Simulistics

This is the home page for SimileXML: XML-based languages and tools for Simile-related modelling.

languages in the plural, since there are alternative Schema for Simile model-representation languages themselves, plus we want look at other XML-based languages, e.g. simplified notation for representing simple System Dynamics models.

tools, since it is not just the languages we are considering but the tools (e.g. XSLT or XSugar based) for processing models expressed in the language.

The old content is being copied to Drupal pages with url aliases to match the old urls. At present the url base is set to /drupal so all Drupal page urls start with that. When we want to switch over to Drupal we can change the url base in Drupal site settings and possibly .htaccess.

Links must be checked.

Appearance must be finalised - make our own CSS using the existing simulistics.css

Reference material about the Drupal installation for simulistics.com

This is a simple example of optimizing output of a Simile model using SimileScripting and the Tcllib optimization package math::optimize. The script illustrates how to tackle this kind of problem.

This section deals with using SimileScript to automate simulations, ie runs of a model.

Many environmental factors vary on a daily or an annual basis: e.g. temperature, radiation, evapotranspiration. It is desirable to be able to capture this if you want to capture the effect of the factor on the behaviour of your modelled system, and if the time-scale is appropriate.

Let’s assume that your time unit is the month (i.e. all your rates are expressed per month, and that simulation time is shown in month).

We can combine the use of the time function with the sketched graph. This is very useful when you have a historical record for some external factor, e.g. rainfall or temperature: the graph you sketch is a copy of the historical record.

It is often useful to be able to use current simulation time in your model: for example, you may want to incorporate a gradual increase in some external variable such as temperature. For this purpose, a special function called time is provided in Simile.

Many ecological processes are influenced by several factors together. For example, plant growth may be influenced by temperature, radiation, and soil water content. It is often difficult to know how to combine the effect of these factors.

Sometimes, the usual mathematical expressions aren’t enough. For example, although it’s easy to say that one variable is proportional to another, by multiplying it by a constant, it’s much harder to say that the value of a variable depends on whether another variable is above or below a threshold value. Simile’s equation language provides if...then statements as a way of handling these either / or situations.