arXiv subjects

Yulong Ma

Publications and source records attributed to Yulong Ma.

4 recordsLinked to original sources

arXiv2023

A Real-time Non-contact Localization Method for Faulty Electric Energy Storage Components using Highly Sensitive Magnetometers

With the wide application of electric energy storage component arrays, such as battery arrays, capacitor arrays, inductor arrays, their potential safety risks have gradually drawn the public attention. However, existing technologies cannot meet the needs of non-contact and real-time diagnosis for faulty components inside these massive arrays. To solve this problem, this paper proposes a new method based on the beamforming spatial filtering algorithm to precisely locate the faulty components within the arrays in real-time. The method uses highly sensitive magnetometers to collect the magnetic signals from energy storage component arrays, without damaging or even contacting any component. The experimental results demonstrate the potential of the proposed method in securing energy storage component arrays. Within an imaging area of 80 mm $\times$ 80 mm, the one faulty component out of nine total components can be localized with an accuracy of 0.72 mm for capacitor arrays and 1.60 mm for battery arrays.

physics.app-ph↗

arXiv2023

Distributed Traffic Engineering in Hybrid Software Defined Networks: A Multi-agent Reinforcement Learning Framework

Traffic Engineering (TE) is an efficient technique to balance network flows and thus improves the performance of a hybrid Software Defined Network (SDN). Previous TE solutions mainly leverage heuristic algorithms to centrally optimize link weight setting or traffic splitting ratios under the static traffic demand. Note that as the network scale becomes larger and network management gains more complexity, it is notably that the centralized TE methods suffer from a high computation overhead and a long reaction time to optimize routing of flows when the network traffic demand dynamically fluctuates or network failures happen. To enable adaptive and efficient routing in TE, we propose a Multi-agent Reinforcement Learning method CMRL that divides the routing optimization of a large network into multiple small-scale routing decisionmaking problems. To coordinate the multiple agents for achieving a global optimization goal, we construct an interactive environment for training the routing agents that own partial link utilization observations. To optimize credit assignment of multi-agent, we introduce the difference reward assignment mechanism for encouraging agents to take better action. Extensive simulations conducted on the real traffic traces demonstrate the superiority of CMRL in improving TE performance, especially when traffic demands change or network failures happen.

cs.NI↗

arXiv2020

Statistical screening model for moderately coupled and dense plasmas

For atoms embedded in dense plasma, the plasma screening effects will greatly alter their structure and dynamics, and then determine the radiation transport properties of the plasma. In the present work, a new statistical model is proposed for treating electron screening effects on atoms in moderately/strongly coupled and dense plasmas, in which the three-body processes are found to significantly influence the plasma-electron density distributions and leads to a dependence of the distribution on the specific bound state of the targeted atom. As a critical check, the model is applied to simulate the emission spectra of He-like Aluminum and Chlorine in hot dense plasmas, and much better agreements of the line shifts are obtained with the experiments of Stillman et al. in 2017 and Beiersdorfer et al. in 2019 than previous calculation results. Compared with the classical molecular dynamic simulations of electron distributions in moderately coupled plasmas, the present model can better describe the low-energy electron distribution than other models and the multi-body effects are well considered. The present model provides a promising tool to reasonably treat the electron screening effect of non-equilibrium dense plasma on atoms with specific bound states, which is urgently needed in high-precision simulations of the atomic processes, plasma spectra and radiation transport properties etc.

physics.plasm-ph↗

arXiv2019

Strong Modification of Radiative Transition Rates due to a Breit-Interaction-Induced Avoided Crossing

We present the observations of x-rays emitted from the $1s2s^{2}2p_{1/2}2p_{3/2}$ inner shell excited state of B-like W and Bi ions. The relative transition rates are obtained for two dominant radiative transitions to $1s^{2}2s^{2}2p_{1/2}$ and $1s^{2}2s^{2}2p_{3/2}$. The experimental results and the comparison with rigorous relativistic calculations show that the rates of the strong electric dipole allowed $1s^22s^22p$ -- $1s2s^22p^2$ transitions are strongly modified due to a drastic change in the wavefunction caused by the Breit interaction.

physics.atom-ph↗