Reuse-based layering: a strategy for architectural frameworks for learning technologies

Efforts to develop standards for learning technologies have developed along two distinct strands: standards for data and information models; and standards for components, interfaces and architectures. Standards relating to architectural frameworks are less well developed, and responsibility for decisions concerning system architecture has been left largely in the hands of developers of proprietary software such as learning management systems. There is growing interest in the development of standards for open architectural frameworks, based on layering, a decomposition technique which is in widespread use in software development. As interoperability and reusability are key concerns for developers of e-learning systems, the choice of an appropriate layering strategy is crucial, and this paper illustrates how a reuse-based layering strategy (as opposed to a more typical responsibility-based strategy) might be applied to e-learning systems in order to enhance reuse and interoperability.