基于小波变换的股票异常点检测研究

异常点的存在会导致股票数据模型的波动预测功能失效,因此,在对股票数据进行建模分析时,异常点的检测是至关重要的。文章对股票数据通过GARCH模型处理得到的残差进行小波变换,能够准确有效地检测异常点并很好的克服了异常点的"遮蔽效应"。最后,实验证明,该方法的效果良好。     

联合均值与方差模型的统计诊断

研究了联合均值与方差模型,考虑了基于数据删除模型的参数估计和统计诊断,比较删除模型与未删除模型相应统计量之间的差异。首次提出了基于联合均值与方差模型的诊断统计量和局部影响分析。通过模拟研究和实例分析,给出了不同的诊断统计量来判别异常点或强影响点,研究表明提出的理论和方法是有用和有效的。     

SV模型局部分析的稳健性研究

随机波动（SV）模型是一种重要的具有隐性波动的时间序列模型。本文在对SV模型进行Cook局部影响分析的基础上，探讨方法对参数估计精度的稳健性，从而评价局部影响分析方法应用在时间序列模型的优劣。     

数据删除模型下的高杠杆点度量

针对删除k个数据点的线性回归模型,文章提出了一种新的影响度量矩阵。通过对其对角元的研究,得到了高杠杆点的性质,并推广了删除单个数据点的高杠杆点度量的回归模型。在此基础上给出了岭估计下的影响度量矩阵和高杠杆点度量。实例验证表明,该诊断方法是可行且有效的。     

数据删除模型在GDP诊断中的应用

文章利用数据删除模型,对1996~2007年的国内生产总值(GDP)数据进行统计诊断,判定2007年和2004年的数据为异常值点或强影响点。在此基础上,利用SPSS软件,建立了支出法与生产法的GDP之差与最终消费支出、资本形成总额和货物与服务净出口的有效线性回归关系,指出两种计算方法的GDP差值主要来源于货物与服务净出口,在一定程度上解释了GDP统计的差异。     

基于时间序列孤立点检测的可疑外汇资金交易识别研究

尽管洗钱模式复杂多变,但洗钱行为在整个金融活动中只占有极少的比例,这给监测洗钱交易增加了难度.作为数据挖掘重要方法之一的孤立点分析是在大数据集中发现有趣小模式的有效方法.文章提出了一种适用于可疑外汇资金交易识别的孤立点检测方法,可以持续地从大量的日常交易中发现极少数的与正常交易显著不同的异常交易.从孤立点分析角度,提出了基于非频繁模式挖掘思想和概念漂移处理的混合属性空间上时间序列孤立点检测方法;从可疑金融交易识别的角度,提出了对每天持续动态产生的海量金融交易数据进行分析的一种新思路.     

一类非线性测量误差模型的保形法曲率及其局部影响

保形法曲率是Poon W Y和Poon Y S(1997)从微分几何的观点出发提出来的诊断模型局部影响的一种统计量,它将影响曲率标准化在[0,1]范围内,并提供了判定局部影响大小的阙值,可看作Cook(1986)局部影响方法的进一步推广。本文采用保形法曲率方法来诊断具有正态先验分布的非线性测量误差模型的局部影响,并对常见的两种扰动模型给出了局部影响的计算公式。最后通过实例分析验证了文中诊断统计量的有效性。     

基于Bayes后验概率的自变量与异常点的同时识别

本文基于自变量与异常点识别隐变量的联合Bayes后验概率,给出了自变量与异常点同时识别的一般方法,且利用Gibbs抽样降低了Bayes后验概率的计算复杂度。其次,针对多值序次数据模型自变量与异常点的同时识别展开详细讨论,给出了同时识别的具体过程。最后通过模拟算例展示了本文方法的有效性。     

含均值结构变点时间序列的贝叶斯单位根检验

针对ADF和PP检验对含有均值结构变点时间序列的“伪检验”问题,文章基于贝叶斯理论,先运用贝叶斯因子模型选择的方法检测时序结构变点位置,再在结构变点已知的情况下运用置信区间和贝叶斯因子两种方法检验序列是否存在单位根,并用Monte Carlo模拟方法进行仿真,验证该方法的有效性。研究发现：是否考虑均值结构变点对时间序列的单位根检验有着重要的影响,不考虑结构突变而进行常规的单位根检验会产生误判;贝叶斯方法能够有效检测含有均值结构变点时间序列的变点位置,并能提高单位根检验功效。     

多重共线性的诊断方法

在对经济现象作建模分析与预测过程中,常常会遇到多重共线问题。基于多重共线的病态模型预测完全失效,文章就多重共线的诊断理论方法作了阐述,尤其是对多重共线影响点的诊断方法作了介绍,特别是对Walker法与主成分法对多重共线影响点的诊断作了比较。     

Influence diagnostics in Gaussian spatial linear models

Spatial linear models have been applied in numerous fields such as agriculture, geoscience and environmental sciences, among many others. Spatial dependence structure modelling, using a geostatistical approach, is an indispensable tool to estimate the parameters that define this structure. However, this estimation may be greatly affected by the presence of atypical observations in the sampled data. The purpose of this paper is to use diagnostic techniques to assess the sensitivity of the maximum-likelihood estimators, covariance functions and linear predictor to small perturbations in the data and/or the spatial linear model assumptions. The methodology is illustrated with two real data sets. The results allowed us to conclude that the presence of atypical values in the sample data have a strong influence on thematic maps, changing the spatial dependence structure.     

对中国各地区能源强度空间影响的实证研究

运用莫兰指数考察了地区能源强度的空间自相关性,并在能源要素禀赋差距指标和地理邻近矩阵的基础上创建了一个空间计量权重矩阵。通过Matlab7.0的空间计量工具箱,分别运用空间滞后面板数据模型和空间误差面板数据模型对中国地区间能源强度的空间效应进行了实证检验,结果证明了空间聚集效应的存在,邻近地区的能源强度确实会对目标地区的能源强度产生影响。     

The internal norm approach to influence diagnostics

Cook and Weisberg (1982) describe the external and internal norm approaches to assessing the influence of a subset of data on least squares regression estimates. External norms base influence measurement on the repeated sampling theory of the assumed model, while internal norm measures judge the influence of a size-k subset relative to all size-k subsets within the given data. Although intuitively appealing, intemal norms have been largely ignored in favor of external norms due to computational considerations. The purpose of this article is to present the internal norm approach as a viable alternative to external norm influence measurement. In addition to discussing conceptual and computational issues, empirical evidence is provided to show that the internal norm interpretation of influence is different from that of its external counterparts. Finally, comparisons are drawn between external calibration and internal scaling for evaluating influence measure values.     

Influential data points in predictive logistic models

The influence of individual points in an ordinal logistic model is considered when the aim is to determine their effects on the predictive probability in a Bayesian predictive approach. Our concern is to study the effects produced when the data are slightly perturbed, in particular by observing how these perturbations will affect the predictive probabilities and consequently the classification of future cases. We consider the extent of the change in the predictive distribution when an individual point is omitted (deleted) from the sample by use of a divergence measure suggested by Johnson (1985) as a measure of discrepancy between the full data and the data with the case deleted. The methodology is illustrated on some data used in Titterington et al. (1981).     

Logistic discrimination using robust estimators: An influence function approach

Logistic regression is frequently used for classifying observations into two groups. Unfortunately there are often outlying observations in a data set and these might affect the estimated model and the associated classification error rate. In this paper, the authors study the effect of observations in the training sample on the error rate by deriving influence functions. They obtain a general expression for the influence function of the error rate, and they compute it for the maximum likelihood estimator as well as for several robust logistic discrimination procedures. Besides being of interest in their own right, the influence functions are also used to derive asymptotic classification efficiencies of different logistic discrimination rules. The authors also show how influential points can be detected by means of a diagnostic plot based on the values of the influence function     

Influence diagnostics for the Grubbs's model

In this paper we consider applications of local influence (Cook, 1986) to evaluate small perturbations in the model or in data sets of several measuring devices, assuming Grubbs's model. Different perturbation schemes are investigated and an application is considered to two real data sets.     

Bayesian local influence analysis of skew-normal spatial dynamic panel data models

The existing studies on spatial dynamic panel data model (SDPDM) mainly focus on the normality assumption of response variables and random effects. This assumption may be inappropriate in some applications. This paper proposes a new SDPDM by assuming that response variables and random effects follow the multivariate skew-normal distribution. A Markov chain Monte Carlo algorithm is developed to evaluate Bayesian estimates of unknown parameters and random effects in skew-normal SDPDM by combining the Gibbs sampler and the Metropolis–Hastings algorithm. A Bayesian local influence analysis method is developed to simultaneously assess the effect of minor perturbations to the data, priors and sampling distributions. Simulation studies are conducted to investigate the finite-sample performance of the proposed methodologies. An example is illustrated by the proposed methodologies.     

Influential observations in GARCH models

This paper examines local influence assessment in generalized autoregressive conditional heteroscesdasticity models with Gaussian and Student-t errors, where influence is examined via the likelihood displacement. The analysis of local influence is discussed under three perturbation schemes: data perturbation, innovative model perturbation and additive model perturbation. For each case, expressions for slope and curvature diagnostics are derived. Monte Carlo experiments are presented to determine the threshold values for locating influential observations. The empirical study of daily returns of the New York Stock Exchange composite index shows that local influence analysis is a useful technique for detecting influential observations; most of the observations detected as influential are associated with historical shocks in the market. Finally, based on this empirical study and the analysis of simulated data, some advice is given on how to use the discussed methodology.     

A Sequential Point Process Model and Bayesian Inference for Spatial Point Patterns with Linear Structures

Abstract. We introduce a flexible spatial point process model for spatial point patterns exhibiting linear structures, without incorporating a latent line process. The model is given by an underlying sequential point process model. Under this model, the points can be of one of three types: a ‘background point’ an ‘independent cluster point’ or a ‘dependent cluster point’. The background and independent cluster points are thought to exhibit ‘complete spatial randomness’, whereas the dependent cluster points are likely to occur close to previous cluster points. We demonstrate the flexibility of the model for producing point patterns with linear structures and propose to use the model as the likelihood in a Bayesian setting when analysing a spatial point pattern exhibiting linear structures. We illustrate this methodology by analysing two spatial point pattern datasets (locations of bronze age graves in Denmark and locations of mountain tops in Spain).