Base on the concept of system s reliability,this paper makes a series of reliability index for urban mass transit(UMT) safety,clearly defines these indexes,such as operational reliability,operational maintainability,and operational availability,discusses the calculation method of them.

Countermeasures on the coastal wetland restoration of landscape channel in the north region of Songhuajiang River,Harbin City,northeastern China.;

Study on wetland restoration based on utilization of flood resources;

The paper gives the definition of restoration and wetland restoration.