The linked paper is 4 years old. DNNs have been dominant in speech since 2012. No one uses GMM systems anymore.
Baidu's approach isn't even the best (IBM's system tends to beat theirs on accuracy, and google tends not to publish numbers on known benchmarks), it's notable mostly for its use of RNNs to do pronunciation and language modeling (although they also tack on a mod-KN LM).
The linked paper is 4 years old. DNNs have been dominant in speech since 2012. No one uses GMM systems anymore.
Baidu's approach isn't even the best (IBM's system tends to beat theirs on accuracy, and google tends not to publish numbers on known benchmarks), it's notable mostly for its use of RNNs to do pronunciation and language modeling (although they also tack on a mod-KN LM).