What is an Ontology? [1]
An ontology is a description of a domain. Ontologies can be written in various formats and can be used by computers to reason about the domain they describe. They are also useful as a common format that allows for exchange of knowledge across applications and platforms.
The ontologies for this project are written in OWL 2. OWL 2 is an ontology language that defines the concepts you can use to write an ontology. If you’re not familiar with ontologies, take a few minutes and explore the following links:
What is BACnet? [2]
BACnet - A Data Communication Protocol for Building Automation and Control Networks.
Developed under the auspices of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), BACnet is an American national standard, a European standard, a national standard in more than 30 countries, and an ISO global standard. The protocol is supported and maintained by ASHRAE Standing Standard Project Committee 135.
What is a BACnet Ontology?
A BACnet Ontology treats the contents of the published standard as a model. It has its own lexicon, descriptions of both messages between devices and objects, the properties of which represent the various aspects of the hardware, software, and operation of the device. Most of the standard is described using natural language, some parts are described using ASN.1, but the standard text does not lend itself to formal analysis.
By translating the descriptions of the objects, properties, and communications messages into a formal language like OWL and applying analysis to the result, we hope to provide a cohesive description of the standard that can be incorporated into other formal models.
What is it not?
This is not an electronic version of the standard. The copyright of the standard is held by ASHRAE. You can purchase a copy of the standard by visiting the ASHRAE Bookstore. It is highly recommend, but not required, that you purchase a current copy of the standard if you wish to participate in this project.
This is not a BACnet API. While the descriptions of the communications model match those in the standard, the encoding and decoding rules are not included in this OWL model.
This is not a protocol in a way that systems would use to exchange control system performance or monitoring data, the BACnet protocol is used for that!
This is not another XML format. Descriptions of actual devices (instances of the model) could be exchanged using RDF/XML or one of its other serialzation formats. These descriptions would be conceptually similar to content conveyed using the XML format specified in Annex Q in the 2012 version of the BACnet standard, also known as CSML. This effort has a larger scope because it includes both objects and services, is not tied to a specific serialization format, and existing reasoners and analyzers can be used without first translating the XML content.
This is not a part of the standard. It has no relationship to the activity of the working groups with the SSPC, other than the fact that many of the team members are also involved in working group activity. Many of the team members are also struggling with similar modeling problems in other domains.
Why?
This project was inspired by the opportunity to participate in Ontology Summit 2013 and leverage the tools and expertise of the Ontolog Community and apply them to the design of a machine-interpretable description of BACnet. This effort is in parallel with other efforts to formally model other standards such as the Facility Smart Grid Information Model (FSGIM), which is, in turn, built with references to other standards.
The deliverable of this project, the OWL ontology, is intended to be useful to many other information systems that talk about or include concepts from BACnet.
Footnotes
| [1] | Text inspired from the Introduction to Ontologies with Protege |
| [2] | Text from the BACnet home page |