干旱地区灌溉生产函数与经济用水灌溉定额的确定方法探讨   总被引：2，自引：0，他引：2  

张巨俭  郭忠 《中国沙漠》1995,15(4):362-367

本文利用最优化计算方法,分析了干旱地区作物产量与灌溉定额之间的关系,论证了灌溉生产函数的求解与经济用水灌溉定额的确定方法,为灌区计划用水提供科学根据。  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   

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   

Evaluation of polarimetric capabilities of dual polarized Sentinel-1 and TerraSAR-X data to improve the PSInSAR algorithm using amplitude dispersion index optimization     

《International Journal of Applied Earth Observation and Geoinformation》2020

Polarimetric data is an additional source of information in PSI technique to improve its performance in land subsidence estimation. The combination of polarimetric data and radar interferometry can lead to an increase in coherence and the number of PS pixels. In this paper, we evaluated and compared the dual polarized Sentinel-1A (S1A) and TerraSAR-X (TSX) data to improve the PSInSAR algorithm. The improvement of this research is based on minimizing Amplitude Dispersion Index (ADI) by finding the optimum scattering mechanism to increase the number of PSC and PS pixels. The proposed method was tested using a dataset of 40 dual-pol SAR data (VV/VH) acquired by S1A and 20 dual-pol SAR data (HH/VV) acquired by TSX. The results revealed that using the TSX data, the number of PS pixels increased about 3 times in ESPO method than using the conventional channels, e.g., HH, and VV. This increase in S1A data was about 1.7 times in ESPO method. In addition, we investigated the efficiency of the three polarimetric optimization methods i.e. ESPO, BGSM, and Best for the dual polarized S1A and TSX data. Results showed that the PS density increased about 1.9 times in BGSM and about 1.5 times in Best method in TSX data. However, in S1A data, PS density increased about 1.1 times in BGSM. The Best method was not successful in increasing the PS density using the S1A data. Also, the effectiveness of the method was evaluated in urban and non-urban regions. The experimental results showed that the method was successful in significantly increasing the number of final PS pixels in both regions.  相似文献   

Optimization of honeycomb shape for mitigation of flow deficit behind a separation wall     

《Applied Ocean Research》2019

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基于Servlet的企业级地理信息网络发布的开发与实现   总被引：2，自引：0，他引：2  

林文鹏  王长耀  林惠花 《测绘科学》2004,29(5):80-82

地理信息由于其在信息世界中的基础地位,迫切要求实现在Web上发布。Servlet是一种在服务器端开发Web应用的Java技术。通过实例,简要分析了Servlet技术特点及其在构建WebGIS上的优势,并结合MapXtremeJava,以Jbuilder为集成开发工具开发了企业级地理信息发布实例———移动通信网络优化系统。重点阐述了系统设计及实现方法。实践表明,本系统具有开放性、安全性等特点,提供了分布式计算平台架构,可实现对移动通信网络资源的可视化管理。Servlet技术用于构建WebGIS不仅可行,而且大大提高并行访问的速度。  相似文献