resource discovery in iot: current trends, gap analysis ...€¦ · soumya kanti datta research...
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Resource Discovery in IoT: Current Trends, Gap Analysis and Future Standardization Aspects
Soumya Kanti DattaResearch Engineer, EURECOM
TF-DI Coordinator in W3C WoT IGEmail: [email protected]
Roadmap
� Introduction
� Current Discovery Landscape
� Gap Analysis from Standards Point-of-View
� Search Engine Based Resource Discovery
� Inputs to SDOs
� Conclusion
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Introduction: Discovery
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� Search functionalities provided to Humans
�Yahoo
�Bing
� Search Engine for things?
Source : www.iotdex.com
Two Main Aspects to Consider
� Discovery mechanism is incomplete without retrieving and ranking information.
� Retrieve
� Thing description (including properties and capabilities).
� Thing metadata.
� Rank
� Depending on context rank the retrieved information.
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� Discovery for humans
� Looking for a thing/M2M service providing offline map of Milan.
� Can be assisted by a search engine.
� M2M discovery
� With no human in the loop
� It is one of the challenges.
� E.g. - M2M gateway looking for actuators to set a room temperature (smart living service).
Category 1: Search around ME
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� This category of discovery includes technologies that allow to discover things around me (in a spatial sense)� NFC
� UriBeacon (Formerly known as Physical Web from Google)
� iBeacon (from Apple)
Sources -
https://www.w3.org/WoT/IG/wiki/Discovery_Categories_and_Tech_Landscape
https://github.com/w3c/wot/blob/master/TF-DI/Interactions.md
Category 2: Search on My Network
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� It covers technologies enabling discovery of things on the network.
� mDNS
� SSDP
Category 3: Searching in a Directory
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� A central directory is used for discovery of things and resources
� Discovery requests are sent to the directory.� CoRE Resource
Directory� XMPP IoT Discovery� SPARQL Endpoints
Category 4: Search Across Peers
� In P2P style discovery, the directory is essentially distributed across the peers.
� Distributed hash tables (DHT) is often used to map the search space into a numeric range and then allocates servers to parts of that range.
� Observation: the technique works well for scale free networks.
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Category 5: Search for Thing Metadata
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� Once a “thing" has been discovered with mentioned mechanisms� next "resources" (thing
metadata) access at thing level
needs to be performed
� Examples� CoAP + CoRE Link Format (for
thing metadata)
� Sensor Observation Service
(SOS): it is a web service which
allows querying sensor
metadata.
Category 6: Semantic Based Search
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� Semantic Enhanced Service Proxy Framework for Internet of Things * � A semantic based framework using the concept of service
advertisement of a smart thing & eases service registration
� The advertisement contains a service metadata including name, id, endpoint, location and semantic annotation link.
� An evaluation of semantic service discovery of a U-city middleware **� It proposes a middleware which performs SD using semantic web
technologies on the contextual information inferred from sensor data.
* http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5724875
** http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5440391
Gap Analysis
� No common catalogue to describe the resources, units and domains.
� Synonyms are often not recognized. (Rain and Precipitation sensors)
� Therefore, searching for a resource using a synonym might not discover the
resource.
� No uniform ranking of discovered resources.
� Secure Discovery: how to integrate security mechanisms and access control functions into a discovery framework.
� Lack of uniform mechanism for resource discovery.
� Semantic based discovery is not studied in depth yet.� Extract contexts or key words to be used in discovery.
� How semantics could play a role in maintaining interoperability across IoT platforms.
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Search Engine Based Discovery Framework
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The Three Layers (1/2)
� Proxy layer
� Enable discovery and interaction with smart and legacy things regardless of
communication technology and protocols.
� Discovery layer
� Configuration registry: manages registration, un-registration of things and
provides storage of configurations.
� Indexing API: registered things are indexed to expedite the search
operation.
� Search engine
– Receives the discovery request (keywords/parameters) from clients
– Extracts indices
– Provides look up facility (discovers the matching things)
– Ranks the results based on relevance, availability, access control policies.
� Lifetime: A time period through which resources remain discoverable
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The Three Layers (2/2)
� Service enablement layer
�Exposes discovery layer functionalities through RESTful
web services.
�Enforces strict access control policies.
�Provides subscription and notification facilities.
� Includes semantic components for discovery.
� Incorporate security mechanisms
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Suggestions to SDOs
� Examine how semantics can solve interoperability issues.
� Need uniform and technology independent discovery for higher layer applications.
� Provide guidelines for binding to APIs and protocols for efficient interaction with things.
� Utilize a uniform catalogue of descriptions (as defined in things description) for discovery of things and their metadata.
� Provide means of ranking the discovery results
� When presented to end users or other M2M applications.
� Integrate strong access control policies and security mechanisms.
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Conclusion
� In a nutshell,
� Categorization of discovery mechanisms & interaction patterns.
� Gap analysis from standards perspective
� A search engine based discovery framework
� Suggestions to SDOs.
� A peek into the future works
� Deploying at a cloud to be used in a smart city framework
� Deploy in my soon-to-be smart apartment.
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Thank you!
� Email: [email protected]
� Telephone: +33658194342
� Twitter: @skdatta2010
� Webpage: http://www.eurecom.fr/en/people/datta-soumya-kanti
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