<?xml version="1.0" encoding="utf-8"?><rdf:RDF  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"  xmlns:skos="http://www.w3.org/2004/02/skos/core#"  xmlns:map="http://www.w3c.rl.ac.uk/2003/11/21-skos-mapping#"  xmlns:dct="http://purl.org/dc/terms/"  xmlns:dc="http://purl.org/dc/elements/1.1/"><skos:ConceptScheme rdf:about="https://digilab.ptb.de/dkd/refType/vocab/">  <dc:title>Metrology Database</dc:title>  <dc:creator>German Calibration Service (DKD)</dc:creator>  <dc:contributor>Thomas Krah, Daniel Hutzschenreuter, Benjamin Gloger, Muhammed-Ali Demir, Moritz Jordan</dc:contributor>  <dc:publisher>Deutscher Kalibrierdienst (German Calibration Service)</dc:publisher>  <dc:rights></dc:rights>  <dc:subject>metrology, reference types, digital calibration certificate, certificate of conformity</dc:subject>  <dc:description><![CDATA[  ]]></dc:description>  <dc:date>2023-06-19</dc:date>  <dct:modified>2026-04-10 06:58:36</dct:modified>  <dc:language>en-US</dc:language>  </skos:ConceptScheme>  <skos:Concept rdf:about="https://digilab.ptb.de/dkd/refType/vocab/skos/536"><skos:prefLabel xml:lang="en-US">PLT</skos:prefLabel> <skos:definition xml:lang="en">Flicker PLT
Long-term perceptibility (PLT). Standardized dimensionless index used to quantify the risk of human annoyance caused by voltage fluctuation (flicker) induced light flicker over a long duration.
Note 1: Long-term perceptibility is measured over a time-interval of 2 hours. </skos:definition> <skos:definition xml:lang="de">Langzeit-Flickerstärke
Long-Term Perceptibility (PLT). Er beschreibt die Wahrnehmbarkeit von Lichtflackern über einen längeren Zeitraum.
Anmerkung: PLT wird über ein Zeitintervall von zwei Stunden ermittelt. </skos:definition> <skos:scopeNote xml:lang="en">Unit: 1 </skos:scopeNote> <skos:scopeNote xml:lang="en">DSI Unit: \one </skos:scopeNote> <skos:scopeNote xml:lang="en">SI Unit: 1 </skos:scopeNote> <skos:historyNote xml:lang="en">2026-04-09 Created </skos:historyNote> <skos:note xml:lang="en">Electropedia (IEC) 161-08-19
IEC 61000-4-15 </skos:note> <skos:example xml:lang="en"> </skos:example><skos:inScheme rdf:resource="https://digilab.ptb.de/dkd/refType/vocab/"/><skos:broader rdf:resource="https://digilab.ptb.de/dkd/refType/vocab/skos/522"/>  <dct:created>2026-04-09 08:27:53</dct:created>  </skos:Concept></rdf:RDF>