检索结果-内蒙古大学图书馆

Antithetic Multilevel Particle Filters

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Jasra, Ajay Maama, Mohamed Ombao, Hernando Applied Mathematics and Computational Science Program United States Statistics Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

In this paper we consider the filtering of partially observed multi-dimensional diffusion processes that are observed regularly at discrete times. This is a challenging problem which requires the use of advanced numerical schemes based upon time-discretization of the diffusion process and then the application of particle filters. Perhaps the state-of-the-art method for moderate dimensional problems is the multilevel particle filter of [12]. This is a method that combines multilevel Monte Carlo and particle filters. The approach in that article is based intrinsically upon an Euler discretization method. We develop a new particle filter based upon the antithetic truncated Milstein scheme of [10]. We show that for a class of diffusion problems, for ϵ > 0 given, that the cost to produce a mean square error (MSE) in estimation of the filter, of O(ϵ2) is O(ϵ−2 log(ϵ)2). In the case of multidimensional diffusions with non-constant diffusion coefficient, the method of [12] has a cost of O(ϵ−2.5) to achieve the same MSE. We support our theory with numerical results in several examples. Copyright © 2023, The Authors. All rights reserved.

关键词： Mean square error

DIAMETER AND CONNECTIVITY OF FINITE SIMPLE GRAPHS II

学校读者我要写书评

暂无评论

arXiv 2024年

作者： T., Hibi S.S., Madani Department of Pure and Applied Mathematics Graduate School of Information Science and Technology Osaka University Suita Osaka565-0871 Japan Department of Mathematics and Computer Science Amirkabir University of Technology Tehran Iran School of Mathematics Institute for Research in Fundamental Sciences Tehran Iran

Let G be a finite simple non-complete connected graph on [n] = {1, . . ., n} and κ(G) ≥ 1 its vertex connectivity. Let f (G) denote the number of free vertices of G and diam(G) the diameter of G. The final goal of this paper is to determine all sequences of integers (n, f, d, k) with n ≥ 8, f ≥ 0, d ≥ 2 and k ≥ 1 for which there exists a finite simple non-complete connected graph on [n] with f = f (G), d = diam(G) and k = κ(G).MSC Codes 05C12, 05C40 Copyright © 2024, The Authors. All rights reserved.

关键词： Graphic methods

Predicting Conversion of Mild Cognitive Impairment to Alzheimer’s Disease by Modelling Healthy Ageing Trajectories

学校读者我要写书评

暂无评论

Predicting Conversion of Mild Cognitive Impairment to Alzhei...

IEEE International Symposium on Biomedical Imaging

作者： Yiran Wei Xi Chen Carola-Bibiane Schönlieb Stephen J. Price Chao Li Department of Clinical Neurosciences University of Cambridge Department of Computer Science University of Bath Department of Applied Mathematics and Theoretical Physics University of Cambridge

Alzheimer’s disease (AD) is a heterogeneous type of dementia. Mild cognitive impairment (MCI) is the early stage of cognitive decline before AD. Predicting the MCI-to-AD conversion remains challenging due to the heterogeneity of patients. Previous evidence shows that the brain network generated from diffusion MRI promises to classify dementia. However, the limited availability of diffusion MRI obstructs the training of deep learning models. Here, we firstly develop a cross-modal approach to generate brain networks from anatomical MRI under the guidance of diffusion MRI. We then construct the healthy ageing trajectories of controls with a generative model. Finally, we design a recurrent neural networks-based approach to model the longitudinal deviation of patients’ brain networks from the healthy ageing trajectory. Numerical results show that the proposed methods outperform the benchmarks in the prediction task. We also visualize the model interpretation to explain the prediction and identify abnormal changes in white matter tracts.

关键词：

Parameterised Approximation of the Fixation Probability of the Dominant Mutation in the Multi-Type Moran Process

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Goldberg, Leslie Ann Roth, Marc Schwarz, Tassilo Constantin Department of Computer Science University of Oxford United Kingdom Department of Applied Mathematics and Theoretical Physics University of Cambridge United Kingdom

The multi-type Moran process is an evolutionary process on a connected graph G in which each vertex has one of k types and, in each step, a vertex v is chosen to reproduce its type to one of its neighbours. The probability of a vertex v being chosen for reproduction is proportional to the fitness of the type of v. So far, the literature was almost solely concerned with the 2-type Moran process in which each vertex is either healthy (type 0) or a mutant (type 1), and the main problem of interest has been the (approximate) computation of the so-called fixation probability, i.e., the probability that eventually all vertices are mutants. In this work we initiate the study of approximating fixation probabilities in the multi-type Moran process on general graphs. Our main result is an FPTRAS (fixed-parameter tractable randomised approximation scheme) for computing the fixation probability of the dominant mutation;the parameter is the number of types and their fitnesses. In the course of our studies we also provide novel upper bounds on the expected absorption time, i.e., the time that it takes the multi-type Moran process to reach a state in which each vertex has the same type. © 2023, CC BY.

关键词： Cell proliferation

On the Assessment of Electrostatic and Seismic Conditions When Using Autonomous Groups of Rescue Robots 25

学校读者我要写书评

暂无评论

On the Assessment of Electrostatic and Seismic Conditions Wh...

25th IEEE International Conference of Young Professionals in Electron Devices and Materials, EDM 2024

作者： Frolov, Ivan N. Kudryavtsev, Nikolay G. Kudin, Dmitry V. Safonova, Varvara Y. Network and System Administration Department Gorno-Altaisk State University Gorno-Altaisk Russia Department of Mathematics Physics and Computer Science Gorno-Altaisk State University Gorno-Altaisk Russia Geophysical Monitoring Sector Geophysical Center The Russian Academy of Sciences Moscow Russia Department of Economics Tourism and Applied Informatics Gorno-Altaisk State University Gorno-Altaisk Russia

ISBN: (纸本)9798350389234

The purpose of this work is to study the need for the use and methods of implementing technical systems that allow automatic assessment of the electrostatic situation and seismic activity during rescue operations using groups of mobile robots in natural disaster zones. The authors consider the principles of operation and technical implementation of a hybrid monitoring system, one of the components of which is made on the basis of an electrostatic flux meter and allows, in real time over a local time period, to predict the approach and evaluate the intensity of the observed lightning event, based on counting the number of recorded lightning discharge signals and the degree of change their amplitudes per unit time. The seismic component of the hybrid monitoring system under consideration is created on the basis of an infrasonic sensor made using a MEMS microphone, structurally placed inside an acoustic Helmholtz resonator. In this work, the authors present the results of tests of a prototype of the described system, developed and implemented in the robotics laboratory of Gorno-Altaysk State University. The work also presents the results of measurement experiments carried out at the university test site, provides and analyzes examples of signals of variations in the strength of the atmospheric electric field during thunderstorm events and acoustic emission signals recorded in the upper part of the infrasound range at times of increased seismic activity. © 2024 IEEE.

关键词： Lightning

Unbiased Approximations for Stationary Distributions of McKean-Vlasov SDEs

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Awadelkarim, Elsiddig Chada, Neil K. Jasra, Ajay Applied Mathematics and Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Department of Mathematics City University of Hong Kong Hong Kong School of Data Science The Chinese University of Hong Kong Shenzhen Shenzhen China

We consider the development of unbiased estimators, to approximate the stationary distribution of Mckean-Vlasov stochastic differential equations (MVSDEs). These are an important class of processes, which frequently appear in applications such as mathematical finance, biology and opinion dynamics. Typically the stationary distribution is unknown and indeed one cannot simulate such processes exactly. As a result one commonly requires a time-discretization scheme which results in a discretization bias and a bias from not being able to simulate the associated stationary distribution. To overcome this bias, we present a new unbiased estimator taking motivation from the literature on unbiased Monte Carlo. We prove the unbiasedness of our estimator, under assumptions. In order to prove this we require developing ergodicity results of various discrete time processes, through an appropriate discretization scheme, towards the invariant measure. Numerous numerical experiments are provided, on a range of MVSDEs, to demonstrate the effectiveness of our unbiased estimator. Such examples include the Currie-Weiss model, a 3D neuroscience model and a parameter estimation problem. © 2024, CC BY-NC-SA.

关键词： Stochastic systems

Child Tracking and Prediction of Violence on Children In Social Media Using Natural Language Processing and Machine Learning 1

学校读者我要写书评

暂无评论

22nd International Conference on Artificial Intelligence and Soft Computing, ICAISC 2023

作者： Nallakaruppan, M.K. Srivastava, Gautam Gadekallu, Thippa Reddy Reddy, Praveen Kumar Krishnan, Sivarama Polap, Dawid School of Information Technology and Engineering Vellore Institute of Technology Vellore India Department of Mathematics and Computer Science Brandon University Brandon Canada School of Information Technology and Engineering Vellore Institute of Technology Department of Electrical and Computer Engineering Lebanese American University Lebanon Zhongda Group Zhejiang Jiaxing314312 China Faculty of Applied Mathematics Silesian University of Technology Kaszubska 23 Gliwice44-100 Poland

ISBN: (数字)9783031425059

ISBN: (纸本)9783031425042

Crimes against children are a direct threat to the world of tomorrow. The future of the world is in the hands of children who are the real wealth of mankind. The challenge for society is to address and handle challenges against children such as sexual abuse, trafficking, child labour, and harassment. Even though measures are taken by several governments globally, violence against children is an evident day-to-day process. This becomes the most challenging issue in the post-Internet era, where organized crime against children takes place around the world through a targeted group of people through virtual private networks and the dark web. What comes next is the emergence of social media, which provides an opportunity for these criminals to harm children globally through powerful social networks [15]. The existing methods focus on classifiers that do not work across multiple keywords [6] to look for sentiment analysis regarding a single classifier. There are only a few works that address the issue and these methods do not employ the multi-classification model [2]. In this paper, we propose a model which includes the Twitter API, the APIFY web scraper framework, as well as the VADER semantic analyzer in Python which possesses Decision tree analysis of sentiment prediction. The proposed work provides 99.6904% accuracy and predicts the classification of sentiment analysis. Our work has novelty in attribute selection, child trade, and violence analysis in social media and prediction of classification accuracy using the Decision Tree algorithm. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Machine learning

Singleton Coalition Graph Chains

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Bakhshesh, Davood Henning, Michael A. Pradhan, Dinabandhu Department of Computer Science University of Bojnord Bojnord Iran Department of Mathematics and Applied Mathematics University of Johannesburg Auckland Park2006 South Africa Dhanbad India

Let G be graph with vertex set V and order n = |V|. A coalition in G is a combination of two distinct sets, A ⊆ V and B ⊆ V, which are disjoint and are not dominating sets of G, but their union A ∪ B is a dominating set of G. A coalition partition of G is a partition P = {S1, ⋯ , Sk} of its vertex set V, where each set Si∈ P is either a dominating set of G with only one vertex, or it is not a dominating set but forms a coalition with some other set Sj∈ P. The coalition number C(G) is the maximum cardinality of a coalition partition of G. To represent a coalition partition P of G, a coalition graph CG(G,P) is created, where each vertex of the graph corresponds to a member of P and two vertices are adjacent if and only if their corresponding sets form a coalition in G. A coalition partition P of G is a singleton coalition partition if every set in P consists of a single vertex. If a graph G has a singleton coalition partition, then G is referred to as a singleton-partition graph. A graph H is called a singleton coalition graph of a graph G if there exists a singleton coalition partition P of G such that the coalition graph CG(G,P) is isomorphic to H. A singleton coalition graph chain with an initial graph G1is defined as the sequence G1→ G2→ G3→⋯ where all graphs Giare singleton-partition graphs, and CG(Gi, Γ1) = Gi+1, where Γ1represents a singleton coalition partition of Gi. In this paper, we address two open problems posed by Haynes et al. We characterize all graphs G of order n and minimum degree δ(G) = 2 such that C(G) = n. Additionally, we investigate the singleton coalition graph chain starting with graphs G where δ(G) ≤ 2. © 2023, CC BY.

关键词： Graphic methods

Modeling and numerical analysis of nanoliquid (titanium oxide, graphene oxide) flow viscous fluid with second order velocity slip and entropy generation

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2021年第3期34卷 17-25页

作者： M.Ijaz Khan Seifedine Kadry Yuming Chu M.Waqas Department of Mathematics Riphah International UniversityFaisalabad CampusFaisalabad 38000Pakistan Department of Mathematics and Computer Science Beirut Arab UniversityBeirutLebanon Department of Mathematics Huzhou UniversityHuzhou 313000China Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering Changsha University of Science&TechnologyChangsha 410114China NUTECH School of Applied Sciences and Humanities National University of TechnologyIslamabad 44000Pakistan

The prime objective of the present communication is to examine the entropy-optimized second order velocity slip Darcy–Forchheimer hybrid nanofluid flow of viscous material between two rotating *** conducting flow is considered and saturated through Darcy–Forchheimer *** the disks are rotating with different angular frequencies and stretches with different *** graphene oxide and titanium dioxide are considered for hybrid nanoparticles and water as a continuous phase *** heating,heat generation/absorption and viscous dissipation effects are incorporated in the mathematical modeling of energy ***,binary chemical reaction with activation energy is *** total entropy rate is calculated in the presence of heat transfer irreversibility,fluid friction irreversibility,Joule heating irreversibility,porosity irreversibility and chemical reaction irreversibility through thermodynamics second *** nonlinear governing equations are first converted into ordinary differential equations through implementation of appropriate similarity transformations and then numerical solutions are calculated through Built-in-Shooting *** of sundry flow variables on the entropy generation rate,velocity,concentration,Bejan number,temperature are discussed graphically for both graphene oxide and titanium dioxide hybrid *** engineering interest like skin friction coefficient and Nusselt number are computed numerically and presented through *** is noticed from the obtained results that entropy generation rate and Bejan number have similar effects versus diffusion *** entropy generation rate is more against the higher Brinkman number.

关键词： Darcy-Forchheimer porous medium Titanium dioxide and graphene oxide nanoparticles Second order velocity slip Convective boundary condition Activation energy Heat generation/absorption