Smoothing parameter selection in nonparametric regression using an improved Akaike information criterion

Many different methods have been proposed to construct nonparametric estimates of a smooth regression function, including local polynomial, (convolution) kernel and smoothing spline estimators. Each of these estimators uses a smoothing parameter to control the amount of smoothing performed on a given data set. In this paper an improved version of a criterion based on the Akaike information criterion (AIC), termed AIC_C, is derived and examined as a way to choose the smoothing parameter. Unlike plug-in methods, AIC_C can be used to choose smoothing parameters for any linear smoother, including local quadratic and smoothing spline estimators. The use of AIC_C avoids the large variability and tendency to undersmooth (compared with the actual minimizer of average squared error) seen when other 'classical' approaches (such as generalized cross-validation (GCV) or the AIC) are used to choose the smoothing parameter. Monte Carlo simulations demonstrate that the AIC_C-based smoothing parameter is competitive with a plug-in method (assuming that one exists) when the plug-in method works well but also performs well when the plug-in approach fails or is unavailable.     

新巴塞尔协议中信用风险管理IRB法解析

为研究商业银行的信用风险管理问题,对新巴塞尔协议中信用风险管理IRB法进行系统分析,概括其基本框架,并通过详细解析其设定的4种风险要素函数来解释目前我国商业银行在运用各种信用风险管理模型时存在“黑箱”的原因,同时,探讨该方法与各种信用风险管理模型的兼容关系,通过解析信用风险管理模型中各种风险要素函数设定的内在逻辑关系,总结目前我国商业银行应用IRB法时存在的各种数据估计上的困难,从而得出应对各种困难的对策。     

A regression-based smoothing spline Monte Carlo algorithm for pricing American options in discrete time

American options in discrete time can be priced by solving optimal stopping problems. This can be done by computing so-called continuation values, which we represent as regression functions defined recursively by using the continuation values of the next time step. We use Monte Carlo to generate data, and then we apply smoothing spline regression estimates to estimate the continuation values from these data. All parameters of the estimate are chosen data dependent. We present results concerning consistency and the estimates’ rate of convergence.     

体验型产品消费行为的羊群效应及机理研究——基于电影行业消费行为的实证解释

互联网环境下消费者购买体验型产品时对网络信息的依赖性很大。因此,研究社交媒体影响下体验型产品的消费者决策选择行为具有现实意义。本文以电影行业的票房偏离及消费跟风现象为切入点,探究体验型产品的羊群效应并对其产生的内在机理进行解释。采集艺恩资讯的票房数据以及豆瓣的电影基本信息及影评等数据作为研究样本,从消费者\"羊群行为\"视角分析其对电影票房的影响。研究发现：在控制了质量等内生性影响之后,消费者羊群效应依然存在;产品特征信息对羊群效应起到了调节作用,从而形成理性跟随;采用预期差异模型可以解释消费者实现理性跟随的过程。研究结论对于电影行业宏观政策制定及对体验型产品合理进行营销推广提供了理论基础与实证依据。     

三向剖分域上带有边界条件的二元二次样条插值与逼近

本文主要用B—网方法研究了平行六边形区域在三向剖分△_6~3下,带有I—型边界条件的二元二次样条插值的存性性、唯一性及逼近度问题。     

3600/40矿棉板成型机设计

矿棉板已成为公共建筑吊顶材料的首选,但其关键设备成型机还主要依靠进口。自主开发的3600/40矿棉板成型机,采取湿法长网抄取成型,多点伺服电气控制,配有高浓网前箱、针形辊、上真空辊、蒸气喷洒、印花辊等先进装置,料板厚度自动可调,具有产量大,易操作,适应低容重和高矿棉两种配方工艺,具有能耗低、质量稳定、节水等优点,可完全替代进口。