This book constitutes the proceedings of the 19th Russian Conference on Artificial Intelligence, RCAI 2021, held in Moscow, Russia, in October 2021.The 19 full papers and 7 short papers presented in this volume were carefully reviewed and selected from 80 submissions.

Cognitive Research.- Heterogeneous Formal Neurons and Modeling of Multi-Transmitter Neural Ensembles.- Methods for Recognition of Frustration-Derived Reactions in Social Media.- Identification of the Network State Based on the ART-2 Neural Network with a Hierarchical Memory Structure in Parallel Mode.- Data Mining, Machine Learning, Classification.-  Ranking Weibull Survival Model: Boosting Concordance Index of Weibull Time-to-event Prediction Model with Ranking Losses.- Predicting Different Health and Lifestyle Behaviors of Social Media Users.- Methods for Finding Consequences with Specified Properties.- Data Mining Methods for Analysis and Forecast of Emerging Technology Trend: A Systematic Mapping Study from SCOPUS Papers.- Machine Learning for Assessment of Cardiometabolic Risk Factors Predictive Potential and Prediction of Obstructive Coronary Arteries Lesions.- Knowledge Engineering.- Application of FCA for Domain Model Theory Investigation.- The Metagraph Model for Complex Networks: Definition, Calculus and Granulation Issues.- Subjective Expert Evaluations in the Model-Theoretic Representation of Object Domain Knowledge.- Multiagent Systems and Robotics.- Q-Mixing Network for Multi-Agent Path Finding in Partially Observable Grid Environments.- Subdefinite Computations for Reducing the Search Space in Mobile Robot Localization Task.- Enhancing Exploration Algorithms for Navigation with Visual SLAM.- Natural Language Processing.- Relying on Discourse Trees to Extract Medical Ontologies from Text.- TITANIS: A Tool for Intelligent Text Analysis in Social Media.- Approach to the Automated Development of Scientific Subject Domain Ontologies Based on Heterogeneous Ontology Design Patterns.- Fuzzy Models and Soft Computing.- PC-algorithm of Algebraic Bayesian Network Secondary Structure Training.- Logistic-based Design of Fuzzy Interpretable Classifiers.- Intelligent Systems.- Knowledge-Based Diagnostic Systemwith a Precedent Library.- Semiotic Models in Monitoring and Decision Support Systems.- Cognitive Patterns for Semantic Presentation of Natural-language Descriptions of Well-formalizable Problems.- Detecting Anomalous Behavior of Users of Data Centers based on the Application of Artificial Neural Networks.- Tools for Designing Intelligent Systems.- Study of the Feasibility of Creating of a Real-time Neuronetwork Infrared Ground Objects Recognition System.- The Implementation of the Ontological Approach to Control of the Processes of Designing Integrated Expert Systems Based on the Problem-oriented Methodology.- A Module for Industrial Safety Inspection Planning Based on Self-organization.-