Work in progress

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:j.0="http://qudt.org/schema/qudt/"
    xmlns:j.1="http://purl.org/dc/terms/"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#" > 
  <rdf:Description rdf:about="http://qudt.org/vocab/unit/UNKNOWN">
    <rdf:type rdf:resource="http://qudt.org/schema/qudt/Unit"/>
    <j.1:description>Placeholder unit for abstract quantities</j.1:description>
    <j.0:hasDimensionVector rdf:resource="http://qudt.org/vocab/dimensionvector/NotApplicable"/>
    <j.0:hasQuantityKind rdf:resource="http://qudt.org/vocab/quantitykind/Unknown"/>
    <j.0:symbol>Unknown</j.0:symbol>
    <rdfs:isDefinedBy rdf:resource="http://qudt.org/2.1/vocab/unit"/>
    <rdfs:label xml:lang="en">Unknown</rdfs:label>
  </rdf:Description>
</rdf:RDF>

@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<http://qudt.org/vocab/unit/UNKNOWN>
  rdf:type <http://qudt.org/schema/qudt/Unit> ;
  <http://purl.org/dc/terms/description> "Placeholder unit for abstract quantities" ;
  <http://qudt.org/schema/qudt/hasDimensionVector> <http://qudt.org/vocab/dimensionvector/NotApplicable> ;
  <http://qudt.org/schema/qudt/hasQuantityKind> <http://qudt.org/vocab/quantitykind/Unknown> ;
  <http://qudt.org/schema/qudt/symbol> "Unknown" ;
  rdfs:isDefinedBy <http://qudt.org/2.1/vocab/unit> ;
  rdfs:label "Unknown"@en ;
.

{"resource":"Unknown" 
 ,"qname":"unit:UNKNOWN" 
 ,"uri":"http:\/\/qudt.org\/vocab\/unit\/UNKNOWN" 
 ,"properties":["description":"Placeholder unit for abstract quantities" 
    ,"has dimension vector":"dimension:NotApplicable" 
    ,"has quantity kind":"quantitykind:Unknown" 
    ,"isDefinedBy":"<http:\/\/qudt.org\/2.1\/vocab\/unit>" 
    ,"label":"Unknown" 
    ,"symbol":"Unknown" 
    ,"type":"qudt:Unit" 
    ]}

{
  "@id" : "http://qudt.org/vocab/unit/UNKNOWN",
  "@type" : "http://qudt.org/schema/qudt/Unit",
  "description" : "Placeholder unit for abstract quantities",
  "hasDimensionVector" : "http://qudt.org/vocab/dimensionvector/NotApplicable",
  "hasQuantityKind" : "http://qudt.org/vocab/quantitykind/Unknown",
  "symbol" : "Unknown",
  "isDefinedBy" : "http://qudt.org/2.1/vocab/unit",
  "label" : {
    "@language" : "en",
    "@value" : "Unknown"
  },
  "@context" : {
    "description" : {
      "@id" : "http://purl.org/dc/terms/description"
    },
    "hasDimensionVector" : {
      "@id" : "http://qudt.org/schema/qudt/hasDimensionVector",
      "@type" : "@id"
    },
    "hasQuantityKind" : {
      "@id" : "http://qudt.org/schema/qudt/hasQuantityKind",
      "@type" : "@id"
    },
    "symbol" : {
      "@id" : "http://qudt.org/schema/qudt/symbol"
    },
    "isDefinedBy" : {
      "@id" : "http://www.w3.org/2000/01/rdf-schema#isDefinedBy",
      "@type" : "@id"
    },
    "label" : {
      "@id" : "http://www.w3.org/2000/01/rdf-schema#label"
    },
    "rdf" : "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
    "owl" : "http://www.w3.org/2002/07/owl#",
    "xsd" : "http://www.w3.org/2001/XMLSchema#",
    "rdfs" : "http://www.w3.org/2000/01/rdf-schema#"
  }
}