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Contrasting Global and Patient-Specific Regression Models via a Neural Network Representation

Behrens, Max, Stolz, Daiana, Papakonstantinou, Eleni, Nolde, Janis M., Bellerino, Gabriele, Rohde, Angelika, Hess, Moritz, Binder, Harald

arXiv.org Machine Learning

When developing clinical prediction models, it can be challenging to balance between global models that are valid for all patients and personalized models tailored to individuals or potentially unknown subgroups. To aid such decisions, we propose a diagnostic tool for contrasting global regression models and patient-specific (local) regression models. The core utility of this tool is to identify where and for whom a global model may be inadequate. We focus on regression models and specifically suggest a localized regression approach that identifies regions in the predictor space where patients are not well represented by the global model. As localization becomes challenging when dealing with many predictors, we propose modeling in a dimension-reduced latent representation obtained from an autoencoder. Using such a neural network architecture for dimension reduction enables learning a latent representation simultaneously optimized for both good data reconstruction and for revealing local outcome-related associations suitable for robust localized regression. We illustrate the proposed approach with a clinical study involving patients with chronic obstructive pulmonary disease. Our findings indicate that the global model is adequate for most patients but that indeed specific subgroups benefit from personalized models. We also demonstrate how to map these subgroup models back to the original predictors, providing insight into why the global model falls short for these groups. Thus, the principal application and diagnostic yield of our tool is the identification and characterization of patients or subgroups whose outcome associations deviate from the global model. Introduction In clinical research, conclusions about potential relationships between patient characteristics and outcomes often are based on regression models. More specifically, there might not be just some random variability across the parameters of patients, e.g. as considered in regression modeling with random effects (Pinheiro and Bates, 2000), but different regions in the space spanned by the patient characteristics might require different parameters. For example, the relation of some patient characteristics to the outcome might be more pronounced for older patients with high body weight, without having a corresponding pre-defined subgroup indicator. While sticking to a global model keeps interpretation simple and is beneficial in terms of statistical stability, it would at least be useful to have some diagnostic tool for judging the potential extent of deviations from the global model.


Computer Vision for Real-Time Monkeypox Diagnosis on Embedded Systems

Delgado-López, Jacob M., Morell-Rodriguez, Ricardo A., Rosario, Sebastián O. Espinosa-Del, Lugo-Beauchamp, Wilfredo E.

arXiv.org Artificial Intelligence

The rapid diagnosis of infectious diseases, such as monkeypox, is crucial for effective containment and treatment, particularly in resource-constrained environments. This study presents an AI-driven diagnostic tool developed for deployment on the NVIDIA Jetson Orin Nano, leveraging the pre-trained MobileNetV2 architecture for binary classification. The model was trained on the open-source Monkeypox Skin Lesion Dataset, achieving a 93.07% F1-Score, which reflects a well-balanced performance in precision and recall. To optimize the model, the TensorRT framework was used to accelerate inference for FP32 and to perform post-training quantization for FP16 and INT8 formats. TensorRT's mixed-precision capabilities enabled these optimizations, which reduced the model size, increased inference speed, and lowered power consumption by approximately a factor of two, all while maintaining the original accuracy. Power consumption analysis confirmed that the optimized models used significantly less energy during inference, reinforcing their suitability for deployment in resource-constrained environments. The system was deployed with a Wi-Fi Access Point (AP) hotspot and a web-based interface, enabling users to upload and analyze images directly through connected devices such as mobile phones. This setup ensures simple access and seamless connectivity, making the tool practical for real-world applications. These advancements position the diagnostic tool as an efficient, scalable, and energy-conscious solution to address diagnosis challenges in underserved regions, paving the way for broader adoption in low-resource healthcare settings.


Pass@k Metric for RLVR: A Diagnostic Tool of Exploration, But Not an Objective

Yu, Yang

arXiv.org Artificial Intelligence

The ability of Large Language Models (LLMs) to perform complex, multi-step reasoning is a central focus of modern AI research. To evaluate and enhance this capability, the pass@k metric, which measures the probability of obtaining at least one correct solution in k independent samples, has received significant attention. Its intuitive appeal has led to its adoption not only as an evaluation standard but also as a direct optimization objective in reinforcement learning. In this paper, we analyze the pass@k objective, derive its gradient, and demonstrate that it is fundamentally a per-example positive reweighting of the simpler pass@1 objective. Our analysis reveals that the pass@k objective provides a vanishing learning signal in regimes where exploration is most critical. We further analyze the dynamics of "exploration collapse", showing that as the policy concentrates probability mass, the gap between pass@k and pass@1 diminishes. We conclude that while pass@k is a useful diagnostic tool, it may be an unsuitable direct objective for optimization. Instead, mechanisms explicitly encouraging efficient exploration could offer a more effective path forward for reinforcement learning in reasoning tasks.


Bag of Coins: A Statistical Probe into Neural Confidence Structures

Aich, Agnideep, Aich, Ashit Baran, Murshed, Md Monzur, Hewage, Sameera, Wade, Bruce

arXiv.org Machine Learning

Modern neural networks, despite their high accuracy, often produce poorly calibrated confidence scores, limiting their reliability in high-stakes applications. Existing calibration methods typically post-process model outputs without interrogating the internal consistency of the predictions themselves. In this work, we introduce a novel, non-parametric statistical probe, the Bag-of-Coins (BoC) test, that examines the internal consistency of a classifier's logits. The BoC test reframes confidence estimation as a frequentist hypothesis test: does the model's top-ranked class win 1-v-1 contests against random competitors at a rate consistent with its own stated softmax probability? When applied to modern deep learning architectures, this simple probe reveals a fundamental dichotomy. On Vision Transformers (ViTs), the BoC output serves as a state-of-the-art confidence score, achieving near-perfect calibration with an ECE of 0.0212, an 88% improvement over a temperature-scaled baseline. Conversely, on Convolutional Neural Networks (CNNs) like ResNet, the probe reveals a deep inconsistency between the model's predictions and its internal logit structure, a property missed by traditional metrics. We posit that BoC is not merely a calibration method, but a new diagnostic tool for understanding and exposing the differing ways that popular architectures represent uncertainty.


Multimodal Lead-Specific Modeling of ECG for Low-Cost Pulmonary Hypertension Assessment

Suvon, Mohammod N. I., Zhou, Shuo, Tripathi, Prasun C., Fan, Wenrui, Alabed, Samer, Khanal, Bishesh, Osmani, Venet, Swift, Andrew J., Chen, null, Chen, null, Lu, Haiping

arXiv.org Artificial Intelligence

Pulmonary hypertension (PH) is frequently underdiagnosed in low- and middle-income countries (LMICs) primarily due to the scarcity of advanced diagnostic tools. Several studies in PH have applied machine learning to low-cost diagnostic tools like 12-lead ECG (12L-ECG), but they mainly focus on areas with limited resources, overlooking areas with no diagnostic tools, such as rural primary healthcare in LMICs. Recent studies have shown the effectiveness of 6-lead ECG (6L-ECG), as a cheaper and portable alternative in detecting various cardiac conditions, but its clinical value for PH detection is not well proved. Furthermore, existing methods treat 12L-/6L-ECG as a single modality, capturing only shared features while overlooking lead-specific features essential for identifying complex cardiac hemodynamic changes. In this paper, we propose Lead-Specific Electrocardiogram Multimodal Variational Autoencoder (LS-EMVAE), a model pre-trained on large-population 12L-ECG data and fine-tuned on task-specific data (12L-ECG or 6L-ECG). LS-EMVAE models each 12L-ECG lead as a separate modality and introduces a hierarchical expert composition using Mixture and Product of Experts for adaptive latent feature fusion between lead-specific and shared features. Unlike existing approaches, LS-EMVAE makes better predictions on both 12L-ECG and 6L-ECG at inference, making it an equitable solution for areas with limited or no diagnostic tools. We pre-trained LS-EMVAE on 800,000 publicly available 12L-ECG samples and fine-tuned it for two tasks: 1) PH detection and 2) phenotyping pre-/post-capillary PH, on in-house datasets of 892 and 691 subjects across 12L-ECG and 6L-ECG settings. Extensive experiments show that LS-EMVAE outperforms existing baselines in both ECG settings, while 6L-ECG achieves performance comparable to 12L-ECG, unlocking its potential for global PH screening in areas without diagnostic tools.


Charlotte Bunne on developing AI-based diagnostic tools

AIHub

Charlotte Bunne, head of EPFL's Artificial Intelligence in Molecular Medicine Group, is developing AI algorithms to better understand the incredibly complex and high-dimensional data that represent the hundreds of tissue layers and protein markers in an individual cell. EPFL magazine Dimensions spoke to Charlotte Bunne about her work at the cutting-edge of AI in medicine and biology. Could you describe the focus of your research? We are developing diagnostic tools for clinics that are driven by AI technologies. This includes forecasting the best treatment that a patient should receive, trying to understand the state of disease that a patient is in, and deciphering important biomarkers or potential drug targets that we should investigate further.


Towards Equitable ASD Diagnostics: A Comparative Study of Machine and Deep Learning Models Using Behavioral and Facial Data

Aledhari, Mohammed, Rahouti, Mohamed, Alfatemi, Ali

arXiv.org Artificial Intelligence

Abstract--Autism Spectrum Disorder (ASD) is often underdiagnosed in females due to gender-specific symptom differences overlooked by conventional diagnostics. This study evaluates machine learning models, particularly Random Forest and convolutional neural networks, for enhancing ASD diagnosis through structured data and facial image analysis. Random Forest achieved 100% validation accuracy across datasets, highlighting its ability to manage complex relationships and reduce false negatives, which is crucial for early intervention and addressing gender biases. In image-based analysis, MobileNet outperformed the baseline CNN, achieving 87% accuracy, though a 30% validation loss suggests possible overfitting, requiring further optimization for robustness in clinical settings. Future work will emphasize hyperparameter tuning, regularization, and transfer learning. Integrating behavioral data with facial analysis could improve diagnosis for underdiagnosed groups. These findings suggest Random Forest's high accuracy and balanced precision-recall metrics could enhance clinical workflows. MobileNet's lightweight structure also shows promise for resource-limited environments, enabling accessible ASD screening. Addressing model explainability and clinician trust will be vital.


How you may soon be able to hold hands with a loved one who lives thousands of miles away - through a new soft fingertip device

Daily Mail - Science & tech

Long-distance friendships and relationships can be hard at the best of times. But new technology might soon let you hold hands with a loved one from thousands of miles away. Experts have designed a soft fingertip device that enables the realistic feeling of touch - one of the most complex sensations in the human body. The bioinspired haptic (BAMH) system works by simulating all four touch receptors in the human finger using vibrations at different speeds and strengths across multiple areas. The team behind the device said they believe they have the technology to create a glove, which could eventually enable remote social interaction and the feeling of holding a hand.


Apple's self-repair program now includes the iPhone 15 and more M2-powered Macs

Engadget

Apple has announced a major expansion of its self-repair program, as the company will now allow iPhone 15 and M2-powered Mac users to fix their own devices. This comes after the tech company opened up the program to include iPhone 14 models and M2-powered laptops earlier this year. The devices added to the DIY repair roster include the entire iPhone 15 lineup, the Mac Pro, Mac Studio, the 16-inch MacBook Pro and the 15-inch MacBook Air, among others. There's also a brand-new diagnostic tool to help users to get to the bottom of things. Apple already offered a System Configuration tool that came up when the device was in Diagnostics mode, but this goes several steps further.


AI-powered mental health diagnostic tool could be the first of its kind to predict, treat depression

FOX News

Fox News correspondent Grady Trimble has the latest on fears the technology will spiral out of control on'Special Report.' As the world of artificial intelligence blooms, some players in the health care industry are looking to make a major difference in public health. HMNC Brain Health -- a Munich, Germany-based health tech company -- is one of those. It's attempting to use novel AI-powered technologies to address mental health issues. The company has developed what's described as a "precision psychiatry" diagnostic tool that uses artificial intelligence to predict, diagnose and even treat depression.