关于非齐次马氏链的强极限定理     

刘杰  纪灵军  梁佩佩 《成都信息工程学院学报》2009,24(1)

主要研究了非齐次马氏链的强极限定理.首先应用鞅差序列收敛定理给出了关于非齐次马氏链的任意k元函数一类平均值的极限定理.最后得到一系列相关状态序偶出现频率的推论.  相似文献   

几种非线性滤波算法的性能比较与分析          下载免费PDF全文

余春平  李广云  张冠宇 《海洋测绘》2008,28(6):43-45

在非线性状态估计中,传统的扩展卡尔曼滤波通过线性化来实现高斯近似,由于截断误差的存在很难保证估计精度;而基本粒子滤波容易出现粒子退化,导致滤波发散。针对粒子滤波的两个基本假设：蒙特卡罗假设和重要采样假设,采用蒙特卡罗随机链的方法来提高粒子的多样性,并利用无味卡尔曼滤波来产生更高精度的替代分布,发展了无味粒子滤波。通过仿真实验证明,相比较扩展卡尔曼滤波和基本粒子滤波,改进后的无味粒子滤波算法性能更优越,对含有非线性非高斯的状态估计问题有更好的滤波效果。  相似文献   

Mining transition rules of cellular automata for simulating urban expansion by using the deep learning techniques   总被引：3，自引：0，他引：3  

Jialv He  Yao Yao  Ye Hong  Zhang Jinbao 《International journal of geographical information science》2018,32(10):2076-2097

Along with the gradually accelerated urbanization process, simulating and predicting the future pattern of the city is of great importance to the prediction and prevention of some environmental, economic and urban issues. Previous studies have generally integrated traditional machine learning with cellular automaton (CA) models to simulate urban development. Nevertheless, difficulties still exist in the process of obtaining more accurate results with CA models; such difficulties are mainly due to the insufficient consideration of neighborhood effects during urban transition rule mining. In this paper, we used an effective deep learning method, named convolution neural network for united mining (UMCNN), to solve the problem. UMCNN has substantial potential to get neighborhood information from its receptive field. Thus, a novel CA model coupled with UMCNN and Markov chain was designed to improve the performance of simulating urban expansion processes. Choosing the Pearl River Delta of China as the study area, we excavate the driving factors and the transformational relations revealed by the urban land-use patterns in 2000, 2005 and 2010 and further simulate the urban expansion status in 2020 and 2030. Additionally, three traditional machine-learning-based CA models (LR, ANN and RFA) are built to attest the practicality of the proposed model. In the comparison, the proposed method reaches the highest simulation accuracy and landscape index similarity. The predicted urban expansion results reveal that the economy will continue to be the primary factor in the study area from 2010 to 2030. The proposed model can serve as guidance in urban planning and government decision-making.  相似文献   

基于多目标遗传算法和FLUS模型的西北农牧交错带土地利用优化配置   总被引：1，自引：0，他引：1  

杨露  颉耀文  宗乐丽  邱天  焦继宗 《地球信息科学学报》2020,22(3):568-579

西北农牧交错带生态环境脆弱,区位特殊性和生态重要性使其在我国社会经济发展和生态环境保护方面具有重要战略意义。通过对该区域进行土地利用优化配置,使有限的土地资源支撑起生态环境保护和经济发展的重任是本文的出发点。多目标遗传算法和FLUS模型的应用可以从多方面（数量结构、空间布局、综合效益）完善土地利用优化配置,为土地利用优化配置提供更多的选择方案。本文选用多目标遗传算法和FLUS模型对该区域进行2025年的土地利用变化模拟,通过设置自然发展、生态保护优先、经济发展优先、生态-经济均衡4种情景,探讨了如何在兼顾生态环境保护与社会经济发展的情况下进行土地利用的优化配置。结果表明,基于生态-经济均衡情景下的优化方案,土地利用类型的数量结构和空间布局更为合理,其综合效益优于另外3种情景。该情景在合理限制经济发展速度的前提下,使生态建设获得稳定发展,其经济效益较生态保护优先情景下增长了8.96%,生态效益较经济发展优先情景下增长了0.77%,在生态保护与经济发展2种目标之间达到平衡,为西北农牧交错带的土地利用规划提供了决策辅助。  相似文献   

Data Configurations and the Cokriging System: Simplification by Screen Effects   总被引：1，自引：0，他引：1  

A. Subramanyam  H. S. Pandalai 《Mathematical Geosciences》2008,40(4):425-443

Large cokriging systems arise in many situations and are difficult to handle in practice. Simplifications such as simple kriging, strictly collocated and multicollocated cokriging are often used and models under which such simplifications are, in fact, equivalent to cokriging have recently received attention. In this paper, a two-dimensional second-order stationary random process with known mean is considered and the redundancy of certain components of the data at certain locations vis-à-vis the solution to the simple cokriging system is examined. Conditions for the simple cokriging weights of these components at these locations are set to zero. The conditions generalise the notion of the autokrigeability coefficient and can, in principle, be applied to any data configuration. In specific sampling situations such as the isotopic and certain heterotropic configurations, models under which simple kriging, strictly collocated, multicollocated and dislocated cokriging are equivalent to simple cokriging are readily identified and results already available in the literature are obtained. These are readily identified and the results are already available in the literature. The advantage of the approach presented here is that it can be applied to any data configuration for analysis of permissible simplifications in simple cokriging.  相似文献   

Multi-Scale and Multi-Resolution Stochastic Modeling of Subsurface Heterogeneity by Tree-Indexed Markov Chains     

Michel Dekking  Amro Elfeki  Cor Kraaikamp  Johannes Bruining 《Computational Geosciences》2001,5(1):47-60

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Markov chain Monte Carlo methods for conditioning a permeability field to pressure data   总被引：3，自引：0，他引：3  

Dean S. Oliver  Luciane B. Cunha  Albert C. Reynolds 《Mathematical Geology》1997,29(1):61-91

Generating one realization of a random permeability field that is consistent with observed pressure data and a known variogram model is not a difficult problem. If, however, one wants to investigate the uncertainty of reservior behavior, one must generate a large number of realizations and ensure that the distribution of realizations properly reflects the uncertainty in reservoir properties. The most widely used method for conditioning permeability fields to production data has been the method of simulated annealing, in which practitioners attempt to minimize the difference between the ’ ’true and simulated production data, and “true” and simulated variograms. Unfortunately, the meaning of the resulting realization is not clear and the method can be extremely slow. In this paper, we present an alternative approach to generating realizations that are conditional to pressure data, focusing on the distribution of realizations and on the efficiency of the method. Under certain conditions that can be verified easily, the Markov chain Monte Carlo method is known to produce states whose frequencies of appearance correspond to a given probability distribution, so we use this method to generate the realizations. To make the method more efficient, we perturb the states in such a way that the variogram is satisfied automatically and the pressure data are approximately matched at every step. These perturbations make use of sensitivity coefficients calculated from the reservoir simulator.  相似文献   

The GF algorithm for reservoir storage, yield and spillage distributions for non-seasonal and seasonal independent inflow processes     

E. H. Lloyd  D. Warren 《Stochastic Hydrology and Hydraulics》1992,6(2):135-149

a well-known generating function formula for the equilibrium storage distribution in a finite Moran reservoir having IID inflows and unit release is extended to apply to a class of nondecreasing staircase-like release policies withm unit increments,m>1, and to seasonal inflows. The analysis is conducted in terms of an alternative to the Moran inflow-outflow sequencing scheme, with the release during a working interval controlled by the water level at the beginning of that interval.In addition to the storage, the equilibrium distributions of yield and spillage are obtained. Illustrative examples are provided.  相似文献   

Predicting cumulative sediment depostition in large reservoirs     

R. M. Phatarfod  T. E. Unny  K. Ponnambalam 《Stochastic Hydrology and Hydraulics》1990,4(3):241-251

Sediment deposition and its accumulation in a large resorvoir depends on the inflow and reservoir storage content, respectively. Because of this fact it is possible to model the cumulative deposition of sediment as an additive process defined on a bivariate Markov chain. Using the bivariate Markov chain model the mean and variance of the cumulative deposition of John Martin Reservoir, Colorado, U.S.A. are estimated and compared with observed sedimentation data.  相似文献   

Bayesian Equivalent Sample Toolkit (BEST): an Excel VBA program for probabilistic characterisation of geotechnical properties from limited observation data     

Yu Wang  Zijun Cao 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2016,10(4):251-268

In site investigation, the amount of observation data obtained for geotechnical property characterisation is often too sparse to obtain meaningful statistics and probability distributions of geotechnical properties. To address this problem, a Bayesian equivalent sample method was recently developed. This paper aims to generalize the Bayesian equivalent sample method to various geotechnical properties, when measured by different direct or indirect test procedures, and to implement the generalized method in Excel by developing an Excel VBA program called Bayesian Equivalent Sample Toolkit (BEST). The BEST program makes it possible for practitioners to apply the Bayesian equivalent sample method without being compromised by sophisticated algorithms in probability, statistics and simulation. The program is demonstrated and validated through examples of soil and rock property characterisations.  相似文献