基于用户浏览行为相似度的HTTP-Get Flood检测方法

基于页面请求的DDOS攻击比传统的海量报文攻击更具杀伤性且检测困难。传统的检测方法包括：特征检测,利用隐马尔科夫模型分析Web页面访问行为。相比明文解析与数学估计,提出了分析用户浏览行为相似性界定HTTP-GetFlood攻击,将用户浏览页面切换与浏览时间的比值表示用户浏览行为,不同用户利用这个表达式计算的浏览行为值很难相等。DDOS攻击爆发时,肉机行为高度一致,导致浏览行为值重复率偏高,当高于一定阀值时判断遭受DDOS攻击。     

Synthesis, characterization of CeO2@SiO2 nanoparticles and their oxide CMP behavior

SiO₂ ultrafine spheres are prepared by sol-gel method using tetraethylorthosilicate and ammonia as raw materials. CeO₂-coated SiO₂ (CeO₂@SiO₂) composite nanoparticles are also synthesized through chemical precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS) and dynamic light scattering (DLS) are used to characterize the CeO₂@SiO₂ composite particles. Silicon wafer covered by thermal oxide film is polished by CeO₂@SiO₂ composite abrasives, and the polishing behavior of novel composite abrasives is characterized by atomic force microscope (AFM). The results indicate that the phases of the as-prepared CeO₂@SiO₂ composite particles are composed of cubic fluorite CeO₂ and amorphous SiO₂. CeO₂@SiO₂ composite particles have excellent spherical morphologies and uniform particle size of 150-200 nm. The particle size of CeO₂ as shell is about 10 nm. After coating, the chemical state of SiO₂ is changed due to the formation of Si-O-Ce bond. The root-mean-square (RMS) roughness within 10 × 10 μm² area of thermal oxide film after polished by CeO₂@SiO₂ composite abrasives is 0.428 nm, and material removal rate can reach 454.6 nm/min.     

在线无人监考防作弊新技术探索

为解决教育资源分布不均衡等问题,发展现代网络教育已经成为全球趋势。无人监考是网络教育体系中重要环节之一。为了确保真学真考,本文针对现阶段远程教育中存在的替学替考、假体攻击、夹带抄袭等作弊行为,探讨了活体人脸检测、跨年代人脸识别、夹带行为检测等安全环节的创新方法。上述新技术有助于提高无人监考的安全性,确保远程网络教育落实到人,推动网络教育建设和发展。     

Beyond the privacy paradox: The moderating effect of online privacy concerns on online service use behavior

In the digital information era, dealing with privacy issues is problematic in related research since online activities have become an inevitable trend. Following the privacy paradox, which occurs when online services are increasingly accepted or used despite raising the level of privacy concerns of individuals, there is no need to alleviate individual privacy concerns regarding online services. Accordingly, this study aims to empirically analyze the effect of online privacy concerns, when interacting with individual innovativeness, on individual online service use behavior. For the empirical analysis, a Heckman two-step analysis is performed using South Korean data from the 2019 Korea Media Panel Survey conducted by the Korea Information Society Development Institute. The results provide evidence in contradiction of the privacy paradox. Specifically, the main findings of this study are as follows. First, use of online services and privacy concerns are not a contradictory phenomenon both in principle and behavior but can act as a negative influence or constraint. Second, individuals with high levels of innovativeness actively use online services owing to differences in their acceptance and use of innovation. Third, as online activities become more common, privacy concerns are likely to affect the level of online service use by interacting with other personality traits. As a result, privacy concerns are more likely to act as an influencing variable that moderates the degree or intensity of an individual's use of an online service rather than an independent variable for the use of an online service. The impact of privacy concerns of individuals on the use of online services identified in this study suggests there is a need for an adequate governing mechanism for privacy protection to realize service provision through e-government.     

基于Kippo蜜罐的SSH暴力破解行为分析

SSH是相对于传统协议而言安全可靠的远程服务协议,然而现今针对于SSH的暴力破解攻击已经严重威胁了其安全性.为了研究SSH暴力破解攻击行为特征,提高系统和服务的安全性,采取了不同于传统网络防护的被动防御策略,搭建了基于Kippo蜜罐的主动防御系统,并基于此,利用Kippo蜜罐的日志记录,对攻击者及其攻击行为特征进行了多方面的详细分析,从而提出了SSH服务的安全建议与加固措施,在一定程度上增强了针对SSH暴力破解攻击的防御能力,提高了安全性.     

氢对TA16钛合金性能影响研究

研究氢对TA16钛合金显微组织、氢脆行为和应力腐蚀行为的影响,以及TA16钛合金在8.5 MPa高温碱性水中的吸氢性能。结果表明,氢在TA16钛合金中形成面心立方的δ相氢化物TiHx(x=1~2)。在室温条件下,TA16钛合金氢脆敏感性随着合金中的氢含量的增加而增大;在8.5 MPa高温碱性水中,TA16钛合金的应力腐蚀敏感性随着合金中氢含量的增加而增大,但合金中氢的体积浓度小于350 mL/m3时,合金的应力腐蚀敏感指数小于0.2。在8.5 MPa高温碱性水中,TA16钛合金的吸氢量随着浸泡时间的增加而增大,浸泡13 000 h后,TA16钛合金的吸氢体积浓度小于50 mL/m3,合金表面形成的由TiO、TiO2和Ti2O3组成的致密氧化膜。     

一种新型钛合金半固态锻造后的断裂行为研究

以新型钛合金Ti14为对象,对比研究常规和半固态锻造合金经不同时间热暴露后的室温拉伸性能,探讨热暴露后的断裂行为及其断裂机制。结果表明,半固态锻造试样热暴露后的强度均明显高于常规锻造试样,而塑性略低于常规锻造试样。常规锻造试样宏观断口三要素清晰可见,断口由细小的韧窝组成,韧窝密度较大;半固态锻造试样纤维区模糊,剪切唇区较大,断口为韧窝和解理的混合型断口,并伴随少量二次裂纹的出现。析出相的尺寸、形态、分布的差异是导致两种锻造态合金热暴露后断裂机制改变的主要原因。     

导引头目标干扰识别与抗干扰

为提高空战中复杂干扰环境下导弹的作战效能,提出一种新的导引头对目标干扰进行识别及抗干扰的方法一基于目标行为模式识别的抗干扰方法,并给出了导引头抗干扰技术方案。最后,分别仿真验证了该方法应用于雷达导引头和红外导引头抗干扰的有效性。     

In对Sn9Zn钎料润湿性能的影响

为了提高Sn9Zn共晶钎料的钎焊性能,通过合金化的方法添加了少量元素In,制备了Sn9Zn-xIn钎料。从钎料合金的熔化特性、润湿特性、界面显微结构和母材粗糙度这四个方面评价了不同In含量对Sn9Zn钎料润湿性能的影响。试验结果表明:少量元素In的添加可以降低钎料的熔点;随着In含量的增加,钎料的润湿力增大,润湿时间缩短,润湿性有明显提高;In含量增加,润湿界面层中Cu5Zn8化合物层厚度增加;对母材表面进行毛化处理,通过改变母材表面的微观几何结构,增大钎料与母材的相对接触面积,从而改善钎料的润湿性能。     

基于关联规则的网络行为分析

网络用户访问网站的过程中,产生了大量的用户浏览网页的相关记录,隐含着用户在上网过程中的行为习惯。但其中潜在的用户信息难以发现。因此,急需有效的方法提取这些数据中的信息,数据挖掘应用而生。其中,关联规则技术是应用广泛的技术之一。文中利用Apriori算法对Web结构数据进行关联规则挖掘,所得到的规则反映出页面之间的链接关系。分析挖掘结果可得到用户访问的行为规律,为相关网站的安全性和优化改进提供有效的决策依据。