Scheduling Updates of Probabilistic Risk Assessments: The Arkansas Nuclear One-Unit 1 Experience

This paper presents the results of a study that identified how often a probabilistic risk assessment (PRA)should be updated to accommodate the changes that take place at nuclear power plants. Based on a 7-year analysis of design and procedural changes at one plant, we consider 5 years to be the maximum interval for updating PRAs. This conclusion is preliminary because it is based on the review of changes that occurred at a single plant, and it addresses only PRAs that involve a Level 1 analysis (i.e., a PRA including calculation of core damage frequency only). Nevertheless, this conclusion indicates that maintaining a useful PRA requires periodic updating efforts. However, the need for this periodic update stems only partly from the number of changes that can be expected to take place at nuclear power plants–changes that individually have only a moderate to minor impact on the PRA, but whose combined impact is substantial and necessitates a PRA update. Additionally, a comparison of two generations of PRAs performed about 5 years apart indicates that PRAs must be periodically updated to reflect the evolution of PRA methods. The most desirable updating interval depends on these two technical considerations as well as the cost of updating the PRA. (Cost considerations, however, were beyond the scope of this study.)     

Pharmacovigilance in Clinical Trials: Current Practice and Challenges

In view of the MENA increasing participation in multinational trials and the increasing number of national/regional trials, this article explores potential areas of pharmacovigilance, requiring reform and provides recommendations for building a robust safety reporting system. Regulatory silence on expedited reporting requirements creates confusion for local sites that are part of multinational trials. Not allowing waiver for serious adverse events that are protocol specified or are study endpoints, along with lack of emphasis on causality as reporting criteria, adds substantial burden of uninformative cases for regulatory review. Despite global focus on Development Safety Update Report, local regulators are not yet insistent on real-time update of a drug’s cumulative safety profile. Issues like reporting requirements for generic trials, pregnancy reporting and lenient timeline for death/life-threatening events need attention. Finally, the need to formulate an all-encompassing local pharmacovigilance guideline, in sync with global practice cannot be overemphasized.     

Visualization for Large‐scale Gaussian Updates

In geostatistics and also in other applications in science and engineering, it is now common to perform updates on Gaussian process models with many thousands or even millions of components. These large‐scale inferences involve modelling, representational and computational challenges. We describe a visualization tool for large‐scale Gaussian updates, the ‘medal plot’. The medal plot shows the updated uncertainty at each observation location and also summarizes the sharing of information across observations, as a proxy for the sharing of information across the state vector (or latent process). As such, it reflects characteristics of both the observations and the statistical model. We illustrate with an application to assess mass trends in the Antarctic Ice Sheet, for which there are strong constraints from the observations and the physics.     

西部地区旅游产业转型升级中的科技支撑——以云南省为例

科技推动旅游产业的发展,旅游转型升级需要强化科技支撑。西部地区经济相对落后,创新能力较低,旅游业科技应用与研发水平不高,旅游科技发展亟需创新思路和工作方法,应以技术引进为基础,以技术扩散为重点,以技术创新为辅助,重点加强技术引进和扩散,大力推进模仿创新,积极培育自主创新。现阶段应制定激励政策,引导科技、教育、研发机构、行业协会形成合力,发展技术市场和中介组织,培育旅游科技应用与创新示范企业,推进智慧景区、智能酒店、数字化旅游城市试点建设。     

基于滑动窗口的自适应网页预测模型

PPM模型广泛应用于Web预取技术,但大多数的PPM模型不具有自适应性,不能反映用户浏览模式的改变。通过对标准PPM模型的扩展,提出基于滑动窗口的自适应网页预测模型。该模型仅保留处于滑动窗口之内的最近访问序列,从而反映用户兴趣的变化,同时利用非压缩后缀树增量式添加新的用户请求和删除过时的浏览信息,以提高更新速度。实验表明,该模型能更准确地描述用户在Web上的浏览特征,在预取性能上明显地优于以往的模型。     

编辑学理论研究前沿闪亮的思想结晶——论《编辑学新论》之"新"

《编辑学新论》之“新”主要体现为三个不同的创新路向:从编辑学研究的前沿考察问题,且紧密结合当前编辑出版现代化过程中的重大变化,具有立意和命题的双重时新性;根据编辑活动的特点和规律,注入新的思维因子,对既定观念、结论等进行修正和完善,更新编辑学理论体系和观点;站在编辑学理论建设的战略高度考察问题,在研究的切入点和以此为基础的一系列新思想、新看法上具有良好的创新性。     

基于自适应迭代更新的函数型数据聚类方法研究

函数型数据的稀疏性和无穷维特性使得传统聚类分析失效。针对此问题,本文在界定函数型数据概念与内涵的基础上提出了一种自适应迭代更新聚类分析。首先,基于数据参数信息实现无穷维函数空间向有限维多元空间的过渡;在此基础上,依据变量信息含量的差异构建了自适应赋权聚类统计量,并依此为函数型数据的相似性测度进行初始类别划分;进一步地,在给定阈值限制下,对所有函数的初始类别归属进行自适应迭代更新,将收敛的优化结果作为最终的类别划分。随机模拟和实证检验表明,与现有的同类函数型聚类分析相比,文中方法的分类正确率显著提高,体现了新方法的相对优良性和实际问题应用中的有效性。     

A Supply Chain with a Service Requirement for Each Market Signal

We study a single‐period two‐stage service‐constrained supply chain with an information update. The buyer has two procurement opportunities with the second one after observing a market signal, which updates the demand forecast. He also commits to a service level after observing the market signal. We derive his optimal ordering decisions and show that the critical market signal, the optimal first‐stage order quantity, and the optimal expected profit are monotone with respect to the target service level. We also discuss the impact of the forecast quality on the optimal decisions. We show that the optimal first‐stage order quantity may not be monotone with respect to information accuracy, as is in the case without the service constraint. In addition, we extend our analysis to the situation when an order cancellation is allowed upon the observation of the market signal. We also compare the results obtained for the problems with and without an order cancelation. Finally, we discuss the supply chain coordination issue and find that a buyback contract can also coordinate the supply chain in the presence of the service constraint.     

共生建构和谐:新农村建设中传统聚落的保护与更新——以辽宁绥中长城聚落小河口为例

当前,传统聚落发展与环境保护矛盾日益突出,在建设社会主义新农村中如何建立传统聚落可持续发展机制,形成保护与更新的有机结合显得非常重要。在调查辽宁长城沿线聚落的基础上,针对小河口历史人文与自然景观保护现状,从文化生态学、景观学、建筑学对聚落沿革、形成机制、景观价值和建筑特色进行分析,并结合具体保护更新实践,提出传统聚落保护更新的共生理念和以整体协调、聚集与分散相结合为原则对聚落资源进行保护利用的具体措施。