際に/際/際は => occasion, time N2
に[基「もと」]づいて/に[基「もと」]づき/に[基「もと」]づく => Based on A N2
Based, Focused, Depending on
[際「さい」]して/に([際「さい」]し)/に[際「さい」]しての => At the time of A (which starts now).. N2
Time, Situation
に基づいて => based on; on the basis of ~ N2
に際して => on the occasion of; at the time of ~ N2