Time Granularity in System-of-Systems Simulation of Infrastructure Networks

Because of their extreme complexities, a system-of-systems (SoS) approach is often used for simulating infrastructure systems. This allows the user to integrate models of various systems into one simulation. However, this integration presents several issues because individual simulations are often designed for only a specific purpose and context. This leads to variations among space granularities and proposes a challenge when selecting an appropriate time granularity for the overall SoS simulation. To explore how this granularity might affect the outcome of simulations, we designed and developed a prototype system of three infrastructure simulation networks that were then combined into one SoS simulation using High Level Architecture (HLA) implementation. We then performed a series of experiments to investigate the response of the simulation to varying time granularities. Our examination included a propagation of disruptions among constituent simulations to estimate how this was affected by the frequency of updates between those simulations, i.e. time granularity. Our results revealed that the size of the simulated disruption decreased with increasing time granularity and that the simulated recovery time was also affected. In conducting this project, we also identified several ideas for future research that could focus on a wider range of disruption generators and infrastructure systems in those SoS simulations

DMA optimal layout for protection of water distribution networks from malicious attack

Water distribution networks (WDNs) are among the most important civil networks, because they deliver drinking and industrial water to metropolitan areas, supporting economic prosperity and quality of life. Therefore, they constitute critical infrastructures (CIs) as systems whose operability are of crucial importance to ensure social survival and welfare. In the last years, extreme natural events and intentional malicious attacks have shown that global safeguard of systems cannot be ever performed. In this regard, critical infrastructure protection (CIP) strategies should be focused both on the prevention of these events and on the procedures for the functioning recovery and damage limitation. In this paper, starting from previous works of the authors, the impact of an intentional contamination attack to water distribution network and a possible strategy to mitigate the user risk have been studied, simulating the introduction of potassium cyanide with a backflow attack into water system. As protection technique, the water network partitioning (WNP) has been adopted in order to improve the management and also to reduce the extent of damage showing a dual use-value. WNP reveals to be an efficient way to protect water networks from malicious contamination, through the closure of gate valves by a remote control system creating semi-independent District Meter Areas (DMAs). The study also investigates the possibility to identify a priori the most critical point of a water distribution network for the malicious attack through a novel procedure based on topological metric. The methodology, tested on a real medium size water network in Italy, shows very interesting results in terms of mitigation risk

DMA optimal layout for protection of water distribution networks from malicious attack

Water distribution networks (WDNs) are among the most important civil networks, because they deliver drinking and industrial water to metropolitan areas, supporting economic prosperity and quality of life. Therefore, they constitute critical infrastructures (CIs) as systems whose operability are of crucial importance to ensure social survival and welfare. In the last years, extreme natural events and intentional malicious attacks have shown that global safeguard of systems cannot be ever performed. In this regard, critical infrastructure protection (CIP) strategies should be focused both on the prevention of these events and on the procedures for the functioning recovery and damage limitation. In this paper, starting from previous works of the authors, the impact of an intentional contamination attack to water distribution network and a possible strategy to mitigate the user risk have been studied, simulating the introduction of potassium cyanide with a backflow attack into water system. As protection technique, the water network partitioning (WNP) has been adopted in order to improve the management and also to reduce the extent of damage showing a dual use-value. WNP reveals to be an efficient way to protect water networks from malicious contamination, through the closure of gate valves by a remote control system creating semi-independent District Meter Areas (DMAs). The study also investigates the possibility to identify a priori the most critical point of a water distribution network for the malicious attack through a novel procedure based on topological metric. The methodology, tested on a real medium size water network in Italy, shows very interesting results in terms of mitigation risk