This proceedings volume highlights the role and importance of Operational Research (OR) in the digital era and the underlying ICT challenges. The selected papers cover recent advances in all branches of operational research, mathematical modeling and decision making. It covers a wide range of key areas from digital economy, to supply chain management, and also finance. The book adopts an applied perspective that covers the contributions of OR in the broad field of business and economics linked with the discipline of computer science. The chapters are based on papers presented at the 6th International Symposium & 28th National Conference on Operational Research. Although the conference is organized by the Hellenic Operational Research Society (HELORS), the contributions in this book promotes international co-operation among researchers and practitioners working in the field.

This book provides a comprehensive and practical introduction to Data Envelopment Analysis (DEA). It explains how this non-parametric technique is used to measure performance and extract efficiency from homogeneous entities within a production procedure. It situates DEA within a growing field of productivity analysis and performance measurement, for which numerous models have been proposed.  This book encapsulates all of the advances in DEA models proposed in the literature. These models are presented in the context of the GAMS software, which is a powerful tool for mathematical programming models. This book serves two educational purposes: it introduces readers to DEA models and provides examples using GAMS. In addition, the reader is introduced to GAMS programming, as well as innovative and practical applications. GAMS codes are available for free, allowing readers to test and expand the models to meet their specific needs.

This proceedings volume highlights the role and importance of Operational Research (OR) in the digital era and the underlying ICT challenges. The selected papers cover recent advances in all branches of operational research, mathematical modeling and decision making. It covers a wide range of key areas from digital economy, to supply chain management, and also finance. The book adopts an applied perspective that covers the contributions of OR in the broad field of business and economics linked with the discipline of computer science. The chapters are based on papers presented at the 6th International Symposium & 28th National Conference on Operational Research. Although the conference is organized by the Hellenic Operational Research Society (HELORS), the contributions in this book promotes international co-operation among researchers and practitioners working in the field.