Variable Selection and Regularization in Quantile Regression via Minimum Covariance Determinant Based Weights

The importance of variable selection and regularization procedures in multiple regression analysis cannot be overemphasized. These procedures are adversely affected by predictor space data aberrations as well as outliers in the response space. To counter the latter, robust statistical procedures such as quantile regression which generalizes the well-known least absolute deviation procedure to all quantile levels have been proposed in the literature. Quantile regression is robust to response variable outliers but very susceptible to outliers in the predictor space (high leverage points) which may alter the eigen-structure of the predictor matrix. High leverage points that alter the eigen-structure of the predictor matrix by creating or hiding collinearity are referred to as collinearity influential points. In this paper, we suggest generalizing the penalized weighted least absolute deviation to all quantile levels, i.e., to penalized weighted quantile regression using the RIDGE, LASSO, and elastic net penalties as a remedy against collinearity influential points and high leverage points in general. To maintain robustness, we make use of very robust weights based on the computationally intensive high breakdown minimum covariance determinant. Simulations and applications to well-known data sets from the literature show an improvement in variable selection and regularization due to the robust weighting formulation.     

电力载波自动抄表系统

阐述了电力载波自动抄表系统的工作原理,系统组成及其主要特点,并对该系统主要元件的功能及特性作了详细的介绍。该系统的推广应用势在必行,前景广阔。     

DropDownList控件在Web信息系统设计中的应用

asp．net是当前开发Web网络应用系统的主流技术之一。在开发Web用户界面时,需用多种用户数据输入控件,DropDownList就是常用的控件之一。文中概述了asp．net技术以及DropDownList控件的特性,结合具体实例对DropDownList控件应用进行了探讨。阐述了DropDownList控件的动态绑定数据库、联动功能、自动刷新问题的解决以及可输入选项的实现方法,对于开发Web应用系统有一定的实用价值。     

Can climate sensitivity be estimated from short-term relationships of top-of-atmosphere net radiation and surface temperature?

Increasing the knowledge in climate radiative feedbacks is critical for current climate studies. This work focuses on short-term relationships between global mean surface temperature and top-of-atmosphere (TOA) net radiation. The relationships may be used to characterize the climate feedback as suggested by some recent studies. As those recent studies, an energy balance model with ocean mixed layer and both radiative and non-radiative heat sources is used here. The significant improvement of current model is that climate system memories are considered.Based on model simulations, short-term relationship between global mean surface temperature and TOA net radiation (or the linear striation feature as suggested by previous studies) might represent climate feedbacks when the system had no memories. However, climate systems with the same short-term feedbacks but different memories would have a similar linear striation feature. This linear striation feature reflects only fast components of climate feedbacks and may not represent the total climate feedback even when the memory length of climate systems is minimal. The potential errors in the use of short-term relationships in estimations of climate sensitivity could be big. In short time scales, fast climate processes may overwhelm long-term climate feedbacks. Thus, the climate radiative feedback parameter obtained from short-term data may not provide a reliable estimate of climate sensitivity. This result also suggests that long-term observations of global surface temperature and TOA radiation are critical in the understanding of climate feedbacks and sensitivities.     

CBR:一种支持工作流过程语义验证的组件级 化简方法

目前的工作流过程验证方法多数侧重控制流特性验证,与数据或资源信息相结合的验证尚未得到很好发展.然而,业务过程的目标实现依赖于控制流、数据流和资源三维基本观点的协作.保证过程的目标实现需要验证这三维观点协作的正确性,称为语义验证.该文侧重讨论大型、灵活的过程语义验证问题.首先,形式化定义过程模型,综合体现三维基本观点,表达完整的过程语义,并使用基于组件的思想,具有一定可扩展性和灵活性.然后,通过探讨组件间的协作逻辑,提出基于组件的化简方法(Component Based Reduction,CBR)和化简规则,为过程语义验证提供有力支持.     

AIS—NC多类型开放队列网络性能分析

本文研究了基于网络计算机会计信息系统性能分析方法，针对会计信息系统结构特点及硬件资源请求类型，抽象出三种系统响应模式．据此，构建了AIS-NC多类型开放队列网络性能模型，并且给出了性能分析的步骤和方法．举例说明了该方法的应用．该方法对其他多类型开放队列网络性能分析具有借鉴意义．     

NDS服务器的配置与优化

所讨论的就是在齐齐哈尔大学校园网和教育教学科研网接口带宽有限的前提下，怎样通过优化校园网络主DNS服务器的配置，实现域名解析后的超链接子操作在公网上进行，从而提高对学校WWW等服务器访问的速度。     

虚拟制造技术发展策略浅析

通过分析虚拟制造技术的重大作用与其它先进制造技术的关系，从多方面论述了发展虚拟制造技术的策略及途径，希望为制造业的发展做些有益的探索。     

WL2.1彩电遥控系统软件开发及相关电路设计

开发有自己特色的遥控系统是国内电视机工厂面临的一个新课题。本文简要介绍了现已投入大批量应用的ＷＬ２．１彩电遥控系统软件的特点，以及相关扫口电路的设计。