纽结的Homflypt多项式

介绍了一类重要的纽结不变量,即Honmflypt多项式,证明了两个环链的Homlypt多项式相等的必要条件是它们的环绕数相等。此外,研究了它同纽结Jones多项式和Vassiliev不变量之间的关系。     

A non-iterative posterior sampling algorithm for linear quantile regression model

In this article, a non-iterative posterior sampling algorithm for linear quantile regression model based on the asymmetric Laplace distribution is proposed. The algorithm combines the inverse Bayes formulae, sampling/importance resampling, and the expectation maximization algorithm to obtain independently and identically distributed samples approximately from the observed posterior distribution, which eliminates the convergence problems in the iterative Gibbs sampling and overcomes the difficulty in evaluating the standard deviance in the EM algorithm. The numeric results in simulations and application to the classical Engel data show that the non-iterative sampling algorithm is more effective than the Gibbs sampling and EM algorithm.     

Measuring Social Tension from Income Class Segregation

We develop an index that effectively measures the level of social tension generated by income class segregation. We adopt the basic concepts of between-group difference (or alienation) and within-group similarity (or identification) from the income [bi]polarization literature; but we allow for asymmetric degrees of between-group antagonism in the alienation function, and construct a more effective identification function using both the relative degree of within-group clustering and the group size. To facilitate statistical inference, we derive the asymptotic distribution of the proposed measure using results from U-statistics. As the new measure is general enough to include existing income polarization indices as well as the Gini index as special cases, the asymptotic result can be readily applied to these popular indices. Evidence from the Panel Study of Income Dynamics data suggests that, while the level of social tension shows an upward trend over the sample period of 1981 to 2005, government’s taxes and transfers have been effective in reducing the level of social tension significantly.     

应用化学专业创新人才培养实践教学环节的思考与探索

以培养学生的创新精神和实践能力为主线,论述应用化学专业实践教学的重要性。对如何深化实践教学改革、提高实验、实习教学水平、提升毕业设计(论文)质量进行有益的探索。     

专业知识教学环节改革的探索与实践

结合教学改革实践,论述了在专业知识传授过程中,不但要注重专业知识的系统性和完整性,更要注重提高学生专业方面的综合素质,并提出了在专业知识传授环节中增加综合训练周提高毕业生专业方面综合素质的改革途径。     

印度对中印跨境河流水关系的认知及战略选择

近年来,印度对中印在跨境河流水关系中的不平衡问题非常重视.其中,水文信息不对称以及收益不平衡是印度对水关系不平衡的两个主要认知.基于中印边境的互动历史,印度在对水关系的认知形成中往往会夸大中国的敌意与威胁.据此,印度试图通过建立制度框架、将中印水争议国际化以及竞争性开发跨境河流水资源的战略思维,平衡中国在雅鲁藏布江—布拉马普特拉河水关系中的优势地位.然而受水外交两面性特征和内政的掣肘,印度平衡战略的影响有限,而且更强化了其对雅鲁藏布江—布拉马普特拉河战略安全收益的重视,并使未来中印双方基于水资源共同利益进行合作的难度加大.     

新时期社会转型的中国经验——新时期社会转型与和谐社会构建问题战略层面上的比较价值

中国新时期社会转型与和谐社会构建问题,是中国经济社会发展进程中提出和探索的具有全局性、战略性的双重命题,是对我国现代社会发展规律的基本认识,也是对中国改革与发展进程的一种新的理解.这双重命题必须同时上升为执政党和政府的时代性理念,必须置于中国特色社会主义这一"核心主题"的主流分析框架之下;必须从同等程度意义上,上升为执政党和政府的战略性决策层面;改革开放30年的今天,迫切需要分析中国特色社会主义的现代社会转型与和谐社会构建的内在联系;必须从真理性与价值性之统一的角度解析中国特色的现代社会转型与和谐社会构建问题双重命题的同等程度范畴的现实价值.     

A new nonlinear asymmetric cointegration approach using error correction models

In this article, two new powerful tests for cointegration are proposed. The general idea is based on an intuitively appealing extension of the traditional, rather restrictive cointegration concept. In this article, we allow for a nonlinear, but most importantly a different, asymmetric convergence process to account for negative and positive changes in our cointegration approach. Using Monte Carlo simulations we verify, that the estimated size of the first test depends on the unknown value of a signal-to-noise ratio q. However, our second test—which is based on the original ideas of Kanioura and Turner—is more successful and robust in the sense that it works in all of the different evaluated situations. Furthermore it is shown to be more powerful than the traditional residual based Enders and Siklos method. The new optimal test is also applied in an empirical example in order to test for potential nonlinear asymmetric price transmission effects on the Swedish power market. We find that there is a higher propensity for power retailers to rapidly and systematically increase their retail electricity prices subsequent to increases in Nordpool's wholesale prices, than there is for them to reduce their prices subsequent to a drop in wholesale spot prices.     

Bootstrap forecast intervals for asymmetric volatilities via EGARCH model

Bootstrap forecast intervals are developed for volatilities having asymmetric features, which are accounted for by fitting EGARCH models. A Monte-Carlo simulation compares the proposed forecast intervals with those based on GARCH fittings which ignore asymmetry. The comparison reveals substantial advantage of addressing asymmetry through EGARCH fitting over ignoring it as the conventional GARCH forecast. The EGARCH forecast intervals have empirical coverage probabilities closer to the nominal level and/or have shorter average lengths than the GARCH forecast intervals. The finding is also supported by real dataset analysis of Dow–Jones index and financial times stock exchange (FTSE) 100 index.     

Bayesian expectile regression with asymmetric normal distribution

In this paper, we adopt the Bayesian approach to expectile regression employing a likelihood function that is based on an asymmetric normal distribution. We demonstrate that improper uniform priors for the unknown model parameters yield a proper joint posterior. Three simulated data sets were generated to evaluate the proposed method which show that Bayesian expectile regression performs well and has different characteristics comparing with Bayesian quantile regression. We also apply this approach into two real data analysis.