Search Results (38)

This study introduces an open-source hybrid shape optimization workflow for acoustic wave problems that integrates acoustic wave propagation analysis with a two-stage optimization strategy. A coarse Parameter Sweep (PS) is first used for feasibility screening and global exploration, followed by derivative-free local refinement using the Nelder–Mead (NM) method. The framework is demonstrated on three benchmark problems: (i) an acoustic horn optimized for improved impedance matching and reduced reflections, (ii) a noise barrier reshaped to minimize acoustic pressure in the shadow zone, and (iii) a crescent-shaped scatterer designed to attenuate downstream pressure amplitude. Across all cases, the PS–NM strategy achieved lower objective values than baseline-initialized local optimization, at the expense of increased computational cost. All analyses were performed in the open-source FEniCS environment within Jupyter Notebooks. Comparisons with published results support the accuracy and consistency of the implementation. By combining accessibility with flexibility, the framework provides a reproducible methodology for acoustic shape optimization. Potential extensions include multi-objective formulations, frequency-adaptive designs, improved constraint-handling strategies, and integration with metamaterial concepts. Full article

In historic districts, the audiovisual environment plays an important role in shaping both cultural expression and spatial experience. However, the influence of acoustic and visual environmental factors on perceived street vitality remains insufficiently understood. Taking the Shangxiahang Historic District in Fuzhou as a case study, this paper employs on-site sound pressure level measurements, panoramic visual data collection, questionnaire surveys, principal component analysis, correlation analysis, and multiple regression analysis to systematically examine the effects of acoustic and visual environmental factors on perceived street vitality. The results indicate that traditional cultural sounds and natural sounds have a significant positive impact on perceived street vitality, while construction noise and tour guide’s horn sound exhibit negative effects. Regarding the visual environment, street and alley spaces, traditional architecture, greenery, and the sky are all important factors in promoting perceived street vitality. Further regression analysis reveals that the perception rate of street and alley spaces has the strongest influence, followed by the perception rate of traditional architecture, the perceived frequency of folk activity sounds, preference for greenery, and the perception rate of the sky. These findings demonstrate that perceived street vitality in historic districts does not depend on a single environmental factor but rather arises from synergistic interaction between culturally meaningful acoustic cues and legible spatial forms. These results offer practical implications for multisensory design and vitality-oriented regeneration in historic districts. Full article

In this work, the propagation of acoustic waves in shell trumpets is explored, and the overtones generated by them are studied. We consider different shell geometries, for which their particular morphology is taken into account. This impacts the fundamental frequencies as well as the overtones. An analytical model based on differential equations is developed to predict these overtones and compared with real recordings of some shell trumpets belonging to several collections in Mexico (experimental results). As a consequence, the notes of archaeological shells that cannot be played due to their physical damage are estimated. Full article

Falls pose severe risks to vulnerable populations, particularly the elderly and individuals with adverse neurological conditions, necessitating reliable and non-obstructive detection systems. While previous multi-modal approaches utilizing video and audio have demonstrated strong performance, they face significant limitations regarding sensitivity to environmental noise. This paper presents a robust, video-only fall detection framework that eliminates reliance on acoustic data to enhance universality. We conduct a comprehensive comparative analysis of five optical flow (OF) algorithms—Horn–Schunck, Lucas–Kanade (LK), LK-Derivative of Gaussian, Farneback, and the spectral method SOFIA—to determine the range of applicability of each technique for capturing fall dynamics. Beyond detection accuracy, we investigate the computational efficiency of each configuration. This optimized, privacy-centric pipeline offers a scalable solution for continuous monitoring in home and clinical settings, addressing the critical need for immediate intervention following high-impact falls. Full article

Insulation deterioration is the leading cause of premature failures in high-voltage (HV) power equipment, with partial discharge (PD) serving as a key indicator of insulation health. This study introduces a novel compact PD sensor assembly that integrates fiber Bragg grating (FBG) with an exponential acoustic horn to enhance the sensitivity of PD detection. The horn’s geometry effectively collects ultrasonic emissions from the PD, concentrating the acoustic energy to amplify the force on the FBG located at its focal point. To further enhance signal transduction, the FBG is mounted on a fixed solid structure engineered to resonate at higher ultrasonic frequencies that closely align with the dominant acoustic components generated by PD activity, ensuring improved strain amplification and optimal sensitivity. This results in measurable wavelength shifts, which are used for PD detection. A fiber Bragg grating analyzer interrogates the reflected spectra, providing real-time PD detection during HV operations. The effectiveness of the system was validated against the IEC 60270 standard method using laboratory models that emulated corona and surface discharge. The laboratory experiments demonstrated a significant sensitivity of 2.2 pm/Pa and a favorable signal-to-noise ratio of ~21 dB for the proposed sensor module. The dielectric construction of the sensor module, lightweight design, and resistance to electromagnetic interference make it suitable for harsh HV environments and the long-term condition monitoring of HV power equipment. Full article

Herbage intake by grazers and browsers is of fundamental importance to agricultural ecosystems worldwide but is also notoriously difficult to quantify. The intake process is mediated by herbage comminution in the mouth. The attendant chew actions generate sound bursts that can be detected acoustically and analyzed to help elucidate the entire process. Goats consuming a single plant species were acoustically monitored in order to (i) determine the sensitivity of the chewing effort to the large variation in bite mass and satiety level and (ii) estimate how well the amount of herbage consumed can be predicted by counting chews. Experiments used hand-constructed patches containing bite-sized carob (Ceratonia siliqua L.) leaflets of a pre-determined mass that were presented to six goats, individually, with acoustic sensors attached to their horns. Experiment 1 determined the chewing effort and the sequence of bites and chews for three bite masses across five levels of total intake. Experiment 2 determined the chewing effort and the chew sequence at three levels of satiety, achieved by control of the feeding regime, using a single bite mass across three levels of total intake. In Experiment 1, the global chewing coefficient was ≈4 chews g⁻¹ fresh mass ingested (≈10 chews g⁻¹ dry matter). For an individual animal, the chewing coefficient was fairly stable, being influenced mildly by bite mass, but the variation between animals was large. In Experiment 2, the chewing coefficient was again fairly stable in an individual animal, although the chewing effort was slightly elevated at low satiety. At the population level, and for the most relevant range of intake levels, inverse regression of the pooled data from both experiments estimated the two-sided 95% confidence interval of the predicted intake of carob leaves to be <10% of the predicted value. If chewing coefficients can be estimated locally, usefully precise intake predictions should be attainable for the tested vegetation. These results are promising for the future potential of acoustic monitoring, although significant challenges remain. Full article

This paper presents a comparative analysis of the influence of Fused Deposition Modeling (FDM) parameters—specifically material type, infill geometry, and density—on the vibro-acoustic characteristics of loudspeaker enclosures. The enclosures were designed as exponential horns to intensify resonance phenomena for precise evaluation. Twelve unique configurations were fabricated using three materials with distinct damping properties (PLA, ABS, wood-composite) and three internal geometries (linear, honeycomb, Gyroid). Key vibro-acoustic properties were assessed via digital signal processing of recorded audio signals, including relative frequency response and time-frequency (spectrogram) analysis, and correlated with a predictive Finite Element Analysis (FEA) model of mechanical vibrations. The study unequivocally demonstrates that a material with a high internal damping coefficient is a critical factor. The wood-composite enabled a reduction in the main resonance amplitude by approximately 4 dB compared to PLA with the same geometry, corresponding to a predicted 86% reduction in mechanical vibration. Furthermore, the results show that a synergy between a high-damping material and an advanced, energy-dissipating infill (Gyroid) is crucial for achieving high acoustic fidelity. The wood-composite with 10% Gyroid infill was identified as the optimal design, offering the most effective resonance damping and the most neutral tonal characteristic. This work provides a valuable contribution to the field by establishing a clear link between FDM parameters and acoustic outcomes, delivering practical guidelines for performance optimization in personalized audio systems. Full article

A new species of the genus Boulenophrys (Anura, Megophryidae) is described from Mount Lushan, Jiangxi Province, China, long considered to be Boulenophrys boettgeri. Phylogenetic analyses based on mitochondrial COI and 16S rRNA genes show that the new species forms a sister clade to B. jinggangensis, with an uncorrected COI p-distance of 3.7%, confirming its status as a distinct species. Morphologically, it differs from all known congeners by a unique combination of characters, and from its closest relative B. jinggangensis by having the following traits: (1) larger adult body size (adult males SVL 42.7–44.7 mm; adult females 46.0–50.3 mm); (2) heels not meeting when hindlimbs are flexed at right angles to the body axis; (3) smaller horn-like tubercle on the upper eyelid; and (4) relative finger lengths (I < II < IV < III). Acoustically, the new species differs markedly from B. jinggangensis in nearly all parameters of its advertisement calls. This discovery increases the known species diversity of Boulenophrys in Jiangxi Province and provides baseline data for further biodiversity conservation efforts in the Mount Lushan region. Full article

The increasing reliance on lithium-ion batteries (LIBs) in electric vehicles (EVs) has intensified the need for structurally resilient and lightweight protective enclosures that can withstand mechanical abuse during crashes. This study addresses the challenge by drawing inspiration from the hierarchical geometry of bighorn sheep horns to design a bio-inspired battery frame with improved crashworthiness. A multilayered structure, replicating both the internal and external features of the horn, was fabricated using Fused Deposition Modeling (FDM) with Acrylonitrile Butadiene Styrene (ABS) and carbon fiber composite (CFC) materials. The experimental evaluation involved tensile and compression testing, Izod impact tests, digital image correlation (DIC), and acoustic emission (AE) monitoring for full-field strain mapping, aiming to assess structural performance under various loading scenarios. Results demonstrate that the bioinspired designs exhibit enhanced energy absorption, mechanical strength, and strain distribution compared to conventional configurations. The improved vibration response and damage tolerance observed in structured samples suggest their potential for application in battery protection systems. This work underscores the feasibility of leveraging natural design principles to engineer robust, lightweight enclosures for advanced energy storage systems, contributing to safer and more reliable EV technologies. Full article

In modern industry, the spring full-lift safety valve is a key device for safe pressure relief of pressure-bearing systems. Its valve seat sealing surface is easily damaged after long-term use, causing internal leakage, resulting in safety hazards and economic losses. Therefore, it is of great significance to quickly and accurately diagnose its internal leakage state. Among the current methods for identifying fluid machinery faults, model-based methods have difficulties in parameter determination. Although the data-driven convolutional neural network (CNN) has great potential in the field of fault diagnosis, it has problems such as hyperparameter selection relying on experience, insufficient capture of time series and multi-scale features, and lack of research on valve internal leakage type identification. To this end, this study proposes a safety valve internal leakage identification method based on high-frequency FPGA data acquisition and improved CNN. The acoustic emission signals of different internal leakage states are obtained through the high-frequency FPGA acquisition system, and the two-dimensional time–frequency diagram is obtained by short-time Fourier transform and input into the improved model. The model uses the leaky rectified linear unit (LReLU) activation function to enhance nonlinear expression, introduces random pooling to prevent overfitting, optimizes hyperparameters with the help of horned lizard optimization algorithm (HLOA), and integrates the bidirectional gated recurrent unit (BiGRU) and selective kernel attention module (SKAM) to enhance temporal feature extraction and multi-scale feature capture. Experiments show that the average recognition accuracy of the model for the internal leakage state of the safety valve is 99.7%, which is better than the comparison model such as ResNet-18. This method provides an effective solution for the diagnosis of internal leakage of safety valves, and the signal conversion method can be extended to the fault diagnosis of other mechanical equipment. In the future, we will explore the fusion of lightweight networks and multi-source data to improve real-time and robustness. Full article

Motorcycle horns are a dominant source of urban noise in many Southeast Asian cities, driven by high two-wheeler density and limited public transport infrastructure. Although automobiles have been in use for over a century, regulations governing horn design and volume control remain inadequate. This study investigates horn use behavior in Vietnamese urban traffic, identifying distinct acoustic patterns categorized as “attention” and “warning” signals. Measurements conducted in an anechoic chamber reveal that these patterns can increase sound pressure levels by up to 17 dB compared to standard horn use, with notable differences in frequency components. These levels often exceed the daytime noise thresholds recommended by the World Health Organization (WHO), indicating potential risks for adverse health outcomes, such as elevated stress, hearing damage, sleep disturbance, and cardiovascular effects. The findings are contextualized within broader efforts to manage traffic noise in rapidly developing urban areas. Drawing parallels with studies on aircraft noise exposure in Japan, this study suggests that long-term exposure, rather than peak noise levels alone, plays a critical role in shaping community sensitivity. The study results support the need for updated noise regulations that address both the acoustic and perceptual dimensions of road traffic noise. Full article

For animals that typically live in groups or family units, being isolated from their conspecifics can be stressful. Horned passalus beetles (genus Odontotaenius), inhabit decaying logs in forests in the eastern United States. While not a truly social insect, they do coinhabit logs and maintain family units, and they are known to communicate with each other using stridulations that produce varying types of “chirps”. This project investigated if the auditory environment within these logs affects the beetles, specifically by exposing larval or adult beetles in a lab to sounds of (1) other beetles chirping, (2) no sound, or (3) the sounds of crickets, for varying time periods. Beetles were weighed before and after the exposures to determine changes in body mass. Beetle larvae experienced the slowest growth rates when listening to crickets or no sound, and the highest growth rates when hearing adult chirps. Adult beetles experienced mass losses in the treatments without beetle sounds, and this finding was replicated in three different experiments. The mass loss was greatest in the experiment that had the longest duration. The fact that the mass losses were observed in both the silent treatment, plus the treatment of cricket sounds, indicates that the lack of conspecific sounds (of other passalus beetles) was driving the effect. Surprisingly, there was no added effect of nematode parasitism on adult weight loss. Also, there was no evidence that the beetles were foraging less in the treatments without beetle sound, which suggest those beetles were experiencing elevated metabolism. The reduced growth rates and lost mass are signs that the beetles experienced chronic stress when deprived of the sounds of their kin. Combined, these experiments demonstrate how the acoustic environment, and especially the sounds of other beetles, is important to the lives of these insects, perhaps owing to the fact that they live in dark tunnels. Full article

This work presents the design and implementation of an emergency sound detection and localization system, specifically for sirens and horns, aimed at enhancing road safety in automotive environments. The system integrates specialized hardware and advanced artificial intelligence algorithms to function effectively in complex acoustic conditions, such as urban traffic and environmental noise. It introduces an aerodynamic structure designed to mitigate wind noise and vibrations in microphones, ensuring high-quality audio capture. In terms of analysis through artificial intelligence, the system utilizes transformer-based architecture and convolutional neural networks (such as residual networks and U-NET) to detect, localize, clean, and analyze nearby sounds. Additionally, it operates in real-time through sliding windows, providing the driver with accurate visual information about the direction, proximity, and trajectory of the emergency sound. Experimental results demonstrate high accuracy in both controlled and real-world conditions, with a detection accuracy of 98.86% for simulated data and 97.5% for real-world measurements, and localization with an average error of 5.12° in simulations and 10.30° in real-world measurements. These results highlight the effectiveness of the proposed approach for integration into driver assistance systems and its potential to improve road safety. Full article

Acoustic monitoring facilitates the detailed study of herbivore grazing by generating a timeline of sound bursts associated with jaw movements (JMs) that perform bite or chew actions. The unclassified stream of JM events was used here in an observational study to explore the notion of “grazing time”. Working with shepherded goat herds in a wooded landscape, a horn-based acoustic sensor with a vibration-type microphone was deployed on a volunteer animal along each of 12 foraging routes. The software-generated timeline of unclassified JMs contained a total of 334,582 events. After excluding rumination bouts, minutely JM rates showed a broad, non-normal distribution, with an overall mean of 61 JM min⁻¹. The frequency distribution of inter-JM interval values scaled logarithmically, with a peak in the region of 0.43 s representing a baseline interval that generates the unconstrained, more-or-less regular, rhythm of jaw movement (≈140 JM min⁻¹). This rhythm was punctuated by interruptions, for which duration scaled logarithmically, and which were primarily related to the search phase of the intake process. The empirical time accumulation curve shows the contribution of the inter-JM interval to the total foraging time and provides a penetrating profile of how the animal interacted with the foraging environment. The sum total of time along a foraging route spent at a near-potential JM rate was only ≈1 h, whereas sub-potential rates containing intervals as long as ≈30 s accounted for the bulk of the foraging route. The dimensionless behavioral grazing intensity was defined as the product of the number of ingestive JMs performed and the baseline interval, divided by the duration of the foraging route (excluding rumination). Values were mostly <0.5 for the foraging routes examined. This has implications for how animal presence should be translated to grazing pressure and for how long animals need to forage to meet their nutritional requirements. Full article

Katydids employ acoustic signals to communicate with others of their species and have evolved to generate sounds by coupling the anatomical structures of their forewings. However, some species have evolved to implement an additional resonance mechanism that enhances the transmission and sound pressure of the acoustic signals produced by the primary resonators. Secondary resonators, such as burrow cavities or horn-shaped structures, are found in the surrounding environment but could also occur as anatomical modifications of their bodies. Chamber-like structures have been described in species of katydids with modified pronota or wings. It has been shown that these modified structures directly affect the transmission and filtering of acoustic signals and can function as a Helmholtz resonator that encapsulates the primary sound source. By morphological and acoustic analysis, we describe a new genus of Conocephalinae and investigate the physical properties of their sound production structures for three new species from the Andes of Colombia and Ecuador. Males of the new genus, here described as Tectucantus n. gen., have a characteristic inflated pronotum enclosing the reduced first pair of wings and extending rearward over the first abdominal segments. We test the hypothesis that the pronotal cavity volume correlates with the carrier frequency of specific calls. The cavity of the pronotal chamber acts as a Helmholtz resonator in all three Tectucantus species and, potentially, in other distantly related species, which use similar secondary body resonators. Full article