Rigorous Definition and Use of Concepts and Standards Loosely Coupled Components Technology Independence

SANY D2.3.4 Specification of the Sensor Service Architecture V3 Doc.V3.1 Copyright © 2007-2009 SANY Consortium Page 28 of 233

4. Enterprise Viewpoint

4.1. Architectural Requirements

The architectural and iterative design approach as described in RM-OA, 2007 is taken as the basis for the specification of the SensorSA. The architectural principles that have guided the specification of the ORCHESTRA Architecture have been adapted and assessed specifically for service networks that include access to sensors and sensor-related information. The result is presented in the following sections.

4.1.1 Rigorous Definition and Use of Concepts and Standards

The SensorSA shall make rigorous use of proven concepts and standards in order to decrease dependence on vendor-specific solutions, help ensure the openness of a sensor service network and support the evolutionary development process of the SensorSA. Note: The SensorSA relies on the standard series “OGC Sensor Web Enablement SWE” Botts et al, 2006 as the starting point to refine the access and the management of sensor-related information.

4.1.2 Loosely Coupled Components

The components involved in a sensor service network shall be loosely coupled, where loose coupling implies the use of mediation to permit existing components to be interconnected without changes. Note: In this stringency, this architectural principle is restricted to the acquisition, application and user domains of a sensor service network see section 6.1 as its application in the sensor domain may not be possible due to the predominance of proprietary solutions. Furthermore, performance and dependability requirements may necessitate a sensor network with fixed communication relationships and tight coupling of the sensor components.

4.1.3 Technology Independence

The SensorSA shall be independent of technologies, their cycles and their changes as far as practically feasible. It must be possible to accommodate changes in technology e.g. lifecycle of middleware technology without changing the SensorSA itself. The SensorSA shall be independent of specific implementation technologies e.g. middleware, programming language, operating system. In general and if possible, the SensorSA shall not be influenced by or deal with limitations of specific implementation technologies. However, the SensorSA shall be explicitly designed such that it may deal with technical limitations of specific implementation technologies in the sensor domain see section 6.1. Note: Limitations of existing sensor networks must be taken into account in the SensorSA. At a minimum the characteristics of the sensor-to-sensor protocols must be considered in the meta-information e.g. dependability, quality of service, performance. This will be assessed in future versions of this document in more detail. SANY D2.3.4 Specification of the Sensor Service Architecture V3 Doc.V3.1 Copyright © 2007-2009 SANY Consortium Page 29 of 233

4.1.4 Evolutionary Development - Design for Change