Thesis full text (PDF) - Politecnico di Milano

the availability of one feature of a particular type of platform, while another model might be
fully committed to that type of platform [5].
Pervasive Services
Pervasive services are services available in a wide range of platforms [5]. In the MDA pervasive
services are modeled as platform independent. Examples are Directory services, Event handling,
Persistence, Transactions, and Security [6].
Application
The term application is used to refer to computer software delivering certain functionality.
Implementation
An implementation is a specification, which provides all the information needed to construct a
system and to put it into operation [5].
Model Transformation
Model transformation is the process of converting one model to another model of the same
system [5].
2.1.3 MDA in our Approach
The development of Web sites with a model-driven approach has been specifically addressed by
two important research projects, namely Araneus [7] and Strudel [8]. The first generation of
conceptual models for the Web [9][10][11][12][13][14][15] essentially considered Web
applications as a variant of traditional hypermedia applications, with the particularity that the
published contents are extracted from a database, and user interaction with the application takes
place via the medium of the Internet. Therefore, these modeling approaches have focused on
capturing the structure of the application contents, e.g., as a set of object classes or entities
connected by associations or relationships, and the navigation primitives, represented by such
concepts as pages, content nodes, and links. One such model is WebML, described in [15].
WebML allows specifying a Web site on top of existing data sources. A conceptual model
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