A TrAdaBoost Method for Detecting Multiple Subjects’ N200 and P300 Potentials Based on Cross-Validation and an Adaptive Threshold

2020 ◽  
Vol 30 (03) ◽  
pp. 2050009 ◽  
Author(s):  
Mengfan Li ◽  
Fang Lin ◽  
Guizhi Xu
Keyword(s):  
Information Transfer ◽  
Cross Validation ◽  
Area Under The Curve ◽  
Adaptive Threshold ◽  
Training Data ◽  
Support Vector ◽  
Training Methods ◽  
Information Transfer Rate ◽  
Traditional Training ◽  
Subject Specific

Traditional training methods need to collect a large amount of data for every subject to train a subject-specific classifier, which causes subjects fatigue and training burden. This study proposes a novel training method, TrAdaBoost based on cross-validation and an adaptive threshold (CV-T-TAB), to reduce the amount of data required for training by selecting and combining multiple subjects’ classifiers that perform well on a new subject to train a classifier. This method adopts cross-validation to extend the amount of the new subject’s training data and sets an adaptive threshold to select the optimal combination of the classifiers. Twenty-five subjects participated in the N200- and P300-based brain–computer interface. The study compares CV-T-TAB to five traditional training methods by testing them on the training of a support vector machine. The accuracy, information transfer rate, area under the curve, recall and precision are used to evaluate the performances under nine conditions with different amounts of data. CV-T-TAB outperforms the other methods and retains a high accuracy even when the amount of data is reduced to one-third of the original amount. The results imply that CV-T-TAB is effective in improving the performance of a subject-specific classifier with a small amount of data by adopting multiple subjects’ classifiers, which reduces the training cost.

scholarly journals DPWSS: differentially private working set selection for training support vector machines

2021 ◽  
Vol 7 ◽  
pp. e799
Author(s):  
Zhenlong Sun ◽  
Jing Yang ◽  
Xiaoye Li ◽  
Jianpei Zhang
Keyword(s):  
Differential Privacy ◽  
Training Data ◽  
Support Vector ◽  
Sensitive Information ◽  
Training Methods ◽  
Selection Algorithm ◽  
Personal Privacy ◽  
Training Support ◽  
Working Set Selection ◽  
Working Set

Support vector machine (SVM) is a robust machine learning method and is widely used in classification. However, the traditional SVM training methods may reveal personal privacy when the training data contains sensitive information. In the training process of SVMs, working set selection is a vital step for the sequential minimal optimization-type decomposition methods. To avoid complex sensitivity analysis and the influence of high-dimensional data on the noise of the existing SVM classifiers with privacy protection, we propose a new differentially private working set selection algorithm (DPWSS) in this paper, which utilizes the exponential mechanism to privately select working sets. We theoretically prove that the proposed algorithm satisfies differential privacy. The extended experiments show that the DPWSS algorithm achieves classification capability almost the same as the original non-privacy SVM under different parameters. The errors of optimized objective value between the two algorithms are nearly less than two, meanwhile, the DPWSS algorithm has a higher execution efficiency than the original non-privacy SVM by comparing iterations on different datasets. To the best of our knowledge, DPWSS is the first private working set selection algorithm based on differential privacy.

scholarly journals A HIGH-SPEED BRAIN SPELLER USING STEADY-STATE VISUAL EVOKED POTENTIALS

2014 ◽  
Vol 24 (06) ◽  
pp. 1450019 ◽  
Author(s):  
MASAKI NAKANISHI ◽  
YIJUN WANG ◽  
YU-TE WANG ◽  
YASUE MITSUKURA ◽  
TZYY-PING JUNG
Keyword(s):  
Steady State ◽  
Information Transfer ◽  
High Speed ◽  
Target Identification ◽  
Real Life ◽  
Stimulus Presentation ◽  
Training Data ◽  
Information Transfer Rate ◽  
Electroencephalogram Eeg ◽  
Visual Evoked

Implementing a complex spelling program using a steady-state visual evoked potential (SSVEP)-based brain–computer interface (BCI) remains a challenge due to difficulties in stimulus presentation and target identification. This study aims to explore the feasibility of mixed frequency and phase coding in building a high-speed SSVEP speller with a computer monitor. A frequency and phase approximation approach was developed to eliminate the limitation of the number of targets caused by the monitor refresh rate, resulting in a speller comprising 32 flickers specified by eight frequencies (8–15 Hz with a 1 Hz interval) and four phases (0°, 90°, 180°, and 270°). A multi-channel approach incorporating Canonical Correlation Analysis (CCA) and SSVEP training data was proposed for target identification. In a simulated online experiment, at a spelling rate of 40 characters per minute, the system obtained an averaged information transfer rate (ITR) of 166.91 bits/min across 13 subjects with a maximum individual ITR of 192.26 bits/min, the highest ITR ever reported in electroencephalogram (EEG)-based BCIs. The results of this study demonstrate great potential of a high-speed SSVEP-based BCI in real-life applications.

scholarly journals Separating Landslide Source and Runout Signatures with Topographic Attributes and Data Mining to Increase the Quality of Landslide Inventory

2020 ◽  
Vol 10 (19) ◽  
pp. 6652
Author(s):  
Jhe-Syuan Lai
Keyword(s):  
Data Mining ◽  
Area Under The Curve ◽  
Detailed Comparison ◽  
Remotely Sensed ◽  
Training Data ◽  
Landslide Inventory ◽  
Support Vector ◽  
Aerial Photos ◽  
Topographic Attributes ◽  
Modeling Strategy

Landslide sources and runout features of typical natural terrain landslides can be observed from a geotechnical perspective. Landslide sources are the major area of occurrences, whereas runout signatures reveal the subsequent phenomena caused by unstable gravity. Remotely sensed landslide detection generally includes runout areas, unless these results have been excluded manually through detailed comparison with stereo aerial photos and other auxiliary data. Areas detected using remotely sensed landslide detection can be referred to as “landslide-affected” areas. The runout areas should be separated from landslide-affected areas when upgrading landslide detections into a landslide inventory to avoid unreliable results caused by impure samples. A supervised data mining procedure was developed to separate landslide sources and runout areas based on four topographic attributes derived from a 10–m digital elevation model with a random forest algorithm and cost-sensitive analysis. This approach was compared with commonly used methods, namely support vector machine (SVM) and logistic regression (LR). The Typhoon Morakot event in the Laonong River watershed, southern Taiwan, was modeled. The developed models constructed using the limited training data sets could separate landslide source and runout signatures verified using the polygon and area constraint-based datasets. Furthermore, the performance of developed models outperformed SVM and LR algorithms, achieving over 80% overall accuracy, area under the curve of the receiver operating characteristic, user’s accuracy, and producer’s accuracy in most cases. The agreement of quantitative evaluations between the area sizes of inventory polygons for training and the predicted targets was also observed when applying the supervised modeling strategy.

scholarly journals The Study of Influence of Sound on Visual ERP-Based Brain Computer Interface

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1203 ◽  
Author(s):  
Guizhi Xu ◽  
Yuwei Wu ◽  
Mengfan Li
Keyword(s):  
Information Transfer ◽  
High Performance ◽  
Brain Computer Interface ◽  
Event Related Potential ◽  
Training Data ◽  
Computer Interface ◽  
Information Transfer Rate ◽  
High Workload ◽  
The One ◽  
Study Designs

The performance of the event-related potential (ERP)-based brain–computer interface (BCI) declines when applying it into the real environment, which limits the generality of the BCI. The sound is a common noise in daily life, and whether it has influence on this decline is unknown. This study designs a visual-auditory BCI task that requires the subject to focus on the visual interface to output commands and simultaneously count number according to an auditory story. The story is played at three speeds to cause different workloads. Data collected under the same or different workloads are used to train and test classifiers. The results show that when the speed of playing the story increases, the amplitudes of P300 and N200 potentials decrease by 0.86 μV (p = 0.0239) and 0.69 μV (p = 0.0158) in occipital-parietal area, leading to a 5.95% decline (p = 0.0101) of accuracy and 9.53 bits/min decline (p = 0.0416) of information transfer rate. The classifier that is trained by the high workload data achieves higher accuracy than the one trained by the low workload if using the high workload data to test the performance. The result indicates that the sound could affect the visual ERP-BCI by increasing the workload. The large similarity of the training data and testing data is as important as the amplitudes of the ERP on obtaining high performance, which gives us an insight on how make to the ERP-BCI generalized.

scholarly journals M167. MACHINE LEARNING CLASSIFICATION OF FIRST-EPISODE PSYCHOSIS USING CORTICAL THICKNESS IN A LARGE MULTICENTER MRI STUDY

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S200-S200
Author(s):  
Alessandro Pigoni ◽  
Dominic Dwyer ◽  
Letizia Squarcina ◽  
Stefan Borgwardt ◽  
Benedicto Crespo-Facorro ◽  
...  
Keyword(s):  
Machine Learning ◽  
Cortical Thickness ◽  
Cross Validation ◽  
Area Under The Curve ◽  
First Episode Psychosis ◽  
First Episode ◽  
Support Vector ◽  
Machine Learning Classification ◽  
Episode Psychosis ◽  
Dependent Variables

Abstract Background Machine learning classifications of first-episode psychosis (FEP) using neuroimaging have predominantly analyzed brain volumes. Some studies examined cortical thickness data, but most of them have used parcellation approaches with data from single sites, which limits claims of generalizability. To address these limitations, we conducted a large-scale, multi-site analysis of cortical thickness comparing parcellations and vertex-wise approaches. By leveraging the multi-site nature of the study, we further investigated how different demographical and site-dependent variables affected predictions. Finally, we assessed relationships between the predictions and clinical variables. Methods 428 subjects (147 females, mean age 27.14) with FEP and 448 (230 females, mean age 27.06) healthy controls were enrolled in 8 centers by the ClassiFEP group. All subjects underwent a structural MRI (sMRI) session and were clinically assessed. Cortical thickness parcellation (68 areas) and full cortical maps (20484 vertices) were extracted. Supervised (linear Support Vector Machine) classification was used to differentiate FEP from HC, within a repeated nested Cross-Validation (CV) framework through the NeuroMiner software. In both inner and outer CVs, a 10-fold CV cycle was employed. We performed repeated nested CV at the outer cross-validation cycle by randomly permuting the participants within their groups (10 permutations) and repeating the CV cycle for each of these permutations. As feature preprocessing, regression of covariates (age, sex, and site), Principal Component Analysis and Scaling were applied. All preprocessing steps were implemented within the CV. Further analyses were conducted by stratifying the sample for MRI scanner, sex and by performing random resampling with increasingly reduced sample sizes. Results Vertex-wise thickness maps outperformed parcellation-based methods with a balanced accuracy (BAC) of 66.2% and an Area Under the Curve of 72%, compared to a BAC of 59% and an Area Under the Curve of 61% obtained with the ROI-based approach. The two BACs were significantly different based on the McNemar’s Test. By stratifying our sample for MRI scanner, we increased the overall BAC to more than 70% and we also increased generalizability across sites. Temporal areas resulted the most influential regions in the classification. The predictive decision scores presented significant correlations with age at onset, duration of treatment and the presence of affective vs non-affective psychosis. Discussion Cortical thickness could represent a valid measure to classify FEP subjects, showing temporal areas as potential markers in the early stages of psychosis. The assessment of site-dependent variables allowed us to increase the across-site generalizability of the model, thus attempting to address an important machine learning limitation, especially in the framework of large multi-site cohort and big data analysis.

scholarly journals Wireless Stimulus-on-Device Design for Novel P300 Hybrid Brain-Computer Interface Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Chung-Hsien Kuo ◽  
Hung-Hsuan Chen ◽  
Hung-Chyun Chou ◽  
Ping-Nan Chen ◽  
Yu-Cheng Kuo
Keyword(s):  
Independent Living ◽  
Information Transfer ◽  
Spinal Cord Injuries ◽  
Support Vector ◽  
Svm Classifier ◽  
Bee Colony ◽  
Information Transfer Rate ◽  
Control Scheme ◽  
Interval Type ◽  
High Level

Improving the independent living ability of people who have suffered spinal cord injuries (SCIs) is essential for their quality of life. Brain-computer interfaces (BCIs) provide promising solutions for people with high-level SCIs. This paper proposes a novel and practical P300-based hybrid stimulus-on-device (SoD) BCI architecture for wireless networking applications. Instead of a stimulus-on-panel architecture (SoP), the proposed SoD architecture provides an intuitive control scheme. However, because P300 recognitions rely on the synchronization between stimuli and response potentials, the variation of latency between target stimuli and elicited P300 is a concern when applying a P300-based BCI to wireless applications. In addition, the subject-dependent variation of elicited P300 affects the performance of the BCI. Thus, an adaptive model that determines an appropriate interval for P300 feature extraction was proposed in this paper. Hence, this paper employed the artificial bee colony- (ABC-) based interval type-2 fuzzy logic system (IT2FLS) to deal with the variation of latency between target stimuli and elicited P300 so that the proposed P300-based SoD approach would be feasible. Furthermore, the target and nontarget stimuli were identified in terms of a support vector machine (SVM) classifier. Experimental results showed that, from five subjects, the performance of classification and information transfer rate were improved after calibrations (86.00% and 24.2 bits/ min before calibrations; 90.25% and 27.9 bits/ min after calibrations).

scholarly journals Hybrid feature selection approach to identify optimal features of profile metadata to detect social bots in Twitter

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eiman Alothali ◽  
Kadhim Hayawi ◽  
Hany Alashwal
Keyword(s):  
Feature Selection ◽  
Random Forest ◽  
Cross Validation ◽  
Performance Metrics ◽  
Area Under The Curve ◽  
Support Vector ◽  
Detection Systems ◽  
Vector Machines ◽  
Selection Approach ◽  
Feature Selection Approach

AbstractThe last few years have revealed that social bots in social networks have become more sophisticated in design as they adapt their features to avoid detection systems. The deceptive nature of bots to mimic human users is due to the advancement of artificial intelligence and chatbots, where these bots learn and adjust very quickly. Therefore, finding the optimal features needed to detect them is an area for further investigation. In this paper, we propose a hybrid feature selection (FS) method to evaluate profile metadata features to find these optimal features, which are evaluated using random forest, naïve Bayes, support vector machines, and neural networks. We found that the cross-validation attribute evaluation performance was the best when compared to other FS methods. Our results show that the random forest classifier with six optimal features achieved the best score of 94.3% for the area under the curve. The results maintained overall 89% accuracy, 83.8% precision, and 83.3% recall for the bot class. We found that using four features: favorites_count, verified, statuses_count, and average_tweets_per_day, achieves good performance metrics for bot detection (84.1% precision, 81.2% recall).

scholarly journals Analisis Sentimen Dewan Perwakilan Rakyat Dengan Algoritma Klasifikasi Berbasis Particle Swarm Optimization

2020 ◽  
Vol 5 (2) ◽  
pp. 61
Author(s):  
Anas Faisal ◽  
Yuris Alkhalifi ◽  
Achmad Rifai ◽  
Windu Gata
Keyword(s):  
Support Vector Machine ◽  
Particle Swarm Optimization ◽  
Cross Validation ◽  
Naive Bayes ◽  
Particle Swarm ◽  
Area Under The Curve ◽  
Naïve Bayes ◽  
Support Vector ◽  
Swarm Optimization ◽  
Fold Cross Validation

Penggunaan internet terutama media sosial telah menjadi bagian dari kehidupan bernegara. Hal ini salah satunya karena Anggota Dewan Perwakilan Rakyat Republik Indonesia (DPR RI) banyak yang menyampaikan ide, kebijakan maupun memberikan komentar atas kebijakan pemerintah melalui media sosial. Penelitian ini dilakukan untuk mengukur pendapat atau memisahkan antara sentimen positif dan sentimen negatif terhadap DPR RI. Data yang digunakan dalam penelitian ini didapatkan dengan melakukan crawling pada media sosial twitter. Penelitian dilakukan dengan menggunakan dua Algoritma yaitu Algoritma Support Vector Machine (SVM) dan Naive Bayes (NB). Kedua algoritma tersebut masing-masing dioptimasi menggunakan Particle Swarm Optimization (PSO). Hasil pengujian k-fold cross validation SVM dan NB mendapatkan nilai accuracy 71,04% dan 70,69% dengan nilai Area Under the Curve (AUC) 0,817 dan 0,661. Sedangkan hasil pengujian k-flod cross validation dengan menggunakan PSO, untuk SVM dan NB masing-masing mendapatkan nilai accuracy 75,03% dan 73,49% dengan nilai AUC 0,808 dan 0,719. Penggunaan PSO mampu meningkatkan nilai accuracy algoritma SVM sebesar 3,99% dan 2,8% pada algoritma NB. Hasil dari pengujian kedua algoritma tersebut nilai accuracy tertinggi adalah SVM dengan PSO sebesar 75,03%.

Local and Regional Hour-Ahead Forecasts of Solar Irradiance with Training Data Selection and Support Vector Regression

2016 ◽  
Vol 136 (12) ◽  
pp. 898-907 ◽  
Author(s):  
Joao Gari da Silva Fonseca Junior ◽  
Hideaki Ohtake ◽  
Takashi Oozeki ◽  
Kazuhiko Ogimoto
Keyword(s):  
Support Vector Regression ◽  
Solar Irradiance ◽  
Training Data ◽  
Data Selection ◽  
Support Vector ◽  
Training Data Selection

Combination of Support Vector Machine and K-Fold cross-validation for prediction of long-term degradation of the compressive strength of marine concrete

2018 ◽  
Vol 1 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Chunxiang Qian ◽  
Wence Kang ◽  
Hao Ling ◽  
Hua Dong ◽  
Chengyao Liang ◽  
...  
Keyword(s):  
Support Vector Machine ◽  
Environmental Factors ◽  
Cross Validation ◽  
Concrete Strength ◽  
Simulation Method ◽  
Support Vector ◽  
Svm Model ◽  
Artificial Neural Network Ann ◽  
Influence Degree ◽  
Fold Cross Validation

Support Vector Machine (SVM) model optimized by K-Fold cross-validation was built to predict and evaluate the degradation of concrete strength in a complicated marine environment. Meanwhile, several mathematical models, such as Artificial Neural Network (ANN) and Decision Tree (DT), were also built and compared with SVM to determine which one could make the most accurate predictions. The material factors and environmental factors that influence the results were considered. The materials factors mainly involved the original concrete strength, the amount of cement replaced by fly ash and slag. The environmental factors consisted of the concentration of Mg2+, SO42-, Cl-, temperature and exposing time. It was concluded from the prediction results that the optimized SVM model appeared to perform better than other models in predicting the concrete strength. Based on SVM model, a simulation method of variables limitation was used to determine the sensitivity of various factors and the influence degree of these factors on the degradation of concrete strength.

Sign in / Sign up

Export Citation Format

Share Document