Maximum likelihood environmental calibration and the compute program WACALIB a correction     

H.J.B. Birks 《Journal of Paleolimnology》2001,25(1):111-115

A recently discovered error in the part of the computer program WACALIB that implements maximum likelihood (ML) calibration has been discovered and corrected. The new version of WACALIB has been re-run with all the data-sets from which results based on the earlier version of WACALIB had been published. The new results suggest that ML regression and calibration perform as well or even better than weighted averaging (WA), at least when judged by the apparent root mean squared error. Further work involving cross-validation is required to evaluate more fully the relative performance of WA and ML approaches.  相似文献   

气侯时间序列变点的推断     

杨喜寿  杨洪昌 《大气科学》1996,(1)

本文研究时间序列的变点问题。所给出的统计方法可用来推断一个时间序列是否存在变点，存在几个变点以及变点在什么位置。这种统计推断方法可用于气候阶段的划分。  相似文献   

最大熵谱法在华北地震活动幕式结构分析中的应用   总被引：1，自引：0，他引：1  

李文英 《地震》1996,16(2):121-127

应用定性和定量相结合的方法对华北地区第三、第四活动期Ｍ３≥６地震进行幕式结构分析，发现两个活动期的时间进程、应变释放的图象方面比较相似，由此推断第四活动期应变能大释放阶段已过、目前处于调整阶段。估计第四活动期可能持续到２０２０年前后。  相似文献   

Effects　of　magnitude　accuracy　and　complete－ness　data　on　seismic　hazard　parameters     

邵辉成  谢家树  王平  王亚秀 《地震学报(英文版)》1996,9(4):635-644

Ｅｆｆｅｃｔｓｏｆｍａｇｎｉｔｕｄｅａｃｃｕｒａｃｙａｎｄｃｏｍｐｌｅｔｅ┐ｎｅｓｄａｔａｏｎｓｅｉｓｍｉｃｈａｚａｒｄｐａｒａｍｅｔｅｒｓＨＵＩ－ＣＨＥＮＧＳＨＡＯ（邵辉成），ＪＩＡ－ＳＨＵＸＩＥ（谢家树），ＰＩＮＧＷＡＮＧ（王平）ａｎｄＹＡ－Ｘ...  相似文献   

山西地震带历史地震序列的极大熵谱分析     

彭美煊 《内陆地震》1992,6(3):246-251

综述了极大熵谱分析的原理及Burg递推算法,选取应变能∑E_1~(1/2)地震活动度∑A_1为采样序列,对三个时段的资料进行了极大熵谱分析。结果表明;两个序列所得结果较为一致。山西地震带中强震活动和华北中强震活动同步变化,且主要受321年和347年显著周期控制。其35年和66年短周期活动与太阳活动和地球自转31年和60年长周期较接近,表明地震活动在总体上受太阳活动与地球自转速率变化控制,短周期成份反映了发生地震地区应力场能量积累和释放的特点。  相似文献   

An extreme value analysis of the flow of Burbage Brook     

J. H. Barrett 《Stochastic Hydrology and Hydraulics》1992,6(3):151-165

An extreme value analysis of the flow of Burbage Brook is carried out by modelling peaks over a high threshold. The aims are to illustrate recently developed statistical techniques and to report on interesting features of the flow of the brook over a 58-year period. Peak flows are found to show marked seasonal variation and a downward trend. Then-year return level is estimated for various values ofn, and the reliability of the estimates is assessed.  相似文献   

评定设计基准地震动的地震构造法          下载免费PDF全文

潘华  鄢家全 《地震地质》1993,15(4):347-352

阐述了核电厂选址工作中,确定设计基准地震动的“地震构造法”的构成及其基本原则,就其在国际原子能机构(IAEA)颁布的新旧两版“核安全导则”(1979年版、1991年版)中的异同进行了对比分析,并探讨了“地震构造法”在实际工作中存在的问题,以及对它的改进  相似文献   

On solution of the inverse problem for confined aquifer flow via maximum likelihood     

Hugo A. Loaiciga  Miguel A. Mariño 《Mathematical Geology》1986,18(7):677-692

Joint estimation of transmissivity (T) and storativity (S) in a confined aquifer is done via maximum likelihood (ML). The differential equation of groundwater flow is discretized by the finite-element method, leading to equation _t+x _t=u _t. Elements of matrices and , as well as estimated covariance matrix of noise termu _t, are functions of T and S. By minimizing the negative loglikelihood function corresponding to discretized groundwater flow equation with respect to T and S, ML estimators are obtained. The ML approach is found to yield accurate estimates of T and S (within 9 and 10% of their actual values, respectively) and showed quadratic convergence in Newton's search technique. Prediction of aquifer response, using ML estimators, results in estimated piezometric heads accurate to ±0.5 m from their actual, exact values. Statistical properties of ML estimators are derived and some basic results for statistical inference are given.  相似文献   

Modelling peak accelerations from earthquakes   总被引：1，自引：0，他引：1  

Debbie J. Dupuis  Joanna Mills Flemming 《地震工程与结构动力学》2006,35(8):969-987

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

基于TM影像的南京市土地利用遥感动态监测   总被引：13，自引：0，他引：13  

曹雪  柯长青 《武汉大学学报(信息科学版)》2006,31(11):958-961

基于南京市1988年和1998年两期TM影像，首先用辐射水准归一化法将1998年影像校正到1988年影像的辐射水平上，再经过几何校正、训练区纯化等预处理，对两期影像分别用最大似然法进行分类，然后在Arc／Info的GRID模块中编写AML语言，对得到的两期土地利用分类图进行叠置运算，提取出土地利用动态变化信息。分析结果表明，10a间南京市耕地面积大量减少，林地面积有所增加。  相似文献