In order to retain the integrity of application data, conflicting transactions have to be serialized. Some transactions are aborted and re-started to make transactions serializable. The EERO-AT (Energy-Efficient Role Ordering by considering Aborted Transactions) scheduler is proposed in our previous studies to reduce the execution time (ET) required for each re-started transaction to commit. However, as the number of transactions concurrently issued increases, the ET required to commit each re-started transaction becomes longer. In this study, the IEERO-AT (Improved EERO-AT) scheduler is proposed to furthermore reduce the ET of each re-started transaction by reducing the waiting time of each re-started transaction in a scheduling queue. We show the IEERO-AT scheduler reduces the ET of re-started transactions compared to the EERO-AT scheduler by using simulation.