14.3. Interleaved Agent Simulation14.3.1. Case Study: A Four Stage Supply Chain (45/53)14.3.2. Case Study: A Signaling Game

14.3.1. Case Study: A Four Stage Supply Chain

A four stage supply chain consists of a retailer, a wholesaler, a distributor and a factory. While the factory is a top SC node, which only receives orders from and ships the ordered items to its downstream node, all others also receive deliveries from and send orders to their upstream nodes.

For getting a quick impression, you can run this model from the Sim4edu website, or inspect its OESjs code.

Conceptual Model
Conceptual Information Model

The potentially relevant object types are:

  1. top supply chain nodes (like the factory),
  2. intermediate supply chain nodes (like the wholesaler and distributor),
  3. bottom supply chain nodes (like the retailer).

Potentially relevant types of events and activities are:

  1. receive order (from the downstream node or from end customer),
  2. end of week,
  3. send order (to the upstream node),
  4. ship items (to the downstream node),
  5. perceive reception of items (receive delivery).

Object, event and activity types, together with their participation associations, can be visually described in a conceptual information model in the form of a conceptual Object Event (OE) class diagram.

conceptual information model describing object, event and activity types
Conceptual Process Model
A conceptual process model in the form of a BPMN diagram
Simulation Design

Each SC node is modeled as an agent that reacts to

  1. the in-message event "receive order",
  2. the perception event "perceive reception of items" (delivery), and
  3. the time event "end of week",

and performs

  1. the out-message action "send order" and
  2. the action "ship items".
Information Design Model

T.B.D.

An information design model, in the form of an OE class diagram as shown below, is derived from a conceptual information model by abstracting away from items that are not design-relevant and possibly adding certain computational details.

Process Design Model

T.B.D.

A process design model, in the form of a DPMN process diagram as shown below, is derived from a conceptual process model by abstracting away from items that are not design-relevant and possibly adding certain computational details.

A DPMN process design model essentially defines the admissible sequences of events and activities together with their dependencies and effects on objects, while its underlying OE class design model defines the types of objects, events and activities, together with the participation of objects in events and activities, including the resource roles of activities, as well as resource multiplicity constraints, parallel participation constraints, alternative resources, and task priorities.

It is an option, though, to enrich a DPMN process design model by displaying more computational details, especially the recurrence of exogenous events, the duration of activities and the most important resource management features defined in the underlying OE class design model, such as resource roles (in particular, performer roles can be displayed in the form of Lanes) and resource multiplicity constraints. The following model shows an enriched version of :

Such an enriched DPMN process design model includes all computational details needed for an implementation without a separate explicit OE class design model. In fact, such a process model implicitly defines a corresponding class model. For instance, the enriched DPMN model of implicitly defines the OE class model of above.

Combined with its underlying OE class design model, a DPMN process design model provides a computationally complete specification of a simulation model.