Ann Nicholson (Monash University)
Bayesian Networks for Biosecurity Risk Assessment

Bayesian networks (BNs) are rapidly becoming a tool of choice for ecological and environmental modelling and decision making. By combining a graphical representation of the dependencies between variables with probability theory and efficient inference algorithms, BNs provide a powerful and flexible tool for reasoning under uncertainty.  The popularity of BNs is based on their ability to reason both diagnostically and predictively, and to explicitly model causal interventions and cost-benefit trade-offs.

In Australia, current biosecurity risk assessments are typically qualitative, combining assessment across the stages of importatation, distribution, entry, establishment and spread. In this seminar, I will show a BN that directly models the current qualitative method.  I'll then adapt the BN to explicitly model the volume of infestation, adding clarity and precision.  I will demonstrate how more complex BNs can explicitly model the factors influencing each stage, and can be extended with management decisions and cost functions for decision making.