**Aggregation Functions: A Guide for Practitioners** This book provides a practical guide for computer scientists, system architects, knowledge engineers, and programmers who need to combine various inputs into a single output. It focuses on aggregation functions, which combine numerical inputs into a single output, and discusses how to choose or construct these functions for specific applications. The book introduces key concepts such as means, ordered weighted averaging (OWA) functions, Choquet integrals, triangular norms and conorms, uninorms, and nullnorms. It explains the properties and applications of these functions, and provides methods for constructing them from empirical data. The book also covers advanced topics such as interpolation and approximation techniques, and presents various state-of-the-art methods. The book is structured into chapters that discuss different types of aggregation functions, their properties, and how to choose or construct them. It includes examples of computer code in C++ for calculating the value of an aggregation function, as well as generalizations and advanced constructions. The book also provides a software package, AOTool, which allows users to fit aggregation functions to empirical data and visualize them. The book is aimed at practitioners who need to apply aggregation functions in real-world applications. It provides a clear and concise introduction to the subject, with a focus on practical applications and real-world examples. The book is written in a way that is accessible to readers without a strong mathematical background, and includes a variety of examples and tools to help readers implement aggregation functions in practice.**Aggregation Functions: A Guide for Practitioners** This book provides a practical guide for computer scientists, system architects, knowledge engineers, and programmers who need to combine various inputs into a single output. It focuses on aggregation functions, which combine numerical inputs into a single output, and discusses how to choose or construct these functions for specific applications. The book introduces key concepts such as means, ordered weighted averaging (OWA) functions, Choquet integrals, triangular norms and conorms, uninorms, and nullnorms. It explains the properties and applications of these functions, and provides methods for constructing them from empirical data. The book also covers advanced topics such as interpolation and approximation techniques, and presents various state-of-the-art methods. The book is structured into chapters that discuss different types of aggregation functions, their properties, and how to choose or construct them. It includes examples of computer code in C++ for calculating the value of an aggregation function, as well as generalizations and advanced constructions. The book also provides a software package, AOTool, which allows users to fit aggregation functions to empirical data and visualize them. The book is aimed at practitioners who need to apply aggregation functions in real-world applications. It provides a clear and concise introduction to the subject, with a focus on practical applications and real-world examples. The book is written in a way that is accessible to readers without a strong mathematical background, and includes a variety of examples and tools to help readers implement aggregation functions in practice.