Unconditional distributions obtained from conditional specification models with applications in risk theory

Bivariate distributions, specified in terms of their conditional distributions, provide a powerful tool to obtain flexible distributions. These distributions play an important role in specifying the conjugate prior in certain multi-parameter Bayesian settings. In this paper, the conditional specification technique is applied to look for more flexible distributions than the traditional ones used in the actuarial literature, as the Poisson, negative binomial and others. The new specification draws inferences about parameters of interest in problems appearing in actuarial statistics. Two unconditional (discrete) distributions obtained are studied and used in the collective risk model to compute the right-tail probability of the aggregate claim size distribution. Comparisons with the compound Poisson and compound negative binomial are made.     

建立和完善企业规章制度 促进企业和谐稳定发展

依法建立和完善劳动规章制度,是保证用人单位各项工作顺利进行的必要措施。文章以广西柳州钢铁（集团）公司钢星公司为例,分析了用规章制度规范企业与员工的劳动行为,维护企业和谐稳定的具体措施。     

Option Pricing with Heterogeneous Expectations

This paper re-derives the finite mixture option pricing model of Ritchey (1990), based on the assumption that the option investors hold heterogeneous expectations about the parameters of the lognormal process of the underlying asset price. By proving that the model admits no riskless arbitrage, this paper justifies that the entire family of finite mixture of lognormal distributions is a desirable candidate set for recovering the risk-neutral probability distributions from contemporaneous options quotes. The parametric method derived from the model is significantly simpler than the nonparametric method of Rubinstein (1994) for recovering the risk-neutral probability distributions from contemporaneous option prices.     

Bayesian modeling of joint and conditional distributions

In this paper, we study a Bayesian approach to flexible modeling of conditional distributions. The approach uses a flexible model for the joint distribution of the dependent and independent variables and then extracts the conditional distributions of interest from the estimated joint distribution. We use a finite mixture of multivariate normals (FMMN) to estimate the joint distribution. The conditional distributions can then be assessed analytically or through simulations. The discrete variables are handled through the use of latent variables. The estimation procedure employs an MCMC algorithm. We provide a characterization of the Kullback–Leibler closure of FMMN and show that the joint and conditional predictive densities implied by the FMMN model are consistent estimators for a large class of data generating processes with continuous and discrete observables. The method can be used as a robust regression model with discrete and continuous dependent and independent variables and as a Bayesian alternative to semi- and non-parametric models such as quantile and kernel regression. In experiments, the method compares favorably with classical nonparametric and alternative Bayesian methods.     

影响新疆稳定和长治久安的主要因素及对策分析

新疆地处亚欧大陆腹地,邻近中亚、南亚、西亚国家,是我国对外开放的重要门户,是欧亚大陆通道的重要枢纽。新疆发展和稳定,关乎全国改革发展稳定大局,维护新疆社会形势稳定和长治久安意义重大。     

试论稳定工作在开放式公园管理中的重要作用

城市公园是市民游乐、休闲、健身的重要场所,也是极易引发不稳定因素的敏感部位。特别是随着社会的进步,政府各项便民措施的出台,大部分城市公园都在陆续实行开放式管理。这一变化,无疑将给公园管理带来更大的难度。同时,也给稳定工作带来了新的课题,稳定工作在城市公园开放式管理中很关键。所以,只有将其切实纳入工作议程,加强组织领导,才能保证其落到实处,为城市公园开放式管理的有序顺畅、和谐自然提供可靠的保障。     

Robust estimation with flexible parametric distributions: estimation of utility stock betas

The distributions of stock returns and capital asset pricing model (CAPM) regression residuals are typically characterized by skewness and kurtosis. We apply four flexible probability density functions (pdfs) to model possible skewness and kurtosis in estimating the parameters of the CAPM and compare the corresponding estimates with ordinary least squares (OLS) and other symmetric distribution estimates. Estimation using the flexible pdfs provides more efficient results than OLS when the errors are non-normal and similar results when the errors are normal. Large estimation differences correspond to clear departures from normality. Our results show that OLS is not the best estimator of betas using this type of data. Our results suggest that the use of OLS CAPM betas may lead to erroneous estimates of the cost of capital for public utility stocks.     

Asymptotically optimal estimation of smooth functionals for interval censoring, part 2

Estimation in the interval censoring model is considered. A class of smooth functionals is introduced, of which the mean is an example. We consider case 2, with two observation times for each unobservable event time, in the situation that the observation times cannot become arbitrarily close to each other. It is proved that the nonparametric maximum likelihood estimator of the functional asymptotically reaches the information lower bound.     

Spillover effects and conditional dependence

A better understanding of cross-market linkages and interactions would help to better manage international financial exposure. So far, no attempt has been made to investigate the degree of price and volatility spillovers in a non-Gaussian conditional framework. We present a new model for these transmission mechanisms that relies on asymmetric-t marginal distributions and a copula function to characterize the conditional dependence. Rendering the dependence parameter time varying, we investigate how the dependence structure is affected by stock return innovations.     

铁路局管辖范围增大的管理问题思考

针对南昌铁路局管辖范围扩大后面临的实际问题,按照现代企业组织管理的基本原理,提出实施分层分类、分层分权管理,并对应该做好的产业结构和生产力布局调整、建立管理新机制、规范分层管理决策程序、提高人员素质等相关工作进行了探析,以期对铁路局直管站段的管理工作有所裨益。