diff --git a/model/content/UsageControlObject.ttl b/model/content/UsageControlObject.ttl
index 68d2314c..90ea4881 100644
--- a/model/content/UsageControlObject.ttl
+++ b/model/content/UsageControlObject.ttl
@@ -18,7 +18,7 @@ ids:UsageControlObject a owl:Class;
            ];
            idsm:validation [
                idsm:forProperty ids:contract;
-               idsm:constraint idsm:NotNull;
+               idsm:constraint idsm:NotEmpty;
                idsm:relationType idsm:OneToMany;
            ] ;
            idsm:validation [
diff --git a/model/contract/Rule.ttl b/model/contract/Rule.ttl
index 4c7a9fcc..0a7f602c 100644
--- a/model/contract/Rule.ttl
+++ b/model/contract/Rule.ttl
@@ -31,7 +31,7 @@ ids:Rule
     idsm:validation [
         idsm:forProperty ids:action;
         idsm:relationType idsm:OneToMany;
-        idsm:constraint idsm:NotNull;
+        idsm:constraint idsm:NotEmpty;
     ].
 
 ids:Permission rdfs:subClassOf ids:Rule;
diff --git a/model/infrastructure/InfrastructureComponent.ttl b/model/infrastructure/InfrastructureComponent.ttl
index 57f40491..76f68eed 100644
--- a/model/infrastructure/InfrastructureComponent.ttl
+++ b/model/infrastructure/InfrastructureComponent.ttl
@@ -25,7 +25,7 @@ ids:InfrastructureComponent rdfs:subClassOf ids:ManagedEntity;
     ];
     idsm:validation [
         idsm:forProperty ids:inboundModelVersion;
-        idsm:constraint idsm:NotNull;
+        idsm:constraint idsm:NotEmpty;
         idsm:relationType idsm:OneToMany;
     ];
     idsm:validation [
@@ -80,4 +80,4 @@ ids:publicKey a owl:ObjectProperty;
     rdfs:label "Public Key"@en;
     rdfs:domain ids:InfrastructureComponent;
     rdfs:range ids:PublicKey;
-    rdfs:comment "Public Key that has been created for the Component."@en.
\ No newline at end of file
+    rdfs:comment "Public Key that has been created for the Component."@en.
diff --git a/model/security/Token.ttl b/model/security/Token.ttl
index d1256204..cc4f35e2 100644
--- a/model/security/Token.ttl
+++ b/model/security/Token.ttl
@@ -72,11 +72,8 @@ ids:JwtPayload a owl:Class ;
     idsm:validation [
         idsm:forProperty ids:transportCertsSha256;
         idsm:relationType idsm:OneToMany;
+        idsm:constraint idsm:NotEmpty;
     ]; 
-    idsm:validation [
-        idsm:forProperty ids:transportCertsSha256;
-        idsm:constraint idsm:NotNull;
-    ]
     .
 
 ids:transportCertsSha256 a owl:DatatypeProperty;