Hasil untuk "Acoustics in engineering. Acoustical engineering"

Ruetz Marcel, Antretter Thomas, Gänser Hans-Peter

This short communication presents a new combined numerical and signal processing based analysis of the influence of stress gradients on Rayleigh wave propagation. The method uses finite element simulations based on the hyperelastic Murnaghan model, to caputure the acoustoelastic effect, and an adapted coda Wave Interferometry (CWI) technique to quantify time shift and stretch of Rayleigh wave signals. It is shown that the stress gradient alters both wave velocity and wave shape. While tensile stress reduces wave velocity, a stress gradient can counteract this effect and even enhance the propagation velocity. The combined evaluation of time shift and stretch allows an effective description of the influence of both surface stress and stress gradient on the wave propagation.

Stürenburg Lara, Braren Hark, Aspöck Lukas et al.

Air-to-water heat pumps are increasingly replacing traditional heating systems because of their environmental and energy benefits. However, noise emitted by their fans and compressors can cause complaints, even when regulatory limits are met. In this study, two listening experiments were conducted to examine heat pump noise by quantifying it as level penalties for equivalent loudness and preference. The study investigates how the preference-equivalent level differs from the loudness-equivalent level compared to a reference stimulus, and which psychoacoustic parameters best model the resulting level adjustments. Recordings from two heat pumps were auralised into a suburban residential setting and adjusted to an initial level of 60 dB(A). A two-alternative forced-choice (2-AFC) method with a 1-up-1-down rule is used to determine the point of subjective equality (PSE) for loudness and preference. Statistical analyses show significant differences between loudness-equivalent and preference-equivalent levels for eight of twelve stimuli. The median values further indicate that achieving equal preference relative to the reference generally requires lower sound pressure levels than achieving equal loudness, with the magnitude of this level offset varying across stimuli. Combining the results with psychoacoustic parameter analyses, two models based on linear regression were developed. This linear approach was chosen to ensure straightforward interpretability and robustness for the given stimulus set. Perceived loudness can be modelled by the psychoacoustic parameter loudness, while preference is best modelled by a linear combination of sharpness and roughness. These findings emphasise the need for perceptual metrics beyond A-weighted sound pressure levels when evaluating and optimising heat pump noise.

Junwei Yu, Mufeng Yang, Yepeng Ding et al.

The proliferation of AI-powered search engines has shifted information discovery from traditional link-based retrieval to direct answer generation with selective source citation, creating new challenges for content visibility. While existing Generative Engine Optimization (GEO) approaches focus primarily on semantic content modification, the role of structural features in influencing citation behavior remains underexplored. In this paper, we propose GEO-SFE, a systematic framework for structural feature engineering in generative engine optimization. Our approach decomposes content structure into three hierarchical levels: macro-structure (document architecture), meso-structure (information chunking), and micro-structure (visual emphasis), and models their impact on citation probability across different generative engine architectures. We develop architecture-aware optimization strategies and predictive models that preserve semantic integrity while improving structural effectiveness. Experimental evaluation across six mainstream generative engines demonstrates consistent improvements in citation rate (17.3 percent) and subjective quality (18.5 percent), validating the effectiveness and generalizability of the proposed framework. This work establishes structural optimization as a foundational component of GEO, providing a data-driven methodology for enhancing content visibility in LLM-powered information ecosystems.

Antonio J. Torija, Siddhartha Krishnamurthy, R. Merino-Martínez

S. Whiteley, G. Wolfowicz, G. Wolfowicz et al.

Hybrid spin–mechanical systems provide a platform for integrating quantum registers and transducers. Efficient creation and control of such systems require a comprehensive understanding of the individual spin and mechanical components as well as their mutual interactions. Point defects in silicon carbide (SiC) offer long-lived, optically addressable spin registers in a wafer-scale material with low acoustic losses, making them natural candidates for integration with high-quality-factor mechanical resonators. Here, we show Gaussian focusing of a surface acoustic wave in SiC, characterized using a stroboscopic X-ray diffraction imaging technique, which delivers direct, strain amplitude information at nanoscale spatial resolution. Using ab initio calculations, we provide a more complete picture of spin–strain coupling for various defects in SiC with C3v symmetry. This reveals the importance of shear strain for future device engineering and enhanced spin–mechanical coupling. We demonstrate all-optical detection of acoustic paramagnetic resonance without microwave magnetic fields, relevant for sensing applications. Finally, we show mechanically driven Autler–Townes splittings and magnetically forbidden Rabi oscillations. These results offer a basis for full strain control of three-level spin systems.The authors use surface acoustic waves, focused in a Gaussian geometry, to manipulate the spin state of divacancy defects in silicon carbide via mechanical driving. They demonstrate that shear strain is important in controlling the spin transitions.

Bogey Christophe, Vincent Hugo

The influence of boundary-layer tripping on the acoustic tones generated by a jet at a Mach number of 0.9 impinging on a flat plate is investigated for two nozzle-to-plate distances. Tripping the jet boundary-layer is found not to appreciably alter the frequencies but to significantly affect the levels of the tones. These effects strongly depend on the tone number and on the nozzle-to plate distance. For a given tone, in particular, the levels can decrease or increase depending on the distance. Therefore, tripping the boundary layers of impinging jets can result to less or more noise, and cannot be considered as a reliable method to reduce noise for these jets.

Claes Leander, Koch Kevin, Friesen Olga et al.

This paper proposes an approach to identify a full set of piezoelectric material parameters by solving an inverse problem supported by data-driven methods, in particular neural networks. The accurate, quantitative description of piezoelectric material behaviour is challenging due to the large number of parameters, the complexity of the interacting physical quantities, and inability to infer material parameter values directly from certain measurements. Studies have shown that a full set of material parameters can be identified by solving an inverse problem, matching the electrical impedance of samples with the output of a simulation model. The solution method of the said inverse problem is hard to regularise due to vastly different sensitivities of the impedance with respect to certain material parameters and a large parameter space. Using synthetically generated training data, a method for initial value estimation using a neural network to invert the simulation model is proposed. The initial values are refined in an intermediate optimisation step using a second neural network that mimics the simulation model. The subsequent gradient-based optimisation process converges significantly faster than previous approaches and yields a better fit to the measurement data. Changes in properties that occur when the sample is exposed to different temperatures are examined to assess the ability of the method to resolve small differences in material behaviour.

Zotter Franz, Riedel Stefan, Gölles Lukas et al.

In an ideal isotropic diffuse sound field, uncorrelated plane waves arrive uniformly from all directions. Recent theoretical work has shown that uncorrelated sources arranged on a spherical surface can also be used to synthesize diffuse fields that exhibit a uniformly vanishing active sound intensity, albeit without position-independent isotropy. How the principles extend to finite-sized rectangular cuboid and discrete source layouts remains an open question. This study considers the multi-axial superellipsoid as a flexible parametric geometry for uncorrelated acoustic source distributions. By tuning its shape parameter p, the superellipsoid transitions from an ellipsoid p=2 to a rectangular cuboid p→∞, enabling a systematic analysis of active intensity using differential geometry, Gegenbauer expansion, and numerical simulations. Findings indicate that a superellipsoidal source layer of directionally uniform density requires to be driven by a non-uniform source variance, for which a generic solution is proposed. For the ellipsoid, the proposed variance is exact and emphasizes distant sources, while for the rectangular cuboid, it remains an approximation, but still effectively emphasizes sources near edges and corners. For discrete source layouts, zero active intensity can be approximately synthesized within a domain shrunk by a factor of N/(N+1) N N + 1 $\frac {N}{N+1}$ provided that (i) sources are arranged in uniform directions of a tight spherical 2N+1 design and sample the proposed variance, or (ii) a comparable number of sources with uniform variance is distributed in a minimum potential energy configuration.

Hashini Gunatilake, John Grundy, Rashina Hoda et al.

Empathy plays a crucial role in software engineering (SE), influencing collaboration, communication, and decision-making. While prior research has highlighted the importance of empathy in SE, there is limited understanding of how empathy manifests in SE practice, what motivates SE practitioners to demonstrate empathy, and the factors that influence empathy in SE work. Our study explores these aspects through 22 interviews and a large scale survey with 116 software practitioners. Our findings provide insights into the expression of empathy in SE, the drivers behind empathetic practices, SE activities where empathy is perceived as useful or not, and the other factors that influence empathy. In addition, we offer practical implications for SE practitioners and researchers, offering a deeper understanding of how to effectively integrate empathy into SE processes.

Justus Bogner, Roberto Verdecchia

From its early foundations in the 1970s, empirical software engineering (ESE) has evolved into a mature research discipline that embraces a plethora of different topics, methodologies, and industrial practices. Despite its remarkable progress, the ESE research field still needs to keep evolving, as new impediments, shortcoming, and technologies emerge. Research reproducibility, limited external validity, subjectivity of reviews, and porting research results to industrial practices are just some examples of the drivers for improvements to ESE research. Additionally, several facets of ESE research are not documented very explicitly, which makes it difficult for newcomers to pick them up. With this new regular ACM SIGSOFT SEN column (SEN-ESE), we introduce a venue for discussing meta-aspects of ESE research, ranging from general topics such as the nature and best practices for replication packages, to more nuanced themes such as statistical methods, interview transcription tools, and publishing interdisciplinary research. Our aim for the column is to be a place where we can regularly spark conversations on ESE topics that might not often be touched upon or are left implicit. Contributions to this column will be grounded in expert interviews, focus groups, surveys, and position pieces, with the goal of encouraging reflection and improvement in how we conduct, communicate, teach, and ultimately improve ESE research. Finally, we invite feedback from the ESE community on challenging, controversial, or underexplored topics, as well as suggestions for voices you would like to hear from. While we cannot promise to act on every idea, we aim to shape this column around the community interests and are grateful for all contributions.

Hashini Gunatilake, John Grundy, Rashina Hoda et al.

Empathy plays a critical role in software engineering (SE), influencing collaboration, communication, and user-centred design. Although SE research has increasingly recognised empathy as a key human aspect, there remains no validated instrument specifically designed to measure it within the unique socio-technical contexts of SE. Existing generic empathy scales, while well-established in psychology and healthcare, often rely on language, scenarios, and assumptions that are not meaningful or interpretable for software practitioners. These scales fail to account for the diverse, role-specific, and domain-bound expressions of empathy in SE, such as understanding a non-technical user's frustrations or another practitioner's technical constraints, which differ substantially from empathy in clinical or everyday contexts. To address this gap, we developed and validated two domain-specific empathy scales: EmpathiSEr-P, assessing empathy among practitioners, and EmpathiSEr-U, capturing practitioner empathy towards users. Grounded in a practitioner-informed conceptual framework, the scales encompass three dimensions of empathy: cognitive empathy, affective empathy, and empathic responses. We followed a rigorous, multi-phase methodology, including expert evaluation, cognitive interviews, and two practitioner surveys. The resulting instruments represent the first psychometrically validated empathy scales tailored to SE, offering researchers and practitioners a tool for assessing empathy and designing empathy-enhancing interventions in software teams and user interactions.

Tomasz P. Stefański, Tomasz Białaszewski, Marek Grzegorek et al.

In this paper, we propose a unified approach to acoustic and electromagnetic field theories which employs control engineering methods for their analysis and modelling. Both theories can be derived from the wave equation using factorisation and subsequently represented as a system with a feedback loop in control engineering. This allows for the formulation of properties and solutions useful for further analysis. Moreover, it provides a justification and explanation of similarities between acoustics and electromagnetism. Hopefully, our unified approach to acoustic and electromagnetic field theories carries implications for the foundational understanding of both theories as well as their practical applications.

R. Rasouli, Karina Martinez Villegas, M. Tabrizian

For more than 70 years, acoustic waves have been used to screen, diagnose, and treat patients in hundreds of medical devices. The biocompatible nature of acoustic waves, their non-invasive and contactless operation, and their compatibility with wide visualization techniques are just a few of the many features that lead to the clinical success of sound-powered devices. The development of microelectromechanical systems and fabrication technologies in the past two decades reignited the spark of acoustics in the discovery of unique microscale bio applications. Acoustofluidics, the combination of acoustic waves and fluid mechanics in the nano and micro-realm, allowed researchers to access high-resolution and controllable manipulation and sensing tools for particle separation, isolation and enrichment, patterning of cells and bioparticles, fluid handling, and point of care biosensing strategies. This versatility and attractiveness of acoustofluidics have led to the rapid expansion of platforms and methods, making it also challenging for users to select the best acoustic technology. Depending on the setup, acoustic devices can offer a diverse level of biocompatibility, throughput, versatility, and sensitivity, where each of these considerations can become the design priority based on the application. In this paper, we aim to overview the recent advancements of acoustofluidics in the multifaceted fields of regenerative medicine, therapeutic development, and diagnosis and provide researchers with the necessary information needed to choose the best-suited acoustic technology for their application. Moreover, the effect of acoustofluidic systems on phenotypic behavior of living organisms are investigated. The review starts with a brief explanation of acoustofluidic principles, the different working mechanisms, and the advantages or challenges of commonly used platforms based on the state-of-the-art design features of acoustofluidic technologies. Finally, we present an outlook of potential trends, the areas to be explored, and the challenges that need to be overcome in developing acoustofluidic platforms that can echo the clinical success of conventional ultrasound-based devices.

F. Kronowetter, M. Maeder, Chiang Kei Yan et al.

Quasi-bound states in the continuum (QBICs) coupling into the propagating spectrum manifest themselves as high-quality factor (Q) modes susceptible to perturbations. This poses a challenge in predicting stable Fano resonances for realistic applications. Besides, where and when the maximum field enhancement occurs in real acoustic devices remains elusive. In this work, we theoretically predict and experimentally demonstrate the existence of a Friedrich-Wintgen BIC in an open acoustic cavity. We provide direct evidence for a QBIC by mapping the pressure field inside the cavity using a Laser Doppler Vibrometer (LDV), which provides the missing field enhancement data. Furthermore, we design a symmetry-reduced BIC and achieve field enhancement by a factor of about three compared to the original cavity. LDV measurements are a promising technique for obtaining high-Q modes’ missing field enhancement data. The presented results facilitate the future applications of BICs in acoustics as high-intensity sound sources, filters, and sensors.

Gerken Merle, Hohmann Volker, Grimm Giso

Virtual reality with multichannel audio playback is increasingly used in hearing aid research. The purpose of this study is to compare horizontal (2D) and periphonic (3D) rendering methods in terms of localization, minimum audible angle, and perceptual ratings related to spatial quality. Higher Order Ambisonics, Vector-Base Amplitude Panning, and Nearest Speaker Selection were used, with playback through 16, 29 and 45 speakers. The results show that an improvement in vertical localization can be obtained by using periphonic rendering instead of horizontal rendering. The perceptual advantage of periphonic rendering depends on the spatial complexity of the scene; it disappears in complex acoustic environments. Scenes with low acoustic complexity, such as a single primary sound source in a room, benefit from Nearest Speaker Selection rendering. For more complex scenes with multiple sound sources, such as a symphony orchestra in a concert hall with many primary sources, or traffic on a road with moving sources, horizontal rendering methods such as 2D Higher Order Ambisonics will provide similar or better performance.

Grimm Giso

The “OVBOX” is a tool for low-delay network audio communication and generic data transmission between multiple clients. Acoustic end-to-end delays of about 30 ms can be achieved, assuming a good internet connection and a distance between clients of less than about 1500 km. For optimal spatial perception, e.g., when using multiple instruments of similar timbre, an individual 3-dimensional room acoustic simulation based on physical modelling is applied in each client. The system is optimised for headless operation using a dedicated single-board computer (Raspberry Pi 4B), but desktop clients are also available for better integration with other audio software. A client-server system allows remote configuration and automatic traversal of network address translation routers and firewalls. With the low latency that can be achieved, the “OVBOX” is used for music applications such as distributed rehearsals or concerts. Other applications include hearing research to achieve interactive speech communication with low delay transmission of head movements for real-time control of virtual reality, and transmission of other biophysical data for online analysis or central data logging. The tool is fully open source.

Chen Xiaochao, Aletta Francesco, Moshona Cleopatra Christina et al.

In recent decades, there has been a growing interest in urban soundscapes and a shift towards a user-focused approach in urban sound environments. Despite this interest, there is no comprehensive taxonomy for soundscape design available. The Catalogue of Soundscape Interventions (CSI) project aims to fill this gap by creating a tool to collect and share data on real soundscape practices, with the goal of developing a design toolkit and brief to facilitate communication between local authorities, consultants, and researchers. An online platform has been launched to gather instances of soundscape interventions. This paper proposes eight dimensions of soundscape interventions and presents a taxonomy that categorizes these interventions based on recurring strategies and goals observed in 43 practice cases collected. These dimensions include stages, contributors, scale, period of time, intervention types, public involvement, aims and purposes, and approaches. As soundscape practices increase in complexity and variety, the taxonomy can be revised and expanded. Nevertheless, the provided taxonomy serves as an orientation aid for understanding, analyzing, and designing soundscapes, leading to the development of more harmonious and contextually appropriate acoustic environments.

Hasheminejad Seyyed M., Lissek Hervé, Vesal Rahim

Impact-loaded floor structures radiate undesired sound waves into adjacent rooms, compromising the acoustic comfort. On the other hand, substantial structural vibrations caused by the impact loading offer a promising energy source for harvesting. Nevertheless, a systematic analytical or numerical investigation of simultaneous inter-floor impact sound transmission control and energy harvesting appears to be missing. Current study describes the conceptual development of a fully coupled 3D analytical model of a dual-functional double-plate floor structure optimized for hybrid regenerative control of inter-floor impact sound transmission. Leveraging multi-mode shunted piezoelectric and Electromagnetic Damper (EMD) energy transduction mechanisms, the model structure is composed of two PZT sandwich plates, which are interlinked through a Nonlinear Vibration Absorber (NVA)-based EMD. The finite Fourier cosine transform and standard normal mode approach are employed to treat the governing acousto-elastic equations. Non-dominated Sorting Genetic Algorithm II is applied to tune the system parameters along Pareto frontiers to target maximum pressure mitigation, maximum energy harvesting, or dual-objective optimization, which hires advantageous features from both configurations for an optimal trade-off between them. Simulations reveal that elasto-acoustic response suppression and energy extraction of the employed stand-alone PZT-based conversion mechanism can be remarkably improved with the adopted optimized hybrid PZT/NVA/EMD-equipped system.

Gaillard Amélie, Koehl Vincent, Gazengel Bruno

Since the late 19th century, researchers have measured and predicted the acoustic properties of single-reed instruments like the clarinet and saxophone. According to musicians, the reed itself has a significant impact on sound production and playing comfort. However, the physics of the reed remains incompletely understood, and reed makers are constantly seeking a deeper comprehension that could allow them to deduce physical parameters that more adequately account for the sensations of musicians. This is the reason why some researchers are interested in studying the behavior of reeds, either through the creation of physical models or through physical or perceptual experiments. The present paper proposes a review of these studies, structured into three sections. Firstly, the physics of single-reeds and single-reed instruments is exposed and described by various models of increasing complexity. The experimental studies about single cane reeds are then detailed in the second and third sections, which respectively deal with perceptual assessments and physical measurements. Finally, the conclusion synthesizes and brings together the findings from each section to provide a comprehensive overview of current knowledge while also highlighting prospects for future research.

Pörschmann Christoph, Arend Johannes M.

Previous studies on vertical or full-spherical directivity patterns of the human voice showed that the human voice has a slightly downward main radiation direction over a wide frequency range. This paper investigates the phoneme-dependencies of human voice radiation in the vertical plane and analyzes to what extent these characteristics affect the ground reflection and the sound incidence at a listener position. The results show that for most phonemes and below 800 Hz, the ground reflection is stronger than the direct sound component because of the downward-directed main radiation. On the contrary, between 800 Hz and 1.6 kHz, the main radiation direction is upward, probably mainly due to diffraction and reflections from the shoulders and the torso.