2022
Authors
Oliveira, V; Pinto, T; Faia, R; Veiga, B; Soares, J; Romero, R; Vale, Z;
Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE, EPIA 2022
Abstract
Complex optimization problems are often associated to large search spaces and consequent prohibitive execution times in finding the optimal results. This is especially relevant when dealing with dynamic real problems, such as those in the field of power and energy systems. Solving this type of problems requires new models that are able to find near-optimal solutions in acceptable times, such as metaheuristic optimization algorithms. The performance of these algorithms is, however, hugely dependent on their correct tuning, including their configuration and parametrization. This is an arduous task, usually done through exhaustive experimentation. This paper contributes to overcome this challenge by proposing the application of sequential model algorithm configuration using Bayesian optimization with Gaussian process and Monte Carlo Markov Chain for the automatic configuration of a genetic algorithm. Results from the application of this model to an electricity market participation optimization problem show that the genetic algorithm automatic configuration enables identifying the ideal tuning of the model, reaching better results when compared to a manual configuration, in similar execution times.
2022
Authors
Baptista, D; Ferreira, PG; Rocha, M;
Publication
Abstract
2022
Authors
Ajel, S; Ribeiro, F; Ejbali, R; Saraiva, J;
Publication
ISDA (2)
Abstract
Although machine learning (ML) is a field that has been the subject of research for decades, a large number of applications with high computational power have recently emerged. Usually, we only focus on solving machine learning problems without considering how much energy has been consumed by the different frameworks used for such applications. This study aims to provide a comparison among four widely used frameworks such as Tensorflow, Keras, Pytorch, and Scikit-learn in terms of many aspects, including energy efficiency, memory usage, execution time, and accuracy. We monitor the performance of such frameworks using different well-known machine learning benchmark problems. Our results show interesting findings, such as slower and faster frameworks consuming less or more energy, higher or lower memory usage, etc. We show how to use our results to provide machine learning developers with information to decide which framework to use for their applications when energy efficiency is a concern.
2022
Authors
Lopes, CT; Ribeiro, C; Niccolucci, F; Villalón, MP; Freire, N;
Publication
SIGIR Forum
Abstract
2022
Authors
de Queiros, RAP; Pinto, M; Simões, A; Portela, CF;
Publication
Research Anthology on Game Design, Development, Usage, and Social Impact
Abstract
2022
Authors
Maia, JM; Viveiros, D; Amorim, VA; Marques, PVS;
Publication
OPTICS AND LASERS IN ENGINEERING
Abstract
This work addresses the fabrication of straight silica-core liquid-cladding suspended waveguides inside a microfluidic channel through fs-laser micromachining. These structures enable the reconfiguration of the waveguide's mode profile and enhance the evanescent interaction between light and analyte. Further, their geometry resembles a tapered optical fiber with the added advantage of being monolithically integrated within a microfluidic platform. The fabrication process includes an additional post-processing thermal treatment responsible for smoothening the waveguide surface and reshaping it into a circular cross-section. Suspended waveguides with a minimum core diameter of 3.8 mu m were fabricated. Their insertion losses can be tuned and are mainly affected by mode mismatch between the coupling and suspended waveguides. The transmission spectrum was studied and it was numerically confirmed that it consists of interference between the guided LP01 mode and uncoupled light and of modal interference between the LP01 and LP02 modes.
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