云南地震应急快速评估系统优化研究   总被引：1，自引：1，他引：0  

李敏  许瑞杰  李永强 《震灾防御技术》2018,13(1):177-186

地震应急快速评估系统是各级地震应急指挥技术平台的重要组成部分,自建成以来在全国历次破坏性地震应急处置工作中发挥了突出作用。本文基于现有地震应急快速评估系统,以云南为例,开展了针对评估功能构架和数据传递流程的研究,从软件工程的角度探索能够优化现有系统评估效率的方法,提升了评估产品的产出速度,并通过模拟震例进行技术验证。  相似文献   

基于小比例缩尺模型结构试验的小型钢架反力墙优化设计与力学性能分析     

孙柏涛  姜琪  闫培雷 《震灾防御技术》2018,13(4):869-877

为了降低模型制作加工成本和节约试验空间,开展结构缩尺比例小于1:10的小模型结构抗震试验。目前,国内相关的试验设备较少,本文将参考大型反力墙的结构形式,研究小型钢架反力墙,并对其进行优化设计和力学性能分析,为后续的制作加工提供理论依据。  相似文献   

Grey wolf optimizer: a new strategy to invert geophysical data sets          下载免费PDF全文

Aayush Agarwal  Akash Chandra  Shalivahan Shalivahan  Roshan K Singh 《Geophysical Prospecting》2018,66(6):1215-1226

There is no meta‐heuristic approach best suited for solving all optimization problems making this field of study highly active. This results in enhancing current approaches and proposing new meta‐heuristic algorithms. Out of all meta‐heuristic algorithms, swarm intelligence is preferred as it can preserve information about the search space over the course of iterations and usually has fewer tuning parameters. Grey Wolves, considered as apex predators, motivated us to simulate Grey Wolves in the optimization of geophysical data sets. The grey wolf optimizer is a swarm‐based meta‐heuristic algorithm, inspired by mimicking the social leadership hierarchy and hunting behaviour of Grey Wolves. The leadership hierarchy is simulated by alpha, beta, delta and omega types of wolves. The three main phases of hunting, that is searching, encircling and attacking prey, is implemented to perform the optimization. To evaluate the efficacy of the grey wolf optimizer, we performed inversion on the total gradient of magnetic, gravity and self‐potential anomalies. The results have been compared with the particle swarm optimization technique. Global minimum for all the examples from grey wolf optimizer was obtained with seven wolves in a pack and 2000 iterations. Inversion was initially performed on thin dykes for noise‐free and noise‐corrupted (up to 20% random noise) synthetic data sets. The inversion on a single thin dyke was performed with a different search space. The results demonstrate that, compared with particle swarm optimization, the grey wolf optimizer is less sensitive to search space variations. Inversion of noise‐corrupted data shows that grey wolf optimizer has a better capability in handling noisy data as compared to particle swarm optimization. Practical applicability of the grey wolf optimizer has been demonstrated by adopting four profiles (i.e. surface magnetic, airborne magnetic, gravity and self‐potential) from the published literature. The grey wolf optimizer results show better data fit than the particle swarm optimizer results and match well with borehole data.  相似文献   

基于优化参数的地震P、S波震相到时自动拾取及质量评估   总被引：2，自引：0，他引：2       下载免费PDF全文

杨旭  李永华  苏伟  孙莲 《地球物理学报》2019,62(11):4290-4299

准确拾取P、S波震相到时是深入开展地震波研究工作的基础,本文改进了自动拾取参数优化函数算法和质量评估方案,引入了拾取到时优化方案,使用基于参数优化的频带-带宽拾取算法、AICD拾取算法和峰度拾取算法对腾冲地区7个宽频带地震台站记录的地震资料开展了地震P、S波到时自动拾取,对拾取结果进行了优化和质量判定.结果表明：经参数优化、拾取优化后,采用3种方法自动拾取的P、S波到时与人工拾取到时的时差在0.1 s内的记录占比分别达到74.66%、70.98%.这些参数值均优于算法改进前的同类参数,证明了优化方法的可靠性.  相似文献   

Acquisition design for direct reflectivity and velocity estimation from blended and irregularly sampled data     

Shotaro Nakayama  Gerrit Blacquière  Tomohide Ishiyama 《Geophysical Prospecting》2019,67(8):2127-2146

Blended acquisition along with efficient spatial sampling is capable of providing high-quality seismic data in a cost-effective and productive manner. While deblending and data reconstruction conventionally accompany this way of data acquisition, the recorded data can be processed directly to estimate subsurface properties. We establish a workflow to design survey parameters that account for the source blending as well as the spatial sampling of sources and detectors. The proposed method involves an iterative scheme to derive the survey design leading to optimum reflectivity and velocity estimation via joint migration inversion. In the workflow, we extend the standard implementation of joint migration inversion to cope with the data acquired in a blended fashion along with irregular detector and source geometries. This makes a direct estimation of reflectivity and velocity models feasible without the need of deblending or data reconstruction. During the iterations, the errors in reflectivity and velocity estimates are used to update the survey parameters by integrating a genetic algorithm and a convolutional neural network. Bio-inspired operators enable the simultaneous update of the blending and sampling operators. To relate the choice of survey parameters to the performance of joint migration inversion, we utilize a convolutional neural network. The applied network architecture discards suboptimal solutions among newly generated ones. Conversely, it carries optimal ones to the subsequent step, which improves the efficiency of the proposed approach. The resultant acquisition scenario yields a notable enhancement in both reflectivity and velocity estimation attributable to the choice of survey parameters.  相似文献   

基于两点磁梯度张量的磁性目标在线定位方法          下载免费PDF全文

刘继昊  李夕海  曾小牛 《地球物理学报》2017,60(10):3995-4004

利用磁梯度张量反演磁性目标参数的方法广泛应用于是磁性目标定位,本文提出了一种通过测量两点磁梯度张量对磁性目标进行在线定位的方法.首先利用磁矩指向相同的原则从张量方程的解中得到目标方向,其次利用参数之间的线性关系解算出目标距离,最后利用两点磁感应强度之差,结合Levenberg-Marquardt优化算法对距离做进一步修正.基于所设计的两点张量测量阵列的仿真实验表明:(1)在相同条件下,本文方法定位成功率为64.24%,而2015年吕俊伟改进的STAR方法为59.85%;(2)仪器测量噪声强度达到某一阈值时,一定区域内定位成功率随噪声强度的增加迅速下降;(3)优化算法迭代次数上限取10次即可;(4)其他条件不变时,随着基线长度的增加,定位成功率先升高后降低.  相似文献   

CPU/GPU near real-time preprocessing for ZY-3 satellite images: Relative radiometric correction,MTF compensation,and geocorrection     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

ZY-3 is the first high-accuracy civil stereo-mapping optical satellite of China. It greatly improves China’s optical satellite image resolution with a boom in data volume, calling for new challenges in processing real-time applications. On the other hand, using central processing unit (CPU)/graphic processing unit (GPU) to resolve data-intensive remote sensing problems becomes a hot issue. In this paper, we present an approach for CPU/GPU near real-time preprocessing of ZY-3 satellite images, focusing on three key processors: relative radiometric correction (RRC), modulation transfer function compensation (MTFC), and geocorrection (GC). First, basic GPU implementation issues are addressed to make the processors capable of processing with GPU. Second, three effective GPU specific optimizations are applied for further improvement of the GPU performance. Furthermore, to fully exploit the CPU’s computing horsepower within the system, a CPU/GPU workload distribution scheme is proposed, in which CPU undertakes partial computation to share the workloads of GPU. The experimental result shows that our approach achieved an overall 48.84-fold speedup ratio in ZY-3 nadir image preprocessing (the corresponding run time is 11.60 s for one image), which is capable of meeting the requirement of near real-time response to the applications that follow. In addition, with the supportability of IEEE 754–2008 floating-point standard in the Fermi type GPU, preprocessing ZY-3 images with our CPU/GPU processors could maintain the quality of image preprocess as done traditionally with CPU processors.  相似文献   

CORRESPONDENCE ANALYSIS AND ADSORBATE SELECTION FOR CHEMICAL SENSOR ARRAYS     

FERNANDO AVILA  D.E.MYERS  CHRIS PALMER 《地理学报(英文版)》1991,(5)

Carey et al.utilized principal components analysis (PCA) to analyze frequency shift data obtained frompiezoelectric sensors formed by coating quartz crystals with 27 different GC stationary phases and testedusing 14 analytes.The objective of the analysis was to determine an optimal reduced set of coatings fordetection of the analytes.The results were correlated with those obtained from cluster analysis.In thispaper the data are re-analyzed using correspondence analysis (CA).The advantage of using CA includea symmetric treatment of sensor coatings and analytes and better identification of the representation ofthe analytes in terms of the detection components.The results obtained by the conjunctive use of PCA,a varimax rotation and cluster analysis were obtained by CA.  相似文献   

基于优化随机森林回归模型的土壤盐渍化反演   总被引：1，自引：0，他引：1  

杨练兵  陈春波  郑宏伟  罗格平  尚白军  Olaf Hellwich 《地球信息科学学报》2021,23(9):1662-1674

当前应用于土壤盐分含量（Soil Salinity Content, SSC）反演的随机森林回归（Random Forests Regression, RFR）较少关注对模型精度影响较大的反演参数子集和模型参数的同步优化。本研究选择渭-库绿洲和奇台绿洲为实验区,基于Landsat-5 TM、SRTM、MOD11A2.006遥感数据构建反演参数。首先,利用弹性网络（Elastic Net, EN）筛选出反演参数子集,然后利用遗传算法（Genetic Algorithm, GA）和贝叶斯优化算法（Bayesian Optimization Algorithm, BOA）分别优化随机森林回归（Random Forests Regression, RFR）参数,建立反演参数子集和模型参数分步优化的RFR模型（EN-GA-RFR、EN-BOA-RFR）。建立利用GA和BOA分别同步优化反演参数子集和模型参数的RFR模型（GA-RFR、BOA-RFR）。在每个实验区,对比EN-GA-RFR、EN-BOA-RFR、GA-RFR、BOA-RFR的预测精度。最后分析每个实验区各类盐渍土的空间分布,并对2个实验区的反演参数进行对比分析。结果表明：每个实验区模型预测精度由高到低的排序均为BOA-RFR>GA-RFR>EN-BOA-RFR=EN-GA-RFR,整体上BOA的优化性能均好于GA;渭-库绿洲和奇台绿洲面积占比最大的盐渍土类型分别为盐渍土和中度盐渍土;反演参数对SSC的表征能力存在空间分异性。  相似文献   

Probabilistic analysis of retaining walls     

Ioannis E. Zevgolis  Philippe L. Bourdeau 《Computers and Geotechnics》2010

A methodology for the probabilistic analysis of reinforced concrete cantilever walls is developed and described in this paper. The wall’s external stability under static conditions is addressed and modeled as a series system with correlated failure modes. Computations of reliability are performed using Monte Carlo simulations for assumed probability distributions of the backfill and foundation material engineering properties. A case example is analyzed based on the described methodology. The results indicated that risk, measured by the system probability of failure, is not a linear function of safety ratios. All three safety ratios in question were positively correlated, with bearing capacity being subjected to higher degree of uncertainty. The degree of correlation was found to have an important effect on the system probability of failure. Considering the width of the base as varying design parameter, the study also showed that first-order reliability bounds, which are often applied in practice, may lead to a noteworthy over- or under-estimation of the design.  相似文献