Write in a brief about Knowledge management systems (KMS) as follows:
1-	introduction
2-	Definition and What is the system about?
3-	How it works (design)? (include 1 figure for illustration)
4-	What are the features of the system and its benefits and limitations?
5-	What are key management challenges involved in implementing the system?
6-	What are Its applications?
7-	Conclusion
8-	references