. This contribution focuses on the mesh-to-mesh transformation, comparing two interpolation algorithms of different complexity towards the applicability
to the aeroacoustic computation of an axial fan. The basic cell-centroid approach is generally suited for fine computational acoustic (CA) meshes and low phase shift, while the more complex cut-volume method generally yields better results for coarse acoustic meshes. While the cell-centroid
interpolation scheme produces source artifacts inside the propagation domain, a grid study using the grid convergence index shows monotonic convergence behavior for both interpolation methods. By selection of a proper size for the source grid and source interpolation algorithm, the computational
effort of the experimentally validated simulation model could be reduced by a factor 4.06.
Evaluation method of military aircraft noise using AI analysis of aircraft images
Authors: Fujita Etsushi , Higashioka Taichi , Sugiura Manabu , Kohashi Osamu
Published: September 2021

In recent aircraft noise survey in Japan, noise data is associated with each aircraft by flight log or by radio information including transponder signals. Especially, above Tokyo metropolitan area, flight tracks are tangled extremely each other, therefore assessments from various perspectives
such as departure / arrival airport, used runway, aircraft model, and operator have been demanded for determining noise policies. However, for military aircrafts, it is not easy to identify their information with the same way as commercial aircrafts, because their flight logs are not disclosed
and many of them do not emit transponder signals like commercial aircrafts. Therefore, manned 24 hours survey around air bases have been necessary to obtain flight information of military aircrafts. In this paper, we propose an AI-based analysis using captured aircraft images for obtaining
actual flight data of military aircrafts. In the past trials, we could determine the takeoff/landing time and the aircraft model by the above method. Associating these information and noise data measured at monitoring stations, details of noise characteristics around the air base can be clearly
grasped. Advanced analysis of the causes of noise impact will lead effective and concrete countermeasures.
Method for localisation of sound sources and aggregation to an acoustic centre
Authors: Weber Yannik , Behrendt Matthias , Gohlke Tobias , Albers Albert
Published: September 2021

Preliminary work by the IPEK - Institute of Product Engineering at KIT has shown that the simulated pass-by measurement for exterior noise homologation of vehicles has relevant optimization potential: the measurement can be carried out in smaller halls and with a smaller measurement
setup than required by the norm and thus with less construction cost and effort. A prerequisite for this however is the scaling of the entire setup. For the scaling in turn, the sound sources of the vehicle must be combined to a single point sound source - the acoustic centre. Previous approaches
for conventional drives assume a static centre in the front part of the vehicle. For complex drive topologies, e.g. hybrid drives, and unsteady driving conditions, however, this assumption is not valid anymore. Therefore, with the help of an acoustic camera, a method for localizing the dominant
sound sources of the vehicle and a software-based application for summarizing them to an acoustic centre were developed. The method is able to take into account stationary, unsteady and sudden events in the calculation of the acoustic centre, which is moved as a result. Using substitute sound
sources and two vehicles, the method and the used measurement technology were examined and verified for their applicability.
Traveling-wave control of the bending wave in a beam for high quality sound radiation
Authors: Lee Ki-Ho , Ih Jeong-Guon , Jung Donghyun
Published: September 2021

The bending wave generated by the actuator exciting a panel can be controlled to be in the traveling wave form void the structural resonances, which deteriorates the radiated sound if the panel is used as a speaker. Although such traveling-wave control method (TCM) yields a wider effective
frequency range than the modal control method, the requirement of using many actuators is the practical problem yet. If a beam is employed instead of a plate as a panel speaker, the number of actuators can be reduced despite a smaller radiating surface than a plate. This study adopts three
actuators for the beam control using TCM. An actuator excites the beam in the middle position, and the two actuators near the two edges are used to suppress the reflected waves from the boundaries. The control result shows that the driving-point mobility of the primary actuator is converted
into that of an infinite beam, which means that the boundaries are changed into anechoic ones and the structural resonances are eliminated. Accordingly, the beam radiates a smooth sound spectrum without sharp peaks and troughs related to the resonant responses. Effects of material and dimension
in determining the effective frequency range are also explored.
Statistical assessment of A-weighted sound power level for printer with electrophotographic engine
Authors: Shimoda Kohei
Published: September 2021

Statistical distribution and statistical upper limit (the value which 93.5 % of the batch of new equipment are expected to lie) of A-weighted sound power level for one office printer were experimentally estimated from 10 new samples picked up from market. The printer is capable of A4-size
printing with electrophotographic engine which corresponds Annex C.16 Page printers in ECMA74 17th (2019). A-weighted sound power level for continuous printing mode was determined in accordance with noise test code for ITTE (Information Technology and Telecommunications Equipment such as printers
and personal computers), ISO 7779:2018 and ECMA-74 Annex C. Sample standard distribution of production of overall A-weighted sound power level (determined from 100-10000 Hz one-third-octave band) is 0.25 dB, whereas individual one-third-octave band has larger distribution. The value obtained
is better than reference distribution 1.32 dB set in ISO 9296:2017 which states estimation of statistical upper limit value of the batch of equipment for ITTE.
Upper hemisphere sound image control with horizontal-arranged loudspeakers based on parametric head-related transfer functions
Authors: Miura Syumpei , Iwai Kenta , Soeta Yoshiharu , Nishiura Takanobu
Published: September 2021

The 22.2 multichannel sound system has been developed for an ultra high-definition television system. This system consists of twenty two loudspeakers and two sub-woofers called low frequency effects, and can reproduce three-dimensional sound image appropriate to the ultra high-definition
television system. However, this system has a problem of high cost to install. On the other hand, the multichannel sound system with horizontal-arranged loudspeakers has lower cost to install than full scale one. However, this system cannot reproduce an upper sound image. Therefore, in this
paper, we propose the upper sound image control with horizontal-arranged loudspeakers based on the parametric head-related transfer functions. The proposed method generates binaural signals to control the sound image elevationally based on the parametric head-related transfer functions in
the median plane. Also, the proposed system uses the interaural level difference to control the sound image of binaural signals azimuthally. Finally, the proposed method generates output signals for horizontal-arranged loudspeakers from binaural signals by designing a multichannel inverse
system based on multi-input / output inverse theorem. The experimental results show that the proposed method can control the sound image to elevation angle with the same accuracy as binaural lreproduction. The 22.2 multichannel sound system has been developed for an ultra high-definition television
system. This system consists of twenty loudspeakers and two sub-woofers called low frequency effects, and can reproduce three-dimensional sound image appropriate to the ultra high-definition television system. However, this system has a problem of high cost to install. On the other hand, the
multichannel sound system with horizontal-arranged loudspeakers has lower cost to install than full scale one. However, this system cannot reproduce an upper sound image. Therefore, in this paper, we propose the upper sound image control with horizontal-arranged loudspeakers based on the parametric
head-related transfer functions. The proposed method generates binaural signals to control the sound image elevationally based on the parametric head-related transfer functions in the median plane. Also, the proposed system uses the interaural level difference to control the sound image of
binaural signals azimuthally. Finally, the proposed method generates output signals for horizontal-arranged loudspeakers from binaural signals by designing a multichannel inverse system based on multi-input / output inverse theorem. The experimental results show that the proposed method can
control the sound image to elevation angle with the same accuracy as binaural reproduction.
Speech extraction with RGB-intensity gradient on rolling-shutter video
Authors: Yoshizawa Tsubasa , Yoshida Atsushi , Iwai Kenta , Nishiura Takanobu
Published: September 2021

Recent studies have been proposed to extract speech from the captured video of objects vibrating by sound waves. Among them, from the viewpoint of equipment cost, the method of extracting speech from the video captured by rolling-shutter cameras, which are widely used in consumer digital
single-lens reflex cameras, has been attracting attention. The conventional method with the rolling-shutter video uses a grayscale video for processing based on phase images. However, a grayscale video has a smaller dynamic range than an RGB video, and thus the speech extraction accuracy of
the conventional method degrades. Therefore, this paper proposes a speech extraction method based on RGB-intensity gradients on an RGB video to improve speech extraction accuracy. The proposed method extracts the speech by calculating the similarity of R, G, and B intensity gradients, and
using these three intensity gradients expands the dynamic range. The experimental results on the quality and intelligibility of the extracted speech show our proposed method outperforms the conventional method.
Noise assessment of taxibotted versus conventional taxiing operations using a phased microphone array
Authors: von den Hoff Bieke , Snellen Mirjam , Simons Dick G.
Published: September 2021

In sustainable aviation the focus is mostly applied to the greenhouse gas emissions during flight. However airports have an increasing interest in reducing emissions during ground operations such as taxiing for example to improve the local air quality. Amsterdam Airport Schiphol started
a pilot for sustainable taxiing with a pilot-controlled hybrid-electric aircraft towing vehicle called TaxiBot in 2020. The COVID-19 pandemic created an opportunity for extensive operational testing on a near-empty airport. Due to the low background noise levels in this situation, also a noise
assessment of taxiing with the TaxiBot versus conventional two-engine taxiing was performed. This assessment can be used to evaluate the noise levels to which ground workers or neighbouring communities are exposed due to TaxiBot operations. For the noise measurements a phased microphone array
was used, which allowed not only for a noise level and directionality assessment, but also for noise source identification. This paper compares the noise emissions and noise sources between a taxibotted and conventional taxiing operation. The results show that a taxibotted taxiing operation
produces significantly lower noise levels. Additionally, acoustic imaging shows that the TaxiBot engine is the main noise source for a taxibotted pass-by manoeuvre.
Psycho-physiological evaluations of low-level impulsive sounds produced by air conditioners
Authors: Soeta Yoshiharu , Onogawa Ei
Published: September 2021

Air conditioners are widely used in buildings to maintain thermal comfort for long time. Air conditioners produce sounds during operation, and air conditioners are regarded as one of the main noise sources in buildings. Most sounds produced by the air conditioner do not fluctuate over
time and sound quality of the steady sounds produced by the air conditioner have been evaluated. However, air conditioners sometimes produce low-level and impulsive sounds. Customers criticizes such sounds are annoying when they sleep and they spend time quietly in the living room. The aim
of this study was to determine the factors that significantly influence the psycho-physiological response to the low-level impulsive sounds produced by air conditioners. We assessed the A-weighted equivalent continuous sound pressure level (LAeq) and factors extracted from the autocorrelation
function (ACF). Subjective loudness, sharpness, annoyance, and electroencephalography (EEG) were evaluated. Multiple regression analyses were performed using a linear combination of LAeq, the ACF factors, and their standard deviations. The results indicated that LAeq, the delay time of the
first maximum peak, the width of the first decay of the ACF, and the magnitude and width of the IACF could predict psycho-physiological responses to air conditioner sounds.
Effect of fiber cross-section on the transport and acoustic properties of fibrous materials
Authors: Yang Sung Soo , Kang Yeon June
Published: September 2021

Fibrous materials can efficiently dissipate acoustic energy, and their intrinsic properties are determined by fiber geometries (microscale). In this study, the effect of cross-sections of fibers on the transport and acoustic properties of fibrous materials was investigated. First, fibers
of various cross-sections were modeled by adjusting their open porosity. The representative elementary volumes of fiber structures were generated to describe the periodic unit-cell structures. Next, the transport properties (such as static airflow resistivity, high-frequency limit of the dynamic
tortuosity, viscous characteristic length, thermal characteristic length, and static thermal permeability) of fibrous materials were calculated by solving numerical problems using the finite element method. These properties of fibrous materials with complex cross-sections were compared with
those with circular cross-sections. Finally, the sound absorption coefficients were predicted using the Johnson-Champoux-Allard-Lafarge (JCAL) model and rigid frame approximation, and the differences in sound-absorbing behavior were analyzed. This study can provide insights into the design
of lightweight fibrous materials while maintaining optimal sound absorption performance.
Low frequency vibration suppression of a moderate thick cabin structure by multiple piezoelectric patches shunted with RL-double negative capacitance circuits
Authors: Zheng Zhiwei , Li Feng , Huang Xiuchang , Su Zhiwei , Hua Hongxing
Published: September 2021

Multiple piezoelectric patches shunted with RL-double negative capacitances circuits, which are bonded on the bulkhead, are proposed to control the resonant response of multiple low frequency modes of a moderate thick cabin structure. Dynamic modeling of the electromechanical coupling
system of the cabin structure and the piezoelectric shunt circuit is established by employing the three-dimensional finite element. Optimum tuning strategy is based on the trial and error method. It is shown that the proposed approach is effective in enhancing the generalized electromechanical
coupling coefficient and controlling the low frequency modes that exhibits coupled deformation of the bulkhead and cabin structure.
Biophilic Sound Masking Systems: Promoting Acoustical Comfort in Workspaces
Authors: Salter Ethan , Mills Dylan
Published: September 2021

Promoting speech privacy and acoustical comfort in office buildings has always been an important consideration for designers, owners, and occupants. Acoustical comfort has many degrees, including reduction of stress, enhancing focus, and reducing distractions. It can also create a more
pleasurable and relaxing environment. Concurrently, the sustainable and green design movements have evolved the "language" of design and building to include a more holistic understanding of occupant comfort. This includes the materials and systems that occupants interface with and
use. Additionally, interior environmental quality considerations, including noise, are incorporated into green building rating systems such as WELL, LEED, CHPS, and others. However, it is not merely about providing a slightly better or more efficient system, but also understanding on a deeper
level the effects of a building's environment on people's health. One aspect of this is the concept of "biophilia," where designers look to natural systems and materials for inspiration. The interior acoustical environment is a significant part of that. Electronic sound masking systems
have been used in office environments for decades, and their efficacy, when appropriately designed and installed, has been proven repeatedly. What has been changing in recent years is the concept of biophilic sound masking systems, which do not merely broadcast broadband noise (AKA pink noise
or "white" noise) in a space. These systems can broadcast "natural" sounds such as running water, animals, wind, etc. that are not only pleasing and soothing, but also effective in sound masking. This paper will describe biophilia in general how it relates to the interior
noise environment, and related design considerations. In addition, the paper includes a case study of an office building project that employed a sound masking system with biophilic capabilities.
Automate TNM Input Process Using Python
Authors: Ying Ronald , Patel Nish
Published: September 2021

Since 2004, we have been using TNM 2.5 to analyze the noise impacts from traffic. The decades-old Graphical User Interface (GUI) is inadequate to handle large scale projects with hundreds of receptors and roadways. TNM 3.0 has a vastly better user interface, but its import function
is still buggy as of early 2021. Therefore, we have developed an interim solution to automate massive input using ESRI ArcGIS software and Python's third-party packages such as Pandas, PyAutoGUI, and subprocess. This process is used to automate building barrier input and roadway/traffic inputs
in the old TNM 2.5 user interface.
'Attack of the Drones' Exploration of Sound Power Levels Emitted and the Impact Drone's could have upon Rural Areas, Roxwell, Essex, UK
Authors: Nixon Josephine , Dance Stephen
Published: September 2021

This study considers the acoustic emission from a DJi Phantom 4 commercial drone using different rotor blades. Measurements were taken from a hovering drone with four commercial product blade configurations. Measurements were taken in accordance with (BS) EN ISO 3745: 2009 'Acoustics
- Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms'. The aim of the project was to consider the sound characteristics emitted, specifically tonality and to determine the distance
a drone could be heard from, with the different blade configurations, in a rural setting. By considering the different blade configurations within a rural setting, the role drones have within society is considered.
A study on the development and application of program for planetary gear design considering planetary gear noise and efficiency
Authors: Lee Hyun Ku , Kim Moo Suk , Hong Sa Man , Yoo Dong Kyu , Kahraman Ahmet , Harianto Jonny
Published: September 2021

In general, gear mechanical loss is associated with the friction of the lubricating contact surface of the gear and bearing that transmit the power, and a no-load spin loss which is load independent occurs due to gear rotation and the interaction of the bearing component with the lubricating
element. In order to minimize planetary gear loss, it is desirable to design by checking the efficiency at the concept design stage. However, a design technique that considers the noise and efficiency of a planetary gear set simultaneously has not been achieved so far. In this paper, a program
called 'pRMC with EHL' to check together the efficiency and noise that affected by gear specifications has been developed. By using developed program, planetary gear sets specifications have been designed. And through the experimental evaluation, automatic transmission efficiency could be
reduced by 0.3% in combination fuel consumption mode and the planetary gear vibration could be also reduced by 10 dB than former design. Through this designing verification and input parameter correlation, a new planetary gear set designing process has been come up with successfully at the
concept design stage.
Modeling Industrial Pipe Insulation Performance
Authors: Herreman Kevin
Published: September 2021

Reducing industrial noise emission utilizing jacketed pipe insulation is critical to reducing noise in industrial spaces. The ISO 15665 standard defines a testing process for measurement of the acoustical performance of installed and jacketed pipe insulation systems. However, the cost
of testing per this standard, especially when using an external laboratory, can be very costly. That makes the development of a model to accurately estimate the performance of single, and multilayered, jacketed pipe insulation highly desirable. Utilizing a one-dimensional theoretical acoustic
model along with empirical data, a model with sufficient accuracy to provide insertion loss results relative to the ISO 15665 standard was created. The creation and resulting functionality of the model for determining jacketed pipe insulation insertion loss and comparison of the resulting
data to test results will be discussed herein.
Modeling Large Diameter Industrial Pipe Insulation Performance
Authors: Herreman Kevin
Published: September 2021

As previously presented, reducing industrial noise emission utilizing jacketed pipe insulation is critical to reducing noise in industrial spaces. The ISO 15665 standard defines a testing process for measurement of the acoustical performance of installed and jacketed pipe insulation
systems. To provide a cost-effective method for evaluating various types of multilayered jacketed pipe insulation a model was developed. The model accurately estimates the performance of single, and multilayered, jacketed pipe insulation. Validating the use of the model to very large pipe
diameters is highly desirable as the cost to test is significantly higher than testing the medium or small diameter pipe insulation. The estimated insertion loss result from the model is compared to validation testing results for large diameter jacketed pipe insulation are reported herein.
Digitalizing sound in your personal space
Authors: Kappagantu Ramana , Karlson Karl , Vansant Koen
Published: September 2021

Design specifications for appliances are usually in the context of standard acoustic rooms like anechoic (full or hemi) and sometimes reverberant. However in the world of infotainment industry the devices are operated in your personal space - a generic environment like that of a living
room and they continuously interact with other devices in real time. One has to take into account the scattering and absorption of sound from different surfaces and how they constructively and destructively interfere in generating a signature sound for the room and the devices. This environmental
impact increases the design space significantly and makes it impractical to consider physical prototyping and testing. Simulating the acoustic behavior of the devices in a room environment has been attempted in the past and were successful only for lower frequency ranges or for smaller rooms.
High end Multipole BEM and FEM Adaptive Order technologies have emerged in the recent past and together with parallel cloud computing make the modeling of generic room environment more feasible, up to a few kHz given adept hardware setup. A different, more asymptotic method like Ray Tracing
provides a real breakthrough here and enables taking on the full audible frequency range and large rooms, in at least one order of magnitude faster solving times compared to the more conventional FEM and BEM method, which further supports optimization possibilities for different configurations
in reasonable time.
Studying acoustical capacity and quality of verbal communication in occupied restaurants
Authors: Paine Jared , Wang Lily M.
Published: September 2021

Sound level data and occupancy data has been logged in five restaurants by the research team at the University of Nebraska - Lincoln. Sound levels and Occupancy at 10 second intervals were documented over time periods of two to four hours during active business hours. Noise levels were
logged with dosimeters distributed throughout each restaurant, and occupancy was obtained from images recorded by infrared cameras. Previous analyses of this data have focused on average sound levels and statistical metrics, such as L10 and L90 values. This presentation focuses on each restaurant's
Acoustical Capacity and Quality of Verbal Communication, as introduced by Rindel (2012). Acoustical Capacity is a metric describing the maximum number of persons for reasonable communication in a space, calculated from the unoccupied reverberation time and the volume of the space. Quality
of Verbal Communication is a metric describing the ease with which persons in the space can communicate at a singular point in time, depending on the reverberation time, the volume of the space, and the number of occupants in the space.
Aeroacustic and aerodynamic investigating of a new airfoil trailing-edge noise-suppressing design
Authors: Salama Yehia , Rocha Joana
Published: September 2021

In this work, a new noise suppressing airfoil trailing-edge design, termed "finned serrations", is presented and numerically evaluated. This brand-new approach consists of the superposition of two different noise suppressing morphological features inspired by the wings of
the owl. Embedded Large Eddy Simulations are employed in tandem with the Ffowcs WilliamsHawkings model to predict and analyze the design aerodynamics and aeroacoustics and compare the obtained output to that of a flat trailing-edge airfoil. Finned serrations are shown to combine the effects
of having finlets and serrations. Because of the bluntness of the serration roots, the airfoil is subject to vortex shedding, while the flow is generally decorrelated in the spanwise direction, thanks to the channeling effect of the finlets. The turbulent kinetic energy distribution close
to the airfoil trailing-edge surface is also significantly altered, as the more energetic eddies are convected away from the airfoil surface. Lastly, mixing across the airfoil surface is improved, and the average size of the turbulent coherent structures near the airfoil trailing-edge is reduced.
The presented results suggest that the coupling of different noise-suppressing mechanisms is a promising path to explore, with the goal of coming up with new, quieter trailing-edge configurations.
Study on acoustic environment of canteens in South China University of Technology
Authors: Zhou Ziyu , Wang Hongwei
Published: September 2021

In order to understand the characteristics of the acoustic environment of University canteens, the canteens of South China University of Technology were selected as the research objects, and the acoustic parameters were measured on the spot and the questionnaire survey was conducted.
The results show that the average sound pressure level of restaurants with smaller area is lower than that of restaurants with larger area, and the sound pressure level of dining space first increases rapidly, then increases slowly, and finally remains unchanged with the increase of the number
of diners. In the aspect of restaurant acoustic environment satisfaction evaluation, the space with the smallest dining area has the highest acoustic environment satisfaction evaluation level, and the collision sound of tableware collection and table and chair moving has the highest correlation
with the acoustic environment satisfaction evaluation. In terms of different types of noise sources, diners think that the most disturbing noise for conversation is the voice of the surrounding people, followed by the collision of tables and chairs and the collection of tableware, and the
least disturbing noise is the noise of air conditioning and kitchen equipment.
Vehicle interior noise and vibration prediction by combination analyses of Component and Operational TPA
Authors: Tanioka Takuma , Yoshida Junji
Published: September 2021

In this study, we propose an analytical method consisting of Operational TPA (OTPA) and Component TPA (CTPA) to predict the vehicle interior noise and vibration without the vehicle operational test in case the noise source such as engine was modified. In the proposed method, the blocked
force of the noise source was obtained at a test bench and the vibration at the source attachment point on the vehicle was calculated by CTPA. After then, the response point signal (interior noise / vibration) is estimated from several reference point signals including the calculated vibration
by OTPA. For the verification of this method, a simple vehicle model which is composed of four tires and a motor was prepared in addition to a test bench. OTPA was firstly applied to the vehicle model to analyze the contribution from tires and a motor to the body vibration (response point).
The blocked force of a modified motor was obtained by CTPA at the test bench and the force was used to predict the response point by OTPA. Finally, the estimated interior vibration was compared with the actual measured response point vibration when the motor was replaced on the vehicle model
and the accuracy was verified.
Exemplification case studies as a focus for the implementation of best practices related to aircraft noise management at airports
Authors: Ohlenforst Barbara , Burtea N.E. , Heyes G. , Jeram S. , Konovalova O. , Zaporozhets O. , Peerlings B. , Aalmoes R.
Published: September 2021

The current study presents the analysis of seven airport exemplification case studies undertaken in the European project "Aviation Noise Impact Management through Novel Approaches - ANIMA". Best practices related to aircraft noise management at airports in individual airport
contexts were implemented and evaluated. Case studies on communication and community engagement in airport noise management were investigated at Heathrow (Great Britain), Ljubljana (Slovenia) and Rotterdam The Hague (The Netherlands) airports. For Zaporizhzhia (Ukraine) and Iasi (Romania)
airports, the implementation of interventions related to land use planning was examined. The interdependencies between noise and emissions were studied for Cluj (Romania) and Catania (Italy) airports. All case studies were performed under the scope of the corresponding national legislation
and guidelines. Individual characteristics of airport operations were taken into account. The case studies were aligned with expectations and priorities of all involved stakeholders, such as representatives of airport operators, local communities, civil aviation authorities and policy makers.
The efficacy of the noise management case studies is assessed in terms of: the capacity to negotiate consensus outcomes, the extent to which noise impact reductions were achieved; and the participants' satisfaction with the process and outcomes. Experience gained from these studies will be
used to distill best practices for future intervention.
Simplified parametric modeling to predict vibration attenuation provided by on-grade slabs
Authors: Lank Steven , Amick Hal
Published: September 2021

When measured vibration amplitudes at the proposed site for a highly sensitive facility exceed the maximum allowable for the sensitive equipment, mitigation measures must be integrated into the design that will reduce the vibration amplitudes to meet the requirements. Past studies have
shown that thick concrete slabs supported on a well-engineered subgrade can effectively reduce ground borne vibrations at certain frequencies. Predicting the vibration performance of a new slab-on-grade can be a significant challenge, however, as the performance is highly dependent upon the
site soil conditions and nature of the vibration sources impacting the location, as well as structural characteristics. Large and detailed three-dimensional finite element analysis models of the site conditions and proposed structure are often used for this type of assessment, however development
of such a model requires significant time and cost to develop accurately. This presentation discusses a proposed an alternative simplified parametric modeling technique using two-dimensional plane strain modeling. This technique can be utilized in combination with real-world data to predict
the relative benefit of various slab thicknesses and design features such as structural breaks. The paper will include multiple comparisons between predicted results using this methodology and field measurement results.
Next generation aircraft noise-mapping
Authors: Tengzelius Ulf , Johansson Anders , Åbom Mats , Bolin Karl
Published: September 2021

At CSA, Centre for Sustainable Aviation at KTH Stockholm, several projects have run during the last 4 years. One outcome from this research is the SAFT-program for prediction of aircraft noise contours (noise-mapping) and time-histories in receiving points on ground. SAFT is a versatile
and comprehensive tool already including several computational methods such as standard ECACdoc.29 method and more accurate time-stepping simulation-based representations of aircraft sound sources (frequency and direction dependent). The program allows for input of "general aircraft trajectory
input" in the sense that either the trajectory data of concern is fitted to the current pre-defined formats or SAFT is easily updated to read a "new" format. Among the pre-defined formats of current version is csv-files prepared from OpenSky Historical database. From these kinds
of data thrust and other noise-predictor variables are extracted and applied for noise-mapping. Moreover, SAFT allows for studies of aggregated air-traffic in defined areas as well as of single event flight-trajectories. And for these almost any metric (L, L, L, L, ...) might be extracted
together with differences in dB, "Delta-dB", between any two scenarios or individual flights. Could be routing, runway-use, individual flight procedures etc. Anticipated future implementations involve drone trajectories and sound-source representations.
A novel corpus developed to evaluate the impact of hospital noise on speech intelligibility
Authors: Perry Sydney , Bent Tessa , Ryherd Erica , Baese-Berk Melissa
Published: September 2021

Hospital noise often exceeds recommended sound levels set by health organizations leading to reductions in speech intelligibility and communication breakdowns between doctors and patients. However, quantifying the impact of hospital noise on intelligibility has been limited by stimuli
employed in prior studies, which did not include medically related terminology. To address this gap, a corpus of medically related sentences was developed. Word frequency, word familiarity, and sentence predictability, factors known to impact intelligibility of speech, were quantified. Nearly
700 words were selected from the Merriam-Webster Medical Dictionary. Word frequency was taken from Lexique, a 51-million-word corpus of American subtitles (Brysbaert & New, 2009). Word familiarity was rated by 41 monolingual listeners. The words were then used to construct 200 sentences.
To determine sentence predictability, the sentences were presented to 48 participants with one word missing; their task was to fill in the missing word. Three 40 item sentence sets with different familiarity / frequency types (low/low, high/low, high/high) were selected, all with low predictability
levels. These sentences and 40 standard speech perception sentences were recorded by two male and two female talkers. This corpus can be used to assess how hospital noise impacts intelligibility across listener populations. Brysbaert, M., & New, B. (2009). Moving beyond Kučera and
Francis: A critical evaluation of current word frequency norms and the introduction of a new and improved word frequency measure for American English. Behavior Research Methods, 41, 977-990. doi:10.3758/BRM.41.4.977.
Open source acoustic model development for natural and protected environments
Authors: Ambaskar Adwait , Sparrow Victor
Published: September 2021

Natural quiet and the sounds of nature are important natural resources and experiencing them is an important aspect of outdoor recreation experiences. Anthropogenic sound can negatively impact these resources and diminish the benefits realized from outdoor recreation. On public lands
where many types of recreation share trails and landscapes, the sounds produced by some types of recreation (e.g., motorized recreation) can negatively impact the experiences of others. To effectively manage public resources including natural soundscapes and recreation opportunities, public
land and recreation managers need an understanding of the effects of recreation-caused sounds like those associated with motorized recreation. Acoustic models for recreation and protected areas provide an essential tool to help in predicting sound levels generated by these anthropogenic sources
and can aid in studying the extent of potential recreation conflicts, while providing a definite direction to mitigate such conflicts. An open source outdoor sound propagation model integrated with Geographic Information Systems (GIS) lays out a good foundation for mapping visitor experience
affected by sound sources like gas compressors and motorized recreation sounds. The results thus produced present a preliminary version of an outdoor sound propagation tool, to assist parks and state forest services in making important management decisions to refine visitor experience.
Multilayer treatment for subwavelength and broad absorption
Authors: Costa Baptista Josué , Roland-Fotsing Edith , Mardjano Jacky , Therriault Daniel , Ross Annie
Published: September 2021

Single layer optimized microchannels (268µm channels size) present high absorption at the quarter-wave resonance frequency (2460Hz for 30mm-thick treatment) but cannot provide significant absorption at lower frequencies. In this work, the absorption coefficient of multilayer treatments
with 2, 5, 10- and 30-layers of channels with size varying from 50µm to 15mm was numerically optimized. The equivalent fluid wave number and characteristic impedance of each layer were predicted using the JCAL model. The Double-scale Asymptotic Method (DAM) was used to obtain the JCAL
parameters. The multilayer treatment absorption was modelled with the Transfer Matrix Method (TMM). It was shown that multilayer treatments present superior absorption than single layer. For instance, bilayer treatment made of a 1mm-thick top layer (facing incident wave) of channels of 58µm
and a 29mm-thick bottom layer of channels with 8.1mm provides perfect absorption around 1200Hz (i.e. 1260Hz below the quarter-wave resonance frequency of 30mm-thick single layer treatment). Alternatively, a 30-layer treatment with channels size varying from 100µm to 9.6mm provides absorption
higher than 0.8 between 1350 and 6270Hz (i.e. 54% higher than single layer treatment with same thickness). These results pave the way to the fabrication of new multilayer treatments with interesting subwavelength and broadband absorption capabilities.
Deep learning-enhanced single point sound source localization for spherical microphone array
Authors: Lee Soo Young , Chang Jiho , Lee Seungchul
Published: September 2021

In this contribution, we present a high-resolution and accurate sound source localization via a deep learning framework. While the spherical microphone arrays can be utilized to produce omnidirectional beams, it is widely known that the conventional spherical harmonics beamforming (SHB)
has a limit in terms of its spatial resolution. To accomplish the sound source localization with high resolution and preciseness, we propose a convolutional neural network (CNN)-based source localization model as a way of a data-driven approach. We first present a novel way to define the source
distribution map that can spatially represent the single point source's position and strength. By utilizing paired dataset with spherical harmonics beamforming maps and our proposed high-resolution maps, we develop a fully convolutional neural network based on the encoder-decoder structure
for establishing the image-to-image transformation model. Both quantitative and qualitative results are demonstrated to evaluate the powerfulness of the proposed data-driven source localization model.
Relationships between prior experience with fan noise and fan noise ratings in laboratory listening tests
Authors: Töpken Stephan , van de Par Steven
Published: September 2021

In the assessment of noise annoyance and sound quality, judgments made in the laboratory can be influenced by the prior experience that a participant had with the specific type of sound under test. In field tests for noise annoyance, prior experience and individual noise sensitivity
are often part of the data collection but they are not always reported for sound quality evaluations in the laboratory. In this paper, data from listening tests dealing with the perception of fan noise was re-analyzed with respect to the individual prior experience participants had with fan
noise in their life. The answers to a short questionnaire showed that the prior experience of the participants with fan sounds was quite different. For the investigated 30 fan sounds, five categories of every-day situations could be identified, in which fan sounds had been most commonly heard
by the participants. The frequency how often fan sounds had been heard and the overall annoyance by fan sounds in daily life differed considerably between the participants. However, the exploration of the present data did not reveal a strong link between the individual prior experience and
the results of the listening tests when averaged across participants with same ratings.
Loudness- and preference-equivalent levels of fan sounds at different absolute levels
Authors: Claaßen Eike , Töpken Stephan , van de Par Steven
Published: September 2021

In daily life, fans are a common and often unwanted noise source. The sound pressure level in dB(A) is often not sufficient to characterize their unpleasantness and level adjustments would be needed to compensate this shortcoming. In this study, listening experiments were conducted
to determine loudness- and preference-equivalent levels of 19 different fan noise stimuli. For this purpose, the level of each stimulus was varied with an adaptive procedure until it was equally loud (loudness task), or equally preferred (preference task) as a common reference noise with a
fixed level of 75 dB(A). This study repeats an earlier similar study, with a lower reference level of 60 dB(A) and using a larger set of stimuli. The present results are in broad agreement with the results of the prior study, supporting the stability of the matching procedure. Apparently,
level adjustments (penalties) derived from such experiments do not change when stimulus levels are increased by 15 dB. Based on the new results, an existing model developed with a 60 dB(A) reference, can be expanded to also predict preferences for sound sources up to 75 dB(A). Further experiments
with a reference level of 45 dB(A) will complement the data to lower levels.
Perception thresholds for whole-body vibrations on an airplane seat
Authors: Krause Louis , Töpken Stephan , van de Par Steven
Published: September 2021

The comfort during a flight on an aircraft is important for passengers. Like many other physical factors, vibrations of the airplane may negatively affect comfort. To understand the impact of vibration on comfort, it is important to know in which way the vibrations transmitted through
the seat affects the perception of whole-body-vibrations. In this study, perception thresholds for vertical sinusoidal whole-body vibrations with frequencies between 20 Hz and 75 Hz were determined on a vibration platform with a typical economy class aircraft seat bench. Acceleration levels
were recorded with accelerometers placed at the right rear seat rail and inside a seat cushion between the seat surface and the participant. The results show a distinct frequency dependency of the detection thresholds when measured at the seat rail. When taking the difference between the two
measurement positions into account and describing the thresholds by the acceleration levels at the seat cushion, the determined perception thresholds are nearly frequency independent up to 50 Hz. This finding is in good agreement with literature data suggesting that the specific experimental
setup does not play a big role in this frequency range. Differences above 50 Hz might be explained by the additional armrests in the present study.