DEMOM-A description based media object data model

A description is given of the DEMOM media object data model, which aims at providing a uniform framework for managing different types of media data i.e. images, text, sound or graphics. According to DEMOM, media objects are defined as a class hierarchy of objects, i.e., images, text, sound, and graphics are subtypes of the general type media object. Representation-specific objects are regarded as subordinate types of the corresponding subtype, e.g., a SUN raster image in pixrect format is an instance of the subtype pixrect which is in turn a subtype of image. Using images as an example the authors discuss the media object hierarchy, the corresponding access operations, and implementation issues. Content-oriented search of media data on the basis of predicate calculus is considered as an essential part of DEMOM and hence briefly outlined. Finally, concerns related to the integration of alphanumeric and media objects are also included