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Publicações

2023

A study on the Motivation of Computer Science Students to Learn Programming

Autores
Silva, L; Gomes, A; Borges, AR; Vasconcelos, V; Mendes, AJ;

Publicação
25th International Symposium on Computers in Education, SIIE 2023

Abstract
This work focuses on the motivation levels of introductory programming students and their relationship with their learning performance. The study involved students enrolled in the Introduction to Programming (IP) course included in two slightly different Informatics Engineering degrees at the same institution. The motivation section of the Motivated Strategies for Learning Questionnaire (MSLQ) instrument includes several scales and subscales used to analyse different motivational factors.Four research questions guided the study. The first is comparing the results of the two groups of students. The second considered the student's previous programming experience and tried correlating it with motivational factors. The third is similar but separates students following IP for the first time and those who had failed it in previous years. Finally, the fourth research question examined the influence of motivational factors on students' learning performance measured by their final grades.This paper provides a detailed study description and presents and discusses its results. © 2023 IEEE.

2023

Planning and Financing Strategy for Clustered Multi-Carrier Microgrids

Autores
Azimian, M; Habibifar, R; Amir, V; Shirazi, E; Javadi, MS; Nezhad, AE; Mohseni, S;

Publicação
IEEE ACCESS

Abstract
This paper discusses the optimal deployment of a cluster consisting of connected AC-coupled, low voltage (48 V) multi-carrier microgrids within an integrated framework. The utilization of this integrated framework proves to be an effective approach for enhancing the reliability, resiliency, and operational quality of the clustered multi-carrier microgrids. Furthermore, it enables improved utilization of distributed energy resources in both grid-connected and stand-alone scenarios. In order to address local objectives, this paper presents a hybrid approach to determine the optimal integration and size of distributed energy resources in autonomous multi-carrier microgrids. Additionally, the proposed model identifies the ideal demand response intensity for each multi-carrier microgrid, which can result in energy savings and financial profits by modifying energy demands during peak hours. The primary objective is to minimize the development cost of clustered multi-carrier microgrids while ensuring a desired level of local reliability and online reserve. To address the planning problem of the proposed integrated parallel multi-carrier microgrid network, a mixed-integer programming model is formulated. Numerical results obtained from a three-microgrid system demonstrate the effectiveness of the proposed integrated planning model, validating the economic viability of the expansion project from various financial perspectives. Finally, a practical financing strategy is proposed to facilitate the successful implementation and deployment of parallel multi-carrier microgrids, thereby contributing to the achievement of sustainable development goals. The study examines the role of governments in facilitating capital investments for clustered multi-carrier microgrid projects, aligning with sustainable development goals. It proposes a feasible financing strategy through settled billing tax rates ranging from 4% to 26% for multi-carrier microgrid customers over ten years. This strategy can assist policymakers in formulating supportive policy programs to effectively implement and promote multi-carrier microgrids in diverse premises.

2023

Paracetamol concentration-sensing scheme based on a linear cavity fiber laser configuration

Autores
Soares, L; Perez Herrera, RA; Novais, S; Ferreira, A; Fraza, O; Silva, S;

Publicação
OPTICAL FIBER TECHNOLOGY

Abstract
A paracetamol concentration-sensing scheme based on a linear cavity fiber laser configuration is demonstrated experimentally. The laser cavity has a fiber sensor at one end, that allows refractive index measurements. The refractometer consists of a cleaved fiber tip combined with an FBG functioning as a reflecting mirror. The combination of a fiber loop mirror at the other end allows to reflect all the light from the FBG and refractometer, forming a linear cavity. By measuring the intensity variation of the Fresnel reflection at the fiber-to-liquid interface, the measured concentration is linear and have a concentration sensitivity of [( - 8.74 & PLUSMN; 0.34) x 10-5 ] & mu;W/(g/kg), over a range of 52.61 to 219.25 g/kg, and with a resolution of 2.77 g/kg. The results obtained present high stability and prove the potential of the fiber laser system to performed realtime measurements of concentration, in a non-invasive way.

2023

Automatic Test-Based Assessment of Assembly Programs

Autores
Tavares, L; Lima, B; Araújo, A;

Publicação
Proceedings of the 18th International Conference on Software Technologies

Abstract

2023

Firefly and Cuckoo Search Algorithm for Scheduling Problems: A Performance Analysis

Autores
Moreira, C; Costa, C; Santos, AS; Bastos, JA; Varela, LR; Brito, MF;

Publicação
Lecture Notes in Mechanical Engineering

Abstract
Meta-heuristics are some of the best-known techniques to approach hard optimization problems, however, there are still questions about what makes some meta-heuristics better than others in a specific problem. This paper presents an analysis of the Firefly and Cuckoo Search Algorithm, such as others meta-heuristics. In order to assess the performance of the Firefly Algorithm and the Cuckoo Search Algorithm, they were compared with other well-known optimization techniques, such as Simulated Annealing and Local Search. Both meta-heuristics analysed in an in-depth computational study, reaching the conclusion that both techniques could be useful in Scheduling Problems and lead to satisfactory solutions quickly and efficiently. Moreover, the results of the analysis show that the Firefly Algorithm, despite having a high runtime, performs better than the other techniques. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

2023

Direct discovery of the inner exoplanet in the HD206893 system Evidence for deuterium burning in a planetary-mass companion

Autores
Hinkley, S; Lacour, S; Marleau, GD; Lagrange, AM; Wang, JJ; Kammerer, J; Cumming, A; Nowak, M; Rodet, L; Stolker, T; Balmer, WO; Ray, S; Bonnefoy, M; Molliere, P; Lazzoni, C; Kennedy, G; Mordasini, C; Abuter, R; Aigrain, S; Amorim, A; Asensio-Torres, R; Babusiaux, C; Benisty, M; Berger, JP; Beust, H; Blunt, S; Boccaletti, A; Bohn, A; Bonnet, H; Bourdarot, G; Brandner, W; Cantalloube, F; Caselli, P; Charnay, B; Chauvin, G; Chomez, A; Choquet, E; Christiaens, V; Clenet, Y; du Foresto, VC; Cridland, A; Delorme, P; Dembet, R; Drescher, A; Duvert, G; Eckart, A; Eisenhauer, F; Feuchtgruber, H; Galland, F; Garcia, P; Lopez, RG; Gardner, T; Gendron, E; Genzel, R; Gillessen, S; Girard, JH; Grandjean, A; Haubois, X; Heissel, G; Henning, T; Hippler, S; Horrobin, M; Houlle, M; Hubert, Z; Jocou, L; Keppler, M; Kervella, P; Kreidberg, L; Lapeyrere, V; Le Bouquin, JB; Lena, P; Lutz, D; Maire, AL; Mang, F; Merand, A; Meunier, N; Monnier, JD; Mouillet, D; Nasedkin, E; Ott, T; Otten, GPPL; Paladini, C; Paumard, T; Perraut, K; Perrin, G; Philipot, F; Pfuhl, O; Pourre, N; Pueyo, L; Rameau, J; Rickman, E; Rubini, P; Rustamkulov, Z; Samland, M; Shangguan, J; Shimizu, T; Sing, D; Straubmeier, C; Sturm, E; Tacconi, LJ; van Dishoeck, EF; Vigan, A; Vincent, F; Ward-Duong, K; Widmann, F; Wieprecht, E; Wiezorrek, E; Woillez, J; Yazici, S; Young, A; Zicher, N;

Publicação
ASTRONOMY & ASTROPHYSICS

Abstract
Aims. HD206893 is a nearby debris disk star that hosts a previously identified brown dwarf companion with an orbital separation of similar to 10 au. Long-term precise radial velocity (RV) monitoring, as well as anomalies in the system proper motion, has suggested the presence of an additional, inner companion in the system. Methods. Using information from ongoing precision RV measurements with the HARPS spectrograph, as well as Gaia host star astrometry, we have undertaken a multi-epoch search for the purported additional planet using the VLTI/GRAVITY instrument. Results. We report a high-significance detection over three epochs of the companion HD206893c, which shows clear evidence for Keplerian orbital motion. Our astrometry with similar to 50-100 mu arcsec precision a fforded by GRAVITY allows us to derive a dynamical mass of 12.7(+1:2) (-1:0) M-Jup and an orbital separation of 3.53(+0:08) (-0:06) au for HD206893c. Our fits to the orbits of both companions in the system use both Gaia astrometry and RVs to also provide a precise dynamical estimate of the previously uncertain mass of the B component, and therefore allow us to derive an age of 155 +/- 15 Myr for the system. We find that theoretical atmospheric and evolutionary models that incorporate deuterium burning for HD206893c, parameterized by cloudy atmosphere models as well as a '' hybrid sequence '' (encompassing a transition from cloudy to cloud-free), provide a good simultaneous fit to the luminosity of both HD206893B and c. Thus, accounting for both deuterium burning and clouds is crucial to understanding the luminosity evolution of HD206893c. Conclusions. In addition to using long-term RV information, this e ffort is an early example of a direct imaging discovery of a bona fide exoplanet that was guided in part by Gaia astrometry. Utilizing Gaia astrometry is expected to be one of the primary techniques going forward for identifying and characterizing additional directly imaged planets. In addition, HD206893c is an example of an object narrowly straddling the deuteriumburning limit but unambiguously undergoing deuterium burning. Additional discoveries like this may therefore help clarify the discrimination between a brown dwarf and an extrasolar planet. Lastly, this discovery is another example of the power of optical interferometry to directly detect and characterize extrasolar planets where they form, at ice-line orbital separations of 2 4 au.

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