Adding Multimedia Collections to the Dexter Model

The Dexter Model defines the notion of atomic components and composite components, but it does not prescribe, nor it suggests, any particular structure for composite components. This paper proposes a specific type of composite component, called "collection". A collection is a container holding several members. Collections can contain other collections (nested collections). Collections can be regarded as sets, but they can also have an inner structure. Collections can be created in several ways: manually, through queries, by operations on other collections, by exploiting links, etc. Collections introduce a navigational pattern, based on their structure, that is different from the standard node & link navigation. If active media are considered, collections allow the design and implementation of complex synchronisation strategies, difficult to obtain otherwise. The paper describes the motivations for using collections, their structure, their navigational capabilities and a number of possible authoring mechanisms. It also examines the interplay between standard navigation and collection navigation, possible synchronization strategies for collections, as well as the requirements for the definition of a mntime support (which could be used to extend the runtime layer of the Dexter Model).