基于半监督K-means的K值全局寻优算法

提出一种基于半监督K-means的K值全局寻优算法,该算法打破传统方法中采用样本类别作为K值的限定,利用少量标记数据即可指导和规划大量无监督数据.结合数据集自身的分布特点及聚类后各个簇内的监督信息,根据投票方法来指导簇中数据集的类别标记.实验表明,本文所提出的方法可以有效的寻找适合数据集的最佳K值和聚类的中心,提高聚类性能.     

基于半监督学习的中文多文档子主题划分

为了能在多文档自动摘要过程中更好地划分子主题,提出了一种基于半监督学习的子主题划分方法:首先计算句子的语义相似度;然后通过层次聚类对可信度高的句子进行主题类别标记,生成少量已标记主题类别的句子集,在此基础上对所有句子进行constrained-k-means聚类,通过交叉验证的方法确定子主题的数目k;最后使用k-means聚类获得多文档的各个子主题.实验结果表明,该方法有效地提高了子主题的识别率.     

k-means聚类算法的MapReduce并行化实现

针对k-means聚类算法特点,给出了MapReduce编程模型实现k-means聚类算法的方法,Map函数完成每个记录到聚类中心距离的计算并重新标记其属于的新聚类类别,Reduce函数根据Map函数得到的中间结果计算出新的聚类中心,供下一轮MapReduce Job使用.实验结果表明:k-means算法MapReduce并行化后部署在Hadoop集群上运行,具有较好的加速比和良好的扩展性.     

基于云计算的并行k-means算法研究

针对传统k-means聚类算法面对海量数据存在时间复杂度急剧增加的问题,结合云计算的优势,提出基于MapReduce编程框架来实现k-means聚类算法的并行化处理。Map函数完成每个样本记录到聚类中心的距离计算并标记其所属聚类类别,Reduce函数汇总中间结果并计算出新的聚类中心,供下一轮迭代使用。通过实验表明:基于MapReduce的并行化k-means聚类算法具有较好的加速比和良好的扩展性。     

一种基于Seeds集和成对约束的主动半监督聚类算法

针对半监督聚类算法中监督信息使用不充分,监督信息中信息含有量低的问题,提出一种结合主动学习的半监督聚类算法.首先结合使用数据的类别标记和成对约束信息,指导Kmeans聚类过程,设计出一种基于Seeds集和成对约束的半监督聚类算法SC-Kmeans;其次将主动学习算法引入到SC-Kmeans中,以尽量小的代价选取信息含有量更高的监督信息,提高SC-Kmeans算法的聚类精度;最后在UCI标准数据集上进行仿真实验.实验结果表明,该算法取得了较好的聚类效果,有效提高了聚类准确率.     

半监督模糊聚类及其应用

提出了一种拓展的半监督模糊聚类模型,给出求解这个模型的迭代公式.这种半监督聚类能够合理、有效地利用部分已标识样本的类别信息对未标识样本产生影响,从而提高半聚类算法的聚类效果.其隶属度和聚类中心的迭代公式具有和FCM算法一样简洁的表示.在黄瓜数据集上的聚类分析表明,新提出的半监督聚类优于未改进的两种半监督算法、FCM算法和线性判别方法.     

半监督平面聚类算法设计

采用以平面为原型来拟合样本的思想设计学习机,已在机器学习和数据挖掘等领域引起广泛关注,然而,如何利用少量标记样本,兼顾平面原型特点实现聚类,鲜见报道.以kPC(k-Plane Clustering)为切入点,在有标样本极端少的情况下,设计了半监督型平面聚类算法semi-kPC.考虑到L1范数较L2范数更为鲁棒的事实,在已有工作L1kPC(L1 norm kPC)的基础上,提出基于L1范数的半监督聚类方法 semi-L1kPC.从每类仅有一个已标样本出发,在人工数据集和UCI数据集上的实验表明:(1)在XOR(Exclusive OR)问题上,平面型的聚类方法的聚类准确率均显著高于k-means算法,因为k-means无法利用平面特性;(2)在引入少量监督信息后,半监督型聚类方法 semi-kPC和semi-L1kPC比其他聚类方法的聚类准确率更高;(3)采用L1范数的semi-L1kPC比semi-kPC的鲁棒性更好.     

一种基于半监督的大规模数据集聚类算法

待挖掘数据集规模的不断增长,以往的聚类算法由于需要多次扫描原始数据集而不再适用,现阶段,一遍扫描原始数据集即完成聚类的算法成为了首要的研究目标.但是,现有针对大规模数据集的算法容易受到初始化参数以及原始数据集分布的影响,聚类结果质量不高,并且也不稳定.对此,吸收半监督聚类的思想,提出了基于标记集的半监督一遍扫描K均值算法,该算法利用驻留主存的标记集指导聚类过程,使得聚类效率以及聚类结果的质量得到了进一步的提高.在人工生成数据集以及1998KDD数据集上验证了该算法的有效性.     

一种最大化样本可分性半监督Boosting算法

针对数据实际分布与假设不匹配时半监督学习算法难以改善分类器性能的问题,该文提出一种最大化样本可分性半监督Boosting算法,通过引入"高密度区域局部散度最小、样本空间全局散度最大"准则来学习未标注的样本。该准则使用两种半监督假设(聚类假设和流形假设),减少了因半监督假设与数据不匹配造成的准确率下降问题。实验结果表明,该文算法有效提高了Boosting算法在符合聚类假设数据集和符合流形假设数据集上的准确性,提高了分类器噪声数据的稳定性。     

一种基于密度的无监督聚类算法

分析了k-means算法的缺陷、入侵检测特点和网络中数据的特点,提出了一种基于密度的无监督2次聚类算法—KD算法。该算法聚类使用改进的k-means算法并引入基于密度聚类算法的优点,以提高对单种入侵数据集及混合入侵数据集的检测效果。实验结果表明,该算法具有较高的检测率和较低的误检率。     

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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