The document discusses integrating data and services in the Web of Things from a representational state transfer (REST) perspective. It describes representing physical devices as web resources that can be accessed via HTTP requests and addressed with URIs. Properties and actions of devices are represented as addressable sub-resources that can be manipulated via RESTful operations. Semantic annotations like microformats are proposed to enable service discovery and facilitate mashing up IoT services. Several European Union-funded research projects are summarized that aim to develop open platforms and techniques for integrating smart devices and their data on the Web.

1. Service Integration – A Web of Things Perspective
W3C Workshop on Data and Services Integration [Bedford / MA, October 2011]
Simon Mayer [simon.mayer@inf.ethz.ch]
Distributed Systems Group, ETH Zurich

2. The Web of Things: Quick rundown
+ Internet Connection* + Embedded Web server
+ Resource-Oriented Modelling (REST)
* Hui, J.W., and Culler, D.E.: IP is dead, long live IP for wireless sensor networks. (2008)
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3. Representational State Transfer (REST)
Addressable, linked resources
[http://vs.inf.ethz.ch/wot/sunspots/spot1/sensors/temperature]
Defined set of operations
[PUT «true» /sunspots/spot1/actuators/leds/led1/switch]
Representations & Content Negotiation
[HTML for humans, JSON for machines,…]
Fielding, R.T.: Architectural Styles and the Design of Network-based Software Architectures
Richardson, L., and Ruby, S.: RESTful Web Services
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4. The Web of Things: REST benefits
 Great for open, interoperable APIs
 Greatly facilitates building of physical mashups [http://derekskeba.com]
 Web features for free
 It scales!
 Caching, security mechanisms
 Bookmarking your devices and their functionality
 Seems to facilitate application development
 People are used to the Web and its resources and links!
Wednesday, 20th July 2011 ICiS Physical Computing Workshop [Park City, July 2011] 4

5. The Web of Things: REST benefits
 Great for open, interoperable APIs
 Greatly facilitates building of physical mashups [http://derekskeba.com]
 Web features for free
 It scales!
 Caching, security mechanisms
 Bookmarking your devices and their functionality
 Seems to facilitate application development
 People are used to the Web and its resources and links!
Wednesday, 20th July 2011 ICiS Physical Computing Workshop [Park City, July 2011] 5

6. The Web of Things: RESTful Sun SPOTs
[http://www.sunspotworld.com]  Demo
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7. Next step in Web-based smart things
environments: Physical mashups
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8. Service Discovery: Smarter Things?
 Adding semantics for service discovery
 RDF, Microformats, Microdata
 Microdata: www.schema.org, data-vocabulary.org
...and tell others!
 Make things just smart enough to know what they can (basically) do…
 Syntactic level (e.g. data types)
 Semantic level?
 Goal: Support users in mashing up services in smart things
ecosystems!
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9. Now...
 3 Applications in need of smart things data/services
integration...
InterWoTions
 And how we solved the problem for each of them...
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10. The Friends and Things Project
 Sharing of physical and digital artifacts based on social networks
Guinard, D., Fischer, M., Trifa, V.,: Sharing Using Social Networks in a Composable Web of Things
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11. The Friends and Things Project
@home Sharing your energy consumption
Encouraging energy savings…
@work Laboratory automation
“You may monitor my mass spectrometer”
@business Sharing the trace of tagged products
RESTful EPCIS
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12. Crawling the Web of Things
 Using simple HTTP operations
 GET, HEAD, OPTIONS
 Sufficient for Friends and Things Application!
 Demo
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13. The InfraWoT Project
 Management infrastructure for smart things
 Allows to find services offered by Web-enabled resources
 Globally, but with emphasis on nearby things!
 Things have to be registered first!
 Calls for thing-embedded semantic information (name, type, services, location,…)
Trifa, V., Guinard, D., Mayer, S.: Leveraging the Web for a Distributed Location-aware Infrastructure for the Real World
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14. Composite Microformats
 Idea: Combine multiple Microformats to annotate resources
 hProduct: Product information
 hReview: Smart Thing Reviews
 Geo: Location
 hRESTS: Service descriptions
 label, data format, REST method, output
 Worked well for searching for resources
 Demo
Hong, S.: Mobile Discovery in a Web of Things. Master’s Thesis.
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15. The InterWoTions Project
InterWoTions
 Model-based user interface generation for smart things
 Requirement: User-friendlyness
 enable any developer to annotate smart things...
...without requiring prior training!
Mayer, S., Tschofen, A.: Composable Interaction Descriptions for Smart Things. Submitted.
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16. Microdata
InterWoTions
Human- and machine-readable volume controller interaction markup.
 Demo
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17. Environments of smart things...
Temperature: 24˚C Please configure
forecast data source
Human-readable and understandable
Your fridge currently
consumes 45W
Forecast: Rain
I’m located in Zurich!
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18. ...and multiple semantic annotation formats...
…<div itemscope><div ...
Temperature: 24˚C Please configure
itemprop=“tag=“>Illumination</div><div
forecast data source
itemprop=“value”>150</div></div>…
{“consumption”:”45”,
{“data”:[{“weather- “unit”:”Watts”,
forecast”:”Rain”}], Your fridge currently
“appliance”:”fridge”}
“name”:”MyNabaztag”} consumes 45W
Forecast: Rain <div class="geo">GEO: <span
class="latitude">8.549902</span>,
<span class="longitude">-
I’m located in Zurich!
47.378088</span></span></div>
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19. ...and multiple semantic annotation formats...
…<div itemscope><div ...
Content type: text/html
itemprop=“tag=“>Illumination</div><div
Annotations: Microdata
itemprop=“value”>150</div></div>…
Machine-readable
{“consumption”:”45”,
{“data”:[{“weather- Content type:
“unit”:”Watts”,
Content type: application/json
forecast”:”Rain”}], application/json
“appliance”:”fridge”}
“name”:”MyNabaztag”}
<div class="geo">GEO: <span
class="latitude">8.549902</span>,
Content type: text/html
<span class="longitude">-
Annotations: Microformats
47.378088</span></span></div>
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20. Given the representation of a (Web) resource, extract interesting
information about that resource regardless of the annotation format
used
Approach Discovery based on a runtime-dynamic set of
Strategies (e.g. Microformats-, Microdata-Strategy,...)
Mayer, S., Guinard, D.: An Extensible Discovery Service for Smart Things
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21. The DiscoWoT Project
GET /analyze?thing.wot.org
Information on thing.wot.org
 Apply every strategy to all information accessible about submitted data
 Can handle protected resources and resources behind firewalls
 Great help for decoupling service providers and consumers
 Demo
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22. Announcing WoT 2012
Third International Workshop on the Web of Things
Stay tuned: http://www.webofthings.com/wot
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23. Acknowledgements
Web of Things team @ ETH Zurich
Dominique Guinard, Vlad Trifa, Matthias Kovatsch, Benedikt Ostermaier
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