Identifying influential nodes in complex networks is of both theoretical and practical importance. Existing methods identify influential nodes based on their positions in the network and assume that the nodes are homo...Identifying influential nodes in complex networks is of both theoretical and practical importance. Existing methods identify influential nodes based on their positions in the network and assume that the nodes are homogeneous. However, node heterogeneity （i.e., different attributes such as interest, energy, age, and so on ） ubiquitously exists and needs to be taken into consideration. In this paper, we conduct an investigation into node attributes and propose a graph signal pro- cessing based centrality （GSPC） method to identify influential nodes considering both the node attributes and the network topology. We first evaluate our GSPC method using two real-world datasets. The results show that our GSPC method effectively identifies influential nodes, which correspond well with the underlying ground truth. This is compatible to the previous eigenvector centrality and principal component centrality methods under circumstances where the nodes are homogeneous. In addition, spreading analysis shows that the GSPC method has a positive effect on the spreading dynamics.展开更多
The networks are fundamental to our modern world and they appear throughout science and society.Access to a massive amount of data presents a unique opportunity to the researcher’s community.As networks grow in size ...The networks are fundamental to our modern world and they appear throughout science and society.Access to a massive amount of data presents a unique opportunity to the researcher’s community.As networks grow in size the complexity increases and our ability to analyze them using the current state of the art is at severe risk of failing to keep pace.Therefore,this paper initiates a discussion on graph signal processing for large-scale data analysis.We first provide a comprehensive overview of core ideas in Graph signal processing(GSP)and their connection to conventional digital signal processing(DSP).We then summarize recent developments in developing basic GSP tools,including methods for graph filtering or graph learning,graph signal,graph Fourier transform(GFT),spectrum,graph frequency,etc.Graph filtering is a basic task that allows for isolating the contribution of individual frequencies and therefore enables the removal of noise.We then consider a graph filter as a model that helps to extend the application of GSP methods to large datasets.To show the suitability and the effeteness,we first created a noisy graph signal and then applied it to the filter.After several rounds of simulation results.We see that the filtered signal appears to be smoother and is closer to the original noise-free distance-based signal.By using this example application,we thoroughly demonstrated that graph filtration is efficient for big data analytics.展开更多
In the graph signal processing(GSP)framework,distributed algorithms are highly desirable in processing signals defined on large-scale networks.However,in most existing distributed algorithms,all nodes homogeneously pe...In the graph signal processing(GSP)framework,distributed algorithms are highly desirable in processing signals defined on large-scale networks.However,in most existing distributed algorithms,all nodes homogeneously perform the local computation,which calls for heavy computational and communication costs.Moreover,in many real-world networks,such as those with straggling nodes,the homogeneous manner may result in serious delay or even failure.To this end,we propose active network decomposition algorithms to select non-straggling nodes(normal nodes)that perform the main computation and communication across the network.To accommodate the decomposition in different kinds of networks,two different approaches are developed,one is centralized decomposition that leverages the adjacency of the network and the other is distributed decomposition that employs the indicator message transmission between neighboring nodes,which constitutes the main contribution of this paper.By incorporating the active decomposition scheme,a distributed Newton method is employed to solve the least squares problem in GSP,where the Hessian inverse is approximately evaluated by patching a series of inverses of local Hessian matrices each of which is governed by one normal node.The proposed algorithm inherits the fast convergence of the second-order algorithms while maintains low computational and communication cost.Numerical examples demonstrate the effectiveness of the proposed algorithm.展开更多
船舶在运行过程中,易因设备老化、操作失误或其他突发事件影响造成电力系统通信系统损伤,导致电力系统关键数据缺失,影响系统的正常运行和安全态势的准确感知。针对现有电力系统缺失数据恢复算法速度较慢且还原精度较低的问题,提出一种...船舶在运行过程中,易因设备老化、操作失误或其他突发事件影响造成电力系统通信系统损伤,导致电力系统关键数据缺失,影响系统的正常运行和安全态势的准确感知。针对现有电力系统缺失数据恢复算法速度较慢且还原精度较低的问题,提出一种基于少量量测信息的超分辨率量测生成方法。根据电力系统量测配置分布空间分布不均且量测精度不同的特点构建电力系统空间稀疏量测状态方程,结合图傅里叶分解技术构建电压的低维近似等式来减少参数量,进而实现低阶线性的近似利用,通过引入掩码概念,构造基于图信号处理的状态估计优化方程,实现了配电网电压的快速重建并提高了全局电压的质量。通过IEEE-85节点算例验证,所提方法相较半正定规划最小二乘法(Semi-Definite Programming Least Squares,SDP-SE)、矩阵补全方法在不同量测数量下的电压恢复精度平均提升50%,相较SDP-SE在运算时间上从分钟级降低至秒级,支持系统在线运行。在Cloudpss中搭建船舶电力系统模型并进行实验,在2 s内实现了缺失电压的数据恢复,且电压的平均绝对误差为0.88%,验证了该方法在船舶电力系统通信系统部分损毁的情况下,能够准确掌握全局信息,提高系统的抗干扰能力和自愈能力。展开更多
无线光通信网络的隐蔽窃听攻击具有高度的隐蔽性和复杂性,其中包含的复杂数据模式和特征,加大了无线光通信网络隐蔽窃听攻击检测难度。故提出无线光通信网络隐蔽窃听攻击自适应检测研究。采用图信号处理方法全面监测无线光通信网络,捕...无线光通信网络的隐蔽窃听攻击具有高度的隐蔽性和复杂性,其中包含的复杂数据模式和特征,加大了无线光通信网络隐蔽窃听攻击检测难度。故提出无线光通信网络隐蔽窃听攻击自适应检测研究。采用图信号处理方法全面监测无线光通信网络,捕捉异常信号范围;利用人工智能技术识别隐蔽窃听攻击特征;建立基于混合核最小二乘支持向量机(hybridkernel least-squares support vector machine,HKLSSVM)的窃听攻击检测模型,通过引入混合核函数将数据映射到更高维的特征空间中,识别出的隐蔽窃听攻击特征,并通过鲸鱼提升算法选择最优的惩罚参数和内核参数,实现无线光通信网络隐蔽窃听攻击自适应检测。实验结果表明,所提方法能准确获取异常信号范围和异常信号,在保证计算稳定性的同时,提高攻击检测性能。展开更多
点云的处理、传输、语义分割等是3维计算机视觉领域重要的分析任务.现如今,图神经网络和图结构在点云研究方面的有效性已被证实,基于图的点云(graph-based point cloud,GPC)研究不断涌现.因此,一种统一的研究角度、框架和方法论亟待形成...点云的处理、传输、语义分割等是3维计算机视觉领域重要的分析任务.现如今,图神经网络和图结构在点云研究方面的有效性已被证实,基于图的点云(graph-based point cloud,GPC)研究不断涌现.因此,一种统一的研究角度、框架和方法论亟待形成.系统性梳理了GPC研究的各种应用场景,包括配准、降噪、压缩、表示学习、分类、分割、检测等任务,概括出GPC研究的一般性框架,提出了一条覆盖当前GPC全域研究的技术路线.具体来说,给出了GPC研究的分层概念范畴,包括底层数据处理、中层表示学习、高层识别任务;综述了各领域中的GPC模型或算法,包括静态和动态点云的处理算法、有监督和无监督的表示学习模型、传统或机器学习的GPC识别算法;总结了其中代表性的成果及其核心思想,譬如动态更新每层特征空间对应的最近邻图、分层以及参数共享的动态点聚合模块,结合图划分和图卷积提高分割精度;对比了模型性能,包括总体精度(overall accuracy,OA)、平均精度(mean accuracy,mAcc)、平均交并比(mean intersection over union,mIoU);在分析比较现有模型和方法的基础上,归纳了GPC目前面临的主要挑战,提出相应的研究问题,并展望未来的研究方向.建立的GPC研究框架具有一般性和通用性,为后续研究者从事GPC这个新型交叉领域研究提供了领域定位、技术总结及宏观视角.点云研究的出现,是探测器硬件技术长足进步后应运而生的结果;点云研究的现状表明在理论和实践之间存在一些挑战,一些关键问题还有待解决.同时,点云研究的发展将推动人工智能进入新的时代.展开更多
波达方向(Direction of Arrival,DOA)估计技术是语音增强和声学探测中的重要工具,对于语音机器人、视频会议、助听器和声呐等应用至关重要。最近出现的DOA估计新方法,例如图信号处理(Graph Signal Processing,GSP)方法,展现出优异的角...波达方向(Direction of Arrival,DOA)估计技术是语音增强和声学探测中的重要工具,对于语音机器人、视频会议、助听器和声呐等应用至关重要。最近出现的DOA估计新方法,例如图信号处理(Graph Signal Processing,GSP)方法,展现出优异的角度估计能力,有望提供更佳的声源DOA估计解决方案。然而,由于在多声源情况下GSP算法由邻接矩阵无法直接得到接收信号特征向量的正交补矩阵,导致多声源下GSP算法失效。为解决此问题,本文基于多源宽带语音信号的频域单源区域检测实现多声源分离,进而利用GSP和聚类算法实现宽带多声源的定位。具体而言,本文首先将GSP方法扩展到频域。其次,利用短时傅里叶变换将信号分为若干时频区域,筛选出单源主导的时频区域后,对其进行频域GSP单源定位。最后,对所有定位结果进行聚类,再通过加权平均获得最终的角度估计。我们利用LibriSpeech语音语料库构建声源信号进行多声源定位仿真,仿真结果证明,本文方法优于其他算法,较高信噪比下可将误差控制在3°以内。此外,我们使用圆形六阵元麦克风阵列,对实际录制的若干组录音数据应用所提算法进行定位测量,结果展示所提算法的定位误差更小,并在声源较为靠近时也能做到较好的分辨。展开更多
首先论述新型图信号处理(Graph Signal Processing,GSP)技术的基本概念和相关研究进展,其中包括图拓扑结构、图傅里叶变换、滤波及图学习。鉴于语音信号是一种非平稳和非线性的信号,为此,文中研究基于GSP技术的语音信号的图映射理论,即...首先论述新型图信号处理(Graph Signal Processing,GSP)技术的基本概念和相关研究进展,其中包括图拓扑结构、图傅里叶变换、滤波及图学习。鉴于语音信号是一种非平稳和非线性的信号,为此,文中研究基于GSP技术的语音信号的图映射理论,即将时域语音信号映射为图域的语音图信号,通过设计语音图信号的图拓扑结构和图邻接矩阵来研究语音图信号的内在潜藏关系,进而设计优于经典DSP的语音图信号消噪算法和系统。在此研究基础上,进一步讨论相关实际应用问题,例如麦克风阵列环境下如何通过GSP技术处理麦克风阵列声源(说话人)的定位及追踪问题。期望基于GSP技术语音图信号处理理论,为语音识别、合成、编码、增强等各个领域的图信号处理奠定理论基础。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61231010)the Fundamental Research Funds for the Central Universities,China(Grant No.HUST No.2012QN076)
文摘Identifying influential nodes in complex networks is of both theoretical and practical importance. Existing methods identify influential nodes based on their positions in the network and assume that the nodes are homogeneous. However, node heterogeneity （i.e., different attributes such as interest, energy, age, and so on ） ubiquitously exists and needs to be taken into consideration. In this paper, we conduct an investigation into node attributes and propose a graph signal pro- cessing based centrality （GSPC） method to identify influential nodes considering both the node attributes and the network topology. We first evaluate our GSPC method using two real-world datasets. The results show that our GSPC method effectively identifies influential nodes, which correspond well with the underlying ground truth. This is compatible to the previous eigenvector centrality and principal component centrality methods under circumstances where the nodes are homogeneous. In addition, spreading analysis shows that the GSPC method has a positive effect on the spreading dynamics.
基金supported in part by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2019R1A2C1006159)and(NRF-2021R1A6A1A03039493)by the 2021 Yeungnam University Research Grant.
文摘The networks are fundamental to our modern world and they appear throughout science and society.Access to a massive amount of data presents a unique opportunity to the researcher’s community.As networks grow in size the complexity increases and our ability to analyze them using the current state of the art is at severe risk of failing to keep pace.Therefore,this paper initiates a discussion on graph signal processing for large-scale data analysis.We first provide a comprehensive overview of core ideas in Graph signal processing(GSP)and their connection to conventional digital signal processing(DSP).We then summarize recent developments in developing basic GSP tools,including methods for graph filtering or graph learning,graph signal,graph Fourier transform(GFT),spectrum,graph frequency,etc.Graph filtering is a basic task that allows for isolating the contribution of individual frequencies and therefore enables the removal of noise.We then consider a graph filter as a model that helps to extend the application of GSP methods to large datasets.To show the suitability and the effeteness,we first created a noisy graph signal and then applied it to the filter.After several rounds of simulation results.We see that the filtered signal appears to be smoother and is closer to the original noise-free distance-based signal.By using this example application,we thoroughly demonstrated that graph filtration is efficient for big data analytics.
基金supported by National Natural Science Foundation of China(Grant No.61761011)Natural Science Foundation of Guangxi(Grant No.2020GXNSFBA297078).
文摘In the graph signal processing(GSP)framework,distributed algorithms are highly desirable in processing signals defined on large-scale networks.However,in most existing distributed algorithms,all nodes homogeneously perform the local computation,which calls for heavy computational and communication costs.Moreover,in many real-world networks,such as those with straggling nodes,the homogeneous manner may result in serious delay or even failure.To this end,we propose active network decomposition algorithms to select non-straggling nodes(normal nodes)that perform the main computation and communication across the network.To accommodate the decomposition in different kinds of networks,two different approaches are developed,one is centralized decomposition that leverages the adjacency of the network and the other is distributed decomposition that employs the indicator message transmission between neighboring nodes,which constitutes the main contribution of this paper.By incorporating the active decomposition scheme,a distributed Newton method is employed to solve the least squares problem in GSP,where the Hessian inverse is approximately evaluated by patching a series of inverses of local Hessian matrices each of which is governed by one normal node.The proposed algorithm inherits the fast convergence of the second-order algorithms while maintains low computational and communication cost.Numerical examples demonstrate the effectiveness of the proposed algorithm.
文摘船舶在运行过程中,易因设备老化、操作失误或其他突发事件影响造成电力系统通信系统损伤,导致电力系统关键数据缺失,影响系统的正常运行和安全态势的准确感知。针对现有电力系统缺失数据恢复算法速度较慢且还原精度较低的问题,提出一种基于少量量测信息的超分辨率量测生成方法。根据电力系统量测配置分布空间分布不均且量测精度不同的特点构建电力系统空间稀疏量测状态方程,结合图傅里叶分解技术构建电压的低维近似等式来减少参数量,进而实现低阶线性的近似利用,通过引入掩码概念,构造基于图信号处理的状态估计优化方程,实现了配电网电压的快速重建并提高了全局电压的质量。通过IEEE-85节点算例验证,所提方法相较半正定规划最小二乘法(Semi-Definite Programming Least Squares,SDP-SE)、矩阵补全方法在不同量测数量下的电压恢复精度平均提升50%,相较SDP-SE在运算时间上从分钟级降低至秒级,支持系统在线运行。在Cloudpss中搭建船舶电力系统模型并进行实验,在2 s内实现了缺失电压的数据恢复,且电压的平均绝对误差为0.88%,验证了该方法在船舶电力系统通信系统部分损毁的情况下,能够准确掌握全局信息,提高系统的抗干扰能力和自愈能力。
文摘无线光通信网络的隐蔽窃听攻击具有高度的隐蔽性和复杂性,其中包含的复杂数据模式和特征,加大了无线光通信网络隐蔽窃听攻击检测难度。故提出无线光通信网络隐蔽窃听攻击自适应检测研究。采用图信号处理方法全面监测无线光通信网络,捕捉异常信号范围;利用人工智能技术识别隐蔽窃听攻击特征;建立基于混合核最小二乘支持向量机(hybridkernel least-squares support vector machine,HKLSSVM)的窃听攻击检测模型,通过引入混合核函数将数据映射到更高维的特征空间中,识别出的隐蔽窃听攻击特征,并通过鲸鱼提升算法选择最优的惩罚参数和内核参数,实现无线光通信网络隐蔽窃听攻击自适应检测。实验结果表明,所提方法能准确获取异常信号范围和异常信号,在保证计算稳定性的同时,提高攻击检测性能。
文摘点云的处理、传输、语义分割等是3维计算机视觉领域重要的分析任务.现如今,图神经网络和图结构在点云研究方面的有效性已被证实,基于图的点云(graph-based point cloud,GPC)研究不断涌现.因此,一种统一的研究角度、框架和方法论亟待形成.系统性梳理了GPC研究的各种应用场景,包括配准、降噪、压缩、表示学习、分类、分割、检测等任务,概括出GPC研究的一般性框架,提出了一条覆盖当前GPC全域研究的技术路线.具体来说,给出了GPC研究的分层概念范畴,包括底层数据处理、中层表示学习、高层识别任务;综述了各领域中的GPC模型或算法,包括静态和动态点云的处理算法、有监督和无监督的表示学习模型、传统或机器学习的GPC识别算法;总结了其中代表性的成果及其核心思想,譬如动态更新每层特征空间对应的最近邻图、分层以及参数共享的动态点聚合模块,结合图划分和图卷积提高分割精度;对比了模型性能,包括总体精度(overall accuracy,OA)、平均精度(mean accuracy,mAcc)、平均交并比(mean intersection over union,mIoU);在分析比较现有模型和方法的基础上,归纳了GPC目前面临的主要挑战,提出相应的研究问题,并展望未来的研究方向.建立的GPC研究框架具有一般性和通用性,为后续研究者从事GPC这个新型交叉领域研究提供了领域定位、技术总结及宏观视角.点云研究的出现,是探测器硬件技术长足进步后应运而生的结果;点云研究的现状表明在理论和实践之间存在一些挑战,一些关键问题还有待解决.同时,点云研究的发展将推动人工智能进入新的时代.
文摘波达方向(Direction of Arrival,DOA)估计技术是语音增强和声学探测中的重要工具,对于语音机器人、视频会议、助听器和声呐等应用至关重要。最近出现的DOA估计新方法,例如图信号处理(Graph Signal Processing,GSP)方法,展现出优异的角度估计能力,有望提供更佳的声源DOA估计解决方案。然而,由于在多声源情况下GSP算法由邻接矩阵无法直接得到接收信号特征向量的正交补矩阵,导致多声源下GSP算法失效。为解决此问题,本文基于多源宽带语音信号的频域单源区域检测实现多声源分离,进而利用GSP和聚类算法实现宽带多声源的定位。具体而言,本文首先将GSP方法扩展到频域。其次,利用短时傅里叶变换将信号分为若干时频区域,筛选出单源主导的时频区域后,对其进行频域GSP单源定位。最后,对所有定位结果进行聚类,再通过加权平均获得最终的角度估计。我们利用LibriSpeech语音语料库构建声源信号进行多声源定位仿真,仿真结果证明,本文方法优于其他算法,较高信噪比下可将误差控制在3°以内。此外,我们使用圆形六阵元麦克风阵列,对实际录制的若干组录音数据应用所提算法进行定位测量,结果展示所提算法的定位误差更小,并在声源较为靠近时也能做到较好的分辨。
文摘首先论述新型图信号处理(Graph Signal Processing,GSP)技术的基本概念和相关研究进展,其中包括图拓扑结构、图傅里叶变换、滤波及图学习。鉴于语音信号是一种非平稳和非线性的信号,为此,文中研究基于GSP技术的语音信号的图映射理论,即将时域语音信号映射为图域的语音图信号,通过设计语音图信号的图拓扑结构和图邻接矩阵来研究语音图信号的内在潜藏关系,进而设计优于经典DSP的语音图信号消噪算法和系统。在此研究基础上,进一步讨论相关实际应用问题,例如麦克风阵列环境下如何通过GSP技术处理麦克风阵列声源(说话人)的定位及追踪问题。期望基于GSP技术语音图信号处理理论,为语音识别、合成、编码、增强等各个领域的图信号处理奠定理论基础。
