Traceable content protection based on chaos and neural networks

In this paper, a media content encryption/decryption algorithm is designed based on a chaos system and neural networks, which generates random sequences with chaos, and encrypts or decrypts media contents with neural networks in a parallel way. In this scheme, different decryption keys can be used to recover the media content into different copies. That is, the decryption operation gets the content containing certain random sequence that can be used as the identification. With respect to this property, the scheme is used for secure content distribution. Taking the audio content for example, it is encrypted by a key at the sender side and decrypted by different keys at the receiver side. The differences between decryption keys lead to different decrypted audio copies. If one customer distributes his copy to other unauthorized customers, the chaotic sequence contained in the copy can tell the illegal customer. The performances, including security, imperceptibility and robustness, are analyzed, and some experimental results are given to show the scheme's practicability.     

多Agent的DDoS源地址追踪方法研究

对数据包标记的各种技术进行了深入研究,分析它们存在的问题,基于上述的研究,提出一种多Agent的追踪方法,以解决传统方法存在的重构需要大量数据包,追踪鲁棒性和实时性差等问题.该方法采用并行分布式的结构,将整个追踪区域分成若干自治网络,在各自治网络内独立采用动态的标记概率等算法,同时设立追踪Agent进行自治区内的追踪,最终将由追踪管理器收集各追踪Agent的部分攻击路径并重构出整个攻击路径.理论分析表明,该方法降低了计算量和误报率,增强了追踪的实时性和准确性等.     

嵌入式疲劳驾驶监测系统的设计与实现

疲劳驾驶是引发恶性交通事故的重要原因之一,驾驶员疲劳监测技术近年来已逐步成为图像处理领域的一个研究热点。基于改进的和提出的新算法,设计了一个嵌入式驾驶员疲劳监测系统。由可见光/近红外摄像头采集视频,首先采用Haar特征的级联分类器从图像中检测出人脸区域,并用钻石搜索法跟踪人脸区域;然后提取一个新的图像差分统计特征,并结合3个准则判断疲劳状态;最后采用全变分模型消除图像中的非均匀光照,以便实现鲁棒的人眼定位和人脸识别。实验测试结果表明,本系统的疲劳状态监测准确率达到95%以上。     

Optimum design of electromagnetic shielding rooms with minimum usage of absorbing materials

In this article, a novel method has been proposed to optimize the electromagnetic shielding rooms. This method is based on using minimum electromagnetic absorbing materials on the inner surface of the rooms. The positions of the absorbing materials are found optimally to produce a “best” performance for the shielding rooms. The ray‐tracing method is used to predict the shielding effectiveness (SE) of the electromagnetic shielding rooms with apertures. The performance of the proposed method is verified by a comprehensive example. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 2010.     

三维图像中边界曲面的抽取与半透明可视化

已有算法在重构及可视化梯度值从高到低变化且包含弱边界的边界曲面时无法分辨弱边界与噪声碎片。针对上述问题,提出边界曲面半透明显示方法。采用半透明显示技术显示边界曲面及附着在其上的小碎片,利用人的智能及知识在观察可视化结果时对小碎片及弱边界进行有效的区分。结果证明,该方法有助于正确理解及完整显示三维图像中梯度值从高到低变化的边界曲面,为进一步的交互式操作去除小碎片提供依据。     

叛逆者追踪方案的密码学分析

对一种叛逆者追踪方案提出安全性分析,指出它存在的安全缺陷有被撤销的叛逆者可以在合法用户的帮助下继续解密新密文及合法用户可以合谋伪造有效的解密密钥。提出伪造攻击方案,并给出方案被攻击的原因。指出方案的一个设计错误,说明该方案在实际操作上是不可行的。     

基于程序分析的分布式应用自动化追踪方法

提出了一种零配置的端到端细粒度追踪的方法-EasyTrace,应用于分布式系统发生性能降级时的问题诊断.传统工具往往存在监测粒度与服务组件源码紧耦合或配置信息复杂、修改代价高等不足,EasyTrace能够做到零配置下性能问题的准确定位.基于开源电子商务系统的实验结果表明,EasyTrace相对传统监测工具对系统造成的扰动很小.     

工程配置的版本分类及产品版本追踪模型

工程配置的进化过程分为配置释放前、释放后和交付三个阶段,处于不同阶段的工程配置通常用不同的库来管理,提出了按工程配置的进化阶段将各库中配置的版本分为设计版本、在线版本和产品版本的版本分类法;探讨了基于该版本分类法的版本管理方法,其中对产品版本的管理作了重点讨论,提出了适应工程管理和技术人员不同需要的版本追踪模型。     

Traceable P2P record exchange: a database-oriented approach

In recent years, peer-to-peer (P2P) technologies are used for flexible and scalable information exchange in the Internet, but there exist problems to be solved for reliable information exchange. It is important to trace how data circulates between peers and how data modifications are performed during the circulation before reaching the destination for enhancing the reliability of exchanged information. However, such lineage tracing is not easy in current P2P networks, since data replications and modifications are performed independently by autonomous peers—this creates a lack of reliability among the records exchanged. In this paper, we propose a framework for traceable record exchange in a P2P network. By managing historical information in distributed peers, we make the modification and exchange histories of records traceable. One of the features of our work is that the database technologies are utilized for realizing the framework. Histories are maintained in a relational database in each peer, and tracing queries are written in the datalog query language and executed in a P2P network by cooperating peers. This paper describes the concept of the framework and overviews the approach to query processing.     

基于光线跟踪的数字影像重建技术

本文讨论了CT模拟中的数字图像重建技术,提出了基于光线跟踪的处理方法,并对分辨率、CT值转换和增强技术进行了探讨,给出了在治疗计划系统中的实现。