Sequential Forward Selection Method Research Articles

A novel approach to predictor selection among large-scale climate indices for seasonal rainfall forecasting in small catchments

ABSTRACT Utilizing identical climate indices as predictors for all climate divisions within large basins may result in unreliable rainfall forecasts at the sub-basin scale. This study aimed to develop a new approach to identify the most effective predictors among large-scale climate indices for seasonal rainfall forecasting in small areas. The proposed approach combines a selective singular value decomposition method (SSVD) with a non-linear sequential forward selection method (NLSFS). Applying the new algorithm for seasonal rainfall forecasting within two climate divisions in Karkheh basin, Iran, indicated that the climate indices identified by the SSVD differed between the study areas. The combination of these indices exhibited a correlation with seasonal rainfall approximately 11% higher than those derived from the SVD method. Moreover, NLSFS significantly enhanced the forecast accuracy compared to the frequently employed linear sequential forward selection (SFS) method, and the optimal predictors chosen by the two methods differed across all seasons.

A hybrid sequential forward channel selection method for enhancing EEG-Based emotion recognition

ABSTRACT In recent times, EEG-based emotion recognition has gained significant attention in affective computing. One of the major challenges in designing an efficient EEG-based emotion-recognition framework lies in handling the high dimensionality of the data recorded from a large number of EEG electrodes. This paper develops a hybrid sequential forward channel selection (HSFCSER) based emotion-recognition method, which aims to identify the most relevant subset of EEG channels and thus reduces the dimensionality of data. In HSFCSER, the Fisher score is used as the filter method, and the wrapper method includes Support Vector Machine (SVM). Wavelet-based features are extracted from the selected optimal EEG channels, followed by the feature selection using a multi-objective genetic algorithm. The proposed method is evaluated on the DEAP database. The methodology identifies 1) two classes of emotions viz. Low/High Valence with an average accuracy of 91.25 ± 5.48% for subject-dependent and 89.38 ± 4.76% for subject-independent, and Low/High Arousal with an average accuracy of 89.92 ± 5.81% for subject-dependent and 86.32 ± 5.34% for subject-independent, and 2) four classes of emotions viz. High Valence-Low Arousal (HVLA), High Valence-High Arousal, Low Valence-Low Arousal, and Low Valence-High Arousal with 75.94 ± 11.07% for subject-dependent and 73.13 ± 8.17% for subject-independent. The efficient electrode positions for emotion recognition are also depicted. The reported results are better compared to the existing results in the literature. The source code of the proposed work is made available at https://github.com/shyammarjit/HSFCS.

A Comprehensive Analysis of Provider Fraud Detection through Machine Learning

This research paper presents a comprehensive analysis of healthcare provider fraud detection and analysis using machine learning, drawing insights from diverse literature surveys. The study employs a systematic approach to evaluate methodologies and insights from various academic fields. Leveraging the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, the research synthesizes findings from 27 relevant studies out of 450 articles. The focus lies on characterizing healthcare fraud, emphasizing addressing the limitations and gaps identified in existing literature. The paper introduces a Sequential Forward Selection (SFS) method and SMOTE oversampling for fraud detection, utilizing K-Nearest Neighbors, Artificial Neural Network, Linear Discriminant Analysis, and Gradient Boosting Machine, Classification using a bagging classifier and a stacking meta-estimator. It is recommended to use the Stacking aggregator because it is statistically significant. This study intends to offer insightful information to researchers, legislators, and healthcare practitioners by resolving issues with and gaps in existing methodologies.

Improving classification accuracy for separation of area under crops based on feature selection from multi-temporal images and machine learning algorithms

Timeliness, accurate, and frequent monitoring of area under crops are necessary for achieving food security. Therefore, the present study was conducted to improve the classification accuracy for the area under crops based on feature selection (FS) technique from multi-temporal Sentinel-1 and Sentinel-2 images in Shush County, Iran. To this end, the required pre-processing was performed on the images, and then features were extracted and categorized into four types of datasets with 78, 53, 65 features, for dataset 1 to 3 respectively. Dataset 4 is the result of integrating datasets 1, 2, and 3 with 194 features. The Sequential Forward Selection (SFS) method was used for the optimal FS, and Support Vector Machine (SVM) and Random Forest (RF) algorithms were used for the image classification. The results of FS by SFS method and SVM algorithm for datasets 1, 2, 3, and 4 showed that 15 features were optimal. The SFS method and RF algorithm determined the optimum feature number as 18, 19, 11, and 14 for datasets 1, 2, 3, and 4, respectively. The results of the RF algorithm performed on dataset 4 showed the highest Overall Accuracy (OA) and Kappa coefficient of 91.23% and 0.9, respectively. The results from this algorithm indicated that the type of input features affects the classification accuracy, so dataset 4 (compared to dataset 2) improved the classification with a difference in OA and kappa coefficient of approximately 2.5% and 0.03, respectively. According to the findings, it can be concluded that selecting the optimal number of features using the SFS method in the separation of area under crops is of high importance and improves the computational efficiency of the models and classification accuracy. The SFS result indicated that the higher accuracy could be achieved when less than 20 features recruited in classification.

Graph neural network for predicting the effective properties of polycrystalline materials: A comprehensive analysis

We develop a polycrystal graph neural network (PGNN) model for predicting the effective properties of polycrystalline materials, using the Li7La3Zr2O12 ceramic as an example. A large-scale dataset with >5000 different three-dimensional polycrystalline microstructures of finite-width grain boundary is generated by Voronoi tessellation and processing of the electron backscatter diffraction images. The effective ion conductivities and elastic stiffness coefficients of these microstructures are calculated by high-throughput physics-based simulations. The optimized PGNN model achieves a low error of <1.4% in predicting all three diagonal components of the effective Li-ion conductivity matrix, outperforming a linear regression model and two baseline convolutional neural network models. Sequential forward selection method is used to quantify the relative importance of selecting individual grain (boundary) features to improving the property prediction accuracy, through which both the critical and unwanted node (edge) feature can be determined. The extrapolation performance of the trained PGNN model is also investigated. The transfer learning performance is evaluated by using the PGNN model pretrained for predicting conductivities to predict the elastic properties of the same set of microstructures.:

Deep Learning Based Hybrid Intrusion Detection Systems to Protect Satellite Networks

Despite the fact that satellite-terrestrial systems have advantages such as high throughput, low latency, and low energy consumption, as well as low exposure to physical threats and natural disasters and cost-effective global coverage, their integration exposes both of them to particular security challenges that can arise due to the migration of security challenges from one to another. Intrusion Detection Systems (IDS) can also be used to provide a high level of protection for modern network environments such as satellite-terrestrial integrated networks (STINs). To optimize the detection performance of malicious activities in network traffic, four hybrid intrusion detection systems for satellite-terrestrial communication systems (SAT-IDSs) are proposed in this paper. All the proposed systems exploit the sequential forward feature selection (SFS) method based on random forest (RF) to select important features from the dataset that increase relevance and reduce complexity and then combine them with a machine learning (ML) or deep learning (DL) model; Random Forest (RF), Long Short-Term memory (LSTM), Artificial Neural Networks (ANN), and Gated Recurrent Unit (GRU). Two datasets—STIN, which simulates satellite networks, and UNSW-NB15, which simulates terrestrial networks—were used to evaluate the performance of the proposed SAT-IDSs. The experimental results indicate that selecting significant and crucial features produced by RF-SFS vastly improves detection accuracy and computational efficiency. In the first dataset (STIN), the proposed hybrid ML system SFS-RF achieved an accuracy of 90.5% after using 10 selected features, compared to 85.41% when using the whole dataset. Furthermore, the RF-SFS-GRU model achieved the highest performance of the three proposed hybrid DL-based SAT-IDS with an accuracy of 87% after using 10 selected features, compared to 79% when using the entire dataset. In the second dataset (UNSW-NB15), the proposed hybrid ML system SFS-RF achieved an accuracy of 78.52% after using 10 selected features, compared to 75.4% when using the whole dataset. The model with the highest accuracy of the three proposed hybrid DL-based SAT-IDS was the RF-SFS-GRU model. It achieved an accuracy of 79% after using 10 selected features, compared to 74% when using the whole dataset.

Proposing a Feature Selection Approach to Predict Learners' Performance in Virtual Learning Environments (VLEs)

Predicting students' success in virtual learning environments (VLEs) can help educational institutions improve their online services and provide efficient online learning content. However, this cannot be achieved without identifying the possible effective features that have a high influence on students' performance. This research aims at providing an early prediction approach to learners' achievement on VLEs. A new feature selection method called a Developed Sequential Feature Selection (D-SFS) was proposed to identify the most effective features that could highly enhance prediction accuracy. The findings suggest that the D-SFS method outperforms the original Sequential Forward Selection (SFS) approach. The prediction accuracy using the SFS method was 92.466% with seventeen features, whereas the proposed approach successfully predicted 92.518% of students' performance using seven features only. Such outcomes highlight the importance of implementing a feature selection method to enhance prediction accuracy, decrease the number of features, and reduce the model's time and execution complexity.

EmPDBA: protein-DNA binding affinity prediction by combining features from binding partners and interface learned with ensemble regression model.

Protein-deoxyribonucleic acid (DNA) interactions are important in a variety of biological processes. Accurately predicting protein-DNA binding affinity has been one of the most attractive and challenging issues in computational biology. However, the existing approaches still have much room for improvement. In this work, we propose an ensemble model for Protein-DNA Binding Affinity prediction (emPDBA), which combines six base models with one meta-model. The complexes are classified into four types based on the DNA structure (double-stranded or other forms) and the percentage of interface residues. For each type, emPDBA is trained with the sequence-based, structure-based and energy features from binding partners and complex structures. Through feature selection by the sequential forward selection method, it is found that there do exist considerable differences in the key factors contributing to intermolecular binding affinity. The complex classification is beneficial for the important feature extraction for binding affinity prediction. The performance comparison of our method with other peer ones on the independent testing dataset shows that emPDBA outperforms the state-of-the-art methods with the Pearson correlation coefficient of 0.53 and the mean absolute error of 1.11kcal/mol. The comprehensive results demonstrate that our method has a good performance for protein-DNA binding affinity prediction. Availability and implementation: The source code is available at https://github.com/ChunhuaLiLab/emPDBA/.

Explainable Machine Learning Approach for Hepatitis C Diagnosis Using SFS Feature Selection

Hepatitis C is a significant public health concern, resulting in substantial morbidity and mortality worldwide. Early diagnosis and effective treatment are essential to prevent the disease’s progression to chronic liver disease. Machine learning algorithms have been increasingly used to develop predictive models for various diseases, including hepatitis C. This study aims to evaluate the performance of several machine learning algorithms in diagnosing chronic liver disease, with a specific focus on hepatitis C, to improve the cost-effectiveness and efficiency of the diagnostic process. We collected a comprehensive dataset of 1801 patient records, each with 12 distinct features, from Jordan University Hospital. To assess the robustness and dependability of our proposed framework, we conducted two research scenarios, one with feature selection and one without. We also employed the Sequential Forward Selection (SFS) method to identify the most relevant features that can enhance the model’s accuracy. Moreover, we investigated the effect of the synthetic minority oversampling technique (SMOTE) on the accuracy of the model’s predictions. Our findings indicate that all machine learning models achieved an average accuracy of 83% when applied to the dataset. Furthermore, the use of SMOTE did not significantly affect the accuracy of the model’s predictions. Despite the increasing use of machine learning models in medical diagnosis, there is a growing concern about their interpretability. As such, we addressed this issue by utilizing the Shapley Additive Explanations (SHAP) method to explain the predictions of our machine learning model, which was specifically developed for hepatitis C prediction in Jordan. This work provides a comprehensive evaluation of various machine learning algorithms in diagnosing chronic liver disease, with a particular emphasis on hepatitis C. The results provide valuable insights into the cost-effectiveness and efficiency of the diagnostic process and highlight the importance of interpretability in medical diagnosis.

A Multi-level Random Forest Model-Based Intrusion Detection Using Fuzzy Inference System for Internet of Things Networks

Intrusion detection (ID) methods are security frameworks designed to safeguard network information systems. The strength of an intrusion detection method is dependent on the robustness of the feature selection method. This study developed a multi-level random forest algorithm for intrusion detection using a fuzzy inference system. The strengths of the filter and wrapper approaches are combined in this work to create a more advanced multi-level feature selection technique, which strengthens network security. The first stage of the multi-level feature selection is the filter method using a correlation-based feature selection to select essential features based on the multi-collinearity in the data. The correlation-based feature selection used a genetic search method to choose the best features from the feature set. The genetic search algorithm assesses the merits of each attribute, which then delivers the characteristics with the highest fitness values for selection. A rule assessment has also been used to determine whether two feature subsets have the same fitness value, which ultimately returns the feature subset with the fewest features. The second stage is a wrapper method based on the sequential forward selection method to further select top features based on the accuracy of the baseline classifier. The selected top features serve as input into the random forest algorithm for detecting intrusions. Finally, fuzzy logic was used to classify intrusions as either normal, low, medium, or high to reduce misclassification. When the developed intrusion method was compared to other existing models using the same dataset, the results revealed a higher accuracy, precision, sensitivity, specificity, and F1-score of 99.46%, 99.46%, 99.46%, 93.86%, and 99.46%, respectively. The classification of attacks using the fuzzy inference system also indicates that the developed method can correctly classify attacks with reduced misclassification. The use of a multi-level feature selection method to leverage the advantages of filter and wrapper feature selection methods and fuzzy logic for intrusion classification makes this study unique.

Machine Learning-Based Classification of Subjective Cognitive Decline, Mild Cognitive Impairment, and Alzheimer's Dementia Using Neuroimage and Plasma Biomarkers.

Alzheimer's disease (AD) progresses relentlessly from the preclinical to the dementia stage. The process begins decades before the diagnosis of dementia. Therefore, it is crucial to detect early manifestations to prevent cognitive decline. Recent advances in artificial intelligence help tackle the complex high-dimensional data encountered in clinical decision-making. In total, we recruited 206 subjects, including 69 cognitively unimpaired, 40 subjective cognitive decline (SCD), 34 mild cognitive impairment (MCI), and 63 AD dementia (ADD). We included 3 demographic, 1 clinical, 18 brain-image, and 3 plasma biomarker (Aß1-42, Aß1-40, and tau protein) features. We employed the linear discriminant analysis method for feature extraction to make data more distinguishable after dimension reduction. The sequential forward selection method was used for feature selection to identify the 12 best features for machine learning classifiers. We used both random forest and support vector machine as classifiers. The area under the receiver operative curve (AUROC) was close to 0.9 between diseased (combining ADD and MCI) and the controls. AUROC was higher than 0.85 between SCD and controls, 0.90 between MCI and SCD, and above 0.85 between ADD and MCI. We can differentiate between adjacent phases of the AD spectrum with blood biomarkers and brain MR images with the help of machine learning algorithms.

An interpretable stacking ensemble learning framework based on multi-dimensional data for real-time prediction of drug concentration: The example of olanzapine.

Background and Aim: Therapeutic drug monitoring (TDM) has evolved over the years as an important tool for personalized medicine. Nevertheless, some limitations are associated with traditional TDM. Emerging data-driven model forecasting [e.g., through machine learning (ML)-based approaches] has been used for individualized therapy. This study proposes an interpretable stacking-based ML framework to predict concentrations in real time after olanzapine (OLZ) treatment. Methods: The TDM-OLZ dataset, consisting of 2,142 OLZ measurements and 472 features, was formed by collecting electronic health records during the TDM of 927 patients who had received OLZ treatment. We compared the performance of ML algorithms by using 10-fold cross-validation and the mean absolute error (MAE). The optimal subset of features was analyzed by a random forest-based sequential forward feature selection method in the context of the top five heterogeneous regressors as base models to develop a stacked ensemble regressor, which was then optimized via the grid search method. Its predictions were explained by using local interpretable model-agnostic explanations (LIME) and partial dependence plots (PDPs). Results: A state-of-the-art stacking ensemble learning framework that integrates optimized extra trees, XGBoost, random forest, bagging, and gradient-boosting regressors was developed for nine selected features [i.e., daily dose (OLZ), gender_male, age, valproic acid_yes, ALT, K, BW, MONO#, and time of blood sampling after first administration]. It outperformed other base regressors that were considered, with an MAE of 0.064, R-square value of 0.5355, mean squared error of 0.0089, mean relative error of 13%, and ideal rate (the percentages of predicted TDM within ± 30% of actual TDM) of 63.40%. Predictions at the individual level were illustrated by LIME plots, whereas the global interpretation of associations between features and outcomes was illustrated by PDPs. Conclusion: This study highlights the feasibility of the real-time estimation of drug concentrations by using stacking-based ML strategies without losing interpretability, thus facilitating model-informed precision dosing.

Feature selection using Decomposed Mutual Information Maximization

Feature selection has been recognized for long as an important preprocessing technique to reduce dimensionality and improve the performance of regression and classification tasks. The class of sequential forward feature selection methods based on Mutual Information (MI) is widely used in practice, mainly due to its computational efficiency and independence from the specific classifier. A recent work introduced a theoretical framework for this class of methods which explains the existing proposals as approximations to an optimal target objective function. Such framework made clear the advantages and drawbacks of each proposal. Methods accounting for the redundancy of candidate features using a maximization function and considering the so-called complementary effect are among the best ones. However, they still penalize the complementarity, which is an important drawback. This paper proposes the Decomposed Mutual Information Maximization (DMIM) method, which keeps the good theoretical properties of the best methods proposed so far but overcomes the complementarity penalization by applying the maximization separately to the inter-feature and class-relevant redundancies. DMIM was extensively evaluated and compared with other methods, both theoretically and using two synthetic scenarios and 20 publicly available real datasets applied to specific classifiers. Our results show that DMIM achieves a better classification performance than the remaining forward feature selection methods based on MI.

Hybrid feature selection method for SVM classification and its application for fault diagnosis of wear and peeling in journal bearing with a little muddy water using long-term real data

Rotating machines are widely used as components of various industries around the world, and its normal operation of rotating machines is important. Thus, condition monitoring and fault diagnosis of rotating machines have considerable attention in recent years. Industrial statistics illustrate that 40% of total large machine breakdowns happened due to broken bearings, while for small machines, the analogous number reaches up to 90%. This study aimed at researching fault diagnosis of journal bearings using the support vector machine (SVM) method. The experimental systems of vertical and horizontal rotating shafts were developed. There was no adding any initial artificial failure in the bearing, and a little muddy water was used, and long-term vibration data in both systems were obtained in the normal operation of the machines until bearing damages occurred in the journal bearing (3-hour tests were conducted repeatedly and total 128 datasets for vertical shaft and 24 datasets for horizontal shaft were obtained). A feature selection method is focused, and a hybrid feature selection method by combining Fisher score (FS) and a sequential forward selection (SFS) method was proposed. Its accuracy and efficiency was proved experimentally with 97.14% and 100% for vertical shaft and 100% for horizontal shaft. Furthermore, as a result of the SVM model and hybrid feature selection method, the most important feature for journal bearing of horizontal rotor system was clarified as mean value of RMS, and only this feature can give good diagnosis result. It is useful suggestion in selecting the features for the fault diagnosis of horizontal rotating machines.

A novel speech emotion recognition method based on feature construction and ensemble learning.

In the field of Human-Computer Interaction (HCI), speech emotion recognition technology plays an important role. Facing a small number of speech emotion data, a novel speech emotion recognition method based on feature construction and ensemble learning is proposed in this paper. Firstly, the acoustic features are extracted from the speech signal and combined to form different original feature sets. Secondly, based on Light Gradient Boosting Machine (LightGBM) and Sequential Forward Selection (SFS) method, a novel feature selection method named L-SFS is proposed. And then, the softmax regression model is used to learn automatically the weights of the four single weak learners including Support Vector Machine (SVM), K-Nearest Neighbor (KNN), Extreme Gradient Boosting (XGBoost) and LightGBM. Lastly, based on the learned automatically weights and the weighted average probability voting strategy, an ensemble classification model named Sklex is constructed, which integrates the above four single weak learners. In conclusion, the method reflects the effectiveness of feature construction and the superiority and stability of ensemble learning, and gets good speech emotion recognition accuracy.

Classification of surface electromyography and gyroscopic signals of finger gestures acquired by Myo armband using machine learning methods

Gestures of the human hand can be identified through processing of surface electromyography (sEMG) signals. The human hand can perform many gestures via manipulation of the fingers. With correct classification of finger gestures, the mobility of a prosthetic hand can be increased and provide greater functionally. In this study, reliable classification was obtained for sEMG finger data acquired from a Myo armband placed on the lower forearm. In order to improve classification, gyroscopic signals, not previously used in other studies, were investigated in the sEMG finger data. Data was acquired from ten normal subjects using the Myo armband to identify 6 finger gestures: thumb, index finger, middle finger, little finger, ring finger and rest. Participants repeated each gesture thirty times. sEMG signals were preprocessed to extract features. 17 features were used in the feature matrix. By using the sequential forward feature selection method, the highest performance feature set was determined. Support Vector Machine, K-Nearest Neighbor and multilayer artificial neural network were used as classification algorithm. The classification was made using the Classification Learner Application and Neural Network Pattern Recognition Tool in Matlab®. The best performance with the features extracted only from sEMG data was 94.40% using the Artificial Neural Networks (ANN) method. The best performance with the features extracted from both sEMG and gyroscopic data was 96.30% (p-value < 0.05)with the ANN method. It is seen that gyroscopic signals can increase classification performance.

Sequential forward mother wavelet selection method for mental workload assessment on N-back task using photoplethysmography signals

The increasing demands of a cognitive task require additional brain resources. This demand, known as mental workload, can lead to deteriorated task performance. Therefore, assessment of mental workload can provide a proper working environment to promote the working efficiency or improve safety in high-risk working environments for a subject. In this study, we present a novel sequential forward mother wavelet selection method for three levels of mental workload assessment on N-back task using photoplethysmography (PPG) signals, which non-invasively measures the blood volume changes in the microvascular bed of tissue from the skin surface with a low-cost opto-electronic technique. The proposed method was successfully applied to a PPG dataset, which was recorded from 22 healthy subjects during an N-back task using a wearable sensor. Instead of using only one mother wavelet, the features were extracted from effective mother wavelet combinations by means of a sequential forward mother wavelet selection method. In this three-class problem, the highest classification accuracy (CA) rates were achieved with 10 s (s) PPG signal segments compared with the 6 s, and 8 s PPG signal segments. For the 10 s PPG signals segments the highest CA was obtained as 76.67% for Subject 20 and the average CA for all subjects was obtained as 65.76%. Furthermore, the proposed method provided 3.59% CA improvement in average. We believed that the proposed method could ensure a great alternative to conventional mental workload assessment techniques.

18F-FDG PET/CT Radiomics for Preoperative Prediction of Lymph Node Metastases and Nodal Staging in Gastric Cancer.

ObjectivesThe accurate assessment of lymph node metastases (LNMs) and the preoperative nodal (N) stage are critical for the precise treatment of patients with gastric cancer (GC). The diagnostic performance, however, of current imaging procedures used for this assessment is sub-optimal. Our aim was to investigate the value of preoperative 18F-FDG PET/CT radiomic features to predict LNMs and the N stage.MethodsWe retrospectively collected clinical and 18F-FDG PET/CT imaging data of 185 patients with GC who underwent total or partial radical gastrectomy. Patients were allocated to training and validation sets using the stratified method at a fixed ratio (8:2). There were 2,100 radiomic features extracted from the 18F-FDG PET/CT scans. After selecting radiomic features by the random forest, relevancy-based, and sequential forward selection methods, the BalancedBagging ensemble classifier was established for the preoperative prediction of LNMs, and the OneVsRest classifier for the N stage. The performance of the models was primarily evaluated by the AUC and accuracy, and validated by the independent validation methods. Analysis of the feature importance and the correlation were also conducted. We also compared the predictive performance of our radiomic models to that with the contrast-enhanced CT (CECT) and 18F-FDG PET/CT.ResultsThere were 185 patients—127 men, 58 women, with the median age of 62, and an age range of 22–86 years. One CT feature and one PET feature were selected to predict LNMs and achieved the best performance (AUC: 82.2%, accuracy: 85.2%). This radiomic model also detected some LNMs that were missed in CECT (19.6%) and 18F-FDG PET/CT (35.7%). For predicting the N stage, four CT features and one PET feature were selected (AUC: 73.7%, accuracy: 62.3%). Of note, a proportion of patients in the validation set whose LNMs were incorrectly staged by CECT (57.4%) and 18F-FDG PET/CT (55%) were diagnosed correctly by our radiomic model.ConclusionWe developed and validated two machine learning models based on the preoperative 18F-FDG PET/CT images that have a predictive value for LNMs and the N stage in GC. These predictive models show a promise to offer a potentially useful adjunct to current staging approaches for patients with GC.

Comparison of Filter and Wrapper Based Feature Selection Methods on Spam Comment Classification

The continuous growth of the internet has led to the use of social media for various purposes increase. For instance, some irresponsible parties take advantage of the comment feature on social media platforms to harm others by providing spam comments on the shared object. Furthermore, variation of comments creates many features to be processed, thereby negatively impacting the performance of a classification algorithm. Therefore, this study aims to solve the problem associated with spam comments by comparing filter and wrapper based feature selection using text classification techniques. Data collected from training and test data of 4944 and 100 comments showed that the best accuracy, precision, recall, and f-measure of MNB are 96%, 100%, 92%, and 95.8%. The best accuracy is achieved using feature selection by combining Chi-Square and Sequential Forward Selection methods with a subset of 500 features. Furthermore, the accuracy increase in the MNB and SVM classifications are 8% and 4%. This research concludes that the combination of feature selection improves the classification performance of Indonesian language spam comments.

Diagnosis of COVID-19 and non-COVID-19 patients by classifying only a single cough sound.

In the last month of 2019, a new virus emerged in China, spreading rapidly and affecting the whole world. This virus, which is called corona, is the most contagious type of virus that humanity has ever encountered. The virus has caused a huge crisis worldwide as it leads to severe infections and eventually death in humans. On March 11, 2020, it was announced by the World Health Organization that a COVID-19 outbreak has occurred. Computer-aided digital technologies, which eliminate many problems and provide convenience in people's lives, did not leave humanity alone in this regard and rushed to provide a solution for this unfortunate event. One of the important aspects in which computer-aided digital technologies can be effective is the diagnosis of the disease. Reverse transcription-polymerase chain reaction (RT-PCR), which is a standard and precise technique for diagnosing the disease, is an expensive and time-consuming method. Moreover, its availability is not the same all over the world. For this reason, it can be very attractive and important to distinguish the COVID-19 disease from a cold or flu through a cough sound analysis via smartphones which have entered into the lives of many people in recent years. In this study, we proposed a machine learning-based system to distinguish patients with COVID-19 from non-COVID-19 patients by analyzing only a single cough sound. Two different data sets were used, one accessible for the public and the other available on request. After combining the data sets, the features were obtained from the cough sounds using the mel-frequency cepstral coefficients (MFCCs) method, and then, they were classified with seven different machine learning classifiers. To determine the optimum values of hyperparameters for MFCCs and classifiers, the leave-one-out cross-validation (LOO-CV) strategy was implemented. Based on the results, the k-nearest neighbors classifier based on the Euclidean distance (kNN Euclidean) with the accuracy rate, sensitivity of COVID-19, sensitivity of non-COVID-19, F-measure, and area under the ROC curve (AUC) of 0.9833, 1.0000, 0.9720, 0.9799, and 0.9860, respectively, is more successful than other classifiers. Finally, the best and most effective features were determined for each classifier using the sequential forward selection (SFS) method. According to the results, the proposed system is excellent compared with similar studies in the literature and can be easily used in smartphones and facilitate the diagnosis of COVID-19 patients. In addition, since the used data set includes reflex and unconscious coughs, the results showed that conscious or unconscious coughing has no effect on the diagnosis of COVID-19 patients based on the cough sound.