ODED: Outlier Detection in Educational Data

Abstract

Clustering data streams is one of the prominent tasks of discovering hidden patterns in data streams. It refers to the process of clustering newly arrived data into continuously and dynamically changing segmentation patterns. The current data stream clustering algorithms are lacking general clear steps for analysing new incoming data chunks. However, the majority of existing data stream solutions are adapting the clustering methods of static data to work with data stream setting. The main issue of concern is to propose a solution can improve the performance of existing approaches and present correct clusters and outliers. Data arriving in streams often contain outliers, which may have equal importance as clusters. Thus, it is desirable for data stream clustering algorithms to be able to detect the outliers as well as the clusters. The data stream clustering algorithms should be able to minimise the effects of noise and outliers data in a given dataset. This article presents a stream mining algorithm to cluster the data stream and monitor its evolution. Even though outlier detection is expected to be present in data streams, explicit outlier detection is rarely done in stream clustering algorithms. The proposed method is capable of explicit outlier detection and cluster evolution analysis. Relationship between outlier detection and the occurrence of physical events has been studied by applying the algorithm on the education data stream. Experiments led to the conclusion that the outlier detection accompanied by a change in the number of clusters indicates a significant education event. This kind of online monitoring and its results can be utilized in education systems in various ways. Viber education data streams produced by Viber groups are used to conduct this study.