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• An analysis of lexicographic optimization for feature selection and data classification. • Cooperative co-evolution for feature selection while the classifier hyperparameters are also being optimized. • Optimization of multiple objectives using a simple evolutionary algorithm. • A new lexicographic ranking methodology to compare the results of different feature selection methods. • Quite good results for real high-dimensional datasets. This paper starts with two hypotheses. The first one is that the simultaneous optimization of the hyperparameters regulating the classifier within a wrapper method, while the best subset of features is being determined, should improve the results with respect to those obtained with a pre-parameterized classifier. The second one is that solving these two problems can be formulated as a lexicographic optimization problem, allowing the use of a simple single-objective evolutionary algorithm to solve this multi-objective problem. The fitness function is of key importance for such wrapper methods. It is responsible for guiding the search towards potentially good solutions and it also consumes most of the runtime. Having these issues in mind, this paper also proposes a new lexicographic fitness function, designed to minimize the runtime of the algorithm and also to avoid over-fitting. Furthermore, the execution time and the quality of the results obtained by the wrapper procedure also depend on some algorithmic hyperparameters: the similarity thresholds used when comparing two different solutions lexicographically and the percentage of data samples used for validation during the training process. Thus, an experimental analysis has been carried out to find adequate values for these hyperparameters. Finally, the lexicographic cooperative co-evolutionary wrapper approach, using the new fitness function proposed in this paper, has been tested with several datasets belonging to the University of California, Irvine (UCI) repository and also with some real high-dimensional datasets, obtaining quite good results, compared to other state-of-the-art wrapper methods. The comparison has also been made lexicographically, with a new methodology proposed in this paper. [ABSTRACT FROM AUTHOR]

Sparse Bayesian learning (SBL) provides state-of-the-art performance in accuracy, sparsity and probabilistic prediction for classification. In SBL, the regularization priors are automatically determined that avoids an exhaustive hyperparameter selection by cross-validation. However, scalability to large problems is a drawback of SBL because of the inversion of a potentially enormous covariance matrix for updating the regularization priors in every iteration. This paper develops an approximate SBL algorithm called ARP-SBL, where the regularization priors are approximated without inverting the covariance matrix. Therefore, our approach can easily scale up to problems with large data size or feature dimension. It alleviates the long training time and high memory complexity in SBL. Based on ARP-SBL, two scalable nonlinear SBL models: scalable relevance vector machine (ARP-RVM) and scalable sparse Bayesian extreme learning machine (ARP-SBELM) are developed for problems of large data size and large feature size respectively. Experiments on a variety of benchmarks have shown that the proposed models are with competitive accuracy compared to existing methods while i) converging faster; ii) requiring thousands of times less memory; iii) without exhaustive regularized hyperparameter selection; and iv) easily scaling up to large data size and high dimensional features. [ABSTRACT FROM AUTHOR]

This paper investigates a new bacterial colony-based feature selection algorithm to improve the classification accuracy of customers for personalized products recommendation. An attribute learning strategy is developed in this study to update the feature related population. Specifically, the features can be weighted according to their historic contributions to both the individual- and group-based subsets. Additionally, the frequency of appearance is also recorded for the feature candidates to improve the diversity of feature distribution and avoid the over-fitting. Based on the weight-based feature indexes and frequency of appearance records, the performance of feature subsets are enhanced by replacing the features being repeatedly appeared in a same vector. To explore the feasibility of the proposed method for the missing feature problems, the objective of the optimization is to minimize the classification error using the acceptable number of features. K-Nearest Neighbor is employed as the learning technique to cooperate with the proposed feature selection method. The effectiveness of the proposed feature selection method is demonstrated by performing test on the datasets from UCI machine learning repository and real-world data from Amazon customer reviews of products. Compared with other seven feature selections methods, the proposed feature selection algorithm outperforms the other algorithms by achieving higher classification accuracy rate using smaller features. [ABSTRACT FROM AUTHOR]

Due to the influence of environment, data obtained in real world are not completely reliable sometimes. This paper focuses on tackling the feature selection problem with unreliable data. First, the problem is formulated as an multi-objective optimization one with two objectives: the reliability and the classification accuracy. Then, an effective multi-objective feature selection algorithm based on bare-bones particle swarm optimization is proposed by incorporating two new operators. One is a reinforced memory strategy, which is designed to overcome the degradation phenomenon of particles. Another is a hybrid mutation, which is designed to improve the search ability of the proposed algorithm. Finally, two state-of-the-art multi-objective optimization algorithms are also applied to this kind of problem, and comparison results suggest that the proposed algorithm is highly competitive for the feature selection problem with unreliable data. [ABSTRACT FROM AUTHOR]

Cancer is curable if it can be detected early. One way to detect cancer is by analyzing the change in expression of genes in the suspected tissue. Serial analysis of gene expression (SAGE) is a sequencing technique used for measuring the expression levels of genes. Cancer detection problem can be posed as binary classification problem like whether a tissue is cancerous or normal. SAGE libraries contain expression levels of thousands of genes which are the features. It is impossible to consider all these features for classification and also the general feature selection algorithms are not efficient with this data. In this paper, closed frequent itemset mining is proposed as a feature selection technique for identifying a small set of features which can distinguish the two classes efficiently. The performance of the proposed technique is evaluated on SAGE data related to breast tissue and a group of 26 genes are selected as best features. Two well known classifiers, extreme learning machine (ELM) and support vector machine (SVM), are used to evaluate the effectiveness of the selected features in classification and found that the proposed method works well with these classifiers. [ABSTRACT FROM AUTHOR]

Abstract: In machine learning the so-called curse of dimensionality, pertinent to many classification algorithms, denotes the drastic increase in computational complexity and classification error with data having a great number of dimensions. In this context, feature selection techniques try to reduce dimensionality finding a new more compact representation of instances selecting the most informative features and removing redundant, irrelevant, and/or noisy features. In this paper, we propose a filter-based feature selection method for working in the multiple-instance learning scenario called ReliefF-MI; it is based on the principles of the well-known ReliefF algorithm. Different extensions are designed and implemented and their performance checked in multiple instance learning. ReliefF-MI is applied as a pre-processing step that is completely independent from the multi-instance classifier learning process and therefore is more efficient and generic than wrapper approaches proposed in this area. Experimental results on five benchmark real-world data sets and 17 classification algorithms confirm the utility and efficiency of this method, both statistically and from the point of view of execution time. [Copyright &y& Elsevier]

Abstract: Mass spectrometry (MS)-based proteomics has been established as a standard way for biomarker discovery and early detection of disease from the proteome level. However, the data generated by MS technology are noisy, have a lot of redundancy, and most importantly have low sample-to-dimension ratio. Therefore, successful analysis of MS data heavily relies on the algorithmic and data mining techniques used to extract information. In this paper, we briefly discuss some of the commonly used algorithms applied to mass-to-charge (m/z) feature selection, and propose a k-means clustering based hybrid algorithm to address the high-dimension and high-correlation issues associated with this task. Our k-means clustering based hybrid algorithm incorporates the advantages of both filter- and wrapper-based feature selection algorithms. A special iterative procedure is introduced to overcome the instability of k-means clustering and genetic algorithm. By comparing the proposed hybrid system with several popular m/z feature selection algorithms using 10 different classifiers, we show that the proposed algorithm is able to select m/z features with lower correlation while achieving higher sample classification accuracies. The m/z feature selection results also indicate that the proposed hybrid algorithm is very stable despite its stochastic nature. [ABSTRACT FROM AUTHOR]

Abstract: Feature selection plays an important role in pattern classification. Its purpose is to remove redundant features from data set as many as possible. The presence of useless features may not only deteriorate the performance of learning algorithms, but also obscure important information (e.g., intrinsic structure) behind data. Along with new and emerging techniques, data sets in many domains are becoming larger and larger and many irrelevant features are often prevailing in these data sets. This, however, poses great challenges to traditional learning algorithms, such as low efficiency and over-fitting. Thus, it becomes apparent that an efficient technique is needed to eliminate redundant or irrelevant features from the data sets. Currently, many endeavors to cope with this problem have been attempted and various outstanding feature selection methods have been proposed. Unlike other selection methods, in this paper we propose a general scheme of boosting feature selection method using information metric. The primary characteristic of our method is that it exploits weight of data to select salient features. Furthermore, the weight of data will be dynamically changed after each candidate feature has been selected. Thus, the information criteria used in feature selector can exactly represent the relevant degree between features and the class labels. As a result, the selected feature subset has maximal relevance to the class labels. Simulation studies carried out on UCI data sets show that the classification performance achieved by our proposed method is better than those of other selection methods in most cases. [Copyright &y& Elsevier]