A comprehensive theoretical framework for the optimization of neural networks classification performance with respect to weighted metrics

In many contexts, customized and weighted classification scores are designed in order to evaluate the goodness of the predictions carried out by neural networks. However, there exists a discrepancy between the maximization of such scores and the minimization of the loss function in the training phase. In this paper, we provide a complete theoretical setting that formalizes weighted classification metrics and then allows the construction of losses that drive the model to optimize these metrics of interest. After a detailed theoretical analysis, we show that our framework includes as particular instances well-established approaches such as classical cost-sensitive learning, weighted cross entropy loss functions and value-weighted skill scores

Partial Discharge alert system in medium voltage switchgear

Partial discharge (PD) is a well-known indicator of insulation problems in high voltage equipment. We report on experience collected during the development of a new online PD detection and alert system for air insulated switchgear (AIS) installed base. The approach taken to integrate the sensor with minimal retrofit effort and operational disruption is described. Results from a test setup including a line-up of panels and different reference PD sources in comparison to a commercial PD system are presented. The effect of cables connected to the switchgear is investigated by testing the system including additional capacitive load and using a simulation for a typical geometry. We also address the question regarding the design of an alert system to be used in connection with the continuous data acquisition

AI-FLARES: Artificial Intelligence for the Analysis of Solar Flares Data

AI-FLARES (Artificial Intelligence for the Analysis of Solar Flares Data) is a research project funded by the Agenzia Spaziale Italiana and by the Istituto Nazionale di Astrofisica within the framework of the ``Attivit\`a di Studio per la Comunit\`a Scientifica Nazionale Sole, Sistema Solare ed Esopianeti'' program. The topic addressed by this project was the development and use of computational methods for the analysis of remote sensing space data associated to solar flare emission. This paper overviews the main results obtained by the project, with specific focus on solar flare forecasting, reconstruction of morphologies of the flaring sources, and interpretation of acceleration mechanisms triggered by solar flares

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

Soundscape descriptors and a conceptual framework for developing predictive soundscape models

Soundscape exists through human perception of the acoustic environment. This paper investigates how soundscape currently is assessed and measured. It reviews and analyzes the main soundscape descriptors in the soundscape literature, and provides a conceptual framework for developing predictive models in soundscape studies. A predictive soundscape model provides a means of predicting the value of a soundscape descriptor, and the blueprint for how to design soundscape. It is the key for implementing the soundscape approach in urban planning and design. The challenge is to select the appropriate soundscape descriptor and to identify its predictors. The majority of available soundscape descriptors are converging towards a 2-dimensional soundscape model of perceived affective quality (e.g., Pleasantness–Eventfulness, or Calmness–Vibrancy). A third potential dimension is the appropriateness of a soundscape to a place. This dimensions provides complementary information beyond the perceived affective quality. However, it depends largely on context, and because a soundscape may be appropriate to a place although it is poor, this descriptor must probably not be used on its own. With regards to predictors, or soundscape indicators, perceived properties of the acoustic environment (e.g., perceived sound sources) are winning over established acoustic and psychoacoustic metrics. To move this area forward it is necessary that the international soundscape community comes together and agrees on relevant soundscape descriptors. This includes to agree on numerical scales and assessment procedures, as well as to standardize them

Combined Electrical and Thermal Stress on Twisted Pairs: Study of the Variation over Time of the Partial Discharges Inception Voltage

The electrical insulation of small power electrical machines is a critical element especially when they are powered by means of electronic power supplies using techniques such as PWM. Power supplies based upon pulsed voltage trains can introduce, under certain conditions, overvoltage and this overvoltage can produce the inception of partial discharge phenomena. Enameled wires, even in case of high insulating thermal classes, cannot resist for a long time to the erosive action of the partial discharges and therefore, inevitably, reaching the total discharge conditions. In addition, the erosion of the enamel causes a decrease of the inception voltage, aggravating the situation and quickly leading to the total breakdown. In this study enameled wires thermal class W-240 °C have been considered. These wires have been used to prepare twisted-pair specimen following the IEC 60851-5 standard. They have been subjected to thermo-electric ageing using a sinusoidal test voltage waveform, varying its amplitude and frequency. The obtained results show that, during the degradation, the PDIV values continuously decrease following an inverse power law relationship. Furthermore, the obtained data evidence that the PDIV derivatives do not depend on the test voltage amplitudes and frequencies but rather seems to depend on the temperatur