ANC Seminar - 02/11/21
Speaker: Sibylle Hess
Title: Optimization with binary constraints: from k-means to deep learning
In the field of data mining, there is one big open problem: the optimization subject to binary constraints. Binary constraints are ubiquitous in data mining tasks. They make results interpretable and definite. Is this picture showing a cat? Should this movie be recommended to this user? Should the next chess move be this one? Binary results give a definite answer to questions like these. There are a lot of methods which are able to solve binary constrained problems, however, they mostly work under one condition: exclusivity. That is, if a picture shows a cat, then it can not show a dog, if a movie is recommended to one user, then it can't be recommended to the other, and there should only be one next chess move which is the optimal one. Depending on the application, this assumption is is more or less justified. The field of clustering is an area in which the optimization subject to binary constraints is explicitly studied. In this talk, we will discuss the broad spectrum of tasks where a matrix factorization approximation error in Frobenius norm is minimized subject to binary constraints. We will unveil under which circumstances this optimization task defines the clustering objectives of k-means, spectral clustering and subspace clustering, but we will also make connections to other methods such as deep learning classifiers. Furthermore, I will present my work on a gradient-descent based approach to tackle the general clustering problem of optimizing a smooth loss function subject to binary constraints, dropping the assumption of exclusivity.
Sibylle Hess is assistant professor of data mining at TU Eindhoven. She completed her Ph.D. summa cum laude in 2019 at Katharina Morik's lab at TU Dortmund University, Germany, as an employee of the collaborative research center SFB876. Sibylle investigated in her thesis the derivation of (certifiably) robust clustering methods under the framework of matrix factorizations. She has been a PC member of various conferences, such as Neurips, ICML, ICLR, KDD, ECML-PKDD, UAI, AISTATS and ICDM and received a top-reviewer award at ICML 2020. Since 2020, she is teaching two Bachelor courses on Data Mining per year.
ANC Seminar - 02/11/21