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1.
Considering the fact that there is only one pair of fixed potential poles in one direction used to monitor the resistivity changes under the observatory station which may indicate process of earthquake preparation, based on the precondition that the resistivity structure is 1-dimensional under the observatory station, and by way of equivalent model put forward by the authors, this paper suggests a kind of method trying to separate the resistivity changes in deep layers from that of the shallow layer. Analysis shows that, to obtain the same measured data with the same array, any a multi-layered geo-electrical structure can be equivalently taken as a two-layered one, we call it equivalent model. In this paper, the resistivity and thickness of the upper layer of the equivalent model are equal to that of the first layer of the original one, the resistivity of the lower layer of the equivalent model is obtained with calculation according to the requirement of equivalence, its value is relevant with the resistivities and thicknesses of all layer of the original model except for the first one, so the resistivity change of the equivalent layer can indicate the synthetic effect of variation of all layers of the original model except for the first one. The primary research results show that this method can work well. Foundation item: Chinese Joint Seismological Science Foundation (100146).  相似文献   
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3.
Systematic researches to the clastic reservoirs in various types and various geological ages basins in China indicate that the present burial depth of deep buried clastic eureservoir ranges from 3000 to 6000 m,and its geological ages from Paleozoic,Mesozoic to Cenozoic. It mainly deposited in delta (including braid delta,fan delta,normal delta),river,also shore,shallow lake,gravity flow channel and turbidity fan facies. The quartzose sandstone is the main reservoir rock of deep-buried clastic eureservoir in the shore facies in Paleozoic,but the arenite and arkose sandstones are the main reservoir rock types in delta,river,shallow lake and gravity flow facies in Mesozoic and Cenozoic. The porosity of most of deep-buried clastic eureservoir is more than 10% and permeability more than 10×10?3 μm2. The forma-tion of the deep-buried eureservoir was related to the paleotectonics,paleotemperature,sedimentary environment,the deep dissolution caused by organic acid or carbonic acid,burial style,the abnormal high pore fluid pressure,early hydrocarbon charging,gyprock sealing,hot convective fluid flow and the mode of sand-mud interbedded,etc. The paleotectonics controls the burial style of sandstones,and the paleotemperature controls the diagenesis process. The sedimentary environment is the precondi-tion and foundation,the dissolution is the direct reason to generate the deep buried clastic eureservoir. The abnormal high pore fluid pressure,gyprock sealing,the mode of sand-mud interbedded,early hy-drocarbon charging and the structure fractures were the assistant factors of generating the deep buried clastic eureservoir.  相似文献   
4.
深基坑工程变形预报神经网络法的初步研究   总被引:33,自引:0,他引:33  
孙海涛  吴限 《岩土力学》1998,19(4):63-68
提出了深基坑变形预报的人工神经网络法,详细介绍了该方法的建模和应用实例。预报结果与实测值较为吻合,从而表现在深基坑工程中利用该方法进行变形预报是可行的。  相似文献   
5.
《The Journal of geography》2012,111(5):189-197
Abstract

Illustrated Dictionary of Place Names: United States and Canada. By Kelsie B. Harder. New York: Van Nostrand, 1976. Pp. xiv + 631, $18.95.

Middle America: Its Lands and Peoples. 2nd ed. By Robert C. West and John P. Augelli. Englewood Cliffs, N.J.: Prentice-Hall, 1976. Pp. xvii + 494, $14.95.

Contemporary Africa: Geography and Change. Edited by C. Gregory Knight and James L. Newman. Englewood Cliffs, N.J.: Prentice-Hall, 1976. Pp. xiv + 546, $14.95.

Atlas of Mexico. By Stanley A. Arbingast et al. 2nd ed. Austin, Tex.: Bureau of Business Research, University of Texas, 1975. Pp. ix + 165, $15.00.

Readings in Social Geography. Edited by Emrys Jones. London: Oxford University Press, 1975. Pp. 328, $18.50 and $6.95.

California: Patterns on the Land. 5th ed. By Robert Durrenberger and Robert Johnson. A California Council for Geographic Education Publication. Palo Alto, Calif.: Mayfield Publishing, 1976. Pp. viii + 134, $6.95.

Studying China in Elementary and Secondary Schools, Studying India in Elementary and Secondary Schools, and Studying Japan in Elementary and Secondary Schools. By Leonard S. Ken-worthy. World Affairs Guides. New York: Teachers College Press, 1975. Pp. 68, iii + 67, and iii + 65, $2.75 each.

World Regional Geography: A Question of Place. By Paul Ward English and James Andrew Miller. Harper &; Row Series in Geography. New York: Harper &; Row, 1977. Pp. xiii + 591, $15.95.

Census Data: Geographic Significance and Classroom Utility. Edited by Borden D. Dent. Tualatin, Oreg.: Geographic and Area Study Publications, 1976. Pp. ix + 277.

The Middle East: A Geographical Study. By Peter Beaumont, Gerald H. Blake, and Malcolm J. Wagstaff. London: John Wiley &; Sons, 1976. Pp. xvii + 572, $25.50 and $14.95.

Man's Economic Environment. By Edgar C. Conklingand Maurice Yeates. New York: McGraw-Hill Book Co., 1976. Pp. xi + 308, $11.95.

Applied Climatology: An Introduction. 2nd ed. By John F. Griffiths. New York/London: Oxford University Press, 1976. Pp. xiii + 136, $9.00.

Man and the Environment: Regional Perspectives. Edited by J. H. Holmes. Hawthorn, Victoria: Longman Australia Pty Limited, 1976. Pp. vi + 261, $7.95.

Introduction to Cultural Geography. 5th ed. By Henry M. Kendall, Robert M. Glendinning, Clifford H. MacFadden, and Craig H. MacFadden. New York: Harcourt Brace Jovanovich, 1976. Pp. xx + 449, $12.95.

Interpretation of Aerial Photographs. 3rd ed. By Thomas Eugene Avery. Minneapolis, Minn.: Burgess Publishing Company, 1977. Pp. xi + 392, $14.95.

Geography of the U.S.S.R. 3rd ed. By Paul Lydolph. New York: John Wiley &; Sons, 1977. Pp. xi + 495, $18.95.  相似文献   
6.
基于支持向量机的GNSS时间序列预测   总被引:1,自引:0,他引:1       下载免费PDF全文
在深度学习的理论框架下,针对预测全球卫星导航系统(GNSS)时间序列,传统的经验风险最小化预测模型误差大精度低,泛化性能差且对历史数据的经验依赖大的问题.提出一种采用结构风险最小化原则的基于支持向量机(SVM)的时间序列预测模型.通过和多层的BP神经网络预测模型预测效果比较,结果证明SVM预测模型拥有更好的时间序列预测效果.  相似文献   
7.
Geophysical data sets are growing at an ever-increasing rate, requiring computationally efficient data selection(thinning)methods to preserve essential information. Satellites, such as Wind Sat, provide large data sets for assessing the accuracy and computational efficiency of data selection techniques. A new data thinning technique, based on support vector regression(SVR), is developed and tested. To manage large on-line satellite data streams, observations from Wind Sat are formed into subsets by Voronoi tessellation and then each is thinned by SVR(TSVR). Three experiments are performed. The first confirms the viability of TSVR for a relatively small sample, comparing it to several commonly used data thinning methods(random selection, averaging and Barnes filtering), producing a 10% thinning rate(90% data reduction), low mean absolute errors(MAE) and large correlations with the original data. A second experiment, using a larger dataset, shows TSVR retrievals with MAE < 1 m s-1and correlations 0.98. TSVR was an order of magnitude faster than the commonly used thinning methods. A third experiment applies a two-stage pipeline to TSVR, to accommodate online data. The pipeline subsets reconstruct the wind field with the same accuracy as the second experiment, is an order of magnitude faster than the nonpipeline TSVR. Therefore, pipeline TSVR is two orders of magnitude faster than commonly used thinning methods that ingest the entire data set. This study demonstrates that TSVR pipeline thinning is an accurate and computationally efficient alternative to commonly used data selection techniques.  相似文献   
8.
Cloud Masking is one of the most essential products for satellite remote sensing and downstream applications. This study develops machine learning-based (ML-based) cloud detection algorithms using spectral observations for the Advanced Himawari Imager (AHI) onboard the Himawari-8 geostationary satellite. Collocated active observations from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) are used to provide reference labels for model development and validation. We introduce both daytime and nighttime algorithms that differ according to whether solar band observations are included, and the artificial neural network (ANN) and random forest (RF) techniques are adopted for comparison. To eliminate the influences of surface conditions on cloud detection, we introduce three models with different treatments of the surface. Instead of developing independent ML-based algorithms, we add surface variables in a binary way that enhances the ML-based algorithm accuracy by ~5%. Validated against CALIOP observations, we find that our daytime RF-based algorithm outperforms the AHI operational algorithm by improving the accuracy of cloudy pixel detection by ~5%, while at the same time, reducing misjudgment by ~3%. The nighttime model with only infrared observations is also slightly better than the AHI operational product but may tend to overestimate cloudy pixels. Overall, our ML-based algorithms can serve as a reliable method to provide cloud mask results for both daytime and nighttime AHI observations. We furthermore suggest treating the surface with a set of independent variables for future ML-based algorithm development.  相似文献   
9.
Grid pattern recognition in road networks using the C4.5 algorithm   总被引:1,自引:0,他引:1  
Pattern recognition in road networks can be used for different applications, including spatiotemporal data mining, automated map generalization, data matching of different levels of detail, and other important research topics. Grid patterns are a common pattern type. This paper proposes and implements a method for grid pattern recognition based on the idea of mesh classification through a supervised learning process. To train the classifier, training datasets are selected from worldwide city samples with different cultural, historical, and geographical environments. Meshes are subsequently labeled as composing or noncomposing grids by participants in an experiment, and the mesh measures are defined while accounting for the mesh’s individual characteristics and spatial context. The classifier is generated using the C4.5 algorithm. The accuracy of the classifier is evaluated using Kappa statistics and the overall rate of correctness. The average Kappa value is approximately 0.74, which corresponds to a total accuracy of 87.5%. Additionally, the rationality of the classifier is evaluated in an interpretation step. Two other existing grid pattern recognition methods were also tested on the datasets, and comparison results indicate that our approach is effective in identifying grid patterns in road networks.  相似文献   
10.
深海沉积物分类与命名的参数指标和主成分分析   总被引:1,自引:0,他引:1  
对于南海中部(118个表层沉积物样,水深82~4 420 m)、东部(106个表层沉积物样,水深700~4 508 m)海域的表层沉积物的粒度资料按小于200 m,200~2 000 m,大于2 000 m水深段对水深、平均粒径、黏土含量进行统计分析,结果表明从陆架到陆坡再到深海,平均粒径和黏土含量随水深增加呈非常有规律的变化;把大于2 000 m水深区域再细分为大于2 500 m,大于3 000 m,大于3 500 m,结果表明平均粒径和黏土含量随水深增加几乎无变化,在南海中部水深大于2 000 m海域平均粒径为3.39~3.54μm,黏土平均含量为54.91%~55.47%;在南海东部水深大于2 000 m海域平均粒径为3.25~3.37μm,黏土平均含量为53.91%~54.56%。研究表明2 000 m水深具有划分深海沉积物的指示意义。南海中部水深大于2 000 m海域黏土平均含量为55.19%,平均粒径为3.39μm;在南海东部水深大于2 000 m海域黏土平均含量为53.91%,平均粒径为3.37μm;在南海中部、东部水深大于2 000 m海域平均粒径均小于4μm,黏土平均含量均大于50%,表明深海沉积物粒度特征是平均粒径小于4μm和黏土平均含量大于50%。黏土含量是非生物组分的代表和划分深海沉积物类型的一个独立参数,钙质生物和硅质生物组分是另外两个独立参数。南海东部海域表层沉积物中55种元素总含量为47.50%,硅、铝、钛、钠、钾、磷、钙、镁、铁、锰十种主元素含量为47.03%,其他45种元素含量为0.47%,虽然沉积物来源复杂、成因不同,但沉积物化学主成分并不复杂,主要由前10种主元素和氧元素组成。沉积物主元素铝、钙、硅分别富集于黏土、钙质沉积、硅质沉积中。通过建立沉积物生源组分与碳酸钙、三氧化二铝、二氧化硅的量化关系,可把碳酸钙、生物二氧化硅作为钙质生物和硅质生物的两个替代参数。  相似文献   
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