Spline smoothing over difficult regions

Summary. It is occasionally necessary to smooth data over domains in R ² with complex irregular boundaries or interior holes. Traditional methods of smoothing which rely on the Euclidean metric or which measure smoothness over the entire real plane may then be inappropriate. This paper introduces a bivariate spline smoothing function defined as the minimizer of a penalized sum-of-squares functional. The roughness penalty is based on a partial differential operator and is integrated only over the problem domain by using finite element analysis. The method is motivated by and applied to two sample smoothing problems and is compared with the thin plate spline.     

Thin plate regression splines

Summary. I discuss the production of low rank smoothers for d  ≥ 1 dimensional data, which can be fitted by regression or penalized regression methods. The smoothers are constructed by a simple transformation and truncation of the basis that arises from the solution of the thin plate spline smoothing problem and are optimal in the sense that the truncation is designed to result in the minimum possible perturbation of the thin plate spline smoothing problem given the dimension of the basis used to construct the smoother. By making use of Lanczos iteration the basis change and truncation are computationally efficient. The smoothers allow the use of approximate thin plate spline models with large data sets, avoid the problems that are associated with 'knot placement' that usually complicate modelling with regression splines or penalized regression splines, provide a sensible way of modelling interaction terms in generalized additive models, provide low rank approximations to generalized smoothing spline models, appropriate for use with large data sets, provide a means for incorporating smooth functions of more than one variable into non-linear models and improve the computational efficiency of penalized likelihood models incorporating thin plate splines. Given that the approach produces spline-like models with a sparse basis, it also provides a natural way of incorporating unpenalized spline-like terms in linear and generalized linear models, and these can be treated just like any other model terms from the point of view of model selection, inference and diagnostics.     

一种基于现场总线和PLC的中厚板轧机伺服控制系统应用分析

随着社会经济的发展,以及计算机和PLC控制技术的发展,中厚板生产企业面临着激烈的市场竞争。因此,对于中厚板生产企业来说,要想使利润达到最大化,就必须实现低成本、高质量以及高成材率的指标。首先了解PLC在中厚板轧机中实现自动化控制的要点,针对西门子PLC、Profibus DP现场总线技术组成中厚板轧机的伺服控制系统,从控制系统的硬件设计、系统软件的设计、系统工艺的控制功能以及系统优化所实现的功能进行探讨和优势分析。     

矩形件排样的流程和算法设计

针对人工矩形件排样效率低、耗时长,且不能保证得到板材利用率为最优方案的问题,通过研究人工矩形件排样 的过程,提出了一种下料系统流程和矩形件排样的启发式与遗传相结合的算法。研究结果表明：所设计的下料系统流程 能够充分利用原材料库和余料库,且避免生成更多的余料;通过文中设计的启发式和遗传相结合的矩形件排样算法,能 够快速搜索出近似总体最优的排样方案。该设计方案能够提高板材利用率,同时减少更多余料的产生。     

质子交换膜燃料电池金属双极板制备工艺研究进展

双极板是质子交换膜燃料电池的核心部件,需求量巨大,金属双极板是新兴的双极板形式。为了初步探寻商品 化制备金属双极板工艺的方向,文章综述了近年来质子交换膜燃料电池金属双极板的制造工艺。将金属双极板制造工 艺分类为减材、增材以及等材3个方面,并对各类工艺优劣进行对比研究;同时从燃料电池金属双极板的商品化角度对 各类制造工艺进行详细分析。提出了硬模和软模冲压工艺是商品化制备金属双极板的可行工艺方法。     

中国交通拥挤收费的理论分析、经验借鉴与初步构想

随着交通机动化和汽车私人化迅猛发展,主要城市都不同程度地遭受着交通拥挤的困扰.以往缓解交通拥挤问题主要依靠供给政策和行政措施,然而实践证明运用供给政策调节往往陷入“交通拥挤—扩建道路—私人交通增多—公交需求减少—交通更加拥挤“的恶性循环.在给出了Downs-Thomson及Braess两种通勤悖论的基础上,分别证明在某些条件下提高道路交通容量是无效甚至起反作用;分析了交通拥挤收费的经济学原理,证明拥挤收费可以有效解决通勤悖论;介绍了拥挤收费的国际经验;探讨了中国实施拥挤收费的必要性和可行性,强调中国应该结合供需政策,运用收费机制纠正市场失灵,引导人们科学出行,从而缓解道路拥挤,发展绿色城市交通.     

D型水力碎浆机轻杂质排放系统的优化

某纸厂废纸制浆生产线上,45 m3D型水力碎浆机轻渣排放口易被大块杂质堵住,导致轻杂质不能及时排出,为 此对轻杂质排放系统重新优化设计。首先设计了L形结构的挡流板,使未碎解的大块杂质和纸板不能沿着槽体内浆流 的方向直接冲进轻杂质口,而是被轻杂质口内的吸力抽走;其次设计了用于调节轻杂质流量的调节阀,以根据实际情况 调节轻杂质入口的吸力;最后取消轻杂质排放系统内的管道连接弯头,从而减少管道内流体的阻力。改进后的碎浆机系 统运行稳定可靠,轻杂质排放顺畅。     

古代文论的弹丸之喻

The projectile metaphor is a classical analogy in ancient literary theory. Around its own characteristics of circle and rotation, it integrates with philosophy and aesthetics. It has gradually enriched its meaning in the process of succession, and has derived many forms, such as the release of bullets and the round in the plate. It realizes its critical function through intertextuality and terms forming     

法拉第对阿拉果铜盘实验现象的研究和解释

详细介绍了法拉第研究和解释阿拉果铜盘实验现象的过程,阐明了在法拉第的研究过程中,对阿拉果铜盘实验现象的研究与其电磁感应现象的发现及研究之间的紧密联系。说明法拉第对阿拉果铜盘实验现象的研究和解释极大地促进了其对电磁感应现象的研究,是其电磁感应原理应用于实践研究的一个重要胜利,促进了电磁感应原理的传播和承认。     

试析新疆大山水画板块的完善

新疆草地占总面积的30.8%,是我国牧业大区,因而新疆大山水画研究所关于构建创作和理论体系的"四大板块"不够完善,应当增加"大草原"板块。此外,新疆的大山不止天山,大的山脉还有昆仑山和阿尔泰山,我们应当把"大天山"改为"大三山",即"大三山、大沙漠、大戈壁、大草原、大绿洲"五大板块。