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1.
针对传统支持向量机中存在原始数据量过大导致训练速度太慢的问题,同时考虑到非支持向量对支持向量机的训练性能无影响,且影响支持向量机性能的支持向量往往位于边界的特点,提出一种提取边界向量的支持向量机算法.数值实验表明:改进算法在保证支持向量机分类能力的前提下,有效提高了支持向量机的分类效率.  相似文献   

2.
支持向量机学习算法的本质是从训练集中寻找支持向量,因此能否通过训练算法能快速找出支持向量是衡量支持向量机算法优劣的重要标准.本文提出了一种新的快速训练支持向量机的增量学习算法,首先,给出边界向量的定义,然后,对一个给定的新加人的样本,新的学习方法验证其是否为边界向量,如果是,将其加入到训练集中重新训练支持向量机,如果不是,就舍弃,这样能达到减少训练样本、降低训练复杂性目的,最后,给出了一个增量学习算法.实验表明测试误差和支持向量数量与SMO算法大致相当,而训练速度明显加快.  相似文献   

3.
针对光纤陀螺输出信号噪声成分复杂、故障特征难以提取的问题,提出一种基于改进麻雀搜索算法与支持向量机的光纤陀螺故障诊断方法.首先,对光纤陀螺正常信号和故障信号进行3层小波包分解以提取特征向量;其次,通过引入改进Logistic混沌映射和自适应t分布策略,加入边界探索和警戒解除机制,改进麻雀搜索算法并用于支持向量机参数寻优;最后,建立支持向量机模型进行光纤陀螺故障的识别和诊断.经实例分析,提出的方法可有效用于光纤陀螺故障诊断,与麻雀搜索算法、灰狼优化算法、粒子群算法、遗传算法和天牛须算法对比,可有效提高光纤陀螺故障诊断准确率.  相似文献   

4.
基于粗糙集的支持向量回归机混合算法   总被引:1,自引:0,他引:1  
利用粗糙集(RS)对不精确数据的处理能力,生成分类数据的边界集,替代原始样本作为训练集,减少训练集与获取的支持向量的数量,然后使用支持向量机的最小序列优化(SMO)算法改进回归学习机的性能.将粗糙集与SMO回归算法结合提出一种混合函数回归算法RS-SMO-RA.在常用SMO回归算法SMO-RA基础上,扩增一段简短的生成边界样本的算法程序.仿真结果表明,算法RS-SMO-RA的效率更高,且能够改进学习结果的性能.  相似文献   

5.
为了提高潜在支持向量机求解大规模问题的训练速度,提出了基于样本取样的潜在支持向量机序列最小优化算法,去掉了大部分非支持向量,把支持向量逐渐压缩到取样样本集中.此算法特别适合大样本数据且支持向量个数相对较少的情况.实验表明,改进的序列最小优化算法加速了潜在支持向量机分类器训练时间.  相似文献   

6.
提出一种基于两级支持向量机分类的视频镜头分割方法.第1级分类器利用分段视频首尾帧直方图距离,结合滑动窗口和陷波方法计算分段视频的特征向量,通过支持向量机来分类筛选含有镜头边界的子段;第2级分类器根据不同间距的帧间直方图的距离特征,采用时间窗口法构造特征向量,利用二叉树支持向量机多分类策略检测镜头边界的位置.结果表明,所提出的方法能够同时提高切变和渐变的镜头边界的检测效果.  相似文献   

7.
支持向量机的一个边界样本修剪方法   总被引:1,自引:0,他引:1  
支持向量机仅仅由支持向量所决定,而支持向量来自于边界的样本,如果样本集中存在较多的噪音或孤立点,特别是两类样本过分交叉,都会降低支持向量机的推广能力。为了改善支持向量机的推广性能,文章提出一个支持向量机的边界样本修剪方法:首先对边界样本进行抽取,然后用RemoveOnly算法对边界样本进行修剪,修剪后的边界样本就是最终的支持向量机训练样本。实验结果表明,修剪方法可以让支持向量机的推广能力有不同程度的提高。  相似文献   

8.
支持向量机(SVM)花费大量时间用于对非支持向量样本的优化.根据支持向量都是位于两类边界的靠近分类超平面的样本点,本文提出首先利用基于中心距离比值法排除大部分远离分类超平面的样本,然后以最小类间距离样本数作为测度进一步选择边界样本.得到包含所有支持向量的最小样本集,构成新的训练样本集训练SVM.将提出的算法应用于解决医学图像奇异点检测问题.实验结果表明.该算法减小了训练样本集的规模,有效地缩短了SVM训练算法的时间.同时获得了较高的榆出率.  相似文献   

9.
针对大数据环境下并行支持向量机(support vector machine,SVM)算法存在噪声数据较敏感、训练样本数据冗余等问题,提出基于粒度和信息熵的GIESVM-MR(the SVM algorithm by using granularity and information entropy based on MapReduce)算法.该算法首先提出噪声清除策略(noise cleaning,NC)对每个特征属性的重要程度进行评价,获得样本与类别之间的相关度,以达到识别和删除噪声数据的目的;其次提出基于粒度的数据压缩策略(data compression based on granulation,GDC),通过筛选信息粒的方式保留类边界样本删除非支持向量,得到规模较小的数据集,从而解决了大数据环境下训练样本数据冗余问题;最后结合Bagging的思想和MapReduce计算模型并行化训练SVM,生成最终的分类模型.实验表明,GIESVM-MR算法的分类效果更佳,且在大规模的数据集下算法的执行效率更高.  相似文献   

10.
针对不平衡数据集数据分布不均匀及边界模糊的特点,提出基于局部密度改进的SVM不平衡数据集分类算法.该算法先将多数类划分成多个子类,并依据子类内每个样本的局部密度选出边界区域、靠近边界区域的与少数类数目相等的样本,与少数类完成SVM初始分类;用所得的支持向量机和剩余的多数类样本对初始分类器进行迭代优化.结果表明,与WSVM,ALSMOTE-SVM和基本SVM算法相比,该算法分类效果良好,能有效改进SVM算法在分布不均匀及边界模糊数据集上的分类性能.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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-  相似文献   

18.
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-  相似文献   

19.
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  相似文献   

20.
<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  相似文献   

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