Improved Transferability of Data‐Driven Damage Models Through Sample Selection Bias Correction

Damage models for natural hazards are used for decision making on reducing and transferring risk. The damage estimates from these models depend on many variables and their complex sometimes nonlinear relationships with the damage. In recent years, data‐driven modeling techniques have been used to capture those relationships. The available data to build such models are often limited. Therefore, in practice it is usually necessary to transfer models to a different context. In this article, we show that this implies the samples used to build the model are often not fully representative for the situation where they need to be applied on, which leads to a “sample selection bias.” In this article, we enhance data‐driven damage models by applying methods, not previously applied to damage modeling, to correct for this bias before the machine learning (ML) models are trained. We demonstrate this with case studies on flooding in Europe, and typhoon wind damage in the Philippines. Two sample selection bias correction methods from the ML literature are applied and one of these methods is also adjusted to our problem. These three methods are combined with stochastic generation of synthetic damage data. We demonstrate that for both case studies, the sample selection bias correction techniques reduce model errors, especially for the mean bias error this reduction can be larger than 30%. The novel combination with stochastic data generation seems to enhance these techniques. This shows that sample selection bias correction methods are beneficial for damage model transfer.     

网络服务提供者著作权侵权中的双重注意义务

《民法典》侵权责任编对原有通知删除规则进行了科学修正，但事前保护缺位与事后救济程序失范的问题仍然存在。随着网络服务提供者完成角色转型和技术升级，其作为网络侵权风险的控制者和参与者，有必要且有能力承担未通知阶段的主动预防义务和已通知阶段的证明材料审查义务，以弥补著作权保护和用户利益保护的漏洞。双重注意义务应分别与网络服务提供者对侵权危险的预期和控制能力以及材料审查能力相适应。未通知阶段之注意义务以技术措施为主要履行方式，其注意标准的认定应综合考量技术水平、服务类型、内容介入程度、是否直接获取收益等要素，未尽该注意义务仅为过错认定的考量因素而非唯一标准，并不必然导致侵权责任。已通知阶段之注意义务仅限于对提交的证明材料进行形式审查和有限的实质审查，尽到此注意义务的，可以免于承担侵权责任。     

The value of being precise

This study investigates how individuals assess imprecise information. We focus on two essential dimensions of decision under uncertainty, outcomes and probabilities, and their respective precision. We believe the precision of information is highly relevant in the investment setting, as reflected in the well-known “home (familiarity) bias”, and the outcome and probability dimensions, separately or jointly, may affect investors’ knowledge of uncertainty and perceived risk of the investment options, and subsequently affect investors’ choices. To test this conjecture, we conducted three experiments. Our results show that 1) participants demonstrate a pattern of preference for precision and aversion of extreme vagueness and associate vagueness with higher perceived risk and lower investment (experiments one and two); 2) participants prefer vague outcome information to vague probability information (experiment two); 3) familiarity indeed positively affects the precision of estimated values, but this association is stronger for the outcome dimension than for probabilities (experiment three). Our results confirm that precision in information, especially in the outcome dimension has an impact on investors’ resource allocation choices.     

Changes in work and care trajectories during the transition to motherhood

In most mid- and high-income countries, there have been significant demographic, structural, and cultural changes in the past decades. However, we know little about how these changes have shaped women's work patterns during a key life stage: the transition to motherhood. Using longitudinal data from Chile, covering over 30 years of employment histories and three periods of first births (1980–2010), I conduct sequence analysis to identify women's work-care trajectories during an eight-year period of the transition to motherhood. Over time, I find that continuous care work at home has declined, for which education plays a key role, while the chances of working continuously have not changed over time. Instead, I find an increasing trend of unsteady paths that combine paid work with either caretaking or unemployment. I discuss how these changes, as well as their association with education, have important implications for both gender and social inequality.     

Price bias and common practice in option pricing

Generally, the semiclosed-form option pricing formula for complex financial models depends on unobservable factors such as stochastic volatility and jump intensity. A popular practice is to use an estimate of these latent factors to compute the option price. However, in many situations this plug-and-play approximation does not yield the appropriate price. This article examines this bias and quantifies its impacts. We decompose the bias into terms that are related to the bias on the unobservable factors and to the precision of their point estimators. The approximated price is found to be highly biased when only the history of the stock price is used to recover the latent states. This bias is corrected when option prices are added to the sample used to recover the states' best estimate. We also show numerically that such a bias is propagated on calibrated parameters, leading to erroneous values. The Canadian Journal of Statistics 48: 8–35; 2020 © 2019 Statistical Society of Canada     

Visualization of generalized mean estimators using auxiliary information in survey sampling

Abstract

The mean estimators with ratio depend on multiple auxiliary variables and unknown parameters in a finite population setting. We propose a new generalized approach with matrices for modeling the mutivariate mean estimators with two auxiliary variables. Our approach brings naturally a graphical analysis for comparing mean estimators.     

市场分割、政企关系与异地市场拓展

中国的市场仍旧存在某种程度的分割，如何突破这种市场分割到异地拓展市场是企业要考虑的现实问题。以前的研究主要是从省级层面或国家层面进行宏观分析。文章创新地从政企关系视角入手来考察市场分割情形下微观层面的企业异地市场拓展，也是首先把市场分割（和异地市场）分为省内（本市外）市场、省外市场和海外市场三个不同层面来研究的论文。用世界银行的调查数据从微观企业个体层面检验了企业异地市场拓展的可能。实证研究结果发现，市场分割确实阻碍了企业异地市场拓展，但这仅限于省内市场而不是省外市场。此外，市场分割是有方向性的，从地方保护主义严重的市场里走出来的企业更容易拓展异地市场，但此结论仅适用于国内市场拓展而不适用于海外市场拓展。良好的政企关系是有利于企业异地市场拓展的，但仅限于省外市场，对省内市场以及海外市场是无效的。文章解释了其中的原因，并分析了对于企业实践的启示。     

金诗学唐的历程

金代诗歌在受苏轼等宋代诗人的影响之外 ,也受到唐诗的浸润。本文依据金诗发展变化的自身情况 ,考察了金诗学唐的历程。文中将金诗学唐分为金初“借才异代”时期、“国朝文派”时期、金代后期等三个阶段 ,做了比较详细的论述 ,从一个方面展示了金诗发展的轨迹 ,揭示了金诗的某些重要特点 ,对于我们深入地认识金诗是有裨益的     

Stigma, HIV/AIDS and prevention of mother-to-child transmission in Zambia

This report evaluates the extent of perceived and enacted HIV/AIDS-related stigma in a rural setting in Zambia. Stigmatisation is abundant, ranging from subtle actions to the most extreme degradation, rejection and abandonment. Women with HIV and pregnant women assumed to be HIV positive are repeatedly subjected to extensive forms of stigma, particularly once they become sick or if their child dies. Despite increasing access to prevention of mother to child transmission initiatives, including anti-retroviral drugs, the perceived disincentives of HIV testing, particularly for women, largely outweigh the potential gains from available treatments. HIV/AIDS related stigma drives the epidemic underground and is one of the main reasons that people do not wish to know their HIV status. Unless efforts to reduce stigma are, as one peer educator put it, “written in large letters in any HIV/AIDS campaign rather than small”, stigma will remain a major barrier to curbing the HIV/AIDS pandemic.