正交型与非正交型消元兼容的一种线代数方程解法

求解大型稀疏线性代数方程组 AX=C (1)常采用的直接解法有二种,最普遍的是LU分解法(即Gauss消去法,或称非正交型消元法).为了提高精度,常采用部分主元素或全部主元素法.但是,这一措施对一个非零元有确定分布的方程组,每次分解而形成的三角阵L和U其稀疏结构却是不同的.因此,每次分解用于寻找主元以及修改阵中非零元连接表的额外工作量很大,严重地降低了求解速度.文的作者做过一些试验,其结果见表1.他们的试验是在111机上用BCY语言实现的.试验表明,按主容限法(为兼顾稀疏性而对全主元降低了要求的全主元素法)作LU分解,总工作量往往正比于n~q(n为方程组阶数),其中q>1.为了避免选主元     

一类广义系统的迭代学习控制

在对广义系统进行标准分解的基础上, 研究了含脉冲快子系统的迭代学习控制问题. 通过 Frobenius 范数给出了快子系统在 P 型学习律作用下收敛的充分性条件, 同时通过梯度法给出求解增益矩阵的方法. 其次, 讨论了单输入单输出不确定广义系统的迭代学习控制问题, 通过优化方法给出该系统在 P 型学习律作用下, 系统实际输出尽可能快地收敛到理想输出的增益矩阵的选择方法.     

部分变量迭代法求解几何循环约束

在对几何约束进行求解时，一般先要进行适当分解，然后再根据分解得到的求解次序进行依次求解。当同时进行求解的约束数量较多时，必须采用数值解法。如果这样的循环约束中变量的数量较多，则采用全部变量迭代的方法会导致计算不稳定，且计算时间较长。本文提出了部分变量进行迭代的方法，大大降低了迭代变量的个数，增加了计算的的稳定性，缩短了计算时间。     

非线性规划U-D分解方法及其在神经网络训练中的应用

提出一种有效的U-D分解DFP和BFGS算法.该算法解决了H阵的正定性问题,保 证了算法的数值稳定性,并大大提高了计算效率.对H阵的计算量分析表明,该算法的计算效 率比普通方法高20%,比普通平方根方法高0.4n(n为H阵维数)倍.神经网络训练的应用 表明,新算法比普通DFP和BFGS方法更有效、更准确.     

一种高数值精度的P3P问题半闭式解法*

根据有限数目的参考点,通过二维单目观测图像估计三维目标的姿态参数(又称PnP问题,perspective-n-point)是计算机视觉研究中的一个经典难题。当参考点的数目n<6时,PnP问题为高度非线性问题并可能存在多个可行解。目前求解PnP问题的方法主要分为迭代解法和闭式解法两类。迭代解法数值精度高,但是只能收敛到多解中的一个解,无法同时得到全部可行解;闭式解法的优点是可以一次得到全部可行解,但是现有算法在数值精度和数值稳定性上要逊于迭代解法。针对以上问题,以P3P问题为研究对象,提出一种可以同时得到全部可行解并具有高数值精度的半闭式解法,并通过详细的实验验证该方法的有效性。     

面向图分割问题的确定性退火控制算法

图分割问题是一种典型的NP-hard 问题, 如何对其进行高效求解一直都是学界和工业界的一个难题. 本文构建了一种新型的确定性退火控制算法, 提供了图分割问题的一种高质量近似解法. 算法主要由两部分构成: 全局收敛的迭代过程以及屏障函数最小点组成的收敛路径. 我们证明了,当屏障因子从足够大的实数降为0, 沿着一系列由屏障问题最小点组成的收敛路径可以得到图分割问题的一种高质量的近似解. 仿真计算结果表明本文所构建算法相比已有方法的优越性     

基于改进迭代收缩阈值算法的微观3D重建方法

迭代收缩阈值算法（ISTA）求解离焦深度恢复动态优化问题时,采用固定迭代步长,导致算法收敛效率不佳,使得重建的微观3D形貌精度不高。为此,提出一种基于加速算子梯度估计和割线线性搜索的方法优化ISTA——FL-ISTA。首先,在每一次迭代中,由当前点和前一个点的线性组合构成加速算子重新进行梯度估计,更新迭代点;其次,为了改变迭代步长固定的限制,引入割线线性搜索,动态确定每次最优迭代步长;最后,将改进的迭代收缩阈值算法用于求解离焦深度恢复动态优化问题,加快算法的收敛速度、提高微观3D形貌重建的精度。在对标准500 nm尺度栅格的深度信息重建实验中,与ISTA、快速ISTA （FISTA）和单调快速ISTA （MFISTA）相比,FL-ISTA收敛速度均有所提升,重建的深度信息值下降了10个百分点,更接近标准500 nm栅格尺度;与ISTA相比,FL-ISTA重建的微观3D形貌均方差（MSE）和平均误差分别下降了18个百分点和40个百分点。实验结果表明,FL-ISTA有效提升了求解离焦深度恢复动态优化问题的收敛速度,提高了微观3D形貌重建的精度。     

一种求解机器人操作器运动学逆问题的分解解法

本文提出了一种新的求解操作器运动学逆问题的分解解法,它是对现有的代数解法和几何解法的综合.文中结合 PUMA 操作器对该解法作了具体阐述.     

基于最小二乘自适应迭代的宽带波束形成算法

大部分时域恒定束宽宽带波束形成算法的权值拟合运算量较大,导致实用性大大降低.本文给出一种基于最小二来自适应迭代的恒定束宽波束形成器设计方法,同时将RLS迭代算法应用于滤波器组设计中.本文方法易于实现,不受阵形及阵元指向性限制,不受迭代步长影响,且能快速收敛.理论推导及仿真实验验证了本文方法的有效性.     

基于策略迭代算法的连续时间线性Markov跳变系统非零和微分反馈Nash控制

针对一类连续时间线性Markov跳变系统,本文提出了一种新的策略迭代算法用于求解系统的非零和微分反馈Nash控制问题.通过求解耦合的数值迭代解,以获得具有线性动力学特性和无限时域二次成本的双层非零和微分策略的Nash均衡解.在每一个策略层,采用策略迭代算法来计算与每一组给定的反馈控制策略相关联的最小无限时域值函数.然后,通过子系统分解将Markov跳变系统分解为N个并行的子系统,并将该算法应用于跳变系统.本文提出的策略迭代算法可以很容易求解非零和微分策略所对应的耦合代数Riccati方程,且对高维系统有效.最后通过仿真示例证明了本文设计方法的有效性和可行性.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。