X hits on this document





2 / 30

Following the general overview by Castle and Crooks [6] and elsewhere [7], a dynamic model is defined as a simplified representation of reality that evolves over time. The unstated art behind this method is the intuition/experience in creating a simulation that is sufficiently complex enough to show interesting dynamics of the system, while being simple enough to have a tractable software representation on a computing system.

In particular, dynamics” is defined in as the study of change and evolving systems [8], while “tractable” is an artifact of the particular tool used. As we shall see, ABM makes particular classes of problems very easy to solve, that would otherwise be very difficult to attack using more traditional dynamical methods.

For the purposes of this paper, an Agent, as part of an ABM system, is defined with the following characteristics:

  • Activity: Each agent independently acts according the rules of the simulation and their own pre- programmed behaviors. These rules and behaviors can take one or more of the following features:

  • o

    Goal-direction: The agent acts in such a way as to achieve a particular goal, which can be either a relative or extremal value. For example, an agent may be designed to maximize accumulation of a particular resource.

    • o

      Reactivity/Perceptivity: The agent senses its surroundings, or is supplied with a map such that it is aware of its environment. For example, an agent could be aware of resource node locations.

    • o

      Bounded Rationality: Generally, goal-direction in agents operates on the rational-choice principle, which generally implies unlimited access to information and computational resources. However, experimental evidence suggests that non-optimal decisions are often closer to reality. Therefore, in order to provide greater predictive power, the agents can be constrained in terms of information resources or analytical ability. For example, an agent might be able to sense only those resource nodes within a finite range, or possess a map of resources that does not take into account the actions of other agents.

    • o

      Interactivity: Continuing on the principle of bounded rationality, agents may interact or exchange information with other agents. These interactions may have particular effects on the agent, including its destruction or change in goal-seeking behavior.

    • o

      Mobility: Interactivity with the environment and other agents is vastly improved if the agent can roam the model space independently.

    • o

      Adaptation: Alteration of an agent’s current state based upon interactions with the environment or other agents provide a useful form of learning or memory. This adaptation can be provided for at the level of the individual agent, or groups of nearby agents, all the way up to the population level of the entire set of agents .

  • Autonomy: Each agent is free for activity as defined above, with the ability to make

independent decisions.

Document info
Document views53
Page views53
Page last viewedThu Oct 27 21:25:23 UTC 2016