Haitao Zheng

Compared to metallic materials, composites exhibit greater uncertainty, with some input variables characterized by limited and sparse data. Traditional nonprobabilistic methods provide only a qualitative range for uncertainty parameters, which is insufficient for quantifying credibility effectively and consequently increases the conservativeness of structural reliability analysis. To quantify uncertainty parameters in composites, a nonprobabilistic interval approach is employed to address the challenges posed by various failure modes and limited sample sizes. Based on Bayesian theory, a truncated normal distribution is utilized as the prior for the interval radius, with new sample points introduced to update this radius. The MCMC method is employed to numerically solve for the posterior distribution, thereby establishing a connection between the nonprobabilistic quantification sets and the credible levels. A nonprobabilistic credible Bayesian reliability model for composites is developed by integrating the Hashin failure criterion with Taylor series expansion for uncertainty propagation analysis. The effectiveness and feasibility of the proposed model are demonstrated through two relevant numerical examples.

The causal effect of public pensions on the mental wellbeing of the elderly in lower and middle-income countries deserves further investigation. This paper first constructed a theoretical framework for the impact of New Rural Society Pension Insurance pensions in China on the mental wellbeing of the rural elderly, and described potential channels through which pension income may affect mental wellbeing. We then used the fixed effect model and the instrument variable approach to estimate the casual effects of pension income on the mental wellbeing of the rural elderly. The results reveal that pension income improves mental wellbeing by relieving depression of the rural elderly; however, the beneficial effects of pension income are very limited. Pension income has no beneficial effects on the mental health of the rural elderly in the east region, whereas it slightly relieves depression of those in the middle and west regions. We also found that pension income produces small improvements in the mental health of older females, elderly persons living independently, and those with relatively poor economic conditions.

Econometricians construct panel logit-based early warning systems (EWSs) as the primary predictive tool to prevent incoming systemic banking crises. Considering the actual scenario of systemic banking crises, we argue that changes in economic indicators under the crisis may impact the information extraction of EWSs based on logistic regression. According to the potential limitations of the conventional EWS and properties of the machine learning algorithm, we assume that an ‘experts voting EWS’ framework can better fit characteristics of data of systemic banking crisis. Indeed, among other machine learning classifiers tested in this paper, random forest classifier simulating experts voting process is the most efficient classifier showing relatively high generalization above 80% area under the receiver operating characteristic curve on constructing the EWS. In contrast to the conventional system, an image of evidence shows that the experts voting EWS synthesizing multivariate information may be suitable for providing systemic banking systemic crises alerts in varied contexts.

The percentage of institutional ownership in China has increased gradually. Does this characteristic of Chinese institutional investors affect their participation in corporate governance, which in turn, affects corporate tax avoidance activities? We take 1108 listed Chinese companies from 2009 to 2017 to study this issue. The paper uses average daily total market capitalization as an instrumental variable to test the endogeneity problems. We run a quantile regression (QR) at the median level as robustness testing to overcome the fat tail of financial data. Then, the shareholding ratio of majority shareholders is introduced to verify that ownership concentration is one of the mechanisms through which institutional shareholders influence corporate tax avoidance decisions. The findings are as follows: The proportion of institutional investors’ shareholdings is positively related to the degree of enterprise tax avoidance. The increase in institutional investors’ shareholdings is likely to promote corporate tax avoidance. When the level of ownership concentration is low, the increase in institutional ownership can play a greater role in promoting tax avoidance.

The claim process in an insurance risk model with uncertainty is traditionally described by an uncertain renewal reward process. However, the claim process actually includes two processes, which are called the report process and the payment process, respectively. An alternative way is to describe the claim process by an uncertain alternating renewal reward process. Therefore, this paper proposes an insurance risk model under uncertain measure in which the claim process is supposed to be an alternating renewal reward process and the premium process is regarded as a renewal reward process. Then, the paper also gives the inverse uncertainty distribution of the insurance risk process. The expression of ruin index and the uncertainty distribution of the ruin time are derived which both have explicit expressions based on given uncertainty distributions. Finally, several examples are provided to illustrate the modeling ideas.

With the relatively fixed retirement age, the dramatic increase in life expectancy and the sharp decline in fertility have caused a serious aging problem and an unsustainable pension crisis. It is therefore necessary to design flexible retirement benefits rules that consider life expectancy. By introducing the lifetime utility optimization model, the closed-form solution for the flexible retirement age is obtained. Pension benefits incentive strategies are constructed to encourage contributors to choose a retirement age that is beneficial toward narrowing the pension gap. The empirical studies show that China will face a serious pension gap in the future if the current statutory retirement age is not adjusted. If the retirement age is delayed according to life expectancy, the future pension gap will be greatly reduced.