Service Discovery Protocols have been developed for applications to take advantages of services shared over networks. Each protocol provides a way for applications to ask for the type of services they need. In return, applications receive information about services that could fulfill their needs. However, such protocols do not supply enough support for dynamic environments involving interaction among persons, heterogenous devices, applications and files. Unlike applications, people expect to receive customized information about their identity, role, social relations, and even contextual variables (e.g., location). Thus, to provide a computational support that satisfies users' requirements in an accurate way, up to date information about the current conditions of the environment and the entities involved in it is fundamental. In this paper, we tackle the lack of a descriptive technique for resource discovery by proposing a carefully designed ontological approach.

An intelligent area integrates both Internet and Intranet software/hardware supports (from small embedded sensors to powerful and dynamic computing devices) to provide information about each artifact state (e.g., a power failure of the refrigerator) without user intervention. This technological sophistication can be achieved by means of service discovery systems, which allow services and users to discover, configure and communicate with other services and users. However, most of these systems only provide support for interaction between services and software clients. In order to cope with this limitation, the SEDINU system aims at supporting interactions between nomadic users and services managed by each organizational area. As users may move from one area to another to perform their tasks, this system also provides support for user-user interaction and cooperation under specific contexts (role, location and goals). This Web-based ubiquitous and cooperative working environment is enriched by a face recognition engine that allows to locate nomadic users.

A mechanism for synchronizing shared objects in a distributed system based on persistent, typed objects is presented. Synchronization constraints are expressed as separate control clauses and are factorized for a class of objects. The interference of this mechanism with inheritance and transactions is examined and solutions are proposed. Examples of synchronized objects are provided, and a semaphore-based implementation of the mechanism is described.>

This paper describes the design of a distributed object manager which allows several Smalltalk-80 systems to share objects over a local-area network. This object manager is based on the following principles: location transparency and uniform object naming, unique object representation and use of symbolic links for remote access, possibility of object migration and distributed garbage collection. A version of the object manager has been implemented and is currently being integrated on a two nodes configuration.