State estimation of over-sensored systems applied to a low-cost robotic manipulator

There is an increasing demand for robotic manipulators to perform more complex and versatile tasks. In order to fulfill this need, expeditious calibration and estimation techniques are required as a first step for the correct usage of the manipulator. This article aims at finding a subset of these algorithms that could be used in a generic manipulator and should allow for its prompt use. Two models for the representation of the pose of the manipulator are described and used in the state estimation problem. The results of the implementation are tested, and some performance metrics are obtained.info:eu-repo/semantics/publishedVersio

Fabrication of AZ4562 refractive microlenses array for light enhancement on optical microsystems

This paper presents the fabrication of an array of high aspect ratio photoresist based refractive microlenses (ML) using photolithography and thermal reflow. First, and in order to evaluate and predict the MLs optical properties and physical dimensions, finite element analysis was done. These simulations helped to design the super high resolution chrome on soda lime glass photomask as well as the parameters for the lithographic processes. Then, an array of high aspect ratio structures (length 4.9 mm, width 30 μm and 5 μm spacing between adjacent structures) with 5 μm thickness were fabricated. The thermal reflow technique (using a hotplate) was applied and an array of MLs measuring 5 and 32 μm at the vertex and radius, respectively, was achieved. When the photoresist (PR) is heated up above its glass transition temperature, it melts and the surface tension effect causes the fabricated microstructure to obtain the spherical lens profile. The hotplate thermal reflow is simple and easy to control, thus permitting the fabrication of smooth and homogeneous surfaces essential for good quality refractive microlenses.This work was supported by the Portuguese Foundation for Science and Technology under the projects FCT/PTDC/EEA-ELC/109936/2009 and FCT/MITPT/ EDAM-SI/0025/2008

Editorial: Glial plasticity in depression

info:eu-repo/semantics/publishedVersio

Sistema electrónico de controlo de temperatura da água para aplicações domésticas

Este artigo descreve um sistema que permite controlar a temperatura e regular o caudal das águas sanitárias num ambiente doméstico. O sistema tem como limite sete saídas independentes de caudal, substituindo as tradicionais torneiras mecânicas e manuais. A arquitectura do sistema está dividida em dois tipos de blocos: a interface com o utilizador (IU) e o bloco de controlo e regulação (CR). A IU é composta por um mostrador e por um teclado que permitem a interacção do utilizador com o sistema. O bloco de CR é constituído por um circuito electrónico que gere os módulos da IU e o sistema electromecânico. No controlo de temperatura é usado um controlador PID digital. A regulação do caudal de cada saída é efectuada de forma independente.info:eu-repo/semantics/publishedVersio

Functionality of the paracoccidioides mating α-pheromone-receptor system

Recent evidence suggests that Paracoccidioides species have the potential to undergo sexual reproduction, although no sexual cycle has been identified either in nature or under laboratory conditions. In the present work we detected low expression levels of the heterothallic MAT loci genes MAT1-1 and MAT1-2, the a-pheromone (PBa) gene, and the a- and apheromone receptor (PREB and PREA) genes in yeast and mycelia forms of several Paracoccidioides isolates. None of the genes were expressed in a mating type dependent manner. Stimulation of P. brasiliensis MAT1-2 strains with the synthetic a pheromone peptide failed to elicit transcriptional activation of MAT1-2, PREB or STE12, suggesting that the strains tested are insensitive to a-pheromone. In order to further evaluate the biological functionality of the pair a-pheromone and its receptor, we took advantage of the heterologous expression of these Paracoccidioides genes in the corresponding S. cerevisiae null mutants. We show that S. cerevisiae strains heterologously expressing PREB respond to Pba pheromone either isolated from Paracoccidioides culture supernatants or in its synthetic form, both by shmoo formation and by growth and cell cycle arrests. This allowed us to conclude that Paracoccidioides species secrete an active a-pheromone into the culture medium that is able to activate its cognate receptor. Moreover, expression of PREB or PBa in the corresponding null mutants of S. cerevisiae restored mating in these non-fertile strains. Taken together, our data demonstrate pheromone signaling activation by the Paracoccidioides a-pheromone through its receptor in this yeast model, which provides novel evidence for the existence of a functional mating signaling system in Paracoccidioides.MHJS and JFM were supported by Fundacão para a Ciência e Tecnologia (FCT) grants. This work was supported by a grant from FCT (PTDC/BIA-MIC/ 108309/2008)

An AI-based object detection approach for robotic competitions

Artificial Intelligence has been introduced in many applications, namely in artificial vision-based systems with object detection tasks. This paper presents an object localization system with a motivation to use it in autonomous mobile robots at robotics competitions. The system aims to allow robots to accomplish their tasks more efficiently. Object detection is performed using a camera and artificial intelligence based on the YOLOv4 Tiny detection model. An algorithm was developed that uses the data from the system to estimate the parameters of location, distance, and orientation based on the pinhole camera model and trigonometric modelling. It can be used in smart identification procedures of objects. Practical tests and results are presented, constantly locating the objects and with errors between 0.16 and 3.8 cm, concluding that the object localization system is adequate for autonomous mobile robots.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI (UIDB/05757/2020 and UIDP/05757/2020). The project that gave rise to these results received the support of a fellowship from ”la Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/DI20/11780028. João Braun is a PhD Student at the Faculty of Engineering, University of Porto (FEUP) supervised by Prof. Paulo Costa.info:eu-repo/semantics/publishedVersio

Controlling the pandemic during the SARS-CoV-2 vaccination rollout

© The Author(s) 2021. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.There is a consensus that mass vaccination against SARS-CoV-2 will ultimately end the COVID-19 pandemic. However, it is not clear when and which control measures can be relaxed during the rollout of vaccination programmes. We investigate relaxation scenarios using an age-structured transmission model that has been fitted to age-specific seroprevalence data, hospital admissions, and projected vaccination coverage for Portugal. Our analyses suggest that the pressing need to restart socioeconomic activities could lead to new pandemic waves, and that substantial control efforts prove necessary throughout 2021. Using knowledge on control measures introduced in 2020, we anticipate that relaxing measures completely or to the extent as in autumn 2020 could launch a wave starting in April 2021. Additional waves could be prevented altogether if measures are relaxed as in summer 2020 or in a step-wise manner throughout 2021. We discuss at which point the control of COVID-19 would be achieved for each scenario.G.R., J.V., A.N., M.C.G. were supported by Fundação para a Ciência e a Tecnologia (FCT) project reference 131_596787873, awarded to G.R. M.V. was supported by the European Union H2020 ERA project (No. 667824 - EXCELLtoINNOV). The contribution of C.H.v.D. was under the auspices of the US Department of Energy (contract number 89233218CNA000001) and supported by the National Institutes of Health (grant number R01-OD011095). MK acknowledges support from the Netherlands Organization for Health Research and Development (ZonMw) Grant no. 10430022010001.info:eu-repo/semantics/publishedVersio

Minimal Learning Machine: Theoretical Results and Clustering-Based Reference Point Selection

The Minimal Learning Machine (MLM) is a nonlinear supervised approach based on learning a linear mapping between distance matrices computed in the input and output data spaces, where distances are calculated using a subset of points called reference points. Its simple formulation has attracted several recent works on extensions and applications. In this paper, we aim to address some open questions related to the MLM. First, we detail theoretical aspects that assure the interpolation and universal approximation capabilities of the MLM, which were previously only empirically verified. Second, we identify the task of selecting reference points as having major importance for the MLM's generalization capability. Several clustering-based methods for reference point selection in regression scenarios are then proposed and analyzed. Based on an extensive empirical evaluation, we conclude that the evaluated methods are both scalable and useful. Specifically, for a small number of reference points, the clustering-based methods outperformed the standard random selection of the original MLM formulation.Comment: 29 pages, Accepted to JML