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Author:	le_roi_ponpon [ Sat 15. Feb 2014, 18:56 ]
Post subject:	Tips?
Hello, I would need some advise from the experts! There are a few cases that I wonder how to take into account with qualitative modelling. 1) constraints: for example, can we specify that a factor has only positive values? I believe that the insight matrix may be different if a factor becomes and remains 0 after a few time steps (hence has no impact after a few time steps), instead of becoming negative..and if it becomes negative, does it mean that its influence changes sign?? Or for example upper limit: water in dam cannot increase indefinitely, which affects the influence it may have on other factors (hence the insight matrix): when the dam is full then its influence remains constant. Another example is when trying to represent a change in land use for a given territory, e.g. pasture area increases at the expense of forest area (%forest+%pasture=100), i.e. more forest area leads (immediately) to less pasture area and vice-versa, since the total area is constant. Moreover, forest or pasture area cannot be negative, nor it can be larger than the total area. Here again, the insight matrix should be different if we take that into account.. 2) periodic factors, e.g. seasonality of rainfall, and discrete events (e.g. a flood that lasts one time step) 3) stochastic factors/influences Perhaps none can be considered in qualitative modelling, which is fine, but perhaps there are tricks? Thanks in advance! Grégoire

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