Showing papers in "Applied Acoustics in 2019"

TL;DR: A new statistical feature selection method is proposed based on the changes in emotions on acoustic features that provides a significant reduction in the number of features, as well as increasing the classification success.

TL;DR: In this article, a composite acoustic black hole (ABH) beam structure with low-frequency flexural wave attenuation properties was proposed. But the composite beam structure does not reveal the necessary low local stiffness or high stress concentration, and vibration modes indicate that flexural attenuation still depends on the ABH.

TL;DR: In this paper, the authors provide an overview of the design and performance of the new aero-acoustic wind tunnel facility at the University of Bristol, which comprises a large acoustic chamber, anechoic down to 160 Hz, and a temperature controlled closed-circuit wind tunnel with an open test section.

TL;DR: Dilated CNN, being introduced to ESC problem, achieves better results than that of CNN with max-pooling and other state-of-the-art approaches, and the effect of different dilation rate and the number of layers of dilated convolution to the experimental results is explored.

TL;DR: In this paper, a simplified model to evaluate the acoustic performance of hemp fibrous materials as a function of their density is proposed, in order to provide a practical tool to investigate and compare different solutions.

TL;DR: In this paper, a finite element model of the periodically distributed voids and hard inclusions in the host rubber medium is presented, where different combinations of the layers have markedly different impacts on the acoustic performance, whereby the physical mechanisms governing sound absorption are strongly dependent on the Fabry-Perot and dipole resonances associated with the presence of the inclusions.

TL;DR: In this paper, a complete set of static and fatigue loading data on thermoplastic composites based on flax fiber was provided, where static tensile tests were carried out to identify the composite mechanical properties and the damage and rupture mechanisms that occur during loading and cyclic tensile test were realized to investigate macroscopic damage.

TL;DR: It infers that, in real-time performance monitoring of an engine, the STFT technique is more efficient for fault diagnosis of fuel injection nozzles and knock detection.

TL;DR: A deep learning based underwater acoustic (UWA) orthogonal frequency-division multiplexing (OFDM) communication system interpreted as a deep neural network (DNN) can recover the transmitted symbols directly after sufficient training.

TL;DR: In this study, Deeper Long Short Term Memory (LSTM) Networks structure was used for the prediction of gender from an audio data set and was successful at predicting gender with 98.4% success rate.

TL;DR: In this article, the effect of graphene oxide loading on sound-absorbing properties of open cell polyurethane foam (PU) was investigated by a step-by-step vacuum assisted process.

TL;DR: In this article, a multilayer microperforated panel (MPP) absorber with a high sound absorption coefficient and broadband absorption at low frequencies is presented. But, the results indicate that the proposed multi-layer MPP absorber provides a good alternative for sound absorption applications.

TL;DR: The classification results demonstrate that the proposed AW-CNN approach has the capability to effectively and successfully divide sonar images into their relevant seabed classes, which is beneficial to finding mines and shoals and detecting the integrated degree of the dam bottom.

TL;DR: The aim of this work is to determine the annoyance of different electric vehicle sounds for a constant speed, single car pass-by situation and the best-performing models were compared with linear regression models based on psychoacoustic parameter.

TL;DR: In this article, the authors evaluate the sound absorption coefficient of three natural fibers: sisal, coconut husk and sugar cane with two empirical and one experimental method, and an inverse methodology was presented to optimize the coefficients of the Delany and Bazley model to better represent the studied fibers.

TL;DR: The results demonstrate that acoustic signals and ANFIS can effectively be utilized to diagnose the condition of the gearbox.

TL;DR: A novel method is proposed to detect and classify whistles of both killer whales and long-finned pilot whales based on deep convolutional neural networks, which can automatically learn the sound characteristics from the training data, without specifying the sound features for classification and detection, and thus shows better adaptability to complex sound signals.

TL;DR: In this article, an innovative approach was used to investigate and model acoustic ageing of some rubberized road surfaces surveyed for several years, considering the complex interacting system composed of three main elements: pavement type, traffic loads and climatic conditions.

TL;DR: In this article, the authors proposed an acoustical siphon effect in membrane-type metamaterials for low-frequency broadband absorption, whose physical mechanism is further investigated by the theoretical analysis and finite element (FE) simulation.

TL;DR: In this article, an inhomogeneous micro-perforated panel (MPP) absorber with multi-cavity depths is presented, where each area has different hole diameter, perforation ratio and a separated backed cavity depth.

TL;DR: A vowel recognition method is proposed using the proposed octopus pooling method and it is indicated that the proposed solves three problems with high success rates and low computational complexity.

TL;DR: The results show that new classifiers of the WOA algorithm indicate better performance than the other benchmark algorithms, in terms of avoidance from getting stuck at local minima, classification accuracy, and convergence speed.

TL;DR: In this paper, the acoustic properties of rigid micro-rods produced via additive manufacturing were analyzed using an impedance tube in the 500'Hz-6'Hz frequency range, and it was shown that broadband acoustic capabilities can be improved over the studied frequency range with the smallest filament possible or by reducing the lattice parameter and/or by changing the orientation of the filament from one layer to another.

TL;DR: A balloon dielectric elastomer actuator (DEA) speaker is constructed by forming a disk-shaped DEA film into a sphere using air, increasing its surface area by 3033%.

TL;DR: In this article, the nonlinear vibrations of functionally graded cantilevers are investigated and the constitutive relations are built and Hamilton's energy/work principle is used giving coupled continuous models.

TL;DR: This case study tested whether compatible results could be obtained from the first two methods, based on soundwalks and questionnaires, during the same data collection session, and showed that for this case study the two methods returned soundscape categorisations that are similar and have strong statistically significant associations.

TL;DR: This work evaluates the performance of four time-frequency representations for use with CNN and proposes the use of a cochleagram image the frequency components of which are based on the frequency selectivity property of the human cochLEa.

TL;DR: In this paper, the authors explored the creation of 3D printed sound cancelling waveguides that can be customised for selected frequencies as a function of geometry, and the potential for attenuation in these waveguide is characterised through experimentally measured acoustic-absorption ( α ) and transmission loss (TL).

TL;DR: Through theoretical modeling, parameter optimization, analog simulation, and experimental validation, an effective method for development of the desired sound absorber was proposed, which will be propitious to promote the applications of the multilayer microperforated panel products in the field of noise reduction.

TL;DR: In this article, the authors investigated the vibration and sound radiation of porous functionally graded material (FGM) plates with temperature gradient along the thickness, and the effects of key parameters including the boundary condition, volume fraction index, thermal environment, temperature dependence of material properties and porosity volume fraction on the structural and acoustic responses of the FGM plate are discussed in detail.