Principal component analysis color augmentation (PCA) and perturbations of saturation-value (SV) of the hue-saturation-value (HSV) color scale achieved a PR AUC of 0.779 ± 045 and 0.784 ± 0.037, respectively. Among the single data augmentation techniques explored, horizontal flipping of the spectrogram image improved the model performance the most, with a PR AUC of 0.819 ± 0.044. The baseline control model achieved a PR AUC of 0.763 ± 0.047. We built a standard CNN model to classify cardiac sound recordings as either normal or abnormal. To that end, we examined a CNN model’s performance on automated heart sound classification, before and after various forms of data augmentation, and aimed to identify the most optimal augmentation methods for cardiac spectrogram analysis. However, the relative paucity of patient data remains a significant barrier to creating models that can adapt to a wide range of potential variability. The use of convolutional neural networks (CNN) on heart sound spectrograms in particular has defined state-of-the-art performance. "For instance, the frequency of the bursts, and how they change as the source moves away from Earth, could be used to measure the rate at which the universe is expanding," the press release reads.The application of machine learning to cardiac auscultation has the potential to improve the accuracy and efficiency of both routine and point-of-care screenings. More periodic signals from this source could be used as an astrophysical clock. "Future telescopes promise to discover thousands of FRBs a month, and at that point we may find many more of these periodic signals." "This detection raises the question of what could cause this extreme signal that we've never seen before, and how can we use this signal to study the universe," said Michilli. The detection could help them as they study the universe and neutron stars. They hope to catch more bursts from FRB 20191221A. From the properties of this new signal, we can say that around this source, there's a cloud of plasma that must be extremely turbulent." "We've seen some that live inside clouds that are very turbulent, while others look like they're in clean environments. "CHIME has now detected many FRBs with different properties," said Michilli.
These are dense, rapidly spinning collapsed cores of giant stars. The source of the new FRB remains a mystery, but scientists think it could emanate from a radio pulsar or magnetar, which are neutron stars. It is currently the longest-lasting FRB with the clearest periodic pattern detected to date. Researchers from MIT and McGill University in Canada, who published a study on the signal, have named it FRB 20191221A. The signal came from a distant galaxy, several billion light-years from Earth. Photo courtesy of CHIME, with background edited by MIT News Pictured is the large radio telescope CHIME that picked up the FRB. Named FRB 20191221A, this fast radio burst, or FRB, is currently the longest-lasting FRB, with the clearest periodic pattern, detected to date. This is the first time the signal itself is periodic." Astronomers detected a persistent radio signal from a far-off galaxy that appears to flash with surprising regularity. "Not only was it very long, lasting about three seconds, but there were periodic peaks that were remarkably precise, emitting every fraction of a second - boom, boom, boom - like a heartbeat. "It was unusual," said Daniele Michilli, a postdoc in MIT's Kavli Institute for Astrophysics and Space Research.