An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimi...An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimilarity between a pair of mapping sequences.This method selects self-mapping which exists between data by exhaustive search based on relation and attribute information.Experimental results confirm that the improved method constructs comprehensive and accurate decision tree.Moreover,an example shows that the self-mapping decision tree is promising for data mining and knowledge discovery.展开更多
We prove that over an algebraically closed field of arbitrary characteristic,a bounded-degree group of birational self-maps of an irreducible projective variety can be simultaneously regularized.In other words,there e...We prove that over an algebraically closed field of arbitrary characteristic,a bounded-degree group of birational self-maps of an irreducible projective variety can be simultaneously regularized.In other words,there exists another projective variety that is birational to the original one such that every element of the boundeddegree group turns into an automorphism after the birational transformation.Over the field of complex numbers,this result was stated in an article by Cantat(2014)and the proof originates from a work of Huckleberry and Zaitsev(1996).The original proof,however,is not purely algebraic.By adapting their methods,we provide a purely algebraic proof of this statement in arbitrary characteristic.Moreover,we discuss a corollary of this result that is useful in arithmetic dynamics.展开更多
南水入冀新水情下,百泉泉域地下水环境发生改变,岩溶地下水地球化学过程有待查明。综合利用数值模拟、机器学习(自组织聚类)和同位素(δD和δ^(18)O)等方法系统揭示了矿业活动与南水入冀下百泉泉域岩溶地下水地球化学过程,并基于熵变权...南水入冀新水情下,百泉泉域地下水环境发生改变,岩溶地下水地球化学过程有待查明。综合利用数值模拟、机器学习(自组织聚类)和同位素(δD和δ^(18)O)等方法系统揭示了矿业活动与南水入冀下百泉泉域岩溶地下水地球化学过程,并基于熵变权水质指数(Entropy-weighted water quality index,EWQI)进行了水质分级评价。南水入冀后,百泉泉域岩溶地下水位整体抬升。时间上,呈现出既有年际动态变化又有年内季节变化特征。空间上,补给区表现为剧变型,而径流、排泄区呈缓变型。地下水降落漏斗主要分布在泉域东南部的煤、铁矿密集区。泉域岩溶地下水呈弱碱性,水化学类型以Ca-HCO_(3)型和Ca-SO_(4)型为主导。主要阴阳离子质量浓度遵循ρ(HCO_(3)^(-))>ρ(SO_(4)^(2-))>ρ(Cl^(-))和ρ(Ca^(2+))>ρ(Mg^(2+))>ρ(Na^(+))>ρ(K^(+))的顺序。各离子沿着径流路径呈现出逐渐增大的空间分布特征。岩溶地下水化学成分主要受岩石(方解石、白云石和石膏)风化溶解和反向阳离子交换作用主导。人为活动对泉域岩溶地下水系统中的SO_(4)^(2-)和NO_(3)^(-)质量浓度有一定程度影响。岩溶地下水来源于大气降水,并且在入渗前发生了二次蒸发作用,氘盈余值在径流过程中有所降低。水质评价结果表明,岩溶地下水质量整体优于第四系地下水,分别有50%的岩溶水和37.5%的第四系水样满足饮用目的。TDS、ρ(SO_(4)^(2-))和ρ(NO_(3)^(-))是影响泉域地下水水质的关键指标。引起泉域岩溶地下水系统水质恶化的潜在人类活动主要包括矿山排水、农业灌溉和城市污水排放。通过水质分级评价,提出了泉域地下水环境保护措施。研究结果将有助于为百泉泉域岩溶地下水资源的供水安全和地下水环境保护治理提供参考。展开更多
Let I = [0,1], 0 < a < b < 1. Let Φab ≡ {F ∈ C0(I): both F|[0,a] and F|[b, 1] are strictly increasing, and F|[a, b] is constant }. In this paper we discuss necessary and sufficient conditions for F ∈Φab ...Let I = [0,1], 0 < a < b < 1. Let Φab ≡ {F ∈ C0(I): both F|[0,a] and F|[b, 1] are strictly increasing, and F|[a, b] is constant }. In this paper we discuss necessary and sufficient conditions for F ∈Φab to have monotone iterative roots.展开更多
文摘An improved decision tree method for web information retrieval with self-mapping attributes is proposed.The self-mapping tree has a value of self-mapping attribute in its internal node,and information based on dissimilarity between a pair of mapping sequences.This method selects self-mapping which exists between data by exhaustive search based on relation and attribute information.Experimental results confirm that the improved method constructs comprehensive and accurate decision tree.Moreover,an example shows that the self-mapping decision tree is promising for data mining and knowledge discovery.
基金supported by National Natural Science Foundation of China(Grant No.12271007)。
文摘We prove that over an algebraically closed field of arbitrary characteristic,a bounded-degree group of birational self-maps of an irreducible projective variety can be simultaneously regularized.In other words,there exists another projective variety that is birational to the original one such that every element of the boundeddegree group turns into an automorphism after the birational transformation.Over the field of complex numbers,this result was stated in an article by Cantat(2014)and the proof originates from a work of Huckleberry and Zaitsev(1996).The original proof,however,is not purely algebraic.By adapting their methods,we provide a purely algebraic proof of this statement in arbitrary characteristic.Moreover,we discuss a corollary of this result that is useful in arithmetic dynamics.
文摘南水入冀新水情下,百泉泉域地下水环境发生改变,岩溶地下水地球化学过程有待查明。综合利用数值模拟、机器学习(自组织聚类)和同位素(δD和δ^(18)O)等方法系统揭示了矿业活动与南水入冀下百泉泉域岩溶地下水地球化学过程,并基于熵变权水质指数(Entropy-weighted water quality index,EWQI)进行了水质分级评价。南水入冀后,百泉泉域岩溶地下水位整体抬升。时间上,呈现出既有年际动态变化又有年内季节变化特征。空间上,补给区表现为剧变型,而径流、排泄区呈缓变型。地下水降落漏斗主要分布在泉域东南部的煤、铁矿密集区。泉域岩溶地下水呈弱碱性,水化学类型以Ca-HCO_(3)型和Ca-SO_(4)型为主导。主要阴阳离子质量浓度遵循ρ(HCO_(3)^(-))>ρ(SO_(4)^(2-))>ρ(Cl^(-))和ρ(Ca^(2+))>ρ(Mg^(2+))>ρ(Na^(+))>ρ(K^(+))的顺序。各离子沿着径流路径呈现出逐渐增大的空间分布特征。岩溶地下水化学成分主要受岩石(方解石、白云石和石膏)风化溶解和反向阳离子交换作用主导。人为活动对泉域岩溶地下水系统中的SO_(4)^(2-)和NO_(3)^(-)质量浓度有一定程度影响。岩溶地下水来源于大气降水,并且在入渗前发生了二次蒸发作用,氘盈余值在径流过程中有所降低。水质评价结果表明,岩溶地下水质量整体优于第四系地下水,分别有50%的岩溶水和37.5%的第四系水样满足饮用目的。TDS、ρ(SO_(4)^(2-))和ρ(NO_(3)^(-))是影响泉域地下水水质的关键指标。引起泉域岩溶地下水系统水质恶化的潜在人类活动主要包括矿山排水、农业灌溉和城市污水排放。通过水质分级评价,提出了泉域地下水环境保护措施。研究结果将有助于为百泉泉域岩溶地下水资源的供水安全和地下水环境保护治理提供参考。
文摘在自组织映射(Self-organizing Map,SOM)模型的训练过程中,不同类数据对权重矩阵的更新有不同作用,某一类数据对权重矩阵的更新会对其他类获胜神经元特征向量产生偏离其数据特征的影响,从而降低算法聚类精度。针对以上问题,提出一种改进的基于置信度SOM模型(Improved Confidence-based SOM Model,icSOM)。样本数据首先由K-means算法初步分类,为模型训练提供更多的数据信息;然后将预分类后的数据分别训练相互独立的SOM模型,以消除不同类之间的影响;最后在传统SOM模型基础上提出置信度矩阵概念,通过综合判断获胜神经元的置信度及其与输入数据间的欧氏距离最终得到置信神经元,根据置信神经元所属类别给数据分配聚类标签。在鸢尾花数据集(Iris)及葡萄酒数据集(Wine)上利用icSOM进行聚类分析,实验结果表明,所提算法可以更好地处理样本数据,取得了较好的聚类效果。
基金Supported by the National Natural Science Foundation of China !(19961001)
文摘Let I = [0,1], 0 < a < b < 1. Let Φab ≡ {F ∈ C0(I): both F|[0,a] and F|[b, 1] are strictly increasing, and F|[a, b] is constant }. In this paper we discuss necessary and sufficient conditions for F ∈Φab to have monotone iterative roots.
