“…Magill's results were further extended by Lainiotis, et al [315,183,179,182,180] to a recursive form, with an exact error covariance form, for vector measurements and arbitrary continuous and discrete parameters. Early works dealt only with estimation for systems with a time-invariant mode that is unknown (a nonrandom constant) or uncertain (a random variable, but not a random process), which led to the autonomous operations of conditional filtering [315,308,118,185]. Many reinventions, extensions, and applications of this generation can be found in the literature under various names, including the "partition (partitioned or partitioning) filter" [179,182,180,347], the "multiple model adaptive filter" [179,182], the "parallel processing algorithm" [7], the "multiple model adaptive estimator" [242], the "static multiple-model algorithm" [18,216], the "filter bank method" [65], the "self-tuning estimator" [65], the "operating regime approach" [156], and in the same spirit the "mixture of experts" [254,73].…”