Optimum design of structures against earthquake by wavelet neural network and filter banks     

Eysa Salajegheh  Ali Heidari 《地震工程与结构动力学》2005,34(1):67-82

Optimum design of structures for earthquake is achieved by simulated annealing. To reduce the computational work, a fast wavelet transform is used by means of which the number of points in the earthquake record is decreased. The record is decomposed into two parts. One part contains the low frequency of the record, and the other contains the high frequency of the record. The low‐frequency content is the effective part, since most of the energy of the record is contained in this part of the record. Thus, the low‐frequency part of the record is used for dynamic analysis. Then, using a wavelet neural network, the dynamic responses of the structures are approximated. By such approximation, the dynamic analysis of the structure becomes unnecessary in the process of optimization. The wavelet neural networks have been employed as a general approximation tool for the time history dynamic analysis. A number of structures are designed for optimal weight and the results are compared to those corresponding to the exact dynamic analysis. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Intertidal subsidence and collapse features on wave‐exposed,drift‐aligned sandy beaches subject to Amazon mud: Cayenne,French Guiana     

Edward J. Anthony  Franck Dolique 《地球表面变化过程与地形》2006,31(8):1051-1057

Short‐lived collapse features affecting the intertidal sandy profile were observed on mud‐rich beaches in Cayenne. They were formed in packets of beach sand accumulating over thick (several metres) fluid to under‐consolidated foreshore mud, which adjusts to this sand loading by seaward and longshore migration of fluid mud and subsequent in situ mud dewatering, thus generating subsidence and deformation of the overlying sand sheet. These sandy collapse features required active longshore sand transport and were washed out by wave processes at each rising tide. They finally disappeared permanently as adjustment of the underlying mud enabled stabilization of the beach profile. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Heat exchanges in muddy intertidal sediments: Chichester Harbour,West Sussex,England     

S.J. Harrison 《Estuarine, Coastal and Shelf Science》1985,20(4):477-490

Temperature observations made from a lightweight tower assembly in Chichester Harbour, West Sussex, demonstrate that marked changes in temperature at intertidal mud surfaces occur on a flow tide. The magnitude and direction of these changes are dependent on the external atmospheric and marine conditions, and on the timing of tidal inundation. Calculated heat exchange values for the 3h prior to high water fall into four distinct timing zones. There is a relationship between thermal stress, measured as rate of change of temperature with time, and time of high water. Mud surfaces are net receivers of heat energy from inundating water layers.  相似文献   

Wholesale funding and the increase in construction bank-owned real estate in the US financial crisis     

Elora Raymond 《Urban geography》2017,38(9):1374-1392

The housing crisis left some metropolitan areas littered with partially constructed subdivisions and developments. Most of these failed developments were built by small construction firms reliant on small banks for finance. Failed construction projects became bank-owned real estate (REO), prolonging the crisis and contributing to an uneven recovery. But there is little research on the spatial distribution or financial processes driving construction REO. I use a finance-as-spatial fix theorization to describe increasing interrelation between construction lending and global capital markets through wholesale funding, and the subsequent buildup of construction REO. Wholesale funding allows small banks to access money markets. Controlling for economic growth, the home price bubble, and financial institutions, I use a national panel regression to identify key factors associated with high levels of construction REO in urban areas. Consistent with a finance-as-spatial-fix analysis, the strongest determinant of construction REO was the type of capital flows into small banks.  相似文献   

Coastal morphological modeling to assess the dynamics of Arklow Bank, Ireland     

J. K. PANIGRAHI  P. N. ANANTH  P. A. UMESH 《国际泥沙研究》2009,24(3):299-314

A numerical modeling and simulation experiment is carried out to assess the sediment dynamics of Arklow Bank, Ireland. To meet a requirement for favorable site selection to establish windmills on the bank, the long-term morphological changes of the coast are studied using the CAMS （Coastal Area Morphological Shell） model of the Mike-21 suite of programs. The morphological modeling of the bank was accomplished by pursuing a probabilistic approach for the observed tide and wave characteristics that contribute significantly to the sediment transport processes over the bank. A series of simulations are performed using Mike-21 NSW （Nearshore Spectral Wind-Wave）, HD （Hydrodynamic）, and ST （Sand Transport） models to establish the coastal hydraulics parameters. The results of the morphological modeling showed that generally the bank is dynamically stable with most areas of the bank having average bed level changes on the order of ±8 cm/day.  相似文献   

南黄海辐射沙洲中心沿岸晚更新世以来的沉积环境演变   总被引：5，自引：0，他引：5  

朱晓东  任美锷  朱大奎 《海洋与湖沼》1999,30(4):427-434

对南黄海辐射沙洲中心沿岸地区两个钻孔采用高密度、定量采样方法进行有孔虫和沉积分析。结果表明,该地区晚更新世晚期可能发育了古长江河道、河口、河流边滩或河漫滩以及泛滥平原乃至泛滥湖沼等陆相沉积环境。进入全新世,则先后依次出现了潮滩、河口、潮滩、潮流沙体和潮滩,及至最终成陆。  相似文献   

中国金融包容区域差异：地理包容能否带动业务包容？     

李振发  林文盛  叶雅玲  贺灿飞 《热带地理》2020,40(4):709-720

基于银监会提供的商业银行分支机构地理分布数据，设计计量模型研究了2005—2017年中国金融包容的时空间差异，重点关注在基本实现分支机构城乡全覆盖（地理包容）的前提下，银行是否真正提升金融服务的普及程度，从而带动业务层面的金融包容。结果发现，各类银行分支机构的设立的确提升了民众金融服务使用率，地理包容对业务包容具有促进作用，但不同地区起作用的银行种类差异明显，且各类银行的促进作用也在不同时期显现。研究期内，在东部地区，主要是全国性股份制商业银行和外资商业银行持续地提升了业务层面的金融包容水平；在东北地区，大型国有商业银行和城市商业银行扮演了上述角色，但后者的促进作用略晚于前者出现；在中部地区大型国有商业银行和全国性股份制商业银行起持续性的促进作用；而在西部地区则是大型国有商业银行和农村商业银行的促进效应明显，但后者显现促进作用大幅晚于前者。  相似文献   

西安市银行网点空间集聚性分析   总被引：1，自引：0，他引：1  

秦泗刚  段汉明 《测绘科学》2015,40(7):68-72

针对目前银行空间分布研究多涉及宏观区域尺度,中微观尺度研究明显不足,尤其缺乏从空间认知的角度对城市层面银行网点集聚性和集聚模式的研究的现状,该文以西安市1113个银行网点为研究对象,运用最近邻距离指数、Ripley's K函数、热点探测技术以及标准差椭圆等方法对西安市银行网点空间分布与集聚模式进行了研究。结果显示:西安市银行网点空间分布呈现出集聚分布的特点,随着距离增加,集聚性先增加后减弱;中小尺度层面,形成了多层次的银行集聚区;银行网点空间分布方向性强,大致以钟楼为中心沿东北—西南方向分布。  相似文献   

Stream channels are narrower in pasture than in forest   总被引：1，自引：0，他引：1  

Robert J. Davies‐Colley 《新西兰海洋与淡水研究杂志》2013,47(5):599-608

In the Hakarimata Range, west of Hamilton, New Zealand, second‐order streams appear to be wider in native than in pasture catchments, whereas streams in pine plantations (18 years old) appear to be suffering active stream‐bank erosion. A working hypothesis to explain these observations was that pasture vegetation replacing original forest encroaches on the stream channel, causing it to become narrower. To test the hypothesis, channel widths were measured up stream and down stream of “transitions” from native forest to pasture in 20 streams of different size in marginal ranges of the Waikato Basin. Small streams (catchment area <1 km², width in forest <2 m) were found to be half the width in pasture reaches as in forest. The degree of channel narrowing decreased as stream size increased and was minimal in large streams (catchment area >30 km², width in forest >10 m). This narrowing of stream channels implies that native forest clearance in New Zealand has reduced stream channel habitat. A concern regarding riparian planting for stream restoration is that sediment stored in pasture stream banks could be mobilised if grasses are extinguished by shading, resulting in turbid streamwater and sedimentation of fines in the channel.  相似文献   

塔中上奥陶统台缘礁滩体储层成岩作用及孔隙演化   总被引：5，自引：0，他引：5  

王振宇  严威  张云峰  孙崇浩  张丽娟  邬光辉  韩剑发  申银民 《新疆地质》2007,25(3):287-290

详细阐述了塔中上奥陶统台缘礁滩体主要成岩作用类型及其对礁滩体储层性质的影响,建立了碳酸盐岩成岩和孔隙演化史.方解石胶结作用是破坏孔隙和降低孔隙度的最主要因素,而溶蚀作用和构造破裂作用则是提高储层孔渗性能的极为重要的建设性成岩作用.礁型地貌隆起和海平面相对变化所控制的暴露,以及发育的成岩早期大气淡水溶蚀、淋滤作用和岩溶作用是控制塔中台缘礁滩体优质储层发育的根本原因.储层成岩和孔隙演化模式的建立揭示了孔隙演化的阶段及其独特性,对认识储层特征和进一步勘探均具重要意义.  相似文献