从瞬变电磁场到波场的优化算法   总被引：9，自引：5，他引：4       下载免费PDF全文

李貅  薛国强  宋建平  郭文波  武军杰 《地球物理学报》2005,48(5):1185-1190

在波场的正变换中,保证瞬变电磁场的计算精度的同时,应用两步最优化算法,成功地控制和减少了积分系数个数和离散数字积分的采样点个数,解决了在波场反变换式中,由于积分系数过多而产生的欠定方程组的问题,同时改善了第一类算子方程的不适定性.在波场反变换中,将正则化算法用于逆变换过程的计算中,通过采用偏差原理和Newton迭代格式选出最优的正则化参数,使得反变换所得到的波场稳定、可靠.通过对数值计算结果与已知波场函数对比,证明了该方法的有效性和实用性.  相似文献   

Investigation on the energy absorption performance of a fixed-bottom pressure-differential wave energy converter     

《Applied Ocean Research》2017

In this article, we investigate the energy absorption performance of a fixed-bottom pressure-differential wave energy converter. Two versions of the technology are considered: one has the moving surfaces on the bottom of the air chambers whereas the other has the moving surfaces on the top. We developed numerical models in the frequency domain, thereby enabling the power absorption of the two versions of the device to be assessed. It is observed that the moving surfaces on the top allow for easier tuning of the natural period of the system. Taking into account stroke limitations, the design is optimized. Results indicate that the pressure-differential wave energy converter is a highly efficient technology both with respect to energy absorption and selected economic performance indicators.  相似文献   

The role of observations in the inverse analysis of landslide propagation     

《Computers and Geotechnics》2017

Model calibration is usually based on trial-and-error procedures that, in turn, rely on expert judgment or previously acquired experiences for similar phenomena. Efficient and reliable procedures for model calibration of the propagation stage of landslides are still needed. This paper addresses this issue by proposing an inverse analysis procedure and applying it to the case history of a short run-out landslide triggered by a rising perched water table after a heavy rainfall. It focuses on the key role played by the field observations used to set up the inverse analysis, and evaluating the reliability of the numerical simulations. It also investigates the effect of different types of optimization parameters on the inverse analysis results, referring to a mixed-phase model or to a two-phase model for the propagating soil. Several sets of observations are used; all of them refer to the soil deposit thickness at the end of propagation, but differ in both location and number of the adopted values. The numerical analysis of the case history is performed through the academic “GeoFlow_SPH” model, and model calibration by inverse analysis is conducted using the “UCODE” software. The results obtained are discussed with the aim to provide practical criteria to identify the minimum amount of information required for a satisfactory model calibration.  相似文献   

核磁共振共轭梯度解谱方法研究   总被引：1，自引：1，他引：0       下载免费PDF全文

李鹏举  宋延杰  俞军  田宏娟  仲从存 《地球物理学进展》2010,25(2):590-595

核磁共振（NMR）解谱技术是核磁共振资料应用的基础和关键.本文将核磁共振解谱的混定线性反演问题转化为求目标函数极小值的最优化问题,然后利用共轭梯度算法具有二次终止性、收敛速度快的特点解决上述最优化问题.将该方法应用于无噪声和不同信噪比的理论数据解谱以及岩心NMR实验解谱并与真谱及实验室国外软件解谱结果对比表明：在信噪比SNR≥5时解谱结果和真谱符合得很好,谱线光滑连续;随着信噪比的降低对初始点的要求随之提高;两块岩心解谱结果与实验室结果符合得很好,利用解谱结果计算的核磁孔隙度与实验室氦孔隙度绝对误差分别为0.78%和0.57%.因此,本文方法有效、实用,具有较强的抗噪能力,对初始点的要求不高,能够应用于生产和科研实践中.  相似文献   

共反射面元叠加的应用实践   总被引：19，自引：5，他引：14       下载免费PDF全文

杨锴  王华忠  马在田 《地球物理学报》2004,47(2):327-331

共反射面元（Common Reflection Surface）叠加是一种不依赖于宏观速度模型的零炮检距剖面成像方法,实现共反射面元叠加依赖于3个波场属性参数的确定,它们分别是零偏移距射线的出射角α、Normal波和Normal Incident Point波出射到地表的波前曲率半径RN和RNIP. 在CRS叠加的理论基础上,本文阐述如何在实际数据上实现CRS叠加. 首先,通过简洁的一维相关性分析在常规叠加剖面上找到对应该共反射面元的一组初始波场属性参数(α,RN,RNIP),然后在对应的叠前数据上应用最优化算法对这组参数进行优化处理,相比初始属性参数,优化后的属性参数能够更好地聚集来自地下反射层的能量,最后应用优化后的属性参数实现最优CRS叠加.  相似文献   

青海省地震局网络优化及技术应用     

孙凯 《高原地震》2008,20(3):60-64

通过对青海省地震局已建成的互联网络中存在的若干问题,提出对现有网络进行优化和改造的思路,旨在提高网络的传输性能和工作效率。  相似文献   

A decision support system for floating platform design     

J. Vasconcellos 《Ocean Engineering》1999,26(9):865

This paper describes a methodology developed for the preliminary design of floating production platforms. The preliminary design approach interlinks the mathematical design model with global optimization techniques. To illustrate the design procedure, the initial intermediate and final results are presented. They provide a clear understanding of the mathematical model and the decision support system. The preliminary design approach described here is based on the commercial software which is interfaced to what is called the FPS system and linked to a SEARCH package for design solutions. The paper summarizes the preliminary design approach, the mathematical model optimization and presents semisubmersible and TLP platform examples.  相似文献   

Assessment and prioritization of soil erosion triggering factors using analytical hierarchy process and Taguchi method   总被引：1，自引：0，他引：1  

Mehdi Hayatzadeh  Vahid Moosavi  Ramyar Aliramaee 《国际泥沙研究》2023,38(3):396-404

The main aims of this study are assessing some factors which affect the soil erosion process and evaluating the results of an analytical hierarchy process(AHP) method using the Taguchi method. Firstly, the weights for those factors and levels affecting soil erosion were determined by the AHP method. The determination of weights was based on the opinions of academic researchers, experts, middle managers,and members of the Soil and Water Research Centers in Iran. Secondly, an L32 Taguchi orthogona...  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   

PLS RESPONSE SURFACE OPTIMIZATION:THE CARSO PROCEDURE     

SERGIO CLEMENTI  GABRIELE CRUCIANI  GIANLUCA CURTI  BERT SKAGERBERG 《地理学报(英文版)》1989,(2)

The paper presents a procedure to obtain response surfaces with non-designed data.The method is basedon PLS modelling of the expanded X-matrix followed by transformation of the PLS loadings intopolynomial coefficients and detection of the co-ordinates of the best response within the experimentaldomain.The results are presented both graphically and numerically.The procedure is validated on anoptimization study of the yield of an organic reaction.  相似文献