Incoherent training of deep neural networks to de-correlate bottleneck features for speech recognition
Bibliographic record
Abstract
Recently, the hybrid model combining deep neural network (DNN) with context-dependent HMMs has achieved some dramatic gains over the conventional GMM/HMM method in many speech recognition tasks. In this paper, we study how to compete with the state-of-the-art DNN/HMM method under the traditional GMM/HMM framework. Instead of using DNN as acoustic model, we use DNN as a front-end bottleneck (BN) feature extraction method to decorrelate long feature vectors concatenated from several consecutive speech frames. More importantly, we have proposed two novel incoherent training methods to explicitly de-correlate BN features in learning of DNN. The first method relies on minimizing coherence of weight matrices in DNN while the second one attempts to minimize correlation coefficients of BN features calculated in each mini-batch data in DNN training. Experimental results on a 70-hr Mandarin transcription task and the 309-hr Switchboard task have shown that the traditional GMM/HMMs using BN features can yield comparable performance as DNN/HMM. The proposed incoherent training can produce 2-3% additional gain over the baseline BN features. At last, the discriminatively trained GMM/HMMs using incoherently trained BN features have consistently surpassed the state-of-the-art DNN/HMMs in all evaluated tasks.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".