W.P. Brinkman
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42 records found
1
In this study, we investigate the relationships between these fragmentomic features in a genome-wide setting and evaluate their complementarity through multi-view intermediate integration for a binary classification task. Variance decomposition with correlation analysis showed that FSLR, MDS, and CNA capture partially non-redundant aspects of tumour-derived cfDNA signals, with only 7.2% overlap among outliers.
This biological complementarity did not translate into substantially improved predictive performance. The strongest downstream model was the PCA-based concatenation baseline using all three views, achieving an AUC of 0.969, with only marginal gains over CNA alone. In contrast, MOFA+ did not improve classification performance, reflecting a mismatch between its variance-maximization objective and cancer–healthy discrimination in cfDNA data. Similarly, Contrastive Multi-View Kernel Learning (CMK) failed to yield separable representations under an unsupervised objective, with meaningful class structure emerging only when supervision was introduced, yet still not surpassing the concatenation baseline.
Across all methods, CNA was consistently the most discriminative single feature, while FSLR provided an additional independent signal. MDS performed worst in all settings and contributed little to predictive performance. This limited contribution may reflect the chosen 5 Mb resolution rather than an inherent lack of biological signal, suggesting that feature-specific resolution optimization should be considered prior to integration. ...
In this study, we investigate the relationships between these fragmentomic features in a genome-wide setting and evaluate their complementarity through multi-view intermediate integration for a binary classification task. Variance decomposition with correlation analysis showed that FSLR, MDS, and CNA capture partially non-redundant aspects of tumour-derived cfDNA signals, with only 7.2% overlap among outliers.
This biological complementarity did not translate into substantially improved predictive performance. The strongest downstream model was the PCA-based concatenation baseline using all three views, achieving an AUC of 0.969, with only marginal gains over CNA alone. In contrast, MOFA+ did not improve classification performance, reflecting a mismatch between its variance-maximization objective and cancer–healthy discrimination in cfDNA data. Similarly, Contrastive Multi-View Kernel Learning (CMK) failed to yield separable representations under an unsupervised objective, with meaningful class structure emerging only when supervision was introduced, yet still not surpassing the concatenation baseline.
Across all methods, CNA was consistently the most discriminative single feature, while FSLR provided an additional independent signal. MDS performed worst in all settings and contributed little to predictive performance. This limited contribution may reflect the chosen 5 Mb resolution rather than an inherent lack of biological signal, suggesting that feature-specific resolution optimization should be considered prior to integration.
Improving Automatic Speech Recognition for Dutch Children with Developmental Language Disorder using Synthetic Data
Synthetic Speech Augmentation Using Text-to-Speech
Our results demonstrate that applying a moderate probability of linguistically motivated DLD transformations significantly outperforms standard, error-free childlike synthetic speech. Despite this relative linguistic success, the synthetic fine-tuning did not surpass the absolute performance of the unadapted zero-shot baseline. Furthermore, experiments indicate that scaling synthetic speaker variability introduces disruptive generation artifacts rather than improving model robustness. These findings demonstrate the validity of targeted linguistic simulation for atypical speech while exposing the severe acoustic limitations of current zero-shot TTS models in clinical, data-scarce domains. ...
Our results demonstrate that applying a moderate probability of linguistically motivated DLD transformations significantly outperforms standard, error-free childlike synthetic speech. Despite this relative linguistic success, the synthetic fine-tuning did not surpass the absolute performance of the unadapted zero-shot baseline. Furthermore, experiments indicate that scaling synthetic speaker variability introduces disruptive generation artifacts rather than improving model robustness. These findings demonstrate the validity of targeted linguistic simulation for atypical speech while exposing the severe acoustic limitations of current zero-shot TTS models in clinical, data-scarce domains.
Gaining and Visualizing Mental Health Insights from Self-Report Data
Presentation of Insights from ESM Data into Client Conditions for Practitioners
Visualizing Self-Report Data for Clinical Insight
Practitioner Perspectives on ESM Feedback for Assessing Therapy Effectiveness
Objective: This study aimed to explore how ESM data can be visualized to effectively communicate treatment effectiveness to mental health practitioners.
Methodology: A design-based approach was used to guide the development of two ESM visualizations. Visualization 1 consisting of a single temporal line graph and Visualization 2 consisting of a dashboard-style layout with four graphs. Practitioners, psychology students and medicine students completed a questionnaire evaluating the clarity, interpretability, and perceived clinical utility of the visualizations. Thematic analysis was conducted on the responses.
Results: Analysis of the responses from ten participants revealed four themes: (1) preference for single temporal line graphs due to their clarity and intuitive presentation of change over time, (2) usability challenges in complex dashboards, particularly with dual axes and ambiguous terminology, (3) value of contextual variables, such as interactions and homework completion, in understanding therapy progress and (4) a strong desire for customization to fit client-specific needs.
Conclusion: Clear visualizations of ESM data may support practitioners in assessing therapy effectiveness, especially when they enable reasoning about both therapeutic change and contextual influences. However, individual differences in interpretation underscore the need for flexibility and customizability.
...
Objective: This study aimed to explore how ESM data can be visualized to effectively communicate treatment effectiveness to mental health practitioners.
Methodology: A design-based approach was used to guide the development of two ESM visualizations. Visualization 1 consisting of a single temporal line graph and Visualization 2 consisting of a dashboard-style layout with four graphs. Practitioners, psychology students and medicine students completed a questionnaire evaluating the clarity, interpretability, and perceived clinical utility of the visualizations. Thematic analysis was conducted on the responses.
Results: Analysis of the responses from ten participants revealed four themes: (1) preference for single temporal line graphs due to their clarity and intuitive presentation of change over time, (2) usability challenges in complex dashboards, particularly with dual axes and ambiguous terminology, (3) value of contextual variables, such as interactions and homework completion, in understanding therapy progress and (4) a strong desire for customization to fit client-specific needs.
Conclusion: Clear visualizations of ESM data may support practitioners in assessing therapy effectiveness, especially when they enable reasoning about both therapeutic change and contextual influences. However, individual differences in interpretation underscore the need for flexibility and customizability.
Visualizing ESM Data to Support Mental Health Symptom Identification and Intervention Planning
Exploring Visualization Strategies for Clinical Insight
This research conducted a quasi-experiment with 122 second-grade students from a Havo/Vwo high school during a course on Google Spreadsheets. The experimental group had access to a button that let the computer instantly check their homework and provide feedback, while the control group did not. At the end of the course, students in the experimental group completed a questionnaire to share their experiences.
This research found no significant effects of the intervention on behavioral student engagement and learning outcomes, nor was a mediated relationship established. However, students did report several cognitive and metacognitive benefits. Namely: enhanced motivation, enhanced self-regulated learning, enhanced autonomy, feedback that helped them move forward and an improved understanding of the material. On the other hand, they reported some downsides. Namely: increased time consumption, a lack of added value and a lack of feedback quality.
Since this research did not find effects of computer assisted formative assessment similar to those observed in other subject areas, it raises the question of whether the subject domain of digital tooling interacts differently with this type of intervention. Further research with a greater sample size and statistical power is needed to explore this possibility. Future research could investigate which characteristics make this subject domain distinct, in which contexts within digital tooling this type of intervention is most effective and which benefits it should aim to provide.
...
This research conducted a quasi-experiment with 122 second-grade students from a Havo/Vwo high school during a course on Google Spreadsheets. The experimental group had access to a button that let the computer instantly check their homework and provide feedback, while the control group did not. At the end of the course, students in the experimental group completed a questionnaire to share their experiences.
This research found no significant effects of the intervention on behavioral student engagement and learning outcomes, nor was a mediated relationship established. However, students did report several cognitive and metacognitive benefits. Namely: enhanced motivation, enhanced self-regulated learning, enhanced autonomy, feedback that helped them move forward and an improved understanding of the material. On the other hand, they reported some downsides. Namely: increased time consumption, a lack of added value and a lack of feedback quality.
Since this research did not find effects of computer assisted formative assessment similar to those observed in other subject areas, it raises the question of whether the subject domain of digital tooling interacts differently with this type of intervention. Further research with a greater sample size and statistical power is needed to explore this possibility. Future research could investigate which characteristics make this subject domain distinct, in which contexts within digital tooling this type of intervention is most effective and which benefits it should aim to provide.
On the Effectiveness of Modeling Uncertain Constraint-Based Utility Functions with Quadratic Polynomials
With Applications in Autonomous Negotiations
The main contributions of this thesis are threefold. First, it introduces a probabilistic complexity measure for these hypercubic functions, capturing how parameters such as dimensionality, constraint width, the number of constraints, and the number of issues interact to shape the function's complexity. Second, it develops a novel agent that leverages a regression model with quadratic basis functions to construct a surrogate model of a hypercubic constraint-based utility function. Third, it evaluates the agent through extensive experiments, demonstrating how performance scales with complexity. Following the steps outlined in this thesis, the performance of surrogate models can be directly compared.
The results demonstrate that the surrogate-based method is a promising approach, as the agent constructed in this thesis outperforms the agents from the 2014 Automated Negotiating Agent Competition which used similar scenarios as those considered in this thesis. These agents all have in common that they directly search the utility function as opposed to a surrogate model of it. Furthermore, the results indicate that simple basis functions, such as quadratic ones, enable the agent to reach the global maximum of its utility function in low-complexity hypercubic cases, with performance scaling reasonably well up to medium complexity. Beyond this point, however, performance deteriorates rapidly, clearly signaling the need for more expressive surrogate models. ...
The main contributions of this thesis are threefold. First, it introduces a probabilistic complexity measure for these hypercubic functions, capturing how parameters such as dimensionality, constraint width, the number of constraints, and the number of issues interact to shape the function's complexity. Second, it develops a novel agent that leverages a regression model with quadratic basis functions to construct a surrogate model of a hypercubic constraint-based utility function. Third, it evaluates the agent through extensive experiments, demonstrating how performance scales with complexity. Following the steps outlined in this thesis, the performance of surrogate models can be directly compared.
The results demonstrate that the surrogate-based method is a promising approach, as the agent constructed in this thesis outperforms the agents from the 2014 Automated Negotiating Agent Competition which used similar scenarios as those considered in this thesis. These agents all have in common that they directly search the utility function as opposed to a surrogate model of it. Furthermore, the results indicate that simple basis functions, such as quadratic ones, enable the agent to reach the global maximum of its utility function in low-complexity hypercubic cases, with performance scaling reasonably well up to medium complexity. Beyond this point, however, performance deteriorates rapidly, clearly signaling the need for more expressive surrogate models.
Continual Learning for Embodied Agents: Methods, Evaluation and Practical Use
A Systematic Literature Review
Open-endedness and intrinsic motivation in embodied virtual agents
A Systematic Literature Review
Extending the Theory of Mind Framework to Embodied Artificial Agents
A Systematic Literature Review
Developing a monitoring process for IPC Acute Food Insecurity analyses
A case study on Human-Centered AI for humanitarian decision-making
Animating Still Images
Folding Texture Design and Synthesis
However, to date, no tool has been developed to assist in the design and synthesis of folding textures. Applications of the technique so far are achieved through manual creation of the folding texture, which is a tedious process.
This thesis explores the problem of folding-texture design and synthesis. A novel approach is proposed for animating still images based on the folding texture technique. The approach uses a semi-automatic, user-assisted method that combines texture editing, motion profile specification, and folding texture synthesis into one seamless process, reducing the need for extensive manual work. It enables novice users to utilize the technique with a fair level of prior knowledge of folding texture. ...
However, to date, no tool has been developed to assist in the design and synthesis of folding textures. Applications of the technique so far are achieved through manual creation of the folding texture, which is a tedious process.
This thesis explores the problem of folding-texture design and synthesis. A novel approach is proposed for animating still images based on the folding texture technique. The approach uses a semi-automatic, user-assisted method that combines texture editing, motion profile specification, and folding texture synthesis into one seamless process, reducing the need for extensive manual work. It enables novice users to utilize the technique with a fair level of prior knowledge of folding texture.
The Words are not Enough
An Investigation into the Viability of Textual Complexity as a Feature for Recommendation Systems
Immediate feedback is when the user fills in an answer and the system immediately provides information to strengthen knowledge.
When applied to an academic environment, both immediate feedback and student engagement have been proven to be important for completing a task.
Using a literature review, we found that immediate feedback can be directly linked to educational techniques such as self-improvement, self-efficacy, and the Self-Determination Theory. Through a focus group, we also found that constructive immediate feedback is an important pillar of De Kindertelefoon.
The design was achieved by looking at the existing and limited 5-phase model as a graph and trying to find an optimal path through that graph.
After conducting a within-subjects study experiment with 34 participants, the results were inconclusive, with neither condition appearing to be more useful for the group of participants, nor either condition being better at teaching them the 5-phase model.
As the results were inconclusive, the data was explored more by looking at it as a between-subject study, which showed that the explanation sheet might perform better for knowledge.
The research shows the possible strength of feedback in a practical manner. From the results, the immediate feedback is neither more nor less resonant than a classical approach to teaching the 5-phase model. ...
Immediate feedback is when the user fills in an answer and the system immediately provides information to strengthen knowledge.
When applied to an academic environment, both immediate feedback and student engagement have been proven to be important for completing a task.
Using a literature review, we found that immediate feedback can be directly linked to educational techniques such as self-improvement, self-efficacy, and the Self-Determination Theory. Through a focus group, we also found that constructive immediate feedback is an important pillar of De Kindertelefoon.
The design was achieved by looking at the existing and limited 5-phase model as a graph and trying to find an optimal path through that graph.
After conducting a within-subjects study experiment with 34 participants, the results were inconclusive, with neither condition appearing to be more useful for the group of participants, nor either condition being better at teaching them the 5-phase model.
As the results were inconclusive, the data was explored more by looking at it as a between-subject study, which showed that the explanation sheet might perform better for knowledge.
The research shows the possible strength of feedback in a practical manner. From the results, the immediate feedback is neither more nor less resonant than a classical approach to teaching the 5-phase model.