Natick
- Information Technology (1.00)
- Health & Medicine (1.00)
- Law (0.93)
- (2 more...)
- North America > Canada > Ontario > Toronto (0.14)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.14)
- North America > United States > Illinois > Cook County > Chicago (0.04)
- (3 more...)
- Information Technology > Artificial Intelligence > Representation & Reasoning (1.00)
- Information Technology > Artificial Intelligence > Cognitive Science (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (0.93)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning (0.67)
- North America > United States > Massachusetts > Middlesex County > Natick (0.04)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
Detecting Batch Heterogeneity via Likelihood Clustering
Batch effects represent a major confounder in genomic diagnostics. In copy number variant (CNV) detection from NGS, many algorithms compare read depth between test samples and a reference sample, assuming they are process-matched. When this assumption is violated, with causes ranging from reagent lot changes to multi-site processing, the reference becomes inappropriate, introducing false CNV calls or masking true pathogenic variants. Detecting such heterogeneity before downstream analysis is critical for reliable clinical interpretation. Existing batch effect detection methods either cluster samples based on raw features, risking conflation of biological signal with technical variation, or require known batch labels that are frequently unavailable. We introduce a method that addresses both limitations by clustering samples according to their Bayesian model evidence. The central insight is that evidence quantifies compatibility between data and model assumptions, technical artifacts violate assumptions and reduce evidence, whereas biological variation, including CNV status, is anticipated by the model and yields high evidence. This asymmetry provides a discriminative signal that separates batch effects from biology. We formalize heterogeneity detection as a likelihood ratio test for mixture structure in evidence space, using parametric bootstrap calibration to ensure conservative false positive rates. We validate our approach on synthetic data demonstrating proper Type I error control, three clinical targeted sequencing panels (liquid biopsy, BRCA, and thalassemia) exhibiting distinct batch effect mechanisms, and mouse electrophysiology recordings demonstrating cross-modality generalization. Our method achieves superior clustering accuracy compared to standard correlation-based and dimensionality-reduction approaches while maintaining the conservativeness required for clinical usage.
- North America > United States > Massachusetts > Middlesex County > Natick (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Research Report > Experimental Study (0.70)
- Research Report > New Finding (0.46)
Constraint- and Score-Based Nonlinear Granger Causality Discovery with Kernels
Murphy, Fiona, Benavoli, Alessio
Granger causality (GC) [15] is a time series causal discovery framework that uses predictive modeling to identify the underlying causal structure of a time series system. Relying on the assumption that cause precedes effect, GC assesses whether including the lagged information from one time series in the autoregressive model of a second time series enhances its predictions. This improvement indicates a predictive relationship between the time series variables, where one time series provides supplemental information about the future of another time series, thereby signifying the presence of a (Granger) causal relationship. GC requires only observational data, and has been used for time series causal discovery across diverse domains, including climate science [33], political and social sciences [17], econometrics [4], and biological systems studies [13]. The original formulation of GC requires several assumptions to be satisfied for causal identifiability. In regards to the candidate time series system, it is assumed that the time series variables are stationary, and that all variables are observed (absence of latent confounders). GC was initially proposed for bivariate time series systems, but was generalised for the multivariate setting to accommodate the assumption that all relevant variables are included in the analysis [15]. Additional assumptions are made with regard to the types of causal relationships that can be identified within the time series system. GC cannot estimate a causal relationship between time series at an instantaneous time point, relying on the relationship between the lags and predicted values to determine a GC relationship.
- Europe > Ireland > Leinster > County Dublin > Dublin (0.14)
- North America > United States > Massachusetts > Middlesex County > Cambridge (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- (5 more...)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Uncertainty (0.94)
- Information Technology > Artificial Intelligence > Machine Learning > Performance Analysis > Accuracy (0.93)
Control of Powered Ankle-Foot Prostheses on Compliant Terrain: A Quantitative Approach to Stability Enhancement
Karakasis, Chrysostomos, Scully, Camryn, Salati, Robert, Artemiadis, Panagiotis
Walking on compliant terrain presents a substantial challenge for individuals with lower-limb amputation, further elevating their already high risk of falling. While powered ankle-foot prostheses have demonstrated adaptability across speeds and rigid terrains, control strategies optimized for soft or compliant surfaces remain underexplored. This work experimentally validates an admittance-based control strategy that dynamically adjusts the quasi-stiffness of powered prostheses to enhance gait stability on compliant ground. Human subject experiments were conducted with three healthy individuals walking on two bilaterally compliant surfaces with ground stiffness values of 63 and 25 kN/m, representative of real-world soft environments. Controller performance was quantified using phase portraits and two walking stability metrics, offering a direct assessment of fall risk. Compared to a standard phase-variable controller developed for rigid terrain, the proposed admittance controller consistently improved gait stability across all compliant conditions. These results demonstrate the potential of adaptive, stability-aware prosthesis control to reduce fall risk in real-world environments and advance the robustness of human-prosthesis interaction in rehabilitation robotics.
- North America > United States > Delaware > New Castle County > Newark (0.14)
- North America > United States > Texas > Harris County > Houston (0.04)
- North America > United States > Massachusetts > Suffolk County > South Boston (0.04)
- (3 more...)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
- Health & Medicine > Health Care Technology (1.00)
- Health & Medicine > Therapeutic Area > Orthopedics/Orthopedic Surgery (0.46)
- Health & Medicine > Therapeutic Area > Neurology (0.46)
Resource-Efficient Beam Prediction in mmWave Communications with Multimodal Realistic Simulation Framework
Park, Yu Min, Tun, Yan Kyaw, Huh, Eui-Nam, Saad, Walid, Hong, Choong Seon
Beamforming is a key technology in millimeter-wave (mmWave) communications that improves signal transmission by optimizing directionality and intensity. However, conventional channel estimation methods, such as pilot signals or beam sweeping, often fail to adapt to rapidly changing communication environments. To address this limitation, multimodal sensing-aided beam prediction has gained significant attention, using various sensing data from devices such as LiDAR, radar, GPS, and RGB images to predict user locations or network conditions. Despite its promising potential, the adoption of multimodal sensing-aided beam prediction is hindered by high computational complexity, high costs, and limited datasets. Thus, in this paper, a novel resource-efficient learning framework is introduced for beam prediction, which leverages a custom-designed cross-modal relational knowledge distillation (CRKD) algorithm specifically tailored for beam prediction tasks, to transfer knowledge from a multimodal network to a radar-only student model, achieving high accuracy with reduced computational cost. To enable multimodal learning with realistic data, a novel multimodal simulation framework is developed while integrating sensor data generated from the autonomous driving simulator CARLA with MATLAB-based mmWave channel modeling, and reflecting real-world conditions. The proposed CRKD achieves its objective by distilling relational information across different feature spaces, which enhances beam prediction performance without relying on expensive sensor data. Simulation results demonstrate that CRKD efficiently distills multimodal knowledge, allowing a radar-only model to achieve $94.62%$ of the teacher performance. In particular, this is achieved with just $10%$ of the teacher network's parameters, thereby significantly reducing computational complexity and dependence on multimodal sensor data.
- North America > United States > Virginia (0.04)
- North America > United States > Massachusetts > Middlesex County > Natick (0.04)
- North America > United States > California > San Diego County > San Diego (0.04)
- (3 more...)
- Education (0.67)
- Information Technology (0.66)
- Transportation > Ground > Road (0.48)
Adaptive Plane Reformatting for 4D Flow MRI using Deep Reinforcement Learning
Bisbal, Javier, Sotelo, Julio, Valdés, Maria I, Irarrazaval, Pablo, Andia, Marcelo E, García, Julio, Rodriguez-Palomarez, José, Raimondi, Francesca, Tejos, Cristián, Uribe, Sergio
Background and Objective: Plane reformatting for four-dimensional phase contrast MRI (4D flow MRI) is time-consuming and prone to inter-observer variability, which limits fast cardiovascular flow assessment. Deep reinforcement learning (DRL) trains agents to iteratively adjust plane position and orientation, enabling accurate plane reformatting without the need for detailed landmarks, making it suitable for images with limited contrast and resolution such as 4D flow MRI. However, current DRL methods assume that test volumes share the same spatial alignment as the training data, limiting generalization across scanners and institutions. To address this limitation, we introduce AdaPR (Adaptive Plane Reformatting), a DRL framework that uses a local coordinate system to navigate volumes with arbitrary positions and orientations. Methods: We implemented AdaPR using the Asynchronous Advantage Actor-Critic (A3C) algorithm and validated it on 88 4D flow MRI datasets acquired from multiple vendors, including patients with congenital heart disease. Results: AdaPR achieved a mean angular error of 6.32 +/- 4.15 degrees and a distance error of 3.40 +/- 2.75 mm, outperforming global-coordinate DRL methods and alternative non-DRL methods. AdaPR maintained consistent accuracy under different volume orientations and positions. Flow measurements from AdaPR planes showed no significant differences compared to two manual observers, with excellent correlation (R^2 = 0.972 and R^2 = 0.968), comparable to inter-observer agreement (R^2 = 0.969). Conclusion: AdaPR provides robust, orientation-independent plane reformatting for 4D flow MRI, achieving flow quantification comparable to expert observers. Its adaptability across datasets and scanners makes it a promising candidate for medical imaging applications beyond 4D flow MRI.
- North America > Canada > Alberta > Census Division No. 6 > Calgary Metropolitan Region > Calgary (0.14)
- North America > United States > California > San Francisco County > San Francisco (0.14)
- South America > Chile > Santiago Metropolitan Region > Santiago Province > Santiago (0.05)
- (13 more...)
- Research Report > New Finding (1.00)
- Research Report > Experimental Study (1.00)
- Health & Medicine > Therapeutic Area > Cardiology/Vascular Diseases (1.00)
- Health & Medicine > Diagnostic Medicine > Imaging (1.00)
Probabilistic Digital Twin for Misspecified Structural Dynamical Systems via Latent Force Modeling and Bayesian Neural Networks
This work presents a probabilistic digital twin framework for response prediction in dynamical systems governed by misspecified physics. The approach integrates Gaussian Process Latent Force Models (GPLFM) and Bayesian Neural Networks (BNNs) to enable end-to-end uncertainty-aware inference and prediction. In the diagnosis phase, model-form errors (MFEs) are treated as latent input forces to a nominal linear dynamical system and jointly estimated with system states using GPLFM from sensor measurements. A BNN is then trained on posterior samples to learn a probabilistic nonlinear mapping from system states to MFEs, while capturing diagnostic uncertainty. For prognosis, this mapping is used to generate pseudo-measurements, enabling state prediction via Kalman filtering. The framework allows for systematic propagation of uncertainty from diagnosis to prediction, a key capability for trustworthy digital twins. The framework is demonstrated using four nonlinear examples: a single degree of freedom (DOF) oscillator, a multi-DOF system, and two established benchmarks -- the Bouc-Wen hysteretic system and the Silverbox experimental dataset -- highlighting its predictive accuracy and robustness to model misspecification.
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- North America > United States > New Mexico > Bernalillo County > Albuquerque (0.04)
- North America > United States > Massachusetts > Middlesex County > Natick (0.04)
- (5 more...)
Modeling Retinal Ganglion Cells with Neural Differential Equations
Dobek, Kacper, Jankowski, Daniel, Krawiec, Krzysztof
This work explores Liquid Time-Constant Networks (LTCs) and Closed-form Continuous-time Networks (CfCs) for modeling retinal ganglion cell activity in tiger salamanders across three datasets. Compared to a convolutional baseline and an LSTM, both architectures achieved lower MAE, faster convergence, smaller model sizes, and favorable query times, though with slightly lower Pearson correlation. Their efficiency and adaptability make them well suited for scenarios with limited data and frequent retraining, such as edge deployments in vision prosthetics.
- Europe > Poland > Greater Poland Province > Poznań (0.05)
- North America > United States > Massachusetts > Middlesex County > Natick (0.04)
- North America > United States > California > Santa Clara County > Palo Alto (0.04)