Near real-time geoprocessing on the grid: A scalable approach to road traffic monitoring     

Aengus McCullough  Philip James  Stuart Barr 《International journal of geographical information science》2013,27(10):1939-1957

The geospatial sensor web is set to revolutionise real-time geospatial applications by making up-to-date spatially and temporally referenced data relating to real-world phenomena ubiquitously available. The uptake of sensor web technologies is largely being driven by the recent introduction of the OpenGIS Sensor Web Enablement framework, a standardisation initiative that defines a set of web service interfaces and encodings to task and query geospatial sensors in near real time. However, live geospatial sensors are capable of producing vast quantities of data over a short time period, which presents a large, fluctuating and ongoing processing requirement that is difficult to adequately provide with the necessary computational resources. Grid computing appears to offer a promising solution to this problem but its usage thus far has primarily been restricted to processing static as opposed to real-time data sets. A new approach is presented in this work whereby geospatial data streams are processed on grid computing resources. This is achieved by submitting ongoing processing jobs to the grid that continually poll sensor data repositories using relevant OpenGIS standards. To evaluate this approach a road-traffic monitoring application was developed to process streams of GPS observations from a fleet of vehicles. Specifically, a Bayesian map-matching algorithm is performed that matches each GPS observation to a link on the road network. The results show that over 90% of observations were matched correctly and that the adopted approach is capable of achieving timely results for a linear time geoprocessing operation performed every 60 seconds. However, testing in a production grid environment highlighted some scalability and efficiency problems. Open Geospatial Consortium (OGC) data services were found to present an IO bottleneck and the adopted job submission method was found to be inefficient. Consequently, a number of recommendations are made regarding the grid job-scheduling mechanism, shortcomings in the OGC Web Processing Service specification and IO bottlenecks in OGC data services.  相似文献   

Climatic Change and Desert Vegetation Distribution: Assessing Thirty Years of Change in Southern Nevada's Mojave Desert     

Ross J. Guida  Scott R. Abella  William J. Smith Jr.  Haroon Stephen  Chris L. Roberts 《The Professional geographer》2013,65(2):311-322

A major theme in physical geography and biogeography is understanding how vegetation changes across geographic gradients during climate change. We assess shifts in distributions of fifteen Mojave Desert plant species based on a 2008 resurvey of 103 vegetation transects that were established in 1979. We model changes in species distributions using Maximum Entropy (Maxent) with environmental and climate variables to predict probability of species’ occurrences. Climate during the ten-year period preceding the 2008 vegetation survey was 1.5°C warmer and 3 cm per year of precipitation drier than the ten years preceding 1979. Species inhabiting the highest elevations and strongly correlated with precipitation displayed areal reductions from 1979 through 2008.  相似文献   

Analytical solutions for co- and counter-current imbibition of sorbing, dispersive solutes in immiscible two-phase flow     

Karen Sophie Schmid  Sebastian Geiger  Kenneth Stuart Sorbie 《Computational Geosciences》2012,16(2):351-366

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牙形石SHRIMP微区原位氧同位素分析方法   总被引：7，自引：0，他引：7  

周丽芹  Ian Stuart WILLIAMS  刘建辉  纪战胜  肖渊甫  刘敦一 《地质学报》2012,86(4):611-618

氧同位素温度计已被用于古温度变化研究多年。生物化石磷酸盐中的氧同位素组成对古气候环境变化响应灵敏,牙形石在古生代到中生代的古海洋地层中广泛存在,并具有较为重要的地层学意义,是研究古温度变化的最佳样品之一。SHRIMP具备高分辨、高灵敏、高精度和微量及原位微区分析的特点,可以进行20μm范围内的原位(in-situ)同位素分析。本文介绍了作者利用SHRIMP IIe-MC建立的牙形石微区原位氧同位素分析方法,这是国内关于该方法的首次报导。本文对磷灰石标准样Durango进行了测定,连续七昼夜获得的253次测定结果,平均值为δ18 Oapatite=9.78‰±0.29‰,与该标准参考值δ18 Oapatite=9.81‰±0.25‰(Williams,未刊资料)一致。作者并以二叠系—三叠系界线上下海水温度变化研究为示范,对采自西藏文布当桑二叠系—三叠系剖面上的49个层位中的237件牙形石样品进行了914个氧同位素分析,为研究二叠系—三叠系界线上发生的生物灭绝事件前后的海水温度变化提供了可靠详实的数据。  相似文献   

The Cainozoic geology of the Middle Shoalhaven Plain     

Bryan P. Ruxton  Graham Taylor 《Australian Journal of Earth Sciences》2013,60(1-2):239-246

The Middle Shoalhaven Plain is a large, tray‐like depression bounded in the west by the Mulwaree fault and in the east by cliffed Permian sediments. The plain is probably Mesozoic in origin and was partially alluviated during the Early to mid‐Eocene. Much of the plain and sediments were covered by basalts during the Late Eocene. This was followed by an episode of deep weathering, which culminated in the formation of widespread bauxitic and lateritic crusts and manganocrete and silcrete during the mid‐Tertiary. A second minor weathering event is recorded during the latest Tertiary to Early Pleistocene. Two new basalt dates are consistent with earlier ones at about 43 Ma. Palaeomagnetism shows bauxites and ferricretes to be mid‐Tertiary.  相似文献   

Stratigraphy and tectonics of the Early to Middle Proterozoic transition,Katherine‐El Sherana area,Northern Territory     

R. S. Needham  P. G. Stuart‐Smith 《Australian Journal of Earth Sciences》2013,60(2):219-230

Abstract

Two unconformity‐bound groups of volcanic rocks and associated sediments (El Sherana and Edith River Groups) separate the older Pine Creek Geosyncline metasediments from platform cover of the McArthur Basin. Dominated by intersecting NW and ENE rift systems, the volcanics are genetically related to an extensional tectonic system which was also active during deposition of the Pine Creek Geosyncline sequence. In contrast, the younger platform cover was deposited in a relatively stable environment. The rift valleys were filled with rhyolite flows, ignimbrite and ill‐sorted arenite and rudite, and flyschoid sediments spread onto adjacent lands. Following tight upright folding, granite intrusion and erosion, an extensive ignimbrite sheet (=6000 km²) spread from a centre probably at the intercept of the two rifts. Microgranite at this intersection was possibly emplaced in the evacuated magma chamber. The volcanic sequences were deeply eroded and weathered before platform cover deposition began. The platform sediments, represented in the area by the Kombolgie Formation, were deposited from about 1690 Ma to 1650 Ma, and their base is taken as the closest stratigraphic indicator of the boundary between the Early and Middle Proterozoic.  相似文献   

The MW 6.9 14 April 2010 Yushu Earthquake and a 10,000-Year Record of Paleoseismicity along the Guoqiong Segment of the Yushu Fault,Qinghai Province, China     

Taylor F. ARMSTRONG  Mervin J. BARTHOLOMEW  FENG Lian  LI Dewei  LIU Demin  Tammy RITTENOUR  SUN Guoqiang 《《地质学报》英文版》2013,87(Z1):329-330

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The New Geophysics   总被引：2，自引：0，他引：2  

Stuart Crampin  Yuan Gao 《地学学报》2013,25(3):173-180

New Geophysics of critically microcracked rock is a new understanding of fluid‐rock deformation that matches much of the behaviour of in situ rock observed throughout the Earth's crust and uppermost mantle. The behaviour of rock in New Geophysics: is self‐similar; can be monitored, calculated, predicted, even in principle controlled; prevails in almost all rocks; and has ‘butterfly‐effect’ sensitivity. All of these remarkable features (except controllability) have been observed, in some cases many times. However, New Geophysics is innovative, controversial, and currently “ridiculed” and “violently opposed” (Schopenhauer Stages 1 and 2), and is difficult to get published via consensus‐driven peer‐review. Consequently, in the last 10 years, various aspects of New Geophysics have been published in some 20 different journals and conference proceedings making it difficult to access by the general reader. This review presents a synopsis of what is believed to be a fundamental advance in solid Earth geoscience.  相似文献   

Responding to Emerging Contaminant Impacts: Situational Management          下载免费PDF全文

Suthan S. Suthersan  John Horst  Ian Ross  Erica Kalve  Joseph Quinnan  Erika Houtz  Jeff Burdick 《Ground Water Monitoring & Remediation》2016,36(3):22-32

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Measurement and interpretation of connectivity of Chinese cities in world city network, 2010   总被引：5，自引：3，他引：2  

Ben DERUDDER  Peter J TAYLOR  Michael HOYLER  NI Pengfei  LIU Xingjian  ZHAO Miaoxi  SHEN Wei  Frank WITLOX 《中国地理科学(英文版)》2013,23(3):261-273

This is an empirical paper that measures and interprets the position of Chinese cities in the world city network in 2010. Building on a specification of the world city network as a′interlocking network′in which business services firms play the crucial role in city network formation, information is gathered about the presence of global service firms in cities. This information is converted into data to provide the′service value′of a city for a firm′s provision of corporate services in a 526(cities)×175(firms) matrix. These data are then used as the input to the interlocking network model in order to measure cities′connectivity and its predominant geographical orientation. Here we focus on the position of some key Chinese cities in this regard, and discuss and interpret results in the context of the urban dimensions of the′opening up′of the Chinese economy.  相似文献