ParX-evaluator

ParX-evaluator is a Node.js/TypeScript framework for evaluating process parameter interdependencies in manufacturing knowledge graphs.
It uses SPARQL to traverse semantic models based on industrial standards according to the ParX ontology and mathjs for symbolic/numeric computation, enabling automated resolution of mathematical expressions modeled in OpenMath-RDF.

Usage

The evaluator connects to a SPARQL endpoint containing your manufacturing process knowledge graph, retrieves relevant mathematical expressions, resolves input parameters, and calculates results.

Start evaluation

Run directly with ts-node:

npm start {$graphRepo} {$processURI} {$parameterURI}

• $graphRepo – Name of the GraphDB repository (e.g., "TESTREPO"). The full endpoint URL http://localhost:7200/repositories/{name} is constructed automatically.
• $processURI – IRI of the process operator in the knowledge graph.
• $parameterURI – IRI of the parameter to be evaluated.

This will:

1. Retrieve the formula for the specified parameter.
2. Traverse the OpenMath-RDF expression tree.
3. Bind data elements and retrieve values.
4. (In case of missing values) Recursively resolve any missing values from upstream processes.
5. Compute and return the result.

Requirements

• Node.js (>= 16)
• A running SPARQL endpoint with a process model in RDF/OWL format
• Knowledge graph modeled according to existing industrial standard ontology design patterns (see https://github.com/hsu-aut/parx):
  • VDI/VDE 3682 – process modeling according to the formalized process description (fpd)
  • DIN EN 61360 – parameter characteristics
  • OpenMath-RDF – mathematical expressions