浅析山西长治数字测震台网维护工作

文章概述了山西长治数字测震台网的系统构成,并对台网的维护工作从维修次数、故障类型等方面进行分析,认为,要保证观测质量必须做好五方面的维护工作。     

几种新的河网分维及其制图特征

利用分形几何原理，推导出几种新的河网分维，并讨论了它们的制图特征。     

监测网的稳定性分析

讨论了变形监测网的参考系问题，举例说明了不同的参考基准对应着完全不同的位移场。对监测网点位稳定性进行了分析，重点介绍了平均间隙法，稳健迭代权法和单点位移分量法。     

Modelling road surface sediment production using a vector geographic information system

Field investigations indicate that unpaved roads are the largest sediment source on St John, US Virgin Islands. Cross-sectional measurements of eroded road surfaces were used to establish an empirical relationship to predict annual road surface erosion as a function of road gradient and contributing drainage area. A model (ROADMOD) for estimating and mapping average annual sediment production from a road network was developed by combining this empirical relationship with a series of network algorithms to analyse road data stored in a vector geographic information system. ROADMOD was used to estimate road surface erosion in two St John catchments with very different road densities but similar land cover, topography and soils. Unpaved roads were found to increase sediment production in the more densely roaded catchment by a factor of three to eight, and in the less-roaded catchment by a factor of 1·3–2·0. Turbidity measurements in the receiving bays of these two catchments are consistent with model predictions and observed sediment delivery processes. Although this model was developed specifically for St John, it can easily be adapted to other locations by substituting a locally derived predictive equation for road erosion. Model assumptions, limitations and potential improvements are discussed. © 1998 John Wiley & Sons, Ltd.     

基于HBCORS的网络RTK技术在海籍测量中的应用

简单介绍网络RTK技术工作原理,以秦皇岛市昌黎县海籍调查为例,详细说明基于河北连续运行参考站(HBCORS)的网络RTK技术在海籍测量中的应用,并作出精度统计分析,最后对网络RTK技术误差来源及解决方法进行分析,给出了有益的结论。     

IC-D新型脉冲标定电路的设计与应用——华北地区遥测地震台网联网论文续七

介绍了一种适用于遥测地震台网台站钟控脉冲标定的IC-D新型脉冲标定电路.     

A cost path and network analysis methodology to calculate distances along a complex river network in the Peruvian Amazon

Distance is a key variable in explicating environmental, social, and economic conditions and in defining spatial and temporal patterns. Prior research has primarily focused on using simple to complex algorithms for calculating distances along road networks. In contrast, few algorithms are available for distance calculations along fluvial networks which are often more erratic, divergent and transient than road networks. Fluvial transportation is relied upon worldwide, particularly in developing regions, where communities use river networks for transportation, access to natural resources and for trade and commerce. This paper presents a methodology developed for mapping complex fluvial networks for travel distance analysis. The methodology was applied in four major river basins in western Amazonia over some 35,000 km of river length and incorporating 919 communities as origins/destinations. A cost path and network analysis methodology was created using vector and raster datasets in a Geographic Information System (GIS) to assess interactions among communities and the distances traveled by river to reach district capitals, major urban centres and marketplaces. An accuracy assessment using distance values calculated from a previous study using a different methodological approach in the region as well as Google Earth Pro, found a high degree of concordance for distance calculations. Our methodology creates a very flexible approach for complex river systems that can be use to calculate river distances in an adaptive and efficient manner and that can be use in other regions of the world where rural communities must rely on rivers for transportation.     

Challenging the boundaries of entrepreneurship: The spatialities and practices of UK ‘Mumpreneurs’

This paper examines the spatialities and practices of an illustrative sample of UK mumpreneurs, a sub-group of female entrepreneurs who operate at the interface between paid work and motherhood, who are increasing numerically, and who are carving for themselves, a sub-culture of entrepreneurship. They have great policy-importance, not least because the UK government has recognised mothers as a group who need to be encouraged into business ownership. Employing mixed methods with emphasis on qualitative approaches, the research findings suggest that policy makers need to understand better some key aspects of this entrepreneurial activity before their interventions can be effective.     

深基坑工程变形预报神经网络法的初步研究

提出了深基坑变形预报的人工神经网络法,详细介绍了该方法的建模和应用实例。预报结果与实测值较为吻合,从而表现在深基坑工程中利用该方法进行变形预报是可行的。