My presentation about a scalable architecture for a social Web of Things (Paraimpu) @ WoT2011 Workshop in San Francisco, June 12, 2011

1. The anatomy of a large scale Social
Web for Internet enabled Object
Antonio Pintus Davide Carboni Andrea Piras
CRS4
WoT 2011 - June 2011 - San Francisco, CA, USA
Antonio Pintus - pintux@crs4.it Davide Carboni - dcarboni@crs4.it Andrea Piras - piras@crs4.it 1

2. Who, where...
• Antonio Pintus and Davide Carboni and Andrea Piras
• ICT - LBS Group @ CRS4, an interdisciplinary applied research center based
in Pula (Cagliari), SARDINIA, Italy
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

3. The Web of Things
• In the Web of Things (WoT) vision, things are connected to a pervasive
wireless/wired network and can communicate with other objects and
services using HTTP-based protocols
• Everyday surrounding objects (phones, domestic appliances,
advertisement billboards, musical instruments,... ) become nodes of the
WoT
• Web-enabled objects are available on the market just now!
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

4. part #1
Our Vision
Ph. http://www.flickr.com/photos/salendron/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

5. Vision: a Social Web of Things /1
#1: connecting Things to the Web must be
simple
- simple to “plug”
- simple to con gure
- simple to manage
- Web-based UX
Ph. Nigel Marshall, http://www.flickr.com/photos/nige_mar/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

6. Vision: a Social Web of Things /2
• #2: not only “physical” Things but also “virtual”
ones
–social networks, Web sites, feeds, APIs, ...
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

7. Vision: a Social Web of Things /3
#3: interconnecting Things in the Web
must be simple
- including “physical” and “virtual”
Things
- data adapting / transformation
Ph. John Thurm, http://www.flickr.com/photos/thurm
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

8. Vision: a Social Web of Things /4
#4: Social /1: existing social networks become
connectable Things
- Authentication facilities, friends/contacts import
Ph. Nigel Marshall, http://www.flickr.com/photos/nige_mar/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

9. Vision: a Social Web of Things /5
Ph. Ryan Roberts http://www.flickr.com/photos/ryanr
#5: Social /2: Share your Things with friends!
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

10. Things Sharing
– Things sharing:
• it should be possible to share a Thing with friends and let
them use it in their connections (according to a de ned
policy: public, open, moderated)
• sharing objects goes toward a “collaborative consumption”
as shaped by the authors of the book What’s mine is yours*
* What's Mine Is Yours: The Rise of Collaborative Consumption, Rachel Botsman and Roo Rogers . Harperbusiness,
http://www.collaborativeconsumption.com/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

11. The Model: 4 basic abstractions
- Services:
- Sensors
- Actuators
- Connections
Ph. Windell Oskay http://www.flickr.com/photos/oskay/265899865/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

12. Services: Sensors
- every Thing capable to produce
data
- using HTTP
- anemometers, Arduino boards,
but also Foursquare, Pachube,
other services in the Web...
Ph. Windell Oskay http://www.flickr.com/photos/oskay/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

13. Services: Actuators
- every Thing capable to receive/
consume data and to perfom an
action
- using HTTP
- lighting systems, Arduino,
Chumby, Karotz, but also Twitter,
Facebook, other applications...
Ph. Dieter Drescher http://www.flickr.com/photos/cosmosfan
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

14. Connections
- between two Services:
- a Sensor as the source
- an Actuator as the destination
- they are con gurable:
- data ltering
- data mapping
Ph. supermaryan http://www.flickr.com/photos/33975256@N06/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

15. problems: architecture & scalability
• Scalability
– What happens when the number of users grows?
– What happens when thousands of things are added?
– What happens when thousands of near real-time data
have to be managed?
– System MUST be scalable by design!
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

16. problems: architecture & scalability
Web-based Architecture
WS-* or REST
Web server
Load balancing
Horizontal Scalability
C10K problem
Database
?
New Sensors/Actuators
Ph. MrFaber, http://www.flickr.com/photos/mrfaber
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

17. part #2
Architectural &
Design Choices
Ph. Jaime Silva, http://www.flickr.com/photos/20792787@N00/
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

18. WS-* or REST?
• in many cases adopting a WS-* stack is too complex:
WSDL, SOAP over HTTP, ...
• often, we’re talking about (limited) physical digital Things
• we’ve chosen REST as architectural style:
» Things, connections, data, users, ..., are REST
resources
» simpler, exible, “mashable”, APIs
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

19. Data persistence: SQL or NoSQL?
• Considering:
– high data heterogeneity: DB schema exibility required
– database scalability across distributed systems
– data partitioning & data replication
• We’ve chosen a NoSQL DB:
» no xed schemas, no tables, no relations
» high concurrent read-write, scalability, auto-
sharding
» JSON native format
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

20. Web server, Web front-end
• Full Web-based system
• C10K problem: 10,000 simultaneous open standing HTTP
connections (clients)
• Horizontal scalability: add new server instances when
required
• Load balancing/reverse proxy
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

21. Things Connections
• data transfers between DB-based queues
• data adaptation performed by system processes
• data adaptation rules de ned by users for each owned
connection
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

22. Data adaptation: lters
• a Filter is a boolean expression evaluated
against data coming from a Sensor
–using Javascript as expression language
» sensor > 12
» sensor. eld == ‘mylabel’
» sensor.data >20 && sensor.type == ‘temp’
» ...
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

23. Data adaptation: mappings
• Mappings are couple of expressions: (cond, repl)
• cond : a boolean expression evaluated against
Sensor data (same as for lters)
• repl : an expression producing a data value to be
forwarded to the Actuator when cond is true
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

24. Mappings, examples
– Javascript as expression language
Sensor data CONDITION REPLACE Actuator data
type type
numeric sensor > 30 <% sensor * 3.14 / 100 %> numeric
Summer is coming, temperature is:
numeric sensor > 25 text
<% sensor %> °C
Data is <% sensor.data %>
JSON sensor.data > 30 text
and type is <% sensor.type %>
<?xml version="1.0" encoding="UTF-8"?>
sensor.A0 > 30 && <value>
JSON XML
sensor.A5 <= 10 <% sensor.A0 * 100 %>
</value>
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

25. Paraimpu
• is a Web-based social tool
• allows people to:
– connect, use, share and compose Things, services and
devices to create personalized WoT applications
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

26. General Architecture
Load balancing
Web front-end
scalability
System processes (back-
end) scalability
DB scalability
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

27. Paraimpu: the workspace
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

28. Current version
• ~ 50 active alpha users
• Palette:
• 5 ready-to-use Sensors + 1 generic Sensor
• 7 ready-to-use Actuators + 1 generic Actuator
• Sharing policy: (private), public, open, moderated
• Noti cation system between users for Things sharing
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

29. Technologies
• Architecture mainly written in Python
• Web stack based on Tornado Web server
• NoSQL DBMS (MongoDB)
• HTML+jQuery
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

30. Conclusion
• We believe that a social Web of Things can help in its diffusion...
• Results are encouraging: alpha users are helping us in testing
and improving the system
• More and better test beds are under de nition to prove system
scalability in each of its critical aspects
• We’re working hard to add new features and new ready-to-use,
easy-con guration, components and Things
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

31. The prototype
http://paraimpu.crs4.it
twitter: @paraimpu
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

32. Contacts
• Antonio Pintus, pintux@crs4.it, twitter: @apintux
• Davide Carboni, dcarboni@crs4.it
• Andrea Piras, piras@crs4.it
• LBS group @ CRS4: http://geoweb.crs4.it/
• CRS4 Home Page: http://www.crs4.it
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

33. Q&A
Thank you for your attention
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Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA