Mobile and fixed telecommunications network operators have been experi M encing aggressive competition from Internet content providers that use the operators' infrastructure for providing subscribers with a wide choice of webbased mobile multimedia services. For keeping pace, operators designed and implemented strategies aimed at enabling the development of mobile services whose differentiation relies on their key strengths including call control, messaging, location, Presence, etc.

Even though some standardization initiatives enabling the homogeneous exposure of the mentioned functionality are already in place, considerable work still has to be done for easing the interaction with it on the service development side. The approach presented in this Dissertation aims at enhancing this interaction by proposing a context management platform that enables the developrnent of mobile services from a context awareness perspective.

Within the platform, a Context-Aware Service is conceptualized as a component implementing application logic mapping context notifications generated by Context Providers as result of events happening inside and outside the network into invocations of Service Capabilities implementing functionality aimed at triggering some actions based on the received context notifications.

Built on top of on well-known telecommunications concepts, the platform is based on a rniddleware approach for implementing fundamental context acquisition and management operations, and uses a Publish-Subscribe communication model between the cornponents implementing its key functionalities. Acknowledging the goals already achieved in the field of telecommunications feature exposure, the interfaces between Context-Aware Services and both Context Providers and Service Capabilities are based on the standardized and open Parlay aSA and Parlay X APIs.

For realizing the approach, a four-level service hierarchy is further defined, in which the components at each layer Implement key functionalities of the platform from a context management perspective. The validation of the design is achieved through the implementation of two proof-of-concept prototypes developed on top of JAIN SLEE and SIP Servlet Java container technologies.

With the aim of assessing the performance of the approach as a whole, the system is evaluated in two stages. While the first one is airned at benchmarking the performance of the control mechanisms provided by the underlying networking infrastructure, the second one verifies the operation of key mechanisms implementing the functionality of both Context Providers and Service Capabilities.