find the number of concurrent users in system at a given time

Hi All,

We have the ECC system in which we need to set up monitoring alert which should tell the following things.

1.The  number of concurrent users looged  currently in the system.

2. List of  transaction per hour or user activites with the counts

I want to know whether we have any standard report , function module or tcode through which we can achive this.

A quick response will be appreciated.

Thanks in advance.

Regards

Santosh