Abstract
Face and fingerprint are, currently, the most thoroughly explored biometric traits, promising reliable recognition in diverse applications. Commercial products using these traits for biometric identification or authentication are increasingly widespread, from smartphones to border control. However, increasingly smart techniques to counterfeit such traits raise the need for traits that are less vulnerable to stealthy trait measurement or spoofing attacks. This has sparked interest on the electrocardiogram (ECG), most commonly associated with medical diagnosis, whose hidden nature and inherent liveness information make it highly resistant to attacks. In the last years, the topic of ECG-based biometrics has quickly evolved toward the commercial applications, mainly by addressing the reduced acceptability and comfort by proposing new off-the-person, wearable, and seamless acquisition settings. Furthermore, researchers have recently started to address the issues of spoofing prevention and data security in ECG biometrics, as well as the potential of deep learning methodologies to enhance the recognition accuracy and robustness. In this paper, we conduct a deep review and discussion of 93 state-of-the-art publications on their proposed methods, signal datasets, and publicly available ECG collections. The extracted knowledge is used to present the fundamentals and the evolution of ECG biometrics, describe the current state of the art, and draw conclusions on prior art approaches and current challenges. With this paper, we aim to delve into the current opportunities as well as inspire and guide future research in ECG biometrics.

Abstract
Considering the importance associated with e-commerce website accessibility and usability, a study on one of the most relevant Portuguese e-commerce websites has been performed using both automatic and manual assessment procedures. In an initial stage, we evaluated the chosen website with a Web accessibility and usability automatic tool called SortSite; after that, we performed a manual evaluation to verify each previously detected error and present possible solutions to overcome those faults. In a third phase, three usability specialists have been used to perform a heuristic evaluation of the chosen website. Finally, user tests with blind people were carried out in order to fully assess the compliance with accessibility and usability guidelines and standards. The results showed that the platform had a good score regarding the automatic evaluation; however, when the heuristic and manual evaluations were performed, some accessibility and usability problems were discovered. Moreover, the user test results showed bad marks regarding efficiency, effectiveness, and satisfaction by the group of participants. As a conclusion, we highlight user interaction problems and propose seven recommendations focused on enhancing accessibility and usability of not only the evaluated e-commerce website, but also of other similar ones.

Abstract
Augmented reality (AR) technologies are reaching a maturity level where organizations in various business sectors can successfully incorporate them in their business activities. On its more developed spectrum, AR can deliver immersive multisensory environments in a 360 degrees virtual space. In what concerns the tourism sector, there are several possible applications of AR solutions with a significant prospect impact to organizations, tourists and, most importantly, territories. By acknowledging the issues associated with adopting disruptive information and communication technologies by activity sectors with less technology-awareness, in the current article we present a focused analysis to existing literature on the adoption of AR and, as a result of this, a conceptual model proposal aimed at explaining the adoption of AR by tourism related organizations with activity in low density territories.

Abstract
The blue economy potential is envisioned to increase the activity at the ocean worldwide in the coming years. To support these activities and the convergence to the Internet of Moving Things, Unmanned Surface Vehicles (USVs) are considered viable platforms to enable a large number of missions, including border surveillance and environmental monitoring. Typically, USVs use Wi-Fi for communicating with shore. However, in the literature, there is a lack of studies characterizing the shore-to-USV Wi-Fi link. This paper studies the influence of distance and USV orientation on the shore-to-USV link quality at the 2.4 GHz and 5.8 GHz Industrial, Scientific, and Medical (ISM) bands. The study is supported by experimental results, collected during sea trials. For the 2.4 GHz band, we conclude that neither the Two-Ray propagation model nor the Friis propagation model allow a good fit to the experimental measurements. On the other hand, for the 5 GHz band, the Friis propagation model fits the obtained experimental results. © 2018 IEEE.

Abstract
In this paper, an agent-based model is proposed to improve the electricity market efficiency by using different demand response programs (DRPs). In the proposed model, the strategic self-scheduling of each market player in the electricity market and consequent market interactions are considered by using a game theoretic model powered by a security constrained unit commitment. The tariffs of price-based DRPs and the amount of incentive in the incentive-based DRPs are optimized. Furthermore, a market power index and the operation cost are used to evaluate the market efficiency by using a multi-objective decision-making approach. The results show that different types of DRPs differently affect the oligopolistic behavior of market players, and the potential of market power in power systems can be mitigated by employing the proposed model for DRP optimization. Numerical studies reveal that applying combinational DRPs is more efficient when the regulatory body considers both economic and market power targets.

Abstract