This book contains selected papers from the KES-IDT-2021 conference, being held as a virtual conference in June 14-16, 2021. 

The KES-IDT is an interdisciplinary conference with opportunities for the presentation of new research results and discussion about them under the common title "Intelligent Decision Technologies". The conference has been creating for years a platform for knowledge transfer and the generation of new ideas in the field of intelligent decision making.

The range of topics discussed during the conference covered methods of classification, prediction, data analysis, big data, decision support, knowledge engineering, modeling, social networks and many more in areas such as finance, economy, management and transportation. The discussed topics covered also decision making for problems regarding the electric vehicle industry.

The book contains also several sections devoted to specific topics, such as

• Advances in intelligent data processing and its applications
• Multi-criteria decision analysis methods
• Knowledge engineering in large-scale systems
• High-dimensional data analysis
• Spatial data analysis and sparse estimation
• Innovative technologies and applications in computer intelligence
• Intelligent diagnosis and monitoring of systems
• Decision making theory for economics.