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Publications

2024

Sustainable Development Goal 9 in a Cluster Perspective: a Case Study for Alto Minho Region

Authors
Abreu, M; Rodrigues, HS; Silva, A; Garcia, JE;

Publication
INTERNATIONAL CONFERENCE ON NUMERICAL ANALYSIS AND APPLIED MATHEMATICS 2022, ICNAAM-2022

Abstract
The United Nations has set Sustainable Development Goals (SDGs) to build a more sustainable future. The SDG analyzes progress to understand major implementation challlenges, define disparities across nations or regions, and propose priorities for action. It has 17 objectives and more than 200 indicators. Cluster analysis was used to categorize the 10 municipalities. It was carried out using IBM SPSS software, which calculated the Euclidean distance and put the investigated regions into clusters with the traits they shared the most in common.

2024

ML-assistant for human operators using alarm data to solve and classify faults in electrical grids

Authors
Campos, V; Klyagina, O; Andrade, JR; Bessa, RJ; Gouveia, C;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Nowadays, human operators at control centers analyze a large volume of alarm information during outage events and must act fast to restore the service. To assist operator decisions this work proposes novel machine learning-based functions aiming to: (a) classify the complexity of a fault occurrence (Occurrences Classifier) and its cause (Fault Cause Classifier) based on its alarm events; (b) provide fast insights to the operator on how to solve it (Data2Actions). The Occurrences Classifier takes alarm information of an occurrence and classifies it as a simpleor complexoccurrence, while the Fault Cause Classifier predicts the cause class of MV lines faults. The Data2Actions takes a sequence of alarm information from the occurrence and suggests a more adequate sequence of switching actions to isolate the fault section. These algorithms were tested on real data from a Distribution System Operator and showed: (a) an accuracy of 86% for the Data2Actions, (b) an accuracy of 68% for the Occurrences Classifier, and (c) an accuracy of 74% for the Fault Cause Classifier. It also proposes a new representation for SCADA event log data using graphs, which can help human operators identify infrequent alarm events or create new features to improve model performance.

2024

A Deep Learning Approach in RIS-based Indoor Localization

Authors
Aguiar, RA; Paulino, N; Pessoa, LM;

Publication
2024 JOINT EUROPEAN CONFERENCE ON NETWORKS AND COMMUNICATIONS & 6G SUMMIT, EUCNC/6G SUMMIT 2024

Abstract
In the domain of RIS-based indoor localization, our work introduces two distinct approaches to address real-world challenges. The first method is based on deep learning, employing a Long Short-Term Memory (LSTM) network. The second, a novel LSTM-PSO hybrid, strategically takes advantage of deep learning and optimization techniques. Our simulations encompass practical scenarios, including variations in RIS placement and the intricate dynamics of multipath effects, all in Non-Line-of-Sight conditions. Our methods can achieve very high reliability, obtaining centimeter-level accuracy for the 98th percentile (worst case) in a different set of conditions, including the presence of the multipath effect. Furthermore, our hybrid approach showcases remarkable resolution, achieving submillimeter-level accuracy in numerous scenarios.

2024

Exploring local chlorine generation through seawater electrolysis to Extend optical sensor lifespan in marine environments

Authors
Matos, T; Pinto, VC; Sousa, PJ; Martins, MS; Fernández, E; Goncalves, LM;

Publication
CHEMICAL ENGINEERING JOURNAL

Abstract
Biofouling in marine optical sensors poses a significant challenge as it can compromise data accuracy and instrument functionality. This study investigates the effectiveness of local chlorine generation by seawater electrolysis in mitigating biological fouling and extending the operational lifespan of optical oceanographic instruments. Eight similar turbidity probes integrated with a local chlorine generation system, along with a turbidity probe constructed from ABS and another from PLA with copper filament, were developed for testing in the marine environment. The chlorine probes were designed into two groups: four utilizing standard FTO glass and four featuring FTO glass coated with platinum nanoparticles. Each set of probes employed different excitation currents for chlorine generation. All probes underwent laboratory calibration using formazine before deployment in a coastal environment for 97 days. The findings demonstrate a correlation with higher electrical power leading to prolonged operation intervals free from biofouling interference. Additionally, probes coated with platinum nanoparticles demonstrate higher performance in comparison to those with standard FTO glass. The copper probe did not effectively shield the optical transducers from microfouling, although it effectively demonstrated its efficacy in protecting the structural housing of the device. Overall, this work offers a compelling in situ demonstration of local chlorine generation as a promising strategy for enhancing the performance and longevity of optical oceanographic instruments in marine environments.

2024

Optimising Wheelchair Path Planning

Authors
Ribeiro, B; Salgado, PA; Perdicoúlis, TPA; dos Santos, PL;

Publication
WIRELESS MOBILE COMMUNICATION AND HEALTHCARE, MOBIHEALTH 2023

Abstract
This article addresses the problem of wheelchair path planning. In particular, to minimize the length of the trajectory within an environment containing a variable number of obstacles. The positions and quantities of these obstacles are pre-determined. To tackle this challenge, we present a methodology that integrates optimisation techniques and heuristic algorithms to find trajectories both optimal and collision-free. The effectiveness of this methodology is illustrated through a practical example, demonstrating how it successfully generates a collision-free trajectory, even when a large number of obstacles is present in the workspace. In the future, we intend to continue investigating the same problem, taking into account energy consumption as well as time minimisation.

2024

Protection system planning in distribution networks with microgrids using a bi-level multi-objective and multi-criteria optimization technique

Authors
Reiz, C; Leite, JB; Gouveia, CS; Javadi, MS;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Microgrids are able to improve several features of power systems, such as energy efficiencies, operating costs and environmental impacts. Nevertheless, microgrids' protection must work congruently with power distribution protection to safely take all advantages. This research contributes to enable their protection by proposing a bilevel method to simultaneously solve the allocation and coordination problems, where the proposed scheme also includes local protections of distributed energy resources. The uncertainties associated with generation and loads are categorized by the k-means method, as well. The non-dominated sorting genetic algorithm II is employed in the upper-level task to solve the protection and control devices allocation problem with two opposing objectives. In the lower-level task, a genetic algorithm ensures their coordination. Protection devices include reclosers and fuses from the network, and directional relays for the point of common coupling of microgrids, while control devices consist of remote-controlled switches. In contrast to related works, local devices installed at the point of coupling of distributed generation units are considered as well, such as voltage-restrained overcurrent relays and frequency relays. The optimal solution for the decision-maker is achieved by utilizing the compromise programming technique. Results show the importance of solving the allocation and coordination problems simultaneously, achieving up to $25,000 cost savings compared to cases that solve these problems separately. The integrated strategy allows the network operator to select the optimum solution for the protective system and avoid corrective actions afterward. The results also show the viability of the islanding operation depending on the decision maker's criteria.

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