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Directed Acyclic Graph Blockchain for Secure Spectrum Sharing and Energy Trading in Power IoT
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作者 Zixi Zhang Mingxia Zhang +2 位作者 Yu Li Bo Fan Li Jiang 《China Communications》 SCIE CSCD 2023年第5期182-197,共16页
Peer-to-peer(P2P)spectrum sharing and energy trading are promising solutions to locally satisfy spectrum and energy demands in power Internet of Things(IoT).However,implementation of largescale P2P spectrum sharing an... Peer-to-peer(P2P)spectrum sharing and energy trading are promising solutions to locally satisfy spectrum and energy demands in power Internet of Things(IoT).However,implementation of largescale P2P spectrum sharing and energy trading confronts security and privacy challenges.In this paper,we exploit consortium blockchain and Directed Acyclic Graph(DAG)to propose a new secure and distributed spectrum sharing and energy trading framework in power IoT,named spectrum-energy chain,where a set of local aggregators(LAGs)cooperatively confirm the identity of the power devices by utilizing consortium blockchain,so as to form a main chain.Then,the local power devices verify spectrum and energy micro-transactions simultaneously but asynchronously to form local spectrum tangle and local energy tangle,respectively.Moreover,an iterative double auction based micro transactions scheme is designed to solve the spectrum and energy pricing and the amount of shared spectrum and energy among power devices.Security analysis and numerical results illustrate that the developed spectrum-energy chain and the designed iterative double auction based microtransactions scheme are secure and efficient for spectrum sharing and energy trading in power IoT. 展开更多
关键词 power Internet of Things(IoT) spectrum sharing energy trading security and privacy consortium blockchain directed acyclic graph(dag) iterative double auction
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A Secure Microgrid Data Storage Strategy with Directed Acyclic Graph Consensus Mechanism
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作者 Jian Shang Runmin Guan Wei Wang 《Intelligent Automation & Soft Computing》 SCIE 2023年第9期2609-2626,共18页
The wide application of intelligent terminals in microgrids has fueled the surge of data amount in recent years.In real-world scenarios,microgrids must store large amounts of data efficiently while also being able to ... The wide application of intelligent terminals in microgrids has fueled the surge of data amount in recent years.In real-world scenarios,microgrids must store large amounts of data efficiently while also being able to withstand malicious cyberattacks.To meet the high hardware resource requirements,address the vulnerability to network attacks and poor reliability in the tradi-tional centralized data storage schemes,this paper proposes a secure storage management method for microgrid data that considers node trust and directed acyclic graph(DAG)consensus mechanism.Firstly,the microgrid data storage model is designed based on the edge computing technology.The blockchain,deployed on the edge computing server and combined with cloud storage,ensures reliable data storage in the microgrid.Secondly,a blockchain consen-sus algorithm based on directed acyclic graph data structure is then proposed to effectively improve the data storage timeliness and avoid disadvantages in traditional blockchain topology such as long chain construction time and low consensus efficiency.Finally,considering the tolerance differences among the candidate chain-building nodes to network attacks,a hash value update mechanism of blockchain header with node trust identification to ensure data storage security is proposed.Experimental results from the microgrid data storage platform show that the proposed method can achieve a private key update time of less than 5 milliseconds.When the number of blockchain nodes is less than 25,the blockchain construction takes no more than 80 mins,and the data throughput is close to 300 kbps.Compared with the traditional chain-topology-based consensus methods that do not consider node trust,the proposed method has higher efficiency in data storage and better resistance to network attacks. 展开更多
关键词 MICROGRID data security storage node trust degree directed acyclic graph data structure consensus mechanism secure multi-party computing blockchain
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Multi-Class Support Vector Machine Classifier Based on Jeffries-Matusita Distance and Directed Acyclic Graph 被引量:1
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作者 Miao Zhang Zhen-Zhou Lai +1 位作者 Dan Li Yi Shen 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2013年第5期113-118,共6页
Based on the framework of support vector machines (SVM) using one-against-one (OAO) strategy, a new multi-class kernel method based on directed aeyclie graph (DAG) and probabilistic distance is proposed to raise... Based on the framework of support vector machines (SVM) using one-against-one (OAO) strategy, a new multi-class kernel method based on directed aeyclie graph (DAG) and probabilistic distance is proposed to raise the multi-class classification accuracies. The topology structure of DAG is constructed by rearranging the nodes' sequence in the graph. DAG is equivalent to guided operating SVM on a list, and the classification performance depends on the nodes' sequence in the graph. Jeffries-Matusita distance (JMD) is introduced to estimate the separability of each class, and the implementation list is initialized with all classes organized according to certain sequence in the list. To testify the effectiveness of the proposed method, numerical analysis is conducted on UCI data and hyperspectral data. Meanwhile, comparative studies using standard OAO and DAG classification methods are also conducted and the results illustrate better performance and higher accuracy of the orooosed JMD-DAG method. 展开更多
关键词 multi-class classification support vector machine directed acyclic graph Jeffries-Matusitadistance hyperspcctral data
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An Improved Directed Acyclic Graph Support Vector Machine
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作者 Adel RHUMA Syed Mohsen NAQVI Jonathon CHAMBERS 《Journal of Measurement Science and Instrumentation》 CAS 2011年第4期367-370,共4页
In this paper, we propose an improved Directed Acyclic Graph Support Vector Machine (DAGSVM) for multi-class classification. Compared with the traditional DAGSVM, the improved version has advantages that the structu... In this paper, we propose an improved Directed Acyclic Graph Support Vector Machine (DAGSVM) for multi-class classification. Compared with the traditional DAGSVM, the improved version has advantages that the structure of the directed acyclic graph is not chosen random and fixed, and it can be adaptive to be optimal according to the incoming testing samples, thus it has a good generalization performance. From experiments on six datasets, we can see that the proposed improved version of DAGSVM is better than the traditional one with respect to the accuracy rate. 展开更多
关键词 class classification directed acyclic graph support vector machine
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基于路径存储表的Hashgraph共识算法优化与实现
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作者 刘寅昊 蒋文保 +1 位作者 孙林昆 王勇攀 《计算机工程》 CAS CSCD 北大核心 2024年第6期166-178,共13页
Hashgraph是一种数据采用有向无环图(DAG)结构的区块链共识算法,Hashgraph引入了虚拟投票的概念,允许节点在无额外通信开销的情况下并发出块,实现异步场景下的拜占庭容错。然而,Hashgraph提出的虚拟投票算法存在算法时间复杂度较高、共... Hashgraph是一种数据采用有向无环图(DAG)结构的区块链共识算法,Hashgraph引入了虚拟投票的概念,允许节点在无额外通信开销的情况下并发出块,实现异步场景下的拜占庭容错。然而,Hashgraph提出的虚拟投票算法存在算法时间复杂度较高、共识运行逻辑过于复杂等问题。为此,提出一种基于路径存储表的Hashgraph优化方案。首先,提出一种基于顶点可达表的见证人判定方法,通过存储路径的方式实时记录生成事件与历史事件的可达关系,在轮次划分阶段,通过查询顶点事件的可达信息取代回溯算法,降低见证人判断算法的时间复杂度;其次,针对顶点可达表无法跨轮次判断事件关系的问题,提出一种基于历史可达表的知名见证人判定方法,历史可达表将存储见证人与历史事件之间的可达关系,通过查询历史可达表解决知名见证人判定阶段需要反复回溯视图的问题;最后,根据顶点可达表和历史可达表改进Hashgraph中复杂的共识计算,提升算法效率,加快事件确认速度。实验结果表明,所提优化方案与Hashgraph原共识算法相比,算法运行效率提升65.76%,在吞吐量方面平均提升41.27%。 展开更多
关键词 区块链 共识算法 有向无环图 Hashgraph协议 拜占庭容错
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一种结合信任的多验证者DAG共识协议
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作者 顾彬 黄建华 +2 位作者 宁宇豪 张文韬 宫在为 《小型微型计算机系统》 CSCD 北大核心 2024年第5期1163-1172,共10页
共识协议是区块链系统中的关键,决定着系统的性能与安全性.针对现有共识协议暴露出的扩展性、吞吐量、参与门槛等问题及DAG区块链在区块选择方面的缺陷,提出一种结合信任的多验证者DAG共识协议TMVDP.首先,提出了基于多验证者的DAG结构,... 共识协议是区块链系统中的关键,决定着系统的性能与安全性.针对现有共识协议暴露出的扩展性、吞吐量、参与门槛等问题及DAG区块链在区块选择方面的缺陷,提出一种结合信任的多验证者DAG共识协议TMVDP.首先,提出了基于多验证者的DAG结构,多个验证节点共同负责数据验证,从而提高系统性能与可扩展性,同时降低对普通节点的性能需求.其次,提出了DAG结构中的区块信任度机制.通过赋予区块相应的信任度,调整不同情况下区块被引用的概率,从而解决了孤块问题,保证网络的高吞吐量与安全性.最后,针对账本构建四叉树索引,有效避免DAG结构中数据量过大带来的检索困难问题.实验结果表明TMVDP协议在保证系统安全性的前提下提高了共识效率与吞吐量,加快了区块查询速度,扩展性良好. 展开更多
关键词 区块链 共识协议 有向无环图 信誉机制 索引结构
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基于时序感知DAG的多模态对话情绪识别模型
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作者 沈旭东 黄贤英 邹世豪 《计算机应用研究》 CSCD 北大核心 2024年第1期51-58,共8页
针对现有对话情绪识别方法中对时序信息、话语者信息、多模态信息利用不充分的问题,提出了一个时序信息感知的多模态有向无环图模型(MTDAG)。其中所设计的时序感知单元能按照时间顺序优化话语权重设置,并收集历史情绪线索,实现基于近因... 针对现有对话情绪识别方法中对时序信息、话语者信息、多模态信息利用不充分的问题,提出了一个时序信息感知的多模态有向无环图模型(MTDAG)。其中所设计的时序感知单元能按照时间顺序优化话语权重设置,并收集历史情绪线索,实现基于近因效应下对时序信息和历史信息更有效的利用;设计的上下文和话语者信息融合模块,通过提取上下文语境和话语者自语境的深度联合信息实现对话语者信息的充分利用;通过设置DAG(directed acyclic graph)子图捕获多模态信息并约束交互方向的方式,在减少噪声引入的基础上充分利用多模态信息。在两个基准数据集IEMOCAP和MELD的大量实验表明该模型具有较好的情绪识别效果。 展开更多
关键词 对话情绪识别 有向无环图 近因效应 特征提取 多模态交互
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Evolution of Word-updating Dynamical Systems (WDS) on Directed Graphs
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作者 郑洁 《Journal of Donghua University(English Edition)》 EI CAS 2009年第2期132-134,共3页
This paper continues the research on theoretical foundations for computer simulation.We introduce the concept of word-updating dynamical systems(WDS)on directed graphs,which is a kind of generalization of sequential d... This paper continues the research on theoretical foundations for computer simulation.We introduce the concept of word-updating dynamical systems(WDS)on directed graphs,which is a kind of generalization of sequential dynamical systems(SDS)on graphs.Some properties on WDS,especially some results on NOR-WDS,which are different from that on NOR-SDS,are obtained. 展开更多
关键词 word-updating dynamical system WDS functional directed graph acyclic orientation
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双循环背景下人民币汇率变动的价格传递效应——基于DAG-SVAR模型的分析
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作者 赫国胜 吴睿 《沈阳师范大学学报(社会科学版)》 2023年第3期41-48,共8页
在构建双循环发展格局的战略指引和加快建设贸易强国重大战略安排的背景下,伴随着人民币汇率波动性不断增强,研究人民币汇率变动的价格传递效应具有重要意义。有向无环图(DAG)方法与SVAR模型相结合,可将变量间的同期关系纳入模型中并回... 在构建双循环发展格局的战略指引和加快建设贸易强国重大战略安排的背景下,伴随着人民币汇率波动性不断增强,研究人民币汇率变动的价格传递效应具有重要意义。有向无环图(DAG)方法与SVAR模型相结合,可将变量间的同期关系纳入模型中并回避SVAR模型约束条件设定中的主观性。实证分析使用2006年1月至2021年12月的月度数据,研究人民币汇率变动对我国进口价格、生产者价格和消费者价格的传递效应。研究结果显示:人民币汇率变动对三种价格的传递效应存在着大小和时间两方面的异质性,人民币汇率变动对进口价格的传递效应最大,对生产者价格和消费者价格的传递效应则依次递减,进口价格最先受到汇率变动的影响,对生产者价格和消费者价格的传递效应具有一定的时滞。 展开更多
关键词 双循环 汇率传递 SVAR 有向无环图
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基于DAG和改进随机线性编码的数据传输 被引量:2
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作者 程艳艳 李旸 汤永利 《计算机工程与设计》 北大核心 2023年第3期664-670,共7页
为提高无线传感器网络的数据可操作性和传输效率,提出一种基于有向无环图(DAG)模型的网络编码传输方法。开发一个生成DAG的数学模型,将簇头(CH)节点参与到DAG,仅通过CH进行编码;采用改进随机线性网络编码,降低编码复杂度;使用P2P覆盖存... 为提高无线传感器网络的数据可操作性和传输效率,提出一种基于有向无环图(DAG)模型的网络编码传输方法。开发一个生成DAG的数学模型,将簇头(CH)节点参与到DAG,仅通过CH进行编码;采用改进随机线性网络编码,降低编码复杂度;使用P2P覆盖存储系统,联合多个网关/代理,可对丢失的数据包进行恢复。实验结果表明,所提方法在临界链路位置无法预测的场景,明显提高了丢失数据包的恢复率,避免了过多数据包的传输。在数据包恢复和能消之间实现了较好平衡。 展开更多
关键词 无线传感器网络 有向无环图 网络编码 簇头 网关 随机线性编码 链路
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Advanced DAG-Based Ranking(ADR)Protocol for Blockchain Scalability
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作者 Tayyaba Noreen Qiufen Xia Muhammad Zeeshan Haider 《Computers, Materials & Continua》 SCIE EI 2023年第5期2593-2613,共21页
In the past decade,blockchain has evolved as a promising solution to develop secure distributed ledgers and has gained massive attention.However,current blockchain systems face the problems of limited throughput,poor ... In the past decade,blockchain has evolved as a promising solution to develop secure distributed ledgers and has gained massive attention.However,current blockchain systems face the problems of limited throughput,poor scalability,and high latency.Due to the failure of consensus algorithms in managing nodes’identities,blockchain technology is considered inappropriate for many applications,e.g.,in IoT environments,because of poor scalability.This paper proposes a blockchain consensus mechanism called the Advanced DAG-based Ranking(ADR)protocol to improve blockchain scalability and throughput.The ADR protocol uses the directed acyclic graph ledger,where nodes are placed according to their ranking positions in the graph.It allows honest nodes to use theDirect Acyclic Graph(DAG)topology to write blocks and verify transactions instead of a chain of blocks.By using a three-step strategy,this protocol ensures that the system is secured against doublespending attacks and allows for higher throughput and scalability.The first step involves the safe entry of nodes into the system by verifying their private and public keys.The next step involves developing an advanced DAG ledger so nodes can start block production and verify transactions.In the third step,a ranking algorithm is developed to separate the nodes created by attackers.After eliminating attacker nodes,the nodes are ranked according to their performance in the system,and true nodes are arranged in blocks in topological order.As a result,the ADR protocol is suitable for applications in the Internet of Things(IoT).We evaluated ADR on EC2 clusters with more than 100 nodes and achieved better transaction throughput and liveness of the network while adding malicious nodes.Based on the simulation results,this research determined that the transaction’s performance was significantly improved over blockchains like Internet of Things Applications(IOTA)and ByteBall. 展开更多
关键词 Blockchain SCALABILITY directed acyclic graph advanced dag-based ranking protocol
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基于径向基核函数DAG-SVM的变压器故障诊断 被引量:1
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作者 刘锐 殷嘉伟 +1 位作者 胡宗义 杨彪 《价值工程》 2023年第23期44-46,共3页
本文将有向无环图(Directed Acyclic Graph,DAG)结构和支持向量机(Support Vector Machine,SVM)的分类能力相结合,提出一种基于径向基核函数DAG-SVM的变压器故障诊断方法。通过使用径向基核函数,DAG-SVM能够将非线性特征映射到高维空间... 本文将有向无环图(Directed Acyclic Graph,DAG)结构和支持向量机(Support Vector Machine,SVM)的分类能力相结合,提出一种基于径向基核函数DAG-SVM的变压器故障诊断方法。通过使用径向基核函数,DAG-SVM能够将非线性特征映射到高维空间,并在该空间中进行分类,从而更好地捕捉变压器故障的复杂模式和特征。数值计算结果表明,基于径向基核函数的故障诊断综合正确率为73.88%,均高于线性核函数、多项式核函数、S型核函数三种方法,所提基于径向基核函数DAG-SVM的变压器故障诊断模型具有较好的诊断效果。 展开更多
关键词 变压器 支持向量机 故障诊断 径向基核函数 有向无环图
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公开选举代表投票的DAG共识机制
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作者 王云丽 寻湘楚 姚昱旻 《计算机系统应用》 2023年第1期119-126,共8页
区块链作为一种创新型的分布式账本技术,以其去中心化、可追溯、防篡改等特性,在未来许多行业中具有广泛的应用前景.但现有单链式结构的区块链存在并发低、高延迟等问题.一种基于有向无环图(directed acyclic graph,DAG)结构的新型账本... 区块链作为一种创新型的分布式账本技术,以其去中心化、可追溯、防篡改等特性,在未来许多行业中具有广泛的应用前景.但现有单链式结构的区块链存在并发低、高延迟等问题.一种基于有向无环图(directed acyclic graph,DAG)结构的新型账本技术的出现有望突破传统区块链的性能瓶颈,但目前基于DAG型区块链系统的共识机制并不成熟.本文针对典型DAG型区块链系统Nano网络的ORV共识机制存在的安全性问题进行改进,提出了一种基于代表选举模型的公开选举代表投票共识机制,即OERV(open election representative voting).使主要代表节点的权益得到了分散,增强了去中心化程度,提高了网络安全性.实验结果表明,OERV算法性能高效,能够在不牺牲系统效率的同时增强系统的稳定性和安全性,对于推动DAG型区块链共识机制的研究有着重要的现实意义. 展开更多
关键词 有向无环图(dag) 区块链 共识算法
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大数据DAG任务流调度平台技术研究与应用
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作者 许佳裕 《计算机应用文摘》 2023年第11期57-59,共3页
文章提出了一种大数据DAG任务流调度平台技术,其能够基于DAG任务流进行调度,以及对大数据处理流程进行调度。为了实现这一目的,文章从几个方面进行详细设计,即架构设计、协议设计、引擎设计、引擎热加载机制、DAG结构、资源介质机制、... 文章提出了一种大数据DAG任务流调度平台技术,其能够基于DAG任务流进行调度,以及对大数据处理流程进行调度。为了实现这一目的,文章从几个方面进行详细设计,即架构设计、协议设计、引擎设计、引擎热加载机制、DAG结构、资源介质机制、调度算法、回调机制、信号机制。使用基于拖拽的方式进行流程配置,降低用户的使用难度,最终实现在企业实时/离线大数据处理流程中承担所有任务调度工作。 展开更多
关键词 大数据 dag有向无环图 调度平台
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胆总管结石患者ERCP术后早期胆道感染的动态预测工具开发及验证
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作者 李鹏 梁超 +4 位作者 颜家凤 高春辉 马志杰 谢占涛 孙明洁 《中国感染控制杂志》 CAS CSCD 北大核心 2024年第6期692-699,共8页
目的开发胆总管结石患者经内镜逆行性胰胆管造影术(ERCP)后发生早期胆道感染(PEEBI)的预测工具,以期辅助临床进行ERCP术前决策和术后早期个性化干预。方法采用观察性双向队列研究方法,选取某医院接受ERCP的胆总管结石住院患者,分别采用... 目的开发胆总管结石患者经内镜逆行性胰胆管造影术(ERCP)后发生早期胆道感染(PEEBI)的预测工具,以期辅助临床进行ERCP术前决策和术后早期个性化干预。方法采用观察性双向队列研究方法,选取某医院接受ERCP的胆总管结石住院患者,分别采用有向无环图(DAGs)和最小绝对收缩与选择算子法(LASSO)进行基于logistic回归的PEEBI预测,比较预测模型,并进行内外部验证。结果2020年1月1日—2023年9月30日,共纳入接受ERCP的胆总管结石患者2121例,其中77例(3.6%)发生了PEEBI,且主要集中在术后前2天(66.2%)。影响PEEBI的主要因素为非医源的患者相关因素,即糖尿病(OR=2.43,95%CI:1.14~4.85)、胆管恶性肿瘤(OR=3.95,95%CI:1.74~8.31)和十二指肠乳头憩室(OR=4.39,95%CI:1.86~9.52)。DAGs模型较LASSO模型的综合判别能力高3.0%(P=0.007),且DAGs模型外部验证中的区分性能(D=0.133,P=0.894)和校准性能(χ^(2)=5.499,P=0.703)均表现良好。结论本研究构建的DAGs模型具有良好的预测性能,临床可在该工具的协助下采取针对性的围手术期早期预防措施,以减少PEEBI的发生。 展开更多
关键词 胆总管结石 经内镜逆行性胰胆管造影术 胆道感染 有向无环图 预测
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车联网中基于有向无环图区块链的个性化联邦互蒸馏学习方法
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作者 黄晓舸 吴雨航 +2 位作者 尹宏博 梁承超 陈前斌 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第7期2821-2830,共10页
联邦学习(FL)作为一种分布式训练方法,在车联网(IoV)中得到了广泛应用。区别于传统机器学习,FL允许智能网联车辆(CAVs)通过共享模型而非原始数据来协同训练全局模型,从而保护CAV隐私和数据安全。为了提升联邦学习模型精度,降低通信开销... 联邦学习(FL)作为一种分布式训练方法,在车联网(IoV)中得到了广泛应用。区别于传统机器学习,FL允许智能网联车辆(CAVs)通过共享模型而非原始数据来协同训练全局模型,从而保护CAV隐私和数据安全。为了提升联邦学习模型精度,降低通信开销,该文首先提出一种基于有向无环图(DAG)区块链和CAVs的IoV架构,分别负责全局模型共享和本地模型训练。其次,设计了一种基于DAG区块链的异步联邦互蒸馏学习(DAFML)算法在本地同时训练教师和学生模型,教师模型的专业级网络结构可取得更高精度,学生模型的轻量级网络结构可降低通信开销,并采用互蒸馏学习使教师模型和学生模型从互相转移的软标签中学习知识以更新模型。此外,为了进一步提高模型精度,基于全局训练轮次和模型精度设定个性化权值来调节互蒸馏占比。仿真结果表明,DAFML算法在模型精度和蒸馏比率方面优于其他比较算法。 展开更多
关键词 联邦学习 互蒸馏 有向无环图 个性化权值
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Cloud-based parallel power flow calculation using resilient distributed datasets and directed acyclic graph 被引量:4
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作者 Dewen WANG Fangfang ZHOU Jiangman LI 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2019年第1期65-77,共13页
With the integration of distributed generation and the construction of cross-regional long-distance power grids, power systems become larger and more complex.They require faster computing speed and better scalability ... With the integration of distributed generation and the construction of cross-regional long-distance power grids, power systems become larger and more complex.They require faster computing speed and better scalability for power flow calculations to support unit dispatch.Based on the analysis of a variety of parallelization methods, this paper deploys the large-scale power flow calculation task on a cloud computing platform using resilient distributed datasets(RDDs).It optimizes a directed acyclic graph that is stored in the RDDs to solve the low performance problem of the MapReduce model.This paper constructs and simulates a power flow calculation on a large-scale power system based on standard IEEE test data.Experiments are conducted on Spark cluster which is deployed as a cloud computing platform.They show that the advantages of this method are not obvious at small scale, but the performance is superior to the stand-alone model and the MapReduce model for large-scale calculations.In addition, running time will be reduced when adding cluster nodes.Although not tested under practical conditions, this paper provides a new way of thinking about parallel power flow calculations in large-scale power systems. 展开更多
关键词 Power flow calculation PARALLEL programming MODEL DISTRIBUTED memory-shared MODEL Resilient DISTRIBUTED datasets(RDDs) directed acyclic graph(dag)
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Electromagnetic side-channel attack based on PSO directed acyclic graph SVM 被引量:3
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作者 Li Duan Zhang Hongxin +2 位作者 Li Qiang Zhao Xinjie He Pengfei 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2015年第5期10-15,共6页
Machine learning has a powerful potential for performing the template attack(TA) of cryptographic device. To improve the accuracy and time consuming of electromagnetic template attack(ETA), a multi-class directed acyc... Machine learning has a powerful potential for performing the template attack(TA) of cryptographic device. To improve the accuracy and time consuming of electromagnetic template attack(ETA), a multi-class directed acyclic graph support vector machine(DAGSVM) method is proposed to predict the Hamming weight of the key. The method needs to generate K(K ? 1)/2 binary support vector machine(SVM) classifiers and realizes the K-class prediction using a rooted binary directed acyclic graph(DAG) testing model. Further, particle swarm optimization(PSO) is used for optimal selection of DAGSVM model parameters to improve the performance of DAGSVM. By exploiting the electromagnetic emanations captured while a chip was implementing the RC4 algorithm in software, the computation complexity and performance of several multi-class machine learning methods, such as DAGSVM, one-versus-one(OVO)SVM, one-versus-all(OVA)SVM, Probabilistic neural networks(PNN), K-means clustering and fuzzy neural network(FNN) are investigated. In the same scenario, the highest classification accuracy of Hamming weight for the key reached 100%, 95.33%, 85%, 74%, 49.67% and 38% for DAGSVM, OVOSVM, OVASVM, PNN, K-means and FNN, respectively. The experiment results demonstrate the proposed model performs higher predictive accuracy and faster convergence speed. 展开更多
关键词 directed acyclic graph support vector machine(dagS
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一种基于模糊聚类的网格DAG任务图调度算法 被引量:48
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作者 杜晓丽 蒋昌俊 +1 位作者 徐国荣 丁志军 《软件学报》 EI CSCD 北大核心 2006年第11期2277-2288,共12页
针对网格环境中,任务调度的目标系统具有规模庞大、分布异构和动态性等特点,提出一种基于模糊聚类的网格异构任务调度算法.以往的很多调度算法需要在调度的每一步遍历整个目标系统,虽然能够获得较小的makespan,但是无疑增加了整个调度的... 针对网格环境中,任务调度的目标系统具有规模庞大、分布异构和动态性等特点,提出一种基于模糊聚类的网格异构任务调度算法.以往的很多调度算法需要在调度的每一步遍历整个目标系统,虽然能够获得较小的makespan,但是无疑增加了整个调度的Runtime.定义了一组刻画处理单元综合性能的特征,利用模糊聚类方法对目标系统(处理单元网络)进行预处理,实现了对处理单元网络的合理划分,使得在任务调度时能够较准确地优先选择综合性能较好的处理单元聚类,从而缩小搜索空间,大量减少任务调度时选择处理单元的时间耗费.此外,就绪任务优先级的构造既隐含考虑了关键路径上节点的执行情况对整个程序执行的影响,又考虑了异构资源对任务执行的影响.实验及性能分析比较的结果表明,定义的处理器特征能够实现对处理器网络的合理划分,而且随着目标系统规模的增大,所提出的算法优越性越来越明显. 展开更多
关键词 网格 dag(direct acyclic grapb) 任务调度 模糊聚类 异构计算环境
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基于节点选择优化的DAG-SVM多类别分类 被引量:9
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作者 沈健 蒋芸 +2 位作者 邹丽 陈娜 胡学伟 《计算机工程》 CAS CSCD 北大核心 2015年第6期143-146,共4页
有向无环图支持向量机(DAG-SVM)对于N类别分类问题,会构造N×(N-1)/2个支持向量机分类器(为每2个类构造一个支持向量机),DAG-SVM可能出现由于节点选择不佳而导致整个分类器分类结果较差的情况。为此,提出一种改进的DAG-SVM。通过为... 有向无环图支持向量机(DAG-SVM)对于N类别分类问题,会构造N×(N-1)/2个支持向量机分类器(为每2个类构造一个支持向量机),DAG-SVM可能出现由于节点选择不佳而导致整个分类器分类结果较差的情况。为此,提出一种改进的DAG-SVM。通过为每一层建立备选节点集合进行节点选择,选取下层备选节点集合中训练分类精度最高的一个节点组合作为当前层节点的下层节点,从而优化DAG-SVM的拓扑结构。实验结果表明,与已有的DAG-SVM,1-vs-1SVM,1-vs-a SVM方法相比,该方法的分类精度较高。 展开更多
关键词 有向无环图支持向量机 分类器 多类别分类 节点选择优化 备选节点
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