W3C

– DRAFT –
Web-based Digital Twins for Smart Cities IG

07 July 2025

Attendees

Present
Kaz_Ashimura, Kunihiko_Toumura, Mark_Fox, Michael_Koster, Tomoaki_Mizushima, Torbjorn_Lahrin
Regrets
-
Chair
Koster
Scribe
kaz

Meeting minutes

Guests

Kaz: we have Mark today as well :)

Minutes

May-26

Koster: (goes through the minutes)
… any changes?

(none)

approved

PRs

PR 8

PR 8 - Update technology-categories.md

Koster: (goes through the changes)

Kaz: based on the discussion in May
… have put two major categories
… digital twin framework and vocabulary
… then put the existing contents under those categories

Koster: nothing controversial :)

Kaz: right
… let's merge this PR
… and then continue our discussion on the existing resources

Koster: ok
… any objections?

(none)

merged

Discussion on the resources

Kaz: Mark mentioned in May that he was working with his students on survey around vocabularies
… would see which part can be published and which part can be put here on the resources.md and categories.md

Mark: so far, what I see is a set of categories is more smart city oriented
… major services for smart cities are also worked by ISO/IEC
… transportation, water and public safety, etc.
… it depends on what you want
… organizations, companies, etc.
… vocabularies and ontologies of those contexts for various services
… e.g., transportation ontology a few years ago
… water sanitization as well
… land zoning
… building
… section of services for smart cities in general

Kaz: tx a lot for your thoughtful comments!

Koster: like Brick and Real Estate Core
… how should we proceed?

Kaz: yeah
… the resources.md is getting messy
… so would suggest we add those major services and ontologies for smart cities to the technology-categories.md instead

Koster: how to deal with the existing contents?

Mark: entity/relationship data is OK to be under vocabularies
… but would be better to have another category like sensor data for "Time series and measurements"
… I can show some diagram about the structure

Koster: tx!
… good to clarify the basic layers also

Mark: (shows the ontology stack diagram)
… service level, city level and foundation level
… foundation level has activity, agreement, agent, city units, change, general properties, location, mereology, organization structure, provenance, recurring event, resource and time
… city level has building, bylaw, city, contact, contract, household, indicator, infrastructure, land use, person, organization, resident, sensors, service
… service level has transport network, road network, rail network, micromobility networ, pedestrian network, travel corridor, public transport system, transport alert; public health vent, desease, person, medical resource, resource logistics, etc.

Koster: are they already standardized?

Mark: some of them are already standards
… and some of them are getting standards
… (then shows examples)

ISO/IEC 5087-2 Information technology - City data model — Part 2: City level concepts

Koster: wondering who is using what

Mark: good question

Koster: looks a lot of work is done
… there are RDF-Star and NGSI-LD also
… should look into information model also
… what to be done to create an interoperable framework for smart cities?
… obviously shouldn't start with creating something from scratch

Mark: it's difficult to answer
… there is not a single place for everything
… always motivated by people's interest
… some work done for city and we could look into several papers
… give me a sec...
… (shows ISO/IEC 5087-2)
… the Appendix has resources

Kaz: thanks! really useful
… but do we need to pay for this document?

Mark: need to pay for this document itself
… but don't need to pay for our implementation :)

Kaz: it seems the ISO/IEC site is not publicly available...
… can we refer to your GitHub repo instead?

Household Ontology on GitHub

Mark: yes, the primary resource is managed on the ISO/IEC site but you can refer to the GitHub also
… that is our work area
… the diagram I showed describes the basic architecture of the ontologies
… but it depends on what you need

Koster: yeah, makes sense
… what to be implemented and information model to be clarified
… actual service you need
… starts getting more specific

Mark: to me, the key adjective here is "Web-based"
… also important to have the phrase "Digital Twins" in front of "Smart Cities"
… wondering what "Web-based" here really means

Kaz: we added "Web-based" mainly because we wanted to start with Web standards
… what to be extended for Web standards is the key question here

Koster: yeah, for example, Web of Things is a Web standard for digital twins
… we're still scoping as an Interest Group

Kaz: we're getting out of time, but thank you very much for your input, Mark! your advice is always really helpful.

Mark: think you need to understand multi agents for the Web as well

Koster: right

Kaz: indeed
… actually, that's why we're organizing yet another W3C workshop on smart agents :)

Koster: let's wrap up the discussion
… need to think about what "Web-based" means for Smart Cities and Digital Twins

Next meeting

Kaz: will organize another Doodle poll to accommodate Mark and Torbjorn

Koster: ok
… the meeting adjourned for today

[adjourned]

Minutes manually created (not a transcript), formatted by scribe.perl version 244 (Thu Feb 27 01:23:09 2025 UTC).