## 4 The Proposed CIM-Oriented Ontology Database Framework for DMS
### Details of Ontology Database Utilization  
The ODB stores data in RDF files, allowing it to be structured in a subject-predicate-object (S-P-O) format. Since the object-oriented information model used as an interface between components can be directly converted into a database without any transformation, there is no occurrence of object-relational impedance mismatch. The ODB allows for the flexible import and export of data in the CIM/RDF/XML file format. The RDF inference engine, depicted as 'Data Agent' in Figure 11, acts as an interface service connecting the middleware to the ODB. Within the ODB, data are stored in the RDF triple. An ontology for the power network operating system, encompassing the power network, facilities, and operational technology, can be defined. This ontology can be modeled as an information model based on IEC TC57 CIM, and it can be represented in the form of RDF triples. As opposed to an RDB, an ODB does not require a schema design phase because the information model itself represents the database. The information model itself serves as both the schema and payload of the ODB. By utilizing the data agent, it is possible to define and map profiles for the interface between applications, in addition to handling changes in information models. The proposed ODB-based DMS framework can accommodate diverse communication models among system components by flexibly defining CIM-based interface profiles. This aligns with recent studies, such as [31], which emphasize the need for customizable architectures in distributed energy systems to support heterogeneous interaction patterns. Figure 12 shows a portion of the interface schema that is stored in the ODB in the form of S-P-O triples. The schema for the Switch class is defined by inputting 'S', 'P', and 'O' as base:Switch, rdf:type, and rdf:Class, respectively. Since the class name that we want to define is Switch, 'S', 'P', and 'O' are entered as base:Switch, rdfs:label, and \"Switch\"@en, respectively. The comment representing the description of Switch is entered as base:Switch, rdfs:comment, and 'Description of Switch' for S, P, and O, respectively. Since the Switch class is part of the Wires package, 'S', 'P', and 'O' are entered as base:Switch, cims:belongsToCategory, and base:Package_Wires, respectively. As the superclass of  
Figure 10: CIM-oriented DMS development based on MDD and CBD methodologies. Switch is IdentifiedObject, 'S', 'P', and 'O' are entered as base:Switch, rdfs:subClassOf, base:IdentifiedObject, respectively. Figure 13 shows the switch data as part of the payload, stored in the ODB as an S-P-O triple. Since the mRID of the Switch is '10992901066', 'S', 'P', and 'O' are entered as base:10992901066, rdf:type, and cim:Switch, respectively. The value of the attribute IdentifiedObject.aliasName for the object with mRID '10992901066' in Switch is 'Switch4964'. Therefore, 'S', 'P', and 'O' are entered as base:10992901066, cim:IdentifiedObject.aliasName, and \"Switch4964\", respectively. The values of the Switch.locked attribute are set to 'S', 'P', and 'O' with the respective input values of base:10992901066, cim:Switch.locked, and \"false\" because the Switch.locked property is false. The remaining attributes are also stored in the ODB in RDF triple format, following the same method as described above. Figure 11: CIM-oriented DMS using ontology database architecture. Figure 12: An example of storing an interface schema in an ontology database. Data can be exchanged between the ODB and other components in DMS by referring to a defined schema that specifies the syntax in which the syntax of the data to be exchanged is defined and by generating a payload accordingly. The profile intended for transfer from the ODB to other components represents a subset of the complete information model stored in the ODB. The schema for a specific profile can be used as the desired data exchange between components in the form of a payload.