PROJECTION-PURSUIT BASED PRINCIPAL COMPONENT ANALYSIS： A LARGE SAMPLE THEORY

The principal component analysis （PCA） is one of the most celebrated methods in analysing multivariate data. An effort of extending PCA is projection pursuit （PP）, a more general class of dimension-reduction techniques. However, the application of this extended procedure is often hampered by its complexity in computation and by lack of some appropriate theory. In this paper, by use of the empirical processes we established a large sample theory for the robust PP estimators of the principal components and dispersion matrix.     

一类两参数指数鞅

设W=(W_z:z∈R_(zo))是关于L-S测度F的广义Brown单,本文证明了当X是两参数循序可测的Ganss过程,且时,则两参数指数过程是Rzo上的一强鞅。     

线性时滞系统的P和PI控制器稳定参数集算法

针对任意阶线性时滞系统,提出了一种确定比例(P)控制器稳定参数集的解析算法.该算法基于Nyquist稳定判据,将控制参数的无限约束转化为有限约束,从而能够容易地确定P控制器的稳定参数集.然后应用该算法进一步讨论了比例积分(PI)控制器对线性时滞系统的镇定问题.稳定参数集的建立为时滞过程P和PI控制器的设计和在线调节提供了方便.该方法适用于任意阶的稳定、不稳定或非最小相位时滞过程.     

一种柱球头铣刀新型刃口的数学模型

通过对传统柱球头铣刀传统刃口设计中数学模型的推导与分析，指出了传统方法设计与制造中存在较大困难，提出了介于与径线成定角ψ和等螺距刃口之间的新设计方法，并给出了二轴联动和非数控加工的方案与数学模型，为这类同是较大的回转刀具的研制提供了新的参考。     

“It was Hard to Come to Mutual Understanding …”—The Multidimensionality of Social Learning Processes Concerned with Sustainable Natural Resource Use in India, Africa and Latin America

Sustainable natural resource use requires that multiple actors reassess their situation in a systemic perspective. This can be conceptualised as a social learning process between actors from rural communities and the experts from outside organisations. A specifically designed workshop oriented towards a systemic view of natural resource use and the enhancement of mutual learning between local and external actors, provided the background for evaluating the potentials and constraints of intensified social learning processes. Case studies in rural communities in India, Bolivia, Peru and Mali showed that changes in the narratives of the participants of the workshop followed a similar temporal sequence relatively independently from their specific contexts. Social learning processes were found to be more likely to be successful if they 1) opened new space for communicative action, allowing for an intersubjective re-definition of the present situation, 2) contributed to rebalance the relationships between social capital and social, emotional and cognitive competencies within and between local and external actors.     

硬车削技术及其应用

分析了硬车削加工的特点、硬车削加工所需的条件以及硬车削技术在生产中的应用，并对其关键技术进行了探讨，指出理车削技术是一种高效、洁净的工艺方法，具有广泛的应用前景。     

以人为本营造安全生产的全方位保障机制

从以人为本的视角分析安全生产的重要意义，主张从理念创新、制度建设、科技研发与推广等重要方面，加强安全生产工作，真正建立起“关爱生命，关注安全”的全方位保障机制。     

随机环境SMDP的弱收敛逼近

在随机环境半马氏决策过程的计算方法中,直接从最优方程求最优策略或求ε最优值函数都会遇到困难,本文讨论的弱收敛逼近提供解决这类问题近似计算的一种方法     

氮化层组织与干式滚动磨损性能的研究

本文利用X光衍射仪、金相显微镜和声发射等手段对38CrMoAlA,35CrMo,40Cr钢经纯氨离子氮化,纯氨加钛离子氮化以及气体氨化后的渗层组织,硬度及干式滚动磨损性能进行了观察和分析。结果表明:加钛离子氮化可以显著提高工件渗层的硬度;但由于脆性增加而不利于干式滚动磨损;离子氮化处理后抗干式滚动磨损性能最佳。