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Publications

2024

MANTIS: UAV for Indoor Logistic Operations

Authors
Dias, A; Martins, JJ; Antunes, J; Moura, A; Almeida, J;

Publication
2024 7TH IBERIAN ROBOTICS CONFERENCE, ROBOT 2024

Abstract
This paper presents the Unmanned Aerial Vehicle (UAV) MANTIS, developed for indoor inventory management in large-scale warehouses. MANTIS integrates a visual odometry (VIO) system for precise localization, thus allowing indoor navigation in complex environments. The mechanical design was optimized for stability and maneuverability in confined spaces, incorporating a lightweight frame and efficient propulsion system. The UAV is equipped with an array of sensors, including a 2D LiDAR, six cameras, and two IMUs, which ensures accurate data collection. The VIO system integrates visual data with inertial measurements to maintain robust, drift-free localization. A behavior tree (BT) framework is responsible for the UAV mission planner assigned to the vehicle, which can be flexible and adaptive in response to dynamic warehouse conditions. To validate the accuracy and reliability of the VIO system, we conducted a series of tests using an OptiTrack motion capture system as a ground truth reference. Comparative analysis between the VIO and OptiTrack data demonstrates the efficacy of the VIO system in maintaining accurate localization. The results prove MANTIS, with the required payload sensors, is a viable solution for efficient and autonomous inventory management.

2024

Are Aptamer-Based Biosensors the Future of the Detection of the Human Gut Microbiome?-A Systematic Review and Meta-Analysis

Authors
Moreira, MJ; Pintado, M; De Almeida, JMMM;

Publication
BIOSENSORS-BASEL

Abstract
The gut microbiome is shaped early in life by dietary and lifestyle factors. Specific compounds in the gut affect the growth of different bacterial species and the production of beneficial or harmful byproducts. Dysbiosis of the gut microbiome has been linked to various diseases resulting from the presence of harmful bacteria and their byproducts. Existing methods for detecting microbial species, such as microscopic observation and molecular biological techniques, are costly, labor-intensive, and require skilled personnel. Biosensors, which integrate a recognition element, transducer, amplifier, signal processor, and display unit, can convert biological events into electronic signals. This review provides a comprehensive and systematic survey of scientific publications from 2018 to June 2024, obtained from ScienceDirect, PubMed, and Scopus databases. The aim was to evaluate the current state-of-the-art and identify knowledge gaps in the application of aptamer biosensors for the determination of gut microbiota. A total of 13 eligible publications were categorized based on the type of study: those using microbial bioreceptors (category 1) and those using aptamer bioreceptors (category 2) for the determination of gut microbiota. Point-of-care biosensors are being developed to monitor changes in metabolites that may lead to disease. They are well-suited for use in the healthcare system and offer an excellent alternative to traditional methods. Aptamers are gaining attention due to their stability, specificity, scalability, reproducibility, low production cost, and low immunogenicity. While there is limited research on using aptamers to detect human gut microbiota, they show promise for providing accurate, robust, and cost-effective diagnostic methods for monitoring the gut microbiome.

2024

Exploring students' opinion on software testing courses

Authors
Cammaerts, F; Tramontana, P; Paiva, ACR; Flores, N; Ricós, FP; Snoeck, M;

Publication
PROCEEDINGS OF 2024 28TH INTERNATION CONFERENCE ON EVALUATION AND ASSESSMENT IN SOFTWARE ENGINEERING, EASE 2024

Abstract
Software testing is an important part of the software development lifecycle. As it is a highly sought-after skill in the industry, it is not surprising that there has been a great deal of research into the teaching of software testing in higher education. Most of this research proposes or evaluates pedagogical approaches or software testing tools to assist teachers in educating the next generation of software engineers. These evaluations are often limited to measuring teachers' opinions about the use of a novel pedagogical approach or an educational tool and students' acceptance and performance in terms of desired software testing skills. While tools and pedagogical approaches address specific aspects of a course, to date, little attention has been paid to the opinions of the students about all the individual aspects of a software testing course. This paper aims to address this missing student perspective by taking a holistic view of software testing course designs. To address this gap, an exploratory study was performed by distributing a questionnaire to 103 students from ten different courses to gauge their opinions on a software testing course they are enrolled in. The results show that students generally have a positive perception of the different aspects of their software testing course. However, several areas for improvement were suggested based on the gathered data.

2024

Four-of-a-kind? Comprehensive atmospheric characterisation of the HR 8799 planets with VLTI/GRAVITY

Authors
Nasedkin, E; Mollière, P; Lacour, S; Nowak, M; Kreidberg, L; Stolker, T; Wang, JJ; Balmer, WO; Kammerer, J; Shangguan, J; Abuter, R; Amorim, A; Asensio-Torres, R; Benisty, M; Berger, JP; Beust, H; Blunt, S; Boccaletti, A; Bonnefoy, M; Bonnet, H; Bordoni, MS; Bourdarot, G; Brandner, W; Cantalloube, F; Caselli, P; Charnay, B; Chauvin, G; Chavez, A; Choquet, E; Christiaens, V; Clenet, Y; du Foresto, VC; Cridland, A; Davies, R; Dembet, R; Dexter, J; Drescher, A; Duvert, G; Eckart, A; Eisenhauer, F; Schreiber, NMF; Garcia, P; Lopez, RG; Gendron, E; Genzel, R; Gillessen, S; Girard, JH; Grant, S; Haubois, X; Heissel, G; Henning, T; Hinkley, S; Hippler, S; Houlle, M; Hubert, Z; Jocou, L; Keppler, M; Kervella, P; Kurtovic, NT; Lagrange, AM; Lapeyrere, V; Le Bouquin, JB; Lutz, D; Maire, AL; Mang, F; Marleau, GD; Merand, A; Monnier, JD; Mordasini, C; Ott, T; Otten, GPPL; Paladini, C; Paumard, T; Perraut, K; Perrin, G; Pfuhl, O; Pourre, N; Pueyo, L; Ribeiro, DC; Rickman, E; Ruffio, JB; Rustamkulov, Z; Shimizu, T; Sing, D; Stadler, J; Straub, O; Straubmeier, C; Sturm, E; Tacconi, LJ; van Dishoeck, EF; Vigan, A; Vincent, F; von Fellenberg, SD; Widmann, F; Winterhalder, TO; Woillez, J; Yazici, S;

Publication
ASTRONOMY & ASTROPHYSICS

Abstract
With four companions at separations from 16 to 71 au, HR 8799 is a unique target for direct imaging, presenting an opportunity for a comparative study of exoplanets with a shared formation history. Combining new VLTI/GRAVITY observations obtained within the ExoGRAVITY program with archival data, we performed a systematic atmospheric characterisation across all four planets. We explored different levels of model flexibility to understand the temperature structure, chemistry, and clouds of each planet using both petitRADTRANS atmospheric retrievals and fits to self-consistent radiative-convective equilibrium models. Using Bayesian model averaging to combine multiple retrievals (a total of 89 across all four planets), we find that the HR 8799 planets are highly enriched in metals, with [M/H] greater than or similar to 1, and have stellar to superstellar atmospheric C/O ratios. The C/O ratio increases with increasing separation from 0.55(-0.10)(+0.12) for d to 0.78(-0.04)(+0.03) for b, with the exception of the innermost planet, which has a C/O ratio of 0.87 +/- 0.03. Such high metallicities are unexpected for these massive planets, and challenge planet-formation models. By retrieving a quench pressure and using a disequilibrium chemistry model, we derive vertical mixing strengths compatible with predictions for high-metallicity, self-luminous atmospheres. Bayesian evidence comparisons strongly favour the presence of HCN in HR 8799 c and e, as well as CH4 in HR 8799 c, with detections at > 5 sigma confidence. All of the planets are cloudy, with no evidence of patchiness. The clouds of c, d, and e are best fit by silicate clouds lying above a deep iron cloud layer, while the clouds of the cooler HR 8799 b are more likely composed of Na2S. With well-defined atmospheric properties, future exploration of this system is well positioned to unveil further details of these planets, extending our understanding of the composition, structure, and formation history of these siblings.

2024

Determination of Effective Connectivity of Brain Activity in the Resting Brain

Authors
Azevedo, CP; Salgado, PA; Perdicoúlis, TPA; dos Santos, PL;

Publication
WIRELESS MOBILE COMMUNICATION AND HEALTHCARE, MOBIHEALTH 2023

Abstract
The resting brain has been extensively investigated for low frequency synchrony between brain regions, namely Functional Connectivity. However the other main stream of the brain connectivity analysis that seeks causal interactions between brain regions, Effective Connectivity, has been still little explored. Inherent complexity of brain activities in resting-state, as observed in Blood Oxygenation-Level Dependant fluctuations, calls for exploratory methods for characterizing these causal networks [1]. To determine the structure of the network that causes this dynamics, it is developed a method of identification based on least squares, which assumes knowledge of the signals of brain activity in different regions. As there is no access to functional Magnetic Resonance Imaging, data it is developed a model to obtain the Blood Oxygenation Level Dependent signals and it is implemented a reverse hemo-dynamic function. To assess the performance of the created model Monte Carlo simulations have been used.

2024

Deep Reinforcement Learning Framework for UAV Indoor Navigation

Authors
Martins, JJ; Amaral, A; Dias, A;

Publication
2024 7TH IBERIAN ROBOTICS CONFERENCE, ROBOT 2024

Abstract
Unmanned Aerial Vehicle (UAV) applications, particularly for indoor tasks such as inventory management, infrastructure inspection, and emergency response, are becoming increasingly complex with dynamic environments and their different elements. During operation, the vehicle's response depends on various decisions regarding its surroundings and the task goal. Reinforcement Learning techniques can solve this decision problem by helping build more reactive, adaptive, and efficient navigation operations. This paper presents a framework to simulate the navigation of a UAV in an operational environment, training and testing it with reinforcement learning models for further deployment in the real drone. With the support of the 3D simulator Gazebo and the framework Robot Operating System (ROS), we developed a training environment conceivably simple and fast or more complex and dynamic, explicit as the real-world scenario. The multi-environment simulation runs in parallel with the Deep Reinforcement Learning (DRL) algorithm to provide feedback for the training. TD3, DDPG, PPO, and PPO+LSTM were trained to validate the framework training, testing, and deployment in an indoor scenario.

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