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Baiyu Liu

Publications and source records attributed to Baiyu Liu.

11 recordsLinked to original sources
arXiv2025

A muon scattering tomography system based on high spatial resolution scintillating detector

Cosmic ray muon scattering tomography (MST) is an imaging technique that utilizes muon scattering in matter to inspect high-Z materials non-destructively, without requiring an artificial radiation source. This method offers significant potential for applications in border security and long-term monitoring of nuclear materials. In this study, we developed a high-precision plastic-scintillator-based position-sensitive detector with a spatial resolution of 0.09 times the strip pitch. A fully functional, full-scale imaging system was then constructed using four layers of such XY position-sensitive detectors, each with an effective area of 53 cm x 53 cm. This paper details the following key contributions: the Geant4-simulated design and optimization of the imaging system, the fabrication, assembly, and testing of the detectors, and an evaluation of the imaging performance of the completed system.

physics.ins-det↗
arXiv2024

Asymptotic symmetry of solutions for reaction-diffusion equations via elliptic geometry

In this paper, we investigate the asymptotic symmetry and monotonicity of positive solutions to a reaction-diffusion equation in the unit ball, utilizing techniques from elliptic geometry. Firstly, we discuss the properties of solutions in the elliptic space. Then, we establish crucial principles, including the asymptotic narrow region principle.Finally, we employ the method of moving planes to demonstrate the asymptotic symmetry of the solutions.

math.AP↗
arXiv2023

Monotonicity of positive solutions for an indefinite logarithmic Laplacian equation

In this paper, we investigate a nonlocal equation involving the logarithmic Laplacian with indefinite nonlinearities: \begin{equation*} \left\{ \begin{array}{ll} L_Δu(x)=a(x_n)f(u), & x\inΩ, \\ u(x)=0,& x\in \mathbb{R}^n\backslashΩ. \end{array} \right. \end{equation*} Here, $Ω$ represents a Lipschitz coercive epigraph. To achieve our objectives, we develop a boundary estimate for antisymmetric functions, enabling us to establish the monotonicity and nonexistence of bounded positive solutions for the above problem using the direct method of moving planes.

math.AP↗
arXiv2018

Finite time blow-up and global solutions for a nonlocal parabolic equation at high energy level

In this paper, we consider the solution of a nonlocal parabolic equation. Focusing on the solutions with initial data at high energy level, we find the criteria for global existence and finite time blow up for the corresponding solution respectively. Moreover, we prove that there always exists blow up solution with negative Nehari functional no matter how large the energy is.

math.AP↗
arXiv2018

A Scalable Permission Management System With Support of Conditional and Customized Attributes

Along with the classical problem of managing multiple identities, actions, devices, APIs etc. in different businesses, there has been an escalating need for having the capability of flexible attribute based access control~(ABAC) mechanisms. In order to fill this gap, several variations of ABAC model have been proposed such as \textit{Amazon's AWS IAM}, which uses JSON as their underlying storage data structure and adds policies/constraints as fields over the regular ABAC. However, these systems still do not provide the capability to have customized permissions and to perform various operations (such as comparison/aggregation) on them. In this paper, we introduce a string based resource naming strategy that supports the customized and conditional permissions for resource access. Further, we propose the basic architecture of our system which, along with our naming scheme, makes the system scalable, secure, efficient, flexible and customizable. Finally, we present the proof of concept for our algorithm as well as the experimental set up and the future trajectory for this work.

cs.CR↗
arXiv2017

Vacuum isolating, blow up threshold and asymptotic behavior of solutions for a nonlocal parabolic equation

In this paper, we consider a nonlocal parabolic equation associated with initial and Dirichlet boundary conditions. Firstly, we discuss the vacuum isolating behavior of solutions with the help of a family of potential wells. Then we obtain a threshold of global existence and blow up for solutions with critical initial energy. Furthermore, for those solutions satisfy $J(u_0)\leq d$ and $I(u_0)\neq 0$, we show that global solutions decay to zero exponentially as time tends to infinity and the norm of blow-up solutions increase exponentially.

math.AP↗
arXiv2016

Radial symmetry results for fractional Laplacian systems

In this paper, we generalize the direct method of moving planes for the fractional Laplacian to the system case. Considering a coupled nonlinear system with fractional Laplacian, we first establish a decay at infinity principle and a narrow region principle. Using these principles, we obtain two radial symmetry results for the decaying solutions of the fractional Laplacian systems. Our method can be applied to fractional Schrödinger systems and fractional Hénon systems.

math.AP↗
arXiv2007

L2 p-Forms and Ricci flow with bounded curvature on manifolds

In this paper, we study the evolution of L2 p-forms under Ricci flow with bounded curvature on a complete non-compact or a compact Riemannian manifold. We show that under curvature pinching conditions on such a manifold, the L2 norm of a smooth p-form is non-increasing along the Ricci flow. The L^{\infty} norm is showed to have monotonicity property too.

math.DG↗