Scraping sounds and disgusting noises

Thirty-four horrible sounds have been examined in an Internet-based psychoacoustic experiment. This paper presents the results for the scraping and disgusting noises used. It is not understood why some humans find certain scraping noises, such as the sound of fingernails being scraped down a blackboard, so terrible. In this experiment, the variations in ratings with age, gender and location are examined. The results for one of the scraping sounds is consistent with the hypothesis suggested by others, that the response comes from a vestigial reflex related to the warning cries of monkeys. But this was not true for the actual recording of the fingernails scraping down a blackboard. An alternative hypothesis that the response is related to an audio–haptic interaction was tested and results indicated that this idea warrants further investigation. Other possible causes of the response, drawing on work concerning dissonance, are tentatively suggested. The disgusting sounds examined included the worst sound found in the experiment, the sound of someone vomiting. However, none of the disgusting sounds tested promoted responses consistent with a ‘disgust reaction’ based purely on survival instincts. Cultural factors might be important in our response to the disgusting sounds, with the influence of manners and etiquette being suggested as a possible factor

The effect of microphone wind noise on the amplitude modulation of wind turbine noise and its mitigation

Microphone wind noise can corrupt outdoor recordings even when wind shields are used. When monitoring wind turbine noise, microphone wind noise is almost inevitable because measurements cannot be made in still conditions. The effect of microphone wind noise on two Amplitude Modulation (AM) metrics is quantified in a simulation, showing that even at low wind speeds of 2.5 m/s errors of over 4 dBA can result. As microphone wind noise is intermittent, a wind noise detection algorithm is used to automatically find uncorrupted sections of the recording, and so recover the true AM metrics to within ±2/±0.5 dBA

Meta-Heuristic Optimization Methods for Quaternion-Valued Neural Networks

In recent years, real-valued neural networks have demonstrated promising, and often striking, results across a broad range of domains. This has driven a surge of applications utilizing high-dimensional datasets. While many techniques exist to alleviate issues of high-dimensionality, they all induce a cost in terms of network size or computational runtime. This work examines the use of quaternions, a form of hypercomplex numbers, in neural networks. The constructed networks demonstrate the ability of quaternions to encode high-dimensional data in an efficient neural network structure, showing that hypercomplex neural networks reduce the number of total trainable parameters compared to their real-valued equivalents. Finally, this work introduces a novel training algorithm using a meta-heuristic approach that bypasses the need for analytic quaternion loss or activation functions. This algorithm allows for a broader range of activation functions over current quaternion networks and presents a proof-of-concept for future work

A new variable tap-length LMS algorithm to model an exponential decay impulse response

This letter proposes a new variable tap-length least-mean-square (LMS) algorithm for applications in which the unknown filter impulse response sequence has an exponential decay envelope. The algorithm is designed to minimize the mean-square deviation (MSD) between the optimal and adaptive filter weight vectors at each iteration. Simulation results show the proposed algorithm has a faster convergence rate as compared with the fixed tap-length LMS algorithm and is robust to the initial tap-length choice

Dual energy X-ray absorptiometry compared with anthropometry in relation to cardio-metabolic risk factors in a young adult population: Is the ‘Gold Standard’ tarnished?

Background and Aims: Assessment of adiposity using dual energy x-ray absorptiometry (DXA) has been considered more advantageous in comparison to anthropometryfor predicting cardio-metabolic risk in the older population, by virtue of its ability to distinguish total and regional fat. Nonetheless, there is increasing uncertainty regarding the relative superiority of DXA and little comparative data exist in young adults. This study aimed to identify which measure of adiposity determined by either DXA or anthropometry is optimal within a range of cardio-metabolic risk factors in young adults. Methods and Results: 1138 adults aged 20 years were assessed by DXA and standard anthropometry from the Western Australian Pregnancy Cohort (Raine) Study. Cross-sectional linear regression analyses were performed. Waist to height ratio was superior to any DXA measure with HDL-C. BMI was the superior model in relation to blood pressure than any DXA measure. Midriff fat mass (DXA) and waist circumference were comparable in relation to glucose. For all the other cardio-metabolic variables, anthropometricand DXA measures were comparable. DXA midriff fat mass compared with BMI or waist hip ratio was the superior measure for triglycerides, insulin and HOMA-IR. Conclusion: Although midriff fat mass (measured by DXA) was the superior measure with insulin sensitivity and triglycerides, the anthropometricmeasures were better or equal with various DXA measures for majority of the cardio-metabolic risk factors. Our findings suggest, clinical anthropometry is generally as useful as DXA in the evaluation of the individual cardio-metabolic risk factors in young adults

Using scale modelling to assess the prehistoric acoustics of stonehenge

With social rituals usually involving sound, an archaeological understanding of a site requires the acoustics to be assessed. This paper demonstrates how this can be done with acoustic scale models. Scale modelling is an established method in architectural acoustics, but it has not previously been applied to prehistoric monuments. The Stonehenge model described here allows the acoustics in the Late Neolithic and early Bronze Age to be quantified and the effects on musical sounds and speech to be inferred. It was found that the stone reflections create an average mid-frequency reverberation time of (0.64 ± 0.03) seconds and an amplification of (4.3 ± 0.9) dB for speech. The model has a more accurate representation of the prehistoric geometry, giving a reverberation time that is significantly greater than that measured in the current ruin and a full-size concrete replica at Maryhill, USA. The amplification could have aided speech communication and the reverberation improved musical sounds. How Stonehenge was used is much debated, but these results show that sounds were improved within the circle compared to outside. Stonehenge had different configurations, especially in terms of the positions of the bluestones. However, this made inaudible changes to the acoustics, suggesting sound is unlikely to be the underlying motivation for the various arrangements

Applications of a hybrid method to a plate with simply supported boundary conditions

* The EN12354 building acoustics prediction standards are based on the statistical energy analysis (SEA) method. In a traditional SEA path analysis, lightweight or heavyweight materials have different principal paths that determine the sound insulation for the specified building acoustics frequency range (50Hz-5000Hz). Different building materials require different applications of the engineering method (EN12354) to determine in-situ sound insulation with flanking. A hybrid method, such as the (finite element method) FEM-SEA hybrid approach, offers an alternative theoretical framework to predict in situ sound insulation with the capacity to combine vastly different methods. In a hybrid model, different power flow contributions (due to the deterministic and direct-field energies) are naturally separated into different matrices. This work investigates the feasibility of using a hybrid model to predict sound insulation. The hybrid method is applied to three different materials. These models are compared against traditional SEA and infinite plate models

Students’ perceptions of school acoustics and the impact of noise on teaching and learning in secondary schools : findings of a questionnaire survey

This paper will present the design and findings of an online questionnaire survey of 11–16 year olds’ impressions of their school's acoustic environment, and of an experimental study into the effects of typical levels of classroom noise on adolescent's performance on numeracy and cognitive functioning tasks. Analysis of the responses to the questionnaire found that pupils who reported additional learning needs such as hearing impairment, speaking English as an additional language or receiving learning support reported being significantly more affected by poor school acoustics than pupils reporting no additional learning needs. Pupils attending suburban schools featuring cellular classrooms that were not exposed to a nearby noise sources were more positive about their school acoustics than pupils at schools with open plan classroom designs or attending schools that were exposed to external noise sources. The study demonstrates that adolescents are reliable judges of their school's acoustic environment, and have insight into the disruption to teaching and learning caused by poor listening conditions. Furthermore, pupils with additional learning needs are more at risk from the negative effects of poor school acoustics