Telecon 04.04.2014

From RDF Stream Processing Community Group

Participants

  • Darko Anicic
  • Avi Bernstein
  • Danh Le Phuoc
  • Roland Stuehmer
  • Claudio Di Ciccio
  • Alasdair Gray
  • Jean-Paul Calbimonte
  • Oscar Corcho
  • Daniele Dell'Aglio
  • Axel Polleres


Minutes

  • JP: discussing the model, roland's proposal
  • Danh: deal with streams without timestamp
  • Roland: an option is to materialize the system tiemstamp
  • Alasdair Gray: Distinction between Roland's and the previous suggestion is that the timestamps are embedded within the graph
  • Alasdair Gray: Question is what to do about graphs without timestamps
  • Roland: events should be immutable
  • Alasdair Gray: Graphs should be immutable, but the processing timestamp would be something that is needed to be added later on
  • from Alasdair Gray: (In this discussion, a timestamp can either be a single timepoint or an interval)
  • Avi: The question is really of compactness
  • Avi: If you put the intervall in the graph then you may need a graph for each event
  • Alasdair Gray: Avi: whenever a timestamp is added to an event, it needs to be clearly captured in the RDF that it is an annotation on the original event
  • Avi: AGree
  • jp: Discussion: immutability of events, enrichment of incoming events
  • Alasdair Gray: I'm happy with the capturing of the timestamps as annotations
  • jp: Action: Roland to write the options mentioned and make them circulate
  • Daniele: annotation of original events->links to provenance
  • Daniele: what happens with events that you don't know when they end?
  • Roland: in our system, don't allow events with only start time
  • Roland: possible use case for this in a distributed system
  • Roland: long running event pattern
  • jp: Discussion: events and facts: distinction
  • Axel Polleres: hmmm, very few "facts" are entirely static, or now?
  • Axel Polleres: Where do you draw the line?
  • Avi: Look at the publication above
  • Avi: < s, p, o> [start_time, NOW() ]
  • Alasdair Gray: Something like that, essentially we are allow events that do not have an end time stated
  • Alasdair Gray: with the assumption that it will be added eventually
  • jp: I'm fine with that possibility
  • Avi: Yes!
  • Daniele (PoliMI): +1
  • Avi: Where is the agenda?
  • Alasdair Gray: The model must be defined independently of a serialisation, i.e. it should work for all RDF serialisation. We can use a serialiation for our discussion, but the model must not depend upon it
  • Daniele (PoliMI): yes, i totally agree
  • jp: i agreee
  • Daniele (PoliMI): my doubt is if after the model we should also talk about serialisations
  • Daniele (PoliMI): or if it is out of scope
  • jp: I think RDFy approaches are an advantage
  • Alasdair Gray: Agenda
  • Alasdair Gray: - The plan is to continue with the model discussion (hopefully we can come up with an agreement)

http://www.w3.org/community/rsp/wiki/RSP_Query_Semantics, - Short term planning: at this stage it might be good to evaluate where we are now. - Possibility of F2F at ESWC

  • JeanPaul: Now talking about the possibility of starting the writing up of a report (so that we can clean up the existing bits and pieces)
  • Oscar Corcho: +1
  • Alasdair Gray: +1
  • Danh: +1
  • Oscar Corcho: I like the idea. Specially because of the cleaning up so as to avoid problems like today's email discussion
  • Oscar Corcho: Avi: Proposes to agree on the document outline at ESWC
  • Roland: not there, but likes the idea of the f2f meeting
  • jp: +1 for doc outline
  • Darko: not there either. An alternative for this could be a workshop on Web of Things (when?)
  • Alasdair Gray: When and where is the Siemens event?
  • Oscar Corcho: June 25th-26th
  • Oscar Corcho: First f2f: working on the doc outline at ESWC
  • Oscar Corcho: Second f2f: people can continue, if there, at Siemen's event
  • Oscar Corcho: Who is at ESWC? Jean Paul, Oscar, Avi, Daniele, (anybody else?)
  • Oscar Corcho: \methinks That sounds like a plan
  • Alasdair Gray: I'm happy for those who can make it to ESWC to start drafting things
  • Oscar Corcho: SIEMENS event --> W3C event on Web of Things organised by Siemens
  • Oscar Corcho: ACTION (Alasdair): create a google doc or similar for everybody to help
  • Oscar Corcho: Sorry, Alasdair, I assigned it to you ;-)
  • Oscar Corcho: AGENDA ITEM: Next calls?
  • Oscar Corcho: In 2 weeks, retake discussion on model semantics
  • Oscar Corcho: assuming that there will be more invormation in the wiki
  • Oscar Corcho: +1
  • Darko Anicic (Siemens): +1
  • Oscar Corcho: There is agreement to work on that
  • Oscar Corcho: AGENDA ITEM: AOB?
  • Oscar Corcho: Easter break in DERI
  • Oscar Corcho: better to postpone one week
  • Oscar Corcho: next call 25th
  • Oscar Corcho: next call April 25th
  • Darko Anicic (Siemens): could not access the doc link
  • Oscar Corcho: next calls: April 25th, May 9th