Cristóvão Oliveira

AGILE: Software Architecture for Mobility.

Architecture-based approaches have been promoted as a means of controlling the complexity of system construction and evolution, in particular for providing systems with the agility required to operate in turbulent environments and to adapt very quickly to changes in the enterprise world. Recent technological advances in communication and distribution have made mobility an additional factor of complexity, one for which current architectural concepts and techniques can be hardly used. The AGILE project is developing an architectural approach in which mobility aspects can be modelled explicitly and mapped on the distribution and communication topology made available at physical levels. The whole approach is developed over a uniform mathematical framework based on graph-oriented techniques that support sound methodological principles, formal analysis, and refinement. This paper describes the AGILE project and some of the results gained during the first project year.

Modelling the GSM Handover Protocol in CommUnity

CommUnity is a formal approach to software architecture. It has a precise, yet intuitive mathematical semantics based on category theory. It supports, at the methodological level, a clear separation between computation, coordination, and distribution (including mobility). It provides a simple state-based language for describing component behaviour that is inspired by Unity and Interacting Processes. It also addresses composition as a first class concern and accounts for the emergence of global system properties from interconnections. This paper describes the approach and available tool support by modelling essential aspects of the GSM handover protocol. We also sketch a framework that we are implementing for the distributed execution of such specifications using Klava, a Java library for mobile agent systems based on tuple spaces.

Towards an architectural approach to location-aware business process

We present first steps towards modelling location-aware business processes based on architectural primitives that support the separation of three important concerns: computation, coordination, and distribution. We focus in particular on the primitives that bring the expressive power of architectural connectors to the modelling of activity flows according to given business rules. Coordination primitives externalise, from business rules, the way business entities interact within given business activities. Location primitives externalise the dependencies that such rules put on the way activities are distributed and performed across communication networks.

A Model-Driven Approach to Extract Views from an Architecture Description Language

A common approach to defining architectural views is to have independent heterogeneous representations that are tailored to each views purpose, but this makes reconciling views into an overall architectural description harder. In this paper we put forward a complementary (not alternative) approach in which some views are derived from a given architecture description language (ADL) in a systematic way, by listing the design questions each view should answer. The approach is based on constructing the languages metamodel and extending it with the entities and associations needed to capture and explicitly relate the required views.

An architectural approach to mobility - the handover case study

Community is a formal approach to software architecture. Its main characteristics are: a precise, yet intuitive mathematical semantics based on categorical diagrams; a clear separation between computation, coordination, and distribution (including mobility); and a simple state-based language, inspired by Unity, to describe behaviour. This paper discusses the applicability of this approach to location-aware systems through the modelling of the GSM handover protocol, namely the way communication with a moving cellular phone passes from one station to another. The case study was developed with the Community Workbench, a tool that animates distributed and mobile architectural models.

The CommUnity Workbench

CommUnity is a formal approach to Software Architecture with a strict separation of the computation, coordination, and distribution aspects. The approach is based on a parallel design language with state, which facilitates the specification of computations compared to the process calculi used by other formal approaches, and on category theory, which provides an intuitive yet precise graph-based semantics for the configuration of components and connectors. The CommUnity Workbench is being developed as a proof of concept of the CommUnity framework, providing a graphical integrated development environment to write components, draw configurations, and execute the resulting system.