A dynamic manifestation approach for providing universal access to digitallibrary objects

Digital libraries are concerned with the creation and management of informa tion sources, the movement of information across global networks, and the e ffective use of this information by a wide range of users. A digital librar y is a vast collection of objects that are of multimedia nature, e.g., text , video, images, and audio. Users wishing to access the digital library obj ects may possess varying capabilities, preferences, domain expertise, and m ay use different information appliances. Facilitating access to complex mul timedia digital library objects that suits the users' requirements is known as universal access. In this paper, we present an object manifestation app roach in which digital library objects automatically manifest themselves to cater to the users' capabilities and characteristics. We provide a formal framework, based on Petri nets, to represent the various components of the digital library objects, their modality and fidelity, and the playback sync hronization relationships among them. We develop methodologies for object d elivery without any deadtime under network delays.