SAREF v3.1.1 is a reference ontology for the IoT developed by ETSI SmartM2M in close interaction with the industry. SAREF contains core concepts that are common to several IoT domains and, to be able to handle specific data elements for a certain domain, dedicated extensions of SAREF have been created, for example SAREF4ENER [[i.4]](#[i.4]), SAREF4ENVI [[i.5]](#[i.5]), SAREF4BLDG [[i.6]](#[i.6]), and SAREF4CITY [[i.7]](#[i.7]), SAREF4INMA [[i.8]](#[i.8]), SAREF4AGRI [[i.9]](#[i.9]). Each domain can have one or more extensions, depending on the complexity of the domain. As a reference ontology, SAREF serves as the means to connect the extensions in different domains. The earlier document ETSI TR 103 411 [[i.10]](#[i.10]) specifies the rationale and methodology used to create, publish and maintain the SAREF extensions.
SAREF v3.1.1 is a reference ontology for the IoT developed by ETSI SmartM2M in close interaction with the industry. SAREF contains core concepts that are common to several IoT domains and, to be able to handle specific data elements for a certain domain, dedicated extensions of SAREF have been created, for example SAREF4ENER [i.4], SAREF4ENVI [i.5], SAREF4BLDG [i.6], and SAREF4CITY [i.7], SAREF4INMA [i.8], SAREF4AGRI [i.9]. Each domain can have one or more extensions, depending on the complexity of the domain. As a reference ontology, SAREF serves as the means to connect the extensions in different domains. The earlier document ETSI TR 103 411 [i.10] specifies the rationale and methodology used to create, publish and maintain the SAREF extensions.
The present document is the technical specification of SAREF4SYST, a generic extension of ETSI TS 103 264 SAREF [[1]](#[1]) that defines an ontology pattern which can be instantiated for different domains. SAREF4SYST defines Systems, Connections between systems, and Connection Points at which systems may be connected. These core concepts can be used generically to define the topology of features of interest, and can be specialized for multiple domains. The topology of features of interest is highly important in many use cases. If a room holds a lighting device, and if it is adjacent with an open window to a room whose luminosity is low, then by turning on the lighting device in the former room one may expect that the luminosity in the latter room will rise.
The present document is the technical specification of SAREF4SYST, a generic extension of ETSI TS 103 264 SAREF [1] that defines an ontology pattern which can be instantiated for different domains. SAREF4SYST defines Systems, Connections between systems, and Connection Points at which systems may be connected. These core concepts can be used generically to define the topology of features of interest, and can be specialized for multiple domains. The topology of features of interest is highly important in many use cases. If a room holds a lighting device, and if it is adjacent with an open window to a room whose luminosity is low, then by turning on the lighting device in the former room one may expect that the luminosity in the latter room will rise.
The SAREF4SYST ontology pattern can be instantiated for different domains. For example to describe zones inside a building (systems), that share a frontier (connections). Properties of systems are typically state variables (e.g. agent population, temperature), whereas properties of connections are typically flows (e.g. heat flow).
@@ -8,7 +8,7 @@ SAREF4SYST has two main aims: on the one hand, to extend SAREF with the capabili
SAREF4SYST consists both of a core ontology, and guidelines to create ontologies following the SAREF4SYST ontology pattern. The core ontology is a lightweight OWL-DL ontology that defines 3 classes and 9 object properties.
Use cases for ontology patterns are described extensively in ETSI TR 103 549 [[i.3]](#[i.3]). Clauses 4.2 and 4.3 extract use cases for the SAREF4SYST ontology pattern.
Use cases for ontology patterns are described extensively in ETSI TR 103 549 [i.3]. Clauses 4.2 and 4.3 extract use cases for the SAREF4SYST ontology pattern.
<p>A graphical overview of the SAREF4SYST ontology is provided in <ahref="#Figure_1">Figure 1</a>. In such figure:</p>
<ul>
• Rectangles are used to denote Classes. The label of the rectangle is the identifier of the Class.
• Plain arrows are used to represent Object Properties between Classes. The label of the arrow is the identifier of the Object Property. The origin of the arrow is the domain Class of the property, and the target of the arrow is the range Class of the property.
• Dashed arrows with identifiers between stereotype signs (i.e. "<<>>") refer to OWL axioms that are applied to some property. Four pairs of properties are inverse one of the other; the property <ahref="#s4syst:connectedTo">s4syst:connectedTo</a> is symmetric, and properties <ahref="#s4syst:hasSubSystem">s4syst:hasSubSystem</a> and <ahref="#s4syst:hasSubSystem">s4syst:hasSubSystem</a> are transitive.
• A symbol =1 near the target of an arrow denotes that the associated property is functional. A symbol ∃ denotes a local existential restriction.
<p>A system may be connected to other systems that are part of its environment. This is modelled by a property named <ahref="#s4syst:connectedTo">s4syst:connectedTo</a>, which is symmetric. </p>
<h3>Connections between systems</h3>
<p>A connection between two <ahref="#s4syst:Systems">s4syst:Systems</a>, modelled by <ahref="#s4syst:connectedTo">s4syst:connectedTo</a>, describes the potential interactions between connected <ahref="#s4syst:Systems">s4syst:Systems</a>. A connection can be qualified using class <ahref="#s4syst:Connection">s4syst:Connection</a>. </p>
<ahref="#Figure_3">Figure 3</a> illustrates classes and properties that can be used to qualify connections between <ahref="#s4syst:Systems">s4syst:Systems</a>.
<figure>
<ahref="diagrams/Connections.png"><imgsrc="diagrams/Connections.png"alt="Connections between systems"/></a>
<figcaptionid="Figure_3">Figure 3: Connections between systems</figcaption>
</figure>
<h3>Connection Points of systems</h3>
<p>A <ahref="#s4syst:System">s4syst:System</a> connects to other <ahref="#s4syst:Systems">s4syst:Systems</a> at connection points. A connection point belongs to one and only one <ahref="#s4syst:System">s4syst:System</a>, and can be described using the class <ahref="#s4syst:ConnectionPoint">s4syst:ConnectionPoint</a>.</p>
<ahref="#Figure_4">Figure 4</a> illustrates the classes and the properties that can be used to describe connection points of a <ahref="#s4syst:System">s4syst:System</a>.
<p>One can then associate a <ahref="#s4syst:ConnectionPoint">s4syst:ConnectionPoint</a> with properties (<ahref="https://saref.etsi.org/core/Property">saref:Property</a>) that describe it (e.g. position and speed, voltage and intensity, thermic transmission coefficient).</p>
<figure>
<ahref="diagrams/ConnectionPoints.png"><imgsrc="diagrams/ConnectionPoints.png"alt="SAREF4SYST: Connection points of systems, where other systems connect"/></a>
<figcaptionid="Figure_4">Figure 4: SAREF4SYST: Connection points of systems, where other systems connect</figcaption>
A graphical overview of the SAREF4SYST ontology is provided in Figure 1. In such figure:
* Rectangles are used to denote Classes. The label of the rectangle is the identifier of the Class.
* Plain arrows are used to represent Object Properties between Classes. The label of the arrow is the identifier of the Object Property. The origin of the arrow is the domain Class of the property, and the target of the arrow is the range Class of the property.
* Dashed arrows with identifiers between stereotype signs (i.e. "<<>>") refer to OWL axioms that are applied to some property. Four pairs of properties are inverse one of the other; the property s4syst:connectedTo is symmetric, and properties s4syst:hasSubSystem and s4syst:hasSubSystem are transitive.
* A symbol =1 near the target of an arrow denotes that the associated property is functional. A symbol ∃ denotes a local existential restriction.
A system may be connected to other systems that are part of its environment. This is modelled by a property named s4syst:connectedTo, which is symmetric.
### Connections between systems
A connection between two s4syst:Systems, modelled by s4syst:connectedTo, describes the potential interactions between connected s4syst:Systems. A connection can be qualified using class s4syst:Connection.
Figure 3 illustrates classes and properties that can be used to qualify connections between s4syst:Systems.
<figure>
<imgsrc="diagrams/Connections.png"alt="Connections between systems"/>
<figcaption>Figure 3: Connections between systems</figcaption>
</figure>
### Connection Points of systems
A s4syst:System connects to other s4syst:Systems at connection points. A connection point belongs to one and only one s4syst:System, and can be described using the class s4syst:ConnectionPoint.
Figure 4 illustrates the classes and the properties that can be used to describe connection points of a s4syst:System.
One can then associate a s4syst:ConnectionPoint with properties (saref:Property) that describe it (e.g. position and speed, voltage and intensity, thermic transmission coefficient).
<figure>
<imgsrc="diagrams/ConnectionPoints.png"alt="SAREF4SYST: Connection points of systems, where other systems connect"/>
<figcaption>Figure 4: SAREF4SYST: Connection points of systems, where other systems connect</figcaption>
