803 research outputs found

    Application of Statistical Learning Control to the Design of a Fixed-Order Controller for a Flexible Beam

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    This paper shows how probabilistic methods and statistical learning theory can provide approximate solutions to “difficult” control problems. The paper also introduces bootstrap learning methods to drastically reduce the bound on the number of samples required to achieve a performance level. These results are then applied to obtain more efficient algorithms which probabilistically guarantee stability and robustness levels when designing controllers for uncertain systems. The paper includes examples of the applications of these methods

    Statistical learning control of delay systems: theory and algorithms

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    Recently, probabilistic methods and statistical learning theory have been shown to provide approximate solutions to “difficult” control problems. Unfortunately, the number of samples required in order to guarantee stringent performance levels may be prohibitively large. In this paper, using recent results by the authors, a more efficient statistical algorithm is presented. Using this algorithm we design static output controllers for a nonlinear plant with uncertain delay

    Statistical controller design for the linear benchmark problem

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    In this paper some fixed-order controllers are designed via statistical methods for the benchmark problem originally presented at the 1990 American Control Conference. Based on some recent results by the authors, it is shown that the statistical approach is a valid method to design robust controllers. Two different controllers are proposed and their performance are compared with controllers with the same structure, designed using different techniques

    Nuclear techniques and the particulate matter pollution in big harbours

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    The impact of big harbours on the air quality is an important issue both from the environmental and the economical point of view. The harbour of Genoa is the largest in Italy and one of the major ports of the Mediterranean. We have determined the fraction of Particulate Matter (PM) concentration in town due to the heavy oil combustion of the diesel engines of the vessels in the harbour. This turned out to be 12% in PM10 and 25% in PM2.5 and PM1, with about 85% of the PM from this source concentrated in particles with aerodynamic diameter, Dae < 1 ÎĽm. We could also point out a link between concentration peaks of the tracers of heavy oil combustion (V and Ni) and the ferryboats traffic. The key tool in this work was the coupling between particular sampling devices and some Ion Beam Analysis (IBA) techniques, in particular Particle Induced X-ray Emission (PIXE), which belong to the broader category of nuclear techniques in applied physics

    On Subexponentials, Synthetic Connectives, and Multi-level Delimited Control

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    International audienceWe construct a partially-ordered hierarchy of delimited control operators similar to those of the CPS hierarchy of Danvy and Filinski. However, instead of relying on nested CPS translations, these operators are directly interpreted in linear logic extended with subexponentials (i.e., multiple pairs of ! and ?). We construct an independent proof theory for a fragment of this logic based on the principle of focusing. It is then shown that the new constraints placed on the permutation of cuts correspond to multiple levels of delimited control

    Elemental characterization of PM10, PM2.5 and PM1 in the town of Genoa (Italy)

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    The particulate matter (PM) concentration and composition, the PM10, PM2.5, PM1 fractions, were studied in the urban area of Genoa, a coastal town in the northwest of Italy. Two instruments, the continuous monitor TEOM and the sequential sampler PARTISOL, were operated almost continuously on the same site from July 2001 to September 2004. Samples collected by PARTISOL were weighted to obtain PM concentration and then analysed by PIXE (particle induced X-ray emission) and by ED-XRF (energy dispersion X-ray fluorescence), obtaining concentrations for elements from Na to Pb. Some of the filters used in the TEOM microbalance were analysed by ED-XRF to calculate Pb concentration values averaged over 7\u201330 d periods

    JARDINES DEL HOTEL TAORO [Material gráfico]

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    * POSITIVO DE PLACA ORIGINAL. ADQUIRIDA POR EL COLECCIONISTA EN TENERIFE.FOTO VDE VISTA GENERAL DE LOS JARDINES DEL HOTEL TAOROCopia digital. Madrid : Ministerio de EducaciĂłn, Cultura y Deporte. SubdirecciĂłn General de CoordinaciĂłn Bibliotecaria, 201

    Therapeutic immunization with HIV-1 Tat reduces immune activation and loss of regulatory T-cells and improves immune function in subjects on HAART.

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    Although HAART suppresses HIV replication, it is often unable to restore immune homeostasis. Consequently, non-AIDS-defining diseases are increasingly seen in treated individuals. This is attributed to persistent virus expression in reservoirs and to cell activation. Of note, in CD4(+) T cells and monocyte-macrophages of virologically-suppressed individuals, there is continued expression of multi-spliced transcripts encoding HIV regulatory proteins. Among them, Tat is essential for virus gene expression and replication, either in primary infection or for virus reactivation during HAART, when Tat is expressed, released extracellularly and exerts, on both the virus and the immune system, effects that contribute to disease maintenance. Here we report results of an ad hoc exploratory interim analysis (up to 48 weeks) on 87 virologically-suppressed HAART-treated individuals enrolled in a phase II randomized open-label multicentric clinical trial of therapeutic immunization with Tat (ISS T-002). Eighty-eight virologically-suppressed HAART-treated individuals, enrolled in a parallel prospective observational study at the same sites (ISS OBS T-002), served for intergroup comparison. Immunization with Tat was safe, induced durable immune responses, and modified the pattern of CD4(+) and CD8(+) cellular activation (CD38 and HLA-DR) together with reduction of biochemical activation markers and persistent increases of regulatory T cells. This was accompanied by a progressive increment of CD4(+) T cells and B cells with reduction of CD8(+) T cells and NK cells, which were independent from the type of antiretroviral regimen. Increase in central and effector memory and reduction in terminally-differentiated effector memory CD4(+) and CD8(+) T cells were accompanied by increases of CD4(+) and CD8(+) T cell responses against Env and recall antigens. Of note, more immune-compromised individuals experienced greater therapeutic effects. In contrast, these changes were opposite, absent or partial in the OBS population. These findings support the use of Tat immunization to intensify HAART efficacy and to restore immune homeostasis. TRIAL REGISTRATION: ClinicalTrials.gov NCT00751595

    Models of a Non-Associative Composition

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    International audienceWe characterise the polarised evaluation order through a categorical structure where the hypothesis that composition is associative is relaxed. Duploid is the name of the structure, as a reference to Jean-Louis Loday's duplicial algebras. The main result is a reflection Adj→Dupl where Dupl is a category of duploids and duploid functors, and Adj is the category of adjunctions and pseudo maps of adjunctions. The result suggests that the various biases in denotational semantics: indirect, call-by-value, call-by-name... are a way of hiding the fact that composition is not always associative.Nous caractérisons l'ordre d'évaluation polarisé à travers une structure catégorielle dont l'hypothèse que la composition est associative est relâchée. Duploïde est le nom de la structure, par référence aux algèbres dupliciales de Loday. Le résultat principal est une réflection Adj→Dupl où Dupl est une catégorie des duploïdes et des foncteurs de duploïdes, et Adj est la catégorie des adjonctions et des pseudo-morphismes d'adjonctions. Le résultat suggère que les biais des sémantiques dénotationnelles: indirectes, en appel par valeur, en appel par nom... sont des façons de cacher le fait que la composition n'est pas toujours associative
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