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941.
Research on the dynamics of landslide displacement forms the basis for landslide hazard prevention. This paper proposes a novel data-driven approach to monitor and predict the landslide displacement. In the first part, autoregressive moving average time series models are constructed to analyze the autocorrelation of landslide triggering factors. A linear ensemble-based extreme learning machine using the least absolute shrinkage and selection operator is applied in predicting the displacement of landslides. Five benchmarking data-driven models, the support vector machine, neural network, random forest, k-nearest neighbor, and the classical extreme learning machine, are considered as baseline models for validating the ensemble-based extreme learning machines. Numerical experiments demonstrated that the proposed prediction model produces the smallest prediction errors among all the algorithms tested. In the second part, parametric copula models are fitted on the predicted displacement, to investigate the relationship between the triggering factors and landslide displacement values. The Gumbel-Hougaard copula model performs best, which indicates strong upper tail correlation between the triggering factors and displacement values. Thresholds for the triggering factors can be obtained by monitoring the landslide moving patterns with large displacement values. The effectiveness and utility of the proposed data-driven approach have been confirmed with the landslide case study in the region of the Three Gorges Reservoir.  相似文献   
942.
During mountainous area construction by long-distance pipe jacking, the pipe stuck encountered. To reveal the cause of the pipe stuck, this paper investigates the pipe surface frictional resistance corresponding to different burial depths and surrounding rock parameters by ADINA finite element analysis. Parameter sensitivity analysis results show that the cohesion effect on the frictional resistance was small, the frictional resistance tended to decrease markedly with the increasing other rock mechanical parameters and the decreasing burial depth and friction coefficient of the pipes. After continuing to consider the prerequisite of simultaneously changing the elastic modulus, internal friction angle and burial depth conditions, a solution of the maximum number of pipes driven by a single intermediate jacking station (IJS) was reduced from 59 to 40 was proposed based on an integration of simulations with the field monitoring results. Finally, the pipe jacking project was successfully completed after adopting the improvement proposals.  相似文献   
943.
The clustering of spatio‐temporal events has become one of the most important research branches of spatio‐temporal data mining. However, the discovery of clusters of spatio‐temporal events with different shapes and densities remains a challenging problem because of the subjectivity in the choice of two critical parameters: the spatio‐temporal window for estimating the density around each event, and the density threshold for evaluating the significance of clusters. To make the clustering of spatio‐temporal events objective, in this study these two parameters were adaptively generated from statistical information about the dataset. More precisely, the density threshold was statistically modeled as an adjusted significance level controlled by the cardinality and support domain of the dataset, and the appropriate sizes of spatio‐temporal windows for clustering were determined by the spatio‐temporal classification entropy and stability analysis. Experiments on both simulated and earthquake datasets were conducted, and the results show that the proposed method can identify clusters of different shapes and densities.  相似文献   
944.
基于地形起伏度的山区人口密度修正——以岷江上游为例   总被引:4,自引:1,他引:3  
刘颖  邓伟  宋雪茜  周俊 《地理科学》2015,(4):464-470
山区人口承载能力评价是山区国土空间管理的基础之一,而准确的人口密度数据是正确评价人口承载能力的基础。传统的人口密度算法并未考虑地形起伏度对人口分布带来的影响,不能客观反映山区人口聚集程度。引入地形起伏度、海拔高度因子,选择岷江上游作为研究区,首先运用GIS技术提取地形起伏度,再运用SPSS软件对人口密度与地形起伏度相关性进行分析,确定县域不同地形起伏度与海拔人居适宜标准,剔除阈值以外不适宜人口聚居的面积,对人口密度进行修正。研究结果表明:1岷江上游人口分布受地形起伏度的影响显著,二者的对数曲线拟合度为0.89,汶川县、茂县、理县、黑水县与松潘县地形起伏度与人口分布的相关性分别为:0.841、0.773、0.643、0.696和0.730;2应用地形起伏度对岷江上游人口密度修正,为真实反映山区人口密度提供了新的考量依据,剔除了人口密度空间噪音,5县地形起伏度与海拔适宜标准分别为:汶川3.2°和3 693 m,茂县4°和4 033 m,理县4.3°和3 790 m,黑水4.4°和3 853 m、松潘4.2°和3 966 m;地形起伏度高值区面积越大,修正前后的人口密度偏差越大,地形起伏度较大的理县和黑水县修正后的人口密度分别提高了7.8倍和5.6倍;地形起伏度较低的汶川县与茂县修正后人口密度仅分别提高2.3倍与2.4倍;3岷江上游人口潜在压力大,不同区域应因地制宜,汶川和茂县采取重点集约发展战略,理县和黑水县采取适度开发战略,松潘县应采取恢复与保护生态策略。  相似文献   
945.
在修正的全局参比价格法基础上,结合非参数DEA-Hybrid模型评测了中国29个省份的要素市场分割水平及要素配置效率,进而构建考虑地理距离与经济规模的综合权重矩阵,利用空间Durbin模型实证分析区域要素市场分割对要素配置效率的影响。研究发现:东部地区的要素市场分割水平相对较低,中部次之,西部最高;要素市场分割将引致要素配置效率扭曲且存在显著的空间溢出效应,适度财政分权能有效抑制要素市场分割引致的要素配置效率扭曲;较高的国有经济占比、产业结构高级化、交通基础设施和外商直接投资能有效改善区域要素配置效率,对外开放的效率改进作用尚不明显。清除地区间要素市场壁垒并充分发挥市场配置资源的决定性作用是提升要素配置效率的着力点。  相似文献   
946.
947.
绿水洞煤矿区位于华蓥山滑脱褶皱带之华蓥山复式背斜中偏北段,晚二叠世成煤盆地同沉积构造控制了煤层的沉积和分布,华蓥山滑脱构造演化及大巴山逆冲推覆叠加作用使得该区煤层赋存形态复杂化,区内北东向褶皱和断裂导致地层陡倾直立至倒转、层位缺失或重复、煤厚减薄或增厚,同时隐伏小断层发育,对煤层开采影响大,建议开展井下物探工作。  相似文献   
948.
Twenty-eight polychlorinated biphenyls (PCB) congeners were measured in surface sediments from Chaohu Lake to assess their characteristics, potential risk, and the correlation with lake trophic status. PCB levels ranged from 11.074 to 42.712 ng g?1 dry weight (d.w.) in the western lake and 2.017 to 20.189 ng g?1 d.w. in the eastern lake. The highest concentrations were found at the sites near the inlets of western lake tributary rivers where big cities and industrial centers are located. Congeners concentrations showed decreasing order of tetra-CB > tri-CB > deca-CB (PCB-209 detected) > penta-CB > hexa-CB > di-CB > hepta-CB > Octa-CB. It indicated that light and heavy Aroclor mixtures were simultaneously used surrounding the lake basin. PCB levels in the western lake are potentially dangerous to humans and the local fauna. There was a significant positive relationship between tetra-CB (one abundant PCB congener) concentration distribution and sediment grain size in the 16–64 μm fraction, whereas a negative correlation was found in the 4–8 μm fraction. Furthermore, PCB distributions were positively correlated with the total organic carbon of sediments and lake trophic status, especially in the more seriously polluted western lake zone. However, the correlation completely disappeared in eastern lake zone. It suggested that PCB contamination might be attributed to industrial wastewaters and domestic sewages from western lake basin, reaching the lake through rivers, rains and floods.  相似文献   
949.
城镇化是一个国家或地区经济发展的必经途径,同时也是衡量某地区经济发展水平的重要标志之一。城镇化进程不仅关系到区域人口、经济和环境的可持续发展,还关系到区域平衡与区域生产效率,以致关系到区域的综合竞争力。利用2001—2011年吐鲁番地区人口、经济、社会和生态方面的相关数据,剖析吐鲁番地区城镇化系统,选出并构建吐鲁番地区人口、经济、社会和生态4个城镇化系统的6个评价指标体系,对指标进行定量分析;计算城镇化4个系统以及城镇化发展水平的综合评价指数及其各系统的协调度,根据各子系统评价指数建立数学模型,分析吐鲁番地区城镇化驱动因子以及制约该地区城镇化进程的影响因素;并推算出吐鲁番地区城镇化的变化和发展趋势。  相似文献   
950.
通过对兴蒙造山带东段小兴安岭-张广才岭地区张家湾岩体石英闪长岩、正长花岗岩进行的锆石LA-ICP-MS U-Pb年龄分析测试、岩石地球化学的各项分析测试,综合分析研究表明,石英闪长岩形成于早侏罗世(176.2±1.8Ma),具浆混花岗岩特点,属壳幔混合成因;正长花岗岩形成于中侏罗世(166±2.2Ma),具"S"型花岗岩的地球化学属性,属壳源熔融成因。结合该区大地构造背景,认为张家湾岩体很可能是环太平洋增生地体的佳木斯板块与西侧的张广才岭地块碰撞造山作用形成。  相似文献   
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