Anomaly detection in Network data with unsupervised learning methods

Anomaly detection has become a crucial part of the protection of information and integrity. Due to the increase of cyber threats the demand for anomaly detection has grown for companies. Anomaly detection on time series data aims to detect unexpected behavior on the system. Anomalies often occur online, and companies need to be able to protect themselves from these intrusions. Multiple machine learning algorithms have been used and researched to solve the problem with anomaly detection and it is ongoing research to find the most optimal algorithms. Therefore, this study investigates algorithms such as K-means, Mean Shift and DBSCAN algorithm could be a solution for the problem. The study also investigates if combining the algorithms will improve the result. The results that the study reveals that the combinations of the algorithms perform slightly worse than the individual algorithms regarding speed and accuracy to detect anomalies. The algorithms without combinations did perform well during this study, they have slight differences between each other, and the results show the DBSCAN algorithm has slightly better total detection compared to the other algorithms and has slower execution time. The conclusion for this study reveals that the Mean Shift algorithm had the fastest execution time and the DBSCAN algorithm had the highest accuracy. The study also reveals most of the combinations between the algorithms did not improve during the fusion. However, the DBSCAN + Mean Shift fusion did improve the accuracy, and the K-means + Mean Shift fusion did improve the execution time