The University of Crete, Greece, ITMO University and Lomonosov Moscow State University, Russia supported by the Foundation for Research and Technology - Hellas (FORTH), Greece, National Center for Cognitive Research, and Center for Big Data Analysis, Russia, announce 2020 International Young Scientists Conference and Intensive Training School for Big Data vs. Simulation for young researchers and professionals in computational science to take place at University of Crete, Heraklion, Greece.Simulation and systems thinking is one way to explain the complex world in which we live. By collecting big data and building computer models, scientists can make predictions or even preventions on critical situations. The Conference aims to strengthen the ties between young scientists in different countries, thus promoting future collaboration in the framework of Computational Science and major application aspects of big data, high performance computing, computer modeling and simulation to tackle a wide range of issues in science, industry and business. Special topics of the conference will include also the cognitive models, such as opinion dynamics, media science, data mining of social web as well as sentiment analysis.Additionally, the Conference includes the Intensive Training School on Big Data which aims to train participants by means of best practices in data operations, analytics and building of models.