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The extreme sport of skijoring, where horses pull skiers at 40 mph

Popular Science

Participants take part in a skijoring race in Zab, Poland, on January 25, 2026. Breakthroughs, discoveries, and DIY tips sent six days a week. The high-adrenaline winter sport of skijoring, derived from the Norwegian word for "ski driving," takes so many forms that it even defies uniform pronunciation. "If you go to France, it's skijoering, pronounced SKEE-zhor-ing. In German, it's skijöring, pronounced SHEE-yuh-ring," says Loren Zhimanskova, founder of Skijor International and Skijor USA.


Leveraging an ECG Beat Diffusion Model for Morphological Reconstruction from Indirect Signals

Neural Information Processing Systems

Electrocardiogram (ECG) signals provide essential information about the heart's condition and are widely used for diagnosing cardiovascular diseases. The morphology of a single heartbeat over the available leads is a primary biosignal for monitoring cardiac conditions. However, analyzing heartbeat morphology can be challenging due to noise and artifacts, missing leads, and a lack of annotated data.Generative models, such as denoising diffusion generative models (DDMs), have proven successful in generating complex data. We introduce $\texttt{BeatDiff}$, a light-weight DDM tailored for the morphology of multiple leads heartbeats.We then show that many important ECG downstream tasks can be formulated as conditional generation methods in a Bayesian inverse problem framework using $\texttt{BeatDiff}$ as priors. We propose $\texttt{EM-BeatDiff}$, an Expectation-Maximization algorithm, to solve this conditional generation tasks without fine-tuning. We illustrate our results with several tasks, such as removal of ECG noise and artifacts (baseline wander, electrode motion), reconstruction of a 12-lead ECG from a single lead (useful for ECG reconstruction of smartwatch experiments), and unsupervised explainable anomaly detection. Numerical experiments show that the combination of $\texttt{BeatDiff}$ and $\texttt{EM-BeatDiff}$ outperforms SOTA methods for the problems considered in this work.


Painted Heart Beats

Adhya, Angshu, Yang, Cindy, Wu, Emily, Hasan, Rishad, Narula, Abhishek, Alves-Oliveira, Patrícia

arXiv.org Artificial Intelligence

We developed a robot arm that collaboratively paints with a human artist. The robot has an awareness of the artist's heartbeat through the EmotiBit sensor, which provides the arousal levels of the painter . Given the heartbeat detected, the robot decides to increase proximity to the artist's workspace or retract. If a higher heartbeat is detected, which is associated with increased arousal in human artists, the robot will move away from that area of the canvas. If the artist's heart rate is detected as neutral, indicating the human artist's baseline state, the robot will continue its painting actions across the entire canvas. We also demonstrate and propose alternative robot-artist interactions using natural language and physical touch. This work combines the biometrics of a human artist to inform fluent artistic interactions.




Bayesian Nonparametric Dynamical Clustering of Time Series

Pérez-Herrero, Adrián, Félix, Paulo, Presedo, Jesús, Ek, Carl Henrik

arXiv.org Machine Learning

Abstract--We present a method that models the evolution of an unbounded number of time series clusters by switching among an unknown number of regimes with linear dynamics. We develop a Bayesian non-parametric approach using a hierarchical Dirichlet process as a prior on the parameters of a Switching Linear Dynamical System and a Gaussian process prior to model the statistical variations in amplitude and temporal alignment within each cluster . By modeling the evolution of time series patterns, the method avoids unnecessary proliferation of clusters in a principled manner . We perform inference by formulating a variational lower bound for off-line and on-line scenarios, enabling efficient learning through optimization. We illustrate the versatility and effectiveness of the approach through several case studies of electrocardiogram analysis using publicly available databases. Index T erms--Time series analysis, Bayesian methods, Gaussian processes, linear dynamical systems, Dirichlet processes, unsupervised learning, electrocardiogram, arrhythmia detection. IME series data analysis has come to pervade all scientific and technological domains, driven by the need to understand change over time. With the growing availability of such data, machine learning has assumed an increasingly central role in a wide variety of tasks which fall under the category of pattern recognition. Particularly, there is growing interest in identifying similar behaviors in time series data as a preliminary step towards generating insights into the dynamics of the underlying processes. Some recent methodologies can be found for characterizing sea wave conditions [1], transcriptome-wide gene expression profiling [2], selecting stocks with different share price performance [3], and discovering human motion primitives [4].


Probabilistic Latency Analysis of the Data Distribution Service in ROS 2

Lee, Sanghoon, Park, Hyung-Seok, Chae, Jiyeong, Park, Kyung-Joon

arXiv.org Artificial Intelligence

--Robot Operating System 2 (ROS 2) is now the de-facto standard for robotic communication, pairing UDP transport with the Data Distribution Service (DDS) publish-subscribe middleware. DDS achieves reliability through periodic heartbeats that solicit acknowledgments for missing samples and trigger selective retransmissions. In lossy wireless networks, the tight coupling among heartbeat period, IP fragmentation, and retransmission interval obscures end-to-end latency behavior and leaves practitioners with little guidance on how to tune these parameters. T o address these challenges, we propose a probabilistic latency analysis (PLA) that analytically models the reliable transmission process of ROS 2 DDS communication using a discrete-state approach. By systematically analyzing both middleware-level and transport-level events, PLA computes the steady-state probability distribution of unacknowledged messages and the retransmission latency. Our findings establish a theoretical basis to systematically optimize reliability, latency, and performance in wireless industrial robotics. Communication has become an increasingly critical factor in modern robotics. Conventional fixed-station robots have long relied on wired links-such as Ethernet-based fieldbuses-for control and data exchange, benefiting from their stability and low latency. For mobile robots and multi-robot systems, however, the need to cut the tether and adopt wireless communication is rapidly growing [1].


Heart Rate Classification in ECG Signals Using Machine Learning and Deep Learning

Vo, Thien Nhan

arXiv.org Artificial Intelligence

This study addresses the classification of heartbeats from ECG signals through two distinct approaches: traditional machine learning utilizing hand-crafted features and deep learning via transformed images of ECG beats. The dataset underwent preprocessing steps, including downsampling, filtering, and normalization, to ensure consistency and relevance for subsequent analysis. In the first approach, features such as heart rate variability (HRV), mean, variance, and RR intervals were extracted to train various classifiers, including SVM, Random Forest, AdaBoost, LSTM, Bi-directional LSTM, and LightGBM. The second approach involved transforming ECG signals into images using Gramian Angular Field (GAF), Markov Transition Field (MTF), and Recurrence Plots (RP), with these images subsequently classified using CNN architectures like VGG and Inception. Experimental results demonstrate that the LightGBM model achieved the highest performance, with an accuracy of 99% and an F1 score of 0.94, outperforming the image-based CNN approach (F1 score of 0.85). Models such as SVM and AdaBoost yielded significantly lower scores, indicating limited suitability for this task. The findings underscore the superior ability of hand-crafted features to capture temporal and morphological variations in ECG signals compared to image-based representations of individual beats. Future investigations may benefit from incorporating multi-lead ECG signals and temporal dependencies across successive beats to enhance classification accuracy further.


Leveraging an ECG Beat Diffusion Model for Morphological Reconstruction from Indirect Signals

Neural Information Processing Systems

Electrocardiogram (ECG) signals provide essential information about the heart's condition and are widely used for diagnosing cardiovascular diseases. The morphology of a single heartbeat over the available leads is a primary biosignal for monitoring cardiac conditions. However, analyzing heartbeat morphology can be challenging due to noise and artifacts, missing leads, and a lack of annotated data.Generative models, such as denoising diffusion generative models (DDMs), have proven successful in generating complex data. We introduce \texttt{BeatDiff}, a light-weight DDM tailored for the morphology of multiple leads heartbeats.We then show that many important ECG downstream tasks can be formulated as conditional generation methods in a Bayesian inverse problem framework using \texttt{BeatDiff} as priors. We propose \texttt{EM-BeatDiff}, an Expectation-Maximization algorithm, to solve this conditional generation tasks without fine-tuning. We illustrate our results with several tasks, such as removal of ECG noise and artifacts (baseline wander, electrode motion), reconstruction of a 12-lead ECG from a single lead (useful for ECG reconstruction of smartwatch experiments), and unsupervised explainable anomaly detection.


RIFLES: Resource-effIcient Federated LEarning via Scheduling

Alosaime, Sara, Jhumka, Arshad

arXiv.org Artificial Intelligence

--Federated Learning (FL) is a privacy-preserving machine learning technique that allows decentralized collaborative model training across a set of distributed clients, by avoiding raw data exchange. A fundamental component of FL is the selection of a subset of clients in each round for model training by a central server . Current selection strategies are myopic in nature in that they are based on past or current interactions, often leading to inefficiency issues such as straggling clients. In this paper, we address this serious shortcoming by proposing the RIFLES approach that builds a novel availability forecasting layer to support the client selection process. We make the following contributions: (i) we formalise the sequential selection problem and reduce it to a scheduling problem and show that the problem is NP-complete, (ii) leveraging heartbeat messages from clients, RIFLES build an availability prediction layer to support (long term) selection decisions, (iii) we propose a novel adaptive selection strategy to support efficient learning and resource usage. T o circumvent the inherent exponential complexity, we present RIFLES, a heuristic that leverages clients' historical availability data by using a CNN-LSTM time series forecasting model, allowing the server to predict the optimal participation times of clients, thereby enabling informed selection decisions. By comparing against other FL techniques, we show that RIFLES provide significant improvement by between 10%- 50% on a variety of metrics such as accuracy and test loss. T o the best of our knowledge, it is the first work to investigate FL as a scheduling problem.