Using Bayesian belief networks to analyse the stochastic dependence between interevent time and size of earthquakes

The purpose of this article is to show how Bayesian belief networks can beused in analysis of the sequence of the earthquakes which have occurred in a region, to study the interaction among the variables characterizing eachevent. These relationships can be represented by means of graphs consistingof vertices and edges; the vertices correspond to random variables, whilethe edges express properties of conditional independence. We have examinedItalian seismicity as reported in two data bases, the NT4.1.1 catalogue and the ZS.4 zonation, and taken into account three variables: the size of thequake, the time elapsed since the previous event, and the time before the subsequent one. Assigning different independence relationships among these variables, first two couples of bivariate models, and then eight trivariatemodels have been defined. After presenting the main elements constituting a Bayesian belief network, we introduce the principal methodological aspects concerning estimation and model comparison. Following a fully Bayesian approach, prior distributions are assigned on both parameters and structuresby combining domain knowledge and available information on homogeneous seismogenic zones. Two case studies are used to illustrate in detail the procedure followed to evaluate the fitting of each model to the data sets andcompare the performance of alternative models. All eighty Italian seismogenic zones have been analysed in the same way; the results obtained are reportedbriefly. We also show how to account for model uncertainty in predicting a quantity of interest, such as the time of the next event.     

基于插件技术的大地测量数据集成

研究了当前大地测量数据采集模式,分析了插件系统的信息流程,建立了大地测量数据采集插件接口和数据接口,实现了各种格式的大地测量外业数据的集成,增强了系统的扩展性.     

多波列高密度地震影像法在沪崇隧道工程地质调查中的应用

地震方法在现代地质工程调查中有着广泛的应用，而在沪崇隧道中多波列地震影像法的应用，效果明显，前景看好。     

甘肃省测绘地理信息成果分发服务系统的设计与实现

根据现代社会各行业对测绘地理信息档案成果的需求,档案信息化已成为档案存储、管理、应用的趋势和要求。本文基于档案信息化项目背景,阐述和分析了测绘地理信息成果分发服务系统的实现与集成等关键技术。     

The effect of biological and physical disturbances on the transport of arsenic from contaminated estuarine sediments

From the distribution of dissolved and solid arsenic species in a contaminated estuarine sediment and measured rates of flux of the various arsenic species we propose an empirical model for the cycling of arsenic between sediments and water column. The chemical form of arsenic in the sediment was largely determined by the redox state of the sediment. Arsenite was the dominant dissolved and solid species in the deeper reduced sediment, and arsenate was dominant in the oxidized surface layer. Arsenite in the interstitial water diffused toward the surface layer, where it was mostly oxidized to arsenate prior to leaving the sediments. Some arsenate adsorbed to the surface sediments and produced a surface layer enriched in arsenic. Small concentrations of methyl and dimethyl arsenic were produced in the sediments, and these also diffused into the overlying water.Nereis succinea, a burrowing polychaete, affected distribution and flux of arsenic from the sediments by its production of irrigated burrows. These burrows increased both the effective surface area of the sediment and the diffusion of arsenic by a factor of five. When the relative effects of the activities of Nereis succinea and physical resuspension are compared, results indicate that although physical resuspension can produce large pulses of materials from contaminated sediments, continuous biological activity is likely to be more important in the mobilization of contaminants from sediments in many estuarine environments.     

Shaft capacity of pre-bored grouted planted nodular pile under various overburden pressures in dense sand

Abstract

This paper presents the results of a series of model tests performed to study the shaft capacity of pre-bored grouted planted nodular (PGPN) pile in dense sand. The influence of the vertical overburden pressure on the shaft capacity of the PGPN pile is also investigated based on the test results. The test piles were equipped with strain gauges to measure the axial loads during the loading process, moreover, a foam plate was buried beneath pile tip to eliminate the influence of tip resistance on the shaft capacity. Some conclusions can be drawn based on the test results: the peak skin friction of PGPN pile increases with the increase of vertical overburden pressure applied on the foundation soil, while the rate of increase decreases with the increasing overburden pressure; the surface of the pile–soil interface of PGPN pile is relatively rough, and significant dilatant increase in lateral stress occurs during the loading process.     

The Model-Free Analysis of Growth Curves

Abstract.

• 1) An incremental (graphical in this presentation) method for the analysis of growth curves has revealed actual, as opposed to modelled, growth rates. Here, we present data derived from the scallop Pecten maximus (L.). These actual rates exhibit differences in annual environmental conditions and differences between local populations.
• 2) Both first and second derivatives (growth rate and acceleration ? deceleration in growth rate, respectively) can be obtained from plotted size ? age data: here, size is represented by the height of the flat left valve.
• 3) The analysis of age class data from different years allows one to estimate maximum theoretical rates in any given year.
• 4) The analysis of individual data naturally reveals more than the analysis of average data, reinforcing the average nature of population growth parameters.
• 5) The departure of average data from the maxima revealed by the analysis of growth rate and acceleration allows one to identify changes in environmental conditions in different years.
• 6) The Von Bertalanffy growth curve has been used as an example because it is well known and widely used; however, any desired growth curve can be fitted by the method discussed here.

     

陇西盆地晚更新世风成堆积物粒度参数的对比

计算了末次冰期旋回陇西盆地的黄土古土壤和风成砂的粒度参数，并对图解法与矩值法粒度参数进行了对比。结果表明，对黄土古土壤来说两种方法所获得的平均粒径基本相同，分选系数、偏度和偏态的相关性逐渐降低，对风成砂和砂黄土来说，除了平均粒径呈较好的线性相关外，其他参数则差别很大。造成这种差异的主要原因是由于它们粒度组分的分布不同所致。图解法主要反映了样品总体中主要粒度组分的粒度特征，而矩值法则反映了样品的总体特征。在沉积环境的分析和比较中，应充分考虑这两种方法的差异，并建立不同的标准。激光粒度仪和吸管法对平行样品测试的图解计算结果表明，粒度参数的变化趋势比较接近。     

浏览器结构的Unix用户界面设计框架

Unidim是一个基于浏览器结构的Unix用户界面原型,它集直接操作与命令语言两种交互方式于一体,既为用户建立了一个WIMPS交互环境,又保留了命令语言特有的灵活性和强大能力。简要介绍了Unidim总的设计思想及其主要部份的设计方案。     

水面上大气稳定度的作用

讨论了水-气交界面上大气稳定度对C_D与U_(10)和U.与U_(10)等关系的影响,还探讨C_D如何受制于大气稳定度参量(TV)。指出大气稳定度的效应是明显的。由于所得的方程是以湖泊、内陆海、海湾和海洋的实测资料为基础的,且数据达605组之多,故文中方程较具普遍性。所提方程都经初步验证。