Оптимизация конструкции ансамбля классификаторов: пример интеллектуального анализа образовательных данных

Abstract

The choosing the best prediction method of education results is major challenge of Educational Data Mining (EDM). This EDM paper compares the results of student's performance forecast produced by the individual binary classifiers (Naive Bayes, Decision Tree, Multi-Layer Perceptron, Nearest Neighbors, Support Vector Machine algorithms) and their ensembles, which are trained (tested) on dataset containing up to 38 input attributes (weekly attendance in mathematics, the intensity of study, interim assessment) of 84 (36) secondary school students from Nasiriyah, Iraq. The two-class school performance was predicted – passing or not passing on final exam. Three following stages of comparison were completed. Аt the first stage of the experiment, the dependence of classifiers from the input attributes was investigated. It was shown that the forecast accuracy rises from 61.1–77.7% when all 38 attributes were used, to 75.0–80.5%, if base classifier trained with five attributes pre-selected by Ranker Search method. Then, in second stage, to each of the basе classifier the AdaBoost M1 procedure has been applied and five homogenous ensembles were created. And only two of these ensembles demonstrated small rise of 3% in accuracy comparing to corresponding stand-alone classifier, but the overall maximal prediction accuracy of 80.5% stayed the same. Finally, comparing the accuracies of 77.7% and 83.3% achieved by the heterogeneous ensemble consisted of five simple voting base classifiers and by the heterogeneous meta-ensemble of five simple voting AdaBoost homogenous ensembles correspondingly, we conclude that improvement of the quality of the individual classifier or homogeneous ensembles allows to construct more powerful EDM prediction methods.