WWW上用户的访问路径信息会被记录在WEB服务器的日志记录中,分析这些日志并挖掘出用户的主要行为模式,可以提取出WEB网站被频繁访问的主干部分。本文首先将原始日志信息整理成目标页前向访问路径集TUPD(Target Pages User Forward Acces...WWW上用户的访问路径信息会被记录在WEB服务器的日志记录中,分析这些日志并挖掘出用户的主要行为模式,可以提取出WEB网站被频繁访问的主干部分。本文首先将原始日志信息整理成目标页前向访问路径集TUPD(Target Pages User Forward Access Path Dataset),然后在TUPD上生成加权网站结构多维树WWSSMT(Weighted Web Site Structure Multi-Tree),最后引入决策频度阀值S,删除所有WWSSMT中weight<S的子结点分支,最终实现了此WEB站点的频繁访问主干子网的发现。实验证明,挖掘获得的主干子网包含了某电子商务网站的最主要热销产品。展开更多
Economic shale gas production requires hydraulic fracture stimulation to increase the formation permeability. Hydraulic fracturing strongly depends on geomechanical parameters such as Young＇s modulus and Poisson＇s r...Economic shale gas production requires hydraulic fracture stimulation to increase the formation permeability. Hydraulic fracturing strongly depends on geomechanical parameters such as Young＇s modulus and Poisson＇s ratio. Fracture-prone sweet spots can be predicted by prestack inversion, which is an ill-posed problem; thus, regularization is needed to obtain unique and stable solutions. To characterize gas-bearing shale sedimentary bodies, elastic parameter variations are regarded as an anisotropic Markov random field. Bayesian statistics are adopted for transforming prestack inversion to the maximum posterior probability. Two energy functions for the lateral and vertical directions are used to describe the distribution, and the expectation-maximization algorithm is used to estimate the hyperparameters of the prior probability of elastic parameters. Finally, the inversion yields clear geological boundaries, high vertical resolution, and reasonable lateral continuity using the conjugate gradient method to minimize the objective function. Antinoise and imaging ability of the method were tested using synthetic and real data.展开更多
文摘WWW上用户的访问路径信息会被记录在WEB服务器的日志记录中,分析这些日志并挖掘出用户的主要行为模式,可以提取出WEB网站被频繁访问的主干部分。本文首先将原始日志信息整理成目标页前向访问路径集TUPD(Target Pages User Forward Access Path Dataset),然后在TUPD上生成加权网站结构多维树WWSSMT(Weighted Web Site Structure Multi-Tree),最后引入决策频度阀值S,删除所有WWSSMT中weight<S的子结点分支,最终实现了此WEB站点的频繁访问主干子网的发现。实验证明,挖掘获得的主干子网包含了某电子商务网站的最主要热销产品。
基金supported by CNPC fundamental research project(No.2014E-3204)
文摘Economic shale gas production requires hydraulic fracture stimulation to increase the formation permeability. Hydraulic fracturing strongly depends on geomechanical parameters such as Young＇s modulus and Poisson＇s ratio. Fracture-prone sweet spots can be predicted by prestack inversion, which is an ill-posed problem; thus, regularization is needed to obtain unique and stable solutions. To characterize gas-bearing shale sedimentary bodies, elastic parameter variations are regarded as an anisotropic Markov random field. Bayesian statistics are adopted for transforming prestack inversion to the maximum posterior probability. Two energy functions for the lateral and vertical directions are used to describe the distribution, and the expectation-maximization algorithm is used to estimate the hyperparameters of the prior probability of elastic parameters. Finally, the inversion yields clear geological boundaries, high vertical resolution, and reasonable lateral continuity using the conjugate gradient method to minimize the objective function. Antinoise and imaging ability of the method were tested using synthetic and real data.
