Abstract
Software product lines (SPLs) are diverse systems that are developed using a dual engineering process: (a) family engineering defines the commonality and variability among all members of the SPL, and (b) application engineering derives specific products based on the common foundation combined with a variable selection of features. The number of derivable products in an SPL can thus be exponential in the number of features. This inherent complexity poses two main challenges when it comes to modelling: firstly, the formalism used for modelling SPLs needs to be modular and scalable. Secondly, it should ensure that all products behave correctly by providing the ability to analyse and verify complex models efficiently. In this paper, we propose to integrate an established modelling formalism (Petri nets) with the domain of software product line engineering. To this end, we extend Petri nets to Feature Nets. While Petri nets provide a framework for formally modelling and verifying single software systems, Feature Nets offer the same sort of benefits for software product lines. We show how SPLs can be modelled in an incremental, modular fashion using Feature Nets, provide a Feature Nets variant that supports modelling dynamic SPLs, and propose an analysis method for SPL modelled as Feature Nets. By facilitating the construction of a single model that includes the various behaviours exhibited by the products in an SPL, we make a significant step towards efficient and practical quality assurance methods for software product lines.

Abstract
Project-based learning offers a student centered pedagogy and a dynamic approach which promotes a deeper knowledge through real-world challenges and problems solving. The U.Openlab concept is developed at the University of Porto (U.Porto) in the context of the teaching/learning process and is assumed to be an interaction facilitator platform between real-world needs and practical works topics. The aim is to provide innovative answers and the effective use of assessment results, the credits recognition for future professional or scientific careers and a sustainable process oriented for, among others, universities heritage services' needs. The pilot-project in course at the University of Porto, focusing on the U.Porto Digital Museum, includes a technological infrastructure with three main components: several collections, an information and services management platform, with its corresponding digital repository; the U.Porto community contributions management platform (U.Porto OpenLab); and an adaptive framework that will support various interface applications with non-specific audiences. The U.Porto OpenLab considers two main areas: the bidding management area/calls for contributions and a contributions personal management area. The professor, the student and the "client" are the actors in the process. As for main tasks we point out the reception, selection and distribution of real needs/problems. Having concluded the assessment process, results were selected and an online publication was submitted. The inherent credits are recorded in a contributors' digital portfolio management and in the professional social networks profiles. The methodology will be presented and discussed as well as the process along with the obstacles and other factors contributing to the success and future replication of this experience.

Abstract
The wide number of languages and programming paradigms, as well as the heterogeneity of ‘programs’ and ‘executions’ require new generalisations of propositional dynamic logic. The dynamisation method, introduced in [20], contributed on this direction with a systematic parametric way to construct Many-valued Dynamic Logics able to handle systems where the uncertainty is a prime concern. The instantiation of this method with the Lukasiewicz arithmetic lattice over [0, 1], that we derive here, supports a general setting to design and to (fuzzy-) reason about systems with uncertainty degrees in their transitions. For the verification of real systems, however, there are no de facto methods to accommodate exact truth degrees or weights. Instead, the traditional approach within scientific community is to use different kinds of approximation techniques. Following this line, the current paper presents a framework where the representation values are given by means of intervals. Technically this is achieved by considering an ‘interval version’ of the Kleene algebra based on the [0, 1] Lukasiewicz lattice. We also discuss the ‘intervalisation’ of L action lattice (in the lines reported in [28]) and how this class of algebras behaves as an (interval) semantics of many-valued dynamic logic. © Springer International Publishing AG 2016.

Abstract
The number of everyday interconnected devices continues to increase and constitute the Internet of Things (IoT). Things are small computers equipped with sensors and wireless communications capabilities that are driven by energy constraints, since they use batteries and may be required to operate over long periods of time. The majority of these devices perform data collection. The collected data is stored on-line using web-services that, sometimes, operate without any special considerations regarding security and privacy. The current work proposes a modified hash-chain authentication mechanism that, with the help of a smartphone, can authenticate each interaction of the devices with a REST web-service using One Time Passwords (OTP) while using open wireless networks. Moreover, the proposed authentication mechanism adheres to the stateless, HTTP-like behavior expected of REST web-services, even allowing the caching of server authentication replies within a predefined time window. No other known web-service authentication mechanism operates in such manner

Abstract
Planning in education is a process that can determine the success of learning. This has major impact in engineering education, where students have to develop complex competences in order to make decisions that can influence the world and humankind. Teachers are reluctant regarding the effective practice of planning educational processes, identifying the lack of time and appropriate pedagogical training as main causes for the problem. Our aim is contribute to solve this problem. This paper presents the exploration of the capabilities of conceptualization of planning by the IMS-LD educational modelling language, through CADMOS authoring tool. To do so we used a learning object of a discipline of a Computer Engineering higher education course. Several specifications were made in CADMOS, based on different learning strategies common used in engineering education. The results show that IMS-LD and CADMOS can help and simplify the planning process for teachers, allowing them to implement changes, reuse and share planning products. Limitations were identified, but they do not preclude the use of the tool for planning.

Abstract
ReFlO is a framework and interactive tool to record and systematize domain knowledge used by experts to derive complex pipe-and-filter (PnF) applications. Domain knowledge is encoded as transformations that alter PnF graphs by refinement (adding more details), flattening (removing modular boundaries), and optimization (substituting inefficient PnF graphs with more efficient ones). All three kinds of transformations arise in reverse-engineering legacy PnF applications. We present the conceptual foundation and tool capabilities of ReFlO, illustrate how parallel PnF applications are designed and generated, and howdomain-specific libraries of transformations are developed.