小波框架的彩色图像泊松去噪

噪声是影响图像质量的重要因素,噪声的存在导致图像的某些特征细节不能被辨识以及图像的信噪比下降,所以图像去噪是图像处理中的一个重要问题.本文提出了基于小波框架的彩色图像的泊松去噪模型.在该模型中,赋权的l²项作为保真项,包含小波框架的l¹项作为正则项.同时,又提出了解决该模型的重新赋权的split Bregman算法.最后,利用仿真实验以及PSNR（峰值信噪比）指标对该模型的去噪效果进行评估,评估结果表明该算法可行、有效.     

苏州市区信息通讯企业空间集聚与新企业选址

高科技产业是全球化背景下城市发展与区域竞争的关键,但是高科技产业发展空间极不平衡,空间要素显著影响高科技企业区位选择及空间集聚。针对现有研究主要集中在国家、省等大尺度单元,本文引入空间点模式分析方法,探讨了1996-2006年间苏州市区不同空间尺度上信息通讯企业的时空集聚特征。研究发现:在0~6km的尺度上,信息通讯企业表现出明显的集聚特征,并随着尺度的增加呈现出倒U型集聚趋势;随着时间的推移,企业空间集聚的热点地区逐渐从老城区向外围推移,但是集聚峰区依然主要分布在老城区及其外围的国家和省级开发区;同时,新企业的选址与原有企业的分布特征表现出很强的相关性。运用计数模型的计量结果也表明企业集聚特征对新企业区位选择具有显著影响,同时起作用的还有地方政府政策影响下的开发区建设、城市内外交通条件、自然环境条件等因素。     

The first and the second e of the extreme value distribution,EV1

In the peak over threshold model resulting in the Extreme-value distribution, type I, (EV1) the firste of the distribution function is based on the Poisson number of exceedances, and the seconde arises from the Exponentially distributed magnitudes.This paper, on the one hand, generalises the Poisson model to the (positive and negative) Binomial distribution, and, on the other hand, the Exponential distribution is generalised to the Generalised Pareto distribution. Lack of fit with respect to the Poisson and Exponential distribution is measured by statistics derived from those which would be locally most powerful if the estimates of the location and scale parameter were equal to the true parameter values. Ways of combining both statistics are discussed.     

不同粒径大理岩样声学特性的研究

基于不同粒径大理岩样进行了超声波测试,研究了浸水时间和宏观裂隙对波速的影响规律,以及岩样声学参数的离散程度。结果表明,浸水时间对岩样的纵波速度有很大的影响,但对横波速度影响甚微;宏观裂隙的存在降低了岩样的纵波速度,波幅降低程度与岩样破坏程度有关;随着岩石平均粒径的增大,岩石的声学参数先减小后增大,并非单调关系,而且动态泊松比的变化幅度明显高于其他声学参数,不能作为材料的力学参数表征岩石的变形特性。     

Statistical control chart for regime identification in volcanic time series

In an important paper, Mulargia et al. (1987) address the importance of quantitative and objective identification of different regimes of a volcano. They develop a procedure based on the two-sample Kolmogorov-Smirnov (K-S) statistic. The K-S test is a general-purpose test that discriminates between two data sets as belonging to two different regimes based on their empirical distribution functions. The empirical distribution function is designed to describe the aggregate behavior of the volcanic activity, and it is constructed from the orders of the length of the collected repose times in each data set. In this article, we use the idea of statistical process control to distinguish between the variation inherent in the observed repose times and the extraordinary variation that signals a real change in the regimes. We construct a table of control limits, and we demonstrate the procedure of regime identification based on a simple control chart. It shows a point outside the control limits almost as soon as the process enters a new regime. The basis of the statistical process control mechanism is a simple Poisson process, which is state of the art. The proposed control charting procedure is an eruption by eruption procedure, which follows the original chronological order of the eruptions. This procedure is applied to the eruptive history of the Mount Etna volcano. The application shows schematically that the procedure presents a visual interpretation of the identified regimes and can be practically translated for tabular or manual use.     

剩余时差校正及泊松比反演

利用突出泊松比变化的Shuey简化方程推导出逐点计算泊松比的反演公式.在泊松比反演之前，对地震数据进行剩余时差校正，可以使振幅随炮检距（或入射角）的变化趋势更明显，可以提高反演的精度.通过对理论模型及实际资料的处理，说明这种反演方法是可行的，由反演结果可以预测低泊松比异常，寻找天然气.     

一类广义Hamilton系统的辛格式

通过引人泊松括号，分析了无限维Hamilton的性质，并将其推广到广义Hamilton系统，且从理论和实用角度讨论了这类广义Hamilton系统的辛格式构造问题，从而为辛几何算法在一般的时间发展方程的数值求解提供新的具体途径。     

Strip Transect Sampling to Estimate Object Abundance in Homogeneous and Non-homogeneous Poisson Fields: a Simulation Study of the Effects of Changing Transect Width and Number

This paper investigates the use of strip transect sampling to estimate object abundance when the underlying spatial distribution is assumed to be Poisson. A design-based rather than model-based approach to estimation is investigated through computer simulation, with both homogeneous and non-homogeneous fields representing individual realizations of spatial point processes being considered. Of particular interest are the effects of changing the number of transects and transect width (or alternatively, coverage percent or fraction) on the quality of the estimate. A specific application to the characterization of unexploded ordnance (UXO) in the subsurface at former military firing ranges is discussed. The results may be extended to the investigation of outcrop characteristics as well as subsurface geological features.     

Solution of an unstable axisymmetric Cauchy–Poisson problem of dispersive water waves for a spectrum with compact support

 It has been known that the axisymmetric Cauchy–Poisson problem for dispersive water waves is well posed in the sense of stability. Thereby time evolution solutions of wave propagation depend continuously on initial conditions. However, in this paper, it is demonstrated that the axisymmetric Cauchy–Poisson problem is ill posed in the sense of stability for a certain class of initial conditions, so that the propagating solutions do not depend continuously on the initial conditions. In order to overcome the difficulty of the discontinuity, Landweber–Fridman's regularization, famous and well known in applied mathematics, are introduced and investigated to learn whether it is applicable to the present axisymmetric wave propagation problem. From the numerical experiments, it is shown that stable and accurate solutions are realized by the regularization, so that it can be applicable to the determination of the ill-posed Cauchy–Poisson problem.     

Hypotheses for earthquake occurrences

Very little work has been done in generating alternatives to the Poisson process model. The work reported here deals with alternatives to the Poisson process model for the earthquakes and checks them using empirical data and the statistical hypothesis testing apparatus. The strategy used here for generating hypotheses is to compound the Poisson process. The parameter of the Poisson process is replaced by a random variable having prescribed density function. The density functions used are gamma, chi and extended (gamma/chi). The original distribution is then averaged out with respect to these density functions. For the compound Poisson processes the waiting time distributions for the future events are derived. As the parameters for the various statistical models for earthquake occurrences are not known, the problem is basically of composite hypothesis testing. One way of designing a test is to estimate these parameters and use them as true values. Momentmatching is used here to estimate the parameters. The results of hypothesis testing using data from Hindukush and North East India are presented.