Multivariate outlier detection in incomplete survey data: the epidemic algorithm and transformed rank correlations

Summary.  As a part of the EUREDIT project new methods to detect multivariate outliers in incomplete survey data have been developed. These methods are the first to work with sampling weights and to be able to cope with missing values. Two of these methods are presented here. The epidemic algorithm simulates the propagation of a disease through a population and uses extreme infection times to find outlying observations. Transformed rank correlations are robust estimates of the centre and the scatter of the data. They use a geometric transformation that is based on the rank correlation matrix. The estimates are used to define a Mahalanobis distance that reveals outliers. The two methods are applied to a small data set and to one of the evaluation data sets of the EUREDIT project.     

傣族龙图腾文化刍议

“龙”是中华民族文化积淀的重要标志,中国人有龙的子孙之说。相关资料证明,“龙”与傣民族图腾之来由亦有密切联系,通过研究可以揭示出各民族宗教艺术融合中产生的多元化变异的现象。     

Bayesian updating of atmospheric dispersion after a nuclear accident

Summary.  We consider a Bayesian forecasting system to predict the dispersal of contamination on a large scale grid in the event of an accidental release of radioactivity. The statistical model is built on a physical model for atmospheric dispersion and transport called MATCH. Our spatiotemporal model is a dynamic linear model where the state parameters are the (essentially, deterministic) predictions of MATCH; the distributions of these are updated sequentially in the light of monitoring data. One of the distinguishing features of the model is that the number of these parameters is very large (typically several hundreds of thousands) and we discuss practical issues arising in its implementation as a realtime model. Our procedures have been checked against a variational approach which is used widely in the atmospheric sciences. The results of the model are applied to test data from a tracer experiment.     

初等数学与高等数学的融合

本文从高等数学对初等数学的渗透，高观点下的初等数学，高等数学对初等数学的直接指导作用三个方面阐述了初等数学与高等数学的融合。     

STTEPping in the right direction? Western classical music in an orchestral programme for disadvantaged African youth

This article looks at STTEP, an outreach project currently housed at the University of Pretoria, which concentrates on the teaching of western orchestral instruments, plus background areas such as music theory, to disadvantaged children and youth from a variety of townships around Pretoria, South Africa. STTEP’s direction can well be described as ‘right’ – pupils are already surrounded by all kinds of global phenomena, and their formal music studies in western classical music are not making them forget their roots. In fact, the contrary has been found to be the case and some interesting cultural fusions are already seen – always a sign of a living culture.     

Human Salmonellosis: Estimation of Dose-Illness from Outbreak Data

The quantification of the relationship between the amount of microbial organisms ingested and a specific outcome such as infection, illness, or mortality is a key aspect of quantitative risk assessment. A main problem in determining such dose-response models is the availability of appropriate data. Human feeding trials have been criticized because only young healthy volunteers are selected to participate and low doses, as often occurring in real life, are typically not considered. Epidemiological outbreak data are considered to be more valuable, but are more subject to data uncertainty. In this article, we model the dose-illness relationship based on data of 20 Salmonella outbreaks, as discussed by the World Health Organization. In particular, we model the dose-illness relationship using generalized linear mixed models and fractional polynomials of dose. The fractional polynomial models are modified to satisfy the properties of different types of dose-illness models as proposed by Teunis et al . Within these models, differences in host susceptibility (susceptible versus normal population) are modeled as fixed effects whereas differences in serovar type and food matrix are modeled as random effects. In addition, two bootstrap procedures are presented. A first procedure accounts for stochastic variability whereas a second procedure accounts for both stochastic variability and data uncertainty. The analyses indicate that the susceptible population has a higher probability of illness at low dose levels when the combination pathogen-food matrix is extremely virulent and at high dose levels when the combination is less virulent. Furthermore, the analyses suggest that immunity exists in the normal population but not in the susceptible population.     

基于虚拟仪器的土壤水分测试系统开发

采用PCl-812PG数据采集卡,基于虚拟仪器技术,以Delphi作为平台开发了土壤含水量测试系统,对AZS -2土壤水分传感器的功能进行了扩展。标定结果及实际应用表明,此系统性能稳定,精度较高。     

我国各民族交往交流交融的空间生产与实践路径

各民族交往交流交融是铸牢中华民族共同体意识的路径选择。民族社会结构的存在和发展为各民族交往交流交融提供了可实现的行动空间及空间生产基础,运用空间生产理论对民族交往交流交融的空间生产与空间结构进行分析,即各民族交往的物质空间生产是基于共同利益与互惠发展的经济交往、各民族交流的符号空间生产是注重共有价值和情感寄托的文化交流、各民族交融的精神空间生产是强调生活互嵌和共生体验的精神交融。基于此,加强各民族交往交流交融的实践路径应是推动民族地区经济交往,构建以平衡互惠为原则的多民族经济圈;促进民族乡土文化交流,发展以情感共鸣为重心的乡村文化中心;深化各族群众生活交融,规划以结构互嵌为内核的社区公共空间。通过上述路径,达成铸牢中华民族共同体意识的根本目标。     

利用数控增益放大器提高A/D转换器的分辨率

文章介绍利用数控增益放大器LH0086大幅度提高A／D转换器分辨率的方法,可将8位A／D转换器的分辨率提高到接近16位A／D的水平,适用于高速数据系采集系统,给出了相应的硬件原理图和软件框图。     

受控核聚变的一种新途径──低能注入式磁盖势阱约束法受控核聚变

提出了磁盖势阱（ＭＬＰＷ）一种静电装置,该装置是在球形静电势阱的外围加上磁盖而构成的,可用于受控核聚变．通过建立磁盖势阱中带电粒子的运动方程并取单粒子谐振子近似以及运用自洽场的统计方法,球形聚变炉内大量带电粒子的集体行为被计算机所研究和模拟．由于使用了电场与磁场的联合约束,与单独的磁约束或惯性约束受控核聚变相比,所需达到的技术指标将有所改善,工程技术上的难度也会有所降低