检索结果-内蒙古大学图书馆

arXiv 2023年

作者： Guo, Chu Poletti, Dario Arad, Itai Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Engineering Product Development Pillar Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Centre for Quantum Technologies National University of Singapore 117543 Singapore MajuLab CNRS-UNS-NUS-NTU International Joint Research Unit UMI 3654 Singapore Faculty of Physics Technion Haifa3200003 Israel

Belief propagation is a well-studied algorithm for approximating local marginals of multivariate probability distribution over complex networks, while tensor network states are powerful tools for quantum and classical many-body problems. Building on a recent connection between the belief propagation algorithm and the problem of tensor network contraction, we propose a block belief propagation algorithm for contracting two-dimensional tensor networks and approximating the ground state of 2D systems. The advantages of our method are three-fold: 1) the same algorithm works for both finite and infinite systems;2) it allows natural and efficient parallelization;3) given its flexibility it would allow to deal with different unit cells. As applications, we use our algorithm to study the 2D Heisenberg and transverse Ising models, and show that the accuracy of the method is on par with state-of-the-art results. Copyright © 2023, The Authors. All rights reserved.

关键词： Tensors

来源：评论

学校读者我要写书评

暂无评论

Identification of binary neutron star mergers in gravitational-wave data using object-detection machine learning models

引用

Physical Review D 2022年第8期106卷 084059-084059页

作者： João Aveiro Felipe F. Freitas Márcio Ferreira Antonio Onofre Constança Providência Gonçalo Gonçalves José A. Font CFisUC Department of Physics University of Coimbra 3004-516 Coimbra Portugal Departamento de Física da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal Centro de Física das Universidades do Minho e do Porto (CF-UM-UP) Universidade do Minho 4710-057 Braga Portugal LIP Department of Physics University of Coimbra 3004-516 Coimbra Portugal Departamento de Astronomía y Astrofísica Universitat de València Dr. Moliner 50 46100 Burjassot (València) Spain Observatori Astronòmic Universitat de València Catedrático José Beltrán 2 46980 Paterna (València) Spain

We demonstrate the application of the YOLOv5 model, a general purpose convolution-based object detection model, in the task of detecting binary neutron star coalescence events from gravitational-wave data of current generation interferometer detectors. We also present a thorough explanation of the synthetic data generation and preparation tasks based on approximant waveform models used for the model training, validation and testing steps. Using this approach, we achieve mean average precision [0.50] values of 0.945 for a single class validation dataset and as high as 0.978 for test datasets. Moreover, the trained model is successful in identifying the GW170817 event in the LIGO H1 detector data. The identification of this event is also possible for the LIGO L1 detector data with an additional preprocessing step, without the need of removing the large glitch in the final stages of the inspiral. The detection of the GW190425 event is less successful, which attests to performance degradation with the signal-to-noise ratio. Our study indicates that the YOLOv5 model is an interesting approach for first-stage detection alarm pipelines.

关键词： Gravitational wave detection Binary stars Neutron stars & pulsars Gravitational wave detectors

来源：评论

学校读者我要写书评

暂无评论

The main vertices of a star set and related graph parameters

arXiv

引用

arXiv 2020年

作者： Andelić, Milica Cardoso, Domingos M. Simić, Slobodan K. Stanić, Zoran Department of Mathematics Kuwait University Safat13060 Kuwait Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Campus de Santiago Aveiro3810-193 Portugal Mathematical Institute of SANU Belgrade Serbia Faculty of Mathematics University of Belgrade Studentski trg 16 Belgrade11 000 Serbia

A vertex v ∈ V (G) is called λ-main if it belongs to a star set X ⊂ V (G) of the eigenvalue λ of a graph G and this eigenvalue is main for the graph obtained from G by deleting all the vertices in X \ {v};otherwise, v is λ-non-main. Some results concerning main and non-main vertices of an eigenvalue are deduced. For a main eigenvalue λ of a graph G, we introduce the minimum and maximum number of λ-main vertices in some λ-star set of G as new graph invariant parameters. The determination of these parameters is formulated as a combinatorial optimization problem based on a simplex-like approach. Using these and some related parameters we develop new spectral tools that can be used in the research of the isomorphism problem. Examples of graphs for which the maximum number of λ-main vertices coincides with the cardinality of a λ-star set are *** Codes 2020: 05C50, 05C60, 90C08 © 2020, CC BY-NC-ND.

关键词： Stars

来源：评论

学校读者我要写书评

暂无评论

Personalized and context-aware decision support system for diabetes therapeutics

引用

AIP Conference Proceedings 2024年第1期3094卷

作者： Débora Amorim Carlos Abreu Francisco Miranda ADiT-LAB Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun’Álvares 4900-347 Viana do Castelo Portugal Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun’Álvares 4900-347 Viana do Castelo Portugal Center for Research and Development in Mathematics and Applications (CIDMA) Department of Mathematics University of Aveiro 3810-193 Aveiro Portugal proMetheus Instituto Politécnico de Viana do Castelo Rua Escola Industrial e Comercial de Nun’Álvares 4900-347 Viana do Castelo Portugal

Personalized recommendations for diabetes therapy can be highly beneficial but complex to make and time-consuming for patients and healthcare professionals. Therefore, we propose a decision support system to help patients and healthcare professionals to make decisions to improve treatments based on the patient’s daily life data. The proposed solution allows the collection of patients’ data related to their glycemic profile, insulin doses, carbohydrate intake, physical activity, and patient weight. This data provides information for a case-based reasoning system to predict postprandial blood glucose allowing the calculation improvement of bolus insulin. This decision support system aims to reduce patients’ hypo and hyperglycemic episodes and improve the patients’ time in range.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Spontaneous scalarization of a conducting sphere in Maxwell-scalar models

引用

Physical Review D 2021年第4期103卷 044019-044019页

作者： Carlos A. R. Herdeiro Taishi Ikeda Masato Minamitsuji Tomohiro Nakamura Eugen Radu 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 Centro de Astrofísica e Gravitação—CENTRA Departamento de Física Instituto Superior Técnico—IST Universidade de Lisboa—UL Av. Rovisco Pais 1 1049-001 Lisboa Portugal Dipartimento di Fisica “Sapienza” Universitá di Roma Piazzale Aldo Moro 5 00185 Roma Italy Department of Physics Nagoya University Nagoya 464-8602 Japan

We study the spontaneous scalarization of a standard conducting charged sphere embedded in Maxwell-scalar models in flat spacetime, wherein the scalar field ϕ is nonminimally coupled to the Maxwell electrodynamics. This setup serves as a toy model for the spontaneous scalarization of charged (vacuum) black holes in Einstein-Maxwell-scalar (generalized scalar-tensor) models. In the Maxwell-scalar case, unlike the black hole cases, closed-form solutions exist for the scalarized configurations. We compute these configurations for three illustrations of nonminimal couplings: one that exactly linearizes the scalar field equation, and the remaining two that produce nonlinear continuations of the first one. We show that the former model leads to a runaway behavior in regions of the parameter space and neither the Coulomb nor the scalarized solutions are stable in the model; but the latter models can heal this behavior producing stable scalarized solutions that are dynamically preferred over the Coulomb one. This parallels reports on black hole scalarization in the extended-scalar-Gauss-Bonnet models. Moreover, we analyze the impact of the choice of the boundary conditions on the scalarization phenomenon. Dirichlet and Neumann boundary conditions accommodate both (linearly) stable and unstable parameter space regions, for the scalar-free conducting sphere; but radiative boundary conditions always yield an unstable scalar-free solution and preference for scalarization. Finally, we perform numerical evolution of the full Maxwell-scalar system, following dynamically the scalarization process. They confirm the linear stability analysis and reveal that the scalarization phenomenon can occur in qualitatively distinct ways.

关键词： Gravitation

来源：评论

学校读者我要写书评

暂无评论

Lyapunov-type inequality for a fractional boundary value problem with natural conditions

引用

SeMA Journal 2018年第1期75卷 157-162页

作者： Guezane-Lakoud, Assia Khaldi, Rabah Torres, Delfim F. M. Laboratory of Advanced Materials Department of Mathematics Badji Mokhtar-Annaba University P.O. Box 12 Annaba 23000 Algeria Department of Mathematics Center for Research and Development in Mathematics and Applications (CIDMA) University of Aveiro Aveiro 3810-193 Portugal

We derive a new Lyapunov type inequality for a boundary value problem involving both left Riemann–Liouville and right Caputo fractional derivatives in presence of natural conditions. Application to the corresponding ... 详细信息

关键词： Eigenvalue problem Fractional calculus Lyapunov inequality

来源：评论

学校读者我要写书评

暂无评论

On the spectra of g-circulant matrices and applications

arXiv

引用

arXiv 2019年

作者： Andrade, Enide Arrieta, Luis Robbiano, María CIDMA-Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Aveiro3810-193 Portugal Departamento de Matemáticas Universidad Católica Del Norte Av. Angamos 0610 Antofagasta Chile

A g-circulant matrix of order n is defined as a matrix of order n where each row is a right cyclic shift in g-places to the preceding row. Using number theory, certain nonnegative g-circulant real matrices are constructed. In particular, it is shown that spectra with sufficient conditions so that it can be the spectrum of a real g-circulant matrix is not a spectrum with sufficient conditions so that it can be the spectrum of a real circulant matrix of the same order. The obtained results are applied to Nonnegative Inverse Eigenvalue Problem to construct nonnegative, g-circulant matrices with given appropriated spectrum. Moreover, nonnegative g-circulant matrices by blocks are also studied and in this case, their orders can be a multiple of a prime number. Copyright © 2019, The Authors. All rights reserved.

关键词： Matrix algebra

来源：评论

学校读者我要写书评

暂无评论

Traveling wave solutions of some important Wick-type fractional stochastic nonlinear partial differential equations∗

arXiv

引用

arXiv 2019年

作者： Kim, Hyunsoo Sakthivel, Rathinasamy Debbouche, Amar Torres, Delfim F.M. Department of Mathematics Sungkyunkwan University Suwon16419 Department of Applied Mathematics Bharathiar University Coimbatore641 046 India Department of Mathematics Guelma University Guelma24000 Algeria CIDMA Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Aveiro3810-193 Portugal

In this article, exact traveling wave solutions of a Wick-type stochastic nonlinear Schrödinger equation and of a Wick-type stochastic fractional Regularized Long Wave-Burgers (RLW-Burgers) equation have been obtained by using an improved computational method. Specifically, the Hermite transform is employed for transforming Wick-type stochastic nonlinear partial differential equations into deterministic nonlinear partial differential equations with integral and fraction order. Furthermore, the required set of stochastic solutions in the white noise space is obtained by using the inverse Hermite transform. Based on the derived solutions, the dynamics of the considered equations are performed with some particular values of the physical parameters. The results reveal that the proposed improved computational technique can be applied to solve various kinds of Wick-type stochastic fractional partial differential equations. Copyright © 2019, The Authors. All rights reserved.

关键词： Solitons

来源：评论

学校读者我要写书评

暂无评论

POS0950 ARE THERE GENDER DIFFERENCES IN AXIAL SPONDYLOARTHRITIS: DATA FROM A PORTUGUESE SPONDYLOARTHRITIS COHORT

引用

Annals of the Rheumatic Diseases 2021年 80卷 738-738页

作者： A.R. Cunha R. Aguiar M.J. Santos V. Afreixo A. Barcelos Centro Hospitalar do Baixo Vouga Rheumatology Aveiro Portugal Hospital Garcia de Orta Rheumatology Almada Portugal University of Aveiro Department of Mathematics and CIDMA - Center for Research & Development in Mathematics and Applications Aveiro Portugal University NOVA Lisbon NOVA National School of Public Health Public Health Research Centre Lisbon Portugal University NOVA Lisbon Comprehensive Health Research Center (CHRC) Lisbon Portugal

Background: Historically, axial spondyloarthritis (particularly ankylosing spondylitis) was considered a men's disease and has been under-recognized in women. Emerging evidence reveals gender differences in patophysiology, disease presentation and therapeutic efficacy. Objectives: To determine if there are differences between genders in a Portuguese cohort of patients with axSpA as regards clinical manifestations, disease activity, functional capacity, patient related outcomes and radiographic findings. Methods: Patients with ≥18 years fulfilling the ASAS- Assessment of Spondyloarthritis International Society classification criteria for axSpA and registered in the electronic national database- *** were included in a multicentric cross-sectional study. Sociodemographic data, clinical features and radiographic findings were collected from the first record in ***. These variables were compared between genders using Mann-Whitney test and Chi-Square test. Variables with a significant association with group variable (gender) were considered in the multiple variable analysis to adjust the gender effect on the outcome variables. Results: A total of 1995 patients were included, 1114 (55.9%) men and 881 (44.1%) women. Men had a lower median age at onset of disease (25.1 vs 28.4, p=0.000) and median age at diagnosis (26.9 vs 30.4, p=0.000) and were more frequently smokers (32.1% vs 15.7%, p=0.000). Comparing to women, men had worse BASMI scores (4.0 vs 3.4, p=0.000), higher levels of CPR (10.5 vs 6.9, p=0.000) and were more often HLA-B27 positive (67.8% vs 54%, p=0.000). In univariable analysis, sacroiliitis on radiograph or/and MRI (95.5% vs 91.7%, p=0.04) was more common in men, however that wasn't confirmed in multivariable analysis. In contrast, women more frequently had more inflammatory bowel disease (8.8% vs 4.9%, p=0,004), higher levels of ESR (25.0 vs 21.0, p=0.003) and worse PROs- BASDAI (5.7 vs 4.5, p=0.000), PGA (60.0 vs 55.0, p=0.000) and fatigue (6.2 vs

关键词：

来源：评论

学校读者我要写书评

暂无评论

Multifield, Multifrequency Bosonic Stars and a Stabilization Mechanism

引用

Physical Review Letters 2021年第24期126卷 241105-241105页

作者： Nicolas Sanchis-Gual Fabrizio Di Giovanni Carlos Herdeiro Eugen Radu José A. Font 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 Centro de Astrofísica e Gravitação–CENTRA Departamento de Física Instituto Superior Técnico–IST Universidade de Lisboa–UL Avenida Rovisco Pais 1 1049-001 Lisboa Portugal Departamento de Astronomía y Astrofísica Universitat de València Dr. Moliner 50 46100 Burjassot (València) Spain Observatori Astronòmic Universitat de València C/ Catedrático José Beltrán 2 46980 Paterna (València) Spain

Scalar bosonic stars (BSs) stand out as a multipurpose model of exotic compact objects. We enlarge the landscape of such (asymptotically flat, stationary, everywhere regular) objects by considering multiple fields (possibly) with different frequencies. This allows for new morphologies and a stabilization mechanism for different sorts of unstable BSs. First, any odd number of complex fields, yields a continuous family of BSs departing from the spherical, equal frequency, ℓ-BSs. As the simplest illustration, we construct the ℓ=1 BSs family, that includes several single-frequency solutions, including even parity (such as spinning BSs and a toroidal, static BS) and odd parity (a dipole BS) limits. Second, these limiting solutions are dynamically unstable, but can be stabilized by a hybrid-ℓ construction: adding a sufficiently large fundamental ℓ=0 BS of another field, with a different frequency. Evidence for this dynamical robustness is obtained by nonlinear numerical simulations of the corresponding Einstein-(complex, massive) Klein-Gordon system, both in formation and evolution scenarios, and a suggestive correlation between stability and energy distribution is observed. Similarities and differences with vector BSs are anticipated.

关键词： General relativity General relativity equations & solutions Numerical relativity

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：