LinkedFactory: Industrial Digital Twins

What is LinkedFactory?

LinkedFactory defines APIs and a JSON-based data format for managing time series data about assets to create connected digital representations of technical systems.

The core components can be augmented with RDF-based descriptions for representing metadata like the structure, components or attributes of assets as well as other provenance information of time series data. In this context SPARQL can be used to execute queries against time series data and the related metadata.

Components

LinkedFactory is based on the following standards and components:

Core components:

API for storing and retrieving time series data
flexible JSON-based format for exchanging data

Optional components for metadata:

RDF for metadata of assets with associated properties and relationships to other assets.
Graph Store HTTP Protocol as simple HTTP-based protocol for modifiying the RDF data about assets
SPARQL interface for complex queries against RDF and time series data

Graph store

The endpoint /models provides an interface according to the SPARQL 1.1 Graph Store HTTP Protocol.

The only difference is that the platform uses the parameter model instead of graph to specify the target named graph.

SPARQL interface

The endpoint /sparql provides an interface according to SPARQL 1.1.

The parameter model must be used to specify the target model for the query. The default model for LinkedFactory data is http://linkedfactory.iwu.fraunhofer.de/data/.

select ?property ?value ?time {
  service <kvin:> {
    <http://example.org/resource1>
       ?property [ <kvin:value> ?value; <kvin:time> ?time ; <kvin:limit> 1 ] .
  }
} order by ?time

Grafana Datasource

A Grafana Datasource for the LinkedFactory API is available at https://github.com/linkedfactory/linkedfactory-grafana-ds