Dear Mr. Mhmehadi,
You will be glad to know that before recruiting any new faculty member/Teacher DIU go through several steps which includes:
1. Writen Test
2. Viva Voce
Once a teacher can satisfy the recruitment committee in all the above mentioned sections he gets the chance to be appointed here. After their appointment a training session is organized for the new teachers. There a teacher is informed of all the rules and regulation, teaching system, examination system and so on. Teachers also exchange their feedback on how they can improve the teaching quality and system. So there should not be any problem with the new teachers. However exceptional case is always a possibility. So if any student feel that the new teacher is not able to take the class properly, he/she can approach the department head to share their problem. A detailed online teaching evaluation process is also implemented so that students can easily submit their feedback on their course teachers online from anywhere. you can find the guideline for the Online Teaching Evaluation in this forum too.
I hope the above mentioned information will clear your confusion.
Shah - Al - Mamun