Journal on Policy & Complex Systems Volume 3, Issue 2 | Page 176

Simulating Heterogeneous Farmer Behaviors
Figure 3 . Simulated farm size distribution .
Network and Layout
An agent is assumed to operate a farm that consists of a number of parcels . The agents are placed at the center points of their farms , which are determined using GIS data . Each agent is connected to a number of neighbors based on geographic proximity and influences those neighbors . The modeler at the beginning of each simulation determines the number of agents in one neighbor group .
ABM Model Framework
In the ABM , we adopt the modification of the classic model in environmental and resource economics as documented in our previous section . Each agent operates a farm , generates income by producing an agricultural product ( e . g ., corn ), and simultaneously generates byproducts that cause NPS pollution . The agents may choose to adopt a technology at a cost proportional to its size that could reduce byproducts . As explained before , an underlying dominant Nash strategy could be solved for every agent in the watershed . Since the dominant Nash strategy is the same as the optimal strategy for the social planner ’ s problem , we can treat the Nash strategy as the “ Theoretical Target ” level of participants ’ response . A pollution monitor ( i . e ., sensor ) is placed at the downstream end of the watershed , and amount of pollution contributed by each farm is based on the farm ’ s distance from the monitoring point ( our experiment measured individual contributions of pollution in the same way ). Different policy and regulatory scenarios influence the agents ’ production and technology-adoption decisions based on results drawn from the experiment . Table 1 summarizes the variables used in the ABM .
ABM Model Process Flow
Figure 4 demonstrates the process flow of our ABM . Each agent makes two decisions , a production decision , and a technology decision . Both decisions influence the income received and the pollution generated by the agent . Combined with pollution generated by other agents , the total pollution is calculated . Depending on whether
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