Imbalanced Data Classification Algorithm Research Articles

An ImprovedD2GAN‐based oversampling algorithm for imbalanced data classification

AbstractTo address the problems of pattern collapse, uncontrollable data generation and high overlap rate when generative adversarial network (GAN) oversamples imbalanced data, we propose an imbalanced data oversampling algorithm based on improved dual discriminator generative adversarial nets (D2GAN). First, we integrate the positive class attribute information into the generator and the discriminator to ensure that the generator only generates the samples for positive class samples, which overcomes the problem of uncontrollable data generation by the generator. Second, we introduce a classifier into D2GAN for discriminating the generated samples and the original data, which avoids the overlap among the generated samples and the negative class samples, and ensures the diversity of the generated samples, the problem of pattern collapse is solved. Finally, the performance of the proposed algorithm is evaluated on 9 datasets by using SVM and neural network classification algorithm for oversampling experiments, the results show that the proposed algorithm effectively improve the classification performance of imbalanced data.

A Combined Priori and Purity Gaussian OverSampling Algorithm for Imbalanced Data Classification

A Combined Priori and Purity Gaussian OverSampling Algorithm for Imbalanced Data Classification

Conditional self-attention generative adversarial network with differential evolution algorithm for imbalanced data classification

Imbalanced data classification is an important research topic in real-world applications, like fault diagnosis in an aircraft manufacturing system. The over-sampling method is often used to solve this problem. It generates samples according to the distance between minority data. However, the traditional over-sampling method may change the original data distribution, which is harmful to the classification performance. In this paper, we propose a new method called Conditional Self-Attention Generative Adversarial Network with Differential Evolution (CSAGAN-DE) for imbalanced data classification. The new method aims at improving the classification performance of minority data by enhancing the quality of the generation of minority data. In CSAGAN-DE, the minority data are fed into the self-attention generative adversarial network to approximate the data distribution and create new data for the minority class. Then, the differential evolution algorithm is employed to automatically determine the number of generated minority data for achieving a satisfactory classification performance. Several experiments are conducted to evaluate the performance of the new CSAGAN-DE method. The results show that the new method can efficiently improve the classification performance compared with other related methods.

TSFNFR: Two-stage fuzzy neighborhood-based feature reduction with binary whale optimization algorithm for imbalanced data classification

Recently developed imbalanced data classification models are mainly focused on the majority class samples. In addition, several whale optimization-based feature reduction models are inefficient for high-dimensional data, readily fall into the local optimum, and are subject to difficulties associated with achieving a global optimal feature subset, due to high costs. To overcome the drawbacks, in this study, a two-stage feature reduction model using fuzzy neighborhood rough sets (FNRS) and the binary whale optimization algorithm (BWOA) was developed for imbalanced data classification. First, to indicate the sample fuzziness of mixed data, a similarity measure between samples based on fuzzy neighborhood was defined to investigate the similarity matrix and fuzzy neighborhood granule, and a new FNRS model was presented by constructing lower and upper approximations. By considering the uneven distribution of classes, the boundary-based feature significance measure was developed to minimize the influence of the uncertainty in boundary region for imbalanced data. Second, fuzzy neighborhood roughness and decision entropy were investigated based on FNRS, and by integrating these above measures, fuzzy neighborhood decision entropy was proposed to evaluate the fuzziness and roughness of the fuzzy neighborhood for imbalanced data. The external and internal significance metrics were proposed to achieve the preselected feature subset in the first stage. Third, in this second stage, a new control factor was defined to control the position of whales, and a novel fitness function was developed to evaluate the selected feature subset from imbalanced datasets. Thereafter, the immune regulation strategy of artificial immune was introduced into the BWOA to design the mixed selection probability, to divide the whale population. Two local interference strategies were applied to adjust the whale position and prevent BWOA trapped in the local optimum. Thus, an optimal feature subset was achieved by constantly iterating the BWOA. Finally, a two-stage feature reduction algorithm was designed to handle imbalanced and high-dimensional data, where the particle swarm optimization (PSO) algorithm was employed to determine the different optimized parameters for this two-stage algorithm. Experiments conducted on 22 datasets revealed that the proposed algorithm is efficient for two-class and multiclass datasets.

A novel oversampling and feature selection hybrid algorithm for imbalanced data classification

A novel oversampling and feature selection hybrid algorithm for imbalanced data classification

Adaptive Kernel Smote-Svm Algorithm for Imbalanced Data Classification

Adaptive Kernel Smote-Svm Algorithm for Imbalanced Data Classification

RB-CCR: Radial-Based Combined Cleaning and Resampling algorithm for imbalanced data classification

Real-world classification domains, such as medicine, health and safety, and finance, often exhibit imbalanced class priors and have asynchronous misclassification costs. In such cases, the classification model must achieve a high recall without significantly impacting precision. Resampling the training data is the standard approach to improving classification performance on imbalanced binary data. However, the state-of-the-art methods ignore the local joint distribution of the data or correct it as a post-processing step. This can causes sub-optimal shifts in the training distribution, particularly when the target data distribution is complex. In this paper, we propose Radial-Based Combined Cleaning and Resampling (RB-CCR). RB-CCR utilizes the concept of class potential to refine the energy-based resampling approach of CCR. In particular, RB-CCR exploits the class potential to accurately locate sub-regions of the data-space for synthetic oversampling. The category sub-region for oversampling can be specified as an input parameter to meet domain-specific needs or be automatically selected via cross-validation. Our 5times 2 cross-validated results on 57 benchmark binary datasets with 9 classifiers show that RB-CCR achieves a better precision-recall trade-off than CCR and generally out-performs the state-of-the-art resampling methods in terms of AUC and G-mean.

MMD-encouraging convolutional autoencoder: a novel classification algorithm for imbalanced data

Imbalanced data classification problem is widely existed in commercial activities and social production. It refers to the scenarios with considerable gap of sample amount among classes, thus significantly deteriorating the performance of the traditional classification algorithms. The previous dealing methods often focus on resampling and algorithm adjustment, but ignore enhancing the ability of feature learning. In this study, we have proposed a novel algorithm for imbalanced data classification: Maximum Mean Discrepancy-Encouraging Convolutional Autoencoder (MMD-CAE), from the perspective of feature learning. The algorithm adopts a two-phase target training process. The cross entropy loss is employed to calculate reconstruction loss of data, and the Maximum Mean Discrepancy (MMD) with intra-variance constraint is used to stimulate the feature discrepancy in bottleneck layer. By encouraging maximization of MMD between two-class samples, and mapping the original space to a higher dimension space via kernel skills, the features can be learned to form a more effective feature space. The proposed algorithm is tested on ten groups of samples with different imbalance ratios. The performance metrics of recall rate, F1 score, G-means and AUC verify that the proposed algorithm surpasses the existing state-of-the-art methods in this field, also with stronger generalization ability. This study could shed new lights on the related studies in terms of constituting more effective feature space via the proposed MMD with intra-variance constraint method, and the holistic MMD-CAE algorithm for imbalanced data classification.

An automatic sampling ratio detection method based on genetic algorithm for imbalanced data classification

Imbalanced data are a common phenomenon in both theoretical research and real-world applications. At a data level, standard classification algorithms cannot effectively learn and make predictions from imbalanced data, and this problem is generally solved by using oversampling, undersampling, or hybrid sampling methods. However, most of the current sampling methods use random sampling ratios, and the resulting classification performance can be undesirable and unstable. To obtain satisfactory and stable classification performance, we proposed three algorithms to automatically determine the sampling ratios for oversampling, undersampling, and hybrid sampling methods, based on a genetic algorithm. Experiments were performed to test the algorithms’ effectiveness by utilizing five widely used standard classification algorithms on 14 different imbalanced datasets using two oversampling, two undersampling, and four hybrid sampling methods. The statistical test results showed that for all five standard classification algorithms, sampling methods that used our proposed algorithms achieved the best classification results. Using area under the receiver operating characteristic curve (AUC) as the evaluation metric, it was demonstrated that the proposed algorithms for automatically determining the sampling ratio outperformed the random sampling ratio.

Imbalanced Data Classification Algorithm Based on Clustering and SVM

The class-imbalance learning is one of the most significant research topics in the data mining and machine learning. Imbalance problem means that one of the classes has much more samples than that of other classes. To deal with the issues of low classification accuracy and high time complexity, this paper proposes an novel imbalance data classification algorithm based on clustering and SVM. The algorithm suggests under-sampling in majority samples based on the distribution characteristics of minority samples. First, specific clusters are detected by cluster analysis on the minority. Second, a cluster boundary strategy is proposed to eliminate the bad influence of noise samples. To structure a balanced dataset for imbalance data, this paper proposes three principles of under-sampling on majority samples according to the characteristic of samples in the cluster. Finally, the optimal classification model from the linear combination of hybrid-kernel SVM is obtained. The experiments based on datasets in UCI and KEEL database show that our algorithm effectively decreases the interference of noise samples. Compared with the SMOTE and Fast-CBUS, the proposed algorithm not only reduces the feature dimension, but also improves the precision of the minor classes under the different labeled sample rates generally.

The detection of hospitalized patients at risk of testing positive to multi-drug resistant bacteria using MOCA-I, a rule-based “white-box” classification algorithm for medical data

BackgroundMulti-drug resistant (MDR) bacteria are a major health concern. In this retrospective study, a rule-based classification algorithm, MOCA-I (Multi-Objective Classification Algorithm for Imbalanced data) is used to identify hospitalized patients at risk of testing positive for multidrug-resistant (MDR) bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), before or during their stay. MethodsApplied to a data set of 48,945 hospital stays (including known cases of carriage) with up to 16,325 attributes per stay, MOCA-I generated alert rules for risk of carriage or infection. A risk score was then computed from each stay according to the triggered rules.Recall and precision curves were plotted. ResultsThe classification can be focused on specifically detecting high risk of having a positive test, or identifying large numbers of at-risk patients by modulating the risk score cut-off level. For a risk score above 0.85,recall (sensitivity) is 62 % with 69 % precision (confidence) for MDR bacteria, recall is 58 % with 88 % precision for MRSA. In addition, MOCA-I identifies 38 and 21 cases of previously unknown MDR and MRSA respectively. ConclusionsMOCA-I generates medically pertinent alert rules. This classification algorithm can be used to detect patients with high risk of testing positive to MDR bacteria (including MRSA). Classification can be modulated by appropriately setting the risk score cut-off level to favor specific detection of small numbers of patients at very high risk or identification of large numbers of patients at risk. MOCA-I can thus contribute to more adapted treatments and preventive measures from admission, depending on the clinical setting or management strategy.

K-Means Cluster Based Oversampling Algorithm for Imbalanced Data Classification

Imbalanced data classification problems endeavor to find a dependent variable in a skewed data distribution. Imbalanced data classification problems present in many application areas like, medical disease diagnosis, risk management, fault-detection, etc. It is a challenging problem in the field of machine learning and data mining. In this paper, K-Means cluster based oversampling algorithm is proposed to solve the imbalanced data classification problem. The experimental results show that the proposed algorithm outperforms the existing oversampling algorithms of previous studies.

Integrating TANBN with cost sensitive classification algorithm for imbalanced data in medical diagnosis

For the imbalanced classification problems, most traditional classification models only focus on searching for an excellent classifier to maximize classification accuracy with the fixed misclassification cost, not take into consideration that misclassification cost can change with sample probability distribution. So far as we know, cost-sensitive learning method can be effectively utilized to solve imbalanced data classification problems. In this regards, we propose an integrated TANBN with cost-sensitive classification algorithm (AdaC-TANBN) to overcome the above drawback and improve classification accuracy. The AdaC-TANBN algorithm employs variable misclassification cost determined by samples distribution probability to train classifier, then implements classification for imbalanced data in medical diagnosis. The effectiveness of our proposed approach is examined on the Cleveland heart dataset (Heart), Indian liver patient dataset (ILPD), Dermatology dataset and Cervical cancer risk factors dataset (CCRF) from the UCI learning repository. The experimental results indicate that the AdaC-TANBN algorithm can outperform other state-of-the-art comparative methods.

Improving k-Nearest Neighbors Algorithm for Imbalanced Data Classification

The k-Nearest Neighbors (k-NN) algorithm is a classic non-parametric method that has wide applications in data classification and prediction. Like many other machine learning schemes, the performance of k-NN classifiers will be significantly impacted by the imbalanced class distributions of data. That is, the data instances in the majority class tend to dominate the prediction of the test instances. In this paper, we look into the data pre-processing techniques that can be used to rebalance the training data and enhance the performance of k-NN classifiers in imbalanced data sets. We conduct extensive experiments on 14 real-world data sets collected from different application domains. We also perform statistical tests to verify the significance of different data pre-processing techniques in terms of boosting k-NN classification precision.

基于随机秩次k近邻规则的不平衡数据分类算法

基于随机秩次k近邻规则的不平衡数据分类算法

AUC4.5: AUC-Based C4.5 Decision Tree Algorithm for Imbalanced Data Classification

This paper presents a modification of Quinlan's C4.5 algorithm for imbalanced data classification. While the C4.5 algorithm uses the difference in information entropy to determine the goodness of a split, the proposed method, which is named AUC4.5, examines the difference in the area under the ROC curve (AUC) of a split. It implies that our method attempts to maximize the AUC value of a trained decision tree in order to cope with class imbalance in data. An extensive experimental study was performed on 20 real datasets from the machine learning repository at the University of California at Irvine, Irvine. The proposed AUC4.5 algorithm showed better classification than both the standard and cost-sensitive C4.5 algorithms.

Over-sampling algorithm for imbalanced data classification

Over-sampling algorithm for imbalanced data classification

A novel imbalanced data classification algorithm based on fuzzy rule

The classification of imbalanced data can increase the comprehensibility and expansibility of data and improve the efficiency of data classification. The accuracy of classification is poor when the data is classified by the current method for imbalanced data analysis of big data. To this end, this paper presents an imbalanced data classification algorithm based on fuzzy rule. The algorithm firstly collects the imbalanced data, selects the features of the imbalanced data, and optimises the imbalanced data classification algorithm by using the fuzzy rule classification algorithm. The experimental results show that when the classifier maintains a certain size of the weak classifier, the classification accuracy of the proposed algorithm will be gradually improved as the training time increases, and gradually be stable within a certain range of accuracy, this method can improve the accuracy of imbalanced data classification.

A novel imbalanced data classification algorithm based on fuzzy rule

A novel imbalanced data classification algorithm based on fuzzy rule

A GEV-Based Classification Algorithm for Imbalanced Data

A GEV-Based Classification Algorithm for Imbalanced Data