Feedback Service

This service enabled the MAPE-K feedback control loop for existing process-models and -execution engines within CPS.

See the following publication for more detail:

Seiger, R., Huber, S., Heisig, P., & Assmann, U. (2016, June). Enabling Self-adaptive Workflows for Cyber-physical Systems. In International Workshop on Business Process Modeling, Development and Support (pp. 3-17). Springer International Publishing.

• Run: OPENHAB_HOST=172.17.0.1 docker-compose up
• Build: ./gradlew buildDocker

To get the host's address (OPENHAB_HOST), check the IP of the docker network interface (docker0). If you're using an external Neo4j instance, the version should be less or equal to 2.3.6.

• 9000: MAPE-K (feedback service)
  • example DogOnt/OpenHAB instances: examples/openhab-instance.ttl (file type: "text/turtle" for context creation)
• 5602: Kibana (metrics visualization)
  • index pattern: mapek-*
  • example visualizations and dashboard: examples/kibana-export.json
• 7474: Neo4j (context and domain graph)
  • web interface for graph visualization
• 9200: Elasticsearch HTTP (metrics index)
  • index: mapek-*

Operation

Create a context with the DogOnt-Plugin

Given an OpenHAB service with semantic binding running on localhost:8080 execute the following HTTP request. After the context has been created, it will be updated constantly. The response includes the location of the new context for further reference.

For importing a Context from Turtle-Format (*.ttl) use the mime Type text/turtle

POST /contexts HTTP/1.1
Host: localhost:9000
Content-Type: application/json

{
    "name": "home",
    "imports": [{
        "source": "classpath:dogont.owl",
        "mimeType": "application/rdf+xml",
        "name": "ontology"
    },{
        "source": "http://172.17.0.1:8080/rest/semantic",
        "mimeType": "application/rdf+xml",
        "name": "items"
    }]
} 

Create a Workflow

Use your own context reference URL, created by the previous post!

POST /workflows HTTP/1.1
Host: localhost:9000
Content-Type: application/json

{
    "name": "cooking with friends scenario",
    "context": "http://localhost:9000/context/3227"
}

Create a Process Goal

Use your own workflow reference URL, created by the previous post!

POST /goals HTTP/1.1
Host: localhost:9000
Content-Type: application/json

{
    "name": "enough light for cooking",
    "workflow": "http://localhost:9000/workflows/12916",
    "objectives": [{
        "name": "kitchen light intensity > 865 lux within two seconds",
        "satisfiedExpression": "#lightIntensity > 865",
        "compensateExpression": "#objective.created.isBefore(#now.minusSeconds(2))",
        "testNodeIdExpression": "#stateId",
        "contextExpressions": [
            "MATCH (thing)-[:type]->(sensor {name: 'LightSensor'})",
            "MATCH (thing)-[:isIn]->(room {name: 'Kitchen_Mueller'})",
            "MATCH (thing)-[:hasState]->(state:LightIntensityState)",
            "MATCH (state)-[:hasStateValue]->(value)",
            "RETURN avg(toFloat(value.realStateValue)) AS lightIntensity, head(collect(id(state))) AS stateId"
        ]
    }]
}

Available Variables/Functions

• objective: gives the whole objective bean (usage: #objective.created)
• lastCommandSendBefore(Objective, seconds): returns true if the last command, which was send to reach the objective, was send before the given amount of seconds (usage: #lastCommandSendBefore(#objective, 5))

IDE-Import

IntelliJ

1. File > New > Project from existing Sources
2. Select build.gradle from the project's root

Eclipse

1. Execute on command line
   • Unix: ./gradlew eclipse
   • Windows: gradlew.bat eclipse
2. File > Import > Existing Projects into Workspace
3. Choose the project's root directory
4. Check Search for nested Projects