大数据环境下的云计算网络安全入侵检测模型仿真

在大数据云计算环境下,由于信息交互的开放性和自组织性,导致云计算网络容易受到攻击,研究大数据环境下的云计算网络安全入侵检测模型,提高网络安全防御能力。提出一种基于人工免疫的网络安全态势分析的网络安全入侵检测模型。构建网络安全入侵的信号模型和安全态势分析模型,通过模拟人体免疫系统,进行网络映射,采用双线性Hough变换进行时频变换,实现算法改进。仿真结果表明,采用该模型能有效提高对云计算网络入侵的检测性能,对攻击特征的识别能力较高。     

结合信息熵的多Agent网络安全审计模型

针对目前网络安全审计中存在网络日志数据分析的智能性不高及安全审计模型采用的集中式结构负担重等缺点,设计一种新的多Agent网络安全审计模型,并在该模型中引入一种改进的基于信息熵的攻击检测算法.在实际运行环境中,通过对DDoS等攻击行为进行模拟和成功检测,证明该改进模型能够有效审计部分网络入侵,提高安全审计效率和日志数据...     

基于多维信息熵值的DDoS攻击检测方法

针对互联网中日益严重的分布式拒绝服务攻击行为,提出了一种基于多维信息熵值的DDoS攻击检测方法.首先根据DDoS攻击的特点,采用条件熵及相异熵构建具有良好区分度的多维攻击检测向量,在此基础上采用滑动窗口的多维无参数CUSUM算法放大正常流量与攻击流量的差异来实现DDoS攻击的检测.通过实际网络攻击流量及合成攻击流量测试表明:文中提出的算法能够检测到LLS_ DDoS数据集及合成数据集中的全部攻击,算法对于DDoS攻击的响应速度快,能够应用于高速骨干网络中.     

基于OpenFlow的SDN网络环境下DDoS攻击检测系统

为了在软件定义网络(SDN)环境中有效解决分布式拒绝服务攻击(DDoS)的问题,提出了一种主被动结合、统计流表特征的DDoS攻击检测方法.利用SDN网络架构在部署DDoS攻击检测系统方面灵活和多维度的特点,通过控制器从大量的网络设备中早期发现受害主机,并有针对性的进行攻击检测.首先通过packet_in消息被动统计作为预判,进而下发监控流表进一步细粒度统计特征,并利用XGBoost算法构造异常检测分类器进行分类攻击.最后在OpenDayLight控制器中实现了上述DDoS攻击检测系统,并在Mininet网络中进行了评估验证.结果表明,这种检测方法可以高效定位出遭受DDoS攻击的网络设备并检测出受害主机,XGBoost算法应用在此场景中可以在保证检测率的同时发挥其处理效率高的特性,适用于此系统.     

软件定义网络DDoS联合检测系统

分布式拒绝服务(distributed denial-of-service,DDoS)攻击已成为网络安全的最大威胁之一。传统的对抗方式如入侵检测、流量过滤和多重验证等,受限于静态的网络架构,存在明显的缺陷。软件定义网络(software-defined networking,SDN)作为一种新型动态网络体系,其数控分离、集中控制与动态可编程等特性颠覆了现有的网络架构,为对抗DDoS攻击提供了新的思路。现有基于SDN的DDoS防护方案处于研究的起步阶段,且存在较多问题。针对现有方案中检测周期过小将导致系统开销大的问题,该文提出由触发检测和深度检测相结合的DDoS联合检测方案,将低开销、粗粒度的触发检测算法与高精度、细粒度的深度检测算法相结合,在保障高检测精度的前提下降低了系统的复杂度;同时,在Mininet平台上实现了基于SDN的DDoS攻击检测系统,设计实验对系统进行测试和评估。实验结果表明:该系统具有开销小、检测准确率高的特性,实用价值较强。     

数据挖掘技术在网络入侵检测中的应用

论述了入侵检测系统的基本概念，针对目前入侵检测系统中存在的问题，提出了一个基于数据挖掘技术的自适应入侵检测系统模型。介绍了该系统模型的基本思想，阐述其结构及主要功能，着重分析了该系统的数据挖掘和检测过程。利用数据挖掘技术自动地从大量数据中提取重要的特征和新的模式，生成有意叉的规则并建立检测模型，实现对分布式拒绝服务攻击DDoS（Distrbute Denial of Service）入侵的检测方法。     

基于网络连接统计的分布式拒绝服务攻击检测

分析了分布式拒绝服务(D istributed D en ial of Serv ice,DDoS)攻击原理及其攻击特征,提出了一种基于网络连接统计的DDoS攻击检测方法。该方法利用DDoS攻击的固有特性,从网络连接数据的统计分析中探寻系统正常行为的特征分布,建立DDoS攻击检测模型。通过模拟攻击实验验证了检测方法的可行性。实验结果表明:该方法能快速有效地实现对DDoS攻击的检测,并对其他网络安全检测研究具有一定的指导意义。     

基于网络异常流量判断DoS/DDoS攻击的检测算法

为了对泛洪DoS/DDoS(Denial of Service/Distributed Denial of Service)攻击做出准确判断,在对泛洪DoS/DDoS攻击发生时网络流量变化特性进行分析的基础上,给出一种基于网络异常流量判断泛洪DoS/DDoS攻击的检测算法.该算法通过对流量大小和波动趋势的判断,对泛洪DoS/DDoS攻击的发生进行检测.实验结果表明,在不失一般性的基础上,判断泛洪DoS/DDoS攻击的成功率为100%.     

基于应用层的DDoS攻击模型与安全防御策略研究

为了针对目前具有较强隐蔽性的多向量应用层DDoS(Distributed denial of service)攻击方式,对应用层攻击的模型深入分析,提出了应用层发生的DoS(Denial of Service)攻击防御模型.通过构建并弹性获得吸收攻击所需的带宽容量和过滤攻击流量的网络架构以及基于云计算的虚拟防火墙安全策略,减少数据中心受到DDoS攻击的可能性.使用该攻击防御模型能够更好提高数据中心对应用层DDoS攻击的防御能力,改善网络环境.经过验证该模型能够显著提升网络系统的安全性能.     

基于应用层的DDoS攻击模型与安全防御策略研究

为了针对目前具有较强隐蔽性的多向量应用层DDoS(Distributed denial of service)攻击方式,对应用层攻击的模型深入分析,提出了应用层发生的DoS(Denial of Service)攻击防御模型.通过构建并弹性获得吸收攻击所需的带宽容量和过滤攻击流量的网络架构以及基于云计算的虚拟防火墙安全策略,减少数据中心受到DDoS攻击的可能性.使用该攻击防御模型能够更好提高数据中心对应用层DDoS攻击的防御能力,改善网络环境.经过验证该模型能够显著提升网络系统的安全性能.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.