电子印章在我国电子政务和电子商务领域正发挥着越来越重要的作用,基于数字签名和数字水印的电子印章解决方案还在发展完善中。该文遵循Domino—PDF—DSA这一技术路线,综合运用Lotus平台的PKI技术和PDF的数字签名技术,借助Notes C API和...电子印章在我国电子政务和电子商务领域正发挥着越来越重要的作用,基于数字签名和数字水印的电子印章解决方案还在发展完善中。该文遵循Domino—PDF—DSA这一技术路线,综合运用Lotus平台的PKI技术和PDF的数字签名技术,借助Notes C API和PDF API作二次开发,将电子印章图像作为Notes ID文件的扩展部分,在Lotus平台上实现了对PDF文档加盖电子印章的应用系统。展开更多
The motivation of this study is to investigate the turbulence-chemistry interactions by using probability density function （PDF） method. A consistent hybrid Reynolds Averaged Navier-Stokes （RANS）/PDF method is use...The motivation of this study is to investigate the turbulence-chemistry interactions by using probability density function （PDF） method. A consistent hybrid Reynolds Averaged Navier-Stokes （RANS）/PDF method is used to simulate the turbulent non-reacting and reacting flows. The joint fluctuating velocity-frequency-composition PDF equation coupled with the Reynolds averaged density, momentum and energy equations are solved on unstructured meshes by the Lagrangian Monte Carlo （MC） method combined with the finite volume （FV） method. The simulation of the axisymmetric bluff body stabilized non-reacting flow fields is presented in this paper. The calculated length of the recirculation zone is in good agreement with the experimental data. Moreover, the significant change of the flow pattern with the increase of the jet-to-coflow momentum flux ratio is well predicted. In addition, comparisons are made between the joint PDF model and two different Reynolds stress models.展开更多
In this letter,by employing Gaussian distribution to approximate the probability density function(pdf) of the extrinsic information at the output of the multiuser detector as a function of the pdf of the input extrins...In this letter,by employing Gaussian distribution to approximate the probability density function(pdf) of the extrinsic information at the output of the multiuser detector as a function of the pdf of the input extrinsic messages,it is concluded that the Probabilistic Data Association(PDA) algorithm is equivalent to the Soft Interference Cancellation plus Minimum Mean Square Error algo-rithm(SIC-MMSE) .展开更多
该文提出一种多文档关键词抽取方法,该方法提出ATF×PDF(Average Term Frequency×ProportionalDocument Frequency)来计算词语权重,并根据候选关键词之间的语义相似度,采用联合权重方法重新计算候选关键词的权重来抽取关键词...该文提出一种多文档关键词抽取方法,该方法提出ATF×PDF(Average Term Frequency×ProportionalDocument Frequency)来计算词语权重,并根据候选关键词之间的语义相似度,采用联合权重方法重新计算候选关键词的权重来抽取关键词。该方法综合考虑了词语的频率,词性以及词语之间的语义相似性等信息,实验表明,该方法能有效抽取多个文档的关键词,同基于关键词的聚类标记方法相比,其准确率提高3%,召回率提高7%,F-measure提高4.4%。展开更多
文摘电子印章在我国电子政务和电子商务领域正发挥着越来越重要的作用,基于数字签名和数字水印的电子印章解决方案还在发展完善中。该文遵循Domino—PDF—DSA这一技术路线,综合运用Lotus平台的PKI技术和PDF的数字签名技术,借助Notes C API和PDF API作二次开发,将电子印章图像作为Notes ID文件的扩展部分,在Lotus平台上实现了对PDF文档加盖电子印章的应用系统。
基金The project supported by the National Natural Science Foundation of China (50506028)Action Scheme for Invigorating Education Towards the twenty-first century
文摘The motivation of this study is to investigate the turbulence-chemistry interactions by using probability density function （PDF） method. A consistent hybrid Reynolds Averaged Navier-Stokes （RANS）/PDF method is used to simulate the turbulent non-reacting and reacting flows. The joint fluctuating velocity-frequency-composition PDF equation coupled with the Reynolds averaged density, momentum and energy equations are solved on unstructured meshes by the Lagrangian Monte Carlo （MC） method combined with the finite volume （FV） method. The simulation of the axisymmetric bluff body stabilized non-reacting flow fields is presented in this paper. The calculated length of the recirculation zone is in good agreement with the experimental data. Moreover, the significant change of the flow pattern with the increase of the jet-to-coflow momentum flux ratio is well predicted. In addition, comparisons are made between the joint PDF model and two different Reynolds stress models.
文摘In this letter,by employing Gaussian distribution to approximate the probability density function(pdf) of the extrinsic information at the output of the multiuser detector as a function of the pdf of the input extrinsic messages,it is concluded that the Probabilistic Data Association(PDA) algorithm is equivalent to the Soft Interference Cancellation plus Minimum Mean Square Error algo-rithm(SIC-MMSE) .
文摘该文提出一种多文档关键词抽取方法,该方法提出ATF×PDF(Average Term Frequency×ProportionalDocument Frequency)来计算词语权重,并根据候选关键词之间的语义相似度,采用联合权重方法重新计算候选关键词的权重来抽取关键词。该方法综合考虑了词语的频率,词性以及词语之间的语义相似性等信息,实验表明,该方法能有效抽取多个文档的关键词,同基于关键词的聚类标记方法相比,其准确率提高3%,召回率提高7%,F-measure提高4.4%。
