Textural segmentation of digital rock images into bedding units using texture energy and cluster labels     

Stefan M. Luthi 《Mathematical Geology》1994,26(2):181-196

The texture of digital rock images, as recorded, for instance, with borehole imaging devices, is shown to reflect different bedding types. Textural segmentation of borehole images, therefore, subdivides the recorded sequence into bedding units. We show that a textural segmentation algorithm based on the concept of texture energy achieves good results when compared with synthetic as well as real data in which petroleum geologists have performed zonations on cores. Texture energy involves filtering of the original image with a set of texture sensitive masks. The filtering is done as a finite convolution over the size of the masks. On the resulting images the variance is computed over a relatively large sliding window, which, in its practical implementation, covers the full width of the image. The resulting nine one-dimensional curves are then clustered hierarchically into a user-determined number of image texture or lithological bedding classes. Principal component analysis previous to clustering can be used to reduce redundancy in the data. A recurring and relatively ill-defined problem in this field are macro-textures, i.e., the cyclic interbedding of two or more bedding types. We show that sliding Fourier transforms and variable mask scale can successfully address the zonation of macro-textures. In general, the method gives best results with mask sizes equivalent to 2–4 centimeters, reflecting the length scale at which the investigated geological bedding seems to have its highest variation.  相似文献   

MRI分割的几何活动轮廓模型的半隐式AOS迭代方法     

李刚 《南京气象学院学报》2005,28(2):225-232

几何活动轮廓模型以其计算稳定等优点，被广泛用于图像分割。给出一种基于AOS(additive operator splitting)算法的快速活动轮廓模型，将AOS方法与几何活动轮廓模型相结合构造一种半隐式迭代模型，它对迭代步长没有限制，从而可以选择较大的迭代步长，提高了模型的时间效率，并使用区域信息构造系数矩阵，使模型具有全局性。对MR(magnetic resonance)图像分割的实验表明，该模型可以得到较好的分割结果，同时时间效率也有大幅提高，方便了实时应用。  相似文献   

航空影像分割的最小二乘支持向量机方法   总被引：5，自引：0，他引：5  

徐芳  梅文胜  张志华 《武汉大学学报(信息科学版)》2005,30(8):694-698

将最小支持向量机LS-SVM用于航空影像的分割,讨论了不同核函数对分割结果的影响和稀疏化处理对决策函数的影响。试验表明了LS-SVM方法用于航空影像分割的可行性。  相似文献   

Labour markets in transition. The experiences of women in two border regions of East Germany     

Bettina van Hoven  Carmella Pfaffenbach 《GeoJournal》2002,56(4):261-269

The political turning point in the former GDR and the transformation processes that have been observed since then have significantly affected economic and social structures in the new Federal States. Gender roles, however, were subjected to even more dramatic changes. Whilst many women experienced the employment policies of the GDR era as beneficial, social researchers often designate them as the losers of unification nowadays. This is largely because the abundance of State support measures for employed women and mothers has been drastically reduced and women as a group have been hit hardest by the crisis on the East German labour market. Using two cases (Mecklenburg-Westpommerania and Thuringia), this paper aims to illustrate the impact of the transformation process on the everyday (working) lives of women. We are particularly concerned with a comparative analysis of how women experience and deal with regional disparities in East Germany. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A rifted inside corner massif on the Mid-Atlantic Ridge at 5°S     

T. J. Reston  W. Weinrebe  I. Grevemeyer  E. R. Flueh  N. C. Mitchell  L. Kirstein  C. Kopp  H. Kopp  participants of Meteor / 《Earth and Planetary Science Letters》2002,200(3-4):255-269

The structure of the Mid-Atlantic Ridge at 5°S was investigated during a recent cruise with the FS Meteor. A major dextral transform fault (hereafter the 5°S FZ) offsets the ridge left-laterally by 80 km. Just south of the transform and to the west of the median valley, the inside corner (IC – the region bounded by the ridge and the active transform) is marked by a major massif, characterized by a corrugated upper surface. Fossil IC massifs can also be identified further to the west. Unusually, a massif almost as high as the IC massif also characterizes the outside corner (OC) south of the inactive fracture zone and to the east of the median valley. This OC massif has axis-parallel dimensions identical to the IC massif and both are bounded on their sides closest to the spreading axis by abrupt, steep slopes. An axial volcanic ridge is well developed in the median valley both south of the IC/OC massifs and in an abandoned rift valley to the east of the OC massif, but is absent along the new ridge-axis segment between the IC and OC massifs. Wide-angle seismic data show that between the massifs, the crust of the median valley thins markedly towards the FZ. These observations are consistent with the formation of the OC massif by the rifting of an IC core complex and the development of a new spreading centre between the IC and OC massifs. The split IC massif presents an opportunity to study the internal structure of the footwall of a detachment fault, from the corrugated fault surface to deeper beneath the fault, without recourse to drilling. Preliminary dredging recovered gabbros from the scarp slope of the rifted IC massif, and serpentinites and gabbros from the intersection of this scarp with the corrugated surface. This is compatible with a concentration of serpentinites along the detachment surface, even where the massif internally is largely plutonic in nature.  相似文献   

中国市场群落发展机制   总被引：13，自引：1，他引：13  

石忆邵 《地理学报》2002,57(3):356-364

市场群落的崛起已成为21世纪初中国市场经济发展的新景观，在概述市场群落的基本特点后，揭示其形成和演化的动力机制；继而对单个市场与群落型市场上经营者的行为方式特征进行了比较分析，表明群落型市场具有多方面的竞争优势；指出市场群落的空间扩张还促进了经济国际化与本地化的有机融合发展，同时认为，市场群落持续发展的根本在于保证商人的可持续发展，并提出了相应的对策建议。  相似文献   

新疆入境旅游市场竞争态分析   总被引：10，自引：2，他引：10  

李景宜 《干旱区地理》2003,26(1):64-67

提出旅游业市场竞争态模型，运用此模型可以定量分析、对比旅游市场的现实竞争状态，在此基础上，进行市场研究，确定本地区在旅游高超中的地位，明确现在和未来市场竞争的优势和劣势，为地区旅游业发展规划提供参考依据。应用这一模型，分析了新疆入境旅游的客源市场竞争态及省内各地区目的地市场竞争态。  相似文献   

我国入境旅游的特点和发展趋势分析   总被引：18，自引：0，他引：18  

徐正林 《世界地理研究》2003,12(3):98-105

入境旅游人数以及旅游(外汇)收入是衡量一个国家旅游实力和开放程度的重要指标。本文在回顾中国入境旅游发展历史的基础上，通过对我国20多年入境旅游方面有关指标的分析总结了我国入境旅游具有增长的持续性、波动性和阶段性，入境旅游发展的脆弱性和集中性等特点。针对入境旅游未来的发展趋势提出加快我国入境旅游发展的建议。  相似文献   

Sectoral Shifts and Occupational Migration in the United States     

Mark E. Reisinger 《The Professional geographer》2003,55(3):383-395

This research is grounded in notions of differential economic restructuring across employment sectors and geographic space, as well as migration selectivity by occupation. A series of unconstrained competing‐destinations models were employed to analyze the response by workers in thirteen occupational categories to sectoral employment change, average wages, and distance. As was hypothesized, workers in occupations that require high levels of education and skills are more responsive, in terms of migration, to economic opportunities in alternative labor‐market areas. However, the results do not support the hypothesis that highly educated and skilled workers migrate longer distances. Further investigation suggests that opportunities for highly educated and skilled workers may be clustering in relatively few areas that are in relatively close proximity.  相似文献   

资源性(矿产)资产的市场运作与贵州经济发展     

冯爱国 《贵州地质》2003,20(2):121-125

该文以产权理论、价值理论为基础，阐述了资源性资产市场化运作的条件、方式和必要性、现实性，提出了建设和完善贵州资源性资产市场的相关政策建议。  相似文献