Interventions

Contents:

• Interventions: changes to the state independent from the contagion model.

• Definition: Syntax for the definition of interventions

• Examples

Introduction

Synopsis

Interventions: changes to the state independent from the contagion model.

An intervention describes changes to the system state independent from the contagion model. The intervention happens when a Trigger evaluates to true. The trigger may be defined locally in the intervention itself or externally. External triggers refer to the interventions they trigger by the the unique id. When an intervention is triggered a user defined Action Ensemble is applied to a target Sets (nodes \(N\) and/or edges \(E\)) of the Contact Network. Note, it is possible that the target set may be empty. In that case only action specified under once in the Action Ensemble are applied.

Definition

Synopsis

Definition: Syntax for the definition of interventions

intervention: (id | trigger) target actionEnsemble [annotation]
target:       setContent [annotation]

An intervention mus either have unique id so that it can be referenced by an externally defined trigger or it a locally defined trigger.

Table 14 Intervention definition.

Name	Type	Description
id	uniqueId	An id which has to be unique within the list of interventions
trigger	object	The Trigger which must be true in oder for the action ensemble to be applied.
target	object	The Sets (nodes \(N\) and/or edges \(E\)) of the Contact Network
actionEnsemble	object	The Action Ensemble applied to the target set .
ann:*	annotation	Optional annotation of the intervention

Examples

Intervention to maintain the day of the week. This intervention is triggered at every tick. Note the variable \(week\_day\) is reset every seven days:

"variables": [
  {
    "id": "week_day",
    "initialValue": 0,
    "scope": "local",
    "reset": 7
  }
],
"interventions": [
  {
    "ann:id": "maintain_week_day",
    "ann:label": "update the week_day",
    "trigger": {
      "value": true
    },
    "target": {
      "set": {
        "idRef": "%empty%"
      }
    },
    "once": [
      {
        "operations": [
          {
            "target": {
              "variable": {
                "idRef": "week_day"
              }
            },
            "operator": "+=",
            "value": {
              "number": 1
            }
          }
        ]
      }
    ]
  }
]