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Slide 15 of 21
The program that I used for modeling alfalfa seed pollination was Stella II,
an easy-to-use program for systems modeling. One starts by creating a flow
chart that contains three elements:
Stocks are accumulations. They collect inflows and lose outflows. Flows fill
and drain accumulations. The arrowhead on the flow pipe indicates the
direction of flow. Finally, converters change inputs to outputs. They hold
constants, graphs, and calculate algebraic relationships. For example, in my
model open, unpollinated flowers are a stock with an inflow of buds opening,
and outflows of pollinated flowers ready to develop pods.