Understanding urban and natural soundscapes

The concept of soundscape has garnered increasing research attention over the last decade for studying and designing the sonic environment of public spaces. It is therefore critical to advance knowledge on how the soundscape of a place is evoked by its sonic environment, given visual, cultural, and situational contexts. Working Group 1 of the COST action "Soundscapes of European cities and landscapes" revolves around this question. In our current understanding the sounds that are heard during normal activities in a place trigger meaning and emotions based on the matching with expectations of the people using and acting in that place. This complete package of human experience in relation to the sonic environment can be named the soundscape. In terms of design, this understanding opens several opportunities. The designer can decide which sounds should be heard and try to make this happen by guiding the attention to particular sounds or simply remove, add or shape sounds. In doing so, he or she should keep in mind expectations of the local users. Expectations and meaning might be changed by suitable design of non-sonic features of the environment including besides the obvious visual context also the openness, lighting, local climate, etc. Bringing these concepts to practice requires new tools and methodologies.Peer reviewe

Long-Wavelength Quantum Well Infrared Photodetectors

A majority of IR sensors used for imaging arrays operating in the long-wavelength IR region between 8 µm-12 µm are based on mercury cadmium telluride (HgCdTe). This material system is unable to satisfy all the requirements imposed by modem applications. Structural difficulties due to poor uniformity, high defect densities, and weak bond strengths cause difficulties in manufacturing large IR focal plane array cameras. As an alternative, quantum well infrared photodetectors (QWIPs) utilising intersubband absorption between gallium arsenide (GaAs) wells and aluminium gallium arsenide (AIGaAs) barriers were perfected. These QWIPs possess better uniformity in comparison to HgCdTe detectors, and QWIP imaging arrays have recently become commercially available. However, the responsivity of GaAs/AlGaAs QWIPs is still lower than HgCdTe detectors. To further improve the responsivity of QWIP detectors, QWIPs with wells or barriers of GaInAsP instead of AlGaAs have been developed. Results of QWIPs made from the material systems GaAs/GaInP, GaInAs(P)/InP, (Al)GaInAs/InP, and GaInAs/AllnAs have been discussed

Unsupervised Monitoring System for Predictive Maintenance of High Voltage Apparatus

The online monitoring of a high voltage apparatus is a crucial aspect for a predictive maintenanceprogram. Partialdischarges(PDs)phenomenaaffecttheinsulationsystemofanelectrical machine and\u2014in the long term\u2014can lead to a breakdown, with a consequent, signi\ufb01cant economic loss; wind turbines provide an excellent example. Embedded solutions are therefore required to monitor the insulation status. The paper presents an online system that adopts unsupervised methodologies for assessing the condition of the monitored machine in real time. The monitoring process does not rely on any prior knowledge about the apparatus; nonetheless, the method can identify the relevant drifts in the machine status. In addition, the system is speci\ufb01cally designed to run on low-cost embedded devices

Abstracts of the Second Urban Sound Symposium

Following the successful first Urban Sound Symposium held at Ghent University in 2019, the second edition in 2021 had to face the challenges of the pandemic. The symposium turned this challenge into an opportunity for giving easier access to practitioners and experts from around the globe who are confronted with urban sound in their professional activities. It was organized simultaneously in Ghent, Montreal, Nantes, Zurich, London and Berlin by researchers at Ghent University, Mc Gill University, Université Gustave Eiffel, EMPA, University College London and TU Berlin. The online event created opportunities for interaction between participants at poster-booths, virtual coffee tables, and included social activities

Flare forecasting and feature ranking using SDO/HMI data

We describe here the application of a machine learning method for flare forecasting using vectors of properties extracted from images provided by the Helioseismic and Magnetic Imager in the Solar Dynamics Observatory (SDO/HMI). We also discuss how the method can be used to quantitatively assess the impact of such properties on the prediction process

Active Learning for Auditory Hierarchy

Much audio content today is rendered as a static stereo mix: fundamentally a fixed single entity. Object-based audio envisages the delivery of sound content using a collection of individual sound ‘objects’ controlled by accompanying metadata. This offers potential for audio to be delivered in a dynamic manner providing enhanced audio for consumers. One example of such treatment is the concept of applying varying levels of data compression to sound objects thereby reducing the volume of data to be transmitted in limited bandwidth situations. This application motivates the ability to accurately classify objects in terms of their ‘hierarchy’. That is, whether or not an object is a foreground sound, which should be reproduced at full quality if possible, or a background sound, which can be heavily compressed without causing a deterioration in the listening experience. Lack of suitably labelled data is an acknowledged problem in the domain. Active Learning is a method that can greatly reduce the manual effort required to label a large corpus by identifying the most effective instances to train a model to high accuracy levels. This paper compares a number of Active Learning methods to investigate which is most effective in the context of a hierarchical labelling task on an audio dataset. Results show that the number of manual labels required can be reduced to 1.7% of the total dataset while still retaining high prediction accuracy

Soundscape assessment: Towards a validated translation of perceptual attributes in different languages

The recently published ISO/TS 12913-2:2018 standard aims to provide researchers and practitioners around the world with a reliable questionnaire for soundscape characterization. The ISO Technical Specifications report protocols and attributes grounded in the soundscape literature, but only includes an English version. The applicability and reliability of these attributes in non-English speaking regions remains an open question, as research investigating translations of soundscape attributes is limited. To address this gap, an international collaboration was initiated with soundscape researchers from all over the world. Translation into 15 different languages, obtained through focus groups and panels of experts in soundscape studies, are proposed. The main challenges and outcomes of this preliminary exercise are discussed. The long-term objective is to validate the proposed translations using standardized listening experiments in different languages and geographical regions as a way to promote a widespread use of the soundscape attributes, both in academia and practice, across locations, populations and languages

Mind-wandering and alterations to default mode network connectivity when listening to naturalistic versus artificial sounds

Naturalistic environments have been demonstrated to promote relaxation and wellbeing. We assess opposing theoretical accounts for these effects through investigation of autonomic arousal and alterations of activation and functional connectivity within the default mode network (DMN) of the brain while participants listened to sounds from artificial and natural environments. We found no evidence for increased DMN activity in the naturalistic compared to artificial or control condition, however, seed based functional connectivity showed a shift from anterior to posterior midline functional coupling in the naturalistic condition. These changes were accompanied by an increase in peak high frequency heart rate variability, indicating an increase in parasympathetic activity in the naturalistic condition in line with the Stress Recovery Theory of nature exposure. Changes in heart rate and the peak high frequency were correlated with baseline functional connectivity within the DMN and baseline parasympathetic tone respectively, highlighting the importance of individual neural and autonomic differences in the response to nature exposure. Our findings may help explain reported health benefits of exposure to natural environments, through identification of alterations to autonomic activity and functional coupling within the DMN when listening to naturalistic sounds