DDoS攻击及其防范策略

比较Dos 与DDos的概念,引入DDos攻击的原理,介绍了DDos攻击的常用工具,提出针对DDos攻击的对策,包括DDos 攻击的监测、防御DDos攻击以及遭受DDos攻击后的处理等,经过小型网站运行经验的验证,文中提出的攻击对策和防范策略是极其有效的.     

Hadoop DDos攻击检测算法分析

针对Hadoop平台可能遭受的DDos攻击,需要对Hadoop DDos攻击的检测算法进行研究需要对常用的SVM、KNN、神经网络、Decision Tree、Naive Bayesian算法进行研究。文章通过搜集主机正常运行时和遭受攻击时的资源使用信息作为数据集,运用上述算法进行分析后发现,SVM对Hadoop DDos攻击检测具有高达91.75%的准确率。实验结果表明,SVM是最适合Hadoop平台DDos攻击检测的算法。     

一种基于分布式的DDos防御体系设计

首先深入分析和评价了目前DDos攻击的防御策略,然后针对它们的不足,提出了一种分布式协同防御的DDos防御体系,该体系将防御节点分布式部署于ISP网络的各个位置,通过统一的管理方式,采用受害端检测,源端防御的策略来实现对DDos攻击的有效防御.     

从南京“1.9”破坏信息系统案看侦办DDos类攻击案件

DDos类网络攻击已经成为互联网上越来越流行的攻击模式,攻击者可以使用攻击软件,操纵肉鸡组成僵尸网络,对任意的互联网对象进行攻击。危害性巨大,但由于DDos攻击源的不确定性和跳转性等特点,给此类案件的侦查取证带来很大困难。本文立足江苏省南京市公安局网警支队侦破的一起DDos类攻击案件,剖析由于先期取证,有效掌握侦查主动权。本文从DDos攻击案件的侦查取证的现状、困难入手,着重阐述该案带给我们侦办此类案件的启示。     

DDoS攻击技术发展研究

综述了DDoS(DistributedDenialofService,分布式拒绝服务)攻击的概念、原理及其发起攻击的体系结构,阐述了DDos攻击技术发展和未来攻击技术的发展趋势,最后给出了防范DDos攻击的策略建议。     

DDoS攻击与检测技术

分布式拒绝服务攻击已经成为网络最大的安全威胁之一,如何有效的防御DDos攻击已经引起了诸多学者的关注,文章阐述了分布式拒绝服务攻击的原理,攻击类型,检测方法和对DDos攻击防御策略。     

基于源目的IP地址对数据库的防范DDos攻击策略

提出了一种基于源目的IP地址对数据库的防范分布式拒绝服务攻击(distributed denial of service attacks,简称DDos)攻击策略.该策略建立正常流量的源目的IP地址对数据库(source and destination IP address database,简称SDIAD),使用扩展的三维Bloom Filter表存储SDIAD,并采用改进的滑动窗口无参数CUSUM(cumulative sum)算法对新的源目的IP地址对进行累积分析,以快速准确地检测出DDos攻击.对于SDIAD的更新,采用延迟更新策略,以确保SDIAD的及时性、准确性和鲁棒性.实验表明,该防范DDos攻击策略主要应用于边缘路由器,无论是靠近攻击源端还是靠近受害者端,都能够有效地检测出DDos攻击,并且有很好的检测准确率.     

DDos攻击检测过程中的特征选取与分析

技术发展带来了便利的同时也带来了安全问题.在DDos攻击的检测上,研究了将深度学习模型应用于DDos攻击检测上的第一阶段,特征选择.使用CICDDos 2019数据集作为研究对象,选择了其中的5种DDos攻击.研究发现皮尔逊相对系数是进行特征选择的一个重要依据,选择出的特征在频率分布等方面体现了不同攻击和非攻击数据的差异性,同时也具备可解释性.     

基于DSP的Shrew DDos攻击检测

文章介绍了一种异于传统DDos的攻击方式Shrew DDos,重点讨论了这种攻击的特点、攻击参数与效果。由于Shrew DDos的隐蔽性,传统的入侵检测系统很难把它和正常的数据流区分开。文章给出了一个基于数字信号处理(Digital Signal Processing,DSP)的检测方案,并对检测算法的复杂性和检测的实时性进行了讨论。     

对DDoS攻击的实现技术的研究

阐述了DDoS攻击的原理与方法,详细介绍了DDos攻击的实现。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

Enhancing a leaf radiative transfer model to estimate concentrations and in vivo specific absorption coefficients of total carotenoids and chlorophylls a and b from single-needle reflectance and transmittance

The relative concentrations of different pigments within a leaf have significant physiological and spectral consequences. Photosynthesis, light use efficiency, mass and energy exchange, and stress response are dependent on relationships among an ensemble of pigments. This ensemble also determines the visible characteristics of a leaf, which can be measured remotely and used to quantify leaf biochemistry and structure. But current remote sensing approaches are limited in their ability to resolve individual pigments. This paper focuses on the incorporation of three pigments—chlorophyll a, chlorophyll b, and total carotenoids—into the LIBERTY leaf radiative transfer model to better understand relationships between leaf biochemical, biophysical, and spectral properties.Pinus ponderosa and Pinus jeffreyi needles were collected from three sites in the California Sierra Nevada. Hemispheric single-leaf visible reflectance and transmittance and concentrations of chlorophylls a and b and total carotenoids of fresh needles were measured. These data were input to the enhanced LIBERTY model to estimate optical and biochemical properties of pine needles. The enhanced model successfully estimated reflectance (RMSE = 0.0255, BIAS = 0.00477, RMS%E = 16.7%), had variable success estimating transmittance (RMSE = 0.0442, BIAS = 0.0294, RMS%E = 181%), and generated very good estimates of carotenoid concentrations (RMSE = 2.48 µg/cm², BIAS = 0.143 µg/cm², RMS%E = 20.4%), good estimates of chlorophyll a concentrations (RMSE = 10.7 µg/cm², BIAS = − 0.992 µg/cm², RMS%E = 21.1%), and fair estimates of chlorophyll b concentrations (RMSE = 7.49 µg/cm², BIAS = − 2.12 µg/cm², RMS%E = 43.7%). Overall root mean squared errors of reflectance, transmittance, and pigment concentration estimates were lower for the three-pigment model than for the single-pigment model. The algorithm to estimate three in vivo specific absorption coefficients is robust, although estimated values are distorted by inconsistencies in model biophysics. The capacity to invert the model from single-leaf reflectance and transmittance was added to the model so it could be coupled with vegetation canopy models to estimate canopy biochemistry from remotely sensed data.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).