Towards a Web of Sensors built with Linked Data and REST S. Turchi, L. Bianchi, F. Paganelli, F. Pirri, D. Giuli, “Towards a web of sensors built with linked data and REST”, 2013 IEEE 14th International Symposium on a World of Wireless, Mobile and Multimedia Networks, WoWMoM 2013, art. no. 6583491, Madrid, Spain, 4-7 June 2013, 10.1109/WoWMoM.2013.6583491
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References
• S. Turchi, L. Bianchi, F. Paganelli, F. Pirri, D. Giuli, “Towards a Web of Sensors built with Linked Data and REST”, 2nd IEEE WoWMoM Workshop on the Internet of Things: Smart Objects and Services (IoT-SoS 2013, colocated with 14th IEEE Int. Symp. on a World of Wireless, Mobile and Multimedia Networks (WoWMoM 2013), Madrid, Spain 4-7 June.
• F. Paganelli, S. Turchi, L. Bianchi, L. Ciofi, M.C. Pettenati, F. Pirri, and D. Giuli, "An information-centric and REST-based approach for EPC Information Services, Journal of Communications Software and Systems, vol. 9, no. 1, March 2013
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Outline
• Context and Motivation
• Our approach towards a Web of Sensors
• Information-centric model
• Web APIs
• Middleware services
• Ongoing experiment within the SmartSantander EU project
• Conclusions
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Context
• Web of Things • Ease the end-user
interaction with sensors and smart objects by leveraging the Web
• Functionalities for publishing the sensors’ representation and make them accessible on the Web
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Motivation State of the art in the Web of
Things/Web of Sensors (WoS):
• SensorWeb OGC specifications
• Several research and implementation proposals • Web APIs (REST)
• Semantic annotations and links (Linked Data)
Current limitation
• Poor support to the development of web applications in the WoS
• A limitation to access, reuse and compose sensor data
• i.e. the WoS objective!
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Our Proposal
• A graph-based representation of sensors
• Original combination of REST and Linked Data principles
• WoT as a browsable graph of resource nodes
• Uniform Web Interface
• Creation and Execution environment
• Middleware implementing discovery, search, brokering capabilities
• Design tools (GUI and JavaScript libraries)
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Why REST and Linked Data?
• Leverage the Web’s grounding principles and best practices
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What it is… Useful for…
REST
• Architectural style • Uniform Interface (HTTP verbs) • It is based on the principles that
make the web scalable
• Lowering entry barriers for web developers
• Offering lightweight and uniform API for accessing data
Linked Data
• A set of best practices for publishing and connecting data and their semantics on the Web
• Standard technologies (HTTP, RDF, XML, …)
• Global browsable information space, interlinking data coming from different information sources
• Shared representation of interlinked data
REST and Linked Data complement each other!
IDN Information Model
• Node: an information element, made by data (content) and metadata • URI-addressable
• Relations • Aggregation
• Reference
• Document: a collection of IDN Nodes (1..n) exposed as a web resource • Uniform REST interface
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attribute1
attributeN attribute2
…/{nodeId}
attribute attribute
../../{nodeid} ../ …/{nodeId}
attribute
../{nodeId}
1 1
aggregation link
../{nodeId}
reference link
Sensor Information Model Sensor object representation
• GET URI information retrieval
• PUTcreation/update
• DELETE deletion
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Different design choices are allowed!
nodeId
type battery
sensor/{nodeId}
longitude latitude
../location ../data_production
date
../{physical_quantity}
value measurement_unit
1 1
1..n
aggregation link
Exploiting the Model - 1 Virtual sensor • software-based sensor whose value derives from physical sensor ones • Advantages:
• Geographical coverage • New sensor type
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Exploiting the Model – 2 Interlinking sensor information • more complex graphs can be built
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sensor/{nodeId}
sensor/{nodeId}
sensor/{nodeId}
InterDataNet Architecture
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IDN Adapter
IDN Service Platform
Information-centric REST APIs ID
N S
ear
ch
IDN
Stu
dio
Sensing Infrastructures
Information repositories
REST and Web Services
Experiment in SmartSantander
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IDN Adapter
IDN Service Platform
Information-centric REST APIs
IDN
Se
arch
IDN
Stu
dio
Web Applications
Users
Apparent Temp. (AT) Web App • VSs for AT in locations like schools, public gardens, hospitals
• AT = + 06
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Benefits
• End users • Quality of Life
• Alerts
• Developers • Fast development
process
• Reduced programming skills
Conclusions
• Approach for easing the building of a Web of Sensors • Connection to sensors and existing sensor middleware through a
dedicated adapter
• Representation of objects through a graph of URI-addressable data units
• Thanks to the adoption of REST and Linked Data principles • Interoperability and scalability
• Tools easing the development of web of sensors applications
• Ongoing work • Experiment in SmartSantander
• Semantic-enabled search capabilities
• Security Framework
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