LS estimation of periodic autoregressive models with non-Gaussian errors: a simulation study

In this article, the least squares (LS) estimates of the parameters of periodic autoregressive (PAR) models are investigated for various distributions of error terms via Monte-Carlo simulation. Beside the Gaussian distribution, this study covers the exponential, gamma, student-t, and Cauchy distributions. The estimates are compared for various distributions via bias and MSE criterion. The effect of other factors are also examined as the non-constancy of model orders, the non-constancy of the variances of seasonal white noise, the period length, and the length of the time series. The simulation results indicate that this method is in general robust for the estimation of AR parameters with respect to the distribution of error terms and other factors. However, the estimates of those parameters were, in some cases, noticeably poor for Cauchy distribution. It is also noticed that the variances of estimates of white noise variances are highly affected by the degree of skewness of the distribution of error terms.     

关于量子控制系统的哲学思考

环境对量子控制系统的消相干揭示了一个事实,即量子世界里的系统将是一种全新的系统,它是某种开放的、数学的、并且是基于量子逻辑的系统。笔者认为,假如仍然还是立足经典思维,则系统的独立性将难以得到保证,传统的整体论也将变得自相矛盾。只有发展全新的"量子整体论",并在这种新的框架下去审视和建构量子系统,我们才有可能重新获得某种连贯一致的整体论。     

Bayesian Network Structure Learning with Permutation Tests

In literature there are several studies on the performance of Bayesian network structure learning algorithms. The focus of these studies is almost always the heuristics the learning algorithms are based on, i.e., the maximization algorithms (in score-based algorithms) or the techniques for learning the dependencies of each variable (in constraint-based algorithms). In this article, we investigate how the use of permutation tests instead of parametric ones affects the performance of Bayesian network structure learning from discrete data. Shrinkage tests are also covered to provide a broad overview of the techniques developed in current literature.     

金融资产的动态非线性相关:一个新的模型

基于Kendall’sτ秩相关系数的优越性和定义,本文提出了新的具有明确经济意义的动态条件相关copula模型,将常用的Gaussian、Clayton和Gumbel函数统一根据该演化方程实现动态化,构造出三种Kendall’sτ动态条件相关copula模型,可用于刻画不同的相关模式。这些模型不仅参数少、容易估计,避免了现有动态条件相关copula模型构建方法各异导致的在实证中不利于比较的缺点,而且能够进行多步向前预测,有效地减少了进行样本外预测时的计算量,从而为刻画时变、非线性、非对称性和尾部相关等复杂的动态相关模式提供了新方法。     

Tail asymptotic of discounted aggregate claims with compound dependence under risky investment

This paper considers the tail asymptotic of discounted aggregate claims with compound dependence under risky investment. The price of risky investment is modeled by a geometric Lévy process, while claims are modeled by a one-sided linear process whose innovations further obeying a so-called upper tail asymptotic independence. When the innovations are heavy tailed, we derive some uniform asymptotic formulas. The results show that the linear dependence has significant impact on the tail asymptotic of discounted aggregate claims but the upper tail asymptotic independence is negligible.     

Estimation and simulation of conditional hazard function in the quasi-associated framework when the observations are linked via a functional single-index structure

We consider the estimation of the conditional hazard function of a scalar response variable Y given a Hilbertian random variable X when the observations are linked via a single-index structure in the quasi-associated framework. We establish the pointwise almost complete convergence and the uniform almost complete convergence (with the rate) of the estimate of this model. A simulation is given to illustrate the good behavior in the practice of our methodology.     

Family Background and the Process of Ability Formation*

This paper takes a sociometric approach to the process of skills formation in children as they mature into adults. Honda suggests that meaningful communication with family as a child is the determining factor that raises those abilities (ability β ¹ ) that fall outside of scholastic aptitude – motivation, personal relations skills, personality, and emotions. Along with considering the results of Honda's thesis, I have constructed an operating hypothetic model that includes two additional factors: the financial state of the family during childhood, and the transition of the communication target from within the family to a target outside the family. The data for this investigation were then verified. From the results, the direct effect of the observed family communication, when isolated from other influencing variables in the formation of abilities β, is not as decisive a factor as Honda emphasized. It was clear that the financial status of the family played a role, as did the indirect results of the intermediary shift from communication within the family to outside the family (the process of children becoming socially independent). The results of this analysis show that we should not necessarily be looking for the decisive factors of abilities β within the family; if anything, it reflects the existence of a formative route for abilities β that capitalizes on the resources outside the family. Based on the above, the results also show the potential for the introduction of social intervention to address the disparity and inequality in skills formation, and the possible anticipation of more rationality in the overblown discourse surrounding the role of the family in facilitating educational ability.     

苏格兰独立问题的历史与未来

苏格兰自1707年并入英联合王国后,要求独立的呼声始终未断,2007年苏格兰民族党成为执政党后,独立呼声愈演愈烈。"苏格兰的未来将由苏格兰人民来决定",2014年9月18日苏格兰进行独立公投。从历史沿革、政治权势博弈两个方面入手可把握苏格兰独立问题的整体脉络。将英国政治制度中的务实传统与当前多重利益因素综合考虑,可诠释苏格兰独立问题的产生原因、英国政府同意公投的实用主义倾向。     

Independence test in high-dimension using distance correlation and power enhancement technique

Abstract

This paper is concerned with independence test in high-dimension. A new test statistic is proposed with two terms: one is based on the modified distance correlation statistic, the other is constructed to enhance the power under sparse alternatives. Asymptotic properties of the test statistic are discussed under some regular conditions. The finite-sample simulations exhibit its superiority over some existing procedures. Finally, a real data example illustrates the proposed test.