Simulate web user behavior

I'm attending my master degree and I'm working at my master thesis on detection of DDos attacks with statistical instruments. My tutor has told me, first of all, to emulate a single user activity surfing the web and replicate it in a second moment. After this, I will use a statistical instrument that my tutor has just developed on thisemulated traffic, for evaluating the accurance of results.
I'm in trouble with doing this task. I'm asking you if you could give me some indications also in terms of tools or source code, so I will understand how to do it.

Thank you, hope you'll understand it's very necessary for me.