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Xiaofeng Xue

Publications and source records attributed to Xiaofeng Xue.

At least 19 recordsLinked to original sources
arXiv2026

Invariance principles for additive functionals of voter models

In this paper, we prove an invariance principle for the additive functionals of a family of voter models, which include the nearest-neighbor cases on $d$-dimensional lattices for $d$ at least $5$ or on regular trees with degree at least $3$ and some long-range cases on lattices as special examples. The proof of our main result extends a martingale decomposition method, where the Kolmogorov backward equation and the duality relationship between the voter model and the coalescing random walk play the key roles.

math.PR↗
arXiv2026

Inhomogeneous central limit theorems for the voter model occupation times

In this paper, we extend the functional central limit theorems for the occupation times of the voter models on lattices given in Xue2026 to the case where the initial distribution is a spatially inhomogeneous product measure. The duality relationship between the voter model and the coalescing random walk and the Donsker's invariance principle of the simple random walk play the key roles in the proofs of our main results.

math.PR↗
arXiv2025

Experimental Investigation of Skew Wind Effects on Vortex-Induced Vibration of Typical Bridge Decks

This study explores the skew wind effects on vortex-induced vibration (VIV) of two typical bridge decks-a closed-box girder and a twin-edge girder-through spring-suspended oblique section model tests. Experiments were conducted at various wind yaw angles and angles of attack. Results indicate that VIV amplitudes and lock-in ranges exhibit a clear variation with yaw angles, rendering the Independence Principle (IP) unsuitable for these configurations. A heave-torsion coupling phenomenon was observed in both heaving and torsional VIV, attributed to the eccentricity of the center of gravity due to asymmetric end segments. A novel numerical algorithm was introduced to correct peak VIV amplitudes for variations in structural mass-damping parameters across yaw angles. The most unfavorable VIV responses occurred under skew wind conditions, with maximum amplitudes increasing by approximately 20.1 percent for heaving VIV and 179.8 percent for torsional VIV in the closed-box girder, and by 3.9 percent for heaving VIV in the twin-edge girder, relative to normal wind conditions.

physics.app-ph↗
arXiv2025

Stationary fluctuations for occupation times of the long-range voter models on lattices

In this paper, we are concerned with the long-range voter model on lattices. We prove a stationary fluctuation theorem for the occupation time of the model under a proper time-space scaling. In several cases, the fluctuation limits are driven by fractional Brownian motions with Hurst parameters in $(1/2, 1)$. The proof of our main result utilizes the martingale decomposition strategy introduced in \cite{Kipnis1987}. A local central limit theorem of the long-range random walk, the duality relationship between the model and the long-range coalescing random walk and a fluctuation theorem of the empirical density field of the model play the key roles in the proof.

math.PR↗
arXiv2025

Moderate deviation principles for the current and the tagged particle in the WASEP

We study the weakly asymmetric simple exclusion process in one dimension. We prove sample path moderate deviation principles for the current and the tagged particle when the process starts from one of its stationary measures. We simplify the proof in our previous works [Xue and Zhao, Electronic Journal of Probability, 2024] and [Xue and Zhao, Stochastic Processes and their Applications, 2023], where the same problem was investigated in the symmetric simple exclusion process.

math.PR↗
arXiv2025

Central limit theorems and moderate deviations for additive functionals of SSEP on regular trees

In this paper, we are concerned with the symmetric simple exclusion process (SSEP) on the regular tree $\mathcal{T}_d$. A central limit theorem and a moderate deviation principle of the additive functional of the process are proved, which include the CLT and the MDP of the occupation time as special cases. A graphical representation of the SSEP plays the key role in proofs of the main results, by which we can extend the martingale decomposition formula introduced in Kipnis (1987) for the occupation time to the case of general additive functionals.

math.PR↗
arXiv2025

Stationary fluctuation for the occupation time of the multi-species stirring process

In this paper, we prove a fluctuation theorem for the occupation time of the multi-species stirring process on a lattice starting from a stationary distribution. Our result shows that the occupation times of different species interact with each other at the level of equilibrium fluctuation. The proof of our result utilizes the resolvent strategy introduced in \cite{Kipnis1987}. A coupling relationship between the multi-species stirring process and an auxiliary process and a graphical representation of the auxiliary process play the key roles in the proof.

math.PR↗
arXiv2024

Sample path central limit theorem for the occupation time of the voter model on a lattice

In this paper, we extend the central limit theorem of the occupation time of the voter model on the lattice $\mathbb{Z}^d$ given in \cite{Cox1983} to the sample path case for $d\geq 3$. The proof of our main result utilizes the resolvent strategy and the Poisson flow strategy introduced in previous literatures, where the duality relationship between the voter model and the coalescing random walk plays the key role. For $d=2$ case, we give a conjecture about an analogue result of our main theorem.

math.PR↗
arXiv2024

Equilibrium moderate deviations for occupation times of SSEP on regula trees

In this paper, we are concerned with the symmetric simple exclusion process on the regula tree $\mathbb{T}^d$ for $d\geq 2$. Our main result gives moderate deviation principles of occupation times of the process starting from an invariant product measure. Two replacement lemmas play key roles in the proof of our main result. To obtain these replacement lemmas, we utilize duality relationships between the symmetric exclusion process and two types of random walks on $\mathbb{T}^d$ and $\left(\mathbb{T}^d\right)^2$ respectively.

math.PR↗
arXiv2024

Mean field limits of a class of conservative systems with position-dependent transition rates

In this paper, we are concerned with a class of conservative systems including asymmetric exclusion processes and zero-range processes as examples, where some particles are initially placed on $N$ positions. A particle jumps from a position to another at a rate depending on coordinates of these two positions and numbers of particles on these two positions. We show that the hydrodynamic limit of our model is driven by a nonlinear function-valued ordinary differential equation which is consistent with a mean field analysis. Furthermore, in the case where numbers of particles on all positions are bounded by $\mathcal{K}<+\infty$, we show that the fluctuation of our model is driven by a generalized Ornstein-Uhlenbeck process. A crucial step in proofs of our main results is to show that numbers of particles on different positions are approximately independent by utilizing a graphical method.

math.PR↗
arXiv2023

DAG-ACFL: Asynchronous Clustered Federated Learning based on DAG-DLT

Federated learning (FL) aims to collaboratively train a global model while ensuring client data privacy. However, FL faces challenges from the non-IID data distribution among clients. Clustered FL (CFL) has emerged as a promising solution, but most existing CFL frameworks adopt synchronous frameworks lacking asynchrony. An asynchronous CFL framework called SDAGFL based on directed acyclic graph distributed ledger techniques (DAG-DLT) was proposed, but its complete decentralization leads to high communication and storage costs. We propose DAG-ACFL, an asynchronous clustered FL framework based on directed acyclic graph distributed ledger techniques (DAG-DLT). We first detail the components of DAG-ACFL. A tip selection algorithm based on the cosine similarity of model parameters is then designed to aggregate models from clients with similar distributions. An adaptive tip selection algorithm leveraging change-point detection dynamically determines the number of selected tips. We evaluate the clustering and training performance of DAG-ACFL on multiple datasets and analyze its communication and storage costs. Experiments show the superiority of DAG-ACFL in asynchronous clustered FL. By combining DAG-DLT with clustered FL, DAG-ACFL realizes robust, decentralized and private model training with efficient performance.

cs.LG↗
arXiv2023

Nonequilibrium moderate deviations from hydrodynamics of simple exclusion processes

In this paper, we give the moderate deviation principle from the hydrodynamic limit of the simple exclusion process on $1$-dimensional torus starting from a nonequilibrium state, which extends the result given in Gao and Quastel (2003) about the case where the process starts from an equilibrium state. The exponential tightness of the scaled density field of the process and a replacement lemma play key roles in the proof of the main result. We utilize Grownwall's inequality and the upper bound of the large deviation principle given in Kipnis, Olla and Varadhan (1989) to prove above exponential tightness and replacement lemma respectively in the absence of the invariance of the initial distribution.

math.PR↗
arXiv2023

Large and moderate deviations for empirical density fields of stochastic SEIR epidemics with vertex-dependent transition rates

In this paper, we are concerned with stochastic susceptible-exposed-infected-removed epidemics on complete graphs with vertex-dependent transition rates. Large and moderate deviations of empirical density fields of our models are given. Proofs of our main results utilize exponential martingale strategies. Mathematical difficulties are mainly in checks of exponential tightness of fluctuation density fields of our processes. As an application of our main results, moderate deviations of a family of hitting times of our processes are also given.

math.PR↗
arXiv2023

The voter model with a slow membrane

We introduce the voter model on the infinite lattice with a slow membrane and investigate its hydrodynamic behavior and nonequilibrium fluctuations. The model is defined as follows: a voter adopts one of its neighbors' opinion at rate one except for neighbors crossing the hyperplane $\{x:x_1 = 1/2\}$, where the rate is $αN^{-β}$. Above, $α>0,\,β\geq 0$ are two parameters and $N$ is the scaling parameter. The hydrodynamic equation turns out to be heat equation with various boundary conditions depending on the value of $β$. For the nonequilibrium fluctuations, the limit is described by generalized Ornstein-Uhlenbeck process with certain boundary condition corresponding to the hydrodynamic equation.

math.PR↗
arXiv2022

An Energy Optimized Specializing DAG Federated Learning based on Event Triggered Communication

Specializing Directed Acyclic Graph Federated Learning(SDAGFL) is a new federated learning framework which updates model from the devices with similar data distribution through Directed Acyclic Graph Distributed Ledger Technology (DAG-DLT). SDAGFL has the advantage of personalization, resisting single point of failure and poisoning attack in fully decentralized federated learning. Because of these advantages, the SDAGFL is suitable for the federated learning in IoT scenario where the device is usually battery-powered. To promote the application of SDAGFL in IoT, we propose an energy optimized SDAGFL based event-triggered communication mechanism, called ESDAGFL. In ESDAGFL, the new model is broadcasted only when it is significantly changed. We evaluate the ESDAGFL on a clustered synthetically FEMNIST dataset and a dataset from texts by Shakespeare and Goethe's works. The experiment results show that our approach can reduce energy consumption by 33\% compared with SDAGFL, and realize the same balance between training accuracy and specialization as SDAGFL.

cs.LG↗
arXiv2022

Central limit theorems of occupation times of high-dimensional normalized binary contact path processes

The binary contact path process (BCPP) introduced in Griffeath (1983) describes the spread of an epidemic on a graph and is an auxiliary model in the study of improving upper bounds of the critical value of the contact process. In this paper, we are concerned with the central limit theorem of the occupation time of a normalized version of the BCPP (NBCPP) on a lattice. We show that the centred occupation time process of the NBCPP converges in finite dimensional distributions to a Brownian motion when the dimension of the lattice and the infection rate of the model are sufficiently large and the initial state of the NBCPP is distributed with a particular invariant distribution.

math.PR↗
arXiv2022

Scaling limits and fluctuations of a family of $N$-urn branching processes

In this paper we are concerned with a family of $N$-urn branching processes, where some particles are put into $N$ urns initially and then each particle gives birth to several new particles in some urn when dies. This model includes the $N$-urn Ehrenfest model and the $N$-urn branching random walk as special cases. We show that the scaling limit of the process is driven by a $C(\mathbb{T})$-valued linear ordinary differential equation and the fluctuation of the process is driven by a generalized Ornstein-Uhlenbeck process in the dual of $C^\infty(\mathbb{T})$, where $\mathbb{T}=(0, 1]$ is the one-dimensional torus. A crucial step for proofs of above main results is to show that numbers of particles in different urns are approximately independent. As applications of our main results, limit theorems of hitting times of the process are also discussed.

math.PR↗