SENSEI Sample Clauses

SENSEI. For the integration of the physical with the digital world, the SENSEI project6 creates an open architecture that especially addresses scalability problems for distributed wireless sensors and actuator networks. The architecture designed in this project allows for an easy and flexible plug and play integration of globally distributed sensors and actuators into a global system. A semantic description of devices aids to unify the view and access of distributed services and entities. Syntax and semantics of entities are contained in an advanced resource description, an ontology-based data representation with an RDF encoding. SENSEI, therefore differentiates between two main models, the information model and the resource model [66]: The information model developed in SENSEI defines three different abstraction layers for entity description namely raw data, observation and measurement and context information. Raw data solely describes a value of interest that is received from an entity. Observation and Measurement however, is defined to represent additional meta-information about the observed raw value. Context information introduces yet more relations to connect real world entities and represent their context. As such, SENSEI follows an entity-centric approach. These generic relations and concepts are designed to act as upper ontology for domain ontologies. In turn, the domain ontologies that base their definitions on the SENSEI upper ontology information model can be handled by the SENSEI system. Another model that is defined in the project is the resource model: All entities (sensors, actuators, processors) can be modelled as “resources” in SENSEI. Information about how a resource can be accessed, where it is located and what are its general functionalities is stored. The resource description that represents some of these properties is defined by the resource provider and stored in a so called resource directory where all static information of resources can be found. The specific operations of a resource are described in addition to the resource description. An additional semantic operation description can be associated with the definition of the operations and in turn describe inputs, outputs and functionalities of a specific resource operation in a machine-interpretable form. The SENSEI query mechanism uses the already mentioned resource directory and a so-called entity directory so that the relevant resources can be found. The entity directory hereby provi...