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余倾斜挠类和包络余模 被引量:1
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作者 李园 姚海楼 《北京工业大学学报》 CAS CSCD 北大核心 2021年第12期1388-1394,共7页
为了研究余代数中余倾斜挠类和包络余模之间的关系,首先引入余模的(预)包络和finendo的定义并研究它们的性质.然后,引入极大余倾斜余模和包络余模,并证明余倾斜挠类和极大余倾斜余模之间存在一个双射.最后,得到了在余代数上当余倾斜挠... 为了研究余代数中余倾斜挠类和包络余模之间的关系,首先引入余模的(预)包络和finendo的定义并研究它们的性质.然后,引入极大余倾斜余模和包络余模,并证明余倾斜挠类和极大余倾斜余模之间存在一个双射.最后,得到了在余代数上当余倾斜挠类是包络类时,它可以由包络余模唯一表示. 展开更多
关键词 包络 finendo 包络类 极大余倾斜余模 余倾斜挠 包络余模
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开放环境下自适应聚类优化包络的相机来源取证 被引量:1
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作者 王波 王悦 +1 位作者 王伟 侯嘉尧 《电子学报》 EI CAS CSCD 北大核心 2022年第8期1840-1850,共11页
针对相机来源取证中的开放环境问题,本文提出一种自适应聚类优化包络的相机来源取证方法,解决了现有方法在训练相机模型数量少的恶劣情况下检测精度低的问题.首先,通过手肘法得到每一类相机数据的聚类个数,并以该聚类数为参照进行k-mean... 针对相机来源取证中的开放环境问题,本文提出一种自适应聚类优化包络的相机来源取证方法,解决了现有方法在训练相机模型数量少的恶劣情况下检测精度低的问题.首先,通过手肘法得到每一类相机数据的聚类个数,并以该聚类数为参照进行k-means聚类;然后将得到的相机模型子类数据分别进行支持向量数据描述以刻画其子包络,并根据所属相机模型类别将子包络合成一个更具细节特征的特征包络;最后通过判决法则将来自未知相机模型的图像排除,并将判断为已知来源的图像分类溯源,进而实现开放环境下的相机来源鉴别.实验结果表明,在Dresden和SOCRatES两个公开数据集上,本文提出的算法具有更优的鲁棒性和扩展性,与已有方法相比,在KACC,UACC和OACC三个评估指标和时间复杂度上均表现出更优越的性能. 展开更多
关键词 开放环境 数字图像取证 相机来源鉴别 手肘法 包络优化
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A novel internet traffic identification approach using wavelet packet decomposition and neural network 被引量:6
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作者 谭骏 陈兴蜀 +1 位作者 杜敏 朱锴 《Journal of Central South University》 SCIE EI CAS 2012年第8期2218-2230,共13页
Internet traffic classification plays an important role in network management, and many approaches have been proposed to classify different kinds of internet traffics. A novel approach was proposed to classify network... Internet traffic classification plays an important role in network management, and many approaches have been proposed to classify different kinds of internet traffics. A novel approach was proposed to classify network applications by optimized back-propagation (BP) neural network. Particle swarm optimization (PSO) algorithm was used to optimize the BP neural network. And in order to increase the identification performance, wavelet packet decomposition (WPD) was used to extract several hidden features from the time-frequency information of network traffic. The experimental results show that the average classification accuracy of various network applications can reach 97%. Moreover, this approach optimized by BP neural network takes 50% of the training time compared with the traditional neural network. 展开更多
关键词 neural network particle swarm optimization statistical characteristic traffic identification wavelet packet decomposition
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Towards Efficient Security Policy Lookup on ManyCore Network Processing Platforms 被引量:1
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作者 WANG Xiang QI Yaxuan +2 位作者 WANG Kai XUE Yibo LI Jun 《China Communications》 SCIE CSCD 2015年第8期146-160,共15页
Modem network security devices employ packet classification and pattern matching algorithms to inspect packets. Due to the complexity and heterogeneity of different search data structures, it is difficult for existing... Modem network security devices employ packet classification and pattern matching algorithms to inspect packets. Due to the complexity and heterogeneity of different search data structures, it is difficult for existing algorithms to leverage modern hardware platforms to achieve high performance. This paper presents a Structural Compression (SC) method that optimizes the data structures of both algorithms. It reviews both algorithms under the model of search space decomposition, and homogenizes their search data structures. This approach not only guarantees deterministic lookup speed but also optimizes the data structure for efficient implementation oi1 many-core platforms. The performance evaluation reveals that the homogeneous data structure achieves 10Gbps line-rate 64byte packet classification throughput and multi-Gbps deep inspection speed. 展开更多
关键词 packet classification patternmatching ALGORITHMS data structures
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The V1 region of gp120 is preferentially selected during SIV/HIV transmission and is indispensable for envelope function and virus infection
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作者 Yanpeng Li Ulf Dittmer +3 位作者 Yan Wang Jiping Song Binlian Sun Rongge Yang 《Virologica Sinica》 SCIE CAS CSCD 2016年第3期207-218,共12页
A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted vi... A transmission bottleneck occurs during each human immunodeficiency virus(HIV) transmission event, which allows only a few viruses to establish new infection. However, the genetic characteristics of the transmitted viruses that are preferentially selected have not been fully elucidated. Here, we analyzed amino acids changes in the envelope protein during simian immunodeficiency virus(SIV)/HIV deep transmission history and current HIV evolution within the last 15–20 years. Our results confirmed that the V1V2 region of gp120 protein, particularly V1, was preferentially selected. A shorter V1 region was preferred during transmission history, while during epidemic, HIV may evolve to an expanded V1 region gradually and thus escape immune recognition. We then constructed different HIV-1 V1 mutants using different HIV-1 subtypes to elucidate the role of the V1 region in envelope function. We found that the V1 region, although highly variable, was indispensable for virus entry and infection, probably because V1 deletion mutants exhibited impaired processing of gp160 into mature gp120 and gp41. Additionally, the V1 region affected Env incorporation. These results indicated that the V1 region played a critical role in HIV transmission and infection. 展开更多
关键词 simian immunodeficiency virus(SIV) human immunodeficiency virus(HIV) transmission selection V1 loop Env function
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Tightness of certain monomials
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作者 CUI WeiDeng 《Science China Mathematics》 SCIE CSCD 2015年第6期1297-1304,共8页
For a quantized enveloping algebra of finite type, one can associate a natural monomial to a dominant weight. We show that these monomials for types A5 and D4 are semitight(i.e., a Z-linear combination of elements in ... For a quantized enveloping algebra of finite type, one can associate a natural monomial to a dominant weight. We show that these monomials for types A5 and D4 are semitight(i.e., a Z-linear combination of elements in the canonical basis) by a direct calculation. 展开更多
关键词 algebra canonical Cartan tight proof bilinear associate irreducible concerned integer
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