Patent EP-3719711-A2 (EP)
Inventor: MALAGO LUIGI
IPC: G06N3/08
Filed: 2020-07-30
Abstract: This patent refers to a computer-implemented method for detecting anomalous data in a test dataset using two Variational AutoEncoders VAEs by means of using a machine-computing unit, the method comprising training and validation steps as well as testing steps. 
     In the training and validation steps a first Variational AutoEncoder VAE model (VAE-H) is trained on a first plurality of data cases from a first dataset H corresponding to non-anomalous data cases, whereas a second Variational AutoEncoder VAE model (VAE-U) is trained on a second plurality of data cases from a second dataset U as a mix of unlabelled data with and without anomalies, such that it learns variegated representations of data cases with and without anomalies. 
     A first plurality of dissimilarity measures is computed between a first encoding of the data case through the second Variational AutoEncoder model (VAE-U) and a second encoding of the reconstructed data case through the second Variational AutoEncoder model (VAE-U) for the data cases of the first plurality, then a first anomaly threshold is computed based on said first plurality of dissimilarity measures. 
     In the testing steps, the anomalous data is detected in the test dataset comprising at least one raw data case by computing a dissimilarity measure between the first encoding of the raw data case through the second Variational AutoEncoder model (VAE-U) and the second encoding of the reconstruction of the raw data case through the second Variational AutoEncoder model (VAE-U) and comparing the dissimilarity measure with the first anomaly threshold. If the dissimilarity measure is greater than the first anomaly threshold the raw data case is labelled as anomalous and an anomaly mask is determined for localizing the anomaly in the data case. The anomalous data cases and their localization are made accessible to a decision maker. 
     The patent also discloses a machine computing unit for carrying out the method, a computer program to be executed by the machine computing unit, a computer readable medium and a data stream. 
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