he objective of Model-Driven Engineering (MDE) is to decouple the functionality and the behavior of applications from the technology and platforms they run on, by automatic transformation of system models. The goal of the OMG MDA initiative is to standardize the modeling and the model transformation process. The MDA therefore proposes a standard architecture for MDE based on the UML. The MDA introduces the concept of Platform Independent Models (PIM), which can automatically or semi-automatically be mapped to different Platform-specific Models (PSM) of the system.  Finally, code can be generated from PSM’s and other deployment artifacts.

The PIM’s define the functionality and behavior of a system independently of the specific technologies that implement it. The key point here is that PIM’s are not supposed to address technological considerations. In the large sense, technological are aspects of a solution to the problem rather than aspects of the original problem. Many of these concerns such as authentication, caching or logging have a crosscutting nature.

Model weaving provides a more flexible solution to the integration of these concerns than general model transformation:
1.        Aspects provide a modular way to express a model transformation with respect to a particular concern.
2.        Aspects enable model transformations to be expressed in terms of the model entities to be transformed, as opposed to QVT queries which are expressed in terms of meta-model entities.