Hasil untuk "Acoustics in engineering. Acoustical engineering"

Naik Suketu, Horikawa Justine, Lyne Lauren et al.

This paper presents the design, simulation, and experimental characterization of an ultrasonic transducer array system using open-source hardware for targeted non-invasive therapeutic applications. Two array geometries, Uniform Rectangular Array (URA) and Concentric Circular Array (CCA), were evaluated based on their pressure field distributions and beam focusing capabilities. The design process is described together with numerical simulations and experiments and reveals URA’s superior acoustic focusing and pressure uniformity. Developed largely through undergraduate research, this work represents an engineering proof-of-concept conducted at 40 kHz, which is below the medical therapeutic range (1–4 MHz). While this work does not imply its efficacy in biological systems or direct clinical applicability at present, it lays the groundwork for non-invasive therapeutic ultrasound systems with future design optimization aimed at applications such as cystic fibrosis and neurological conditions.

Schneiderwind Christian, De Sena Enzo, Neidhardt Annika

This paper presents two experiments investigating perceptual tolerances regarding deviations in the late reverberation of a room in augmented reality (AR) audio rendering. The study is based on binaural room impulse responses (BRIRs) measured with a KEMAR head-and-torso simulator in two seminar rooms with reverberation times (RTs) of about 0.4 s and 1.1 s. We implemented an algorithm to modify the RT while maintaining the spectral profile of the room’s reverberation. In a single stimulus listening test design, participants had to rate externalization, audiovisual plausibility, and room perception for different RT scalings. Differentiating between audiovisual plausibility for source and room helped capture the different perceptual phenomena. In this context, the concept of room acoustic signature preservation has also been proposed. The results indicate that in the reverberant room, RT deviation of 0.1 s already reveal that the acoustics of the room are different. However, plausible illusions in AR can be maintained despite significant perceptible deviations in RT, considering the original early room response. For originally short RT, audiovisual source plausibility is even robust towards larger RT modifications.

Mayuranath SureshKumar, Hanumanthrao Kannan

Classic problem-space theory models problem solving as a navigation through a structured space of states, operators, goals, and constraints. Systems Engineering (SE) employs analogous constructs (functional analysis, operational analysis, scenarios, trade studies), yet still lacks a rigorous systems-theoretic representation of the problem space itself. In current practice, reasoning often proceeds directly from stakeholder goals to prescriptive artifacts. This makes foundational assumptions about the operational environment, admissible interactions, and contextual conditions implicit or prematurely embedded in architectures or requirements. This paper addresses that gap by formalizing the problem space as an explicit semantic world model containing theoretical constructs that are defined prior to requirements and solution commitments. These constructs along with the developed axioms, theorems and corollary establish a rigorous criterion for unambiguous boundary semantics, context-dependent interaction traceability to successful stakeholder goal satisfaction, and sufficiency of problem-space specification over which disciplined reasoning can occur independent of solution design. It offers a clear distinction between what is true of the problem domain and what is chosen as a solution. The paper concludes by discussing the significance of the theory on practitioners and provides a dialogue-based hypothetical case study between a stakeholder and an engineer, demonstrating how the theory guides problem framing before designing any prescriptive artifacts.

Croënne Charles, Vasseur Jérôme O., Roux Laetitia et al.

Since World War II, there have been many efforts worldwide to design hull coatings for naval and underwater defense applications in order to reduce either noise radiated from the hull (discretion) or acoustic reflection from the hull (stealth). This paper presents a non-exhaustive review of concepts that have emerged since the iconic Alberich coating and highlights new trends and promising candidates, such as metamaterials, to improve the discretion and stealth performance of underwater defense systems. The need for acoustic materials for naval and underwater applications is first explained, along with some specific design requirements for acoustic coatings. Two coatings technologies, called micro-inclusion coatings and macro-inclusion coatings, are then successively reviewed. New trends in materials design for naval and underwater defense applications are also presented in the following section. This paper concludes by introducing the need for acoustic materials in the frame of new threats to the naval industries as well as other non-naval areas, opening new possibilities for their design.

Kaltenbacher Manfred, Scotti Thierry, Gaborit Mathieu et al.

Goestchel Quentin, Guillaume Gwenaël, Ecotière David et al.

Numerical sound propagation models include a wide range of methods with their own advantages depending on the physical phenomena under consideration. Due to its low-order scheme characteristic, the transmission line matrix (TLM) model is considered for coarse modeling of sound fields in complex outdoor environments. However, the space-time integration scheme of the method is dispersive and affects the free-field predictions. This paper extends a previous study of the numerical dispersion effect on the acoustic pressure field. An ideal case with specular reflections on a perfectly reflective ground is considered to represent the worst-case scenario, as the absence of absorption by the boundary maximizes the influence of numerical dispersion. First, a reminder of the model boundary conditions for specular reflection is provided, and the corresponding analytical solution is introduced as a reference to evaluate the reliability of the model. Then, a numerical experiment is presented and performed for different sound source characteristics. The result analysis shows that dispersion can induce misplaced interferences in the numerically simulated sound fields and the resulting errors are quantified in terms of sound pressure levels (SPL). Finally, an analytical comparison with a well-known finite difference numerical scheme gives a perspective on the TLM model performance regarding several applications.

Wittstock Volker, Bietz Heinrich, Schmelzer Martin

ISO tapping machines serve as absolute standards to describe the sensitivity of buildings and building elements in terms of impact noise. They consist of five hammers with a mass of 500 g each. The hammers strike the test object at a velocity corresponding to a free fall from a height of 4 cm with a time interval of 0.1 s between subsequent impacts. The force exerted by ISO tapping machines depends on the interaction between source and receiver. This interaction is governed by two independent phenomena: the mobility (mis)match and the restitution coefficient, i.e. the ratio of the hammer velocity after and before the impact. It is theoretically between 0 and 1 which introduces an uncertainty range of ±3 dB for the level of the interacting force. This contribution extends the existing equation for the blocked force of ISO tapping machines to cover multiple impacts since their occurrence is related to the force and the restitution coefficient. It is then shown experimentally that the restitution coefficient can cover the full theoretical range in practical situations. Fortunately, different types of tapping machines exhibit nearly the same restitution coefficient on the same receiver, and no systematic influence of the restitution coefficient on the hammer velocity before the impact or on the time intervals between impacts is observed. A first attempt to predict the restitution coefficient based on the mobility match between source and receiver did not give satisfactory results. A prediction of the restitution coefficient thus remains an open question.

Yuan Rui, Xu Zhangliang, Wei Song

The cantilever beam-based surface acoustic wave (SAW) accelerometer has a fast response time and high sensitivity, making it widely used in vibration detection of mechanical structures. In the fabrication and production of the sensor, the sensitivity and loss of the device have always been the key factors of concern. Here, a kind of SAW acceleration resonator based on nanopillar phononic crystals (PnCs) are proposed, and its properties of resonance frequency, phase velocity, quality (Q) factor, electromechanical coupling coefficient, resonance bandgap and acceleration sensitivity are numerically simulated by the finite element method (FEM). The influence of piezoelectric thin film (AlN) thickness and aluminum (Al) interdigital transducers (IDTs) thickness on the performance of the SAW resonator is analyzed with single pair IDT model simulations. It can be seen that PnCs can make SAW in the bandgap (766 MHz–864 MHz) spread along a fixed path or confined array area, effectively reducing acoustic energy loss. The presence of PnCs can improve the resonance frequency, phase velocity, Q factor and acceleration sensitivity of SAW resonator. Especially, the PnCs-SAW accelerometer exhibits a higher Q factor of 1135.3 and linear sensitivity of −4.9 kHz/g within the detection range of 0–70 g. This work is expected to provide a theoretical guidance for the development of SAW acceleration sensors with lower losses and higher sensitivity, offering new ideas for the diverse design of SAW devices.

Bellows Samuel D., Katz Brian F. G.

Calibration of material properties in room acoustics simulations is essential to producing realistic results. However, the number of available algorithms for calibrating room acoustics models remain limited. This work presents two methods for calibrating absorption coefficient values of reverberation time equations. The first uses a constrained least-squares estimate, while the second uses a constrained maximum-likelihood estimate. In addition to matching measured and estimated reverberation times, stochastic simulations demonstrate that the proposed methods decrease deviations in estimated absorption coefficient values relative to the initial estimate. A case study application of the calibration method to a scattering-delay-network reverberator and geometrical acoustics models suggests the portability of the approach in calibrating more complex room acoustic numerical simulations.

Lekshmi Murali Rani, Richard Berntsson Svensson, Robert Feldt

The integration of AI for Requirements Engineering (RE) presents significant benefits but also poses real challenges. Although RE is fundamental to software engineering, limited research has examined AI adoption in RE. We surveyed 55 software practitioners to map AI usage across four RE phases: Elicitation, Analysis, Specification, and Validation, and four approaches for decision making: human-only decisions, AI validation, Human AI Collaboration (HAIC), and full AI automation. Participants also shared their perceptions, challenges, and opportunities when applying AI for RE tasks. Our data show that 58.2% of respondents already use AI in RE, and 69.1% view its impact as positive or very positive. HAIC dominates practice, accounting for 54.4% of all RE techniques, while full AI automation remains minimal at 5.4%. Passive AI validation (4.4 to 6.2%) lags even further behind, indicating that practitioners value AI's active support over passive oversight. These findings suggest that AI is most effective when positioned as a collaborative partner rather than a replacement for human expertise. It also highlights the need for RE-specific HAIC frameworks along with robust and responsible AI governance as AI adoption in RE grows.

Daniel Mendez, Paris Avgeriou, Marcos Kalinowski et al.

Empirical Software Engineering has received much attention in recent years and became a de-facto standard for scientific practice in Software Engineering. However, while extensive guidelines are nowadays available for designing, conducting, reporting, and reviewing empirical studies, similar attention has not yet been paid to teaching empirical software engineering. Closing this gap is the scope of this edited book. In the following editorial introduction, we, the editors, set the foundation by laying out the larger context of the discipline for a positioning of the remainder of this book.

Kevin Hermann, Sven Peldszus, Jan-Philipp Steghöfer et al.

Software security is of utmost importance for most software systems. Developers must systematically select, plan, design, implement, and especially, maintain and evolve security features -- functionalities to mitigate attacks or protect personal data such as cryptography or access control -- to ensure the security of their software. Although security features are usually available in libraries, integrating security features requires writing and maintaining additional security-critical code. While there have been studies on the use of such libraries, surprisingly little is known about how developers engineer security features, how they select what security features to implement and which ones may require custom implementation, and the implications for maintenance. As a result, we currently rely on assumptions that are largely based on common sense or individual examples. However, to provide them with effective solutions, researchers need hard empirical data to understand what practitioners need and how they view security -- data that we currently lack. To fill this gap, we contribute an exploratory study with 26 knowledgeable industrial participants. We study how security features of software systems are selected and engineered in practice, what their code-level characteristics are, and what challenges practitioners face. Based on the empirical data gathered, we provide insights into engineering practices and validate four common assumptions.

Roßkopf Sarah, Kroczek Leon O.H., Stärz Felix et al.

Virtual Reality (VR) enables the presentation of realistic audio-visual environments by combining head-tracked binaural auralizations with visual scenes. Whether these auralizations improve social presence in VR and enable sound source localization comparable to that of real sound sources is yet unclear. Therefore, we implemented two sound source localization paradigms (speech stimuli) in a virtual seminar room. First, we measured localization continuously using a placement task. Second, we measured gaze as a naturalistic behavior. Forty-nine participants compared three auralizations based on measured binaural room impulse responses (BRIRs), simulated BRIRs, both with generic and individual head-related impulse responses (HRIRs), with loudspeakers and an anchor (gaming audio engine). In both paradigms, no differences were found between binaural rendering and loudspeaker trials concerning ratings of social presence and subjective realism. However, sound source localization accuracy of binaurally rendered sound sources was inferior to loudspeakers. Binaural auralizations based on generic simulations were equivalent to renderings based on individualized simulations in terms of localization accuracy but inferior in terms of social presence. Since social presence and subjective realism are strongly correlated, the implementation of plausible binaural auralizations is suggested for VR settings where high levels of (social) presence are relevant (e.g. multiuser interaction, VR exposure therapy).

Aurégan Yves

The acoustic behavior of a double annular resonator with flow is studied as a special case to illustrate the possibilities, but also the difficulties, offered by flow on the acoustic performance of metamaterials. Compared with the associated single resonator, the double resonator exhibits – in the lossless case – a transmission peak near the resonant frequency. This peak is associated with an evanescent out-of-phase coupling between the two resonators and is known in literature as “Autler-Townes splitting”. In measurements with a double resonator, this peak is strongly attenuated by viscous effects, to such an extent that it almost disappears. When a flow is added, even a very small one, a gain is created and the peak reappears close to the resonator frequency. As the average flow velocity increases, this gain can become sufficiently large for a whistling to appear.

Silitonga Dicky J., Declercq Nico F., Walaszek Henri et al.

Metal plate structures, crucial components in various industrial sectors, demand meticulous inspection methods for the maintenance of their structural integrity. This review article not only serves as a contemporary introduction to this research field but also underlines the vital role of this field in ensuring the safety and reliability of these structures. The study delves into Lamb wave generation and detection techniques, highlighting the challenges and advancements in transducer technologies. Two detailed case studies are presented to contextualize and illustrate the practical applications of these techniques. The first case study demonstrates the detection of weld joints and stiffeners in steel plates, particularly relevant to the shipbuilding industry. Through a combination of numerical simulations and experimental validations designed for this narrative, this study highlights the capability of the A0 Lamb wave mode in identifying these features. The second case study, equally supported by new experiments, focuses on detecting thickness reductions in aluminum plates using high-order Lamb modes in a multimodal excitation setup. This scenario simulates conditions such as corrosion or wear that induce material thinning. By creating blind holes of varying depths on one side of the plate and conducting inspections from the opposite side, the study demonstrates the method’s precision in identifying hidden defects. The case studies involving aluminum and steel specimens exemplify the efficacy of Lamb waves in the nondestructive evaluation of metal plates. They provide critical insights into the method’s ability to deliver precise and efficient detection of structural anomalies despite inherent challenges in signal interpretation and analysis.

Jukka Ruohonen, Kalle Hjerppe

Participatory citizen platforms are innovative solutions to digitally better engage citizens in policy-making and deliberative democracy in general. Although these platforms have been used also in an engineering context, thus far, there is no existing work for connecting the platforms to requirements engineering. The present paper fills this notable gap. In addition to discussing the platforms in conjunction with requirements engineering, the paper elaborates potential advantages and disadvantages, thus paving the way for a future pilot study in a software engineering context. With these engineering tenets, the paper also contributes to the research of large socio-technical software systems in a public sector context, including their implementation and governance.

Mehil B Shah, Mohammad Masudur Rahman, Foutse Khomh

Deep learning (DL) techniques have achieved significant success in various software engineering tasks (e.g., code completion by Copilot). However, DL systems are prone to bugs from many sources, including training data. Existing literature suggests that bugs in training data are highly prevalent, but little research has focused on understanding their impacts on the models used in software engineering tasks. In this paper, we address this research gap through a comprehensive empirical investigation focused on three types of data prevalent in software engineering tasks: code-based, text-based, and metric-based. Using state-of-the-art baselines, we compare the models trained on clean datasets with those trained on datasets with quality issues and without proper preprocessing. By analysing the gradients, weights, and biases from neural networks under training, we identify the symptoms of data quality and preprocessing issues. Our analysis reveals that quality issues in code data cause biased learning and gradient instability, whereas problems in text data lead to overfitting and poor generalisation of models. On the other hand, quality issues in metric data result in exploding gradients and model overfitting, and inadequate preprocessing exacerbates these effects across all three data types. Finally, we demonstrate the validity and generalizability of our findings using six new datasets. Our research provides a better understanding of the impact and symptoms of data bugs in software engineering datasets. Practitioners and researchers can leverage these findings to develop better monitoring systems and data-cleaning methods to help detect and resolve data bugs in deep learning systems.

Nadia Alshahwan, Mark Harman, Inna Harper et al.

In this paper we address the following question: How can we use Large Language Models (LLMs) to improve code independently of a human, while ensuring that the improved code - does not regress the properties of the original code? - improves the original in a verifiable and measurable way? To address this question, we advocate Assured LLM-Based Software Engineering; a generate-and-test approach, inspired by Genetic Improvement. Assured LLMSE applies a series of semantic filters that discard code that fails to meet these twin guarantees. This overcomes the potential problem of LLM's propensity to hallucinate. It allows us to generate code using LLMs, independently of any human. The human plays the role only of final code reviewer, as they would do with code generated by other human engineers. This paper is an outline of the content of the keynote by Mark Harman at the International Workshop on Interpretability, Robustness, and Benchmarking in Neural Software Engineering, Monday 15th April 2024, Lisbon, Portugal.

Marvin Wyrich, Justus Bogner

LinkedIn is the largest professional network in the world. As such, it can serve to build bridges between practitioners, whose daily work is software engineering (SE), and researchers, who work to advance the field of software engineering. We know that such a metaphorical bridge exists: SE research findings are sometimes shared on LinkedIn and commented on by software practitioners. Yet, we do not know what state the bridge is in. Therefore, we quantitatively and qualitatively investigate how SE practitioners and researchers approach each other via public LinkedIn discussions and what both sides can contribute to effective science communication. We found that a considerable proportion of LinkedIn posts on SE research are written by people who are not the paper authors (39%). Further, 71% of all comments in our dataset are from people in the industry, but only every second post receives at least one comment at all. Based on our findings, we formulate concrete advice for researchers and practitioners to make sharing new research findings on LinkedIn more fruitful.

Husstedt Hendrik, Hilgerdenaar Wiebke, Frenz Marlitt et al.

Short, impulse-like sounds such as slamming of a door or rattle of dishes can be uncomfortable for hearing aid users. Therefore, many hearing aids provide impulse (or transient) noise reduction (INR) that should reduce loud and short sounds without impairing desired signals. In this work, we want to address the question whether hearing aid users require this type of signal processing to experience impulse sounds similarly as normal-hearing listeners. For this purpose, we evaluated INR in six commercially available hearing aids with technical measurements and with test subjects. During the technical evaluation, we presented seven different impulse signals to the hearing aids attached to a head and torso simulator (HATS) and determined the C-weighted peak sound pressure levels (LC,peak) at the output in different configurations. For the evaluation with test subjects, the discomfort of the same impulse sounds was rated by 24 hearing-impaired and 20 normal-hearing subjects. All subjects rated the discomfort unaided, and the hearing-impaired subjects also while successively wearing all six hearing aids with and without activated INR. As a main conclusion, hearing aid users without INR did not experience more discomfort compared to normal-hearing listeners for most of the impulse signals tested including the most uncomfortable ones, but INR further reduced experienced discomfort. Moreover, the technical measurements were correlated with the subjective ratings on discomfort.