中文领域术语抽取是中文信息处理领域的一项重要研究任务,在词典构建、领域本体构造等方面有重要的应用.采用条件随机场(conditional random fields,CRFs),从汽车知识网站上爬取网页,预处理后得到纯文本,然后分析汽车领域的术语组成特...中文领域术语抽取是中文信息处理领域的一项重要研究任务,在词典构建、领域本体构造等方面有重要的应用.采用条件随机场(conditional random fields,CRFs),从汽车知识网站上爬取网页,预处理后得到纯文本,然后分析汽车领域的术语组成特点并制定相应的语料标注规则进行人工标注,对汽车领域进行了术语抽取.在使用词和词性特征的基础上增加了词典特征、领域词频和背景领域词频等特征,精确率、召回率和F-值分别达到84.61%、80.50%和82.50%.与其他方法比较说明所提出的汽车领域术语抽取方法是有效的.展开更多
传统的高斯混合模型(Gaussian mixture model,GMM)算法在图像分割中未考虑像素的空间信息,导致其对于噪声十分敏感.马尔科夫随机场(Markov random field,MRF)模型通过像素类别标记的Gibbs分布先验概率引入了图像的空间信息,能较好地分...传统的高斯混合模型(Gaussian mixture model,GMM)算法在图像分割中未考虑像素的空间信息,导致其对于噪声十分敏感.马尔科夫随机场(Markov random field,MRF)模型通过像素类别标记的Gibbs分布先验概率引入了图像的空间信息,能较好地分割含有噪声的图像,然而MRF模型的分割结果容易出现过平滑现象.为了解决上述缺陷,提出了一种新的基于图像片权重方法的马尔科夫随机场图像分割模型,对邻域内的不同图像片根据相似度赋予不同的权重,使其在克服噪声影响的同时能保持图像细节信息.同时,采用KL距离引入先验概率与后验概率关于熵的惩罚项,并对该惩罚项进行平滑,得到最终的分割结果.实验结果表明,算法具有较强的自适应性,能够有效克服噪声对于分割结果的影响,并获得较高的分割精度.展开更多
A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations betwe...A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations between words, and case types to train the models of CRF ＋ ＋ and de- pendency parser. On the basis of the data set in Beijing Forest Studio-Chinese Tagged Corpus （ BFS- CTC）, the proposed method obtains precision value of 73.63% in open test. This result shows that the formalized computer processing can construct the sentential semantic structure absolutely. The features of predicates, topic and comment extracted with the method can be applied in Chinese in- formation processing directly for promoting the development of Chinese semantic analysis. The method makes the analysis of sentential semantic analysis based on large scale of data possible. It is a tool for expanding the corpus and has certain theoretical research and practical application value.展开更多
Substitutional charge disorder as in PbMg_(1/3)Nb_(2/3)O_(3),structural cation vacancies as in Sr_(x)Ba_(1-x)Nb_(2)O_(6) and isovalent substitution of off-centered cations as in BaTi_(1-x)Sn^(x)O_(3) and BaTi1-xZrxO_(...Substitutional charge disorder as in PbMg_(1/3)Nb_(2/3)O_(3),structural cation vacancies as in Sr_(x)Ba_(1-x)Nb_(2)O_(6) and isovalent substitution of off-centered cations as in BaTi_(1-x)Sn^(x)O_(3) and BaTi1-xZrxO_(3) give rise to quenched electric random-fields(RFs),which we proposed to be at the origin of the peculiar behavior of relaxor ferroelectrics 20 years ago.These are,e.g.a strong frequency dispersion of the dielectric response and an apparent lack of macroscopic symmetry breaking in the low temperature phase.Both are related to mesoscopic RF-driven phase transitions,which give rise to irregularly shaped quasi-stable polar nanoregions below the characteristic temperature T^(*),but above the global transition temperature Tc.Their co-existence with the paraelectric parent phase can be modeled by time-dependentfield equations under the control of quenched RFs and stress-free strain(in the case of order parameter dimension n2).Transitions into global polar order at Tc may occur in uniaxial relaxors as observed on the uniaxial relaxor ferroelectric Sr0.8Ba_(0.2)Nb_(2)O_(6) and come close to RF Ising model criticality.Re-entrant relaxor transitions as observed in solid solutions of Ba_(2)Pr_(0.6)Nd_(0.4)(FeNb_(4))O_(15) are proposed to evidence the coexistence of distinct normal and relaxor ferroelectric phases within the framework of percolation theory.Keywords.展开更多
文摘中文领域术语抽取是中文信息处理领域的一项重要研究任务,在词典构建、领域本体构造等方面有重要的应用.采用条件随机场(conditional random fields,CRFs),从汽车知识网站上爬取网页,预处理后得到纯文本,然后分析汽车领域的术语组成特点并制定相应的语料标注规则进行人工标注,对汽车领域进行了术语抽取.在使用词和词性特征的基础上增加了词典特征、领域词频和背景领域词频等特征,精确率、召回率和F-值分别达到84.61%、80.50%和82.50%.与其他方法比较说明所提出的汽车领域术语抽取方法是有效的.
文摘传统的高斯混合模型(Gaussian mixture model,GMM)算法在图像分割中未考虑像素的空间信息,导致其对于噪声十分敏感.马尔科夫随机场(Markov random field,MRF)模型通过像素类别标记的Gibbs分布先验概率引入了图像的空间信息,能较好地分割含有噪声的图像,然而MRF模型的分割结果容易出现过平滑现象.为了解决上述缺陷,提出了一种新的基于图像片权重方法的马尔科夫随机场图像分割模型,对邻域内的不同图像片根据相似度赋予不同的权重,使其在克服噪声影响的同时能保持图像细节信息.同时,采用KL距离引入先验概率与后验概率关于熵的惩罚项,并对该惩罚项进行平滑,得到最终的分割结果.实验结果表明,算法具有较强的自适应性,能够有效克服噪声对于分割结果的影响,并获得较高的分割精度.
基金Supported by the Science and Technology Innovation Plan of Beijing Institute of Technology(2013)
文摘A new method is proposed for constructing the Chinese sentential semantic structure in this paper. The method adopts the features including predicates, relations between predicates and basic arguments, relations between words, and case types to train the models of CRF ＋ ＋ and de- pendency parser. On the basis of the data set in Beijing Forest Studio-Chinese Tagged Corpus （ BFS- CTC）, the proposed method obtains precision value of 73.63% in open test. This result shows that the formalized computer processing can construct the sentential semantic structure absolutely. The features of predicates, topic and comment extracted with the method can be applied in Chinese in- formation processing directly for promoting the development of Chinese semantic analysis. The method makes the analysis of sentential semantic analysis based on large scale of data possible. It is a tool for expanding the corpus and has certain theoretical research and practical application value.
文摘Substitutional charge disorder as in PbMg_(1/3)Nb_(2/3)O_(3),structural cation vacancies as in Sr_(x)Ba_(1-x)Nb_(2)O_(6) and isovalent substitution of off-centered cations as in BaTi_(1-x)Sn^(x)O_(3) and BaTi1-xZrxO_(3) give rise to quenched electric random-fields(RFs),which we proposed to be at the origin of the peculiar behavior of relaxor ferroelectrics 20 years ago.These are,e.g.a strong frequency dispersion of the dielectric response and an apparent lack of macroscopic symmetry breaking in the low temperature phase.Both are related to mesoscopic RF-driven phase transitions,which give rise to irregularly shaped quasi-stable polar nanoregions below the characteristic temperature T^(*),but above the global transition temperature Tc.Their co-existence with the paraelectric parent phase can be modeled by time-dependentfield equations under the control of quenched RFs and stress-free strain(in the case of order parameter dimension n2).Transitions into global polar order at Tc may occur in uniaxial relaxors as observed on the uniaxial relaxor ferroelectric Sr0.8Ba_(0.2)Nb_(2)O_(6) and come close to RF Ising model criticality.Re-entrant relaxor transitions as observed in solid solutions of Ba_(2)Pr_(0.6)Nd_(0.4)(FeNb_(4))O_(15) are proposed to evidence the coexistence of distinct normal and relaxor ferroelectric phases within the framework of percolation theory.Keywords.
