24 documents found, page 1 of 3
Optimized planning of different crops in a field using optimal control in Portugal
Pereira, Rui M. S.; Lopes, Sofia Oliveira; Caldeira, Amélia; Fonte, VictorClimate change is a proven fact. In the report of 2007 from IPCC, one can read that global warming is an issue to be dealt with urgently. In many parts of the world, the estimated rise of temperature (in a very near future) is significant. One of the most affected regions is the Iberian Peninsula, where the increasing need for water will very soon be a problem. Therefore, it is necessary that decision makers ar...
Optimal control for an irrigation problem with several fields and common reservoir
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.In a previous study, the authors developed the planning of the water used in the irrigation systems of a given farmland in order to ensure that the eld cultivation is in a good state of preservation. In this paper, we introduce a model to minimize the water owing into a reservoir that supplies di erent elds with di erent types of crops. This model is described as an optimal control problem where the water ow fr...
Optimal control of a multi-field irrigation problem: validation of a numerical ...
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.In this paper, we address the problem of minimizing the total water consumption over the period of a year used to supply different fields with different types of crops.We start by recalling a previous study, where the authors developed an optimal control model for this problem by minimizing the water flowing into a reservoir and where the water from the precipitation can be collected. The numerical solution obt...
Tau deletion prevents stress-induced dendritic atrophy in prefrontal cortex: ro...
Lopes, Sofia Oliveira; Teplytska, Larysa; Silva, João Luís Vaz Lima da; Dioli, Chrysoula; Trindade, Rita; Morais, Mónica; Webhofer, ChristianTau protein in dendrites and synapses has been recently implicated in synaptic degeneration and neuronal malfunction. Chronic stress, awell-known inducer of neuronal/synaptic atrophy, triggers hyperphosphorylation of Tau protein and cognitive deficits. However, the cause–effect relationship between these events remains to be established. To test the involvement of Tau in stress-induced impairments of cognition,...
Optimal control applied to an irrigation planning problem
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.; Pereira, Rui M. S.; de Pinho, MdR; Gonçalves, A. ManuelaWe propose a mathematical model to study the water usage for the irrigation of given farmland to guarantee that the field crop is kept in a good state of preservation. This problem is formulated as an optimal control problem.The lack of analytic solution leads us to turn to numericalmethods to solve the problem numerically.We then apply necessary conditions of optimality to validate the numerical solution. To d...
Absence of Tau triggers age-dependent sciatic nerve morphofunctional deficits a...
Lopes, Sofia Oliveira; Lopes, André Teixeira; Pinto, Vítor Manuel Silva; Guimarães, Marco Rafael; Sardinha, Vanessa Alexandra Morais; Silva, Sara DuarteDementia is the cardinal feature of Alzheimer's disease (AD), yet the clinical symptoms of this disorder also include a marked loss of motor function. Tau abnormal hyperphosphorylation and malfunction are well-established key events in AD neuropathology but the impact of the loss of normal Tau function in neuronal degeneration and subsequent behavioral deficits is still debated. While Tau reduction has been inc...
Optimal control for an irrigation planning problem: characterisation of solutio...
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.; Pereira, Rui M. S.; Pinho, Maria do Rosário de; Ribeiro, CarolinaIn a previous study, the authors developed the planning of the water used in the irrigation systems of a given farmland in order to ensure that the field cultivation is in a good state of preservation. This planning was modelled and tackled as an optimal control problem: minimize the water flow (control) so that the extent water amount in the soil (trajectory) fulfils the cultivation water requirements. In this...
Optimal control of the irrigation problem : characterization of the solution
Lopes, Sofia Oliveira; Pereira, Rui M. S.; Fontes, Fernando A. C. C.; Pinho, Maria do Rosário de; Machado, Gaspar J.This article studies the optimal solution to the irrigation problem described as: minimize the water flow (control) so that the extent water amount in the soil (trajectory) fulfills the cultivation water requirements. We characterize the solution applying the necessary conditions of optimality in the form of the Maximum Principle. We also compare the results obtained analytically and numerically.
Irrigation planning: an optimal control approach
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.; Pereira, Rui M. S.; Gonçalves, A. Manuela; Machado, Gaspar J.We aim to plan the water usage in the irrigation of a given farmland keeping, at same time, the field cultivation in a good state of preservation. This problem is modeled and tackled as an optimal control problem: minimize the water flow (control) so that the extent water amount in the soil (trajectory) fulfills the cultivation water requirements. To estimate rainfall, we consider two models: one based on the a...
An integral-type constraint qualification to guarantee nondegeneracy of the max...
Lopes, Sofia Oliveira; Fontes, Fernando A. C. C.; Pinho, Maria do Rosário deFor optimal control problems involving ordinary differential equations and functional inequality state constraints, the maximum principle may degenerate, producing no useful information about minimizers. This is known as the degeneracy phenomenon. Several non-degenerate forms of the maximum principle, valid under different constraint qualifications, have been proposed in the literature. In this paper we propose...