DEFIDNET: A framework for optimal allocation of cyberdefenses in Intrusion Detection Networks

Intrusion Detection Networks (IDN) are distributed cyberdefense systems composed of different nodes performing local detection and filtering functions, as well as sharing information with other nodes in the IDN. The security and resilience of such cyberdefense systems are paramount, since an attacker will try to evade them or render them unusable before attacking the end systems. In this paper, we introduce a system model for IDN nodes in terms of their logical components, functions, and communication channels. This allows us to model different IDN node roles (e.g., detectors, filters, aggregators, correlators, etc.) and architectures (e.g., hierarchical, centralized, fully distributed, etc.). We then introduce a threat model that considers adversarial actions executed against particular IDN nodes, and also the propagation of such actions throughout connected nodes. Based on such models, we finally introduce a countermeasure allocation model based on a multi-objective optimization algorithm to obtain optimal allocation strategies that minimize both risk and cost. Our experimental results obtained through simulation with different IDN architectures illustrate the benefit of our framework to design and reconfigure cyberdefense systems optimally.     

一种可替代漂珠的低密度材料

漂珠低密度水泥浆由于密度低、强度高、体系稳定而在油田低压易漏层及低压油气层长封固段固井作业中获得了广泛的应用。但近年来,由于漂珠的产量越来越少,油田低成本要求急需开发代替漂珠的新型减轻材料,以满足配制低密度水泥浆的需求。开发了BCL-10S低密度混合减轻材料,其物化性能与漂珠相当,用它作减轻剂配制的低密度水泥浆性能与用漂珠作减轻剂配制的低密度水泥浆性能相媲美,并已经在长庆油田获得了应用。     

Oleuropein Inhibits LDL Oxidation Induced by Cooking Oil Frying By-products and Platelet Aggregation Induced by Platelet-Activating Factor

Oleuropein, a polyphenolic glucoside, constituent of olive fruit and oil, has been previously shown to exhibit, in vitro, potent properties as a biological antioxidant. In the present paper, two new properties are demonstrated in vitro as well, concerning its vascular protection activity, against the atheromatic lesion formation and its blood antithrombotic effect. Firstly, it was found that the oxidation of low-density lipoproteins (LDL), induced by different quantities of total polar materials (TPM), was inhibited by 10 μ M (final concentration) of oleuropein, revealing approx. 50% protection. Secondly, platelet-rich human plasma aggregation, induced by either the platelet-activating factor or adenosine diphospate or arachidonic acid, was inhibited by oleuropein. The 10 μ M (final concentration) of oleuropein was proven to be the most effective among the tested concentrations against LDL oxidation, while an IC₅₀=0.41 mM was calculated for its inhibitory activity against platelet aggregation induced by 0.7 μ M platelet-activating factor.     

单片机破解的常用方法及应对策略

介绍了单片机内部密码破解的常用方法，重点说明了侵入型攻击／物理攻击方法的详细步骤，最后，从应用角度出发，提出了对付破解的几点建议。     

Binary rewriting and call interception for efficient runtime protection against buffer overflows

Buffer overflow vulnerabilities are one of the most commonly and widely exploited security vulnerabilities in programs. Most existing solutions for avoiding buffer overflows are either inadequate, inefficient or incompatible with existing code. In this paper, we present a novel approach for transparent and efficient runtime protection against buffer overflows. The approach is implemented by two tools: Type Information Extractor and Depositor (TIED) and LibsafePlus. TIED is first used on a binary executable or shared library file to extract type information from the debugging information inserted in the file by the compiler and reinsert it in the file as a data structure available at runtime. LibsafePlus is a shared library that is preloaded when the program is run. LibsafePlus intercepts unsafe C library calls such as strcpy and uses the type information made available by TIED at runtime to determine whether it would be ‘safe’ to carry out the operation. With our simple design we are able to protect most applications with a performance overhead of less than 10%. Copyright © 2006 John Wiley & Sons, Ltd.     

数字水印攻击及对策分析

数字水印技术作为数字媒体版权保护的重要手段越来越引起人们的重视。文章讨论了数字水印的概念、特征,重点介绍了数字水印的鲁棒性及影响数字水印鲁棒性的因素,总结和分析了数字水印主要攻击方式并提出相应的应对措施。     

TNFα-Induced LDL Cholesterol Accumulation Involve Elevated LDLR Cell Surface Levels and SR-B1 Downregulation in Human Arterial Endothelial Cells

Excess lipid droplets are frequently observed in arterial endothelial cells at sites of advanced atherosclerotic plaques. Here, the role of tumor necrosis factor alpha (TNFα) in modulating the low-density lipoprotein (LDL) content in confluent primary human aortic endothelial cells (pHAECs) was investigated. TNFα promoted an up to 2 folds increase in cellular cholesterol, which was resistant to ACAT inhibition. The cholesterol increase was associated with increased ¹²⁵I-LDL surface binding. Using the non-hydrolysable label, Dil, TNFα could induce a massive increase in Dil-LDL by over 200 folds. The elevated intracellular Dil-LDL was blocked with excess unlabeled LDL and PCSK9, but not oxidized LDL (oxLDL), or apolipoprotein (apoE) depletion. Moreover, the TNFα-induced increase of LDL-derived lipids was elevated through lysosome inhibition. Using specific LDLR antibody, the Dil-LDL accumulation was reduced by over 99%. The effects of TNFα included an LDLR cell surface increase of 138%, and very large increases in ICAM-1 total and surface proteins, respectively. In contrast, that of scavenger receptor B1 (SR-B1) was reduced. Additionally, LDLR antibody bound rapidly in TNFα-treated cells by about 30 folds, inducing a migrating shift in the LDLR protein. The effect of TNFα on Dil-LDL accumulation was inhibited by the antioxidant tetramethythiourea (TMTU) dose-dependently, but not by inhibitors against NF-κB, stress kinases, ASK1, JNK, p38, or apoptosis caspases. Grown on Transwell inserts, TNFα did not enhance apical to basolateral LDL cholesterol or Dil release. It is concluded that TNFα promotes LDLR functions through combined increase at the cell surface and SR-B1 downregulation.     

含硅镍低密度钢的温拉伸力学行为及强韧机制

 为了分析硅镍合金化奥氏体基低密度钢在中温环境下的拉伸变形行为,采用Instron电子拉力试验机对Fe-28.64Mn-8.99Al-1.68Si-1.39Ni-1.0C(Mn29Al9Si2Ni,质量分数/%)低密度钢在23~300 ℃下进行了温拉伸试验,研究了该钢的温拉伸力学行为,并采用SEM、TEM和热力学计算对该钢的强韧化机制进行了研究。结果表明,随着应变的增加,温拉伸应力-应变曲线主要包括弹性变形、均匀塑性变形和断裂等几个过程,没有明显的屈服现象。随着温度的提高,该钢的强度逐渐降低,塑性(断后伸长率)先增加后减小再升高,于200 ℃时出现塑性低谷,此时该钢的应力-应变曲线和应变硬化率曲线均具有明显的锯齿状特征,应变硬化率随应变的增加变化不大。而该钢在其他温度下的应力-应变曲线和应变硬化率曲线没有发现明显的“锯齿状”特征,应变硬化率随应变的增加而平缓下降。试验钢在23~300 ℃下的主要强韧化机制为κ-碳化物强化、应变强化、孪生诱发塑性和动态应变时效强化。较低温度下位错可动性较差对孪生诱发的促进作用、镍元素和硅元素对孪生的抑制作用、较高温度下孪生现象的减弱和温度对动态应变时效的促进或抑制作用等使得试验钢在23、100和300 ℃时存在明显的孪生诱发塑性,而在200 ℃时存在明显的动态应变时效强化的主要原因。动态应变时效强化是该钢在200 ℃时出现塑性低谷的主要原因。     

玻璃微珠改性PP和PE-LLD的加工流变行为

采用玻璃微珠改性两种基体性质显著不同的聚烯烃并对玻璃微珠的含量、粒径和复合材料加工方法对材料的加工流变行为进行了研究。结果表明：加工方法、玻璃微珠含量和粒径对聚丙烯/空心玻璃微珠(PP/GB)复合材料的熔体流动速率和转矩流变性能的影响远大于对PE-LLD/GB复合材料的影响，其中玻璃微珠含量的影响较粒径大。研究认为，无机刚性粒子填充改性热塑性聚合物时，加工方法、填料含量、几何特征等对复合材料流变特性是否发生影响，影响的程度等，更重要的是取决于基体树脂的特性。     

填充用开孔聚氨酯硬泡组合料的研制

研制的填充用聚氨酯硬泡组合料，具有料液稳定、流动性好，所制泡沫泡孔均匀、开孔率高、不易收缩等特点。该组合料制得的泡沫性能为：泡沫密度15kg／m^3，开孔率大于98％，流动性大于1．3cm／g，压缩强度大于0．1MPa。