P.S. Thiagarajan NUS Title: Probabilistic Approximations of ODEs Based Bio-pathways Dynamics Abstract: A system of Ordinary Differential Equations (ODEs) is often used to model the dynamics of a bio-chemical network. Such systems are difficult to analyze. To get around this, we construct a discrete probabilistic approximation of the ODE dynamics as a dynamic Bayesian network. Consequently, pathway properties can be analyzed using standard Bayesian inference techniques. We have tested our method on a number of pathways models. We have also carried out a combined computational and experimental study of the complement system under inflammation conditions. The results we obtain are very promising in terms of both accuracy and efficiency. Further, our method appears to be amenable to a fast GPU based implementation.