Intrusion Detection Systems (IDSs) play a vital role in securing today's Data-Centric Networks. In a dynamic environment that is vulnerable to various types of attacks, novel, fast, and robust solutions are in demand to handle fast changing threats and thus the ever-increasing difficulty of detection. In this dissertation, we present a novel reinforcement learning based anomaly detection algorithm that further enables anomaly-based intrusion detection. As anomaly detection frameworks are mostly supervised learning based, which seeks the advantage of stable predictions and good performance with pre-recorded datasets, we have further explored the performance of a combined framework of joining a reinforcement learning algorithm with classimbalance techniques. The motivation of this approach is to not only exploit the auto-learning ability from the reinforcement learning loop, but also correct the classimbalance problem, which is pervasive in existing solutions. Our proposed solution is developed based on AE-RL [1]. We further introduce an adapted SMOTE to address the class-imbalance problem while remodel the behaviors of the environmental agent for better performance. Experiments are conducted using NSL-KDD [2] datasets.Comparative evaluation and their results are presented and analyzed. Using techniques such as SMOTE, ROS, NearMiss1 and NearMiss2, performance measures obtained from our simulations have led us to recognize specific performance trends.The proposed model AESMOTE outperforms the original AE-RL in several cases.Experiment results show an Accuracy greater than 0.82 and F1 greater than 0.824.