Hasil untuk "Acoustics in engineering. Acoustical engineering"

Buchholz Sina, Rennies Jan, van de Par Steven

Level-dependent hearing protectors enable listeners to perceive soft to medium-level sounds, while protecting the ear against hazardous high-level signals. The impact of these devices on localization ability due to changes in interaural cues is mostly unknown. This study investigated the influence of two hearing protectors (earplug and earmuff) in passive and one active setting on localizing two common alarm signals in noise at two signal levels compared to open ears. A listening test with 16 normal-hearing participants was conducted inside a horizontal array of 48 loudspeakers. Additionally, the stimuli were recorded with an artificial head in the same setup to calculate the corresponding occurring interaural cues. The results showed that especially one of the devices under test altered the perception of target direction, even causing alarms from one side to be misperceived as coming from the opposite side of the head. The technical measurements support these findings by revealing large changes of interaural level differences with this device compared to open ears, mostly aligning with participant responses. These findings indicate the need to test electronic hearing protectors regarding altered interaural cues to avoid safety risks due to impaired localization. Moreover, measurements of these cues can help predicting the perceived sound direction by human listeners.

Eduard Enoiu, Jean Malm, Gregory Gay

We explore the concept of folklore within software engineering, drawing from folklore studies to define and characterize narratives, myths, rituals, humor, and informal knowledge that circulate within software development communities. Using a literature review and thematic analysis, we curated exemplar folklore items (e.g., beliefs about where defects occur, the 10x developer legend, and technical debt). We analyzed their narrative form, symbolic meaning, occupational relevance, and links to knowledge areas in software engineering. To ground these concepts in practice, we conducted semi-structured interviews with 12 industrial practitioners in Sweden to explore how such narratives are recognized or transmitted within their daily work and how they affect it. Synthesizing these results, we propose a working definition of software engineering folklore as informally transmitted, traditional, and emergent narratives and heuristics enacted within occupational folk groups that shape identity, values, and collective knowledge. We argue that making the concept of software engineering folklore explicit provides a foundation for subsequent ethnography and folklore studies and for reflective practice that can preserve context-effective heuristics while challenging unhelpful folklore.

Nandalal Tharindu Danushka, Cillo Pierfrancesco, Ziegler Pascal et al.

The art of guitar craftsmanship has been a highly valued tradition, passed down through generations of renowned luthiers. While this centuries-old craft remains celebrated, the quest to define the tone quality of a guitar remains an enduring mystery. As a result, replicating the sound profile of highly valued guitars, renowned for their exceptional sound quality among musicians, has become a common goal among luthiers. Although geometrically identical copies were produced, audible differences were observed, which can mainly be attributed to the natural variation in the wood. The objective of this work is todevelop a guitar soundboard shape optimization methodology to compensate for material variability in terms of eigenfrequencies and eigenmodes, extending beyond the exceptional skills and intuition of luthiers. The significant computational demands arising from the numerous model evaluations required during shape optimization, present a notable challenge. To address this, we present a novel approach employingf parameterized shell finite element models with affine parameter dependency, integrated with a mesh morphing technique, which enables the application of parametric model order reduction. This approach substantially enhances computational efficiency in guitar soundboard optimization, while preserving both parameter dependence and mesh topology. This method can be efficiently applied to identify the optimal geometry of a guitar soundboard, taking into account the effects of material parameter variations through virtual prototyping. Although this study is primarily focused on guitar soundboards, the approach is also adaptable to other string instruments and their complete structures, as well as structures with sufficient resemblance to guitar soundboards.

da Silva Evangelista Marcus Vinicius, Freire Sérgio

The article discusses the effects of heavy practice mutes on violin sonority. Objective data (Long Term Average Spectrum and Loudness) from a parameterized sampling made with different types of performance and practice mutes, as well as modified devices and replicas made with lead, were employed in a comparative study. Specific effects of heavy practice mutes, such as the absence of energy transfer to the low frequency region, were observed. The text presents the mutes and describes the methodology, data processing, and the acoustic descriptors employed, followed by a discussion of the results.

Hopkins Carl, Lee Pyoung Jik, Gibbs Barry et al.

Acoustics research was established at the University of Liverpool in the middle of the 20th century in the department of physics which led to the formation of the Acoustics Research Unit (ARU) in the mid-1970s as part of the department of building engineering and then architecture. This article reviews the history and legacy of the research group that has worked on airborne and structure-borne sound over a 70 year period.

Maurerlehner Paul, Mayrhofer Dominik, Kaltenbacher Manfred et al.

Sound-absorptive materials such as foam can be described by the equivalent fluid (EF) model. The homogenized fluid’s acoustic behavior is thereby described by complex-valued, frequency-dependent acoustic material parameters. When transforming the acoustic wave equation for the EF model from the frequency domain to the time domain, convolution integrals arise. The auxiliary differential equation (ADE) method is used to circumvent the direct calculation of these convolution integrals. The wave equation and the coupled set of ordinary ADEs are solved in the time domain using the finite element (FE) method. The approach relies on approximating the complex-valued frequency response functions of the inverse equivalent bulk modulus and density by a sum of rational functions consisting of real and complex poles. The order of the rational function approximation defines the number of additionally introduced auxiliary variables per nodal degree of freedom. The presented FE formulation includes a narrow-band non-reflecting boundary condition (NRBC) for normal incidence. The implementation in openCFS shows optimal temporal and spatial convergence for a semi-infinite duct based on the analytic plane wave solution for harmonic excitation. The simulation of a pressure pulse propagating in an infinite EF domain with a scatterer demonstrates the capability for multidimensional, actual transient problems.

Kates James M., Lavandier Mathieu, Arehart Kathryn H. et al.

Introduction: The Hearing Aid Speech Perception Index version 2 (HASPI v2) is an intrusive speech intelligibility metric fitted to the intelligibility of sentence stimuli presented monaurally over headphones. It compares the time-frequency envelope modulation of a degraded signal, processed through a peripheral model matched to the subject’s audiogram, to the envelope modulation of an unprocessed noise-free signal processed through a normal-hearing (NH) peripheral model. This paper presents a binaural extension of HASPI v2. Methods: The binaural modifications are increasing the indicated hearing loss and providing a model of binaural interaction. The binaural HASPI was fit to binaural sentence-level intelligibility scores for NH and hearing-impaired (HI) subjects. The experimental conditions comprised combinations of room acoustics, spatial source configuration, noise, and simulated hearing-aid processing. Results: The Pearson correlation coefficients between the binaural HASPI predictions and the observed binaural intelligibility scores were 0.982 for the NH group, 0.981 for the HI group, and 0.983 for the combined groups. The corresponding RMS errors for intelligibility scores on a 0 to 1 scale were 0.050, 0.049, and 0.049. Discussion and Conclusions: The accuracy of the binaural HASPI is similar for HI and NH subjects. The accuracy compares favorably to that of existing binaural metrics.

Vladyslav Bulhakov, Giordano d'Aloisio, Claudio Di Sipio et al.

The introduction of large language models (LLMs) has enhanced automation in software engineering tasks, including in Model Driven Engineering (MDE). However, using general-purpose LLMs for domain modeling has its limitations. One approach is to adopt fine-tuned models, but this requires significant computational resources and can lead to issues like catastrophic forgetting. This paper explores how hyperparameter tuning and prompt engineering can improve the accuracy of the Llama 3.1 model for generating domain models from textual descriptions. We use search-based methods to tune hyperparameters for a specific medical data model, resulting in a notable quality improvement over the baseline LLM. We then test the optimized hyperparameters across ten diverse application domains. While the solutions were not universally applicable, we demonstrate that combining hyperparameter tuning with prompt engineering can enhance results across nearly all examined domain models.

Martin Obaidi, Marc Herrmann, Elisa Schmid et al.

Sentiment analysis is an essential technique for investigating the emotional climate within developer teams, contributing to both team productivity and project success. Existing sentiment analysis tools in software engineering primarily rely on English or non-German gold-standard datasets. To address this gap, our work introduces a German dataset of 5,949 unique developer statements, extracted from the German developer forum Android-Hilfe.de. Each statement was annotated with one of six basic emotions, based on the emotion model by Shaver et al., by four German-speaking computer science students. Evaluation of the annotation process showed high interrater agreement and reliability. These results indicate that the dataset is sufficiently valid and robust to support sentiment analysis in the German-speaking software engineering community. Evaluation with existing German sentiment analysis tools confirms the lack of domain-specific solutions for software engineering. We also discuss approaches to optimize annotation and present further use cases for the dataset.

Paris Avgeriou, Nauman bin Ali, Marcos Kalinowski et al.

Increasingly, courses on Empirical Software Engineering research methods are being offered in higher education institutes across the world, mostly at the M.Sc. and Ph.D. levels. While the need for such courses is evident and in line with modern software engineering curricula, educators designing and implementing such courses have so far been reinventing the wheel; every course is designed from scratch with little to no reuse of ideas or content across the community. Due to the nature of the topic, it is rather difficult to get it right the first time when defining the learning objectives, selecting the material, compiling a reader, and, more importantly, designing relevant and appropriate practical work. This leads to substantial effort (through numerous iterations) and poses risks to the course quality. This chapter attempts to support educators in the first and most crucial step in their course design: creating the syllabus. It does so by consolidating the collective experience of the authors as well as of members of the Empirical Software Engineering community; the latter was mined through two working sessions and an online survey. Specifically, it offers a list of the fundamental building blocks for a syllabus, namely course aims, course topics, and practical assignments. The course topics are also linked to the subsequent chapters of this book, so that readers can dig deeper into those chapters and get support on teaching specific research methods or cross-cutting topics. Finally, we guide educators on how to take these building blocks as a starting point and consider a number of relevant aspects to design a syllabus to meet the needs of their own program, students, and curriculum.

Filipe R. Cogo, Gustavo A. Oliva, Ahmed E. Hassan

The rapid advancement of AI-assisted software engineering has brought transformative potential to the field of software engineering, but existing tools and paradigms remain limited by cognitive overload, inefficient tool integration, and the narrow capabilities of AI copilots. In response, we propose Compiler.next, a novel search-based compiler designed to enable the seamless evolution of AI-native software systems as part of the emerging Software Engineering 3.0 era. Unlike traditional static compilers, Compiler.next takes human-written intents and automatically generates working software by searching for an optimal solution. This process involves dynamic optimization of cognitive architectures and their constituents (e.g., prompts, foundation model configurations, and system parameters) while finding the optimal trade-off between several objectives, such as accuracy, cost, and latency. This paper outlines the architecture of Compiler.next and positions it as a cornerstone in democratizing software development by lowering the technical barrier for non-experts, enabling scalable, adaptable, and reliable AI-powered software. We present a roadmap to address the core challenges in intent compilation, including developing quality programming constructs, effective search heuristics, reproducibility, and interoperability between compilers. Our vision lays the groundwork for fully automated, search-driven software development, fostering faster innovation and more efficient AI-driven systems.

Roberto Verdecchia, Justus Bogner

While mastered by some, good scientific writing practices within Empirical Software Engineering (ESE) research appear to be seldom discussed and documented. Despite this, these practices are implicit or even explicit evaluation criteria of typical software engineering conferences and journals. In this pragmatic, educational-first document, we want to provide guidance to those who may feel overwhelmed or confused by writing ESE papers, but also those more experienced who still might find an opinionated collection of writing advice useful. The primary audience we had in mind for this paper were our own BSc, MSc, and PhD students, but also students of others. Our documented advice therefore reflects a subjective and personal vision of writing ESE papers. By no means do we claim to be fully objective, generalizable, or representative of the whole discipline. With that being said, writing papers in this way has worked pretty well for us so far. We hope that this guide can at least partially do the same for others.

Joe Tan, Jordan Cheer, Charlie House

Nonreciprocal acoustic devices have been shown to be able to control incident waves propagating in one direction whilst allowing incident waves propagating in the opposite direction to be transmitted without modification. Nonreciprocal sound transmission, typically, has been achieved by introducing nonlinearities or directional biasing through fluid motion or spatiotemporal modulation of resonant cavities. However, the spatial arrangement of these approaches creates preferential characteristics in one direction such that the direction of the nonreciprocal behaviour is fixed and, thus, they are not straightforwardly reconfigurable. To address this issue, it has previously been revealed that feedforward wave-based active controllers can be employed to drive a single subwavelength active unit cell to achieve broadband nonreciprocal sound transmission or absorption in a one-dimensional linear acoustic system. Extending this concept, this paper investigates how the feedforward wave-based active controller can be used to drive an array of subwavelength active unit cells forming a metasurface to achieve broadband nonreciprocal sound absorption over a two-dimensional plane. Through simulation and experimental studies, this paper shows that active wave-based absorption control systems can achieve broadband nonreciprocal sound absorption when the incident waves are generated by normally and obliquely positioned primary sources.

Bække Birgitte S., Agerkvist Finn T., Lucklum Frieder et al.

The balanced armature receiver is a miniature loudspeaker used in hearing aids. When the receiver produces sound, it also exhibits structural vibrations that propagate as both sound and vibrations within the hearing aid structure. These are picked up by the microphones, resulting in feedback. For the first time, a multi-mass lumped element model, representing the mechanical vibrations of the balanced armature receiver, is presented in the literature. The model distinguishes the internal, moving components to capture how their movement propagates to the chassis structure. Component mass is assigned to model their movement, while their mechanical couplings are captured by spring-damper connections. The (ideally) static components (chassis etc.) are lumped into one mass, whose movement represents the structural vibrations that propagate to the hearing aid shell. The model captures the overall behavior of the mechanical system, which means that with physically sound parameter input, we can predict how parameter changes will impact the response. The thorough treatment of the interplay between the components provides a detailed model response that is completed by parameter properties determined through measurements and analytical methods. Validation against the measured electrical and mechanical response, shows that all main features including resonances are explained by the model.

Sluyts Yannick, Houvenaghel Marijke, Morel Anne-Francoise et al.

Sir Christopher Wren (1632–1723) was responsible for the rebuilding of 52 parish churches in 17th-century London after the Great Fire of 1666. In literature his parish church designs are often referred to as “auditorium churches”, as Wren himself claimed that he treated visibility and audibility as priorities in his designs. Proof of this can be found in his own manuscripts where he mentions a few practical recommendations regarding room acoustics for churches. In the 17th century, contemporary scientists, amongst whom Robert Hooke (1635–1703), took interest in studying the propagation of sound through the air and formulate theories to explain the occurrence of echoes. However, a more comprehensive theory of reverberation in rooms was only developed later in the 20th century. Hence the question whether Wren’s churches were in fact “fitted for auditories” [Wren et al., Letter to a Friend on the Commission for Building Fifty New Churches (1711). Parentalia, The Life of Sir Christopher Wren, Knt., London, WS, pt. 2, sec. 9, 318-321, Transcript in WS, 9 (1750) 15–18] and what informed Wren in the design of his “auditorium churches”. In this paper the parish church of St Stephen’s Walbrook London is evaluated acoustically using a modern approach. Measured impulse responses were used to calibrate a reconstructed CAD model of the church in its 17th-century condition. Through different acoustic model scenarios, we were able to put Wren’s own recommendations concerning the acoustics of his parish church designs to the test. The speech intelligibility in St Stephen’s Walbrook was deemed adequate in its 17th-century configuration, the application of at least one of his recommendations leading to an improvement. It could not be shown, however, that Wren had full control over the room acoustic conditions in the church.

Jürgensen Lukas, Denk Florian, Husstedt Hendrik

One main functionality of hearing aids is restoring audibility. This means that low sound pressure levels are amplified above the elevated hearing threshold, and higher sound pressure levels do not exceed the individual uncomfortable loudness level (UCL). To this end, hearing aids provide frequency-dependent dynamic range compression which is denoted as hearing aid channels (HACs) in the recently published standard IEC 60118-16. As an increasing number of HACs, among other features, is one main feature to differentiate between price or technology levels, IEC 60118-16 includes a measurement procedure to verify the number of HACs. In this work, we verify this test procedure with a research hearing aid (RHA), and evaluate six commercial hearing aids of three different manufacturers and two technology levels. These results demonstrate the possibilities and limitations of the new test procedure. Furthermore, we introduced an extension of this test procedure with a channel-specific compression setting to overcome limitations and to get a deeper insight into the functionality of HACs in hearing aids. These results show that many HACs of commercial devices are coupled to neighboring frequencies, and that different strategies are used across manufacturers to adapt the number of HACs for different technology levels.

Scanlan Jamie, Umnova Olga, Li Francis

The percussion response of long bone has the potential to be used as a measure of bone strength for Osteoporosis detection. Modelling the vibration response requires describing the shape of the long bone which can have several features. An overly simplistic model of the shape does not give enough insight into their influence on the vibration response. This paper identifies the key features of the shape of a tibia and femur bone (cross-sectional shape, twist, and scale of the ends) and investigates their individual effects on the eigenfrequencies using finite element modelling. A femur and tibia model are dissected at the thicker ends and length adjusted to isolate the influence of the proximal and distal ends on the eigenfrequencies. Selected cross-sectional shapes are investigated to simplify the modelling and compared to real bone cross-sections and results. The twist is added across the longitudinal axis of the model producing an inline twist to the cross-section and resulting in a 1.5–2.5% decrease in frequencies per 20° of twist. The scale of the cross-sections at the ends of the model are increased along a set length of the bone to emulate the larger proximal and distal end of the long bones. The results show that any model for the vibro-acoustic response of long bones needs to include asymmetry in the cross-section as well as the scaling of the ends.

Pégeot Martin, Colinot Tom, Doc Jean-Baptiste et al.

Self-sustained musical instruments, such as wind or bowed string instruments, are complex nonlinear systems. They admit a wide variety of regimes, which sometimes coexist for certain values of the control parameters. This phenomenon is known as multistability. With fixed parameters, the selection of a regime and the shape of the transient depend not only on the values of the control parameters, but also on the initial conditions. In this article, we focus on the statistical influence of initial conditions on regime selection and transient duration. An existing sample-based method called basin stability is presented to calculate the probability of occurrence of each regime. A second sample-based method is proposed for the calculation of the probability density function of transient durations. Additionally, a study taking into account specific control scenarios is presented to highlight the influence of the distribution of initial conditions considered for the statistical methods. These methods are presented on a Van der Pol oscillator seen as a prototypical musical instrument model. They are then applied to a physical model of trumpet, to demonstrate their potential for a high dimensional self-oscillating musical instrument. Finally, their interest regarding questions of playability is discussed.

Sonja Hyrynsalmi, Ella Peltonen, Fanny Vainionpää et al.

In the extant literature, there has been discussion on the drivers and motivations of minorities to enter the software industry. For example, universities have invested in more diverse imagery for years to attract a more diverse pool of students. However, in our research, we consider whether we understand why students choose their current major and how they did in the beginning decided to apply to study software engineering. We were also interested in learning if there could be some signs that would help us in marketing to get more women into tech. We approached the topic via an online survey (N = 78) sent to the university students of software engineering in Finland. Our results show that, on average, women apply later to software engineering studies than men, with statistically significant differences between genders. Additionally, we found that marketing actions have different impacts based on gender: personal guidance in live events or platforms is most influential for women, whereas teachers and social media have a more significant impact on men. The results also indicate two main paths into the field: the traditional linear educational pathway and the adult career change pathway, each significantly varying by gender

Jieke Shi, Zhou Yang, David Lo

Large Language Models (LLMs) have recently shown remarkable capabilities in various software engineering tasks, spurring the rapid growth of the Large Language Models for Software Engineering (LLM4SE) area. However, limited attention has been paid to developing efficient LLM4SE techniques that demand minimal computational cost, time, and memory resources, as well as green LLM4SE solutions that reduce energy consumption, water usage, and carbon emissions. This paper aims to redirect the focus of the research community towards the efficiency and greenness of LLM4SE, while also sharing potential research directions to achieve this goal. It commences with a brief overview of the significance of LLM4SE and highlights the need for efficient and green LLM4SE solutions. Subsequently, the paper presents a vision for a future where efficient and green LLM4SE revolutionizes the LLM-based software engineering tool landscape, benefiting various stakeholders, including industry, individual practitioners, and society. The paper then delineates a roadmap for future research, outlining specific research paths and potential solutions for the research community to pursue. While not intended to be a definitive guide, the paper aims to inspire further progress, with the ultimate goal of establishing efficient and green LLM4SE as a central element in the future of software engineering.