一种基于统计的边缘阈值检验新方法     

王文庆  侯本军  支华  龚俊 《地理空间信息》2007,5(1):89-91

提出了建立在统计分析的基础上边缘阈值检验方法,每个像素的阈值由像素所处的梯度矢量的统计特性决定,这些梯度矢量的统计量用来确定边缘像素选取是否合理,从所获得的结果来看,该方法与以往的边缘检测方法不仅是一致的;而且,该方法输入参数值产生的结果比其它几种边缘检测方法更稳定。  相似文献   

Radar measurements of integral parameters of hailstorms used on hail suppression projects     

Viktor Makitov   《Atmospheric Research》2007,83(2-4):380-388

The exact quantitative estimation of hailstorm precipitation intensity, allowing determining successfully the crop hail damage, is extremely necessary while carrying out of programs of experimental researches of the hail clouds as well as at realization of operative projects on hail suppression. On the other hand, the possibility of obtaining a trustworthy information about changes of hailfall intensity during cloud seeding operations enables to judge more objectively about seeding effect and to make a decision about its beginning and termination. Just because of such a parameter, the kinetic energy of hailfalls presents a great interest for the researchers. As it is known, measuring the kinetic energy of hailfalls is carried out both directly by ground network of hailpads, and by radar methods. The accuracy of the radar methods of the hail kinetic energy measurement strongly depends not only on the choice of an optimum formula for calculation but also on the algorithm used for separating hail and rain parts of radar echo and on the way it was used in the hail–rain mixture zone of precipitation.The method of calculating the kinetic energy of the hailfalls, based on empirical dependence of hail probability P_h on a height of a zone of a radar echo with a reflectivity of 45 dBZ above a level of zero isotherm ΔH₄₅, is offered in the given work. The algorithm of separating hail and rain parts of a radar echo and the way it was applied in a hail–rain mixture zone is described. The examples of hail streaks in contours of radar reflectivity and in isopleths of hail kinetic energy obtained using the given algorithm are shown.In Mendoza province (Argentina), a hail suppression project (1993–1997) for the analysis of the vertical structure of a radar echo with Z_max > 45 dBZ, such new parameter is an integral altitude, was used. This dimensionless parameter is most sensitive to such a condition of radar echo when all four contours of increased reflectivity Z₄₅, Z₅₅, Z₆₅, and Z₇₅ synchronously reach the maximal values. The analysis of time distributions of the main radar parameters of hailstorms on a background of values of integral altitude is resulted. It is shown that local hailfall maximum intensities on the ground are observed after the achievement of maximum integral altitude with a certain delay. It enables to predict zones of the greatest hail damage in a mode of radar observation.  相似文献   

对GZRS房产测绘系统分摊模式的探讨     

廖海燕  李军玲 《地理空间信息》2007,5(5):97-99

结合实际工作对广州市房产面积测算目前使用的GZRS绘图系统的分摊模式进行了详细的分析,说明了只有正确理解各个分摊模式的概念,才能使测量成果质量得到保证。  相似文献   

阶差等比数列选取模型算法研究     

毋河海 《武汉大学学报(信息科学版)》2007,32(11):1016-1021

论述了原选取模型控制表生成的数学基础,确立了该数学模型的"阶差等比"实质,生成了更为简洁的算法,并揭示了其内在的构造规律。  相似文献   

A conception of casualty control based seismic design for buildings     

Li-Li Xie  Yu-Hong Ma  Jin-Jun Hu 《Natural Hazards》2007,40(2):279-287

Earthquake disaster is still the number one among all natural disasters, particularly, in terms of destructive power in causing deaths. Can earthquake engineers control seismic casualties through the seismic design of buildings? For this purpose, a conception of casualty control based seismic design is presented and a “two-step decision-making” method is proposed for determining the optimum seismic design intensity (or ground-motion) for controlling both seismic death and economic losses. The key problems in establishing the model are to determine the appropriate socially acceptable level of earthquake mortality and establish the corresponding objective function and /or constraint conditions in determining the optimum seismic design intensity. Ten different grades of socially acceptable mortality are suggested and the final socially acceptable mortality level was proposed for seismic design based on a questionnaire that was distributed nationwide in China. Finally, the method was applied to eight cities with different seismic hazard in China and the effects of various grades of acceptable earthquake mortality on seismic design intensity are analyzed.  相似文献   

四川省汶川县地质灾害的成因及防治对策   总被引：3，自引：0，他引：3  

程思  易加强 《地质灾害与环境保护》2007,18(4):1-6

四川省阿坝州汶川县位于四川盆地西北部,山高谷深,地形切割强烈,地层岩性和地质构造复杂,地质灾害发生频繁,造成损失巨大,成为国民经济和社会发展的重要障碍.本文分析了阿坝州汶川县地质灾害的主要特征及汶川县的地质灾害隐患,划分地质灾害易发区,阐述了汶川县地质灾害的成因,提出汶川县地质灾害防治初步规划建议,提出建立地质灾害信息系统,建立健全群专结合、群测群防的防灾减灾和地质灾害预报预警系统,为汶川县有计划地开展地质灾害防治和合理安排生产建设提供科学依据.  相似文献   

桩基工程施工安全技术措施的实施     

刘长生 《中国煤田地质》2007,19(A01):98-100

桩基工程的投标文件及施工组织设计均要编制安全技术措施，根据钻探施工中有关安全规程，对每一个工程项目，都要建全安全生产责任制，加强上岗人员安全教育，保证在每一道工序开工前，都有详细的施工安全方案和保障措施，并在施工中全面落实，另外施工过程中对安全内容要按规定实行逐级交底。  相似文献   

西藏玉龙斑岩铜钼矿床区域地球化学异常特征和找矿标志   总被引：2，自引：0，他引：2  

刘占元  史长义  刘崇民 《物探化探计算技术》2007,(Z1)

研究了西藏玉龙斑岩铜矿矿床的区域地球化学特征,结合地质条件综合分析了区域地球化学异常分布规律与矿床的关系,提出了地质、地球化学找矿标志。这对玉龙成矿带进一步勘查找矿有一定的意义。  相似文献   

现代地球系统科学——可持续发展战略的科学基础   总被引：9，自引：0，他引：9  

陈之荣 《地球科学进展》1998,13(2):198-203

人类的发展战略正在发生根本性地转变，用可持续发展战略代替以传统工业为基础的发展战略已成为国际社会的共识。讨论了现代地球系统科学及其与可持续发展的关系等问题，认为在现代地球系统演变过程中，全球环境是基础，人类圈为主导；现代地球系统科学是可持续发展战略的科学基础；实施可持续发展战略必须协调人类圈和全球环境的关系等。  相似文献   

松辽盆地南部深部含气性预测研究     

高东 《吉林地质》2003,22(2):41-44

预测松辽盆地南部深部的含油气层,应采用"两部分离法",首先根据测井响应特征,对地震资料进行自然伽马、电阻率、中子孔隙度、密度及波阻抗等属性体反演,确定出地层中的砂岩层,然后,针对这些砂岩层,利用声波测井和中子测井合成ACNL曲线等,并与GR曲线交汇的油气水层识别等技术,准确地识别出含油气砂岩层。  相似文献