CANopen is a truly open protocol that has not been developed by one company alone. Several working groups, consisting of many different device manufacturers and end-users, have co-operated to produce the CANopen standards, now under the supervision of the CAN in Automation organisation. CANopen has been produced as a result of EU funding. This article gives an overview of some of the fundamental concepts of CANopen communication and of CANopen implementation.

O crescimento dos parques de máquinas pessoais levanta consideráveis problemas de administração, contrastando com o que o ocorre com recursos centralizados. Nenhuma das soluções existentes para o efeito apresenta um compromisso aceitável entre a liberdade de configuração que se espera de uma máquina pessoal e o controlo eficiente dos recursos resultante de uma gestão centralizada. Neste contexto propõe se uma solução deste dilema através da coordenação de um sistema de boot remoto avançado com um conjunto de serviços de rede. A aplicação deste sistema à gestão e manutenção de laboratórios pedagógicos demonstrou que se pode assim criar um ambiente de ensino muito mais fiável e flexível do que o tradicional.

This paper describes CA/C++, Concurrency Annotations in C++, a language extension that regulates method invocations from multiple threads of execution in a shared-memory multiprocessor system. This system provides threads as an orthogonal element to the language, allowing them to travel through more than one object. Statically type-ckecked synchronous and asynchronous method invocations are supported, with return values from asynchronous invocations accessed through first class future-like objects. Method invocations are regulated with synchronization code defined in a separate class hierarchy, allowing separate definition and inheritance of synchronization mechanisms. Each method is protected by an access flag that can be switched in pre and post-actions, and by a predicate. Both must evaluate to true in order to enable a thread to animate the method code. Flags and method predicates are independently redefinable along the inheritance chain, thus avoiding the inheritance anomaly.

This paper presents a transformational approach to the derivation of implementations from model-oriented specifications of abstract data types.
The purpose of this research is to reduce the number of formal proofs required in model refinement, which hinder software development. It is shown to be applicable to the transformation of models written in META-IV (the specification language of VDM ) towards their refinement into, for example, PASCAL or relational DBMSs. The approach includes the automatic synthesis of retrieve functions between models, and data-type invariants.

The underlying algebraic semantics is the so-called final semantics ``à la Wand'': a specification ``is'' a model (heterogeneous algebra) which is the final object (up to isomorphism) in the category of all its implementations.

The transformational calculus approached in this paper follows from exploring the properties of finite, recursively defined sets.

This work extends the well-known strategy of program transformation to model transformation, adding to previous work on a transformational style for operation-decomposition in META-IV. The model- calculus is also useful for improving model-oriented specifications.

Plain Language Synopsis: This research applies model based engineering techniques to develop novel verification and hazard analysis methods, which help manufacturers establish the quality and safety in medical device user interface designs. Artifacts produced by these methods provide evidence for regulators to quickly and objectively assess the safety of devices' interaction with users.

Abstract: Designs of medical device Human Computer Interfaces (HCI) need to be robust and appropriately reactive to user actions. There is evidence that the HCI design of some devices on the market can cause use errors and erroneously process user input, which may subsequently lead to serious patient harm. Model based engineering (MBE) technology can be used to model HCI design decisions with mathematical precision. This technology can facilitate the development of HCI models that clearly define the device's interaction behavior with users; offering a formal (mathematical) basis to reason about and verify the safety of the design. Automatic tool support is available to facilitate such reasoning and verification activities. Tool artifacts provide manufacturers and regulators an objective and scientific basis for assessing the safety of medical device user interfaces. The authors have successfully applied MBE techniques to the analysis of medical device user interfaces in two studies. In the first study, automatic model extraction was applied to the user interface software of a marketed infusion pump to produce a model that resembles the pump's use interaction behavior. Automated formal proving on the model uncovered several design flaws in the pump's user interface that could lead to severe consequences including the pump ignoring key presses that might cause patient overdose. In the second study, the authors captured the user interface software design common in medical devices with a generic user interface model. Based on this generic model, a hazard analysis technique was proposed that integrates human cognition process models and general interaction design principles to guide more comprehensive and systematic identification of design flaws in user interfaces. Preliminary experiments showed that this hazard analysis technique can identify 3 times more software-related hazards in user interface designs, compared to standard hazard analysis techniques.