How do you define AI?

To me, AI is like a machine that thinks and decides similar to a human.

Can you name at least three different sub-fields of AI?

Machine Learning, Robotics and Deep Learning

AI has been around since about 70 years so far. Why is it booming right now?

Nowdays, Computer are much stronger, which was not possible years later

Can you name at least three application sectors where robots are being largely employed? What are the reasons?

Can you identify three major challenges for a wheeled autonomous robot performing a 24h surveillance task in a large facility? (e.g., something like Mall of Qatar)

Maybe the ability to differentiate between intruders and normal people, as well as detect when something bad happens, like theft.