Miguel Matos

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. Decidability results for hybrid(ised) logics.Generation of Hilbert calculi for hybrid(ised) logics.Generation of Tableau systems for hybrid(ised) logics.

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Software refactoring is a well-known technique that provides transformations on software artifacts with the aim of improving their overall quality. We have previously proposed a catalog of refactorings for spreadsheet models expressed in the ClassSheets modeling language, which allows us to specify the business logic of a spreadsheet in an object-oriented fashion. Reasoning about spreadsheets at the model level enhances a model-driven spreadsheet environment where a ClassSheet model and its conforming instance (spreadsheet data) automatically co-evolves after applying a refactoring at the model level. Research motivation was to improve the model and its conforming instance: the spreadsheet data. In this paper we define such refactorings using previously proposed evolution steps for models and instances. We also present an empirical study we designed and conducted in order to confirm our original intuition that these refactorings have a positive impact on end-user productivity, both in terms of effectiveness and efficiency. The results are not only presented in terms of productivity changes between refactored and non-refactored scenarios, but also the overall user satisfaction, relevance, and experience. In almost all cases the refactorings improved end-users productivity. Moreover, in most cases users were more engaged with the refactored version of the spreadsheets they worked with.

Wireless communication plays a critical role in determining the lifetime of Internet-of-Things (IoT) systems. Data aggregation approaches have been widely used to enhance the performance of IoT applications. Such approaches reduce the number of packets that are transmitted by combining multiple packets into one transmission unit, thereby minimising energy consumption, collisions and congestion. However, current data aggregation schemes restrict developers to a specific network structure or cannot handle multi-hop data aggregation. In this paper, we propose Hitch Hiker 2.0, a component binding model that provides support for multi-hop data aggregation. Hitch Hiker uses component meta-data to discover remote component bindings and to construct a multi-hop overlay network within the free payload space of existing traffic flows. Hitch Hiker 2.0 provides end-to-end routing of low-priority traffic while using only a small fraction of the energy of standard communication. This paper extends upon our previous work by incorporating new mechanisms for decentralised route discovery and providing additional application case studies and evaluation. We have developed a prototype implementation of Hitch Hiker for the LooCI component model. Our evaluation shows that Hitch Hiker consumes minimal resources and that using Hitch Hiker to deliver low-priority traffic reduces energy consumption by up to 32 {%}.

Model-driven engineering (MDE) is a software engineering approach based on model transformations at different abstraction levels. It prescribes the development of software by successively transforming the models from abstract (specifications) to more concrete ones (code). Alloy is an increasingly popular lightweight formal specification language that supports automatic verification. Unfortunately, its widespread industrial adoption is hampered by the lack of an ecosystem of MDE tools, namely code generators. This paper presents a model transformation from Alloy to UML class diagrams annotated with OCL (UML+OCL) and shows how an existing transformation from UML+OCL to Alloy can be improved to handle dynamic issues. The proposed bidirectional transformation enables a smooth integration of Alloy in the current MDE contexts, by allowing UML+OCL specifications to be transformed to Alloy for validation and verification, to correct and possibly refine them inside Alloy, and to translate them back to UML+OCL for sharing with stakeholders or to reuse current model-driven architecture tools to refine them toward code.

This paper proposes and validates a model-driven software engineering technique for spreadsheets. The technique that we envision builds on the embedding of spreadsheet models under a widely used spreadsheet system. This means that we enable the creation and evolution of spreadsheet models under a spreadsheet system. More precisely, we embed ClassSheets, a visual language with a syntax similar to the one offered by common spreadsheets, that was created with the aim of specifying spreadsheets. Our embedding allows models and their conforming instances to be developed under the same environment. In practice, this convenient environment enhances evolution steps at the model level while the corresponding instance is automatically co-evolved. Finally, we have designed and conducted an empirical study with human users in order to assess our technique in production environments. The results of this study are promising and suggest that productivity gains are realizable under our model-driven spreadsheet development setting.