Bayesian methods for outliers detection in GNSS time series   总被引：1，自引：0，他引：1  

Zhang Qianqian  Gui Qingming 《Journal of Geodesy》2013,87(7):609-627

This article is concerned with the problem of detecting outliers in GNSS time series based on Bayesian statistical theory. Firstly, a new model is proposed to simultaneously detect different types of outliers based on the conception of introducing different types of classification variables corresponding to the different types of outliers; the problem of outlier detection is converted into the computation of the corresponding posterior probabilities, and the algorithm for computing the posterior probabilities based on standard Gibbs sampler is designed. Secondly, we analyze the reasons of masking and swamping about detecting patches of additive outliers intensively; an unmasking Bayesian method for detecting additive outlier patches is proposed based on an adaptive Gibbs sampler. Thirdly, the correctness of the theories and methods proposed above is illustrated by simulated data and then by analyzing real GNSS observations, such as cycle slips detection in carrier phase data. Examples illustrate that the Bayesian methods for outliers detection in GNSS time series proposed by this paper are not only capable of detecting isolated outliers but also capable of detecting additive outlier patches. Furthermore, it can be successfully used to process cycle slips in phase data, which solves the problem of small cycle slips.  相似文献   

Optimizing landslide susceptibility mapping in the Kongtong District,NW China: comparing the subdivision criteria of factors     

Ge Yan  Xiangang Gui  Yu Xie  Hongliang Zhao 《国际地球制图》2013,28(13):1408-1426

Abstract

The standards applied to reclassify landslide-conditioning factors differ among studies and may change the accuracy of identifying landslide-prone areas. Therefore, we identified two standards per factor (elevation, aspect, slope, proximity to roads and proximity to streams) from the existing literature and set them as predisposing criteria in this paper. In addition to the five factors, lithology represented by types and a landslide inventory map produced from field surveys were also used in mapping. Thirty-two landslide susceptibility maps were generated based on weights-of-evidence and evaluated using the relative operative characteristic method. The results show that the subdivision criteria of factors change the accuracy, with the success rate varying from 84.34% to 87.51%. The map with the highest value captures more landslides in relatively higher susceptibility classes and is therefore considered the optimal one. Ultimately, a simplified mode of combining subdivision criteria is proposed to simplify comparison.  相似文献   

A fiber-section model based Timoshenko beam element using shear-bending interdependent shape function     

Li Ning  Li Zhongxian  Xie Lili 《地震工程与工程振动(英文版)》2013,12(3):421-432

A fiber-section model based Timoshenko beam element is proposed in this study that is founded on the nonlinear analysis of frame elements considering axial,flexural,and shear deformations.This model is achieved using a shear-bending interdependent formulation(SBIF).The shape function of the element is derived from the exact solution of the homogeneous form of the equilibrium equation for the Timoshenko deformation hypothesis.The proposed element is free from shear-locking.The sectional fiber model is constituted with a multi-axial plasticity material model,which is used to simulate the coupled shear-axial nonlinear behavior of each fiber.By imposing deformation compatibility conditions among the fibers,the sectional and elemental resisting forces are calculated.Since the SBIF shape functions are interactive with the shear-corrector factor for different shapes of sections,an iterative procedure is introduced in the nonlinear state determination of the proposed Timoshenko element.In addition,the proposed model tackles the geometric nonlinear problem by adopting a corotational coordinate transformation approach.The derivation procedure of the corotational algorithm of the SBIF Timoshenko element for nonlinear geometrical analysis is presented.Numerical examples confirm that the SBIF Timoshenko element with a fiber-section model has the same accuracy and robustness as the flexibility-based formulation.Finally,the SBIF Timoshenko element is extended and demonstratedin a three-dimensional numerical example.  相似文献   

应用hiTAIL-PCR技术克隆Marinomonas sp. BSi20584菌株β-半乳糖苷酶基因          下载免费PDF全文

周莉莉陈瑞琴  陈秀兰曾胤新 陈波 《极地研究》2013,25(3):249-256

实验使用hiTAIL-PCR（high-efficiency thermal asymmetric interlaced PCR,高效热不对称交错PCR）方法,从海单胞菌Marinomonas sp. BSi20584中克隆β-半乳糖苷酶基因。从GenBank注册的已知β-半乳糖苷酶氨基酸序列出发,设计引物克隆编码β-半乳糖苷酶保守片段的DAN序列;根据Marinomonas sp. BSi20584天然酶N端氨基酸残基测序结果,设计上游引物,保守DNA片段5’端设计下游引物,克隆N端到保守序列之间的DNA片段;将所得的2个DNA片段拼接并命名拼接后的片段为nbs。根据hiTAIL-PCR方法设计引物,染色体步移克隆nbs上下游片段,拼接上下游片段得到全长序列,设计引物扩增全长片段并测序。本文成功克隆了Marinomonas sp. BSi20584菌株β-半乳糖苷酶的编码基因,全长1 971 bp,NCBI比对表明其编码产物为GH-42家族的一个新成员。  相似文献   

整体性治理视角下福建省海洋管理体制改革深化路径          下载免费PDF全文

延子晴  陈莉莉  崔旺来 《海洋开发与管理》2022,39(11):82-89

党的十九届四中全会将深化行政管理体制改革摆在了新时代治国理政的重要位置,成为推进国家治理体系和治理能力现代化需要高度关注的一项研究议题。“深化”是“中国之治”重大命题之下海洋行政管理体制改革的核心要义,改革开放以来,福建省海洋管理体系经历了从海洋分散管理到海洋综合管理,再到海洋管理分散化的过程,多年的改革,使海洋治理的体系和能力得到了一定的提升,但依然面临着因行政管理部门职能设置重叠、行政管理机构设置不统一、管理模式公私关系松散、管理制度约束性不强等引发的海洋管理体制“部门化”“碎片化”的困境,整体性治理则为海洋管理体制改革向纵深推进提供了一个理论视角。基于深化福建省海洋管理体制改革的整体性治理框架,运用整体性治理理念中整合、协同的有益思路,提出福建省要进一步明确海洋行政管理部门职能分工、强化海洋行政管理部门协同执法、构建更加紧密的公私合作海洋管理模式、强化海洋行政管理制度约束力,构建福建省海洋管理体制整体性治理框架,助推福建海洋管理体制改革深化,从而实现海洋管理体系深化之道。  相似文献   

“21世纪海上丝绸之路”风能资源时空变化评估          下载免费PDF全文

周钰淇  崔佳乐  孙博雯  邵莉莉 《海洋气象学报》2022,42(4):11-21

利用1979—2021 年的 ERA5 再分析资料,采用经验正交函数分解法、Mann-Kendall 趋势检验法等统计方法,对“21 世纪海上丝绸之路”相关海区的海表风场与风能密度的空间分布特征、季节变化特征以及长期变化趋势进行分析。结果表明：(1)研究海域风能密度在不同季节表现出很大的空间差异,夏季的阿拉伯海和孟加拉湾,冬季的中国南海,以及全年的热带南印度洋风能资源都极为丰富。(2)研究时段内,中国南海北部及附近海域、阿拉伯海西部、孟加拉湾西部以及热带西北印度洋风能密度等级整体较高。(3)研究海域的风能密度以年变化特征为主,其中中国南海风能密度的季节变幅最大且在春、秋两季表现出明显的转换特征。(4)在研究海区中,结合水深条件与风能密度时空变化特征的评估结果,可以重点关注台湾海峡、吕宋海峡、中南半岛东南沿海、阿拉伯海西部近岸海域及热带西北印度洋近岸大陆架海域风能资源的开发利用,加强其他海域风能资源的储备。此研究可为“21 世纪海上丝绸之路”风能资源的中长期开发规划提供依据。  相似文献   

板内地震填空与断层运动型式          下载免费PDF全文

向宏发  虢顺民 《地震工程学报》1985,7(4):59-68

根据人们对板缘地震填空的认识,本文用震级—断层长度的经验关系式分析了我国郯庐断裂带、张家口—烟台断裂带、鲜水河和塔里木盆地北缘等断裂带的地震活动与地质构造的关系。指出在板块内部同样存在着地震沿带逐渐“填满补齐”的现象。这种地震填空,主要发生在那些扭压型和剪滑型的断裂带上。一个基本连续的活动断裂带是板内地震填空所必需的地质条件。作者认为,板内地震填空与断层现代运动的不同型式(或状态)密切相关。一个活动断裂带由稳滑、相对闭锁到破裂位错正是地震空区形成、发展直至发生大地震的带内地震填空过程,与此相应的应变积累段、闭锁段和释放松动段在地质上的差别是:断面上新沉积物覆盖程度依次减小,断层泥粘结度逐次降低而其厚度依次增厚,因而对于那些全新世以来有过活动而断面上新沉积物覆盖较大的一类活断层尤应引起注意。  相似文献   

Dirac quasinormal modes of the deformed Hořava-Lifshitz black hole spacetime     

Chunyan Wang  Yuanxing Gui 《Astrophysics and Space Science》2010,325(1):85-91

Using the third-order WKB approximation, we evaluate the quasinormal frequencies of massless Dirac field perturbation around a deformed black hole in the Hořava-Lifshitz gravity with coupling constant λ=1. Our result shows that the Hořava-Lifshitz parameter α plays an important role for the quasinormal frequencies and we discuss the variation of quasinormal frequencies with α. Moreover, we find that the massless Dirac field perturbations decay more slowly in the deformed Hořava-Lifshitz gravity.  相似文献   

Numerical Simulation of P-Wave Propagation in Rock Mass with Granular Material-Filled Fractures Using Hybrid Continuum-Discrete Element Method     

Y. L. Gui  Z. Y. Zhao  H. Y. Zhou  W. Wu 《Rock Mechanics and Rock Engineering》2016,49(10):4049-4060

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Variations in the wind‐energy regime of the Taklimakan Desert,central Asia,over the last 700 years as inferred from nebkha sedimentology and chronology     

Xunming Wang  Lili Lang  Ting Hua  Caixia Zhang  Hui Li 《Boreas: An International Journal of Quaternary Research》2014,43(4):882-894

Changes in the wind‐energy environment between AD 1359 and 2010 in the Taklimakan Desert (central Asia) are recorded by the evolution of Chinese tamarisk (Tamarix taklamakanensis) nebkhas. The carbonate component and sedimentological properties of the nebkha excavated during the study, together with AMS ¹⁴C dating control, indicate that significant regional environmental changes have occurred in the central Taklimakan Desert during the last 700 years. The nebkha data presented show that in the periods of AD c. 1480–1560, c. 1640–1690, c. 1760–1820, c. 1860–1930 and c. 1970–1980 the Taklimakan Desert was a relatively high wind‐energy environment. Although changes in the wind‐energy regime in the desert were mainly in phase with fluctuations of the Siberian High, the wind systems and the variations in wind energy exhibit slight differences when compared with the Tarim Basin. Nebkhas that develop in this region originate from the surfaces of mobile dunes or sand sheets, which differs from the origins of nebkhas found in other arid regions of China.  相似文献