大型差异数据库中入侵路径恢复模型分析

在大型差异数据库中,假设入侵特征存在较大的伪装,将难以形成入侵判断的依据,无法建立入侵路径恢复模型;提出基于敏感性数据挖掘方法的大型差异数据库中入侵路径恢复方法模型;利用主成分分析方法搜索大型差异数据路中的入侵路径,为模型的建立提供准确的数据基础,利用敏感性数据挖掘方法能够检测到入侵路径的特征,从而能够建立准确的入侵路径模型;实验结果表明,利用改进方法进行大型差异数据库中入侵路径恢复,能够提高恢复的准确性,从而保证大型差异数据库的安全。     

湖北省城镇垃圾处理政策研究

在对垃圾处理现状进行系统的调查研究的基础上,作者提出了湖北省城镇垃圾处理的合理改革与相应措施．     

Engineering TCP transmission and retransmission mechanisms for wireless networks

Transmission Control Protocol (TCP) provides mechanisms for reliable data communications. Although it works well in wired networks, it fails to offer satisfactory performance in lossy and wireless environments. And in the multi-hop wireless infrastructure, packet delivery suffers high cumulative loss rate if traveling over multiple wireless hops. The Selective acknowledgment (SACK) is one header option that might be used to combat segment corruptions in air channels. In this paper, an alternative set of flow control mechanisms is proposed to handle high packet loss rate in a wireless medium. Using a measurement-based mechanism, sustainable segment delivery is achievable through a novel size-reduction method. Multiple segment retransmission mechanisms are introduced to reduce successive timeout events. One single byte loss is sufficient to waste all other bytes in a file received at a destination. That is, a good TCP flow control mechanism should provide a high successful file transmission completion rate, and this is set as our design goal. Through thorough simulations, our proposed multi-segment retransmission designs perform with higher successful file transfer rate and fewer timeout events than NewReno and SACK under a wide range of packet loss probabilities.     

Windows删除文件的取证分析

随着计算机犯罪案件成指数增长,基于Windows的取证分析技术日益普遍,而犯罪嫌疑人掩盖证据最通常的做法就是将有用证据删除,因此,对这些删除文件进行取证分析显得更为重要.删除文件中很可能包含和案件相关的重要证据,如用户数据文件、声音文件等,文章结合数据恢复技术和Windows删除机制特点,提出了一种对Windows删除文件的取证分析方法,能够获取更多的用户信息,为重构案情,了解用户行为提供了更有效的依据.     

一种分布式防火墙规则冲突的检测算法

为解决分布式防火墙中因规则冲突而导致策略异常问题,提出了一种基于XML的DFW策略异常的发现算法;该算法在分布式防火墙系统中,对于处在不同防火墙策略中的每条规则,设计一棵单根结点的树来表示分布式防火墙策略,即策略树(Policy Tree),然后通过集合全部的策略树,完成防火墙之间策略异常的发现过程;通过对算法的模拟运行,发现该算法在速度性能和可伸缩性方面较其他算法有很大的改进。     

A low-jitter low-power monolithically integrated optical receiver for SDH STM-16

A high-scale integrated optical receiver including a preamplifier, a limiting amplifier, a clock and data recovery (CDR) block, and a 1:4 demultiplexer (DEMUX) has been realized in a 0.25 μm CMOS technology. Using the loop parameter optimization method and the low-jitter circuit design technique, the rms and peak-to-peak jitter of the recovered 625 MHz clock are 9.4 and 46.3 ps, respectively, which meet the jitter specifications stipulated in ITU-T recommendation G.958. In response to 2.5 Gb/s PRBS input da...     

基于小波能双重自恢复的音频数字水印算法

本文设计了一种在音频信息中加入双重图像作为数字水印,这些水印经过多种攻击能相互自恢复的算法。此算法实现了将双重图像作为数字水印嵌入到WAV音频载体中的过程,在实现过程中通过对载体进行3层小波分解,将数字水印的信息嵌入到第三层小波解的低频区,即CA3中,并对双重数字水印分别设置密钥,建立起两者间稳定的映射关系,能较好地以完成自恢复的功能。     

A secure collaboration service for dynamic virtual organizations

Nowadays, various promising paradigms of distributed computing over the Internet, such as Grids, P2P and Clouds, have emerged for resource sharing and collaboration. To enable resources sharing and collaboration across different domains in an open computing environment, virtual organizations (VOs) often need to be established dynamically. However, the dynamic and autonomous characteristics of participating domains pose great challenges to the security of virtual organizations. In this paper, we propose a secure collaboration service, called PEACE-VO, for dynamic virtual organizations management. The federation approach based on role mapping has extensively been used to build virtual organizations over multiple domains. However, there is a serious issue of potential policy conflicts with this approach, which brings a security threat to the participating domains. To address this issue, we first depict concepts of implicit conflicts and explicit conflicts that may exist in virtual organization collaboration policies. Then, we propose a fully distributed algorithm to detect potential policy conflicts. With this algorithm participating domains do not have to disclose their full local privacy policies, and is able to withhold malicious internal attacks. Finally, we present the system architecture of PEACE-VO and design two protocols for VO management and authorization. PEACE-VO services and protocols have successfully been implemented in the CROWN test bed. Comprehensive experimental study demonstrates that our approach is scalable and efficient.     

云存储及其安全性研究

云存储是在云计算概念上延伸和发展出来的一个新的概念,旨在对外提供数据存储和业务访问服务。在分析云存储基本概念、结构和特点的基础上,对云存储的安全性进行了研究和分析。云存储的安全性问题是制约云存储发展的首要问题,针对非法访问、数据泄漏、数据存取故障等安全问题提出了挑战-应答式的云存储身份认证、基于用户与密钥关联的加密存储、数据恢复等多项安全解决方案,能够避免传统身份认证口令被攻击的风险,使用户可以选择加密算法使用密钥进行数据加密,以及透明地为用户提供快速且与存取并行的数据恢复。     

一种多功能网络监控与防御平台设计与实现

本文提出了一种多功能网络监控与防御系统。文中根据网络自身的结构,从骨干层、汇聚层、接入层三个层次分析,采用三层设计模式,它们相互独立又相互协作,共同构成高性能、多层次、多功能综合解决方案。形成深度防御体系,最大限度地保护企业和组织的网络安全。