  We present an XML-based simulation authoring environment. The proposed
description language allows to describe mathematical objects such as systems of
ordinary differential equations, partial differential equations in two
dimensions, or simple curves and surfaces. It also allows to describe the
parameters on which these objects depend. This language is independent of the
target software and allows to ensure the perennity of author's work, as well as
collaborative work and content reuse. The actual implementation of XMLlab
allows to run the generated simulations within the open source mathematical
software Scilab, either locally when Scilab is installed on the client
machines, or on thin clients running a simple web browser, when XMLlab and
Scilab are installed on a distant server running a standard HTTP server.
