AgentBasedModels by dandanhuanghuang

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									Agent-Based Models
   An agent-based model is one in which the basic unit of
    activity is the agent.

   Usually a model will contain many agents (at least tens,
    occasionally many thousands).

   Its outcomes are determined by the interactions of the
    agents.

   A agent is an identifiable unit of computer program code
    which is autonomous and goal-directed.

    (from Schelhorn, O’Sullivan, Haklay, Thurstain-Goodwin,
    1999)
Agent-Based Models
   An early example of agent-based modeling is Boids (Reynolds,
    1987), a model that describes flocking behavior.

   Explaining flocking using functional models is complex.

   By approaching it by modeling autonomous agents with simple
    rules, it was easier to create an explanatory model.

   Agent models typically work by maintaining a collection of
    agents, and a timer that advances the state of each agent with
    each tick, each agent updating its state based on
    characteristics and location of the other agents and
    representations of other entities in the landscape.

   Agent models are best implemented in an object-oriented
    fashion
Agent-Based Models
Each agent has a simple set
         of rules defining its
         behavior. Creating
   multiple instances of the
   model and adjusting the
   rules made it possible to
    model flocking behavior
                   concisely.


            Boids animation
    More elaborate example
Agent-Based Models
 These animations exhibit the phenomenon of
  emergence, whereby complex behavior emerges from
  the behavior of simple components.

 Another example of agent-based modeling is pedestrian
  modeling:

    Pedestrian model – note formation of lanes.
    Other sample pedestrian models
Agent-Based Models
   Pedestrian model
    implementation
      (Batty, 1999)
Agent-Based Models
   Pedestrian model
    implementation
      (Batty, 1999)
Agent-Based Models
   Pedestrian model
    implementation
      (Batty, 1999)
Agent-Based Models
   Pedestrian model
    implementation
      (Batty, 1999)
Pedestrian model design (Schelhorn, O’Sullivan, Haklay, Thurstain-Goodwin, 1999)
Software for agent-
    based modeling
       (from Najlis,
      Janssen, and
      Parker, 2001)

								
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