B.J.W. Dudzik
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22 records found
1
This thesis investigates whether MoE delivers that promise on dysarthric ASR, using the FastConformer-CTC Large encoder fine-tuned per fold on the TORGO and UASpeech corpora across 41 leave-one-speaker-out folds. Three research questions are addressed: how standard sparsely-gated MoE compares to a fine-tuned dense baseline (RQ1); what specialization the trained experts develop (RQ2); and whether either training-time supervision or inference-time router steering can push the model toward useful specialization (RQ3).
The answer to all three questions is negative. Five standard MoE configurations match but do not beat the fine-tuned dense baseline, and a parameter-equal follow-up shows that at equal feed-forward capacity, the MoE structure is actively worse than dense by up to 2.89 pp. The trained experts develop genuine functional specialization, but the axis of specialization is encoder depth, not speaker group or phonetic content: different layers prefer different expert pairs, and within any layer, routing is roughly content-independent and group-independent. Training-time supervision toward group-aware specialization collapses at inference, as the depth-based organization overrides the supervised partition. Inference-time router steering produces real per-speaker improvements under post-hoc selection of the bias strength, but neither of two deployment-realistic mechanisms for choosing that bias recovers the gain.
The MoE structure on this task does meaningful work, but not the work the task needs: it organizes the encoder’s computation along an axis the dense baseline already covers through its per-layer feed-forward weights. Routing-input variants, cross-architecture replication, and continual-learning extensions are flagged as the most direct follow-ups. ...
This thesis investigates whether MoE delivers that promise on dysarthric ASR, using the FastConformer-CTC Large encoder fine-tuned per fold on the TORGO and UASpeech corpora across 41 leave-one-speaker-out folds. Three research questions are addressed: how standard sparsely-gated MoE compares to a fine-tuned dense baseline (RQ1); what specialization the trained experts develop (RQ2); and whether either training-time supervision or inference-time router steering can push the model toward useful specialization (RQ3).
The answer to all three questions is negative. Five standard MoE configurations match but do not beat the fine-tuned dense baseline, and a parameter-equal follow-up shows that at equal feed-forward capacity, the MoE structure is actively worse than dense by up to 2.89 pp. The trained experts develop genuine functional specialization, but the axis of specialization is encoder depth, not speaker group or phonetic content: different layers prefer different expert pairs, and within any layer, routing is roughly content-independent and group-independent. Training-time supervision toward group-aware specialization collapses at inference, as the depth-based organization overrides the supervised partition. Inference-time router steering produces real per-speaker improvements under post-hoc selection of the bias strength, but neither of two deployment-realistic mechanisms for choosing that bias recovers the gain.
The MoE structure on this task does meaningful work, but not the work the task needs: it organizes the encoder’s computation along an axis the dense baseline already covers through its per-layer feed-forward weights. Routing-input variants, cross-architecture replication, and continual-learning extensions are flagged as the most direct follow-ups.
Retrospective Think-Aloud Data as a Window into Performance Trust
A Human-Agent Collaborative Game Study
Think-aloud data for automatic trust assessment
RTA x Morality
How Concurrent Think-Aloud Data Reflects a User's Morality Trust in an Agent
A Think-Aloud Study of Morality Trust in Human-Agent Collaboration
To address this gap, this thesis investigates under what conditions LLM-generated feature importance rankings agree with SHAP and LIME. To answer this, we trained XGBoost models on three datasets across different task types and dimensionalities: California Housing, Wine Quality, and Taiwan Bankruptcy Prediction. We then prompted two open-weight LLMs, Gemma 4 (31B) and GPT-OSS (120B), to rank which features are driving 100 individual predictions per dataset. For the prompting, we used five prompt templates derived from three approaches: text-driven prompts that provide feature names and task context, data-driven prompts that provide anonymized perturbed samples, and a novel mixed neighbors prompt that combines feature names with real contrastive neighboring samples. The rankings were compared against rankings from SHAP and LIME using Spearman correlation and top-k overlap.
We found that alignment is mainly dependent on the dataset characteristics and the information included in the prompt. The best setup on California Housing, mixed neighbors with Gemma, came close to the agreement between SHAP and LIME themselves (a Spearman correlation of 0.693 compared to 0.772). On Wine Quality, where SHAP and LIME are in slight agreement (0.226 Spearman correlation), most setups surpassed their agreement, with a text-driven prompt reaching 0.645 against SHAP. On Taiwan Bankruptcy Prediction, all setups stayed below the agreement between SHAP and LIME (at best 0.305 compared to 0.414), with data-driven prompts performing best. Across all three datasets, the choice of prompt template affected agreement more than the choice of LLM.
However, text-driven rankings often missed the most important feature of individual predictions, suggesting that their agreement comes largely from the LLM’s own domain knowledge rather than the sample’s feature values. Overall, LLM-generated rankings can offer a quick, rough estimate of which features are predictive, but are not able to completely replace traditional post-hoc explainers. In practice, LLMs are best suited as a first check when model access is restricted, while high-stakes decisions still require explanations computed from the model itself.
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To address this gap, this thesis investigates under what conditions LLM-generated feature importance rankings agree with SHAP and LIME. To answer this, we trained XGBoost models on three datasets across different task types and dimensionalities: California Housing, Wine Quality, and Taiwan Bankruptcy Prediction. We then prompted two open-weight LLMs, Gemma 4 (31B) and GPT-OSS (120B), to rank which features are driving 100 individual predictions per dataset. For the prompting, we used five prompt templates derived from three approaches: text-driven prompts that provide feature names and task context, data-driven prompts that provide anonymized perturbed samples, and a novel mixed neighbors prompt that combines feature names with real contrastive neighboring samples. The rankings were compared against rankings from SHAP and LIME using Spearman correlation and top-k overlap.
We found that alignment is mainly dependent on the dataset characteristics and the information included in the prompt. The best setup on California Housing, mixed neighbors with Gemma, came close to the agreement between SHAP and LIME themselves (a Spearman correlation of 0.693 compared to 0.772). On Wine Quality, where SHAP and LIME are in slight agreement (0.226 Spearman correlation), most setups surpassed their agreement, with a text-driven prompt reaching 0.645 against SHAP. On Taiwan Bankruptcy Prediction, all setups stayed below the agreement between SHAP and LIME (at best 0.305 compared to 0.414), with data-driven prompts performing best. Across all three datasets, the choice of prompt template affected agreement more than the choice of LLM.
However, text-driven rankings often missed the most important feature of individual predictions, suggesting that their agreement comes largely from the LLM’s own domain knowledge rather than the sample’s feature values. Overall, LLM-generated rankings can offer a quick, rough estimate of which features are predictive, but are not able to completely replace traditional post-hoc explainers. In practice, LLMs are best suited as a first check when model access is restricted, while high-stakes decisions still require explanations computed from the model itself.
Human vs AI: Recognising Teenage Speech
How good are humans at recognizing teenage speech samples compared to state-of-the-art AI-based automatic speech recognisers?
Comparing Human Listeners and Dutch ASR on Transcribing Child Speech
The Effect of Familiarity with Child Speech on Transcription Performance
A balanced set of 40 utterances were taken from the JASMIN database (speakers aged 7-11), and were transcribed by 20 humans (10 familiar with child speech (parent/caretaker) and 10 unfamiliar). Transcripts were also gathered from two state-of-the-art ASR systems (Google Telephony and a Conformer model). These transcripts were evaluated against reference transcripts using Word Error Rate (WER). Statistical significance was tested.
Results show that overall ASR transcription performance was comparable to human performance, and in some cases slightly, but not significantly, better. Familiar listeners did not outperform unfamiliar listeners. In fact, there was no significant performance difference between the two groups of humans. Within the 7-11 age range, no clear relationship between speaker age and WER was shown, but results were sensitive to sentence difficulty outliers and "speaker effects". ...
A balanced set of 40 utterances were taken from the JASMIN database (speakers aged 7-11), and were transcribed by 20 humans (10 familiar with child speech (parent/caretaker) and 10 unfamiliar). Transcripts were also gathered from two state-of-the-art ASR systems (Google Telephony and a Conformer model). These transcripts were evaluated against reference transcripts using Word Error Rate (WER). Statistical significance was tested.
Results show that overall ASR transcription performance was comparable to human performance, and in some cases slightly, but not significantly, better. Familiar listeners did not outperform unfamiliar listeners. In fact, there was no significant performance difference between the two groups of humans. Within the 7-11 age range, no clear relationship between speaker age and WER was shown, but results were sensitive to sentence difficulty outliers and "speaker effects".
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