  System-of-systems (SoS) approach is often used for simulating disruptions to
business and infrastructure system networks allowing for integration of several
models into one simulation. However, the integration is frequently challenging
as each system is designed individually with different characteristics, such as
time granularity. Understanding the impact of time granularity on propagation
of disruptions between businesses and infrastructure systems and finding the
appropriate granularity for the SoS simulation remain as major challenges. To
tackle these, we explore how time granularity, recovery time, and disruption
size affect the propagation of disruptions between constituent systems of an
SoS simulation. To address this issue, we developed a High Level Architecture
(HLA) simulation of 3 networks and performed a series of simulation
experiments. Our results revealed that time granularity and especially recovery
time have huge impact on propagation of disruptions. Consequently, we developed
a model for selecting an appropriate time granularity for an SoS simulation
based on expected recovery time. Our simulation experiments show that time
granularity should be less than 1.13 of expected recovery time. We identified
some areas for future research centered around extending the experimental
factors space.
