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Publications

2024

Adaptation and Validation of the Simulator Sickness Questionnaire to Portuguese (SSQp) Based on Immersive Virtual Reality Exposure

Authors
Gonçalves, G; Melo, M; Serôdio, C; Silva, R; Bessa, M;

Publication
IEEE ACCESS

Abstract
Cybersickness refers to the negative symptoms caused by exposure to a Virtual Reality (VR) experience. The literature is consensual that cybersickness is a key factor in an experience, as the non-existence of cybersickness provides an optimal virtual experience. Thus, it is of utmost importance to evaluate cybersickness when assessing VR applications to understand the impact of this factor on the user experience and, ultimately, on the VR application viability. However, there is a lack of Portuguese instruments to evaluate this variable. To tackle this, this aimed to translate and validate the Simulator Sickness Questionnaire (SSQ) to Portuguese so it can be used with the Portuguese population and maintain its psychometric properties. The new instrument was validated using a sample of 603 Portuguese subjects aged between 16 and 79. Based on the observed results, the obtained theoretical model shows that the Portuguese version of the SSQ is valid for properly evaluating cybersickness in VR experiences with Portuguese samples.

2024

PPG-Based Real-Time Blood Pressure Monitoring using Reflective Pulse Transit Time: Rest vs. Exercise Evaluation

Authors
Aslani, R; Dias, D; Cunha, JPS;

Publication
2024 IEEE 22ND MEDITERRANEAN ELECTROTECHNICAL CONFERENCE, MELECON 2024

Abstract
Direct blood pressure (BP) measurements require cuff compression, which not only is time-consuming but also inconvenient for frequent monitoring. This study addresses the challenge of continuous BP estimation (both Systolic (SBP) and Diastolic (DBP)) during exercise in a cuff-less manner, utilizing photoplethysmography (PPG) signals acquired by low-cost wearables. Leveraging Reflective Pulse-wave Transit Time (R-PTT), state-of-the-art algorithms were put to the test in two datasets (total subjects = 18). DATASET1 contains PPG signal and BP measurements of subjects in resting state, while DATASET2 comprises data of subjects in resting state and during exercise. The results reveal competitive performance, with Mean Absolute Error (MAE) of the estimation algorithm for DATASET1 being SBP=7.9 mmHg and DBP=5.2 mmHg and SBP=14.4 mmHg and DBP=7.7 mmHg for DATASET2. DATASET1 consistently outperforms DATASET2, affirming the algorithm's efficacy during resting states and that estimation during physical activity introduces challenges, requiring further refinement and research for real-world applications. In conclusion, this research unveils a viable solution for continuous cuff-less BP monitoring, while emphasizing the need for refinement and validation to enhance its clinical applicability and accessibility.

2024

A Flexible-Granularity Task Graph Representation and Its Generation from C Applications (WIP)

Authors
Santos, T; Bispo, J; Cardoso, JMP;

Publication
PROCEEDINGS OF THE 25TH ACM SIGPLAN/SIGBED INTERNATIONAL CONFERENCE ON LANGUAGES, COMPILERS, AND TOOLS FOR EMBEDDED SYSTEMS, LCTES 2024

Abstract
Modern hardware accelerators, such as FPGAs, allow offloading large regions of C/C++ code in order to improve the execution time and/or the energy consumption of software applications. An outstanding challenge with this approach, however, is solving the Hardware/Software (Hw/Sw) partitioning problem. Given the increasing complexity of both the accelerators and the potential code regions, one needs to adopt a holistic approach when selecting an offloading region by exploring the interplay between communication costs, data usage patterns, and target-specific optimizations. To this end, we propose representing a C application as an extended task graph (ETG) with flexible granularity, which can be manipulated through the merging and splitting of tasks. This approach involves generating a task graph overlay on the program's Abstract Syntax Tree (AST) that maps tasks to functions and the flexible granularity operations onto inlining/outlining operations. This maintains the integrity and readability of the original source code, which is paramount for targeting different accelerators and enabling code optimizations, while allowing the offloading of code regions of arbitrary complexity based on the data patterns of their tasks. To evaluate the ETG representation and its compiler, we use the latter to generate ETGs for the programs in Rosetta and MachSuite benchmark suites, and extract several metrics regarding data communication, task-level parallelism, and dataflow patterns between pairs of tasks. These metrics provide important information that can be used by Hw/Sw partitioning methods.

2024

Inclusivity Play

Authors
Giesteira, B; Peçaibes, V; Cardoso, P; Maior, GV; Quaresma, I;

Publication
Advances in Educational Marketing, Administration, and Leadership - Exploring Educational Equity at the Intersection of Policy and Practice

Abstract
“Portal for sharing teaching experience in the inclusion of diversity” corresponds to axis 4.2. of the project Skills for the Next Generation of the University of Porto by supporting the development of innovative and inclusive pedagogical resources, sharing information, experience about inclusivity and ludic tools to cope with the individual differences integrated with the university's information system. This project is intended to contribute to the achievement of the inclusive priorities defined at the European level through a web platform capable of deliverable informative content and gamified resources (serious and critical games) to give adequate support for the university academy, not only to cope with the difference but to take advantage of it, dealing with human differences and specificities as an asset to the community, unlike shortcomings.

2024

Combining Gaia and GRAVITY: Characterising five new directly detected substellar companions

Authors
Winterhalder, TO; Lacour, S; Mérand, A; Kammerer, J; Maire, A; Stolker, T; Pourré, N; Babusiaux, C; Glindemann, A; Abuter, R; Amorim, A; Asensio Torres, R; Balmer, WO; Benisty, M; Berger, J; Beust, H; Blunt, S; Boccaletti, A; Bonnefoy, M; Bonnet, H; Bordoni, MS; Bourdarot, G; Brandner, W; Cantalloube, F; Caselli, P; Charnay, B; Chauvin, G; Chavez, A; Choquet, E; Christiaens, V; Clénet, Y; du Foresto, V; Cridland, A; Davies, R; Dembet, R; Dexter, J; Drescher, A; Duvert, G; Eckart, A; Eisenhauer, F; Schreiber, NM; Garcia, P; Lopez, R; Gardner, T; Gendron, E; Genzel, R; Gillessen, S; Girard, JH; Grant, S; Haubois, X; Heißel, G; Henning, TH; Hinkley, S; Hippler, S; Houllé, M; Hubert, Z; Jocou, L; Keppler, M; Kervella, P; Kreidberg, L; Kurtovic, NT; Lagrange, A; Lapeyrère, V; Le Bouquin, J; Lutz, D; Mang, F; Marleau, G; Mollière, P; Monnier, JD; Mordasini, C; Mouillet, D; Nasedkin, E; Nowak, M; Ott, T; Otten, GPPL; Paladini, C; Paumard, T; Perraut, K; Perrin, G; Pfuhl, O; Pueyo, L; Ribeiro, DC; Rickman, E; Rustamkulov, Z; Shangguan, J; Shimizu, T; Sing, D; Stadler, J; Straub, O; Straubmeier, C; Sturm, E; Tacconi, LJ; van Dishoeck, EF; Vigan, A; Vincent, F; von Fellenberg, SD; Wang, JJ; Widmann, F; Woillez, J; Yazici, S;

Publication
Astronomy and Astrophysics

Abstract
Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how the combination of data obtained by Gaia and GRAVITY can help enlarge the sample of substellar companions with measured dynamical masses. We show how the Non-Single-Star (NSS) two-body orbit catalogue contained in Gaia DR3 can be used to inform high-angular-resolution follow-up observations with GRAVITY. Applying the method presented in this work to eight Gaia candidate systems, we detect all eight predicted companions, seven of which were previously unknown and five are of a substellar nature. Among the sample is Gaia DR3 2728129004119806464 B, which – detected at an angular separation of (34.01 ± 0.15) mas from the host – is the closest substellar companion ever imaged. In combination with the system’s distance and the orbital elements, this translates to a semi-major axis of (0.938 ± 0.023) AU. WT 766 B, detected at a greater angular separation, was confirmed to be on an orbit exhibiting an even smaller semi-major axis of (0.676 ± 0.008) AU. The GRAVITY data were then used to break the host-companion mass degeneracy inherent to the Gaia NSS orbit solutions as well as to constrain the orbital solutions of the respective target systems. Knowledge of the companion masses enabled us to further characterise them in terms of their ages, effective temperatures, and radii via the application of evolutionary models. The inferred ages exhibit a distinct bias towards values younger than what is to be expected based on the literature. The results serve as an independent validation of the orbital solutions published in the NSS two-body orbit catalogue and show that the combination of astrometric survey missions and high-angular-resolution direct imaging holds great promise for efficiently increasing the sample of directly imaged companions in the future, especially in the light of Gaia’s upcoming DR4 and the advent of GRAVITY+. © The Authors 2024.

2024

Arduino in Automatic Control Education: RC Circuit Step Response Analysis

Authors
dos Santos, PL; Perdicoúlis, TPA;

Publication
IFAC PAPERSONLINE

Abstract
The step response of first-order systems is vital in control systems and electronics. Understanding this behaviour is key but often challenging. This article uses Arduino with PWM to teach the step response in RC circuits, since Arduino enables real-time data acquisition and visualisation, connecting theory to practice. The research seeks to illustrate the step response of an RC circuit using Arduino, deepen knowledge of first-order systems, and offer a technique for collecting experimental data. All of this, since combining practical experiments with theoretical concepts boosts student involvement and understanding of dynamic systems. The work includes theoretical foundations, experimental procedures, and a brief discussion on the educational value of these activities.

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