IODA methodology

The formal model -- as a technical specification of the simulation -- cannot be defined directly by domain experts. Yet, their involvement in its construction is a prerequisite to valid simulation results. The IODA modeling methodology aims at dealing with this issue, thanks to simple specifications that are used in order to build gradually the model of the simulation.

Problem analysis outline

The construction of the computational model with the IODA modeling methodology is a process ruled by 7 different steps:

1. List the different interactions occurring in the simulation;
2. List the entities involved in the simulation. Each entity is represented by an agent family;
3. Specify the interaction matrix of the simulation, i.e. plug:
   • interactions between source and target agent families, and set its limit distance;
   • degenerate interactions for source agent families into the ∅ column of the matrix;
4. Specify the interactions involved in the simulation:
   • either write the interactions trigger, preconditions and actions. Writing them leads to the identification of the different abstract primitives that agents have to implement in order to participate in the interaction;
   • or get an already existing interaction from the interaction library, for which trigger, preconditions, actions and roles are already specified;
5. Specify the interaction selection process of agents. For reactive agents, it consists in providing a priority to every assignation element of the interaction matrix;
6. Specify the agent families involved in the simulation, i.e. specify:
   • the abstract primitives that the family has to implement, thanks to algorithms;
   • the halo of that family, depending on how the environment is represented;
   • the initialization and updating primitive of this family, thanks to algorithms;
7. Specify the remaining elements of the simulation:
   • how time is represented in the simulation;
   • what distance and halo stand for -- i.e. how the environment is represented;

Obviously, these steps are not an absolute and dogmatic sequential process. Even if each step has to be clearly identified, they are in practice intermingled during simulations specification. The only requirement is to build the interaction matrix and specify interactions before focusing on agents structure.

Illustration

An application of this process applied to a simple simulation (a termite nest construction) is described on this page. This example is inspired from the model described by Mitchel Resnick in his book entitled Turtles, termites, and traffic jams: explorations in massively parallel microworlds.