Efficient conditional probability theorem and importance sampling-based methods for global reliability sensitivity analysis

Global reliability sensitivity (GRS) analysis can measure the effect of random inputs on failure probability (FP). To efficiently solve GRS, two conditional probability theorem (CPT)-based methods are proposed by combining adaptive Kriging (AK) with importance sampling (IS) (CPT-AK-IS) and combining AK with Meta-IS (CPT-AK-Meta-IS) respectively. Firstly, differentiation approximation and CPT are used to convert the estimation of conditional probability density function (PDF), which is required by the existing Bayes theorem-based methods, into that of a series of probabilities. Secondly, GRS can be directly estimated by the failure samples of IS, while the existing Bayes theorem methods based on IS need to transform the failure samples of IS into those of original PDF. Both the first and second strategies can reduce the computational complexity of solving GRS. Thirdly, by selecting a suitable differentiation interval with a proposed adaptive strategy, the estimation of a series of probabilities can be accurately completed as a byproduct of one IS based simulation for solving FP without additional computational cost. Finally, by introducing AK into IS and Meta-IS, it can reduce the number of evaluating performance function and the size of candidate sample pool simultaneously. These novelties are sufficiently verified by the presented examples.     

双枝模糊集(Ⅲ)

提出双枝模糊集Ｓ的理论,本课题是［Ⅰ,Ⅱ］研究的继续．在单枝模糊集理论（Ｌ．Ａ．ＺａｄｅｈＦｕｚｚｙＳｅｔＴｈｅｏｒｙ）研究中,由于引进λ－截集Ｓλ的概念,便产生了单枝模糊集的并－普通分解定理［３］,交－普通分解定理［４］．［Ⅰ,Ⅱ］提出了双枝模糊集Ｓ,由于引进了λ－截集Ｓλ的概念,便产生了双枝模糊集Ｓ的并－普通分解定理,交－普通分解定理．人们自然提出这样的问题：双枝模糊集可以分解成若干个普通集Ｓλ;双枝模糊集Ｓ是否能分解成若干个模糊集Ｓα？本文的研究说明：双枝模糊集Ｓ可以分解成若干个模糊集Ｓα．（一个单枝模糊集Ａ也可以分解成若干个模糊集Ａα,但是在单枝模糊集理论中没有被人们去研究．）本文给出Ｓ的α－嵌入集Ｓα的概念,提出Ｓ的α－嵌入定理,Ｓ的α－嵌入模糊分解定理．     

双枝模糊集(Ⅱ)

提出双枝模糊集Ｓ的理论,是（Ｉ）研究的继续．提出双枝模糊集Ｓ的并－普通分解定理,交－普通分解定理．这些结论建立了双枝模糊集Ｓ与普通集Ｓλ之间的关系,这些结论为建立双枝模糊推理,双枝模糊控制作了理论准备．结论指出：（１）双枝模糊集Ｓ同时存在并－普通分解形式：Ｓ＝∪λ∈［－１,１］λＳλ和交－普通分解形式：Ｓ＝∩λ∈［－１,１］λＳλ;这两种分解形式是建立双枝模糊推理理论,双枝模糊控制理论的理论基础．（２）单枝模糊集Ａ（Ｌ．Ａ．ＺａｄｅｈＦｕｚｚｙＳｅｔＡ）的并－普通分解定理,交－普通分解定理是双枝模糊集Ｓ的并－普通分解定理,交－普通分解定理的特例．     

(严格)强相关均衡的一致性公理化(英文)

R.J.Aumann指出Nash均衡集含于相关均衡集中.1996年.B.Peleg和S.Tijs给出(严格)强Nash均衡的两个一致性公理化.本文试图把B.Peleg和S.Tijs的这两个结果推广到(严格)强相关均衡中去.     

Root-restricted Kleenean rotations

We generalize the Kleene theorem to the case where nonassociative products are used. For this purpose, we apply rotations restricted to the root of binary trees.     

Adaptive discrete neural observer design for nonlinear systems with unknown time‐delay

This paper focuses on the adaptive observer design for nonlinear discrete‐time MIMO systems with unknown time‐delay and nonlinear dynamics. The delayed states involved in the system are arguments of a nonlinear function and only the estimated delay is utilized. By constructing an appropriate Lyapunov–Krasovskii function, the delay estimation error is considered in the observer parameter design. The proposed method is then extended to the system with a nonlinear output measurement equation and the delayed dynamics. With the help of a high‐order neural network (HONN), the requirement for a precise system model, the linear‐in‐the‐parameters (LIP) assumption of the delayed states, the Lipschitz or norm‐boundedness assumption of unknown nonlinearities are removed. A novel converse Lyapunov technical lemma is also developed and used to prove the uniform ultimate boundedness of the proposed observer. The effectiveness of the proposed results is verified by simulations. Copyright © 2010 John Wiley & Sons, Ltd.     

一个用于指针程序验证的自动定理证明器的设计与实现

对高可信软件需求的增加使得指针程序的验证成为近期的研究热点.指针逻辑作为Hoare逻辑的扩展,可以对指针程序进行精确的分析.介绍一个针对指针逻辑的自动定理证明器的设计和实现,描述了一些算法.实验结果表明,该定理证明器可以完全自动的证明用类C语言编写的关于单链表,双链表和二叉树的指针程序的验证条件,并生成机器可检查的证明.     

一种提取目标图像最小外接矩形的快速算法

在图像分类与识别算法研究中,目标几何特征的提取通常需要计算目标图像的最小外接矩形以获取长、宽等属性。针对该特点,提出一种利用顶点链码与离散格林理论相结合的方式提取目标图像的最小外接矩形的算法。该算法只需根据顶点链中垂直或水平方向上的点坐标即可求出目标的面积、形心和主轴。基于顶点链码和离散格林的主轴法和旋转法可快速求出目标的最小外接矩形。实验结果表明,旋转法的运算速度是现有算法的2倍左右,主轴法的速度又比旋转法快速2倍左右。     

基于贝叶斯理论的支持向量机综述

支持向量机(SVM)以其坚实的理论基础,和在机器学习领域表现出的良好推广性能,获得了越来越广泛的关注。为更好地推进其发展,科研工作者们借鉴统计学中经典的贝叶斯理论,做了大量工作,例如:引进贝叶斯理论中先验知识、后验概率等概念,改进支持向量机中的判别准则;或利用贝叶斯理论估计支持向量机中的参数w、正规化参数以及核参数等。目前已取得不错的效果,使支持向量机理论更具有实用价值。     

有缺指派下的信念修正逻辑

经典的AGM信念修正理论和以D-P假设为代表的迭代信念修正理论都是以完全指派为可能世界而进行的理论研究.把这些研究推广到有缺指派的领域中与完全指派为每个原子命题符号都指派真假值不同,有缺指派是一个三值指派,它可以为每个原子命题符号指派真、假和不确定三值之一.以有缺指派为可能世界,对D-P系统进行了推广,证明了相应的表示定理.