Presentation at OrdRing 2013 (2nd International Workshop on Ordering and Reasoning) at ISWC 2013, Sydney.

1. EVENT OBJECT BOUNDARIES
IN RDF STREAMS
– A Position Paper –
Robin Keskisärkkä and Eva Blomqvist
Department of Computer and Information Science
Linköping University, Sweden
{robin.keskisarkka|eva.blomqvist}@liu.se

2. PROBLEM
Streaming of event objects represented in RDF
 Each event object can typically not be described by
a single triple
 Querying of a partial event object may lead to
misleading or false results
 How can we respect event object boundaries in
RDF streams?


3. STREAM CHARACTERISTICS
Ordered vs. unordered
 Sequential vs. overlapping
 Triples vs. graphs


4. STREAM CHARACTERISTICS

Other important aspects
Complexity, size, and streaming rate of event objects
 Limitations of the stream producer/consumer
 Timestamps
 (…)


5. PROBLEM
Request: Fire truck

6. POSSIBLE APPROACHES
1)
2)
3)
4)
Header
Commonality
RDF graph streams
Customized decomposition

7. APPROACH 1: HEADER

8. APPROACH 2: COMMONALITY

9. APPROACH 3: RDF GRAPH STREAM

10. APPROACH 4: CUSTOMIZED DECOMPOSITION

11. DISCUSSION
Requires more attention
 Homogeneous streams are relatively simple
 Many real-world streams are heterogeneous
 Outline of different approaches
 Standards and vocabularies


12. QUESTIONS?
Pros and cons of streaming graphs?
 Which to support right now?
 What about timestamps?
 What are the limitations of stream producers?
 Boundaries in streams?
