Ontological annotation of data

Basic annotation knowledge with OEM

Ontological annotation of data means that data is linked to ontological concepts in the metadata.

In SEDOS we use the oemetadata v.1.5.1 (OEM) as metadata standard. For more context about the OEM-keys in oemetadata v.1.5.1, see here.

In energy systems modelling, data is fed into a model via parameters and their associated values. In the following, when we speak about ontological annotation, we, therefore, speak of parameter names, which are linked to an ontological concept for definition.

The linkage of parameter name and ontological concept in OEM has three elements:

1. user-defined parameter name
2. human-readable ontological concept name
3. Internationalized Resource Identifier (IRI)

Below the general section of the oemetadata v1.5.1 is shown, relevant for the ontological annotation of the table content itself.

• The general content of the table is annotated in the subject key

{
  "name": null,
  "title": null,
  "id": null,
  "description": null,
  "language": [
    null
  ],
  "subject": [
    {
      "name": null,
      "path": null
    }
  ],
  "keywords": [
    null
  ],
  "publicationDate": null
}

Below the resource section of the oemetadata v1.5.1 is shown, relevant for ontological annotation of parameter names.

Link a parameter name to a suitable ontology concept

Background know-how

Parameters can occur in the column header or as column value when dealing with tabular data.

• A) Parameters in the column headers are annotated in the isAbout key.
• B) Parameters occurring within a column are annotated in the valueReference key.

{
  "resources": [
    {
      "profile": null,
      "name": null,
      "path": null,
      "format": null,
      "encoding": null,
      "schema": {
        "fields": [
          {
            "name": null,
            "description": null,
            "type": null,
            "unit": null,
            "isAbout": [
              {
                "name": null,
                "path": null
              }
            ],
            "valueReference": [
              {
                "value": null,
                "name": null,
                "path": null
              }
            ]
          }
        ]
      }
    }
  ]
}

A) Parameters in the column headers - using isAbout:

1. user-defined parameter name is put in name (OEM-key 15.6.1.1),
2. a suitable human-readable ontological concept name is put in name (OEM-key 15.6.1.5.1),
3. Internationalized Resource Identifier (IRI) is put in path (OEM-key 15.6.1.5.2)

For example: A column with values for the rotor diameter of a wind turbine:

id	wind_turbine	ro_diam
1	type A	50
2	type A	60
3	type A	70
4	type B	80
5	type B	110

{
  "resources": [
    {
      "profile": null,
      "name": null,
      "path": null,
      "format": null,
      "encoding": null,
      "schema": {
        "fields": [
          {
            "name": "wind_turbine",
            "description": null,
            "type": null,
            "unit": null,
            "isAbout": [
              {
                "name": "wind energy converting unit",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00000044"
              }
            ],
            "valueReference": [
              {
                "value": null,
                "name": null,
                "path": null
              }
            ]
          },
          {
            "name": "ro_diam",
            "description": null,
            "type": null,
            "unit": "meter",
            "isAbout": [
              {
                "name": "rotor diameter",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00020144"
              }
            ],
            "valueReference": [
              {
                "value": null,
                "name": null,
                "path": null
              }
            ]
          }
        ]
      }
    }
  ]
}

B) Parameters within a column - using valueReference and isAbout:

valueReference

1. user-defined parameter name is put in value (OEM-key 15.6.1.6.1),
2. a suitable human-readable ontological concept name is put in name (OEM-key 15.6.1.6.2),
3. Internationalized Resource Identifier (IRI) is put in path (OEM-key 15.6.1.6.3)

isAbout

When annotating using valueReference, don't forget to annotate the column itself in isAbout, as described in A).

For example: A column containing various types of fuels:

id	various_types_of_energy_carriers
1	coal_HCV
2	green_diesel
3	coal_LCV

{
  "resources": [
    {
      "profile": null,
      "name": null,
      "path": null,
      "format": null,
      "encoding": null,
      "schema": {
        "fields": [
          {
            "name": "various_types_of_energy_carriers",
            "description": null,
            "type": null,
            "unit": null,
            "isAbout": [
              {
                "name": "portion of matter",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00000331"
              }
            ],
            "valueReference": [
              {
                "value": "coal_HCV",
                "name": "anthracite",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00000058"
              },
              {
                "value": "green_diesel",
                "name": "biodiesel",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00000071"
              },
              {
                "value": "coal_LCV",
                "name": "lignite",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00000251"
              }
            ]
          }
        ]
      }
    }
  ]
}

With oemetadata builder

Annotation conventions for automatic data processing

In SEDOS, automatic data reasoning and processing are based mainly on ontological annotations in the metadata. Thus, thorough annotation and following the conventions are important for frictionless data processing.

• A) technology and technology_type (oem-key 6.1-2)
• B) for MiMo technologies the input and output energy vectors (oem-key 15.6.1.5.1-2)
• C) parameter names (oem-key 15.6.1.6.1-3)

A) technology and technology_type

The technology and technology_type columns from the oedatamodel-concrete are filled with the information from the subject key.

B) parameter names

Case1

In cases where there is a single suitable ontology concept in the OEO we'll use the keys isAbout, valueReference as explained above.

Case2

In cases where there are multiple ontology concepts in the OEO that are suitable by using them in composition we'll use them as list in the name key.

For example: thermal efficiency of a heat power plant (as column in a tabular data set)

The concept thermal efficiency is not (yet, as of 23.09.22) available in the OEO, but the concepts:

• 'heat generation process' http://openenergy-platform.org/ontology/oeo/oeo-physical/OEO_00010248
• 'energy conversion efficiency' http://openenergy-platform.org/ontology/oeo/OEO_00140049

{
  "resources": [
    {
      "profile": null,
      "name": null,
      "path": null,
      "format": null,
      "encoding": null,
      "schema": {
        "fields": [
          {
            "name": "thermal efficiency",
            "description": "The column holds the values of the thermal efficiency of a heat power plant",
            "type": null,
            "unit": null,
            "isAbout": [
              {
                "name": "heat generation process",
                "path": "http://openenergy-platform.org/ontology/oeo/oeo-physical/OEO_00010248"
              },
              {
                "name": "energy conversion efficiency",
                "path": "http://openenergy-platform.org/ontology/oeo/OEO_00140049"
              }
            ],
            "valueReference": [
              {
                "value": null,
                "name": null,
                "path": null
              }
            ]
          }
        ]
      }
    }
  ]
}

Case3

In cases where there is NO suitable ontology concept in the OEO we'll copy the term used in the data directly to the namekey for further data processing in SEDOS.

Note

This is SEDOS-specific and needed for data processing. Normally one would leave the annotation in `isAbout` empty.

For example: fantasy power plant parameter

{
  "resources": [
    {
      "profile": null,
      "name": null,
      "path": null,
      "format": null,
      "encoding": null,
      "schema": {
        "fields": [
          {
            "name": "fantasy power plant paramter",
            "description": "The column holds values of a parameter, whose concept is not yet available in the OEO, of a fantasy power plant ",
            "type": null,
            "unit": null,
            "isAbout": [
              {
                "name": "fantasy power plant parameter",
                "path": null
              }
            ],
            "valueReference": [
              {
                "value": null,
                "name": null,
                "path": null
              }
            ]
          }
        ]
      }
    }
  ]
}