## 6 Validating an Access Management Ontology for Built Environment Cyber Physical System
### Validation on a University Building  
Based on the requirements specification, existing ontological resources and existing non-ontological resources, the access management ontology in smart cities has been developed and validated on two use cases. The university building is a complex use case, with a large mix of individuals that move in and out of the case study dynamically. This includes (a) students, (b) staff, (c) contractors and (d) visitors. This dynamic nature makes it a good case study.  
Smart Parking System: makes it possible for staff and students at a university site to make parking reservations and reveal any campus police violations.  
Attendance Management System: allows university students to register their attendance and staff to keep track of student attendance.  
Figure 3 outlines the classes/properties of the ontology. Due to the large number of classes and properties created and * symbol represents multiplicity, with star indicating any number is valid such as 1, only those from the Smart Parking use case are shown in Figure 3.  
To perform this validation, a test dataset was created based on an existing dataset of the university campus and surrounding facilities to allow this validation to run in a sandbox environment. The steps involved in creating this dataset are as follows:  
* An ontology of the set of surrounding buildings was generated from Open Street Map.
* Ontologies of the university buildings were generated by converting existing IFC models into ifeOWL using commonly available tools.
* Additional data were added manually (extracted from paper-based records) to represent cyber security related information and other metadata that were not present in the BIM datasets. Once the test dataset was constructed, the validation procedure included the following steps:  
1. The ontology will, indeed, be validated to ensure that it sufficiently represents the security needs of the use case chosen.
2. The ontology will be validated to ensure that it accurately assigns and provides access rights to built-environment services. This approach extends beyond authentication to allow users to be granted certain authorizations. Connecting digital identities (authentication) to access control policies applied to various services, all of which are related to real assets in the case of this use case, and all  
Figure 3: Smart parking system access control.  
users are Cardiff University staff or students. However, users connecting with a digital twin could be from any organization and are verified through their own identity suppliers utilizing single sign-on. However, for presentation in this paper, fabricated names are used. Table 3 provides the social information that presents the users of the smart system services.  
Tables 4 and 5 summarize how these use cases are implemented in the ontology and the roles they are granted. Table 5 identifies the policies defined, documenting the decisions that will be taken to allow/deny access to a given service. Table 5 summarizes the overall validation of the ontology. Here, the individual name represents a list of the things that users can do: Reserve University Parking, Record University Parking Violations, Display University Parking Violations. Table 5 also outlines the authorization results made through utilization of the ontology. Therefore, the results in Table 5 show the ontology is functioning as expected.