1,652 research outputs found

    A theory of the infinite horizon LQ-problem for composite systems of PDEs with boundary control

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    We study the infinite horizon Linear-Quadratic problem and the associated algebraic Riccati equations for systems with unbounded control actions. The operator-theoretic context is motivated by composite systems of Partial Differential Equations (PDE) with boundary or point control. Specific focus is placed on systems of coupled hyperbolic/parabolic PDE with an overall `predominant' hyperbolic character, such as, e.g., some models for thermoelastic or fluid-structure interactions. While unbounded control actions lead to Riccati equations with unbounded (operator) coefficients, unlike the parabolic case solvability of these equations becomes a major issue, owing to the lack of sufficient regularity of the solutions to the composite dynamics. In the present case, even the more general theory appealing to estimates of the singularity displayed by the kernel which occurs in the integral representation of the solution to the control system fails. A novel framework which embodies possible hyperbolic components of the dynamics has been introduced by the authors in 2005, and a full theory of the LQ-problem on a finite time horizon has been developed. The present paper provides the infinite time horizon theory, culminating in well-posedness of the corresponding (algebraic) Riccati equations. New technical challenges are encountered and new tools are needed, especially in order to pinpoint the differentiability of the optimal solution. The theory is illustrated by means of a boundary control problem arising in thermoelasticity.Comment: 50 pages, submitte

    Analisi della vulnerabilita sismica della scuola elementare di Filetto nel Comune di Villafranca in Lunigiana

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    La presente tesi di laurea nasce dalla Convenzione Quadro stipulata tra il Coordinamento Regionale Prevenzione Sismica della Regione Toscana, il Comune di Villafranca in Lunigiana e il Dipartimento di Ingegneria Civile dell’Università di Pisa. Tale Convenzione mira a promuovere le valutazioni preliminari sull’effettivo grado di sicurezza nei confronti dell’azione sismica di edifici “strategici”, fornendo utili informazioni alle amministrazioni pubbliche relativamente all’urgenza di un eventuale intervento ed alle possibili metodologie di miglioramento o adeguamento. L’oggetto della presente tesi è quindi l’analisi della vulnerabilità di un edificio pubblico realizzato in muratura portante: la scuola elementare di Filetto, sita nel Comune di Villafranca in Lunigiana (MS). A fronte di un dettagliato rilievo geometrico strutturale e di estesi saggi in situ volti ad ottenere un adeguato livello di conoscenza del fabbricato, si è resa possibile la realizzazione di un modello numerico, effettuato tramite software di calcolo agli elementi finiti, rappresentativo dell’attuale stato di fatto dell’edificio. In base a quanto previsto dalle NTC 2008 è stata effettuata un’analisi dinamica modale con spettro di risposta in accelerazione; quindi sono state effettuate le verifiche di sicurezza previste sia nel caso di carichi statici che sismici, da cui è stato possibile calcolare l’indice di rischio sismico della struttura e valutare quali sono gli elementi di criticità della stessa. A completamento della valutazione di vulnerabilità sismica è stata effettuata, su un secondo modello numerico, un analisi statica non lineare (push-over) che ha permesso di studiare l’evoluzione in campo plastico della struttura e di valutare il fattore di struttura q (rappresentativo delle risorse post-elastiche della struttura stessa) paragonandolo ai valori previsti dalla Norma vigente per la specifica tipologia strutturale

    Fiscal Reforms during Fiscal Consolidation: The Case of Italy

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    In this paper we aim to discuss the strengths and weaknesses of the fiscal consolidation package adopted recently by the Italian Government in order to achieve a balanced budget by 2013. Revenues are forecasted to increase by more than 3.3 GDP percentage points; these stem mostly from indirect and property taxation. The analysis of the Italian case is interesting since it seems to be consistent with a recent strand of the literature which, in order to foster both short and long-term economic growth, advocated a shift of the tax burden from capital and labour income to consumption and property. Through a set of micro simulation models, this paper evaluates the effects of the Italian fiscal package on households and firms. We show that, in respect of households’ income, indirect and property tax reforms are highly regressive, whilst the reform makes limited resources available for growth enhancing policies (reduction in the effective corporate tax burden). Then, we propose an alternative fiscal package. We show that a less regressive reform on households can be obtained by shifting taxation from personal and corporate income tax to indirect taxation. Our proposal allows the tax burden on firms to be reduced substantially and, in the meantime, offers lower personal income tax rates on households in the lowest deciles of income distribution since they are penalized most by the increase in indirect taxation.tax reforms, fiscal consolidation, micro simulation models, Italy

    Fiscal Reforms during Fiscal Consolidation: The Case of Italy

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    In this paper we aim to discuss the strengths and weaknesses of the fiscal consolidation package adopted recently by the Italian Government in order to achieve a balanced budget by 2013. Revenues are forecasted to increase by more than 3.3 GDP percentage points; these stem mostly from indirect and property taxation. The analysis of the Italian case is interesting since it seems to be consistent with a recent strand of the literature which, in order to foster both short and long-term economic growth, advocated a shift of the tax burden from capital and labour income to consumption and property. Through a set of micro simulation models, this paper evaluates the effects of the Italian fiscal package on households and firms. We show that, in respect of households’ income, indirect and property tax reforms are highly regressive, whilst the reform makes limited resources available for growth enhancing policies (reduction in the effective corporate tax burden). Then, we propose an alternative fiscal package. We show that a less regressive reform on households can be obtained by shifting taxation from personal and corporate income tax to indirect taxation. Our proposal allows the tax burden on firms to be reduced substantially and, in the meantime, offers lower personal income tax rates on households in the lowest deciles of income distribution since they are penalized most by the increase in indirect taxation.Tax reforms, Fiscal consolidation, Micro simulation models, Italy

    Effect of orthopedic and functional orthodontic treatment in children with obstructive sleep apnea: A systematic review and meta-analysis

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    : Orthodontic treatment is suggested in growing individuals to correct transverse maxillary deficiency and mandibular retrusion. Since, as a secondary effect, these orthodontic procedures may improve pediatric obstructive sleep apnea (OSA), this systematic review assessed their effects on apnea-hypopnea index (AHI) and oxygen saturation (SaO2). Twenty-five (25) manuscripts were included for qualitative synthesis, 19 were selected for quantitative synthesis. Five interventions were analyzed: rapid maxillary expansion (RME, 15 studies), mandibular advancement (MAA, five studies), myofunctional therapy (MT, four studies), and RME combined with MAA (one study). RME produced a significant AHI reduction and minimum SaO2 increase immediately after active treatment, at six and 12 months from baseline. A significant AHI reduction was also observed six and 12 months after the beginning of MAA treatment. MT showed positive effects, with different protocols. In this systematic review and meta-analysis of data from mainly uncontrolled studies, interceptive orthodontic treatments showed overall favorable effects on respiratory outcomes in pediatric OSA. However, due to the low to very low level of the body evidence, this treatment cannot be suggested as elective for OSA treatment. An orthodontic indication is needed to support this therapy and a careful monitoring is required to ensure positive improvement in OSA parameters

    Interpretation of Modern Art Masterpieces: No Motor Reflection

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    The article is an experiment that deals with "Embodied Simulation" and " Embodied Cognition". This work follows the procedures of studies of the Parma Group and against them try to demonstrate their failure. The cognition is not embodied at all, maybe a little and at least

    Colours, brain and immateriality

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    The hypothesis we present in this paper is about the representation of colours in the nervous system as metaphysical and immaterial properties of the neural activations, first in the lateral geniculate body and following in the primary visual cortex, where the colours are not directly coded but whose representation is modulated by a signal born by fewer neurons. The metaphysical background of this hypothesis is the dualism of properties that will be discussed in the last paragraph of this article

    Radon mitigation during the installation of the CUORE 0νββ0\nu\beta\beta decay detector

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    CUORE - the Cryogenic Underground Observatory for Rare Events - is an experiment searching for the neutrinoless double-beta (0νββ0\nu\beta\beta) decay of 130^{130}Te with an array of 988 TeO2_2 crystals operated as bolometers at ∼\sim10 mK in a large dilution refrigerator. With this detector, we aim for a 130^{130}Te 0νββ0\nu\beta\beta decay half-life sensitivity of 9×10259\times10^{25} y with 5 y of live time, and a background index of ≲10−2\lesssim 10^{-2} counts/keV/kg/y. Making an effort to maintain radiopurity by minimizing the bolometers' exposure to radon gas during their installation in the cryostat, we perform all operations inside a dedicated cleanroom environment with a controlled radon-reduced atmosphere. In this paper, we discuss the design and performance of the CUORE Radon Abatement System and cleanroom, as well as a system to monitor the radon level in real time.Comment: 10 pages, 6 figures, 1 tabl
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