IoT Semantics

Linked data

http://linkeddata.org/ Linked Data STRUCTURED DATA ON THE WEB

Resource Description Framework (RDF)

https://www.w3.org/RDF/

Json-ld

Json for linked data http://json-ld.org/

Things and Observations semantic

Semantic for things and the observations they produce can be defined using the Thing Types and Observation Types This configurable semantic in composed of :

• Type general info (name, description, geometric representation)
• Type specific properties
• In the case of the thing types, the set of observation types that the given thing type can produce

Each specific property contains its own semantic to define :

• Property data type; there are 3 kinds of property types

Select property type

• primitive types

Select primitive type

• collection things type
• collection/single things instances

Select thing instance

• Valid range or regular expression according to the data type
• Translation to the supported languages
• Limit of copies to keep for the property
• access control

Entity and Observations instances

Instances are resources of a specific semantic type, that have values for each property defined in the semantic.

Publishing semantic

Semantic for thing and observation types can be defined without letting others see the changes. The action of publishing a type is what makes it visible to other creators, thus available for use by others in their activities. Once published, a type can only be extended by its creator.

When a type is published:

• it becomes visible to other creators that will be able to use it in their activities
• its supported properties become visible to other creators
• supported properties can only be added as long as their are not required
• existing supported properties cannot be deleted.
• the type can be deleted only if it is not used by anyone
• values for the validation of the supported properties that are published cannot be changed : min value, max value, min date, max date and validation regex

public

*public types show this icon in the Tree editor

Resources status

When a thing instance does not meet the requirements imposed by the semantic of the type the status of the resource is invalid.

resource with invalid status do not returned as result of observers execution therefore are not taken into account by reasoners execution