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- Smart Structures and Materials Selected Papers from the 7th ECCOMAS Thematic Conference on Smart Structures and MaterialsPublication . Araújo, Aurélio L.; Soares, Carlos A. MotaThis work was compiled with expanded and reviewed contributions from the 7th ECCOMAS Thematic Conference on Smart Structures and Materials, that was held from 3 to 6 June 2015 at Ponta Delgada, Azores, Portugal. The Conference provided a comprehensive forum for discussing the current state of the art in the field as well as generating inspiration for future ideas specifically on a multidisciplinary level. The scope of the Conference included topics related to the following areas: Fundamentals of smart materials and structures; Modeling/formulation and characterization of smart actuators, sensors and smart material systems; Trends and developments in diverse areas such as material science including composite materials, intelligent hydrogels, interfacial phenomena, phase boundaries and boundary layers of phase boundaries, control, micro- and nano-systems, electronics, etc. to be considered for smart systems; Comparative evaluation of different smart actuators and sensors; Analysis of structural concepts and designs in terms of their adaptability to smart technologies; Design and development of smart structures and systems; Biomimetic phenomena and their inspiration in engineering; Fabrication and testing of smart structures and systems; Applications of smart materials, structures and related technology; Smart robots; Morphing wings and smart aircrafts; Artificial muscles and biomedical applications; Smart structures in mechatronics; and Energy harvesting.
- Design of an Underactuated USV CatamaranPublication . Assunção, Mário; Teodoro, Pedro; Marat-Mendes, Rosa; Franco, VictorThe Sea2Future program was developed at ENIDH, since 2018, and it has involved the construction of an unmanned surface vehicle (USV) with the participation of students and teachers of this educational institution. This firstUSV, with two hulls, referred to as USV-enautica1, included a control system which allows it to carry out several functions autonomously and it was used to study the composite construction, the propulsion command and control architectures, the navigation algorithms, and the control systems. The challenge of designing a lightweight hull suitable for coastal and open ocean navigation is described and the implemented solution for the microcontroller and software operation, the sensors, the navigation, and the control systems are explained. The USV has successfully demonstrated its ability to be operated remotely, which is necessary to validate the hydrodynamic parameters, and afterwards the aim of autonomous operation.
- Risk Driven Semantic Interoperability in the Maritime Surveillance DomainPublication . Marques, Fernando Sérgio Bryton Dias; Martínez, Jesús; Delgado, Olga; Arriaga, GonzaloSemantic Interoperability (SI) is essential for organizations as to share information, via computer systems, without which their efficiency and effectiveness is hampered. Assuming multiple actions for enhancing SI are possible, and that resources are usually scarce, the more relevant ones should have higher priority. Since information sharing, in the maritime surveillance domain, is essential for dealing with risks, such as irregular migration or piracy, this paper presents a method for prioritizing SI development actions based on the risks they aim to address. The method was developed by following the Design Science Research strategy, is based on the Delphi method and the Weighted Sum Model, and was validated in a real environment, with six organizations involved in maritime surveillance. The method aims to foster information sharing by supporting the development of action plans for enhancing SI, which may deliver relevant results faster, cheaper and less risky than traditional approaches.
- Data Based Modeling of a Large Scale Water Delivery SystemPublication . Fernandes, Marta; Oliveira, Paulo; Vieira, Susana; Mendonça, Luís; Nabais, João Lemos; Botto, Miguel AyalaWater is a vital resource and the growing populations and economies around the globe are pushing its demand worldwide. Therefore, the water conveyance operation should be well managed and improved. This paper proposes the development of reliable models able to predict water levels of a real 24.4 km water delivery channel in real time. This is a difficult task because this is a time-delayed dynamical system distributed over a long distance with nonlinear characteristics and external perturbations. Artificial neural networks are used, which are a well-known modeling technique that has been applied to complex and nonlinear systems. Real data is used for the design and validation of the models. The model obtained has the ability to predict water levels along the channel with minimum error, which can result in significant reduction of wasted water when implementing an automatic controller.
- Ensemble fuzzy models in personalized medicine: Application to vasopressors administrationPublication . Salgado, Cátia M.; Vieira, Susana M.; Mendonça, Luís; Finkelstein, Stan; Sousa, João M.C.Vasopressors administration in intensive care units is a risky surgical procedure that can be associated with infections, especially if done urgently such as in the case of unexpected systemic shock. The early prediction of a patient׳s transition to vasopressor dependence could improve overall outcomes associated with the procedure. Personalized medicine in the ICU encompasses the customization of healthcare on the level of individual patients, with diagnostic tests, monitoring interventions and treatments being fitted to the individual rather than the “average” patient. In this scope, this paper proposes an ensemble fuzzy modeling approach to a classification problem based on subgroups of patients identified by individual characteristics. A fuzzy c-means clustering algorithm was implemented to find subgroups of patients and each subgroup was used to develop a fuzzy model. The final classification of the ensemble fuzzy approach is obtained using two output selection criteria: an a priori decision criterion based on the distance from the cluster centers to the patients׳ characteristics, and an a posteriori decision criterion based on the uncertainty of the model output. The performance of the proposed approach is investigated using a real world clinical database and nine benchmark datasets. The ensemble fuzzy model approach performs better than the single model for the prediction of vasopressors administration in the ICU, being the a posteriori approach the best performer, with an average AUC of 0.85, showing this way the advantage of a personalized approach for patient care in the ICU.
- Advances in Engineering SoftwarePublication . Madeira, J.F. Aguilar; Camotim, D.; Basaglia, C.; Santos, J.V. Araujo dos; Lopes, H.M.R.; Topping, B. H. V.; Pina, H.; Poroseva, S. V.; Mota, Soares, C. M.; Araújo, A. L.; Moleiro, Duarte, F.; Sarrate, J.; Ledoux, F.; Kruis, J.; Dumont, S.; Lebon, F.
- Deformation prediction of composite specimens subjected to three-point bending testsPublication . Monte, Sara M. C.; Infante, Vírginia; Moleiro, F.; Madeira, J. F. A.A computational and experimental study was carried out in order to determine the deformations of specimens made in laminated composite material when subjected to three - point bending test. The specimens were produced using unidirectional carbon fiber prepreg with different aspect ratios and different lamination schemes. The experimental deformations of the bending tests were obtained using an innovative method called digital image correlation. At the computational level, two models were compared: the first developed in ANSYS and the second, not available in any commercial program, developed by MOLEIRO, 2010.The latter presents a mixed Layerwise formulation that assumes displacements and transverse stresses as independent variables, and therefore is able to a priori fulfill the interlaminar continuity C^0 of tranverse stresses and displacements. ANSYS model uses a solid element, in the laminated structural version, and assumes a displacement formulation. It was concluded that the ANSYS model results are more similar to the experimental results of longer specimens and the Layerwise mixed model results are more similar to the experimental results of shorter specimens.
- Buckling and Geometrically Nonlinear Analysis of Sandwich StructuresPublication . Moita, J. S.; Araújo, A. L.; Correia, Victor M. Franco; Soares, C. M. Mota; Soares, C. A. MotaIn this work a finite element model is presented for buckling and nonlinear analysis of multilayer sandwich plates and shells, with a soft core sandwiched between stiff elastic layers. The finite element is obtained by assembling all element-layers through the thickness using specific assumptions on the displacement continuity at the interfaces between layers, but allowing for different behaviors of the layers. The stiff elastic layers are modelled using the classic plate theory and the core is modelled using Reddy׳s third order shear deformation theory. The present finite element model is a non-conforming triangular plate/shell element with 24 degrees of freedom for the generalized displacements. This model is applied in the solution of illustrative examples and the results are presented and discussed.
- Uplink Performance Evaluation of Broadband Systems which Adopt a Massive MU-MIMO ApproachPublication . Torres, Paulo; Charrua, Luis; Gusmão, AntonioThis paper deals with an Orthogonal Frequency Division Multiplexing (OFDM)-based uplink within a Multi User (MU)-Multi-Input Multi-Output (MIMO) system where a ”massive MIMO” approach” is adopted. In this context, either an optimum Minimum Mean-Squared Error (MMSE) linear detection or a reduced-complexity Matched Filter (MF) linear detection are considered. Regarding performance evaluation by simulation, several semi-analytical methods are proposed: one performance evaluation method in the optimum (MMSE) case; two performance evaluation methods in the MF case. This paper includes performance results for uncoded 4-Quadrature Amplitude Modulation (QAM)/OFDM transmission and a MUMIMO channel with uncorrelated Rayleigh fading, under the assumptions of perfect power control and perfect channel estimation. The accuracy of performance results obtained through the semi-analytical simulation methods is assessed by means of parallel conventional Monte Carlo simulations [10]. The performance resultsare discussed indetail andwe also emphasize the achievable ”massive MIMO” effects, even for the reducedcomplexity detection techniques, provided that the number of BS antennas is much higher than the number of antennas which are jointly employed in the terminals of the multiple autonomous users.
- Computers and StructuresPublication . Camotin, C.; Basaglia, C.; Madeira, J. F. Aguilar; Pina, H.; Ilanko, S.; Kennedy, D.; Rabczuk, T.; Soares, C. M. Mota; Araújo, A. L.; Duarte, F. M.; Pallares, L.; Pallares, F. J.; B. H. V.