关于有限混合总体的抽样

本文讨论混合总体的抽样性质,该总体由有限几个子体按比例充分混合得到.采样的均值与方差得到研究。我们也讨论了在保证采样质量的前提下对每一子体的最优配额问题.     

全国环境天然放射性水平调查中的数据处理规定

本文总结了全国环境天然放射性水平调查中数据处理的质量保证工作。包括按行政区域的统计程序和有关规定，各类加权均值及其（等效）单次测量标准差的计算，居民剂量的计算公式和参数，陆地γ辐射剂量率和天然贯穿辐射剂量率的计算，数据处理和计算结果的复核要求。     

Letter to the Editor.

In this letter, D. E. Berlyne, President of the Canadian Psychological Association, explains the organization's decision to co-sponsor the 1972 Survey of Psychologists in the United States and Canada. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The design of optimal sampling schemes for local estimation and mapping of regionalized variables—II: Program and examples

A FORTRAN IV program, OSSFIM, is presented for calculating estimation variances when interpolating by kriging from regular rectangular and triangular grids of data and previously-determined semi-variogram. The variances are computed for a range of grid spacings and block sizes, and the results graphed. The user chooses a block size, and can read from the appropriate graph the sample spacing corresponding to any prescribed maximum tolerable error. This is the optimal sampling scheme. Use of the program is illustrated with two examples showing different types of variation in soil. In one, the pH of topsoil is isotropic with a spherical semi-variogram and negligible nugget variance. An equilateral triangular grid is the best sampling scheme; it is approximately 10 per cent more efficient than a square grid. In the other example, variation is linear but anisotropic with a large nugget variance. In these circumstances, a triangular grid has no advantage over a rectangular one, which should be elongated in the ratio 1.88 to I in the direction of minimum variation.     

电力勘测设计行业CAD电子文件的管理和利用

根据国家标准《CAD电子文件光盘存储、归档与档案管理要求》,针对电力勘测设计单位CAD电子文件的实际管理和利用情况,对CAD电子文件的收集、整理、鉴定、归档、管理和利用的全过程管理进行了阐述。     

Differences in safety belt use by race

The purpose of the study was to identify daytime differences in safety belt use by race. Safety belt use was investigated in a direct observation survey of drivers and front-outboard passengers throughout Michigan. Data were weighted to calculate statewide safety belt use rates by race. Race was assessed visually by trained observers. The study showed that motor vehicle occupants identified as Black had significantly lower safety belt use than those occupants identified as White or Other.     

An accident waiting to happen: a spatial approach to proactive pedestrian planning

There are about 75,000 pedestrian crashes in the United States each year. Approximately 5000 of these crashes are fatal, accounting for 12% of all roadway deaths. On college campuses, pedestrian exposure and crash-risk can be quite high. Therefore, we analyzed pedestrian crashes on the campus of the University of North Carolina at Chapel Hill (UNC) as a test case for our spatially-oriented prototype tool that combines perceived-risk (survey) data with police-reported crash data to obtain a more complete picture of pedestrian crash-risk. We use spatial analysis techniques combined with regression models to understand factors associated with risk. The spatial analysis is based on comparing two distributions, i.e. the locations of perceived-risk with police-reported crash locations. The differences between the two distributions are statistically significant, implying that certain locations on campus are perceived as dangerous, though pedestrian crashes have not yet occurred there, and there are actual locations of police-reported crashes that are not perceived to be dangerous by pedestrians or drivers. Furthermore, we estimate negative binomial regression models to combine pedestrian and automobile exposure with roadway characteristics and spatial/land use information. The models show that high exposure, incomplete sidewalks and high crosswalk density are associated with greater observed and perceived pedestrian crash-risk. Additionally, we found that people perceive a lower risk near university libraries, stadiums, and academic buildings, despite the occurrence of crashes.     

Driver hand-held mobile phone use and safety belt use

The purposes of the study were to identify hand-held mobile phone use trends for Michigan and to compare safety belt use between users and nonusers. Mobile phone and safety belt use was investigated by a direct observation survey of drivers at intersections in Michigan. Data were weighted to calculate mobile phone use and safety belt use rates statewide. The study showed 2.7% of Michigan drivers were using a mobile phone at any given daylight time. Safety belt use of current mobile phone users was significantly lower than those not using mobile phones.     

数字区调新技术新方法—RS_OrthoMapper系统研制开发

为了适应当今数字区调工作的需要,开发一套3S技术有机结合简单实用的数字区调野外工作平台或软件系统,已成为燃眉之急。论文介绍了数字区调新技术新方法--RS_OrthoMapper系统研制与开发的基本需求、系统的总体结构与设计、系统实现等,并给出了系统中一些重要的逻辑视图。该系统在西藏昌务场和青海阿拉克湖等地区数字区调填图中示范应用,获得良好效果。     

A process of knowledge discovery from web log data: Systematization and critical review

This paper presents a comprehensive survey of web log/usage mining based on over 100 research papers. This is the first survey dedicated exclusively to web log/usage mining. The paper identifies several web log mining sub-topics including specific ones such as data cleaning, user and session identification. Each sub-topic is explained, weaknesses and strong points are discussed and possible solutions are presented. The paper describes examples of web log mining and lists some major web log mining software packages.