剖析缓冲区溢出攻击

本文从程序设计语言的特征、程序编写、数据结构以及程序执行控制等多个角度对缓冲区溢出漏洞攻击的原理进行深入剖析,最后提出了遏制利用缓冲区溢出漏洞进行攻击的一些措施。     

Windows7操作系统关键内存防攻击研究

GS Stack Protection、SafeSEH、Heap Protection、DEP、ASLR技术是Windows 7操作系统内存保护机制的关键技术,这五种技术对缓解缓冲区溢出攻击起到显著作用.文章以对Windows 7的内存保护机制的原理分析为基础,测试了Windows 7环境下绕过这些保护机制的可能性;最后对Windows 7内存保护机制抵御缓冲区溢出攻击的整体效果进行了分析,指出Windows7仍然不能完全抵御缓冲区溢出攻击,并讨论了更全面提高系统安全性的改进方案.     

Huffman算法的改进及其在图像压缩中的应用

本文改进了Huffman编码算法,主要是针对Huffman编码生成Huffman树构造中的排序方法的改进,提出一种基于"堆排序"的新方法。采用堆排序找到最小值实现Huffman编码,经过这种改进的Huffman编码方法对内存读写的次数大为减少,从而提高了响应速度。使得Huffman编码效率有所提高。通过对JPEG的Huffman压缩算法的分析以及采用4个JPG文件对改进的和传统的Huffman算法进行了仿真实验,对比分析表明改进算法的性能无论是压缩比率还是压缩时间方面都比经典的Huffman算法性能有所提高。     

基于带权策略的蠕虫智能扩散

运用带权策略树建模方法,给出一种蠕虫智能扩散模型,描述蠕虫智能扩散的本质特征和执行过程,解决一般蠕虫不能感知目标环境及其改变,从而不能选择有效的扩散策略问题。针对该模型提出基于堆遍历的蠕虫智能扩散算法。分析和仿真实验结果表明,该模型能够灵活描述和实现较为普遍的扩散,具有较高的扩散效率。     

最优堆排序算法

本文讨论了堆的若干性质,提出对堆排序算法的改进,改进后的堆排序算法是一个最优排序算法,在最坏情况下需要ｎｌｏｇｎ＋ｎａ３（ｎ）＋Ｏ（ｎ）次元素比较和ｎｌｏｎ＋Ｏ（ｎ）次元素移动。     

基于堆排序的PQ+CBWFQ路由器排队调度算法

研究具有QoS特征、易于实现的排队算法一直是优化带宽的重要手段，也是提高宽带IP网络性能的主要途径。文章提出基于堆排序的PQ＋CBWFQ网络路由器排队调度算法进行具体实现，并给出低成本的硬件实现方案，对未来的高性能路由器设计具有重要的参考价值。     

A simple generational real-time garbage collection scheme

This paper presents and empirically evaluates a generational real-time garbage collection scheme, which is based on combining Baker’s real-time scheme with a simple generational scheme by Andrew W. Appel. Real World Computing Partnership. Khayri A. M. Ali, Ph.D.: He currently works as Dean of the Faculty of Computer Science at October University for Modern Sciences and Arts, Egypt. He received his B. Sc. (1970) in Electronics, his M. Sc. (1977) in Automatic Control, both from Egypt. He received his Ph.D. in Computer Systems from the Royal Institute of Technology, Stockholm, in 1984. His research interests are in developing parallel and distributed logic, functional, object-oriented, and constraints programming systems.     

Effect of geotextile ageing and geomembrane surface roughness on the geomembrane-geotextile interfaces for heap leaching applications

A series of large scale direct shear experiments is used to investigate the effect of the geomembrane (GMB) surface roughness, geotextile (GTX) properties, and GTX ageing, on the GMB-GTX interface shear behaviour. Interfaces involving smooth, coextruded textured, and structured surface GMBs underlying four different nonwoven needle-punched staple fibres (GTXs) with mass per unit areas between 200 and 2400 g/m², and a geocomposite drain (GCD) are examined at normal stresses between 250 and 1000 kPa. The results showed that the interlocking between the GMB and GTX increased with increasing the GMB asperity height and/or decreasing the mass per unit area of the GTX. For the interfaces that involved GTXs preaged prior to the shear box experiments for up to 2 years at 85 °C, it was found that the 2400 g/m² heat bonded two-layered GTX exhibited internal shear failure at low shear displacements. However, all the highly aged single layered GTXs showed an increase in the peak interface friction angles with the increase in their ageing. For these single layered GTX, the results suggest that assessing the interface friction angles using unaged GTXs for the stability analysis is conservative as long as the GTX remains intact in the field.     

堆浸雾化布液条件实验研究

布液是堆浸浸出工艺中一个重要环节之一。本文介绍了一种新的布液方法——雾化布液。用铀矿石模拟矿堆，通过堆浸雾化布液条件实验，得出使用该布液法能得到较高的浸出液铀平均浓度及较高的浸出率，能缩短浸出时间，提高经济效益，从而验证了雾化布液的优越性。为堆浸矿山采用雾化布液提供参考依据。     

紫金山金矿提金工艺研究与探讨

介绍了紫金山金矿采用堆浸、全泥氰化提金试验的原则流程和结果，对堆浸－全泥氰化联合提金试验和原则流程合理性进行了初步分析和探讨，并对该矿提金工艺提出了看法，可供现有提金选矿厂改造和新建提金破厂设计参考。