Interoperability in the Internet of Things is critical for emerging services and applications. In this presentation we advocate the use of IoT ‘hubs’ to aggregate things using web protocols, and suggest a staged approach to interoperability. In the context of a UK government funded project involving 8 IoT projects to address cross-domain IoT interoperability, we introduce the HyperCat IoT catalogue specification. We then describe the tools and techniques we developed to adapt an existing data portal and IoT platform to this specification, and provide an IoT hub focused on the highways industry called ‘Smart Streets’. Based on our experience developing this large scale IoT hub, we outline lessons learned which we hope will contribute to ongoing efforts to create an interoperable global IoT ecosystem.

1. IoT Interoperability:
A Hub Based Approach
Michael Blackstock, Rodger Lea
Human Communication Technologies Lab
Electrical and Computer Engineering Department
University of British Columbia
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2. Motivation
• Connection of things to the internet is not enough
• Realize potential of the IoT by providing ability to find,
access, manage and (inter)connect things
• Logical next step is to exploit the web - HTTP, JSON,
RESTful web services - a “Web of Things”
• MAGIC Broker at IoT 2010; WoTKit at IoT 2012
• Today, large scale hubs store thing data, support
search and interaction
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3. IoT Hubs
• General purpose and product-specific
hubs aggregate representation of
things and their (meta) data
• easier for app developers
• can include related data & resources
• Do not (typically) interoperate with
each other
• Standardization process necessary to
avoid islands of things
• Early standardization may stifle
innovation
• Need a balanced path toward
Interoperability
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4. Path to Hub Interoperability
Model Hub Profiles
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IoT Core
Expose things and
associated metadata
using web protocols.
Minimal interoperability
leaving app and tool
developers to do more
of the work.
Agreement on
approaches and
models
e.g. catalogs, things,
groups of things
Eases adapter
development.
Implementation
decisions on
resources,
representations,
access control and
security for hubs.
Direct adapter code
reuse is possible.
Ontologies and
semantics of things
and data. Deeper
integration is possible
and little or no
adaptation required.
from experience, refine models,
implementation and profiles

5. IoT Ecosystem Demonstrator
• UK Technology Strategy
Board Funded 8 IoT Hubs
• Stimulate development of IoT
applications and services
• All 8 in different clusters/
domains
• A key goal - interoperability
between clusters
DISTANCE
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Small IoT Interop
Highways
Airports
Smart Buildings
Transportation
Smart Campus
Vehicles
Schools and Education
IoT-Bay

6. Approach
• Web technologies at the
core, often using existing
IoT platforms
• Each consortium
implements one or more
‘hubs’
• Hubs communicate with
things to expose them to
applications
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AApppplilcicaatitoionn Application
IoT Hub
Things and data
Other
Hubs
Other
Hubs
Other
Hubs

7. TSB Project Interop API
• Provide access to “thing” data
and information about what
that data represents.
• Focus on interface between
applications and hub. Use
data from at least one other
hub.
• Lightweight, minimal
requirements for exchanging
catalogs of things - HyperCat
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AApppplilcicaatitoionn Application
IoT Hub
Things and data
Other
Hubs
Other
Hubs
Other
Hubs
1
2
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8. HyperCat
• Open catalogue format for
collections of web resources
• not just IoT resources
• JSON format where ‘things’
identified as resources
(URLs)
• RDF-like relationship/value
pairs describe what thing
resources represent or
data associated with things
• defines CRUD operations
• basic search, security
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9. Simple Catalogue
Catalogue
Description
{ "item-metadata":[
{ “rel”:”urn:X-tsbiot:rels:isContentType",
"val":"application/vnd.tsbiot.catalogue+json" },
{ “rel":"urn:X-tsbiot:rels:hasDescription:en",
"val":"Bare catalogue" }
], “items":[
!
{ "href":"http://hub.com/resource1",
“i-object-metadata”: [
{ “rel":"urn:X-tsbiot:rels:hasDescription:en",
"val":"The first resource" } ]
},
!
{ "href":"http://hub.com/resource2",
“i-object-metadata”:[
{ “rel":"urn:X-tsbiot:rels:hasDescription:en",
"val":"The second resource”}]
}
] }
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Item
Descriptions

10. HyperCat for open data
Catalogue supports “Simple Search”
Dataset Item URL
Mandatory meta data - description
and content type
{ "item-metadata" : [ { "rel" : "urn:X-tsbiot:rels:isContentType",!
"val" : "application/vnd.tsbiot.catalogue+json"!
},!
{ "rel" : "urn:X-tsbiot:rels:hasDescription:en",!
"val" : "Smart Streets data catalogue that contains static resources."!
},!
{ "rel" : "urn:X-tsbiot:rels:supportsSearch",!
"val" : "urn:X-tsbiot:search:simple"!
}!
],!
"items" : [ !
{ "href" : “/cat/data/average-temperature-and-rainfall-england-and-wales",!
"i-object-metadata" : !
[ { "rel" : "urn:X-smartstreets:rels:lastUpdate",!
"val" : "2013-06-19T00:00:20.761429"!
},!
{ "rel" : "urn:X-smartstreets:rels:hasId",!
"val" : "3f952707-b04e-4a32-a807-a53b6fa0ee58"!
},!
{ "rel" : "urn:X-smartstreets:rels:hasLicense",!
"val" : "UK Open Government Licence (OGL)"!
},!
{ "rel" : "urn:X-smartstreets:rels:hasName:en",!
"val" : "average-temperature-and-rainfall-england-and-wales"!
},!
{ "rel" : "urn:X-tsbiot:rels:hasDescription:en",!
"val" : "Average temperature and total rainfall in England and Wales : 1845 to 2010"!
},!
{ "rel" : "urn:X-smartstreets:rels:tags",!
"val" : "average-rainfall,average-temprature,england,new-tag-1,new-tag-2,wales"!
},!
{ "rel" : "urn:X-smartstreets:rels:hasVisibility",!
"val" : "public"!
},!
{ "rel" : "urn:X-tsbiot:rels:isContentType",!
"val" : "application/vnd.tsbiot.catalogue+json"!
},!
{ "rel" : "urn:X-tsbiot:rels:supportsSearch",!
"val" : "urn:X-tsbiot:search:simple"!
},!
{ "rel" : "urn:X-tsbiot:rels:containsContentType",!
"val" : "application/vnd.ms-excel"!
}!
]!
},!
{ ... additional items ... }!
]!
}
exact match on rel or value

11. Smart Streets Hub
• WoTKit IoT Platform at the
core
• Static data management:
CKAN Open Data Portal
• HyperCat API Proxy
• Landing site and Hub ‘App
Store’
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HyperCat API Proxy
CKAN Open
Data Portal
Static
Data
Files
Landing Site
Apps Apps Apps
WoTKit IoT Platform
Sensor
Gateways
Sensor
networks and
real time
updates

12. WoTKit
• Web-centric IoT Toolkit - IoT 2012
• Thing data manager and
aggregator
• 2 way: sense or control
• Visualizations
• Finding & sharing things
• Access control and search by
organizations, groups, tags, meta
data
• Real time processing and alerts
• Commercialized by Sense
Tecnic Systems
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13. Architecture
• Management and
visualization UI
• Processing engine
• RESTful API
• Shared Thing Data Model
• Time series data store,
meta data index for search,
message broker for real
time data processing
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14. WoTKit Processor
• multi-user real time IoT
data and service
mashup tool.
• Visual data flow
language for sensors
and services.
• See Web of Things
Workshop paper for
details
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15. CKAN Data Portal
• Driven by need for related
static data storage
• CKAN Open Data portal
platform used by many
governments
• publishers upload datasets
consisting of data resources
• API for search, up/
downloading data
• extensible with plugins
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16. HyperCat API Proxy
• Static Implementation - Imports
catalogues from underlying
systems to Solr.
• Out of date between imports
• Security: visibility and access
control logic
• Dynamic Implementation - Get
underlying catalogue on request
and filter as needed.
• Unify access control
• Address mismatch between
search semantics
• Scale of catalogue - paging
needed
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17. Smart Streets Experience
• In operation for 1 year ~64,000
sensor feeds
• Private and public data about
transportation and highways,
fixed assets and live sensors.
• Live road traffic, gully levels, air
quality, weather, flooding, fixed
asset: signs, roads, barriers,
parking locations, planned
roadworks.
• Sensors upload automatically via
APIs. Assets uploaded manually.
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18. Hub Applications
• ‘App store’ on the hub
landing site
• Developed by partner
companies and hackathon
• Catalog Explorer
• Roadworks Mashup
• Cycle Spot
• Accident reporter
• Pothole Prediction
• School Run …
https://smartstreets.sensetecnic.com/app-browse/
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19. Lessons
• UK project successful - innovation maintained while achieving a
minimal degree of interoperability
• Too early to standardize everything, need more experience and
to establish best practices first
• balance (proprietary) innovation and open standardization
• Cloud-hosted web-based hubs allow abstraction of connectivity
details and allowed us to pull together variety of sub-systems
and data services.
• Simple catalogue spec made it easier to agree, and provided
flexibility on the type and scope of ‘things’ exposed by hubs
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20. Conclusions
• Interoperability is critical to achieving widest variety of
applications and services in the IoT
• A web-centric, hub-based approach is a logical first step
toward allowing web developers to access ‘things’ and
associated data
• A key challenge is to unify hub catalogues, then thing data.
HyperCat is a good first step toward catalogue interoperability
• Tools such as the API Proxy can be used to address catalogue
and data interoperability while standards like HyperCat evolve
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21. More Information
• HyperCat:
http://www.hypercat.io/
http://wiki.1248.io/doku.php?id=hypercat!
• Smart Streets:
https://smartstreets.sensetecnic.com/
• WoTKit:
! ! http://wotkit.sensetecnic.com/!
• Sense Tecnic Systems: http://sensetecnic.com/ @sensetecnic!
• See demo and paper on distributed data flow at WoT Workshop
Thanks to Mark Duppenthaler, Daniel Yuen, Smart Streets IoT project Team - In Touch, Lancaster
University, Other 8 IoT hub projects - HyperCat specification, UK TSB, Canada NSERC
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