Calculation of noise reduction and acoustic impedance of the duct system is needed for the one-port source model, which is widely used in the field of duct acoustics for extracting the source characteristics and predicting the radiating noise at the open end. The flow field in the duct influences the acoustic characteristics when the flow velocity is relatively high. Recently, the time domain method

This study aimed to investigate the associations between physical acoustic factors, job characteristics, and job satisfaction. Acoustic measurements and questionnaire surveys were conducted in 12 open-plan offices. Active noise levels (LAeq,8-hour), reverberation time (T20), and speech privacy-related measures such as D2,S and Lp,A,S,4m were measured at each office. A total of 324 employees then completed

This paper aims at consolidating research dealing with vibroacoustics of periodic media. The main goal of this work is to develop and to validate tools for the design of global vibroacoustic treatments based on periodic patterns, allowing passive control of acoustic paths in layered concepts. To this aim, some enhancements are introduced to the state of the art on the study and the design of Biot-modeled

This paper proposed a type of lightweight multilayer honeycomb membrane-type acoustic metamaterials (AMs) and the transmission loss is studied experimentally. It is demonstrated that lightweight honeycomb sandwich panel AMs can break the mass law and obtain the great sound transmission loss at a light-weight. The mass per cell area of the metamaterial structure has 0.29 kg/m2 only and the total thickness

The preeminent merit of function expansion bilinear (FEB) filters is their ability to represent nonlinear distributions for active noise control (ANC) systems. Unfortunately, the huge computational burden and bounded input bounded output (BIBO) unstable problem hinder its practical applications. In this paper, we propose a general channel reduced efficient implementation algorithm for FEB filter and

Traditional Chinese performance buildings and performing arts are different from those in the west. However, sound quality evaluation factors for western halls have been used in traditional Chinese performance buildings for a long time. In this study, grounded theory was used to establish a sound quality evaluation system for traditional Chinese performance buildings. The subjective evaluation system

Fundamentally, Structural Health Monitoring (SHM) of mechanical systems is essential to avoid their catastrophic failure. The first key contribution of this paper is presenting a new method for damage detection of mechanical systems in presence of the uncertainties such as modeling errors, measurement errors, varying loading conditions and environmental noises based on Finite Element (FE) model and

Excessive interior noise in high-speed trains affects riding comfort of both drivers and passengers, therefore, it is a key indicator of product competitiveness for manufacturers. Past academic researches on train interior noise control focus primarily on mechanisms and characterisations of noise sources and vibro-acoustical behaviours of car-body structures, and these two aspects are often dealt with

Concrete causes substantial attenuation on ultrasonic guided waves during their propagation within a pipe. The circumferential position of the defect is even more difficult to detect in a concrete-covered pipe with a small diameter. This paper reports that the axial and circumferential positions of a circumference defect in a small-diameter concrete-covered pipe can be identified by moving the half-covered

The main goal of present work is to create a comparative evaluation methodology based on the correlation between the objective parameters of traditional acoustics and the psychoacoustic subjective parameters investigated with listening tests. This led to the definition of a quality index for kitchen hoods calculated from measurable objective parameters to provide guidance on the ultimate sound perception

High pressure gas venting operations, known as blowdowns, such as from steam driven power plants, and gas pipelines, are known to produce significant noise. Such noise can be of concern for those working or living near such operations. Therefore, the ability to accurately predict blowdown noise, and prescribe appropriate safety equipment, and safe exposure times, is of practical interest. The present

The higher performance of the guided wave technique for non-destructive testing (NDT) and structural health monitoring (SHM) on large-scale engineering structures is still a requirement in industries. In this paper, the unidirectional excitation function of guided waves by adding many rings of transducers (even or odd number) is described to enhance the wave power output of the inspection system. A

A piezoelectric feedback system for active noise control (ANC) of vehicle interior noise is built in this paper. Firstly, a mathematical vibration model of a typical vehicle-used plate with piezoelectric patch is derived for revealing piezoelectric mechanism. An improved filtered-x least mean square (FxLMS) algorithm based on the discrete wavelet transform (DWT), so-called DWT-FxLMS, is presented.

Deep learning denoising models can automatically extract underwater heterogeneous information data features to improve denoising performance through an internal network structure. In the present study, a novel stacked convolutional sparse denoising autoencoder (SCSDA) model was proposed in this paper to complete the blind denoising task of underwater heterogeneous information data. Specifically, for

This paper aims to explore the influence factors of speech intelligibility and the applicability of the speech transmission index (STI) in large spaces, where the sound energy is unevenly distributed and non-exponentially decays. The subjective speech intelligibility tests were conducted in Mandarin (China mainland) in two large spaces with volumes of 97,000 m3 and 246,000 m3. Objective indicators

During the manufacture and processing of products, flatness is an important indicator of product quality. At present, flatness detection methods can be classified into contact and non-contact methods. Contact detection requires mutual contact with the test object, so the detection efficiency is low and it is easy to cause damage to the product. In the non-contact detection method, the accuracy of the

An improved CNN is proposed for the diagnosis of defects in components of a centrifugal pump. The improvement is attained by modifying the cost function of CNN. For defect identification, first, grey scale acoustic images are obtained by processing acoustic signals using analytical wavelet transform (AWT). Second, a new entropy based divergence function, a type of regularization function is introduced

The adoption of the environmental sound classification (ESC) tasks increases very rapidly over recent years due to its broad range of applications in our daily routine life. ESC is also known as Sound Event Recognition (SER) which involves the context of recognizing the audio stream, related to various environmental sounds. Some frequent and common aspects like non-uniform distance between acoustic

In this paper the improvement in performance of automatic speech recognition (ASR) system is achieved with help of pitch dependent features and probability of voicing estimated features. The pitch dependent features are useful for tonal language ASR system. Punjabi language is highly tonal language and hence here we are building ASR system for Punjabi language with pitch dependent features and probability

Partial microperforated panel (MPP) structures have been proposed for MPP with low sound absorption properties. Its purpose is to improve the sound absorption performance of the MPP in certain frequency bands. The structure was studied by the transfer matrix method, finite element simulation and experimental test. The results show that the three kinds of curves, that is, theoretical and simulation

A novel plenum window with incorporation of sonic crystals (SCs) was investigated using numerical and experimental methods in the present studies. Additional insertion loss (IL) that could be obtained by the 3 SCs was computed through a commercial software and was validated through experimental results from reverberation rooms. Experimental data showed that the SCs could attenuate more traffic and

Fibonacci Series and Music are related in many ways. Even though Indian Classical Music (ICM) is known to be based on Just Intonation rather than equal tempered, not much attention has been given to inflections on the notes, which are integral part of the notes themself. In this work an interesting relation between Fibonacci series and Just Intonation in ICM has been found. Further, discrete version

Seabed sediment classification using acoustic remote sensing technique is an attractive approach due to its high coverage capabilities and limited costs compared to taking samples of the seafloor. This paper focuses on backscatter intensity correction, sonar image quality improvement, and classifier construction, which aims to improve the accuracy of seabed sediment classification. The details are

Source localization and quantification by an acoustic array of microphones depend to a great extent on an accurate knowledge of the antenna position towards the radiating device. The present work details a methodology to determine the location of the microphones in relation to an object of study, starting from its geometric shape and that of the array, in order to reproduce an experimental configuration

A method to analyze the acoustic characteristics of periodic structures is investigated. When a continuous boundary condition is introduced, the field in which a plane wave is normally incident on the periodic structure can be easily analyzed by the finite-difference time-domain (FDTD) method. However, when a plane wave source is obliquely incident, field mapping with auxiliary variables is necessary

Vehicle horns must satisfy sound pressure level regulations in each country. Therefore, it is essential to optimize the horn location inside the front grille of the vehicle to maximize sound transmission through the grille opening and adhere to sound pressure level regulations. This study developed a computational method to determine optimal horn locations during early stages of vehicle development

Twin-screw compressors are widely used in refrigeration systems, but typically suffer from severe vibration and noise due to pulsing gas flow during operation. Gas pulsation is the main noise excitation source of screw compressors, presenting significant fundamental harmonic characteristics. This study examined noise control technologies for screw refrigeration compressor designs, such as acoustic

New-borns are exposed to high noise levels inside infant incubators. Some authors suggest that these noise levels are amplified by the reverberant nature of the materials that compose incubators. In this paper, the impulse response and the reverberation time of an incubator with standard dimensions were calculated. Two incubator configurations were evaluated, with and without mattress, under two measurements

Due to the increasing awareness around the environmental crisis and the depletion of petroleum resources, together with the inherent issues connected with the use of composite systems such as their disposal and recycling and the health problems associated with the use of some raw materials, new legislative rules on global scale have been promulgated to fight environmental issues and will be hoping

Despite the increasing interest in Micro-perforated panels (MPPs) for various noise control applications, the acoustic behavior of MPP liners in flow ducts has not been fully apprehended. On the top of this is the lack of understanding on the influence of various design arrangements and system parameters on the performance of MPP-based acoustic silencing devices. Incorporating previously developed

Although spatial hearing is of great importance in everyday life, today’s routine audiological test batteries and static test setups assess sound localization, discrimination and tracking abilities rudimentarily and thus provide only a limited interpretation of treatment outcomes regarding spatial hearing performance. To address this limitation, we designed a dynamic sound field test setup and evaluated

The closing sound of a car door is objectively not related to the intrinsic quality of the vehicle but it is an important subjective parameter for vehicle evaluation. For automotive developers, it is very interesting to deepen this phenomenon and to define a methodology to understand the influence of several parameters on door-closing sound quality. The aim of this paper is to evaluate the possibility

Transport noise is the dominant noise source in urban areas. Its impacts on people at their residential locations are included in economic appraisal in the UK and many other countries, and guidance and analysis tools were developed for the valuation of the impacts. However, for transport noise impacts on people in public urban spaces, e.g., urban streets, squares and parks, there is still a lack of

Osteoarthritis (OA) is a degenerative joint disease, which is usually accompanied by inflammation. The aim of this study was to evaluate the anti-inflammatory effect of Low-intensity pulsed ultrasound (LIPUS) on OA. Fibroblast-Like Synoviocyte (FLS) were stimulated by LIPUS with/without interleukin (IL)-1β to evaluate inflammatory responses. The results showed that IL-1β could effectively induce the

In this study, we evaluated deep convolutional neural networks for classifying the calls of 24 birds and amphibian species detected in ambient field recordings from the tropical mountains of Puerto Rico. Training data were collected using a template-based detection algorithm followed by a manual validation process. As preparing sufficient training data is a major challenge for many deep learning applications

Phased arrays are increasingly employed in clinical high-intensity focused ultrasound (HIFU) systems for treatment of uterine fibroids. However, the electronic steering range of current phased arrays is insufficient to cover a symptomatic uterine fibroid. This study proposes a method to augment the focal steering range for HIFU treatment of uterine fibroids. Geometric focus can be shifted by tilting

A well-known problem in speech communication is the occurrence of acoustic echo in hands-free telephony. There are several classical adaptive filters that have been used as a stand alone approach for linear acoustic echo cancellation(AEC). A common assumption in most AEC techniques is that the echo path is linear. However, in real scenarios, owing to distortions introduced by other acoustic artefacts

Inventorying and monitoring which bird species inhabit a specific area give rich and reliable information regarding its conservation status and other meaningful biological parameters. Typically, this surveying process is carried out manually by ornithologists and birdwatchers who spend long periods of time in the areas of interest trying to identify which species occur. Such methodology is based on

In the last decade, the sound quality of electric induction motors is a hot topic in the research field. Specially, due to its high number of applications, the population is exposed to physical and psychological discomfort caused by the noise emission. Therefore, it is necessary to minimise its psychological impact on the population. In this way, the main goal of this work is to evaluate the use of

For high-frequency digital signals to be transmitted over long distances, the basic digital signal needs to be modulated with a high-frequency carrier. In this case, the baseband digital signal is called the passband signal. In particular, in wireless communication systems or ultraviolet or infrared communications, transitional band digital modulations are used. The most commonly used transition band

Melody extraction from polyphonic music is still an open problem due to the intrinsic complex nature of real-world music. Pitch estimation and voicing detection are two critical subproblems in melody extraction. In this paper, a joint pitch estimation and voicing detection method is proposed. More specifically, the unvoiced case is also assigned with one class label, the same as semitone level pitch

The low frequency noise (LFN) from road traffic is a typical urban environmental noise pollution. It is difficult to be eliminated by traditional noise control techniques. Sound masking has been proved to be an available way to improve the noise perception. This study aims to explore the effect of music masking on LFN from the aspects of loudness and spectral centroid. One music clip, Butterfly Lovers

Impact noise is increasingly becoming an important issue both in terms of technologies for its reduction and in terms of its perception inside buildings. In fact, a high level of noise clearly affects indoor comfort and liveability of confined spaces. For this reason, this study focuses on the influence which the static load over time impacts on the resilient material of a floating floor and on its

Room acoustic parameters of open-plan offices, e.g. ceiling, wall, screen, and furniture absorption, and screen height between workstations, affect strongly sound pressure level (SPL) of speech. The effect depends on the distance from the speaker. The aim of this experimental study was to examine the effect of ceiling, wall, and screen absorption, and screen height on the spatial decay of speech both

Impact sound performance below 100 Hz forms part of a design criterion that is particularly important for multi-story timber buildings. An ISO tapping machine, which is predominantly used for impact sound measurement, has properties that may result in less measurement accuracy in the low frequency range, down to 20 Hz, than in its traditional measurement range above 100 Hz. The characteristics of the

In this paper, a novel composite acoustic metamaterial comprising of periodic multi-resonator and voids is proposed, in which the periodic multi-resonator and periodic voids are embedded into the sound absorption layer and the sound insulation layer, respectively. The different arrangements for the two layers are designed, and the sound absorption behaviors of the proposed combinations immersed in

With the gradual deepening of coal mining, under the action of stress concentration, coal and rock in deep stopes are prone to dynamic disasters such as rock burst and large area pressure. Therefore, using the fracture characteristics of the rapid fracture stage of coal rock mass, the evolution process of damage and fracture of coal rock mass under stress concentration conditions can be effectively

The focus of this study is on locating surface and sub-surface defects that occur in rail tracks using Rayleigh waves that were emitted and sensed by a fully non-contact laser transduction system. As the quality of received signals varies with respect to the rail surface characteristics, spotting the reflection from a defect can be extremely challenging. These signals are in general contaminated with

Participatory measurement of environmental sound levels has gained interest in recent years. The calibration of measuring instruments is currently the main technical limitation. It is often the responsibility of the users and can be a potential source of error or add costs to the measurement protocol. In this article, a calibration protocol is proposed, based on the low variability of the average noise

For over a decade, most wind turbines have worked by adapting their rotation speed to that of the wind. This operating method, now widely used, allows optimal tip speed ratio to be achieved whatever the weather conditions, and in fact produces much better output than stall controlled turbines, particularly in calm weather conditions. However, this improvement means that monitoring systems are required

In this paper, the sound transmission loss (STL) of multi-layered elastic micro-perforated plates (MPPs) in an impedance tube is investigated using the transfer matrix method under the plane wave condition. The number of MPPs can be arbitrary, and each MPP may or may not have a perforation. For numerical examples, the STLs of single, double and triple MPPs are computed and the accuracy of the proposed

There are many methods capable of establishing the diagnosis of machinery. The vast majority make use of different condition indicators, extracting information from the vibration signals obtained in the frame. During this work, in addition to using traditional techniques, it was analysed the validity of psychoacoustic metrics as a tool for detecting mechanical failures. Although these parameters were

Recently, progressive learning has shown its capacity to improve speech quality and speech intelligibility when it is combined with deep neural network (DNN) and long short-term memory (LSTM) based monaural speech enhancement algorithms, especially in low signal-to-noise ratio (SNR) conditions. Nevertheless, due to a large number of parameters and high computational complexity, it is hard to implement

Acoustic maps are, generally, calculated according to noise directives that evaluate the noise exposure levels of a population at a reference height of 4 m to provide values that correspond to the first floors of buildings. However, in large cities, the requirements for high-density housing, such as high-rise apartment buildings, make this evaluation incomplete. In this paper, we study noise propagation

Porous materials with high flow-resistivity could provide significant sound absorption. However, the pressure drop across such materials may be unacceptable for applications involving mean flow, such as in heat sinks. The goal of this study is to design a foam macro-structure that minimizes pressure drop while retaining optimal acoustic performance. Corrugated macro-geometries have been studied previously