[TD-TF] minutes - 8 May 2020

available at:
  https://www.w3.org/2020/05/08-wot-td-minutes.html

also as text.

Thanks a lot for taking the minutes, Victor!

Kazuyuki

---
   [1]W3C

      [1] http://www.w3.org/

                               - DRAFT -

                             WoT-WG - TD-TF

08 May 2020

   [2]Agenda

      [2] https://www.w3.org/WoT/IG/wiki/WG_WoT_Thing_Description_WebConf#May_8.2C_2020

Attendees

   Present
          Kaz_Ashimura, Daniel_Peintner, Ege_Korkan,
          Michael_Koster, Sebastian_Kaebisch, Taki_Kamiya,
          Victor_Charpenay, Tomoaki_Mizushima, Michael_Lagally

   Regrets

   Chair
          Sebastian

   Scribe
          victor

Contents

     * [3]Topics
         1. [4]Prev minutes
         2. [5]Repo logistics
         3. [6]Summary of the WISHI workshop
         4. [7]PR updates
         5. [8]Issues
         6. [9]PlugFest planning
         7. [10]Binding Template
     * [11]Summary of Action Items
     * [12]Summary of Resolutions
     __________________________________________________________

   <inserted> scribenick: victor

Prev minutes

   Sebastian: (goes through the minutes)
   ... can these minutes be published?
   ... no objection

Repo logistics

   <inserted> [13]wot-thing-description top page with TD family

     [13] https://github.com/w3c/wot-thing-description/blob/master/README.md

   Sebastian: new doc, 'feature log'
   ... for each feature: provide author (or issue),TD examples,
   implementations
   ... 2 entries so far (for exemplary purposes), the list will be
   extended

   Daniel: we also have a 'changes' section in the rec. Must the
   content of this new doc be copied into the 'changes'? Can we
   reference this new document instead?

   Kaz: for a first public working draft (status of the next
   version of the TD doc), no need to have a 'changes' section, a
   link to the v1 REC would suffice

   Sebastian: other question about render.sh (render script to
   generate pieces of the spec)
   ... for the REC version of the spec, rendering was disabled.
   Can we have it back?

   Victor: I will have to rewrite the script, it evolved a lot
   over the course of v1 work

   Sebastian: this rendering script generates HTML and graphviz
   graphics. The latter is important.

   Victor: I don't know when I'll be done, maybe you can edit
   index.html manually until the script is rewritten

   Sebastian: would still need the rendering of graphics.

   Victor: ok, it's easier to restore that part.

Summary of the WISHI workshop

   Sebastian: (shows slides he presented at the workshop on TDTs)

   <Ege>
   [14]https://www.iana.org/assignments/link-relations/link-relati
   ons.xhtml

     [14] https://www.iana.org/assignments/link-relations/link-relations.xhtml

   Sebastian: meeting next week with Michael Koster for the next
   WISHI workshop
   ... note copyright/license should be terms that we add to next
   TD version
   ... I'll have to ask Ari where the slides have gone on the
   WISHI Github repo
   ... meeting minutes are also available on the repo

PR updates

   Sebastian: created a PR for JSON schema terms
   ([15]https://github.com/w3c/wot-thing-description/pull/896)
   ... waiting for rendering to be restored to close this PR

     [15] https://github.com/w3c/wot-thing-description/pull/896)

Issues

   Sebastian:
   [16]https://github.com/w3c/wot-thing-description/issues/892
   ... how to get events from the past?
   ... issue creator wishes to have the same feature as Mozilla
   WebThings

     [16] https://github.com/w3c/wot-thing-description/issues/892

   Ege: different types of events being targeted between TD
   (regular events) and Mozilla WebThings (rare events)
   ... suggested a property affordance but seems not to be well
   received

   Koster: the question is how to expose event objects in a
   RESTful way. Two options: expose them as a property or create a
   new op type like 'retrieve event'.
   ... we should collect requirements for this use case.

   Sebastian: should we add this use case to the WoT architecture
   spec?

   <Ege_> Should we also consider property values that have been
   emitted as an observed properties

   Ege: we should probably include in the discussion the question
   of 'observe property'

   Lagally: the topic also relates to the problem of clock
   synchronization

   <kaz> +1

   Victor: I would expect the problem to be addressed at a lower
   level (e.g. timslotted exchange of IP frames)

   Sebastian: agreement on starting describing the use case of
   historical data/events (and defer decisions on TD design after
   we have it)?
   ... issue to create on the arch repo

   Koster: this use case could be integrated to the smart home use
   case

   Lagally: but it also applies to other domains (manufacturing,
   for instance)

   Kaz: also smart city (mentioned by Singapore), transportation
   (mentioned by Zoltan); it is more a category?
   ... should we change the template to include categories?

   Lagally: templates already have categories for applications,
   there could be one for 'historical data'.

   Sebastian: next issue,
   [17]https://github.com/w3c/wot-thing-description/issues/898
   ... terms in Vorto templates to combine different templates,
   have inheritance, etc
   ... what are the equivalent constructs in RDF?

     [17] https://github.com/w3c/wot-thing-description/issues/898

   Victor: about 'multiple', it seems this is information that
   would usually be part of a Web ontology

   Sebastian: not sure about 'breakable', is it specific to TDTs
   or an extension of the general TD model?

   Victor: and for 'extension', there can be conflicts if we allow
   arbitrary extension, we'd need to specify how to resolve them

   Daniel: Kevin (working on Vorto) mentioned they have some
   implementation for extension that can detect some conflicts

   Sebastian: we'll ask Kevin when he's back
   ... next issue,
   [18]https://github.com/w3c/wot-thing-description/issues/897

     [18] https://github.com/w3c/wot-thing-description/issues/897

   <Ege_> Vue.js also uses {{ }}

   <Ege_> [19]https://vuejs.org/v2/guide/syntax.html

     [19] https://vuejs.org/v2/guide/syntax.html

   Lagally: I see a difference between "templates" (pattern
   replacement) and "classes", which we can combine, instantiate
   into TDs, etc

   Sebastian: can you provide examples on how Oracle is defining
   its own "TDTs (DeviceModels)"?

   Lagally: I'll create a presentation, next week or the week
   after

PlugFest planning

   Sebastian: what features should we test?
   ... (in our next PlugFest)
   ... proposal so far is to request the state of an invoked
   action
   ... see
   [20]https://github.com/w3c/wot-thing-description/issues/302
   ... proposal is to have a 'hypermedia' key to know in what JSON
   key to find the link to the handle resource
   ... but we don't know what the response looks like, still

     [20] https://github.com/w3c/wot-thing-description/issues/302

   Koster: old idea of returning parts of a TD to expose all this
   information

   Victor: first comment in that sense of from Matthias Kovatsch,
   in this issue

   Koster: we are still missing a way to indicate where to find a
   link in a JSON response, though (see Sebastian's proposal)

   Victor: initial ideas about that in the HTML documentation of
   the JSON Schema vocabulary (e.g.
   [21]https://www.w3.org/2019/wot/json-schema#defining-a-json-ld-
   context-for-data-instances)
   ... I'll create a new issue to have a discussion specifically
   on these aspects

     [21] https://www.w3.org/2019/wot/json-schema#defining-a-json-ld-context-for-data-instances)

   Sebastian: other topics for the PlugFest?

   Ege: eventing with complex events

   Sebastian: right. One example in the REC, WebhookThing

   <kaz> [22]Example 35

     [22] https://www.w3.org/TR/wot-thing-description/#example-35-temperature-event-with-subscription-and-cancellation

   Ege: the example is complicated and it tries to define the
   Webhook "protocol" in a TD

   Lagally: to me, it is not a protocol but a state machine, a
   state model

   Victor: looks related to the earlier discussion about action
   cancellation/update to me

   Koster: common idea of a "subscription" but still a distinct
   discussion

   Ege: looks to me that we can just refer to Webhook as a
   subprotocol. Question: is there just one Webhook interaction
   pattern or can there be variants?

   Sebastian: seems we don't have many answers yet regarding
   eventing. How about not including it yet in the PlugFest?

   Kaz: other subject for PlugFest is discovery, so we might want
   to think about how to get "id" for specific use case scenarios
   (as well as TD feature testing)

   Sebastian: end of the meeting, we'll have to postpone the
   discussion. To the next PlugFest call?

   <Ege_> I need to leave now though, I have another meeting. Can
   we allocate more time for this next time in case it is not
   finished?

Binding Template

   Victor: created Turtle and HTML files for CoAP and MQTT
   vocabularies
   ... requires review

   <kaz> [adjourned]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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Received on Tuesday, 19 May 2020 22:57:55 UTC