贸易中介研究综述

贸易中介在国际贸易发展中发挥的作用越来越受到重视,回顾近年来国内外贸易中介文献,从贸易中介的识别方法、贸易中介影响企业贸易行为的作用机制、实证结果、企业选择贸易中介的影响因素等方面进行研究。研究发现,贸易中介的作用机制包括促进买卖方的匹配、降低贸易成本和验证产品质量; 贸易中介为企业提供了新的出口模式,帮助企业进入市场规模较小、距离较远、贸易成本较高的目的国,对企业的出口产生积极的影响,同时对企业进口国外投入品、出口和生产率提升等产生影响; 在影响因素方面,规模较小、出口产品种类越多的企业面对难以进入的市场,越可能通过贸易中介出口。研究表明,为了完善贸易中介研究的理论体系和应用实践,需要加强贸易中介能否有效应对国内外政治和经济不确定性对进出口的冲击研究,拓展跨境电商与传统贸易中介关系研究,深化企业选择混合出口模式实现贸易中介出口和直接出口的优势互补研究。     

基于可变参数优化的相关证据合成方法研究

总结了相关证据合成的理论方法,分析了已有合成方法的不足,对相关证据的相关焦元 的分布情况进行了分析,提出一种面向问题的基于可变参数的相关证据的合成方法. 方法只对 相关焦元的基本可信数进行修正,克服了对相关证据所有焦元进行修正的弱点,使修正的对象 更加合理,修正系数可用基于学习的寻优方法得到. 在相关证据的相关焦元的基本可信数未知 的情况下也可进行相关证据的合成. 计算结果表明该方法对合成的结果有明显的改进     

基于向量夹角余弦的组合预测模型的性质研究

基于向量夹角余弦的组合预测是一种相关性的组合预测模型,它是研究组合预测方法的一个新途经.针对基于向量夹角余弦准则下组合预测模型,研究它的基本结构特征.首先提出新的优性组合预测、预测方法优超、冗余度等概念.然后探讨了非劣性组合预测、优性组合预测以及冗余预测方法的存在性,并给出冗余信息的判定定理.最后进行实例分析,表明该方法有较大的实际应用价值.     

Multiscale Combined Forecast of Carbon PriceBased on Mixed Structure Data

Accurate forecast of the carbon trading price is of great significance in promoting the scientific and rational development of carbon trading market. Therefore, this paper proposes a multi-scale combined forecasting method for carbon price based on mixed structure data. First, the Google Index is used to extract the unstructured data related to the carbon price.The dimensions of unstructured data are reduced based on principal component analysis. Then, EMD is employedto the structured data,unstructured data and the carbon trading price to obtain different IMFs, which are reconstructed by the Fine-to-Coarse technique to get low, high frequency sequence and trend sequence. Furthermore, the three items are predicted respectively by using ARIMA, PLS and neural networks according to the features of each scale in time series. Finally, the forecasting results are summed to get the carbon price forecast sequence. The proposed method is used to forecast carbon price in EU. The empirical results show that the prediction accuracy of the model is higher than that of the single prediction method and the prediction method that time series aren’t decomposed by EMD, which is of great applicability.     

儒家“义—利”价值结构与西方“财富”价值结构比较研究简

通过中国儒家和西方经济价值结构的比较研究，发现儒家以“义一利”为价值结构模型，西方以“财富”为价值结构模型。儒家价值结构的基本特征是“义体利用”，表现方式是：强国的道义在于顺天时、尽地利、忠人和；安国的道义在于民朴民富；治国的道义在于蓄储俭用。西方价值结构的基本特征是“利体义用”，表现方式是：鼓励获取财富、财富规则和财富责任。儒家“义一利”价值结构与西方“财富”价值结构是两种不同的价值评判话语体系，在中国现代“义利共体”的价值结构建构中，儒家价值结构提供着人文精神基础，西方价值结构提供着物质文明建设可资借鉴的经验。     

Dependency and truncated forms of combinations in multivariate combination-based permutation tests and ordered categorical variables

ABSTRACT

Quite an important problem usually occurs in several multi-dimensional hypotheses testing problems when variables are correlated. In this framework the non-parametric combination (NPC) of a finite number of dependent permutation tests is suitable to cover almost all real situations of practical interest since the dependence relations among partial tests are implicitly captured by the combining procedure itself without the need to specify them [Pesarin F, Salmaso L. Permutation tests for complex data: theory, applications and software. Chichester: Wiley; 2010a]. An open problem related to NPC-based tests is the impact of the dependency structure on combined tests, especially in the presence of categorical variables. This paper’s goal is firstly to investigate the impact of the dependency structure on the possible significance of combined tests in cases of ordered categorical responses using Monte Carlo simulations, then to propose some specific procedures aimed at improving the power of multivariate combination-based permutation tests. The results show that an increasing level of correlation/association among responses negatively affects the power of combination-based multivariate permutation tests. The application of special forms of combination functions based on the truncated product method [Zaykin DV, Zhivotovsky LA, Westfall PH, Weir BS. Truncated product method for combining p-values. Genet Epidemiol. 2002;22:170–185; Dudbridge F, Koeleman BPC. Rank truncated product of p-values, with application to genomewide association scans. Genet Epidemiol. 2003;25:360–366] or on Liptak combination allowed us, using Monte Carlo simulations, to demonstrate the possibility of mitigating the negative effect on power of combination-based multivariate permutation tests produced by an increasing level of correlation/association among responses.     

系列性权利组合:有限责任公司股东优先购买权性质新探

股东优先购买权体现出有限责任公司人合性与资合性之间的冲突。中国对于股东优先购买权的法律规范存在缺陷,其根本原因在于缺乏一套体系性的股东优先购买权理论。股东优先购买权本质上是系列性权利组合,而非单一的权利,具体包括资格维持请求权、告知请求权、强制缔约权和优先受领权。股东于其取得股东身份时取得优先购买权,并于此时得以行使。至于优先购买权的行使期限,则不宜做过多理论上的探讨,而应当交由立法者根据本国国情加以规定。     

Treatment Evaluation in the Presence of Sample Selection

Sample selection and attrition are inherent in a range of treatment evaluation problems such as the estimation of the returns to schooling or training. Conventional estimators tackling selection bias typically rely on restrictive functional form assumptions that are unlikely to hold in reality. This paper shows identification of average and quantile treatment effects in the presence of the double selection problem into (i) a selective subpopulation (e.g., working—selection on unobservables) and (ii) a binary treatment (e.g., training—selection on observables) based on weighting observations by the inverse of a nested propensity score that characterizes either selection probability. Weighting estimators based on parametric propensity score models are applied to female labor market data to estimate the returns to education.     

Analysis of dependently truncated data in Cox framework

Truncation is a known feature of bone marrow transplant (BMT) registry data, for which the survival time of a leukemia patient is left truncated by the waiting time to transplant. It was recently noted that a longer waiting time was linked to poorer survival. A straightforward solution is a Cox model on the survival time with the waiting time as both truncation variable and covariate. The Cox model should also include other recognized risk factors as covariates. In this article, we focus on estimating the distribution function of waiting time and the probability of selection under the aforementioned Cox model.     

Working and disability expectancies at older ages: The role of childhood circumstances and education

The ability to work at older ages depends on health and education. Both accumulate starting very early in life. We assess how childhood disadvantages combine with education to affect working and health trajectories. Applying multistate period life tables to data from the Health and Retirement Study (HRS) for the period 2008–2014, we estimate how the residual life expectancy at age 50 is distributed in number of years of work and disability, by number of childhood disadvantages, gender, and race/ethnicity. Our findings indicate that number of childhood disadvantages is negatively associated with work and positively with disability, irrespective of gender and race/ethnicity. Childhood disadvantages intersect with low education resulting in shorter lives, and redistributing life years from work to disability. Among the highly educated, health and work differences between groups of childhood disadvantage are small. Combining multistate models and inverse probability weighting, we show that the return of high education is greater among the most disadvantaged.