The document discusses Linked Stream Data, which combines three buzzwords: Linked Data, Open Data, and Data Streams. Linked Data refers to connecting data on the web using common standards like HTTP, URIs, and RDF. Open Data involves making data freely available on the web. Data Streams refer to sequences of time-varying data elements generated in real-time from sources like sensors. The document argues that combining these concepts allows streaming and linking real-time open data on the web in a way that is processable by machines. It provides examples of domains like transportation that generate continuous open data streams and could benefit from Linked Stream Data techniques.

1. LSD
Madrid, Spain, 17/06/2014
Oscar Corcho
ocorcho@fi.upm.es, ocorcho@localidata.com
@ocorcho
http://slideshare.net/ocorcho

2. LSD
• The conversation
• Oscar: Daddy, I am going to make a presentation today on a geeks’
meeting, having a few beers, and talking about LSD…
• Oscar’s dad: What the hell did you learn at University?
• Lysergic acid diethylamide (LSD)
• A very popular substance in the 60s…
2
Don’t worry, today we are only taking beers… ;-)
And we will be talking about Linked Stream Data

3. A tale of three buzzwords:
Linked Data, Open Data and Streams 
Linked (Open) Stream Data
Madrid, Spain, 17/06/2014
Oscar Corcho
ocorcho@fi.upm.es, ocorcho@localidata.com
@ocorcho
http://slideshare.net/ocorcho
Acknowledgements: Marco Balduini, Jean Paul Calbimonte,
Daniele Dell'Aglio, Emanuele Della Valle, Juan Sequeda,
Guillermo Alvaro, Olaf Hartig and many others that I may have
omitted

4. Big Data
It’s buzzword time… And I do not wear a tie ;-)
Speaker:
Date: 26/06/2014
Data
Streams
Linked
Data
Open
Data
Linked (Open)
Stream Data
Sequeda, J. and Corcho, O.: Linked Stream Data: A Position Paper; In 2nd International
Workshop on Semantic Sensor Networks (SSN09), 2009

5. Buzzword #1: Linked Data
• Use the Web like a single global database
• Move from a Web of documents to a Web of Data
• And obviously Google (and others) have already started working on it
• Google Knowledge Graph
• schema.org
5
MovieDB
CIA
World
FactBook
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig

6. Linked Data enables such Web of Data
6
MovieDB
CIA
World
FactBook
Global Identifier: IRI (Internationalized Resource Identifier), which is a string of characters used
to identify a name or a resource on the Internet.
http://cia.../Bolivia
http://imdb.../TLLuvia
Data Model: RDF (Resource Description Framework), which is a standard model
for data interchange on the Web
http://.../population
http://.../name
8000000
“Even the Rain”
Access Mechanism: HTTP
Connection: Typed Links
http://.../filming_location
© Slide adapted from “5min Introduction to Linked Data”- Olaf Hartig, and prepared by Boris Villazón

7. Buzzword #2: Open Data and 5-star Linked Open Data
• “Open data is data that can be freely used, reused
and redistributed by anyone - subject only, at most, to
the requirement to attribute and sharealike.”
7<<Texto libre: proyecto, speaker, etc.>>[source: Open Data Handbook, http://opendatahandbook.org/en/what-is-open-data/ ]

8. Buzzword #2+: (Isolated) Open Data Portals
8<<Texto libre: proyecto, speaker, etc.>>
Sorry, 007 agent, but we like it “stirred, and not only shaken”
Some good news soon about achieving interoperabilty among them,
with the participation of a large number of cities and regions

9. Buzzword #3. Data Streams
[source http://y2socialcomputing.files.wordpress.com/2012/06/social-media-visual-last-blog-post-what-happens-in-an-internet-minute-infographic.jpg ]

10. It‘s a streaming World!
• Oil operations
• Traffic
• Financial markets
• Social networks
• Generate data streams!
10

11. It‘s a streaming World!
• In a well in progress to drown,
how long time do I have given
its historical behavior?
• Is public transportation
where the people are?
• Can we detect any intra-day
correlation clusters among
stock exchanges?
• Who is driving the discussion
about the top 10 emerging topics ?
• … want to analyse data streams
in real time and to receive
answers in push mode
11
E. Della Valle, S. Ceri, F. van Harmelen, D. Fensel It's a Streaming World! Reasoning
upon Rapidly Changing Information. IEEE Intelligent Systems 24(6): 83-89 (2009)

12. Data Streams and Continuous Semantics
• Data streams are unbounded sequences of time-
varying data elements
• Continuous queries registered over streams that, in
most of the cases, are observed trough windows
window
input streams streams of answerRegistered
Continuous
Query
12
Dynamic
System

13. Example
• Input
• Smoke and Temperature sensors in many areas
• Query
• Alert me when there is a fire, i.e. smoke and temp>50
• DSMS formulation
• Stream the areas where smoke is detected over two windows open on
smoke and temperature streams
Select IStream(Smoke.area)
From Smoke[Rows 30 Slide 10], Temp[Rows 50 Slide 5]
Where Smoke.area = Temp.area AND Temp.value > 50
• CEP formulation
• Rise a fire event in an area when smoke and high temperature events are
received within 1 minute
define Fire(area: string, measuredTemp: double)
from Smoke(area=$a) and
each Temp(area=$a and val>50) within 1min.
where area=Smoke.area and measuredTemp=Temp.value
13

14. Linked (Open) Stream Data and Stream Reasoning
• Data streams can be just another form of Linked Data
• Many relevant reasoning methods are not able to
deal with high frequency data streams
• However, trade-off exists between the complexity of
the reasoning method and the frequency of the data
stream the reasoner
14
Raw Stream Processing
Semantic Streams
Logic Programs
DL
Complexity
Reasoning
Querying
Rewriting
Abstraction
Selection
Interpretation
Change Frequency
PTIME
2NEXPTIME
104 Hz
1 Hz
Dynamics and Scale vs. Complexity
Heiner Stuckenschmidt, Stefano Ceri, Emanuele Della Valle, Frank van Harmelen:
Towards Expressive Stream Reasoning. Proceedings of the Dagstuhl Seminar on
Semantic Aspects of Sensor Networks, 2010.
AC0

15. morph-streams: Overview
16
Query
rewriting
Query Processing
Client
SPARQLStream
[tuples]
[triples/bin
dings]
Algebra
expression
R2RML
Mappings
Morph-streams procesing SPARQLStream queries
SELECT ?proximity
FROM STREAM
<http://streamreasoning.org/SensorReadings.srdf> [NOW–5
S]
WHERE {
?obs a ssn:ObservationValue;
qudt:numericalValue ?proximity;
FILTER (?proximity>10) }
SELECT prox
FROM sens.win:time(5 sec)
WHERE prox >10
π
timed,prox
ω
σ
prox>10
5 Seconds
sens
Data
translation
SNEE
Esper
GSN
Cosm
pull/push
https://github.com/oeg-upm/morph-streams
Other

16. Do you want to try it?
19<<Texto libre: proyecto, speaker, etc.>>
http://streams.linkeddata.es/

17. Map4RDF iOS and the EMT data stream
20

18. A tale of three buzzwords:
Linked Data, Open Data and Streams 
Linked (Open) Stream Data
Madrid, Spain, 17/06/2014
Oscar Corcho
ocorcho@fi.upm.es, ocorcho@localidata.com
@ocorcho
http://slideshare.net/ocorcho
Acknowledgements: Marco Balduini, Jean Paul Calbimonte,
Daniele Dell'Aglio, Emanuele Della Valle, Juan Sequeda,
Guillermo Alvaro, Olaf Hartig and many others that I may have
omitted