针对LBlock的代数攻击的研究

本文主要介绍了运用代数分析方法分析LBlock。采用MiniSAT作为攻击过程中的求解工具，对LBlock加密进行实际攻击，可以在90 min内恢复7轮加密的所有密钥。     

基于学习的GSAT算法

在GSAT算法的基础上，引进学习的概念，设计了一种新的SAT求解算法，用若干DIMAC的测试实例进行了仿真实验研究，比较了基于学习的GSAT算法与著名的Random Walk GSAT算法，结果表明两种算法对于随机SAT的实例比较有效，但对于Real-World SAT的实例性能较差。     

Experimental Study of Discriminative Adaptive Training and MLLR for Automatic Pronunciation Evaluation

A stronger canonical model was developed to improve the performance of automatic pronunciation evaluations.Three different strategies were investigated with speaker adaptive training to normalize variations among speakers,minimum phone error training to identify easily confused phones and maximum likelihood linear regression(MLLR) adaptation to compensate for accent variations between native and non-native speakers.The three schemes were combined to improve the correlation coefficient between machine scores and human scores from 0.651 to 0.679 on the sentence level and from 0.788 to 0.822 on the speaker level.     

The leading correlation of the winter Aleutian Low with surface air temperature during the subsequent summer over the Arctic and its possible mechanism

The variations of surface air temperature(SAT)over the Arctic are closely related to global climate change.Based on reanalysis datasets and a newly defined Aleutian Low intensity index,we found a good correlation between intensity of winter Aleutian Low and the SAT over the Arctic during the subsequent summer.Explanations were given using correlation analysis,composite analysis,and singular value decomposition methods.When intensity of winter Aleutian Low was weaker,sea surface temperature appeared higher in the North Pacific in the subsequent spring and summer,resulting in mean meridional circulation anomalies and 500 hPa geopotential height anomalies in spring and summer.Anomalous upward motion in mid-latitudes and downward motion in high latitudes(Ferrel cell weakening)transported the warmer air to the north from lower layer to the upper layer followed by increases in the SAT over the Arctic.Anomalous downward motion over about 75°N also caused consequent adiabatic warming and contributed to inhibit the heat transportation from surface to upper layer.Negative 500 hPa geopotential height anomalies existed in mid-latitudes and positive anomalies existed in high latitudes.The pattern(low-in-south and high-in-north)benefited from increasing the inflow volume flux of the Bering Strait,which also made the SAT over the Arctic increase.The results of this study reveal the process that the summer SAT over the Arctic was modulated by interannual variability of intensity of winter Aleutian Low.     

Some variants of SAT and their properties

A new model for the well-known problem, the satisfiablility problem of boolean formula (SAT), is introduced. Based on this model, some variants of SAT and their properties are presented. Denote by NP the class of all languages which can be decided by a non-deterministic polynomial Turing machine and by P the class of all languages which can be decided by a deterministic polynomial-time Turing machine. This model also allows us to give another candidate for the natural problems in ((NP-NPC)-P), denoted as NPI, under the assumption P≠NP, where NPC represents NP-complete. It is proven that this candidate is not in NPC under P≠NP. While, it is indeed in NPI under some stronger but reasonable assumption, specifically, under the Exponential-Time Hypothesis (ETH). Thus we can partially solve this long standing important open problem.     

兼顾最优个体的模拟退火分层遗传算法

针对传统分层遗传算法存在"发散"、收敛速度慢和最优解易丢失等缺陷,本文提出了一种改进的分层遗传算法,采用基于模拟退火思想的底层交叉和变异算子,避免底层算法的"发散"、提高收敛速度;设计了一种兼顾最优个体的高层选择算子,防止最优个体丢失。求解SAT问题的比较实验结果表明:求解成功率与收敛速度等算法性能均有较大提升。     

基于CUDA并行平台实现核膜系统求解可满足性问题的研究

膜系统能以空间换时间的方式在多项式时间内求解NP难问题,作为膜系统中的一个新类型,核膜系统不仅包含了不同类型膜系统的特征,而且能提供一种统一性的描述．因此基于核膜系统构建系统模型,并以此求解一个典型的NP难问题：可满足性问题．为了加速对核膜系统的仿真过程,程序将在CUDA并行方式下仿真实现,通过与传统的串行方式比较,使用CUDA能减少95％的仿真时间,这也表明使用CUDA并行方式非常适合仿真核膜系统．     

基于离散Lagrange方法的分布式SAT问题求解

基于对离散Lagrange方法(DLM)的扩充，提出一个分布式SAT求解算法：EDLMSAT。求解过程中，单个Agent的行为由预先定义的EDLM规则所决定，这些局部的行为聚集起来，形成整个系统对问题的求解趋势。设计了一些对3-SAT基准问题的模拟实验，实验结果表明了这个算法良好的求解性能。     

一个求解SAT问题的随机算法

本文中引入了一个求解满足性问题的随机算法。在该算法中,利用CNF公式转换为其对偶式——DNF公式,通过对满足DNF公式的真值赋值数Y作出估计。根据Y与2n比较结果,对CNF公式的可满足性进行估计并对其满足性进行判断。     

一阶逻辑模型生成器的实现

介绍了SAT问题的各种求解方法及一阶逻辑模型生成的两种方法, 在此基础上给出实现一阶逻辑模型生成器FOLMG的各个实现步骤. 并对实现的模型生成器与MACE进行了对比测试与结果分析.