Adding default value to output directory

benchmark.ttl

@@ -79,7 +79,8 @@ bench:hasMimickingOutput	a		hobbit:Parameter, hobbit:FeatureParameter, hobbit:Co
 				rdfs:label	"Name of mimicking algorithm output folder"@en;
 				rdfs:comment	"The mimicking algorithm output folder used to store the data generated from a mimicing algorithm."@en;
 				rdfs:domain	hobbit:Experiment, hobbit:Challenge;
-				rdfs:range	xsd:string.
+				rdfs:range	xsd:string;
+				hobbit:defaultValue "output_data/"^^xsd:string.
 
 bench:hasNumberOfInsertQueries	a		hobbit:Parameter, hobbit:FeatureParameter, hobbit:ConfigurableParameter;
 				rdfs:label	"Number of insert queries"@en;