The computing and networking capacities of today's wireless portable devices allow for ubiquitous services, which are seamlessly networked. Indeed, wireless handheld devices now embed the necessary resources to act as both service clients and providers. However, the ubiquitous networking of services remains challenged by the inherent mobility and resource constraints of the devices, which make services a priori highly volatile. This paper discusses the design, implementation, and experimentation of the ubiSOAP service-oriented middleware, which leverages wireless networking capacities to effectively enable the ubiquitous networking of services. ubiSOAP specifically defines a layered communication middleware that underlies standard SOAP-based middleware, hence supporting legacy Web Services while exploiting nowadays ubiquitous connectivity.

Service discovery is a critical functionality of emerging pervasive computing environments. In such environments, service discovery mechanisms need to (i) overcome the heterogeneity of hardware devices, software platforms, and networking infrastructures; and (ii) provide users with an accurate selection of services that meet their current requirements. To address these issues, we have developed the Multi- Protocol Service Discovery and Access (MSDA) middleware platform^2, which provides context-aware service discovery and access in pervasive environments. This paper primarily focuses on the design and implementation of the context-awareness support of MSDA. Context-awareness not only provides a more accurate service selection, but also enables a more efficient dissemination of service requests across heterogeneous pervasive environments. We present the design and prototype implementation of MSDA, along with experimental results that demonstrate the advantages derived by introducing context awareness.

Pervasive computing environments bring new challenges for client/service interactions due to the heterogeneity of both the interconnected networks and the middleware platforms used. In order for clients to truly benefit from all the networked services embedded into the environment, an innovative solution is required that overcomes both the lack of interoperability of the existing discovery and access protocols, and the limited interconnectivity between the different networks available at a location. This paper introduces the MUSDAC middleware platform that interoperates with existing middleware protocols, and manages the dissemination of service information in dynamic multi-network environments. A generic service is thus provided that enables clients to discover and interact with services in the entire environment. A prototype implementation of our platform is further presented, enabling us to demonstrate the flexibility of our approach

Pervasive environments bring new challenges for service management, as clients have to handle large collections of services offered by concurrent networks at their location, as well as services on networks in known remote locations. To enable service discovery in such service-rich environments, we introduce a multiprotocol service discovery (MSD) platform that interacts with existing SD protocols and extend their service descriptions with context information. Service information and discovery requests are then disseminated among interconnected networks based on service and network profiles.

The DART (Distributed Adaptive Run-Time) project is developing an adaptive software environment for general-purpose distributed applications. The goal of the project is to provide a software run-time system that allows application authors to quickly develop distributed software, such as network or World Wide Web software, without having to deal with the details of the distribution technology. DART compile-time and run-time components configure the application execution environments depending on hints provided with the application. An essential feature of the run-time component is its ability to reconfigure, or adapt itself, both to the application requirements and to the system and networking environment. To achieve both distribution and adaptation, we use meta-level object programming techniques and run-time monitoring.