2023
Autores
Duque, JST; Ruiz-Armenteros, AM; Alvarez, GEA; Matiz, G; Sousa, JJ;
Publicação
REMOTE SENSING
Abstract
Bogota, the largest urban center and capital city of Colombia, is located within the Bogota savanna, which originated as a lake in the central part of the Colombian Eastern Cordillera. Over time, the lake transformed into a gently undulating plain with horizontally deposited sediments that formed around five million years ago. Over the last few decades, the region has undergone significant population growth and rapid urban development, largely driven by migration from rural areas. This development has substantially impacted the subsidence observed in the city, primarily due to the extraction of groundwater. A previous study by the Servicio Geologico Colombiano (SGC) utilized data from GNSS stations and synthetic aperture radar interferometry (InSAR) with TerraSAR-X SAR between 2011 and 2017 to identify a subsidence pattern in the central region of Bogota. The purpose of the study was to evaluate the risks and potential disasters associated with the subsidence phenomenon. Our study investigates both the subsidence in Bogota, previously studied, as well as the rural savanna area, which is currently undergoing significant residential and industrial development. We utilized multi-temporal InSAR (MT-InSAR) techniques with Sentinel-1 SAR images from 2014 to 2021. The analysis results indicate that the outer regions of the city display the most significant subsidence, extending from the center to the north. The subsidence velocities in these areas reach approximately 5-6 cm/year.
2023
Autores
Bechir M.H.; Martínez D.F.; Agüera A.L.;
Publicação
Proceedings of the 2nd International Conference on Water Energy Food and Sustainability Icowefs 2022
Abstract
Ensuring a sustainable transition process, whether at a global or local level, involves designing an energy mix appropriate to the user's needs. The aim is to identify the optimal future strategy that maximizes both socio-economic benefits and sustainability. To address these challenges, multiple modeling tools are now available to assess different scenarios before implementation. However, modeling tools are generally designed for economic optimization. This is the case with the Open-Source Energy Modeling System (OSeMOSYS) a CLEWs tool. This paper proposes an optimization methodology in terms of sustainability, introducing Life Cycle Assessment (LCA) as a global estimator. In particular, the effects of energy payback times (EPBT) on the selection of transition scenarios will be evaluated. To ensure the reproducibility of the study, we present an exercise that uses data for a fictitious country that shares features of both a developing and a developed country (Atlantis).
2023
Autores
Abreu, M; Kasaei, M; Reis, LP; Lau, N;
Publicação
ROBOCUP 2022
Abstract
FC Portugal, a team from the universities of Porto and Aveiro, won the main competition of the 2022 RoboCup 3D Simulation League, with 17 wins, 1 tie and no losses. During the course of the competition, the team scored 84 goals while conceding only 2. FC Portugal also won the 2022 RoboCup 3D Simulation League Technical Challenge, accumulating the maximum amount of points by ending first in its both events: the Free/Scientific Challenge, and the Fat Proxy Challenge. The team presented in this year's competition was rebuilt from the ground up since the last RoboCup. No previous code was used or adapted, with the exception of the 6D pose estimation algorithm, and the get-up behaviors, which were re-optimized. This paper describes the team's new architecture and development approach. Key strategy elements include team coordination, role management, formation, communication, skill management and path planning. New lower-level skills were based on a deterministic analytic model and a shallow neural network that learned residual dynamics through reinforcement learning. This process, together with an overlapped learning approach, improved seamless transitions, learning time, and the behavior in terms of efficiency and stability. In comparison with the previous team, the omnidirectional walk is more stable and went from 0.70m/s to 0.90 m/s, the long kick from 15m to 19m, and the new close-control dribble reaches up to 1.41 m/s.
2023
Autores
Marín, B; Vos, TEJ; Snoeck, M; Paiva, ACR; Fasolino, AR;
Publicação
Proceedings of the Research Projects Exhibition Papers Presented at the 35th International Conference on Advanced Information Systems Engineering (CAiSE 2023), Zaragoza, Spain, June 12-16, 2023.
Abstract
2023
Autores
Frazão, O; Robalinho, P; Vaz, A; Soares, L; Soares, B; Monteiro, C; Novais, S; Silva, S;
Publicação
EPJ Web of Conferences
Abstract
2023
Autores
Pereira, RR; Bono, J; Ascensao, JT; Aparício, D; Ribeiro, P; Bizarro, P;
Publicação
PROCEEDINGS OF THE 4TH ACM INTERNATIONAL CONFERENCE ON AI IN FINANCE, ICAIF 2023
Abstract
Machine learning methods to aid defence systems in detecting malicious activity typically rely on labelled data. In some domains, such labelled data is unavailable or incomplete. In practice this can lead to low detection rates and high false positive rates, which characterise for example anti-money laundering systems. In fact, it is estimated that 1.7-4 trillion euros are laundered annually and go undetected. We propose The GANfather, a method to generate samples with properties of malicious activity, without label requirements. We propose to reward the generation of malicious samples by introducing an extra objective to the typical Generative Adversarial Networks (GANs) loss. Ultimately, our goal is to enhance the detection of illicit activity using the discriminator network as a novel and robust defence system. Optionally, we may encourage the generator to bypass pre-existing detection systems. This setup then reveals defensive weaknesses for the discriminator to correct. We evaluate our method in two real-world use cases, money laundering and recommendation systems. In the former, our method moves cumulative amounts close to 350 thousand dollars through a network of accounts without being detected by an existing system. In the latter, we recommend the target item to a broad user base with as few as 30 synthetic attackers. In both cases, we train a new defence system to capture the synthetic attacks.
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