Encontrados 8 documentos, a visualizar página 1 de 1

PROTECÇÃO DO CIBERESPAÇO: VISÃO ANALÍTICA

Vários factores têm contribuído para destacar na agenda política dos Estados a protecção do ciberespaço. Por um lado assistimos a um desenvolvimento acelerado da sociedade da informação e a uma crescente dependência das TIC em praticamente todas as funções vitais do funcionamento de infra-estruturas críticas nacionais. Por outro, este “mundo em rede” desenvolveu um novo plano de condução de conflitos com caract...

Avaliação do ciclo de vida e custeio do ciclo de vida de evaporadores para usin...

As usinas de açúcar no Brasil utilizam aço-carbono, um material de baixo custo, mas com pequena resistência à corrosão. Os aços inoxidáveis são os materiais mais adequados para a sua substituição, entretanto eles são considerados caros. Foi realizada a avaliação ambiental e financeira de tubos para evaporadores de usinas de açúcar construídos em aço-carbono e, comparativamente, com os aços inoxidáveis do tipo A...

Optimal sizing, scheduling and shift policy of the grinding section of a cerami...

This paper addresses the optimal design of the grinding section of a ceramic tile plant operating in a cyclic mode with the units (mills) following a batch sequence. The optimal design problem of this single product plant is formulated with a fixed time horizon of one week, corresponding to one cycle of production, and using a discrete-time resource task network (RTN) process representation. The size of the ind...

A tool to analyze robust stability for constrained nonlinear MPC

A sufficient condition for robust asymptotic stability of nonlinear constrained model predictive control (MPC) is derived with respect to plant/model mismatch. This work is an extension of a previous study on the unconstrained nonlinear MPC problem, and is based on nonlinear programming sensitivity concepts. It addresses the discrete time state feedback problem with all states measured. A strategy to estimate b...

Unscented Kalman Filtering of a Simulated pH System

Recently, the unscented Kalman filter (UKF) algorithm, which is a new generalization of the Kalman filter for nonlinear systems, was proposed in the literature. It has significant advantages over its widely used predecessor, the extended Kalman filter (EKF). These include better accuracy and simpler implementation and the dispensability of system and measurement model differentiability. In this work, we compare...

On-line implementation of nonlinear MPC: an experimental case study

A nonlinear model predictive control algorithm is implemented on-line to control the liquid level and temperature in a pilot plant CSTR, where an irreversible exothermic chemical reaction is simulated experimentally by steam injection. The dynamic behavior of the pilot plant reactor is represented using a mechanistic, first principle model and a comparison between off-line simulation and experimental data is pr...

A tool to analyze robust stability for model predictive controllers

A strategy based on Nonlinear Programming (NLP) sensitivity is developed to establish stability bounds on the plant/model mismatch for a class of optimization-based Model Predictive Control (MPC) algorithms. By extending well-known nominal stability properties for these controllers, we derive a sufficient condition for robust stability of these controllers. This condition can also be used to assess the extent o...

Os Iodetos nas affecções das vias respiratórias