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Performance Improvement of Discrete-time linear Control Systems Subject to Varying Sampling Rates Using the Tikhonov Regularization Method

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International Journal of Automation and computing 2020年第3期17卷 453-463页

作者： Fernando Agustin Pazos anibal Zanini Amit Bhaya Department of Electronics and Telecommunication Engineering State University of Rio de JaneiroRua São Fransciso Xavier 524Rio de Janeiro 20550-900Brazil Universidad de Buenos Aires-ITHES-UBA-CONICET Departamento de Ingenieria QuimicaPabellón de IndustriasCiudad UniversitariaBuenos Aires C1428EGAArgentina Department of Electrical Engineering Federal University of Rio de JaneiroPEE/COPPE/UFRJRio de Janeiro 21945-970Brazil

Methods to stabilize discrete-time linear control systems subject to variable sampling rates,i.e.,using state feedback controllers,are well known in the *** recent works address the use of the Tikhonov regularization method,originally designed to attenuate the noise effects on ill-posed problems,with the aim of improving performance and stabilizing approximately controllable dynamical *** by these works,we propose the use of a feedback controller designed using the Tikhonov method to regularize discrete-time linear systems subject to varying sampling *** goal is to minimize an error function,thus improving the performance of the closed loop system and reducing the possibility of *** examples show the effectiveness of the proposed method.

关键词： Discrete-time switched systems Tikhonov regularization varying sampling rates discrete-time control systems networked control systems

A PD-Type State-Dependent Riccati Equation With Iterative learning Augmentation for Mechanical Systems

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IEEE/CAA Journal of Automatica Sinica 2022年第8期9卷 1499-1511页

作者： Saeed Rafee Nekoo JoséÁngel Acosta Guillermo Heredia anibal Ollero GRVC Robotics lab. Depto de Ingeniería de Sistemas y AutomáticaEscuela Técnica Superior de IngenieríaUniversidad de SevillaSeville 41092Spain

This work proposes a novel proportional-derivative(PD)-type state-dependent Riccati equation(SDRE)approach with iterative learning control(IlC)*** the one hand,the PD-type control gains could adopt many useful available criteria and tools of conventional PD *** the other hand,the SDRE adds nonlinear and optimality characteristics to the controller,i.e.,increasing the stability *** advantages with the IlC correction part deliver a precise control law with the capability of error reduction by *** SDRE provides a symmetric-positive-definite distributed nonlinear suboptimal gain K(x)for the control input law u=–R–1(x)BT(x)K(x)*** sub-blocks of the overall gain R–1(x)BT(x)K(x),are not necessarily symmetric positive definite.A new design is proposed to transform the optimal gain into two symmetric-positive-definite gains like PD-type controllers as u=–KSP(x)e–KSD(x)?.The new form allows us to analytically prove the stability of the proposed learning-based controller for mechanical systems;and presents guaranteed uniform boundedness in finite-time between learning *** symmetric PD-type controller is also developed for the state-dependent differential Riccati equation(SDDRE)to manipulate the final *** SDDRE expresses a differential equation with a final boundary condition,which imposes a constraint on time that could be used for finitetime ***,the availability of PD-type finite-time control is an asset for enhancing the conventional classical linear controllers with this *** learning rules benefit from the gradient descent method for both regulation and tracking *** of the advantages of this approach is a guaranteed-stability even from the first loop of learning.A mechanical manipulator,as an illustrative example,was simulated for both regulation and tracking *** experimental validation was done to show the capability of the system in practice by the implementation of the proposed metho

关键词： Closed-loop iterative learning control(IlC) PD-type SDRE SDDRE symmetric

ANonmonotone Projected Gradient Method for Multiobjective Problems on Convex Sets

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Journal of the Operations Research Society of China 2024年第2期12卷 410-427页

作者： Gabrie anibal Carrizo Nadia Soledad Fazzio Maria laura Schuverdt Department of Mathematics National University of the SouthBahia BlancaArgentina Department of Mathematics University of La PlataLa PlataArgentina

In this work we consider an extension of the classical scalar-valued projected gradient method for multiobjective problems on convex *** in Fazzio et al.(Optim lett 13:1365-1379,2019)a parameter which controls the step length is considered and an updating rule based on the spectral gradient method from the scalar case is *** the present paper,we consider an extension of the traditional nonmonotone approach of Grippo et al.(SIAM J Numer Anal 23:707-716,1986)based on the maximum of some previous function values as suggested in Mita et al.(J Glob Optim 75:539-559,2019)for unconstrained multiobjective optimization *** prove the accumulation points of sequences generated by the proposed algorithm,if they exist,are stationary points of the original *** experiments are reported.

关键词： Multiobjective optimization Projected gradient methods Nonmonotone line search Global convergence

Impact of Adrenaline or Cortisol Injection on Meat Quality Development of Merino Hoggets

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Journal of Integrative Agriculture 2013年第11期12卷 1931-1936页

作者： Dario G Pighin Sebastian A Cunzolo Maria Zimerman Adriana A Pazos Ernesto Domingo anibal J Pordomingo Gabriela Grigioni Institute of Food Technology National Institute of Agricultural Technology(INTA)De Los Reseros y Las CabaasMorón 1708Argentina National Council of Scientific and Technological Research-CONICET Av.Rivadavia 1917Buenos Aires 1033Argentina Faculty of Agricultural and Food Sciences University of Moron Experimental Station-INTA Bariloche Modesta Victoria 4450San Carlos de Bariloche Río Negro 8400Argentina Institute of Food Technology National Institute of Agricultural Technology(INTA)De Los Reseros y Las Caba asMorón 1708Argentina Experimental Station-INTA Anguil Ruta Nacional No 5 Km.580(6326)La Pampa 6326Argentina

Increased levels of stress hormones in the muscle could lead to post mortem metabolic/structural modiifcations that could be relfected on meat quality. The present study investigated the metabolic effect of either adrenaline or cortisol injected into lambs in order to obtain an animal model of acute stress. Results showed that adrenaline or cortisol injection lead to glucose metabolism and muscle temperature increase. Muscle pH immediately post mortem was affected by adrenaline treatment. Water holding capacity （WHC） of fresh muscle, ifnal muscle pH and temperature registered at 24 h post mortem were not affected by injected hormones. Hardness and adhesiveness of lD muscle evaluated 3 d post mortem tended to increase as a result of adrenaline or cortisol injection. Results demonstrated that injected hormones were able to affect the post mortem muscle biochemistry and the pH/T curve independently of ifnal muscle pH.

关键词： stress hormones muscle metabolism meat quality

Monitoring Heat Waves and Their Impacts on Summer Crop Development in Southern Brazil

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Agricultural Sciences 2014年第4期5卷 353-364页

作者： anibal Gusso Jorge Ricardo Ducati Mauricio Roberto Veronez Victor Sommer luiz Gonzaga da Silveira Junior Environmental Engineering Vale do Rio dos Sinos University(UNISINOS)Sao LeopoldoBrazil Center for Remote Sensing and Meteorological Research Federal University of Rio Grande do Sul(UFRGS)Porto AlegreBrazil Vizlab-Advanced Visualization laboratory Vale do Rio dos Sinos University(UNISINOS)Sao LeopoldoBrazil Astronomy Department Federal University of Rio Grande do Sul(UFRGS)Porto AlegreBrazil Graduate Program in Geology Vale do Rio dos Sinos University(UNISINOS)Sao LeopoldoBrazil Crop Breeding Foundation(Fundacao Pró-Sementes) Passo FundoBrazil Graduate Program in Applied Computing Vale do Rio dos Sinos University(UNISINOS)São LeopoldoBrazil

Periods in the soybean summer cycle that are sensitive to the occurrence of high temperatures were studied. An analysis was performed on the variability of soybean yields associated with crop canopy temperatures during key development periods. A land surface temperature (lST) data series from MODIS (Moderate Resolution Imaging Spectroradiometer) on the Aqua satellite was processed between 2003 and 2012 that covered the entire state of Rio Grande do Sul, in Brazil. Enhanced vegetation index (EVI) data from MODIS on the Terra satellite were used to monitor the lST during different phenological stages. Spatially interpolated maps of soybean yield distributions were generated using data obtained from Instituto Brasileiro de Geografia e Estatística (IBGE) at state and municipality levels. The results indicate that canopy-lST occurrence in mid-February, during the grain filling, is most correlated to yield reduction (R2 = 0.82 and RMSD = 14.4%). At the state level, the average yield is 2003 kg·ha-1 with a standard deviation of 308 kg·ha-1. The overall average of the canopy-lST is 305.0 K (31.8°C) with a standard deviation of 1.9 K. The slope of the downward linear relationship between canopy-lST and yield was -28.7%. These results indicate that monitoring heat wave events can provide important information for characterising agriculture vulnerability.

关键词： land Surface Temperature Soybean Remote Sensing Canopy Vegetation Index MODIS Data

Scale dependency of liolaemus lizards＇ home range in response to different environmental variables

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Current Zoology 2016年第6期62卷 521-530页

作者： Oscar anibal STEllATEllI Carolina BlOCK Debora lina MORENO-AZOCAR laura Estela VEGA Juan Pablo ISACCH Felix Benjamin CRUZ laboratorio de Vertebrados Departamento de Biologia Instituto de Investigaciones Marinas y Costeras (IIMyC) CONICET-Facultad de Ciencias Exactas y Naturales Universidad Nacional de Mar del Plata. Defin Funes 3250 (B7602AYJ) Mar del Plata Buenos Aires Argentina Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) CONICET-Universidad Nacional del Comahue. Quintral 1250 (8400) San Carlos de Bariloche Rio Negro Argentina.

Animal habitat-use patterns cannot be isolated from scale issues. Consequently, multi-scale studies provide a complete characterization of ecological patterns that can further explain the observed variation. liolaemus constitutes the world＇s second most speciose lizard genus. In this study, we assessed the relationships between home range size and environmental variables at 3 different spatial scales. The study at a local and regional scale was focused on the habitat specialist liolaemus multimaculatus. The lizard＇s home range was calculated using the minimum convex polygon method in populations from grassland sites of the coastal sand dunes of the Argentinean Pampas under 2 different conditions, with or without forestations of Acacia Iongifolia. On the other hand, at a geographical scale we considered the evolutionary implications of 20 species of liolaemus. Home range size, phylogeny, ecological, environmental, and climatic data were ob- tained from the literature and remote sensing. l. multimaculatus home range varied from 12.66 to 570.00 m. Regionally, this species had smaller home ranges in forested habitats （X： 94.02 m2） com- pared with the non-forested sites （X： 219.78m2）. Habitat structure, vegetation types, and food availability would explain the space use at finer scales. When the 20 species of liolaernus were considered, high mean air temperature and broad thermal amplitudes showed an inverse relationship with home range size. Neither net primary productivity nor phylogeny was good predictors for home range variation at geographical scale. This study highlights the scale dependence of the explicative capability of a set of environmental and intrinsic variables on home range patterns.

关键词： environmental factors home range liolaemus lizard scales

South Atlantic Anomaly Variations during Seasons

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Natural Science 2023年第7期15卷 207-221页

作者： Marilia Hagen anibal Azevedo Instituto de Física Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Faculdade de Ciencias Aplicadas da Unicamp Limeira Brazil

This investigation searches the possible connections between deep and ultra-deep earthquakes in a subduction zone with unique characteristics known as Nazca-South America subduction. The earthquake events occurred in an area under the South Atlantic Magnetic Anomaly. The results pointed out that the cyclicity of earthquakes is independent of external factors and linked to internal unknown changes traced or associated with the lithosphere and upper mantle. The malleable minerals or unbreakable material could be due to a bulge of water between the two Nazca slabs sinking. The periodicity noticed from some events is opposite to the Solar Cycles, which means they enhance during the minima of cycles. Therefore, we concluded that these variations might be linked to internal causes below the crust into the lithosphere.

关键词： Nazca-South America Subduction Seasonality Deep-Depth Earthquakes

Influence of Volcanic Activity on Weather and Climate Changes

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Atmospheric and Climate Sciences 2023年第2期13卷 138-158页

作者： Marilia Hagen anibal Azevedo Instituto de Física Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil Faculdade de Ciências Aplicadas da Unicamp Limeira Brazil

This paper examines possible connections between volcanic eruptions and their consequences on the weather. Gas emissions, such as CO2 and SO2, are vital in the troposphere and change temperatures on Earth’s surface. The water vapor discharges can be moved for three atmospheric layers creating extra atmospheric rivers and disrupting the Polar vortex. All those deviations will bring consequences to the weather. It depends on the intensity, the emission type, the kind of volcano, and the location. Then, eruptions can change the atmospheric layers with sudden fluctuations unexpected for the season.

关键词： Volcanoes Tonga Manua loa Kilauea Climate Changes

Sun Disturbances on Earth’s Volcanism

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Natural Science 2023年第1期15卷 1-10页

作者： Marilia Hagen anibal Azevedo Instituto de Física Universidade do Estado do Rio de Janeiro RJ Brasil Faculdade de Ciências Aplicadas da Unicamp Limeira Brasil

This paper searches for a connection between volcanoes and solar variability. Solar events have been investigated as possible interference with hazardous natural events on Earth. The first results pointed out that during the solar minimum, the frequency and strength of volcanoes increased. However, solar variability is not the only factor disturbing volcanic eruptions;there is also seasonality. There is a double interference from the Sun on the volcanoes, one from the solar cycles, and the second is the seasons.

关键词： Volcanoes Earthquakes Solar Variability Seasons