Anomaly Detection and Encrypted Programming Forensics for Automation Controllers

Securing the critical infrastructure of the United States is of utmost importance in ensuring the security of the nation. To secure this complex system a structured approach such as the NIST Cybersecurity framework is used, but systems are only as secure as the sum of their parts. Understanding the capabilities of the individual devices, developing tools to help detect misoperations, and providing forensic evidence for incidence response are all essential to mitigating risk. This thesis examines the SEL-3505 RTAC to demonstrate the importance of existing security capabilities as well as creating new processes and tools to support the NIST Framework. The research examines the potential pitfalls of having small-form factor devices in poorly secured and geographically disparate locations. Additionally, the research builds a data-collection framework to provide a proof of concept anomaly detection system for detecting network intrusions by recognizing the change in task time distribution. Statistical tests distinguish between normal and anomalous behaviour. The high true positive rates and low false positive rates show the merit of such an anomaly detection system. Finally, the work presents a network forensic process for recreating control logic from encrypted programming traffic

Estimation of critical and viscous frequencies for Biot theory in cancellous bone

The use of Biot theory for modelling ultrasonic wave propagation in porous media involves the definition of a ‘critical frequency’ above which both fast and slow compressional waves will, in principle, propagate. Critical frequencies have been evaluated for healthy and osteoporotic cancellous bone filled with water or marrow, using data from the literature. The range of pore sizes in bone gives rise to a critical frequency band rather than a single critical frequency, the mean of which is lower for osteoporotic bone than normal bone. However, the critical frequency is a theoretical concept and previous researchers considered a more realistic ‘viscous frequency’ above which both fast and slow waves may be experimentally observed. Viscous frequencies in bone are found to be several orders of magnitude greater than calculated critical frequencies. Whereas two waves may well be observed at all ultrasonic frequencies for water-filled cancellous bone at 20 °C, it is probable megahertz frequencies would be needed for observation of two waves in vivo