-
11. Digital twins for building and construction
-
11.1 Two parallel initiatives
There are two parallel initiatives with similar scope:
- International Building Performance & Data Initiative (IBPDI) (see section 10.2), which is part of Microsoft’s Open Data Initiative, and which builds upon the Microsoft Common Data Model;
- Real Estate Core ontology (see section 10.3), which is part of Microsoft’s Azure Digital Twin initiative, and which builds upon existing W3C ontologies for building and building systems.
The IBPDI is still at an early stage of development, and there is little beyond the Microsoft Common Data Model beyond scope statements. The Real Estate Core Ontology exists and is expressed in RDF/OWL.
Both initiatives are intended to define software interfaces using JSON. However in the case of the Real Estate Core, the JSON is derived from a formal ontology, which is extensible and can support other implementations. The IBPDI initiative does not yet have any comparable high-level structures to give an overall design.
11.2 International Building Performance & Data Initiative
11.2.1 Defining organization
The International Building Performance & Data Initiative (IBPDI) is a consortium that consists of:
- Microsoft;
- RICS (Royal Institution of Chartered Surveyors);
- BuildingMinds: a German consultancy which has developed a common data model for the real estate industry;
- pom+: a Swiss consultancy in building and construction.
11.2.2 Objectives and scope
The IBPDI “about” web page says:
“The integration of a Common Data Model with international building performance and operations standards […] results in […] consistency and coherence of industry-related data, enabling
- Benchmarking according to international standards
- The integration of industry-specific KPIs from occupant satisfaction, to sustainability to finance KPIs
- Machine learning and artificial intelligence for data-driven insights”
The IBPDI is a new initiative, which held a virtual launch event on the 24th November 2020.
11.2.3 Structure of the model
As a new initiative, there is no detail about the IBPDI model on its web site. However the BuildingMinds web site contains a description of its “Common data model for real estate” at https://buildingminds.com/articles/how-the-common-data-model-can-drive-the-next-level-real-estate/ . This model will be used by the IBPDI. Full details of the model are not given, but the scope is shown by the diagram reproduced here as Figure 1.
Figure 1 - The BuildingMinds Common data model for real estate
The Common data model for real estate is an extension of the Microsoft Common Data Model - an “industry accelerator” in the Microsoft jargon. The Microsoft Common Data Model is part of the “Open Data Initiative” of Microsoft, SAP and Adobe. The Microsoft Common Data Model is publicly available, with a brief description at https://docs.microsoft.com/en-us/common-data-model/ . The scope of the Common Data Model is shown by the diagram reproduced here as Figure 2.
Figure 2 - The Microsoft Common data model
The schemas for the Microsoft Common Data Model are expressed in JSON, and are available at https://github.com/microsoft/CDM .
The model is large, so to give a “flavour” of the approach, the attributes of two entities are as follows:
Article: Structured content that is part of the knowledge base.
Attribute
Description
Article
Shows the ID of the article.
Base Template
Choose the template that you want to use as a base for creating the new article.
Organization
Unique identifier of the organization associated with the article.
Subject
Choose the subject of the article to assist with article searches. You can configure subjects under Business Management in the Settings area.
Article XML
Shows the article content and formatting, stored as XML.
Title
Type a subject or descriptive name for the article to assist with article searches.
Number
Knowledge base article number.
Content
Description of the content of the knowledge base article.
Description
Type additional information that describes the knowledge base article.
Comments
Comments regarding the knowledge base article.
Created On
Date and time when the knowledge base article was created.
Created By
Unique identifier of the user who created the knowledge base article.
Modified By
Unique identifier of the user who last modified the knowledge base article.
Modified On
Date and time when the knowledge base article was last modified.
Status
Shows whether the knowledge base article is in draft, unapproved, or published status. Published articles are read-only and can't be edited unless they are unpublished.
Status Reason
Select the article's status.
Title
Title of the knowledge base article.
Key Words
Keywords to be used for searches in knowledge base articles.
Import Sequence Number
Unique identifier of the data import or data migration that created this record.
Record Created On
Date and time that the record was migrated.
Created By (Delegate)
Unique identifier of the delegate user who created the article.
Modified By (Delegate)
Unique identifier of the delegate user who last modified the kbarticle.
Language
Select which language the article must be available in. This list is based on the list of language packs that are installed in your Microsoft Dynamics 365 environment.
Exchange Rate
Shows the conversion rate of the record's currency. The exchange rate is used to convert all money fields in the record from the local currency to the system's default currency.
Currency
Choose the local currency for the record to make sure budgets are reported in the correct currency.
Entity Image Id
For internal use only.
NOTE 1 From the documentation, it is unclear exactly what an “article” is. From the context it is probably an item in a catalogue of things for sale.
NOTE 2 The duplicate attributes “Title” are in the original.
Currency: Currency in which a financial transaction is carried out.
Attribute
Description
Status Reason
Reason for the status of the transaction currency.
Modified On
Date and time when the transaction currency was last modified.
Status
Status of the transaction currency.
Version Number
Version number of the transaction currency.
Modified By
Unique identifier of the user who last modified the transaction currency.
Import Sequence Number
Unique identifier of the data import or data migration that created this record.
Record Created On
Date and time that the record was migrated.
Created On
Date and time when the transaction currency was created.
Transaction Currency
Unique identifier of the transaction currency.
Exchange Rate
Exchange rate between the transaction currency and the base currency.
Currency Symbol
Symbol for the transaction currency.
Currency Name
Name of the transaction currency.
User
Unique identifier of the user who created the transaction currency.
Currency Code
ISO currency code for the transaction currency.
Organization
Unique identifier of the organization associated with the transaction currency.
Currency Precision
Number of decimal places that can be used for currency.
Created By (Delegate)
Unique identifier of the delegate user who created the transactioncurrency.
Modified By (Delegate)
Unique identifier of the delegate user who last modified the transactioncurrency.
Entity Image Id
For internal use only.
The attribute and entity names are those specified in the JSON, and the descriptions are taken from the JSON [all typos are in the original].
11.2.4 Documentation
The IBPDI project has not yet produced any deliverables. The BuildingMinds Common data model for real estate is not publicly available.
The Microsoft Common Data Model is publicly available, but seems to be documented only by the JSON, with no intermediate level of description between the one-page scoping diagram and the code. The attribute descriptions shown above are not easy to understand outside the context of software development.
The Microsoft Common Data Model is an implementation model which prescribes a particular implementation approach.
11.2.5 Maintenance and usage
IBPDI has no deliverables yet.
The maintenance and usage of the BuildingMinds Common data model for real estate is unknown.
The Microsoft Common Data Model is actively maintained and widely used.
-
11.3 Real Estate Core ontology
11.3.1 Defining organization
The Real estate core ontology is defined by a consortium consisting of:
- Microsoft
- RealEstateCore; and
- Willow, which is a software house specialising in digital twins for systems within buildings.
RealEstateCore is a Swedish consortium of property owners and the School of Engineering at Jönköping University.
11.3.2 Objectives and scope
The Microsoft introduction to the “Smart Building Real Estate Core ontology” says that it will “enhance interoperability and extensibility of your smart building solutions and the reusability of your code”. The introduction gives the overview of the scope shown as Figure 3.
Figure 3 - Scope of the RealEstateCore ontology
The Real Estate Core ontology is implemented in JSON within Microsoft’s “Azure Digital Twins” environment, and documented at https://github.com/azure/opendigitaltwins-building .
The documentation contains the example of use, shown as Figure 4.
Figure 4 - Example of use of the RealEstateCore ontology
Both the Real Estate Core ontology and the International Building Performance & Data Initiative (see section 10.2) are within Microsoft’s “Azure Digital Twins” environment and implemented in JSON. However, Real Estate Core exists also as a formal ontology, expressed in RDF/OWL.
The Real Estate Core ontology builds upon the like BRICK ontology (see section 3.3), W3C Building Topology Ontology (see section 3.4), and the OpenGIS geoSPARQL ontology (see section 4.1).
The Real Estate Core ontology has the following component ontologies:
actuation: This includes south- and northbound message syntaxes for requesting and enacting actuation on building systems of various types, and the interfaces/payload schemas associated with such systems.
agents: work-in-progress
analytics: vocabulary for describing prognoses and aggregates, and the processes used to generate these.
asset: equipment that can be mounted in a building, e.g., HVAC systems, electrical systems, plumbing, alarms, computer networks, etc..
building: building components and rooms.
business: business processes, business relations, etc.
core: the top-level classes and properties that span over or are reused within multiple REC modules.
data schemas: primitive and complex (object/array) data schemas for sensors, actuators, services, etc..
device: device types (sensors and actuators), device configuration, device actuation, etc..
metadata: translation of various metadata schemas, e.g. Dublin Core, into OWL annotation properties.
The schemas can be loaded into Protégé. Screenshots showing the building and asset schemas are shown as Figure 5, Figure 6 and Figure 7.
Figure 5 - Real Estate Core building classes
Figure 6 - Real Estate Core asset classes
Figure 7 - Real Estate Core asset properties
Mostly the ontology is to best practice. A minor quibble is that in a few cases, subclasses are indicated by string attributes, as shown in Figure 8.
Figure 8 - Real Estate Core subclass as datatype
11.2.4 Documentation
The JSON implementation for the Real Estate Core is principally documented by its derivation from the RDF/OWL ontology. This ontology is well documented using W3C standards, and is clear and easily understood.
11.2.5 Maintenance and usage
The level of use is unclear. On a web page dated 23rd September 2020, the Willow company talks about implementing the Real Estate Core as an opportunity for the future.
The Real Estate Core ontology is actively maintained with the latest release 3.3 dated June 2020. The technical work is lead by Karl Hammar of the School of Engineering at Jönköping University.
