Hi Tuan,
Unfortunately, the ASA doesn't have any mechanism for scheduling syslog or NetFlow generation on a periodic schedule. The closest feature to this that you can use is Smart Call Home, which will let you create a profile that is run periodically. The profile can contain various commands that you want to run and you can have the ASA send you the output in an email. The following document has a few config examples for this:
https://supportforums.cisco.com/docs/DOC-14958
If that doesn't fit your needs, you'll need to use an external server that can collect data from the ASA and generate reports for you.
Hope that helps.
-Mike