Browsing by Author "Huang, Pei-Wen"

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AUTOMATIC SPEECH RECOGNITION FOR ACOUSTICAL ANALYSIS AND ASSESSMENT OF CANTONESE PATHOLOGICAL VOICE AND SPEECH
(2016)
Lee, Tan
;
Liu, Yuanyuan
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Huang, Pei-Wen
;
Chien, Jen-Tzung
;
Lam, Wang Kong
This paper describes the application of state-of-the-art automatic speech recognition (ASR) systems to objective assessment of voice and speech disorders. Acoustical analysis of speech has long been considered a promising approach to non-invasive and objective assessment of people. In the past the types and amount of speech materials used for acoustical assessment were very limited. With the ASR technology, we are able to perform acoustical and linguistic analyses with a large amount of natural speech from impaired speakers. The present study is focused on Cantonese, which is a major Chinese dialect. Two representative disorders of speech production are investigated: dysphonia and aphasia. ASR experiments are carried out with continuous and spontaneous speech utterances from Cantonese-speaking patients. The results confirm the feasibility and potential of using natural speech for acoustical assessment of voice and speech disorders, and reveal the challenging issues in acoustic modeling and language modeling of pathological speech.
Hybrid Accelerated Optimization for Speech Recognition
(2016-01-01)
Chien, Jen-Tzung
;
Huang, Pei-Wen
;
Lee, Tan
;
電機工程學系
;
Department of Electrical and Computer Engineering
Optimization procedure is crucial to achieve desirable performance for speech recognition based on deep neural networks (DNNs). Conventionally, DNNs are trained by using mini-batch stochastic gradient descent (SGD) which is stable but prone to be trapped into local optimum. A recent work based on Nesterov's accelerated gradient descent (NAG) algorithm is developed by merging the current momentum information into correction of SGD updating. NAG less likely jumps into local minimum so that convergence rate is improved. In general, optimization based on SGD is more stable while that based on NAG is faster and more accurate. This study aims to boost the performance of speech recognition by combining complimentary SGD and NAG. A new hybrid optimization is proposed by integrating the SGD with momentum and the NAG by using an interpolation scheme which is continuously run in each mini-batch according to the change rate of cost function in consecutive two learning epochs. Tradeoff between two algorithms can be balanced for mini-batch optimization. Experiments on speech recognition using CUSENT and Aurora-4 show the effectiveness of the hybrid accelerated optimization in DNN acoustic model.
VARIANCE REDUCTION FOR OPTIMIZATION IN SPEECH RECOGNITION
(2016)
Chien, Jen-Tzung
;
Huang, Pei-Wen
;
電機工程學系
;
Department of Electrical and Computer Engineering
Deep neural network (DNN) is trained according to a mini-batch optimization based on the stochastic gradient descent algorithm. Such a stochastic learning suffers from instability in parameter updating and may easily trap into local optimum. This study deals with the stability of stochastic learning by reducing the variance of gradients in optimization procedure. We upgrade the optimization from the stochastic dual coordinated ascent (SDCA) to the accelerated SDCA without duality (or dual-free ASDCA). This optimization incorporates the momentum method to accelerate the updating rule where the variance of gradients can be reduced. Using dual-free ASDCA, the optimization of dual function of SDCA in a form of convex loss is implemented by directly optimizing the primal function with respect to pseudo-dual parameters. The non-convex optimization in DNN training can be resolved and accelerated. Experimental results illustrate the reduction of training loss, variance of gradients and word error rate by using the proposed optimization for DNN speech recognition.