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251.
252.
结构平稳随机地震反应时域分析:方法 总被引:3,自引:3,他引:3
给出了三种常用的随机地震地面运动过程模型,即理想白噪声模型、金井清模型、改进金井清模型的相关函数表达式.引入状态向量,在状态空间中建立地震地面运动激励下的结构振动方程,并求解出结构的复模态特性和复模态反应.利用复模态叠加法推导出线性时不变多自由度体系在这三种随机地震动激励下的平稳协方差反应的解析式,可在时域内直接计算结构随机反应的统计特征.该方法物理概念清晰,结论简便明确,可作为实际工程结构平稳随机地震反应的实用分析方法. 相似文献
253.
254.
小块体重的多元线性回归方程在锡铁山铅锌矿床储量计算中的应用 总被引:1,自引:0,他引:1
从锡铁山铅锌矿床小块体重样品原始测定数据入手,运用数学地质中的回归分析,建立了本矿床的小块体重多元线性回归方程,为矿床储量计算提供了科学参数。利用回归方程法计算小块体重进而可以推广到所有贱金属矿床的储量计算中。 相似文献
255.
In several LUCC studies, statistical methods are being used to analyze land use data. A problem using conventional statistical methods in land use analysis is that these methods assume the data to be statistically independent. But in fact, they have the tendency to be dependent, a phenomenon known as multicollinearity, especially in the cases of few observations. In this paper, a Partial Least-Squares (PLS) regression approach is developed to study relationships between land use and its influencing factors through a case study of the Suzhou-Wuxi-Changzhou region in China. Multicollinearity exists in the dataset and the number of variables is high compared to the number of observations. Four PLS factors are selected through a preliminary analysis. The correlation analyses between land use and in-fluencing factors demonstrate the land use character of rural industrialization and urbaniza-tion in the Suzhou-Wuxi-Changzhou region, meanwhile illustrate that the first PLS factor has enough ability to best describe land use patterns quantitatively, and most of the statistical relations derived from it accord with the fact. By the decreasing capacity of the PLS factors, the reliability of model outcome decreases correspondingly. 相似文献
256.
针对解析方法求解半无限含水层井流问题,对直线补给边界附近的井流采用数值方法进行模拟计算,并将两种方法进行比较,数值计算结果表明,存在补给边界时,抽水一定时间以后降深能达到稳定,但仅仅代表观测点处降深达到稳定,而整个渗流场并未达到稳定状态. 相似文献
257.
Having the ability to predict enrollment is an important task for any school’s recruiting team. The purpose of this study
was to identify significant factors that can be used to predict the spatial distribution of enrollments. As a case study,
we used East Tennessee State University (ETSU) pharmacy school, a regional pharmacy school located in the Appalachian Mountains.
Through the application of a negative binomial regression model, we found that the most important indicators of enrollment
volume for the ETSU pharmacy school were Euclidean distance, probability (based on competing pharmacy schools’ prestige, driving
distance between schools and home and tuition costs), and the natural barrier of the Appalachian Mountains. Using these factors,
together with other control variables, we successfully predicted the spatial distribution of enrollments for ETSU pharmacy
school. Interestingly, gender also surfaced as a variable for predicting the pharmacy school’s enrollment. We found female
students are more sensitive to the geographic proximity of home to school. 相似文献
258.
Geoscientific Information Systems (GIS) provide tools to quantitatively analyze and integrate spatially referenced information
from geological, geophysical, and geochemical surveys for decision-making processes. Excellent coverage of well-documented,
precise and good quality data enables testing of variable exploration models in an efficient and cost effective way with GIS
tools. Digital geoscientific data from the Geological Survey of Finland (GTK) are being used widely as spatial evidence in
exploration targeting, that is ranking areas based on their exploration importance. In the last few years, spatial analysis
techniques including weights-of-evidence, logistic regression, and fuzzy logic, have been increasingly used in GTK’s mineral
exploration and geological mapping projects. Special emphasis has been put into the exploration for gold because of the excellent
data coverage within the prospective volcanic belts and because of the increased activity in gold exploration in Finland during
recent years. In this paper, we describe some successful case histories of using the weights-of-evidence method for the Au-potential
mapping. These projects have shown that, by using spatial modeling techniques, exploration targets can be generated by quantitatively
analyzing extensive amounts of data from various sources and to rank these target areas based on their exploration potential. 相似文献
259.
The mean value concept in mono-linear regression of multi-variables and its application to trace studies in geosciences 总被引:1,自引:1,他引:1
A J T JULL 《中国科学D辑(英文版)》2007,50(12):1828-1834
The "mean value concept" in a mono-linear regression of multi-variables is clarified.Its applications to reconstruction of the past 90-year salinity of the sea surface water in Xisha Islands and to tracing the past 80 ka paleo-geomagnetic events from the Luochuan loess 10Be record are introduced in detail,which show the significance and the potential of the "mean value concept" in geoscience research. 相似文献
260.
Non‐linear structural identification problems have raised considerable research efforts since decades, in which the Bouc–Wen model is generally utilized to simulate non‐linear structural constitutive characteristic. Support vector regression (SVR), a promising data processing method, is studied for versatile‐typed structural identification. First, a model selection strategy is utilized to determine the unknown power parameter of the Bouc–Wen model. Meanwhile, optimum SVR parameters are selected automatically, instead of tuning manually. Consequently, the non‐linear structural equation is rewritten in linear form, and is solved by the SVR technique. A five‐floor versatile‐type structure is studied to show the effectiveness of the proposed method, in which both power parameter known and unknown cases are investigated. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献