28 documents found, page 1 of 3
Housekeeping System for Suborbital Vehicles: VIRIATO Mock-Up Vehicle Integratio...
Rodrigues, Geraldo; Arribas, Beltran; Melício, Rui; Gordo, Paulo; Valério, Duarte; Casaleiro, J.; Silva, AndréThe work presented in this paper regards the improvement of a housekeeping system for data acquisition of a suborbital vehicle (VIRIATO rocket or launcher). The specifications regarding the vehicle are presented and hardware is chosen accordingly, considering commercial off-the-shelf components. Mechanical and thermal simulations are performed regarding the designed system and a physical prototype is manufactur...
Space debris generation in GEO: Space materials testing and evaluation
Duzellier, Sophie; Gordo, Paulo; Melicio, Rui; Valério, Duarte; Millinger, Mark; Amorim, AntónioThe aim of this work is to evaluate what happens to the spacecraft materials beyond the spacecraft End of Life. A review of spacecraft external materials and effects of space environment is presented. This paper results from a continued study on spacecraft material degradation, and space debris formation in geostationary orbit (GEO). In this paper a 20-year GEO dose profile that combines simultaneous UV, partic...
An Overview of Mathematical Modelling in Cancer Research
Vieira, Lourenço Côrte; Costa, Rafael S.; Valério, DuarteCancer is a complex disease, responsible for a significant portion of global deaths. The increasing prioritisation of know-why over know-how approaches in biological research has favoured the rising use of both white- and black-box mathematical techniques for cancer modelling, seeking to better grasp the multi-scale mechanistic workings of its complex phenomena (such as tumour-immune interactions, drug resistan...
Machine learning and natural language processing for prediction of human factor...
Madeira, Tomás; Melício, Rui; Valério, Duarte; Santos, LuisIn the aviation sector, human factors are the primary cause of safety incidents. Intelligent prediction systems, which are capable of evaluating human state and managing risk, have been developed over the years to identify and prevent human factors. However, the lack of large useful labelled data has often been a drawback to the development of these systems. This study presents a methodology to identify and cla...
Fractional Order Processing of Satellite Images
Henriques, Manuel; Valério, Duarte; Melício, RuiNowadays, satellite images are used in many applications, and their automatic processing is vital. Conventional integer grey-scale edge detection algorithms are often used for this. This study shows that the use of color-based, fractional order edge detection may enhance the results obtained using conventional techniques in satellite images. It also shows that it is possible to find a fixed set of parameters, a...
Fractional order color image processing
Henriques, Manuel; Valério, Duarte; Gordo, Paulo; Melício, RuiMany image processing algorithms make use of derivatives. In such cases, fractional derivatives allow an extra degree of freedom, which can be used to obtain better results in applications such as edge detection. Published literature concentrates on grey-scale images; in this paper, algorithms of six fractional detectors for colour images are implemented, and their performance is illustrated. The algorithms are...
IPOscore: an interactive web-based platform for postoperative surgical complica...
Mochão, Hugo; Gonçalves, Daniel; Alexandre, Leonardo; Castro, Carolina; Valério, Duarte; Barahona, Pedro; Moreira-Gonçalves, Daniel; Costa, Paulo M.Background: The performance of traditional risk score systems to predict (post)-operative outcomes is limited. This weakness reduces confidence in its use to support clinical risk mitigation decisions. However, the rapid growth of health data in the last years offers principles to deal with some of these limitations. In this regard, the data allows the extraction of relevant information for both patients strati...
A wind turbine and its robust control using the CRONE method
Ravasco, Francisco; Melício, Rui; Batista, Nelson; Valério, DuarteThis paper presents the identification, development and simulation of a complex order, third generation CRONE (Commande Robuste d’Ordre Non Entier) controller for a new Darrieus type vertical-axis wind turbine design. A prototype of this wind turbine was developed and tested in a wind tunnel. Data acquired in the tests were used to develop and validate an accurate model. The CRONE control system design methodol...
GA Optimized Fractional Controller for a Wind Turbine Ride Through Pitch Malfun...
Pandiyan, Surya; Valério, Duarte; Melício, Rui; Mendes, VictorThis paper is about better integration of wind energy into an electric grid, avoiding wind turbine pitch malfunction to become a failure. A fractional-order controller is used in the two-level converters of the wind turbine to reduce the voltage drops during the malfunction. The reduction is attained by an optimization problem for selection of the parameters of the fractional-order control. The optimization pro...
Dynamic modeling of bone remodeling, osteolytic metastasis and PK/PD therapy: i...
Neto, Joana Pinheiro; Alho, Irina; Costa, Luis; Casimiro, Sandra; Valério, Duarte; Vinga, SusanaBone is constantly being renewed: in the adult skeleton, bone resorption and formation are in a tightly coupled balance, allowing for a constant bone density to be maintained. Yet this micro-environment provides the necessary conditions for the growth and proliferation of tumor cells, and thus bone is a common site for the development of metastases, mainly from primary breast and prostate cancer. Mathematical a...