Relationship to the Web of Things

[draggett]

The Web of Thinks seeks to overcome the fragmentation of the IoT through an abstraction layer that sits well above the details of the myriad IoT technologies and standards.

The Web of Things associates URIs with things that stand for sensors, actuators or related information services. These URIs can be used for RDF/Linked Data descriptions of the kinds of things, their relationships and the context in which they reside. Things are exposed to applications as software objects with properties, actions and events, described in a platform neutral way using JSON-LD and JSON Schema. This decouples developers from the details of the underlying networking technologies.

This points to an opportunity to more closely connect RDF with object oriented descriptions, n-ary terms, and Property Graphs

Some observations:

• Many developers are familiar with JSON but not with RDF and Linked Data
• Property names are locally scoped to the thing as you would expect in object oriented programming languages
• In the Web of Things, properties can have sub-properties and so forth, just as in Property Graphs
• You can associate metadata with things, properties, actions and events, e.g. data types, data constraints, units of measure and so forth
• You can distinguish between properties and other kinds of metadata
• You can describe how to interact with things via updating property values, invoking actions and listening for events
• JSON Schema isn't ideal, e.g. it doesn't directly allow you to specify things as first class types that can be used for property values, passed to and from actions, or passed with events, and there isn't a direct way to distinguish a value as a link except as a property that has a string value and is typed as a link.
• Likewise, there isn't a direct way to annotate the link except as an annotation on the property rather than the value
• As yet there are no proposals for rule languages for the Web of Things, although it is possible to use RDF shape rules in SHACL etc. to express constraints on things.

Further work could address these limitations in a way that is easy to use by the vast majority of developers without the need to be aware of the details of the RDF core that underpins it.

[VladimirAlexiev]

@draggett you won me at the diagram :-) I wish there was some way for me to work on WoT