We describe a multi-agent platform for a traveller information system, allowing travellers to find the road traffic information web service (WSs) that best fits their requirements. After studying existing proposals for discovery of semantic WS, we implemented a hybrid matching algorithm, which is described in detail here. Semantic WS profiles are annotated semantically as an OWL-S and also the traveller request is represented as a OWL-S profile. The algorithm assigns different weights and measures to each advertised WS profile parameter, depending on their relevance, type and nature. To do this we have extended Paolucci’s Algorithm and adapted it to our scenario. We have added new similarity measures, in particular, the use of the ‘sibling’ relationship, to improve the recall, allowing relevant services to be discovered by the users yet not retrieved by other algorithms. Although we have increased the similarity concept relations, we have improved the run-time using a pre-process filter step that reduces the set of potentially useful WS. This improves the scalability of the semantic matching algorithm.

The interactions between the design of a computer's instruction set and the design of compilers that generate code for that computer have serious implications for overall computational cost and efficiency. This article, which investigates those interactions, should ideally be based on comprehensive data; unfortunately, there is a paucity of such information. And while there is data on the use of instruction sets, the relation of this data to compiler design is lacking. This is, therefore, a frankly personal statement, but one which is based on extensive experience. My colleagues and I are in the midst ofa research effort aimed at automating the construction of productionquality compilers. (To limit the scope of what is already an ambitious project, we have considered only algebraic languages and conventional computers.) In brief, unlike many compiler- compiler efforts of the past, ours involves automatically generating all of the phases of a compiler-including the optimization and code generation phases found in optimizing compilers. The only input to this generation process is a formal definition of the source language and target computer. The formulation of compilation algorithms that, with suitable parameters, are effective across a broad class of computer architectures has been fundamental to this research. In turn, finding these algorithms has led us to critically examine many architectures and the problems they pose. Much of the opinion that follows is based on our experiences in trying to do this, with notes on the difficulties we encountered.

e is an aspect-oriented hardware verification language that is widely used to verify the design of electronic circuits through the development and execution of testbenches. In recent years, the continued growth of the testbenches developed at Infineon Technologies has resulted in their becoming difficult to understand, maintain and extend. Consequently, a decision was taken to document the testbenches at a higher level of abstraction. Accordingly, we attempted to model our legacy test suites with an existing aspect-oriented modelling approach. In this paper we describe our experience of applying Theme/UML, an aspectoriented modelling approach, to the representation of aspectoriented testbenches implemented in e. It emerged that the common aspect-oriented concepts supported by Theme/UML were not sufficient to adequately represent the e language, primarily due to e’s dynamic, temporal nature. Based on this experience we propose a number of requirements that must be addressed before aspect-oriented modelling approaches such as Theme/UML are capable of representing aspect-oriented systems implemented in e.