Abstract
Contrary to outdoor positioning and navigation systems, there isn't a counterpart global solution for indoor environments. Usually, the deployment of an indoor positioning system must be adapted case by case, according to the infrastructure and the objective of the localization. A particularly delicate case is related with persons who are blind or visually impaired. A robust and easy to use indoor navigation solution would be extremely useful, but this would also be particularly difficult to develop, given the special requirements of the system that would have to be more accurate and user friendly than a general solution. This paper presents a contribute to this subject, by proposing a hybrid indoor positioning system adaptable to the surrounding indoor structure, and dealing with different types of signals to increase accuracy. This would permit lower the deployment costs, since it could be done gradually, beginning with the likely existing Wi-Fi infrastructure to get a fairy accuracy up to a high accuracy using visual tags and NFC tags when necessary and possible. © 2018 AISTI.

Abstract
Applying ethical principles to research is essential to ensure both participants’ universal rights and data quality. From the ethical point of view, researching with children poses additional challenges in designing the research, collecting and analysing data. The ethical principles generally accepted in scientific research are complementary, yet presenting conflicts that must be anticipated and mitigated by the researcher. This article explores the application of ethical principles in research with children, considering the different stages of research and both quantitative and qualitative research, proposing a set of six ethical principles to be applied before, during, and after the collection of data. The text includes examples from research adopting a mixed-method approach which involved 779 participants aged 7 to 15 years old. The study demonstrates that there is a strong interdependence among ethical principles applicable to research with children, not devoid of contradictions. Even widely accepted principles such as informed consent are complex and multifaceted. Moreover, the adoption of mixed methodology, in this particular case, has proven to be able to create ethic synergies, making the research globally more balanced. © Springer International Publishing AG 2018.

Abstract
This article revisits the inverted pendulum-in particular, analyses a simplified model of a Segway, with a view to exploring its capabilities in Control Systems Engineering education. The integration between the theoretic and practical side is achieved through simulation, and in particular by using MathWorks software. We also present a structure for the work to be done in the Laboratory class and propose a solution for the problem. © 2018 IEEE.

Abstract
This paper addresses the wind farm contribution in frequency control during the integration in the power grid. In the proposed model, the wind farm utilizes inertia control and droop control techniques with the purpose of improving the frequency regulation. In order to achieve optimal results, all the parameters of the controllers for the different units in the power grid are obtained by using a particle swarm optimization algorithm (PSO) and by introducing a modified objective function instead of a conventional objective function e.g., Integral Time-weighted Absolute Error (ITAE). Also, different constraints such as reheat turbine, time delay, governor dead band and generation rate constraint (GRC) are considered for thermal and hydro units with the aim of studying a more realistic power system, which is the main contribution of this paper when compared to the other works in this field. It is shown that, in case of a perturbation in power demand, the system frequency will recover quickly and effectively in comparison with the traditional approaches. In addition, a sensitivity test is carried out in a single power grid area in order to examine the effectiveness of the proposed approach. Then, the system is extended to a multi-area power system using a multi-terminal HVDC for further investigation of the suggested strategy. Simulation results are presented in order to assess the performance of the proposed approach in the power system.

Abstract
The presented research explores four years of newcomer engineering students at FEUP, one of the largest faculties of engineering in Portugal. The students are surveyed in a mandatory course common to all engineering programs at the mentioned faculty, totalling an involvement of about four thousand. This research explores the perceptions of 1198 newcomer students regarding learning and satisfaction, workload, integration into academic work environment and institutional support whilst trying to find gender differences regarding the following variables: engineering program, academic year and change of residence. The questionnaire used in the presented research was validated and its internal consistency was excellent. The findings reveal that students' perceptions on learning and satisfaction as well as on institutional support (two out of four factors) are consistently similar between genders throughout the four years of the study. The differences found between male and female students on integration and workload, however consistent, are small if not marginal. The study is significant because it shows the relevance of the optimization efforts for integration (in the academic work environment) introduced in a mandatory course at the start of engineering degrees in order to bridge the gap between male and female students. This research shows that we are walking towards gender equality in engineering, but we feel that there is still some effort to be done, namely through inspiring scholars to analyse and act upon academic contexts and higher education governance without prejudice and with an open mind: a commitment that is as hard as necessary.

Abstract
The Brazilian electricity market is characterized by having around 65% of its installed capacity coming from hydropower plants, with multiple agents coexisting in the same hydro cascades. Currently, it also contains certain peculiarities that distinguish it from other markets, such as the Energy Reallocation Mechanism (MRE), a centerpiece of the Brazilian market's design. This paper proposes replacing the MRE with a bid-based short-term market called the virtual reservoir model. To simulate the behavior of the hydros in this new market, an agent-based model is implemented using the reinforcement Q-learning algorithm, simulated annealing and linear programming. In the simulations, we use real data - encompassing more than 98% of the total hydro installed capacity and three years of market data - from the Brazilian power system. The results indicate that the management of (virtual) reservoirs can be the responsibility of each hydro: these can save water according to their own risk perceptions, while maintaining current efficiency and security levels. The results also suggest that the final monthly short-term market prices can substantially decrease in comparison with the current prices.