Towards improving the navigability of Web applications: a model-driven approach

Navigability, defined as the efficiency, effectiveness and satisfaction with which a user navigates through the system in order to fulfil her goals under specific conditions, has a definite impact on the overall success of Web applications. This quality attribute can be measured based on the navigational model provided by Web Engineering methodologies. Most of the measures currently defined for navigational models are tightly coupled with particular Web Engineering methodologies, however. Furthermore, modifications to the design of the navigational model, carried out with the aim of improving navigability, are performed manually. Both practices have seriously hampered the reusability and adoption of proposed navigability measures and improvement techniques. In this paper we present a Model-Driven Engineering approach to solving these problems. On the one hand, we propose a generic approach which defines navigability measurement models that can be integrated into any Web Engineering methodology. On the other hand, we present a model-driven improvement process for the navigational model design which incurs no increase in costs or in time-to-market of Web applications. This process is divided into two phases: evaluation (i.e. assessment of the model through objective measures) and evolution (i.e. transformation of the model when the measurement results do not accomplish certain quality decision criteria that have been defined previously).