The primary method of detection of submerged submarines is sonar. We also see magnetic anomaly detectors used at close range.

Anomaly is a noun.

Misuse IDS trying to detect abnormal behavior by analyzing the given traffic and matching several rules. based on Analysis and comparison with the Rules the system can detect any attacks, such as matching signature pattern. this method is still not sufficient.

Anomaly IDS trying to detect anomalies when any deviation occur from the normal system. That means, using Data mining techniques such as Machine Learning, this techniques will study the system and build a profile to it, and then using certain classification algorithms it will monitor the traffic, any traffic that deviate from the original profile will be an anomaly. there are several methods applied in Anomaly IDS such as Clustering, Neural Network, Fuzzy logic and etc....

Summary: Misuse is limited but Anomaly is adaptive and can detect even early attacks.

I hope that help answering your question.

Regards

irregularity is the synonyms of anomaly

Anomaly means, essentially, irregularity. An example sentence would be: The anomaly of the necklace, is what she liked about it.