Carlos Manuel Rodrigues Machado Autonomic Ubiquitous Computing

• Points: representing a single scalar value and its status – typically these map sensors,
actuators or configuration variables like a setpoint;
• Alarming: modelling, routing and acknowledgment of alarms. Alarms indicate a condition
which requires notification of either a user or another application;
• Histories: modelling and querying of time sampled point data. Typically edge devices collect
Bindings.
a time stamped history of point values which can be fed into higher level applications for
analysis.
The oBIX architecture consists in three main blocks or layers: Objects Model, Contracts and
The Object Model layer defines primitive blocks to model the systems behaviour semantics.
A contract is a list of all patterns to which a complex piece of data conforms. Contracts are
used to describe standardized structures such as points, historical trends and alarms; they are also
used to describe proprietary vendor data. The main point of the contract is that new ones can be
introduced without changing the oBIX schema. The bindings block consists in the HTTP/HTTPS1
protocols and SOAP2/WSDL3 that allow other devices to inter-connect between systems. It also
facilitates the system integrator applications, e.g., the deployment of a home automation system.
The role of the web service in oBIX is to guarantee the interoperability of home appliances.
Physical components such as sensors and actuators are not required to understand Web Services,
but their controllers are, as well as the new devices entering the home network. oBIX gateways also
need to understand web services in order to communicate with the outside world and coordinate
external services.
1 Hypertext Transfer Protocol over Secure Socket Layer (HTTPS) is a URI scheme used to indicate a secure
communication such as payment transactions and corporate information systems.
2 Simple Object Access Protocol (SOAP) is a protocol specification for exchanging structured information in the
implementation of Web Services in computer networks.
3 Web Services Description Language (WSDL) is an XML-based language that provides a model for describing Web
services.
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