RDF Working Group Teleconference

Minutes of 01 February 2012

Seen
Alex Hall, Andy Seaborne, Arnaud Le Hors, David Wood, Eric Prud'hommeaux, Gavin Carothers, Ivan Herman, Lee Feigenbaum, Nicholas Humfrey, Patrick Hayes, Peter Patel-Schneider, Sandro Hawke, Souripriya Das, Steve Harris, Ted Thibodeau, Zhe Wu
Scribe
Alex Hall
IRC Log
Original and Editable Wiki Version
Resolutions
  1. accept the minutes of the 25 Jan telecon link
  2. to close ISSUE-79 http://www.w3.org/2011/rdf-wg/track/issues/79 link
Topics
16:01:57 <RRSAgent> logging to http://www.w3.org/2012/02/01-rdf-wg-irc

RRSAgent IRC Bot: logging to http://www.w3.org/2012/02/01-rdf-wg-irc

16:01:59 <trackbot> RRSAgent, make logs world

Trackbot IRC Bot: RRSAgent, make logs world

16:02:01 <trackbot> Zakim, this will be 73394

Trackbot IRC Bot: Zakim, this will be 73394

16:02:01 <Zakim> ok, trackbot; I see SW_RDFWG()11:00AM scheduled to start 2 minutes ago

Zakim IRC Bot: ok, trackbot; I see SW_RDFWG()11:00AM scheduled to start 2 minutes ago

16:02:02 <trackbot> Meeting: RDF Working Group Teleconference
16:02:02 <trackbot> Date: 01 February 2012
16:02:11 <ivan> zakim, who is on the phone?

Ivan Herman: zakim, who is on the phone?

16:02:15 <Zakim> SW_RDFWG()11:00AM has not yet started, ivan

Zakim IRC Bot: SW_RDFWG()11:00AM has not yet started, ivan

16:02:19 <Zakim> On IRC I see RRSAgent, MacTed, AlexHall, gavinc, Arnaud, AZ, pfps, swh, AndyS, LeeF, mischat, ivan, SteveH, danbri, mdmdm, manu1, davidwood, yvesr, NickH, trackbot, manu, sandro,

Zakim IRC Bot: On IRC I see RRSAgent, MacTed, AlexHall, gavinc, Arnaud, AZ, pfps, swh, AndyS, LeeF, mischat, ivan, SteveH, danbri, mdmdm, manu1, davidwood, yvesr, NickH, trackbot, manu, sandro,

16:02:22 <Zakim> ... ericP

Zakim IRC Bot: ... ericP

16:02:23 <ivan> zakim, dial ivan-voip

Ivan Herman: zakim, dial ivan-voip

16:02:28 <Zakim> ok, ivan; the call is being made

Zakim IRC Bot: ok, ivan; the call is being made

16:02:57 <MacTed> Zakim, this is 73394

Ted Thibodeau: Zakim, this is 73394

16:02:58 <Zakim> ok, MacTed; that matches SW_RDFWG()11:00AM

Zakim IRC Bot: ok, MacTed; that matches SW_RDFWG()11:00AM

16:02:59 <MacTed> Zakim, who's here?

Ted Thibodeau: Zakim, who's here?

16:02:59 <Zakim> On the phone I see Peter_Patel-Schneider, davidwood, AZ, OpenLink_Software, ??P11, AlexHall, Arnaud, gavinc, Ivan, sandro, ??P16, Souri

Zakim IRC Bot: On the phone I see Peter_Patel-Schneider, davidwood, AZ, OpenLink_Software, ??P11, AlexHall, Arnaud, gavinc, Ivan, sandro, ??P16, Souri

16:03:02 <Zakim> On IRC I see Souri, Zakim, RRSAgent, MacTed, AlexHall, gavinc, Arnaud, AZ, pfps, swh, AndyS, LeeF, mischat, ivan, SteveH, danbri, mdmdm, manu1, davidwood, yvesr, NickH, trackbot,

Zakim IRC Bot: On IRC I see Souri, Zakim, RRSAgent, MacTed, AlexHall, gavinc, Arnaud, AZ, pfps, swh, AndyS, LeeF, mischat, ivan, SteveH, danbri, mdmdm, manu1, davidwood, yvesr, NickH, trackbot,

16:03:04 <Zakim> ... manu, sandro, ericP

Zakim IRC Bot: ... manu, sandro, ericP

16:03:11 <MacTed> Zakim, OpenLink_Software is temporarily me

Ted Thibodeau: Zakim, OpenLink_Software is temporarily me

16:03:12 <AndyS> zakim, ??P11 is me

Andy Seaborne: zakim, ??P11 is me

16:03:12 <swh> Zakim, ??P16 is me

Steve Harris: Zakim, ??P16 is me

16:03:13 <MacTed> Zakim, mute me

Ted Thibodeau: Zakim, mute me

16:03:14 <Zakim> +MacTed; got it

Zakim IRC Bot: +MacTed; got it

16:03:18 <Zakim> +AndyS; got it

Zakim IRC Bot: +AndyS; got it

16:03:20 <Zakim> +swh; got it

Zakim IRC Bot: +swh; got it

16:03:22 <Zakim> MacTed should now be muted

Zakim IRC Bot: MacTed should now be muted

16:03:42 <AlexHall> scribe: alexhall

(Scribe set to Alex Hall)

16:03:47 <davidwood> PROPOSED to accept the minutes of the 25 Jan telecon:

David Wood: PROPOSED to accept the minutes of the 25 Jan telecon:

16:03:47 <davidwood>    http://www.w3.org/2011/rdf-wg/meeting/2012-01-25

David Wood: http://www.w3.org/2011/rdf-wg/meeting/2012-01-25

16:03:51 <AlexHall> topic: admin

1. admin

16:04:02 <davidwood> Action item review:

David Wood: Action item review:

16:04:02 <trackbot> Sorry, couldn't find user - item

Trackbot IRC Bot: Sorry, couldn't find user - item

16:04:02 <davidwood>    http://www.w3.org/2011/rdf-wg/track/actions/pendingreview

David Wood: http://www.w3.org/2011/rdf-wg/track/actions/pendingreview

16:04:02 <davidwood>    http://www.w3.org/2011/rdf-wg/track/actions/open

David Wood: http://www.w3.org/2011/rdf-wg/track/actions/open

16:04:10 <AlexHall> davidwood: no objections, minutes accepted

David Wood: no objections, minutes accepted

16:04:21 <AlexHall> RESOLVED to accept the minutes of the 25 Jan telecon

RESOLVED: accept the minutes of the 25 Jan telecon

16:04:40 <MacTed> Zakim, unmute me

Ted Thibodeau: Zakim, unmute me

16:04:40 <Zakim> MacTed should no longer be muted

Zakim IRC Bot: MacTed should no longer be muted

16:04:44 <Zakim> +LeeF

Zakim IRC Bot: +LeeF

16:04:53 <Zakim> +PatH

Zakim IRC Bot: +PatH

16:05:15 <AlexHall> davidwood: action item reviews

David Wood: action item reviews

16:05:18 <MacTed> s/RESOLVED to accept/RESOLVED: accept/
16:06:04 <AlexHall> davidwood: eric completed his review of XML Schema changes, andy commented, can mark it done

David Wood: eric completed his review of XML Schema changes, andy commented, can mark it done

16:06:28 <AlexHall> davidwood: past-due action items

David Wood: past-due action items

16:06:34 <zwu2> zakim, code?

Zhe Wu: zakim, code?

16:06:34 <Zakim> the conference code is 73394 (tel:+1.617.761.6200 sip:zakim@voip.w3.org), zwu2

Zakim IRC Bot: the conference code is 73394 (tel:+1.617.761.6200 sip:zakim@voip.w3.org), zwu2

16:06:52 <AlexHall> patH: will work on action 120

Patrick Hayes: will work on ACTION-120

16:07:14 <Zakim> +zwu2

Zakim IRC Bot: +zwu2

16:07:28 <zwu2> zakim, mute me

Zhe Wu: zakim, mute me

16:07:28 <Zakim> zwu2 should now be muted

Zakim IRC Bot: zwu2 should now be muted

16:07:37 <AlexHall> davidwood: let's talk about issue 79, what is the value of a datatyped literals whose datatype IRI is not a datatype?

David Wood: let's talk about ISSUE-79, what is the value of a datatyped literals whose datatype IRI is not a datatype?

16:07:41 <davidwood> http://lists.w3.org/Archives/Public/public-rdf-wg/2011Nov/0167.html

David Wood: http://lists.w3.org/Archives/Public/public-rdf-wg/2011Nov/0167.html

16:07:44 <Zakim> +EricP

Zakim IRC Bot: +EricP

16:08:20 <AlexHall> davidwood: cygri mentioned that he's satisfied with changes made to the wording of the spec to address this, per message on the mailing list

David Wood: cygri mentioned that he's satisfied with changes made to the wording of the spec to address this, per message on the mailing list

16:09:26 <AlexHall> patH: prefer the original wording, but this is OK

Patrick Hayes: prefer the original wording, but this is OK

16:09:48 <AlexHall> davidwood: objections to closing issue 79?

David Wood: objections to closing ISSUE-79?

16:09:49 <sandro> issue-79?

Sandro Hawke: ISSUE-79?

16:09:49 <trackbot> ISSUE-79 -- What is the value of a literal whose datatype IRI is not a datatype? -- pending review

Trackbot IRC Bot: ISSUE-79 -- What is the value of a literal whose datatype IRI is not a datatype? -- pending review

16:09:49 <trackbot> http://www.w3.org/2011/rdf-wg/track/issues/79

Trackbot IRC Bot: http://www.w3.org/2011/rdf-wg/track/issues/79

16:09:57 <AlexHall> patH: editorial, not substantive

Patrick Hayes: editorial, not substantive

16:10:05 <davidwood> RESOLVED: to close ISSUE-79 http://www.w3.org/2011/rdf-wg/track/issues/79

RESOLVED: to close ISSUE-79 http://www.w3.org/2011/rdf-wg/track/issues/79

16:10:37 <davidwood> Topic: Revisit XML Schema Datatypes in RDF and OWL?

2. Revisit XML Schema Datatypes in RDF and OWL?

16:11:07 <davidwood> XML Schema Datatypes in RDF and OWL is a W3C Working Group Note dated 14 March 2006:

David Wood: XML Schema Datatypes in RDF and OWL is a W3C Working Group Note dated 14 March 2006:

16:11:07 <davidwood>  http://www.w3.org/TR/swbp-xsch-datatypes/

David Wood: http://www.w3.org/TR/swbp-xsch-datatypes/

16:11:15 <AlexHall> davidwood: cygri brought up that we might need to revisit 2006 wg note on XSD datatypes in RDF and OWL

David Wood: cygri brought up that we might need to revisit 2006 wg note on XSD datatypes in RDF and OWL

16:11:18 <ivan> q+

Ivan Herman: q+

16:11:23 <davidwood> ack ivan

David Wood: ack ivan

16:11:26 <Zakim> +??P34

Zakim IRC Bot: +??P34

16:11:44 <AlexHall> ivan: don't consider that a very high-priority issue

Ivan Herman: don't consider that a very high-priority issue

16:12:01 <NickH> zakim, ??P34 is me

Nicholas Humfrey: zakim, ??P34 is me

16:12:01 <Zakim> +NickH; got it

Zakim IRC Bot: +NickH; got it

16:12:04 <AlexHall> ... wonder if anybody out there actually used the mechanism for defining new XSD datatypes in RDF

... wonder if anybody out there actually used the mechanism for defining new XSD datatypes in RDF

16:12:07 <NickH> Zakim, mute me

Nicholas Humfrey: Zakim, mute me

16:12:07 <Zakim> NickH should now be muted

Zakim IRC Bot: NickH should now be muted

16:12:12 <gavinc> ivan, TQ uses it

Gavin Carothers: ivan, TQ uses it

16:12:15 <MacTed> Zakim, mute me

Ted Thibodeau: Zakim, mute me

16:12:15 <Zakim> MacTed should now be muted

Zakim IRC Bot: MacTed should now be muted

16:12:26 <AlexHall> davidwood: think some XML-heads in large enterprise might have used it

David Wood: think some XML-heads in large enterprise might have used it

16:12:53 <swh> Some talis people use it, but arguably incorrectly

Steve Harris: Some talis people use it, but arguably incorrectly

16:12:54 <gavinc> ivan, used when importing XML schema into RDF

Gavin Carothers: ivan, used when importing XML schema into RDF

16:13:04 <MacTed> Zakim, unmute me

Ted Thibodeau: Zakim, unmute me

16:13:04 <Zakim> MacTed should no longer be muted

Zakim IRC Bot: MacTed should no longer be muted

16:14:15 <AlexHall> macted: can't think of any use off the top of my head, but gut is that yes it has been used

Ted Thibodeau: can't think of any use off the top of my head, but gut is that yes it has been used

16:14:56 <gavinc> q+ Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

Gavin Carothers: q+ Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

16:15:08 <gavinc> q+ to talk about Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

Gavin Carothers: q+ to talk about Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

16:15:32 <AlexHall> ericP: scenario where we need to update the note is that the mechanism for defining literals changed, most likely it's backwards compatible and doesn't need revision

Eric Prud'hommeaux: scenario where we need to update the note is that the mechanism for defining literals changed, most likely it's backwards compatible and doesn't need revision

16:15:44 <davidwood> ack gavinc

David Wood: ack gavinc

16:15:44 <Zakim> gavinc, you wanted to talk about Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

Zakim IRC Bot: gavinc, you wanted to talk about Section 4: http://www.w3.org/TR/swbp-xsch-datatypes/#section-duration needs to change

16:15:55 <AlexHall> patH: willing to look at it from semantics perspective

Patrick Hayes: willing to look at it from semantics perspective

16:16:40 <AlexHall> gavinc: note mentions that duration doesn't have a well-defined value space, should at least revise that part

Gavin Carothers: note mentions that duration doesn't have a well-defined value space, should at least revise that part

16:17:05 <AlexHall> davidwood: think we have an obligation to keep docs up to date, will email jeremy

David Wood: think we have an obligation to keep docs up to date, will email jeremy

16:17:19 <AlexHall> action: davidwood to ask jeremey to review XSD in RDF and OWL note

ACTION: davidwood to ask jeremey to review XSD in RDF and OWL note

16:17:19 <trackbot> Created ACTION-139 - Ask jeremey to review XSD in RDF and OWL note [on David Wood - due 2012-02-08].

Trackbot IRC Bot: Created ACTION-139 - Ask jeremey to review XSD in RDF and OWL note [on David Wood - due 2012-02-08].

16:17:27 <gavinc> Zakim, mute me

Gavin Carothers: Zakim, mute me

16:17:27 <Zakim> gavinc should now be muted

Zakim IRC Bot: gavinc should now be muted

16:17:36 <AlexHall> action: patH to review XSD in RDF and OWL from semantics perspective

ACTION: patH to review XSD in RDF and OWL from semantics perspective

16:17:36 <trackbot> Created ACTION-140 - Review XSD in RDF and OWL from semantics perspective [on Patrick Hayes - due 2012-02-08].

Trackbot IRC Bot: Created ACTION-140 - Review XSD in RDF and OWL from semantics perspective [on Patrick Hayes - due 2012-02-08].

16:17:20 <davidwood> Topic: RDF and Time

3. RDF and Time

16:18:24 <AlexHall> davidwood: while pat is here, would like to talk about RDF and time to try and move forward with named graphs

David Wood: while pat is here, would like to talk about RDF and time to try and move forward with named graphs

16:18:43 <AlexHall> ... pat made point on mailing list that there is no notion of time sensitivity in RDF at all

... pat made point on mailing list that there is no notion of time sensitivity in RDF at all

16:19:10 <AlexHall> ... surprised me that named graphs are so closely related to time variability

... surprised me that named graphs are so closely related to time variability

16:19:26 <sandro> q+

Sandro Hawke: q+

16:19:50 <AlexHall> ... thought that RDF graphs always expressed a snapshot of the world at the time they were written

... thought that RDF graphs always expressed a snapshot of the world at the time they were written

16:20:16 <AlexHall> patH: if you think of RDF that way, it doesn't fit with the semantics

Patrick Hayes: if you think of RDF that way, it doesn't fit with the semantics

16:20:44 <Zakim> -Arnaud

Zakim IRC Bot: -Arnaud

16:20:45 <AlexHall> ... facts in RDF are not time-relative, 2 + 2 = 4 for all of eternity

... facts in RDF are not time-relative, 2 + 2 = 4 for all of eternity

16:21:04 <sandro> pat: RDF is a "timeless" framework, where facts are always true

Patrick Hayes: RDF is a "timeless" framework, where facts are always true [ Scribe Assist by Sandro Hawke ]

16:21:14 <AlexHall> ... if you want to talk about time, you have to explicitly put them in the ontology

... if you want to talk about time, you have to explicitly put them in the ontology

16:21:20 <Zakim> +Arnaud

Zakim IRC Bot: +Arnaud

16:21:37 <sandro> pat: from Aristotle forward, that's how mathematicians have liked to think of it.

Patrick Hayes: from Aristotle forward, that's how mathematicians have liked to think of it. [ Scribe Assist by Sandro Hawke ]

16:21:55 <sandro> pat: or you have have a time-embedded framework, with an implicit "now".

Patrick Hayes: or you have have a time-embedded framework, with an implicit "now". [ Scribe Assist by Sandro Hawke ]

16:21:58 <ericP> pat: in time-embedded, if you say the same thing at different times, it means different things

Patrick Hayes: in time-embedded, if you say the same thing at different times, it means different things [ Scribe Assist by Eric Prud'hommeaux ]

16:22:02 <AlexHall> ... you can also think of facts as time-embedded, saying the same thing at two different times can mean two things

... you can also think of facts as time-embedded, saying the same thing at two different times can mean two things

16:22:15 <sandro> pat: in the second case, the inference rules change.

Patrick Hayes: in the second case, the inference rules change. [ Scribe Assist by Sandro Hawke ]

16:22:15 <ericP> ... so you have to incorporate that context into the semantics

Eric Prud'hommeaux: ... so you have to incorporate that context into the semantics

16:22:28 <AlexHall> ... it's natural to think that way, but it complicates the logic when time is implicit in the graph

... it's natural to think that way, but it complicates the logic when time is implicit in the graph

16:22:52 <sandro> pat: so the question is whether RDF is timeless or time-embedded.    It's not possible to prevent people from using it in a time-embedded way because that's how people think of this.

Patrick Hayes: so the question is whether RDF is timeless or time-embedded. It's not possible to prevent people from using it in a time-embedded way because that's how people think of this. [ Scribe Assist by Sandro Hawke ]

16:22:58 <AlexHall> ... impossible to prevent people from using RDF in a time-embedded way

... impossible to prevent people from using RDF in a time-embedded way

16:22:59 <sandro> q-

Sandro Hawke: q-

16:23:42 <sandro> eric: Do have to say, "as of this date, our understanding is, this protein has these properties..."

Eric Prud'hommeaux: Do have to say, "as of this date, our understanding is, this protein has these properties..." [ Scribe Assist by Sandro Hawke ]

16:24:35 <AlexHall> patH: scale is important; if data is expected to change over the course of the time that the data is used, then you need to account for time

Patrick Hayes: scale is important; if data is expected to change over the course of the time that the data is used, then you need to account for time

16:24:54 <sandro> eric: So they differ in degree -- time range of things changing -- not actually in kind.

Eric Prud'hommeaux: So they differ in degree -- time range of things changing -- not actually in kind. [ Scribe Assist by Sandro Hawke ]

16:25:12 <AlexHall> patH: e.g. weather report for this week vs. geologic time scales

Patrick Hayes: e.g. weather report for this week vs. geologic time scales

16:25:38 <sandro> ted: One might expect that HTTP caching and expiration mechanism could be used to help with this.

Ted Thibodeau: One might expect that HTTP caching and expiration mechanism could be used to help with this. [ Scribe Assist by Sandro Hawke ]

16:26:23 <Arnaud> given that time sensitivity is really dependent on the type of data you're dealing with isn't that better left to the application?

Arnaud Le Hors: given that time sensitivity is really dependent on the type of data you're dealing with isn't that better left to the application?

16:26:33 <AlexHall> patH: expect that this conversation is going to arrive at the point where we have to acknowledge that people use RDF in a time-embedded way

Patrick Hayes: expect that this conversation is going to arrive at the point where we have to acknowledge that people use RDF in a time-embedded way

16:27:01 <sandro> davidwood: Our charter gives us use cases that need this to be address to solve them....

David Wood: Our charter gives us use cases that need this to be address to solve them.... [ Scribe Assist by Sandro Hawke ]

16:27:49 <AlexHall> david: Find this to be the heart of the problem, that named graphs are very closely tied to provenance which is how time sensitivity is addressed

David Wood: Find this to be the heart of the problem, that named graphs are very closely tied to provenance which is how time sensitivity is addressed

16:28:25 <AlexHall> patH: one approach is to say that the modelers are always going to have to account for time in their data

Patrick Hayes: one approach is to say that the modelers are always going to have to account for time in their data

16:28:49 <AlexHall> ... but modelers aren't going to do that because it's hard and unnatural

... but modelers aren't going to do that because it's hard and unnatural

16:28:54 <sandro> q+

Sandro Hawke: q+

16:29:01 <davidwood> ack sandro

David Wood: ack sandro

16:29:07 <AlexHall> david: also affects versioning and merging of graphs created at different times

David Wood: also affects versioning and merging of graphs created at different times

16:29:48 <AlexHall> patH: true, time information has to be captured to effectively merge datasets where time is implicit

Patrick Hayes: true, time information has to be captured to effectively merge datasets where time is implicit

16:29:57 <patH> peter, I never saw you as a tosser.

Patrick Hayes: peter, I never saw you as a tosser.

16:30:23 <AlexHall> sandro: can add a simple triple into the dataset, "the time right now is X"

Sandro Hawke: can add a simple triple into the dataset, "the time right now is X"

16:31:00 <AlexHall> ... use this triple to add extra checks to see that merged graphs were at the same time

... use this triple to add extra checks to see that merged graphs were at the same time

16:31:33 <AlexHall> patH: the point is, lots of applications aren't currently doing this check and would be broken

Patrick Hayes: the point is, lots of applications aren't currently doing this check and would be broken

16:31:36 <sandro> pat: context logics, sub-intervals

Patrick Hayes: context logics, sub-intervals [ Scribe Assist by Sandro Hawke ]

16:31:48 <gavinc> +q to ask Who is asking us to fix this?

Gavin Carothers: +q to ask Who is asking us to fix this?

16:32:01 <AlexHall> david: these rules would be very complicated. i might choose to believe data that's an hour old and not a week old.

David Wood: these rules would be very complicated. i might choose to believe data that's an hour old and not a week old.

16:32:04 <ericP> q+ to give a use case: should i prescribe drug X for disease Y given old evidence that it helped and newer (but less-reviewed) evidence that it hurts

Eric Prud'hommeaux: q+ to give a use case: should i prescribe drug X for disease Y given old evidence that it helped and newer (but less-reviewed) evidence that it hurts

16:32:22 <davidwood> ack gavinc

David Wood: ack gavinc

16:32:23 <Zakim> gavinc, you wanted to ask Who is asking us to fix this?

Zakim IRC Bot: gavinc, you wanted to ask Who is asking us to fix this?

16:32:27 <AlexHall> patH: context logics have tried to account for this by adding time intervals, etc.

Patrick Hayes: context logics have tried to account for this by adding time intervals, etc.

16:32:32 <davidwood> ack ericp

David Wood: ack ericp

16:32:32 <Zakim> ericP, you wanted to give a use case: should i prescribe drug X for disease Y given old evidence that it helped and newer (but less-reviewed) evidence that it hurts

Zakim IRC Bot: ericP, you wanted to give a use case: should i prescribe drug X for disease Y given old evidence that it helped and newer (but less-reviewed) evidence that it hurts

16:33:16 <patH> eric, that is a different issue i think.

Patrick Hayes: eric, that is a different issue i think.

16:33:18 <AlexHall> ericP: the way we usually solve this is with SPARQL -- put thresholds in the query, get all information to make a human decision

Eric Prud'hommeaux: the way we usually solve this is with SPARQL -- put thresholds in the query, get all information to make a human decision

16:33:35 <Souri> Is it too naive to consider use of the fourth component (graph?) to define the context (time, space, ...): <ctxt1> { :John a :TeenAger } <ctxt2> { :John a :Octogenarian} <ctxt3>{ <ctxt1> :when 1937 . <ctxt2> :when 2007} <ctxt4> {<ctxt3> :creationYear 2012}

Souripriya Das: Is it too naive to consider use of the fourth component (graph?) to define the context (time, space, ...): <ctxt1> { :John a :TeenAger } <ctxt2> { :John a :Octogenarian} <ctxt3>{ <ctxt1> :when 1937 . <ctxt2> :when 2007} <ctxt4> {<ctxt3> :creationYear 2012}

16:34:19 <AlexHall> ... state of the art for this is to put relevant information in front of a human to make final decision

... state of the art for this is to put relevant information in front of a human to make final decision

16:34:19 <patH> souri, i think that is the only feasible ideas to standardize, but might be too restrictive.

Patrick Hayes: souri, i think that is the only feasible ideas to standardize, but might be too restrictive.

16:34:39 <AlexHall> does this scale at all?

does this scale at all?

16:34:39 <patH> +q

Patrick Hayes: +q

16:35:40 <AlexHall> gavin: out of all of us, who is trying to work on a system that is approaching this from a time-implicit way?

Gavin Carothers: out of all of us, who is trying to work on a system that is approaching this from a time-implicit way?

16:36:15 <AlexHall> sandro: asked govt people about this, they use dc:temporal with a time range, required to be in any dataset

Sandro Hawke: asked govt people about this, they use dc:temporal with a time range, required to be in any dataset

16:36:16 <davidwood> ack patH

David Wood: ack patH

16:36:20 <zwu2> I know a use case that requires associate creation timestamp with every triple

Zhe Wu: I know a use case that requires associate creation timestamp with every triple

16:37:00 <gavinc> Zakim, mute me

Gavin Carothers: Zakim, mute me

16:37:00 <Zakim> gavinc should now be muted

Zakim IRC Bot: gavinc should now be muted

16:37:02 <AlexHall> patH: saw another use case where they had an OWL ontology, described for each property its likely time persistence (short/long/medium-lived)

Patrick Hayes: saw another use case where they had an OWL ontology, described for each property its likely time persistence (short/long/medium-lived)

16:37:25 <AlexHall> ... allows for pretty complicated modeling (about weather in this case)

... allows for pretty complicated modeling (about weather in this case)

16:38:14 <AlexHall> ... going back to eric's use case, you really do have to have a human for this, it's too complex. lots of use cases are simpler, e.g. weather forecasts

... going back to eric's use case, you really do have to have a human for this, it's too complex. lots of use cases are simpler, e.g. weather forecasts

16:38:43 <AlexHall> ... think we can at least give advice to implementers about how to handle these simpler use cases

... think we can at least give advice to implementers about how to handle these simpler use cases

16:38:45 <Zakim> -Arnaud

Zakim IRC Bot: -Arnaud

16:39:17 <AndyS> zakim, who is on the phone?

Andy Seaborne: zakim, who is on the phone?

16:39:17 <Zakim> On the phone I see Peter_Patel-Schneider, davidwood, AZ, MacTed, AndyS, AlexHall, gavinc (muted), Ivan, sandro, swh, Souri, LeeF, PatH, zwu2 (muted), EricP, NickH (muted)

Zakim IRC Bot: On the phone I see Peter_Patel-Schneider, davidwood, AZ, MacTed, AndyS, AlexHall, gavinc (muted), Ivan, sandro, swh, Souri, LeeF, PatH, zwu2 (muted), EricP, NickH (muted)

16:39:20 <AlexHall> david: think implementers would say it's too much cost for not much benefit

David Wood: think implementers would say it's too much cost for not much benefit

16:39:43 <AlexHall> sandro: would love to have steve's input, they harvest lots of time-sensitive data

Sandro Hawke: would love to have steve's input, they harvest lots of time-sensitive data

16:40:00 <LeeF> swh, are you here?

Lee Feigenbaum: swh, are you here?

16:40:05 <LeeF> SteveH, are you here?

Lee Feigenbaum: SteveH, are you here?

16:40:08 <AlexHall> eric: think they incorporate a timestamp into the graph tag

Eric Prud'hommeaux: think they incorporate a timestamp into the graph tag

16:40:33 <AlexHall> ... use metadata to track the graphs

... use metadata to track the graphs

16:40:58 <swh> LeeF, yeah, Im here, was AFK breifly

Steve Harris: LeeF, yeah, Im here, was AFK breifly

16:40:59 <AlexHall> pat: this is the 4th approach so far this call. lots of different possibilities

Patrick Hayes: this is the 4th approach so far this call. lots of different possibilities

16:42:41 <AlexHall> steveH: we do incorporate a timestamp into the graph IRI, add a statement inside the graph to record this timestamp

Steve Harris: we do incorporate a timestamp into the graph IRI, add a statement inside the graph to record this timestamp

16:43:23 <AlexHall> ... if something is true across time, then it will appear in multiple graphs for as long as it's true

... if something is true across time, then it will appear in multiple graphs for as long as it's true

16:43:41 <AlexHall> eric: is the triple predictable? could it already be in the graph?

Eric Prud'hommeaux: is the triple predictable? could it already be in the graph?

16:43:54 <gavinc> Ding ding! Graph IRI varies with date, same way that WARC solved this as well.

Gavin Carothers: Ding ding! Graph IRI varies with date, same way that WARC solved this as well.

16:44:09 <MacTed> self-description is important...

Ted Thibodeau: self-description is important...

16:44:13 <AlexHall> steve: we don't allow this, we would filter out that predicate

Steve Harris: we don't allow this, we would filter out that predicate

16:44:17 <MacTed> "follow your nose" falls down without it

Ted Thibodeau: "follow your nose" falls down without it

16:44:36 <AlexHall> patH: how do you distinguish things that are time-dependent vs. what isn't?

Patrick Hayes: how do you distinguish things that are time-dependent vs. what isn't?

16:45:06 <AlexHall> steve: we don't mix different approaches in one system. either a system is time-dependent or it isn't

Steve Harris: we don't mix different approaches in one system. either a system is time-dependent or it isn't

16:45:15 <davidwood> q?

David Wood: q?

16:45:41 <AlexHall> david: eric mentioned grabbing data from a particular time range and present to the user for a choice. do you do this?

David Wood: eric mentioned grabbing data from a particular time range and present to the user for a choice. do you do this?

16:45:44 <MacTed> "the graph IRI", "inside the graph" refer to Gsnap? Gtext? Gbox?  hurrah for overloaded terms!

Ted Thibodeau: "the graph IRI", "inside the graph" refer to Gsnap? Gtext? Gbox? hurrah for overloaded terms!

16:46:00 <AlexHall> steve: we just grab the most recent value, maybe show the most recent time it was true.

Steve Harris: we just grab the most recent value, maybe show the most recent time it was true.

16:46:05 <gavinc> well, time

Gavin Carothers: well, time

16:46:54 <AlexHall> david: would like to talk about gavin's point that time is encoded in the data with graph IRIs.

David Wood: would like to talk about gavin's point that time is encoded in the data with graph IRIs.

16:47:02 <Zakim> +Arnaud

Zakim IRC Bot: +Arnaud

16:47:14 <AlexHall> sandro: would UUID's also work? you don't actually get time from the timestamp?

Sandro Hawke: would UUID's also work? you don't actually get time from the timestamped IRI?

16:47:50 <AlexHall> s/from the timestamp/from the timestamped IRI/
16:48:14 <AlexHall> steve: we mostly use the timestamp for human readability, UUID would be OK

Steve Harris: we mostly use the timestamp for human readability, UUID would be OK

16:49:05 <Souri> time-delimited truth

Souripriya Das: time-delimited truth

16:49:16 <AlexHall> david: think this discussion has been valuable. we know that people are encoding time data in RDF for stuff that's true for a time. we know people are using this in the field. we know not every fact expressed in RDF is eternally true

David Wood: think this discussion has been valuable. we know that people are encoding time data in RDF for stuff that's true for a time. we know people are using this in the field. we know not every fact expressed in RDF is eternally true

16:49:43 <patH> the real issue is, is the time-stamp part of the rdf data or not?

Patrick Hayes: the real issue is, is the time-stamp part of the rdf data or not?

16:49:53 <AlexHall> ... where does that leave us in relation to e.g. time-varying IRIs?

... where does that leave us in relation to e.g. time-varying IRIs?

16:50:39 <AlexHall> sandro: sounds like steve's approach is what i labeled as TRIG/equality, think that's a reasonable straw-man starting point

Sandro Hawke: sounds like steve's approach is what i labeled as TRIG/equality, think that's a reasonable straw-man starting point

16:50:47 <patH> and is it in each triple or just in an entire graph?

Patrick Hayes: and is it in each triple or just in an entire graph?

16:50:51 <ericP> q+ to point out that we can let people migrate from eternal to snapped

Eric Prud'hommeaux: q+ to point out that we can let people migrate from eternal to snapped

16:50:55 <gavinc> Not really no ;)

Gavin Carothers: Not really no ;)

16:51:09 <patH> :-)

Patrick Hayes: :-)

16:51:34 <AlexHall> ... vs TRIG/REST which would put the time-varying nature of the retrieval more into the core

... vs TRIG/REST which would put the time-varying nature of the retrieval more into the core

16:51:38 <patH> q+

Patrick Hayes: q+

16:52:17 <AlexHall> ... TRIG/equality makes the relation between a graph IRI and its triples time-invarying, think this is a safer approach

... TRIG/equality makes the relation between a graph IRI and its triples time-invarying, think this is a safer approach

16:52:46 <AlexHall> ... steve, after you read in a graph and associate an IRI with it, do you ever modify it?

... steve, after you read in a graph and associate an IRI with it, do you ever modify it?

16:53:01 <gavinc> "Assign an IRI that is globally unique for its period of intended use."

Gavin Carothers: "Assign an IRI that is globally unique for its period of intended use."

16:53:09 <AlexHall> steve: no, it stays constant

Steve Harris: no, it stays constant

16:53:34 <sandro> q?

Sandro Hawke: q?

16:54:07 <AlexHall> ted: that's the danger of putting timestamps into IRIs, blurs the line between opaque IRIs and the urge for humans to ascribe meaning to the IRIs

Ted Thibodeau: that's the danger of putting timestamps into IRIs, blurs the line between opaque IRIs and the urge for humans to ascribe meaning to the IRIs

16:54:15 <davidwood> ack ericP

David Wood: ack ericP

16:54:15 <Zakim> ericP, you wanted to point out that we can let people migrate from eternal to snapped

Zakim IRC Bot: ericP, you wanted to point out that we can let people migrate from eternal to snapped

16:54:44 <AlexHall> (universal agreement that you shouldn't be parsing a timestamp from an IRI, it should be explicit in triples)

(universal agreement that you shouldn't be parsing a timestamp from an IRI, it should be explicit in triples)

16:55:23 <AlexHall> eric: could get pushback from people who just want to do simple time-invariant modeling if we make it more complicated to account for time variance.

Eric Prud'hommeaux: could get pushback from people who just want to do simple time-invariant modeling if we make it more complicated to account for time variance.

16:56:17 <AlexHall> ... we should make it easy for people to start with the easy case (invariant) and optionally adding in time variance

... we should make it easy for people to start with the easy case (invariant) and optionally adding in time variance

16:57:35 <AlexHall> david: this tells me that all graphs are potentially time-variant

David Wood: this tells me that all graphs are potentially time-variant

16:57:45 <davidwood> ack PatH

David Wood: ack PatH

16:58:20 <AndyS> The graph (value) does not vary in RDF's ideal view of the world..  The value in the g-box changes.

Andy Seaborne: The graph (value) does not vary in RDF's ideal view of the world.. The value in the g-box changes.

16:58:25 <AlexHall> patH: no -- if we're talking about geologic time spans, we don't expect to RDF data to survive this

Patrick Hayes: no -- if we're talking about geologic time spans, we don't expect to RDF data to survive this

16:58:35 <MacTed> q+

Ted Thibodeau: q+

16:58:57 <sandro> Yeah.  How the heck are people supposed to publish the weather in RDF?    It's the first example in AWWW.

Sandro Hawke: Yeah. How the heck are people supposed to publish the weather in RDF? It's the first example in AWWW.

16:59:27 <AlexHall> ... if the publisher of the data expects the data to be time-varying, that has to be accounted for

... if the publisher of the data expects the data to be time-varying, that has to be accounted for

16:59:42 <sandro> ted: Until the moment things change, you may think what you're saying is going to be true for all time.

Ted Thibodeau: Until the moment things change, you may think what you're saying is going to be true for all time. [ Scribe Assist by Sandro Hawke ]

17:00:14 <AlexHall> ... macted: time variance can't necessarily be predicted, unexpected change happens all the time in science, e.g.

... macted: time variance can't necessarily be predicted, unexpected change happens all the time in science, e.g.

17:00:21 <sandro> pat: All data is subject to being wrong, yes.    But that's not the same as tomorrow's weather is going to be different from today's.

Patrick Hayes: All data is subject to being wrong, yes. But that's not the same as tomorrow's weather is going to be different from today's. [ Scribe Assist by Sandro Hawke ]

17:00:35 <swh> database people have been dealing with this for decades - it's fine

Steve Harris: database people have been dealing with this for decades - it's fine

17:00:49 <pfps> I agree with swh - strongly - there is nothing new here

Peter Patel-Schneider: I agree with swh - strongly - there is nothing new here

17:00:55 <sandro> q+

Sandro Hawke: q+

17:01:02 <Zakim> -Souri

Zakim IRC Bot: -Souri

17:01:04 <ivan> ack MacTed

Ivan Herman: ack MacTed

17:01:59 <AlexHall> macted: if data that was thought to be immutable suddenly becomes mutable, that is a bigger problem than data that was thought to be mutable actually being immutable

Ted Thibodeau: if data that was thought to be immutable suddenly becomes mutable, that is a bigger problem than data that was thought to be mutable actually being immutable

17:02:05 <sandro> q+ to say there seems to be confusion about what's mutable.    (1) what's true changes, (2) the state of resources MIGHT change or be frozen, (3) g-snaps never change.

Sandro Hawke: q+ to say there seems to be confusion about what's mutable. (1) what's true changes, (2) the state of resources MIGHT change or be frozen, (3) g-snaps never change.

17:02:49 <AlexHall> patH: that's true, but we shouldn't force all data to be mutable in the data model

Patrick Hayes: that's true, but we shouldn't force all data to be mutable in the data model

17:02:56 <davidwood> ack sandro

David Wood: ack sandro

17:03:17 <Zakim> sandro, you wanted to say there seems to be confusion about what's mutable.    (1) what's true changes, (2) the state of resources MIGHT change or be frozen, (3) g-snaps never

Zakim IRC Bot: sandro, you wanted to say there seems to be confusion about what's mutable. (1) what's true changes, (2) the state of resources MIGHT change or be frozen, (3) g-snaps never

17:03:20 <Zakim> ... change.

Zakim IRC Bot: ... change.

17:03:34 <swh> publishing weather, dc:date… next?

Steve Harris: publishing weather, dc:date… next?

17:03:38 <swh> q+

Steve Harris: q+

17:04:11 <davidwood> ack swh

David Wood: ack swh

17:04:30 <AlexHall> sandro: think we should focus on how do you publish the weather in RDF. it's the prototypical example, have no idea right now of how to do that, if we can do that then maybe it can be extended to other problems.

Sandro Hawke: think we should focus on how do you publish the weather in RDF. it's the prototypical example, have no idea right now of how to do that, if we can do that then maybe it can be extended to other problems.

17:04:34 <patH> q+

Patrick Hayes: q+

17:04:57 <davidwood> ack patH

David Wood: ack patH

17:05:03 <NickH> +1 to swh

Nicholas Humfrey: +1 to swh

17:05:16 <AlexHall> steveH: i think we're overthinking this. database people have been handling this problem just fine for decades, using timestamp fields in tables

Steve Harris: i think we're overthinking this. database people have been handling this problem just fine for decades, using timestamp fields in tables

17:05:34 <sandro> swh, any idea why data.gov.uk chose to use dc:temporal instead of dc:date ?

Sandro Hawke: swh, any idea why data.gov.uk chose to use dc:temporal instead of dc:date ?

17:05:51 <AlexHall> patH: i agree, don't think it's hard, it's a question of how to do it?

Patrick Hayes: i agree, don't think it's hard, it's a question of how to do it?

17:06:28 <swh> sandro, no idea, dc:date is possibly not the right choice, was just a strawman

Steve Harris: sandro, no idea, dc:date is possibly not the right choice, was just a strawman

17:06:31 <davidwood> "every triple is sacred"

David Wood: "every triple is sacred"

17:06:43 <AlexHall> ... don't want to have to timestamp every triple that can possibly be time-varying

... don't want to have to timestamp every triple that can possibly be time-varying

17:07:04 <AndyS> different domain of discourse

Andy Seaborne: different domain of discourse

17:07:32 <AlexHall> ... could modify the semantics if we decided a standard way of timestamping a graph. then people could understand one another.

... could modify the semantics if we decided a standard way of timestamping a graph. then people could understand one another.

17:08:13 <AlexHall> ivan: essentially defining a timestamp vocabulary

Ivan Herman: essentially defining a timestamp vocabulary

17:08:33 <AlexHall> patH: yes, and a convention for adding a timestamp triple to a graph

Patrick Hayes: yes, and a convention for adding a timestamp triple to a graph

17:09:21 <davidwood> q?

David Wood: q?

17:09:34 <sandro> ted: lack of this triple has to be taken as there-with-a-bnode --- all the RDF data out there is implicitely time dependent.

Ted Thibodeau: lack of this triple has to be taken as there-with-a-bnode --- all the RDF data out there is implicitely time dependent. [ Scribe Assist by Sandro Hawke ]

17:09:45 <AlexHall> ???: what to do with all the existing data out there?

Ted Thibodeau: what to do with all the existing data out there?

17:10:00 <AlexHall> ... it won't have this triple, but might be time dependent

... it won't have this triple, but might be time dependent

17:10:00 <sandro> s/???/ted/
17:10:26 <AlexHall> patH: think we can work out the details of this over email

Patrick Hayes: think we can work out the details of this over email

17:11:15 <AlexHall> david: if we were to do this and modify the semantics in a way with minimal impact to deployed data, would this buy us anything in the named graph discussion?

David Wood: if we were to do this and modify the semantics in a way with minimal impact to deployed data, would this buy us anything in the named graph discussion?

17:11:24 <AlexHall> patH: i think it would, yes

Patrick Hayes: i think it would, yes

17:11:49 <AlexHall> davidwood: can you formulate a proposal for a strawpoll?

David Wood: can you formulate a proposal for a strawpoll?

17:12:08 <AlexHall> patH: yes, maybe in the next week or so

Patrick Hayes: yes, maybe in the next week or so

17:12:31 <davidwood> Alex, please assign an action to Pat

David Wood: Alex, please assign an action to Pat

17:12:42 <AlexHall> ivan: not sure what you mean by this. are all triples quads where the fourth entry is a timestamp?

Ivan Herman: not sure what you mean by this. are all triples quads where the fourth entry is a timestamp?

17:13:53 <AlexHall> ... what does it mean that the timestamp vocabulary has a semantics? does it extend the model theory semantics? or is it just described in plain english?

... what does it mean that the timestamp vocabulary has a semantics? does it extend the model theory semantics? or is it just described in plain english?

17:13:54 <sandro> ivan: We have the word semantics used in the semantic web with many different semantics.  :-)

Ivan Herman: We have the word semantics used in the semantic web with many different semantics. :-) [ Scribe Assist by Sandro Hawke ]

17:14:14 <AlexHall> pat: model theory

Patrick Hayes: model theory

17:14:46 <AlexHall> ivan: this worries me. afraid that adding this to the model theory would make it too complicated.

Ivan Herman: this worries me. afraid that adding this to the model theory would make it too complicated.

17:15:03 <AlexHall> pat: don't think that describing it in english makes it any easier

Patrick Hayes: don't think that describing it in english makes it any easier

17:16:49 <AlexHall> action: patH to propose a vocabulary and semantics for adding timestamps to RDF graphs

ACTION: patH to propose a vocabulary and semantics for adding timestamps to RDF graphs

17:16:49 <trackbot> Created ACTION-141 - Propose a vocabulary and semantics for adding timestamps to RDF graphs [on Patrick Hayes - due 2012-02-08].

Trackbot IRC Bot: Created ACTION-141 - Propose a vocabulary and semantics for adding timestamps to RDF graphs [on Patrick Hayes - due 2012-02-08].

17:17:53 <Zakim> -gavinc

Zakim IRC Bot: -gavinc

17:18:04 <AlexHall> davidwood: out of time. i think if pat can make a proposal, and if it has minimal impact on existing data, then i think we have a good way forward

David Wood: out of time. i think if pat can make a proposal, and if it has minimal impact on existing data, then i think we have a good way forward

17:18:13 <sandro> we don't have a named graphs deadlock -- we have no cogent proposals on which to deadlock.

Sandro Hawke: we don't have a named graphs deadlock -- we have no cogent proposals on which to deadlock.

17:18:19 <AlexHall> ... adjourned.

... adjourned.



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This revision (#1) generated 2012-02-01 18:10:34 UTC by 'alexhall', comments: None