An intelligent agent based on virtual geographic environment system     

Shen Dayong  Lin Hui  Gong Jianhua  Zhao Yibin  Fang Zhaobao  Guo Zhongyang 《地球空间信息科学学报》2013,16(2):113-116

On the basis of previous work, this paper designs an intelligent agent based on virtual geographic environment (VGE) system that is characterized by huge data, rapid computation, multi-user, multi-thread and intelligence and issues challenges to traditional GIS models and algorithms. The new advances in software and hardware technology lay a reliable basis for system design, development and application.  相似文献   

Fast Construction of Global Pyramids for Very Large Satellite Images     

Longgang Xiang  Jing Chen  Jianya Gong  Zhen Zeng 《Transactions in GIS》2013,17(2):282-297

Satellite imagery plays a critical role in recent popular Virtual Globe systems since it delivers spatially‐related information in a direct and intuitive way. A satellite image may be very large in size due to large coverage, high resolution, or both, and therefore the construction of global pyramids, a core data structure of Virtual Globe, will be time‐consuming if designed improperly. This article, based on the idea of divide‐and‐conquer, proposes an efficient algorithm, termed CGP, for the Construction of Global Pyramids, which builds global pyramids with only a single sequential scan of input imagery. By analyzing the space complexity of CGP, the memory‐minimum pyramid level is derived, at which the memory requirement of CGP is minimized to a practical level, even for very large satellite images. This article also discusses a parallel implementation of CGP, which parallelizes the two main actions in CGP, thus further improving the pyramid construction performance. Both theoretical analysis and experimental results show that our approach outperforms other methods and, more importantly, this advantage increases considerably as the size of input imagery increases.  相似文献   

Dynamic shear modulus of undisturbed soil under different consolidation ratios and its effects on surface ground motion   总被引：1，自引：1，他引：0  

Jing Sun  Maosheng Gong  Xiaxin Tao 《地震工程与工程振动(英文版)》2013,12(4):561-568

The dynamic shear modulus for three types of undisturbed soil under different consolidation ratios is presented by using the resonant column test method. Its effects on surface ground motion is illustrated by calculation. The test results indicate that the power function is a suitable form for describing the relationship between the ratio of the maximum dynamic shear modulus due to anisotropic and isotropic consolidations and the increment of the consolidation ratio. When compared to sand, the increment of the maximum dynamic shear modulus for undisturbed soil due to anisotropic consolidation is much larger. Using a one-dimensional equivalent linearization method, the earthquake influence factor and the characteristic period of the surface acceleration are calculated for two soil layers subjected to several typical earthquake waves. The calculated results show that the difference in nonlinear properties due to different consolidation ratios is generally not very notable, but the degree of its influence on the surface acceleration spectrum is remarkable for the occurrence of strong earthquakes. When compared to isotropic consolidation, the consideration of actual anisotropic consolidation causes the characteristic period to decrease and the earthquake influence factor to increase.  相似文献   

芦山地震前后龙门山断裂带南段视应力研究   总被引：1，自引：0，他引：1  

宫悦  龙锋  易桂喜  赵敏  乔慧珍  王宇玺 《震灾防御技术》2013,8(4):389-396

利用四川台网数字地震记录资料,计算了2008年汶川地震之后、2013年芦山地震之前5年内,龙门山断裂带南段ML3.0级以上地震视应力随时间的变化,以及芦山M7.0级地震序列的视应力值及其时空分布特征.结果表明：①从芦山地震之前1年的时间开始,龙门山断裂带南段有视应力的上升过程;②芦山地震余震序列视应力存在几次比较突出的视应力与震级相关性的被打破以及视应力的突降异常,且在震后3个小时之后,视应力即有明显下降的过程;③从归准化的芦山地震序列视应力σapp的空间分布来看,视应力高值区域分布在主震的西南方向和整个余震区东南边缘,并且这两个高视应力区正好分布在该断层面与华南地块紧密接触的边缘;④主震西侧有一片视应力相对较高的区域;⑤主震以北区域的视应力则相对较低.  相似文献   

基于横波射线弹性阻抗的岩性和流体识别研究(英文)     

龚雪萍  张峰  李向阳  陈双全 《应用地球物理》2013,(2):145-156,235

本文推导了关于射线参数的横波(SS)反射系数近似及横波射线弹性阻抗(SREI)表达式。SREI可以写成S-波入射角或者P-波反射角的表达式,分别记作SREIS和SREIP。由井资料计算得到的弹性模型表明SREIP比SREIS及一般的横波弹性阻抗(SEI)具有更强的储层岩性和流体识别能力。Castagna和Smith(1994)收集的25种样本表明大角度SREIP比一般流体因子具有更好的流体识别能力。每个样本包含一组泥岩、含水砂岩和含气砂岩。实际应用也表明,由纵横波阻抗计算得到的大角度SREIP能有效识别致密含气砂岩储层。  相似文献   

Reevaluation of the offset of the Great Wall associated with the ca. M 8.0 Pingluo earthquake of 1739, Yinchuan graben, China     

Aiming Lin  Gang Rao  Jianmin Hu  Wangbin Gong 《Journal of Seismology》2013,17(4):1281-1294

In this study, we reevaluate, based on our investigation, the ground deformation caused around the area of the Great Wall by the ca. M 8 Pingluo earthquake of 1739 along an active fault zone in the Yinchuan graben, on the western margin of the Ordos Block in northern central China. Previous studies have shown that the Great Wall of China was damaged and right-laterally offset by the 1739 M 8 Pingluo earthquake up to ～1.6–2 m, with a 0.1–1.9-m vertical component, at three locations. However, our recent fieldwork and in-situ measurements have shown that the Great Wall was not affected by the ca. M 8 Pingluo earthquake of 1739, as reported previously, but was actually built on preexisting active fault scarps. This study reinterprets the offset of the Great Wall based on these new field observations and attempts to identify the seismogenic source fault that triggered the 1739 Pingluo earthquake. More work is required if we are to better understand the deformation characteristics of the seismogenic source fault and also improve our ongoing assessments of the seismic hazard within the densely populated area of the Yinchuan graben, central China.  相似文献   

Flood frequency under changing climate in the upper Kafue River basin, southern Africa: a large scale hydrological model application   总被引：1，自引：0，他引：1  

Cosmo Ngongondo  Lu Li  Lebing Gong  Chong-Yu Xu  Berhanu F. Alemaw 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(8):1883-1898

The projected impacts of climate change and variability on floods in the southern Africa has not been well studied despite the threat they pose to human life and property. In this study, the potential impacts of climate change on floods in the upper Kafue River basin, a major tributary of the Zambezi River in southern Africa, were investigated. Catchment hydrography was delineated using the Hydro1k at a spatial resolution of 1 km. The daily global hydrological model WASMOD-D model was calibrated and validated during 1971–1986 and 1987–2001 with the simple-split sample test and during 1971–1980 and 1981–1990 with the differential split sample test, against observed discharge at Machiya gauging station. Predicted discharge for 2021–2050 and 2071–2100 were obtained by forcing the calibrated WASMOD-D with outputs from three GCMs (ECHAM, CMCC3 and IPSL) under the IPCC’s SRES A2 and B1 scenarios. The three GCMs derived daily discharges were combined by assigning a weight to each of them according to their skills to reproduce the daily discharge. The two calibration and validation tests suggested that model performance based on evaluation criteria including the Nash–Sutcliffe coefficient, Pearson’s correlation coefficient (r), Percent Bias and R ² was satisfactory. Flood frequency analysis for the reference period (1960–1990) and two future time slices and climate change scenarios was performed using the peak over threshold analysis. The magnitude of flood peaks was shown to follow generalised Pareto distribution. The simulated floods in the scenario periods showed considerable departures from the reference period. In general, flood events increased during both scenario periods with 2021–2050 showing larger change. The approach in our study has a strong potential for similar assessments in other data scarce regions.  相似文献   

Experimental Research on A New Type of Floating Breakwater for Wave-Absorbing and Energy-Capturing     

Huang  Fang-ping  Gong  Kai  Liu  Zuo-shi  Chen  Jun-hua  Huang  Yan-chen 《中国海洋工程》2020,34(6):817-827

China Ocean Engineering - To avoid the damage caused by big wind and wave in cage culture, and to solve the problem of energy supply faced by automatic breeding equipment, a new type of floating...  相似文献   

Model for large strain consolidation with non-Darcian flow described by a flow exponent and threshold gradient     

Xu-Dong Zhao  Wen-Hui Gong 《国际地质力学数值与分析法杂志》2019,43(14):2251-2269

Many pieces of evidence have confirmed that the seepage in fine-grained soils can deviate from traditional Darcy's law that contributes to the consolidation theory. In this paper, a numerical model, referred to as consolidation with non-Darcian flow 2 (CNDF2), is developed for the 1D large strain consolidation of a saturated porous medium with the non-Darcian flow. The algorithm accounts for vertical strain, general constitutive relationships, the relative velocity of the fluid and solid phases, variable compressibility and permeability relation during consolidation, time-dependent loading, and unload/reload effects. Compared with the CS2 model proposed in previous studies, some parts of the CNDF2 model are modified in order to adapt to the non-Darcian flow, especially the equivalent series hydraulic conductivity and fluid flow. The verification examples of the CNDF2 model demonstrate excellent accuracy for both small strain and large strain consolidation. According to the applicable conditions of non-Darcian flow law, the CNDF2 model is most suitable for the fine-grained soil. The development of CNDF2 is first presented, followed by examples to analyze the influences of the non-Darcian flow on the consolidation behavior.  相似文献   

Multiobjective optimization-based design of stabilizing piles in earth slopes     

Huiming Tang  Wenping Gong  Liangqing Wang  C. Hsein Juang  James R. Martin  Changdong Li 《国际地质力学数值与分析法杂志》2019,43(7):1516-1536

Though the technology of using stabilizing piles to prevent landsliding is not new, the design of such piles with a meaningful optimization framework has been rarely reported. In this paper, a multiobjective optimization-based framework for design of stabilizing piles is presented, in which both reinforcement effectiveness and cost efficiency could be explicitly considered. The design parameters considered in the proposed design framework are the pile parameters, including pile diameter, spacing, length, and position, and the design objectives considered are the reinforcement effectiveness and cost efficiency. The design of stabilizing piles is then implemented as a multiobjective optimization problem. In that the desire to maximize the reinforcement effectiveness and that to maximize the cost efficiency are two conflicting objectives, the output of this multiobjective optimization will be a Pareto front that depicts a trade-off between these two design objectives. With the obtained Pareto front, an informed decision regarding the design of stabilizing piles is reached. The effectiveness and significance of the proposed multiobjective optimization-based design framework for stabilizing piles are demonstrated through two illustrative examples: one is the design of stabilizing piles in a one-layer earth slope and the other the design of stabilizing piles in a two-layer earth slope. Further, parametric analyses are conducted to investigate the influences of the pile design parameters on the stability of reinforced slopes.  相似文献