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Object-Event Modeling and Simulation

Object-Event Modeling and Simulation (OEM&S) is a general Discrete Event Simulation paradigm combining object-oriented modeling with the event scheduling paradigm. In OEM, the state structure of a system can be modeled with UML Class Diagrams defining both object and event types, and the system's dynamics can be modeled with conceptual process models (expressed, e.g., in BPMN) and process design models (expressed, e.g., in DPMN).

Agent/Object-Event Simulation (A/OES), is an extension of basic OES by adding the concepts of agents, perception, action and communication.

Sim4edu currently provides the OESjs simulation framework, which is a JavaScript implementation of the OES paradigm, or, more precisely, of its language OESL and its abstract simulator Omega-Epsilon-Sigma (ΩΕΣ) that supports both next-event time progression, as used in discrete event simulation, and fixed-increment time progression, as used in NetLogo-based social science simulations as well as in continuous state change simulations. The next simulator/framework on the roadmap of Sim4edu implements the A/OES paradigm for agent-based discrete event simulation and is called A-OESjs.

A real-world discrete event system (or discrete dynamic system) consists of:

This means that in order to model a discrete event system using OES, we have to

  1. Describe its object types and event types.
  2. Specify, for any event type, which causal regularity, responsible for state changes of objects and follow-up events, is triggered by events of that type. Causal regularities are captured by event rules.

The OES language (OESL) allows defining:

  1. Object types in the form of classes (of an object-oriented language like UML or JavaScript),
  2. Event types in the form of classes, and their event rules in the form of a special onEvent method in the corresponding event class.

OESL is a historic successor of ERSL, since the OES paradigm has been developed as a continuation of an earlier R&D project called Entity-Relationship Modeling and Simulation. Likewise, A/OESL is a historic successor of AORSL, since the A/OES paradigm has been developed as a continuation of an earlier R&D project called Agent-Object-Relationship Simulation.

In OES, two categories of simulated events are distinguished:

  1. Exogenous events occur, periodically, due to factors that are external to the simulation model. Their re-occurrence pattern is modeled in the form of a recurrence function.
  2. Caused events are simulated events that are caused by other simulated events.

An OES scenario consists of:

An OES model may include definitions of

An OES scenario simulation can be configured with