Fig. 1
From: Snoopy’s hybrid simulator: a tool to construct and simulate hybrid biological models
A simple example illustrating the operation of hybrid Petri nets: (a) the HPN representation of simplified calcium dynamics, (b) a time course of opening and closing of the calcium channel, and (c) the corresponding calcium concentration. The two discrete places close and open represent the channel states, closed and opened, respectively. The two stochastic transitions: ch_open and ch_close model the state transition of the channel. The continuous place Ca models the calcium concentration. The calcium inflow is modelled via the continuous transition Ca_inflow which has a rate proportional to the open state of the channel. The outflow of the calcium is modelled using the transition Ca_pump. The simulation result of the model is given in (b) and (c)