空间数据挖掘中关联规则的支持度和可信度研究     

刘新  刘文宝 《测绘学院学报》2007,(2)

空间数据挖掘中所依赖的空间相关性是由空间关联规则描述的。研究了事务集为粗糙集时空间关联规则支持度和可信度的计算方法;提出了当事务集为粗糙集、空间数据为模糊数据时的模糊粗糙关联规则。同时,推导了空间关联规则的支持度和可信度的变化规律。  相似文献   

Geomagnetic calm intervals and anomalous solar cycle 20     

K. G. Sontakke  N. K. Thakur  G. K. Rangarajan 《Journal of Earth System Science》1982,91(3):235-239

Long period variations in the occurrence of prolonged intervals of calm magnetic field conditions are studied using index Ap of magnetic activity. The solar-cycle variation in occurrence is compared with the sunspot number. Anomalous behaviour for solar cycle 20, observed in other solar parameters, are shown to be manifested in the occurrence frequency of quiet intervals. Spectral characteristics of occurrence indicates a dominant long period variation of about 30 years and a more feeble 11-year oscillation  相似文献   

南海北部海域油气资源调查技术及其应用研究——拖缆及海底地震仪联合勘探观测系统研究     

曾宪军  韦成龙  李福元  翟继锋 《海洋技术学报》2015,34(5):114-118

拖缆与海底地震仪联合勘探技术在野外地震调查中起着举足轻重的作用,特别是对油气资源的地震调查方法的研究。其中对海底地震仪(OBS)的研究能够给深水油气调查提供有力的保障,OBS在海底的布设是联合采集的关键,对OBS观测系统的研究显得尤为重要,关系到OBS采集的野外资料的总体质量和后期解释。因此,通过研究,可以选择设计最佳的观测系统,为联合勘探技术提供基础数据,降低采集费用、提高作业效率。  相似文献   

云南地震动反应谱特性V_(max)/a_(max)值的研究     

肖梅玲  潘文  叶燎原 《地震研究》1999,(1)

本文通过对发生在云南省的澜沧—耿马等几次地震记录的分析,提出了适合云南实际的地震动反应谱特性Ｖｍａｘ／ａｍａｘ值的ｗｅｉｂｕｌ模型,并求出了平均值和标准差,对于样本不足的给出了ｍ,η的置信区间,可为我国、特别是云南省的工程建设提供基础依据。  相似文献   

ANALYSIS OF THE CONFIDENCE INTERVAL OF THE COMPOSITE FAULT PLANE SOLUTION OBTAINED FROM THE GRID SEARCH METHOD: AN EXAMPLE OF SOUTHERN JIANGXI PROVINCE          下载免费PDF全文

WANG Gan-jiao  HU Xing-ping  GAO Wei  CUI Xiao-feng 《地震地质》2018,40(6):1305-1317

In order to quantitatively analyze the reliability of the composite fault plane solution of small earthquakes, the Bootstrap sampling technique is introduced into the grid search method, and the ideas and methods for calculating the confidence interval from the grid search method are proposed initially. There are two sample sets that can represent the characteristics of the composite fault plane solution. One sample set is the optional solutions obtained by the grid search method and the other is obtained by the Bootstrap sampling technique. Then, we calculate the confidence intervals of the two sample sets (P, B and T axis). The research results of tectonic stress field in southern Jiangxi Province are relatively few. In view of such situation, we use the focal mechanism solutions of small earthquakes to calculate and analyze the composite fault plane solution and the confidence interval. This study shows that the confidence interval of the principal stress axis can be obtained well by both of the sample methods. The reliability of the results and the confidence range of the principal stress axis can be better represented by the confidence intervals. The middle principal stress in southern Jiangxi Province is nearly vertical, and the maximum and minimum principal stresses are nearly horizontal. The direction of maximum principal stress is NWW-SEE and that of the minimum principal stress is NNE-SSW. And, the area is in a strike-slip stress regime. The results are consistent with previous studies, and the stress directions obtained by previous researchers are within the confidence interval calculated by this paper.  相似文献   

The effect of temporal sampling intervals on typical human mobility indicators obtained from mobile phone location data     

Zhiyuan Zhao  Zhixiang Fang  Xiping Yang  Fan Zhang 《International journal of geographical information science》2019,33(7):1471-1495

Mobile phone location data have been extensively used to understand human mobility patterns through the employment of mobility indicators. The temporal sampling interval (TSI), which is measured by the temporal interval between consecutive records, determines how well such data can describe human activities and influence the values of human mobility indicators. However, systematic investigations of how the TSI affects human mobility indicators remain scarce, and characterizing those relationships is a fundamental research question for many related studies. This study uses a mobile phone location dataset containing 19,370 intensively sampled individual trajectories (TSI < 5 minutes) to systematically assess the impacts of the TSI on four typical mobility indicators that describe human mobility patterns from different aspects, which are movement entropy, radius of gyration, eccentricity, and daily travel frequency. We find that different TSIs have complex impacts on the values of different mobility indicators. Specifically, (1) coarser TSIs tend to underestimate the values of the four selected indicators with different degrees; (2) the degrees of underestimation vary significantly among users for eccentricity and daily travel frequency but exhibit high inter-user consistency for radius of gyration and movement entropy. The above findings can help better understand the variations among human mobility studies.  相似文献   

考虑不确定度的POT模型在洪水重现期分析中的应用研究     

纪忠华  王璐  路雨 《水文》2017,37(4):6-11

以淮河紫罗山子流域出口日平均流量数据为研究对象,基于超阈值(POT)模型,采用最大似然法估计广义Pareto(GP)分布参数并计算出重现期水平和相应的置信区间范围。拟合优度检验结果显示POT模型在扩大洪水样本提高使用效率的同时,对样本经验点据的适线性也较好。通过对5种时段长度的水文实测流量数据重现期计算发现:实测数据长度对重现期计算结果不确定性有重要影响,在工程水文中推荐选取恰当的置信区间上界作为设计值加以解决。  相似文献   

南海IODP 367-368钻探区深地震探测的OBS站位设计分析     

王强  赵明辉  张佳政  孙龙涛  丘学林 《热带海洋学报》2018,37(1):90-97

借助于国际大洋发现计划平台, 于2017年2月—6月间在南海实施第三次科学钻探(IODP 367-368航次)。海底地震仪(OBS)深地震探测和国际大洋发现计划(IODP)钻探成果相结合, 可以对南海北部洋陆转换带(COT)边界及地质属性的确定提供更好、更全面的深部地质过程解释。文章基于IODP 367-368钻探提出的三种可能设想(下地壳出露、最老洋壳出露、上地幔出露), 分别建立了三种初始速度模型。利用Rayinvr及Tomo2d软件, 对每一种初始模型分别开展了不同OBS间距的射线追踪和走时模拟测试对比, 以及模型的分辨率测试。测试结果表明: OBS间隔为7km比间隔为10km具有更好的射线路径与密度覆盖; 对于上地幔出露模型, 需要足够长的探测测线(>100km), 才能有效得到30km深处信息; 分辨率测试说明, OBS间距需要设置小于或等于7km时, 才能有效分辨20km速度异常体(即模糊带)。  相似文献