# Differences

This shows you the differences between two versions of the page.

Both sides previous revision Previous revision Next revision | Previous revision | ||

agent_based_model:start [2013/02/15 19:55] britaldo |
agent_based_model:start [2013/02/18 18:54] (current) juliana [Download our AMB model and run it yourself.] |
||
---|---|---|---|

Line 1: | Line 1: | ||

====== Spatially explicit agent based model of rabbit population ====== | ====== Spatially explicit agent based model of rabbit population ====== | ||

+ | **Alessandro Ribeiro Campos, Juliana Leroy Davis, William Leles Souza Costa and Britaldo Silveira Soares Filho** | ||

\\ | \\ | ||

\\ | \\ | ||

Line 24: | Line 25: | ||

Some of these applications take advantage of the spatial dynamic representation of CA models. This possibility was explored particularly by Epstein and Axtell (1996) who developed an ABM of an artificial society, known as Sugarscape, for the study of social phenomena and human behavior. | Some of these applications take advantage of the spatial dynamic representation of CA models. This possibility was explored particularly by Epstein and Axtell (1996) who developed an ABM of an artificial society, known as Sugarscape, for the study of social phenomena and human behavior. | ||

- | Here we describe a spatially explicit ABM developed using DINAMICA-EGO to represent the dynamics of a population of rabbits.\\ | + | Here we describe a spatially explicit ABM developed using DINAMICA-EGO to represent the dynamics of a population of rabbits This model was developed as part of the modeling worshop class of the graduate course on Environmental Modeling at UFMG.\\ |

\\ | \\ | ||

\\ | \\ | ||

Line 106: | Line 107: | ||

The model iterates as follows: | The model iterates as follows: | ||

- | {{ :agent_based_model:pop_landscape3.jpg |}} | + | {{ :agent_based_model:pop_landscape4.jpg |}} |

**Births** | **Births** | ||

Line 124: | Line 125: | ||

Recovery occurs every time step according to the current amount of resources in the cell and the maximum capacity of resources using a logistic function.{{ :agent_based_model:mils.jpg |}}{{ :agent_based_model:movement_intake_and_recovery.jpg |}} | Recovery occurs every time step according to the current amount of resources in the cell and the maximum capacity of resources using a logistic function.{{ :agent_based_model:mils.jpg |}}{{ :agent_based_model:movement_intake_and_recovery.jpg |}} | ||

- | -Death: | + | **Death:** |

There are two causes of death:\\ | There are two causes of death:\\ | ||

- | -Starvation: lack of enough energy to stay alive. It occurs when the agent's stock reaches zero calories.\\ | + | **Starvation:** lack of enough energy to stay alive. It occurs when the agent's stock reaches zero calories.\\ |

- | -Age: the number of deaths in a time step is defined by the average of a normal distribution of the agent lifespan. The model uses a stochastic draw to determine whether the agent lives or dies.\\ | + | **Age:** the number of deaths in a time step is defined by the average of a normal distribution of the agent lifespan. The model uses a stochastic draw to determine whether the agent lives or dies.\\ |

\\ | \\ | ||

\\ | \\ | ||

Line 135: | Line 136: | ||

===== Scenarios ===== | ===== Scenarios ===== | ||

- | We ran the model under different scenarios represented as different landscape maps (100×100 raster). The amount and distribution of the resources were modified to analyze population dynamics of agents, patterns resulting from agent movement, resources depletion, and population energy inequality. | + | We ran the model under different scenarios represented as different landscape maps (100×100 raster). The amount and distribution of the resources were modified to analyze population dynamics, patterns resulting from agent movements, resource depletion, and population calorie inequality. |

==== Homogeneous 100 ==== | ==== Homogeneous 100 ==== | ||

Line 168: | Line 169: | ||

{{ :agent_based_model:gini_coefficient_new2.jpg |}} | {{ :agent_based_model:gini_coefficient_new2.jpg |}} | ||

Gini Coefficient in three different landscapes: Hom 100- with resources distributed homogeneously, Het 100-with the same amount of resources distributed heterogeneously and Het 50-with half of resources amount distributed heterogeneously | Gini Coefficient in three different landscapes: Hom 100- with resources distributed homogeneously, Het 100-with the same amount of resources distributed heterogeneously and Het 50-with half of resources amount distributed heterogeneously | ||

+ | |||

+ | [[:agent_based_model: gini_calculation|Here]] you can see how Gini Coefficient is calculated\\ | ||

==== Population ==== | ==== Population ==== | ||

Line 221: | Line 224: | ||

- | On heterogeneous landscapes, the agents move to locations with larger concentration of resources. As a result, this areas are depleted first. | + | On heterogeneous landscapes, the agents move to locations with larger concentration of resources. As a result, this areas are depleted in first place. |

==== Conclusions ==== | ==== Conclusions ==== | ||

Line 238: | Line 241: | ||

- | [[http://www.csr.ufmg.br/wiki/Model.ego|Download model]] | + | [[http://csr.ufmg.br/~bruno/Rabbit_population_ABM.zip|Download model]] ( with Gini Coefficient Submodel and Heterogeneous lanscape 100 map input included) |

==== Download model inputs ==== | ==== Download model inputs ==== | ||

Line 254: | Line 257: | ||

- | It is a measure of inequality developed by the Italian statistician Corrado Gini and published in 1912. It varies from 0 to 1; 0 corresponds to complete equality and 1 corresponds to complete inequality. We use the GINI index to measure the inequality in the rabbit calorie distribution.. | + | It is a measure of inequality developed by the Italian statistician Corrado Gini and published in 1912. It varies from 0 to 1; 0 corresponds to complete equality and 1 corresponds to complete inequality. We use the GINI index to measure the inequality in the rabbit calorie distribution. |

+ | | ||

+ | [[:agent_based_model: gini_calculation|Gini Coefficient Calculation]] | ||

+ | | ||

+ | Here you can download Gini Coefficient Submodel separately.\\ | ||

+ | To open it with the ABM you can follow the [[:submodels#sharing |instructions here]]. | ||

- | [[http://www.csr.ufmg.br/wiki/CalculateGiniCoefficientMap.egoml|Download Gini Coefficient submodel]]\\ | + | [[http://csr.ufmg.br/~bruno/Gini_Coefficient.ego|Download Gini Coefficient submodel]]\\ |

\\ | \\ | ||

\\ | \\ |