Comparative approaches for assessing network vulnerability

A common theme in analysis and evaluation of network-based critical infrastructure is the assessment of system vulnerability. Graph theoretic, simulation, and optimization-based techniques have played a significant role in examining potential network vulnerabilities given the insights they can provide for mitigating facility loss and prioritizing fortification efforts. Central to these approaches is the concept of facility (arc-node) importance or criticality to system survivability. Assessments of network vulnerability can dramatically differ based on how facility importance is characterized. In this review, various approaches for assessing facility importance and network vulnerability are examined. The key differences in these approaches are the ways in which a facility's role in maintaining network operability is evaluated given arc-node disruption. Comparative results suggest significant differences exist among measures of facility importance and network performance. Furthermore, the subsequent incongruities in these measures and their implications need to be clearly understood to support interdiction risk and vulnerability assessment for critical infrastructures.