There are 8 round test, 45 min for each. First, there are 2 developer to ask me question about mathematics and programming, not quite hard but they are considering your basis. Such as how to calculate the Pi, and reverse a string. Then, followed by researchers to ask me my vision and other question related to your background. The researchers might ask question related to his own research. For example, a researcher ask me how to broadcast message to other node and avoid redundancy and collision, just because he is research in sensor network.