Abstract
There is an increasing demand for robotic manipulators to perform more complex and versatile tasks. In order to fulfill this need, expeditious calibration and estimation techniques are required as a first step for the correct usage of the manipulator. This article aims at finding a subset of these algorithms that could be used in a generic manipulator and should allow for its prompt use. Two models for the representation of the pose of the manipulator are described and used in the state estimation problem. The results of the implementation are tested, and some performance metrics are obtained.

Abstract
To perform autonomous tasks, robots in real-world environments must be able to navigate in dynamic and unknown spaces. To do so, they must recognize previously seen places to compensate for accumulated positional deviations. This task requires effective identification of recovered landmarks to produce a consistent map, and the use of binary descriptors is increasing, especially because of their compact representation. The visual Bag-of-Words (BoW) algorithm is one of the most commonly used techniques to perform appearance-based loop closure detection quickly and robustly. Therefore, this paper presents a behavioral evaluation of a conventional BoW scheme based on Oriented FAST and Rotated BRIEF (ORB) features for image similarity detection in challenging scenarios. For each scenario, full-indexing vocabularies are created to model the operating environment and evaluate the performance for recognizing previously seen places similar to online approaches. Experiments were conducted on multiple public datasets containing scene changes, perceptual aliasing conditions, or dynamic elements. The Bag of Binary Words technique shows a good balance to deal with such severe conditions at a low computational cost.

Abstract
The digital contact tracing applications are one of the many initiatives to fight the COVID-19 virus. Some of these Apps use the Exposure Notification (EN) system available on Google and Apple's operating systems. However, EN-based contact tracing Apps depend on the availability of Bluetooth interfaces to exchange proximity identifiers, which, if compromised, directly impact their effectiveness. This paper discloses and details the Advertising Overflow attack, a novel internal Denial of Service (DoS) attack targeting the EN system on Android devices. The attack is performed by a malicious App that occupies all the Bluetooth advertising slots in an Android device, effectively blocking any advertising attempt of EN or other Apps. The impact of the disclosed attack and other previously disclosed DoS-based attacks, namely Battery Exhaustion and Storage Drain, were tested using two target smartphones and other six smartphones as attackers. The results show that the Battery Exhaustion attack imposes a battery discharge rate 1.95 times higher than in the normal operation scenario. Regarding the Storage Drain, the storage usage increased more than 30 times when compared to the normal operation scenario results. The results of the novel attack reveal that a malicious App can prevent any other App to place their Bluetooth advertisements, for any chosen time period, thus canceling the operation of the EN system and compromising the efficiency of any COVID contact tracing App using this system.

Abstract
Considering the nature, extent, and purpose of food processing, this study aims to identify dietary patterns (DPs) and their associations with sociodemographic factors and diet quality in Portuguese children and adolescents. Cross-sectional data were obtained from the National Food, Nutrition and Physical Activity Survey (2015-2016) of the Portuguese population. Dietary intake was obtained from two non-consecutive days and food items were classified according to the NOVA system. The proportion (in grams) of foods in the total daily diet was considered to identify DPs by latent class analysis, with age and sex as concomitant variables. Associations of DPs with sociodemographic characteristics were assessed using multinomial logistic regression. Linear regressions adjusted by sociodemographic characteristics tested associations of DPs with diet quality. DPs identified were: "Unhealthy " (higher sugar-sweetened beverages, industrial breads, and sausages intake), "Traditional " (higher vegetables, fish, olive oil, breads, ultra-processed yogurts, and sausages intake), and "Dairy " (higher intake of milk, yogurt, and milk-based beverages). "Unhealthy " was associated with older ages and lower intake of dietary fibre and vitamins and the highest free sugars and ultra-processed foods (UPF), although all DPs presented significant consumption of UPF. These findings should be considered for the design of food-based interventions and school-feeding policies in Portugal.

Abstract
Future Secondary Substation (SS) design requires a more integrated approach, from the building envelope design, electromechanically equipments to the advanced monitoring and control, taking into account new technical, environmental and economic requirements. The main objective of the project is to develop an integrated solution for the SSS, considering innovative solutions for the building envelope and thermal behavior, power transformer and switching equipment as well as monitoring, protection and control system. This paper presents the specification of future SS developed in Portuguese project NEXTSTEP - Next Distribution SubsTation ImprovEd Platform and describes its mains innovative solution and advanced control functionalities.

Abstract
Os Cadernos de Investigação do Mestrado em Negócio Eletrónico publicam anualmente os artigos científicos desenvolvidos pelos alunos, em colaboração com os seus orientadores de Dissertação/Projeto/Estágio, no âmbito da unidade curricular Metodologias de Investigação e Comunicação Científica, incluindo os alunos da turma de mobilidade Erasmus.