An Improved AdaBoost Cascade Classifier for Identifying Breath Signals of Liver Cancer
To reduce false negative rate of breath detection techniques in liver cancer screening,an improved AdaBoost cascade classifier was designed and applied to discriminate breath signals from healthy volunteers and liver cancer patients.First,a set of training subsets was obtained by self-help division of training samples.Based on the training subset,multiple sub-classifiers were successively obtained using different machine learning algorithms with K-fold cross-training and voting method.Next,multiple sub-classifiers were weighted and combined to obtain an improved AdaBoost classifier.Then,the training samples were self-subdivided and trained again with a new training subset to obtain another AdaBoost classifier.Finally,the two AdaBoost classifiers were concatenated in tandem to form a cascade classifier.After the test samples were fed into this cascade classifier,potentially anomalous samples were repeatedly screened according to the cascade rule.In this study,the relief-optimized feature set of the breath signals of 120 volunteers collected by the electronic nose(eNose)was used as the training sample to construct an improved AdaBoost cascade classifier and to discriminate the 40 test samples.The results showed that the classifier effectively distinguished the exhaled breath signals of liver cancer patients and healthy people in the test group,and the average sensitivity reached 93.42％,which was significantly better than the traditional AdaBoost cascade classifier,and the false negative rate was significantly reduced.In addition,the stability of this cascade classifier was good,and the coefficient of variation of the precision was only 3.95％.In conclusion,the improved AdaBoost cascade classifier effectively improved the classifier's discrimination accuracy of liver cancer breath signals,which was important for the study of breath-based noninvasive universal screening for liver cancers.
liver cancer breath testAdaBoost cascade classifierfalse negative ratecoefficient of variationrelief optimized feature set
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