Preface

The treatment of systems using fuzzy logic has developed in recent decades, with this mathematical theory being an interesting tool for researchers to solve complex scientific and technical problems. Fuzzy systems have found applications in various sectors of human activity, such as industry, business, finance, medicine, and more. A fuzzy system architecture is built on four concepts: fuzzification, knowledge base, inference, and defuzzification. Fuzzy logic allows for a systemic mathematical treatment using acceptable human reasoning. The fuzzy systems thus developed can in turn deal with the uncertainties in real applications.

The book addresses specialists who are interested in applications of fuzzy systems. It covers some fuzzy theoretical concepts and includes new methodologies and applications of fuzzy systems. Published studies demonstrate the ability of fuzzy systems in various practical fields. Researchers in different domains have developed new fuzzy concepts, applications, and tools that enhance human understanding and improve the specialist's ability to analyze, design, and implement high-performance algorithms. The book presents applications that focus on the methodologies used, with case studies as well as implementation and testing issues.

The book includes eight sections: "Fuzzy Mathematics"; "Decision Making"; "Clustering"; "Adaptive Neural Fuzzy Inference Systems"; "Process Monitoring"; "Control Systems"; "Green Infrastructure"; and "Applications in Medicine." These sections include fifteen chapters that illustrate the research in the abovementioned domains. Section 1 includes four chapters that present theoretical studies on the solutions of fuzzy fractional differential equations, Pythagorean fuzzy descriptor systems, fuzzy sequence spaces, and context logic as an extension of fuzzy logic. Section 2 contains two theoretical studies about dual hesitant fuzzy sets and their application to multi-attribute decision making and the application of intuitionistic fuzzy sets to evaluate employee performance. Section 3 contains a theoretical study on data clustering for fuzzifier value derivation. Section 4 contains a study to improve characteristics of ANFIS with application in robotics. Section 5 contains two chapters on health monitoring of power transformers and aircraft fuel systems. Section 6 contains two theoretical studies on fuzzy logic controller with particle swarm optimization tuning and the use of fuzzy logic in the control of solar energy installations. Section 7 contains two studies on the application of Zadeh's Z-numbers to the location of smoke towers and on the fuzzy modelling of urban water supply crisis. Section 8 contains a chapter addressing the application of fuzzy logic in the diagnosis of human diseases.

The editor thanks the contributing authors as well as the staff at IntechOpen, especially Author Service Manager Kristina Kardum Cvitan.

> **Constantin Voloşencu** Department of Automation and Applied Informatics, "Politehnica" University Timişoara, Timişoara, Romania
