scholarly journals A comprehensive comparison on evolutionary feature selection approaches to classification

2021 ◽  
Author(s):  
Bing Xue ◽  
Mengjie Zhang ◽  
William Browne
Keyword(s):  
Feature Selection ◽  
Feature Selection Method ◽  
Classification Performance ◽  
Decision Makers ◽  
Computational Time ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Comprehensive Comparison ◽  
Single Objective

© 2015 Imperial College Press. Feature selection is an important data preprocessing step in machine learning and data mining, such as classification tasks. Research on feature selection has been extensively conducted for more than 50 years and different types of approaches have been proposed, which include wrapper approaches or filter approaches, and single objective approaches or multi-objective approaches. However, the advantages and disadvantages of such approaches have not been thoroughly investigated. This paper provides a comprehensive study on comparing different types of feature selection approaches, specifically including comparisons on the classification performance and computational time of wrappers and filters, generality of wrapper approaches, and comparisons on single objective and multi-objective approaches. Particle swarm optimization (PSO)-based approaches, which include different types of methods, are used as typical examples to conduct this research. A total of 10 different feature selection methods and over 7000 experiments are involved. The results show that filters are usually faster than wrappers, but wrappers using a simple classification algorithm can be faster than filters. Wrappers often achieve better classification performance than filters. Feature subsets obtained from wrappers can be general to other classification algorithms. Meanwhile, multi-objective approaches are generally better choices than single objective algorithms. The findings are not only useful for researchers to develop new approaches to addressing new challenges in feature selection, but also useful for real-world decision makers to choose a specific feature selection method according to their own requirements.

scholarly journals A comprehensive comparison on evolutionary feature selection approaches to classification

2021 ◽  
Author(s):  
Bing Xue ◽  
Mengjie Zhang ◽  
William Browne
Keyword(s):  
Feature Selection ◽  
Feature Selection Method ◽  
Classification Performance ◽  
Decision Makers ◽  
Computational Time ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Comprehensive Comparison ◽  
Single Objective

© 2015 Imperial College Press. Feature selection is an important data preprocessing step in machine learning and data mining, such as classification tasks. Research on feature selection has been extensively conducted for more than 50 years and different types of approaches have been proposed, which include wrapper approaches or filter approaches, and single objective approaches or multi-objective approaches. However, the advantages and disadvantages of such approaches have not been thoroughly investigated. This paper provides a comprehensive study on comparing different types of feature selection approaches, specifically including comparisons on the classification performance and computational time of wrappers and filters, generality of wrapper approaches, and comparisons on single objective and multi-objective approaches. Particle swarm optimization (PSO)-based approaches, which include different types of methods, are used as typical examples to conduct this research. A total of 10 different feature selection methods and over 7000 experiments are involved. The results show that filters are usually faster than wrappers, but wrappers using a simple classification algorithm can be faster than filters. Wrappers often achieve better classification performance than filters. Feature subsets obtained from wrappers can be general to other classification algorithms. Meanwhile, multi-objective approaches are generally better choices than single objective algorithms. The findings are not only useful for researchers to develop new approaches to addressing new challenges in feature selection, but also useful for real-world decision makers to choose a specific feature selection method according to their own requirements.

scholarly journals A Comprehensive Comparison on Evolutionary Feature Selection Approaches to Classification

2015 ◽  
Vol 14 (02) ◽  
pp. 1550008 ◽  
Author(s):  
Bing Xue ◽  
Mengjie Zhang ◽  
Will N. Browne
Keyword(s):  
Feature Selection ◽  
Feature Selection Method ◽  
Classification Performance ◽  
Decision Makers ◽  
Computational Time ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Comprehensive Comparison ◽  
Single Objective

Feature selection is an important data preprocessing step in machine learning and data mining, such as classification tasks. Research on feature selection has been extensively conducted for more than 50 years and different types of approaches have been proposed, which include wrapper approaches or filter approaches, and single objective approaches or multi-objective approaches. However, the advantages and disadvantages of such approaches have not been thoroughly investigated. This paper provides a comprehensive study on comparing different types of feature selection approaches, specifically including comparisons on the classification performance and computational time of wrappers and filters, generality of wrapper approaches, and comparisons on single objective and multi-objective approaches. Particle swarm optimization (PSO)-based approaches, which include different types of methods, are used as typical examples to conduct this research. A total of 10 different feature selection methods and over 7000 experiments are involved. The results show that filters are usually faster than wrappers, but wrappers using a simple classification algorithm can be faster than filters. Wrappers often achieve better classification performance than filters. Feature subsets obtained from wrappers can be general to other classification algorithms. Meanwhile, multi-objective approaches are generally better choices than single objective algorithms. The findings are not only useful for researchers to develop new approaches to addressing new challenges in feature selection, but also useful for real-world decision makers to choose a specific feature selection method according to their own requirements.

scholarly journals Particle Swarm Optimisation for Feature Selection in Classification

2021 ◽  
Author(s):  
◽  
Bing Xue
Keyword(s):  
Feature Selection ◽  
Classification Accuracy ◽  
Classification Performance ◽  
Classification Algorithm ◽  
Computational Time ◽  
Classification Algorithms ◽  
Multi Objective ◽  
Selection Approach ◽  
Feature Selection Approach ◽  
Single Objective

<p>Classification problems often have a large number of features, but not all of them are useful for classification. Irrelevant and redundant features may even reduce the classification accuracy. Feature selection is a process of selecting a subset of relevant features, which can decrease the dimensionality, shorten the running time, and/or improve the classification accuracy. There are two types of feature selection approaches, i.e. wrapper and filter approaches. Their main difference is that wrappers use a classification algorithm to evaluate the goodness of the features during the feature selection process while filters are independent of any classification algorithm. Feature selection is a difficult task because of feature interactions and the large search space. Existing feature selection methods suffer from different problems, such as stagnation in local optima and high computational cost. Evolutionary computation (EC) techniques are well-known global search algorithms. Particle swarm optimisation (PSO) is an EC technique that is computationally less expensive and can converge faster than other methods. PSO has been successfully applied to many areas, but its potential for feature selection has not been fully investigated.  The overall goal of this thesis is to investigate and improve the capability of PSO for feature selection to select a smaller number of features and achieve similar or better classification performance than using all features.  This thesis investigates the use of PSO for both wrapper and filter, and for both single objective and multi-objective feature selection, and also investigates the differences between wrappers and filters.  This thesis proposes a new PSO based wrapper, single objective feature selection approach by developing new initialisation and updating mechanisms. The results show that by considering the number of features in the initialisation and updating procedures, the new algorithm can improve the classification performance, reduce the number of features and decrease computational time.  This thesis develops the first PSO based wrapper multi-objective feature selection approach, which aims to maximise the classification accuracy and simultaneously minimise the number of features. The results show that the proposed multi-objective algorithm can obtain more and better feature subsets than single objective algorithms, and outperform other well-known EC based multi-objective feature selection algorithms.  This thesis develops a filter, single objective feature selection approach based on PSO and information theory. Two measures are proposed to evaluate the relevance of the selected features based on each pair of features and a group of features, respectively. The results show that PSO and information based algorithms can successfully address feature selection tasks. The group based method achieves higher classification accuracies, but the pair based method is faster and selects smaller feature subsets.  This thesis proposes the first PSO based multi-objective filter feature selection approach using information based measures. This work is also the first work using other two well-known multi-objective EC algorithms in filter feature selection, which are also used to compare the performance of the PSO based approach. The results show that the PSO based multiobjective filter approach can successfully address feature selection problems, outperform single objective filter algorithms and achieve better classification performance than other multi-objective algorithms.   This thesis investigates the difference between wrapper and filter approaches in terms of the classification performance and computational time, and also examines the generality of wrappers. The results show that wrappers generally achieve better or similar classification performance than filters, but do not always need longer computational time than filters. The results also show that wrappers built with simple classification algorithms can be general to other classification algorithms.</p>

scholarly journals Particle Swarm Optimisation for Feature Selection in Classification

2021 ◽  
Author(s):  
◽  
Bing Xue
Keyword(s):  
Feature Selection ◽  
Classification Accuracy ◽  
Classification Performance ◽  
Classification Algorithm ◽  
Computational Time ◽  
Classification Algorithms ◽  
Multi Objective ◽  
Selection Approach ◽  
Feature Selection Approach ◽  
Single Objective

<p>Classification problems often have a large number of features, but not all of them are useful for classification. Irrelevant and redundant features may even reduce the classification accuracy. Feature selection is a process of selecting a subset of relevant features, which can decrease the dimensionality, shorten the running time, and/or improve the classification accuracy. There are two types of feature selection approaches, i.e. wrapper and filter approaches. Their main difference is that wrappers use a classification algorithm to evaluate the goodness of the features during the feature selection process while filters are independent of any classification algorithm. Feature selection is a difficult task because of feature interactions and the large search space. Existing feature selection methods suffer from different problems, such as stagnation in local optima and high computational cost. Evolutionary computation (EC) techniques are well-known global search algorithms. Particle swarm optimisation (PSO) is an EC technique that is computationally less expensive and can converge faster than other methods. PSO has been successfully applied to many areas, but its potential for feature selection has not been fully investigated.  The overall goal of this thesis is to investigate and improve the capability of PSO for feature selection to select a smaller number of features and achieve similar or better classification performance than using all features.  This thesis investigates the use of PSO for both wrapper and filter, and for both single objective and multi-objective feature selection, and also investigates the differences between wrappers and filters.  This thesis proposes a new PSO based wrapper, single objective feature selection approach by developing new initialisation and updating mechanisms. The results show that by considering the number of features in the initialisation and updating procedures, the new algorithm can improve the classification performance, reduce the number of features and decrease computational time.  This thesis develops the first PSO based wrapper multi-objective feature selection approach, which aims to maximise the classification accuracy and simultaneously minimise the number of features. The results show that the proposed multi-objective algorithm can obtain more and better feature subsets than single objective algorithms, and outperform other well-known EC based multi-objective feature selection algorithms.  This thesis develops a filter, single objective feature selection approach based on PSO and information theory. Two measures are proposed to evaluate the relevance of the selected features based on each pair of features and a group of features, respectively. The results show that PSO and information based algorithms can successfully address feature selection tasks. The group based method achieves higher classification accuracies, but the pair based method is faster and selects smaller feature subsets.  This thesis proposes the first PSO based multi-objective filter feature selection approach using information based measures. This work is also the first work using other two well-known multi-objective EC algorithms in filter feature selection, which are also used to compare the performance of the PSO based approach. The results show that the PSO based multiobjective filter approach can successfully address feature selection problems, outperform single objective filter algorithms and achieve better classification performance than other multi-objective algorithms.   This thesis investigates the difference between wrapper and filter approaches in terms of the classification performance and computational time, and also examines the generality of wrappers. The results show that wrappers generally achieve better or similar classification performance than filters, but do not always need longer computational time than filters. The results also show that wrappers built with simple classification algorithms can be general to other classification algorithms.</p>

scholarly journals Differential evolution for filter feature selection based on information theory and feature ranking

2021 ◽  
Author(s):  
E Hancer ◽  
Bing Xue ◽  
Mengjie Zhang
Keyword(s):  
Feature Selection ◽  
Mutual Information ◽  
Differential Evolution ◽  
Nearest Neighbor ◽  
Feature Subset ◽  
Fisher Score ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Class Labels ◽  
Single Objective

© 2017 Elsevier B.V. Feature selection is an essential step in various tasks, where filter feature selection algorithms are increasingly attractive due to their simplicity and fast speed. A common filter is to use mutual information to estimate the relationships between each feature and the class labels (mutual relevancy), and between each pair of features (mutual redundancy). This strategy has gained popularity resulting a variety of criteria based on mutual information. Other well-known strategies are to order each feature based on the nearest neighbor distance as in ReliefF, and based on the between-class variance and the within-class variance as in Fisher Score. However, each strategy comes with its own advantages and disadvantages. This paper proposes a new filter criterion inspired by the concepts of mutual information, ReliefF and Fisher Score. Instead of using mutual redundancy, the proposed criterion tries to choose the highest ranked features determined by ReliefF and Fisher Score while providing the mutual relevance between features and the class labels. Based on the proposed criterion, two new differential evolution (DE) based filter approaches are developed. While the former uses the proposed criterion as a single objective problem in a weighted manner, the latter considers the proposed criterion in a multi-objective design. Moreover, a well known mutual information feature selection approach (MIFS) based on maximum-relevance and minimum-redundancy is also adopted in single-objective and multi-objective DE algorithms for feature selection. The results show that the proposed criterion outperforms MIFS in both single objective and multi-objective DE frameworks. The results also indicate that considering feature selection as a multi-objective problem can generally provide better performance in terms of the feature subset size and the classification accuracy. © This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

MULTI-OBJECTIVE EVOLUTIONARY ALGORITHMS FOR FILTER BASED FEATURE SELECTION IN CLASSIFICATION

2013 ◽  
Vol 22 (04) ◽  
pp. 1350024 ◽  
Author(s):  
BING XUE ◽  
LIAM CERVANTE ◽  
LIN SHANG ◽  
WILL N. BROWNE ◽  
MENGJIE ZHANG
Keyword(s):  
Feature Selection ◽  
Evaluation Criteria ◽  
Classification Performance ◽  
Classification Problems ◽  
Multi Objective ◽  
Conflicting Objectives ◽  
Benchmark Datasets ◽  
Selection Algorithms ◽  
Filter Algorithms ◽  
Single Objective

Feature selection is a multi-objective problem with the two main conflicting objectives of minimising the number of features and maximising the classification performance. However, most existing feature selection algorithms are single objective and do not appropriately reflect the actual need. There are a small number of multi-objective feature selection algorithms, which are wrapper based and accordingly are computationally expensive and less general than filter algorithms. Evolutionary computation techniques are particularly suitable for multi-objective optimisation because they use a population of candidate solutions and are able to find multiple non-dominated solutions in a single run. However, the two well-known evolutionary multi-objective algorithms, non-dominated sorting based multi-objective genetic algorithm II (NSGAII) and strength Pareto evolutionary algorithm 2 (SPEA2) have not been applied to filter based feature selection. In this work, based on NSGAII and SPEA2, we develop two multi-objective, filter based feature selection frameworks. Four multi-objective feature selection methods are then developed by applying mutual information and entropy as two different filter evaluation criteria in each of the two proposed frameworks. The proposed multi-objective algorithms are examined and compared with a single objective method and three traditional methods (two filters and one wrapper) on eight benchmark datasets. A decision tree is employed to test the classification performance. Experimental results show that the proposed multi-objective algorithms can automatically evolve a set of non-dominated solutions that include a smaller number of features and achieve better classification performance than using all features. NSGAII and SPEA2 outperform the single objective algorithm, the two traditional filter algorithms and even the traditional wrapper algorithm in terms of both the number of features and the classification performance in most cases. NSGAII achieves similar performance to SPEA2 for the datasets that consist of a small number of features and slightly better results when the number of features is large. This work represents the first study on NSGAII and SPEA2 for filter feature selection in classification problems with both providing field leading classification performance.

scholarly journals Particle swarm optimisation for feature selection: A hybrid filter-wrapper approach

2021 ◽  
Author(s):  
T Butler-Yeoman ◽  
Bing Xue ◽  
Mengjie Zhang
Keyword(s):  
Feature Selection ◽  
Classification Accuracy ◽  
Computational Cost ◽  
Particle Swarm ◽  
Classification Performance ◽  
Particle Swarm Optimisation ◽  
Computational Time ◽  
Advantages And Disadvantages ◽  
Benchmark Datasets ◽  
Selection Algorithms

© 2015 IEEE. Feature selection is an important pre-processing step, which can reduce the dimensionality of a dataset and increase the accuracy and efficiency of a learning/classification algorithm. However, existing feature selection algorithms mainly wrappers and filters have their own advantages and disadvantages. This paper proposes two filter-wrapper hybrid feature selection algorithms based on particle swarm optimisation (PSO), where the first algorithm named FastPSO combined filter and wrapper into the search process of PSO for feature selection with most of the evaluations as filters and a small number of evaluations as wrappers. The second algorithm named RapidPSO further reduced the number of wrapper evaluations. Theoretical analysis on FastPSO and RapidPSO is conducted to investigate their complexity. FastPSO and RapidPSO are compared with a pure wrapper algorithm named WrapperPSO and a pure filter algorithm named FilterPSO on nine benchmark datasets of varying difficulty. The experimental results show that both FastPSO and RapidPSO can successfully reduce the number of features and simultaneously increase the classification performance over using all features. The two proposed algorithms maintain the high classification performance achieved by WrapperPSO and significantly reduce the computational time, although the number of features is larger. At the same time, they increase the classification accuracy of FilterPSO and reduce the number of features, but increased the computational cost. FastPSO outperformed RapidPSO in terms of the classification accuracy and the number of features, but increased the computational time, which shows the trade-off between the efficiency and effectiveness. © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

BINARY PSO AND ROUGH SET THEORY FOR FEATURE SELECTION: A MULTI-OBJECTIVE FILTER BASED APPROACH

2014 ◽  
Vol 13 (02) ◽  
pp. 1450009 ◽  
Author(s):  
BING XUE ◽  
LIAM CERVANTE ◽  
LIN SHANG ◽  
WILL N. BROWNE ◽  
MENGJIE ZHANG
Keyword(s):  
Feature Selection ◽  
Rough Set ◽  
Rough Set Theory ◽  
Classification Performance ◽  
Classification Algorithms ◽  
Binary Particle Swarm Optimization ◽  
Traditional Methods ◽  
K Nearest Neighbors ◽  
Multi Objective ◽  
Single Objective

Feature selection is a multi-objective problem, where the two main objectives are to maximize the classification accuracy and minimize the number of features. However, most of the existing algorithms belong to single objective, wrapper approaches. In this work, we investigate the use of binary particle swarm optimization (BPSO) and probabilistic rough set (PRS) for multi-objective feature selection. We use PRS to propose a new measure for the number of features based on which a new filter based single objective algorithm (PSOPRSE) is developed. Then a new filter-based multi-objective algorithm (MORSE) is proposed, which aims to maximize a measure for the classification performance and minimize the new measure for the number of features. MORSE is examined and compared with PSOPRSE, two existing PSO-based single objective algorithms, two traditional methods, and the only existing BPSO and PRS-based multi-objective algorithm (MORSN). Experiments have been conducted on six commonly used discrete datasets with a relative small number of features and six continuous datasets with a large number of features. The classification performance of the selected feature subsets are evaluated by three classification algorithms (decision trees, Naïve Bayes, and k-nearest neighbors). The results show that the proposed algorithms can automatically select a smaller number of features and achieve similar or better classification performance than using all features. PSOPRSE achieves better performance than the other two PSO-based single objective algorithms and the two traditional methods. MORSN and MORSE outperform all these five single objective algorithms in terms of both the classification performance and the number of features. MORSE achieves better classification performance than MORSN. These filter algorithms are general to the three different classification algorithms.

scholarly journals Differential evolution for filter feature selection based on information theory and feature ranking

2021 ◽  
Author(s):  
E Hancer ◽  
Bing Xue ◽  
Mengjie Zhang
Keyword(s):  
Feature Selection ◽  
Mutual Information ◽  
Differential Evolution ◽  
Nearest Neighbor ◽  
Feature Subset ◽  
Fisher Score ◽  
Multi Objective ◽  
Advantages And Disadvantages ◽  
Class Labels ◽  
Single Objective

© 2017 Elsevier B.V. Feature selection is an essential step in various tasks, where filter feature selection algorithms are increasingly attractive due to their simplicity and fast speed. A common filter is to use mutual information to estimate the relationships between each feature and the class labels (mutual relevancy), and between each pair of features (mutual redundancy). This strategy has gained popularity resulting a variety of criteria based on mutual information. Other well-known strategies are to order each feature based on the nearest neighbor distance as in ReliefF, and based on the between-class variance and the within-class variance as in Fisher Score. However, each strategy comes with its own advantages and disadvantages. This paper proposes a new filter criterion inspired by the concepts of mutual information, ReliefF and Fisher Score. Instead of using mutual redundancy, the proposed criterion tries to choose the highest ranked features determined by ReliefF and Fisher Score while providing the mutual relevance between features and the class labels. Based on the proposed criterion, two new differential evolution (DE) based filter approaches are developed. While the former uses the proposed criterion as a single objective problem in a weighted manner, the latter considers the proposed criterion in a multi-objective design. Moreover, a well known mutual information feature selection approach (MIFS) based on maximum-relevance and minimum-redundancy is also adopted in single-objective and multi-objective DE algorithms for feature selection. The results show that the proposed criterion outperforms MIFS in both single objective and multi-objective DE frameworks. The results also indicate that considering feature selection as a multi-objective problem can generally provide better performance in terms of the feature subset size and the classification accuracy. © This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/

scholarly journals Particle swarm optimisation for feature selection: A hybrid filter-wrapper approach

2021 ◽  
Author(s):  
T Butler-Yeoman ◽  
Bing Xue ◽  
Mengjie Zhang
Keyword(s):  
Feature Selection ◽  
Classification Accuracy ◽  
Computational Cost ◽  
Particle Swarm ◽  
Classification Performance ◽  
Particle Swarm Optimisation ◽  
Computational Time ◽  
Advantages And Disadvantages ◽  
Benchmark Datasets ◽  
Selection Algorithms

© 2015 IEEE. Feature selection is an important pre-processing step, which can reduce the dimensionality of a dataset and increase the accuracy and efficiency of a learning/classification algorithm. However, existing feature selection algorithms mainly wrappers and filters have their own advantages and disadvantages. This paper proposes two filter-wrapper hybrid feature selection algorithms based on particle swarm optimisation (PSO), where the first algorithm named FastPSO combined filter and wrapper into the search process of PSO for feature selection with most of the evaluations as filters and a small number of evaluations as wrappers. The second algorithm named RapidPSO further reduced the number of wrapper evaluations. Theoretical analysis on FastPSO and RapidPSO is conducted to investigate their complexity. FastPSO and RapidPSO are compared with a pure wrapper algorithm named WrapperPSO and a pure filter algorithm named FilterPSO on nine benchmark datasets of varying difficulty. The experimental results show that both FastPSO and RapidPSO can successfully reduce the number of features and simultaneously increase the classification performance over using all features. The two proposed algorithms maintain the high classification performance achieved by WrapperPSO and significantly reduce the computational time, although the number of features is larger. At the same time, they increase the classification accuracy of FilterPSO and reduce the number of features, but increased the computational cost. FastPSO outperformed RapidPSO in terms of the classification accuracy and the number of features, but increased the computational time, which shows the trade-off between the efficiency and effectiveness. © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

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