基于改进集成学习分类的代理辅助进化算法

当使用代理辅助进化算法求解昂贵高维多目标优化问题时,代理模型通常用于近似昂贵的适应度函数.然而,随着目标数的增加,近似误差将逐渐累积,计算量也会急剧增加.对此,提出一种基于改进集成学习分类的代理辅助进化算法,使用一种改进的装袋集成学习分类器作为代理模型.首先,从被昂贵的适应度评价的个体中选择一组分类边界,将所有个体分成两类;其次,利用这些带有分类标签的个体训练分类器,以对候选个体的类别进行预测;最后,选择有前途的个体进行昂贵适应度评价.实验结果表明,算法中所提出的代理模型可有效提高基于分类的代理辅助进化算法求解昂贵高维多目标优化问题的能力,且与目前流行的代理辅助进化算法相比,基于改进集成学习分类的代理辅助进化算法更具竞争力.     

结合全局和局部正则化的半监督二分类算法

针对在半监督分类问题中单独使用全局学习容易出现的在整个输入空间中较难获得一个优良的决策函数的问题,以及单独使用局部学习可在特定的局部区域内习得较好的决策函数的特点,提出了一种结合全局和局部正则化的半监督二分类算法。该算法综合全局正则项和局部正则项的优点,基于先验知识构建的全局正则项能平滑样本的类标号以避免局部正则项学习不充分的问题,通过基于局部邻域内样本信息构建的局部正则项使得每个样本的类标号具有理想的特性,从而构造出半监督二分类问题的目标函数。通过在标准二类数据集上的实验,结果表明所提出的算法其平均分类正确率和标准误差均优于基于拉普拉斯正则项方法、基于正则化拉普拉斯正则项方法和基于局部学习正则项方法。     

基于不平衡数据分类的人体姿态分类算法

针对人体姿态监测传感器所返回数据的不平衡性特点影响分类性能的问题,提出一种基于不平衡数据分类的人体姿态分类算法。根据姿态监测传感器所返回数据的特点,基于K-means的思想,提出一种噪声样本识别算法。针对样本集的不平衡性问题,本文通过引入经典的过采样算法SMOTE,对少数类样本集进行操作。利用Adaboost学习框架的优势,对平衡后的样本集进行训练,获得最终分类模型。选择G-mean、F-value及AUC为分类模型的评价指标,通过在ARe Mr人体姿态数据集上与三种经典的不平衡分类模型CUS-Boost、SMOTEBoost以及RUS-Boost算法相对比。验证了本文所提出的基于不平衡数据分类的人体姿态分类算法有效性、精准性。     

一种基于超光谱的血细胞分类方法*

对近红外—可见光范围内的超高光谱血液图像进行血细胞分类。不同于常见的血细胞识别方法,对血细胞的特征提取不但含有图像灰度特征,而且还包含了丰富的光谱特征,在分类方法上利用具有自适应能力的遗传算法和神经网络设计分类器进行血细胞的分类。实验结果表明,该法对背景点、红细胞和病变细胞核可取得比较好的识别结果。相对于10波段光谱和80波段高光谱而言,220波段的超光谱以增加运行时间为代价,取得了较好的分类结果。     

基于数据分类存储的云存储系统节能算法

云存储规模的不断扩大以及设计时对能耗因素的忽略使其日益暴露出高能耗低效率的问题,并且此问题已经成为制约云计算与大数据快速发展的一个主要瓶颈。已有研究大多采用将整个存储节点调整到低能耗模式以达到节能的目的。根据数据的重复性及访问规律,设计了基于数据分类的存储模型,将存储区域划分为热数据块区、冷数据块区与重复文件区,根据不同数据的重复性及活动因子特点进行分区存储。围绕新的存储模型,设计了适应节能的数据存储算法并建立了能耗模型。实验结果表明：当系统负载小于设定阈值时,新的存储模型能够提高存储系统25%左右的能耗利用率。     

Adaptive ensemble of classifiers with regularization for imbalanced data classification

The dynamic ensemble selection of classifiers is an effective approach for processing label-imbalanced data classifications. However, such a technique is prone to overfitting, owing to the lack of regularization methods and the dependence on local geometry of data. In this study, focusing on binary imbalanced data classification, a novel dynamic ensemble method, namely adaptive ensemble of classifiers with regularization (AER), is proposed, to overcome the stated limitations. The method solves the overfitting problem through a new perspective of implicit regularization. Specifically, it leverages the properties of stochastic gradient descent to obtain the solution with the minimum norm, thereby achieving regularization; furthermore, it interpolates the ensemble weights by exploiting the global geometry of data to further prevent overfitting. According to our theoretical proofs, the seemingly complicated AER paradigm, in addition to its regularization capabilities, can actually reduce the asymptotic time and memory complexities of several other algorithms. We evaluate the proposed AER method on seven benchmark imbalanced datasets from the UCI machine learning repository and one artificially generated GMM-based dataset with five variations. The results show that the proposed algorithm outperforms the major existing algorithms based on multiple metrics in most cases, and two hypothesis tests (McNemar’s and Wilcoxon tests) verify the statistical significance further. In addition, the proposed method has other preferred properties such as special advantages in dealing with highly imbalanced data, and it pioneers the researches on regularization for dynamic ensemble methods.     

VALIS: an evolutionary classification algorithm

VALIS is an effective and robust classification algorithm with a focus on understandability. Its name stems from Vote-ALlocating Immune System, as it evolves a population of artificial antibodies that can bind to the input data, and performs classification through a voting process. In the beginning of the training, VALIS generates a set of random candidate antibodies; at each iteration, it selects the most useful ones to produce new candidates, while the least, are discarded; the process is iterated until a user-defined stopping condition. The paradigm allows the user to get a visual insight of the learning dynamics, helping to supervise the process, pinpoint problems, and tweak feature engineering. VALIS is tested against nine state-of-the-art classification algorithms on six popular benchmark problems; results demonstrate that it is competitive with well-established black-box techniques, and superior in specific corner cases.     

一种基于概念重复性的数据流集成分类算法

目前关于概念漂移数据流的分类研究已经取得了许多成果,但大部分没有充分考虑到数据流中概念重复出现的情况,这将耗费大量的计算和内存资源,增加了分类错误的可能性。为此,基于概念的重复性提出了一种数据流集成分类算法,该算法运用集成分类思想处理数据流中的概念漂移,但在学习过程中不会将暂时失效的概念及对应基分类器删除,而是把它们的基本信息存储起来,方便以后调用,并可根据概念间的转换关系预测即将到来的概念,在提高分类精度的同时又提高了时间效率。实验结果验证了算法的有效性。     

Enhanced algorithm for high-dimensional data classification

Minimum class variance support vector machine (MCVSVM) and large margin linear projection (LMLP) classifier, in contrast with traditional support vector machine (SVM), take the distribution information of the data into consideration and can obtain better performance. However, in the case of the singularity of the within-class scatter matrix, both MCVSVM and LMLP only exploit the discriminant information in a single subspace of the within-class scatter matrix and discard the discriminant information in the other subspace. In this paper, a so-called twin-space support vector machine (TSSVM) algorithm is proposed to deal with the high-dimensional data classification task where the within-class scatter matrix is singular. TSSVM is rooted in both the non-null space and the null space of the within-class scatter matrix, takes full advantage of the discriminant information in the two subspaces, and so can achieve better classification accuracy. In the paper, we first discuss the linear case of TSSVM, and then develop the nonlinear TSSVM. Experimental results on real datasets validate the effectiveness of TSSVM and indicate its superior performance over MCVSVM and LMLP.     

代价敏感的KPCA-Stacking不均衡数据分类算法

代价敏感学习是解决不均衡数据分类问题的一个重要策略,数据特征的非线性也给分类带来一定困难,针对此问题,结合代价敏感学习思想与核主成分分析KPCA提出一种代价敏感的Stacking集成算法KPCA-Stacking.首先对原始数据集采用自适应综合采样方法(ADASYN)进行过采样并进行KPCA降维处理;其次将KNN、LD...     

High-dimensional imbalanced biomedical data classification based on P-AdaBoost-PAUC algorithm

The Journal of Supercomputing - High-dimensional imbalanced biomedical data has dual characteristics of high-dimensional and imbalanced distribution. It is important to improve classification...     

Imbalanced data classification based on improved EIWAPSO-AdaBoost-C ensemble algorithm

Applied Intelligence - Adaptive Boosting (AdaBoost) algorithm is a widely used ensemble learning algorithm. And it can effectively improve the classification performance of ordinary datasets when...     

基于支持向量机的不平衡数据分类算法的研究*

针对不平衡数据分类问题,提出了基于Smote与核函数修改相结合的算法。首先用Smote方法处理数 据,降低不平衡度;然后以黎曼几何为依据,利用保角变换,对核函数进行修改,提高支持向量机的分类泛化能 力;最后用修改后的支持向量机对新的数据进行处理。实验结果表明,这种方法能在保持整体正确率的前提下 有效地提高少数类样本的分类准确率。     

基于种族分类的进化算法

为克服进化算的早熟问题，提出了基于种族分类的进化算法（SEA），根据种族分类信息修正适应度，适应度修正与种族富饶程度、个体在种族中的地位和种族密度3个参数有关。应用SEA优化多峰函数以及多目标优化问题，结果表明，该算法可以大大增加个体的多样性，有效地克服了“早熟”现象，增大了搜索全局最优解的几率；该算法保留不同种族的优越性使得在优化多目标问题时，与目标函数的权重关系不大，可以获得多个非劣解，从而有效地得到非劣解集合。     

Sparse regularization for semi-supervised classification

Manifold regularization (MR) is a promising regularization framework for semi-supervised learning, which introduces an additional penalty term to regularize the smoothness of functions on data manifolds and has been shown very effective in exploiting the underlying geometric structure of data for classification. It has been shown that the performance of the MR algorithms depends highly on the design of the additional penalty term on manifolds. In this paper, we propose a new approach to define the penalty term on manifolds by the sparse representations instead of the adjacency graphs of data. The process to build this novel penalty term has two steps. First, the best sparse linear reconstruction coefficients for each data point are computed by the l¹-norm minimization. Secondly, the learner is subject to a cost function which aims to preserve the sparse coefficients. The cost function is utilized as the new penalty term for regularization algorithms. Compared with previous semi-supervised learning algorithms, the new penalty term needs less input parameters and has strong discriminative power for classification. The least square classifier using our novel penalty term is proposed in this paper, which is called the Sparse Regularized Least Square Classification (S-RLSC) algorithm. Experiments on real-world data sets show that our algorithm is very effective.     

A classification EM algorithm for binned data

A real-time flaw diagnosis application for pressurized containers using acoustic emissions is described. The pressurized containers used are cylindrical tanks containing fluids under pressure. The surface of the pressurized containers is divided into bins, and the number of acoustic signals emanating from each bin is counted. Spatial clustering of high density bins using mixture models is used to detect flaws. A dedicated EM algorithm can be derived to select the mixture parameters, but this is a greedy algorithm since it requires the numerical computation of integrals and may converge only slowly. To deal with this problem, a classification version of the EM (CEM) algorithm is defined, and using synthetic and real data sets, the proposed algorithm is compared to the CEM algorithm applied to classical data. The two approaches generate comparable solutions in terms of the resulting partition if the histogram is sufficiently accurate, but the algorithm designed for binned data becomes faster when the number of available observations is large enough.     

面向非平衡混合数据的改进计数最近邻分类算法

非平衡混合数据是指数据集中类别不同的样本在数量上存在着较大的差别;同时样本数据集中的数据是非单一的数据类型,即它包含多种类型,如数值型和文本型数据。在对混合型数据的分类算法中,计数最近邻分类算法（CwkNN）可以有效地对混合型数据进行分类,但该算法对数据的非平衡性处理效果不是太理想。在CwkNN的基础之上结合数据的非平衡性特点提出了基于全局密度和K-密度的分类算法来提高少数类样本的权重,从而提高数据的分类精确度。实验结果表明,全局密度分类算法和CwkNN算法的分类精度相当,K-局部密度分类算法在一定程度上提高了分类的精度。     

一种多分辨率数据流在线分类算法

提出一种能够适应数据流突变式概念变化的增量分类算法,采用网格技术对数据集特征向量进行量化,利用Haar小波多种分辨率的数据表示方式,基于最近邻技术发现测试点的合适类标签。在真实数据集上的测试证明,与已存在的数据流分类算法相比,提出的分类算法精度较高,具有很低的更新代价,适合数据流应用的需求。