2024
Authors
Cameira, C; Maia, M; Marques, PVS;
Publication
EPJ Web of Conferences
Abstract
This study reports the fabrication of three-dimensional microfluidic channels in fused silica, using femtosecond laser micromachining, to achieve two-dimensional hydrodynamic flow focusing in either the horizontal or the vertical directions. Spatial focusing of 3 µm polystyrene particles was successfully demonstrated, showing the ability of the fabricated devices to confine microparticles within a 6 µm layer over a channel width of 420 µm and within a 5 µm layer over a channel height of 260 µm. Integration of laser-direct written optical waveguides inside a microfluidic chip and orthogonal to the channel also enabled the implementation of a dual-beam optical trap, with trapping of polystyrene microparticles using a 1550 nm beam being demonstrated. © The Authors.
2024
Authors
Gonçalves, T; Almada Lobo, B;
Publication
Journal of Revenue and Pricing Management
Abstract
Traditional revenue management systems are built under the assumption of independent demand per fare. The fare adjustment theory is a methodology to adjust fares that allows for the continued use of optimization algorithms and seat inventory control methods, even with the shift toward dependent demand. Since accurate demand forecasts are a key input to this methodology, it is reasonable to assume that for a scenario with uncertainties it may deliver suboptimal performance. Particularly, during and after COVID-19, airlines faced striking challenges in demand forecasting. This study demonstrates, firstly, the theoretical dominance of the fare adjustment theory under perfect conditions. Secondly, it lacks robustness to forecast errors. A Monte Carlo simulation replicating a revenue management system under mild assumptions indicates that a forecast error of ±20% can potentially prompt a necessity to adjust the margin employed in the fare adjustment theory by -10%. Moreover, a tree-based machine learning model highlights the forecast error as the predominant factor, with bias playing an even more pivotal role than variance. An out-of-sample study indicates that the predictive model steadily outperforms the fare adjustment theory. © The Author(s), under exclusive licence to Springer Nature Limited 2024.
2024
Authors
Moreira, C; Costa, C; Santos, AS; Madureira, AM; Barbosa, M;
Publication
FLEXIBLE AUTOMATION AND INTELLIGENT MANUFACTURING: ESTABLISHING BRIDGES FOR MORE SUSTAINABLE MANUFACTURING SYSTEMS, FAIM 2023, VOL 2
Abstract
Nowadays, decision making is one of the most important and influential aspects of everyday life, and the application of metaheuristics and heuristics facilitates the process. Thus, this paper presents a performance analysis of the combination of constructive heuristics used to generate initial solutions for metaheuristics applied to scheduling problems. Namely, Nawaz, Enscore, and Ham Heuristic (NEH), Palmer Heuristic and Campbell, Dudek, and Smith Heuristic (CDS) with Cuckoo Search, Firefly Algorithm and Simulated Annealing. The aim is to compare the performance of these combinations to analyse the efficiency, effectiveness and robustness of each. All combinations were analysed in an in-depth computational study and then subjected to a statistical study to support an accurate analysis of the results. The results of the analysis show that the Firefly Algorithm associated with NEH, despite having a high runtime, performs better than the other combinations. However, the best effectiveness-efficiency ratio corresponds to SA-Palmer and SA-CDS.
2024
Authors
Garcia, PJV; Morujdoa, N; Leftley, J; Matter, A; Percheron, I;
Publication
OPTICAL AND INFRARED INTERFEROMETRY AND IMAGING IX
Abstract
The delivery of curated data from astronomical instruments has become a reality in many observatories. The European Southern Observatory (ESO) delivers science-ready data products for various instruments, ranging from imagers to integral field spectrographs. In the case of infrared long-baseline interferometry, scientists generally make their curated data available through the Optical Interferometry Database (OiDB) once it is published. We report on a project to create a curated data stream for the GRAVITY instrument at the Very Large Telescope Interferometer. We aim to transform the publicly available raw data in the ESO science archive into science-ready curated data.
2024
Authors
Karácsony T.; Fearns N.; Vollmar C.; Birk D.; Rémi J.; Noachtar S.; Silva Cunha J.P.;
Publication
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
Abstract
Epileptic seizures are clearly characterized by their displayed behavior, the semiology, which is used in diagnosis and classification as a base for therapy. This article presents a novel 4K 3D video recording and reviewing system for epilepsy monitoring, introducing a novel perspective and allowing continuous recording and review of 3D videos in the epilepsy monitoring unit (EMU), providing significantly more detail than the current clinical systems, which can lead to the recognition of more Movements of Interest (MOIs) and may reduce inter-rater variability. To put the system to an initial test in clinical practice the article presents three real-world examples of subtle MOIs, that could only be appreciated on the 4K-video, but not on the VGA-video, recorded as part of the clinical routine. In conclusion, a 4K-RGB recording, 3D cropping, and 3D video playing system was developed, implemented, and tested for realworld clinical scenarios, considering the specific requirements of clinical monitoring in EMUs. The new data acquisition setup can support clinical diagnosis, which may lead to new insights in the field of epilepsy and the development of AI approaches in the future.
2024
Authors
Correia, Miguel; Marques, Catarina; Trigo, Luís; Quirino, Carolina; Silva, Henrique; Rocha, Tiago; Coelho, António;
Publication
Abstract
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