AW: [TD] TD Restructuring minutes - 19 October 2016

Please also find attached the presented slides.

Von: Kazuyuki Ashimura [mailto:ashimura@w3.org]
Gesendet: Mittwoch, 19. Oktober 2016 10:42
An: Public Web of Things IG
Betreff: [TD] TD Restructuring minutes - 19 October 2016

available at:
  https://www.w3.org/2016/10/19-wot-td-minutes.html

also as text below.
Thanks a lot for taking these minutes, Taki!
Kazuyuki

---
   [1]W3C

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


                               - DRAFT -

                         WoT - TD Restructuring

19 Oct 2016

   [2]Agenda

      [2] https://lists.w3.org/Archives/Member/member-wot-ig/2016Oct/0013.html


   See also: [3]IRC log

      [3] http://www.w3.org/2016/10/19-wot-td-irc


Attendees

   Present
          Kaz_Ashimura, Victor_Charpenay, Uday_Davuluru,
          Daniel_Peintner, Darko_Anicic, Sebastian_Kaebisch,
          Takuki_Kamiya, Yingying_Chen, Antoine_Zimmermann,
          Achille_Zappa, Maxime_Lefrancois, Katsuyoshi_Naka

   Regrets
   Chair
          Sebastian

   Scribe
          TK

Contents

     * [4]Topics
         1. [5]Agenda
         2. [6]property and actions
         3. [7]Simplified Structure
         4. [8]Naming of encoding
         5. [9]end-point information
         6. [10]Other issues
         7. [11]Resource parameters
         8. [12]Compound property
         9. [13]Separating discussion of requirements from
            serialization formats
     * [14]Summary of Action Items
     * [15]Summary of Resolutions
     __________________________________________________________

   <scribe> scribe: TK

   <scribe> scribeNick: taki

Agenda

   Sebastian: Logistics
   ... Issue discussion
   ... encoding naming, end point information...
   ... then short overview of all issues...
   ... Issues can be registered in GitHub
   ... If there is an issue that can be closed, we close it. If it
   has impact on current practice, then we open a new issue with
   pointer to the original issue.
   ... JSON-LD 1.1. One of the volunteers is not available today.
   He will join the meeting next week.

property and actions

   Sebastian: there are view points...
   ... I added OneM2M viewpoint.
   ... Property has two kind
   ... One is property. static values or no-functional
   information. e.g. serial number.
   ... the other is datapoint. this is dynamic. e.g. temperature.
   ... also for functional information such as target temperature.
   ... All those discussion can be seen in issue 258.
   ... actions are for stateful condition, such as upvolume and
   downvolume.
   ... TD will not have hard rule, this is my impression now.
   ... should be flexible and powerful, and open to solution
   designer and developer.
   ... should be useful for most use cases.

   Kaz: OneM2M classification uses two kind for property.
   ... I personally think this definition is not popular.
   ... Property also can have dynamic value, right?

   Sebastian: Action vs datapoint. Switch on/off - use datapoint.
   ... I picked this information from GitHub discussion Yongjing
   provided.

   Kaz: We can refer to this definition. We should be careful in
   deciding what we do.
   ... Static, variable, combination values, action, state. We
   should be careful about requirement.

   Sebastian: We should be independent.
   ... Already there are existing technologies. Kajimoto san also
   provided use cases.
   ... we need to adapt to those.
   ... We should not stick to one.
   ... We should have flexibility so we can adapt to those
   ... How building blocks are used are up to applications.

   Darko: I am in favor of having flexibility. But we can have
   rules.
   ... I suggest to define some rules as to when to use property,
   for example.
   ... In OneM2M, they have four.

   Sebastian: Property, datapoint, action and event

   Darko: Why do we not want to define similar rules?
   ... People are confused.
   ... Stateful are actions, etc.

   Victor: I read OneM2M.
   ... I could not get good understanding yet.

   Darko: Stateful and stateless. Stateless op is done
   instantaneously. One state to another. Stateful operation is
   not instantaneous. They require memorizing internal or internal
   stage.
   ... Before action is completed, there are states.

   Daniel: To increase volume, you have to know the original
   state.

   Victor: Prior knowledge.
   ... Whether to use property or action is also protocol binding.
   ... You do the operation twice, then volume up happens twice.
   Switch is different.
   ... If we define something not idempotent as property, it is a
   problem.

   Sebastian: We suggest we not have hard rule.
   ... because we should not close doors to some other usages from
   other IoT activities.

   Victor: If two servients have different interpretation, it
   causes problem in interoperability.

   Sebastian: Server always announce what is property.
   ... Developer has choice.
   ... after it is developed, it is clear.

   Darko: This is "Darko's property". This is not the point of
   standard.
   ... We should not be so flexible.

   <achille-z> +1 with Darko

   Darko

   Darko: We should not try to define in hard way, but we should
   define some.

   Victor: Kajimoto-san and Dom also have point of view.

   Sebastian: Property and action discussion is difficult.
   ... victor and darko, please respond to the current outcome.
   ... Today, I tried to reflect current viewpoints.

Simplified Structure

   Sebastian: we introduce @type.
   ... with value property, action, etc.
   ... Property vs action is a big issue that have impact on
   scripting and protocol bindings.

Naming of encoding

   <inserted> [16]Issue-253

     [16] https://github.com/w3c/wot/issues/253


   Sebastian: We are using in the future MIME-Type.
   ... We should also think about "encoding" terminology.
   ... "format", "mediatype", etc

   Daniel: Mediatype is actually used. contenttype is just a field
   in HTTP.

   Victor: I propose to use mediatype.

   Daniel: me too

   Sebastian: If there is no complaint, I would like to select
   that.
   ... I ask them on GitHub.

   Victor: we should close before next telecon?

   <maxime> I just closed it then

   <maxime> comment: Agreed for `mediaType`, which is a term that
   is independent from interaction protocols.

   Sebastian: I will also announce on mailing list.

end-point information

   Sebastian: TD is static about endpoint information, encoding,
   etc.
   ... How can we assign different protocols, etc?

   <kaz> [17]TD examples

     [17] http://w3c.github.io/wot/current-practices/wot-practices.html#quick-start-td-samples


   Sebastian: Events, e.g. only with coap with EXI. somone want to
   provide JPG image as property.
   ... We need to provide local information.
   ... locally defined communication metadata.
   ... We should also keep global definition.
   ... there was such an opinion.

   Kaz: Comment. I am not objecting to the proposal. We need to
   use values defined by IANA registry, correct?

   <kaz> [18]IANA Media Types Registry

     [18] https://www.iana.org/assignments/media-types/media-types.xhtml


   Daniel: correct. "unknown" is ok

   Victor: With "+", we can do more.
   ... specific, your own schema/type.

   <victor>
   [19]https://github.com/vcharpenay/wot/tree/master/proposals/td-

   vs-hydra

     [19] https://github.com/vcharpenay/wot/tree/master/proposals/td-vs-hydra


   Victor: I share a proposal. We need to align two proposal.
   ... Why not keep "href" ?
   ... Each resource that way becomes a link.

   <victor> properties : { hrefs : [ { @id:
   "[20]http://example.org", "mediaType": "application/json" } ] }

     [20] http://example.org/


   Sebastian: TD should be open to OCF's handling of properties.
   ... we can also handle Hydra.

   Victor: We could use endpoint. But we should use "id".

   Sebastian: we have received from google and mozilla about use
   of semantics.

   Victor

   Victor: Hydra is not relevant in the example I gave.
   ... my proposal is to use different key.

   Sebastian: I understand now.
   ... Please make an issue, so we can discuss.

   Victor: ok

   Sebastian: I would like to keep this issue open.

Other issues

   <inserted> [21]Issue-254

     [21] https://github.com/w3c/wot/issues/254


   Sebastian: templates for properties, actions and events

   Darko: with templates, you defined property, I also offer my
   property. In repository, there is a template. The two property
   can have same name. It will enhance interoperability.
   ... It does not cost.
   ... Michael Koster pointed to his proposal.
   ... I would like to propose to use template in our TD
   repository.

   Sebastian: We need this kind of approach. It relates to
   lifecycle.

   Darko: Kajimoto-san's suggestion is based on industry
   experience.
   ... Many things are well-standardized.
   ... My sensor is using existing characteristics.
   ... This is industry practice.

   Sebastian: should we converge this into lifecycle discussion?

   Darko: It can be joined into lifecycle.

Resource parameters

   <inserted> [22]Issue-264

     [22] https://github.com/w3c/wot/issues/264


   Sebastian: Currently there is no definitions.
   ... how parameters are used in resources.
   ... parameters in URL. If you have this kind of REST approach,
   we provide no way to allow for that.

   Sebastian explaining parameter definition ...

   Victor: URL template with parameters.
   ... That's an approach in Hydra.
   ... I will comment in GitHub issue.

Compound property

   <inserted> [23]Issue-256

     [23] https://github.com/w3c/wot/issues/256


   Sebastian: To introduce functionality of grouping.
   ... Please follow the issue.

Separating discussion of requirements from serialization formats

   <kaz> [24]Issue-257

     [24] https://github.com/w3c/wot/issues/257


   Sebastian: Properties vs. action still is an open issue.
   ... Yongjing or Kajimoto-san will join next week.
   ... Talk to you later in regular meeting

   <kaz> [ adjourned ]

Summary of Action Items

Summary of Resolutions

   [End of minutes]
     __________________________________________________________


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