基于PSO-PP的围岩稳定性评价   总被引：1，自引：0，他引：1  

徐飞  徐卫亚  温森  刘造保  赵延喜 《岩土力学》2010,31(11):3651-3655

围岩的稳定性评价是一个复杂的不确定系统问题。结合投影寻踪方法、粒子群算法和逻辑斯谛曲线函数,建立了围岩稳定性评价的粒子群优化投影寻踪(projection pursuit based on particle swarm optimization,PSO-PP)模型。该模型一方面采用粒子群算法优化投影指标函数及逻辑斯谛曲线函数参数,确保了模型的准确性;另一方面利用逻辑斯谛曲线函数建立投影值与经验等级之间的非线性关系。模型的测试结果显示了良好的精度,实例分析结果与实际状态完全一致,表明该模型在围岩稳定性评价中的可行性和有效性。  相似文献   

吉林延边地区浅成热液金(铜)矿床的~(40)Ar/~(39)Ar激光探针测年与成矿时代讨论          下载免费PDF全文

赵羽军  孙景贵  王清海  门兰静  李怡欣  郭佳  崔培龙 《地学前缘》2010,17(2):156

延边地区是中国东北部陆缘浅成热液金铜矿床发育的地区之一,广泛发育着浅成热液金矿床、中温热液金(铜)矿床和中深成中高温热液富金铜矿床(类斑岩型);富金铜矿床的成矿时代发生在105～102 Ma,为了进一步确定浅成热液金矿床与中深成中高温热液富金铜矿床的成矿动力学背景,采用流体包裹体的~(40)Ar/~(39)Ar激光探针定年法,对该区典型浅成热液金矿床进行了精细的年代学测定,获得刺猬沟金矿床、五星山金矿床和杜荒岭金矿床的脉石矿物石英流体包裹体的~(40)Ar/~(39)Ar等时线年龄分别为(141±7)Ma、(123±7)Ma和(107±6)Ma,其中刺猬沟金矿床((141±7)Ma)和五星山金矿床((123±7)Ma)的脉石矿物石英流体包裹体含有过剩放射性成因~(40)Ar,而杜荒岭金矿床((107±6)Ma)的脉石矿物石英流体包裹体几乎不含或含极少量过剩放射性成因~(40)Ar。结合最新获得的相关地质体的精细年代学成果,认定该区浅成热液金矿床成矿作用均发生在早白垩世晚期,或发生在早白垩世晚期火山喷发、浅成岩浆就位之后,其形成环境与富金铜矿床一致,为古太平洋板块向亚洲大陆正北向俯冲转入Izanagi-Farallon板块西向俯冲的构造转换期。  相似文献   

洞庭盆地中更新世洞庭湖组砾石特征及其意义   总被引：1，自引：0，他引：1  

陈建成  柏道远  李长安  周柯军  黄文义  陈渡平 《华南地质与矿产》2010,(4):16-22

对位于洞庭盆地安乡凹陷东南部的两护村ZKC1孔中更新世洞庭湖组砾石层进行了粒度和砾态的统计分析。结果表明,砾石的粒度变化反映出2个较大尺度的由大→小的旋回,早旋回由洞庭湖组下段砂砾层组成,晚旋回由洞庭湖组中段上部的砂砾层组成,反映出中更新世早-中期安乡凹陷的两次由慢→快的幕式沉降过程。在上述2个大的粒度旋回之上,叠加有多个更小尺度的砾石粗、细变化,主要与气候干湿的频繁波动有关。洞庭湖组中段顶部砾石的磨圆度明显偏低,反映其沉积时期盆地沉降和周缘隆起区抬升活动的增强。  相似文献   

城市元胞自动机扩展邻域效应的测量与校准研究   总被引：3，自引：1，他引：2  

廖江福  唐立娜  王翠平  许通 《地理科学进展》2014,33(12):1624-1633

城市元胞模型由于在定量分析与预测城市动态的潜力而受到众多研究者的持续关注.邻域规则是主导城市元胞模型模拟过程的关键组件.研究表明,不同土地利用组合间存在显著的邻域效应,且邻域效应具有惯性、排斥和吸引等影响.然而,传统城市元胞模型主要考虑的是特定分辨率下较小窗口的邻域范围.本文尝试刻画更大窗口的邻域效应及其对元胞模型的影响.基于测量的扩展邻域因子,应用粒子群优化算法校准大窗口邻域规则,并创建了考虑扩展邻域效应的城市元胞模型.为验证模型有效性,将其应用于模拟厦门市1995-2010年期间的城市扩张动态.与3×3摩尔邻域的逻辑回归模型相比较,1995-2010年期间的建设用地模拟精度从80.7％提高到83.9％,总体精度从87.8％提高到89.6％,Kappa系数从70.0％提高到74.5％,表明考虑扩展邻域效应的城市模型取得了更好的模拟效果.  相似文献   

Geospatial spreadsheets with microscale air quality visualization and synchronization for supporting multiple-scenario visual collaboration     

Seung Man An  Ho-Young Lee  Byungsoo Kim  Chae-Yeon Yi  Jeong-Hee Eum 《International journal of geographical information science》2014,28(12):2511-2532

A major obstacle of the interdisciplinary communications for decision-making is that each participant prefers the solution from their own area because current collaboration systems cannot effectively mediate among many alternatives. If a visual collaboration system could display multiple alternatives in a single visual presentation, users would be able to compare alternatives with only a few variables, where all other parameters are fixed, at least from a visual perspective. In this study, we developed a visualization tool to support a microscale air quality (MSAQ) management group, the members of which often need to compare the effects of many alternative control methods. The main achievements of this study are: (1) three-dimensional (3D) visualization of the MSAQ using a 3D city model and (2) development of a geospatial spreadsheet (GS) to facilitate visual comparisons, thereby improving decision-making by making it easy to compare differences based on realistic visual display items. A questionnaire-based survey showed that use of the GS could generate a shared perspective and provide a spatiotemporal context for the participants, thereby making it easy to compare, mediate and reach decisions when confronted with many alternatives.  相似文献   

Research on the critical conditions for clay particle release during saline aquifer freshening process     

Xilai Zheng  Ran Chen 《中国海洋大学学报(英文版)》2014,13(4):628-636

Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.  相似文献   

湛江地区一次冷锋型海雾微物理特征   总被引：1，自引：1，他引：0       下载免费PDF全文

吕晶晶  牛生杰  赵丽娟  张羽  徐峰 《大气科学学报》2014,37(2):208-215

利用2010年3月31日—4月2日冷锋天气系统影响下湛江海雾综合观测资料,分析了海雾的微物理特征及海雾过程中气溶胶粒子谱的演变特征。结果表明,海雾的生消与风场密切相关,海雾生成和发展与较强的ESE气流相联系,而弱的NE气流则会促使海雾减弱或消散。湛江海雾的雾滴数浓度为100~102cm-3,液态含水量为0.001~0.232 g·m-3,雾滴平均半径小于10μm,雾滴峰值半径多位于1.4μm。海雾雾滴谱分布以单调递减谱为主,谱宽超过20μm,且雾发展过程中雾滴谱谱宽存在突然增宽和迅速减小的现象。海雾过程中雾滴数浓度的变化主要是由半径小于5μm的雾滴数密度变化引起的。海雾过程对气溶胶粒子的湿清除效果并不显著,雾过程中粒径小于0.1μm和大于4μm的气溶胶粒子数密度显著减少,但在雾消散后又迅速恢复到雾发生前的水平。  相似文献   

海底双相随机介质声反射的SVM神经网络分类识别研究     

尤加春  李红星 《海洋学报》2014,36(3):134-142

考虑海底沉积介质为双相介质,为了更好地模拟实际海底底质的不均匀性,将随机介质理论引入双相介质理论。首先,通过基于随机-双相介质理论的高阶有限差分数值技术模拟计算海底底质分别为泥质砂、泥、泥质砾时的地震反射波信号。然后利用小波变换分别求取不同底质的一次反射波的包络作为其特征向量,最后利用基于粒子群智能算法优化的支持向量机神经网络对这些反射波信号进行分类识别。为了进一步考察所用方法的抗噪能力,对正演得到的海底底质反射波信号分别加入10%、30%、50%的高斯白噪音之后再进行分类,支持向量机仍然取得了较好的分类预测效果。基于上述正演模拟及分类识别方法的论证,提出了一套行之有效的微机软件模拟海底沉积物分类识别的一般化流程,这将有利于开展海底沉积物反射特征的进一步研究。  相似文献   

中国南海区1992-2012年的中尺度涡旋演化过程表达与统计分析     

杜云艳  易嘉伟  吴笛  贺志刚  王东晓  梁福源 《海洋学报(英文版)》2014,33(11):36-47

Automated identification and tracking of mesoscale ocean eddies has recently become one research hotspot in physical oceanography. Several methods have been developed and applied to survey the general kinetic and geometric characteristics of the ocean eddies in the South China Sea（SCS）. However, very few studies attempt to examine eddies＇ internal evolution processes. In this study, we reported a hybrid method to trace eddies＇ propagation in the SCS based on their internal structures, which are characterized by eddy centers, footprint borders, and composite borders. Eddy identification and tracking results were represented by a GIS-based spatiotemporal model. Information on instant states, dynamic evolution processes, and events of disappearance, reappearance, split, and mergence is stored in a GIS database. Results were validated by comparing against the ten Dongsha Cyclonic Eddies（DCEs） and the three long-lived anticyclonic eddies（ACEs） in the northern SCS, which were reported in previous literature. Our study confirmed the development of these eddies. Furthermore, we found more DCE-like and ACE-like eddies in these areas from 2005 to 2012 in our database. Spatial distribution analysis of disappearing, reappearing, splitting, and merging activities shows that eddies in the SCS tend to cluster to the northwest of Luzon Island, southwest of Luzon Strait, and around the marginal sea of Vietnam. Kuroshio intrusions and the complex sea floor topography in these areas are the possible factors that lead to these spatial clusters.  相似文献   

基于PIV技术不同形式防波堤周围涡旋场特性研究(英文)     

郄禄文  夏乾  张翔  蒋学炼 《海洋通报(英文版)》2014,(2)

深水防波堤周围流场存在复杂的紊动变化,防波堤较容易发生失效破坏。本文利用PIV技术,基于模型实验,对规则波作用下防波堤周围的速度流场及其涡流特性进行了实验研究,获得了规则波流场的瞬时速度分布。通过对不同型式防波堤在不同的水力条件下的波浪流场实验数据的分析,定量地研究了防波堤堤身水域的涡旋流场的水力特性。  相似文献