O estudo da interacção entre crianças e computadores tem recebido atenção crescente nos últimos anos (ver, por exemplo, a série de conferências em Interaction Design and Children). A utilização de meios informáticos, quer para actividades educativas, quer para actividades de lazer (bem como a sua integração), tem um potencial genericamente reconhecido. No entanto, é necessário estudar de que forma as crianças interpretam e interagem com as interfaces se pretendemos desenvolver sistemas bem sucedidos.
O objectivo do estudo apresentado nesta comunicação consistiu exactamente em estudar o modo como crianças entre os 5 e os 7 anos de idade interagem com computadores. Tal como mencionado, existe já investigação nesta área, e alguns conjuntos de guidelines de desenho estão já publicados (por exemplo, Gilutz e Nielsen, 2002). A diferença entre o presente estudo e outras publicações reside na forma como os dados serão obtidos e nos próprios objectivos do estudo. A principal meta do método utilizado não é descobrir o que as crianças podem ou não fazer numa interface, mas sim os motivos pelos quais elas conseguem ou não utilizá-la.

This paper reports on the development of specific slicing techniques for functional programs and their use for the identification of possible coherent components from monolithic code. An associated tool is also introduced. This piece of research is part of a broader project on program understanding and re-engineering of legacy code supported by formal methods.

Program slicing is a well known family of techniques used to identify code fragments which depend on or are depended upon specific program entities. They are particularly useful in the areas of reverse engineering, program understanding, testing and software maintenance. Most slicing methods, usually oriented towards the imperatice or object paradigms, are based on some sort of graph structure representing program dependencies. Slicing techniques amount, therefore, to (sophisticated) graph transversal algorithms. This paper proposes a completely different approach to the slicing problem for functional programs. Instead of extracting program information to build an underlying dependencies' structure, we resort to standard program calculation strategies, based on the so-called Bird-Meertens formalism. The slicing criterion is specified either as a projection or a hiding function which, once composed with the original program, leads to the identification of the intended slice. Going through a number of examples, the paper suggests this approach may be an interesting, even if not completely general, alternative to slicing functional programs.

Java applets run on a Virtual Machine that checks code integrity and correctness before execution using a module called the Bytecode Verifier. Java Card technology allows Java applets to run on smart cards. The large memory requirements of the verification process do not allow the implementation of an embedded Bytecode Verifier in the Java Card Virtual Machine. To address this problem, we propose a verification algorithm that optimizes the use of system memory by imposing an ordering on the verification of the instructions. This algorithm is based on control flow dependencies and immediate postdominators in control flow graphs.

The subject of this paper is functional program transformation in the so-called point-free style. By this we mean first translating programs to a form consisting only of categorically-inspired combinators, algebraic data types defined as fixed points of functors, and implicit recursion through the use of type-parameterized recursion patterns. This form is appropriate for reasoning about programs equationally, but difficult to actually use in practice for programming. In this paper we present a collection of libraries and tools developed at Minho with the aim of supporting the automatic conversion of programs to point-free (embedded in Haskell), their manipulation and rule-driven simplification, and the (limited) automatic application of fusion for program transformation.

This paper introduces a generic semantic framework for component-based development, expressed in the unified modelling language UML. The principles of a coalgebraic semantics for class, object and statechart diagrams as well as for use cases, are developed. It is also discussed how to formalize the refinement steps in the development process based upon a suitable notion of behavior refinement. In this way, a formal basis for component-based development in UML is studied, which allows the construction of more complex and specific systems from independent components.

Over the last decade, software architecture emerged as a critical issue in Software Engineering. This encompassed a shift from traditional programming towards software development based on the deployment and assembly of independent components. The specification of both the overall systems structure and the interaction patterns between their components became a major concern for the working developer. Although a number of formalisms to express behaviour and to supply the indispensable calculational power to reason about designs, are available, the task of deriving architectural designs on top of popular component platforms has remained largely informal. This paper introduces a systematic approach to derive, from CCS behavioural specifications the corresponding architectural skeletons in the Microsoft .Net framework, in the form of executable C and C# code. The prototyping process is fully supported by a specific tool developed in Haskell. Keywords: Software architecture; prototyping; CCS; Net framework, in the form of executable C# and Cω code. The prototyping process is fully supported by a specific tool developed in Haskell.