2024
Autores
Vérinaud, C; Héritier, CT; Kasper, M; Haffert, S; Snik, F; Doelman, D; Carlotti, A; Engler, B; Le Louarn, M; Correia, C; Tallon, M;
Publicação
ADAPTIVE OPTICS SYSTEMS IX
Abstract
Resolution and sensitivity of the wavefront sensor (WFS) are key requirements for eXtreme Adaptive Optics (XAO) applications. We present a new class of WFSs, the Bi-Orthogonal Foucault-knife-edge (Bi-O edge), that is directly inspired by the Foucault knife-edge test. The idea consists of using a beam-splitter producing two foci, each of which is sensed by an edge with an orthogonal direction to the other. We describe two implementation concepts. The first one, the tip-tilt modulated sharp Bi-O-edge, can be seen as a mild evolution of the Pyramid. The second one uses a smooth, gradual amplitude mask over a 'grey' zone on the edge (grey Bi-O edge). We analyze the increased gain in sensitivity and the super-resolution capability, we compare these properties to the Pyramid sensor and produce end-to-end simulations. An important advantage of the grey Bi-O edge is the static modulation which is well adapted for fast XAO systems. The grey edge consists of a rectangular zone on the edge of the same size as the modulation circle. We will discuss the manufacturability of loss-less grey Foucault-knife edges, and we develop a polarization-based technique for the Bi-O edge prototype for the ESO GHOST test bench.
2024
Autores
Sousa, J; Darabi, R; Sousa, A; Brueckner, F; Reis, LP; Reis, A;
Publicação
CoRR
Abstract
2024
Autores
Silvano, P; Amorim, E; Leal, A; Cantante, I; Jorge, A; Campos, R; Yu, N;
Publicação
Text2Story@ECIR
Abstract
Temporal reasoning has been the focus of several studies during the past years, both in linguistics and computational studies. Although advances on this topic are undeniable, there are still improvements to be made and new avenues to pursue. One relevant problem concerns the temporal ordering of the events, particularly asserting and representing how events are temporally related and how the story told in the narrative evolves. This paper aims to analyse the temporal structure of narratives present in news articles with the aid of different visualisations. To this end, we annotated a dataset of 119 news articles in European Portuguese following an annotation scheme that combines different parts of ISO 24617-Language Resource Management - Semantic Annotation Framework (SemAF). The temporal layer of this annotation scheme identifies the events and their main features, as well as the temporal links between the events. The annotation provided us with paramount information about the temporal characteristics of news at two levels: the story and the report levels. The visualisations that we propose facilitate the process of understanding how news are temporally organised, providing a more practical means to observe them.
2024
Autores
Ascençao, C; Teixeira, H; Gonçalves, J; Almeida, F;
Publicação
INFORMATION AND COMPUTER SECURITY
Abstract
PurposeSecurity in large-scale agile is a crucial aspect that should be carefully addressed to ensure the protection of sensitive data, systems and user privacy. This study aims to identify and characterize the security practices that can be applied in managing large-scale agile projects.Design/methodology/approachA qualitative study is carried out through 18 interviews with 6 software development companies based in Portugal. Professionals who play the roles of Product Owner, Scrum Master and Scrum Member were interviewed. A thematic analysis was applied to identify deductive and inductive security practices.FindingsThe findings identified a total of 15 security practices, of which 8 are deductive themes and 7 are inductive. Most common security practices in large-scale agile include penetration testing, sensitive data management, automated testing, threat modeling and the implementation of a DevSecOps approach.Originality/valueThe results of this study extend the knowledge about large-scale security practices and offer relevant practical contributions for organizations that are migrating to large-scale agile environments. By incorporating security practices at every stage of the agile development lifecycle and fostering a security-conscious culture, organizations can effectively address security challenges in large-scale agile environments.
2024
Autores
de Castro, GGR; Santos, TMB; Andrade, FAA; Lima, J; Haddad, DB; Honorio, LD; Pinto, MF;
Publicação
MACHINES
Abstract
This research presents a cooperation strategy for a heterogeneous group of robots that comprises two Unmanned Aerial Vehicles (UAVs) and one Unmanned Ground Vehicles (UGVs) to perform tasks in dynamic scenarios. This paper defines specific roles for the UAVs and UGV within the framework to address challenges like partially known terrains and dynamic obstacles. The UAVs are focused on aerial inspections and mapping, while UGV conducts ground-level inspections. In addition, the UAVs can return and land at the UGV base, in case of a low battery level, to perform hot swapping so as not to interrupt the inspection process. This research mainly emphasizes developing a robust Coverage Path Planning (CPP) algorithm that dynamically adapts paths to avoid collisions and ensure efficient coverage. The Wavefront algorithm was selected for the two-dimensional offline CPP. All robots must follow a predefined path generated by the offline CPP. The study also integrates advanced technologies like Neural Networks (NN) and Deep Reinforcement Learning (DRL) for adaptive path planning for both robots to enable real-time responses to dynamic obstacles. Extensive simulations using a Robot Operating System (ROS) and Gazebo platforms were conducted to validate the approach considering specific real-world situations, that is, an electrical substation, in order to demonstrate its functionality in addressing challenges in dynamic environments and advancing the field of autonomous robots.
2024
Autores
Loureiro, G; Dias, A; Almeida, J; Martins, A; Hong, SP; Silva, E;
Publicação
REMOTE SENSING
Abstract
The deep seabed is composed of heterogeneous ecosystems, containing diverse habitats for marine life. Consequently, understanding the geological and ecological characteristics of the seabed's features is a key step for many applications. The majority of approaches commonly use optical and acoustic sensors to address these tasks; however, each sensor has limitations associated with the underwater environment. This paper presents a survey of the main techniques and trends related to seabed characterization, highlighting approaches in three tasks: classification, detection, and segmentation. The bibliography is categorized into four approaches: statistics-based, classical machine learning, deep learning, and object-based image analysis. The differences between the techniques are presented, and the main challenges for deep sea research and potential directions of study are outlined.
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