Real nonparametric regression using complex wavelets

Summary.  Wavelet shrinkage is an effective nonparametric regression technique, especially when the underlying curve has irregular features such as spikes or discontinuities. The basic idea is simple: take the discrete wavelet transform of data consisting of a signal corrupted by noise; shrink or remove the wavelet coefficients to remove the noise; then invert the discrete wavelet transform to form an estimate of the true underlying curve. Various researchers have proposed increasingly sophisticated methods of doing this by using real-valued wavelets. Complex-valued wavelets exist but are rarely used. We propose two new complex-valued wavelet shrinkage techniques: one based on multiwavelet style shrinkage and the other using Bayesian methods. Extensive simulations show that our methods almost always give significantly more accurate estimates than methods based on real-valued wavelets. Further, our multiwavelet style shrinkage method is both simpler and dramatically faster than its competitors. To understand the excellent performance of this method we present a new risk bound on its hard thresholded coefficients.     

区域经济增长与环境质量演进关系模型研究——基于环境库兹涅茨曲线

从社会福利最大化角度出发,通过设定物品消费偏好指数,建立两物品模型,推导出了区域环境最佳投资水平;在此基础上,从理论上证明了环境库兹涅茨曲线存在的依据以及在环境质量最低点和环境质量发生根本性好转的转折点的社会总投资水平。最后,得出环境质量演化过程曲线取决于社会经济发展状况,它与非环境物品生产函数和排污生产函数的技术参数、居民收入水平以及对环境物品和非环境物品的消费偏好以及国民收入分配政策等有关,而非仅仅与经济增长状况有关。     

偏微分积分方程的周期边值问题

本文用上下解方法结合特征线理论讨论了形如 U_t+f(t,x)U_x=g(t,x,u,Tu) u(0,x)=u(2π,x) (1)的一阶偏微分积分方程解的存在性与唯一性,进而用双边迭代的方法给出其求解的程序。     

菲利普斯曲线在中国的有效性研究

从基本的菲利普斯曲线理论出发,提出了新的适应性预期模型,并以此为基础建立附加预期的菲利普斯曲线方程,进而估计出我国近年来的自然失业率水平,由此证明了菲利普斯曲线在我国的有效性,并描述了预期因素对实际通货膨胀水平的影响。最后结合实证分析结果提出解决我国通货膨胀和失业问题的建议,如保证货币政策的连贯性、加强信息披露、解决结构性失业问题等。     

Cold wars and hot issues: management of responsibilities

This paper provides a review of the Ninth International Conference of the Academy of Human Resource Development (Asia Chapter) that took place in Shanghai, China on 11–14 November 2010. In addition to providing a brief review of the pre-conference workshops and keynote addresses, this paper presents the outcomes of the conference using four main themes: (1) corporate training; (2) the development of key personnel; (3) career development and work-life balance; and (4) organizational learning and learning organization. In conclusion, the authors share their thoughts on the contributions of international conferences to the field of human resource development.     

Functional sliced inverse regression analysis

Most of the usual multivariate methods have been extended to the context of functional data analysis. Our contribution concerns the study of sliced inverse regression (SIR) when the response variable is real but the regressor is a function. In the first part, we show how the relevant properties of SIR remain essentially the same in the functional context under suitable conditions. Unfortunately, the estimation procedure used in the multivariate case cannot be directly transposed to the functional one. Then, we propose a solution that overcomes this difficulty and we show the consistency of the estimates of the parameters of the model.     

环境与经济如何双赢--环境库兹涅茨曲线引发的思考

环境库兹涅茨曲线揭示了环境污染与人均收入水平之间存在倒"U"形关系,20世纪90年代后,西方环境经济学界的许多研究不断证实或充实了这一结论.在明确环境库兹涅茨曲线的作用机理和作用条件的基础上,发展中国家完全有可能利用后发优势,突破该曲线,缩小环境与经济两难区间,扩大双赢区间.我国目前仍处于环境与经济两难区间,可通过合理的政策调控、提高环境意识、积极培植可持续发展"实验田"等措施,超越传统的单纯依靠经济实力治理环境的思路,尽快走出两难境地,实现生态环境建设的跨越式发展.     

人口、经济增长对环境影响的库兹涅茨曲线分析——以昆山市为例

采用昆山市1991-2007年人口、经济相关数据,对昆山市人口、经济发展现状和环境质量进行了库兹涅茨曲线拟合分析,发现昆山市目前工业废水排放量、工业废气排放量分别与经济增长呈倒N型和正N型曲线关系,工业固体废物排放方面则不存在明显曲线,人口增长速度较快但对环境影响不明显。这说明昆山市目前已进入人口、经济增长与环境质量关系转折的关键点,转折的实现需要积极的环境政策响应。     

区域经济增长与环境质量演进关系模型研究——基于环境库兹涅茨曲线

从社会福利最大化角度出发,通过设定物品消费偏好指数,建立两物品模型,推导出区域环境最佳投资水平;从理论上证明了环境库兹涅茨曲线存在的依据以及在环境质量最低点和环境质量发生根本性好转的转折点的社会总投资水平。最后,得出环境质量演化过程曲线取决于社会经济发展状况,它与非环境物品生产函数和排污生产函数的技术参数、居民收入水平以及对环境物品和非环境物品的消费偏好以及国民收入分配政策等有关,而非仅仅与经济增长状况有关。     

对菲利普斯曲线不稳定性的一种新解释

通货膨胀率和失业率之间关系,是菲利普斯曲线描述的基本内容,也是经济学争论的焦点之一。在所有有关菲利普斯曲线的讨论中,假定劳动供给曲线是正斜率曲线是一个基本前提。但劳动供给曲线不一定是正斜率,它既可能是正斜率、负斜率,也可能是水平或垂直线,正是由于劳动供给曲线的不稳定性,导致了通货膨胀率和失业率之间关系的不稳定,因此依据菲利普斯曲线来决策并不可靠。