Before revision:  To address such challenges , we propose a conditional hidden Markov model (CHMM) . It inherits the hidden Markov model's ability to aggregating the labels from weak sources through unsupervised learning.
After revision:  To address this challenge , we propose a conditional hidden Markov model (CHMM) . It inherits the hidden Markov model's ability to aggregating the labels from weak sources through unsupervised learning.