34 documents found, page 1 of 4
Monitorização Quadrienal de Nitratos nos Recursos Hídricos Subterrâneos da Zona...
Leitão, Bruno; Nogueira, Abel; Silva, Afonso; Brás, Alda; Duarte, António; Vicente, Ana; Peixoto, André; Matos, António; Miranda, FernandoO Conselho das Comunidades Europeias em 1991, através da Diretiva 91/676/CEE de 12 de dezembro de 1991, reconheceu a importância de proteger as áreas de elevada suscetibilidade para a poluição das águas, causada ou induzida por nitratos (NO3-) de origem agrícola. Uma dessas áreas é a Zona Vulnerável a Nitratos (ZVN) de Esposende -Vila do Conde, criada em 1997 pela Portaria n.º 1037/1997 de 1 de outubro, à data ...
Oracle for guidance with deep neural networks in reusable launch vehicle landing
Igreja, José; Lemos, Joao MOracles are of paramount importance for Deep Neural Networks training. In this paper, an oracle developed for landing reusable launch vehicles is created from a linearizing feedback control law that can perform a prescribed landing trajectory tracking. The oracle is then used to train a Deep Neural Network that can be used as a guidance system for landing maneuvers. Verification is performed by Monte-Carlo.
Soft flocks for rendezvous and pursuit missions with distributed MPC
Igreja, José; Lemos, J. M.This paper concerns of MPC (Model Predictive Control) solutions for self-organized or soft flock formations of agents while carrying out an assigned mission. A distributed MPC algorithm is proposed to solve the formulated problem. Pursuit missions by agents formations can also be treated with the exact same algorithm. The obtained solution is completely decentralized in terms of pathfinding and mission completi...
Analysis and loop-shaping of holomorphic dynamical PDE systems
Igreja, José; Lemos, J. M.Holomorphic Dynamical systems is a class of infinite dimensional systems with a infinite number of zeros and no poles. Systems in this class are always BIBO stable with an exact finite settling time for the step response, because they are in feedforward mode, without any inherent feedback physical mechanism. In this paper a precise definition of Holomorphic Dynamical systems is given along with a stability resu...
Wind Energy Conversion System under a Supervisor Deterministic Finite State Mac...
Viveiros, Carla; Melício, Rui; Igreja, José; Mendes, VictorThis paper presents a simulation of an onshore energy conversion system connected to the electric grid and under a strategy of a supervisor control based on deterministic version of a finite state machine. The simulation is planned to address an analysis on performance due to the action of the supervisor. The supervisor is included at the higher level, having the objective of analyzing the operational states ac...
Energy management in buildings with intermittent and limited renewable resources
Barata, Filipe; Igreja, JoséThis work reports a contribution, in a model predictive control multi-agent systems context, introducing a novel integrative methodology to manage energy networks from the demand-side point of view, in the strong presence of intermittent energy sources, including energy storage in households or car batteries. In particular, the article presents a control-based solution for indoor comfort, which, in addition, op...
Robust control of a Thermal Unstable PDE system
Igreja, José; Lemos, João M.Some distributed parameter systems with irrational transfer function can be written into an infinite factorized quotient for dynamic analysis and control design purposes. Hence, high accuracy approximate time solutions and frequency uncertainty bounds can be computed exactly, enabling early lumping in robust controller design. In this paper the focus is on finding a block factorization for a thermal unstable so...
Finite dimensional models of the hydraulic hammer effect and solar tower control
Igreja, José; Marakkos, Costas; Lemos, JoãoThe occurrence of traveling shock waves associated to the sudden opening or closing of a valve, known as the hammer effect, is important from the perspective of control design because it imposes an upper bound constraint on the maximum bandwidth achievable for the controlled system. This article addresses the problem of characterizing hydraulic hammer effect of the heating fluid in a solar power tower. The tran...
Adaptive and predictive controllers applied to onshore wind energy conversion s...
Viveiros, Carla; Melicio, Rui; Mendes, Victor; Igreja, JoséThis paper presents a simulation of onshore energy conversion system connected to the electric grid and under an event-based supervisor control based on deterministic version of a finite state machine. The onshore energy conversion system is composed by a variable speed wind turbine, a mechanical transmission system described by a two-mass drive train, a gearbox, a doubly fed induction generator rotor and by a ...
Control and Supervision of Wind Energy Conversion Systems
Viveiros, Carla; Melício, Rui; Igreja, José; Mendes, VictorThis paper is about a PhD thesis and includes the study and analysis of the performance of an onshore wind energy conversion system. First, mathematical models of a variable speed wind turbine with pitch control are studied, followed by the study of different controller types such as integer-order controllers, fractional-order controllers, fuzzy logic controllers, adaptive controllers and predictive controllers...