Centre of Technology and Systems

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Publications

An Evolution Model for Remote and Virtual Labs

Publication . Correia, Raul Cordeiro; Alves, Gustavo R.; Fonseca, José Manuel

A graphical model that describes and anticipates the evolution of remote and virtual laboratory systems and networks is proposed. eThe model was built considering the “remote past” and the “recent past”, to make a projection about the future evolution, on each of the development lines that persist today. The verification of the proposed model considers some remote and virtual labs networks and systems that have existed and/or still exist today translating their story through graphs that show the evolution of the system affected by different variables, states, flows, processes, and results defined on the dynamic model and also a specific sub-model for the kernel of the main model.

2021Conference object

Restricted access

Revisiting the 1D and 2D Laplace Transforms

Publication . Duarte Ortigueira, Manuel; Machado, J. A. Tenreiro

The paper reviews the unilateral and bilateral, one- and two-dimensional Laplace transforms. The unilateral and bilateral Laplace transforms are compared in the one-dimensional case, leading to the formulation of the initial-condition theorem. This problem is solved with all generality in the one- and two-dimensional cases with the bilateral Laplace transform. The case of fractional-order systems is also included. General two-dimensional linear systems are introduced and the corresponding transfer function is defined

2020Journal article

Open access

New discrete-time fractional derivatives based on the bilinear transformation: Definitions and properties

Publication . Ortigueira, Manuel D.; Machado, J. A. Tenreiro

In this paper we introduce new discrete-time derivative concepts based on the bilinear (Tustin) transformation. From the new formulation, we obtain derivatives that exhibit a high degree of similarity with the continuous-time Grünwald-Letnikov derivatives. Their properties are described highlighting one important feature, namely that such derivatives have always long memory.

2020Journal article

Open access