The software architecture of SCALEX is a typical three-tier architecture. These three layers are data layer, business logic layer and presentation layer. The two main functions of SCALEX are the creation of digitally enhanced exhibitions and the presentation of digital multimedia content to the exhibition visitors. The software architecture can thus be split into two main blocks, namely Exhibition Maker and Exhibition Visitor. Both blocks use a common data layer. On the exhibition maker side digital multimedia content is uploaded into the data layer and descriptive data, so called metadata, is added to classify the data. On the exhibition visitor side the digital content is presented to the visitors. There is one very important data flow, namely the circular flow of information between Storyliner, Player and Profiler. This information flow is used to adapt the presentation of content to the different visitor profiles Data Layer
The Data Layer is storing relevant information and data. Primarily, all digital multimedia content elements are stored in the data layer. These content elements can be text, images, videos or sounds and will be used for presenting them to the museums visitors. The Knowledge Editor is responsible bringing the data to the server. In addition to that the Knowledge Editor allows the exhibition creator to add metadata describing the content elements. The Storyliner also stores its rules and constraints in the data layer. Furthermore also the Profiler saves its profile information in the data layer. As a summary we can say that the following four data blocks are stored in the data layer:• Digital Multimedia Content
• Metadata describing the Digital Multimedia Content
• Rules and Constraints for the Storyliner
• Generic Group and Visitor Profile Information
The Business Logic Layer represents the logic of the overall system. It can be seen from two views, namely the exhibition maker or exhibition creator view and the exhibition visitor view. On the exhibition maker side there is only one block in the business logic layer. This block is the Knowledge Editor that is used for editing content metadata, rules and constraints for the Storyliner and generic group profiles. On the exhibition visitor side the Storyliner and Profiler components are part of the business logic layer. Presentation Layer
The Presentation Layer describes the presentation of the different components to the respective users. It can also be seen from two views, namely the exhibition maker or exhibition creator view and the exhibition visitor view. On the exhibition maker side there is the interface to the Knowledge Editor. On the exhibition visitor side the main interface is the so-called Player. The Player is responsible for showing the right digital multimedia content on the right display for the specified visitor.