Abstract
In a reconfigurable system, the response to contextual or internal change may trigger reconfiguration events which, on their turn, activate scripts that change the system's architecture at runtime. To be safe, however, such reconfigurations are expected to obey the fundamental principles originally specified by its architect. This paper introduces an approach to ensure that such principles are observed along reconfigurations by verifying them against concrete specifications in a suitable logic. Architectures, reconfiguration scripts, and principles are specified in ARCHERY, an architectural description language with formal semantics. Principles are encoded as constraints, which become formulas of a two-layer graded hybrid logic, where the upper layer restricts reconfigurations, and the lower layer constrains the resulting configurations. Constraints are verified by translating them into logic formulas, which are interpreted over models derived from ARCHERY specifications of architectures and reconfigurations. Suitable notions of bisimulation and refinement, to which the architect may resort to compare configurations, are given, and their relationship with modal validity is discussed.

Abstract
Hybridisation is a systematic process along which the characteristic features of hybrid logic, both at the syntactic and the semantic levels, are developed on top of an arbitrary logic framed as an institution. In a series of papers this process has been detailed and taken as a basis for a specification methodology for reconfigurable systems. The present paper extends this work by showing how a proof calculus (in both a Hilbert and a tableau based format) for the hybridised version of a logic can be systematically generated from a proof calculus for the latter. Such developments provide the basis for a complete proof theory for hybrid(ised) logics, and thus pave the way to the development of (dedicated) proof support.

Abstract
The complexity of modern software systems entails the need for reconfiguration mechanisms governing the dynamic evolution of their execution configurations in response to both external stimulus or internal performance measures. Formally, such systems may be represented by transition systems whose nodes correspond to the different configurations they may assume. Therefore, each node is endowed with, for example, an algebra, or a first-order structure, to precisely characterise the semantics of the services provided in the corresponding configuration. Hybrid logics, which add to the modal description of transition structures the ability to refer to specific states, offer a generic framework to approach the specification and design of this sort of systems. Therefore, the quest for suitable notions of equivalence and refinement between models of hybrid logic specifications becomes fundamental to any design discipline adopting this perspective. This paper contributes to this effort from a distinctive point of view: instead of focussing on a specific hybrid logic, the paper introduces notions of bisimilarity and refinement for hybridised logics, i.e. standard specification logics (e.g. propositional, equational, fuzzy, etc) to which modal and hybrid features were added in a systematic way. © A. Madeira, M.A. Martins & L.S. Barbosa.

Abstract
Lightweight formal methods ought to provide to the end user the rigorousness of mathematics, without compromising simplicity and intuitiveness. Alloy is a powerful tool, particularly successful on this mission. Limitations on the verification side, however, are known to prevent its wider use in the development of safety or mission critical applications. A number of researchers proposed ways to connect Alloy to other tools in order to meet such challenges. This paper's proposal, however, is not establishing a link from Alloy to another single tool, but rather to 'plunge' it into the Hets network of logics, logic translators and provers. This makes possible for Alloy specifications to 'borrow' the power of several, non dedicated proof systems. Semantical foundations for this integration are discussed in detail. © 2013 IEEE.

Abstract
This paper presents the encoding of the hybridisation method proposed in [MMDB11, DM13] into the Hets platform. © 2013 Springer-Verlag Berlin Heidelberg.

Abstract
As a complex artefact, software has to meet requirements formulated and verified at different levels of abstraction. A basic distinction is drawn between behavioural (dynamic) and data (static) aspects. From an educational point of view, although disguised under a number of different designations, both issues are usually present, but kept separated, in typical Computer Science undergraduate curricula. It is often argued that they tackle orthogonal problems through essentially different methods. This paper explores an alternative path in which students progress from equational to hybrid specifications in a uniform setting, integrating paradigms, combining data and behaviour, and dealing appropriately with systems evolution and reconfiguration.