Probabilistic Analysis of Dam Accidents Worldwide: Risk Assessment for Dams of Different Purposes in OECD and Non-OECD Countries with Focus on Time Trend Analysis

This study presents probabilistic analysis of dam accidents worldwide in the period 1911–2016. The accidents are classified by the dam purpose and by the country cluster, where they occurred, distinguishing between the countries of the Organization for Economic Cooperation and Development (OECD) and nonmember countries (non-OECD without China). A Bayesian hierarchical approach is used to model distributions of frequency and severity for accidents. This approach treats accident data as a multilevel system with subsets sharing specific characteristics. To model accident probabilities for a particular dam characteristic, this approach samples data from the entire data set, borrowing the strength across data set and enabling to model distributions even for subsets with scarce data. The modelled frequencies and severities are combined in frequency-consequence curves, showing that accidents for all dam purposes are more frequent in non-OECD (without China) and their maximum consequences are larger than in OECD countries. Multipurpose dams also have higher frequencies and maximum consequences than single-purpose dams. In addition, the developed methodology explicitly models time dependence to identify trends in accident frequencies over the analyzed period. Downward trends are found for almost all dam purposes confirming that technological development and implementation of safety measures are likely to have a positive impact on dam safety. The results of the analysis provide insights for dam risk management and decision-making processes by identifying key risk factors related to country groups and dam purposes as well as changes over time.     

How does BREXIT affect production patterns of multinational enterprises?

This paper explores how the British exit from the European Union (EU) potentially affects the United Kingdom (UK) economy and the production patterns of multinational enterprises that choose the UK as either a destination market or a gateway to the EU market. Utilizing an extended version of the knowledge-capital model, which includes six types of firms and four countries grouped into market and non-market, simulation analysis reveals that efforts to enhance attractiveness of the UK as a destination market to increase horizontal-type inward foreign direct investment would be a solution to cover losses from reduction in the number of export-platforms.     

Does the twin deficit hypothesis hold in the OECD countries under different real interest rate regimes?

This paper explores the validity of the twin deficit hypothesis in selected 25 OECD countries with annual data for 2005–2016 by considering different real interest rate regimes. A non-dynamic panel threshold model, introduced by Hansen (1999), is employed. The novelty of the empirical findings from the present study is that there exists a non-linear relationship between the budget deficit and the trade balance, which is driven by a critical threshold level in the real interest rates. The findings suggest that twin deficit hypothesis holds only under the low real interest rate regime, that is, rises in budget deficits lead to deteriorations in the trade balance when the real interest rate is below the threshold level. When the high real interest rate (i.e. above-the-threshold) regime is concerned, increasing budget deficits give rise to improvements in the trade balance, a finding consistent with the twin divergence hypothesis. Thus, the effect on the trade balance of an expansionary fiscal policy that worsens the budget balance reverses substantially depending on the threshold level of the real interest rates. The major policy implication of this paper is that the policy makers in the selected OECD countries should pay a greater attention to fiscal discipline in order to prevent the trade balance from worsening, because the majority of the countries fall into the low real interest rate regime over the recent years of the sample period (i.e. between 2010 and 2016).     

Heterogeneous treatment effects on Children's cognitive/non-cognitive skills: A reevaluation of an influential early childhood intervention

The 1962–67 High/Scope Perry Preschool Program, a well-known experimental early childhood intervention study that provided quality preschool education to disadvantaged children, has been shown to have had positive impacts on early child development and on a variety of adulthood outcomes. However, most previous analyses have only examined average treatment effects across all program participants without exploring possible effect heterogeneity by children's background characteristics. We investigated this question by first using the 1964–65 Current Population Survey data in combination with the Perry data to construct a scale of child socioeconomic status based on the estimated propensity for inclusion in the Perry program, then analyzing effect heterogeneity within the Perry sample by strata of our socioeconomic scale. We found that the treatment effects of enrollment in the Perry preschool on cognitive and non-cognitive skills were much larger and more persistent among the most disadvantaged children than among others in the Perry program. Furthermore, among the most disadvantaged children, the treatment (i.e., preschool enrollment) affects later outcomes through a reinforcement mechanism of skill development (i.e., early cognitive gain leads to a non-cognitive gain, which in turn leads to later cognitive gain) and a sequential improvement of cognitive skills over time. These findings have important implications for the evaluation of policy interventions in early child development using experimental data.     

Water cycle algorithm for solving the reliability-redundancy allocation problem with a choice of redundancy strategies

Abstract

This paper proposes a new mathematical model for the reliability-redundancy allocation problem (RRAP) with a choice of redundancy strategies. To maximize the reliability of a system, this model chooses the best redundancy strategy from among both active and standby ones for each subsystem. For those with a standby strategy, a continuous time Markov chain model is used to calculate the exact reliability values. In order to solve the proposed mixed-integer non-linear programing model, a powerful evolutionary algorithm, called water cycle algorithm (WCA), is developed and implemented on three famous benchmark problems. Finally, the results of different benchmark problems are compared with those previously reported to show the superiority of the proposed model and the efficiency of WCA.     

西方残障身份发展理论述评及本土化思考

积极的残障身份认同对残障者本身具有重要意义,残障身份发展是残障者实现身份认同的路径,理解残障身份发展的过程也可以让残疾人工作者更好地为残障者提供教育、康复等相关服务。本文通过梳理较为典型的西方残障身份发展理论,结合国内残障身份相关研究及本土社会文化背景展开讨论。文章认为,在西方残障身份发展理论框架下,残障者形成积极身份认同的关键在于认同并融入一套在残障社区内共享的残障文化,而在我国社会文化背景下,目前并没有一套成体系的残障文化,残障者也难以体会残障的文化身份感,国内残障者的身份认同缺少本土残障文化依靠。     

Adaptive and repeated cumulative meta‐analyses of safety data during a new drug development process

During a new drug development process, it is desirable to timely detect potential safety signals. For this purpose, repeated meta‐analyses may be performed sequentially on accumulating safety data. Moreover, if the amount of safety data from the originally planned program is not enough to ensure adequate power to test a specific hypothesis (e.g., the noninferiority hypothesis of an event of interest), the total sample size may be increased by adding new studies to the program. Without appropriate adjustment, it is well known that the type I error rate will be inflated because of repeated analyses and sample size adjustment. In this paper, we discuss potential issues associated with adaptive and repeated cumulative meta‐analyses of safety data conducted during a drug development process. We consider both frequentist and Bayesian approaches. A new drug development example is used to demonstrate the application of the methods. Copyright © 2015 John Wiley & Sons, Ltd.     

Asian children’s verbal development: A comparison of the United States and Australia

Using longitudinal cohort studies from Australia and the United States, we assess the pervasiveness of the Asian academic advantage by documenting White-Asian differences in verbal development from early to middle childhood. In the United States, Asian children begin school with higher verbal scores than Whites, but their advantage erodes over time. The initial verbal advantage of Asian American children is partly due to their parent’s socioeconomic advantage and would have been larger had it not been for their mother’s English deficiency. In Australia, Asian children have lower verbal scores than Whites at age 4, but their scores grow a faster rate and converge towards those of Whites by age 8. The initial verbal disadvantage of Asian Australian children is partly due to their mother’s English deficiency and would have been larger had it not been for their Asian parent’s educational advantage. Asian Australian children’s verbal scores grow at a faster pace, in part, because of their parent’s educational advantage.