From: Damien Joly <do_joly@...>
Date: 2002-03-22T06:53:07+09:00
Subject: Re: disease model

> > What's an ODE?
> 
> Sorry, ordinary differential equation. The system
> evolves according to
> the equations until some guard condition becomes
> true (typically a
> threshold crossing), and then some discrete state
> changes happen. When
> no more discrete transitions are possible,
> continuous evolution resumes.

This is very interesting.  Disease transmission has
traditionally been modelled with ODEs (as it occurs in
continuous time), but wildlife people like to model
things in discrete time (because of things like spring
birth "pulses").  A hybrid approach such as the one
you suggest might be a way to merge the two time
scales ...

Damien

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