Plug-and-Play Model Predictive Control based on robust control invariant sets

In this paper we consider a linear system represented by a coupling graph between subsystems and propose a distributed control scheme capable to guarantee asymptotic stability and satisfaction of constraints on system inputs and states. Most importantly, as in Riverso et al., 2012 our design procedure enables plug-and-play (PnP) operations, meaning that (i) the addition or removal of subsystems triggers the design of local controllers associated to successors to the subsystem only and (ii) the synthesis of a local controller for a subsystem requires information only from predecessors of the subsystem and it can be performed using only local computational resources. Our method hinges on local tube MPC controllers based on robust control invariant sets and it advances the PnP design procedure proposed in Riverso et al., 2012 in several directions. Quite notably, using recent results in the computation of robust control invariant sets, we show how critical steps in the design of a local controller can be solved through linear programming. Finally, an application of the proposed control design procedure to frequency control in power networks is presented

Secure Cloud-Edge Deployments, with Trust

Assessing the security level of IoT applications to be deployed to heterogeneous Cloud-Edge infrastructures operated by different providers is a non-trivial task. In this article, we present a methodology that permits to express security requirements for IoT applications, as well as infrastructure security capabilities, in a simple and declarative manner, and to automatically obtain an explainable assessment of the security level of the possible application deployments. The methodology also considers the impact of trust relations among different stakeholders using or managing Cloud-Edge infrastructures. A lifelike example is used to showcase the prototyped implementation of the methodology

Modelling and Multi-stage Design of Membrane Processes Applied to Carbon Capture in Coal-fired Power Plants

AbstractAccording to recent predictions, energy generation from coal will continue to play a key role in the next decades. The UK 2008 Climate Change Act requires a reduction of 80% of greenhouse gases emissions by 2050, and carbon capture and storage will have a key role in order to meet this target.This work focuses on post-combustion capture from coal-fired power plants based on membrane separation. Adetailed multi-stage design is presented: the developed flowsheet includes cross-flow and countercurrent-sweep stages. The cross-flow stages are based on a 2D model implemented by our research group able to predict the separation through spiral-wound permeators. Different process configurations are analysed, with the aim of reducing both energy consumption and membrane area.An economic analysis is also included: both capture and avoidance costs are evaluated. The estimated values are compared with data available in the literature for processes based on amine capture technology

Plug-and-Play Decentralized Model Predictive Control

In this paper we consider a linear system structured into physically coupled subsystems and propose a decentralized control scheme capable to guarantee asymptotic stability and satisfaction of constraints on system inputs and states. The design procedure is totally decentralized, since the synthesis of a local controller uses only information on a subsystem and its neighbors, i.e. subsystems coupled to it. We first derive tests for checking if a subsystem can be plugged into (or unplugged from) an existing plant without spoiling overall stability and constraint satisfaction. When this is possible, we show how to automatize the design of local controllers so that it can be carried out in parallel by smart actuators equipped with computational resources and capable to exchange information with neighboring subsystems. In particular, local controllers exploit tube-based Model Predictive Control (MPC) in order to guarantee robustness with respect to physical coupling among subsystems. Finally, an application of the proposed control design procedure to frequency control in power networks is presented.Comment: arXiv admin note: text overlap with arXiv:1210.692

Voltage stabilization in DC microgrids: an approach based on line-independent plug-and-play controllers

We consider the problem of stabilizing voltages in DC microGrids (mGs) given by the interconnection of Distributed Generation Units (DGUs), power lines and loads. We propose a decentralized control architecture where the primary controller of each DGU can be designed in a Plug-and-Play (PnP) fashion, allowing the seamless addition of new DGUs. Differently from several other approaches to primary control, local design is independent of the parameters of power lines. Moreover, differently from the PnP control scheme in [1], the plug-in of a DGU does not require to update controllers of neighboring DGUs. Local control design is cast into a Linear Matrix Inequality (LMI) problem that, if unfeasible, allows one to deny plug-in requests that might be dangerous for mG stability. The proof of closed-loop stability of voltages exploits structured Lyapunov functions, the LaSalle invariance theorem and properties of graph Laplacians. Theoretical results are backed up by simulations in PSCAD

Il perturbante dello specchio e l'autoritratto

Il testo di Stefano Ferrari dal titolo "Il perturbante dello specchio e l'autoritratto" fa parte di "Nel cuore della meraviglia" [Atti del convegno, marzo 2000] a cura di Isabelle Mallez e Raffaele Milani, "Quaderni di PsicoArt", n. 1, 2010

Alcune riflessioni su Outsider Art e psicologia dell'arte

Il testo ha una carattere prevalentemente teorico e metodologico e intende mettere in evidenza i punti i di contatto tra la variegata realtà delle Outsider art e quella non meno ampia e problematica della psicologia dell’arte. Tra i problemi che vengono affrontati segnaliamo quello della definizione del concetto e dell’ambito di outsider art, quello delle relazioni tra questo tipo di produzioni e l’arte contemporanea, quello dei rapporti tra arte, vita e malattia, quello del contesto in cui valorizzare questo tipo di produzioni Some thoughts on the psychology of art and Outsider Art The text has a predominantly theoretical and methodological dimension and intends to highlight the points of contact between the diverse reality of Outsider Art and the equally large problem of the Psychology of art. Among the issues analyzed there are the definition of the concept and the aim of outsider art, the relationship between this type of productions and contemporary art, the relationship among art, life and disease, the context in which it is more appropriate to value this type of productions

Bellezza e sessualità a partire da Freud

Partendo da una citazione di Freud tratta dal Disagio della civilt\ue0 (1929) in cui il carattere della bellezza viene esplicitamente associato alla sfera della sessualit\ue0, il saggio si sofferma sul concetto di sublimazione, soprattutto per quanto riguarda le arti visive, intese dalla psicoanalisi classica come settore di riferimento della pulsione scopofilia. Al di l\ue0 di facili e schematiche approssimazioni, vengono poi analizzati alcuni motivi iconografici in cui questa dimensione \ue8 pi\uf9 evidente. Tra questi la rappresentazione di Tarquinio e Lucrezia (Tintoretto e Cranach), Susanna e i vecchioni (Tintoretto, Rubens, Reni, Allori) e il mito di Medusa (Caravaggio, Rubens Courbet)