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Publications
Spinal cord evaluation in multiple sclerosis: clinical and radiological associations, present and future
Abstract Spinal cord disease is important in most people with multiple sclerosis, but assessment remains less emphasized in patient care, ba… (see more)sic and clinical research and therapeutic trials. The North American Imaging in Multiple Sclerosis Spinal Cord Interest Group was formed to determine and present the contemporary landscape of multiple sclerosis spinal cord evaluation, further existing and advanced spinal cord imaging techniques, and foster collaborative work. Important themes arose: (i) multiple sclerosis spinal cord lesions (differential diagnosis, association with clinical course); (ii) spinal cord radiological–pathological associations; (iii) ‘critical’ spinal cord lesions; (iv) multiple sclerosis topographical model; (v) spinal cord atrophy; and (vi) automated and special imaging techniques. Distinguishing multiple sclerosis from other myelopathic aetiology is increasingly refined by imaging and serological studies. Post-mortem spinal cord findings and MRI pathological correlative studies demonstrate MRI’s high sensitivity in detecting microstructural demyelination and axonal loss. Spinal leptomeninges include immune inflammatory infiltrates, some in B-cell lymphoid-like structures. ‘Critical’ demyelinating lesions along spinal cord corticospinal tracts are anatomically consistent with and may be disproportionately associated with motor progression. Multiple sclerosis topographical model implicates the spinal cord as an area where threshold impairment associates with multiple sclerosis disability. Progressive spinal cord atrophy and ‘silent’ multiple sclerosis progression may be emerging as an important multiple sclerosis prognostic biomarker. Manual atrophy assessment is complicated by rater bias, while automation (e.g. Spinal Cord Toolbox), and artificial intelligence may reduce this. Collaborative research by the North American Imaging in Multiple Sclerosis and similar groups with experts combining distinct strengths is key to advancing assessment and treatment of people with multiple sclerosis spinal cord disease.
Text-to-SQL enables users to interact with databases through natural language, simplifying access to structured data. Although highly capabl… (see more)e large language models (LLMs) achieve strong accuracy for complex queries, they incur unnecessary latency and dollar cost for simpler ones. In this paper, we introduce the first LLM routing approach for Text-to-SQL, which dynamically selects the most cost-effective LLM capable of generating accurate SQL for each query. We present two routing strategies (score- and classification-based) that achieve accuracy comparable to the most capable LLM while reducing costs. We design the routers for ease of training and efficient inference. In our experiments, we highlight a practical and explainable accuracy-cost trade-off on the BIRD dataset.
Text-to-SQL enables users to interact with databases through natural language, simplifying access to structured data. Although highly capabl… (see more)e large language models (LLMs) achieve strong accuracy for complex queries, they incur unnecessary latency and dollar cost for simpler ones. In this paper, we introduce the first LLM routing approach for Text-to-SQL, which dynamically selects the most cost-effective LLM capable of generating accurate SQL for each query. We present two routing strategies (score- and classification-based) that achieve accuracy comparable to the most capable LLM while reducing costs. We design the routers for ease of training and efficient inference. In our experiments, we highlight a practical and explainable accuracy-cost trade-off on the BIRD dataset.
Large-scale training of latent diffusion models (LDMs) has enabled unprecedented quality in image generation. However, the key components of… (see more) the best performing LDM training recipes are oftentimes not available to the research community, preventing apple-to-apple comparisons and hindering the validation of progress in the field. In this work, we perform an in-depth study of LDM training recipes focusing on the performance of models and their training efficiency. To ensure apple-to-apple comparisons, we re-implement five previously published models with their corresponding recipes. Through our study, we explore the effects of (i)~the mechanisms used to condition the generative model on semantic information (e.g., text prompt) and control metadata (e.g., crop size, random flip flag, etc.) on the model performance, and (ii)~the transfer of the representations learned on smaller and lower-resolution datasets to larger ones on the training efficiency and model performance. We then propose a novel conditioning mechanism that disentangles semantic and control metadata conditionings and sets a new state-of-the-art in class-conditional generation on the ImageNet-1k dataset -- with FID improvements of 7% on 256 and 8% on 512 resolutions -- as well as text-to-image generation on the CC12M dataset -- with FID improvements of 8% on 256 and 23% on 512 resolution.
High-level synthesis (HLS) produces hardware au-tomatically by scheduling and assigning resources based on an input control/data-flow graph.… (see more) One particular aspect of HLS for the digital signal processing (DSP) architecture is the het-erogeneous assignment problem (HAP) which maps operations into different types of functional units available in the electronic design automation tools to build efficient implementations. An optimal solution to this assignment problem can be found by formulating the problem as integer linear programming (ILP) and using a solver. However, given the slow nature of this process, heuristics tend to be used instead leading to sub-optimal designs. This paper revisits the classical ILP formulation of the HAP with time constraints for the DSP architecture by identifying redundant constraints. This paper proves theoretically, and demonstrates experimentally, that removing these constraints does not affect the obtained solution. This technique achieves speedups of more than 100 × in terms of runtime and reductions of more than 50 × in terms of memory usage of the solver. Also, this work proposes an updated heuristic that keeps reducing the latency of a path instead of finding a new critical path after giving a new node assignment. Runtime reductions (more than another 10×) due to reduced numbers of critical path searches are observed while returning similar results.
2024-11-04
IEEE Workshop on Signal Processing Systems (published)
High-level synthesis (HLS) produces hardware au-tomatically by scheduling and assigning resources based on an input control/data-flow graph.… (see more) One particular aspect of HLS for the digital signal processing (DSP) architecture is the het-erogeneous assignment problem (HAP) which maps operations into different types of functional units available in the electronic design automation tools to build efficient implementations. An optimal solution to this assignment problem can be found by formulating the problem as integer linear programming (ILP) and using a solver. However, given the slow nature of this process, heuristics tend to be used instead leading to sub-optimal designs. This paper revisits the classical ILP formulation of the HAP with time constraints for the DSP architecture by identifying redundant constraints. This paper proves theoretically, and demonstrates experimentally, that removing these constraints does not affect the obtained solution. This technique achieves speedups of more than 100 × in terms of runtime and reductions of more than 50 × in terms of memory usage of the solver. Also, this work proposes an updated heuristic that keeps reducing the latency of a path instead of finding a new critical path after giving a new node assignment. Runtime reductions (more than another 10×) due to reduced numbers of critical path searches are observed while returning similar results.
2024-11-04
IEEE Workshop on Signal Processing Systems (published)
High-level synthesis (HLS) produces hardware au-tomatically by scheduling and assigning resources based on an input control/data-flow graph.… (see more) One particular aspect of HLS for the digital signal processing (DSP) architecture is the het-erogeneous assignment problem (HAP) which maps operations into different types of functional units available in the electronic design automation tools to build efficient implementations. An optimal solution to this assignment problem can be found by formulating the problem as integer linear programming (ILP) and using a solver. However, given the slow nature of this process, heuristics tend to be used instead leading to sub-optimal designs. This paper revisits the classical ILP formulation of the HAP with time constraints for the DSP architecture by identifying redundant constraints. This paper proves theoretically, and demonstrates experimentally, that removing these constraints does not affect the obtained solution. This technique achieves speedups of more than 100 × in terms of runtime and reductions of more than 50 × in terms of memory usage of the solver. Also, this work proposes an updated heuristic that keeps reducing the latency of a path instead of finding a new critical path after giving a new node assignment. Runtime reductions (more than another 10×) due to reduced numbers of critical path searches are observed while returning similar results.
2024-11-04
IEEE Workshop on Signal Processing Systems (published)
High-level synthesis (HLS) produces hardware au-tomatically by scheduling and assigning resources based on an input control/data-flow graph.… (see more) One particular aspect of HLS for the digital signal processing (DSP) architecture is the het-erogeneous assignment problem (HAP) which maps operations into different types of functional units available in the electronic design automation tools to build efficient implementations. An optimal solution to this assignment problem can be found by formulating the problem as integer linear programming (ILP) and using a solver. However, given the slow nature of this process, heuristics tend to be used instead leading to sub-optimal designs. This paper revisits the classical ILP formulation of the HAP with time constraints for the DSP architecture by identifying redundant constraints. This paper proves theoretically, and demonstrates experimentally, that removing these constraints does not affect the obtained solution. This technique achieves speedups of more than 100 × in terms of runtime and reductions of more than 50 × in terms of memory usage of the solver. Also, this work proposes an updated heuristic that keeps reducing the latency of a path instead of finding a new critical path after giving a new node assignment. Runtime reductions (more than another 10×) due to reduced numbers of critical path searches are observed while returning similar results.
2024-11-04
IEEE Workshop on Signal Processing Systems (published)
Working memory is a central cognitive ability crucial for intelligent decision-making. Recent experimental and computational work studying w… (see more)orking memory has primarily used categorical (i.e., one-hot) inputs, rather than ecologically relevant, multidimensional naturalistic ones. Moreover, studies have primarily investigated working memory during single or few cognitive tasks. As a result, an understanding of how naturalistic object information is maintained in working memory in neural networks is still lacking. To bridge this gap, we developed sensory-cognitive models, comprising a convolutional neural network (CNN) coupled with a recurrent neural network (RNN), and trained them on nine distinct N-back tasks using naturalistic stimuli. By examining the RNN's latent space, we found that: (1) Multi-task RNNs represent both task-relevant and irrelevant information simultaneously while performing tasks; (2) The latent subspaces used to maintain specific object properties in vanilla RNNs are largely shared across tasks, but highly task-specific in gated RNNs such as GRU and LSTM; (3) Surprisingly, RNNs embed objects in new representational spaces in which individual object features are less orthogonalized relative to the perceptual space; (4) The transformation of working memory encodings (i.e., embedding of visual inputs in the RNN latent space) into memory was shared across stimuli, yet the transformations governing the retention of a memory in the face of incoming distractor stimuli were distinct across time. Our findings indicate that goal-driven RNNs employ chronological memory subspaces to track information over short time spans, enabling testable predictions with neural data.
Recent advances in artificial intelligence (AI) have produced systems capable of increasingly sophisticated performance on cognitive tasks. … (see more)However, AI systems still struggle in critical ways: unpredictable and novel environments (robustness), lack of transparency in their reasoning (explainability), challenges in communication and commitment (cooperation), and risks due to potential harmful actions (safety). We argue that these shortcomings stem from one overarching failure: AI systems lack wisdom. Drawing from cognitive and social sciences, we define wisdom as the ability to navigate intractable problems - those that are ambiguous, radically uncertain, novel, chaotic, or computationally explosive - through effective task-level and metacognitive strategies. While AI research has focused on task-level strategies, metacognition - the ability to reflect on and regulate one's thought processes - is underdeveloped in AI systems. In humans, metacognitive strategies such as recognizing the limits of one's knowledge, considering diverse perspectives, and adapting to context are essential for wise decision-making. We propose that integrating metacognitive capabilities into AI systems is crucial for enhancing their robustness, explainability, cooperation, and safety. By focusing on developing wise AI, we suggest an alternative to aligning AI with specific human values - a task fraught with conceptual and practical difficulties. Instead, wise AI systems can thoughtfully navigate complex situations, account for diverse human values, and avoid harmful actions. We discuss potential approaches to building wise AI, including benchmarking metacognitive abilities and training AI systems to employ wise reasoning. Prioritizing metacognition in AI research will lead to systems that act not only intelligently but also wisely in complex, real-world situations.
Recent advances in artificial intelligence (AI) have produced systems capable of increasingly sophisticated performance on cognitive tasks. … (see more)However, AI systems still struggle in critical ways: unpredictable and novel environments (robustness), lack of transparency in their reasoning (explainability), challenges in communication and commitment (cooperation), and risks due to potential harmful actions (safety). We argue that these shortcomings stem from one overarching failure: AI systems lack wisdom. Drawing from cognitive and social sciences, we define wisdom as the ability to navigate intractable problems - those that are ambiguous, radically uncertain, novel, chaotic, or computationally explosive - through effective task-level and metacognitive strategies. While AI research has focused on task-level strategies, metacognition - the ability to reflect on and regulate one's thought processes - is underdeveloped in AI systems. In humans, metacognitive strategies such as recognizing the limits of one's knowledge, considering diverse perspectives, and adapting to context are essential for wise decision-making. We propose that integrating metacognitive capabilities into AI systems is crucial for enhancing their robustness, explainability, cooperation, and safety. By focusing on developing wise AI, we suggest an alternative to aligning AI with specific human values - a task fraught with conceptual and practical difficulties. Instead, wise AI systems can thoughtfully navigate complex situations, account for diverse human values, and avoid harmful actions. We discuss potential approaches to building wise AI, including benchmarking metacognitive abilities and training AI systems to employ wise reasoning. Prioritizing metacognition in AI research will lead to systems that act not only intelligently but also wisely in complex, real-world situations.
