LBS在监外服刑中的应用

移动位置服务在未来几年内将成为移动运营商的主要增值手段,中国联通今年将在CDMA1x网络中启动gpsOne定位业务。通过分析比较各种定位技术,根据监外服刑监管系统的要求,提出采用中国联通的CDMA1x网络和gpsOne定位平台来进行数据传输和位置跟踪的监管系统整体解决方案,并在系统架构、电子镣铐的软硬件设计等方面进行了初步的探讨。     

作为随机振动的海冰变化模型

本文从B.Saltzman的海温—海冰模式出发,得到了一个描述海冰范围变化的随机气候模型,接着对模型的性质进行了一些分析和讨论,并把从模型得到的模拟谱与计算的南极海冰扩展范围的观测谱做了比较。     

Period Change of CU Pegasi

On the basis of the published times of minima and our own observations, we analysed the period change of the Algol-type eclipsing binary CU Pegasi. Over almost seventy years of observations, the parabolic period change has been clearly seen as dP/dt = 1.38 × 10⁻⁶ d/year. The estimated mass transfer in the system is about 1 × 10⁻⁷ M_M⊙/year.     

Modelling risk and risking models: The diffusive boundary between science and policy in volcanic risk management

This article examines the science–policy interface in volcanic risk assessment. It analyses empirical data from research on Montserrat, where new volcanic risk assessment methodologies were pioneered. We discuss the ways in which these methods contributed towards the ordering of scientific advice in its geographical context, and we provide examples of the complex and overlapping topologies that are assembled in a volcanic eruption. In this case, the science–policy interface can be conceptualised as diffusive: both science and policy contain multiple overlapping networks of actors, objects and ideas that interact with one another through flows of responsibilities, attribution, identity and interpretation. Volcanic risk management involves negotiation of conceptual, relational and physical boundaries, and as a result requires the use of qualitative and quantitative methods across human and physical geography.     

A history of the global understanding of the Earth

The author contributes to the development of a history of the global understanding of the Earth. He summarizes the main steps in the knowledge of the Earth's interior from antiquity to the present time and draws some lessons from this history.     

On the Substantial Spatial Spread of the Quadrantid Meteoroid Stream

We explored the substantial spatial spread of the Quadrantid stream, based on the backward integration of orbital motions of the Quadrantids, impulsively perturbed by Jupiter. We found that the Jovian impulses can widely spread out them in the early twentieth century, especially their perihelia extended by a factor of ∼90 than those at the observed epoch. We regarded the spread as the intrinsic one of the Quadrantid stream itself.     

Tectonic geomorphology of the San Andreas Fault zone from high resolution topography: An example from the Cholame segment

High resolution topographic data along fault zones are important aids in the delineation of recently active breaks. A 15 km-long portion of the south-central San Andreas Fault (SAF) along the southern Cholame segment contains well preserved tectonic landforms such as benches, troughs, scarps, and aligned ridges that indicate recurring earthquake slip. Recently acquired LiDAR topographic data along the entire southern SAF (“B4” project) have shot densities of 3–4 m^− 2. Computed from the LiDAR returns, Digital Elevation Models (DEMs) of 0.25 to 0.5 m resolution using local binning with inverse distance weighting and 0.8 m or larger search radii depict the tectonic landforms at paleoseismic sites well enough to assess them confidently. Mapping of recently active breaks using a LiDAR-only based approach compares well with aerial photographic and field based methods. The fault zone varies in width from meters to nearly 1 km and is comprised of numerous en echelon meter to kilometer-length overlapping sub parallel fault surfaces bounding differentially moving blocks that elongate parallel to the SAF. The semantic variations of what constitutes “active” and the importance of secondary traces influence the breadth and complexity of the resulting fault trace maps.     

TerEx Toolbox for semi‐automated selection of fluvial terrace and floodplain features from lidar

Terraces and floodplains are important indicators of near‐channel sediment dynamics, serving as potential sediment sources and sinks. Increasing availability of high resolution topography data over large areas calls for development of semi‐automated techniques for identification and measurement of these features. In this study we introduce a novel tool that accommodates user‐defined parameters including, a local‐relief threshold selected by a variable‐size moving window, minimum area threshold, and maximum distance from the channel to identify and map discrete terrace and floodplain surfaces. Each of the parameters can easily be calibrated for a given watershed or reach. Subsequently, the tool automatically measures planform area, absolute elevation, and height relative to the local river channel for each terrace polygon. We validate the tool in two locations where terrace maps were previously developed via manual digitization from lidar and extensive field mapping campaigns. The tool is also tested on six different types of rivers to provide examples of starting selection parameters, and to test effectiveness of the tool across a wide range of landscapes. Generally, the tool provides a high quality draft map of terrace and floodplain surfaces across the wide range of environmental conditions for which it has been tested. We find that the tool functions best in catchments where the terraces are spatially extensive, with distinct differences between the terrace and floodplain. The most challenging environments for semi‐automated terrace and floodplain mapping include steep catchments with dense riparian vegetation, and very small terraces (~10 m² in areal extent). We then apply the tool to map terraces and floodplains in the Root River watershed, southeastern Minnesota and generate exceedance plots for terrace heights. These plots provide a first pass analysis to indicate the tributaries and reaches of the river where terraces constitute a significant source of sediment. Copyright © 2013 John Wiley & Sons, Ltd.