基于多源遥感数据的高山峡谷区岩性信息提取研究——以新疆乌什县北山1:50000填图试点为例     

孟鹏燕  孙杰  于长春  穆超  帅爽  谢菲  孟丹 《地质力学学报》2016,22(4):907-920

新疆乌什县北山1:50000填图试点项目位于塔里木盆地西北边缘和西南天山交接部位,海拔较高,地形切割较深,属于典型的高山峡谷区。利用ASTER、SPOT6、GF-2等多源遥感数据,基于典型岩性光谱吸收特征,进行岩性差异信息增强与提取研究,总结出一套基于多源遥感数据进行岩性单元边界划分的方法。以ASTER数据、ASTER与SPOT6协同数据、ASTER与GF-2协同数据等为基础影像数据,并选择最佳波段组合进行RGB彩色合成,从而增强影像差异,结合已有研究区地质资料,初步圈定不同影像单元边界;继而利用矿物丰度指数、SMACC端元丰度提取等方法识别研究区内主要岩性的分布位置和范围;最后结合野外实际调查数据,依据实际地质背景和影像质量进行筛选,获得最终的岩性单元解译图。研究结果为该区进一步进行地层优化划分及对比提供了参考资料。   相似文献   

Authorship,Collaboration, and Gender: Fifteen Years of Publication Productivity in Selected Geography Journals     

Lesley S. Rigg  Shannon McCarragher  Andrew Krmenec 《The Professional geographer》2013,65(4):491-502

In academia, publication productivity, defined as the number of peer-reviewed articles published and the frequency of citations, is a primary factor in the assessment of tenure and promotion. One of the most cited gender differences in academia is the “productivity puzzle,” which suggests that women publish less than men, thereby affecting every aspect of a woman's academic career. Peer-reviewed articles published in the Annals of the Association of American Geographers (Annals) and The Professional Geographer (PG) between 1995 and 2006, and in four subdisciplinary journals between 2005 and 2009, as well as citation reports, were used to explore whether gender differences are present in publication productivity. Gender differences were evident in the proportion of women authors, the frequency of collaboration, and the number of citations across a broad range of prestigious geographic journals. For all journals studied, women were underrepresented, especially in the authorship positions that equate to notions of respect and merit. Although the number of collaborative articles increased during the study period, single-authored papers are the dominant mode of publication for both men and women for most geographic journals. The authorship patterns for frequently cited articles generally mirror those for all articles. Because the frequency of collaborative publication was high for women, the dual trends of a general increase in publication collaboration and increasing participation of women in academic geography bodes well for increased female productivity as it relates to publishing. Nevertheless, it is important to note that, currently, males as lead or single authors represent the predominant voice of geography within the journals examined in this study.  相似文献   

A Review of: “Applications of Spatial Data Structures: Computer Graphics,Image Processing,and GIS”. By H. SAMET. (Addison-Wesley Publishing Company,Inc, 1989.) [Pp. xv + 507; figures,tables, appendix,references, name and credit index,subject index.] Price US $49.95. ISBN 020150300 X (hardback).     

WOLFGANG KAINZ 《International journal of geographical information science》2013,27(2):253-254

The introduction of automated generalisation procedures in map production systems requires that generalisation systems are capable of processing large amounts of map data in acceptable time and that cartographic quality is similar to traditional map products. With respect to these requirements, we examine two complementary approaches that should improve generalisation systems currently in use by national topographic mapping agencies. Our focus is particularly on self‐evaluating systems, taking as an example those systems that build on the multi‐agent paradigm. The first approach aims to improve the cartographic quality by utilising cartographic expert knowledge relating to spatial context. More specifically, we introduce expert rules for the selection of generalisation operations based on a classification of buildings into five urban structure types, including inner city, urban, suburban, rural, and industrial and commercial areas. The second approach aims to utilise machine learning techniques to extract heuristics that allow us to reduce the search space and hence the time in which a good cartographical solution is reached. Both approaches are tested individually and in combination for the generalisation of buildings from map scale 1:5000 to the target map scale of 1:25 000. Our experiments show improvements in terms of efficiency and effectiveness. We provide evidence that both approaches complement each other and that a combination of expert and machine learnt rules give better results than the individual approaches. Both approaches are sufficiently general to be applicable to other forms of self‐evaluating, constraint‐based systems than multi‐agent systems, and to other feature classes than buildings. Problems have been identified resulting from difficulties to formalise cartographic quality by means of constraints for the control of the generalisation process.  相似文献   

Three‐dimensional modal pushover analysis of buildings subjected to two components of ground motion,including its evaluation for tall buildings     

Juan C. Reyes  Anil K. Chopra 《地震工程与结构动力学》2011,40(7):789-806

The modal pushover analysis (MPA) procedure, presently restricted to one horizontal component of ground motion, is extended to three‐dimensional analysis of buildings—symmetric or unsymmetric in plan—subjected to two horizontal components of ground motion, simultaneously. Also presented is a variant of this method, called the practical modal pushover analysis (PMPA) procedure, which estimates seismic demands directly from the earthquake response (or design) spectrum. Its accuracy in estimating seismic demands for very tall buildings is evaluated, demonstrating that for nonlinear systems this procedure is almost as accurate as the response spectrum analysis procedure is for linear systems. Thus, for practical applications, the PMPA procedure offers an attractive alternative whereby seismic demands can be estimated directly from the (elastic) design spectrum, thus avoiding the complications of selecting and scaling ground motions for nonlinear response history analysis. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Changes of Late Mesozoic Tectonic Regimes around the Ordos Basin (North China) and their Geodynamic Implications   总被引：4，自引：0，他引：4  

ZHANG Yueqiao  SHI Wei  DONG Shuwen 《《地质学报》英文版》2011,85(6):1254-1276

A synthesis is given in this paper on late Mesozoic deformation pattern in the zones around the Ordos Basin based on lithostratigraphic and structural analyses. A relative chronology of the late Mesozoic tectonic stress evolution was established from the field analyses of fault kinematics and constrained by stratigraphic contact relationships. The results show alternation of tectonic compressional and extensional regimes. The Ordos Basin and its surroundings were in weak N-S to NNE-SSW extension during the Early to Middle Jurassic, which reactivated E-W-trending basement fractures. The tectonic regime changed to a multi-directional compressional one during the Late Jurassic, which resulted in crustal shortening deformation along the marginal zones of the Ordos Basin. Then it changed to an extensional one during the Early Cretaceous, which rifted the western, northwestern and southeastern margins of the Ordos Basin. A NW-SE compression occurred during the Late Cretaceous and caused the termination of sedimentation and uplift of the Ordos Basin. This phased evolution of the late Mesozoic tectonic stress regimes and associated deformation pattern around the Ordos Basin best records the changes in regional geodynamic settings in East Asia, from the Early to Middle Jurassic post-orogenic extension following the Triassic collision between the North and South China Blocks, to the Late Jurassic multi-directional compressions produced by synchronous convergence of the three plates (the Siberian Plate to the north, Paleo-Pacific Plate to the east and Lhasa Block to the west) towards the East Asian continent. Early Cretaceous extension might be the response to collapse and lithospheric thinning of the North China Craton.  相似文献   

中国“四极”区域旅游合作发展模式研究     

徐淑梅  王烨  崔磊 《世界地理研究》2011,20(2):90-96

在区域旅游合作内容与方式不断发生变革的今天,“中国四极”区域旅游合作框架的提出可谓是一种全新的构想,其不仅可对“四极”地区各自独特的旅游资源进行有效的整合,进而形成既内容丰富又极具特色的完整的旅游品牌;同时这种基于大尺度空间及时间背景下的合作也必然会带来其与相关线路、相关区域之间的旅游协作,从而带动更大区域范围内旅游业的发展。本文从中国“四极”合作开发的可行性分析入手,探讨了中国“四极”合作的发展模式、合作内容和运行机制等方面的问题。  相似文献   

Artificial neural network model for prediction of rock properties from sound level produced during drilling     

《Geomechanics and Geoengineering》2013,8(1):53-61

In many rock engineering applications such as foundations, slopes and tunnels, the intact rock properties are not actually determined by laboratory tests, due to the requirements of high quality core samples and sophisticated test equipments. Thus, predicting the rock properties by using empirical equations has been an attractive research topic relating to rock engineering practice for many years. Soft computing techniques are now being used as alternative statistical tools. In this study, artificial neural network models were developed to predict the rock properties of the intact rock, by using sound level produced during rock drilling. A database of 832 datasets, including drill bit diameter, drill bit speed, penetration rate of the drill bit and equivalent sound level (L_eq) produced during drilling for input parameters, and uniaxial compressive strength (UCS), Schmidt rebound number (SRN), dry density (ρ), P-wave velocity (V_p), tensile strength (TS), modulus of elasticity (E) and percentage porosity (n) of intact rock for output, was established. The constructed models were checked using various prediction performance indices. Goodness of the fit measures revealed that recommended ANN model fitted the data as accurately as experimental results, indicating the usefulness of artificial neural networks in predicting rock properties.  相似文献   

The pattern,evolution, and mechanism of venture capital flows in the Guangdong-Hong Kong-Macao Greater Bay Area,China     

Wu  Kangmin  Wang  Yang  Zhang  Hong’ou  Liu  Yi  Ye  Yuyao  Yue  Xiaoli 《地理学报(英文版)》2022,32(10):2085-2104

Journal of Geographical Sciences - As an important innovation flow, venture capital has been examined in urban network research. However, the segmentation of capital categories and the cross-scale...  相似文献   

Kinematic transformations for planar multi‐directional pseudodynamic testing     

Oya Mercan  James M. Ricles  Richard Sause  Thomas Marullo 《地震工程与结构动力学》2009,38(9):1093-1119

The pseudodynamic (PSD) test method imposes command displacements to a test structure for a given time step. The measured restoring forces and displaced position achieved in the test structure are then used to integrate the equations of motion to determine the command displacements for the next time step. Multi‐directional displacements of the test structure can introduce error in the measured restoring forces and displaced position. The subsequently determined command displacements will not be correct unless the effects of the multi‐directional displacements are considered. This paper presents two approaches for correcting kinematic errors in planar multi‐directional PSD testing, where the test structure is loaded through a rigid loading block. The first approach, referred to as the incremental kinematic transformation method, employs linear displacement transformations within each time step. The second method, referred to as the total kinematic transformation method, is based on accurate nonlinear displacement transformations. Using three displacement sensors and the trigonometric law of cosines, this second method enables the simultaneous nonlinear equations that express the motion of the loading block to be solved without using iteration. The formulation and example applications for each method are given. Results from numerical simulations and laboratory experiments show that the total transformation method maintains accuracy, while the incremental transformation method may accumulate error if the incremental rotation of the loading block is not small over the time step. A procedure for estimating the incremental error in the incremental kinematic transformation method is presented as a means to predict and possibly control the error. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

基于agent的地学协同工作模型     

戚铭尧  励惠国  何建邦  池天河  李家齐 《地球信息科学学报》2007,9(3):85-90

地学协同工作是指群体在一定的环境下(比如地图、虚拟现实空间等)通过相互协作来解决与地学相关的问题,论文首先对地学协同工作及其协作模型的研究现状进行了简单综述,然后提出了基于agent的地学协同工作模型,这种模型以计算主体作为协作过程的最小分解单元,用agent对这种计算主体进行封装,论文阐述了这种协作模型的总体结构和各agent的内部结构,最后对模型的可用性进行了评价。  相似文献