User mobility and ubiquity are two key features for the information technology infrastructure. Our aim is to define an architecture that realizes the integration between a) a set of existing Internet/Intranet services, b) the services allowed by telecommunication network c) the applications and peripherals devoted to manage alarms and control industrial processes. The defined architecture permits to realize a simple exchange system that permits notification exchanges between different systems running on different platforms. This model is particularly suitable for environments that need strong personalization of the services, offered to users, in order to extend the existing services and to support the development of new ones.

The mobility of terminals and users is a crucial issue in the open global system represented by the Internet. Supporting terminal and user mobility requires a middleware infrastructure capable of efficiently answering the needs of scalable resource discovery, of security and interoperability, of Quality of Service (QoS) monitoring and adaptation. Some proposals address mobility at the network level and some others focus on application-level solutions. By following the latter approach, the paper proposes the adoption of the mobile agent technology to model and implement mobility. In particular, the paper concentrates on the components and modules implemented in the SOMA mobile agent programming framework to specifically support terminal and user mobility. The SOMA tracing and discovery system extends the SOMA basic naming service to identify and keep track of all mobile enti-ties in the environment. The SOMA QoS adaptation support ex-ploits the functionality of the SOMA monitoring tools and permits to dynamically adjust service provision in response to the changing network and nodes conditions. These features are integrated in a mobility add-on module that pursues also the goals of security and interoperability when moving users and roaming terminals.

In mobile computing environments, necessary data is replicated on mobile hosts during disconnections to improve availability. In order to minimize problems of inconsistency among data copies while maximizing the data update ability on disconnected sites, we propose an approach which controls database updates based on the probability that transactions occur and the duration of disconnection time between the sites. We derive a formula to choose the appropriate method between token and optimistic methods, and show that the proposed method works well even when the disconnection time deviates from the expected value.

We present the guidelines of a new project whose main task is to exploit mobile computers, connected via a Wireless Networks, in Personal Health systems, computerizing patient clinical records with sophisticated solutions for taking clinical information at the point of care.

In mobile computing environments, necessary data is replicated on mobile hosts during disconnections to improve availability. In order to minimize problems of inconsistency among data copies while maximizing the data update ability on disconnected sites, we propose an approach which controls database updates based on the probability that transactions occur and the duration of disconnection time between the sites. We derive a formula to choose the appropriate method between token and optimistic methods, and show that the proposed method works well even when the disconnection time deviates from the expected value.