Ilya Trofimov is a Principal Data Scientist in Yandex, Moscow. He graduated from Moscow State University. Ilya has 7 years’ experience of solving practical data science problem of online advertising, e-commerce and recommender systems. Ilya has 6 publications in peer-reviewed international journals and conferences. For last 4 years Ilya gives lectures on large-scale machine learning in Yandex School of Data Analysis and Moscow Institute of Physics and Technology.