regarding the instant attack scenario

[wonjeongchoi]

Hi, thank you for your great work.

I have a question in your attack scenario.
For instant attack scenario, the paper says that 'the attacker injects a set of malicious data into the t-th batch after adapting to the previous (t-1) benign batches'.

Does it mean that the attack is carried out only once (at t) throughout all batches (T)?
or it is done repeatedly for every t-th batch?

I have tried to find the setting of 't' in your experiments but I couldn't.
Could you please tell me how to set 't' in your instant attack experiments?

Thank you