The .owl file for the ontology can be found here.

You could also download the parametric model and the ontology here.

In this single ontology, the individual ontologies of a Tram Track, a Steel Bridge, a Foot Bridge, a Traffic Dam and a Retaining Wall are combined. The combined Ontology was re-arranged and extended to fit to the integration context. For merging all the systems in one ontology, some axioms within had to be changed and new classes and subclasses as well as their assigned properties were created.

The purpose

The purpose of this ontology integration is to achieve climate policy goals with the combination of tram tracks, steel bridges, pedestrian bridges, traffic dams and retaining walls to create an appropriate transportation framework for both public transport and pedestrians. There were different interfaces between ontologies that were to be combined to one context.

The scope and the users

The concept of public transport uses different technologies. The main scope is to design a reliable, efficient and environmental-friendly tram track system with proper components that benefit different users and enable routes to run through uneven terrains. Those net elements and net relations likebridges, tunnels or traffic dams, play an important part in tramway infrastructures. Typically, transport planning requires a mixture of different technologies to find the best way to adapt to certain environmental conditions. Within the developed ontology different configurations of tram tracks would be possible. However, in this work, the most suitable way to fit the integration context was chosen to combine this tram track with the four other ontologies.

The intended users of the ontology are urban planners, designers as well as civil engineers and architects, who take part in the multi-disciplinary development of regional planning and are responsible for providing better transportation solutions to the people of a city into an urban context.

The modeling process and relations

Combining various ontologies can be difficult due to different names and inconsistencies between their structures. They should be thought again and again and then reanalyzed together to have a proper ontology in the end. Since the five initial systems already had overlaps, they could be logically integrated into one another.

Due to the chosen integration context, the tramway ontology could be used as a starting point. First, the main classes of the tram ontology were assigned to the superclass TramwayInfrastrucuture. All other ontologies could be attached to already existing classes of the tram ontology (compare Figure 1). Among the NetEelements-class of the tram track ontology, a class already existed for bridges over which the tram can run. The whole steel bridge ontology was added to this as a subclass SteelBridge. In the BridgeDomain of the steel bridge ontology there is a class for abutments under BridgeSubstructure. The retaining wall ontology was assigned to this class as a subclass. Since the foot bridge is to function as a crossway over the tram track, a new class Crossways was added in the NetElement-class. Crossways can include bridges, normal crossways or pedestrian tunnels. The foot bridge ontology was than attached to the class of bridges of this new NetElement class. A dam is a direct part of the substrucuture of the tram track system. Under NetRelation -> TrackRelation -> SubstructureElement the existing class embankment was renamed to Dam. The class of the UpperDamLayer and the DamBody from the traffic dam ontology were added as subclasses. Except for the EarthfillMaterial, all other classes of the traffic dam were deleted. The use and also the load classifications were designed for road or railway dams and became unrelevant due to the change of use for a tram line. The structure of the dam in the TrafficDam_Domain overlapped with the super- and substructure classes of the tram track ontology, which is why this class also became redundant. All materials of the individual ontologies were combined in the TramTrackMaterial-class.

Image 1 Combination of the Individual Products into an Overall Ontology

The different design options of the individual system components were implemented in a separate design class for the entire Tramway Infrastructure and the respective design options were newly created. These new individuals of the design options were oriented to the first two options of the parametric model (compare Image 2). The data properties were adapted according to the input parameters selected there. For the tram dam, the distinction between ballasted and slab track was omitted in the TrafficDam_Option, as this should be done in the corresponding TramTrack_Option by assigning the respective track systems and superstructures. The design class of the base courses was added as a sixth system as it is a necessary connecting element between tram track strucuture and the tram dam.

Image 2 Data property hierarchy

Outlook

In the developed ontology, the subclasses of the net elements could be further expanded. In addition to the steel bridge, other bridge types could be provided and the other types of crossways, to which the foot bridge class belongs, can also be considered in more detail. In addition, the possible materials for the base courses should be identified using the EAÖ and added to the material class. The ontology could easily be remodelled for another use, such as railway or road, if the appropriate guidelines are used to edit the ontology. Finally, it could be demonstrated that existing ontologies can be easily merged into a common context. With existing ontologies based on standardised concepts of a specific domain, it should be possible to combine ontologies for different contexts in practice. The work on the ontology has again underlined that a uniform vocabulary for technical terms and a uniform way of class designation would greatly simplify the creation of combined ontologies.

The picture of the final ontology

Image 3 Final Ontology