Cities have always played a prominent role in the prosperity of civilization. Indeed every
great civilization we can think of is associated with the prominence of one or more thriving
cities. And so understanding cities -- their inhabitants their institutions their
infrastructure -- what they are and how they work independently and together -- is of
fundamental importance to our collective growth as a human civilization. Furthermore the 21st
century smart city as a result global climate change and large-scale urbanization will emerge
as a societal grand challenge. This book focuses on the role of interdependent infrastructure
systems in such smart cities especially as it relates to timely and poignant questions about
resilience and sustainability. In particular the goal of this book is to present in one
volume a consistent Hetero-Functional Graph Theoretic (HFGT) treatment of interdependent smart
city infrastructures as an overarching application domain of engineering systems. This work may
be contrasted to the growing literature on multi-layer networks which despite significant
theoretical advances in recent years has modeling limitations that prevent their real-world
application to interdependent smart city infrastructures of arbitrary topology. In contrast
this book demonstrates that HFGT can be applied extensibly to an arbitrary number of
arbitrarily connected topologies of interdependent smart city infrastructures. It also
integrates for the first time all six matrices of HFGT in a single system adjacency matrix.
The book makes every effort to be accessible to a broad audience of infrastructure system
practitioners and researchers (e.g. electric power system planners transportation engineers
and hydrologists etc.). Consequently the book has extensively visualized the graph theoretic
concepts for greater intuition and clarity. Nevertheless the book does require a common
methodological base of its readers and directs itself to the Model-Based Systems Engineering
(MBSE) community and the Network Science Community (NSC). To the MBSE community we hope that
HFGT will be accepted as a quantification of many of the structural concepts found in
model-based systems engineering languages like SysML. To the NSC we hope to present a new view
as how to construct graphs with fundamentally different meaning and insight. Finally it is our
hope that HFGT serves to overcome many of the theoretical and modeling limitations that have
hindered our ability to systematically understand the structure and function of smart cities.
