5. The method of claim 3 , wherein the factored word sequence kernel has the general form: K n ⁡ ( s , t ) = ∑ I , J ⁢ ⁢ λ l ⁡ ( I ) + l ⁡ ( J ) ⁢ ∏ k = 1 n ⁢ ⁢ A ⁡ ( s i k , t j k ) where: S and t represent the first and second sequences; n represents a length of the shared subsequences to be used in the computation; I and J represent two of the subsequences of size n of indices ranging on the positions of the symbols in s and t respectively; λ represents an optional decay factor which weights gaps in non-contiguous sequences; l (I) represents the length, as the number of symbols plus any gaps, spanned by the subsequence I in s ; l (J) represents the length, as the number of symbols plus any gaps, spanned by the subsequence J in t, respectively; and A(s i k ,t j k ) is a function of two symbols s i k ,t j k in the sequences s and t respectively, the function quantifying the similarity between the two symbols according to the set of factors.
3. The method of claim 1 , wherein the computing a similarity measure comprises computing at least one factored word sequence kernel.