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Frequency-difference source localization (FDSL) is a relatively new method for locating sources emitting acoustic or electromagnetic waves from recorded data. Estimates of location are produced by matching a nonlinear function of the received data with the same nonlinear function of modeled data. This so-called matched-field approach depends on the accuracy of the modeled field. FDSL exhibits less sensitivity to model errors in some cases of interest. Fluctuations of the speed of sound in the ocean are affected by a wide variety of phenomena and internal gravity waves is one where their spectrum is usually well known. There is no analytical theory for predicting how these fluctuations of sound speed affect the accuracy of FDSL, leaving a numerical evaluation as the alternative for the focus of this paper. Experimental application of FDSL was previously made for an acoustic source of 100 Hz bandwidth surrounding 250 Hz for a 129 km section in the Philippine Sea with data recorded on a long vertical array [Geroski and Dowling, Long-range frequency-difference source localization in the Philippine Sea, J. Acoust. Soc. Am. 146 (2019) 4727–4739.]. The role of internal waves is quantified with a realistic FDSL simulation using models based on the parabolic and ray approximations of the linear acoustic wave equation. The modeled vertical variation of FDSL error is similar to observed while the modeled horizontal error is too small. The complicated software model is automatic but is computationally intensive, with our version needing about 1.5 mo to compute on a PC with 16 cpu cores. [ABSTRACT FROM AUTHOR]

Underwater communication is one of the most important and difficult challenges facing researchers due to the high attenuation of the signal, communication with the surface because of the harsh medium of water, and data transmission performance degradation as a result of various effects. Underwater acoustic communication (UWA) has a low data rate, which describes the disadvantage of this type of communication. In addition, it has a low bandwidth range and high latency but has a long transmission range as an advantage. Multicarrier wireless transmission systems increase the data rate by sending the data using more than one carrier. We proposed a noncoherent orthogonal frequency division multiplexing (OFDM) method to increase the data rate in UWA communication systems. In addition, doubling the data rate in the OFDM using Subcarrier Power Modulation (OFDM-SPM) system can save half of the bandwidth. The MATLAB simulation program was used to implement the system in the underwater acoustic environment to increase its throughput. The proposed design uses Differential Phase Shift Keying (DPSK) with power control, and the data stream is transmitted through two-dimensional modulation schemes, the DPSK, and the power level of each subcarrier in the OFDM system with cyclic prefix (CP). The underwater channel was designed using a Rician fading multipath with a spreading loss formula as a function of distance and frequency. We designed an equalizer at the receiver side to recover the original signal as a function of three parameters which are: the channel effect as a rate between transmitting and receiving symbols, the Rician channel response, and the UWA spreading loss. OFDM-Subcarrier Power Modulation (OFDM-SPM) using the proposed equalizer performed better than the theoretical OFDM-SPM in the Rayleigh channel. The designed equalizer increased the performance of the OFDM-SPM system by 25% which helped to enhance the system's throughput and doubled the data rate compared with the OFDM system, doubling the data rate using OFDM-SPM had been validated in laboratory experiments in the Time domain. [ABSTRACT FROM AUTHOR]

The emotional impact of sound depends on its characteristics. Given that such characteristics can be modified when the sound is played in a room, it is crucial to examine how the acoustic characteristic of a room can impact the emotional experience. Researchers have investigated the links between the acoustic parameters of concert halls and the emotional impact; however, the applicability of such links to other building types, such as worship spaces, needs to be studied. In a previous study, the author analyzed the emotional response to the acoustic environments of worship spaces using self-report and physiological indicators. This paper builds on the previous work by analyzing the acoustic parameters of the buildings from the previous study and establishing links between such parameters and the emotional response indicators. It also analyzes the frequency domain to study the role of the interaction between the room and sound source in enhancing the emotional experience and introduces resonance quality (Q) and resonance width (Δf) as important parameters to consider in room acoustics. The results showed the significance of considering frequencies < 1000 Hz in analyzing the acoustics of the studied worship spaces and demonstrated that amplifying the dominant frequency range of the sound source was linked to enhancing the emotional experience. [ABSTRACT FROM AUTHOR]

Underwater acoustic sensor networks have a wide range of applications in both civil and military fields, but the complex and changing underwater environment makes them vulnerable to multiple security threats. Trust mechanisms are effective ways to enhance network security and reliability. In order to improve the accuracy of trust evaluation and the detection rate of abnormal nodes, this paper proposes an adaptive trust evaluation model based on fuzzy logic. This model adopts a variable weight fuzzy comprehensive evaluation algorithm to dynamically adjust the weights of three direct trust indicators to ensure the accuracy of direct trust evaluation. Then, it uses fuzzy closeness to eliminate unreliable recommendation trust and adjusts the weight of recommendation trust through deviation to improve the accuracy of indirect trust. The simulation results show that the model can effectively improve the accuracy of trust evaluation and the detection rate of abnormal nodes. Especially when the link quality is unstable, the success rate of detecting abnormal nodes in this model is improved by more than 10% compared with the existing trust model. [ABSTRACT FROM AUTHOR]

A key requirement for product design is the ability to capture the physical features of structures quickly and efficiently. One way to achieve this purpose is to use machine learning to support topology optimization. However, due to the diversity of application requirements in product updates, the machine learning-based optimization model needs to be frequently rebuilt by collecting large amounts of data. In this work, Moving Morphable Component approach is combined with Deep Neural Network to achieve the quick topology optimization design of acoustic devices. A deep transfer learning approach to the predictive model is also developed for the model to be adapted to different design conditions. Thus, using the proposed approach, not only the originally designed acoustic structure can be quickly optimized, but also the serialized structures evolved from the source model can be easily obtained. Numerical examples illustrate the effectiveness and advantages of the proposed method. [ABSTRACT FROM AUTHOR]

We present a massively parallel and scalable nodal discontinuous Galerkin finite element method (DGFEM) solver for the time-domain linearized acoustic wave equations. The solver is implemented using the libParanumal finite element framework with extensions to handle curvilinear geometries and frequency dependent boundary conditions of relevance in practical room acoustics. The implementation is benchmarked on heterogeneous multi-device many-core computing architectures, and high performance and scalability are demonstrated for a problem that is considered expensive to solve in practical applications. In a benchmark study, scaling tests show that multi-GPU support gives the ability to simulate large rooms, over a broad frequency range, with realistic boundary conditions, both in terms of computing time and memory requirements. Furthermore, numerical simulations on two non-trivial geometries are presented, a star-shaped room with a dome and an auditorium. Overall, this shows the viability of using a multi-device accelerated DGFEM solver to enable realistic large-scale wave-based room acoustics simulations. [ABSTRACT FROM AUTHOR]

The aim of this paper is to discuss the effect of the sensor on the acoustic emission (AE) signature and to develop a methodology to reduce the sensor effect. Pencil leads are broken on PMMA plates at different source–sensor distances, and the resulting waves are detected with different sensors. Several transducers, commonly used for acoustic emission measurements, are compared with regard to their ability to reproduce the characteristic shapes of plate waves. Their consequences for AE descriptors are discussed. Their different responses show why similar test specimens and test conditions can yield disparate results. This sensor effect will furthermore make the classification of different AE sources more difficult. In this context, a specific procedure is proposed to reduce the sensor effect and to propose an efficient selection of descriptors for data merging. Principal Component Analysis has demonstrated that using the Z-score normalized descriptor data in conjunction with the Krustal–Wallis test and identifying the outliers can help reduce the sensor effect. This procedure leads to the selection of a common descriptor set with the same distribution for all sensors. These descriptors can be merged to create a library. This result opens up new outlooks for the generalization of acoustic emission signature libraries. This aspect is a key point for the development of a database for machine learning. [ABSTRACT FROM AUTHOR]

Shallow water passive source localization is an essential problem in underwater detection and localization. Traditional matched-field processing (MFP) methods are sensitive to environment mismatches. Many neural network localization methods still have room for improvement in accuracy if they are further adjusted to underwater acoustic characteristics. To address these problems, we propose a deep learning localization method via improved input features and network structure, which can effectively estimate the depth and the closest point of approach (CPA) range of the acoustic source. Firstly, we put forward a feature preprocessing scheme to enhance the localization accuracy and robustness. Secondly, we design a deep learning network structure to improve the localization accuracy further. Finally, we propose a method of visualizing the network to optimize the estimated localization results. Simulations show that the accuracy of the proposed method is better than other compared features and network structures, and the robustness is significantly better than that of the MFP methods. Experimental results further prove the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Open science practices have led to an increase in available speech datasets for researchers interested in acoustic analysis. Accurate evaluation of these databases frequently requires manual or semi-automated analysis. The time-intensive nature of these analyses makes them ideally suited for research assistants in laboratories focused on speech and voice production. However, the completion of high-quality, consistent, and reliable analyses requires clear rules and guidelines for all research assistants to follow. This tutorial will provide information on training and mentoring research assistants to complete these analyses, covering areas including RA training, ongoing data analysis monitoring, and documentation needed for reliable and re-creatable findings. [ABSTRACT FROM AUTHOR]

In the stress-energy tensor formalism, the symmetry between absorption and scattering coefficients, as proven by measurements combined with simulations, is counterintuitive. By introducing the wall admittance, we show that the scattering coefficient is partly created by the real part of the wall admittance combined with the active intensity, that is, is partly due to absorption. However, for curved surfaces or finite source distances, it also depends on the imaginary part of the wall admittance in combination with the reactive intensity, which confers its genuine scattering properties inversely proportional to the distances to the sources. Thus, for plane waves impinging on plane boundaries, or purely real admittances, scattering reduces to absorption. [ABSTRACT FROM AUTHOR]

The topological simulation of acoustic waves has induced unconventional propagation characteristics, thereby offering extensive application potential in the field of acoustics. In this paper, we propose a machine learning-assisted method for the inverse design of acoustic wave topological edge states and demonstrate its practical applicability. Leveraging the predictions from a trained artificial neural network algorithm, the design of wide-bandwidth topological insulators is achieved, with simulation results indicating an approximately 2.8-fold enlargement of the single-cell topological bandgap. Further investigation into their wide-bandwidth topological transport properties is conducted. Additionally, two distinct functional acoustic routing devices are devised. Superior performance of the wide-bandwidth acoustic topological devices has been verified through simulation experiments. This approach provides an efficient and viable avenue for the design and optimization of acoustic devices, with the potential to enhance the management and control efficiency of acoustic signal propagation. [ABSTRACT FROM AUTHOR]

Architects prioritize designing different buildings to maximize the utilization of natural resources such as natural lighting, natural ventilation, and renewable energy. However, some individuals overlook the focus on architectural acoustics, which deals with controlling sound transmission from the outside to the inside or improving sound distribution within spaces, and the negative impact that improper design can have on human health. According to The World Health Organization (WHO) last updated its guidelines on environmental noise in 2018. These guidelines provide recommendations and standards for addressing the impact of noise on human health and well-being. Affirming that noise has negative effects and serious health consequences, including hearing loss, cardiovascular diseases, and a decline in physical and mental performance. Therefore, the research addresses a scientific methodology that assists architects in designing spaces that achieve sound comfort, with a particular focus on educational spaces, including a case study on lecture halls in universities... [ABSTRACT FROM AUTHOR]

What sounds and noises does a future building make? How do architectural acousticians listen to a building in the making? How do you measure something that is not yet there? What is the epistemological status of approximations? Following the listening practices of acousticians as they measure a future experience of sound through a mock-up and of noise through an incomplete simulation, this article explores the challenge of fixing sound and noise as elusive objects of knowledge. Based on an ethnography of a building project, we see how architectural acousticians rely on what they call "approximations," both the inscriptions and inscriptive work used to give traces of reality to future lived experiences of sound and noise that they hope "would be" there. Bringing together sound studies, ethnographies of architectural practice and science and technology studies accounts of inscription practices, the article argues for attention to be placed on the ephemera of knowledge and design practices, which allows analytic focus to remain upstream between the possible and the actual. Situated within the practices of the acousticians, we can witness some of the ways that sound and noise take shape within a building project, grosso modo. [ABSTRACT FROM AUTHOR]

The article titled "It's Not Just about Technology!': Creativity as a Driving Force for Nurturing the Development of Skills for Digital Performance" emphasizes the significance of creativity in developing skills for digital performance. The authors argue that creativity is essential alongside technological proficiency in the digital performance field. The article provides insights and perspectives from researchers based in Brazil, Ireland, Italy, and Denmark. It encourages individuals to embrace experimentation, collaboration, and the use of technology in order to break away from traditional music theory and genres. The article also acknowledges the political implications and challenges associated with these new frameworks and emphasizes the importance of knowledge sharing and dialogical practices. [Extracted from the article]

This work presents a data-driven optimization technique for the optimization of the flame response within a low-order acoustic network model. The methodology exploits the Nyquist criterion to compute a measure of thermoacoustic robustness at targeted frequencies, which serves as an objective value for the optimized system. The method is demonstrated using a simple Rijke tube model coupled with a G -equation solver to model flame dynamics. The approach is shown to efficiently increase the stability margin of the system by modifying the flame transfer function. The methodology is applied to two examples, based on which possible scenarios are discussed and the potential and limitations associated with the practical implementation of the method are analyzed. [ABSTRACT FROM AUTHOR]

The image source (IS) method is a commonly used geometrical acoustics simulation technique in room and virtual acoustics. In particular, it has been used in the analysis of room reverberation under different choices of geometry and wall conditions. Under a simple rectangular parallelepipedal geometry, reverberation time is known to be dependent on the direction of arrival of reflections relative to the room axes. In this article, a closed-form expression for the directional energy decay and reverberation time is derived, which is valid in the late response, and may be used in the case of either angle-independent or angle-dependent reflection. The expression reduces to an easily evaluated formula in the case of an omnidirectional energy decay curve (EDC). Various numerical results are presented, including the validation of the closed-form expression against EDCs and late reverberation times drawn directly from the IS method. [ABSTRACT FROM AUTHOR]

A method is presented for estimating and reconstructing the sound field within a room using physics-informed neural networks. By incorporating a limited set of experimental room impulse responses as training data, this approach combines neural network processing capabilities with the underlying physics of sound propagation, as articulated by the wave equation. The network's ability to estimate particle velocity and intensity, in addition to sound pressure, demonstrates its capacity to represent the flow of acoustic energy and completely characterise the sound field with only a few measurements. Additionally, an investigation into the potential of this network as a tool for improving acoustic simulations is conducted. This is due to its proficiency in offering grid-free sound field mappings with minimal inference time. Furthermore, a study is carried out which encompasses comparative analyses against current approaches for sound field reconstruction. Specifically, the proposed approach is evaluated against both data-driven techniques and elementary wave-based regression methods. The results demonstrate that the physics-informed neural network stands out when reconstructing the early part of the room impulse response, while simultaneously allowing for complete sound field characterisation in the time domain. [ABSTRACT FROM AUTHOR]

Singing voice separation on robots faces the problem of interpreting ambiguous auditory signals. The acoustic signal, which the humanoid robot perceives through its onboard microphones, is a mixture of singing voice, music, and noise, with distortion, attenuation, and reverberation. In this paper, we used the 3D Inception-ResUNet structure in the U-shaped encoding and decoding network to improve the utilization of the spatial and spectral information of the spectrogram. Multiobjectives were used to train the model: magnitude consistency loss, phase consistency loss, and magnitude correlation consistency loss. We recorded the singing voice and accompaniment derived from the MIR-1K dataset with NAO robots and synthesized the 10-channel dataset for training the model. The experimental results show that the proposed model trained by multiple objectives reaches an average NSDR of 11.55 dB on the test dataset, which outperforms the comparison model. [ABSTRACT FROM AUTHOR]

A kind of acoustic metasurface (AMS) with multiple response frequency bands based on the replace method was proposed, which composed of six units, each containing three split hollow cubics (SHCs) (denoted as the AAA type of AMS). The simulation results demonstrated that the presented AMS can achieve the flexible modulation of the reflected wave direction. The AAA type of AMS had one response band, the AAC type of AMS had two different response bands, and the ABC type of AMS had three different response bands. Furthermore, the response bandwidth of the ABC type of AMS declined the most in the middle-frequency band, followed in the low-frequency band, and the least in the high-frequency band, when compared to the corresponding AAA type of AMS with single bandwidth. In addition, it was worth noting that the ABC type of AMS not only enlarged the manipulation direction of reflected acoustic wave, but also improved the effects of the wavefront distribution at the same frequency. This multiple band AMS will be beneficial for the application of architectural acoustics, and acoustic absorption and noise reduction. [ABSTRACT FROM AUTHOR]

In recent years, lead-free piezoelectric ceramic devices have been extensively researched and applied in the high-frequency range, specifically above 20 kHz, for airborne acoustics applications. However, few applications have been reported on low-frequency underwater acoustic transducers, which are crucial in the fields of underwater acoustic communication, ocean resource development, etc., because this imposes more stringent requirements for lead-free piezoelectric ceramics in terms of size, mechanical coupling coefficient, piezoelectric coefficients, and temperature stability. This paper explores the application of high-performance potassium sodium niobate based lead-free piezoelectric ceramics in a low-frequency directional wideband transducer. It covers design, fabrication, and performance testing of the transducer. The transducer measures Φ236 × 83 mm2 and weighs 4.45 kg, which achieves wideband emission (3500–8200 Hz) and directional sound emission with a front-to-back sound pressure ratio exceeding 6 dB across a significant frequency range. Both the theoretical analysis and the experimental results confirm the competitiveness application of the lead-free piezoelectric ceramics in the field of low-frequency underwater acoustic transducers applications. [ABSTRACT FROM AUTHOR]

• Collaborative work between sciences of acoustics and anthropology allows to decipher the reported perceptions of the acoustics of Notre-Dame de Paris. • Although the acoustics of Notre-Dame de Paris before the fire were remarkable in several aspects, musicians report than they were dificult to "tame" in the context of modern musical and liturgical uses. • Musical clarity suffered from large distances between the singers and the assembly as well as from architectural particularities of Notre-Dame de Paris. • Due to poor clarity in the nave, various sound system configurations were used to assist musical, vocal, and speech productions. This interdisciplinary study brings together acousticians and anthropologists to examine the memory of the acoustics of Notre-Dame de Paris before the fire of April 2019, using a qualitative approach to collect the testimonies of 18 people involved in the sound usages of the cathedral. Testimonies were analyzed in light of research conducted in the anthropology of the senses, sensory perception, memory, and cultural heritage. Analysis highlights an apparent contradiction between the remarkable acoustics of the monument before the fire and the impression of musicians. These musicians reported a struggle to tame the cathedral's sound space, to hear each other well enough to craft their performances and to reach an acceptable level of clarity in their musical practice. These phenomena are examined with acoustic measurements and numerical simulations using a calibrated geometrical acoustics model of the cathedral before the fire, which allows for an objective exploration of the acoustic characteristics of Notre-Dame. This analysis concludes that the well-known reverberation of Notre-Dame, as well as the acoustic barrier of the transept and the poor acoustic return on the podium (the usual place for concert performers) negatively impact singers' comfort. This highlights the tension between the original architectural design of the cathedral and its modern religious and cultural usages. However, the regular occupants have developed a deep familiarity with these constraints during their ritual and musical practices, adjusting to the acoustics in a unique way. Such a tradition of adaptation must be considered as a part of cultural practice, not to be overlooked during the reconstruction. [ABSTRACT FROM AUTHOR]

Sound zone methods aim to control the sound field produced by an array of loudspeakers to render a given audio content in specific areas while making it almost inaudible in others. At low frequencies, control filters are based on information of the electro-acoustical path between loudspeakers and listening areas, contained in the room impulse responses (RIRs). This information can be acquired wirelessly through ubiquitous networks of microphones. In that case and for real-time applications in general, short acquisition and processing times are critical. In addition, limiting the amount of data that should be retrieved and processed can also reduce computational demands. Furthermore, such a framework would enable fast adaptation of control filters in changing acoustic environments. This work explores reducing the amount of time and information required to compute control filters when rendering and updating low-frequency sound zones. Using real RIR measurements, it is demonstrated that in some standard acoustic rooms, acquisition times on the order of a few hundred milliseconds are sufficient for accurately rendering sound zones. Moreover, an additional amount of information can be removed from the acquired RIRs without degrading the performance. [ABSTRACT FROM AUTHOR]

The image source method (ISM) is often used to simulate room acoustics due to its ease of use and computational efficiency. The standard ISM is limited to simulations of room impulse responses between point sources and omnidirectional receivers. In this work, the ISM is extended using spherical harmonic directivity coefficients to include acoustic diffraction effects. These effects occur in practice when transducers are mounted on audio devices of finite spatial extent, e.g., modern smart speakers with loudspeakers and microphones. The proposed method is verified using finite element simulations of various loudspeaker and microphone configurations in a shoebox-shaped room. It is shown that the accuracy of the proposed method is related to the sizes, shapes, number, and positions of the devices inside a room. A simplified version of the proposed method, which can significantly reduce computational effort, is also presented. The proposed method and its simplified version can simulate room transfer functions more accurately than currently available image source methods and can aid the development and evaluation of speech and acoustic signal processing algorithms, including speech enhancement, acoustic scene analysis, and acoustic parameter estimation. [ABSTRACT FROM AUTHOR]

Impulse responses (IRs) estimation of multi-input acoustic systems is a prerequisite for many audio applications. In this paper, an adaptive identification problem based on the Autostep algorithm is extended to the simultaneous estimation of room IRs for multiple input single output linear time invariant systems without any a priori information. To do so, the proposed algorithm is initially evaluated in a simulated room with several sound sources active at the same time. Finally, an experimental validation is proposed for the cases of a semi-anechoic chamber and an arbitrary room. Special attention is dedicated to the algorithm convergence behavior, considering different meta parameters settings. Results are eventually compared with the other normalized version of the least mean square algorithm. [ABSTRACT FROM AUTHOR]

One of the most common ways to assess the activity of acoustic emission (AE) sources and their hazard under mechanical loading of materials and structures is to use the local-dynamic criterion. To verify the latter, specimens of various materials, namely fiberglass, corundum refractory, and steel, were tested under static loading during three-point bending. A special software AE-Criterion was developed to determine the AE parameters, including the current parameters of source activity, based on the local dynamic criterion using both the force factor and the time since the beginning of the test. Taking into account the multiplicity and stochastic nature of AE events during the loading of materials, it is proposed to determine the average values of MS, MT, and the values of the indices IAS and IAT of the activity degree of AE sources when applying the force parameter and time, respectively. The analysis of the data obtained during the bending tests of the above-mentioned specimens and, accordingly, the calculation of the parameters of source activity showed that the value of the index IAS, when using the force factor, satisfactorily reflects the deformation and fracture processes of these materials. The study's results indicate the suitability of the local dynamic criterion for diagnosing the deformation and fracture processes of the above materials. [ABSTRACT FROM AUTHOR]

Central-planned halls are highly widespread in the historical architectures of the Western world, such as rotundae, Christian baptisteries, and Roman tombs. In such halls, whispering galleries, flutter echoes, and sound focusing are the acoustic phenomena mainly investigated by scholars. Instead, modal behaviour and free path distribution are generally less treated in literature. The present study explores the modal density at low frequencies and the relationship with the most recurrent free path lengths in three historical nearly circular spaces, here assessed as case studies. Acoustic measurements allowed the collection of objective experimental data, i.e., room impulse responses and the resulting room acoustics criteria. Wave-based numerical models allowed for the investigation of the eigenfrequencies distribution, while the free paths trend has been experienced through ray-based models. The main outcomes of both analyses show the prominence of the circular modes, rather than the diametral and the elevation ones. Moreover, the mean free path calculated using ray-tracing proves to be higher than the theoretical value commonly assumed for any kind of shape. The consequent longer reverberations compared to halls with other shapes and the same volume justify the significant support historically provided to sound signals by circular halls. [ABSTRACT FROM AUTHOR]

Numerous studies highlight the analysis and modeling of the characteristics of the musical timbre of violins, obtained on the basis of the acoustic perception of the experienced subjects, the acoustic quality of the violins being interpreted on the basis of the statistical analysis of the psycho-acoustic impressions. Also, there are studies on the structural behavior of the violin to determine signature modes. However, the analysis of the radiated frequency response in three overlapping regions, as described in the literature, have been less studied. In this sense, the paper presents the study of the behavior of a historical violin, on the entire audio range, examining the frequency response function. The acoustic signal is produced by the excitation of the strings by the violinist, and the recording of the acoustic signals was made both in a concert hall and in an anechoic chamber. The results in the form of acoustic spectrograms, frequency spectrum, magnitude, and power spectrum density for each receiver were analyzed comparatively between the two acoustic spaces, the sounds emitted by the violins are amplified or dampened. [ABSTRACT FROM AUTHOR]

In this study, we introduce a physical model of a three-dimensional (3D) guided wave sensor called 3D-CMUT, which is based on capacitive micro-machined ultrasonic transducers (CMUTs). This 3D-CMUT sensor is designed to effectively and simultaneously obtain 3D vibration information about ultrasonic guided waves in the out-of-plane (z-direction) and in-plane (x and y-directions). The basic unit of the 3D-CMUT is much smaller than the wavelength of the guided waves and consists of two orthogonal comb-like CMUT cells and one piston-type CMUT cell. These cells are used to sense displacement signals in the x, y, and z-directions. To ensure proper functioning of the 3D-CMUT unit, the resonant frequencies of the three composed cells are set to be identical by adjusting the microstructural parameters appropriately. Moreover, the same sensitivity in the x, y, and z-directions is theoretically achieved by tuning the amplification parameters in the external circuit. We establish a transient analysis model of the 3D-CMUT using COMSOL finite element simulation software to confirm its ability to sense multimode ultrasonic guided waves, including A0, S0, and SH0 modes. Additionally, we simulate the ball drop impact acoustic emission signal on a plate to demonstrate that the 3D-CMUT can not only utilize in-plane information for positioning but also out-of-plane information. The proposed 3D-CMUT holds significant potential for applications in the field of structural health monitoring (SHM). [ABSTRACT FROM AUTHOR]

Objective: Examine the extent to which increasing information integration across displays in a simulated submarine command and control room can reduce operator workload, improve operator situation awareness, and improve team performance. Background: In control rooms, the volume and number of sources of information are increasing, with the potential to overwhelm operator cognitive capacity. It is proposed that by distributing information to maximize relevance to each operator role (increasing information integration), it is possible to not only reduce operator workload but also improve situation awareness and team performance. Method: Sixteen teams of six novice participants were trained to work together to combine data from multiple sensor displays to build a tactical picture of surrounding contacts at sea. The extent that data from one display were available to operators at other displays was manipulated (information integration) between teams. Team performance was assessed as the accuracy of the generated tactical picture. Results: Teams built a more accurate tactical picture, and individual team members had better situation awareness and lower workload, when provided with high compared with low information integration. Conclusion: A human-centered design approach to integrating information in command and control settings can result in lower workload, and enhanced situation awareness and team performance. Application: The design of modern command and control rooms, in which operators must fuse increasing volumes of complex data from displays, may benefit from higher information integration based on a human-centered design philosophy, and a fundamental understanding of the cognitive work that is carried out by operators. [ABSTRACT FROM AUTHOR]

Micro-perforated panel sound absorbers are widely used in noise control applications in the fields of architectural acoustics and transport acoustics. Combining micro-perforated panels with other resonant or sound absorbing systems may broaden the frequency range in which they absorb sound while ensuring that large sound absorption values are reached. In this work, a hybrid sound absorber that combines a micro-perforated panel and a coiled quarter wavelength tube is proposed. Series and parallel configurations of these two systems are studied from analytical, numerical, and experimental point of views. A comparison of two three-dimensional (3D) printing techniques for the production of samples highlights the main challenges for the practical implementation of the proposed design. The advantages and limitations of series and parallel arrangements are discussed and while the parallel configuration is more complex to setup in practice, it provides an improved sound-absorbing performance compared with the series configuration. Finally, the reproducibility of the hybrid absorber in parallel configuration is confirmed by testing samples that were produced with two different 3D printers and in two different laboratories. [ABSTRACT FROM AUTHOR]

The article discusses the LXIX Open Seminar on Acoustics OSA2023 was held in Karpacz, Poland, from September 25 to 29, 2023. It reports that the event was organized by the Polish Acoustical Society's Wroclaw Branch and included two companion events: the Signal Processing Symposium SPSympo23 and the 5th Polish-German Structured Conference on Acoustics PGSCA2023. It mentions that experts from Poland as well as abroad took part, delivering papers and making plenary speeches.

Digital electronics is a technological cornerstone in this modern society that has covered the increasing demand for computing power during the last decades thanks to a periodic doubling of transistor density in integrated circuits. Currently, such scaling law is reaching its fundamental limit, leading to the emergence of a large gamut of applications that cannot be supported by digital electronics, specifically, those that involve real‐time multi‐data processing, e.g., medical diagnostic imaging, robotic control, and autonomous driving, among others. In this scenario, an analog computing approach implemented in a real‐time reconfigurable nonelectronic hardware such as programmable integrated photonics (PIP) can be more efficient than digital electronics to perform these emerging applications. However, actual analog computing models such as quantum and neuromorphic computation were not conceived to extract the unique benefits of PIP (and integrated photonics in general). Here, the foundations of a new computation theory are presented, termed Analog Programmable‐Photonic Computation (APC), explicitly designed to unleash the full potential of PIP technology. Interestingly, APC enables overcoming basic theoretical and technological limitations of existing computational models and can be implemented in other technologies (e.g., in electronics, acoustics or using metamaterials), consequently exhibiting the potential to spark a ground‐breaking impact on the information society. [ABSTRACT FROM AUTHOR]

The article focuses on the Special Issue on Inverse Problems in Acoustics, which highlights the increasing attention on solving problems related to sound source localization and sound field reconstruction through indirect measurements. Topics covered include techniques for capturing sound field information, inversion algorithms, and addressing challenges such as ill-posedness and instability.