public QUDG() throws CorruptConfigurationEntryException {
		// only call the first time a QUDG object is created 
		if(! initialized) {
			// speed up by comparing the squared distances (needs not take the square root to get the distance)
			r_min = Configuration.getDoubleParameter("QUDG/rMin");
			r_min_squared = r_min * r_min;

			r_max = Configuration.getDoubleParameter("QUDG/rMax");
			r_max_squared = r_max * r_max;
			
			// Sanity check
			double geomNodeRMax = Configuration.getDoubleParameter("GeometricNodeCollection/rMax");
			if(r_max > geomNodeRMax) { // dangerous! This is probably not what the user wants!
				Main.minorError("WARNING: The maximum transmission range used for the QUDG connectivity model is larger than the maximum transmission range specified for the GeometricNodeCollection.\nAs a result, not all connections will be found! Either fix the problem in the project-specific configuration file or the '-overwrite' command line argument.");
			}
			if(r_max <= r_min) {
				Main.minorError("WARNING: The maximum transmission range used for the QUDG connectivity model is not larger than the minimum tansmission range.\nEither fix the problem in the project-specific configuration file or the '-overwrite' command line argument.");
			}

			// TODO: rewrite the docu of this class
			String type= Configuration.getStringParameter("QUDG/ProbabilityType");
			if(type.toLowerCase().equals("constant")) {
				probabilityType = 0;
				probability =  Configuration.getDoubleParameter("QUDG/connectionProbability");
			} else if(type.toLowerCase().equals("linear")) {
				probabilityType = 1;
				m = 1 / (r_min - r_max);
				q = r_max / (r_max - r_min);
			} else if(type.toLowerCase().equals("quadratic")) {
				probabilityType = 2;
				throw new NotYetImplementedException("QUDG does not yet support quadratic probability distributions.");
			} else {
				// TODO: rewrite the following exception, rewrite docu as well
				throw new CorruptConfigurationEntryException("The QUDG connectivity model requires an entry in the project" +
				" configuration file that specifies the kind of probability to be applied if the distance between two nodes " +
				"lies between rMin and rMax. Possible values for ProbabilityType are 'constant', 'linear', and 'quadratic'.\n\n" +
				"'constant' requires yet another entry 'connectionProbability', which specifies the constant probability at which the connection exists.\n\n" +
				"'linear' applies a linear regression that decreases from 1 to 0 from rMin to rMax.\n\n" +
				"'quadratic' applies a quadratic regression that decreases from 1 to 0 from rMin to rMax.\n\n");
			}
			
			probability =  Configuration.getDoubleParameter("QUDG/connectionProbability");
			initialized = true;
		}
	}