Documentation-of-the-Knowledge-Graph.md

@@ -15,6 +15,9 @@ To simplify the presentation, from now on, we will use a prefixed notation for a
 - @prefix js: <https://www.w3.org/2019/wot/json-schema#> . # JSON schema
 - @prefix onto: <https://ci.mines-stetienne.fr/kg/ontology#> . # Our custom ontology
 - @prefix pto: <http://www.productontology.org/id/> . # The product types ontology
+- @prefix s4sys: <https://saref.etsi.org/saref4syst/> . # SAREF for system ontology
+- @prefix sosa: <http://www.w3.org/ns/sosa/> . # The sensor, observation, sample & actuator ontology
+- @prefix ssn: <http://www.w3.org/ns/ssn/> . # The semantic sensor network ontology
 - @prefix td: <https://www.w3.org/2019/wot/td#> . # Thing Descriptions
 
 The most important parts of the KG are the description of the machines, especially the ones identified as [itm:bosch-apas](https://ci.mines-stetienne.fr/kg/itmfactory/bosch-apas), [itm:dx10](https://ci.mines-stetienne.fr/kg/itmfactory/dx10), [itm:vl10](https://ci.mines-stetienne.fr/kg/itmfactory/vl10), and [itm:xy10](https://ci.mines-stetienne.fr/kg/itmfactory/xy10).
@@ -33,7 +36,7 @@ Moreover, the location of input material or the location of product are features
 
 The production line is described according to the pattern of the figure below:
 
-![production-line-overview.svg](uploads/1ba22c893448c4654d159413bad3977b/production-line-overview.svg)
+![production-line-overview.svg](uploads/b407ccfc0c67937da44a9207a9cdfa3c/production-line-overview.svg)
 
 In practice, the blank nodes will have a specific identifier, and it may be typed with a different class than what is shown in the diagram above. However, a class hierarchy can help inferring that a given entity is of the appropriate type. For instance, here is a piece of the description of the IT'm Factory:
 
@@ -44,5 +47,13 @@ itm:productionLine onto:inputMachine itm:vl10;
    ssn:hasSubSystem itm:dx10;
    ssn:hasSubSystem itm:bosch-apas;
    onto:outputMachine itm:xy10 .
-itm:vl10 a onto:VL10 .
+itm:vl10 a erm:VL10 .
+
+erm:VL10 rdfs:subClassOf onto:PotStorageRack .
 ```
+
+## Connections between subsystems
+
+The four components of the production line are: a storage rack, a filling machine, a robotic arm and a packaging machine. If there exist multiple machines of the same type in the factory, we need to know which one is connected to what. The pattern for describing connections follows the SAREF for System ontology ([SAREF4SYST](https://saref.etsi.org/saref4syst/)). Each machine is a `s4syst:System` that has `s4syst:ConnectionPoint`s. A connection point is attached to a `s4syst:Connection`, which is a physical or virtual entity that represents the connection between 2 systems.
+
+![system_connection.svg](uploads/28858b23e71d2449edb405a0bf6ca1f2/system_connection.svg)
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