Session Date/Time: 25 Feb 2025 16:00

ASDF

Summary

The ASDF Working Group met to discuss updates to draft-ietf-asdf-sdf-core-04 (NIPY) and to progress the digital twin and non-affordance information modeling work. Bart provided an update on NIPY, detailing key changes and the status of the draft text. The main discussion focused on establishing a common understanding and approach for modeling "non-affordance" or "off-device" information, which is crucial for digital twin representations but extends beyond typical device affordances. Participants debated terminology and scope, agreeing to proceed with developing new drafts and examples before finalizing specific terms. Action items were assigned for draft submissions and collaborative document structuring.

Key Discussion Points

SDF Core (NIPY) Draft-04 Status: Bart provided an update on the progress of draft-ietf-asdf-sdf-core-04. Key changes include a new requirement to register both an instance and an SDF interaction model for NIPY operations, and the introduction of a generic protocol map in SDF to define how properties map to specific protocol interactions (e.g., CoAP, MQTT). Ari confirmed the principle of the protocol map is sound and plans to review the draft text once it's integrated into the main branch.
Internet-Draft Publication Best Practices: Carsten emphasized the importance of authors being proactive in submitting internet-drafts, even in formative stages, to allow for earlier and broader community review. He encouraged not striving for "perfection" before initial publication, highlighting that frequent updates are beneficial.
Digital Twin and Non-Affordance Concepts: The discussion delved into the draft-ietf-asdf-digital-twin-00 and the concept of "non-affordance" information.
- Carsten suggested "off-device information" might be a more descriptive term, as the core difference is whether the information is managed by the device or an external entity.
- Two main challenges were identified: (1) identifying the entities managing this off-device information, and (2) defining the structure of this information, which often resembles SDF properties but isn't directly interactable with the device (e.g., a chair's color, a device's serial number if not device-reported, a sensor's room number).
- It was noted that SDF currently supports metadata for events, actions, and properties, but lacks a dedicated category for descriptive metadata of objects or "things" themselves.
- Michael highlighted that digital twins require modeling system-level context and attributes beyond direct device communication.
- Ari proposed viewing digital twin as a specific use case for this type of information, suggesting the core specification for "non-affordance" information should be agnostic and reusable across various contexts.
Relationship to ISO 23247 Part 3: Dr. Hong and Dr. Lee introduced ISO 23247 Part 3 as a relevant external standard for defining relationships and information attributes for digital twins. Dr. Lee, as the project leader, offered to share the FD version of this ISO document with the working group for reference.
Naming for Non-Affordance Information: Participants agreed not to finalize the specific term for this information category (e.g., "non-affordance," "off-device," "attribute") at this stage. It was decided to use "SDF non-affordance" as a placeholder in new drafts and allow more examples and discussion to emerge before settling on a definitive term.
SDF Relations and Digital Twins: Ari observed a potential connection between the current discussion on non-affordance information and the existing SDF Relations draft, suggesting they might represent different facets of a similar underlying concept, with Michael noting his building model examples will leverage SDF relations.

Decisions and Action Items

Decision: The working group will proceed with developing documents related to digital twin and non-affordance information without finalizing the specific terminology (e.g., "non-affordance," "off-device") for now. "SDF non-affordance" will serve as a working placeholder.
Action Item (Bart): Submit draft-ietf-asdf-sdf-core-04 as an Internet-Draft as soon as possible. Alternatively, submit a Pull Request (PR) for the draft text to the main branch of the ASDF GitHub repository for community review.
Action Item (Dr. Lee): Share the FD version of ISO 23247 Part 3 with the ASDF Working Group for reference.
Action Item (Carsten): Read the existing draft-ietf-asdf-digital-twin-00 (which is in XML format), convert it to Markdown, and submit a PR with proposed structural changes to the ASDF GitHub repository.
Action Item (Dr. Hong): Plan and initiate an Internet-Draft for "SDF extensions for non-affordance information."
Action Item (Chair, Michael): Invite Dr. Hong to the ASDF GitHub repository to collaborate on the non-affordance draft.
Action Item (Michael): Create example SDF models that utilize relations to represent digital twins, particularly in the context of building models, to provide concrete use cases for the non-affordance discussion.

Next Steps

Continue the development and review of draft-ietf-asdf-sdf-core-04.
Proceed with the development of the new Internet-Draft for "SDF extensions for non-affordance information" by Dr. Hong.
Review and propose structural improvements for the draft-ietf-asdf-digital-twin-00 document based on Carsten's PR.
The next interim meeting is scheduled for Wednesday, April 9th, at 14:00 UTC.