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A multi-shot target wheel assembly for high-repetition-rate, laser-driven proton acceleration

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High Power Laser Science and Engineering 2024年第2期 91-98页

作者： J.Pe?as A.Bembibre D.Cortina-Gil L.Martín A.Reija C.Ruiz M.Seimetz A.Alejo J.Benlliure instituto Galego de Física de Altas Enerxías Universidade de Santiago de Compostela Laboratorio Láser de Aceleración y Aplicaciones RIAIDT Universidade de Santiago de Compostela instituto Universitario de Física Fundamental y matemáticas y Dpto.de Didáctica de la matemática y de las Ciencias Experimentales Universidad de Salamanca instituto de Instrumentación para Imagen Molecular (I3M) CSIC-Universitat Politècnica de València

A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are introduced. The assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets,mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser irradiations. The automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target, which alongside the purpose-built design of the target wheel, enables operation at rates up to 10 Hz. Stable and continuous laser-driven proton acceleration at 10 Hz is demonstrated, with observed cut-off energy stability about 15%.

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Benchmarks for Pirá2.0,a Reading Comprehension Dataset about the Ocean,the Brazilian Coast,and Climate Change

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Data Intelligence 2024年第1期6卷 29-63页

作者： Paulo Pirozelli Marcos M.José Igor Silveira Flávio Nakasato Sarajane M.Peres Anarosa A.F.Brandão Anna H.R.Costa Fabio G.Cozman Universidade de São Paulo Ringgold Standard Institution-instituto de Estudos Avançados Av.370 São Paulo 05508-900Brazil Universidade de São Paulo Ringgold Standard Institution-instituto de matemática e Estatística Av.370 São Paulo 05508-900Brazil Universidade de São Paulo Rua Cayowaá876 apto 141SÃO PAULO 05018-001Brazil Universidade de São Paulo Ringgold Standard Institution Escola Politécnica Av.370São Paulo 05508-900Brazil.

Piráis a reading comprehension dataset focused on the ocean,the Brazilian coast,and climate change,built from a collection of scientific abstracts and reports on these *** dataset represents a versatile language resource,particularly useful for testing the ability of current machine learning models to acquire expert scientific *** its potential,a detailed set of baselines has not yet been developed for Pirá.By creating these baselines,researchers can more easily utilize Piráas a resource for testing machine learning models across a wide range of question answering *** this paper,we define six benchmarks over the Pirádataset,covering closed generative question answering,machine reading comprehension,information retrieval,open question answering,answer triggering,and multiple choice question *** part of this effort,we have also produced a curated version of the original dataset,where we fixed a number of grammar issues,repetitions,and other ***,the dataset has been extended in several new directions,so as to face the aforementioned benchmarks:translation of supporting texts from English into Portuguese,classification labels for answerability,automatic paraphrases of questions and answers,and multiple choice *** results described in this paper provide several points of reference for researchers interested in exploring the challenges provided by the Pirádataset.

关键词： Natural language processing Question answering Benchmarks Language resource DomainOriented dataset Scientific knowledge text dataset

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A Probabilistic description of the Impact of Vaccine-Induced Immunity in the Dynamics of COVID-19 Transmission

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Open Journal of Modelling and Simulation 2024年第2期12卷 59-73页

作者： Javier Blecua Juan Fernández-Recio José Manuel Gutiérrez instituto de Ciencias de la Vid y del Vino (ICVV) CSIC-Universidad de La Rioja-Gobierno de La Rioja Logro&#241o Spain departamento de matemá ticas y Computaci&#243n Universidad de La Rioja Logro&#241o Spain

The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.

关键词： COVID-19 Transmission Dynamics Probabilistic Model Bayesian Analysis Markov Chain Monte Carlo

Efficient Splitting Methods Based on Modified Potentials:Numerical Integration of Linear Parabolic Problems and Imaginary Time Propagation of the Schrodinger Equation

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Communications in Computational Physics 2023年第4期33卷 937-961页

作者： Sergio Blanes Fernando Casas Cesáreo González Mechthild Thalhammer Universitat Politècnica de València Instituto de Matemática Multidisciplinar46022 ValenciaSpain Universitat Jaume I IMAC and Departament de Matemàtiques12071 CastellónSpain Universidad de Valladolid Departamento de Matemática Aplicada47011 ValladolidSpain Leopold–Franzens–Universität Innsbruck Institut für Mathematik6020 InnsbruckAustria.

We present a new family of fourth-order splitting methods with positive coefficients especially tailored for the time integration of linear parabolic problems and,in particular,for the time dependent Schrodinger equation,both in real and imaginary *** are based on the use of a double commutator and a modified processor,and are more efficient than other widely used schemes found in the ***,for certain potentials,they achieve order *** examples in one,two and three dimensions clearly illustrate the computational advantages of the new schemes.

关键词： Schrodinger equation imaginary time propagation parabolic equations operator splitting methods modified potentials

Marriage Market with Indifferences: A Linear Programming Approach

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Journal of the Operations Research Society of China 2023年第1期11卷 219-242页

作者： Noelia Juarez Pablo A.Neme Jorge Oviedo instituto de matemática Aplicada San Luis IMASLRedNIEUniversidad Nacional de San Luis and CONICETD5700HHWSan LuisRepublica Argentina

We study stable and strongly stable matchings in the marriage market with indifference in their *** characterize the stable matchings as integer extreme points of a convex *** give an alternative proof for the integrity of the strongly stable matching ***,we compute men-optimal(women-optimal)stable and strongly stable matchings using linear *** preferences are strict,we find the men-optimal(women-optimal)stable matching.

关键词： Matching markets The marriage market with indifferences Optimal stable matchings Linear programming

Some additive results on Drazin inverse

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Applied Mathematics(A Journal of Chinese Universities) 2015年第4期30卷 479-490页

作者： LIU Xiao-ji QIN Xiao-lan Julio Benítez Faculty of Science Guangxi University for Nationalities Universidad Politécnica de Valencia Instituto de Matemática Multidisciplinar

In this paper, we investigate additive results of the Drazin inverse of elements in a ring R. Under the condition ab = ha, we show that a ＋ b is Drazin invertible if and only if aaD （a ＋ b） is Drazin invertible, where the superscript D means the Drazin inverse. Furthermore we find an expression of （a ＋ b）D. As an application we give some new representations for the Drazin inverse of a 2 × 2 block matrix.

关键词： Drazin inverse ring block matrix.

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Parameter estimation in Manneville–Pomeau processes

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Probability, Uncertainty and Quantitative Risk 2023年第2期8卷 213-234页

作者： Barbara P.Olbermann Sílvia R.C.Lopes Artur O.Lopes Faculdade de matemática-PUCRS 90650-002 Porto AlegreRSBrazil instituto de matemática e Estatística-UFRGS 91500-900 Porto AlegreRSBrazil

In this paper,we study a class of stochastic processes{X_(t)}t∈N,where X_(t)=φ■T_(s)^(t)(X_(0))is obtained from the iterations of the transformation T_(s),invariant for an ergodic probabilityμ_(s)on[0,1]and a certain constant by partial functionφ:[0,1]→*** consider here the family of transformations T_(s):[0,1]→[0,1]indexed by a parameters>0,known as the Manneville–Pomeau family of *** autocorrelation function of the resulting process decays hyperbolically(or polynomially)and we obtain efficient methods to estimate the parameter s from a finite time *** a consequence,we also estimate the rate of convergence of the autocorrelation decay of these *** compare different estimation methods based on the periodogram function,the smoothed periodogram function,the variance of the partial sum,and the wavelet *** obtain our results we analyzed the properties of the spectral density function and the associated Fourier series.

关键词： Manneville–Pomeau maps Long and not so long dependence Estimation Autocorrelation decay Spectral density function

An ETD Method for American Options under the Heston Model

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Computer Modeling in Engineering & Sciences 2020年第8期124卷 493-508页

作者： Rafael Company Vera N.Egorova Lucas Jódar Ferran Fuster Valls instituto de matemática multidisciplinar Universitat Politècnica de ValènciaValencia46022Spain depto.de matemática Aplicada y Ciencias de la Computación Universidad de CantabriaSantander39005Spain Nfoque Advisory Services Madrid28001Spain

A numerical method for American options pricing on assets under the Heston stochastic volatility model is developed.A preliminary transformation is applied to remove the mixed derivative term avoiding known numerical drawbacks and reducing computational *** boundary is treated by the penalty *** nonlinear partial differential equation is solved numerically by using the method of *** full discretization the exponential time differencing method is *** analysis establishes the stability and positivity of the proposed *** numerical convergence behaviour and effectiveness are investigated in extensive numerical experiments.

关键词： Heston model American option pricing exponential time differencing semi-discretization

Inequalities for the Extended Best Polynomial Approximation Operator in Orlicz Spaces

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Acta Mathematica Sinica,English Series 2019年第2期35卷 185-203页

作者： Sonia ACINAS Sergio FAVIER Felipe ZO departamento de matemática Facultad de Ciencias y Exactas NaturalesUniversidad Nacional de La Pampa instituto de matemática Aplicada San Luis IMASLUniversidad Nacional de San Luis and CONICET departamento de matemática Universidad Nacional de San Luis

In this paper we pursue the study of the best approximation operator extended from L~Φ to L~φ, where φ denotes the derivative of the function Φ. We get pointwise convergence for the coefficients of the extended best approximation polynomials for a wide class of function f, closely related to the Calder′on–Zygmund class t_m^p(x) which had been introduced in 1961. We also obtain weak and strong type inequalities for a maximal operator related to the extended best polynomial approximation and a norm convergence result for the coefficients is derived. In most of these results, we have to consider Matuszewska–Orlicz indices for the function φ.

关键词： Orlicz spaces extended best polynomial approximation pointwise and norm convergence weak and strong type inequalities Orlicz indices

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