Paraimpu: a social tool for the Web of Things @ WoT2011

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

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

2
Antonio Pintus, Davide Carboni, Andrea Piras WoT2011 - June 2011- San Francisco, CA, USA

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!

3

part #1

Our Vision

Ph. http://www.flickr.com/photos/salendron/
4

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/
5


• #2: not only “physical” Things but also “virtual”
ones
–social networks, Web sites, feeds, APIs, ...

6


#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

7


#4: Social /1: existing social networks become
connectable Things

- Authentication facilities, friends/contacts import

Ph. Nigel Marshall, http://www.flickr.com/photos/nige_mar/

8

Ph. Ryan Roberts http://www.ﬂickr.com/photos/ryanr

#5: Social /2: Share your Things with friends!
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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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The Model: 4 basic abstractions

- Services:
- Sensors
- Actuators

- Connections

Ph. Windell Oskay http://www.ﬂickr.com/photos/oskay/265899865/

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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/
12

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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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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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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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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part #2

Architectural &
Design Choices

Ph. Jaime Silva, http://www.flickr.com/photos/20792787@N00/
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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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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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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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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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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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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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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>

24

Paraimpu

• is a Web-based social tool

• allows people to:

– connect, use, share and compose Things, services and
devices to create personalized WoT applications

25

General Architecture

Load balancing

Web front-end
scalability

System processes (back-
end) scalability

DB scalability

26

Paraimpu: the workspace

27

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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Technologies

• Architecture mainly written in Python

• Web stack based on Tornado Web server

• NoSQL DBMS (MongoDB)

• HTML+jQuery

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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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The prototype

http://paraimpu.crs4.it

twitter: @paraimpu

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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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Q&A

Thank you for your attention

33

Paraimpu: a social tool for the Web of Things @ WoT2011

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