Abstract
The detection of volatile organic compounds is accomplished with a sensing device based on a long period fiber grating (LPFG) coated with a zinc oxide (ZnO) thin layer with self-temperature compensation. The ZnO coating structure was produced onto the cladding of the fiber by thermal oxidation of a metallic Zn thin film. The morphological characterization of ZnO thin films, grown at the same time on silicon substrates, was performed using X-ray diffraction, X-ray Photoelectron Spectroscopy and Scanning Electron Microscope which shows very good agreement. LPFGs with 290 nm thick ZnO coating were fabricated and characterized for the detection of ethanol and hexane in vapor phase. For ethanol a sensitivity of 0.99 nm / g.m(-3) was achieved when using the wavelength shift interrogation mode, while for hexane a much lower sensitivity of 0.003 nm / g.m(-3) was measured, indicating a semi-selectivity of the sensor with a spectral resolution better than 3.2 g.m(-3).

Abstract
The increase of distributed energy resources, mainly based on renewable sources, requires new solutions that are able to deal with this type of resources' particular characteristics (namely, the renewable energy sources intermittent nature). The smart grid concept is increasing its consensus as the most suitable solution to facilitate the small players' participation in electric power negotiations while improving energy efficiency. The opportunity for players' participation in multiple energy negotiation environments (smart grid negotiation in addition to the already implemented market types, such as day-ahead spot markets, balancing markets, intraday negotiations, bilateral contracts, forward and futures negotiations, and among other) requires players to take suitable decisions on whether to, and how to participate in each market type. This paper proposes a portfolio optimization methodology, which provides the best investment profile for a market player, considering different market opportunities. The amount of power that each supported player should negotiate in each available market type in order to maximize its profits, considers the prices that are expected to be achieved in each market, in different contexts. The price forecasts are performed using artificial neural networks, providing a specific database with the expected prices in the different market types, at each time. This database is then used as input by an evolutionary particle swarm optimization process, which originates the most advantage participation portfolio for the market player. The proposed approach is tested and validated with simulations performed in multiagent simulator of competitive electricity markets, using real electricity markets data from the Iberian operator-MIBEL.

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