public static OntClass getSensorClassUsingObservedPhysicalQuantity(String observedPhysicalQuantity){
		
		OntClass observingSensorClass = null;
		Property propertyObserves = aceCore.getProperty(iriSSNObserves);
		OntClass sensorOntClass = aceCore.getOntologyClass(iriSSNSensor);
		boolean foundClass = false;
		for(ExtendedIterator<OntClass> i = sensorOntClass.listEquivalentClasses();i.hasNext();)
		{
			OntClass equivalentSensorClass = i.next();
			if(equivalentSensorClass.getURI().equals(iriSSNSensor))
			{
				continue;
			}
			for(ExtendedIterator<OntClass> j = equivalentSensorClass.listSuperClasses();j.hasNext();)
			{
				OntClass sup = j.next();
				if(sup.isRestriction())
				{
					Restriction r = sup.asRestriction();
					if(r.getOnProperty().equals(propertyObserves))
					{
						HasValueRestriction hvr = r.asHasValueRestriction();
						RDFNode hvrValue = hvr.getHasValue();
						if(null != hvrValue && hvrValue.asResource().getURI().equals(observedPhysicalQuantity))
						{
							observingSensorClass = equivalentSensorClass;
							foundClass = true;
							break;
						}
					}
					
				}
			}
			
			if(true == foundClass)
				break;
		}
		return observingSensorClass;
	}