Abstract
Communication of large data volumes is a core functionality of distributed systems middleware, namely, for interconnecting components, for distributed computation and for fault tolerance. This common functionality is however achieved in different middleware platforms with various combinations of operating system and application level protocols, both standardized and ad hoc, and including implementations on managed runtime environments such as Java. In this paper, in contrast with most previous work that focus on performance, we point out that architectural and implementation decisions have an impact in throughput stability when the system is heavily loaded, precisely when such stability is most important. In detail, we present an experimental evaluation of several communication protocol components under stress conditions and conclude on the relative merits of several architectural options.

Abstract

Abstract
MathIS is a new project that aims to reinvigorate secondary-school mathematics by exploiting insights of the dynamics of algorithmic problem solving. This paper describes the main ideas that underpin the project. In summary, we propose a central role for formal logic, the development of a calculational style of reasoning, the emphasis on the algorithmic nature of mathematics, and the promotion of self-discovery by the students. These ideas are discussed and the case is made, through a number of examples that show the teaching style that we want to introduce, for their relevance in shaping mathematics training for the years to come. In our opinion, the education of software engineers that work effectively with formal methods and mathematical abstractions should start before university and would benefit from the ideas discussed here.

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Abstract
Refinement by interpretation replaces signature morphisms by logic interpretations as a means to translate specifications and witness refinements. The approach was recently introduced by the authors [M. A. Martins, A. Madeira, and L. S. Barbosa. Refinement via interpretation. In Proc. of 7th IEEE Int. Conf. on Software Engineering and Formal Methods, Hanoi, Vietnam, November 2009. IEEE Computer Society Press] in the context of equational specifications, in order to capture a number of relevant transformations in software design, reuse and adaptation. This paper goes a step forward and discusses the generalization of this idea to deductive systems of arbitrary dimension. This makes possible, for example, to refine sentential into equational specifications and the latter into modal ones. Moreover, the restriction to logics with finitary consequence relations is dropped which results in increased flexibility along the software development process.

Abstract
Traditional notions of refinement of algebraic specifications, based on signature morphisms, art often too rigid to capture a number of relevant transformations in the context of software design, reuse and adaptation. This paper proposes an alternative notion of specification refinement, building on recent work on logic interpretation. The concept is discussed, its theory partially developed, its use illustrated through a number of examples.