Abstract
Industrial robots are a technology which is highly present in industry and can perform several tasks, namely machining activities. Different than CNC machines, which work with G-code and have available several software applications to generate the machine code, there is a lack of software for robotic arms, in addition to each application depending on its own language and software. This work studied a way to use different robotic arms for 3D part machining processes, to perform 3D objects reconstruction obtained through a low-cost 3D scanner. Dealing with the 3D reconstruction by integrating 3D acquisition and robotic milling with software available on the market, this paper presents a system that acquires and reconstructs a 3D object, in order to seek greater flexibility with lower initial investments and checking the applicability of robot arm in these tasks. For this, a 3D object is scanned and imported to a CAD/CAM software, to generate the machining toolpath, and a software application is used to convert the G-code into robot code. Several experiments were performed, using an ABB IRB 2600 robot arm, and the results of the machining process allowed to validate the G-code conversion and milling process using robotic arms, according to the proposed methodology.

Abstract
Occupational stress is a complex process affecting health and performance. Air Traffic Control is a complex and demanding profession. The current study demonstrates the concept of using a biomonitoring wearable platform (BWP), that combines self-report measures with biomarkers, to track stress among Air Traffic Controllers. A wearable ECG device was used to gather continuously medical-grade ECG data along with a mobile app for daily stress perception, symptoms and events annotation. A total of 256 hours of data from 32 routine work shifts and 5 days-off, from 5 ATCs was recorded with 35 tagged events using Heart Rate Variability metrics- AVNN, RMSSD, pNN50 and LF/HF were computed from ECG data and analyzed during a) shifts vs days off; b) events vs non-events and c) before and after working pauses. ATCs showed low levels of chronic stress using self-reports. Results showed that stress symptomatology slightly increase from the beginning to the end of the shift (Md=1 to Md=2; p<0.05). Statistical significant physiological changes were found between shifts and days off for AVNN and LF/HF (p<0.05), showing higher physiological activation during shifts. A significant reduction of physiological arousal was verified after working pauses, particularly for AVNN and LF/IIF (p<0.001). Self-reported data also suggests the same trend (p<0.005). Findings reinforced the discriminatory power of AVNN and LF/HF for short-term stress classification using HRV measurements. Results suggest that the rotating working system, with pause/resting periods included, effective acted as a recovery period.

Abstract
Virtual Reality (VR) has been showing potential in new and diverse areas, notably in education. However, there is a lack of studies in the Foreign Language Teaching and Learning field, particularly in listening comprehension. Therefore, this study investigated the effects of avatar animations and lip synchronization, and user interaction; features deemed relevant in this broader area. A sociodemographic, a quick CEFR-Common European Framework of Reference for Languages-15-minute English test, and questionnaire were used to evaluate the participants' Presence, Quality of Experience, Cybersickness and Knowledge Retention. Results show that, overall, the use of avatars with realistic animations and movements, and featuring lip synchronization have a positive influence on the users' sense of presence, knowledge retention and a more enjoyable overall quality of experience. The same can be said for the use of object interaction and navigation in the cultural representative environment, which had an overall positive impact.

Abstract
Electricity systems around the world are decarbonizing, driven by reductions in the cost of renewable energy and encouraged by supportive regulatory policy. Electricity market designs are increasingly being tested to ensure that the bulk power system can deliver reliable, cost-effective energy to all consumers.

Abstract
The complexities of Public Administration have gained the growing attention of scholars around the world, mainly due to the impacts of the reforms implemented under the doctrine of New Public Management (which aims to apply concepts and practices of private management in public management) on civil servants. The aim of this study is to find out how Portuguese citizens evaluate the Portuguese Public Administration under the aspects of bureaucracy, organisation of human resources, innovation, skills and attitudes of civil servants, its motivation and recognition; and to verify if there are differences of opinion between respondents working in public sector and respondents from other sectors. This study follows a quali-quantitative approach, and data were collected through an online survey in the period from June to December 2020. The survey was answered by 1119 citizens from all districts of Portugal. The main findings reveal a still high level of bureaucracy in the Portuguese Public Administration; weaknesses in the management of human resources, namely regarding the motivation and recognition of civil servants; and difficulties in the establishment of a meritocratic system of recruitment and performance evaluation of civil servants. Statistically significant evaluation differences (chi-square test and non-parametric Mann-Whitney U tests, involving five hypotheses) were found between the public sector and other sectors, except for the motivation variable.

Abstract
AbstractIn the pallet building problem, we aim at loading a given set of items into one or more pallets, by satisfying specific constraints and minimizing the number of pallets used. In this paper, we address a practical case of this problem that originates from a real-world robotized application, subject to some non-trivial operational constraints. In practice, items are grouped into families and must be packed into horizontal layers. To facilitate loading/unloading operations, items of the same type packed into the same layer should be contiguous and at least one of them should be visible from the outside. We present a formal mathematical description for layer and pallet creation subproblems and then we propose heuristic, metaheuristic, matheuristic algorithms to solve the overall problem. The performance of the algorithms is assessed through extensive computational tests on real-world instances.