Miguel Aguiar's research while affiliated with KTH Royal Institute of Technology and other places

Publications (15)

Preprint
Full-text available
We consider the problem of approximating flow functions of continuous-time dynamical systems with inputs. It is well-known that continuous-time recurrent neural networks are universal approximators of this type of system. In this paper, we prove that an architecture based on discrete-time recurrent neural networks universally approximates flows of...
Preprint
Full-text available
We describe a recurrent neural network (RNN) based architecture to learn the flow function of a causal, time-invariant and continuous-time control system from trajectory data. By restricting the class of control inputs to piecewise constant functions, we show that learning the flow function is equivalent to learning the input-to-state map of a disc...
Conference Paper
Full-text available
Marine pollution incidents can have a huge impact on different ecosystems, with unpredictable short- and long-term consequences. Once the pollutant is detected, it is critical to quickly understand its characteristics so that authorities can lay out an adequate response. In parallel to the time- and cost-constrained traditional operational means, t...
Preprint
Full-text available
div>The REP(MUS)19 is an exercise that takes place annually since 2010 in the south of continental Portugal. LSTS (Underwater Systems and Technology Laboratory) has co-organized these events, since the beginning, together with the Portuguese Navy and, in more recent years, with NATO-CMRE. NATO’s MUS (Maritime Unmanned Systems Initiative) initiativ...
Preprint
div>The REP(MUS)19 is an exercise that takes place annually since 2010 in the south of continental Portugal. LSTS (Underwater Systems and Technology Laboratory) has co-organized these events, since the beginning, together with the Portuguese Navy and, in more recent years, with NATO-CMRE. NATO’s MUS (Maritime Unmanned Systems Initiative) initiativ...
Preprint
Full-text available
This paper deals with traffic density reconstruction using measurements from Probe Vehicles (PVs). The main difficulty arises when considering a low penetration rate, meaning that the number of PVs is small compared to the total number of vehicles on the road. Moreover, the formulation assumes noisy measurements and a partially unknown first-order...
Article
General problems of optimal trajectory generation and of optimal space-time rendezvous for autonomous underwater vehicles affected by time-varying fluid flows are formulated and solved in the framework of dynamic programming. The optimal solutions include optimal trajectories, as well as departure times and positions. The approach consists in using...
Conference Paper
Full-text available
We consider the problem of generating optimal planar trajectories for marine vehicles taking into account the effect of time-varying ocean currents. This is motivated by the need for economic trajectory generation in long-duration operations, and it becomes even more important in scenarios where the magnitude of the ocean current speed is comparabl...

Citations

... For that reason, an area anomaly analysis was carried out by subtracting the sea outfall daily area of the respective month from the monthly sea outfall average area. Nevertheless, to comprehend the influence of the local meteo-oceanographic conditions on the outfall turbid plume's dispersion, sea surface elevation data were acquired for the Aveiro lagoon mouth from an existing hydrodynamic model [38], and hourly wind speed and direction were acquired from a WRF model (the Weather Research and Forecasting (WRF) Model is a mesoscale numerical weather prediction system used for atmospheric research and operational forecasting applications), with a spatial resolution of 12 km [39]. For this reason, one example of the wastewater plume dispersing inward toward the Ria de Aveiro coastal lagoon, observed through ocean color data, will be addressed. ...
... The paradigm of physics-informed deep learning [13][14], which integrates the dual advantages of model driven model and data driven model, has received increasing attention since its introduction in recent years, and has also sparked a research wave in transportation fields such as traffic state estimation (TSE) [15][16]. Combining the basic laws of traffic flow and deep learning methods, such as Lighthill-Whitham-Richards (LWR) model and ANN model, PIDL can accurately and timely estimated traffic state utilizing limited and noisy sparse data [17][18]. ...
... A 3D implementation was established for the Sado estuary by applying the FLOW module and, for the first time, the WAQ module of the numerical model Delft3D (Deltares, 2021(Deltares, , 2014. A structured (curvilinear) spherical grid was generated based on the applications developed by Aguiar et al. (2020) and Ribeiro et al. (2016). The main differences to the previous implementations are the increase of the grid resolution (from ∼1500 m to ∼300 m on average in the offshore region and from ∼100 m to ∼80 m in the estuary body) and the inclusion of the intertidal areas in the grid. ...
... Many authors have proposed interesting controllers or observers such as [1][2][3][4][5][6][7][8][9]; however, in most of the studies, the robot models are assumed to be controllable or observable without any proof. A method to determine the controllability of a robot model is important because a robot model that is assured to be controllable can guarantee the existence of a controller to reach one of the objectives such as regulation, tracking, disturbance rejection, etc. ...
... Critically, our efforts are in the open ocean, well beyond the confines of the coastal zone, where there was no guarantee of being able to find the STF frontal zone. Equally, our work involves a rich legacy of software infrastructure used across multiple field experiments (Das et al., 2011;Faria et al., 2014b;de Sousa et al., 2016a;Py et al., 2016;de Sousa et al., 2016b;Chrpa et al., 2017;Fossum et al., 2018;Ferreira et al., 2019;Costa et al., 2018;Dias et al., 2020), and not a bespoke method, emphasizes propelled vehicles with substantial payload and computational abilities which makes for adaptations in situ. ...
... This work builds upon the results in Aguiar et al. [1], who presented an efficient method and implementation for computing time-optimal trajectories for AUVs using high-resolution water velocity models. Using the LSTS -Underwater Systems and Technology Laboratory -software toolchain [2], we incorporate the method into a networked vehicle system, optimizing vehicle deployments and enabling the operationalization of marine pollution incident in situ verification. ...
... Many authors have proposed interesting controllers or observers such as [1][2][3][4][5][6][7][8][9]; however, in most of the studies, the robot models are assumed to be controllable or observable without any proof. A method to determine the controllability of a robot model is important because a robot model that is assured to be controllable can guarantee the existence of a controller to reach one of the objectives such as regulation, tracking, disturbance rejection, etc. ...