bluuebunny/crossref_metadata_2025 huggingface dataset:
Bringing the tranquillity rating prediction tool (TRAPT) indoors - an extended investigation of the TRAPT relating to indoor maritime-themed environments
Authors: Oatley James , Swale Mark
Published: December 2023

Tranquil environments are considered quiet, peaceful places where people can get away from everyday life. The Warren, Hull, UK established 1983, is a citywide free project for marginalised and vulnerable young people aged 14-25 that helps to encourage and support them to take control
of their lives and futures by engaging them in all the decision-making that has impact upon the strategic and day to day running of project. In 2022 Cirrus Research successfully adapted Bradford Universities Tranquillity Rating Prediction Tool to numerically predict the perception of tranquillity
experienced by young people within The Warrens youth centre. Furthermore, the young people were involved on a journey, discovering their unique meanings of tranquillity. This paper takes inspiration from the unique maritime history and culture of Hull to facilitate the design of indoor environments
using soundscapes within The Warren. The perception of tranquillity is predicted, measured, and analysed to adapt the tool with new maritime-themed indoor parameters. This study was conducted with the aim of equipping young people with the experience to design maritime-themed soundscapes with
the potential to appeal to a wider age demographic in outdoor spaces around the city.
Influence of ballast heterogeneity on railway induced vibrations and identification of heterogeneous properties of a ballast layer
Authors: Dec Patryk , Cottereau Régis
Published: December 2023

In the context of railway induced vibration, the excitation induced by a passing train can be separated into a quasi-static and a dynamic component. The quasi-static component is related to the weight of the train transmitted through the wheels to the track. The dynamic component is
related to the dynamic train-track excitation resulting from the irregularities of the running surfaces or from the variation of the track stiffness. At sub-Rayleigh speed on a track with longitudinally invariant properties, quasi-static excitation has no significant influence on the far-field
vibration. In this paper, a randomly-fluctuating heterogeneous continuum model of the ballast layer is considered. Mechanical properties are represented as 3D random fields. First, the influence of ballast heterogeneity on the vibration field induced by a moving load is studied. The results
show that heterogeneity is responsible for the generation of waves propagating away from the track. Then an identification process of the heterogeneous model of the ballast is presented based on experimental measurements of train passages.
Using Agglomerative Hierarchical Cluster analysis to validate Turkish perceptual attributes emerged by a corpus-driven data
Authors: Yilmazer Semiha , Fasllija Ela , Alimadhi Enkela , Sahin Zekiye , Mercan Elif , Dalirnaghadeh Donya
Published: December 2023

This study aims to provide validated Turkish perceptual attributes and ponders how a pool of affective quality attributes can be obtained and be representative of the language in the Republic of Türkiye. Based on the historical development of Türkiye, the study also presumes
that various lexical words having the same meaning can be achieved when exposed to different socio-cultural contexts. Firstly, to consolidate a corpus, an online questionnaire was prepared and sent to 196 native Turkish bilingual speakers from all around Türkiye. Secondly, twenty-four
binaural sound recordings were collected from seven public spaces to be performed in the listening test. In data analysis, bipolar adjective pairs were found by using Spearman's rank correlation coefficient. The result showed that the highest correlations among the sixty-four pairs are mainly
on the pleasant-unpleasant continuum. Agglomerative hierarchical cluster analysis was used to cluster the collected adjectives. The result indicated four top-level categories. The terms grouped on the first cluster found their dichotomous on the fourth cluster while maintaining the same relationship
in the pleasant-unpleasant continuum.
A guidance on measurement and evaluation methods for underwater sounds focusing on offshore windfarms
Authors: Akamatsu Tomonari , Aida Yoshiaki , Imasato Motonobu , Matsumoto Sayuri , Endo Yasuhiko , Kamoshida Takashi , Kida Yukihiro , Sawa Takao , Deguchi Mitsuyasu , Shimura Takuya , Sakamoto Shingo , Takeoka Shigeaki , Takekoshi Tetsuro , Tsuchiya Takenobu , Mishima Yuka , Miyamoto Yoshinori , Mori Kazuyoshi
Published: December 2023

Carbon neutral is the global agenda in these years. Offshore windfarm is expected to be the major renewable energy sources. During construction and operation, intensive pulse noise and long-term continuous noise are radiated due to pile driving and windmill rotation. In 2021, we proposed
a guidance on measurement and evaluation methods for underwater sounds based on discussion among a study group organized by Marine Acoustics Society of Japan. The guidance focuses on the method of underwater noise measurement and assessment of the effect of noise on aquatic animals. Long-term
recording using a fixed recorder is recommended to identify the background noise level and its seasonal changes in the potential construction site. Measurement of received sound levels to three directions from the pile up to 6 km is recommended to know the asymmetric noise field due to complicated
shallow water propagation. The distance at the background noise level masks radiated sound is defined as "safe distance". Noise impact assessment should be conducted in the area within this distance. This guidance is not completed yet. It should be revised according to the field
tests. In addition, noise exposure criteria for each species in the ocean is required.
Approaches to address response variations in psychoacoustic tests focused on the assessment of tonal office noise
Authors: Song Guochenhao , Davies Patricia , Liu Yangfan
Published: December 2023

Tonal noise from information technology and service equipment is known to be a problem. A proper understanding of the annoyance due to tonal noise is valuable for guiding the design of a comfortable office environment. Earlier, authors have proposed and validated two types of annoyance
metric models based on the psychoacoustic subjective tests conducted in an office mock-up, and further developed software to implement the models. Here, the focus is on analyzing the response variations observed in the tests: i.e., the tendency for subjects to give relative annoyance ratings
instead of absolute ratings and differences in responses to longer and shorter stimuli. In addition, the approaches to incorporating response variations into the metric models are described. Note that the presented work is based on the studies of tonal office noises from service equipment,
with the fundamental frequencies of interest being 29.5, 60, 120, 240, 500, 750, and 1000 Hz. However, the proposed approaches for evaluating tonalness and addressing response variations may be applicable to the study of tonal noises from information technology equipment.
Dynamic property evaluation of hydraulic clamp based on analyzing the propagation characteristics of bending wave in hydraulic pipeline
Authors: Jin Jie , He Tong , Zhu ZhengBin , Gao PeiXin , Yu Tao
Published: December 2023

Hydraulic pipeline and clamp are important components of aviation hydraulic piping system. Determination of the dynamic properties of the clamp is of great significance to the analysis on the vibration characteristics of the aviation hydraulic piping system. In this study, an advanced
experimental method for determining the dynamic properties of the fixed clamp of aviation hydraulic piping system was proposed. The dynamic complex stiffness of the hydraulic clamp is determined by analyzing the propagation characteristics of the bending wave of the hydraulic pipeline with
clamp. Experiments were carried out using typical aluminum hydraulic pipeline and single-pipe grounded clamp specimens, and the dynamic characteristics of the hydraulic clamp were simulated using complex stiffness. The dynamic properties the hydraulic clamp were calculated by Newton-Raphson
iterative method, its frequency-dependent stiffness and loss factor were derived. The proposed method allows non-destructive continuous monitoring of hydraulic clamp components in engineering practice.
Experimental and theoretical basic research on sound absorption characteristics of foam materials with and without membrane
Authors: Sakamoto Shuichi , Satoh Takamasa , Tasaki Katsuhiko , Tanabe Kaito
Published: December 2023

A basic study was conducted to theoretically estimate the acoustic properties of a sound-absorbing foam material. Generally, the lattice of sound-absorbing foam materials contains membranes. Herein, for simplicity, a mathematical model was constructed assuming a cubic frame structure
as the basic frame structure of the foam, which included a membrane. Accordingly, the sound absorption coefficient was obtained and compared with the experimental results. In the mathematical model, the clearance in the frame structure (with membrane) was divided into elements and was approximated
as a clearance surrounded by two parallel planes, considering the exact shape of each element. Herein, the characteristic impedance and propagation constant of the approximated clearance were obtained and treated as a one-dimensional transfer matrix, and the sound absorption coefficient was
calculated using the transfer matrix method. For the experiments, the samples were fabricated using a 3D printer and the sound absorption coefficient was measured using a two-microphone impedance tube. Overall, the experimental and theoretical results exhibited similar trends.
Change in community annoyance at a vertiport by applying different approach/departure paths
Authors: Bauer Michael
Published: December 2023

The resent research on urban air mobility and its related air traffic noise is still focused on the understanding of air taxis' noise sources but already includes studies about potential future noise situations in the vicinity of vertiports. While the assessment of noise levels on the
ground is still connected to unknowns by the lack of reliable noise source data and missing numbers of real air traffic movements, questions about the potential noise impact due to these novel air transport systems are already being asked, also under the aspect of a public acceptance. This
study was performed to provide first answers. A realistic UAM use-case was investigated by noise simulations for a German community, delivering an insight how the annoyance in the small-town changes when applying different paths to connect the vertiport with its neighbor communities. The grade
of annoyance and the way it can be influenced through flight path optimization is also compared to the change of the population's ratio, exposed to certain noise levels on the ground.
Estimating the characteristic vibrations of a sound field in a room using coefficient of variation in the power spectrum of a decay-cancelled impulse response
Authors: Suzuki Ryoichi , Hoshi Kazuma , Hanyu Toshiki
Published: December 2023

Estimating the characteristic vibration distribution of a room sound field is difficult because the half-power bandwidth of the characteristic vibrations broadens due to room impulse response decay. Therefore, a coefficient of variation in a power spectrum of a decay-cancelled impulse
response is proposed for estimating the characteristic vibrations of a room sound field. In the decay-cancelled impulse response, only the decay of the impulse response is cancelled. Cancelling the decay narrows the half-power bandwidth, thus enabling a clearer estimation of the characteristic
vibration even in a sound field with a short reverberation time. In this study, sound fields with different characteristic vibration distributions were numerically simulated to investigate whether the coefficient of variation could estimate their difference.
Consideration on the uncertainty of audiometer calibration and pure tone audiometry
Authors: Cho Wan-Ho , Jung Sung-Soo
Published: December 2023

Pure Tone Audiometry (PTA) is the fundamental method for determining a subject's hearing threshold. The process is described in detail in ISO 8253-1, which also includes information about the measurement uncertainty of PTA in Annex A. Because the major value is based on the allowable
tolerance of each equipment and the assumed value with sufficient margin. In this study, the factors contribute to the uncertainty of audiometer calibration and PTA are investigated in the quantitative manner. There are two main groups of uncertainty components: the audiometer and the subject.
Components related to the audiometer include uncertainties in the stimuli of audiometer and it can be evaluated by the calibration of audiometer. The calibration process is thoroughly examined and the uncertainties in airborne audiometry are evaluated. The effect of components related to the
subject include the effects of head size on tension, ear shape on cavity volume, and headphone placement are observed by using an ear simulator and a dummy head.
Uncertainties of band sound levels when estimated from monochromatic outdoor sound propagation calculations
Authors: Ecotière David
Published: December 2023

Octave band and third octave bands sound levels are widely used in environmental acoustics, and most numerical models for outdoor sound propagation estimate them through the combination of several monochromatic calculations. As some of these models can be very time consuming when long
range distance calculations are needed, the number of monochromatic calculations performed for each band is often necessarily very limited. That induces uncertainties on the estimate of the noise level of the band that can be large when the spectrum amplitude varies widely inside a band. This
is the case for example when interferences due to ground effects occur. The paper presents estimates of these uncertainties depending on frequency band and on source-receiver locations. The uncertainties are evaluated thanks to a quasi Monte-Carlo technique from many calculations using a Rudnick
propagation model and a Latin Hypercube Sampling numerical experimental design for input parameters (source-receiver locations). The results provide practical indications on the minimum number of monochromatic calculations to do per band, in order not to exceed a given uncertainty level.
A study examining the long-term effects of aircraft noise on the surrounding residents before the opening of Long Thanh Airport
Authors: Nguyen Thu Lan , Nguyen Tran Thi Hong Nhung , Trieu Bach Lien , Morinaga Makoto , Morihara Takashi , Hiraguri Yasuhiro , Yano Takashi , Sasazawa Yosiaki
Published: December 2023

Long Thanh Airport (LT) is a new airport scheduled to open in 2025 and serve as the largest aviation hub in Vietnam. The residents are expected to experience adverse health effects from long-term noise exposure once LT begins operation. This study aims to serve as a basis for comparing
the impact of environmental changes before and after the opening of LT. This study assesses the health of the residents in ten residential areas under the planned flight paths of LT. Currently, before the new airport operates, environmental noise around LT is primarily caused by traffic noise
from nearby roads near the selected houses. The 24-hour A-weighted equivalent continuous sound level (LAeq) at a representative house in each area ranged from 51 to 72 dB. In August 2022, 641 residents were surveyed to assess their health conditions. It was found that traffic noise was the
most frequently cited environmental nuisance among the surveyed participants. However, the regression model considers contextual factors, noise exposure, and other factors impacting health and indicates that the health of the residents is associated with factors beyond noise exposure, such
as noise sensitivity, mobility, and attitude towards transport modes.
Modeling source directivity by solving inverse problems
Authors: Yatabe Kohei
Published: December 2023

Directivity is an important property of a sound source in the real world. Howerver, majority of the wave-based acoustic simulation does not reflect directivity of a source. One of the reasons is that modeling of source directivity is not a simple task and remains a matter of research.
In this talk, our attempts of modeling source directivity in time or frequency domains are briefly introduced.
The effect of amplitude-modulation methods and speaker gender on monosyllable articulation by distantly-presented bone-conducted ultrasound
Authors: Takahashi Naoya , Otsuka Sho , Nakagawa Seiji
Published: December 2023

Bone-conducted ultrasound (BCU) can be heard and can transmit speech information using amplitude-modulation (AM). Additionally, BCU can be heard even on distal-parts of the body; e.g., the neck, trunk, and upper limbs. Since transmission path of the distantly-presented BCU is much longer
and complicated than the ordinary-BCU presented to the head, it may contain tissues with strong nonlinearity like cartilages and generate some amount of self-demodulation components. Previous studies have indicated that the self-demodulation components contribute to improve the hearing of
distantly-presented AM-BCU, however, self-demodulation components are thought to be affected by AM-methods and modulator characteristics. In this study, effects of the AM-methods and the speaker-gender on distantly-presented AM-BCU hearing were assessed by Japanese mono-syllable articulation
testsin seven normal-hearing subjects. The articulation generally decreased as the presentation location moved away from the head, whereas the neck showed higher than the mastoid in some conditions. Effects of AM-methods on the articulationwere similarto those observed in the previous study
on ordinary-BCU (DSB-TC ≒ Transposed ≫ SSB, DSB-SC). Also, female-voice showed higher articulation than male-voice, especially in the distal locations. The results suggested that self-modulation components have significant effect, although the AM-methods affect dominantly on hearing
of the distantly-presented AM-BCU.
On the acoustical protection of acoustic balconies
Authors: Tang Shiu Keung , Leung Mors , Yip Sherman S. L. , Lee Rudolf Y. C.
Published: December 2023

Acoustic balcony is a recent development in Hong Kong for use as a noise screening device on high-rise building façades. It is in principle a balcony equipped with sound absorption materials (NRC 0.7) on its ceiling and side walls, as well as an inclined panel at its parapet.
Windows are installed on the space above the parapet to block the direct noise intrusion path from outside to the indoor. In the present study, a full size balcony mockup is adopted in an open-air laboratory and the sound transmission loss of the balcony at different sound source orientations
and elevations examined. A long linear loudspeaker array is used to mimic road traffic/ railway noise. The traffic/ railway noise transmission loss increases with source elevation under the effect of the inclined panel. For source elevation not larger than 45 deg, the difference between indoor
and outdoor noise levels in the presence of the acoustic balcony with adjusted traffic noise spectrum varies from 10 dBA to 18 dBA while with adjusted railway noise spectrum varies from 11 dBA to 17 dBA.
Additively manufactured rigid-flexible metamaterials for advanced sound control
Authors: Zhang Zhaohang , Krushinsky Dimitry , Krushynska Anastasiia O.
Published: December 2023

Additive manufacturing opens promising perspectives for realizing acoustic metamaterials to control sound in multiple application scenarios. Especially attractive are hybrid flexible-rigid 3D-printed metastructures as they combine the advantages of rigid designs (e.g., load-bearing
performance) and an increased number of structural degrees of freedom owing to flexibility. Here, we discuss the potential of 3D-printed flexible plastics and resins for extending the absorption functionality of hybrid acoustic metasurfaces to broadband low-frequency regimes and achieving
switchable absorption in flexible lattice acoustic metamaterials. Besides, we show how metamaterial patterns can control sound generated by flapping flexible wings. The proposed metastructures are studied numerically, manufactured by means of FDM or SLA 3D printing, and tested in the lab.
Experimental studies of the impact of amplitude modulation (AM) and tonality on the annoyance of wind turbine noise in the low frequency (LF) range
Authors: Wszołek Tadeusz , Pawlik Paweł , Małecki Paweł , Kłaczyński Maciej , Mleczko Dominik , Czapla Marcjanna , Stępień Bartłomiej
Published: December 2023

Amplitude modulation (AM) testing is most often limited to the band from 100 Hz to 800 Hz. The impact of AM and tonality on the annoyance of wind turbine (WT) noise in the frequency range below 100 Hz was undertaken as part of the work. In many works, complaints about the annoyance
of WT noise in the low frequency (LF) band are raised, although the energy levels in this band do not exceed the threshold of perception. One of the reasons for such complaints may be AM and tonality. Acoustic signals were recorded in the band from 1 Hz to 20 kHz, at distances from 250 to
1500 m from the turbine at various wind speeds. From the recorded results, samples with the presence of AM and samples with tonal components were selected. The modulation depth, tonality or frequency modulation (FM) were determined for each sample. Preliminary listening tests were also carried
out, in which the stimulus was the samples of recordings with AM and tonal components. The listening range was limited to the LF band. Preliminary studies showed no significant differences in noise perception between these samples. Further research is planned with recordings of greater tonality
and AM depth.
Design of coupled Helmholtz resonator with rectangular enclosure to mitigate low frequency noise in recording booths
Authors: Ghanouni Farbod
Published: December 2023

This study summarizes theoretical and experimental findings for low frequency noise mitigation in small recording booths using coupled Helmholtz resonators. The room acoustical resonance modes were identified using ANSYS simulation software for the recording booth. An experimental setup
validated the existence of the different low frequency modes and variation from theoretical results due to the enclosure wall's surface material. Microphone and speaker system were used to measure the room frequency response at the resonant frequencies. Piezoelectric sensors were placed at
different positions within the room to determine the location of resonance peaks and the optimized position for the coupled Helmholtz resonator. The effects of damping on the Helmholtz resonator frequency response and deviation from theoretical design formulae were explored. The resonator
apparatus proved to attenuate noise to half as loud in the selected low frequency range within the recording booth.
Development of a UAV Test Stand
Authors: Schmal Jared , Herrin D. W. , Comesaña Daniel Fernández
Published: December 2023

Performing acoustic measurements on a multicopter in a confined space, such as a small anechoic chamber, can be an extremely difficult and time-consuming process. Inherent risks to the vehicle, laboratory equipment, and technicians are present when a multicopter is operated. In addition,
standard multicopter maneuvers are difficult to conduct due to spatial constraints, and obtaining near field acoustic measurements is dangerous due to the inherent dynamic variability that occurs during flight. A UAV test stand was developed to remove these limitations and allow for rapid
and safe acoustic measurements in a controlled environment. The design, development, and initial measurements are discussed. The performance and acoustic response of the brushless electric motors and propellers are assessed to examine the effectiveness of the test stand. The contribution noise
from the test stand and a measurement grid are evaluated, as well as the influence of stationary propeller testing. Lastly, the pros and cons of using a test stand for UAV measurements are discussed.
Relation between Acoustic Absorption Performance and Flow Field around Perforated Plate with Cross Flow
Authors: Yamada Ryouya , Maeda Syouta , Hamakawa Hiromitsu , Kurihara Eru , Hayashi Hidechito
Published: December 2023

The present paper focuses on the relationship between the acoustic absorption performance and the flow field around a perforated plate with cross-flow. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. As
the flow velocity passing through the orifices increased, the peak level of the acoustic absorption coefficient increased in some cases. We observed the flow field around a perforated plate by flow visualization using a laser. The vortices were clearly formed downstream of the orifices due
to the incident sound of pure tone. We discussed the relationship between the vortex and the acoustic absorption performance of perforated plate with a cross flow.
Modelling and analysis for the dynamic behavior of 6-DOF motion platform used for simulating aerospace mechanical environment
Authors: Ma Longyu , Chen Zhizhou , Jing Haitao , Ye Zhexiao , Yang Zhiying , Shi Junwei , Ma Xiaolong
Published: December 2023

As high carrying capacity, high frequency response and high precision control performance are presented, the 6 degree of freedom (DOF) motion platform is chosen as the aerospace device to implement mechanical environment simulation experiment on the ground. In this paper, a dynamic
model of the 6 DOF motion platform is firstly developed based on the Newton-Euler method. Then the attitude determination and the driving force are analyzed by solving the dynamic equations. Furthermore, a parametric modelling method for the 6 DOF motion platform is proposed and applied to
obtain the expansion amounts and the driving forces of the 6 hydraulic rods in the motion platform by adopting the Adams software. Results show a good agreement with the computation results of the theory dynamic model, which demonstratesthe validity of the proposed modelling method for analysis
of the dynamic behavior of the 6-DOF motion platform.
One sight on sound generation and absorption by vortices
Authors: Nishimura Masaharu , Iwaki Yuka , Goto Tomonobu
Published: December 2023

Vortices generate sound and absorb sound. A. Powell and M. S. Howe deduced the equations and showed that the exterior product of vortex and local velocity took part in sound generation and absorption. However, it is difficult to image its physical phenomena. In this paper, as one example,
the interaction of sound and vortices at the throat of a cavity with grazing flow is investigated by CFD simulation. As the results, it is found that sound absorbing regions and sound generating regions are locally distributed and moving. It is also found that when counterclockwise vortices
turn to the left, they absorb sound and when they turn to the right, they generate sound. Based on these results, 'Floating Vertical Bar Model (FVB Model)' is proposed to image the sound generation and absorption phenomena, in which a vortex is simulated as a bar floating vertically on the
water surface, because a vortex has coherent structure along its axis like a bar. When a vortex (a bar) is accelerated perpendicular to its axis, pressure fluctuation (water wave) is easily generated. And when sound wave (water wave) shakes a vortex (a bar), sound energy is absorbed by a vortex
(a bar) motion.
Study of low-frequency noise suppression effect inside acoustic cavities by applying piezoelectric nonlinear energy sink
Authors: Shao Jianwang , Wu Bingxin , Luo Qimeng , Zhao Huihong , Wu Xian
Published: December 2023

In this paper, the piezoelectric nonlinear energy sink (NES) is used to suppress the radiated noise from a thin plate, and the targeted energy transfer (TET) characteristics and mechanism of the coupled system of two piezoelectric NESs and a thin plate are analyzed, and the coupling
model of the system with the acoustic cavity, rectangular thin plate and piezoelectric NES is established. The parameters of the piezoelectric NESs are adjusted according to the excitation amplitude, and then applied to the rectangular thin plate. The numerical results show that the piezoelectric
NES causes the system to undergo strongly modulated response (SMR) and the resonance peak of radiation noise is effectively suppressed. It provides a new technique for passive control of low-frequency noise.
A robust auxiliary noise power scheduling strategy for online secondary path modeling in active noise control systems
Authors: Duan Zhehua , Han Ning
Published: December 2023

Auxiliary noise injected in active noise control (ANC) systems for online secondary path modeling (SPM) contributes to the residual noise, and thus deteriorates the noise control performance of ANC systems. Moreover, sudden changes in secondary path may lead to easy divergence of the
existing online SPM methods. This paper improves the existing methods from three aspects to further mitigate these problems: 1) the noise power is varied on the basis of the convergence status of SPM filter so that large-power noise is injected at the start or when secondary path changes and
the power is reduced as the filter converges. 2) a novel ON/OFF controlling strategy is used in the method so that the noise injection is suspended at the optimum point when the modeling accuracy is sufficient. 3) continuous check for error outliers is applied in the method to detect changes
in secondary path so that the injection of noise can be reactivated in the case of path perturbation. Comparative simulations show the effectiveness of the improved method both in convergence and noise reduction performance. In addition, the improved method is robust against sudden changes
in secondary path.
Partial Problem-based Learning on Open-Source Acoustics Software Education for Marine Engineering Degree Programme
Authors: Chin Cheng Siong , See Simon
Published: December 2023

Airborne noise from operating equipment onboard offshore vessels negatively affects the crew members working and staying on the vessel for extended periods of time. However, many students pursuing a marine engineering degree are unequipped to handle this problem because acoustics and
its application to marine systems are currently not a part of many curricula. In addition, difficulties in teaching acoustics in the marine engineering degree course arise from the lack of knowledge and skills among teaching staff from various mechanical, naval marine, architecture, and offshore
engineering backgrounds. Hence, a new curricula model using a partial problem-based learning (PBL) approach is proposed to improve student learning in room acoustic. Studying room acoustics using open-source software such as PsySound3, and AARAE provides students with hands-on experience in
room acoustics modeling and simulation in the marine engineering degree programme. The overall feedback from the students indicated that following the partial PBL initially was quite challenging. Some instructors felt that PBL training was insufficient to improve their understanding of PBL
activities. However, most students and instructors gave positive feedback on using information technologies to create more interest in learning and teaching acoustics.
Relationship between sound environments and worker's impression evaluation in open-plan offices Part 1: Development of the survey system and summary of the survey results
Authors: Togashi Kengo , Araki Takumi , Sugahara Akiko , Nagasawa Yasuhiro , Hiraguri Yasuhiro , Harada Kazunori , Iwakiri Yukinobu
Published: December 2023

In recent years, the adaption of open-plan offices is increasing as they effectively improve intellectual productivity by fostering communication among workers. Many previous studies have clarified the relationship between a sound environment and intellectual productivity by having
subjects work in constrained spaces such as meeting rooms or laboratories. However, little research has been conducted on the effects of a sound environment in office spaces where multiple workers actually work. In an open-plan office, the goal of this study is to clarify the relationship
between a sound environment and a worker's impression evaluation. The purpose of this paper is to introduce our originally developed real-time sound environment measurement system and to describe the results of a measured survey conducted in an actual open-plan office.
Exploring the pediatric intensive care unit soundscape from health professionals' perspective
Authors: Orhan Cemre , Yilmazer Semiha
Published: December 2023

This paper aims to conduct qualitative research that explores health professionals' soundscape perceptions in Pediatric Intensive Care Unit (PICU). The building is close to the city airport, university campus, and city center in Trabzon, Turkey. Therefore, besides its alarm-driven auditory
environment, there are several different sound sources that people are exposed to. PICU has single-bed units with a maximum capacity of seven ICU beds for children (age < 18 years). This paper uses the Grounded Theory (GT) to explore ICU health professionals' perceptions of built and auditory
environments, categorize ICU soundscapes, and generate a conceptual framework. Following the ISO/TS 12913-2/3, semi-structured interviews were conducted and analyzed to discover the subjective responses. Results showed that the most dominant sound sources are human-based and technology-based
sounds. Similar to previous soundscape studies, the context was found as the framework's main category. Health professionals responded neutrally to alarms and negatively to irrelevant sounds that cause concentration loss and disturbance.
Ventilating noise barrier with slow wave propagation metamaterial
Authors: LIANG Shanjun , FU Yuyu
Published: December 2023

There has been rapid development of acoustic metamaterials over the past decades, which provide more flexible and effective alternatives to conventional acoustic applications in the field of noise insulation. Recent approaches resolve the conflict between noise insulation and ventilation
with partially open meta-structures. Such a binary design eliminates the monopolar and dipolar modes, leading to a total reflection boundary. It holds huge potential in practical scenarios. More simple structures and a broader operating bandwidth are highly desirable to enhance its applicability.
This work adopts a binary structure to tune the surface response: open areas with air and slow wave propagation layers with helical-structured metamaterial. These two phases alternate along the radial direction, forming a concentrically layered ventilating insulator. The numerically optimized
metamaterial performs efficiently in a wide frequency band and has been validated through experiments.
Comparison between noise annoyance and noise sensitivity
Authors: Chikai Manabu , Hirakawa Susumu , Sato Hayato , Hiramitsu Atsuo , Kimura Kenta , Terasawa Hiroko , Mahn Jeffrey , Müller-Trapet Markus , Cunha Iara Batista da , Sato Hiroshi
Published: December 2023

This study examined the relationship between noise sensitivity and noise annoyance. As part of a collaboration between the National Institute of Advanced Industrial Science and Technology in Japan and the National Research Council Canada related to the acoustic requirements for dwellings
intended for aging in place, a pilot subjective study of noise annoyance was conducted. Sixty participants in the subjective study were asked to also complete a shortened Weinstein Noise Sensitivity Scale. The results were divided into two groups based on their hyper- or hypo-sensitivity to
noise. The results showed that the noise annoyance of impact sound was perceived differently by the hyper-sensitivity group and the hypo-sensitivity group.
Vibration analysis of a six-degree-of-freedom rotor supported on two different deep groove ball bearings with waviness on races
Authors: Yang Zeli , Zuo Shuguang
Published: December 2023

The maximum speed of the motor of the vehicle's electric drive system is gradually increasing. At high speed, the influence of vibration and noise of the bearing rotor system on the electric drive system cannot be ignored. The existing research literature mainly focuses on the vibration
characteristics of bearings or only considers the vibration of rotors supported by the same bearing type. However, many rotors are supported on two different bearings in practical applications. In this paper, a dynamic model of a bearing rotor system considering six degrees of freedom is established,
taking into account the complexity of the different types of support bearings on both sides. In addition, waviness on the surface of the inner and outer races of the bearing is considered in the model. The accuracy of the model is verified by comparing it with the results of the model in the
published literature. The research results show that when the types of bearings on both sides are different, the vibration characteristics of the system are more complex than that of the same type of bearings, with more harmonic components of the vibration and additional sideband frequencies
appearing.
Direct sound field estimation based on sound source modeling with sparse equivalent sources
Authors: Tsunokuni Izumi , Matsuhashi Haruka , Ikeda Yusuke
Published: December 2023

The measurement of multi-point room impulse responses (RIRs) is challenging because it requires many microphones or a microphone traverse system. In our previous study, we proposed a spatial extrapolation method to measure early RIRs by the locally-positioned microphones. However, the
estimation accuracy was degraded at a far distance from the microphones owing to the directivity of the sound source. In this study, we proposed a modeling method to estimate a direct sound field using a source radiation model based on the sparse equivalent source method. First, the source
radiation was modeled using an enclosed microphone array. Then, we modeled the direct sound field using locally positioned microphones. The evaluation experiment was conducted in an anechoic chamber under 2.5D condition.
Investigation of the acoustic properties of underwater rainfall noise measured by a bottom-mounted hydrophone and its application to deep learning to classify and estimate rainfall
Authors: Kim DongWook , Lee Dae Hyeok , Choi Jee Woong
Published: December 2023

Although the ocean covers more than 70 % of the Earth's surface, it is difficult to measure precipitation over the ocean due to the technical limitations of platforms such as surface buoys and satellites. Recently, the estimation of precipitation has been tried using the underwater
sound generated by rainfall. In this talk, we present the results of comparing underwater noise and rainfall with and without precipitation using the underwater noise and rainfall data provided by OOI (Ocean Observatories Initiative, USA). The acoustic data was acquired by a bottom-moored
hydrophone at a depth of 80 m off the coast of Oregon, and the rainfall data was measured from a rain gauge installed on a surface buoy. The 1-minute averaged power spectral densities for ambient noise were computed for 26 days from 5 - 30 April 2018, which were compared with rain rate and
wind speed. Based on the comparison results, the presence or absence of rainfall was determined through a pattern recognition neural network, and finally, the amount of precipitation was estimated through multiple linear regression analysis.
A study on the influence of reflective surfaces on sound source localization using distributed acoustic measurement equipment
Authors: Takeuchi Ren , Ikemi Itsuki , Harada Kazunori , Sugahara Akiko , Hiraguri Yasuhiro
Published: December 2023

This research aims to develop a system that will detect sound source localization in a broad area using cross-correlation functions for signals from distributed microphone arrays, which is difficult with conventional methods that use microphone arrays. For the localization of sound
sources, four microphones were distributed in an anechoic room. Based on the result, the system was able to estimate the sound source position within a plus or minus 20 mm of accuracy. To verify the accuracy of the system, a reflective surface was set up in an anechoic room to confirm the
effect of reflected and diffracted sound. No significant increase in error was observed when the reflective surface was behind the microphone as viewed from the sound source. However, the estimation error increased when diffracted sound was present.
Data-driven estimation of sound absorption coefficients considering the positions of microphones
Authors: Arai Hiroto , Sato Gen , Ikeda Yusuke
Published: December 2023

The sound absorption coefficient of walls is important to simulate the sound reflections in a room. However, measuring the sound absorption coefficients in detail requires many measurement points along the wall surface. Recently, machine-learning-based estimation methods have been proposed
for the sound absorption coefficients using the room impulse responses as training data. In this study, to obtain the sound absorption coefficients of each wall surface with free microphone placement, we proposed the machine learning-based estimation with the room transfer functions and its
measurement positions. The positional information of microphones is provided to the network in the mask data format. In the two-dimensional simulation experiments, we evaluate the estimation accuracy of the proposed method compared to the fixed microphone arrangement.
Signal processing applications for sound field measurements using instantaneous array input
Authors: Iwami Takahiro , Omoto Akira
Published: December 2023

Most existing acoustic signal processing techniques have been developed in the frequency domain. These techniques are suitable for single-frequency signals, but most actual sound fields are wideband. To apply frequency-domain techniques to wideband signals, it is necessary to wait the
time required for processing before performing the discrete Fourier transform, and then apply processing to each frequency bin. This study describes acoustic signal processing techniques using the instantaneous input of a microphone array are described. These techniques are suitable for real-time
implementation because they avoid the above disadvantages. The limitations and disadvantages of methods using only instantaneous information are also discussed.
Numerical investigation on the sound scattering characteristics of amorphous structures by using Voronoi tessellation
Authors: Hamatani Kouki , Sugahara Akiko , Hiraguri Yasuhiro
Published: December 2023

Amorphous (non-periodic) materials, such as glass, lack long-range order and are macroscopically disordered and isotropic. Consequently, amorphous structures have the potential to scatter the incident waves in various directions, unlike crystal structures that exhibit specific directional
reflection. The purpose of this study is to clarify the characteristics of an acoustic diffuser using an amorphous structure. First, some amorphous samples with different fineness and slope angles were prepared using Voronoi tessellation. Then, their scattering properties were numerically
calculated by the finite element method. In this paper, we discuss the influence of geometric differences on the scattering coefficient and directivity characteristics of the reflected sound.
Indoor soundscape design of autonomous vehicles that comprehensively applies acoustic characteristics of architectural space type
Authors: Yoon Hyowon , Lee Haram , Santika Beta Bayu , Luo Ylhong , Jeon Jin Yong , Kim Juin , Park Dongchul
Published: December 2023

According to the paradigm shift in the indoor space design of future autonomous vehicles, the indoor space of the vehicle was classified according to the purpose of use and the optimal soundscape design for each type was proposed. The vehicle selected for the measurement can be the
basic type of future autonomous vehicles, a relatively wide van suitable for building space investigation, and the space target was selected as spaces for listening to music, working (meeting), and resting. Accordingly, for the soundscape design, an audible sound source was produced and used
for evaluation by conducting a sound field survey and computer simulation inside the vehicle. The indoor soundscape of the vehicle was evaluated by providing binaural sound source in the auditory test environment. The evaluation indicators were selected based on the indoor soundscape parameters
in the architectural spaces such as concert halls and office buildings.
Analyze the effect of stacking sequences on nonlinear acoustic signatures in GFRP composite laminates and quantify the delamination using subset simulations
Authors: Gangwar Akhilendra Singh , Joglekar Dhanashri M.
Published: December 2023

Non-destructive evaluation(NDE) techniques that use nonlinear wave-damage interactions have recently attracted considerable attention for their heightened sensitivity in detecting incipient damage. In this context, a numerical model based on the Finite Element (FE) method has been developed
to simulate the nonlinear interaction of guided waves through delaminations in angled glass fiber-reinforced polymer (GFRP) laminated composites. This study aims to investigate the effects of stacking sequences on nonlinear acoustic signatures in GFRP composite laminates and quantify the delamination
extent using subset simulations. The stacking sequences of GFRP composite laminates have been varied to analyze their influence on the amplitude of higher harmonic components. The results suggest that the stacking sequences significantly affect the amplitude of nonlinear acoustics. Moreover,
the subset simulation technique has been employed to quantify the extent of delamination in the GFRP composite laminates. The proposed approach can effectively quantify the effects of delamination and provide insights into the damage mechanism of composite laminates. The results can help optimize
the design of composite structures to improve their performance. This study highlights the importance of nonlinear wave-damage interactions in NDE techniques. It offers a valuable contribution to the ongoing efforts to enhance the reliability and efficiency of composite structures.
Earplug fit-testing system applying pure-tone audiometer
Authors: Yokoyama Sakae , Kobayashi Tomohiro , Takeda Aoi , Nakaichi Takeshi
Published: December 2023

As for the sound attenuation measurement method of hearing protectors, such as earplugs and earmuffs, the real-ear attenuation at threshold (REAT) method is established by some standards such as ISO, ANSI, AS, etc. As known, however, sound attenuation differences between workers wearing
protectors in real occupational noise fields are not small due to personal size-fitness or wearing conditions of hearing protectors. Although personal hearing protector fit-testing systems have been developed and standardized in Western countries, the systems have not yet been standardized
in Japan, so they are not applicable easily. The authors tried to apply the pure-tone audiometric system equipped with circumaural earphones used for a medical check-up to the fitting system for earplugs on this occasion, where the Japanese guidelines for preventing noise-induced impairments
were revised for the first time in about 30 years. This paper describes the overview of the earplug fit-test system applying the audiometer and trial test results of sound attenuation ratings by the proposed system.