A Framework to Understand Extreme Space Weather Event Probability

An extreme space weather event has the potential to disrupt or damage infrastructure systems and technologies that many societies rely on for economic and social well‐being. Space weather events occur regularly, but extreme events are less frequent, with a small number of historical examples over the last 160 years. During the past decade, published works have (1) examined the physical characteristics of the extreme historical events and (2) discussed the probability or return rate of select extreme geomagnetic disturbances, including the 1859 Carrington event. Here we present initial findings on a unified framework approach to visualize space weather event probability, using a Bayesian model average, in the context of historical extreme events. We present disturbance storm time (Dst ) probability (a proxy for geomagnetic disturbance intensity) across multiple return periods and discuss parameters of interest to policymakers and planners in the context of past extreme space weather events. We discuss the current state of these analyses, their utility to policymakers and planners, the current limitations when compared to other hazards, and several gaps that need to be filled to enhance space weather risk assessments.     

基于数量柔性契约的双源应急物资采购定价模型

针对灾害事件发生的不确定性以及灾害发生后应急物资需求量的爆发式增长，本文设计了一个政府主导的基于数量柔性契约的双源应急物资采购模型。在存在一个现货市场的情况下，政府除了常规采购外，还会与供应方签订一份数量柔性契约，用以建立政企联合储备应急物资的合作关系。通过数理推导，本文发现灾害事件发生概率，政府自身储备量，现货市场采购价格会对双方决策产生重要影响，并给出三个影响因素在满足不同条件时政企双方的最优决策，同时进一步分析了这三个因素对政府采购成本与供应方利润的影响。最后，通过数值模拟的方式对所得结论进行了验证。本文的研究为政府与企业构建联合储备应急物资的合作关系提供了指导与依据。     

Testing the gender similarities hypothesis: differences in subjective task value and motivation to transfer training

ABSTRACT

Are female and male trainees similar or different in their reaction to training programmes, specifically regarding their subjective task value and motivation to transfer? According to the gender similarities hypothesis, women and men are alike on most psychological variables. However, according to research in organizational behaviour, female and male employees differ on certain aspects, such as their job satisfaction and work identity. To test these two views on gender similarities and differences in the context of human resource development and training evaluation, the present study examined the extent to which gender moderated reactions to training. Based on the expectancy-value theory of motivation and self-determination theory, a web-based questionnaire was used to measure six training reactions: intrinsic value, attainment value, utility value, perceived relative cost, autonomous motivation to transfer, and controlled motivation to transfer. The results indicated that women and men differed in their ratings of attainment value but were similar for the remaining five reaction measures. These outcomes support the gender similarities hypothesis. The findings are discussed in terms of their theoretical implications for modelling gender effects in HRD research and their practical significance for promoting training effectiveness and transfer of training.     

Beyond tail median and conditional tail expectation: Extreme risk estimation using tail Lp-optimization

The conditional tail expectation (CTE) is an indicator of tail behavior that takes into account both the frequency and magnitude of a tail event. However, the asymptotic normality of its empirical estimator requires that the underlying distribution possess a finite variance; this can be a strong restriction in actuarial and financial applications. A valuable alternative is the median shortfall (MS), although it only gives information about the frequency of a tail event. We construct a class of tail L^p-medians encompassing the MS and CTE. For p in (1,2), a tail L^p-median depends on both the frequency and magnitude of tail events, and its empirical estimator is, within the range of the data, asymptotically normal under a condition weaker than a finite variance. We extrapolate this estimator and another technique to extreme levels using the heavy-tailed framework. The estimators are showcased on a simulation study and on real fire insurance data.     

存在议价能力和副产品协同生产的制造商最优产量决策

考虑由环保型制造商和处理厂构成的两级供应链结构，其中上游制造商进行主产品的生产，而下游处理厂通过对废料加工进行副产品的生产。基于供应链成员之间存在不同议价能力的情形，构建了上游制造商将产生的废料给下游进行处理的协同生产模式，给出了主产品的均衡产量决策和废料的最优交易价格以及制造商关于废料的最优处理策略。研究结果表明，制造商的废料处理策略取决于消费者对副产品产量的敏感程度。当消费者对副产品产量较敏感（不敏感）时，制造商会选择自己处理废料（给处理厂进行加工）。此外，随着制造商议价能力的上升，制造商的均衡利润上升，而处理厂的均衡利润下降。最后发现本文的基本结论在随机产出环境下依然稳健。     

Max‐infinitely divisible models and inference for spatial extremes

For many environmental processes, recent studies have shown that the dependence strength is decreasing when quantile levels increase. This implies that the popular max‐stable models are inadequate to capture the rate of joint tail decay, and to estimate joint extremal probabilities beyond observed levels. We here develop a more flexible modeling framework based on the class of max‐infinitely divisible processes, which extend max‐stable processes while retaining dependence properties that are natural for maxima. We propose two parametric constructions for max‐infinitely divisible models, which relax the max‐stability property but remain close to some popular max‐stable models obtained as special cases. The first model considers maxima over a finite, random number of independent observations, while the second model generalizes the spectral representation of max‐stable processes. Inference is performed using a pairwise likelihood. We illustrate the benefits of our new modeling framework on Dutch wind gust maxima calculated over different time units. Results strongly suggest that our proposed models outperform other natural models, such as the Student‐t copula process and its max‐stable limit, even for large block sizes.     

Interval estimation for conformance proportions of multiple quality characteristics

A conformance proportion is an important and useful index to assess industrial quality improvement. Statistical confidence limits for a conformance proportion are usually required not only to perform statistical significance tests, but also to provide useful information for determining practical significance. In this article, we propose approaches for constructing statistical confidence limits for a conformance proportion of multiple quality characteristics. Under the assumption that the variables of interest are distributed with a multivariate normal distribution, we develop an approach based on the concept of a fiducial generalized pivotal quantity (FGPQ). Without any distribution assumption on the variables, we apply some confidence interval construction methods for the conformance proportion by treating it as the probability of a success in a binomial distribution. The performance of the proposed methods is evaluated through detailed simulation studies. The results reveal that the simulated coverage probability (cp) for the FGPQ-based method is generally larger than the claimed value. On the other hand, one of the binomial distribution-based methods, that is, the standard method suggested in classical textbooks, appears to have smaller simulated cps than the nominal level. Two alternatives to the standard method are found to maintain their simulated cps sufficiently close to the claimed level, and hence their performances are judged to be satisfactory. In addition, three examples are given to illustrate the application of the proposed methods.     

A new financial stress index model based on support vector regression and control chart

Financial stress index (FSI) is considered to be an important risk management tool to quantify financial vulnerabilities. This paper proposes a new framework based on a hybrid classifier model that integrates rough set theory (RST), FSI, support vector regression (SVR) and a control chart to identify stressed periods. First, the RST method is applied to select variables. The outputs are used as input data for FSI–SVR computation. Empirical analysis is conducted based on monthly FSI of the Federal Reserve Bank of Saint Louis from January 1992 to June 2011. A comparison study is performed between FSI based on the principal component analysis and FSI–SVR. A control chart based on FSI–SVR and extreme value theory is proposed to identify the extremely stressed periods. Our approach identified different stressed periods including internet bubble, subprime crisis and actual financial stress episodes, along with the calmest periods, agreeing with those given by Federal Reserve System reports.     

卢梭主体性教育思想及启示

卢梭的主体性教育思想强调人的主体性，凸显了教育过程中受教育者的主体地位。反映在儿童教学中，就是教育应体现儿童的天性，要以儿童作为主体，根据儿童的特点，充分发挥主动性和创造性，引导进行自主、能动的学习。为了更好地了解卢梭的主体性教育思想，本文对其作了详细的整理和系统的阐释，在介绍理论与特征的基础上，重点论述该思想的内涵及目的，思考其对现代儿童教育的启示，以期望能丰富现有的教学理论，为儿童教育的发展提供理论和现实依据。     

关于大学生思想政治教育主体契合的思考

学习领会中共中央颁发的《关于进一步加强和改进大学生思想政治教育的意见》精神,坚持真理尺度和价值尺度相统一即美的尺度,着眼于大学生思想政治教育的主体契合问题,得出如下几点思考:一是必须把理想信念教育同大学生成长、成就、成功的内在需求契合;二是必须把爱国主义教育同大学生自尊、自强、自立的内在需求契合;三是必须把基本道德规范教育同大学生社会化、公民化、职业化的内在需求契合;四是必须把完整素质教育同大学生铸人、铸身、铸才的内在需求契合。