14,999 results match your criteria Asymptotic Analysis[Journal]

Model-based Bayesian inference under computer assisted balance-improving designs.

Stat Med 2022 Jun 24. Epub 2022 Jun 24.

Department of Statistics, Uppsala University, Uppsala, Sweden.

To improve covariate balance over a complete randomization, a number of methods have been proposed recently to utilize modern computational capabilities to find allocations with balance in observed covariates. Asymptotic inference on treatment effects based on these designs is more complicated than that under complete randomization, and this is why Fisher randomization tests often are suggested. This article suggests model-based Bayesian inference as a general method of inference in these designs, which can deal with complications such as arbitrary covariate balancing criteria and complex estimands. Read More

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Computational Advantage from a Quantum Superposition of Qubit Gate Orders.

Phys Rev Lett 2022 Jun;128(23):230503

University of Vienna, Faculty of Physics, Vienna Center for Quantum Science and Technology (VCQ), Boltzmanngasse 5, 1090 Vienna, Austria and Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria.

In an ordinary quantum algorithm the gates are applied in a fixed order on the systems. The introduction of indefinite causal structures allows us to relax this constraint and control the order of the gates with an additional quantum state. It is known that this quantum-controlled ordering of gates can reduce the query complexity in deciding a property of black-box unitaries with respect to the best algorithm in which the gates are applied in a fixed order. Read More

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Incubation characteristics, growth performance, carcass characteristics and meat quality of Saxonian Chicken and German Langshan bantam breeds in a free-range rearing system.

Vet Med Sci 2022 Jun 24. Epub 2022 Jun 24.

ZAFT e.V., Centre for Applied Research and Technology, Dresden, Germany.

Background/introduction: In the absence of evidence-based findings for Saxonian Chicken (SaChi) and German Langshan bantam (GLB), which are indigenous endangered German fancy chicken breeds, the objective of the present study was to characterise their growth performance and meat potential in an extensive free-range system METHODS: A total of 340 hatching eggs from SaChi and 439 eggs from GLB were provided by private breeders, from which 263 SaChi (77.3%) and 174 GLB (39.6%) hatched (p < 0. Read More

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Performance Analysis of Dual-Hop Hybrid RF-UOWC NOMA Systems.

Sensors (Basel) 2022 Jun 15;22(12). Epub 2022 Jun 15.

Faculty of Engineering at Shoubra, Benha University, Cairo 13511, Egypt.

The hybrid combination between underwater optical wireless communication (UOWC) and radio frequency (RF) is a vital demand for enabling communication through the air-water boundary. On the other hand, non-orthogonal multiple access (NOMA) is a key technology for enhancing system performance in terms of spectral efficiency. In this paper, we propose a downlink NOMA-based dual-hop hybrid RF-UOWC with decode and forward (DF) relaying. Read More

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Lightweight Design of Variable-Stiffness Cylinders with Reduced Imperfection Sensitivity Enabled by Continuous Tow Shearing and Machine Learning.

Materials (Basel) 2022 Jun 9;15(12). Epub 2022 Jun 9.

Faculty of Aerospace Engineering, Delft University of Technology, 2629 HS Delft, The Netherlands.

The present study investigates how to apply continuous tow shearing (CTS) in a manufacturable design parameterization to obtain reduced imperfection sensitivity in lightweight, cylindrical shell designs. The asymptotic nonlinear method developed by Koiter is applied to predict the post-buckled stiffness, whose index is constrained to be positive in the optimal design, together with a minimum design load. The performance of three machine learning methods, namely, Support Vector Machine, Kriging, and Random Forest, are compared as drivers to the optimization towards lightweight designs. Read More

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Cervical Cancer Prevention in the Era of the COVID-19 Pandemic.

Medicina (Kaunas) 2022 May 29;58(6). Epub 2022 May 29.

Department of Oncologic Gynecology and Obstetrics, The Center of Postgraduate Medical Education, 00-416 Warsaw, Poland.

: Cervical cancer (CC) is the fourth most common cause of cancer-related morbidity and mortality among women worldwide. CC prevention is based on screening and HPV vaccination. The COVID-19 pandemic has caused difficulties in implementing CC-preventative measures. Read More

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From Chaos to Ordering: New Studies in the Shannon Entropy of 2D Patterns.

Entropy (Basel) 2022 Jun 8;24(6). Epub 2022 Jun 8.

Department of Chemical Engineering, Engineering Faculty, Ariel University, P.O. Box 3, Ariel 407000, Israel.

Properties of the Voronoi tessellations arising from random 2D distribution points are reported. We applied an iterative procedure to the Voronoi diagrams generated by a set of points randomly placed on the plane. The procedure implied dividing the edges of Voronoi cells into equal or random parts. Read More

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Meta-Reinforcement Learning in Non-Stationary and Dynamic Environments.

IEEE Trans Pattern Anal Mach Intell 2022 Jun 23;PP. Epub 2022 Jun 23.

In recent years, the subject of deep reinforcement learning (DRL) has developed very rapidly, and is now applied in various fields, such as decision making and control tasks. However, artificial agents trained with RL algorithms require great amounts of training data, unlike humans that are able to learn new skills from very few examples. The concept of meta-reinforcement learning (meta-RL) has been recently proposed to enable agents to learn similar but new skills from a small amount of experience by leveraging a set of tasks with a shared structure. Read More

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Confidence intervals of mean residual life function in length-biased sampling based on modified empirical likelihood.

J Biopharm Stat 2022 Jun 23:1-16. Epub 2022 Jun 23.

Department of Mathematics and Statistics, Bowling Green State University, Bowling Green, Ohio, USA.

The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis. In this paper, we develop three procedures based on modified versions of empirical likelihood (EL) to construct confidence intervals of the MRL function with length-biased data. The asymptotic results corresponding to the procedures have been established. Read More

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On the meaning of Berry force for unrestricted systems treated with mean-field electronic structure.

J Chem Phys 2022 Jun;156(23):234107

Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

We show that the Berry force as computed by an approximate, mean-field electronic structure can be meaningful if properly interpreted. In particular, for a model Hamiltonian representing a molecular system with an even number of electrons interacting via a two-body (Hubbard) interaction and a spin-orbit coupling, we show that a meaningful nonzero Berry force emerges whenever there is spin unrestriction-even though the Hamiltonian is real-valued and formally the on-diagonal single-surface Berry force must be zero. Moreover, if properly applied, this mean-field Berry force yields roughly the correct asymptotic motion for scattering through an avoided crossing. Read More

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Centroidal Clustering of Noisy Observations by Using r th Power Distortion Measures.

Erdem Koyuncu

IEEE Trans Neural Netw Learn Syst 2022 Jun 22;PP. Epub 2022 Jun 22.

We consider the problem of clustering a dataset through multiple noisy observations of its members. The goal is to obtain a clustering that is as faithful to the clustering of the original dataset as possible. We propose a centroidal approach whose distortion measure is the sum of r th powers of the distances between the cluster center and the noisy observations. Read More

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Asymptotic behavior of the solutions for a stochastic SIRS model with information intervention.

Math Biosci Eng 2022 May;19(7):6940-6961

College of Mathematics and Systems Science, Shandong University of Science and Technology, Qingdao 266590, China.

In this paper, a stochastic SIRS epidemic model with information intervention is considered. By constructing an appropriate Lyapunov function, the asymptotic behavior of the solutions for the proposed model around the equilibria of the deterministic model is investigated. We show the average in time of the second moment of the solutions of the stochastic system is bounded for a relatively small noise. Read More

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Upper and lower bounds for the pull-in voltage and the pull-in distance for a generalized MEMS problem.

Math Biosci Eng 2022 May;19(7):6814-6840

Department of Mathematics, National Tsing Hua University, Hsinchu 300, Taiwan.

We study upper and lower bounds for the pull-in voltage and the pull-in distance for the one-dimensional prescribed mean curvature problem arising in MEMS $ \begin{equation*} \left \{\begin{array}{l} - \left( \frac{u^{ \prime } (x)}{\sqrt{1 +\left (u^{ \prime } (x)\right )^{2}}} \right)^{ \prime } = \frac{\lambda }{(1 -u)^{p}} , \ \ u <1 , \ \ -L 0 $ is a bifurcation parameter, and $ p, L > 0 $ are two evolution parameters. We further study monotonicity properties and asymptotic behaviors for the pull-in voltage and pull-in distance with respect to positive parameters $ p $ and $ L $. Read More

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Global dynamics of a diffusive phytoplankton-zooplankton model with toxic substances effect and delay.

Hong Yang

Math Biosci Eng 2022 Apr;19(7):6712-6730

School of Science, Jiangsu Ocean University, Lianyungang 222005, China.

This paper examines a diffusive toxic-producing plankton system with delay. We first show the global attractivity of the positive equilibrium of the system without time-delay. We further consider the effect of delay on asymptotic behavior of the positive equilibrium: when the system undergoes Hopf bifurcation at some points of delay by the normal form and center manifold theory for partial functional differential equations. Read More

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Classical and Bayesian inference of the weighted-exponential distribution with an application to insurance data.

Math Biosci Eng 2022 Apr;19(7):6551-6581

Department of Statistics, Mathematics and Insurance, Benha University, Benha 13511, Egypt.

This paper addresses asymmetric flexible two-parameter exponential model called the weighted exponential (WDEx) distribution. Some of its basic mathematical features are evaluated. Its hazard rate accommodates upside-down bathtub, decreasing, decreasing-constant, increasing, and increasing-constant shapes. Read More

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Mathematical modelling of unemployment as the effect of COVID-19 pandemic in middle-income countries.

Eur Phys J Spec Top 2022 Jun 17:1-8. Epub 2022 Jun 17.

Department of Mathematics,  College of Engineering and Technoogy, SRM Institute of Science and Technology, Chengalpattu District, Kattankulathur, Tamilnadu 603 203 India.

WHO (World Health Organization) has stamped Coronavirus disease 2019 (COVID-19) as a pandemic. This disease has affected most of the population in every aspect. One of those main aspects is the economical burden on the middle class and poor people. Read More

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Neural network interpolation operators optimized by Lagrange polynomial.

Neural Netw 2022 Jun 10;153:179-191. Epub 2022 Jun 10.

Department of Mathematics and Statistics, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada. Electronic address:

In this paper, we introduce a new type of interpolation operators by using Lagrange polynomials of degree r, which can be regarded as feedforward neural networks with four layers. The approximation rate of the new operators can be estimated by the (r+1)-th modulus of smoothness of the objective functions. By adding some smooth assumptions on the activation function, we establish two important inequalities of the derivatives of the operators. Read More

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Nonlinear control of a class of non-affine variable-speed variable-pitch wind turbines with radial-basis function neural networks.

ISA Trans 2022 May 12. Epub 2022 May 12.

Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB, Canada T2N 1N4.

Due to complicated dynamics, wind turbines' governing equations are subject to uncertainties and unknown disturbance sources. Despite uncertainties and disturbance sources, the paper's focus is to design an adaptive controller that enables trajectory-tracking with a zero-converging tracking error. As the main result of a zero tracking error, the turbine can operate at maximum power efficiency. Read More

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Accelerated Learning Control for Point-to-Point Tracking Systems.

IEEE Trans Neural Netw Learn Syst 2022 Jun 20;PP. Epub 2022 Jun 20.

In this study, we investigate the accelerated learning control schemes for point-to-point tracking systems (PTSs) with measurement noise. The asymptotic convergence of the generated input sequence has been a long-standing open issue for point-to-point tracking problems because there are infinite possible input candidates that can drive the system dynamics to track the desired reference at specified time instants. An accelerated gradient algorithm and its generalized version with a novel direction regulation matrix are proposed, with the learning gain is adaptively triggered by the practical tracking errors. Read More

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Evaluation of the Psychometric Properties of a Newly Developed Chinese Screening Tool for Speech Disorders in Patients With Parkinson's Disease.

Eval Health Prof 2022 Jun 18:1632787221108458. Epub 2022 Jun 18.

Institute of Allied Health Sciences, College of Medicine, 38026National Cheng Kung University, Tainan, Taiwan.

The study aimed to analyze the psychometric properties of a newly developed Chinese screening tool, the Chinese Version of the Speech Disorders in Parkinson's Disease Questionnaire (SDPD-C). The SDPD-C contains a 24-item questionnaire with four assessment domains. Overall, 93 patients with idiopathic Parkinson's disease (PD) (age 70. Read More

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Optimal Control and Stability Analysis of an SEIR Model with Infectious Force in Latent Period.

Comput Intell Neurosci 2022 15;2022:7596421. Epub 2022 Jun 15.

School of Science, Jiangnan University, Wuxi, Jiangsu 214122, China.

In this paper, an SEWIR epidemic model with the government control rate and infectious force in latent period is proposed. The conditions to the existence and uniqueness of disease-free and endemic equilibrium points in the SEWIR model are obtained. By using the Hurwitz criterion, the locally asymptotic stability of disease-free and endemic equilibrium points is proved. Read More

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Optimal criteria and their asymptotic form for data selection in data-driven reduced-order modelling with Gaussian process regression.

Philos Trans A Math Phys Eng Sci 2022 Aug 20;380(2229):20210197. Epub 2022 Jun 20.

Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.

We derive criteria for the selection of datapoints used for data-driven reduced-order modelling and other areas of supervised learning based on Gaussian process regression (GPR). While this is a well-studied area in the fields of active learning and optimal experimental design, most criteria in the literature are empirical. Here we introduce an optimality condition for the selection of a new input defined as the minimizer of the distance between the approximated output probability density function (pdf) of the reduced-order model and the exact one. Read More

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Asymptotic Survival of Genuine Multipartite Entanglement in Noisy Quantum Networks Depends on the Topology.

Phys Rev Lett 2022 Jun;128(22):220501

Departamento de Matemáticas, Universidad Carlos III de Madrid, E-28911, Leganés (Madrid), Spain.

The study of entanglement in multipartite quantum states plays a major role in quantum information theory and genuine multipartite entanglement signals one of its strongest forms for applications. However, its characterization for general (mixed) states is a highly nontrivial problem. We introduce a particularly simple subclass of multipartite states, which we term pair-entangled network (PEN) states, as those that can be created by distributing exclusively bipartite entanglement in a connected network. Read More

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Robust estimation of models for longitudinal data with dropouts and outliers.

J Appl Stat 2022 10;49(4):902-925. Epub 2020 Nov 10.

School of Data Science, Fudan University, Shanghai, People's Republic of China.

Missing data and outliers usually arise in longitudinal studies. Ignoring the effects of missing data and outliers will make the classical generalized estimating equation approach invalid. The longitudinal cohort study of rheumatoid arthritis patients was designed to investigate whether the Health Assessment Questionnaire score was associated with baseline covariates and changed with time. Read More

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November 2020

Reliability analysis of multicomponent stress-strength reliability from a bathtub-shaped distribution.

J Appl Stat 2022 8;49(1):122-142. Epub 2020 Aug 8.

Department of Mathematics, Indian Institute of Technology Patna, Bihta, India.

In this paper, inference for a multicomponent stress-strength model is studied. When latent strength and stress random variables follow a bathtub-shaped distribution and the failure times are Type-II censored, the maximum likelihood estimate of the multicomponent stress-strength reliability (MSR) is established when there are common strength and stress parameters. Approximate confidence interval is also constructed by using the asymptotic distribution theory and delta method. Read More

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Statistical inferences for single-index models with measurement errors.

J Appl Stat 2021 24;48(6):1033-1052. Epub 2020 Apr 24.

School of Science, Nanjing University of Science and Technology, Nanjing, People's Republic of China.

An important factor in house prices is its location. However, measurement errors arise frequently in the process of observing variables such as the latitude and longitude of the house. The single-index models with measurement errors are used to study the relationship between house location and house price. Read More

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A skew factor analysis model based on the normal mean-variance mixture of Birnbaum-Saunders distribution.

J Appl Stat 2020 6;47(16):3007-3029. Epub 2020 Jan 6.

Institute of Statistics, National Chung Hsing University, Taichung, Taiwan.

This paper presents a robust extension of factor analysis model by assuming the multivariate normal mean-variance mixture of Birnbaum-Saunders distribution for the unobservable factors and errors. A computationally analytical EM-based algorithm is developed to find maximum likelihood estimates of the parameters. The asymptotic standard errors of parameter estimates are derived under an information-based paradigm. Read More

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January 2020

On bias reduction estimators of skew-normal and skew-t distributions.

J Appl Stat 2020 9;47(16):3030-3052. Epub 2020 Jan 9.

Department of Statistics, University of Isfahan, Isfahan, Iran.

A particular concerns of researchers in statistical inference is bias in parameters estimation. Maximum likelihood estimators are often biased and for small sample size, the first order bias of them can be large and so it may influence the efficiency of the estimator. There are different methods for reduction of this bias. Read More

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January 2020

Estimating the turning point of the log-logistic hazard function in the presence of long-term survivors with an application for uterine cervical cancer data.

Patrick Borges

J Appl Stat 2021 3;48(2):203-213. Epub 2020 Feb 3.

Departamento de Estatística, Universidade Federal do Espírito Santo, Vitória, Brazil.

The hazard function plays an important role in cancer patient survival studies, as it quantifies the instantaneous risk of death of a patient at any given time. Often in cancer clinical trials, unimodal hazard functions are observed, and it is of interest to detect (estimate) the turning point (mode) of hazard function, as this may be an important measure in patient treatment strategies with cancer. Moreover, when patient cure is a possibility, estimating cure rates at different stages of cancer, in addition to their proportions, may provide a better summary of the effects of stages on survival rates. Read More

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February 2020

Quantile regression for general spatial panel data models with fixed effects.

J Appl Stat 2020 13;47(1):45-60. Epub 2019 Jun 13.

Department of Mathematics and Statistics, Hang Seng Management College, Hong Kong, People's Republic of China.

This paper considers the quantile regression model with both individual fixed effect and time period effect for general spatial panel data. Fixed effects quantile regression estimators based on instrumental variable method will be proposed. Asymptotic properties of the proposed estimators will be developed. Read More

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