An algebraic approach to modeling distributed multiphysics problems: The case of a DRI reactor

© 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.This paper deals with the problem of modelling a chemical reactor for the Direct Reduction of Iron ore (DRI). Such a process is being increasingly promoted as a more viable alternative to the classic Blast Furnace for the production of iron from raw minerals. Due to the inherent complexity of the process and the reactor itself, its effective monitoring and control requires advanced mathematical models containing distributed-parameter components. While classical approaches such as Finite Element or Finite Differences are still reasonable options, for accuracy and computational efficiency reasons, an algebraic approach is proposed. A full multi-physical, albeit one-dimensional model is addressed and its accuracy is analysed

Plug-and-Play Fault Detection and control-reconfiguration for a class of nonlinear large-scale constrained systems

This paper deals with a novel Plug-and-Play (PnP) architecture for the control and monitoring of Large-Scale Systems (LSSs). The proposed approach integrates a distributed Model Predictive Control (MPC) strategy with a distributed Fault Detection (FD) architecture and methodology in a PnP framework. The basic concept is to use the FD scheme as an autonomous decision support system: once a fault is detected, the faulty subsystem can be unplugged to avoid the propagation of the fault in the interconnected LSS. Analogously, once the issue has been solved, the disconnected subsystem can be re-plugged-in. PnP design of local controllers and detectors allow these operations to be performed safely, i.e. without spoiling stability and constraint satisfaction for the whole LSS. The PnP distributed MPC is derived for a class of nonlinear LSSs and an integrated PnP distributed FD architecture is proposed. Simulation results in two paradigmatic examples show the effectiveness and the potential of the general methodology

La mente estesa ma individuata: una prospettiva simbiotica

Riassunto: Nell’ambito delle associazioni simbiotiche ha acquisito credito crescente la cosiddetta prospettiva “olobiontica”, secondo cui animali e piante non dovrebbero più essere considerati entità autonome, con confini chiaramente delimitati, ma li si dovrebbe vedere come unità funzionali che consistono di reti inter-relazionali tra specie diverse. In quest’ottica le funzioni precedentemente attribuite a un singolo componente devono essere riviste alla luce della prospettiva relazionale e considerate quindi come prodotto di un’unità funzionale, ossia dell’olobionte. Nella prospettiva funzionalista, il noto concetto di mente estesa considera la possibilità per cui il veicolo della cognizione possa andare oltre il cervello e anche oltre i limiti del corpo, mediante dispositivi artificiali. Questo lavoro intende offrire una variante della teoria della mente estesa intesa non solo come possibilità teoretica ma anche come ipotesi compatibile con alcuni recenti sviluppi nella ricerca biologica e biomedica. Si sosterrà quindi che l’attività del microbiota umano (i batteri che vivono in associazione con le specie umane) svolgono un ruolo funzionale nella regolazione dei nostri processi cognitivi, suggerendo che il microbiota costituisce un’estensione funzionale del sistema cognitivo precedentemente descritto come “umano”. La revisione e l’estensione dell’individuo biologico in favore dell’olobionte come unità funzionale (il vero creatore delle funzioni cognitive) porta anche alla necessità di aggiornare i confini dell’individuo come agente cognitivo.Parole chiave: Microbiota; Cognizione estesa; Olobionte; Simbiosi; Funzionalismo The individuated extended mind: A symbiotic perspective Abstract: In the framework of symbiotic associations, the so-called “holobiontic” perspective has increasingly emerged, according to which animals and plants should no longer be considered as autonomous entities, delimited by clear boundaries, but should rather be seen as functional units, consisting of inter-relational networks of different species. From this perspective, the functions that were previously ascribed to a single component, must be updated in the light of this relational perspective and rather judged as a product of the functional unit, that is, the holobiont. In a functionalist perspective, the famous conception of the extended mind investigates the hypothesis that the vehicle of cognition can extend not only outside the brain but also beyond the limits of the body, through artificial devices. The present work aims to offer a variant of the extended theory of mind not only as a theoretical possibility but also in accordance with some recent developments in biological and biomedical research. It will therefore be argued that the activity of the human microbiota (bacteria living in associations with the human species) plays a functional role in the regulation of our cognitive processes suggesting that the microbiota constitutes a functional extension of the cognitive system previously described as “human”. The revision and extension of the biological individual in favor of the holobiont as a functional unit (therefore the true creator of cognitive functions) also leads to the need to update the boundaries of the individual as a cognitive agent.Keywords: Microbiota; Extended Cognition; Holobiont; Symbiosis; Functionalis

A distributed networked approach for fault detection of large-scale systems

Networked systems present some key new challenges in the development of fault diagnosis architectures. This paper proposes a novel distributed networked fault detection methodology for large-scale interconnected systems. The proposed formulation incorporates a synchronization methodology with a filtering approach in order to reduce the effect of measurement noise and time delays on the fault detection performance. The proposed approach allows the monitoring of multi-rate systems, where asynchronous and delayed measurements are available. This is achieved through the development of a virtual sensor scheme with a model-based re-synchronization algorithm and a delay compensation strategy for distributed fault diagnostic units. The monitoring architecture exploits an adaptive approximator with learning capabilities for handling uncertainties in the interconnection dynamics. A consensus-based estimator with timevarying weights is introduced, for improving fault detectability in the case of variables shared among more than one subsystem. Furthermore, time-varying threshold functions are designed to prevent false-positive alarms. Analytical fault detectability sufficient conditions are derived and extensive simulation results are presented to illustrate the effectiveness of the distributed fault detection technique

Numerical study on the reduction of the seismic vulnerability of historical industrial buildings with wide timber roofs

In the paper are presented the results of a preliminary numerical study concerning the evaluation of the effectiveness of interventions for the reduction of the seismic vulnerability of buildings with traditional multiple sloping timber roofs laid on masonry walls along the building perimeter and on columns internally. In particular, the effects of three different strengthening strategies are analyzed: the bracing of the roof diaphragm by means of wooden-based nailed panels, the addition of steel portal frames and the reinforcement of the masonry through the application of a mortar coating with composite meshes embedded. To take into account the different interventions effects, a simplified numerical procedure, based on non-linear-static analysis, is proposed and a case study is analyzed numerically to compare, in terms of resistant ground acceleration, ag,res, the effects of the different reinforcement techniques. Typically, the absence of the roof diaphragm determines the out-of-plane collapse of the longitudinal walls, for very low seismic actions. The roof stiffening induces a redistribution of the seismic load from the longitudinal walls to the transversal ones; however, as they are not dimensioned for horizontal loads, very modest benefits emerged in terms of ag,res. The addition of two steel portal frames or the reinforcement of the walls with the reinforced mortar technique permits to reach values of the resistant acceleration considerably higher than that of the unreinforced configuration (1.91 and 2.73 times higher, respectively)

Experimental and analytical study to evaluate the effectiveness of an in-plane reinforcement for masonry walls using GFRP meshes

The paper collects the results of diagonal compression tests to compare the in-plane behavior of unreinforced masonry (URM) and of masonry strengthen with a GFRP reinforced mortar coating. Experimental tests concern square wallettes of different masonry types and thickness; different mortars are considered for the coating. Significant increasing both in resistance and ductility emerges in reinforced masonry (RM). The principal tensile strengths are derived from experimental results and an analytical formulation is proposed for the RM resistance prediction. The formulation evidences that the contribution of the reinforced mortar coating is influenced by the characteristics of both the masonry and the reinforcement

Masonry vaults subjected to horizontal loads: Experimental and numerical investigations to evaluate the effectiveness of a GFRM reinforcement

The paper investigates the effectiveness of a modern reinforcement technique based on a Glass Fiber-Reinforced Mortar (GFRM) for the enhancement of the performances of existing masonry vaults subjected to horizontal seismic actions. In fact, the authors recently evidenced, through numerical simulations, that the typical simplified loading patterns generally adopted in the literature for the experimental tests, based on concentrated vertical loads at 1/4 of the span, are not reliable for such a purpose, due to an unrealistic stress distribution. Thus, experimental quasi-static cyclic tests on full-scale masonry vaults based on a specific setup, designed to apply a horizontal load pattern proportional to the mass, were performed. Three samples were tested: an unreinforced vault, a vault reinforced at the extrados and a vault reinforced at the intrados. The experimental results demonstrated the technique effectiveness in both strength and ductility. Moreover, numerical simulations were performed by adopting a simplified FE, smear-crack model, evidencing the good reliability of the prediction by comparison with the experimental results