In this section, speech recognition and 1000-best list rescoring experiments are conducted as configured in <cite>[4]</cite> . The maximum length of TRFs is m = 82, which is equal to the maximum length of the training sentences. The other configurations are: K = 300, β λ = 0.8, β ζ = 0.6, tc = 3000, t0 = 2000, tmax = 20, 000. L2 regularization with constant 4 × 10 −5 is used to avoid over-fitting. 6 CPU cores are used to parallelize the algorithm. The word error rates (WERs) and perplexities (PPLs) on WSJ'92 test set are shown in Tab.4.