On a Bivariate Distribution with Exponential Marginals

A new bivariate distribution with exponential marginals has been introduced by Singpurwalla & Youngren (1993). This distribution is absolutely continuous and has a single parameter. It was originally motivated as the failure model for a two-component system experiencing damage described by a shot–noise process. The purpose of this paper is two-fold. The first is to articulate on several aspects of this distribution, in particular, its genesis, the nature of its dependence, its correlation structure, and its generalized version as a two-parameter bivariate distribution with exponential marginals. The second purpose of this paper is more general. Prompted by the need to explain certain features of the bivariate distribution, it is found useful to introduce a new notion in reliability and survival analysis. This notion is called the "hazard potential", of an item susceptible to failure. The hazard potential is viewed as a kind of hidden parameter of failure models that delineates a cause and effect relationship in reliability.     

The asymptotic behaviour of a class of L.-estimators under long-range dependence

This paper obtains asymptotic representations of a class of L-estimators in a linear regression model when the errors are a function of long-range-dependent Gaussian random variables. These representations are then used to address some of the efficiency robustness properties of L-estimators compared to the least-squares estimator. It is observed that under the Gaussian error distribution, each member of the class has the same asymptotic efficiency as that of the least-squares estimator. The results are obtained as a consequence of the asymptotic uniform linearity of some weighted empirical processes based on long-range-dependent random variables.     

Semiparametric estimation for seasonal long-memory time series using generalized exponential models

We consider a generalized exponential (GEXP) model in the frequency domain for modeling seasonal long-memory time series. This model generalizes the fractional exponential (FEXP) model [Beran, J., 1993. Fitting long-memory models by generalized linear regression. Biometrika 80, 817–822] to allow the singularity in the spectral density occurring at an arbitrary frequency for modeling persistent seasonality and business cycles. Moreover, the short-memory structure of this model is characterized by the Bloomfield [1973. An exponential model for the spectrum of a scalar time series. Biometrika 60, 217–226] model, which has a fairly flexible semiparametric form. The proposed model includes fractionally integrated processes, Bloomfield models, FEXP models as well as GARMA models [Gray, H.L., Zhang, N.-F., Woodward, W.A., 1989. On generalized fractional processes. J. Time Ser. Anal. 10, 233–257] as special cases. We develop a simple regression method for estimating the seasonal long-memory parameter. The asymptotic bias and variance of the corresponding long-memory estimator are derived. Our methodology is applied to a sunspot data set and an Internet traffic data set for illustration.     

基于Copula函数的金融市场尾部相关性分析

在常规极大似然估计法中，Copula函数的参数估计受边缘分布函数拟和的影响较大，鉴于此，用基于秩的极大似然法估计Copula函数的参数，并结合常见的4类双参数非对称BBx—Copula函数，对民生银行和浦发银行这两只股票的尾部相关性进行实证分析，结果表明股票市场在低迷时期的尾部相关性高于活跃时期的尾部相关性。     

Exact inference for multivariate ordered alternatives

In this paper we discuss three types of ordered alternatives ordered location, stochastic ordering and quadrant dependence. We prove that quadrant dependence is the more general among the three. Then we consider a conditional tests for the equality of c distributions against quadrant dependence in a multivariate setup. An exact simultaneous testing procedure based on dependent conditional tests is presented. Two applications to real data are also given.     

弱者心态与“五四”现实主义文学初潮

新文学发轫期 ,弱者文化心态直接影响了人们接受西方文学思潮的视野和审美趣味 ,也决定了文学的内容和表达生活的方式。这一心态成为现实主义文学迅速发展的心理基础。     

考虑消费者双通道心理账户和参照依赖的动态定价问题研究

为分析消费者双通道心理账户及参照依赖行为对企业长期利润的影响,本文探讨了在一般支付、提前支付及延迟支付方案下的动态定价问题。采用了离散时间动态规划分析思路,讨论了两周期模型在不同支付方案下最优价格、最优利润的关系,进一步将动态定价行为扩展到了无限期的情形,分析了在各种支付方案下的稳态价格,结果表明当需求函数是线性时,提前支付与延迟支付下的稳态价格要大于一般支付下的稳态价格;当初始参考价格较高(较低)时,最优价格策略类似于撇脂定价策略(渗透定价策略)。最后通过数值分析,比较了双通道心理账户各参数对不同支付方案长期总利润的影响,并总结了厂商如何选择最优支付方案以获取更高利润的建议。该思路对基于行为的动态定价研究具有一定的借鉴意义。     

Multiresolution anomaly detection method for fractional Gaussian noise

Driven by network intrusion detection, we propose a MultiResolution Anomaly Detection (MRAD) method, which effectively utilizes the multiscale properties of Internet features and network anomalies. In this paper, several theoretical properties of the MRAD method are explored. A major new result is the mathematical formulation of the notion that a two-scaled MRAD method has larger power than the average power of the detection method based on the given two scales. Test threshold is also developed. Comparisons between MRAD method and other classical outlier detectors in time series are reported as well.     

试论"认知方式"与"外语习得"

认知方式是一个心理学的述语,用来描述一个人观察、感知、组织、分析、回忆其经验或信息时所表现出来的特殊方式.认知方式可分为场独立和场依存两种.场独立使人具有重建结构的能力,场依存使人具有社交能力,二者以不同的方式促进外语习得.外语习得不仅涉及到语言分析能力和重建结构能力,而且涉及在实际交往中的语言交际能力,因此学好一种外语必须两种能力都具备.     

Likelihood-based panel cointegration test in the presence of a linear time trend and cross-sectional dependence

This article proposes a new likelihood-based panel cointegration rank test which extends the test of Örsal and Droge (2014 Örsal, D. D. K., Droge, B. (2014). Panel cointegration testing in the presence of a time trend. Computational Statistics and Data Analysis 76:377–390.[Crossref], [Web of Science ®] , [Google Scholar]) (henceforth panel SL test) to dependent panels. The dependence is modelled by unobserved common factors which affect the variables in each cross-section through heterogeneous loadings. The data are defactored following the panel analysis of nonstationarity in idiosyncratic and common components (PANIC) approach of Bai and Ng (2004 Bai, J., Ng, S. (2004). A PANIC attack on unit roots and cointegration. Econometrica 72(4):1127–1177.[Crossref], [Web of Science ®] , [Google Scholar]) and the cointegrating rank of the defactored data is then tested by the panel SL test. A Monte Carlo study demonstrates that the proposed testing procedure has reasonable size and power properties in finite samples.