網(wǎng)絡(luò)空間安全學(xué)院學(xué)術(shù)講座(四、五、六、七)
題目一：A novel L1 scheme for reaction-subdiffusion equations
內(nèi)容簡(jiǎn)介：This talk is concerned with numerical solutions of reaction-subdiffusion equations. Due to the Caputo time derivative being involved, the solutions of equations are usually singular near the initial time $t=0$ even for a smooth setting. Based on a simple change of variable $s=t^\beta$, an equivalent $s$-fractional differential equation is derived and analyzed. Two type finite difference methods based on linear and quadratic approximations in the $s$-direction are presented, respectively. Our numerical results show clearly the accuracy and efficiency of the proposed methods.
報(bào)告人：華中科技大學(xué)李東方教授
報(bào)告人簡(jiǎn)介：華中科技大學(xué)數(shù)學(xué)與統(tǒng)計(jì)學(xué)院教授，博導(dǎo)，中國(guó)系統(tǒng)仿真學(xué)會(huì)仿真算法專(zhuān)業(yè)委員會(huì)委員。曾先后赴加拿大McGill大學(xué)，香港城市大學(xué)從事博士后研究。主要研究微分方程數(shù)值解、系統(tǒng)仿真和信號(hào)處理等領(lǐng)域，在微分方程保結(jié)構(gòu)算法和分?jǐn)?shù)階微分方程的高效數(shù)值算法和理論上取得一些有意義的進(jìn)展。主要工作發(fā)表在《SIAM. J. Numer. Anal.》，《SIAM. J. Sci. Comput.》、《J. Comp. Phys.》、《Appl. Comp. Harm. Appl.》、《J. Sci. Comput》等多個(gè)國(guó)際著名計(jì)算學(xué)科SCI期刊上，多篇為高被引論文。
題目二：后摩爾時(shí)代高性能并行應(yīng)用挑戰(zhàn)
內(nèi)容簡(jiǎn)介：信息科技發(fā)展依賴(lài)于芯片制程的發(fā)展，隨著摩爾定律的終結(jié)，整個(gè)信息產(chǎn)業(yè)及人類(lèi)科技都將面臨巨大挑戰(zhàn)。介紹了美國(guó)NSCI計(jì)劃、常用的核心算法和高性能并行應(yīng)用處理挑戰(zhàn)的方向。
報(bào)告人：國(guó)防科技大學(xué)龔春葉副研究員
報(bào)告人簡(jiǎn)介：國(guó)防科大計(jì)算機(jī)學(xué)院副研究員，計(jì)算機(jī)所應(yīng)用室主任，主任設(shè)計(jì)師，天河團(tuán)隊(duì)高性能并行應(yīng)用方向帶頭人。應(yīng)用數(shù)學(xué)學(xué)士、計(jì)算機(jī)科學(xué)與技術(shù)博士、航空宇航科學(xué)與技術(shù)博士后。帶領(lǐng)團(tuán)隊(duì)完成天河二號(hào)、天河三號(hào)原型機(jī)等重大工程項(xiàng)目并行應(yīng)用研發(fā)工作，在面向核數(shù)值模擬、航空航天CFD計(jì)算、密碼破解待國(guó)家重大領(lǐng)域的并行算法、國(guó)產(chǎn)網(wǎng)格生成軟件等領(lǐng)域有深入研究。負(fù)責(zé)科技部重點(diǎn)研發(fā)計(jì)劃、國(guó)家數(shù)值風(fēng)洞、自然科學(xué)基金等項(xiàng)目多項(xiàng)，團(tuán)隊(duì)經(jīng)費(fèi)超4000萬(wàn)。發(fā)表論文20余篇，專(zhuān)利10余項(xiàng)。
題目三：Some techniques for accelerating parallel direct method for symmetric eigenvalue problems
內(nèi)容簡(jiǎn)介：In this talk, we will introduce some techniques for accelerating parallel direct methods for symmetric eigenvalue problems, which can be divided into two different approaches. One is based on the techniques of rank-structure matrices, and it can make the tridiagonal DC algorithm in Scalapack 40-60% times faster. Another is a hybrid algorithm and combines the techniques of direct methods with iterative methods, and finally can be used to compute partial or full eigendecomposition of symmetric dense matrices. This hybrid algorithm is named PDESHEP, and the iterative method in PDESHEP is based on the contour integral method implemented in FEAST. Numerical results show that PDESHEP can be 25% times faster than the state-of-the-art direct solver in ELPA when using 4096 processes on Tianhe-2 supercomputer.
報(bào)告人：國(guó)防科技大學(xué)李勝?lài)?guó)助理研究員
報(bào)告人簡(jiǎn)介：計(jì)算數(shù)學(xué)博士，國(guó)防科技大學(xué)計(jì)算機(jī)學(xué)院助理研究員，2006-2013年獲得國(guó)防科技大學(xué)的應(yīng)用數(shù)學(xué)學(xué)士、計(jì)算數(shù)學(xué)碩士和博士學(xué)位，2010年在美國(guó)加州大學(xué)伯克利分校聯(lián)合培養(yǎng)兩年，2020年訪(fǎng)問(wèn)西班牙UPV大學(xué)10個(gè)月。2013年參加工作以來(lái)，主要從事并行算法設(shè)計(jì)、特征值計(jì)算、共性算法庫(kù)研制、Benchmark程序測(cè)試與優(yōu)化工作，參與天河2A、銀河-X研制與系統(tǒng)調(diào)試工作，曾主持國(guó)家青年和湖南省面上自然科學(xué)基金1項(xiàng)，發(fā)表SCI論文20多篇，兩篇進(jìn)入ESI檢索前10%，部分論文發(fā)表在SIAM J. Sci. Comput., SIAM J. Matrix Anal. Appl., Numer. Math., Numer. Linear Algebra Appl. Parallel Computing, IEEE TPDS等國(guó)際期刊。
題目四：Dynamics of the generalized Kuramoto model with nonlinear coupling: Bifurcation and stability
內(nèi)容簡(jiǎn)介：We systematically study dynamics of a generalized Kuramoto model of globally coupled phase oscillators. The coupling of modified model depends on the fraction of phase-locked oscillators via a power-law function of the Kuramoto order parameter r through an exponent α, such that α = 1 corresponds to the standard Kuramoto model, α < 1 strengthens the global coupling, and the global coupling is weakened if α > 1. With a self-consistency approach, we demonstrate that bifurcation diagrams of synchronization for different values of α are thoroughly constructed from two parametric equations. In contrast to the case of α = 1 with a typical second-order phase transition to synchronization, no phase transition to synchronization is predicted for α < 1, as the onset of partial locking takes place once the coupling strength K > 0. For α > 1, we establish an abrupt desynchronization transition from the partially (fully) locked state to the incoherent state, whereas there is no counterpart of abrupt synchronization transition from incoherence to coherence due to that the incoherent state remains linearly neutrally stable for all K > 0. For each case of α, by performing a standard linear stability analysis for the reduced system with Ott-Antonsen ansatz, we analytically derive the continuous and discrete spectra of both the incoherent state and the partially (fully) locked states. All our theoretical results are obtained in the thermodynamic limit, which have been well validated by extensive numerical simulations of the phase-model with a sufficiently large number of oscillators.
報(bào)告人：華南師范大學(xué)鄒為副教授
報(bào)告人簡(jiǎn)介：華南師范大學(xué)數(shù)學(xué)科學(xué)學(xué)院副教授，廣東省青年珠江學(xué)者，2010年獲得中科院武漢物理與數(shù)學(xué)研究所應(yīng)用數(shù)學(xué)博士學(xué)位，博士論文獲2011年度中國(guó)科學(xué)院百篇優(yōu)秀博士論文獎(jiǎng)，2011年至2013年獲得德國(guó)洪堡獎(jiǎng)學(xué)金資助在德國(guó)柏林洪堡大學(xué)從事博士后研究工作，2016年至2018年在香港浸會(huì)大學(xué)從事香江學(xué)者博士后研究工作，長(zhǎng)期從事復(fù)雜系統(tǒng)、非線(xiàn)性科學(xué)理論研究，在耦合非線(xiàn)性系統(tǒng)的群體動(dòng)力學(xué)行為研究問(wèn)題上取得系統(tǒng)成果。目前已在非線(xiàn)性動(dòng)力學(xué)主流期刊發(fā)表SCI論文40余篇， H指數(shù)16，SCI總引用1000余次。 以第一作者發(fā)表了20多篇SCI學(xué)術(shù)論文，包括1篇Nature Communications及1篇Physical Review Letters等。目前主持1項(xiàng)國(guó)家自然科學(xué)基金面上項(xiàng)目，主持并完成國(guó)家自然科學(xué)基金2項(xiàng)。
時(shí)間：2021年3月20日（周六）下午14：30～18：00
地點(diǎn)：騰訊會(huì)議 ID：509 142 563會(huì)議密碼：200320
熱烈歡迎廣大師生參加!
2021年3月19日