Designing and integrating composite networks for monitoring multivariate gaussian pollution fields

Networks of ambient monitoring stations are used to monitor environmental pollution fields such as those for acid rain and air pollution. Such stations provide regular measurements of pollutant concentrations. The networks are established for a variety of purposes at various times so often several stations measuring different subsets of pollutant concentrations can be found in compact geographical regions. The problem of statistically combining these disparate information sources into a single 'network' then arises. Capitalizing on the efficiencies so achieved can then lead to the secondary problem of extending this network. The subject of this paper is a set of 31 air pollution monitoring stations in southern Ontario. Each of these regularly measures a particular subset of ionic sulphate, sulphite, nitrite and ozone. However, this subset varies from station to station. For example only two stations measure all four. Some measure just one. We describe a Bayesian framework for integrating the measurements of these stations to yield a spatial predictive distribution for unmonitored sites and unmeasured concentrations at existing stations. Furthermore we show how this network can be extended by using an entropy maximization criterion. The methods assume that the multivariate response field being measured has a joint Gaussian distribution conditional on its mean and covariance function. A conjugate prior is used for these parameters, some of its hyperparameters being fitted empirically.     

网上CAI

用好现代先进技术,开展网络建设,是教育信息化的第一步。本文基于这一思想,介绍了网上CAI的设计思路,描述了该系统的功能,以及实现系统所采用的技术措施。     

用信号流图分析开关电容网络

大型开关电容（SC）网络往往是由许多SC网络级联而成的,而级联之前要对SC子网络进行优化设计,就必须得到子网络的网络函数表达式。本文介绍了一种通过观察SC网络的拓扑结构,直接得到网络的信号流图（SFG）,从而得到所需要的网络数的方法。     

远程辅助教学系统的研究

本文讨论了网上远程系统的智能系统模型和实现方法。实现教师和学生的远程交互,对学生学籍进行管理,并有测试功能便于学生自测,可记录学生的平时成绩供教师参考。     

中国城市化与生态环境协调发展预警系统研究

本文构建了城市化与生态环境协调发展预警指标体系,并对1991～2010年中国城市化与生态环境的协调度进行了测算及预测,根据协调度建立了预警系统,并对90年代以来中国城市化与生态环境的协调发展进行了分析。结果表明,2007年以来,中国的生态环境不断恶化,城市化与生态环境的协调度不断下降,保护生态环境成为城市化进程中的重要问题。     

Discrete Multicolour Random Mosaics with an Application to Network Extraction

We introduce a class of random fields that can be understood as discrete versions of multicolour polygonal fields built on regular linear tessellations. We focus first on a subclass of consistent polygonal fields, for which we show Markovianity and solvability by means of a dynamic representation. This representation is used to design new sampling techniques for Gibbsian modifications of such fields, a class which covers lattice‐based random fields. A flux‐based modification is applied to the extraction of the field tracks network from a Synthetic Aperture Radar image of a rural area.     

A network algorithm for the exact treatment of the 2×k contingency table

A common statistical problem encountered in biomedical research is to test the hypothesis that the parameters of k binomial populations are all equal. An exact test of significance of this hypothesis is possible in principle, the appropriate null distribution being a normalized product of k binomial coefficients. However, the problem of computing the tail area of this distribution can be formidable since it requires the enumeration of all sets of k binomial coefficients whose product is less than a given constant. Existing algorithms, all of which rely on explicit enumeration to generate feasible binomial coefficients     

Extreme probabilities for contingency tables under row and column independence with application to fisher's exact test

Theorerms are proved for the maxima and minima of IIR_i!/IIC_j!/T!II_yij ! over r× c contingcncy tables Y=(y_ij) with row sums R₁,…,R_r, column sums C₁,…,C_c, and grand total T. These results are imlplemented into the network algorithm of Mehta and Patel (1983) for computing the P-value of Fisher's exact test for unordered r×c contingency tables. The decrease in the amount of computing time can be substantial when the column sums are very different.     

网络环境下图书馆采访工作初探

分析了网络环境给图书馆工作所带来的机遇和优势 ,认为它不仅使图书馆的采购方式得到了优化 ,而且也大大提高了购书质量和采购效率 ,节约了大量资金。据此 ,提出面对新的形势发展 ,应该通过强调提高采访人员素质、实现资源共享、建立文献出版信息数据库及相关信息库、合理选择各类信息资源等措施来进一步加强图书馆的采访工作 ,以便真正提升建立高质量馆藏所产生的实际应用价值。     

时代发展对科技期刊青年编辑素质的要求

科技期刊是科技知识和信息传播的重要载体,对促进科技进步和推动学术交流具有十分重要的意义。内容是科技期刊的"灵魂",执掌"灵魂"的是编辑。青年编辑既有学历层次高、专业学习系统、英语和计算机应用水平高等优势,同时,也存在经验不足、编辑业务技能欠缺、心理浮躁等普遍问题。数字化、网络化技术的发展,编辑的职业化程度更高,编排校一体化的工作模式为青年编辑的更快成长提供了有利条件。