1,505 research outputs found
Screening Polarimetric SAR Data via Geometric Barycenters for Covariance Symmetry Classification
This letter proposes a robust framework for polarimetric covariance symmetries classification in Synthetic Aperture Radar (SAR) images applying a pre-screening on the data looks before they are used to perform inferences. More specifically, the devised method improves the performance of a previous work based on the exploitation of the special structures assumed by the covariance/coherence matrix when symmetric scattering mechanisms dominate the polarimetric returns. To do this, the algorithm selects first the most homogeneous data through the cancellation of those sharing the highest Generalized Inner Product (GIP) values computed with the use of the geometric barycenters. Then, the procedure based on Model Order Selection (MOS) developed in the homogeneous case is applied on the filtered data. The conducted tests show the potentiality of the proposed method in correctly classifying the observed scene of L-band real-recorded SAR data with respect to its standard counterpart
Quantum physics at high school: a collaboration between physics researchers and teachers to design teaching - learning sequences
Quantum physics is changing the paradigms for understanding reality and is fostering scientific innovation. Nevertheless, the core concepts of the second quantum revolution are not included in the Italian physics curriculum. Our research project aims to generate the conditions for the development of the scientific competences related to the understanding of the fundamental concepts of contemporary physics at secondary school level. In the framework of Educational Reconstruction for Teacher Education (ERTE), we have developed a continuous professional development program for teachers to enable in-service physics teachers in secondary schools to introduce the superposition principle, quantum entanglement, and their technological applications into regular classroom activities. To achieve this goal, several types of activities have been planned to strengthen collaboration between high school teachers and physics researchers. The intended outcome is to create resources and materials that can help teachers and researchers create innovative physics curricula that can be used in normal secondary school teaching activities. In this paper we present the results of the first edition of a continuous professional development program for in-service teachers on introducing the superposition principle and quantum entanglement into online classroom activities during the schools Covid19 lockdown
A Machine Learning-Based Approach for Audio Signals Classification using Chebychev Moments and Mel-Coefficients
This paper proposes a machine learning-based architecture for audio signals classification based on a joint exploitation of the Chebychev moments and the Mel-Frequency Cepstrum Coefficients. The procedure starts with the computation of the Mel-spectrogram of the recorded audio signals; then, Chebychev moments are obtained projecting the Cadence Frequency Diagram derived from the Mel-spectrogram into the base of Chebychev moments. These moments are then concatenated with the Mel-Frequency Cepstrum Coefficients to form the final feature vector. By doing so, the architecture exploits the peculiarities of the discrete Chebychev moments such as their symmetry characteristics. The effectiveness of the procedure is assessed on two challenging datasets, UrbanSound8K and ESC-50
Meteorologia aplicada ao esporte: um estudo de caso
Increasing interests in a better knowledge about how several influences of weather and climate on human's life and their activities lead this work to study the meteorology applied to sports. This paper presents a detailed analysis about the meteorological service performance on the 52° World Championships of Modern Pentathlon, since the job routine description during the competition until the validation of the forecasts released to the community (athlets, coachs, organization committee and audience), taking into account the data collected in competition site. As conclusions, was verified that a specific service like this one is really necessary in a competitive sports environment, and that the forecasts had a satisfactory role on the support for the best performance of the athlet
Changes in the composition of the passive layer and pitting corrosion of stainless steel in phosphate-borate buffer containing chloride ions
The influence of the passive layer properties on the pitting corrosion of 316SS was studied in phosphate—borate buffer containing chloride ions by using potential step and potentiodynamic techniques complemented with scanning electron microscopy. The increase of the anodization time in the passive region decreases the nucleation rate and the mean number of corrosion pits formed onthe 316SS surface. Results are explained through changes in the structure and composition of the passive layer during anodization. Two different Cr(III) species can be voltammetrically detected at short anodization times, an outer weakly bound Cr(III) species which is electroaoxidized to soluble CrO42− and an inner Cr(III) species which is electrooxidized to Cr(VI) but retained in the film at potentials lying in the transpassive region. As the anodization time in the passive region increases, the weakly bound Cr(III) species is transformed into another more stable one, probably an iron chromite, which exhibits an electooxidation potential more positive than that of Cr(III) species. The aged passive layer becomes more resistant to pit initiation, due to either a decrease in the density of active sites or a decrease in the nucleation rate constant for pit initiation.Instituto de Investigaciones FisicoquÃmicas Teóricas y Aplicada
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