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通过对网络病毒感染下振荡攻击数据混淆分离,实现对网络病毒攻击数据的特征定位和提取,有效检测网络病毒数据。传统方法中对网络病毒感染下的振荡攻击数据的检测和分离方法使用行为特征分析和卡尔曼滤波方法,算法受到数据振荡和线性特征干扰的影响,检测性能不好。提出一种基于双线性本征波匹配的振荡攻击数据混淆分离算法,构建网络病毒感染振动攻击模型,提取攻击数据的信号模型特征,根据调解病毒样本序列的线性化程度,确定双线性本征陷波器频率参数和带宽参数,实现对信号的滤波,进而实现混淆分离算法的改进。仿真结果表明,该算法设计的滤波器进行振荡攻击数据的混淆分离,具有较好的抗噪能力和干扰抑制能力,对网络病毒攻击数据的混淆分离均方根误差较小,对病毒感染下的振荡攻击信号的检测性能较高,展示了其优越性能。 相似文献
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云系统中的漂移数据作为大量冗余数据的一种,对其有效及时的删除能保证云存储系统的稳定与运行。传统的云系统漂移数据删除技术采用全文件静态分块策略,由于操作粒度较小,对漂移数据的删除率不高。提出一种基于垂直分层布隆过滤的云系统漂移数据删除算法,设计基于客户端/服务器的云存储系统漂移数据删除机制体系构架,采用布隆过滤技术进行数据源端处理,引入热度垂直索引热度来衡量数据块边界偏移所造成用户的访问集中热点损失,文件根据内容划分成可变长度的数据块,进行垂直分层,得到备份集中数据对象的粒度,采用奇异值分解的方式对漂移数据序列的细节信号展示,根据矩阵奇异值分解矢量的唯一性,避免一些数据块边界偏移造成的误删和漏删。仿真实验表明采用该算法进行云系统的漂移数据删除,性能较好,执行效率和精度优越于传统算法。 相似文献
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提出了一种新的基于排队论的DoS攻防绩效评估方法. 针对不同种类DoS攻防手段建立了统一的指标体系和绩效计算方法,基于排队论方法分别建立评估模型,对UDP Flood和SYN Flood攻击的绩效进行不包含主观因素的定量评估,分析不同攻击手段和强度的有效性. 针对典型DoS攻防场景,利用网络仿真工具进行模拟,通过实验与模型推导结果对比验证了排队论模型的合理性,并阐述了此方法在不同类型DoS攻防手段中的应用. 相似文献
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大型数据库中,数据种类和数量较大,其中的强冗余数据干扰了需要查询的数据,导致数据关联属性弱化,查询数据过程中,严重干扰数据库查询的精度。提出一种基于弱匹配区域划分模型的数据库分区查询方法,在数据库中融入弱匹配区域的概念,依据数据融合属性特征,对数据属性融合差异较大的区域进行分割,获取数据弱匹配区域,在该区域中运算最大数据属性弱匹配度的相似性并进行聚类分析,实现弱匹配区域数据属性特征的过滤,利用弱匹配区域划分模型下数据库修补技术对数据进行实时关联修补,通过弱匹配区域的数据库查询优化方法,删除失效数据,缩小数据库中数据的冗余性,实现数据库中数据查询的优化。实验结果说明,采用所提方法进行弱匹配区域划分模型下数据库库查询,具有较高的查询效率和准确率。 相似文献
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在拒绝服务攻击（DoS）基础上产生的分布式拒绝服务攻击（DDos）已成为当今Internet面临的主要威胁之一。在分析攻击原理的基础上,提出了一种Linux系统下基于正则表达式的DDoS防御方法。 相似文献
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将随机森林融合支持向量机(RF-SVM)模型引入个人信用评估问题中,利用随机森林的特征选择算法,对实验样本进行属性特征选择,将得到的结果作为输入变量构建模型,以获得更高的预测精度。通过对大量SVM分类模型研究,发现传统SVM模型中无法有效筛选预测指标。通过对实验样本实证研究,并验证该模型的预测结果可信度,将其与单独的全变量SVM模型结果比对,结果证明,该方法能获得较好的预测效果。 相似文献
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《科技通报》2017,(1)
有效防御病毒对工控系统的入侵是目前工控安全研究的难点问题。为了提高工控系统入侵检测的准确率,本文设计提出了一种主成分分析(PCA)与PSO-SVM相结合的工控入侵检测方法。针对工业控制系统网络数据高维的特性,该方法利用PCA对采集的网络入侵数据进行数据降维与特征提取,支持向量机(SVM)入侵检测的性能主要取决于核函数参数取值的优劣,采用粒子群算法(PSO)对支持向量机参数进行优化,以获得最优的SVM工业控制系统入侵检测模型。采用密西西比州立大学关键基础设施保护中心最新提出的工控标准数据集进行仿真实验,结果表明该算法在攻击检测与攻击类型识别方面均有较高的查准率,提高了工业控制系统的安全性能。 相似文献
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《科技通报》2015,(8)
对云计算系统中的漂移数据中心分类区的准确确定,可以提高云计算系统的扩展能力和缓存能力。传统方法采用线性差分智能群识别方法实现中心分类区的确定,导致漂移数据的群辨识效果不好。提出一种基于粒子群聚类的云计算系统中数据中心分类区的确定算法模型,并进行仿真实现。构建云计算系统网络激励传播机制,实现资源负载均衡,把云计算系统的存储数据结构定义为一个四叉树,构建云计算网格环境下空间资源调度框架体系,进行云计算系统的漂移数据特征提取,使得资源负载均衡达到最优值,实现算法改进。实验得出,模型对云计算系统的漂移数据中心分类区确定准确,数据融合精度较高,聚类性好,云计算系统的扩展指数提高13%,缓存执行能力提高20.5%,展示较好的性能。 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献