基于蒙特卡洛方法的油气井管柱可靠性评估*

为提高油气井管柱服役的安全性,采用数据统计与可靠性理论评估油气井管柱可靠性。首先,识别影响管柱外载及其参数的变量,构建油气井管柱安全极限状态方程;然后,采集模型变量数据,确定变量分布与参数,形成油气井管柱可靠性数值模型;最后,通过蒙特卡洛方法计算影响管柱可靠性的关键变量和不同置信度水平下管柱剩余强度分布及安全系数取值。结果表明:目标区域油气井管柱剩余强度符合正态分布,得到不同置信度水平下管柱的可靠度,管柱的安全系数取值范围可满足管柱安全设计要求,所构建的方法可为实际生产中油气井井筒管柱安全评价提供技术支撑。     

关于中国在用汽车排污控制的若干问题--柴油车部分

文章结合《点燃式发动机汽车排气污染物排放限值及测量方法（双怠速法及简易工况法）》（GB18285—2005）修订中的重大问题阐述中国在用汽油车排气烟度控制方面的新要求。主要包括：增加高怠速排污检测、对电喷汽车增加过量空气系数（λ）的限定、新规定了国1以来的在用汽油车双怠速排放限值、双燃料车要对两种燃料分别检测、对简易工况检测法作了规定、制定简易工况检测法排放限值的基本原则和方法、供地方参考的排放限值等。     

河网水质数学模型的参数估算

本文以无锡县河网水质数学模型的参数估算为例，根据河流的性质、水流特征、污染源的类型，选择５条河流进行现场观测，综合考虑不同河流的分析结果，研究了适用于平原河网水质数学模型的参数估算的方法。     

通波塘水量水质一维动态模拟及水环境容量

本文在研究通波塘水文特征和水质特征的基础上,推导出通用性较好的一维动态水量水质数学模型。该模型基本反映了通波塘水量水质的时变情况。文章对通波塘水环境容量作了计算,并提出了改善水质的建议。     

Including model uncertainty in estimating variances in multiple capture studies

We present bootstrap-based methods which incorporate model uncertainty in estimating variances in multiple capture studies. Each of our three methods has a specific set of properties, and we discuss when each method should be used. Our first method can be used in any multiple capture setting, but it gives an estimate of the variance conditional on the number of observed animals. Our other two methods yield estimates of the unconditional variance; they require good estimates of part or all of the specific probability model, respectively. Smoothed estimated cell probabilities are utilized by the latter method. We contrast the three methods on a real-life data set, and then conduct simulations for a simple setting. Finally, we detail the use of our methodology for specific settings and discuss adaptations for tag-return studies.     

简易柱式无土栽培法

在立柱栽培技术发展过程中 ,简易柱式法最先是在 1994～ 1995年初发展起来的 ,并在当年推广到江苏张家港市和河北遵化市 ,后来在此基础上发展了现被广泛推广应用的标准型柱式无土栽培法[1～ 3] ,但该方法中的盆钵是由高强度抗老化的ＡＢＳ工程塑料铸塑而成 ,价格贵 ,安装 1亩 ( 6 6 6 .7ｍ2 )约需6万元人民币 ,在中小城市及农村推广使用不易 ,因此简易柱式无土栽培技术的优点值得重视 ,讨论如下 :1　简易立柱的组装简易柱是由包裹材料柱壁、柱体和栽培基质构成 .柱壁是新制丙烯 (ｐｏｌｙｐｒｏｐｙｒｅｎｅ)编织材料 (俗称“蛇皮”带 ) ,裁…     

市场调研中原始信息的收集和分析

在市场调研过程中对原始信息的统计和运用往往关系到整个市场调研的准确性和真实性,各类营销管理职能的选择依据都来源于准确、科学的前期调研,因此,对市场调研工作中市场一手数据和原始信息的统计和运用进行分析与整理、概述原始信息收集工作的要求和方法,是任何一个营销工作者所必须重视和学习的一项基本功.参4.     

The Truth About Science: A middle school curriculum teaching the scientific method and data analysis in an ecology context

The Truth About Science is a 40-lesson middle school curriculum module that teaches the process of scientific research, integrating mathematics and science concepts and skills. The goal of the curriculum is to teach students to think systematically and statistically about science inquiry. Students participate in each step of the scientific inquiry process, from asking testable research questions, designing unbiased experiments, and collecting their own data, to analyzing these data via graphical representations and statistical summaries, and communicating their research results as both poster and oral presentations. While the necessary statistical skills depend on difficult and abstract mathematical concepts, middle school students have been successful in applying them to their own research projects. The curriculum meets local and national standards in science and mathematics education and fills a gap in available educational materials. It has been piloted and revised through multiple iterations and published by the National Science Teachers Association Press. Feedback from teachers and students has been extremely positive.     

Accounting for geophysical information in geostatistical characterization of unexploded ordnance (UXO) sites

Efficient and reliable unexploded ordnance (UXO) site characterization is needed for decisions regarding future land use. There are several types of data available at UXO sites and geophysical signal maps are one of the most valuable sources of information. Incorporation of such information into site characterization requires a flexible and reliable methodology. Geostatistics allows one to account for exhaustive secondary information (i.e.,, known at every location within the field) in many different ways. Kriging and logistic regression were combined to map the probability of occurrence of at least one geophysical anomaly of interest, such as UXO, from a limited number of indicator data. Logistic regression is used to derive the trend from a geophysical signal map, and kriged residuals are added to the trend to estimate the probabilities of the presence of UXO at unsampled locations (simple kriging with varying local means or SKlm). Each location is identified for further remedial action if the estimated probability is greater than a given threshold. The technique is illustrated using a hypothetical UXO site generated by a UXO simulator, and a corresponding geophysical signal map. Indicator data are collected along two transects located within the site. Classification performances are then assessed by computing proportions of correct classification, false positive, false negative, and Kappa statistics. Two common approaches, one of which does not take any secondary information into account (ordinary indicator kriging) and a variant of common cokriging (collocated cokriging), were used for comparison purposes. Results indicate that accounting for exhaustive secondary information improves the overall characterization of UXO sites if an appropriate methodology, SKlm in this case, is used.