作为一种分布式训练框架,联邦学习在无线通信领域有着广阔的应用前景,也面临着多方面的技术挑战,其中之一源于参与训练用户数据集的非独立同分布(Independent and identically distributed,IID)。不少文献提出了解决方法,以减轻户数据集...作为一种分布式训练框架,联邦学习在无线通信领域有着广阔的应用前景,也面临着多方面的技术挑战,其中之一源于参与训练用户数据集的非独立同分布(Independent and identically distributed,IID)。不少文献提出了解决方法,以减轻户数据集非IID造成的联邦学习性能损失。本文以平均信道增益预测、正交幅度调制信号的解调这两个无线任务以及两个图像分类任务为例,分析用户数据集非IID对联邦学习性能的影响,通过神经网络损失函数的可视化和对模型参数的偏移量进行分析,尝试解释非IID数据集对不同任务影响程度不同的原因。分析结果表明,用户数据集非IID未必导致联邦学习性能的下降。在不同数据集上通过联邦平均算法训练得到的模型参数偏移程度和损失函数形状有很大的差异,二者共同导致了不同任务受数据非IID影响程度的不同;在同一个回归问题中,数据集非IID是否影响联邦学习的性能与引起数据非IID的具体因素有关。展开更多
车联网在智慧城市建设中扮演着不可或缺的角色,汽车不仅仅是交通工具,更是大数据时代信息采集和传输的重要载体.随着车辆采集的数据量飞速增长和人们隐私保护意识的增强,如何在车联网环境中确保用户数据安全,防止数据泄露,成为亟待解决...车联网在智慧城市建设中扮演着不可或缺的角色,汽车不仅仅是交通工具,更是大数据时代信息采集和传输的重要载体.随着车辆采集的数据量飞速增长和人们隐私保护意识的增强,如何在车联网环境中确保用户数据安全,防止数据泄露,成为亟待解决的难题.联邦学习采用“数据不动模型动”的方式,为保护用户隐私和实现良好性能提供了可行方案.然而,受限于采集设备、地域环境、个人习惯的差异,多台车辆采集的数据通常表现为非独立同分布(non-independent and identically distributed,non-IID)数据,而传统的联邦学习算法在non-IID数据环境中,其模型收敛速度较慢.针对这一挑战,提出了一种面向non-IID数据的车联网多阶段联邦学习机制,称为FedWO.第1阶段采用联邦平均算法,使得全局模型快速达到一个基本的模型准确度;第2阶段采用联邦加权多方计算,依据各车辆的数据特性计算其在全局模型中的权重,聚合后得到性能更优的全局模型,同时采用传输控制策略,减少模型传输带来的通信开销;第3阶段为个性化计算阶段,车辆利用各自的数据进行个性化学习,微调本地模型获得与本地数据更匹配的模型.实验采用了驾驶行为数据集进行实验评估,结果表明相较于传统方法,在non-IID数据场景下,FedWO机制保护了数据隐私,同时提高了算法的准确度.展开更多
个性化联邦学习侧重于为各客户端提供个性化模型,旨在提高对异构数据的处理性能,然而现有的个性化联邦学习算法大多以增加客户端参数量为代价提高个性化模型的性能,使计算变得复杂.为了解决此问题,文中提出基于稀疏正则双层优化的个性...个性化联邦学习侧重于为各客户端提供个性化模型,旨在提高对异构数据的处理性能,然而现有的个性化联邦学习算法大多以增加客户端参数量为代价提高个性化模型的性能,使计算变得复杂.为了解决此问题,文中提出基于稀疏正则双层优化的个性化联邦学习算法(Personalized Federated Learning Based on Sparsity Regularized Bi-level Optimization,pFedSRB),在客户端的个性化更新中引入l 1范数稀疏正则化,提升个性化模型的稀疏度,避免不必要的客户端参数更新,降低模型复杂度.将个性化联邦学习建模为双层优化问题,内层优化采用交替方向乘子法,可提高学习速度.在4个联邦学习基准数据集上的实验表明,pFedSRB在异构数据上表现出色,在提高模型性能的同时有效降低训练用时和空间成本.展开更多
With the notion of independent identically distributed(IID) random variables under sublinear expectations introduced by Peng,we investigate moment bounds for IID sequences under sublinear expectations. We obtain a mom...With the notion of independent identically distributed(IID) random variables under sublinear expectations introduced by Peng,we investigate moment bounds for IID sequences under sublinear expectations. We obtain a moment inequality for a sequence of IID random variables under sublinear expectations. As an application of this inequality,we get the following result:For any continuous functionsatisfying the growth condition |(x) | C(1 + |x|p) for some C > 0,p 1 depending on ,the central limit theorem under sublinear expectations obtained by Peng still holds.展开更多
With Globally Important Agricultural Heritage Systems(GIAHS)increasing in number around the world,their conservation has become a new international research theme.From the perspective of combining theoretical analyses...With Globally Important Agricultural Heritage Systems(GIAHS)increasing in number around the world,their conservation has become a new international research theme.From the perspective of combining theoretical analyses and practical case applications,this study examines the Important Agricultural Heritage Systems(IAHS)conservation pathways and operation mechanisms through industrial integration development(IID).First,the theoretical framework of IID in IAHS sites was constructed according to the requirements of IAHS conservation,which include analyses of the connotation and basic principles of IID,the necessity of IID for IAHS sites,the resource conditions,and the IID pathways.And then based on the theoretical framework,the IID of Longji Terraces in Guangxi,Honghe Hani Rice Terraces System in Yunnan(HHRTS),Aohan Dryland Farming System in Inner Mongolia(ADFS),and Huzhou Mulberry-dyke&Fish-pond System(HMFS)in Zhejiang are analyzed systematically.The main finding is that IID is an effective pathway for IAHS conservation.However,the IID in IAHS sites must stress the ecological and cultural values of the resources;IID should be based on local resource advantages;and IID should attach importance to the combination of different policies and coordination between different stakeholders.展开更多
文摘作为一种分布式训练框架,联邦学习在无线通信领域有着广阔的应用前景,也面临着多方面的技术挑战,其中之一源于参与训练用户数据集的非独立同分布(Independent and identically distributed,IID)。不少文献提出了解决方法,以减轻户数据集非IID造成的联邦学习性能损失。本文以平均信道增益预测、正交幅度调制信号的解调这两个无线任务以及两个图像分类任务为例,分析用户数据集非IID对联邦学习性能的影响,通过神经网络损失函数的可视化和对模型参数的偏移量进行分析,尝试解释非IID数据集对不同任务影响程度不同的原因。分析结果表明,用户数据集非IID未必导致联邦学习性能的下降。在不同数据集上通过联邦平均算法训练得到的模型参数偏移程度和损失函数形状有很大的差异,二者共同导致了不同任务受数据非IID影响程度的不同;在同一个回归问题中,数据集非IID是否影响联邦学习的性能与引起数据非IID的具体因素有关。
文摘车联网在智慧城市建设中扮演着不可或缺的角色,汽车不仅仅是交通工具,更是大数据时代信息采集和传输的重要载体.随着车辆采集的数据量飞速增长和人们隐私保护意识的增强,如何在车联网环境中确保用户数据安全,防止数据泄露,成为亟待解决的难题.联邦学习采用“数据不动模型动”的方式,为保护用户隐私和实现良好性能提供了可行方案.然而,受限于采集设备、地域环境、个人习惯的差异,多台车辆采集的数据通常表现为非独立同分布(non-independent and identically distributed,non-IID)数据,而传统的联邦学习算法在non-IID数据环境中,其模型收敛速度较慢.针对这一挑战,提出了一种面向non-IID数据的车联网多阶段联邦学习机制,称为FedWO.第1阶段采用联邦平均算法,使得全局模型快速达到一个基本的模型准确度;第2阶段采用联邦加权多方计算,依据各车辆的数据特性计算其在全局模型中的权重,聚合后得到性能更优的全局模型,同时采用传输控制策略,减少模型传输带来的通信开销;第3阶段为个性化计算阶段,车辆利用各自的数据进行个性化学习,微调本地模型获得与本地数据更匹配的模型.实验采用了驾驶行为数据集进行实验评估,结果表明相较于传统方法,在non-IID数据场景下,FedWO机制保护了数据隐私,同时提高了算法的准确度.
文摘个性化联邦学习侧重于为各客户端提供个性化模型,旨在提高对异构数据的处理性能,然而现有的个性化联邦学习算法大多以增加客户端参数量为代价提高个性化模型的性能,使计算变得复杂.为了解决此问题,文中提出基于稀疏正则双层优化的个性化联邦学习算法(Personalized Federated Learning Based on Sparsity Regularized Bi-level Optimization,pFedSRB),在客户端的个性化更新中引入l 1范数稀疏正则化,提升个性化模型的稀疏度,避免不必要的客户端参数更新,降低模型复杂度.将个性化联邦学习建模为双层优化问题,内层优化采用交替方向乘子法,可提高学习速度.在4个联邦学习基准数据集上的实验表明,pFedSRB在异构数据上表现出色,在提高模型性能的同时有效降低训练用时和空间成本.
基金supported in part by National Basic Research Program of China (973 Program) (Grant No. 2007CB814901)the Natural Science Foundation of Shandong Province (Grant No. ZR2009AL015)
文摘With the notion of independent identically distributed(IID) random variables under sublinear expectations introduced by Peng,we investigate moment bounds for IID sequences under sublinear expectations. We obtain a moment inequality for a sequence of IID random variables under sublinear expectations. As an application of this inequality,we get the following result:For any continuous functionsatisfying the growth condition |(x) | C(1 + |x|p) for some C > 0,p 1 depending on ,the central limit theorem under sublinear expectations obtained by Peng still holds.
基金The Agricultural Science and Technology Innovation Program (ASTIP-IAED-2021-06, STIP-IAED-2021-ZD-02)。
文摘With Globally Important Agricultural Heritage Systems(GIAHS)increasing in number around the world,their conservation has become a new international research theme.From the perspective of combining theoretical analyses and practical case applications,this study examines the Important Agricultural Heritage Systems(IAHS)conservation pathways and operation mechanisms through industrial integration development(IID).First,the theoretical framework of IID in IAHS sites was constructed according to the requirements of IAHS conservation,which include analyses of the connotation and basic principles of IID,the necessity of IID for IAHS sites,the resource conditions,and the IID pathways.And then based on the theoretical framework,the IID of Longji Terraces in Guangxi,Honghe Hani Rice Terraces System in Yunnan(HHRTS),Aohan Dryland Farming System in Inner Mongolia(ADFS),and Huzhou Mulberry-dyke&Fish-pond System(HMFS)in Zhejiang are analyzed systematically.The main finding is that IID is an effective pathway for IAHS conservation.However,the IID in IAHS sites must stress the ecological and cultural values of the resources;IID should be based on local resource advantages;and IID should attach importance to the combination of different policies and coordination between different stakeholders.
