电加热器敏捷设计系统研究

提出了一种电加热器产品的敏捷设计平台结构，研究了CAD系统与PDM／ERP软件的接口、数据通信及基于产品定制的参数化设计方法，阐述了CAD软件与SQL Server数据库相联的二次开发及基于图库的多文档参数化设计技术。在AutoCAD软件平台上采用C＋＋语言及Objec—tARX技术，开发了整个系统功能，实现了优化计算、参数化绘图、数据管理、工艺设计一体化等，提高了产品设计质量和设计速度。     

A plug-in the number of knots selector for polynomial spline regression

A plug-in the number of interior knots (NIKs) selector is proposed for polynomial spline estimation in nonparametric regression. The existence and properties of the optimal NIKs for spline regression are established by minimising the weighted mean integrated squared error. We obtain plug-in formulae for the optimal NIKs based on the theoretical results of asymptotic optimality, and develop strategies for choosing the NIKs of the spline estimator. The proposed NIKs selection method is tested on our simulated data with quite satisfactory performance, and is illustrated by analysing a fossil data set.     

浅谈AutoCAD2000绘图新特性

文中对AutoCAD2000较AutoCADR14新增的功能进行了介绍。AutoCAD2000所具有的新特性大幅度提高了用户的设计工作效率。同时指出了AutoCAD2000存在的不足。     

基于AutoCAD技术房屋管理系统的开发与应用

本文介绍了北京化工大学国有资产管理处利用AutoCAD技术建立了全校公用房电子图库,完成了房屋资源动态计算机管理,实现了用房及时修改和查询的功能,简化了人工操作,提高了工作效率。     

土木工程AutoCAD教学探讨

指出了当前AutoCAD教学中存在的问题,认为AutoCAD教学改革应优化课程设置,应优化教材编选,应使用多样化的教学方法,应注重培养学生的学习兴趣,应注重使用新的设计软件并注重设计理念的表达.     

AutoCAD软件在机械制图教学中的应用研究

把AutoCAD软件应用于《机械制图》课程的教学,是对《机械制图》课程传统的教学内容教学方法和手段的重大改革。教学实践证明:该方法提高了教学效果和效率,有利于学生计算机绘图能力的培养和提高。     

Marcinkiewicz–Zygmund and ordinary strong laws for empirical distribution functions and plug-in estimators

Both Marcinkiewicz–Zygmund strong laws of large numbers (MZ-SLLNs) and ordinary strong laws of large numbers (SLLNs) for plug-in estimators of general statistical functionals are derived. It is used that if a statistical functional is ‘sufficiently regular’, then an (MZ-)SLLN for the estimator of the unknown distribution function yields an (MZ-)SLLN for the corresponding plug-in estimator. It is in particular shown that many L-, V- and risk functionals are ‘sufficiently regular’ and that known results on the strong convergence of the empirical process of α-mixing random variables can be improved. The presented approach does not only cover some known results but also provides some new strong laws for plug-in estimators of particular statistical functionals.     

A comparative simulation study of data-driven methods for estimating density level sets

Density level sets are mainly estimated using one of three methodologies: plug-in, excess mass, or a hybrid approach. The plug-in methods are based on replacing the unknown density by some nonparametric estimator, usually the kernel one. Thus, the bandwidth selection is a fundamental problem from an applied perspective. Recently, specific selectors for level sets have been proposed. However, if some a priori information about the geometry of the level set is available, then excess mass algorithms can be useful. In this case, the problem of bandwidth selection can be avoided. The third methodology is a hybrid of the others. It assumes a mild geometric restriction on the level set and it requires a pilot nonparametric estimator of the density. One interesting open question concerns the performance of these methods. In this work, existing methods are reviewed, and two new hybrid algorithms are proposed. Their practical behaviour is compared through extensive simulation study.     

Bayesian inverse problems with heterogeneous variance

We consider inverse problems in Hilbert spaces under correlated Gaussian noise, and use a Bayesian approach to find their regularized solution. We focus on mildly ill-posed inverse problems with fractional noise, using a novel wavelet-based vaguelette–vaguelette approach. It allows us to apply sequence space methods without assuming that all operators are simultaneously diagonalizable. The results are proved for more general bases and covariance operators. Our primary aim is to study posterior contraction rate in such inverse problems over Sobolev classes and compare it to the derived minimax rate. Secondly, we study effect of plugging in a consistent estimator of variances in sequence space on the posterior contraction rate. This result is applied to the problem with error in forward operator. Thirdly, we show that empirical Bayes posterior distribution with a plugged-in maximum marginal likelihood estimator of the prior scale contracts at the optimal rate, adaptively, in the minimax sense.     

AutoCAD常用接口方式研究

AutoCAD系统提供有多种接口方式,如.SCR文件、.DXF文件等.研究AutoCAD常用接口方式的特点、生成方法、应用环境、各自的优势以及相互之间的关系等,有助于我们在实践中更好地利用它们.