HIERARCHAL INDUCTIVE PROCESS MODELING AND ANALYSIS ...

4 ANALYTICAL ANALYSIS
The quantitative analysis of HIPM’s results enabled us to make some useful observations.
Since the main purpose of this software for a biologist is to approximate
the natural system observed in order to use this model to perform experiments, we
decided to choose two of the models with an reMSE of less than 0.5 that came up
most frequently over all 31 runs.
4.1 Most recurrent models
The initial concept driving the models is represented in Figure 1. Phytoplankton
plays a role in both Zooplankton and Detritus concentration, it is acted upon by both
Nitrate and Iron which are in turned acted upon by Detritus. The environmental
factors act on the Phytoplankton concentration as well as Nitrate and Iron. Model
A came up 13 times and Model B came up 11 times over all runs. We analyzed these
models to figure out if their behavior make sense from an ecological standpoint and if
they could give us information on how to improve the HIPM selection process. The
models are composed of five differential equations, each one determined by one of
the five principal concentrations: Phytoplankton (P), Zooplankton (Z), Detritus (D),
Nitrate (N)and Iron (F). All theses entities are acted upon by sets of parameters
listed in Table 5 and 6.
There are also a set of exogenous variables acting on
the system, defined as follow: E P UR (t) is the photosynthetically usable radiation,
E T H2 O(t) is the temperature of the water and E ice (t) is the sea ice concentration.
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