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arXiv 2022年

作者： Cameron, Peter J. Fernandes, Maria Elisa Leemans, Dimitri School of Mathematics and Statistics University of St Andrews North Haugh Fife St AndrewsKY16 9SS United Kingdom Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Portugal Université Libre de Bruxelles Département de Mathématique C.P.216 - Algèbre et Combinatoire Boulevard du Triomphe Brussels1050 Belgium

If G is a transitive group of degree n having a string C-group of rank r ≥ (n + 3)/2, then G is necessarily the symmetric group Sn. We prove that if n is large enough, up to isomorphism and duality, the number of string C-groups of rank r for Sn (with r ≥ (n + 3)/2) is the same as the number of string C-groups of rank r + 1 for Sn+1. This result and the tools used in its proof, in particular the rank and degree extension, imply that if one knows the string C-groups of rank (n + 3)/2 for Sn with n odd, one can construct from them all string C-groups of rank (n+3)/2+k for Sn+k for any positive integer k. The classification of the string C-groups of rank r ≥ (n+3)/2 for Sn is thus reduced to classifying string C-groups of rank r for S2r−3. A consequence of this result is the complete classification of all string C-groups of Sn with rank n − κ for κ ∈ {1, . . ., 6}, when n ≥ 2κ + 3, which extends previously known results. The number of string C-groups of rank n − κ, with n ≥ 2κ + 3, of this classification gives the following sequence of integers indexed by κ and starting at κ = 1: (1, 1, 7, 9, 35, 48) This sequence of integers is new according to the On-Line Encyclopedia of Integer Sequences. It will be available as sequence number *** Codes 20B30, 52B11 © 2022, CC BY.

关键词： Classification (of information)

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development of quality dashboards: A case study of an electronic product 4

Development of quality dashboards: A case study of an electr...

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4th International Conference on Quality Engineering and Management, ICQEM 2020

作者： Mendes, A.R. Xambre, A.R. Alvelos, H. Department of Economics Management Industrial Engineering and Tourism University of Aveiro Aveiro3810-193 Portugal Department of Economics Management Industrial Engineering and Tourism Center for Research and Development in Mathematics and Applications University of Aveiro Aveiro3810-193 Portugal

ISBN: (纸本)9789895491100

Purpose - This work aims to study the management of products' and process' characteristics to ensure the products' quality, by leveraging the use of dashboards, that collect, analyse and display information about the quality of the production in near-real-time. Methodology - The methodology used was based on the CRISP-DM reference model that comprises six stages: Business Understanding, Data Understanding, Data Preparation, Modelling, Evaluation and Deployment. The last two stages were not implemented. Findings - The main findings of this work focus on the use of recent IT developments to build systems that assist the work of the quality team, with the implementation of a quality dashboard. It was also important to note that the use of dashboards with near-real-time data helps the decision making process of the stakeholders. Practical implications - The resulting dashboards were considered very useful by the company, and the work developed served as pilot project on the creation of quality dashboards. Originality - This work combines the fields of data analysis, quality and process monitorization techniques. It addresses the need to use data in a meaningful, easy and fast manner, as a way to provide stakeholders with the necessary insights about the quality of the production. © 2020 Universidade do Minho. All rights reserved.

关键词： CRISP-DM Critical to Quality Characteristics Dashboards Quality Control

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Preface of the "6th Symposium on Modelling and Simulation in Computer Sciences and Engineering"

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AIP Conference Proceedings 2022年第1期2425卷

作者： Miranda, Daniel Miranda, Francisco Abreu, Carlos 2Ai - School of Technology IPCA Barcelos Portugal Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun'Álvares Viana do Castelo 4900-347 Portugal Center for Research and Development in Mathematics and Applications (CIDMA) Department of Mathematics University of Aveiro Aveiro 3810-193 Portugal PROMETHEUS Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun'Álvares Viana do Castelo 4900-347 Portugal

Daniel Miranda, Francisco Miranda, Carlos Abreu; Preface of the “6th Symposium on Modelling and Simulation in Computer Sciences and Engineering”, AIP Conference

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Coupled scalar-Proca soliton stars

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Physical Review D 2023年第4期108卷 044044-044044页

作者： Alexandre M. Pombo João M. S. Oliveira Nuno M. Santos CEICO Institute of Physics of the Czech Academy of Sciences Na Slovance 2 182 21 Praha 8 Czechia Centro de Matemática Universidade do Minho 4710-057 Braga Portugal Departamento de Física Instituto Superior Técnico—IST Universidade de Lisboa—UL Avenida Rovisco Pais 1 1049-001 Lisboa Portugal Departamento de Matemática da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal

We construct and explore the physical properties of scalaroca stars: spherically symmetric solitonic solutions made of a complex scalar field Φ and a complex Proca field Aμ. We restrict our attention to configurations in which both fields are in the fundamental state and possess an equal mass, focusing on the cases when (i) the scalar and Proca fields are (nonlinearly) superimposed and do not interact with each other; and (ii) the scalar and Proca fields interact through the term α|Φ|2AμAμ. The solutions are found numerically for the noninteracting case (α=0) as well as for both signs of the interaction coupling constant α. While pure (i.e., single–field) Proca/scalar boson stars are the most/least massive for weakly interacting fields, one can obtain more massive solutions for a sufficiently strong interaction. Besides, in the latter case, solutions can be either in a synchronized state—in which both fields have the same frequency—or in a nonsynchronized state. In addition, we observe that the coupling between the two fields allows solitonic solutions with a real scalar field. We further comment on the possibility of spontaneous scalarization and vectorization of the interacting solitonic solution.

关键词： Fluids & classical fields in curved spacetime General relativity General relativity equations & solutions Gravitation Stars

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Towards a Geometric Theory for nD Behaviors:Conditioned Invariance and Detectability Subspaces ⁎

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IFAC-PapersOnLine 2019年第17期52卷 77-81页

作者： Ricardo Pereira Paula Rocha CIDMA - Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Aveiro Portugal SYSTEC Faculty of Engineering University of Porto Portugal

We introduce the definitions of observer, conditioned invariance and detectability subspaces for discrete multidimensional behavioral systems, based on our previous work for the continuous 1D case, as a step forward i... 详细信息

关键词： Multidimensional behavioral systems invariance observer conditioned-invariance detectability

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Asymmetric wormholes in Palatini f(R) gravity: Energy conditions, absorption, and quasibound states

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Physical Review D 2023年第2期108卷 024063-024063页

作者： Renan B. Magalhães Andreu Masó-Ferrando Gonzalo J. Olmo Luís C. B. Crispino Programa de Pós-Graduação em Física Universidade Federal do Pará 66075-110 Belém Pará Brazil Departamento de Física Teórica and IFIC Centro Mixto Universitat de València—CSIC Universitat de València Burjassot-46100 València Spain Universidade Federal do Ceará (UFC) Departamento de Física Campus do Pici Fortaleza—Ceará C.P. 6030 60455-760—Brazil Departamento de Matemática da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal

We investigate the scalar absorption spectrum of wormhole solutions constructed via the recently developed thin-shell formalism for Palatini f(R) gravity. Such wormholes come from the matching of two Reissner-Nordström spacetimes at a timelike hypersurface (shell), which, according to the junction conditions in Palatini f(R), can be stable and have either positive or negative energy density. In particular, we identified a new physically interesting configuration made out of two overcharged Reissner-Nordström spacetimes, whose absorption profile departs from that of black holes and other previously considered wormholes in the whole range of frequencies. Unlike in symmetric wormhole solutions, the asymmetry of the effective potential causes the dilution of the resonances associated to the quasibound states for the high-frequency regime. Therefore, slight asymmetries in wormhole space-times could have a dramatic impact on the observable features associated to resonant states.

关键词： Alternative gravity theories Gravitation

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Numerical evolutions of boson stars in Palatini f(R) gravity

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Physical Review D 2024年第4期109卷 044042-044042页

作者： Andreu Masó-Ferrando Nicolas Sanchis-Gual José A. Font Gonzalo J. Olmo Departamento de Física Teórica and IFIC Centro Mixto Universidad de Valencia-CSIC. Universidad de Valencia Burjassot-46100 Valencia Spain Departamento de Astronomía y Astrofísica Universitat de València Dr. Moliner 50 46100 Burjassot (València) Spain Departamento de Matemática da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal Observatori Astronòmic Universitat de València Catedrático José Beltrán 2 46980 Paterna (València) Spain Universidade Federal do Ceará (UFC) Departamento de Física Campus do Pici Fortaleza-CE C.P. 6030 60455-760 Brazil

We investigate the time evolution of spherically symmetric boson stars in Palatini f(R) gravity through numerical relativity computations. Employing a novel approach that establishes a correspondence between modified gravity with scalar matter and general relativity with modified scalar matter, we are able to use the techniques of numerical relativity to simulate these systems. Specifically, we focus on the quadratic theory f(R)=R+ξR2 and compare the obtained solutions with those in general relativity, exploring both positive and negative values of the coupling parameter ξ. Our findings reveal that boson stars in Palatini f(R) gravity exhibit both stable and unstable evolutions. The latter give rise to three distinct scenarios: migration toward a stable configuration, complete dispersion, and gravitational collapse leading to the formation of a baby universe structure.

关键词： Alternative gravity theories Experimental studies of gravity Gravitation Quantum aspects of black holes Composition of astronomical objects Numerical relativity Numerical simulations in gravitation & astrophysics

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Duality theory for enriched Priestley spaces

arXiv

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arXiv 2020年

作者： Hofmann, Dirk Nora, Pedro Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Portugal Friedrich-Alexander-Universität Erlangen-Nürnberg Germany

The term Stone-type duality often refers to a dual equivalence between a category of lattices or other partially ordered structures on one side and a category of topological structures on the other. This paper is part of a larger endeavour that aims to extend a web of Stone-type dualities from ordered to metric structures and, more generally, to quantale-enriched categories. In particular, we improve our previous work and show how certain duality results for categories of [0, 1]-enriched Priestley spaces and [0, 1]-enriched relations can be restricted to functions. In a broader context, we investigate the category of quantale-enriched Priestley spaces and continuous functors, with emphasis on those properties which identify the algebraic nature of the dual of this category. Copyright © 2020, The Authors. All rights reserved.

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Preface of the “Symposium on Mathematical Methods for Artificial Intelligence”

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AIP Conference Proceedings 2022年第1期2425卷

作者： Miranda, Francisco Abreu, Carlos Miranda, Daniel Rodrigues, Pedro Pereira Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun’Álvares Viana do Castelo 4900-347 Portugal Center for Research and Development in Mathematics and Applications (CIDMA) Department of Mathematics University of Aveiro Aveiro 3810-193 Portugal PROMETHEUS Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun’Álvares Viana do Castelo 4900-347 Portugal 2Ai – School of Technology IPCA Barcelos Portugal CINTESIS Faculty of Medicine University of Porto Portugal

Francisco Miranda, Carlos Abreu, Daniel Miranda, Pedro Pereira Rodrigues; Preface of the “Symposium on Mathematical Methods for Artificial Intelligence”, AIP Co

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Piercing of a boson star by a black hole

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Physical Review D 2022年第4期106卷 044030-044030页

作者： Vitor Cardoso Taishi Ikeda Zhen Zhong Miguel Zilhão Niels Bohr International Academy Niels Bohr Institute Blegdamsvej 17 2100 Copenhagen Denmark CENTRA Departamento de Física Instituto Superior Técnico—IST Universidade de Lisboa—UL Avenida Rovisco Pais 1 1049-001 Lisboa Portugal Dipartimento di Fisica “Sapienza” Universitá di Roma Piazzale Aldo Moro 5 00185 Roma Italy Departamento de Matemática da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal

New light fundamental fields are natural candidates for all or a fraction of dark matter. Self-gravitating structures of such fields might be common objects in the universe, and could comprise even galactic halos. These structures would interact gravitationally with black holes, a process of the utmost importance since it dictates their lifetime, the black hole motion, and possible gravitational radiation emission. Here, we study the dynamics of a black hole piercing through a much larger fully relativistic boson star, made of a complex minimally coupled massive scalar without self-interactions. As the black hole pierces through the bosonic structure, it is slowed down by accretion and dynamical friction, giving rise to gravitational-wave emission. Since we are interested in studying the interaction with large and heavy scalar structures, we consider mass ratios up to q∼10 and length ratios L∼62. Somewhat surprisingly, for all our simulations, the black hole accretes more than 95% of the boson star material, even if an initially small black hole collides with large velocity. This is a consequence of an extreme “tidal capture” process, which binds the black hole and the boson star together, for these mass ratios. We find evidence of a “gravitational atom” left behind as a product of the process.

关键词： Dark matter Gravitation Gravitational waves Numerical relativity

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