数据挖掘中改进的C4.5决策树分类算法

针对传统C4.5决策树分类算法需要进行多次扫描,导致运行效率低的缺陷,提出一种新的改进C4.5决策树分类算法.通过优化信息增益推导算法中相关的对数运算,以减少决策树分类算法的运行时间;将传统算法中连续属性的简单分裂属性改进为最优划分点分裂处理,以提高算法效率.实验结果表明,改进的C4.5决策树分类算法相比传统的C4.5决策树分类算法极大提高了执行效率,减小了需求空间.     

一种基于Rough sets生成决策树的算法改进

介绍了决策树算法的含义和构筑方法，对基于加权平均粗糙度构造决策树算法进行改进，通过实例说明了改进算法的优势。     

基于粗糙集决策树优化研究

决策树分类方法是一种有效的数据挖掘分类方法.单变量决策树结构简单,但规模较大.多变量决策树是为了进一步缩减树的规模而提出的决策树结构,通过选取属性的合理组合作为分裂属性,可使树的规模相对较小.文章在对以往所提出的混合变量决策树算法RSH2的抗噪性差和属性被多次选取等问题进行改进的基础上,提出了基于粗糙集的多变量决策树算法VPMDT.通过与ID3、HACRs、RSH2和C4.5等算法进行的实验比较表明,VPMDT有较好的时空性能,并保持较高的分类预测正确率.     

决策树方法使用中的改进策略

本文介绍了决策树方法的基本理论，详细介绍了决策树的经典算法ID3算法的使用条件，提出了在实际应用中的限制，并对该算法实际的应用提出了改进措施，使决策树方法能更好的为数据挖掘领域服务。     

C4.5算法在民航CBT中的应用

决策树学习策略广泛应用于模式识别和机器学习等领域,用来解决与分类相关的问题。决策树剪枝的作用是简化决策树,提高决策树的泛化能力,避免对训练集的过适应,是决策树学习中的重要研究内容。本文详细介绍了数据挖掘算法中的C4.5算法的基本思想,并且对REP剪枝技术进行分析,以此对C4.5算法进行剪枝。实验表明改进的C4.5算法与原C4.5算法相比能很好地处理训练集的非平衡性,并降低决策树的规模,效率得到提高。     

决策树算法的研究与改进

决策树是数据挖掘中重要的分类方法，本文在研究和比较几种经典的决策树算法基础上，提出了一种改进的决策树算法：基于度量的决策树（MBDT）．这种决策树实际上是把线性分类器和决策树结合在一起．实验证明，用该方法构造的决策树能有效地减少决策树的层数，从而提高决策树的分类效率．通过MBDT分类实验，验证了上面结论的正确性和有效性．     

一种新的简化ID3决策树的算法

决策树简化是决策树学习算法中的一个重要分支。文章以 ID3算法构造的决策树为基础 ,提出了一种高效的简化决策树的算法。算法先序遍历由 ID3构造出来的决策树的各个节点并对其子树进行比较 ,如果各子树的属性都相同而且存在某些相应的分支对于各子树完全相同 ,则改变决策树中相应属性的层次关系并把相同的分支分别合并起来。算法减少了决策树的深度、宽度与叶子数目 ,降低了决策树的规模。尤其对于逻辑表达式的归纳学习 ,简化之后的决策树要明显优于原决策树。     

基于决策属性挑选策略的改进的决策树算法

首先介绍了决策树算法的基本理论和建模过程及传统的决策属性的选取标准。然后介绍了传统的ID3决策树算法,并对常用决策树算法的优缺点进行了总结。以经典的决策树ID3模型为基础,对已有决策属性挑选策略进行了分析和总结,对决策属性挑选策略进行了改进,提出了基于"相关信息增益度"的决策属性挑选策略。该方法基于信息增益的计算标准,并通过引入属性间相关性关系对传统ID3算法"多值偏向性"的缺陷进行补偿。最后,将该方法应用于UCI数据中心的标准数据集合中,从分类精确度方面对改进的ID3算法和传统ID3算法进行比较和分析。通过实验分析,改进的E-ID3算法在分类精确度方面有更优秀的性能表现。     

一种改进ID3型决策树挖掘算法

分析经典ID3型决策树挖掘算法中存在的问题,对其熵值计算过程进行改进,构建一种改进的ID3型决策树挖掘算法.重新设计决策树构建中的熵值计算过程,以获得具有全局最优的挖掘结果,并针对UCI数据集中的6类数据集展开挖掘实验.结果表明:改进后的挖掘算法在决策树构建的简洁程度和挖掘精度上,都明显优于ID3型决策树挖掘算法.     

改进决策树算法在企业资源计划系统中的应用

为改进企业资源计划(ERP)的数据挖掘技术和提高利用效率,改善ERP系统的预测功能和决策支持,通过运用改进的混合决策树算法ID3,对企业ERP系统中某些决策判定的依据进行学习,根据学习结果对ERP系统中的新问题进行预测. 给出了相关的算法流程和实现步骤. 实验结果验证了改进决策树算法在决策预测支持中的有效性和可行性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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