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This service produces reliable software systems in contexts where correctness, responsiveness, robustness and security are essential. It develops integrated research in three lines: formal methods for software development, reliable distributed systems and information security.
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ItemAccelerating Deep Learning Training Through Transparent Storage Tiering( 2022) Dantas,M ; Leitao,D ; Cui,P ; Ricardo Gonçalves Macedo ; Liu,XL ; Xu,WJ ; João Tiago Paulo ; 5621 ; 6941
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ItemAdaptive Broadcast Cancellation Query Mechanism for Unstructured Networks( 2015) Lima,R ; Carlos Baquero ; Miranda,HThe availability of cheap wireless sensors boosted the emergence of unstructured networks using wireless technologies with decentralised administration. However, a simple task such as learning the temperature needs a discovery service to find a thermometer among all the sensors. In general, resource discovery relies on flooding mechanisms that waste energy and compromises system availability. Energy efficient strategies limit the exploration area, but with a significant impact on latency. The paper proposes ABC (Adaptive Broadcast Cancellation), a new algorithm that uses the knowledge acquired in previous discoveries to accelerate queries towards the resource. Knowledge is stored in a variation of Bloom filters, thus contributing for an efficient utilization of the sensors limited memory.
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ItemAdaptive database synchronization for an online analytical cioud-to-edge continuum( 2022) Costa,D ; José Orlando Pereira ; Ricardo Pereira Vilaça ; Faria,N ; 5635 ; 5602
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ItemAdding Records to Alloy( 2023) Nuno Moreira Macedo ; Alcino Cunha ; 5625 ; 5612Records are a composite data type available in most programming and specification languages, but they are not natively supported by Alloy. As a consequence, users often find themselves having to simulate records in ad hoc ways, a strategy that is error prone and often encumbers the analysis procedures. This paper proposes a conservative extension to the Alloy language to support record signatures. Uniqueness and completeness is imposed on the atoms of such signatures, while still supporting Alloy’s flexible signature hierarchy. The Analyzer has been extended to internally expand such record signatures as partial knowledge for the solving procedure. Evaluation shows that the proposed approach is more efficient than commonly used idioms. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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ItemAddressing Interactive Computing Systems' Concerns in Software Engineering Degrees( 2022) José Creissac Campos ; António Nestor Ribeiro ; 5599 ; 5639This paper arises from experience by the authors in teaching software engineering courses. It discusses the need for adequate coverage of Human-Computer Interaction topics in these courses and the challenges faced when addressing them. Three courses, at both licentiate and master's levels, are used as triggers for the discussion. The paper argues that the lack of relevant Human-Computer Interaction concepts creates challenges when teaching and learning requirements analysis, design, and implementation of software systems. The approaches adopted to address these challenges are described.
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ItemAddressing Interactive Computing Systems' Concerns in Software Engineering Degrees( 2021) José Creissac Campos ; António Nestor Ribeiro ; 5599 ; 5639This paper arises from experience by the authors in teaching software engineering courses. It discusses the need for adequate coverage of Human-Computer Interaction topics in these courses and the challenges faced when addressing them. Three courses, at both licentiate and master’s levels, are used as triggers for the discussion. The paper argues that the lack of relevant Human-Computer Interaction concepts creates challenges when teaching and learning requirements analysis, design, and implementation of software systems. The approaches adopted to address these challenges are described. © 2022, IFIP International Federation for Information Processing.
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ItemAddressing Interactive Computing Systems' Concerns in Software Engineering Degrees( 2021) José Creissac Campos ; António Nestor Ribeiro ; 5599 ; 5639This paper arises from experience by the authors in teaching software engineering courses. It discusses the need for adequate coverage of Human-Computer Interaction topics in these courses and the challenges faced when addressing them. Three courses, at both licentiate and master’s levels, are used as triggers for the discussion. The paper argues that the lack of relevant Human-Computer Interaction concepts creates challenges when teaching and learning requirements analysis, design, and implementation of software systems. The approaches adopted to address these challenges are described. © 2022, IFIP International Federation for Information Processing.
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ItemAn Adequate While-Language for Hybrid Computation( 2019) Renato Jorge Neves ; Goncharov,S ; 6181Hybrid computation harbours discrete and continuous dynamics in the form of an entangled mixture, inherently present in various natural phenomena and in applications ranging from control theory to microbiology. The emergent behaviours bear signs of both computational and physical processes, and thus present difficulties not only in their analysis, but also in describing them adequately in a structural, well-founded way. In order to tackle these issues and, more generally, to investigate hybridness as a dedicated computational phenomenon, we introduce a while-language for hybrid computation inspired by the fine-grain call-by-value paradigm. We equip it with operational and computationally adequate denotational semantics. The latter crucially relies on a hybrid monad supporting an (Elgot) iteration operator that we developed elsewhere. As an intermediate step, we introduce a more lightweight duration semantics furnished with analogous results and based on a new duration monad that we introduce as a lightweight counterpart to the hybrid monad.
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ItemAn Adequate While-Language for Hybrid Computation( 2019) Renato Jorge Neves ; Goncharov,S ; 6181
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ItemADSNARK: Nearly Practical and Privacy-Preserving Proofs on Authenticated Data( 2015) Backes,M ; Manuel Barbosa ; Fiore,D ; Reischuk,RMWe study the problem of privacy-preserving proofs on authenticated data, where a party receives data from a trusted source and is requested to prove computations over the data to third parties in a correct and private way, i.e., the third party learns no information on the data but is still assured that the claimed proof is valid. Our work particularly focuses on the challenging requirement that the third party should be able to verify the validity with respect to the specific data authenticated by the source - even without having access to that source. This problem is motivated by various scenarios emerging from several application areas such as wearable computing, smart metering, or general business-to-business interactions. Furthermore, these applications also demand any meaningful solution to satisfy additional properties related to usability and scalability. In this paper, we formalize the above three-party model, discuss concrete application scenarios, and then we design, build, and evaluate ADSNARK, a nearly practical system for proving arbitrary computations over authenticated data in a privacy-preserving manner. ADSNARK improves significantly over state-of-the-art solutions for this model. For instance, compared to corresponding solutions based on Pinocchio (Oakland' 13), ADSNARK achieves up to 25x improvement in proof-computation time and a 20x reduction in prover storage space.
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ItemAggregation protocols in light of reliable communication( 2017) Kassam,Z ; Ali Shoker ; Paulo Sérgio Almeida ; Carlos Baquero
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ItemAI for the Win: Improving Spectrum-based Fault Localization( 2012) Birgit Hofer ; Franz Wotawa ; Rui MaranhãoA considerable amount of time in software engineering is spent in debugging. In practice, mainly debugging tools which allow for executing a program step-by-step and setting break points are used. This debugging method is however very time consuming and cumbersome. There is a need for tools which undertake the task of narrowing down the most likely fault locations. These tools must complete this task with as little user interaction as possible and the results computed must be beneficial so that such tools appeal to programmers. In order to come up with such tools, we present three variants of the well-known spectrum-based fault localization technique that are enhanced by using methods from Artificial Intelligence. Each of the three combined approaches outperforms the underlying basic method concerning diagnostic accuracy. Hence, the presented approaches support the hypothesis that combining techniques from different areas is beneficial. In addition to the introduction of these techniq
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ItemAIDA-DB: A Data Management Architecture for the Edge and Cloud Continuum( 2022) Faria,N ; Costa,D ; José Orlando Pereira ; Ricardo Pereira Vilaça ; Ferreira,L ; Fábio André Coelho ; 6059 ; 5635 ; 5602
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ItemAJITTS: Adaptive just-in-time transaction scheduling( 2013) Alonso,A ; Rui Carlos Oliveira ; José Orlando PereiraDistributed transaction processing has benefited greatly from optimistic concurrency control protocols thus avoiding costly fine-grained synchronization. However, the performance of these protocols degrades significantly when the workload increases, namely, by leading to a substantial amount of aborted transactions due to concurrency conflicts. Our approach stems from the observation that when the abort rate increases with the load as already executed transactions queue for longer periods of time waiting for their turn to be certified and committed. We thus propose an adaptive algorithm for judiciously scheduling transactions to minimize the time during which these are vulnerable to being aborted by concurrent transactions, thereby reducing the overall abort rate. We do so by throttling transaction execution using an adaptive mechanism based on the locally known state of globally executing transactions, that includes out-of-order execution. Our evaluation using traces from the industry standard TPC-E workload shows that the amount of aborted transactions can be kept bounded as system load increases, while at the same time fully utilizing system resources and thus scaling transaction processing throughput. © 2013 IFIP International Federation for Information Processing.
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ItemAlloy Meets the Algebra of Programming: A Case Study( 2013) José Nuno Oliveira ; Ferreira,MARelational algebra offers to software engineering the same degree of conciseness and calculational power as linear algebra in other engineering disciplines. Binary relations play the role of matrices with similar emphasis on multiplication and transposition. This matches with Alloy's lemma "everything is a relation" and with the relational basis of the Algebra of Programming (AoP). Altogether, it provides a simple and coherent approach to checking and calculating programs from abstract models. In this paper, we put Alloy and the Algebra of Programming together in a case study originating from the Verifiable File System mini-challenge put forward by Joshi and Holzmann: verifying the refinement of an abstract file store model into a journaled (FLASH) data model catering to wear leveling and recovery from power loss. Our approach relies on diagrams to graphically express typed assertions. It interweaves model checking (in Alloy) with calculational proofs in a way which offers the best of both worlds. This provides ample evidence of the positive impact in software verification of Alloy's focus on relations, complemented by induction-free proofs about data structures such as stores and lists.
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ItemAMAN Case Study( 2023) José Creissac Campos ; 5599This document presents the case study for the ABZ 2023 conference. The case study introduces a safety critical interactive system called AMAN (Arrival MANager), which is a partly-autonomous scheduler of landing sequences of aircraft in airports. This interactive systems interleaves Air Traffic Controllers activities with automation in AMAN. While some AMAN systems are currently deployed in airports, we consider here only a subset of functions which represent a challenge in modelling and verification. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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ItemAMAN Case Study( 2023) José Creissac Campos ; 5599This document presents the case study for the ABZ 2023 conference. The case study introduces a safety critical interactive system called AMAN (Arrival MANager), which is a partly-autonomous scheduler of landing sequences of aircraft in airports. This interactive systems interleaves Air Traffic Controllers activities with automation in AMAN. While some AMAN systems are currently deployed in airports, we consider here only a subset of functions which represent a challenge in modelling and verification. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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ItemAMAN Case Study( 2023) José Creissac Campos ; 5599This document presents the case study for the ABZ 2023 conference. The case study introduces a safety critical interactive system called AMAN (Arrival MANager), which is a partly-autonomous scheduler of landing sequences of aircraft in airports. This interactive systems interleaves Air Traffic Controllers activities with automation in AMAN. While some AMAN systems are currently deployed in airports, we consider here only a subset of functions which represent a challenge in modelling and verification. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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ItemAnalysing interactive devices based on information resource constraints( 2014) José Creissac Campos ; Doherty,G ; Michael Douglas HarrisonAnalysis of the usability of an interactive system requires both an understanding of how the system is to be used and a means of assessing the system against that understanding. Such analytic assessments are particularly important in safety-critical systems as latent vulnerabilities may exist which have negative consequences only in certain circumstances. Many existing approaches to assessment use tasks or scenarios to provide explicit representation of their understanding of use. These normative user behaviours have the advantage that they clarify assumptions about how the system will be used but have the disadvantage that they may exclude many plausible deviations from these norms. Assessments of how a design fails to support these user behaviours can be a matter of judgement based on individual experience rather than evidence. We present a systematic formal method for analysing interactive systems that is based on constraints rather than prescribed behaviour. These constraints capture precise assumptions about what information resources are used to perform action. These resources may either reside in the system itself or be external to the system. The approach is applied to two different medical device designs, comparing two infusion pumps currently in common use in hospitals. Comparison of the two devices is based on these resource assumptions to assess consistency of interaction within the design of each device.
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ItemAnalysis of FLOSS communities as learning contexts( 2012) Luís Soares Barbosa ; António Cerone ; Sara Santos FernandesIt can be argued that participating in Free/Libre Open Source Software (FLOSS) projects can have a positive effect in the contributor's learning process. The need to collaborate with other contributors and to contribute to a project can motivate and implicitly foster learning. In order to validate such statements, it is necessary to (1) study the interactions between FLOSS projects' participants, and (2) explore the didactical value of participating in FLOSS projects, designing an appropriate questionnaire asking FLOSS contributors about their experience in FLOSS projects. In this paper, we illustrate how this questionnaire was designed and disseminated. We conclude the paper with results from 27 FLOSS projects contributors, determining that, not only they contribute and collaborate to the project and its community, but also that FLOSS contributors see that this type of activity can be regarded as a complement to formal education.