Implementing and adapting the WRON-RM Use Case categories for eReefs: Aiming for Interoperable Systems' requirements analysis best practice

Abstract

Multiple models, data services, sensor networks and other information tools are being embedded within complex and sometimes distributed architectures known as information platforms. These information platforms are increasingly being used to model multi-faceted environmental phenomena with one example being the eReefs project which will generate a near real-time view of lagoon water quality for the Great Barrier Reef. Not only may they involve many subsystems which must interoperate but they need to be able to evolve over time as new computational elements, sensor resources, models and datasets become available or cease to exist - for example a satellite's life ending. To cater for both interoperability and evolution, system design must enable Use Cases - certain system behaviour - beyond those typically expected by end users such as data discovery and use. Use Cases for system maintenance, new subsystem addition, subsystem deprecation and overall information platform augmentation must be envisaged, articulated and catered for. For institutionally distributed information platforms such as eReefs, overall management and governance Use Cases are also of particular importance. The Water Resources Observation Network's Reference Model (WRON-RM) provides the primary design framework for eReefs and it specifies six categories of Use Cases relevant to information platforms such as eReefs which were: 1. End User - processes of accessing information from an information platform 2. Data Provision - processes of contributing data to an information platform 3. Functionality Provision - processes of contributing data processing services 4. Enablement and Governance - processes of controlling various components 5. Cross-business Domain Integration - processes enabling integration with external systems 6. System Maintenance - processes associated with maintaining an information platform The WRON-RM is both incomplete and untested with its preface stating: “It was recognised that Use Cases described in the document did not fully reflect the WRON and that the true Use Cases for the WRON were not well understood. As such, considerable work was going to be necessary to discover, describe and analyse these Use Cases in order to understand their impact on the requirements of the WRON.” This paper details how, by designing eReefs, some of that required work has taken place and how through building a concrete implementation of the WRON-RM, the extent to which the categorisation of Use Cases has helped the project. Specifically we relate: how Use Cases received from stakeholders, including most subsystem designers, fitted into the six Use Case categories; how the information platform's Scoping Study (Car et. al., 2012) attempted to express Use Cases in all 6 categories; additions and modifications that have been made to these categories as functional requirements of eReefs have become clearer; specific Use Case examples from each generic category - the WRON-RM's six and additions and finally best practice methods regarding requirements gathering and stakeholder engagement for future information platforms attempting to provider similar functionality to eReefs.