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A NEW METHOD TO FIND CHROMATIC POLYNOMIAL OF GRAPH AND ITS APPLICATIONS 被引量:35
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作者 刘儒英 《Chinese Science Bulletin》 SCIE EI CAS 1987年第21期1508-1509,共2页
Let G be a simple graph, and let f(G, t) be its chromatic polynomial. We
关键词 CHROMATIC subgraph polynomial WRITE FIND SPANNING LETTER
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图论与复杂网络 被引量:14
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作者 段志生 《力学进展》 EI CSCD 北大核心 2008年第6期702-712,共11页
近10年来迅猛发展起来的复杂网络理论为研究复杂性与复杂系统科学提供了一个重要支撑点,它高度概括了复杂系统的重要特征,无论是在理论还是在应用方面都具有很强的生命力,而且在各个方面都得到了很大发展.重点讨论图论在复杂网络中的应... 近10年来迅猛发展起来的复杂网络理论为研究复杂性与复杂系统科学提供了一个重要支撑点,它高度概括了复杂系统的重要特征,无论是在理论还是在应用方面都具有很强的生命力,而且在各个方面都得到了很大发展.重点讨论图论在复杂网络中的应用,特别是代数图论在复杂网络同步问题中的应用.首先给出一些图的最小非零与最大特征值以及同步能力的估计,并且讨论了图与图特征向量在同步能力估计中的作用.其次以两个简单图指出同步能力与网络结构参数的关系复杂,并给出补图与加边对同步研究的意义,然后给出图运算在复杂网络同步中的作用.最后从图论与控制理论角度展望了复杂网络领域未来可能的发展方向. 展开更多
关键词 复杂网络 同步 图论 子图 补图 图运算
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基于噪声点云的三维场景重建方法 被引量:12
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作者 张健 李新乐 +3 位作者 宋莹 王仁 朱凡 赵晓燕 《计算机工程与设计》 北大核心 2020年第4期972-977,共6页
为解决深度相机数据噪声导致的过平滑、细节部分精度不够等问题,提出一种基于点云的三维重建方法。采用基于带概率模型的点云设计全局的位姿估计方法用于模型的表达与聚合;设计基于场景特征的子图划分方法,减少冗余子图,使用基于点云的... 为解决深度相机数据噪声导致的过平滑、细节部分精度不够等问题,提出一种基于点云的三维重建方法。采用基于带概率模型的点云设计全局的位姿估计方法用于模型的表达与聚合;设计基于场景特征的子图划分方法,减少冗余子图,使用基于点云的方法进行位姿图优化,实现子图构建;采用基于GPU加速的FPFH算法,从点云上提取特征点进行匹配,提高闭环检测实时性。实验结果表明,该方法可以显著提高模型的质量,在闭环检测上有更高的鲁棒性。 展开更多
关键词 深度相机 三维建模 点云 子图 闭环检测
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(mg+m-1,mf-m+1)-图的(g,f)-因子 被引量:9
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作者 刘桂真 孙铮 《数学进展》 CSCD 北大核心 1999年第4期323-330,共8页
本文证明了(mg+m-1,mf—m+1)-图具有一些特殊的(g,f)-因子,从而推广了关于(g,f)-覆盖图和(g,f)-消去图的有关结果,有助于进一步研究(mg+m—1,mf—m+1)-图的正交因子分解问题.
关键词 子图 简单图 因子分解 图论 覆盖图 消去图
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计数一阶相关免疫布尔函数 被引量:8
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作者 张建州 游志胜 《电子科学学刊》 EI CSCD 2000年第2期205-209,共5页
基于列平衡矩阵的概念,利用组合数学中的容斥原理和图论中的子图概念,给出了在流密码学中有重要应用的一阶相关免疫布尔函数的一般计数公式。
关键词 布尔函数 相关免疫 容斥原理 流密码学 平衡矩阵
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两类图同构的充分必要条件 被引量:7
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作者 刘桂真 禹继国 谢力同 《山东大学学报(理学版)》 CAS CSCD 北大核心 2003年第3期1-3,9,共4页
给出了两类图同构的充分必要条件 。
关键词 子图 同构 重构
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不确定图上的kNN查询处理 被引量:7
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作者 张应龙 李翠平 +1 位作者 陈红 杜凌霞 《计算机研究与发展》 EI CSCD 北大核心 2011年第10期1850-1858,共9页
在现实中的许多领域产生大量不确定的图结构的数据,例如分子化合物、蛋白质交互网络等.同时现实中有很多应用例如推荐系统中的推荐过滤、欺诈检测和社会网络的链接预测等,需要查询给定节点的k个最相似节点,针对这一问题,提出了用基于Sim... 在现实中的许多领域产生大量不确定的图结构的数据,例如分子化合物、蛋白质交互网络等.同时现实中有很多应用例如推荐系统中的推荐过滤、欺诈检测和社会网络的链接预测等,需要查询给定节点的k个最相似节点,针对这一问题,提出了用基于SimRank度量的方法来求解.由于图的动态演变和不确定性导致用现有的SimRank计算方法求k个最近邻的代价昂贵,因此提出一个有效算法,在保证一定准确性的前提下,通过引入路径阈值,算法只需考虑查询点的邻居区域无需考虑整个图从而达到明显的剪枝效果,该方法在确定图和不确定图上都可以适用.在此基础上为了进一步提高效率,算法在不确定图上引入采样技术.最后从理论、实验说明验证了算法的高效性和有效性. 展开更多
关键词 不确定图 可能世界 SIMRANK KNN 子图
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Study on Microsatellite Distribution in Complete Genomes of Tobacco Vein Clearing Virus 被引量:7
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作者 杨纪青 《Agricultural Science & Technology》 CAS 2010年第7期132-135,共4页
MATLAB software and optimal complete subgraph algorithm were used to extract and reveal the microsatellite distribution features in the complete genomes of the tobacco vein clearing virus (NC-003 378.1) from the NCB... MATLAB software and optimal complete subgraph algorithm were used to extract and reveal the microsatellite distribution features in the complete genomes of the tobacco vein clearing virus (NC-003 378.1) from the NCBI database.The results showed that the repetitions number and their location of the N-base group has been extracted and displayed.The largest repetitions of N-base group in the complete genomes of the tobacco vein clearing virus was decreased as the exponential function with the increasing of N.The method used in this study could be applied to the extraction and revealing of the microsatellite distribution features in the complete genomes of other viruses,thereby provided a basis for the research of the structure and the law of function,inheritance and variation by the using of the microsatellite distribution features. 展开更多
关键词 Tobacco vein clearing virus Complete genomes Microsatellite distribution Means of genetic algorithms Optimal complete subgraph algorithm
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图的1-因子、f-因子和(g,f)-因子 被引量:4
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作者 汪长平 纪昌明 《数学物理学报(A辑)》 CSCD 北大核心 1999年第1期85-88,共4页
设G是一个图且有一个1-因子F,g和f是定义在V(G)上的非负整数值函数且对每个X∈V(G)有g(X)<f(X)≤dG(x),且f(v(G))为偶数.(i)若对每个xy∈F有f(x)=f(y)且G-{x,y}有一个(g,f)-因子,则G有一个(g,f)-因子;(ii)若对每... 设G是一个图且有一个1-因子F,g和f是定义在V(G)上的非负整数值函数且对每个X∈V(G)有g(X)<f(X)≤dG(x),且f(v(G))为偶数.(i)若对每个xy∈F有f(x)=f(y)且G-{x,y}有一个(g,f)-因子,则G有一个(g,f)-因子;(ii)若对每个xy∈F有f(X)=f(y)且G-{X,y}有f-因子,则G有f-因子. 展开更多
关键词 子图 1-因子 F-因子 (G F)-因子 有限无向图
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与任意图2-正交的(g,f)-因子分解 被引量:5
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作者 周思中 薛秀谦 《华中师范大学学报(自然科学版)》 CAS CSCD 北大核心 2003年第1期17-20,共4页
设G是一个图,用V(G)和E(G)表示它的顶点集和边集,并设g(x)和f(x)是定义在V(G)上的两个整数值函数,且对每个x∈V(G),有4≤g(x)≤f(x),则图G的一个支撑子图F称为G的一个(g,f)-因子,如果对每个x∈V(G),有g(x)≤dF(x)≤f(x).图G的(g,f)-因... 设G是一个图,用V(G)和E(G)表示它的顶点集和边集,并设g(x)和f(x)是定义在V(G)上的两个整数值函数,且对每个x∈V(G),有4≤g(x)≤f(x),则图G的一个支撑子图F称为G的一个(g,f)-因子,如果对每个x∈V(G),有g(x)≤dF(x)≤f(x).图G的(g,f)-因子分解是指E(G)能划分成边不交的(g,f)-因子,设F=F1,F2,…,Fm和H分别是图G的因子分解和子图,若对所有1≤i≤m有|E(H)∩E(Fi)|=2,则称F和H2-正交.本文证明:若G是一个(mg+m-1,mf-m+1)-图,H是G中任一有2m条边的子图,则G有一个(g,f)-因子分解与H2-正交. 展开更多
关键词 子图 (G F)-因子分解 2-正交因子分解 简单图 整数值函数 图论
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Redesign of the gStore system 被引量:3
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作者 Li ZENG Lei ZOU 《Frontiers of Computer Science》 SCIE EI CSCD 2018年第4期623-641,共19页
gStore is an open-source native Resource Description Framework (RDF) triple store that answers SPARQL queries by subgraph matching over RDF graphs. However, there are some deficiencies in the original system design,... gStore is an open-source native Resource Description Framework (RDF) triple store that answers SPARQL queries by subgraph matching over RDF graphs. However, there are some deficiencies in the original system design, such as answering simple queries (including one-triple pattern queries). To improve the efficiency of the system, we reconsider the system design in this paper. Specifically, we propose a new query plan generation module that generates different query plans according to the structures of query graphs. Furthermore, we re-design our vertex encoding strategy to achieve more pruning power and a new multi-join algorithm to speed up the subgraph matching process. Extensive experiments on synthetic and real RDF datasets show that our method outperforms the state-of-the-art algorithms significantly. 展开更多
关键词 graph database subgraph matching RDF management SPARQL query
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基于小波变换和子图的图像配准方法 被引量:5
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作者 孙鑫 谢元旦 任地成 《计算机工程与设计》 CSCD 北大核心 2010年第21期4653-4656,共4页
为了能够快速精确的对图像进行配准,提出了一种基于小波变换的图像配准方法。该方法对基准图像和待配准图像进行小波分解,并利用小波多分辨率分析的优势,采用由粗到精的搜索策略,减少搜索空间,提高配准精度。同时引入子图的概念,用子图... 为了能够快速精确的对图像进行配准,提出了一种基于小波变换的图像配准方法。该方法对基准图像和待配准图像进行小波分解,并利用小波多分辨率分析的优势,采用由粗到精的搜索策略,减少搜索空间,提高配准精度。同时引入子图的概念,用子图代替原图作配准来降低搜索的数据量,通过高效搜索的策略和并行的计算思想来提高运算速度。实验结果表明了该方法有较好的效果,具有较高的应用价值。 展开更多
关键词 图像配准 小波变换 子图 多分辨率分析 并行计算
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Subgraph Matching Using Graph Neural Network 被引量:2
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作者 GnanaJothi Raja Baskararaja MeenaRani Sundaramoorthy Manickavasagam 《Journal of Intelligent Learning Systems and Applications》 2012年第4期274-278,共5页
Subgraph matching problem is identifying a target subgraph in a graph. Graph neural network (GNN) is an artificial neural network model which is capable of processing general types of graph structured data. A graph ma... Subgraph matching problem is identifying a target subgraph in a graph. Graph neural network (GNN) is an artificial neural network model which is capable of processing general types of graph structured data. A graph may contain many subgraphs isomorphic to a given target graph. In this paper GNN is modeled to identify a subgraph that matches the target graph along with its characteristics. The simulation results show that GNN is capable of identifying a target sub-graph in a graph. 展开更多
关键词 subgraph Matching GRAPH NEURAL NETWORK Backpropagation RECURRENT NEURAL NETWORK FEEDFORWARD NEURAL NETWORK
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Extracting Semantic Subgraphs to Capture the Real Meanings of Ontology Elements 被引量:2
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作者 汪鹏 徐宝文 周毓明 《Tsinghua Science and Technology》 SCIE EI CAS 2010年第6期724-733,共10页
An element may have heterogeneous semantic interpretations in different ontologies. Therefore, understanding the real local meanings of elements is very useful for ontology operations such as querying and reasoning, w... An element may have heterogeneous semantic interpretations in different ontologies. Therefore, understanding the real local meanings of elements is very useful for ontology operations such as querying and reasoning, which are the foundations for many applications including semantic searching, ontology matching, and linked data analysis. However, since different ontologies have different preferences to describe their elements, obtaining the semantic context of an element is an open problem. A semantic subgraph was proposed to capture the real meanings of ontology elements. To extract the semantic subgraphs, a hybrid ontology graph is used to represent the semantic relations between elements. An extracting algorithm based on an electrical circuit model is then used with new conductivity calculation rules to improve the quality of the semantic subgraphs. The evaluation results show that the semantic subgraphs properly capture the local meanings of elements. Ontology matching based on semantic subgraphs also demonstrates that the semantic subgraph is a promising technique for ontology applications. 展开更多
关键词 ONTOLOGY ontology graph semantic subgraph ontology matching
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Inductive Relation Prediction by Disentangled Subgraph Structure
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作者 Guiduo Duan Rui Guo +2 位作者 Wenlong Luo Guangchun Luo Tianxi Huang 《Tsinghua Science and Technology》 SCIE EI CAS CSCD 2024年第5期1566-1579,共14页
Currently,most existing inductive relation prediction approaches are based on subgraph structures,with subgraph features extracted using graph neural networks to predict relations.However,subgraphs may contain disconn... Currently,most existing inductive relation prediction approaches are based on subgraph structures,with subgraph features extracted using graph neural networks to predict relations.However,subgraphs may contain disconnected regions,which usually represent different semantic ranges.Because not all semantic information about the regions is helpful in relation prediction,we propose a relation prediction model based on a disentangled subgraph structure and implement a feature updating approach based on relevant semantic aggregation.To indirectly achieve the disentangled subgraph structure from a semantic perspective,the mapping of entity features into different semantic spaces and the aggregation of related semantics on each semantic space are updated.The disentangled model can focus on features having higher semantic relevance in the prediction,thus addressing a problem with existing approaches,which ignore the semantic differences in different subgraph structures.Furthermore,using a gated recurrent neural network,this model enhances the features of entities by sorting them by distance and extracting the path information in the subgraphs.Experimentally,it is shown that when there are numerous disconnected regions in the subgraph,our model outperforms existing mainstream models in terms of both Area Under the Curve-Precision-Recall(AUC-PR)and Hits@10.Experiments prove that semantic differences in the knowledge graph can be effectively distinguished and verify the effectiveness of this method. 展开更多
关键词 disentangled subgraph structure knowledge graph completion Gated Recurrent Unit(GRU) feature updating
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基于时间约束子图抽取的时序知识图谱问答
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作者 刘洋 刘爽 赵泽菲 《大连民族大学学报》 CAS 2024年第3期240-247,共8页
针对时序知识图谱的问答的相关研究较少,并且大多拘泥于语义或者时间信息的匹配,缺乏对时间约束信息利用的问题,提出一种基于时间约束子图抽取的时序知识图谱问答方法。首先通过时间范围信息修剪子图,然后利用修剪后的子图和时间信息进... 针对时序知识图谱的问答的相关研究较少,并且大多拘泥于语义或者时间信息的匹配,缺乏对时间约束信息利用的问题,提出一种基于时间约束子图抽取的时序知识图谱问答方法。首先通过时间范围信息修剪子图,然后利用修剪后的子图和时间信息进行答案推理得到最终答案。实验结果表明:本文方法相较于基线模型在回答复杂类型以及时间类型问题时有较大提升。 展开更多
关键词 时序知识图谱 问答 子图 时间约束
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Social Robot Detection Method with Improved Graph Neural Networks
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作者 Zhenhua Yu Liangxue Bai +1 位作者 Ou Ye Xuya Cong 《Computers, Materials & Continua》 SCIE EI 2024年第2期1773-1795,共23页
Social robot accounts controlled by artificial intelligence or humans are active in social networks,bringing negative impacts to network security and social life.Existing social robot detection methods based on graph ... Social robot accounts controlled by artificial intelligence or humans are active in social networks,bringing negative impacts to network security and social life.Existing social robot detection methods based on graph neural networks suffer from the problem of many social network nodes and complex relationships,which makes it difficult to accurately describe the difference between the topological relations of nodes,resulting in low detection accuracy of social robots.This paper proposes a social robot detection method with the use of an improved neural network.First,social relationship subgraphs are constructed by leveraging the user’s social network to disentangle intricate social relationships effectively.Then,a linear modulated graph attention residual network model is devised to extract the node and network topology features of the social relation subgraph,thereby generating comprehensive social relation subgraph features,and the feature-wise linear modulation module of the model can better learn the differences between the nodes.Next,user text content and behavioral gene sequences are extracted to construct social behavioral features combined with the social relationship subgraph features.Finally,social robots can be more accurately identified by combining user behavioral and relationship features.By carrying out experimental studies based on the publicly available datasets TwiBot-20 and Cresci-15,the suggested method’s detection accuracies can achieve 86.73%and 97.86%,respectively.Compared with the existing mainstream approaches,the accuracy of the proposed method is 2.2%and 1.35%higher on the two datasets.The results show that the method proposed in this paper can effectively detect social robots and maintain a healthy ecological environment of social networks. 展开更多
关键词 Social robot detection social relationship subgraph graph attention network feature linear modulation behavioral gene sequences
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A matching algorithm between precursory 3D process model and 2D working procedure drawing based on subgraph isomorphism 被引量:4
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作者 HUANG Rui ZHANG ShuSheng +1 位作者 FAN HaiTao TAO Jun 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1826-1832,共7页
To meet the urgent requirement of enterprises for three-dimensional (3D) process models, an approach based on subgraph isomorphism is proposed to solve the matching problem between precursory 3D process model and 2D w... To meet the urgent requirement of enterprises for three-dimensional (3D) process models, an approach based on subgraph isomorphism is proposed to solve the matching problem between precursory 3D process model and 2D working procedure drawings. First, the projection drawings of the precursory 3D process model are obtained, then the primitives are extracted and the attributed adjacency graph (AAG) is constructed. Finally, by taking the 2D working procedure drawing as the AAG, and the projection drawing as the whole AAG, the matching problem between precursory 3D process model and 2D working procedure drawings is translated into the problem of subgraph isomorphism. To raise the matching efficiency, the AAG is partitioned, and the vertexes of the graph are classified effectively using the vertex’s attributes. Experimental results show that this method is able to support exact match and the matching efficiency can meet the requirement of practical applications. 展开更多
关键词 subgraph isomorphism process model three-dimensional model reconstruction working procedure drawing
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计算通信网络可靠性的分解技术 被引量:4
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作者 沈元隆 《系统工程学报》 CSCD 1996年第3期47-53,共7页
本文应用分离节点的概念将图分解成两个子图,使通信网络端对可靠性的成功函数简化为两个子网络的可靠性成功子函数,并且进一步导出由子网络不交化表示的原网络的不交化表达式,最后得到通信网络更简便更紧凑的端对可靠性表达式,此简... 本文应用分离节点的概念将图分解成两个子图,使通信网络端对可靠性的成功函数简化为两个子网络的可靠性成功子函数,并且进一步导出由子网络不交化表示的原网络的不交化表达式,最后得到通信网络更简便更紧凑的端对可靠性表达式,此简化方法适用于任意系统可靠性的计算. 展开更多
关键词 通信网 可靠性 分解技术
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基于可控制性度量的图神经网络门级硬件木马检测方法
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作者 张洋 刘畅 李少青 《计算机工程》 CAS CSCD 北大核心 2024年第7期164-173,共10页
随着全球化的不断深入,第三方知识产权(IP)核应用越来越广泛。随着硬件木马攻击技术逐渐成熟,使得在芯片设计阶段植入硬件木马成为可能。因此,在芯片设计过程中面临IP核被植入木马的严重威胁,现有研究所提的硬件木马检测方法具有依赖黄... 随着全球化的不断深入,第三方知识产权(IP)核应用越来越广泛。随着硬件木马攻击技术逐渐成熟,使得在芯片设计阶段植入硬件木马成为可能。因此,在芯片设计过程中面临IP核被植入木马的严重威胁,现有研究所提的硬件木马检测方法具有依赖黄金参考电路、需要完备的测试向量、大量的样本进行学习等特征。面向IP核的硬件木马检测需求,提出一种基于可控制性度量的图神经网络检测方法。该方法以门级网表作为输入,首先以可控制性值为指导,得到可疑的门节点,用于缩小搜索范围;然后利用可疑门节点生成对应的子图,利用图卷积神经网络从子图中提取特征,实现对子图的分类和检测,最终识别硬件木马。实验结果表明,该方法无须测试激励和黄金模型,利用硬件木马的隐蔽特性与结构特征相结合的方法提升硬件木马的检测准确率,平均真阳率为100%,假阳率为0.75%,在保证较高真阳率的同时可有效降低假阳率,达到较好的检测效果。 展开更多
关键词 知识产权核 硬件木马 可控制性度量 子图 图卷积神经网络
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