共查询到19条相似文献,搜索用时 578 毫秒
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研究蠕虫病毒的传播模型是为了更好地揭示蠕虫传播的规律,预测蠕虫爆发的规模。由于对影响蠕虫传播的因素考虑得不够周详,现有的传播模型还不能很好地模拟蠕虫的传播。针对网络蠕虫的具体传播过程,提出一种模型将网络环境变化和用户免疫过程对蠕虫传播的影响考虑进来,定义了新的感染率函数和免疫率函数,提出了蠕虫传播的动态模型。仿真实验表明,该模型能够较好地预测蠕虫的传播,具有一定的有效性。 相似文献
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由于良性蠕虫可以主动免疫主机,因此使用良性蠕虫来对抗蠕虫传播正成为一种新的应急响应技术.提出了混合的结构化良性蠕虫,设计了它的工作机制以及部署情况.基于传染病模型原理,用数学模型刻画了混合的结构化良性蠕虫对抗蠕虫的传播过程.最后,对于该模型进行了仿真试验.通过仿真结果,总结了影响混合的结构化良性蠕虫对抗蠕虫传播的四个因素:探针探测和探针的蠕虫检测的响应时间,探针的蠕虫检测率和探测率.混合的结构化良性蠕虫对抗蠕虫的传播模型可以使得人们更好地理解良性蠕虫对抗蠕虫的效果. 相似文献
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为了更好地刻画良性蠕虫的传播过程,采用了离散时间模型。在离散时间下,考虑恶性蠕虫和良性蠕虫传播对网络的影响,对混合型良性蠕虫的传播过程进行分析和数学建模,通过仿真验证传播模型,并引入泰勒公式对关键参数进行分析比较。理论分析和仿真实验表明,在混合型良性蠕虫释放时间和网络性能一定的条件下,存在一个临界值使得切换时间最佳,而网络敏感度足够小时,不同的切换时间对感染类主机数量的变化几乎没有影响。 相似文献
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双因素模型考虑了人为对抗因素和蠕虫传播对路由造成的冲击,较SI模型、SIS模型和KM模型更能符合蠕虫传播的实际情况。但它不能反映蠕虫传播后期的特性,同时模型没有考虑大规模系统升级程序和自动补丁程序这一重要的对抗因素对蠕虫传播的影响。针对双因素模型的不足,对其进行了改进,提出了Update-Factor模型,经仿真结果与实际监测结果比较,模型克服了双因素模型的不足,更符合蠕虫传播的实际情况。 相似文献
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基于Two-Factor传播模型提出了一种新的QSIRV传播模型,该模型更合理地考虑了被免疫主机的失效性。通过仿真得出,QSIRV模型较Two-Factor模型能够更好地描述蠕虫的传播规律以及传播过程中网络流量和蠕虫流量之间的相互影响,尤其是对免疫后的主机数目变化的仿真更是符合实际情况,同时考虑了已隔离、免疫及被感染主机的数量的影响以及人们对蠕虫传播的警惕性的提高。对QSIRV模型进行了进一步的改进。仿真结果验证,改进后的模型可以更快地遏制蠕虫传播。 相似文献
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针对混合高斯背景模型计算量大、存在阴影和鬼影的不足,提出一种基于混合高斯模型的改进前景检测算法。通过分析背景的稳定性来选择连续或隔帧更新方式对背景模型中的参数进行更新,提高算法的运算速度。在背景更新方面,让更新率与权值相关联从而使更新率随权值改变并且对目标移动后显露的背景像素给予更大的更新率,提高背景的稳定性并解决鬼影现象及前景与背景转化的问题。对检测出的目标,用适应性更高的RGB颜色空间畸变模型进行阴影检测和消除,并进行高斯金字塔滤波和形态学滤波处理,以得到更好的前景目标。实验结果表明,该方法能提高算法的计算效率且准确地分割前景目标。 相似文献
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鉴于被动型蠕虫对网络的安全构成了威胁,考虑网络异质性和一次搜索允许的跳数,提出一个带有补充率和移除率的新动力学模型,推导出决定被动型蠕虫能否传播的阈值--基本再生数,分析了无蠕虫平衡点和正平衡点的稳定性问题。最后通过数值模拟验证了理论的正确性,并对参数敏感性进行了分析。研究结果发现,当基本再生数大于1时,跳数的增加不但加快被动型蠕虫的传播,而且使感染节点的数量也增加;当基本再生数小于1时,跳数的增加使感染节点的数量迅速减少,最终被动型蠕虫灭绝。 相似文献
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研究网络安全问题,网络蠕虫是当前网络安全的重要威胁。网络蠕虫传播途径多样化、隐蔽性强、感染速度快等特点。蠕虫模型以简单传染病模型进行传播,无法准确描述网络蠕虫复杂变化特点,网络蠕虫检测正确率比较低。为了提高网络蠕虫检测正确率,提出一种改进的网络蠕虫传播模型。在网络蠕虫传播模型引入动态隔离策略,有效切断网络蠕虫传播途径,采用自适应的动态感染率和恢复率,降低网络蠕虫造成的不利影响。仿真结果表明,相对于经典网络蠕虫传播模型,改进模型有效地加低了网络蠕虫的传播速度,提高网络蠕虫检测正确率和整个网络安全性,为网络蠕虫传播研究提供重要指导。 相似文献
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提出一种新的网络蠕虫传播模型,并基于生物免疫原理提出了成熟良性蠕虫、记忆良性蠕虫和疫苗良性蠕虫新概念,建立了新的主机状态转移关系,运用系统动力学理论和方法,建立了一种新的网络蠕虫免疫模型,它能够从定性和定量两方面分析和预测网络蠕虫免疫过程,并能够深入刻画恶性蠕虫和良性蠕虫交互过程中的网络特性,为动态防治网络蠕虫提供了新的理论依据。模拟实验结果表明,引入的三种良性蠕虫是动态防御恶性网络蠕虫传播的重要因素。 相似文献
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Machine learning techniques are widely used in many fields. One of the applications of machine learning in the field of information security is classification of a computer behavior into malicious and benign. Antiviruses consisting of signature-based methods are helpless against new (unknown) computer worms. This paper focuses on the feasibility of accurately detecting unknown worm activity in individual computers while minimizing the required set of features collected from the monitored computer. A comprehensive experiment for testing the feasibility of detecting unknown computer worms, employing several computer configurations, background applications, and user activity, was performed. During the experiments 323 computer features were monitored by an agent that was developed. Four feature selection methods were used to reduce the number of features and four learning algorithms were applied on the resulting feature subsets. The evaluation results suggest that by using classification algorithms applied on only 20 features the mean detection accuracy exceeded 90%, and for specific unknown worms accuracy reached above 99%, while maintaining a low level of false positive rate. 相似文献
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This paper presents the results of survey of the availability and use of computers in a preschool sample in Chile, and compares them with similar results of primary and secondary schools. Results show that although preschools have relatively low access to computers and teachers have relatively low ICT competencies, they declare similar ICT related obstacles and impacts compared to their colleagues in secondary schools. Also, results show that preschool students seem to use computers in the classroom more frequently than their peers in primary and secondary schools and that the activities they implement are focused on developing key curriculum related areas implementing tasks that can be associated to the exercising of key competencies and skills. This specialised use of computers in preschools, which is much more focused than the activities with computers reported by teachers in higher levels, could be explained by the relative low variety of educational software available in these preschools, the availability of the computers in the classroom rather than in labs; the special type of teaching and learning activities implemented at this age level and/or due to the relative lack of teachers' ICT competencies. On the one hand, these results highlight the need for further research, and on the other, it constitutes an interesting lesson for policy designer that tend to advocate for considering computers as “multipurpose” technologies that should be used across subjects, levels and teaching strategies. In this case, computers seem to play a very specific and concrete role in preschools classrooms that, eventually, contributes to improve students' outcomes, which highlights the potential of considering the use of computers, software and other technologies to improve specific subject areas at particular levels while designing ICT in education policies for this age group. 相似文献
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目前已有一些蠕虫检测系统利用蠕虫传播特性进行检测,误报率高,不能对大范围网络进行检测。为此,首先对蠕虫传播模型进行了分析和优化,提出了新蠕虫分布式传播模型。针对该模型提出了分布式蠕虫检测技术,亦即采用基于规则的检测方法监控网络蠕虫,控制台管理和协调多个检测端的工作。实验结果表明,该方法能够很好地预警蠕虫的传播行为并进行监控和报警,具有高检测率和低误报率。 相似文献