Analytical Model for the Performance Curves of a Family of Propellers Based on Wind Tunnel Tests

Propeller aircraft performance is greatly influenced by the performance of the propeller it uses. Thus, proper selection of a propeller for a given aircraft design at the early stages of the design process is fundamental. During the design of a new aircraft, simple yet accurate performance models are required to properly optimize the design. Significant experimental performance data of low speed, small propellers is available. The main objective of this work is to create and validate an analytical model for     the performance curves of a family of propellers tested at low Reynolds numbers, which can be used in selecting a propeller for a given existing aircraft design or during its design optimization process. This kind of propellers is more commonly used in Unmanned Aerial Vehicles (UAVs). The model is designed in MATLAB® using a variety of regression techniques, such as the Least Squares Method (LSQ), applied to experimental data acquired at University of Illinois at Urbana-Champaign (UIUC), for seventeen APC Thin Electric propellers, and at the Department of Aerospace Sciences (DCA) of University of Beira Interior (UBI), for ten more APC Thin Electric propellers. The analytical model predicts propeller power coefficient and propulsive efficiency accurately for the family of propellers tested and can also be used for the propellers with dimensions close to those used for its development. The propeller performance data obtained during the experimental tests are made available the community to further increase the documentation on propellers tested at low Reynolds numbers. Keywords: Propeller, Low Reynolds propeller performance, Propeller tests, Wind tunne

Seminal traits, suitability for semen preservation and fertility in the native Portuguese horse breeds Puro Sangue Lusitano and Sorraia: Implications for stallion classification and assisted reproduction

The Puro Sangue Lusitano (PSL) is the major national breed of horse in Portugal, but no studies exist on its seminal characteristics, or on the possibility of conserving semen for future use. The aim of this study was to evaluate semen parameters, fertility and the aptness to semen preservation in Lusitano Stallions. In order to compare characteristics defined by a single or by multiple semen collections per stallion 152 ejaculates obtained from 152 Lusitano stallions presented at an annual breeding soundness examination as well as data related to 371 ejaculates obtained from 9 PSL were analyzed. These latter samples were also evaluated in terms of their possible use in assisted reproduction and were compared with 113 ejaculates obtained from 4 Sorraia horses, a rare and endangered Portuguese breed. The percentage of motile spermatozoa (PMS) was assessed after collection (AC), after semen dilution (AD) and at 24 h of cool-storage. Mean values obtained for sperm motility and morphology and semen pH observed after semen collection differ significantly (P < 0.05) between single collection/multiple stallions and multiple collections/limited stallions, and no age related effects were detected. Overall, Lusitano semen quality was comparable to that of related breeds, while Sorraia stallions had very poor semen quality. The response to cool-storage of diluted semen samples differed among stallions and breeds, and the best results for progressive motile sperm cells at 24 h were in a range of 35-53% for PSL stallions and were lower for Sorraia stallions. Fertility rates obtained with artificial insemination (AI) averaged at 85% for PSL. With the exception of PMS AC, sperm vitality and semen pH no other seminal trait seemed to influence fertility rates in the Lusitano breed.http://www.sciencedirect.com/science/article/B6T43-4SPJ1TD-3/1/6a0fc54305a5730ccff6ba975a4abd0

Towards Segmentation and Labelling of Motion Data in Manufacturing Scenarios

Publisher Copyright: © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.There is a significant interest to evaluate the occupational exposure that manufacturing operators are subjected throughout the working day. The objective evaluation of occupational exposure with direct measurements and the need for automatic annotation of relevant events arose. The current work proposes the use of a self similarity matrix (SSM) as a tool to flag events that may be of importance to be analyzed by ergonomic teams. This way, data directly retrieved from the work environment will be summarized and segmented into sub-sequences of interest over a multi-timescale approach. The process occurs under 3 timescale levels: Active working periods, working cycles, and in-cycle activities. The novelty function was used to segment non-active and active working periods with an F1-score of 95%. while the similarity function was used to correctly segment 98% of working cycle with a duration error of 6.12%. In addition, this method was extended into examples of multi time scale segmentation with the intent of providing a summary of a time series as well as support in data labeling tasks, by means of a query-by-example process to detect all subsequences.authorsversionpublishe

Problématique du placement de tâches dans MeDLey

La programmation d'applications parallèles basées sur le modèle d'échange de messages est simple à apprendre, mais nécessite un investissement considérable pour développer des applications complexes et obtenir de bonnes performances. Afin d'aider le programmeur dans ce contexte, nous proposons un environnement de développement et d'exécution, partiellement réalisé, composé de quatre parties principales: un module gérant la communication des messages, un placeur de tâches, un analyseur de traces et un module lié à l'administration de réseaux. Ce document a pour but de présenter les problèmes spécifiques au placement au sein de cet environnement en effectuant d'abord un survol général du domaine de placement de tâches, puis une description plus détaillée de différents modules de l'environnement

Uncertainty-Based Rejection in Machine Learning: Implications for Model Development and Interpretability

POCI-01-0247-FEDER-033479Uncertainty is present in every single prediction of Machine Learning (ML) models. Uncertainty Quantification (UQ) is arguably relevant, in particular for safety-critical applications. Prior research focused on the development of methods to quantify uncertainty; however, less attention has been given to how to leverage the knowledge of uncertainty in the process of model development. This work focused on applying UQ into practice, closing the gap of its utility in the ML pipeline and giving insights into how UQ is used to improve model development and its interpretability. We identified three main research questions: (1) How can UQ contribute to choosing the most suitable model for a given classification task? (2) Can UQ be used to combine different models in a principled manner? (3) Can visualization techniques improve UQ’s interpretability? These questions are answered by applying several methods to quantify uncertainty in both a simulated dataset and a real-world dataset of Human Activity Recognition (HAR). Our results showed that uncertainty quantification can increase model robustness and interpretability.publishersversionpublishe

Impact of power ultrasound on chemical and physicochemical quality indicators of strawberries dried by convection

[EN] A study on the quality parameters of strawberries dehydrated by convection assisted by power ultrasound (US) at 40 70 C and 30 and 60W has been carried out for the first time. In general, the quality of US-treated samples was higher than that of commercial samples. Even under the most severe conditions used (US at 70 C and 60 W), high values of vitamin C retention (>65%) and scarce advance of Maillard reaction (2-furoylmethyl derivatives of Lys and Arg < 90 mg 100 g 1 protein) were observed. Rehydration ratio was not affected by the power applied and the obtained values were similar to those of convectively-treated samples. According to the results here presented, US is a suitable example of an emerging and environmentally friendly technology that accelerates convective drying, allowing the obtainment of dried strawberries with premium quality.This work has been funded by Ministry of Economy and Competitiveness of Spain and ERDF (FEDER) (Project DPI2012-37466-C03-03), Fun-c-Food (CSD2007-00063 Consolider-INGENIO 2010), CYTED IBEROFUN (P109AC0302) and Comunidad de Valencia, Project PROMETEO/2010/062. J.G.S. also thanks CSIC and the EU for a predoctoral JAE grant. A.C.S. thanks the Spanish Ministry of Economy and Competitiveness for a Ramon y Cajal contract.Gamboa-Santos, J.; Montilla, A.; Cortijo Soria, A.; Cárcel Carrión, JA.; García Pérez, JV.; Villamiel, M. (2014). Impact of power ultrasound on chemical and physicochemical quality indicators of strawberries dried by convection. Food Chemistry. 161:40-46. https://doi.org/10.1016/j.foodchem.2014.03.106S404616

An infrastructure-free magnetic-based indoor positioning system with deep learning

POCI-01-0247-FEDER-033479Infrastructure-free Indoor Positioning Systems (IPS) are becoming popular due to their scalability and a wide range of applications. Such systems often rely on deployed Wi-Fi networks. However, their usability may be compromised, either due to scanning restrictions from recent Android versions or the proliferation of 5G technology. This raises the need for new infrastructure-free IPS independent of Wi-Fi networks. In this paper, we propose the use of magnetic field data for IPS, through Deep Neural Networks (DNN). Firstly, a dataset of human indoor trajectories was collected with different smartphones. Afterwards, a magnetic fingerprint was constructed and relevant features were extracted to train a DNN that returns a probability map of a user’s location. Finally, two postprocessing methods were applied to obtain the most probable location regions. We asserted the performance of our solution against a test dataset, which produced a Success Rate of around 80%. We believe that these results are competitive for an IPS based on a single sensing source. Moreover, the magnetic field can be used as an additional information layer to increase the robustness and redundancy of current multi-source IPS.publishersversionpublishe

Polimorfismos nos exões 2 e 3 da O6 - alquilguanina DNA alquiltransferase em populações pacientes e não pacientes do foro oncológico

Dissertação mest., Biotecnologia, Universidade do Algarve, 2010Os agentes alquilantes atacam o oxigénio na posição 6 da guanina no DNA, dando origem à O6-alquilguanina, uma lesão que conduz a mutações do tipo transição G:C para A:T. A reparação destas lesões mutagénicas é efectuada pela proteína MGMT mediante um processo estequiométrico, irreversível e único, transferindo os aductos mutagénicos da posição O6 da guanina para uma cisteína alquil receptora localizada na posição 145, protegendo as células da mutagénese, morte celular e carcinogenese provocada pelos agentes alquilantes. Mas se por um lado, a MGMT, preserva a integridade genómica, por outro cria resistências à utilização de agentes alquilantes como anti-neoplásicos. Com este estudo pretende-se identificar os polimorfismos existentes nos exões 2 e 3 da MGMT em 135 amostras (70 oncológicas e 65 não oncológicas) do universo da população residente no Algarve, e avaliar a relação existente entre os vários genótipos encontrados e o aparecimento da patologia oncológica. Não foram identificados polimorfismos no exão 2. No exão 3 foram identificados dois polimorfismos, C2740123T (Leu53Leu) e C2740214T (Leu84Phe), ligados geneticamente, e que apresentam uma frequência alélica de 0,12. Os resultados apontam para um decréscimo da possibilidade de aparecimento de cancro nos indivíduos portadores de um ou mais alelos polimórficos (OR ajustado = 0.149, IC 95%, 0.043 - 0.518) quando são comparados com os portadores de alelos selvagens. Em particular do sexo feminino (OR ajustado = 0.103, IC 95%, 0.017 - 0.626). Considera-se que a presença deste dois polimorfismos em conjunto diminuem o potencial risco de aparecimento de cancro. Estudos mais alargados devem ser feitos para validar a nossa conclusão