Yılmaz, Selim Fırat2021-08-042021-08-042021-072021-072021-07-30http://hdl.handle.net/11693/76402Cataloged from PDF version of article.Thesis (Master's): Bilkent University, Department of Electrical and Electronics Engineering, İhsan Doğramacı Bilkent University, 2021.Includes bibliographical references (leaves 46-52).We investigate unsupervised anomaly detection for high-dimensional data and introduce a deep metric learning (DML) based framework. In particular, we learn a distance metric through a deep neural network. Through this metric, we project the data into the metric space that better separates the anomalies from the normal data and reduces the effect of the curse of dimensionality for high-dimensional data. We present a novel data distillation method through self-supervision to remedy the conventional practice of assuming all data as normal. We also employ the hard mining technique from the DML literature. We show these components improve the performance of our model. Through an extensive set of experiments on the 14 real-world datasets, our method demonstrates significant performance gains compared to the state-of-the-art unsupervised anomaly detection methods, e.g., an absolute improvement between 4.44% and 11.74% on the average over the 14 datasets. Furthermore, we share the source code of our method on Github to facilitate further research.ix, 52 leaves : charts ; 30 cm.Englishinfo:eu-repo/semantics/openAccessAnomaly detectionUnsupervisedOne-classDeep metric learningData distillationThesisB157322