Both the editors of this book were exposed to human-in-the-loop simulations while pursuing their doctoral degrees in the Center for Human-Machine Systems at Georgia Tech. In fact, S. Narayanan served as Ling Rothrock’s teaching assistant for the simulation course taught by Prof. Christine Mitchell. It has been over 15 years since our Georgia Tech days and we have both been continuously active in human-in-the-loop simulation research. The purpose of this book is to leverage the lessons we learned to provide researchers and teachers with a handbook on how human-in-the-loop simulations can be used to study human interactions in various contexts.

A human-in-the-loop (HITL) simulation is a modeling framework that requires human interaction. Traditional simulation studies regard human interaction as an external input to the system being considered. However, studies of complex systems in today’s technological landscape must include humans as active participants. For example, a study of highly automated call centers must include human judgement and decision making and the accompanying task context. The emergence of HITL technologies, therefore, enables researchers and practitioners to investigate the complexities of human-involved interactions from a holistic, systems perspective. The handbook consists of contributed chapters from experts in academia and industry in the area of human-in-the-loop simulation. By reading it, the reader should gain an understanding of what an HITL simulation is and how it differs from traditional simulations, an appreciation for how HITL simulations can be used to study human involvement in complex systems, and an understanding of the current research thrusts involving HITL simulations.

Human-in-the-Loop Simulations is a compilation of articles from experts in the design, development, and use of human-in-the-loop simulations. The first section of the handbook consists of papers on fundamental concepts in human-in-the-loop simulations, such as object-oriented simulation development, interface design and development, and performance measurement. The second section includes papers from researchers who utilized HITL simulations to inform models of cognitive processes to include decision making and metacognition. The last section describes human-in-the-loop processes for complex simulation models in trade space exploration and epidemiological analyses. Human-in-the-Loop Simulations is a useful tool for multiple audiences, including graduate students and researchers in engineering and computer science.