Integrated Cyber-Physical Simulation of ...

In cyber-physical systems (CPSs), embedded computing systems and communication capability are used to streamline and fortify the operation of a physical system. Intelligent critical infrastructure systems are among the most important CPSs and also prime examples of pervasive computing systems, as they exploit computing to provide "anytime, anywhere" transparent services. While the added intelligence offers the promise of increased utilization, its impact must be assessed, as unrestricted cyber control can actually lower the reliability of existing infrastructure systems. As a practical example, water distribution networks (WDNs) are an emerging CPS domain. Physical components, e.g., valves, pipes, and reservoirs, are coupled with the hardware and software that support intelligent water allocation. Information such as demand patterns, water quantity (flow and pressure head), and water quality (contaminants and minerals) is critical in achieving this goal, and beneficial in guiding maintenance efforts and identifying vulnerable areas requiring fortification and/or monitoring. Sensors dispersed in the physical infrastructure collect this information, which is fed to algorithms (often distributed) running on the cyber infrastructure. These algorithms provide decision support to hardware controllers that are used to manage the allocation (quantity) and chemical composition (quality) of the water. As WDNs become larger and more complex, their reliability comes into question.