A Binary Decision Diagram based on-line testing of digital VLSI circuits for feedback bridging faults

Classical manufacturing test verifies that a circuit is fault free during fabrication, however, cannot detect any fault that occurs after deployment or during operation. As complexity of integration rises, frequency of such failures is increasing for which on-line testing (OLT) is becoming an essential part in design for testability. In majority of the works on OLT, single stuck at fault model is considered. However in modern integration technology, single stuck at fault model can capture only a small fraction of real defects and as a remedy, advanced fault models such as bridging faults, transition faults, delay faults, etc. are now being considered. In this paper we concentrate on bridging faults for OLT. The reported works on OLT using bridging fault model have considered non-feedback faults only. The basic idea is, as feedback bridging faults may cause oscillations, detecting them on-line using logic testing is difficult. However, not all feedback bridging faults create oscillations and even if some does, there are test patterns for which the fault effect is manifested logically. In this paper it is shown that the number of such cases is not insignificant and discarding them impacts OLT in terms of fault coverage and detection latency. The present work aims at developing an OLT scheme for bridging faults including the feedback bridging faults also, that can be detected using logic test patterns. The proposed scheme is based on Binary Decision Diagrams, which enables it to handle fairly large circuits. Results on ISCAS 89 benchmarks illustrate that consideration of feedback bridging faults along with non-feedback ones improves fault coverage, however, increase in area overhead is marginal, compared to schemes only involving non-feedback faults.     

下一代自动测试系统体系结构研究进展

以下一代自动测试系统为研究对象,介绍了它的研制背景,分析了自动测试系统体系结构的开放性要求。简述了关键单元的筛选标准和发展过程,指出了基于关键单元建立的开放式体系结构的意义。研究了硬件结构组成及测试程序集的开发和运行的技术模型,说明了敏捷快速全球作战保障演示验证项目和关键单元的标准制定情况,为我军发展下一代自动测试系统提供参考。     

基于CP-ABE的云计算改进属性加密安全访问控制策略设计

针对云计算存储中心由于数据和访问控制的安全性无法得到有效保障,从而可能造成用户存储的敏感数据被盗取的问题,现有的解决方法往往通过加密数据密钥,并通过对数据加密来解决安全性问题,但这些方法没有对访问控制的整个过程进行全面的定义和描述,同时仍然具有较大的时空开销。为此,在对CP-ABE(eiphertext-policy attribute-based encryption)进行深入分析的基础上提出了一种基于改进属性加密访问控制模型,然后对CP-ABE进行改进,并对公钥和主密钥的生成、数据所有者加密文件、访问用户解密文件以及用户权限的全面管理过程均进行了详尽的定义和描述,从而设计了一种通用的安全访问机制。在仿真工具Ubuntu中进行实验,结果表明文中方法能有效地实现云计算环境下的安全访问控制,与其它方法相比,具有计算和存储开销低优点,具有较大的优越性。     

基于多线程的AES-ECB改进设计与性能分析

为了满足高速即时通信对密码运算的性能要求,在研究AES-ECB典型设计的基础上,提出了一种基于多线程技术的AES-ECB改进设计方案。通过对算法中间迭代过程进行分割,并将其例化为多个子线程,改进了算法运行流程,实现了子线程间的“类流水”操作。实例性能分析表明,相比于单线程,多线程性能提高了约0.46至4.27倍;当线程数为12时,算法处理性能最低为520Mbps,适用于对加解密速度要求高的应用场合。     

基于混沌理论和改进径向基函数神经网络的网络舆情预测方法

网络舆情发展趋势具有混沌系统的特征, 提出一种基于EMPSO-RBF神经网络的方法对网络舆情的发展趋势进行预测. 首先根据Lyapunov指数证明网络舆情具备混沌的特征, 然后对网络舆情时间序列数据进行相空间重构, 最后采用EMPSO-RBF方法进行预测, 并和其他模型进行对比试验, 实验结果表明EMPSO-RBF方法具有较高精确度.     

A Low-Memory Algorithm for Point Counting on Picard Curves

Combining the ideas of Bauer, Teske and Weng, [1] and Gaudry, Schost [3], we give a low memory algorithm for computing the number of points on the Jacobian of a Picard curve. It is efficient enough to handle Picard curves over finite prime fields , where p is a prime with 58 bits. We present an example where the Jacobian has a prime group order of size 2¹⁷⁴     

Bounds for visual cryptography schemes

In this paper, we investigate the best pixel expansion of various models of visual cryptography schemes. In this regard, we consider visual cryptography schemes introduced by Tzeng and Hu (2002) [13]. In such a model, only minimal qualified sets can recover the secret image and the recovered secret image can be darker or lighter than the background. Blundo et al. (2006) [4] introduced a lower bound for the best pixel expansion of this scheme in terms of minimal qualified sets. We present another lower bound for the best pixel expansion of the scheme. As a corollary, we introduce a lower bound, based on an induced matching of hypergraph of qualified sets, for the best pixel expansion of the aforementioned model and the traditional model of visual cryptography scheme realized by basis matrices. Finally, we study access structures based on graphs and we present an upper bound for the smallest pixel expansion in terms of strong chromatic index.     

一种新的基于椭圆曲线密码体制的 Ad hoc组密钥管理方案

在安全的组通信中,组密钥管理是最关键的问题.论文首先分析了组密钥管理的现状和存在的问题,然后基于椭圆曲线密码体制,针对Ad hoc网络提出了一种安全有效的分布式组密钥管理方案,并对其正确性和安全性进行了证明,由椭圆曲线离散对数困难问题保证协议的安全.针对Ad hoc网络节点随时加入或退出组的特点,提出了有效的组密钥更新方案,实现了组密钥的前向保密与后向保密.与其他组密钥管理方案相比,本方案更加注重组成员的公平性,没有固定的成员结构,并且还具有轮数少、存储开销、通信开销小等特点,适合于在Ad hoc网络环境中使用.     

一种可信远程证明通信机制的设计与实现

现有远程证明实现方法从度量静态二进制代码、平台配置文件到安全策略监控来衡量目标平台的可信性,但这些方法灵活性和可行性不强,对可信平台客户端配置要求较高且尚未成熟。文中利用IMA机制改进了传统TCG远程证明方案,增加了度量的灵活性,减小了可信平台客户端压力;同时加入了密钥托管机制,解决了可信计算密钥托管和恢复问题。     

诱惑态下相位差分量子密钥分发效率分析

讨论基于微弱相干脉冲的相位差分量子密钥分发系统,综合分析系统的安全性问题,给出了密钥生成效率表达式.分析诱惑态对相位差分量子密钥分发系统安全性的影响,并给出了结合诱惑态后的密钥生成效率表达式.结果表明,结合诱惑态的相位差分量子密钥分发过程不再受到分光子攻击和序列攻击的威胁,其密钥分发效率与Hoi-Kwong等人提出的诱惑态的表述结果一致.实验数据显示,结合诱惑态后的相位差分系统,其安全传输距离得到了进一步提高,量子密钥分发效率提高了约1个数量级.