The Sydney Synthetic Intellect Institute, or "Double SI," was a facility located in Sydney, Australia on planet Earth. "SSII" worked with the creation of AI constructs for the UNSC, theorising new approaches and calculating the details necessary for the creation of the AI, "Dumb" or "Smart". The experts at this institute created Jerrod, the first functional "micro" AI.
Dr. Catherine Halsey was familiar with this institute. It is not clear if she attended it or not, but the researchers there let her borrow Jerrod to use in the field before the events on Onyx. Jerrod was only supposed to live for a matter of days, but he rapidly stabilised and has exceeded all expectations.