检索结果-南通市图书馆

Euler-type schemes for weakly coupled forward-backward stochastic differential equations and optimal convergence analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2015年第2期10卷 415-434页

作者： Wei ZHANG weidong zhao School of Mathematics Finance Institute Shandong University Jinan 250100 China

We introduce a new Euler-type scheme and its iterative algorithm for solving weakly coupled forward-backward stochastic differential equations （FBSDEs）. Although the schemes share some common features with the ones proposed by C. Bender and J. Zhang [Ann. Appl. Probab., 2008, 18： 143-177], less computational work is needed for our method. For both our schemes and the ones proposed by Bender and Zhang, we rigorously obtain first-order error estimates, which improve the half-order error estimates of Bender and Zhang. Moreover, numerical tests are given to demonstrate the first-order accuracy of the schemes.

关键词： Weakly coupled forward-backward stochastic differential equations (FBSDEs) Euler-type scheme time discretization first-order error estimate

ODE-Based Multistep Schemes for Backward Stochastic Differential Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2023年第4期16卷 1053-1086页

作者： Shuixin Fang weidong zhao School of Mathematics&Institute of Finance Shandong UniversityJinanShandong 250100P.R.China

In this paper,we explore a new approach to design and analyze numerical schemes for backward stochastic differential equations(BSDEs).By the nonlinear Feynman-Kac formula,we reformulate the BSDE into a pair of reference ordinary differential equations(ODEs),which can be directly discretized by many standard ODE solvers,yielding the corresponding numerical schemes for *** particular,by applying strong stability preserving(SSP)time discretizations to the reference ODEs,we can propose new SSP multistep schemes for *** analyses are rigorously performed to prove the consistency,stability and convergency of the proposed SSP multistep *** experiments are further carried out to verify our theoretical results and the capacity of the proposed SSP multistep schemes for solving complex associated problems.

关键词： Backward stochastic differential equation parabolic partial differential equation strong stability preserving linear multistep scheme high order discretization

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于RCF的细化边缘检测模型

Journal of Measurement Science and Instrumentation 2024年第2期15卷 195-203页

作者：赵卫东张瑶张丹丹凌强安徽工业大学电气与信息工程学院安徽马鞍山243000

边缘检测是图像处理和计算机视觉中的基本问题。针对基于深度学习的边缘检测技术(如RCF网络)存在生成的边缘线模糊粗糙及边缘信息不全等问题,本文提出一种基于RCF网络的细化边缘检测模型RED。该模型在RCF模型的基础上,去除主干网络中部... 详细信息

边缘检测是图像处理和计算机视觉中的基本问题。针对基于深度学习的边缘检测技术(如RCF网络)存在生成的边缘线模糊粗糙及边缘信息不全等问题,本文提出一种基于RCF网络的细化边缘检测模型RED。该模型在RCF模型的基础上,去除主干网络中部分下采样,并在主干网络中引入CA注意力模块和混合扩张卷积;在深监督模块改变压缩层的数量和参数,采用平滑压缩的方式进行特征降维;在最后的融合模块,采用跨层交叉融合的方式来融合高低层间的信息。改进后的模型在扩充后的BSDS500数据集上进行了训练和测试,通过在BSDS500基准上进行评估得到数据集最优尺度(ODS)和单图最优尺度(OIS),分别为0.809和0.832。实验结果表明,该模型提取的边缘轮廓更加清晰细致,提取到的边缘信息也更加全面丰富。

关键词：深度学习边缘检测扩张卷积坐标注意力跨层融合

多周期常减压蒸馏装置换热网络用能变化与柔性优化

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

石油炼制与化工 2024年第6期55卷 130-136页

作者：刘泽坤刘绍东赵卫东王彧斐中国石油大学(北京) 北京102249 中国石油塔里木油田分公司

常减压蒸馏装置能耗在整个炼油厂中最高,优化其换热网络是节能的有效手段。考虑到所加工油品会发生变化,以往针对特定原油设计的换热网络在处理其他原油时表现不再最优。提出一种多周期柔性优化方法:首先对不同原油周期进行流程模拟,随... 详细信息

常减压蒸馏装置能耗在整个炼油厂中最高,优化其换热网络是节能的有效手段。考虑到所加工油品会发生变化,以往针对特定原油设计的换热网络在处理其他原油时表现不再最优。提出一种多周期柔性优化方法:首先对不同原油周期进行流程模拟,随后模拟现行换热网络,辨识夹点位置偏移,发现不合理用能发生位置,通过改变管路结构并调节换热匹配,提高换热网络柔性,消除部分共有的跨夹点传热。在某炼油厂的应用结果表明,多周期柔性设计可在周期1、周期2、周期3、周期4分别节约1421,880,3842,3421 kW的加热炉热负荷和等量的冷却负荷。对多周期换热网络用能变化规律的深入研究和柔性设计,可为炼油厂节能降耗做出更大贡献。

关键词：常减压蒸馏流程模拟换热网络夹点技术多周期柔性优化

Revisiting GM-CSF as an adjuvant for therapeutic vaccines

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2018年第2期15卷 187-189页

作者： weidong zhao Gan zhao Bin Wang Key Laboratory of Medical Molecular Virology of the Ministry of Health and Ministry of Education School of Basic Medical SciencesFudan UniversityShanghai200032China Department of Laboratory Medicine Clinical Medicine CollegeDali UniversityDali 200032China. PhD Key Laboratory of Medical Molecular Virology of the Ministry of Health and Ministry of EducationSchool of Basic Medical SciencesFudan University131 Dong An RoadShanghai200032China

Granulocyte macrophage colony stimulating factor(GM-CSF)is generally considered to be a proinflammatory cytokine;GM-CSF-based vaccines have been shown to elicit potent antitumor and antiviral immune responses in preclinical *** clinical trials,however,these effects were not as robust and sometimes even contradicted the findings from animal *** this commentary,we aim to discuss the latest advances in this field,hoping that an upto-date and comprehensive understanding of this molecule will help others design effective GM-CSF-based strategies for antiviral and anticancer vaccines.

关键词： vaccines clinical stimulating

Finite Element Methods for Nonlinear Backward Stochastic Partial Differential Equations and Their Error Estimates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2020年第6期12卷 1457-1480页

作者： Xu Yang weidong zhao School of Mathematics China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mathematics Shandong UniversityJinanShandong 250100China

In this paper,we consider numerical approximation of a class of nonlinear backward stochastic partial differential equations(BSPDEs).By using finite element methods in the physical space domain and the Euler method in the time domain,we propose a spatial finite element semi-discrete scheme and a spatio-temporal full discrete scheme for solving the *** of the schemes are rigorously analyzed and theoretical error estimates with convergence rates are obtained.

关键词： Backward stochastic partial differential equations finite element method error estimate.

Sinc-Multistep Schemes for Forward Backward Stochastic Differential Equations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2023年第3期15卷 737-768页

作者： Xu Wang weidong zhao School of Mathematics&Institute of Finance Shandong UniversityJinanShandong 250100China

In this work,by combining the multistep discretization in time and the Sinc quadrature rule for approximating the conditional mathematical expectations,we will propose new fully discrete multistep schemes called“Sinc-multistep schemes”for forward backward stochastic differential equations(FBSDEs).The schemes avoid spatial interpolations and admit high order of *** stability and the K-th order error estimates in time for the K-step Sinc multistep schemes are theoretically proved(1≤K≤6).This seems to be the first time for analyzing fully time-space discrete multistep schemes for *** examples are also presented to demonstrate the effectiveness,stability,and high order of convergence of the proposed schemes.

关键词： Forward backward stochastic differential equations multistep schemes Sinc quadrature rule error estimates

当代语境下中华传统文化符号在文创产品中的多维转译探析

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

包装工程 2024年第4期45卷 362-370,457页

作者：赵卫东胡伟专张玉典陈倍贝四川美术学院重庆401331 江南大学江苏无锡214122 浙江理工大学杭州310018

目的探析当代语境下中华传统文化符号在文创产品中转译的挑战与对策,促进中华传统文化符号更好地融入当代社会审美体系,进而推动中华传统文化的传承、创新与发展。方法从社会、技术与文化三个方面分析中华传统文化符号所处的时代语境特... 详细信息

目的探析当代语境下中华传统文化符号在文创产品中转译的挑战与对策,促进中华传统文化符号更好地融入当代社会审美体系,进而推动中华传统文化的传承、创新与发展。方法从社会、技术与文化三个方面分析中华传统文化符号所处的时代语境特征、机遇与挑战,再以此为基础,探讨中华传统文化符号在文创产品中转译的当代创新策略,并通过典型案例分析进行佐证说明。结论提出中华传统文化符号在文创产品中转译的当代创新策略,以寓意多级转化新创中华传统文化符号的内涵意义,以数智技术融入提升中华文化传统文化符号的表现魅力,以多维叙事共情拓展中华传统文化符号的体验深度。

关键词：中华传统文化符号文创产品符号转译产品设计

A FIRST-ORDER NUMERICAL SCHEME FOR FORWARD-BACKWARD STOCHASTIC DIFFERENTIAL EQUATIONS IN BOUNDED DOMAINS

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2018年第2期36卷 237-258页

作者： Jie Yang Guannan Zhang weidong zhao School of Mathematics and Statistics Shandong University Weihai Shandong 264209 China Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 United States School of Mathematics Shandong University Jinan Shandong 250100 China

We propose a novel numerical scheme for decoupled forward-backward stochastic differ- ential equations （FBSDEs） in bounded domains, which corresponds to a class of nonlinear parabolic partial differential equations with Dirichlet boundary conditions. The key idea is to exploit the regularity of the solution （Yt,Zt） with respect to Xt to avoid direct ap- proximation of the involved random exit time. Especially, in the one-dimensional case, we prove that the probability of Xt exiting the domain within At is on the order of O（（△t）ε exp（--1/（△t）2ε））, if the distance between the start point X0 and the boundary is 1 g at least on the order of O（△t）^1/2-ε ） for any fixed c 〉 0. Hence, in spatial discretization, we set the mesh size △x - （9（（At）^1/2-ε ）, so that all the interior grid points are sufficiently far from the boundary, which makes the error caused by the exit time decay sub-exponentially with respect to △t. The accuracy of the approximate solution near the boundary can be guaranteed by means of high-order piecewise polynomial interpolation. Our method is developed using the implicit Euler scheme and cubic polynomial interpolation, which leads to an overall first-order convergence rate with respect to △t.

关键词： Forward-backward stochastic differential equations Exit time Dirichlet bound-ary conditions Implicit Euler scheme.