监测网顾及灵敏度准则的解析二类设计     

周世健  陈永奇 《测绘工程》1998,7(3):23-28,33

变形体的变形模式确定的情况下,应用灵敏度准则进行监测网的设计;根据Ｔａｙｏｒ展式,导出了监测网顾及灵敏度准则的二类设计模型,并对其解算及模拟算例加以说明。  相似文献   

自动制图综合人工神经元网络方法的研究   总被引：1，自引：1，他引：0  

田震  王家耀  武芳 《测绘学院学报》1998,(4)

现代神经生理学研究表明 ,人脑的大量神经元构成有所分工而又紧密联系的神经元网络 ,它的结构和功能可以采用物理可实现的系统人工神经元网络来模拟。制图综合是人脑神经元网络获取、处理、输出地理信息的复杂视觉思维过程 ,可以用人工神经元网络来模拟。文中探讨了制图综合的人工神经元网络的设计 ,并对用于实现自动制图综合的结果进行分析 ,指出其应用前景。  相似文献   

自由网平差方法及统计特性新探     

王仲锋 《测绘与空间地理信息》1998,(2)

本文结合参数平差和主成分估计理论,导出了误差方程中含多重共线性时未知参数的求解公式,并以定理的形式,证明了主成分估计的解是极小范数解。由此,将主成分估计推广到秩亏网平差中,同时导出了未知参数估值之协因数阵的计算公式,同时,证明了自由网平差的传统特性。  相似文献   

河北省环渤海地区生态经济协调发展的人工神经网络分析   总被引：11，自引：2，他引：9  

李双成  高伟明  刘濂 《地理研究》1998,17(4):352-359

区域社会经济系统的可持续发展依赖于系统成分的协调程度及与生态系统的增益耦合。传统研究多以系统动力学或多目标规划模型来调控系统。文中以人工神经网络模型来模拟和映射社会经济系统的结构和功能。通过构建、训练、测试、运行河北省环渤海地区生态经济网络模型,提出了以减缓发展速度、降低能量投入水平等措施来达到生态系统和社会经济系统协调发展的目标。  相似文献   

Reservoir induced earthquakes analyzed via radial basis function networks     

Ghassem Habibagahi 《Soil Dynamics and Earthquake Engineering》1998,17(1):53-56

Estimation of the magnitude of reservoir induced seismicity is essential for seismic risk analysis of dam sites. Different geological and empirical methods dealing with the mechanism or magnitude of such earthquakes are available in the literature. In this study, a method based on an artificial neural network utilizing radial basis functions (RBF network) was employed to analyze the problem. The network has only two input neurons, one representing the maximum depth of the reservoir and the other being a comprehensive parameter representing reservoir geometry. Magnitudes of the induced earthquakes predicted using the RBF network were compared with the actual recorded data. Compared with the conventional statistical approach, the proposed method gives a better prediction, both in terms of coefficients of correlation and error rates.  相似文献   

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   

The analysis of drainage network composition   总被引：1，自引：0，他引：1  

J. S. Smart 《地球表面变化过程与地形》1978,3(2):129-170

The Horton method of analyzing drainage network composition is reviewed, with the conclusion that it has not been very effective either in improving understanding or in developing useful methods of characterizing drainage basins. New methods which are based on the link rather than the Horton (or Strahler) stream are described. A number of detailed examples of the application of these new methods to the topologic and geometric properties of networks are provided. The results are compared with the predictions of the random model. Data used in the analysis were obtained from 1:24,000 U.S.G.S. topographic maps of eastern Kentucky. Thirty drainage basins were selected and their channel networks were outlined first by the contour-crenulation (CC) method and then by another, more objective, method (SC) in which stream sources were identified by a quantitative slope criterion. The CC and SC samples comprise about 8,700 and 1,700 links, respectively. The three most important results of the analysis are: (1) the channel networks are slightly but significantly more elongated than predicted by the random model, (2) there are fewer second magnitude links than predicted, and (3) the length distribution for interior links depends upon the kind of link (interior or exterior) joined downstream. These features are found in both CC and SC networks.  相似文献   

Applications of the random model of drainage basin composition     

J. S. Smart  C. Werner 《地球表面变化过程与地形》1976,1(3):219-233

The random model of drainage basin composition is founded on the assumptions that (a) natural channels are topologically random in the absence of geological controls and (b) for channel networks developed in similar environments, the exterior and interior link lengths are independent random variables with a common distribution for each type. The effectiveness of this model in estimating the values of geomorphic variables and in explaining and predicting geomorphic relationships is illustrated by several examples. The data required for these examples were obtained from map studies of 30 channel networks, comprising a total of about 8700 links, in eastern Kentucky. A common factor in the success of all three applications of the model is the way in which the planimetric features of drainage basins are determined by their underlying topologic structure.  相似文献   

Prediction of uniaxial compression PFC3D model micro‐properties using artificial neural networks     

A. S. Tawadrous  D. DeGagné  M. Pierce  D. Mas Ivars 《国际地质力学数值与分析法杂志》2009,33(18):1953-1962

Artificial neural networks are used to predict the micro‐properties of particle flow code in three dimensions (PFC3D) models needed to reproduce macro‐properties of cylindrical rock samples in uniaxial compression tests. Data for the training and verification of the networks were obtained by running a large number of PFC3D models and observing the resulting macro‐properties. Four artificial networks based on two different architectures were used. The networks used different numbers of input parameters to predict the micro‐properties. Multi‐layer perceptron networks using Young's modulus, Poisson's ratio, uniaxial compressive strength, model particle resolution and the maximum‐to‐minimum particle ratio showed excellent performance in both training and verification. Adding one more variable—namely, minimum particle radius—showed degrading performance. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

The Coral Triangle Initiative and regional exchanges: Strengthening capacity through a regional learning network     

《Global Environmental Change》2015

Natural resource management and conservation programs that promote building capacity and social learning among participants often lead to the formation of learning networks: a type of social network where learning is both a goal and potential outcome of the network. Through forming relationships and sharing information, participants in a learning network build social capital that can help a network achieve social and environmental goals. In this study, we explored social capital in a learning network that emerged through a large-scale marine governance effort, the Coral Triangle Initiative on Coral Reefs, Fisheries, and Food Security. Through a mixture of social network analysis and key informant interviews, we examined the major patterns of information exchange among individuals who had participated in regional learning exchanges; evaluated whether the network's structure resulted in information sharing; and considered implications for strengthening network sustainability, capacity building, and learning. We found that the Regional Exchange network fostered information sharing among participants across national and organizational boundaries. While the network had individuals who were more central to information sharing, the network structure was generally decentralized, indicating potential resilience to changes in leadership and membership. Participants stressed the importance of the knowledge and connections they had acquired through the learning network; however, they expressed doubts regarding its sustainability and stressed the need for a strong coordinating entity. Our findings suggest that conservation learning networks have the ability to bridge cultural divides and promote social learning; however, a strong network coordinator and continuing efforts to support information sharing and learning are crucial to the network's strength and sustainability. The tangible learning and capacity development outcomes cultivated through Regional Exchange network underscore the value of and need to invest in conservation networks that support peer-to-peer learning.  相似文献