On conditional risk estimation considering model risk

Usually, parametric procedures used for conditional variance modelling are associated with model risk. Model risk may affect the volatility and conditional value at risk estimation process either due to estimation or misspecification risks. Hence, non-parametric artificial intelligence models can be considered as alternative models given that they do not rely on an explicit form of the volatility. In this paper, we consider the least-squares support vector regression (LS-SVR), weighted LS-SVR and Fixed size LS-SVR models in order to handle the problem of conditional risk estimation taking into account issues of model risk. A simulation study and a real application show the performance of proposed volatility and VaR models.     

Combining Inverse Probability Weighting and Multiple Imputation to Improve Robustness of Estimation

Inverse probability weighting (IPW) and multiple imputation are two widely adopted approaches dealing with missing data. The former models the selection probability, and the latter models data distribution. Consistent estimation requires correct specification of corresponding models. Although the augmented IPW method provides an extra layer of protection on consistency, it is usually not sufficient in practice as the true data‐generating process is unknown. This paper proposes a method combining the two approaches in the same spirit of calibration in sampling survey literature. Multiple models for both the selection probability and data distribution can be simultaneously accounted for, and the resulting estimator is consistent if any model is correctly specified. The proposed method is within the framework of estimating equations and is general enough to cover regression analysis with missing outcomes and/or missing covariates. Results on both theoretical and numerical investigation are provided.     

文化意识与译者中间物本质——也论鲁迅"宁信而不顺"的翻译原则

鲁迅的"宁信而不顺"的翻译主张不仅仅是其翻译原则,更是其文化意识的一个表现.具体而言,是其文化自省意识的产物,及其拿来主义文化策略的体现.其中所蕴含的对译者中间物本质的理解源于他的中间物意识,深刻地揭示了翻译活动中译者的主体性价值.     

魏晋六朝“自然”论文学观的确立——论《文心雕龙》的“文道自然”观

以"自然"论文学,汉朝<淮南子>已有记载,但只言片语,语焉不详,直到魏晋鸿篇<文心雕龙>才有了真正意义上的"自然"论文学观.刘勰以"自然之道"来阐释文学创作的根本原则,从哲学本体论高度论证"文"之产生与存在的必然性、"文"与"质"的本质统一关系,并以此为核心探讨了文学创作之发生、文学风格之生成、创作自由之实现等一系列重要问题,建立了相当系统化的"文道自然"观.     

理性极限及其突破断想

思维具有历史的特征.而理性思维只是人类思维的一个阶段.因此,理性思维及与之相对应的理性哲学都无法超越自身的历史局限.理性哲学缺失与当下生活的对应的根本原因就在于理性极限.而理性的偏见与虚妄的悲剧价值预设正是这种极限的表现.打破理性极限的前提是将理性还原于历史中并具体列出突破理性哲学的叙述方案.     

词式书写对小学生阅读效率影响的实验分析

本实验旨在通过测试三至六年级小学生对汉字词式书写文本与传统的字式书写文本的阅读速度和阅读理解正确率,来评价汉字词式书写对小学生阅读效率的影响.实验结果表明:与阅读字式书写文本相比,第一次阅读词式书写文本即可不同程度地提高各年级小学生的中文阅读效率.     

董小宛入宫说始于何时——兼略探吴梅村《清凉山赞佛诗》的创作意图

董小宛入宫说始于清末之见不确,仅仅一部《红楼梦》就能证明早在乾隆年间即存在董小宛入宫说,而导致此说产生、传播的,则当是对顺治末年吴梅村《清凉山赞佛诗》的误解。     

Measures of individual risk attitudes and portfolio choice: Evidence from pension participants

We use a large non-student sample to test how distinct measures of risk-attitudes relate to each other, to demographic characteristics and to real-life risk taking in the financial domain. These measures, namely the Bomb Risk Elicitation Task (BRET), self-reported willingness to take risks in general, the choice in a hypothetical lottery, the score in the Domain Specific Risk-Taking (DOSPERT) scale, appear to be positively correlated and exhibit a certain degree of consistency. Furthermore, a subset of these measures is driven by similar demographic characteristics as such that males are more risk seeking and risk-aversion increases with age. Using extensive data on the retirement portfolios of the participants during the years 2008–2014, we find that all of these measures are positively correlated with the riskiness of individual portfolios. The self-reported willingness to take risks in general appears to be the most relevant measure in predicting actual risk-taking behavior.     

On inference for Kendall's τ within a longitudinal data setting

Kendall's τ is a non-parametric measure of correlation based on ranks and is used in a wide range of research disciplines. Although methods are available for making inference about Kendall's τ, none has been extended to modeling multiple Kendall's τs arising in longitudinal data analysis. Compounding this problem is the pervasive issue of missing data in such study designs. In this article, we develop a novel approach to provide inference about Kendall's τ within a longitudinal study setting under both complete and missing data. The proposed approach is illustrated with simulated data and applied to an HIV prevention study.