Telecon 30.01.2015

Participants

• Alessandra Mileo (AM)
• Danh le Phuoc (DLP)
• Daniele Dell'Aglio
• Emanuele Della Valle (EDV)
• Jean-Paul Calbimonte
• Josiane
• Kia Teymourian
• Rene Kaiser (RK)
• Roland Stuhmer (RS)

Minutes taken by

• Daniele Dell'Aglio

Agenda

• Open Actions from last time
  • ACTION (Emanuele): Emanuele to propose graph count based window definition
  • ACTION (Roland): Roland to make an improved proposal for avoiding the AGGREGATE clause. (see [1])
  • ACTION (Daniele): to update the query according to our agreements
  • ACTION (Emanuele): to ask editors of SIGMOD records, if they are willing to publish this, or publish it in the second volume of ESWC proceedings (jp could ask), or publish as a column in a semantic web related journal

Minutes

• Graph count based definition
  • EDV: shortcut for tumbling (when slide = width)
  • JP: It should be intuitive
  • EDV: e.g., FROM NAMED WINDOW :graphBasedWindow ON s:1 [RANGE P10G TUMBLING]
  • DLP: it should be intuitive, ppl should understand what is G
  • EDV: alternative: [GRAPH RANGE 10 STEP P1]
  • DLP: what do you mean by step in the Graph-based window?
  • EDV: It is not related to execution, but a declaration of how window is built and should work
  • DLP: we should not just focus on the graph syntax
  • EDV: if we use the GRAPH keyword, then we require to also have [TIME RANGE PT10H STEP PT1H]
  • DLP: we should define the semantic of the execution
  • EDV: we are discussing the declaration, not the execution semantic
  • DLP/EDV: different executions for different use-cases

• Aggregates
  • RS: not happy of AGGREGATE, because it's not standard
  • RS: didn't find a solution, but we can use a sort of BIND
  • EDV: we decided to do not have them for now (there are verbose ways to write it), and let's think about that in a second moment, it is just a syntactic sugar
  • general agreement on that
  • EDV: discussion about aggregates with SPARQL 1.1 WG: http://www.larkc.eu/wp-content/uploads/2008/01/LarKC-D9.7-Report-of-contributions-to-standardisation-activities.pdf (chapter 3)
  • ACTION(RS): make an example starting from the discussion

• Example queries in the new language
  • JP: some of the features we are trying to include are not present in the LSBench queries
  • DLP: agree, most of the queries use time-based sliding window, with some triple-based one
  • DLP: use the DEBS Challenge scenario, where there is data and we can work on that: http://www.debs2015.org/call-grand-challenge.html
  • DLP: data about NY taxis, geographical info, and trace of the trips. Example queries: discover the most profitable data. We could combine it with Linked Geo Data
  • EDV: we should check if the data is not too much relational
  • DLP: we could work to convert it in RDF
  • EDV: let's try; alternative plan: we have an example written in a book chapter that mix different streams, can it be used?
  • EDV: we can convert them in the new language queries
  • ACTION(DLP): to start a page on GitHub to begin the discussion about the schema
  • ACTION(EDV): to invite Danh in the GitHub RSP group

• RSP Workshop @ ESWC
  • JP: who will be there?
  • AM, EDV, JP: I'll be there
  • DLP: maybe
  • EDV: Still working on the possibility to publish the report
  • RK: If one would attend just that one day, would you have to pay the whole conference fee?
  • EDV: Maybe, to be checked
  • RK: Ok thanks, I'll monitor the website for news
  • EDV: To be checked if it is possible to have a long report on the post-proceedings volume
  • AM, JP will check
  • EDV: split the ppl in groups and write contributions for the final report
  • AM: We should investigate how they plan to do the volume

• Next phone call
  • Feb 13, 15.00 CET

Actions

• ACTION(RS): make an example starting from the discussion
• ACTION(DLP): to start a page on GitHub to begin the discussion about the schema
• ACTION(EDV): to invite Danh in the GitHub RSP group

Agreements

summarize agreements here, if any were made