H? robust memory controllers for networked control systems: uncertain sampling rates and time delays in polytopic domains

In this paper, the problem of controller design for networked control systems with time-varying sampling rates and time delays is investigated. By using a memory at the feedback loop, a digital robust controller that minimizes an upper bound to the Hinfin performance of the closed loop system is determined. The design conditions are obtained from the Finsler\u27s Lemma combined with the Lyapunov theory and expressed in terms of bilinear matrix inequalities. Extra variables introduced by the Finsler\u27s Lemma are explored in order to provide a better system behavior. The time-varying uncertainties are modelled using polytopic domains. The controller is obtained by the solution of an optimization problem formulated only in terms of the vertices of the polytope, avoiding grids in the parametric space. Numerical examples illustrate the efficiency of the proposed approach

H? filtering of time-varying systems with bounded rates of variation

In this paper, the problem of robust filter design for time-varying discrete-time polytopic systems with bounded rates of variation is investigated. The design conditions are obtained by using a parameter-dependent Lyapunov function and the Finsler\u27s Lemma. A robust filter, that minimizes an upper bound to the H? performance of the estimation error, is obtained as the solution of an optimization problem. A more precise geometric representation of the parameter time variation was used in order to obtain less conservative design conditions. Robust filters for time-invariant, as well as arbitrarily time-varying, polytopic systems can be obtained as a particular case of the proposed method. Numerical examples illustrate the results

H? Gain Scheduling for Discrete-Time Systems with Control Delays and Time-Varying Parameters: a BMI Approach

In this paper, the problem of gain scheduling for time-varying systems with time delays is investigated. By using a memory at the feedback loop, a discrete gain scheduled controller which minimizes an upper bound to the ,Hscrinfin performance of the closed loop system is determined. The design conditions, expressed in terms of bilinear matrix inequalities, are obtained from the Finsler\u27s Lemma combined with the Lyapunov theory. The extra variables introduced by the Finsler\u27s Lemma represent an alternative way in the search of better system behavior. The time-varying uncertainties are modeled using polytopic domains. The controller is obtained by the solution of an optimization problem formulated only in terms of the vertices of the polytope. No grids in the parametric space are used. Numerical examples illustrate the efficiency of the proposed approach

Deep learning for the classification of quenched jets

An important aspect of the study of Quark-Gluon Plasma (QGP) in ultra-relativistic collisions of heavy ions is the ability to identify, in experimental data, a subset of the jets that were strongly modified by the interaction with the QGP. In this work, we propose studying deep learning techniques for this purpose. Samples of $Z+$jet events were simulated in vacuum and medium and used to train deep neural networks with the objective of discriminating between medium- and vacuum-like jets. Dedicated Convolutional Neural Networks, Dense Neural Networks and Recurrent Neural Networks were developed and trained, and their performance was studied. Our results show the potential of these techniques for the identification of jet quenching effects induced by the presence of the QGP.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Alleviating the present tension between T2K and NOν\nuA with neutrino New Physics at source

Since neutrino oscillation was observed, several experiments have been built to measure its parameters. NO$\nu$A and T2K are two long-baseline experiments dedicated to measuring mainly the mixing angle $\theta_{23}$, the charge-parity conjugation phase $\delta_{\rm CP}$, and the mass ordering. However, there is a tension in current data. The T2K allowed region is almost excluded by the NO$\nu$A result at the $90\%$ confidence level. We propose a non-standard interaction (NSI) in neutrino production to relieve this tension. The NSI is computed through quantum field theory (QFT) formalism, where we derive perturbative analytical formulae considering NSI in the pion decay. Within this new approach, we can alleviate NO$\nu$A and T2K tension for a NSI complex parameters of order $10^{-3}$. We show the new phase has a degeneracy to the Dirac CP phase of the form $\delta_{\rm CP} \pm \phi= 1.5\pi$ being a possible source of violation of charge-parity symmetry

The linear interpolation method: a sampling theorem approach

A lecture note introducing the sampling theorem as an interpolation method is presented. The relationship between piecewise linear approximation and the sampling theorem is highlighted by the use of triangular pulses instead of sampling functions. Furthermore, a comparison of the linear interpolation with a series on a nonorthogonal basis composed of equally spaced triangular pulses is provided. The interpolation uses the sample values of the function whereas the series coefficients are obtained by minimizing the quadratic error between the original function and the series.Uma aula sobre o teorema da amostragem como um método de interpolação é apresentada neste trabalho. A relação entre a interpolação linear e o teorema da amostragem é realçada pelo uso de pulsos triangulares aproximando funções sampling. Além disso, é feita uma comparação entre a interpolação linear e a série em uma base não ortogonal composta de pulsos triangulares igualmente espaçados. A interpolação usa os valores das amostras da função e os coeficientes da série são obtidos minimizando o erro quadrático entre a função original e a série.439444Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Convex relaxations with guaranteed convergence for control design of takagi-sugeno fuzzy systems

This paper provides convex conditions with certificates of convergence for the design of state feedback controllers that quadratically stabilize and also ensure optimal H2 and H∞ performances under quadratic stability for Takagi-Sugeno continuous-time fuzzy systems. The proposed conditions are formulated as parameter-dependent linear matrix inequalities (LMIs) that have extra variables from Finsler's lemma and parameters belonging to the unit simplex. The fuzzy control law is written as a state feedback gain that is a homogeneous polynomial of degree g, encompassing the parallel distributed compensator as a special case when g = 1. Algebraic properties of the system parameters and recent results of positive polynomials are used to construct LMI relaxations which, differently from most relaxations in the literature, asymptotically converge to a solution whenever such solution exists. Due to the degree of freedom obtained with the extra variables, the conditions presented in the paper are an improvement over earlier results based on Pólya's theorem and can be viewed as an alternative to the use of techniques based on the relaxation of quadratic forms. The numerical efficiency in terms of precision and computational effort is demonstrated by means of comparisons with other methods from the literature.Este artigo fornece condições convexas com convergência garantida para o projeto de controladores por realimentação de estados que estabilizam quadraticamente e também asseguram desempenhos ótimos H2 e H∞ sob estabilidade quadrática para sistemas nebulosos de Takagi-Sugeno contínuos no tempo. As condições propostas são formuladas como desigualdades matriciais lineares (LMIs) dependentes de parâmetros com variáveis de folga provenientes do Lema de Finsler e com parâmetros pertencentes ao simplex unitário. A lei de controle nebulosa é dada por um ganho de realimentação de estados que é um polinômio homogêneo de grau g, que tem como caso particular o compensador paralelo distribuído quando g = 1. Propriedades algébricas dos parâmetros do sistema e resultados recentes sobre positividade de polinômios são usados para construir relaxações LMIs que, diferentemente da maioria das relaxações da literatura, convergem assintoticamente para a solução sempre que esta existir. Graças ao grau de liberdade obtido pelo uso de variáveis de folga, as condições apresentadas no artigo representam avanços em relação a condições recentemente publicadas baseadas no Teorema de Pólya, e podem ser vistas como uma alternativa a técnicas baseadas na relaxação de formas quadráticas. A eficiência numérica em termos de precisão e esforço computacional é demonstrada por meio de comparações com outros métodos da literatura.8295Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Acute Strenuous Exercise Induces an Imbalance on Histone H4 Acetylation/Histone Deacetylase 2 and Increases the Proinflammatory Profile of PBMC of Obese Individuals

This study evaluated the response of global histone H4 acetylation (H4ac), histone deacetylase 2 (HDAC2) activity, as well as the production of proinflammatory cytokines and monocyte phenotypes of lean and obese males after exercise. Ten lean and ten obese sedentary men were submitted to one session of strenuous exercise, and peripheral blood mononuclear cells (PBMC) were stimulated in vitro with lipopolysaccharide (LPS). Global H4ac levels, HDAC2 activity in PBMC, and IL-6, IL-8, and TNF-α production were analyzed. Monocyte phenotype was determined in accordance with the expression of CD14 and CD16. At rest, obese individuals presented higher frequency of proinflammatory CD14+CD16+ monocytes. LPS induced a significant augment in global H4ac and in the production of IL-6, IL-8, and TNF-α mainly in obese individuals. After exercise, the increased production of IL-8 and TNF-α and peripheral frequency of CD14+CD16+ were observed in both groups. In addition, exercise also induced a significant hyperacetylation of histone H4 and decreased HDAC2 activity in both nonstimulated and LPS-stimulated PBMC of obese individuals. Our data indicate that the obesity impacts on H4ac levels and that strenuous exercise leads to an enhanced chronic low-grade inflammation profile in obesity via an imbalance on H4ac/HDAC2

Enose lab made with vacuum sampling: quantitative applications

A lab-made electronic nose (Enose) with vacuum sampling and a sensor array, comprising nine metal oxide semiconductor Figaro gas sensors, was tested for the quantitative analysis of vapor–liquid equilibrium, described by Henry’s law, of aqueous solutions of organic compounds: three alcohols (i.e., methanol, ethanol, and propanol) or three chemical compounds with different functional groups (i.e., acetaldehyde, ethanol, and ethyl acetate). These solutions followed a fractional factorial design to guarantee orthogonal concentrations. Acceptable predictive ridge regression models were obtained for training, with RSEs lower than 7.9, R2 values greater than 0.95, slopes varying between 0.84 and 1.00, and intercept values close to the theoretical value of zero. Similar results were obtained for the test data set: RSEs lower than 8.0, R2 values greater than 0.96, slopes varying between 0.72 and 1.10, and some intercepts equal to the theoretical value of zero. In addition, the total mass of the organic compounds of each aqueous solution could be predicted, pointing out that the sensors measured mainly the global contents of the vapor phases. The satisfactory quantitative results allowed to conclude that the Enose could be a useful tool for the analysis of volatiles from aqueous solutions containing organic compounds for which Henry’s law is applicable.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FED-ER under Programme PT2020 for financial support by national funds FCT/MCTES to CIMO (UID/AGR/00690/2019) and SusTEC (LA/P/0007/2020)info:eu-repo/semantics/publishedVersio

Condições LMI para estabilidade robusta de politopos de matrizes polinomiais

Sufficient conditions for checking the robust stability of a polytope of polynomial matrices are proposed in this paper. Simple feasibility tests performed in a convex set of linear matrix inequalities defined at the vertices of the polytope yield sufficient conditions for the robust stability of the entire domain. Both continuous-time (left half-plane) and discrete-time stability (unit disk) are investigated. Improved sufficient conditions are also presented, containing the previous ones as special cases, providing an efficient numerical method for the robust stability analysis of polytopes of polynomial matrices. Numerical comparisons with quadratic stability and with results obtained from other recent methods in the literature show that the proposed conditions provide less conservative evaluations.Condições suficientes para a estabilidade robusta de um politopo de matrizes polinomiais são propostas neste artigo. Os testes de estabilidade são baseados em desigualdades matriciais lineares formuladas nos vértices do politopo de incertezas que, se factíveis, fornecem uma função de Lyapunov dependente de parâmetros que garante a estabilidade de qualquer polinômio matricial no domínio de incerteza. São analisados os casos de estabilidade a tempo contínuo (semi-plano esquerdo) e a tempo discreto (círculo unitário). Condições ainda mais abrangentes são também apresentadas, contendo as anteriores como casos particulares, proporcionando um método numérico eficaz para a análise da estabilidade robusta de polinômios matriciais. Experimentos numéricos mostram que as condições propostas produzem resultados menos conservadores quando comparados aos obtidos com a estabilidade quadrática e aos obtidos através de métodos recentes da literatura.388400Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES