This book is composed of selected papers presented at IWIFSGN'2019-The Eighteenth International Workshop on Intuitionistic Fuzzy Sets and Generalized Nets-held on October 24-25, 2019, in Warsaw, Poland, which is one of the main conferences on fuzzy logic, notably on extensions of the traditional fuzzy sets, in particular on the intuitionistic fuzzy sets. A considerable part of the conference sessions is also concerned with recent developments and challenges in the theory and applications of other topics exemplified by uncertainty, incompleteness and imprecision modeling, the Generalized Nets (GNs), a powerful extension of the traditional Petri net paradigm, and the InterCriteria Analysis, a new method for the feature selection and analyses in multicriteria and multiattribute decision-making problems. Some more general problems of computational and artificial intelligence, exemplified by evolutionary computations, machine learning, etc., are also dealt with. The papers included yield a good perspective on all of these important issues and problems.

This book gathers selected papers from two important conferences held on October 24-28, 2018, in Warsaw, Poland: theFifteenth National Conference of Operational and Systems Research, BOS-2018, one of the leading conferences in the field of operational and systems research not only in Poland but also at the European level; andthe Seventeenth International Workshop on Intuitionistic Fuzzy Sets and General Nets, IWIFSGN-2018, one of thepremiere conferences on fuzzy logic. The papers presented here constitute a fair and comprehensive representation of the topics covered by both BOS-2018 and IWIFSGN-2018, includingextensions of the traditional fuzzy sets, in particular on the intuitionistic fuzzy sets, as well as other topics in uncertainty and imprecision modeling, the Generalized Nets (GNs), a powerful extension of the traditional Petri net paradigm, and InterCriteria Analysis, a new method for feature selection and analyses in multicriteria and multi-attribute decision-making problems. The Workshop was dedicated to the memory of Professor Beloslav Riecan (1936-2018), a regular participant at the IWIFSGN workshops.

This book presents selected papers from two important conferences held on October 12-14, 2016 in Warsaw, Poland: the Fourteenth National Conference of Operational and Systems Research, BOS-2016, one of the premiere conferences in the field of operational and systems research not only in Poland but also at the European level; and the Fifteenth International Workshop on Intuitionistic Fuzzy Sets and General Nets, IWIFSGN-2016, one of the foremost conferences on fuzzy logic, notably addressing extensions of the traditional fuzzy sets, as well as the Generalized Nets (GNs), a powerful extension of the traditional Petri net paradigm. The scope of the BOS con ferences includes all types of problems related to systems modeling, systems analysis, broadly perceived operational research, optimization, decision making, and decision support, to name but a few. In all these areas, virtually all models used have to take into account not only uncertainty in its traditional sense, but also imprecision of information. That is, in addition to traditional probabilistic and statistical tools and techniques, the use of methods based on fuzzy sets can also be sensible. Even more so, employing certain extensions of the classic concept of a fuzzy set can be very useful. Applying intuitionistic fuzzy sets, which are at the core of the IWIFSGN conferences, is a good example. Both conferences, BOS-2016 and IWIFSGN-2016, offered ideal venues for the exchange of ideas, cross-fertilization, and mutual inspiration.

This book is composed of selected papers from the Sixteenth National Conference on Operational and Systems Research, BOS-2020, held on December 14-15, 2020, one of premiere conferences in the field of operational and systems research. The second is the Nineteenth International Workshop on Intuitionistic Fuzzy Sets and Generalized Nets, IWIFSGN 2020, held on December 10-11, 2020, in Warsaw, Poland, in turn-one of premiere conferences on fuzzy logic, notably on extensions of the traditional fuzzy sets, also comprising a considerable part on the generalized nets (GNs), an important extension of the traditional Petri nets. A joint publication of selected papers from the two conferences follows a long tradition of such a joint organization and-from a substantial point of view-combines systems modeling, systems analysis, broadly perceived operational research, notably optimization, decision making, and decision support, with various aspects of uncertain and imprecise information and their related tools and techniques.