Experiment-dependent priors in psychology and physics

Sometimes conducting an experiment to ascertain the state of a system changes the state of the system being measured. Kahneman & Tversky modelled this effect with support theory. Quantum physics models this effect with probability amplitude mechanics. As this paper shows, probability amplitude mechanics is similar to support theory. Additionally, Viscusi's proposed generalized expected utility model has an analogy in quantum mechanics.     

材料力学课程教改研究

教育部"力学系列课程教学内容与体系改革的研究与实践"项目成果在高等院校推广以来,笔者转变教学思想,对原有普通工科高校材料力学课程教学体系进行了重新审视,制定了材料力学教改的阶段性规划,在教材选取,课堂讲授内容筛选,平时作业批改、答疑,期末考核等各方面都有步骤地进行了教改实践,以摸索出适应我院情况的教学模式.     

Fitting Hierarchical Holographic Modeling into the Theory of Scenario Structuring and a Resulting Refinement to the Quantitative Definition of Risk

A point of view is suggested from which the Hierarchical Holographic Modeling (HHM) method can be seen as one more method within the Theory of Scenario Structuring (TSS), which is that part of Quantitative Risk Assessment having to do with the task of identifying the set of risk scenarios. Seen in this way, HHM brings strongly to our attention the fact that different methods within TSS can result in different sets of risk scenarios for the same underlying problem. Although this is not a problem practically, it is a bit awkward conceptually from the standpoint of the "set of triplets" definition of risk, in which the scenario set is part of the definition. Accordingly, the present article suggests a refinement to the set of triplets definition, which removes the specific set of scenarios, found by any of the TSS methods, from the definition of risk and casts it, instead, as an approximation to the "true" set of scenarios that is native to the problem at hand and not affected by the TSS method used.     

Floods and Climate Change: Interactions and Impacts

Whether the floods experienced during the last decade in Germany and in other European countries are triggered or worsened by human activities has been the subject of a great deal of debate. Possible anthropogenic activities leading to increased flood risk include river regulation measures, intensified land use and forestry, and emissions of greenhouse gases causing a change in the global climate. This article discusses the latter by reviewing the existing knowledge on the subject. First, the relevance, capabilities, and limitations of climate models for the simulation and analysis of flood risk under aspects of the anthropogenic climate change are described. Special consideration is given here to differences between the "typical" spatial scale of climate models and hydrological flood models. Second, observations of trends in climate variables relevant for river flooding issues are summarized. Special emphasis is put on the Rhine and other German catchment areas. Third, the possibilities of modeling the different parts of the "cascade of flood risk" are summarized, introducing the special features of meteorological, hydrological, and river hydraulic models.     

多媒体教学手段在《理论力学》讲课中的应用

二十世纪后期电脑和信息技术在经济建设和科学技术的各个领域得到广泛的应用.在这样的形势下,高等学校中也面临着教育改革的迫切任务,如何在各门课程中,高质量和高效率地培养学生,已成为现实的问题.本文涉及<理论力学>课程的讲课方式的改革,介绍我们采用多媒体手段进行<理论力学>讲课的实践和体会,并提出一些有关的看法.     

利用智能主体分析"时尚"的涌现

时尚作为一种社会现象,是由个别人物的倡导和示范,先在少数人中流行,然后迅速蔓延到社会.多数人出于新奇与从众心理而仿效.对于它的研究有助于人们把握这种社会现象的产生与蔓延过程,深入认识和控制它的发展.由于它的复杂多样性,当前还缺乏对它的定量分析与研究.论文利用基于智能主体的仿真方法,分析了时尚的涌现过程.文中建立了两种模型,用于确定公众能否接受某种时尚的临界值.一种模型基于公众能获取全部信息,另一种则基于个人只能获取邻近信息.     

Use of Markov Chain Monte Carlo Analysis with a Physiologically-Based Pharmacokinetic Model of Methylmercury to Estimate Exposures in U.S. Women of Childbearing Age

A Bayesian approach, implemented using Markov Chain Monte Carlo (MCMC) analysis, was applied with a physiologically‐based pharmacokinetic (PBPK) model of methylmercury (MeHg) to evaluate the variability of MeHg exposure in women of childbearing age in the U.S. population. The analysis made use of the newly available National Health and Nutrition Survey (NHANES) blood and hair mercury concentration data for women of age 16–49 years (sample size, 1,582). Bayesian analysis was performed to estimate the population variability in MeHg exposure (daily ingestion rate) implied by the variation in blood and hair concentrations of mercury in the NHANES database. The measured variability in the NHANES blood and hair data represents the result of a process that includes interindividual variation in exposure to MeHg and interindividual variation in the pharmacokinetics (distribution, clearance) of MeHg. The PBPK model includes a number of pharmacokinetic parameters (e.g., tissue volumes, partition coefficients, rate constants for metabolism and elimination) that can vary from individual to individual within the subpopulation of interest. Using MCMC analysis, it was possible to combine prior distributions of the PBPK model parameters with the NHANES blood and hair data, as well as with kinetic data from controlled human exposures to MeHg, to derive posterior distributions that refine the estimates of both the population exposure distribution and the pharmacokinetic parameters. In general, based on the populations surveyed by NHANES, the results of the MCMC analysis indicate that a small fraction, less than 1%, of the U.S. population of women of childbearing age may have mercury exposures greater than the EPA RfD for MeHg of 0.1 μg/kgg/day, and that there are few, if any, exposures greater than the ATSDR MRL of 0.3 μgg/kgg/day. The analysis also indicates that typical exposures may be greater than previously estimated from food consumption surveys, but that the variability in exposure within the population of U.S. women of childbearing age may be less than previously assumed.     

Development of a Screening Approach to Interpret Human Biomonitoring Data on Volatile Organic Compounds: Reverse Dosimetry on Biomonitoring Data for Trichloroethylene

A screening approach is developed for volatile organic compounds (VOCs) to estimate exposures that correspond to levels measured in fluids and/or tissues in human biomonitoring studies. The approach makes use of a generic physiologically-based pharmacokinetic (PBPK) model coupled with exposure pattern characterization, Monte Carlo analysis, and quantitative structure property relationships (QSPRs). QSPRs are used for VOCs with minimal data to develop chemical-specific parameters needed for the PBPK model. The PBPK model is capable of simulating VOC kinetics following multiple routes of exposure, such as oral exposure via water ingestion and inhalation exposure during shower events. Using published human biomonitoring data of trichloroethylene (TCE), the generic model is evaluated to determine how well it estimates TCE concentrations in blood based on the known drinking water concentrations. In addition, Monte Carlo analysis is conducted to characterize the impact of the following factors: (1) uncertainties in the QSPR-estimated chemical-specific parameters; (2) variability in physiological parameters; and (3) variability in exposure patterns. The results indicate that uncertainty in chemical-specific parameters makes only a minor contribution to the overall variability and uncertainty in the predicted TCE concentrations in blood. The model is used in a reverse dosimetry approach to derive estimates of TCE concentrations in drinking water based on given measurements of TCE in blood, for comparison to the U.S. EPA's Maximum Contaminant Level in drinking water. This example demonstrates how a reverse dosimetry approach can be used to facilitate interpretation of human biomonitoring data in a health risk context by deriving external exposures that are consistent with a biomonitoring data set, thereby permitting comparison with health-based exposure guidelines.     

信贷环境与类型差异情景下的PPP项目政府经济承诺决策

为破解政府在PPP项目中存在的"承诺不足"与"承诺过度"决策难题，基于项目类型和信贷环境差异构建四种决策情景，融合优化决策与实物期权理论构建政府经济承诺决策模型，通过Kuhn-Tucker条件分析模型解的条件与边界并设计计算机求解算法，以W市城东污水处理项目为例进行数值模拟探讨政府经济承诺决策规律。结果表明：情景差异将会影响政府经济承诺决策；政府经济承诺可以提升项目价值，但较高的经济承诺未必导致较高的承诺成本；政府应对收益波动型项目给予更低的经济承诺，应在信贷收紧时给予更高的经济承诺，反之亦然；政府可以通过转移收益分配权和增加投资额来降低经济承诺，且不同情景效果具有差异。本文系统刻画了信贷环境与类型差异对经济承诺决策的影响，对于明晰经济承诺的决策成本及其后果、控制PPP项目金融风险、优化我国政府经济承诺决策等具有积极价值。     

辽中北洼锦州A 区东营组浊积扇地震描述研究

针对渤海油田辽中北洼锦州A 区东二下段不同类型浊积扇内部反射结构及其地震响应特征认识难度大的问 题，开展了浊积扇地震描述研究。从浊积扇形成机理出发，根据围区钻遇浊积扇体不同部位探井的相应井段的岩性及 组合结构等典型特征，对不同浊积扇沉积亚相的沉积特征、岩性结构、测井和地震响应特征进行了系统的分析和描述。 在此基础上，建立不同类型浊积扇模型进行地震正演模拟，并对其地震响应特征进行了深入研究，最后利用地震多属 性预测技术对浊积扇的内幕进行了精细地刻画。预测了辽中北洼锦州A 区东营组浊积扇有利储层发育部位，研究结 果对该区浊积扇岩性油气藏勘探具有指导意义。