Encontrados 14 documentos, a visualizar página 1 de 2
Efficient Optimization Algorithm for Space-Variant Mixture of Vector Fields
Nascimento, Jacinto C.; Barão, Miguel; Marques, Jorge S.; Lemos, João M.This paper presents a new algorithm for trajectory classifi- cation of human activities. The presented framework uses a mixture of parametric space-variant vector fields to describe pedestrian’s trajecto- ries. An advantage of the proposed method is that the vector fields are not constant and depend on the pedestrian’s localization. This means that the switching motion among vector fields may occur at any image...
Interactive Air Traffic Control automation in oceanic airspace
Freitas, Francisco; Barão, Miguel; Ventura, RodrigoAir traffic controllers workload limits impose upper bounds to the amount of traffic manageable in a given air sector for a given time frame. Air Traf- fic Control (ATC) automation methods open the possibility of reducing this workload by shifting to the machine the tasks of (1) detecting poten- tial conflicts, and of (2) proposing to the controller ATC instructions that prevent such conflicts. We propose a dec...
An algorithm for cooperative probabilistic control design
Barão, MiguelThis paper deals with the decentralized closed loop control in a pure probabilistic framework. In this framework, a system is a controlled Markov chain whose transition probabilities depend on the actions of the agents. The agents are also described in a probabilistic way. The objective is to drive the system so that the joint state and agents actions are close to a set of given target probability distributions...
Recursive bayesian identification of nonlinear autonomous systems
Simão, Tiago; Barão, Miguel; Marques, Jorge S.This paper concerns the recursive identification of nonlinear discrete-time systems for which the original equations of motion are not known. Since the true model structure is not available, we replace it with a generic nonlinear model. This generic model discretizes the state space into a finite grid and associates a set of velocity vectors to the nodes of the grid. The velocity vectors are then interpolated t...
Alignment of velocity fields for video surveillance
Marques, Jorge S.; Barão, Miguel; Lemos, João M.Velocity fields play an important role in surveillance since they describe typical motion behaviors of video objects (e.g., pedestrians) in the scene. This paper presents an algorithm for the alignment of velocity fields acquired by different cameras, at different time intervals, from different viewpoints. Velocity fields are aligned using a warping function which maps corresponding points and vectors in both f...
Alignment of velocity fields for video surveillance
Marques, Jorge S.; Barão, Miguel; Lemos, João M.Velocity fields play an important role in surveillance since they describe typical motion behaviors of video objects (e.g., pedestrians) in the scene. This paper presents an algorithm for the alignment of velocity fields acquired by different cameras, at different time intervals, from different viewpoints. Velocity fields are aligned using a warping function which maps corresponding points and vectors in both f...
A control Lyapunov function approach to Adaptive Control of HIV-1 Infection
Lemos, João M.; Barão, Miguel José SimõesThis paper presents an algorithm for nonlinear adaptive control of the viral load in HIV-1 infection. The infection model considered is a reduced complexity nonlinear state-space model with two state variables, that represent the plasma concentration of uninfected and infected CD4+ T-cells of the human immune system. The viral load is assumed to be proportional to the concentration of infected cells. First, a c...
Optimal Control for Vehicle Cruise Speed Transfer
Jorge, Tiago R.; Lemos, João M.; Barão, MiguelThe contribution of this paper consists in a procedure to solve the optimal cruise control problem that consists in transferring the car velocity between two specified values, in a fixed interval of time, with minimum fuel consumption. The solution is obtained by applying a recursive numerical algorithm that provides an approximation to the condition provided by Pontryagin’s Optimum Principle. This solution is ...
Offline Bayesian Identification of Jump Markov Nonlinear Systems
Barão, Miguel; Marques, Jorge S.This paper presents a framework for the offline identification of nonlinear switched systems with unknown model structure. Given a set of sampled trajectories, and under the assumption that they were generated by switching among a number of models, we estimate a set of vector fields and a stochastic switching mechanism that best describes the observed data. The switching mechanism is described by a position dep...
Hybrid Dynamic Optimization for Cruise Speed Control
Jorge, Tiago R.; Lemos, João M.; Barão, Miguel; Bemporad, AlbertoThe cruise control problem of transferring the speed of a vehicle between two values in a fixed interval of time using a predefined sequence of gears is solved in this paper. This is a hybrid dynamic optimization problem since the control variables include both a continuous variable (fuel flow) and a discrete variable (the gear to apply at each instant). The solution is given in the form of a hybrid optimal con...
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