Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Coastal erosion mitigation based on artificial nourishments and sand bypassing systems: Barra-Vagueira, Portugal

Barra-Vagueira coastal stretch, located downdrift of the Aveiro Harbour, NW coast of Portugal, is anerosion hotspot, presenting,in the last 50 years,erosion rates that reached 8m/year(Santoset al.,2014).Thiscoast is subject to a very energetic wave climate, inducing a net littoral transport from North to South that reaches valuesaround 106m3/year(Santos et al., 2014).Inthe last two decades, artificial nourishments have become the most common coastal erosion mitigation strategyat this site, being performed low-frequency shots,summing several million cubic meters of sediments(Pinto et al., 2020).In 2014, the PortugueseLittoral Working Group(Santos el al., 2014)has recommended artificial nourishments as the main strategy to reduce the deficit of sediments on the littoral driftand tocounter theshoreline retreat. The present study aimsto assessboth the impact of artificial nourishments performed at south of the Aveiro harbour inlet and sand bypassing systems at the inlet,on the morphological evolution of the stretch Barra-Vagueira, consideringtheir performance and longevity. The studywas performed through the application of the numerical modelsLTC-Long Term Configuration(Coelho, 2005), to simulate the shoreline evolution,and CS-Model(Larsonet al., 2016), tosimulate the cross-shore profile evolution, bothin a 30yearsperspective(2020-2050).Themethodology adopted in thisstudy and the assessed scenariosis primary described,in the next section. The following sections describe the calibration and validation of the models and the results of theimpact of the intervention scenarios in the morphology of the coastal stretch. Finally, the major conclusions are presented

Applicability of Dynamic Inflow Models of HAWT in Yawed Flow Conditions

Horizontal axis wind turbines (HAWTs) experience yaw misalignments due to the physical limitations of yaw controllers and various novel active yaw controls. Moreover, the motion of floating offshore wind turbines (FOWTs) accelerates yaw misalignment. The blade element momentum (BEM) method is widely used due to its computational efficiency for the design of HAWTs. Momentum theory, the basis of BEM, assumes steady flow and uniform induction field at the disc. Those assumptions are relaxed by engineering models to capture yaw and unsteady effects. Current yaw engineering models, however, are inaccurate since they do not capture the asymmetric wake expansion effect. Dynamic inflow models have been developed for non-yawed flow. Furthermore, the AVATAR project shows that BEM using fully coupled engineering models, the current yaw, dynamic inflow and various engineering models, suffers from significant deficiencies. This purpose of this paper, therefore, is to investigate dynamic effects for yawed flow, and determine if current dynamic inflow models are applicable in yawed conditions. The Glauert’s modified momentum theory is applied to dynamic inflow models to couple the two models. Among all coupled models, Øye, Yu PWVM and Yu FWVM DIM can capture asymmetric trends. However, the results show the significant deficiencies in phase delay on the actuator disc.Wind Energ

3D wake dynamics of the VAWT: Experimental and numerical investigation

The Vertical Axis Wind Turbine, in its 2D form, is characterized by a complex unsteady aerodynamic flow, including dynamic stall and blade vortex interaction. Adding to this complexity, the 3D flow causes spanwise effects and the presence of trailing vorticity and tip vortices. The objective of the current paper is to bring insight into the 3D development of the near wake of a H-VAWT, understanding: \u95 The spanwise blade load distribution in the upwind and the downwind blade passages. \u95 The trajectory of tip vortices, including the inboard movement and the radial expansion of the shed and the trailing vorticity. \u95 The impact of the 3D flow phenomena on the efficiency of the VAWT. \u95 The blade vortex interaction of the upwind tip vortex with the downwind blade passage. \u95 The induction due to trailing vorticity. The investigation is composed of experimental wind tunnel research with Stereo-PIV and modeling of the rotor and wake with a 3D unsteady panel method. A two bladed H-Darrieus VAWT model is tested in the low speed/low turbulence wind tunnel at Delft University of Technology. Stereo-PIV measurements are used to visualize the flow in the near wake focusing on the flow field around four tip geometries. The measurement planes cover several sections of the rotor volume, allowing for the reconstruction of the evolution of the tip vortex. The formation, the convection and the dissipation for each tip vortex are quantified. The experimental PIV data is used to validate the 3D, unsteady, multi-body, free-wake panel method. The combination of the results of the panel model validated by experiments, in particular the Stereo PIV results, allows to understand the impact of the near wake development on the upwind blade passage, as well as the energy conversion process during the downwind blade passage.Aerodynamics, Wind Energy & PropulsionAerospace Engineerin

Aerodynamic Analysis of a Vertical Axis Wind Turbine in a Diffuser

Wind energy in the urban environment faces complex and often unfavorable wind conditions. High turbulence, lower average wind velocities and rapid changes in the wind direction are common phenomena in the complex built environments. A possible way to improve the cost-efficiency of urban wind turbines is the application of flowenhancing structures on or near the turbines. For horizontal axis wind turbines (HAWTs), applying a diffuser has shown to have a beneficial impact on the power production, but it is still under development. For a vertical axis wind turbine (VAWT) it is expected that flow augmentation will also strongly increase the performance of the turbine, but very little research has been done in this field. The purpose of this research is to investigate the effects of a diffuser on the airflow through a VAWT. In order to investigate these effects, the turbine (with and without diffuser) is simulated using a 2-D unsteady free-wake potential-flow panel model. The local flow field, local angles of attack, shed vorticity, the shape and strength of the wake, and the rotor torque are investigated for both the case with and without the diffuser. The diffuser used in this research consists of two mirrored airfoil cross-sections. The size of the duct-opening in which the turbine operates is varied. This work shows that unlike for a 1-D actuator disc analysis, the area ratio B of the diffuser exit with respect to the diffuser nozzle area is not the only driving factor in the augmentation of the rotor torque of the VAWT. More important are the effect of the directional change of the rotor inflow and the faster downstream transport of the shed vorticity.Aerodynamics, Wind Energy & PropulsionAerospace Engineerin

Trust should correspond to Trustworthiness: a Formalization of Appropriate Mutual Trust in Human-Agent Teams

In human-agent teams, how one teammate trusts another teammate should correspond to the latter's actual trustworthiness, creating what we would call appropriate mutual trust. Although this sounds obvious, the notion of appropriate mutual trust for human-agent teamwork lacks a formal definition. In this article, we propose a formalization which represents trust as a belief about trustworthiness. Then, we address mutual trust, and pose that agents can use beliefs about trustworthiness to represent how they trust their human teammates, as well as to reason about how their human teammates trust them. This gives us a formalization with nested beliefs about beliefs of trustworthiness. Next, we highlight that mutual trust should also be appropriate, where we define appropriate trust in an agent as the trust which corresponds directly to that agent's trustworthiness. Finally, we explore how agents can define their own trustworthiness, using the concepts of ability, benevolence and integrity. This formalization of appropriate mutual trust can form the base for developing agents which can promote such trust.Interactive Intelligenc

Experimental and numerical investigation of the 3D VAWT wake

Aerospace Design, Integration and OperationsAerospace Engineerin

Risk sensitivity and theory of mind in human coordination

What humans do when exposed to uncertainty, incomplete information, and a dynamic environment influenced by other agents remains an open scientific challenge with important implications in both science and engineering applications. In these contexts, humans handle social situations by employing elaborate cognitive mechanisms such as theory of mind and risk sensitivity. Here we resort to a novel theoretical model, showing that both mechanisms leverage coordinated behaviors among self-regarding individuals. Particularly, we resort to cumulative prospect theory and level-k recursions to show how biases towards optimism and the capacity of planning ahead significantly increase coordinated, cooperative action. These results suggest that the reason why humans are good at coordination may stem from the fact that we are cognitively biased to do so.Team Sergio Pequit

A 3d unsteady panel method for vertical axis wind turbines

Aerospace Engineerin

Improving Pedestrian Prediction Models with Self-Supervised Continual Learning

Autonomous mobile robots require accurate human motion predictions to safely and efficiently navigate among pedestrians, whose behavior may adapt to environmental changes. This paper introduces a self-supervised continual learning framework to improve data-driven pedestrian prediction models online across various scenarios continuously. In particular, we exploit online streams of pedestrian data, commonly available from the robot's detection and tracking pipelines, to refine the prediction model and its performance in unseen scenarios. To avoid the forgetting of previously learned concepts, a problem known as catastrophic forgetting, our framework includes a regularization loss to penalize changes of model parameters that are important for previous scenarios and retrains on a set of previous examples to retain past knowledge. Experimental results on real and simulation data show that our approach can improve prediction performance in unseen scenarios while retaining knowledge from seen scenarios when compared to naively training the prediction model online.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Learning & Autonomous ControlRobot Dynamic