In recent years, the utilization of machine learning and data mining techniques in anomaly-based intrusion detection systems (AIDSs) has received a great attention by both security research communities and intrusion detection system developers. To design and build an accurate and high-performance AIDS based on machine learning techniques, it is important to consider inherent constraints and requirements in the intrusion detection domain. The most important constraints are the imbalanced justify; LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt; unicode-bidi: embed; DIRECTION: ltr" Key Words Intrusion detection, incremental clustering, imbalanced data, stream ltr"