Universal access architecture for digital libraries

In this paper we present a universal access architecture for digital libraries. Our architecture supports traditional fixed clients and mobile clients addressing the connection adaptation and limited resources challenges presented by mobile devices. We describe the requirements of universally available personal digital libraries and illustrate their applicability with a user scenario. These requirements are addressed by our universal access architecture, which targets to support multiple device access, including mobile devices. The main components of the architecture are the Client-Side Applications, the Data Server and the Mobile Communication Middleware (MCM). Our work has focused on the mobile connection support provided by the interaction of mobile clients with the MCM, obtaining a constant response rate in spite of variability of network conditions. The architecture of a mobile software client that benefits from these mechanisms is described and supplemented with implementation notes showing how-in spite of the limited computing resources of mobile devices-it can interact with a data server that has not been designed to support client mobility via adaptation techniques implemented in a middleware.